Proceedings of the Korean Operations and Management Science Society Conference (한국경영과학회:학술대회논문집)
The Korean Operations Research and Management Science Society
- Semi Annual
Domain
- Economics/Management > Management Information/e-Business
1996.04a
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Performance of the group cumulative sum(CUSUM) control scheme using multiple univariate CUSUM charts is more sensitive to the change of quality control(QC) characteristics than the control chart scheme based on the Hotelling statistics. We examine three group charts for multivariate normal data sets simulated with various correlation structures and shift directions in the mean vector. These group schemes apply the orginal measurement vectors, the scaled residual vectors from the regression of each variable on all others and the principal component vectors respectively to calculating the CUSUM statistics. They are also compared to the multivariate QC charts based on the Hotelling statistic by estimating average run lengths, coefficients of variation of run length and ranks in signaling order. On the basis of simulation results, we suggest a control chart scheme appropriate for specific quality control environment.
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Shewhart control chart is a basic technique to monitor the state of a process. We observe observations of a group of size four or five in a rational way and plot some statistics (e.g., means and ranges) on the chart. When setting up the control chart, the control limits are calculated based on preliminary 20-40 samples, which were supposedly obtained from stable operating conditions. But it may be hard to believe, especially at the beginning of constructing the chart for the first time, whether the process is stable and hence all samples were generated under the homogeneous operating conditions. In this report we suggest a mechanism to obtain robust control limits under self-criticism. When outliers are present in the sample, we obtain tighter control limits and hence increase the sensitivity of the chart. Examples will be given via simulation study.
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If the LP problem doesn't have the optimal soultion uniquely, the solution fo the primal-dual barrier method converges to the interior point of the optimal face. Therefore, when the optimal vertex solution or the optimal basis is required, we have to perform the additional procedure to recover the optimal basis from the final solution of the interior point method. In this paper the exisiting methods for recovering the optimal basis or identifying the optimal solutions are analyzed and the new methods are suggested. This paper treats the two optimal basis recovery methods. One uses the purification scheme and the simplex method, the other uses the optimal face solutions. In the method using the purification procedure and the simplex method, the basic feasible solution is obtained from the given interior solution and then simplex method is performed for recovering the optimal basis. In the method using the optimal face solutions, the optimal basis in the primal-dual barrier method is constructed by intergrating the optimal solution identification technique and the optimal basis extracting method from the primal-optimal soltion and the dual-optimal solution.
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Penalty technique perhaps is the most common technique used in the genetic algorithms for constrained optimization problems. In recent years, several techniques have been proposed in the area of evolutionary computation. However, there is no general guideline on designing penalty function and constructing an efficient penalty function is quite problem-dependent. The purpose of the paper is to give a tutorial survey of recent works on penalty techniques used in genetic algorithms and to give a better classification on exisitng works, which may be helpful for revealing the intrinsic relationship among them and for providing some hints for further studies on penalty techniques.
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암호행렬은 행렬을 구성하고 있는 원소들의 특정한 조합이 암호를 형성하는 행렬로서 실제적인 문제를 해결하기 위한 수단으로 개발된 바있다. 암호행렬은 구성원소들이 서로 긴밀하게 연관되어 있다는 점에서 여러 흥미로운 특성을 갖게 되는데 이러한 특성은 암호행렬을 필요에 따라 형태변환 시킨다든지 하는 것에 이용할 수 있다. 본 연구에서는 이러한 암호행렬의 생성에 기본이 되는 서로 맞물린 수열의 성질에 대해 우선 간략히 살펴보고 이러한 성질에 의해 특징지워지는 암호행렬의 특성을 체계적으로 규명함으로써 암호행렬이 향후 여러방면에서 응용되기 위한 이론적 배경을 마련하고자 한다.
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This paper presents a multi-pass heuristic for job shop scheduling with due dates. The proposed heuristic iteratively improves solutions based on operation due dates. To find a good solution efficiently, a method for searching the neighborhood of current schedule is developed. The heuristic is compared with two existing heuristics as well as several dispatching rules in terms of solution quality and computation time. The experimental results show that the proposed approach is promising.
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We deal with a design problem of assembly/disassembly (AD) systems with finite buffer capacities where the times between failures, the times to repair, and the processing times are exponentially distributed with different parameter values. We present a solution procedure for finding the minimum cost configuration which achieves a desired throughput rate for an AD system. The configuration is defined by the types of machines to be used and capacities of buffers in the AD system. Results of computational experiments on randomly generated test problems show that the proposed heuristics give relatively good configurations in a reasonable amount of time.
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In most dynamic manufacturing environments today, systems and processes are constantly changing. Simulation tools are required that can accurately model the system in detail, but still be easy to use, and allow rapid model redevelopment to react quickly for system changes. An object-oriented simulation modeling environment is presented to provide flexible modeling capabilities for simulation. Also, when simulating an assembly system, a large number of factors must be considered. Because of such complexities, simulation has been used as the primary method in designing, planning and analyzing. In this paper, the dynamic manufacturing environment is discussed for the assembly system. Also, an application method of simulation tools is presented with the experimental data from the automobile manufacturing shop to improve the productivity effectively.
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Cold rolling mill process in steel works uses stands of rolls to flatten a strip to a desired thichness. At Pohang Iron and Steel Company (POSCO) in Pohang, Korea, precalculation determines the mill settings before a strip actually enters the mill and is done by an outdated mathematical model. A corrective neural network model is proposed to improve the accuracy of the roll force prediction. Additional variables to be fed to the network include the chemical composition of the coil, its coiling temperature and the aggregated amount of processed strips of each roll. The network was trained using a standard backpropagation with 2,277 process data collected form POSCO from March 1995, then was tested on the unseen 200 data from the same period. The combined model reduced the prediction error by 55.4% on average.
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The values measured at different time and enumerated sequentially by homogenous interval is called time series. Its goal is to predict values in future by analysing the measured values in past. The stastical approach to time series prediction tend to be by a neural approach with difficulties in expressing the reationship among past data. In neural approach, the preblem is the acquisting of the enough training data in advance. The goal of this paper is that such problem is solved by generating another term as virtual term between terms in time series.
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본 연구에서는 반복 학습제어 이론을 기초로 하는 하이브리드 신경망 제어기를 제안한다. 신경망으로는 백프로퍼게이션(backpropagation) 신경망을 사용하고, 기존의 반복 학습 제어 이론의 단점을 보안한 제어 알고리즘을 제안한다. 백프로퍼게이션 신경망의 맵핑(mapping)의 특징으로 원하는 목표 패턴에 추종할 수 있는 출력 패턴을 생성하고 반복 학습에 소요되는 학습시간을 줄일 수 있다. 실험결과에서 보듯이 제안된 제어 알고리즘은 목표패턴에 수렴함을 알 수 있다. 제시한 알고리즘은 CD-ROM 드라이브와 같은 광디스크 드라이브류의 초점 제어 등에 응용할 수 있다.
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When data is classified and each class has weight, the mean of data is a weighted average. When the class values and weights are trapezoidal fuzzy numbers, we can prove the weghted average is a fuzzy number though not trapezoidal. Its 4 corner points are obtained.
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In this paper we study the problem of augmenting a physical network to improve the topology for new survivable network architectures. We are given a graph G=(V,E,F), where V is a set of nodes that represents transmission systems which be interconnected by physical links, and E is a collection of edges that represent the possible pairs of nodes between which a direct transmission link can be placed. F, a subset of E is defined as a set of the existing direct links, and E/F is defined as a set of edges for the possible new connection. The cost of establishing network
$N_{H}$ =(V,H,F) is defined by the sum of the costs of the individual links contained in new link set H. We call that$N_{H}$ =(V,H,F) is feasible if certain connectivity constrints can be satisfied in$N_{H}$ =(V,H,F). The computational goal for the suggested model is to find a minimum cost network among the feasible solutions. For a k edge (node) connected component S .subeq. F, we charactrize some optimality conditions with respect to S. By this characterization we can find part of the network that formed by only F-edges. We do not need to augment E/F edges for these components in an optimal solution. Hence we shrink the related component into a node. We study some good primal heuristics by considering construction and exchange ideas. For the construction heuristics, we use some greedy methods and relaxation methods. For the improvement heuristics we generalize known exchange heuristics such as two-optimal cycle, three-optimal cycle, pretzel, quezel and one-optimal heuristics. Some computational experiments show that our heuristic is more efficient than some well known heuristics.stics. -
It is generally recognized that Video On Demand (VOD) service will become a promising interactive service in B-ISDN. We consider a hierarchical two level network architecture for VOD service. The first level consists of connected Local Video Servers(LVSs) in which a limited number of high vision programs are stored. The second level has one Central Video Server(CVS) containing all the programs served in the network. The purpose of this paper is to analyze the network traffic and to propose the storage policy for LVSs. For this purpose, we present an analysis of program storage amount in each LVS, transmission traffic volume between LVSs, and link traffic volume between CVS and LVSs, according to changing the related factors such as demand, the number of LVSs is also presented on the basis of the tradeoffs among program storage cost, link traffic cost, and transmission cost.
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본 연구는 CAD/CAM에서 3차원 물체를 표현하는 기법중 하나인 Solid Modeling을 구성하는 데이터 구조를 객체지향화 함으로써 보다 효율적이고 유연한 설계개발환경을 제공하고자 한다. 이를 위해서 가장 일반적으로 Solid Modeling을 표현하는 데이터 구조인 기존의 Half-Edge Data Structure를 기본모델로 하여 점(Vortex), 선(Edge), 면(Face), 입체(Solid)를 객체 Class로 하고 Euler Operator를 Method로 하는 객체지향 반모서리 데이터 구조(Object Oriented Half-Edge Data Structure)를 개발하였다.
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Presented in this study is an algorithmic procedure to obtain polyhedral model from a compound surface. The compound surface in this study denotes a collection of trimmed surfaces without topological relations. The procedure consists of two main modules: CAD data interface, and surface conversion to polyhedral model. The interface module gets geometric information from CAD databases, and makes topological information by scanning the geometric information. We are investigating CATIA system as a data source system. In the surface conversion module, a shell(compound surface with topological information) is approximated to a triangular-faceted polyhedral surface model through node sampling and triangulation steps. The obtained polyhedral model should obey the vertex-to-vertex rule and meet tolerance requirements. Since the polyhedral model has a simple data structure and geometry processing for it is very efficient and robust, the polyhedral model can be used in various applications, such as surface rendering in computer graphics, FEM model for engineering analysis, CAPP for surface machining, data generation for SLA, and NC tool path generation.
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This paper focuses on a automation selection of optimal cutting conditions and cycle time for multi-spindle metal cutting machines based on machining parameters and tool change schemes which are the two most common terms used in the metal cutting. In this research we used two step generative approach, step 1 is mathematical modeling for the selection fo optimal cutting conditions and the other is GMDH-Type modeling to estimate the system performance evaluation. We developed computer programs for these models and the fitting manufacturing examples are applied to this model and it was shown that the proposed approach has a good potential and offers a valuable tools to analyse the metal cutting system.
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FMS(Flexible Manufacturing System)는 NC와 같이 다양한 종류의 공정을 수행할 수 있는 가공장비들이 자동화된 물류 운반 시스템(Material Handling System)으로 연결되어 있어 집중화된 제어 및 운용 시스템에 의해 여러 종류의 다양한 부품들을 동시에 가공할 수 있는 생산시스템으로 정의할 수 있다. FMS의 도입을 고려 중인 기업이 초기단계에서 가장 먼저 직면하게 의사결정 문제는 부품선정 문제이다. 즉, 현재 생산하고 있는 부품들 중에서 혹은 새로이 생산할 부품들 중에서 어떤 부품을 가공할 것인가를 결정하여야 한다. 이 문제의 중요성은 부품선정문제가 FMS의 운영에 필요한 가공장비, 치구 및 공구의 소요량 결정과 관련을 갖게되고 결과적으로는 FMS의 경제적 타당성 평가에 근본적인 영향을 미치게 된다. 본 연구에서는 FMS의 초기설계단계에서의 부품선택문제의 해결을 통한 FMS 경제적 타당성을 평가할 방법론 및 해결 방법을 제시할 것 이다.
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고객의 수요가 매우 다양해지고 제조산업에서의 인건비 비중이 더욱 높아짐에 따라 기존의 생산 시스템은 새로운 변화를 요구하고 있다. 소품종 대량생산 시스템이나 유연생산 시스템 등을 위해 개발되어 온 대부분의 생산 계획은 off-line 상에서 시스템의 모든 요소들이 정상적이라는 가정하에서 수립되었다. 이로 인해서 기계가 갑작스럽게 정지하거나 공구의 이상 현상 등이 발생하여 기 수립된 계획에 따라 작업을 지속하기 힘든 경우가 생길 수 있다. 다양해지는 고객의 요구를 만족시키기 위하여 생산 시스템은 제어 측면에서 고기능화 되어가고 있다. 따라서 이러한 생산시스템의 운영을 위해 적절한 기법이 필요하게 되었다. 본 연구에서는 홀로닉 생산 시스템에 적용 가능한 스케쥴링 기법을 제시한다.
