• 전력전자학회논문지
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• 제10권1호
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• pp.45-51
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• 2005

본 논문에서는 서치코일이 장착된 SRM(Switched Reluctance Motor)의 정지시 회전자 위치를 추정하는 방법을 비교하여 제시하였다. 서치코일이 장착된 SRM은 초기에 정지상태이므로 서치코일에서 유기기전력이 발생하지 않는다. 따라서 정지상태에서 회전자의 위치를 검출하기 위한 방법이 필요하게 된다. 본 논문에서는 유클리디안 제곱거리, 퍼지, 신경망 등 세 가지 방법을 이용하여 회전자의 위치 추정을 위한 시뮬레이션을 실행하였고 그 결과를 비교하였다. 또한 시뮬레이션 결과가 우수한 유클리디안 제곱거리를 이용하여 회전자 위치 추정을 위한 실험을 실시하여 본 논문에서 제안한 방법의 타당성을 검증하였다.

• 정보관리연구
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• 제37권4호
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• pp.25-47
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• 2006

다국어로 구축된 학술정보 시스템의 통합검색 환경을 구현하기 위해서는 다국어 전문용어에 대한 해석을 제공하고 전문용어의 분야별 분류정보를 제공할 수 있는 시스템이 필요하다. 본 연구는 이러한 다국어 환경의 통합 정보검색 시스템을 운용할 수 있도록 기반시스템을 구축하는 것을 목적으로 한다. 다국어 의미망으로 상호 연결된 과학기술 전문용어 체계를 구축하는 방법과 다단계 연결노드에 대한 최단거리 탐색 기법을 소개하였다. 또한, 생성된 용어군집 결과를 해석하기 위한 기초분석을 수행하여 향후 심도있는 분석연구를 수행하기 위한 기반을 마련하고자 하였다.

• International Journal of Computer Science & Network Security
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• 제21권8호
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• pp.87-96
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• 2021

The demand for e-learning through video lectures is rapidly increasing due to its diverse advantages over the traditional learning methods. This led to massive volumes of web-based lecture videos. Indexing and retrieval of a lecture video or a lecture video topic has thus proved to be an exceptionally challenging problem. Many techniques listed by literature were either visual or audio based, but not both. Since the effects of both the visual and audio components are equally important for the content-based indexing and retrieval, the current work is focused on both these components. A framework for automatic topic-based indexing and search depending on the innate content of the lecture videos is presented. The text from the slides is extracted using the proposed Merged Bounding Box (MBB) text detector. The audio component text extraction is done using Google Speech Recognition (GSR) technology. This hybrid approach generates the indexing keywords from the merged transcripts of both the video and audio component extractors. The search within the indexed documents is optimized based on the Naïve Bayes (NB) Classification and K-Means Clustering models. This optimized search retrieves results by searching only the relevant document cluster in the predefined categories and not the whole lecture video corpus. The work is carried out on the dataset generated by assigning categories to the lecture video transcripts gathered from e-learning portals. The performance of search is assessed based on the accuracy and time taken. Further the improved accuracy of the proposed indexing technique is compared with the accepted chain indexing technique.

• International Journal of Computer Science & Network Security
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• 제21권7호
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• pp.273-283
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• 2021

The aim of this paper is to review the current knowledge management (KM) practices and their importance in the public sector of Saudi Arabia. Using the term "knowledge management in public sector", a search for available works was done in Google Scholar. In the first stage, the search for literature published under anytime choice was done in the first 10 pages of the search engine. Then another nine pages of Goggle Scholar were searched for more recent works published setting the time as 2014 to 2018. The search yielded 37 usable works for this review. The results of this literature search and review indicated that out of the 37 works reviewed, only three works were related to Saudi Arabia. Number of papers on factors of KM were maximum, many of them giving diagrammatic presentation of their results. KM modelling itself is not easy as only very few papers on KM modelling were available. Problems of too much reliance on qualitative data and hypotheses not matching with the literature backgrounds for them were also found. Considering the works related to KM, the number of papers in various categories may indicate the dimensions of KM to be considered when KM is implemented or evaluated in any public sector of any country. This applies to Saudi Arabian public sector organizations also. There is a fertile ground of research waiting to be investigated by researchers in Saudi Arabia.

