• 한국통신학회논문지
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• 제24권6B호
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• pp.1032-1041
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• 1999

본 논문은 단일프로세서 환경에서 부정확 타스크들을 선점형태로 스케쥴할 때 발생하는 오류의 최대치를 최소화하는 온라인 스케쥴링 알고리즘을 제시한다. 알고리즘은 상위수준 및 하위수준 알고리즘으로 나눈다. 상위수준 알고리즘에서는 매번 타스크가 도착할 때마다 스케쥴링을 수행하며, 대상 타스크들의 전체 오류 및 최대오류가 동시에 최소가 되도록 각 타스크들의 수행시간을 구한다. 하위수준 알고리즘에서는 배당된 타스크들의 할당 시간을 실제 프로세서가 어떤 순서대로 수행할지를 정한다. 상위수준 알고리즘은 주어진 조건을 LP 문제로 정형화하여 복잡도가 상당히 개선된 알고리즘을 제시하였고, 하위수준 알고리즘은 Shih and Liu[4] 의 온라인 알고리즘을 확장하였다. 시뮬레이션을 통하여 다수 경우의 상황을 실험한 결과 전의 연구방법 보다 상당히 개선된 효과, 최대오류를 더 최소화시키는 것을 관찰하였다.

• Journal of Information Processing Systems
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• 제11권2호
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• pp.184-204
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• 2015

Fuzzy Formal Concept Analysis (FCA) is a mathematical tool for the effective representation of imprecise and vague knowledge. However, with a large number of formal concepts from a fuzzy context, the task of knowledge representation becomes complex. Hence, knowledge reduction is an important issue in FCA with a fuzzy setting. The purpose of this current study is to address this issue by proposing a method that computes the corresponding crisp order for the fuzzy relation in a given fuzzy formal context. The obtained formal context using the proposed method provides a fewer number of concepts when compared to original fuzzy context. The resultant lattice structure is a reduced form of its corresponding fuzzy concept lattice and preserves the specialized and generalized concepts, as well as stability. This study also shows a step-by-step demonstration of the proposed method and its application.

• 한국정밀공학회지
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• 제16권12호
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• pp.182-189
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• 1999

In this paper, we present an ultrasonic sensor based path planning method using fuzzy logic for obstacle avoidance of an intelligent vehicle in unknown environments. Generally, Robot navigation in unknown terrains is a very complex task difficult to control because of the great amount of imprecise and ambiguous sensor information that has to be considered. In this case, fuzzy logic can satisfactorily deal with such information in quite efficient manner. In this study, we propose two fuzzy logic controller which is composed of steering controller and velocity controller respectively. Our object is to develop a fuzzy controller that can enable a mobile robot to navigate from a start point to a goal point without collisions, in the least possible travel time. The ability and effectiveness for the proposed algorithm will be demonstrated by simulation and expeiment.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1995년도 춘계학술대회
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• pp.127-130
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• 1995

Chromosome analysis is an important and difficult task for clinical diagnosis, for mutagen dosimetry, and for biological research. It is expensive, time consuming and imprecise when performed manually. Efforts lo automate some or all of the procedures have continued for more than 30 years, with only limited success. An acquiring sample from chromosome group is not solved with automatic method. It is still performed by user. This paper represents the method of an automatic chromosome sample extraction which based on region splitting, and scan converted method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.661-663
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• 1995

Chromosome analysis is an important and difficult task for clinical diagnosis for mutagen dosimetry, and for biological research. It is expensive, time consuming and imprecise when performed manually. Efforts to automate some or all of the procedures have continued for more than 30 years, with only limited success. An acquiring sample from chromosome group is not solved with automatic method. It is still performed by user. This paper represents the method of an automatic chromosome sample extraction which based on region splitting, and scan converted method.