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In general, cellular manufacturing system can be constructed by the following two steps. The first step forms machine cells and part families, and the second step determines cell layout based on the result of first step. Cell layout has to be considered when cell is formed becauese the result of cell formation affects it. This paper presents a cell formation algorithm and proposes an integrated mathematical model for cell formation and cell layout. The cell formation algorithm minimizes the number of exceptional element in cellular manufacturing system. New concept for similarity and incapability is introduced, based on machine-operation incidence matrix and part-operation incidence matrix. One is similarity between the machines, the other is similarity between preliminary machine cells and machines. The incapability identifies relations between machine cells and parts. In this procedure, only parts without an exceptional element are assigned to machine cell. Bottleneck parts are considered with cell layout design in an integrated mathematical model. The integrated mathematical model determines cell layout and assigns bottleneck parts to minimize the number of exceptional element and intercell moving distance, based on linearixed 0-1 integer programming. The proposed algorithm is illustrated by using numerical examples.
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This study is concerned with a heuristic algorithm that can make effectively the machine-part grouping in early stage for designing cellular manufacturing systems. By enhancing the Close Neighbour Algorithm(CNA), the proposed algorithm is concerned with making the machine-part grouping that can maximize machine utilization and minimize part's intercell movement by reducing exceptional elements. The algorithm is tested against existing algorithms in solving several machine-part initial matrices extracted from references and obtained by using random number. Test results shows that a solution matrix of the algorithm has superior grouping efficiency to Close Neighbour Algorithm.
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Application of machine learning to scheduling problems has focused on improving system performance based on opportunistic selection among multitudes of simple rules. This study proposes a new method of learning scheduling rules, which first establishes qualitatively meaningful criteria and quantitatively optimizes the use of them, a similar way as human scheduler accumulate their expertise. The weighting of these criteria is trained in response to the system states through simulation. To mimic human quantitative feelings, distributed fuzzy sets are used for assessing the system state. The proposed method was applied to job dispatching in a simulated FMS environment. The job-dispatching criteria used were the length of the processing time of a job and the situation of the next workstation. The results show that the proposed method can develop efficient and robust scheduling strategies, which can also provide understandable and usable know-hows to the human scheduler.
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This study investigated the length-tension and velocity-force relations of the torso erectors. A myoelectric based approach was used wherein a dynamic biomechanical model incorporating active and passive tissue charactreistics provided music kinematic estimates during controlled sagittal plan extension motions. A double linear optimization formulation from the literatured provided muscle tension estimates. The data supported a linear length-tension relation toward full flexion for both the erector spinae and latissimus muscles. Velocity trends agreed with that predicted by Hill's exponential relation. The results have implications for muscle tension estimation in biomechanical torso modeling, and suggest a possible low back pain injury mechanism.
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An instrumented Glove for Grasp specification in virtual reality based point-and-direct teleroboticsHand posture and force, which define aspects of the way an object is grasped, are features of robotics manipulation. A means for specifying these grasping "flavors" has been developed that uses an instrumented glove equipped with joint and force sensors. The new grasp specification system is being used at the Pennsylvania State University (Penn State) in a Virtual Reality based Point-and-Direct(VR-PAD) robotics implementation. In the Computer Integrated Manufacturing (CIM) Laboratory at Penn State, hand posture and force data were collected for manipulating bricks and other items that require varying amounts of force at multiple pressure points. The feasibility of measuring desired grasp characteristics was demonstrated for a modified Cyberglove impregnated with FSR (Force Sensitive Resistor) pressure sensors in the fingertips. A joint/force model relating the parameters of finger articulation and pressure to various lifting tasks was validated for the instrumented "wired" glove. Operators using such a modified glove may ultimately be able to configure robot grasping tasks in environments involving hazardous waste remediation, flexible manufacturing, space operations and other flexible robotics applications. In each case, the VR-PAD approach improved the computational and delay problems of real-time multiple-degree-of-freedom force feedback telemanipulation.ck telemanipulation.
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Human posture prediction and motion simulation methods try to solve inverse kinematic problems using the optimization technique based on the concept of minimum principle. It is very important to select a cost function which relfects the human posture acurately. In this study, lifting postures were predicted using the five biomechanical cost functions and compared with real human postures in order to evaluate the predictivities of the cost functions. The result showed that all the biomechanical cost functions used in this study could not predict lifting postures accurately. The cost function which minimizes the sum of joint moments showed the smallest mean prediction error, while the one which minimizes the MUR showed statistically better performance.
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Postural tremor of the upper arm in a static posture was measured to provide guidelines of hand tool weight. Three types of camera recording postures were selected. Postural tremor was measured on five levels of tool weights; no weight, 400g, 800, 1200g, and 1600g. For each conditions, upper arm postural tremor was measured together with EMG of biceps, deltoid, and pectoralis major, and Borg's CR-20 scale ratings of perceived exertion. Results of the experiment are as follows; Frequency analysis of tremor revealed that increased amplitude of frequency band of 2-4Hz and 10-14Hz was observed. Postural tremor of the upper arm maintained the initial level until fatigue developed. After the development of fatigue, the rate of the change of postural tremor was significantly increased. Different tool weights and hand postures showed different rate of tremor increase. And time to fatigue and the corresponding endurance time was positively correlated with Borg's RPF scores.
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항공기 개발 기숭이 걸음마 단계에 있는 우리의 현실에서 hardware 제작기술 못지않게 중요한 것이 시스템을 설계하는 software 기술이다. 시스템을 설계하려면 항공기 개발에 관련되는 다양한 정보와 자료의 축적, 그리고 그 자료의 관리를 위한 시스템 구축이 필수적이라 하겠다. 본 연구애서는 조종실 설계연구 진행을 위해 요구되는 다양한 고려사항과 이에 대한 세부 내용을 데이터베이스 시스템으로 구성함으로써 설계 과정의 효율의 극대화를 기하고 또한 계속적인 설계기술의 향상과 방법론의 개발에 도움을 줄 수 있는데 그 목표를 두었다.기본적으로 본 데이터 베이스 시스템은 X형 항공기 개발 과정에서 이루어졌던 연구 내용을 통합하고 있으나 이 시스템 내에 포함되어 있는 설계관련 자료는 특정 항공기에 관계없이 일반적인 설계지침으로도 이용 가능할 것으로 판단된다.
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다른 배경음악의 종류와 수준이 어떻게 컴퓨터 문서편집작업의 수행능력에 영향을 주는지를 알아보기위해 18명의 대학생을 대상으로 2인자 혼합인자 실험계획법을 이용하여 실험을 실시하였다. 실험에 사용된 독립변수로는 "클래식, 록, 그리고 한국민속음악"의 3종류를 갖는 음악형태와 "Low (60~65dB), High(80~85dB)"의 2수준을 갖는 음악크기이며, 분석을 위해 수집된 종족변수치는 문서편집작업의 완료시간 및 작업에러수이다. 분산분석을 이용한 통계분석 결과, 높은 (80~85 dB) 배경음악수준하에서는 낮은 (60~65 dB) 수준에 비해 통계적으로 문서편집작업의 완료시간이 많이 걸렸으며, 특히 록음악이 높은 수준으로 연주될때는 낮은 수준에 비해 유의하게 많은 문서편집작업에러가 발생하였다. 많은 문서편집작업에러가 발생하였다.
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객체지향 기술에서 개면적 모델링을 위해 크게 객체의 정적인 측면과 동적인 측면의 두가지 관점으로 접근하고 있다. 본 연구에서는 시스템의 파악과 구현을 위해 이러한 두가지 이질적인 관점을 나누어 접근하는 것이 아니라 객체의 정적인 측면(Static)과 동적인 측면인 Event를 통합한 방법론을 제시하고 있다.
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Databases are critical to business information systems, and RDBMS is most widely usded for the database system. Normalization has been designed to control various anomalies(insert, update, and delete anomalies). However, normalized databese design does not account for the tradeoffs necessary for the performance. In this research, we develop a model for database desin by denormalization of duplicating attributes in order to reduce frequent join processes. In this model, we consider insert, update, and delete costs. The anomalies are treated by additional disk I/O which is necessary for each insert and update transaction. We propose a branch and bound method for this model, and show considerable cost reduction.
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Database management systems are now used in almost every organization to maintain and utilize important collections of information. Relational DBMSs have a firm theoretical base. However, it lacks important features needed for representing certain critical aspects of an entity. One alternatives to remedy this problem is to adopt the object-oriented approach to the data model development process. In this paper, we tried to show the advantages of object-oriented data model design process for the development of extended relational database schema needed for the integrated plant information system at H. Heavy Industry Co.
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The relational database management systems sometimes require extremely long and complicated queries for a certain retreval. In this case, recursive retirevals are more efficient approach than the usual queries. Many researchers have tried to incorporate semantics in the traditional relational models using artificial intelligence techniques. This new concept becomes a deductive database and sometimes it is also called as a logic programming. However, the designer of a deductive database did not overcome the short of relational database. In this paper, we propose a new way of designing queries for the deductive database. We also provide relations for recursive retrieval in the deductive database. These approaches are applied for the material requirement planning.
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In recent, most of automobile industries adopt the concept of Just In Time production. The paternal manufacturers require their suppliers to supply parts just in time. It is very important for a subcontractor to produce the parts in the appointed time of delivery. This study develops a production information system for Woosin Industry, which is one of such subcontractor of Hundai Motors Company(HNC). The system is developed on Client/Server system. Firstly, three modules are developed, i.e., scheduling module to make a schedule, the subsystem of sales management to deal with the information about order of HMC, delivery of parts, and bill collecting, and the module for supporting material requirement planning and purchace of material.
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본 연구의 목적은 다음과 같다. 첫째, 기업을 중심으로 환경, 조직, 프로세스 등의 기업 내적 외적 요인의 변화와 기업의 상황적 모델을 살펴보고 상황적 모델을 중심으로 기업의 신조직에 대해 조명해 본다. 둘째, 신 조직과 활동기준원가(ABC)를 이용하여 정보시스템 도입의 요건과 기준을 새롭게 정립한다. 셋째, 정보시스템을 구현하기 위한 구체적인 방법론을 모색한다.
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Object-Oriented Modeling Technique (OMT) [1] promotes better understanding of requirements, cleaner designs, and more maintainable systems. A development of Group Decision Support System (GDSS) needs this advantage of OMT. GDSS designed through OMT proposes 3 modelings, object modeling, dynamic modeling, and functional modeling. This paper illustrates a design of GDSS using these 3 modelings. By exploiting the object-oriented paradigm, this design results in a highly system-independent design. And this paper shows some implementation issues including a tip of C++ code.
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일반적으로 한 제품은 원자재로부터 중간의 여러 단계의 공장을 거쳐 최종 완제품으로 시장에 선보이게 된다. 이러한 다공장 구조에서는 제조기업 전체차원, 하부 공장차원, 단위작업장 차원을 유기적으로 연결하여 생산계획 및 생산통제를 담당하는 운영시스템이 필요하다. 본 연구에서는 Jacobson[2]의 Use Case Driven기법을 이용하여 이러한 다공장의 계층적 구조를 가진 생산계획및 통제시스템에 대한 객체지향적 분석 및 설계을 수행하였다. 우선 각 계층의 시스템에 대하여 Actor와 Use case를 도출하였다. 그리고 도출된 Use-case로 부터 객체를 규명하여 시스템에 대한 분석모델을 수립하였다. 또한 주요 Use-case를 규명된 객체간의 메시지 교환과 통제의 이행과정을 통하여 표현함으로써 시스템의 객체지향적 구현의 기반을 구축하였다.
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R'||'&'||'D project management is a process of decisions concerned with the achievement of goals of objectives. Especially, defense R'||'&'||'D project planning is the key in the successfull management of defense development. The defense project managers are constantly having to perform "what if\ulcorner" exercise, such as what if the project is extended out for an additional cost\ulcorner In this reserch, we developed a schedule-cost analysis model based upon Critical Path Method(CPM) and Venture Evaluation and Review Technique(VERT) for schedule-cost trade off analysis defense R'||'&'||'D projects. In the first step, a deterministic model is developed as a heuristic which deterministic model is developed as a heuristic which determines the schedule extension and reduction cost as a function desired schedule. In the second step, a stochastic network simulation model is developed to analyse the project risk (sucess and failure). The expected time and cost can be determined for desired schedule under the assumptions of stochastic arc data (time and cost) with a various precedence relationships. This model provides the defense R'||'&'||'D managers with an estimated and expected cost for curtailing or extending a project a given amount of time. The effectiveness and efficiency of the proposed methods, a heuristic and stochastic networks simulations, have been demonstrated through examples.
