• 한국자동차공학회논문집
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• 제5권5호
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• pp.73-85
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• 1997

An automatic transmission is an important element of automotive power systems that allows a driving convenience. Compared to a manual transmission, however, it has a few problems in efficiency, shift feel, and maintenance. To improve these, it is imperative to understand the dynamics of automatic transmissions. This paper develops a dynamically-correct model of an automatic transmission, using the bond graph method. The bond graph method is ideally suited for modeling power systems, because the method is based on generalized power variables. The bond graph method is capable of providing correct dynamic constraints and kinematic constraints, as well as the governing differential equations of motion. The bond graph method is applied to 1-4 in-gear ranges, as well as various upshifts and downshifts of an automatic transmission, which allows an accurate simulation of an automatic transmission. Conventional automatic transmission models have no dynamic constraint, which do not allow correct simulation studies.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.264-267
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• 2002

This paper proposed a effective priority selection algorithm named weighted round-robin algorithm and show the implementation result of DMAC priority selection module using prosed weighted round-robin algorithm. I parameterize timing constraints of each functional module, which decide the effectiveness of system. Proposed weighted round-robin algorithm decide the most effective module for data transmission using parameterize timing constraints and update timing parameter of each module for next transmission module selection. I implement DMAC priority selection module using this weighted round-robin algorithm and can improve the timing effective for data transmission from memory to functional module or one functional module to another functional module.

• 조명전기설비학회논문지
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• 제23권2호
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• pp.182-189
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• 2009

경쟁적 전력시장에서 발전회사의 전략적 행위를 분석하기 위해서 일반적으로 내쉬균형(Nash equilibrium) 이론이 널리 사용되고 있다. 기존 연구에 의하면 송전제약이 있는 전력시장에서는 최적반응의 불연속으로 인해 순수전략내 쉬균형이 존재하지 않게 되고, 이때는 혼합전략 내쉬균형이 전력시장의 균형이 된다. 본 논문에서는 송전제약이 있는 2-지역 전력시장에서 혼합전략 내쉬균형을 유도하고, 송전용량이 혼합전략 내쉬균형에 미치는 영향을 해석하였다.

• Tribology and Lubricants
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• 제36권2호
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• pp.96-104
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• 2020

The electric vehicle industry is rapidly developing because of enforced environmental regulations, and several studies have been conducted on the multispeed transmission to improve the fuel efficiency of electric vehicles. Among these studies, research on the power density improvement of electric vehicle transmission is critical. Thus, the optimal design of the gear train is necessary to enhance transmission efficiency. In this study, an optimal design methodology for the lightweight two-speed transmission of electric vehicles is proposed. Because a multispeed transmission has many operating conditions and equality and inequality constraints, a new gear design method that combines analytical and iterative methods is applied without using complex optimization algorithms. Sets of possible design variables are generated considering the operating conditions and various design variables. The modules and face width ratios of each stage gear that satisfy the corresponding operating conditions are analytically calculated. The volume of the gear train is calculated, evaluated, and arranged using these values to determine the optimal solution for minimizing the volume, and the proposed methodology is applied to the actual model to verify its effectiveness. The design of a two-speed transmission with multiple operating conditions and constraints without complicated optimization algorithms can be optimized.

• Journal of Electrical Engineering and Technology
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• 제3권3호
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• pp.320-330
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• 2008

This paper presents an improved dynamic programming (IDP) approach to solve the economic power dispatch problem including transmission losses in power systems. A detailed mathematical derivation of recursive dynamic programming approach for the economic power dispatch problem with transmission losses is presented. The transmission losses are augmented with the objective function using price factor. The generalized expression for optimal scheduling of thermal generating units derived in this article can be implemented for the solution of the economic power dispatch problem of a large-scale system. Six-unit, fifteen-unit, and forty-unit sample systems with non-linear characteristics of the generator, such as ramp-rate limits and prohibited operating zones are considered to illustrate the effectiveness of the proposed method. The proposed method results have been compared with the results of genetic algorithm and particle swarm optimization methods reported in the literature. Test results show that the proposed IDP approach can obtain a higher quality solution with better performance.

