• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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• pp.583-586
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• 2003

There are electric four-wheeled vehicles to assist elder people. Because of the vehicles'dynamic characteristic such as impossible to move abeam, it is difficult for these people who has little experience and has little knowledge to drive. Also to judge the future state of dynamic obstacles and to decide how to elude them safely are more difficult. We installed the predictive fuzzy controller(evaluates the future states which several kinds of operation candidates were done and chooses the best one) that modeled humans'algorithms in the system. Human predicts the future states of dynamic obstacles and chooses an operation(wait, steer, go back, etc) to elude safely. To elude dynamic obstacles flexibly, we added expert's knowledge for safe driving to this controller. In this paper, we propose the intelligent soft driving system by the controller that can elude dynamic obstacles safely, and we confirm the effectiveness by a simulation.

• 한국자동차공학회논문집
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• 제3권1호
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• pp.108-117
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• 1995

The primary purpose of this extensive test effort was to observe real-time operational performance characteristics associated with automotive grade fuel utilized by piston engine powered light aviation aircraft. In fulfillment of this effort, baseline engine operations were established with 100LL aviation grade fuel followed by four blends of automotive grade fuel. A comprehensive sea-level-static test cell/flight test data collection and evaluation effort were conducted to review operational characteristics of a carbureted light aircraft piston engine as related to fuel volatility, fuel temperature, and fuel system pressure. Presented herein are results, data, and conclusions drawn from test cell engine operation as well as flight test operation on 100LL aviation grade and four blends of automotive grade fuel.

• 한국항해학회지
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• 제23권1호
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• pp.1-13
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• 1999

Ship system can be divided into four sub-systems: hull, propeller, main engine and operation system which severely affect the characteristics of a ship. In determining ship speed in waves, two factors are considered the involuntary speed loss due to added resistance caused by wind and waves, and the voluntary speed loss by command of operation system to prevent severe ship motions. In this paper, the main function of four sub-system is analyzed for input/output relations and propulsive coefficient and a useful method to predict involuntary speed loss of a ship is presented. Two calculated examples for a high speed container ship and a passenger ship with single screw and diesel engine are given.

• 전력전자학회논문지
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• 제8권3호
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• pp.285-291
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• 2003

스위치드 릴럭턴스 전동기는 고출력, 고효율 및 직권전동기 구동특성 등으로 견인구동용으로 주목받고 있다. 그러나 전동기를 4상한 구동하기 위한 발전영역에서 제어는 쉽지 않다. 본 논문은 전류제한법에 의해 안정된 발전제동이 가능한 제어방식을 제안하였다. 전동기 구동시는 기준전류제한방식과 위상각 제어방식으로 속도제어를 행하고, 발전제동모드에서는 상전류가 발산하지 않는 조건을 산정하여서 이 값을 기준전류로 한 전류제한방식을 채택하였다. 시뮬레이션과 실험에 의해 제안한 방식의 타당성을 확인하였다.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1996년도 추계학술대회발표논문집; 고려대학교, 서울; 26 Oct. 1996
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• pp.303-306
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• 1996

This paper proposes a heuristic method for job shop scheduling with alternative machines. Our heuristic suggests four machine-selecting rules and two priority dispatching rules for modifying existent ones considering alternative machines, and then it extends existing nondelay/active job shop schedule generation. This heuristic provides good criteria(rules) in the selection of a proper machine among those performing a specific operation and for the dispatch of an operation to a selected machine and thus these rules permit the efficient job shop scheduling with alternative machines. The performances of our four machine-selecting rules in addition to the two priority dispatching rules, applied together with the existing 17 rules, are experimented and evaluated, respectively.

• 대한인간공학회지
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• 제13권2호
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• pp.65-79
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• 1994

A biomechanical model of lower extremity in seated postures was developed to assess muscular activities of lower extremity involved in a variety of foot pedal operations. The model incorporated four rigid body segments with the twenty-four muscles to represent lower extremity. This study deals with quasi-static movement to investigate dymanic movement effect in seated foot operation. It is found that optimization method which has been used for modeling the articulated body segments does not predict the forces generated from biarticular muscles and antagonistic muscles reasonably. So, the revised nonlinear optimization scheme was employed to consider the synergistic effects of biarticular muscles and the antagonistic muscle effects from the stabilization of the joint. For the model validation, three male subjects performen the experiments in which EMG activities of the nine lower extremity muscles were measured. Predicted muscle forces were compared with the corresponding EMG amplitudes and it showed no statistical difference. For the selection of optimal seated posture, a physiological meaningful criterion for muscular load sharing developed.

• ETRI Journal
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• 제20권4호
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• pp.380-394
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• 1998

A numerical study has been performed to predict the characteristics on the transient operation of the heat pipe with multiple heaters for electronic cooling. The model of the heat pipe was composed of the evaporator section with four heaters, insulated transport section, and the condensor section with a conductor which is cooled with uniform heat flux condition to surrounding. The governing equations and the boundary conditions were solved by the generalized PHOENICS computational code employing the finite volume method. Two test cases are investigated in present study; Case 1 indicates that the 1st and 2nd heaters among four heating sources are heated off, while the 3rd and 4th heaters are heated on. Case 2 is the inverse situation switched from heating location of Case 1. The results show that the transient time to reach the steady state is shorter for Case 1 than for Case 2. Especially, the temperature difference of the heater during switching operation is relatively small compared to the maximum allowable operating temperature difference in electronic system. Hence, it is predicted that the heat pipe in present study operates with thermally good reliability even for switching the heaters.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1626-1632
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• 2007

Power Car PC1 and PC2 of Korean high speed train have a auxiliary block which consists of two PWM converter respectively. If a auxiliary block happens a critical failure, the other supplies power to full load of train. In this case, a stability of auxiliary block reduces by a increasing load. For increasing a stability of auxiliary block and train system, a auxiliary block consists of two group four PWM converter which operates simultaneously. If a group of a auxiliary block happens a critical failure, the other supplies power to load of a auxiliary block. This paper describes a method for simultaneous movement of auxiliary block which consists of two group four PWM converter.

• 공학교육연구
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• 제18권6호
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• pp.38-45
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• 2015

This study aims to conduct a case study of the Science, Technology, Engineering, Arts, and Mathematics (STEAM) outreach program development and their application. This program was operated by 184 middle and high school students at C University on October 2014. The major results of these studies were as follows: First, The theme of the outreach program consisted of four engineering areas, aerospace engineering, chemical engineering, architectural engineering, and mechatronics (robot) engineering; moreover, the materials for the students' workbook, the guidebook for teachers, and the program operation manual for staffs in a university were developed by working with four authors and ten subject matter experts. Second, the satisfaction level with the contents and activities was ranged from 4.24-4.31 out of 5 points. Third, the vitalizing activation plan was discussed for the sustainable development and operation of the STEAM outreach program.

• Journal of Power Electronics
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• 제9권2호
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• pp.146-155
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• 2009

The static frequency converter (SFC) systems are used as a method of driving large synchronous machines in many power and industrial plants. In this paper, new control algorithms of SFC systems for starting gas turbo sets are proposed for a four quadrant operation: start-up at standstill; an acceleration up to the speed of the rated voltage; field weakening to reach the rated speed; synchronization to the main alternating current (AC) source; and dynamic braking to stop safely within the rating of the synchronous machine. Experimental results show that the proposed algorithms are proper and effective.