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This study presents a R&D performance monitoring system (RDMS) that is applicable for managing nuclear program in KAERI. The prime goal of RDMS is to furnish project manager with reliable and accurate information on status of progress, performance and resource allocation, and attain traceability and visibility of project implementation for effective project management. In this study, the work breakdown structure (WBS) as the governing factor for integration of scope, schedule, resource data was derived, and the above parameters were loaded personal computer. A RDMS is comprised of about 12,000 R&D activities of the 16 goverment-led projects. The Primavera software was used to monitor the progress, evaluate the performance and analyze the resource distribution to activities.
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최근 소비자의 요구가 다양해짐에 따라 이에 대응하기 위한 경영 전략들 역시 다양해지고 있다. 이중 CALS는 비지니스 리엔지니어링(Business Process Reengineering), 동시공학(Concurrent Engineering), CIM(Computer Integrated Manufacturing)등의 여타 경영혁신 기법들을 모두 수용하면서도, 그 구현에 있어서 인터넷, 수퍼 하이웨이, 정보기술의 표준, 생산자동화등과 같은 구체적인 핵심정보기술의 지원을 받은 새로운 경영전략이다. CALS는 다양한 기술과 전략을 포함하고 있으므로, 이들간의 통합된 구도를 관리할 필요가 있으며, 제품의 전 수명주기를 그 대상으로 하므로 생산공학, 품질공학, 인간공학, 경영공학, 정보공학, 물류공학등의 산업공학적 관점에서 그 효율을 극대화하려는 노력이 절실히 요구된다. 본 논문에서는 CALS에 있어서의 산업공학의 역할을 주지하며, 이에 관련된 연구 방향을 제시하고자 한다.
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In order to accomplish large-size information systems successfully, one of the most improtant factor is the system integration(SI) of individual software projects which consist of the systems. A developer of each project should consider aspects of SI through the development cycle, and a manager of the entire system should manage, control, and evaluate each from a SI point of view. In this research, management models for the system managers, development models for the developers of unit projects, and standardized output documents for the management and evaluation purpose are presented based on the SI concepts.
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Trip-based material handling systems such as AGV systems, lift trucks, etc. are often designed with a given flow matrix (or FROM-TO chart) which is usually treated as the number of loaded trips that the devices must perform per unit time between the stations. In reality, the number of trips that would result from parts flow in a facility is dictated by the transfer batch size, i.e., the number of parts that are transferred from one station to the next in one trip. In this paper, we present analytical and simulation results aimed at determining optimal or near-optimal transfer batch sizes in manufacturing systems.
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Nowadays, most shop floors using industrial robots have many problems such as constructing robot workcell, generating robot arm moving trajectory, etc.. In the case of programming robot-arms for a specific task, shop operator commonly use the teach pendant to record the target position and determine the moving trajectory. However, such a teaching process may result in an inefficient trajectory in the sense of moving distance and joint angle fluctuation. Moreover, shop operators who have little knowledge about robot programming process need a lot of learning time and cost. The purpose of this paper is to propose a user friendly robot programming method to program robot-arms easily and efficiently for shop operator so that the programming time is reduced and a short and stable trajectory is obtained.
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This paper presents an algorithmic approach used in the development of a task-level off-line programming system for the efficient applicaiton of robot. In the method, robot tasks are graphically described with manipulation functions. By applying robot language these graphic robot tasks are converted into commands for the robot. A programming example demonstrates the potentiality of task-oriented robot programming.
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수명시험에서는 시험기간을 단축하기 위해 중도절단(consoring) 방법을 사용한다. 혼합 관측중단방법은 정시에 시험을 끝낼 수 있으며 고장시간을 관찰할 필요가 없다는 장점 때문에 널리 사용되고 있다. 본 논문에서는 제품의 수명이 와이블 분포를 따르고 형상모수를 알고 있다는 가정아래, 혼합 관측중단하에서 생산자 위험과 소비자 위험을 고려한 신뢰도 합격판정 샘플링 계획을 개발하였다. 아울러, 형상모수값에 개재된 불확실성이 실제 생산자 위험과 소비자 위험, 그리고 의사결정까지의 평균 고장개수에 미치는 영향을 민감도 분석을 통해 파악하였다.
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An ALT(accelerated life testing) method is to test a product in over-stressed conditions, and then the test result is extrapolated to an usual (normal stressed) condition. It is the major disadvantage of ALT method that the more extrapolation to an usual condition applies the bigger error is indispensable. Therefore a reliability model combining field failure data and laboratory test data is required in pratice. We propose several methods of estimating the failure rate of a product life which is assumed to follow an exponential distribution. Structural similarity and technological advances are also cosidered. Finally, We derive the acceleratio factor which can be used to predict the failure rate for a new product.
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This paper describes the rotating shift system managed in Korean nuclear power plants and the retrospective analysis procedure of incidents induced by erroneous actions of plant personnel. It also describes the analysis results which include time distribution of erroneous actions occurred under the rotating shift system.
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This paper deals with the method providing an exact solution to the 3-dimensional guillotine cutting stock problem. We suggest a 3-stage sutting method using the property that cubic material has to be cut into 2-dimensional planes firstly. This method requires more stocks that the general guillotine cutting methods but can save work force. By using the 1-dimensional dynamic programming, we reduce the computational time and the memory requirement in the 3-stage guillotine cutting method.
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This paper deals with an (s, S) spare-part inventory model with general leadtime. In the model, if the inventory level falls to a reorder point s, a replenishment order quantity Q is ordered. Assumming that the number of operating units is one and the lifetime of a unit follows an exponential distribution, we derive the expected cost rate and suggest a procedure to obtain the optimal pair of (s, S) minimizing the cost rate.
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This paper presents an EMQ model which determines an optimal production run length in a deteriorating machine. It is assumed that a machine is subject to a random deterioration from an in-control state to an out-of-control state with an arbitrary distribution and thus producing constant proportion of defective items. An average cost function and an optimal production run length are determined. A mistake in previous model is found and discussed. A mistake in previous model is found and discussed. Numerical experiments are carried out to see the behavior of the proposed model depending on the cost factors as well as machine parameters, and some interesting behaviors are observed.
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JIT(just-in-time) 생산시스템은 제조라인의 재공품 재고량을 최소화하고, 필요한 품목을 적시에 필요한 양만큼만 생산하여 공급하는 것을 목적으로 한다. 이러한 시스템은 사용하는 칸반의 수에 따라 single-card kanban system과 two-card kanban system으로 구별할 수 있다. 또한 각 공정이 입력버퍼(input buffer)와 출력버퍼(output buffer)를 갖는 경우와 공정간에 하나의 버퍼를 갖는 경우로 나누어 볼 수 있다. 본 연구는 기계간의 물류(material handling)가 필요한 시점에 즉시 이루어진다는 가정하에 기계간 버퍼가 하나이고, 그 버퍼의 용량이 1인 경우의 single-card kanban의 효율적인 운용방안을 개발하였다. 본 연구의 목적은 생산지시칸반의 회수시기를 적절히 조절하여 생산라인의 이용효율(utilization)을 극대화하고자 하는 것이다. 칸반회수시기 결정을 위한 상황분석의 범위를 10대의 기계로 제한하여 시뮬레이션에 의해 분석하였다. 기존의 칸반운영방식과 생산라인에서의 재고를 최소화하는 운영 알고리듬, 그리고 생산기계의 효율을 최대화할 수 있는 운영 알고리듬을 개발하여 비교.분석하였다.
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This paper addresses the effects of an imperfect production process on the optimal production quantity and quality inspection policies. The system is assumed to deteriorate during the production process. The results are either defective products or machine breakdown whether multiple quality inspection is worth or not. Furthermore, when multiple inspection policy is adopted, the optimal inspection schedule is shown to be equally spaced throughout the production cycle. Exact solution and approximation of the optimal production quantity and approximation of the optimal number of inspection are provided. Finally, to better understand the model of this paper, comparisons between this model and classical EMQ model are provided.
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The job shop scheduling problem has been a major target for many researchers. And, most of the past studies did not consider setup time. In many cases of real manufacturing environment, however, there exists a setup time for each operations. The setup can be divide into two parts, one can be done after job arrival. The setup time based on the latter can be summed together with processing time, but that based on the former can not be. We propose an approximation method based on shifting bottleneck procedure for solving the job shop scheduling problem with sequence independent setup time. It schedules the machines one by one, taking a bottleneck machine among the machines not yet scheduled. Every time after a new machine is scheduled, all schedules previously established are updated. Both the bottlenck search and the schedule updating procedure are based on solving a single machine scheduling problem with ready time, setup time and delivery time iteratively.
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Mathematical programming method for finding optimal solution of job shop scheduling is inadequate to real situation because fo too much computation time. In contrast, dispatching rule is helpful for reducing compuation time but is not guaranted to find optimal solution. The purpose of this paper is to develop a new dispatching rule and procedure to minimize mean flow time whose result is near the optimal solution for job shop scheduling. First step is to select machine which have shortest finishing operation time among the schedulable operations. Second step is to select operation with regard to estimated remaining operation time. The suggested rule is compared with nondelay and MWKR rule for three examples, and is confirmed to be most effective to minimize mean flow time.
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We investigate the scheduling problem for periodic job shops with blocking. We develop Petri net models for periodic job shops with finite buffers. A buffer control method would allow the jobs to enter the input buffer of the next machine in the order for which they are completed. We discuss difficulties in using such a random order buffer control method and random access buffers. We thus propose an alternative buffer control policy that restricts the jobs to enter the input buffer of the next machine in a predetermined order. The buffer control method simplifies job flows and control systems. Further, it requires only a cost-effective simple sequential buffer. We show that the periodic scheduling model with finite buffers using the buffer control policy can be transformed into an equivalent periodic scheduling model with no buffer, which is modeled as a timed marked graph. We characterize the structural properties for deadlock detection. Finally, we develop a mixed integer programming model for the no buffer problem that finds a deadlock-free optimal sequence that minimizes the cycle time.
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이동통신서비스 가입자 수에 대한 예측은 이제까지 주로 확산모형(diffusion model)에 의한 신규가입 자 수의 예측을 위주로 발전되어 왔다. 그러나, 소비자들의 다양한 욕구의 변화 및 관련 기술의 발전으로 인하여 디지털이동전화, 발신전용이동전화 등의 신규 이동통신 서비스들이 시장에 소개됨에 따라 기존 이동통신서비스 가입자들중 다수가 그 서비스를 해지하고 새로운 경쟁 서비스로 전환하게 되었다. 이 경우 특정 이동통신서비스의 기존 가입자 중에서 발생되는 해지자 수를 정확히 예측하는 것은 해당 이동통신 가입자 수를 합리적이고 정확히 예측하기 위해 매우 중요한 문제이나, 기존의 연구에서는 해지자 수의 예측을 확산모형을 확장시켜 적용하거나, 설문조사에 따른 방대한 자료의 분석에 의존하여 왔다. 이에 본 연구에서는 이동통신서비스의 기존 가입자가 지니는 해지 특성을 가입시기에 따른 해지성향과 특정시점의 가입자가 나타내는 해지까지의 가입수명분포로 정의하고, 기존의 해지자 수 자료에서 해지성향 및 가입수명분포를 추정함으로써 해지자 수를 예측할 수 있는 모형을 개발하여, 이를 기존의 아날로그 셀룰라폰의 해지자 수 예측에 적용하였다.
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In this paper, the affecting factors of the access demand for the cellular service are derived, and the access demand function of the cellular service is estimated. The results obtained in this study are as follows: First, the price (access charge) and the income elasticities of cellular services there exists a network externality in cellular communication services. Third, the technological capability of the service provider has played an essential role in expanding the size of subscribers. Fourth, the access demand of cellular communication service is not sensitive to the usage charge. According to the above results, it can be inferred that if the access charge is lowered, the number if subscribers will increase to the critical mass, and then the cellular communication market will grow up to a saturation point naturally.
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B-ISDN is expected to be a main vehicle of future telecommunications. There has been a series fo studies on the demand and the market prospect of B-ISDN services. It is true, however, that they lacked some economic reality since the price of services has been overlooked which is a critical economic factor. In this study, we analyze some aspects of the tariff system of B-ISDN services. First, we explore and summarize the billing parameters of B-ISDN services from diverse characteristics of services and ATM network. These parameters are essential if the services are to be charged based on usage. Secondly, we discuss what factors be considered in the design fo B-ISDN services tariff systems from various points of view shch as traffic charactristics, information types and connection types, etc. The results of this study will offer fundamental insights in the design of B-ISDN service pricing scheme and provide reference for efficient services providing.
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This paper is an exploratory study aimed at finding factors that influence the penetration of cellular mobile telecommunications which have seen rapid development since 1980s. The paper tries to find economy and policy variables to influence the penetration by means of the multiple regression analysis. This paper shows a model that explain the penetration ratio of cellular service. The model is based on data from 39 upper middle income and 39 high income countries. The result shows that GDP per capita and the service period of the cellular mobile telecommunication have influenced on the penetration ratio positively, and the tariff of the service negatively. But, it is the open area to study the impact of the telecommunications policy changes on penetration, and to set a model which could explain the nation-specific characteristics.
