• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.230-231
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• 2007

계통연계형 태양광 시스템을 구성하고 있는 전력변환장치인 PCS(power conditioning system)는 일반적으로 그 내부에 입력전력 평활용 Capacitor, DC-DC Converter, DC link Capacitor, DC-AC Inverter 및 L-C Filter 등으로 구성된다. 이러한 태양광 시스템의 구성은 주로 태양광 어레이와 PCS의 DC-DC Converter 및 DC-AC Inverter의 수와 연결 방법에 따라 여러 가지로 구성할 수가 있다. 본 논문에서 제안할 시스템의 구성은 하나의 태양광 어레이를 다수의 계통 연계형 태양광 PCS가 공유하는 형태인데, 이러한 시스템의 주요 장점은 첫째, 일사량에 따라 각각의 PCS가 모두 정격에서 운전하도록 하여 변환효율을 개선할 수 있다는 점과 둘째, 태양광 어레이의 용량 확장에 따른 PCS 장치의 용이한 확장성 그리고 셋째, 연결되어 있는 다수의 PCS 중 하나의 태양광 PCS가 고장으로 인하여 유지 및 보수가 필요할 때에도 그 외의 다른 정상적인 태양광 PCS는 지속적인 발전이 가능한 장점 등을 갖는다. 본 논문에서는 태양광 어레이의 출력을 공유하는 병렬운전용 태양광 PCS의 구성에 대하여 연구하고, 그 병렬운전기법을 제시하여 이에 대한 타당성을 시뮬레이션으로 검증하고자 한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.6
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• pp.104-110
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• 2006

In this paper, we proposed the micro web-server implementation on Strong ARM processor with embedded Linux. The parallel port connecting parallel I/O is controlled via HTTP protocol and web browser program HTTP protocol with Linux, the micro web server program and port control program are installed on-board memory using CGI to be accessed by web browser. The processor parallel input port is monitored and parallel output port is controlled from remote hosts via HTTP protocol. The result of the proposed embedded micro-web server can be used in remote automation systems, distributed control via internet using web browser.

• The KIPS Transactions:PartA
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• v.13A no.2 s.99
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• pp.157-162
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• 2006

Recent High Performance Computing (HPC) platforms can be classified as Shared-Memory Multiprocessors (SMP), Massively Parallel Processors (MPP), and Clusters of computing nodes. These platforms are deployed in many scientific and engineering applications which require very high demand on computing power. In order to realize an optimal performance for these applications, it is crucial to find and use the suitable computing platforms and programming paradigms. In this paper, we use SPEC HPC 2002 benchmark suite developed in various parallel programming models (MPI, OpenMP, and hybrid of MPI/OpenMP) to find an optimal computing environments and programming paradigms for them through their performance analyses.

• The Journal of the Korea Contents Association
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• v.7 no.1
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• pp.147-154
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• 2007

In this paper, we propose a new parallel search algorithm to acquire synchronization for UWB(Ultra Wideband) systems that reduces computation of the correlation. The conventional synchronization acquisition algorithms check all the possible signal phases simultaneously using multiple correlators. However it reduces the acquisition time, it makes high power consumption owing to increasing of correlation. The proposed algorithm divides the preamble signal to input the correlator into an m-bit bunch. We check the result of the correlation at first stage of an m-bit bunch data and predict whether it has some synchronization acquisition information or not. Thus, it eliminates the unnecessary operation and save the number of correlation. We evaluate the proposed algorithm under the AWGN and the multi-Path channel model with MATLAB. The proposed parallel search scheme reduces number of the correlation 65% on the AWGN and 20% on the multi-path fading channel.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.6
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• pp.23-37
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• 2004

Since java thread is an object which is treated as independent process within one execution space in the multiprocessing environment, we can use it for independent process of parallel processing. Using thread and synchronization mechanism of java enables us to write parallel application program easily. Therefore, a lot of results are exist which is apply the feature of java that support parallel processing to the distributed computing environment. In this paper, we introduce a system of environment that support parallel execution of thread which is included in legacy java program. The system named TORB(Transparent Object Request Broker) enables us parallel execution of legacy java program after simple converting process, since it support the feature of programming transparency. TORB is extended version of distributed programming tool that is published by our research team. And it had only typical distributed processing feature that is execute a specified function at the specified computer.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.3
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• pp.128-137
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• 2012

In high multistory buildings, hybrid coupled shear walls can provide an efficient structural system to resist horizontal force due to wind and seismic loads. Hybrid coupled shear walls are usually built over the whole height of the building and are laid out either as a series of walls coupled by steel beams with openings to accommodate doors, elevator walls, windows and corridors. In this paper, the behavior characteristics of hybrid coupled shear wall system considering connection details is examined through results of an experimental research program where 5 two-thirds scale specimens were tested under cyclic loading. Such connections details are typically employed in hybrid coupling wall system consisting of steel coupling beams and reinforced concrete shear wall. The test variables of this study are embedment length of steel coupling beam and wall thickness of concrete shear wall. The results and discussion presented in this paper provide fundamental data for seismic behavior of hybrid coupled shear wall systems.

