• The KIPS Transactions:PartD
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• v.12D no.6 s.102
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• pp.921-930
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• 2005

In this paper, a general purpose molecular simulation system which has been developed by the author, are described. One of the most advantageous features is that the molecular simulation system can handle a coarse-grained model as well as an all-atom mode. Therefore, we can simulate mesoscopic phenomena as well as microscopic phenomena with the help of Langevin dynamics simulation and dissipative particle dynamics simulation techniques. Thus we could study anesthesia, protein folding, biopolymer flow in microchannel with single framework, which spans from microscopic to mesoscopic scales. We expect that we can also simulate many other bio/nano systems of technological importance which are not feasible by means of molecular dynamics simulation technique. Finally, performance data are shown and a bottleneck is identified for future optimization.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.493-498
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• 2000

The magnetic bearing systems are intrinsically unstable, and need the feedback control of electromagnetic forces with measured displacements. So the controller design plays an important role in constructing high performance magnetic bearing system. In case of magnetic bearing systems, the order of identified model is high because of unknown dynamics included in closed loop systems - such as sensor dynamics, actuator dynamics-and non-linearity of magnetic bearings itself. "Identification for control" - joint optimization of system identification and controller design- is proposed to get the limited-order model which is suited for the design of high-performance controller. We applied the joint identification/controller design scheme to MIMO rigid rotor system supported by magnetic bearings. Firs, we designed controller of a nonlinear simulation model of MIMO magnetic bearing system with this scheme and proved its feasibility. Then, we performed experiments on MIMO rigid rotor system supported by magnetic bearings, and the performance of closed-loop system is improved gradually during the iteration.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.4
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• pp.70-75
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• 2018

This paper describes an Integrate Dynamic Control system with Brake System (IDCB) for SUV vehicles. The system was developed to stabilize the lateral dynamics, maintain the steerability and improve the ride comfort on various roads. A fuzzy logic control method is used to design the IDCB. The performance of the IDCB is validated under different road and driving conditions. The results show that the IDCB tracks the reference yaw rate under all tested conditions; in addition, it reduces the body slip angle and roll angle. When a vehicle runs on a split-${\mu}$ road and a brake input is applied, the IDCB virtually eliminates the lateral dynamics. Thus, the IDCB improves the lateral stability, preserves the steerability and enhances the ride comfort of vehicles.

• Korean System Dynamics Review
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• v.5 no.2
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• pp.175-197
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• 2004

The research studies the classic beer game simulation model from a new perspective. It does so by providing each agent with two ordering policies, and creating a set of rules that allow an agent to change its policy. Such a change is triggered based on an agent's confidence in their own performance, and on the relative confidence of their nearest neighbour. The overall effect is that policy diffusion can occur, where, under certain circumstances, an agent will mimic the behaviour of its neighbour, if it believes that its neighbour is performing better. The motivation behind this research is to provide an experimental base upon which the decision making strategies of business agent can be studied.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.1026-1032
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• 2005

지구온난화 문제의 대표적 원인 물질인 이산화탄소의 배출을 억제 하기 위해 사용할 수 있는 수단 중 하나가 탄소세이다. 탄소세가 부과되면 에너지 집약 산업인 철강 산업에 커다란 영향이 있을 것이 분명하다. 따라서 본 연구는 탄소세 부과로 인한 파급 효과를 시스템 다이내믹스(System Dynamics) 방법에 의한 시뮬레이션 모델을 이용하여 분석하고자 한다. 탄소세 부과 금액, 부과 방법, 신기술 도입을 고려한 시나리오를 설정하여 이에 따른 결과를 분석한다. 또한 에너지 가격 상승률이 다양한 폭으로 변화하였을 때 철강 산업에 미치는 영향에 대해서도 분석한다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.2
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• pp.198-205
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• 2001

Recently, almost all hard disk drives employ the rotary actuator system. The performance of an HDD depends on the accuracy and speed of tracking motion. We study the dynamics of head-suspension assembly during track seek. We develop the numerical analysis program to study the dynamic characteristics of HDD suspension system considering the air bearing effects. The track seek simulation by using the developed program helps to estimate the effect of the suspension vibration on the air bearing dynamics. We calculate the behaviour of the air bearing for the given track seek profile and calculate the positioning error during track seek process due to the lateral deflection of the suspension.

• Korean System Dynamics Review
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• v.11 no.3
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• pp.87-104
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• 2010

This research aims at designing policy alternatives which would facilitate the supply of the national rental housing units, especially targeted for the low-income households who need special types of social support for their residences. In order to illuminate structural characteristics of the national rental housing policies, it heavily depends on collection of secondary survey data, in addition to existing documents. From the institutional dimension, it focuses on major issues related to the residential development, which is pivotal in supplying the required national rental housing units. Furthermore, applying causal loop diagramming techniques derived from the System Dynamics (SD), it tries to divulge dynamic relationships between key stakeholders including the government, developers and tenants. Finally, this research stresses the point that the government should fulfill its basic duty as a financial supporter and the developer should not procrastinate in providing diverse options, timely reflecting tenants' needs.

• Korean System Dynamics Review
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• v.7 no.1
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• pp.229-243
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• 2006

In recent years, due to a lack of expertise, many organizations have been devoting large portions of their budget to outsourcing. Outsourcing is now often regarded as a solution for all problems. However, the lack of clear understanding of the effectiveness of outsourcing could lead to many problems in organizations even though outsourcing is known to provide advantages to some organizations. Moreover, outsourcing could have a negative effect on knowledge management in some aspects. There have been and continue to be numerous studies into outsourcing; however, their findings primarily relate to cost reduction in short-term. Regardless of increasing demands on outsourcing and the importance of knowledge management, little research has focused on decision-making structure from knowledge management perspective. This paper attempted to quickly identify promising movements with potentially significant effects on IT/IS outsourcing.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.535-540
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• 1989

This paper presents an approach for designing a linear multivariable servo mechanism for the case of constant and time varying disturbances. In this paper, we use an "observer-based" approach to consider the disturbance vector as states of the system and the resulting servomechanism design involves the design of an asymptotic observer which estimates both the actual plant states and the disturbance states. The design makes use of switching dynamics instead of switching logics to obtain the sliding mode and from the switching dynamics we can remove the undesirable chattering phenomena.phenomena.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.12
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• pp.1147-1154
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• 2014

Generally, motor controller design is based on its motor dynamics. Therefore, it requires precise information of its motor dynamics. However, most of the low cost DC motors, which are widely used in industries and academia, are provided without such precise information. Even if it is given, the information is mostly imprecise. Following circumstances require one to calculate the motor dynamics information for oneself. This paper presents a simple method to readily apprehend the DC motor dynamics. First, how to establish the model of DC motor dynamics along with the model parameter identification is presented. Then, the parameter values are finetuned until the simulation response based on the dynamics model is close to the experimental response of the motor. Finally, the controller is designed with the established dynamics model. The validity of the designed controller is confirmed by the comparison of the experiment and simulation.