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We have developed the drawing and part information management system that could integrate drawing information with corresponding part information in design process. The modules developed include the drawing information management (DIM) and the part information management(PIM). DIM consist of processing drawing management, approved drawing management, disused drawing management, and drawing print management. PIM consist of new part management, option management, and part change management. Errors which may occur in the design process can be reduced by reference to part information directly. In addition, the number of parts can be reduced by minimizing the frequency of new parts generation through the systematic management.
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본 논문은 다품종 소량생산에서 발생하기 쉬운 제품들의 유사성을 근간으로, 제품들의 공통적인 특성을 관리하기 위한 Famiiy BOM 체제를 구현하여 이를 제품의 설계정보관리에 이용할 수 있는 시스템 개발에 관한 것이다. 이 Family BOM을 통해 기존의 개별 제품별 BOM이 가지는 한계를 극복하고 유사 제품을 군으로 묶어 이들의 공통된 특성을 제품의 설계시에 활용할 수 있다. Family BOM은 부품을 군으로 분류하고 이 부품들의 구성을 공통 부분과 선택 부분으로 모듈화하여 표현하는 방법이다. 이 Family BOM을 통해 기존의 제품별 BOM을 별도로 관리하는데 따른 BOM 개수의 증가, 관리 및 변경의 복잡, 데이터의 정확성 부족 등과 같은 문제점을 해결할 수 있다. 본 연구에서는 먼저 부품을 형상 및 공정, 기능의 유사성에 따라 군별로 분류하기 위하여 부품의 특성을 코드화하여 이 코드의 유사성 정도에 따라 분류하는 Classification & Coding system을 개발하였다. 이 기법을 이용하여 유사한 부품을 군별로 관리할 수 있고 이를 통해 기존부품정보를 신제품 개발에 적 용하여 설계에서부터 공정계획 수립까지 시간을 단축할 수 있으며 체계적으로 도면을 관리 및 분석 할 수 있다. 또한 제품군별 BOM관리를 위한 Family BOM을 구현하였고, 이에 따라 도면 중심의 설계정보관리시스템을 개발 하였다.
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특징형상 데이터는 공정설계의 입력 정보로 사용되며, 부품 서술 데이터, 기하학적 데이터, 가공 기술적 데이터로 분류할 수 있다. 또한 공정순서및 작업순서 결정에서 선행관계는 반드시 고려하여 위배되지 않도록 해야하는 중요한 요소이다. 본 연구에서는 작업순서 결정시 만족해야하는 선행관계를 기하형상에 의한 선행관계, 단위 특징형상의 작업내용들간의 선행관계, 가공 경험에 의한 선행관계 등으로 분류/정의하였고, 특징형상 데이터와 가공지식을 이용하여 분류된 선행관계를 자동으로 추출하는 방법을 제안하였다. 그리고 추출한 선행관계를, 공구 교환횟수를 최소로 하는 작업순서 결정 알고리즘에 적용한 사례를 정리하였다.
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공정계획은 숙련된 작업자의 경험의 경험과 지식에 의해서 작성된다. 이러한 과정을 컴퓨터를 활용하여 자동화함으로써 공정계획을 수립하는 시간은 물론 이와 연관된 설계변경, 설비선정, 견적, 재고관리 등 반복적인 업무의 스피드와 정확도를 향상시킬 수 있으며, 비숙련자라도 쉽게 공정을 파악하고 최선의 공정계획을 수립할 수 있다. 자동차 외판제조용 대형 프레스 금형을 대상으로 자동화된 공정계획 시스템을 구현하기 위해 비공식 또는 공식으로 일어나고 있는 공정에 관한 지식을 수집, 분석하여 금형의 패턴과 형구, 부품, 사양으로 분류하여 표준화하였고, 이를 기반으로 공정계획을 컴퓨터가 자동으로 생성할 수 있도록 공정에 관한 Knowledge를 Relational Data Model로 표현하였다. 자동공정계획 시스템은 단계별 Tree 방식으로서, 각 단계마다 시스템이 제공하는 질의에 대해 설계자 또는 공정계획자가 설계도면을 참고하여 이에 대응하면 해당 금형에 대한 적합한 공정계획과 작업공수가 제시되도록 설계 개발되었다.
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The setting of the factory under this study is as the following. There are multiple assembly lines. Each line can handle any of given set of products. Furthermore each line is capable of assembling several products concurrently, i.e. mixed model assembly line. An incoming production order is characterized by its due-date, product type and quantity. Under this setting we first have to select the starting time and the place(assembly line) for an order to be processed. We also have to devise a way to control orders to be manufactured as scheduled. Finally there should be a mean to reschedule orders when something unexpected happens. This paper offers a scheme that provides the above mentioned necessities. It also provides a case where the scheme is applied.
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The factory under this study consists of mixed-model assembly lines and workcenters which provide parts to the main lines. Parts produced by the workcenter have different specifications for different product models. The workcenters fabricate parts in batches, and they are divided into two types. A type 1 center supplies parts only to the main line that is designated to the center while type 2 center provides parts to all the main lines. The purpose of this study is to develop a scheduling scheme for the workcenter, and the main objective of the schedules is to provide parts for the main lines without delay. The facts that make the scheduling challengeable are that 1) the different models existing together on a main line request different parts, 2) the spaces for part inventories are limited and 3) set up times are sequence dependent and long in some cases. This study presents developed scheduling schemes for the type 1 center and explains the scheduling and control structure used.
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The design development, and production of a product is one of the greatest challenges which flexible manufacturing systems face today. No matter how a company refines and controls the manufacturing process, if the product is not properly designed, it will not operate correctly or performed well. Therefore the focus on quality of design must be balanced. One such strategy certain to address the managerial and manufacturing of the future is concurrent engineering. Concurrent engineering calls for the consideration and inclusion of product design attributes satisfying all the design constraints such as customer requirements. Furthermore, concurrent engineering has been recently promoted in many industries as a response to competitive marketing pressures. Viewed as a systematic approach of creating high quality products and bringing them to market at lower cost and in significantly less time, it also attracts the attention of quality designers. In this paperm a methodology and model for optimizing the product design, especially selection of optimal design alternative, is developed. The focus of this paper is on product design as the most critical activity of concurrent engineering. The model is based on the customer requirements for quality. Customer requirements for a certain product can be grouped based on the various design attributes. The design attributes have the priorities. The number of design functions. Design attributes value are calculated, however these values are applied to the optimization method. Numerical example will be illustrated.
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Most manufacturing systems are large and complex. It is natural to divide the control into a hierarchy consisting of a number fo different levels. Each levels is characterized by the length of the planning horizon and the kind of data required for the decision making process. This paper describes an approach for the incorporation of Maintenance times into a hierachical scheduling for a failure prone flexible manufacturing system. The Maintenance should not be performed too often because of the resulting reduction of capacity. The machine failure and preventive maintenance are considered simultaneously.
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본 연구에서는 자동화 제조 시스템 (Automatic Manufacturing System :AMS)의 설계및 구현에 있어서 물리적인 검증 (Physical Validation)을 위한 소프트웨어 시스템의 구조를 제안하고 구현하였다. 제안된 소프트웨어 시스템은 설비들과 물류 흐름에 있어서 간섭 검증과 운영 가능성을 검증하는 기능을 제공하며 크게 4개의 모듈로 나누어져 있다. : 1) 기본 형상들을 이용하여 원하는 형상을 정의하는 "Shape Modeling Module", 2) 실제 설비의 Kinematics와 기능을 모델링하는 "Facility Modeling Module", 3) AMS의 물리적인 배치를 구성하는 "Layout Design Module", 4) 모델링된 AMS를 실행시켜 볼 수 있는 "Factory Emulation Module". 이와 같은 소프트웨어 시스템을 구현하기 위해 수행된 주된 연구는 다음과 같다. : 1) AMS를 구성하는 설비들을 모델링하는 방법을 제시, 2) 표준 설비들의 Instancing Parameter 제시, 3) C++과 GL을 이용하여 소프트웨어로의 구현, 4) Flexible Manufacturing System (FMS)에의 응용.lexible Manufacturing System (FMS)에의 응용.
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The product-user interface for consumer electronic products became complex due to the increased variety of functions corresponding to consumer needs. In this study, three types fo design improvement of the menu interface for a video cassette recorder is studied. Three modifications to an existing menu interface was designed using the semantic, the syntactic and the lexical design factors. A series of the validation experiments was performed to test the effect of the three types of task modifications. The results showed that performance time, number of errors and learning effect were improved for all task modification. It also showed that the performance improvement effect of the semantic factors was 8.8%, that of the syntactic factors was 5.9% and that of the lexical factors was 5.6% respectively. It was found out that the performance improvement effect of the semantic design factors were relatively more significant than the syntactic and the lexical design factors.
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A Global Positioning System(GPS) in an automobile can provide navigational information for identifying the current location of the automobile and helping the drive determine a desirable route to the destination. Usefulness of such a system depends on many design factors. This study examined two critical design factors from a human factors standpoint. The rotation methods and updating schemes of a map were manipulated in a simulated driving environment. Design guidelines are suggested based on the experimental results.
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정보시스템의 가장 큰 목적은 시스템 사용자의 의사결정에 유용한 정보를 제공하는 것이다. 그리고 정보의 유용성 결정은 사용자들의 판단에 근거하므로 사용자의 참여는 시스템 성공에 매우 중요한 변수로 작용하고 있다. 사용자 참여에 대한 기존 연구는 사용자의 참여에 대한 이점을 설명하고 있기는 하나, 메인프레임 환경의 전통적 시스템 개발방법에 근거하고 있으므로 최종사용자 전산환경에서의 사용자 참여에 대한 새로운 조명이 필요하다. 최종사용자 전산 환경에서는 최종사용자의 책임과 권한, 정보의 내용, 친숙한 개발 도구 등으로 인해 시스템 개발 주기의 일정 단계에서의 제한적 참여가 아닌 주체적 참여가 필수적이다. 이러한 개발 환경은 참여자로서의 역할보다는 오히려 개발자로서의 역할이 훨씬 더 강조되는 개념이다. 따라서, 본 연구에서는 개발자로서의 사용자 참여가 발생하는 새로운 환경을 '공동작업'이라고 제안한다. 결론적으로 본 연구를 통하여, '공동작업'의 결과로 인한 정보시스템의 성과를 어떻게 설명할 수 있는가에 초점을 두고 있다. 즉, '공동작업'이 사용자 만족에 어떠한 영향을 미치는가를 고찰하고자 하는 것이다.
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Since most human activities in a nuclear power plant are perfirmed in the main control room (MCR), it is important to have its design well human-engineered, both physically and cognitively. Much research efforts have been given for better, operator-centered designs of human-machine interface in MCR capitalizing today's advanced information technology. Korea is among those who are actively expending such research for the next-generation nuclear plants. This paper analyzes two forerunners among the emerging MCR designs, namely Nuplex 80+ and N4, from the perspective of cognitive systems engineering. Since the two show some fundamental differences in their design concepts, the principles with their pros and cons must be enumerated to benefit our own design of new control rooms. This paper also lists many other decision-making points that emerged due to the new availability of cognitively based on cognitive engineering principles. The future scope and directions of related research are suggested.
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This paper presents how to build a human sensibility database by multivariate method. And, we discribe a fuzzy based inference system which converts human sensibility data to design factors using the human sensibility database. We are able to obtain the values of multiple correlation coeffcient, partial correlation coefficient, and categories by the quantification theory which is multivariate analysis. So, the human sensibility database is constructed from those values. The inference system will be more useful, if the human sensibility database and graphic design factor database were integrated.
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User's sensibility has an important effect upon appreciating household electronic appliances and user's feeling of satisfaction with products has a good effect on the choice of product on purchasing those items. In this point of view, the human-oriented approach of product development system can be adopted as Human Sensibility Engineering. The target of changed development system is to define user's sensibility factors and to apply them to design and development. In this study, the human sensibility ergonomics approach and usability test have been applied to the development and evaluation of an electronic product model.
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To provide an appropriate knowledge representation technique dependent on a particular domain, we consider the combine analytic hierachy process(CAHP). This is an extended method of the conventional AHP which is useful when two different expert groups are involved. Our problem domain is confined to human resource management including such major activities as planning, selection, placement, compensations, performance evaluation, training, and labor-management relations. We prioritize rules, frames, semantic nets, and predicate logic representation techniques best suited to each and all domains through an exploratory study.