• 한국기계가공학회지
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• 제11권1호
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• pp.68-75
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• 2012

In this study, the optimal synthesis of planar steering mechanisms for vehicles is studied. The author minimized the steering error between two front wheels subject to the constraints of transmission angles. Nonlinear programming methods such as BFGS method and golden section search method are used for this optimization. As numerical examples, Ackermann's steering mechanism, 6-link and 10-link planar mechanism are adopted to check the usefulness of this method. Consequently, among the three optimized mechanisms, 10-link planar one conducts far more accurate performance subject to tight constraints of transmission angles.

• 전기학회논문지
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• 제57권1호
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• pp.34-39
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• 2008

Nash Equilibrium(NE) is essential to investigate a participant's bidding strategy in a competitive electricity market. Congestion on a transmission line makes it difficult to compute the NE due to causing a mixed strategy. In order to compute the NE of a multi-player game, some heuristics are proposed with concepts of a key player and power transfer distribution factor in other studies. However, generation capacity constraints are not considered and make it more difficult to compute the NE in the heuristics approach. This paper addresses an effect of generation capacity limits on the NE, and suggest a solution technique for the mixed strategy NE including generation capacity constraints as two heuristic rules. It is reported in this paper that a role of the key player who controls congestion in a NE can be transferred to other player depending on the generation capacity of the key player. The suggested heuristic rules are verified to compute the mixed strategy NE with a consideration of generation capacity constraints, and the effect of the generation constraints on the mixed strategy NE is analyzed in simulations of IEEE 30 bus systems.

• 한국콘텐츠학회논문지
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• 제11권1호
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• pp.176-183
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• 2011

이 연구의 목적은 중요무형문화재 무용전승자의 이수제약 요인을 총체적이고 다각적으로 분석하고 극복방안을 제시하는데 있다. 이러한 연구목적을 달성하기 위하여 중요무형문화재 무용분야 3개 단체에서 1개 단체에 2명씩 총 6명의 참여자를 선정하였다. 자료 수집은 심층 면담법을 통해 이루어졌다. 수집된 자료는 분류분석을 실시하였으며, 연구의 진실성을 검증하였다. 결론은 다음과 같다. 첫째, 무용전승자는 가정에서의 이해도, 개인의 체력 문제 등의 개인적 제약을 받는다. 둘째, 무용전승자는 이수시험자격획득까지 걸리는 기간, 연습의 효율성, 전수환경 등의 구조적제약을 받는다. 셋째, 무용전승자는 회원 간의 관계와 보유자와의 관계 등의 대인적 제약을 받는다. 극복방안으로 전국에 소규모의 전수교육장 설립, 객관화된 이수평가 기준의 정립을 통한 이수기간의 현실화, 무용이수교육만이 아닌 화합의 프로그램에 대한 필요성이 제시되었다.

• ETRI Journal
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• 제29권2호
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• pp.201-211
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• 2007

This paper focuses on the scheduling problem with the objective of maximizing system throughput, while guaranteeing long-term quality of service (QoS) constraints for non-realtime data users and short-term QoS constraints for realtime multimedia users in multiclass service high-speed uplink packet access (HSUPA) systems. After studying the feasible rate region for multiclass service HSUPA systems, we formulate this scheduling problem and propose a multi-constraints HSUPA opportunistic scheduling (MHOS) algorithm to solve this problem. The MHOS algorithm selects the optimal subset of users for transmission at each time slot to maximize system throughput, while guaranteeing the different constraints. The selection is made according to channel condition, feasible rate region, and user weights, which are adjusted by stochastic approximation algorithms to guarantee the different QoS constraints at different time scales. Simulation results show that the proposed MHOS algorithm guarantees QoS constraints, and achieves high system throughput.

• Journal of Advanced Marine Engineering and Technology
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• 제33권5호
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• pp.713-720
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• 2009

Numerous applications of position controlling devices using servoing technique and transmission of energy through belt drives are practiced in the industry. Belt drive is a simple, lightweight, low cost power transmission system. Belt drives provide freedom to position the motor relative to the load and this phenomenon enables reduction of the robot arm inertia. It also facilitates quick response when employed in robotics. In this paper, precision positioning of a belt driven mechanism using a feed-forward compensator under maximum acceleration and velocity constraints is proposed. The proposed method plans the desired trajectory and modifies it to compensate delay dynamics and vibration. Being an offline method, the proposed method could be easily and effectively adopted to the existing systems without any modification of the hardware setup. The effectiveness of the proposed method is demonstrated through computer simulation and experimental results.