• Proceedings of the Korea Society for Simulation Conference
• /
• 1997.04a
• /
• pp.23-28
• /
• 1997

We discuss development of a simulator for automated manufacturing systems (AMSs) which have sophisticated automated material handling equipments and complicated work flows. The simulator is designed to satisfy the following requirements. A user should be able to easily configure or specify an AMS through a graphical user interface (GUI) and minimal data input. The user should be able to model diverse and complied control logic for automated material handling systems like automated guided vehicle (AGV) systems, robot workcell systems and conveyor systems as well as complicated job flow program. Real time animation is desired. Finally, the simulator should be easily maintained and extended. To satisfy the requirements, we use an object-oriented paradigm for modeling, designing, and programming of the simulator. We use an object-oriented modeling framework to design the modeling elements library, and take the process interaction approach for scheduling processes and events. To model a user-defined diverse control logic, we also develop a script language and its interpreter. We explain design and implementation strategies. We implement the simulator using Visual C++ 4.2 and Open GL on Windows NT and the Windows95. Some modeling examples will be demonstrated.

• Journal of Environmental Science International
• /
• v.19 no.8
• /
• pp.1057-1066
• /
• 2010

An ecological learning center is defined as a place which can establish the correct relationship between human and environment. Human can learn ecosystem and importance of environment throughout observation of nature and participation in program of ecological learning center. The most important aspects of ecological learning center planning are to reflect on user's demand and preservation of ecosystem. The prime goals of this study is to analyze user's characteristics in the Young Wheol Mulmurigol Ecological Learning Center. The second goal of this study is to find out the satisfaction model based on user's perceived performance of each program and facility in the center. For this study, questionnaire survey with 204 individuals was completed. The data from the questionnaire were analyzed statistical method by SPSS. There are several significant results from the study as following First, this ecological learning center as a newly operating facility is used not for educational purpose but for resting and relaxation purpose. It is due to that the most of users in this center are package tourists with historic scenes. Second, user's perceived performance evaluated by 23 attributions of programs and facilities, and these attributions could be classified by 5 factors such as environment friendly design, educational function, preservation of environment, provision of various bio-top and provision of resting area. Third, the user satisfaction model indicates that user satisfaction is depended on various factors such as preservation of environment, provision of various bio-top, provision of resting area. Among these factor affecting the satisfaction, provision of various bio-top is the most influence on user satisfaction.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.5
• /
• pp.2233-2252
• /
• 2018

For the problem of cross-layer joint resource allocation (JRA) in the Long-Term Evolution (LTE)-Advanced standard using carrier aggregation (CA) technology, it is difficult to obtain the optimal resource allocation scheme. This paper proposes a joint resource allocation algorithm based on the weights of user's average quality of experience (JRA-WQOE). In contrast to prevalent algorithms, the proposed method can satisfy the carrier aggregation abilities of different users and consider user fairness. An optimization model is established by considering the user quality of experience (QoE) with the aim of maximizing the total user rate. In this model, user QoE is quantified by the mean opinion score (MOS) model, where the average MOS value of users is defined as the weight factor of the optimization model. The JRA-WQOE algorithm consists of the iteration of two algorithms, a component carrier (CC) and resource block (RB) allocation algorithm called DABC-CCRBA and a subgradient power allocation algorithm called SPA. The former is used to dynamically allocate CC and RB for users with different carrier aggregation capacities, and the latter, which is based on the Lagrangian dual method, is used to optimize the power allocation process. Simulation results showed that the proposed JRA-WQOE algorithm has low computational complexity and fast convergence. Compared with existing algorithms, it affords obvious advantages such as improving the average throughput and fairness to users. With varying numbers of users and signal-to-noise ratios (SNRs), the proposed algorithm achieved higher average QoE values than prevalent algorithms.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.5 no.2
• /
• pp.199-208
• /
• 2009

Mosts of export/import cargo has been moving using maritime transport means. Korea had been driven the system automation project using EDI document since the mid-1990s. However, this automation system comes upon about 40-50% against overall maritime business process, manual or paper document processing work is existing as ever. International e-business environment also has changing into electronic form document transaction from paper document-based transaction. International standardization organization, UN/CEFACT proposed UNeDocs for paperless jtransaction. UNeDocs is a specification to define XML data model as well as electronic form. With UNeDocs, it is not necessary to generate the duplexed data, and it can support user convenient and guarantee the flexibility. This paper defines the UNeDocs data model for EDI and Off-Line processing at the current maritime business. Then, it have to check XML syntax and structure for the defined data model through quality of document check system. Also, it explains the applying plan about the defined UNeDocs data model. It is possible to support paperless transaction as defining UNeDocs-based standard data model and converting into paper document, XML and EDI document using UNeDocs data model.