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본 연구에서는 기존문헌에서 논의되어온 수리적 매체선택모형의 한계점을 고려하여 의사결정자에게 유용한 매체선택지침을 제공할 수 있는 모형을 구축하고 이를 실제사례에 적용하여 모형의 현실적용성을 살펴본다. 기존의 매체선택모형들은 가정의 현실성 결여와 특정 요인의 단편적 고려 등으로 인하여 실행상의 문제점을 노출하였다. 최근 매체의 이미지, 소비자에 대한 소구, 편집항목 등 매체현상과 관련된 정성적 요소들을 고려하고자 하는 의도에서 AHP를 매체선택 문제에 활용하고 있으며 이것은 매체선택모형을 보다 현실적인 모형으로 만들고 있다. 또한 AHP에 의해 도출된 매체의 선호정도를 독립적으로 이용하는 것보다 정량적인 요소를 고려한 수리적 모형과 결합하는 것이 보다 효과적인 것으로 이해되고 있으며 이는 매체선택모형의 현실적합성을 한층 증가시키고 있다고 할 수 있다. 이러한 정성적 요소와 정량적 요소를 결합한 매체선택모형은 다양한 의사결정요소들을 모형에 포함시켰다는 의미에서 기존의 모형들과 차별화가 이루어지나 실제 모형을 적용하여 그 효과를 판단하는 것은 광고의 복잡성과 측정상의 문제로 인해서 매우 어려운 일로 보인다. 따라서 매체선택 모형은 더 이상 장량적인 관점에서 최적해를 추구하기 보다는 모형이 광고의 상황과 기업의 전략등에 얼마나 효과적으로 대처하는가에 초점을 맞추는 것이 중요하다. 이에 따라 본 연구에서는 AHP와 정수계획법을 결합한 모형을 이용하여 고려하고자하는 매체선택 관련요소들을 체계화하고 이 모형이 최적해를 산출하는 모형으로서가 아니라 의사결정자에게 매체선택지침을 제시하는 하나의 현실적인 의사결정지원도구로서 역할을 하고 있는가에 초점을 맞춘다. (4) 교수-학생간의 인간적인 관계, (5) 숙제 및 과제물과 같은 5가지의 요인으로 구성되어진 것으로 분석되었다. 특히 한국학생을 대상으로 하여 AHP를 이용하여 각 요인들의 수업효과에 대한 상대적 가중치를 조사하였다. 특이한 결과는, 미국학생의 경우 수업준비 및 강의 방법이 상대적으로 중시된 반면, 한국학생들은 미국학생들이 비교적 덜 중시하는 교수-학생간의 인간적인 관계가 수업효과를 높이는데 가장 큰 기여를 하는 것으로 나타났다. 본 연구는 한국 문화의 특징이라 할 수 있는 교수-학생간의 인간적인 관계가 중시되는 교육환경하에서, 정보화 사회의 한 수업형태인 재택수업을 외국(특히 미국)의 방법을 그대로 따라 실시할 경우, 많은 부작용이 있을 수 있다는 것을 암시하며, 따라서 우리 교육문화에 맞는 재택수업 형태의 개발이 시급함을 제시한다고 하겠다.column density of HCaN is (1-3):n1014cm-2. Column density at distant position from MD5 is larger than that in the (:entral region. We have deduced that this hot-core has a mass of 10sR1 which i:s about an order of magnitude larger those obtained by previous studies.previous studies.업순서들의 상관관계를 고려하여 보다 개선된 해를 구하기 위한 연구가 요구된다. 또한, 준비작업비용을 발생시키는 작업장의 작업순서결정에 대해서도 연구를 행하여, 보완작업비용과 준비비용을 고려한 GMMAL 작업순서문제를
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최근들어 금융산업에 있어서 중요한 패러다임의 전환은 정치 경제질서의 변화에 수반되는 개방화 '자율화 추세이며, 국내 금융기관들은 이러한 전환기를 극복하고자 다양한 경영전략을 구사하고 있다. 그 중에서 가장 두드러져 보이는 것이 경영변화 모색을 위한 정보기술의 활용 촉진이며, 이는 어느 산업보다도 정보강도가 높은 금융기관 있어 경쟁우위를 확보하는데 결정적인 힘을 가진다 할 것이다. 본 논문에서는 이와 같은 배경과 정보시스템 평가이론을 바탕으로 금융기관의 정보인프라 (Information Infrastructure) 수준을 측정하고 이 수준이 금융기관의 경쟁력에 어느 정도 영향을 미치는지에 대하여 고찰하고자 하였다. 연구대상 기관은 국내 예금은행중 선발시중은행, 후발시중은행, 지방은행 등 3그룹에서 각각 3개은행씩을 선정하였으며, 정보인프라 수준을 독립변수로 그리고 업무 생산성을 나타내는 직원1인당 부가가치및 정보화지수를 각각 종속변수로 활용하였다. 연구결과 분명한 것은 금윤산업에 있어서 정보인프라의 효율적인 구축이 경쟁우위를 확보하는데 있어 매우 중요한 전략으로 제시될 수 있다는 것이며, 특히 생산성 향상을 지속하기 위해서는 유형의 자원 (Visible Resource)과 아울러 조직, 인력, 전략 등 무형의 자원 (Invisible Resource)에 대한 정책지원이 폭넓게 이루어져야 한다는 것이다.
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The objective of this study is to select reward measure of improved business results. Grain sharing is defined as a compensation system that is designed to provide for variable compensation and to support an employee involvement process by rewarding the members of a group or organization for improvements in organizational performance. Gains, as measured by a predetermined formula, are shared with all eligible employees, typically through the payment of cash bonuses. Generally sales, profit, value-added, cost reduction portion and otherthings have been used as gains, otherwise improved business results, without any proof which is correlated to productivity improvement. This paper suggests which business result is fit reward measure for each business types and sizes.
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한 국가의 과학기술 수준은 그 국가의 현재와 미래를 짐작케 하는 가장 중요한 척도라고 해도 과언은 아니다. 이에 따라 각국은 기술발전을 기하기 위하여 다양한 과학기술 정책을 펴고 있으며, 이러한 정책의 성패 여부는 국가의 과학기술 수준 뿐 아니라 국가의 미래에 지대한 영향을 미치게 된다. 그러나 세계무역기구(WTO)의 출범에 따라 기존의 과학기술 정책에 대폭적인 수정이 불가피하게 되었다. WTO는 공정한 무역질서의 회복을 위한 제반 규율을 대폭 강화하고 있으며, 여기에는 과학기술 정책과 관련한 부분들도 많이 포함되어 있다. 이로 인해 기존의 과학기술 정책에 대폭적인 방향수정이 요구되었고, 각 관련기관에서는 이에 대한 다양한 대응책들을 제시하고 있으나, 이러한 대응책들은 주로 민간 분야와 관련한 것이어서 미흡한 감이 있다. 이는 민간 분야에 파급효과가 지대한 것으로 알려지고 있는 국방과학기술에 대한 정책이 고려되지 않았기 때문이다. 사실 선진국에서는 국방과학기술분야에의 투자를 통해 많은 효과를 얻고 있다. 또한 국방 분야에 대한 문제는 WTO 체제에서 예외로 인정하고 있어, 새로운 환경에 대한 좋은 대응책이 될 수 있다. 그러므로 국방과학기술 정책에 대한 고려가 없는 과학기술 정책은 완전한 정책이라고 할 수 없다. 본 연구에서는 WTO의 출범에 대한 대응방안으로서 국방과학기술 정책의 효율적인 집행을 제안하였다. 이를 위해 우선 WTO의 성격과 WTO 출범으로 야기되는 과학기술 정책및 특히 국방과학기술 정책의 운용시의 변화요인들을 조사하였다. 또한, 국방과학기술 정책의 파급효과를 조사하였으며, 일곱 가지 사용가능한 국방과학기술 정책 대안들을 식별하였다. 또한 식별된 정책 대안들간의 비교를 통하여 효율적인 국방과학기술 정책 방안을 제시하였다.. 문제점들은 HED (Human Engineerign Discrepance) 목록으로 정리하여 설계에 반영하도록 하였다.로 마음의 안정감, 몸의 긴장 이완에 따른 건강 상태 유지, 수업 집중도 향상 등이 나타났다. 위와 같은 종합 적 분석 결과에 따라, 본 연구는 제조 현장의 생산성 향상 및 품질 향상과 연계하여 작업자의 작업 집중도 향상, 작업자의 육체적, 심리적 변화에 따른 생산성 및 품질 향상 변화 정도 등의 산업공학(인간공학) 제 분야의 여러 측면에서 연구 및 적용이 가능하리라 사료된다.l, 시험군:25.90
$\pm$ 7.16mg/d1, 47% 감소)를 나타내었으며, 시험군의 AUC는 대조군에 비해 39% 감소하였고, 혈중 아세트알데히드의 농도는 투여 60분후 시험군(3.96$\pm$ 0.07nmo1/$m\ell$ )이 대조군(6.45$\pm$ 0,64nmo1/$m\ell$ )에 비해 유의성 있는 감소(39%)를 나타내었으며, 시험군의 AUC는 대조군에 비해 48% 감소하였다 한편, 시험관내 에탄올 대사 효소에 대한 바이오짐의 효과를 검색해본 결과 바이오짐(2.0$\mu\textrm{g}$ /assay)에 의해 Aldehyde dehydrogenase(1.5unit/assay)의 활성이 14% 증가되었다. 본 연구의 결과로 볼 때, 비지니스 및 바이오짐은 음주 후 상승된 혈중 에탄을 농도 및 아세트알데히드의 농도를 현저히 감소시키는 효과가 있었다.량 보호 관리, 도시 소공원 개발, 역사 문화 공원 조성, 하천 공간 복원, 공원 시설 기능 개선, 이용 프로그램 개발, 공원 관리 개선, 환경 피해 녹지의 회복, 도시 환경 림 조성, 녹지 -
Human sensibility ergonomics is the technology of measuring human sensibility, applying informaiton to the design of products, systems, and environments for convenient, comfort, and safe human use, and pleasuring human life. This study introduce the research contents and strategy on the human sensibility ergonomics project, which started as one of the national research projects of Korea. The objective of the project is to construct the basis of application technology for human-centered products and environments design in order to enhance the competitive power of the products and the quality of human life. The project consists of three main parts, that is, development of fundamental technology for human sensibility, development of simulator for measurement and evaluation of human sensibility, and development of application technology for products and environments. Total research funds is 70million dollars for 7 years.
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In this paper, a two-stage and top-down approach of mid-term and long-term R&D planning of public corporation is proposed to incorporate some characteristics of public corporation and to overcome the complexity of the real world planning. Unlikely to R&D planning of private company, the total investiment size of public corporation is institutionally determined. A top-down approach is developed to adopt this feature. The proposed approach has two stages to overcome the complexity. In the first stage, we develop a plan for R&D area by adopting the business area and the public role of corporation. In the second stage, we develop the detailed plan within each area. The proposed approach is applied to develop the mid-term and long-term R&D plan of Korea Gas Corporation.
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1995년 5원 31일에 단군이래 최대의 개혁이라고 언론 매체들이 보도할 정도로 혁신적인 교육정책이 발표되었다. 또, 1996년 2월 9일에는 2차 교육 개혁안이 제시되었다. 이런 정책들이 추진되면서 우리나라 대학교육체계가 크게 변화하고 있다. 그 중에서도 학부제의 도입이 대학의 학사제도 개혁에서 최대의 관심사가 되고 있다. 1995년 말에 우리 나라 전대학의 1/3이 넘는 64개 대학이 96학년도부터 학부제를 추진하겠다고 발표하였다. 그러나 대학의 다양화와 자율성이 강조되면서 학부제에는 통일된 모형이 없으며 다양한 모습으로 학부제가 구성되고 있다. 특히 산업공학은 학문의 특성상 인접 학문이 다양하므로 학부제를 구성할 때 소속될 학부의 선택을 어렵게 하고있다. 앞으로 수년 내에 대학 지원 예정자들의 자연 감소와 대학 교육에 대한 사회적인 인식의 변화로 대학 교육 산업에도 소비자 중심시대가 도래하게 된다. 따라서, 학부제의 도입시에 산업공학의 소속과 역할도 소비자 중심 시대에 적합하게 결정되어야 할 것이다. 교육 서비스의 직접 소비자인 대학 입학생들에게 자유로운 전공 선택권을 갖게 하고, 교육 서비스의 간접 소비자인 기업에는 복합 학문의 기술 인력을 제공할 수 있는 학부제의 모형을 제시한다.
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We deal with facility layout problems with shape constraints. A simulated annealing algorithm is developed for the problems. In the algorithm, a solution is encoded as a matrix that has information about relative locations of the facilities in the floor. A block layout is constructed by partitioning the floor into a set of rectangular blocks according to the information while satisfying areas of facilities. In this paper, three methods are suggested for the partitioning procedure and they are employed in the simulated annealing algorithm. Results of computational experiments show that the proposed algorithm performs better than existing algorithms, especially for problems with tight shape constraints.
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POSCO has a plan for facility expansion in plate mill by building No.3 Plate Mill. By No.3 Plate Mill's coming on line, POSCO' current plate production of 2.3 million tons will increase by over 1 million tons to 3.36 million tons (Currently, annual domestic demand for plates is 4.42 million tons). With the plan of facility expansion, POSCO also has the plan of integrating the Plate Warehouse. But, we came to have a question whether the roller table from the mill to the warehouse could carry extended products. Engineers working in the mill wanted to install transfer facility to reduce the load of the roller table, but the engineers in facility purchasing team didn't want to buy the new facility. So, We needed to analyzed the material flow by simulation. The simulation was done on the VAX system by SLAM II. And this project was done by two engineers for 2 months. In the end, we concluded that two transfer facilities are needed for material flow with no bottle neck point.