• Smart Structures and Systems
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• 제16권2호
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• pp.295-328
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• 2015

In recent years the monitoring of structural behavior through acquisition of vibrational data has become common practice. In addition, recent advances in sensor development have made the collection of diverse dynamic information feasible. Other than the commonly collected acceleration information, Global Position System (GPS) receivers and non-contact, optical techniques have also allowed for the synchronous collection of highly accurate displacement data. The fusion of this heterogeneous information is crucial for the successful monitoring and control of structural systems especially when aiming at real-time estimation. This task is not a straightforward one as measurements are inevitably corrupted with some percentage of noise, often leading to imprecise estimation. Quite commonly, the presence of noise in acceleration signals results in drifting estimates of displacement states, as a result of numerical integration. In this study, a new approach based on a time domain identification method, namely the Unscented Kalman Filter (UKF), is proposed for correcting the "drift effect" in displacement or rotation estimates in an online manner, i.e., on the fly as data is attained. The method relies on the introduction of artificial white noise (WN) observations into the filter equations, which is shown to achieve an online correction of the drift issue, thus yielding highly accurate motion data. The proposed approach is demonstrated for two cases; firstly, the illustrative example of a single degree of freedom linear oscillator is examined, where availability of acceleration measurements is exclusively assumed. Secondly, a field inspired implementation is presented for the torsional identification of a tall tower structure, where acceleration measurements are obtained at a high sampling rate and non-collocated GPS displacement measurements are assumed available at a lower sampling rate. A multi-rate Kalman Filter is incorporated into the analysis in order to successfully fuse data sampled at different rates.

• 한국컴퓨터정보학회논문지
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• 제9권4호
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• pp.203-214
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• 2004

본 연구에서는 정보시스템 프로젝트 계획모형에서의 가능성 계획법 적용을 제시하고 있다. 정보시스템 프로젝트 계획모형에서 관리자와 의사결정자들은 불명확한 정보나 주관적 견해로 인해 흔히 일정계획, 비용, 성능(품질)과 같은 모수의 추정에서 많은 어려움을 겪게 된다. 이러한 경우 가능성 의사결정모형은 현실적 의사결정모형에서 적용 가능한 해법을 제시할 수 있게 된다. 본 연구에서 적용된 CPM은 프로젝트가 완료되는 시점을 결정하고 프로젝트를 수행하기 위해 각 활동들의 수행시작 일정을 수립하는 데 목적이 있는 기법이다. 가능성 계획법을 적용한 CPM(Critical Path Method)에서는 의사결정자의 열망수준, 의사결정상의 애매함을 고려할 수 있으며, 계산상의 효율성도 제고할 수 있다. 본 모형은 GINO을 이용하여 해를 구하였으며, 수치 예와 해가 제시되어졌다.

• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.642-652
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• 2007

Many contracting firms and project managers in the construction industry have started to utilize multi objective optimization methods to handle multiple conflicting goals for completing the project within the stipulated time and budget with required quality and safety. These optimization methods have increased the pressure on decision makers to search for an optimal resources utilization plan that optimizes simultaneously the total project cost, completion time, and crashing cost by considering indirect cost, contractual penalty cost etc., practically charging them in terms of direct cost of the project which is fuzzy in nature. This paper presents a multiple fuzzy goal programming model (MFGP) that supports decision makers in performing the challenging task. The model incorporates the fuzziness which stems from the imprecise aspiration levels attained by the decision maker to these objectives that are quantified through fuzzy linear membership function. The membership values of these objectives are then maximized which forms the fuzzy decision. The problem is solved using LINGO 8 optimization solver and the best compromise solution is identified. Comparison between solutions of MFGP, fuzzy multi objective linear programming (FMOLP) and multiple goal programming (MGP) are also presented. Additionally, an interactive decision making process is developed to enable the decision maker to interact with the system in modifying the fuzzy data and model parameters until a satisfactory solution is obtained. A case study is considered to demonstrate the feasibility of the proposed model for optimization of project network parameters in the construction industry.