• 한국정밀공학회지
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• 제25권9호
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• pp.59-70
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• 2008

Polynomial is used to optimize crown bowl shape of a marine medium speed diesel engine piston. The primary goal of this paper is that it's for an original design through a thermal stress and highest temperature minimum. Piston is modeled using solid element with 6 design variables defined the positional coordinate value. Global optimum of design variables are found and evaluated as developed and integrated with the optimum algorithm combining genetic algorithm(GA) and tabu search(TS). Iteration for optimization is performed based on the result of finite element analysis. After optimization, thermal stress and highest temperature reduced 0.68% and 1.42% more than initial geometry.

• Journal of Electrical Engineering and Technology
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• 제10권2호
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• pp.529-538
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• 2015

Due to the high efficiency and compact mechanical structure, direct drive variable speed generators are used for power conversion in wind turbines. The wind energy conversion system (WECS) considered in this paper consists of a permanent magnet synchronous generator (PMSG), uncontrolled rectifier, dc-dc boost converter controlled with maximum power point tracking (MPPT) and adaptive hysteresis controlled voltage source inverter (VSI). For high utilization of the converter's power capability and stabilizing voltage and power flow, constant DC-link voltage is essential. Step and search MPPT algorithm which senses the rectified voltage ($V_{DC}$) alone and controls the same is used to effectively maximize the output power. The adaptive hysteresis band current control is characterized by fast dynamic response and constant switching frequency. With MPPT and adaptive hysteresis band current control in VSI, the DC link voltage is maintained constant under variable wind speeds and transient grid currents respectively.

• 전자공학회논문지A
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• 제33A권5호
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• pp.172-179
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• 1996

In the paper, QCELP (qualcomm code excited linear predictive), CDMA (code division multiple access)'s vocoder algorithm, was analyzed. And then, a ptich parameter seaarch architecture for 16-bit programmable DSP(digital signal processor) for QCELP was designed. Because we speed up the parameter search through high speed DSP using two MACs, we can satisfy speech codec specifiction for the digital celluar. Also, we implemented in FIFO(first-in first-out) memory using register file to increase the access time of data. This DSP was designed using COMPASS, ASIC design tool, by top-down design methodology. Therefore, it is possible to cope with rapid change at mobile communication market.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.698-702
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• 2001

This paper presents a combinatorial method to compute the solutions of optimization problem. The present hybrid algorithm is the synthesis of an artificial life algorithm and the random tabu search method. The hybrid algorithm is not only faster than the conventional artificial life algorithm, but also gives a more accurate solution. In addition, this algorithm can find all global optimum solutions. And the enhanced artificial life algorithm is applied to optimum design of high-speed, short journal bearings and the usefuless is verified through this example.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권3호
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• pp.1091-1110
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• 2016

Hybrid deployment under current cloud data centers is a combination of online and offline services, which improves the utilization of the cluster resources. However, the performance of the cluster is often affected by the online services in the hybrid deployment environment. To improve the response time of online service (e.g. search engine), an effective scheduling algorithm based on Storm is proposed. At the component level, the algorithm dispatches the component with more influence to the optimal performance node. Inside the component, a reasonable resource allocation strategy is used. By searching the compressed index first and then filtering the complete index, the execution speed of the component is improved with similar accuracy. Experiments show that our algorithm can guarantee search accuracy of 95.94%, while increasing the response speed by 68.03%.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.228-231
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• 2008

For a satellite data communication, the technology of frame synchronization is widely used between a sender and a receiver. Last year, we suggested zero-loss frame synchronization [1] using pattern search and using bits threshold search algorithm that is based on SIMD technology [2,3]. This algorithm could solve both of hardware and software drawbacks, which are frame loss and low processing performance. However, this algorithm didn't optimize the processing of output data, synchronized data, which caused overhead to the memory allocation and the memory copy. Consequently, the performance of the frame synchronizer application was degraded. In this paper, we enhance previous work using a circular buffer in order to optimize the output data processing. The performance comparison with the previous algorithm shows that the enhanced proposed approach dramatically outperforms in the output data processing speed.

• 소음진동
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• 제5권2호
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• pp.183-195
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• 1995

The mathematical model of the gear reductioner which consists which consists of the geared rotor-bearing system containing case is developed, assuming as the lumped parameter system. Constraints for vibration suppresion as well as strength of gear teeth, and shaft and kinematic conditions in gear pairs are considered. To find the design parameters satisfing the proposed constraints, a direct search method modified by the technique of Taguchi's experimental scheduling is used. One and two stepped gear reductioners are designed so that the criticl speeds due to the gear transmission error are moved out of the operating speed range.

• 한국통신학회논문지
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• 제21권7호
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• pp.1716-1725
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• 1996

In this paper, the huffman decoder which is a part of the decoder in JPEG standard format is designed by using a new Ternary CAM. First, the 256 word * 16 bit-size new bit-word all parallel Ternary CAM system is designed and verified using SPICE and CADENCE Verilog-XL, and then the verified novel Ternary CAM is applied to the new huffman decoder architecture of JPEG. So the performnce of the designed CAM cell and it's block is verified. The new Ternary CAM has various applications because it has search data mask and storing data mask function, which enable bit-wise search and don't care state storing. When the CAM is used for huffman look-up table in huffman decoder, the CAM is partitioned according to the decoding symbol frequency. The scheme of partitioning CAM for huffman table overcomes the drawbacks of all-parallel CAM with much power and load. So operation speed and power consumption are improved.

• 조명전기설비학회논문지
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• 제24권10호
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• pp.149-156
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• 2010

In this paper, the optimal design of a wind generator, implemented with the hybridized GA(Genetic Algorithm) and ES(Expert System), has been performed to maximize the AEP(Annual Energy Production) over the whole wind speed characterized by the statistical model of wind speed distribution. In particular, to solve the problem of calculation iterate, ES finds the superior individual and apply to initial generation of GA and it makes reduction of search domain. Meanwhile, for effective searching in reduced search domain, it propose Intelligent GA algorithm. Also, it shows the results of optimized model 500[kW] wind generator using hybridized algorithm and benchmark result of compare with GA.

• 한국비블리아학회지
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• 제22권1호
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• pp.281-299
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• 2011

최근 도서관은 웹기술을 이용하여 이용자들의 참여와 만족을 이끌어 내는데 노력하고 있다. 이 연구는 Open API 기술을 활용하여 다양한 정보원들을 검색할 수 있게 한 D대학 도서관시스템에 대하여 이용자 만족도를 평가하였다. 이를 위하여 90명의 학생들에게 시사적 주제 2개와 학업관련 주제 2개를 가지고 검색하게 한 후, 홈페이지의 통합검색 기능 및 연계기능에 대한 만족도와 연계된 콘텐츠에 대한 만족도를 측정하였다. 그 결과 학생들은 대체적으로 만족하고 있었으며 검색기능의 용이성과 미리보기의 유용성 면에서 가장 높은 만족을 보인 반면 디스플레이 방식에 대해서는 불만족하고 있음을 알 수 있었다. 특히 사진자료보기 및 동영상보기, 검색결과의 배열 및 브라우징, 검색결과의 양과 검색속도에 대한 낮은 만족도를 보였다. 또한 콘텐츠를 최신성, 적합성, 유용성, 활용성면에서 평가한 결과가 지식인, 도서관 소장자료, 학위논문/학술지, 이미지자료 순으로 만족하였다. 검색확장에 대한 불만족 사항은 유용성이 높은 검색 인터페이스를 구축함으로써 개선될 수 있을 것으로 본다.