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In order to reduce the number of rehandles during the loading operation of export containers in port container terminals, the storage location of each arriving container should be determined considering of its weight. We formulate the problem by a dynamic programming model to get the optimal storage location.
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The main objective of this research is to develop the optimal control method for a Distribution Center - multi Branch inventory distribution system. With the continuous review policy, the distribution center places an order for specific order quantity to an outside supplier, and the order quantity is replenished after a certain lead time. Also, each branch places an order for particular order quantity to the distribution center to satisfy the customer demands, and receives the replenishment after a lead time. When an out of stock condition occurs during an order cycle, a backorder is placed to the upper level to fill the unfilled demands. With these situation, variable demand and variable lead time are used for better industrial practice. Futher, actual lead times with a generic lead time distribution are used in developing the control model. Under the actual lead time model, the customer service measures actually attained for the distribution center and each branch are explained as the effective customer service measures. Thus, throughout the optimal control (using computer search procedures), we can set the desired service levels for the distribution center and each branch to produce the effective service level for each branch which is consistent with the goal level of service for each branch. At the same time, the entire distribution system keeps minimum inventories.
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When logistics system is integrated with production system and marketing system, it takes a very important role of the business management. In general, measurement of logistics cost in logistics system uses the conventional cost assignment method. However the conventional method may result in the incorrect cost because the overhead cost may be incorrectly assigned to the products. Activity-Based Costing(ABC) was proposed as an alternative method which will distribute the overhead cost to each cost obeject more accurately. ABC assigns cost to activities based on the amounts of resources used by resource driver, and assigns cost to cost objects based on the amount of activities driver. This study proposes two heuristic algorithms. The first algorithm selects the best activity driver for each cost object by using correlation analysis. The best activity driver is the one that minimizes the sum of loss cost and measurement cost of activity driver. The second algorithm selects the best number of activities by using correlation analysis. The pair of activities with the highest correlation are combined into one if the saving of measurement cost is no less than the loss due to inaccurate distribution of overhead cost. In order to demonstrate the procedure and validity of the algorithms, Real data of one year from a paper manufacturer are used.
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일반적으로 S자 형태의 누적수요곡선을 따르는 단일 신상품과는 달리 다세대 신상품은 세대간의 진화.대체과정에 의하여 다른 형태의 성장곡선을 따른다. Norton & Bass(87)에 의해 개발된 다세대 확산모형은 단일 신상품만을 주로 다루어온 기존의 확산이론을 확장하여 상품들간의 연관관계를 고려한 모형화를 시도하였다는 점에서 큰의의를 지니고 있다. 그러나 Norton & Bass 모형은 누적수요가 감소하는 경우에만 적용 가능한 모형으로 그들이 논문에서 분석한 전세계 반도체 시장의 경우에는 적용될 수 없는 모형이다. 그들은 신규수요를 누적수요모형에 잘못 적용하는 오류를 범하고 있다. 그들이 제안한 모형은 서비스 상품들의 대체를 설명할 수 있는 모형으로 국한된다. 본 연구에서는 재화재의 경우에 적용 가능한 모형을 개발하며 또한 개발된 모형을 Norton & Bass가 잘못 적용했던 전세계 DRAM 시장에 응용한다.
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주문이 매 시점마다 있는 것이 아니라 간헐적인, 즉 어느 시점에는 주문이 있고(ON) 다른시점에는 주문이 없는(OFF) 패턴에서 미래의 주문량에 대한 예측을 고려한다. 다음 시점의 예측량은 우선 주문이 있을 것인가에 대한 판단과 주문이 있다면 어느정도가 예상되는가 하는 문제의 두 가지 측면을 모두 고려해야 한다. 기존의 예측모델은 주문량 자체에 대한 고려가 일반적이며 주문시기에 대한 고려는 전무한 상태이기 때문에 이와 같은 주문패턴을 반영시키는데는 어려움이 따른다고 볼 수 있다. 본 논문에서는 이러한 주문패턴을 마코브 체인으로 모델링하고, 이러한 형태의 상태전이확률(state transition probaility) 추정식이 각각 독립적인 오목함수 (concave function)로 구성되어 있음을 보인다. 또한 확률적으로 표현되는 미래의 주문상태들에 대한 패턴을 확정시키는 알고리듬과 주문량 추정에 있어서 과거의 주문패턴을 반영시키는 모델을 제시한다.
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Regression model with nested error structure interval estimations about variability on different stages are proposed. This article derives an approximate confidence interval on the variance in the first stage and an exact confidence interval on the variance in the second stage in two stage regression model. The approximate confidence interval is based on Ting et al. (1990) method. Computer simulation is provided to show that the approximate confidence interval maintains the stated confidence coefficient.
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고로에서 출선된 용선성분중 [Si]은 노열 판단의 대표인자이며, 용선의 열원역할을 함과 동시에 탈P작업의 저해요인이자 slag발생, 전로 slopping발생의 원인이기에 적절한 저[Si] 용선을 제조할 필요가 있다. 또한 [S]는 강의 불순물이자 수요가의 요구로 저[S] 용선제조가 요구된다. 이를위해 후공정인 제강공장에 가기전에 100% 용선예비처리를 실시하고 있다. 본 연구에서는 기존의 용선성분 분석방법으로는 효율적인 용선 예비처리가 불가하므로 시계열분석및 중회귀분석을 통하여 성분을 사전예측하여 시간의 한계를 극복하고, 예측된 성분에 의하여 효율적인 예비처리실시 또는 예비처리 없이 제강직송도 실시하는등 제철소 공정통제 기능의 하나인 용선관제기능의 적극적인 대응이 가능하도록 한다.
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Plate(후판) design은 수요가 주문시 지정size(두께, 폭)로 부터 당사 압연 process를 거치면서 발생하는 지시대비 실적간의 차이를 보정하여 최종적으로 산출하게 되며, 이러한 과정은 제품생산시 size 부족으로 인한 불량 발생을 방지하는데 그 목적이 있다. Process진행중 size실적은 .gamma.-ray등 각종 측정기기로 부터 자동 측정되며 이는 process computer로 부터 main computer로 일별 전송되어 3개월 동안 조업관리 DATA BASE에 누적관리되고 있다. 본 연구는 이러한 조업실적을 근거로 제조과정에서 발생하는 size오차를 probability theory과 MULTI-REGRESSION 기법을 적용하여 DESIGN LOGIC을 개발, 제품 실수율을 향상하는데 그 목적이 있다.
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Many diseases cause other diseases with strength of influences and time intervals. Prognostic and therapeutic assessments are the important part of clinical medicine as well as diagnostic assessments. In cases where a patient already has manufestations of multiple disorders (complications), progress forecasting and therapy decision by physicians without support tools are very dificult: physicians often say that "Once complications set in, the patient may die". Treating complications are difficult tasks for physicians, because they have to consider all of the complexities, possibilities and interactions between the diseases. The prediction of multiple disorders has many bundles that arise from such time-dependent interrelationships between diseases and nonlinear progress. This paper proposes a model based on time-dependent influences, which appropriately describes the progress of mulitple disorders, and gives some modificaitons for applying this model to medical domains: time-dependent influence matrix manifestation vector, therapy efficacy matrix, S-shaped curve approximation, definitions of which are provided. This research proposes an algorithm for forecasting the state of each disease on the time horizon and for evaluation of therapy alternatives with not toy example, but real patient history of multiple disorders.disorders.
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In solving multi-level knapsack problems, conventional heuristic approaches often assume a short-sighted plan within a static decision enviornment to find a near optimal solution. These conventional approaches are inflexible, and lack the ability to adapt to different problem structures. This research approaches the problem from a totally different viewpoint, and a new method is designed and implemented. This method performs intelligent actions based on memories of historic data and learning. These actions are developed not only by observing the attributes of the optimal solution, the solution space, and its corresponding path to the optimal solution, but also by applying human intelligence, experience, and intuition with respect to the search strategies. The method intensifies, or diversifies the search process appropriately in time and space. In order to create a good neighborhood structure, this method uses two powerful choice rules that emphasize the impact of candidate variables on the current solution with respect to their profit contribution. A side effect of so-called "pseudo moves", similar to "aspirations", supports these choice rules during the evaluation process. For the purpose of visiting as many relevant points as possible, strategic oscillation between feasible and infeasible solutions around the boundary is applied for intensification. To avoid redundant moves, short-term (tabu-lists), intermediate-term (cycle detection), and long-term (recording frequency and significant solutions for diversification) memories are used. Test results show that among the 45 generated problems (these problems pose significant or insurmountable challenges to exact methods) the approach produces the optimal solutions in 39 cases.lutions in 39 cases.
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This paper describes the application of Genetic Algorithms(GAs) to nonlinear constrained mixed optimization problems. Genetic Algorithms are combinatorial in nature, and therefore are computationally suitable for treating discrete and integer design variables. But, several problems that conventional GAs are ill defined are applicaiton of penalty function that can be adapted to transform a constrained optimization problem into an unconstrained optimization problem into an unconstrained one and premature convergence of solution. Thus, we developed an modified GAs to solve this problems, and two examples are given to demonstrate the effectiveness of the methodology developed in this paper.
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Decision environments involve a high degree of uncertainty as well as multiple, conflicting goals. Although traditional goal programming offers a means of considering multiple, conflicting goals and arrives at a satisficing solution in a deterministic manner, its major drawback is that decision makers often specify aspiration level of each goal as a single number. To overcome the problem of setting aspiration levels, chance constrained programming can be incorporated into goal programming formulation so that sampling information can be utilized to describe uncertainty distribution. Another drawback of goal programming is that it does not provide a systematic approach to set priorities and trade-offs among conflicting goals. To overcome this weekness, the analytic hierarchy process(AHP) is used in the model. Also, most goal programming models in the literature are of a linear form, although some nonlinear models have been presented. Consideration of risk in technological coefficients and right hand sides, however, leads to nonlinear goal programming models, which require a linear approximation to be solved. In this paper, chance constrained reformulation with linear approximation is presented for a 0-1 goal programming problem whose technological coefficients and right hand sides are stochastic. The model is presented with a numerical example for the purpose of demonstration.
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This paper deals with finding an initial solution and modifying search direction by the centrering force in the predictor-corrector method which is a variant of the primal-dual barrier method. These methods were tested with NETLIB problems. Initial solutions which are located close to the center of the feasible set lower the number of iterations, as they enlarge the step length. Three heuristic methods to find such initial solution are suggested. The new methods reduce the average number of iterations by 52% to at most, compared with the old method assigning 1 to initial valurs. Solutions can move closer to the central path fast by enlarging the centering force in early steps. It enlarge the step length, so reduces the number of iterations. The more effective this method is the closer the initial solution is to the boundary of the feasible set.
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ITU-T에서 표준 비디오 코딩 알고리즘으로 채택한 MPEG 코딩방식은 세 가지의 코딩방식 (I,B,P,방식)을 주기적으로 사용하기 때문에, 코딩된 정보량에 강한 주기성을 보인다. 본 연구에서는 이러한 MPEG 비디오 트래픽의 주기성을 반영하는 개별 비디오 원의 트래픽을 모형화하고 이를 바탕으로 다중화 장치의 성능분석을 실시하였다. 개별 비디오 원에서 발생된 트래픽은 I, B, P의 코딩순서를 반영하고, I, B, P 프레임 별로 셀 수를 모형화 하였다. 그리고 다중화 장치에 입력되는 트래픽은 프레임 시간 단위로 이산화시켜 셀 수를 모형화하였고, 이를 이산시간 마코프 연쇄를 이용해 다중화 장치에서의 셀 손실률을 구하였다. 다중화 장치에서 셀 손실은 입력되는 잘대적인 트래픽의 양 뿐만 아니라, 비디오 원 정렬 (Source Alignment)에도 많은 영향을 받는다. 이러한 비디오 원의 정렬 효과를 반영하여 다중화 장치에 연결될 수 있는 비디오 원의 수를 결정하였다.
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Recently, some research has been done to analyze the asymptotic behavior of queue length distribution in ATM (Asynchronous Transfer Mode) multiplexer. In this paper, we relate this asymptotic behavior with the asymptotic behavior of decreasing cell loss probability when the buffer capacity is increased. We find with reasonable assumptions that the asymptotic rate of queue length distribution is the same as that of decreasing cell loss probability. Even under different priority control schemes and traffic classes, we find that this asymptotic rate of the individual cell loss probability of each traffic class does not change. As a consequence, we propose the upper bound of cell loss probability of each traffic class when a priority control scheme is employed. This bound is computationally feasible in a real-time. The numerical examples will be provided to validate this finding.
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The tolerance approach to the sensitivity analysis in linear programming considers simultaneous and independent variations in the coefficients of the objective funciton or of the right-hand side terms and gives a region in which the coefficients and terms and gives a region in which the coefficients and terms can be changed and still the current optimal basis B for the original problem remains as an optimal basis for the perturbed problem. In this paper we describe a procedure that expands a region S obtained by the tolerance approch into a larger region R, so that more variations in the objective function coefficients or the right-hand side terms are permissible.