• The Journal of the Acoustical Society of Korea
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• v.40 no.4
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• pp.337-346
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• 2021

Detection of abnormal signal generally can be done by using features of normal signals as main information because of data imbalance. This paper propose an efficient method for abnormal signal detection using parallel AutoEncoder (AE) which can use features of abnormal signals as well. The proposed Parallel AE (PAE) is composed of a normal and an abnormal reconstructors having identical AE structure and train features of normal and abnormal signals, respectively. The PAE can effectively solve the imbalanced data problem by sequentially training normal and abnormal data. For further detection performance improvement, additional binary classifier can be added to the PAE. Through experiments using public acoustic data, we obtain that the proposed PAE shows Area Under Curve (AUC) improvement of minimum 22 % at the expenses of training time increased by 1.31 ~ 1.61 times to the single AE. Furthermore, the PAE shows 93 % AUC improvement in detecting abnormal underwater acoustic signal when pre-trained PAE is transferred to train open underwater acoustic data.

• Database Research
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• v.34 no.3
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• pp.28-44
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• 2018

In a database system, the most expensive operation among relational operations is a join operation. Generally, CPU-based join operations uses parallel processing with either 1 core or 16 cores at most, which does not significantly improve the function. On the other hand, GPGPU(General-Purpose computing on Graphics Processing Units) allows parallel processing through thousands of processing units, greatly reducing the time required to perform join operations. Parallelization of the operation using GPGPU uses NVIDIA's CUDA SDK. In this paper, we implement parallelization of the join operation using GPGPU and compare the performances. The used join operations are Nested Loop Join (NLJ), Sort Merge Join (SMJ) and Hash Join (HJ), and GPGPU equipment uses TITAN Xp, GTX 1080 Ti and GTX 1080. We measure and compare the performance of join operations based on CPU and GPGPU. We compare this performance with the performance of the previous study on the join operation based on GPGPU. The results of experiment show that the performance based on GPGPU is 6~328 times faster than the one based on CPU.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.732-734
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• 1998

본 논문에서는 메시지 전달을 기반으로 하는 병렬 분산 시스템에 고장 감내 기능을 추가하기 위한 고장 감내 기법과, 고장 복구에 따른 프로세서들간의 일관성 유지방법을 제안하였다. 메시지 전달을 기반으로 하는 병렬 컴퓨터 시스템상에서 응용 프로그램들은 수많은 노드들에 분산 배치되어 수행이 되는데, 그중 어느 한 노드 또는 작업 중인 프로세서가 고장을 일으킨다면 이로 인하여 전체 응용 프로그램이 중단 될 것이다. 이러한 문제를 해결하기 위하여 고장 감내 기능 추가가 필요하며, 그 방법으로서 동일한 작업을 수행하는 프로세서를 서로 다른 노드상에 이중화하여 하나의 프로세서에 고장이 발생하더라도 계속 작업중인 예비 프로세서를 이용함으로써 전체 응용 프로그램이 아무런 영향을 받지 않도록 하였다. 그리고 이를 MPI상에 서브 모듈로써 설계하고 구현하였다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.341-344
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• 2007

본 논문에서는 계층적 공정 경쟁 개념을 병렬 유전자 알고리즘에 적용하여 계층적 공정 경쟁 기반 병렬유전자 알고리즘 (Hierarchical Fair Competition Genetic Algorithm: HFCGA)을 구현하였을 뿐만 아니라 실수코딩 유전자 알고리즘(Real-Coded Genetic Algorithm: RCGA)에서 좋은 성능을 갖는 산술교배(Arithmetic crossover), 수정된 단순교배(modified simple crossover) 그리고 UNDX(unimodal normal distribution crossover)등의 다양한 교배연산자들을 적용, 분석함으로써 개선된 병렬 유전자 알고리즘을 제안하였다. UNDX연산자는 다수의 부모(multiple parents)를 이용하여 부모들의 기하학적 중심(geometric center)에 근접하게 정규분포를 이루며 생성된다. 본 논문은 UNDX를 이용한 HFCGA모델을 구현하고 함수파라미터 최적화 문제에 많이 쓰이는 함수들에 적용시킴으로써 그 성능의 우수성을 증명 한다.