• 대한안전경영과학회지
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• 제11권2호
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• pp.153-158
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• 2009

An optimal selection problem of SCM system is one of the critical issues for the company's competitiveness and performance under global economy. This paper presents a hierarchy model consisted of characteristic factors for introducing SCM system and an AHP (Analytic Hierarchy Process) based decision-making model for SCM system evaluation and selection. The proposed model can systematically construct the objectives of SCM system selection to meet the business goals. This paper focuses on selecting an optimal SCM system considering both all decision factors and sub-decision factors of a hierarchy model. Especially, the benefit/cost analysis is applied to choose SCM system. A case study shows the feasibility of the proposed model and the model can help a company to make better decision-making in the SCM system selection problem.

• 한국자동차공학회논문집
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• 제2권4호
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• pp.27-38
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• 1994

In this paper, a simplified model of a hydraulic actuator system for a low-band type active suspension system is derived. To reduce the order of model, time constants of each chamber in hydraulic system are neglected except that of an accumulator. And the dynamics of a spool in the pressure control valve is regarded as a first-order system. The step response and the frequency response of the simplified second-order simulation model exhibit a good agreement with those of the actual system as well as those of the tenth-order simulation model. It is possible to simplify the tenth-order model to the second-order one. The low-band type active suspension model is built up by combining of a quarter car model test rig to testify the validity of the simplified model. The experimental results of suspension characteristics show that the simplified second-order hydraulic actuator model is reasonable to describe the dynamics of the actual hydraulic actuator system for a low-band type active suspension system.

• 한국시스템다이내믹스연구
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• 제1권1호
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• pp.57-79
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• 2000

Most model constructs in organization studies are descriptive in nature, and the conclusions relating to the model behavior over time are speculative. The usefulness of System Dynamics as a methodology for modeling and testing dynamic behavioral hypotheses in organizational behavioral studies is presented, and how to construct a System Dynamics model using simulation software(VENSIM) is shown, The well-know March and Simon motivation model is used to demonstrate the step by step application of System Dynamics to model of this type. The dynamic behavior of the model, both transient and steady state, is obtained, Even though the paper has focused on one model in the area of individual behavior, the approach is general and can be applied to other areas of organizational behavior as will. The usefulness of System Dynamics as a methodology for theory building is identified as well.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.430-432
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• 2004

The standard power system model is needed to test a transmission line protective relay There are two methods to develop a power system model for transmission line protection. First method is based on characteristic power system model, and second method is based on functional power system model. This paper presents a standard power system model for performance test of transmission line protective relay, where the power system model is based on the two methods. And this model is simulated by using RTDS to test a protective relay.

• Journal of Information Processing Systems
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• 제15권6호
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• pp.1335-1349
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• 2019

Crowdsensing technologies can improve the efficiency of smart parking system in comparison with present sensor based smart parking system because of low install price and no restriction caused by sensor installation. A lot of sensing data is necessary to predict parking lot saturation in real-time. However in real world, it is hard to reach the required number of sensing data. In this paper, we model a saturation predication combining a time-based prediction model and a sensing data-based prediction model. The time-based model predicts saturation in aspects of parking lot location and time. The sensing data-based model predicts the degree of saturation of the parking lot with high accuracy based on the degree of saturation predicted from the first model, the saturation information in the sensing data, and the number of parking spaces in the sensing data. We perform prediction model learning with real sensing data gathered from a specific parking lot. We also evaluate the performance of the predictive model and show its efficiency and feasibility.

• 플랜트 저널
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• 제12권4호
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• pp.44-50
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• 2016

실증적인 압축시스템 구현을 위해 관로 유동 모델을 기존의 압축 시스템 모델에 적용하였다. 두 모델의 결합을 위해 압축시스템을 구성하는 압축기, 플래넘, 쓰로틀 벨브 와 각 구성 품을 연결하는 배관의 접점에 적절한 경계 조건을 사용하였다. 본 연구를 통해 관로 유동 모델이 압축 시스템의 안정성에 미치는 영향을 살펴보았다.

• 제어로봇시스템학회논문지
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• 제6권2호
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• pp.121-126
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• 2000

In the fast sampling limit the delta operator model tends to the analog system model. This fundamental property of the delta operator model unifies continuous and discrete time control system. In this paper we study robust linear optimal model following servo system in the presence of disturbances and parameter perturbations. A technique to directly design the generalized differential operator based unified control system that covers both differential operator based continuous time and delta operator based discrete time case is presented. The quadratic criterion function for a linear system is used to design the robust unified servo control system The characteristics of the proposed servo system are analysed and simulated to verify the robustness.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.931-936
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• 1993

Optimal model following control scheme is to design the controller which makes the response of real system follow that of desirable model. This kind of design scheme is developed for first order system. We extends the scheme for second order system regarding the characteristics of mechanical second order system for vibration suppression of flexible structures. The model of mechanical second order system is obtained using suitable damping ratios and natural frequencies. Using this scheme, we can design the good controller which uses the characteristic of second order system. Numerical examples are presented which were used optimal model following control scheme.

• 한국IT서비스학회지
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• 제7권4호
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• pp.231-246
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• 2008

This paper suggests an e-learning system model, a goal-driven personalized e-learning system, which increase the effectiveness of learning. An e-learning system following this model makes the learner choose the learning goal. The learner's choice would lead learning. Therefore, the system enables a personalized adaptive learning, which will raise the effectiveness of learning. Moreover, this paper proposes a SCORM standard, which modifies SCORM 2004 that has been insufficient to implement the "goal driven personalized e-learning system." We add a data model representing the goal that motivates learning, and propose a standard for statistics on learning objects usage. We propose each standard for contents model and sequencing information model which are parts of "goal driven personalized e-learning system." We also propose that manifest file should be added for the standard for contents model, and the file which represents the information of hierarchical structure and general learning paths should be added for the standard for sequencing information model. As a result, the system could sequence and search learning objects. We proposed an e-learning system and modified SCORM standards by considering the many factors of adaptive learning. We expect that the system enables us to optimally design personalized e-learning system.

• 한국정밀공학회지
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• 제12권5호
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• pp.136-148
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• 1995

In this study, a model integration method is pressented as a new method for development of a parametric simulation model. This method enable us to integrate the special simulation models for each production subsystem into a large simulation model. Not only this large simulation model but also each special simulation model for each production subsytem can be used independently. Using this integration method man can reduce the development time and cost for simulation model development. To show the usefulness of this method, a simulation model for a production system with robots is developed by this model integration method. This simulation model is realized by the integration of two special simulation models, one model for a machining subsystem and the other model for a transport subsystem. The modeled production system consists of the robotic cells for machining and a transport subsystem which enable the material flow among the robotic cells. The flow of workpiece in each robotic cell is not fixed. All machines in a robotic cell are only served by robots.