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The cell loss probability recommended in the B-ISDN is in the range of 10
$^{-8}$ ~ 10$^{-12}$ . When a simulation technique is used to analyze the performance of the ATM switching system, an enormous amount of computer time is required. In this study, we derive an importance sampling simulation technique that can be used to evaluate the loss probability obtained by the importance sampling simulation is very close to that obtained by the ordinary simulation and the computer time can be reduced drastically by the importance sampling simulation. -
선박 건조는 선체를 수십에서 많게는 이백여개에 블럭으로 분활하여 각 블럭에 해당하는 원자재를 처리 가공한 후 소조립, 중조립, 그리고 대조립의 과정을 거쳐 블럭으로 완성하여 이들 블럭을 정해진 순서에 맞추어 탑재하는 과정을 거치면서 기타 공정을 완료하여 마지막으로 진수에 이르게 된다. 본 연구에서는 선박 건조 과정에서 탑재 공정 계획을 위한 블럭의 접속 관계를 체계적으로 확립하여 탑재 순서를 생성하는 방법론을 제시하고 이러한 방법론을 바탕으로 초기 탑재 네트워크을 생성 방안을 제시한다.
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Steel making using EAF (Electric Arc Furnace) consists of three major processes: molten steel making, slab casting and hot rolling. Orders from customers, which includes their requirements such as composition, order quantity with allowable range, width, thichness, and unit weight of coils etc, are grouped as charges for EAF to enhance the productivity of the furnace. This paper develops an efficient grouping algorithm for charges in the EAF by exploiting the order characteristics: the allowable ranges of furnace capacity, order quantity, and unit weight of coils. Numerical test shows that the proposed heuristic works very efficiently and the results are quite satisfactory.
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The evaluation test for the operation of rotary type surface mounters which consist of the reel axis, the index table and the X-Y table, has been performed by comparing the new method with the old one in only fields. Because the problem seeking for the optimal operation of rotary type surface mounters, is NP complete, it is almost impossible to get the optimal solutions of large problems. This paper deals with a dynamic network modeling, which can reduce the effort, the cost, and the time used for the performance test of rotary type surface mounters.
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위치등록(location registration)이란, 개인휴대 통신망에서 가입자의 위치정보가 변하는 경우 데이타베이스에 있는 가입자의 위치정보를 갱신해주는 일련의 과정을 말한다. 착신호 접속을 위해서는 시스템이 MS(Mobile Station)의 현재 위치를 알고 있어야 하므로, MS의 위치를 시스템의 데이타 베이스에 저장하는 위치등록 과정이 필요하다. 본 연구에서는 위치등록 방법중 핵심적 요소인 영역기준 위치등록 (zone-based registration) 방법을 다중영역 위치등록 방식으로 구현할 경우의 성능을 분석하였다. 먼저 단일영역 위치등록 방식을 해석하기 위한 이동성 모형을 구축하고 이를 기초로 하여 다중영역 위치등록 방식에 대한 성능분석을 위한 환경을 설정하여 시뮬레이션을 수행하였다. 시뮬레이션 결과를 이용하여 래디오 채널에서의 부하를 최소로 하는 다중영역의 수 N을 구하였다. 개인휴대통신망의 환경에 따라 최적 N의 값은 다소 차이가 있으나 대부분 2-3으로 나타나고 있다. 또한 다중영역 위치등록 방식은 단일영역 위치등록 방식에 비하여 레디오 채널에서의 부하를 10%정도 감소시켜 주는 것으로 나타나고 있다. 본 연구 결과는 개인휴대 통신망에서 중요한 성능요소인 위치등록 처리용량을 향상시키고자 할 경우 효율적으로 이용될 수 있다.
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본고에서는 전용회선서비스 규제완화의 일부인 공전접속의 개방이 가져올 영향에 대해 분석하였다. 분석결과는 다음의 세가지로 대별된다. 첫째, 공전접속 개방으로 인한 공중망 부문의 영향으로, 공중전화망의 통화량의 유출과 통화료 수익의 감소를 추정하였다. 둘째, 전용망 부문의 영향으로, 신규가입에 의한 전용요금 수익의 증가를 추정하였고 마지막으로 공중망 부문의 통화료 감소를 보전하기 위해 설정하게 될 접속부가료에 대해 적정 접속부가료 수준과 규모를 추정하였다.
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An evolution strategy toward digitalized inter-exchange network structure in Seoul Metropolitan areaThis paper analyzes the impact of digitalization on networks in Seoul Metropolitan Area by considering facility investment together with operatinng costs. A stepwise evolution method toward a digitalized double-homming architecture is proposed to accommodate most efficiently with existing analog-oriented networks.
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멀티미디어 통신기술을 이용한 통신 환경의 구축은 초고속, 광대역으로 발전하는 통신기술의 발전과 날로 고도화 되는 컴퓨터 기술의 발달에 힘입어 그 적용범위가 확산되고 있다. 특히 이러한 환경에서 동영상의 통신은 기존의 문자, 그래픽 혹은 정지화상을 이용한 통신에서 보다는 더욱 많은 정보를 사용자에게 이해하기 쉽게 전달한다는 점에서 그 응용분야가 증대되고 있다. 그러나 기존의 동영상 통신에서는 동영상이 화상회의 등의 예에서 보듯이 사용자에게 단순히 영상정보를 제공하는 수단으로서만 이용이 되었다. 진정한 의미의 양방향 통신을 위해서는 이러한 동영상에 대한 사용자의 제어가 가능한 인터페이스가 필요한데, 본 연구에서는 이러한 인터페이스의 구축을 위한 기반기술로써 동영상내의 물체 추적방법에 대해 소개한다. 개발된 방법은 영상의 밝기나 형태변화에 민감하지 않고 추적물체의 모델링을 자동적으로 할 수 있다는 점에서 기존의 영상처리 방법과는 구별된다.
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현재 점점 더 경쟁이 치열해 지고 있는 국내 통신시장에서 경쟁우위를 차지하고 보다 나은 서비스를 통신고객들에게 제시하기 위해서는 고객의 요구를 파악하는 것이 필수적이다. 이를 위해여 본 연구에서는 통신사업에 있어서 설문조사방법과 설문결과를 관리하기 위한 데이타베이스의 프로타입을 제시하고자 한다. 이를 통해 고객의 요구를 파악하고 분석하여 통신회사의 능동적인 대처가 가능하도록 하여 경영전략수립과 고객만족 달성에 효율화를 도모하고자 한다.
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가상경로의 개념은 ATM망의 효율적인 전송체게임이 이미 여러 연구에 의하여 밝혀져 있다[1,2,7,9,10]. 본 논문에서는 등가대역의 개념을 이용하여 가상경로가 가질 수 있는 QoS를 다양하게 고려한 새로운 가상경로 설정모형(MVCAP)과 해법을 제사하였다. 모형 MVCAP은 (1) 가상경로의 설정에 따르는 용량비용(capacity cost)과 제어비용(control cost)간의 trade-off을 반영하였으며 (2) 가상경로의 QoS를 다양하게 고려하여 통계적 다중화 효과를 충분히 반영하도록 하였고 (3) 가상경로의 설정방법들인 분리설정법(segregation method)와 통합설정법(integration method)을 동시에 고려한 모형을 수립하였으며 (4) 등가대역식의 선형근사를 이용하여 목적함수를 단조 감소시키는 발견적 해법을 제시하였다. 소형문제에 대한 실험결과, 본 논문의 모형은 가상경로의 설정을 실시간 안에 이룰 수 있는 가능성을 열어 보였다.
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In machining muliple components fixed on the same pallet of a NC machine, it is very important to minimize the total time required to finish the machining by carefully determining the component layout on the pallet, and the tool path of NC machine, and the sequence of tools to be used. In this paper, a linear integer programming model is presented to obtain an efficient layout; and a two-phased heuristic algorithm is proposed to minimize the total time for machining multiple components. Numerical examples are given for the case of identical components and nonidentical components, respectively. The result of either case shows significant reduction of 7.2~15.0% in the total time required to finish the machining.
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This paper presents the formal integration of process planning and shop floor control with Petri net formalism. Formal integration means that both planning and control problems can be modeled, interfaced, and transformed with the Petri net formalism. This integrated framework provides a systematic approach for rapidly developing a formal shop floor controller from process planning with respect to shop floor configuration.
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Models from different perspectives including functinal view, behavioural view and information view are necessary to implement complex systems such as CIM. It is difficult to integrate those models into a unified framework since they describe different aspects of the system for different purposes. However, modeling from different perspectives is often the case, and many workers are involved in developing a system. Thus, the transformation or interconnection mechanism is required to cope with the consistency problem between them and to save the efforts during development. In this study, a methodology to thansform the IDEFO model into a process flow model is proposed.
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One of the most common communication mechanisms to describe a situation or a process is a story written as an ordered sequence of events or activities. For example, a shop floor supervisor may present the operations of his manufacturing system by describing the processes of manunfacturing a product in his shop. Although IDEF3 is one of the most commonly used methods for describing a business process, but it is not common for a manufacturing process. In this study, we tried to apply IDEF3 for describing a manufacturing process. Problems and suggestions such as selection probability, programmable process modeling, manufacturing resource model were presented.
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This paper describes an intelligent user interface to define simulation models from the process and resource models. It also explains an automatic program generator of discrete event simulation model for shop floor control in a flexible manufacturing system. Especially, the paper is focused on the design and development of methodology to automate simulation modeling from the system description. Describing a shop floor control system in simulation is not an easy task since it must resolve various decision problems such as deadlock resolution, part dispatching, resource conflict resolution, etc. The program generator should be capable of constructing a complete discrete simulation models for a multi-product and multi-stage flow shop containing the above mentioned problems.
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During the last decades, tremendous achievements have been made in the application of Computer-Integrated-Manufacturing(CIM) technologies to the real business fields. It has been recognized as a primary success factor that one should establish its own CIM environments, cultural backgrounds and technology levels. In this paper, an attmpt is made to accelerate the modernization process in a nation-wide range of industries, and so improve the competitiveness of our manufacturing industry as a whole. First of all, various korea-specific CIM concepts which have already been pointed out by industrial CIM practitioners are consolidated. Three major views (activity-based, function-based, and policy-based views) that could be included in the Korea CIM reference model have been derived from the detailed analysis of the technical survey. Twenty-nine research themes with higher priorities in each view are selected.
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The manufacturing system has been changed from labored manual process system, which is managed and operated by managers and operators, to CIMS(Computer Integrated Manufacturing System) for integration of manufacturing, research, development and consumption in the age of diverse customer's needs[6]. However, because it involves the hierarchical system composed of many sub-systems interface and its installation & setup cost is very expensive, CIMS has many difficulties in constructing the durable optimal system that is able to adapt to rapid in-outer circumstance change. So, HMS(Holonic Manufacturing System), the new conceptual manufacturing system having the self-problem-solving and self-organization[11], is instructed to solve these difficulties that it has in these days. The system flexibility in the HMS is able to be ensured, with the integration of human's strong points into mechatronics manufacturing system to reduce interference among sub-systems. In this paper, the manufacturing process rationalization and integration of the assembly line in an automobile industry, has lots of problems in efficiency and productivity, has been studied in an early stage of converting the present state of process system to HMS, which is human-oriented processing system, to improve the line efficiency, system productivity and reliability by using human capability effectively. This paper is derived into the human-oriented & object-oriented holons settlement of the shop floor system composed of processing, assembly and material handling system for the future holonic manufacturing system, which is going to be computer supported control system.
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Manual materials handling and improper working postures are known to be a major cause fo low back injuries, which are one of the major problems in the economic and public health aspects. In this study, two machine repair shops of a manufacturing company in Pohang are selected to investigate the potential hazards of low back injuries. Questionnaire study and worker's strength evaluation are conducted and the results are analyzed. Field workers performing the relatively low stressful jobs were also studied as a control group for comparison with the workers performing the tasks under study.
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Although the tasks are being mechanized or automated today, many taks are still performed manually in serveral indeustrial settings and low back pain has been a social and economic problem. In this study, five machine repair tasks are selected from one manufacturing company in Pohang, which are accountable for relatively high complaints of low back pain. The purpose of this study is to quantitatively evaluate the hazards of the tasks, and finally to recommend the improved methods and guidelines for safe work practices. For most of the tasks under study, workers were found to be exposed to relatively high stresses in low back, mainly due to the heavy objects handled and the improper working postures.
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In this study, the methods and equipment that can be used to detail the anthropomorphic data were developed. This new method that utilizes the Moire' interferometry and image processing technique is less expensive than the conventional methods. We took 36 subjects (18 years to 28 years old). The face area was calculated based on contour information. The cluster analysis about those data enables us to classify our subjects into four groups.
