• Journal of Information Processing Systems
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• 제6권1호
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• pp.21-32
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• 2010

Software maintenance is one of the major activities of the software development life cycle. Due to the time and cost constraint it is not possible to perform exhaustive regression testing. Thus, there is a need for a technique that selects and prioritizes the effective and important test cases so that the testing effort is reduced. In an analogous study we have proposed a new variable based algorithm that works on variables using the hybrid technique. However, in the real world the programs consist of multiple modules. Hence, in this work we propose a regression testing algorithm that works on interprocedural programs. In order to validate and analyze this technique we have used various programs. The result shows that the performance and accuracy of this technique is very high.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2016년도 학술발표회
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• pp.192-192
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• 2016

Nowadays, stormwaters have been affected by urbanization and climate change. These transition can cause many problems for hydrologic cycle by increasing runoff volume like flood and low water quality. As with other metropolises and peninsulas, Busan has involved with these problems too. Therefore, it is really vital to do some arrangements to solve them by low impact development (LID) technology. In fact, LID has been introduced to reduce runoff by applying some techniques such as green infrastructure (GI). In order to deal with the aforementioned issues in Busan, this study attempts to design and construct a hybrid green roof-planter box system at Pusan National University GI/LID Facility based on local weather. For this purpose, we used experiment and modeling method on some planter boxes and optimized them by trial and error method.

• 한국정보통신학회논문지
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• 제23권12호
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• pp.1734-1737
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• 2019

This paper presents a prediction structure with a Hybrid Dynamic Branch Prediction (HDBP) scheme which decreases the number of stalls. In the application, a branch history register is dynamically adjusted to produce more unique index values of pattern history table (PHT). The number of stalls is also reduced by using the modified gshare predictor with a long history register folding scheme. The aliasing rate decreased to 44.1% and the miss prediction rate decreased to 19.06% on average compared with the gshare branch predictor, one of the most popular two-level branch predictors. Moreover, Compared with the gshare, an average improvement of 1.28% instructions per cycle (IPC) was achieved. Thus, with regard to the accuracy of branch prediction, the HDBP is remarkably useful in boosting the overall performance of the superscalar processor.

• 한국자동차공학회논문집
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• 제13권3호
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• pp.35-40
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• 2005

In the present study, the influence of operating conditions on fuel economy for hybrid electric vehicle was analyzed. In order to accomplish this, vehicle speed, engine speed, battery current and voltage, SOC (state of charge),motor speed and torque, generator speed and torque, engine coolant temperature etc. were measured in real time. The tests were carried out under different driving cycles which are urban and highway cycles, KOREA CITY cycle and on-road driving, and also under various operating conditions such as different initial SOC, with or without regenerative braking etc.. Generally, conventional gasoline engines show a poor fuel economy at stop and go driving, because braking energy is wasted and the engine is operated in low thermal efficiency regions. However, in case of hybrid vehicles, higher fuel economy can be obtained because of utilizing the maximum thermal efficiency regions of engine, idling stop of engine, and regenerative braking etc..

• 전기화학회지
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• 제6권2호
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• pp.153-157
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• 2003

전기이중층 축전용량(electric double layer capacitance)과 유사축전용량(pseudo-capacitance)을 함께 갖는 하이브리드 전기화학 축전기에 대한 연구를 수행하였다. 양극은 $Ni(OH)_2$ 활성탄소가 복합된 전극을 사용하였으며 음극은 활성탄소를 활물질로 사용하므로써 비대칭 전극 구조를 갖는다. 셀 실험을 위하여 $5\times5cm^2$ 크기인 전극을 제작 사용하였다. Cyclic voltammetry측정 및 교류 임피던스 측정실험을 통하여 각각의 셀들이 갖는 전기화학적 거동을 조사하였고 충 방전 실험을 통하여 양극과 음극의 최적 질량비를 조사하였다.