• Korean Journal of Computational Design and Engineering
• /
• v.6 no.4
• /
• pp.254-262
• /
• 2001

It is not possible to exchange parametric information of CAD (Computer Aided Design) models based on the current version of STEP (Standard leer the Exchange of Product model data). The design intent can be lost during the STEP transfer of CAD models. The ISO Parametrics Group has proposed the SMCH (Solid Model Construction History) schema in June 2000 that includes structures fur exchange of parametric information. This paper proposes the macro parametric approach that is intended to provide capabilities to transfer parametric information. In this approach, CAD models are exchanged in the form of macro files. The macro file contains user commands which are used in the modeling phase. To exchange CAD models using the macro parametric approach, modeling commands of commercial CAD systems are analyzed. Those commands are classified by the grouping method suggested by Bill Anderson. As a neutral file format, a standard modeling commands set has been defined. Mapping relations between the standard modeling commands set and the native modeling commands set of commercial CAD systems are defined.

• Journal of Applied Reliability
• /
• v.15 no.1
• /
• pp.6-11
• /
• 2015

Maintenance plays an important role in keeping product availability, reliability and quality at an appropriate level. In this paper, two-types of maintenance policies are studied following the expiration of two-dimensional (2D) free replacement warranty. Both the fixed-maintenance-period policy and the variable-maintenance-period policy are based on a specified region of the warranty defined in terms of age and usage where all failures are minimally repaired. An accelerating failure time (AFT) model is used to allow for the effect of usage rate on product degradation. The maintenance model that arises following the expiration of 2D warranty is discussed. The expected cost rates per unit time from the user's point of view are formulated and the optimal maintenance policies are determined to minimize the expected cost rate to the user. Finally numerical examples are given to illustrate the optimal maintenance polices.

• Proceedings of the IEEK Conference
• /
• 2000.11c
• /
• pp.121-124
• /
• 2000

In this paper, we propose a pen gesture recognition system for user interface in multimedia terminal which requires fast processing time and high recognition rate. It is realtime and interaction system between graphic and text module. Text editing in recognition system is performed by pen gesture in graphic module or direct editing in text module, and has all 14 editing functions. The pen gesture recognition is performed by searching classification features that extracted from input strokes at pen gesture model. The pen gesture model has been constructed by classification features, ie, cross number, direction change, direction code number, position relation, distance ratio information about defined 15 types. The proposed recognition system has obtained 98% correct recognition rate and 30msec average processing time in a recognition experiment.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.8
• /
• pp.1632-1642
• /
• 1997

In this paper, we studied the effects of the power control imperfection on the system performances of a microcellular DS/CDMA system. The maximum user capacity, defined as the maximum number of users can be serviced simultaneouly, meeting a given voice quality, is first considered. Then the performence degradation due to the control error is analyzed. The frequency selective Raician channel model is used to characterize a microcellular mobile communication environment. The DS/CDMA system under consideration uses BPSK modulation and convolutional coding/Viterbe decoding with soft decision for forward error correction. It is shown that the user capacity falls linearly down with the increase of the power control error(in terms of the standard deviation in dB) and the interference from users outside the third tier cells have a minor effect on the performance. And the performance of DS/CDMA with the imperfect power control model is made to be less than 50% of that with perfect power control moded.

• Journal of Positioning, Navigation, and Timing
• /
• v.11 no.4
• /
• pp.381-388
• /
• 2022

In 2021, development of a regional satellite navigation system called KPS was approved. In this regard, various studies are in progress, but there is no published signal model. So, in relation to the user segment, it is necessary to design a user receiver, but there is no information. Therefore, in this paper, we assume a signal model that can be a candidate signal for KPS based on related studies. This signal uses CNAV-2 structure navigation message, truncated Gold code and BPSK modulation. Based on this signal, a simulator is designed that can be used for receiver design later. The simulator consists of a signal generator and a signal transmitter, and is verified using a software receiver and spectrum analyzer.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.27 no.10
• /
• pp.1644-1652
• /
• 2003

The monitor product is packed by cushioning materials because the monitor can be broken during transportation. However, the addition of the cushioning material increased the volume of the product. Therefore, it is required that the usage of cushioning material be minimized. In practice, design engineers have followed the ad hoc design with experiences of predecessors. Automation of the design process is very important for the reduction of engineering cost, and can be achieved by an excellent design process and software development. According to Axiomatic design, a design flow is defined and a software system is developed for automated design. At first, a basic model is defined. A user can modify the model from menus and design is carried out according to the input from the user. Finite element models are automatically generated based on the design. A nonlinear finite element analysis program called LS/DYNA3D is linked for the impact analysis. The process of Design of Experiments using orthogonal array is installed to minimize the maximum acceleration in drop test. Therefore, a new design can be proposed by the system. The program is designed according to the Independence Axiom of Axiomatic design. FRs and DPs of the software system are defined and decomposed by zigzagging process. Independent modules can be generated by analysis of the full design matrix and each module is coded as class in Object Oriented Programming (OOP). Design results are discussed.