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Information that can be obtained from nuclear power plant trip cases is important for the efforts to reduce the trip occurrences. However, trip case reports, generally printed in documents, have shortcomings in using the contents. A database system called Information System of Trip Event Cases (INSTEC) is being developed to improve the use of trip information. INSTEC will provide the information obtained from the analysis of Korean nuclear power plant trips, such as component failures or human errors that induced the trips, problems contributed to the trips, and the sequence of unit events. In this study, in the process of INSTEC development, information analysis has been performed and a prototype of the system was developed. The prototype of INSTEC with user interface was presented to plant personnel to collect their opinion on INSTEC by using a questioninnaire. As results, it is confirmed that INSTEC would be helpful and useful for plant personnel to review the trip case information.
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The variations of the surface topographical parameters for the analysis of the pedestrian slip and fall accidents during the sliding friction between the specially prepared floor specimens and three working shoes were investigated. The profile ordinate data for each flooring specimen were obtained at 1.1 .mu.m intervals using a laser scanning confocal microscope system along to the direction of sliding. A number of surface roughness parameters, that is, the centre line average (c.l.a.) and root mean square (r.m.s.) roughness, maximum height (Rtm), maximum mean peak height (Rpm), maximum mean depth (Rvm), and average asperity slope were calculated using a computer program and compared with the dynamic friction results. The analysis showed that the surface parameters undergo marked variations during the sliding process, but the variations were statistically significant. It was found that amongst various surface parameters, the maximum depth (Rvm) and the average asperity slope of the asperities were the biggest variation during the sliding proceeding. This result confirms the previous study and may suggests a new approach to monitoring the flooring environments with their service as the effort to reduce the pedestrain slip accident.
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최근까지의 그룹의사결정지원시스템에 관련된 연구와 실제 적용을 통한 실험들에 의하면 각 국가들은 나름대로의 특유한 민족정신과 문화를 가지고 있으며 이러한 문화의 차이로 인해서 서구에서 개발된 그룹 의사결정지원시스템을 우리 기업에 그대로 적용하기에는 그 효과성에 많은 의문점들이 제기되고 있음을 알 수 있다. 따라서 앞으로는 각 국가의 문화적 요인들이 충분히 고려된 고유의 그룹의사결정지원시스템의 개발이 필요하다. 본 연구는 비교경영의 관점에서 문화의 중요성을 제시한 다음 그룹의사결정지원시스템에서 고려되어야 할 민족정신, 국민특성, 문화등의 한국적인 특징들을 기존의 문헌과 연구들을 통해서 규명하고 이 한국적 특징들의 그룹의사결정시스템에 반영하여 우리의 현실에 맞는 효과적인 한국적 그룹의사결정시스템의 구성요소들을 제시한다.
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While a large number of firms have already developed and use an executive information system (EIS) effectively, some firms are reluctant to build one for lack of appropriate and well-organized guidance on how to achieve their own project. In this paper we suggest an EIS development methodology by testing five research hypotheses. As a result, we can conclude that prototyping should be applied to be combined with the SDLC. Moreover the preliminary stage accomplished the highest score in the eight-stage process.
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The level of informaiton provided by most current EIS systems is not above presentation and reporting. To maximize the effect of EIS, we must increase executives' use-rate. To do so, it is important to provide information really required by the user. In a addition, the decision support funcitons should be provided for strategic decision making. In this paper we propose the methodology for adding the analysis and prediciton functions to the EIS that is, for supporting the decision making with the system. Finally, we present a pilot system based on the proposed methodology.
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본 연구는 P사의 사례를 바탕으로 사용중인 중역정보시스템(EIS : Excutive Informaiton System. 이하 "EIS"라함)에서 차별화된 회장전용 시스템의 개선에 대한 연구방법을 소개한다. EIS는 80년대 후반에서 90년도 초반에 이르기까지 급격한 성장을 이룩한 정보시스템이다. 그동안의 EIS가 도입과 보급 단계에서 양적인 성장을 이루었다면, 이제부터는 개선과 발전의 질적인 성장을 이룩하여야 할 필요성들이 점차 커지고 있다. 이러한 시점에서 P사의 EIS가 보다 더 나은 시스템으로 발전하기 위한 토대로, 본 연구는 회장전용의 차별화 된 시스템의 프로토타입을 구성하였다. 또한 본 연구에서는 멀티미디어 기술, 하이퍼미디어 및 슬라이드쇼를 이용하여 차별화된 EIS를 구축하였다. 시스템 구축을 위하여 다양한 아이디어의 도입을 통한 아이디어 기반의 시스템 개발과, 기존 EIS의 정보 전달 형태의 입체화 방안, 갱신 주기별 정보제공 및 전략차별 방안과 정보의 체계적 제공 방안을 근본 연구 추진 방향으로 하여 시스템을 개발하였다. 따라서 본 연구는 현재 개발계획중이거나, 개발중인 EIS에 새로운 접근 방법으로 도움을 줄 수 있을 것이다. 수 있을 것이다.
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The environment surrounded by industries is represented by the 3Cs : Customers, Competition, and Changes. The 3Cs drive industries to pursue external business targets such as customer's needs and marketplaces with BPR (Business Process Reengineering). BPR addresses core business process. One of these core business processes is product development. This product development process has been reengineered by the concept of CE (Concurrent Engineering). The aim of the paper is to build frameworks of CE to clarify the CE concept. This paper begins with investigating the product development process from the perspectives of three drivers: cost, quality and speed. CE frameworks are then followed. The first frmework is concerned with the CE definition and thus three keyphrases are extracted : from the outset, concurrent design and systematic approach. Concerned with the CE implementation, the second framework is composed of five components: generalist & specialist, cross-function team, enabling tools & techniques, success metrics, and total visibility. This paper concludes that the CE practice is hard to achieve because of the 'dont't-tell-them-early' attitude of upstream people, and the 'wait-and-see' attitude of downstream people. As resolution, a change management program is recommended that changes an employees mind-set. This paper also supposes computer systems which facilitate and keep automatic track of the CE process as engineered. Finally it gives a warning that computer systems alone do not guarantee success without being preceded by process re-engineering.
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새로운 기술 활용에 직접적인 영향을 받는 사람들은 기존 사고와 행동을 변화해야 할 필요성을 인식하지만 대개의 경우 현재 상황에 집착하게 된다. 따라서 조직원에게 변화의 방향을 제시하고 이것이 필수적인 것이며 동시에 성취 할 수 있다는 확신을 주어 그들의 사고를 다시 재구성 할 수 있도록 한다면 조직내의 성공적인 변화 관리를 할 수 있다. 본 논문에서는 조직 변화 관리를 성공적으로 실행하기 위하여 변화의 본질을 이해하고, 변화를 방해하는 위험 요소를 최소화 하는 방법론, 구체적인 변화 관리 실행계획 수립 절차, 각 단계별 생성되는 산출물, 진단도구(Tool)를 제시하며, 특히 평가단계에서는 변화의 초기 목표와의 차이 분석을 통하여 조직 전체에 효과를 확장할 수 있도록 필요한 기술, 지식, 태도 등을 추출하여, 변화가 ongoing 프로세스이며 지속적인 개선 활동과 연계되어야 한다는 점에 대해 논한다.
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지난 5년 전부터 국내기업에 도입되기 시작한 'Team제'는 지금에 와서는 대다수 기업들에 적용되고 있다. 그러나 이 'Team제'는 'Restructing' 차원에서 일정 부분 조직의 혁신에 기여한 바가 없지 않으나, 일부 기업에서는 'Team제'의 한계점을 인식하고 또 다른 대안을 모색하고 있는 중이다. 'K' 은행의 경우 금융권에서는 거의 최초로 본부조직에 대해 '전면 팀제'를 도입, 실행하는 과정에서 예기치 못했던 한계에 봉착하게 되었는 바, 'K' 은행은 이를 극복하기 위한 하나의 전략적 대안으로 기존에 구축된 'Downsizing System'을 축으로 '소은행장제'를 도입, 조직의 혁신적 'Restructuring'을 추진하고 있다. 본 논문은 기존에 구축된 'downsizing System'과 'Team' 조직이 고객지향적 시장전략에 발맞추어 어떤 형태로 결합되어 활용될수 있는지를 'K' 은행의 사례를 통해 살펴 보려는데 그 목적이 있다.
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CALS (Commerce At the Light Speed) is considered one of the most important concepts in the 21th century. In the period of CALS, the roles of telecommunication companies to prepare for CALS period. They are: development of facilities management, participation of virtual enterprise prototype, providing teleconference tool, execution of BPR, development fo customer management system.
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Generating a project network of a specific construction project is very time consuming and difficult task in the field. To effectiviely automate and support the planning process, we design a case-based project planning expert system inspired by the fact a human expert project planner uses previous cases for planning a new project. A construction project case consist of its specific characteristics and the corresponding project network (i.e. project plan). Using frame based representation. we represent the project features affecting the progress network and the entities composing the project plan such as the buildings, construction methods, WBS (work breakdown structure), activities, and resources. The project planning process runs through most similar case retrieval, case adaptation, and user requirement satisfaction. We represent the construction domain knowledge for each procedure using constraints and rules. We develop the methodology for constraint-based case adaption. Case adaptation process mainly consist of activity generation/deletion and predecence constraint satisfaction, for which we develop the dynamic constraint generation method and connect user-level requirement representation the system-level network modification knowledge. The methodology is being applied to the prototype for apartment construction project planning.
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Managers are constantly facing problems. Some problems are treated with special connotation. Others are solved as a daily routine. While other problems disppear into the realm of oblivion without even recognized by managers. Some of the unrecognized or overlooked problems may cause a serious failure. It is also likely that there is a better solution approach even though we have been using a generally accepted method. Problem identification is a neglected area by researchers and managers, although they are facing problems everday. This paper provides a review of the theories pertained to problem definition and problem identification as the beginning stage of the problem solving process. Based on these theories, we provide an expert system which can assist managers for a better problem solving. Knowledge base for problem identification and recommaendation of tools for the problem solving is the key ingredient of the expert system.
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본 연구는 위험성이 큰 화학플랜트에서 크실렌 산화공정의 냉각계통에 잠재한 위험성을 HAZOP (Hazard and Operability Studies) 기법을 통하여 잠재한 위험공정부분을 미연에 파악하고 이를 평가하여 안전의 효율성을 높이며, 또한 평가후 이를 전문가시스템을 통하여 취약점을 미연에 파악할 수 있도록 냉각장치의 전문가시스템을 제시하고자 한다.
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본 연구에서는 액체금속로의 핵심구조인 소디움루프를 위한 운전지원 전문가시스템을 개발한다. 소디움루프는 현재 원자력연구소에서 연구 개발 단계에 있으며, 안전 운전을 위한 운전 지식을 연구하고 있는 중이다. 본 논문에서는 이러한 연구 상황에 맞추어 개발되는 전문가시스템에게 요구되는 특징을 정리하고, 소디움루프 운전의 효과적 지원과 운전원의 편의에 중점을 둔 전문가시스템의 개발을 설명한다.
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The issues in developing a sales expert system that assists the customer's purchasing process through the Internet. The required characteristics of the sales expert system and the enabling AI technologies are explained and the current development status of UNIK-SES in KAIST is introduced.
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Neural Network(NN) is known to be suitable for forecasting corporate bankruptcy because of discriminant capability. Bankruptcy prediciton on NN by now has mostly been studied based on financial indices at specific point of time. However, the financial profile of corporates fluctuates within a certain range with the elapse of time. Besides, we need a lot of data of different bankrupt types in order to apply NN for better bankruptcy prediciton. Therefore, we have decided to focus on textiles and clothing industries for bankruptcy prediction with limited data. One part of the collected data was used for training and calibration, and the other was used for verification. The model makes a learning with extended data from financial indices at specific point of time. The trained model has been tested and we could get a high hitting ratio relatively.
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This paper suggests a boltzman machine neural network model to determine model input sequences in line balancing process of mixed model assembly line. We first present a proper energy function, next determine the value of parameters using simulation process.
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Artifical Neural Network(ANN) models were used for forecasting interest rate as a new methodology, which has proven itself successful in financial domain. This research intended to construct ANN models which can maximize the performance of prediction, regarding Corporate Bond Yield (CBY) as interest rate. Synergistic Market Analysis (SMA) was applied to the construction of models [Freedman et al.]. In this aspect, while the models which consist of only time series data for corporate bond yield were devloped, the other models generated through conjunction and reorganization of fundamental variables and market variables were developed. Every model was constructed to predict 1,6, and 12 months after and we obtained 9 ANN models for interest rate forecasting. Multi-layer perceptron networks using backpropagation algorithm showed good performance in the prediction for 1 and 6 months after.
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Korea Composite Stock Price Index (KOSPI) was predicted using Cascade Correlation Network (CCN) model. CCN was suggested, by Fahlman and Lebiere [1990], to overcome the limitations of backpropagation algorithm such as step size problem and moving target problem. To test the applicability of CCN as a function approximator to the stock price movements, CCN was used as a tool for univariate time series analysis. The fitting and forecasting performance fo CCN on the KOSPI was compared with those of Multi-Layer Perceptron (MLP).