• 한국수소및신에너지학회논문집
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• 제28권1호
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• pp.30-39
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• 2017

Interests in fuel cell based power generation systems are on the steady rise owing to various advantages such as high efficiency, ultra low emission, and potential to achieve a very high efficiency by a synergistic combination with conventional heat engines. In this study, the performance of a hybrid system which combined a molten carbonate fuel cell (MCFC) and an indirectly fired micro gas turbine adopting carbon dioxide capture technologies was predicted. Commercialized 2.5 MW class MCFC system was used as the based system so that the result of this study could reflect practicality. Three types of ambient pressure hybrid systems were devised: one adopting post-combustion capture and two adopting oxy-combustion capture. One of the oxy-combustion based system is configured as a semi-closed type, while the other is an open cycle type. The post-combustion based system exhibited higher net power output and efficiency than the oxy-combustion based systems. However, the semi-closed system using oxy-combustion has the advantage of capturing almost all carbon dioxide.

• 한국철도학회논문집
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• 제12권1호
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• pp.122-128
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• 2009

바이모달 수송시스템 연구단에서 개발중인 트램은 자동운전이 가능하고 일반도로와 전용구간을 주행할 수 있는 고무차륜방식의 저상굴절 바이모달 트램으로서, 압축천연가스 엔진과 리튬폴리머 배터리를 사용하는 직렬형 하이 브리드 추진계로 구동된다. 본 논문에서는 바이모달 트램의 직렬형 하이브리드 추진장치의 요구사양을 제시하고 하이브리드 추진제어방식에 관해 설명한다. 하이브리드 차량 시뮬레이션 툴인 ADVISOR를 사용하여 기준 주행사이클과 일본의 10-15 mode에 대한 바이모달 트램의 주행을 모의하고, CNG 하이브리드 추진계에 대한 성능을 분석한다.

• 한국CDE학회논문집
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• 제11권2호
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• pp.77-87
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• 2006

It is necessary to change the existing design process to cope with a short life-cycle product and various customer's demands. Also a frequent design change may delay the whole design process and it will increase the unit cost of the production. New alternatives or techniques have emerged to solve the existing design problems, such as a knowledge based engineering, an intelligent CAD, a function based design, and so on. In this paper, we propose a hybrid design system with a knowledge based design methodology and a function based design technique. The knowledge based design is good at a frequent design change and the function based design is effective to extract a core design behavior. In an early design process, the system utilizes a core design behavior through the function based design process. On the other hand, the system manages complicated design issues with the knowledge based design technique in the detailed design process. We conclude that the hybrid design system can bring fair effects on implementing an efficient design environment in aspect of time and expense.

• 한국생산제조학회지
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• 제24권5호
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• pp.576-582
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• 2015

Generally, the fuel economy of hybrid electric vehicle (HEV) is effected by the size of each component. In this study the fuel economy for HEV of our own making is evaluated using backward simulator, where dynamic programming is applied. In a competition, the vehicle is running through the road course that includes many speed bumps and steep grade. Therefore, the new driving cycle including road grade is developed for the simulation. The backward simulator is also developed through modeling each component. A performance map of engine and motor for component sizing is made from the existing engine map and motor map adapted to the HEV of our own making. For optimal component sizing, the feasible region is defined by restricting the power range of power sources. Optimal component size for best fuel economy is obtained within the feasible region through the backward simulation.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1102-1106
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• 2015

A hybrid supercapacitor (HS) is an energy storage device used to enhance the low weight energy density (Wh/kg) of a supercapacitor. On the other hand, a sudden decrease in capacity has been pointed out as a reliability problem after many charge/discharge cycles. The reliability problem of a HS affects the early aging process. In this study, the capacity performance of a HS was observed after charge/discharge. For detailed analysis of the initial charge/discharge cycles, the charge and discharge curve was measured at a low current density. In addition, a solid electrolyte interphase (SEI) layer was confirmed after the charge/discharge. A HC composed of a lithium titanate (LTO) anode and active carbon cathode was used. The charge/discharge efficiency of the first cycle was lower than the late cycles and the charge/discharge rate was also lower. This behavior was induced by SEI layer formation, which consumed Li ions in the LTO lattice. The formation of a SEI layer after the charge/discharge cycles was confirmed using a range of analysis techniques.