• 인터넷정보학회논문지
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• 제18권4호
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• pp.109-119
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• 2017

본 연구는 온라인검색광고 기반의 사업모델을 가진 대표적인 포털사업자 네이버의 광고관리시스템이 제공하는 데이터를 이용하여 온라인검색광고시장이 양면시장이 아닐 수 있음을 실증분석하고 이를 근거로 한 적절한 동 시장의 시장획정 방안 제시를 목적으로 한다. 이 목적을 위해 두 가지 연구 질문에 대한 검토가 필요하다. 첫째, 온라인검색광고 사업모델과 학문적 의의가 큰 로체-티롤의 양면시장 정의 간에 일관성이 있는가, 둘째, 온라인검색광고시장에 간접네트워크외부효과가 존재하는가이다. 특히 후자의 경우 간접네트워크외부효과가 있다면 어느 정도인지 실증분석을 수행하여야 한다. 이에 대해 본 연구는 구글과 같은 온라인검색광고서비스가 단면시장일 수 있다는 Luchetta의 이론적 주장에 기반을 두고 이를 검증하기 위해 상관 및 회귀분석을 수행하였다. 온라인검색 광고비는 직접네트워크외부효과 독립변수인 광고주가 한 단위 증가할 때 약 50원 이상 증가하였다. 그러나 간접네트워크외부효과 측정을 위해 설정한 독립변수인 검색횟수와 종속변수인 온라인검색광고비 간에는 유의적인 상관 및 회귀결과가 나타나지 않았다. 이 결과에 따르면, 온라인검색광고시장에는 양면시장의 필요조건인 간접네트워크외부효과가 존재하지 않거나 유의적이지 않아 양면시장이라기 보다는 단면시장일 가능성이 높다. 이는 온라인검색광고시장에 전통적인 시장획정 방법을 적용할 수 있고, 본원적인 경쟁요소를 모색하는데 유리하며, 경쟁상황에 대한 설명력이 높아짐을 의미한다. 또한 양면시장에 대한 시각차를 보여 온 경제학자들과 규제실무자를 포함한 법학자들의 간극도 어느 정도 극복할 수 있다는 점에서 의의가 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1982-1985
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• 2003

Future cellular networks will mainly be driven by, high quality channels, high band with utilization, low power consumption and efficient network management. For a given channel allocation, the capacity and quality of communication of cellular radio systems using CDMA(Code Division Multiple Access) can be increased by using a transmitter power control scheme to combat the near-far problem. Centralized power control schemes or distributed ones to maximize the minimum signal-to-interference in each user of CDMA wireless network have been investigated. This paper has proposed a distributed power control algorithm, which employs an adaptive search scheme, in order to solve quickly the linear systems of equations for power update in CDMA cellular radio systems. The simulation results show that the proposed scheme has faster convergence rate than the typical bang-bang type of distributed power control algorithm, which has been much used as a reference algorithm in IS-95A and W-CDMA communication network.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2006년도 춘계공동학술대회 논문집
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• pp.1609-1615
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• 2006

Overlay multicast technique is an effective way as an alternative to IP multicast. Traditional IP multicast is not widely deployed because of the complexity of IP multicast technology and lack of application. But overlay multicast can be easily deployed by effectively reducing complexity of network routers. Because overlay multicast resides on top of densely connected IP network, In case of multimedia streaming service over overlay multicast tree, real-time data is sensitive to end-to-end delay. Therefore, moderate algorithm's development to this network environment is very important. In this paper, we are interested in minimizing maximum end-to-end delay in overlay multicast tree. The problem is formulated as a degree-bounded minimum delay spanning tree, which is a problem well-known as NP-hard. We develop tabu search heuristic with intensification and diversification strategies. Robust experimental results show that is comparable to the optimal solution and applicable in real time

• 한국경영과학회지
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• 제36권2호
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• pp.1-14
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• 2011

In this paper, we deal with an access network design problem of fiber-to-the-home passive optical network (FTTH-PON). The FTTH-PON network design problem seeks to minimize the total cost of optical splitters and cables that provide optical connectivity between central office and subscribers. We develop a flow-based mixed integer programming (MIP) model with nonlinear link cost. By developing valid inequalities and preprocessing rules, we enhance the strength of the proposed MIP model in generating tight lower bounds for the problem. We develop an effective Tabu Search (TS) heuristic algorithm that provides good quality feasible solutions to the problem. Computational results demonstrate that the valid inequalities and preprocessing rules are effective for improving the LP-relaxation lower bound and TS algorithm finds good quality solutions within reasonable time bounds.

• 한국경영과학회지
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• 제30권1호
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• pp.1-15
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• 2005

In this paper, we deal with a mesh network design problem arising from the deployment of WDM for the optical internet. The mesh network consists of mesh topology for satisfying traffic demand while minimizing the cost of WDM, OXC, and fiber cables. The problem seeks to find an optimal routing of traffic demands in the network such that the total cost is minimized. We formulate the problem as a mixed-integer programming model and devise a tabu search heuristic procedure. Also we develop an optical internet design system that implements the proposed tabu search heuristic procedure. We demonstrate the computational efficacy of the proposed algorithm, compared with CPLEX 8.0.

• 산업공학
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• 제18권4호
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• pp.504-511
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• 2005

The NP-hard channel assignment problem becomes more and more important to use channels as efficiently as possible because there is a rapidly growing demand and the number of usable channel is very limited. The hybrid genetic and local search (HGLS) method in this paper is a hybrid method of genetic algorithm with no interference channel assignment (NICA) in clustering stage for diversified search and local search in tuning stage when the step of search is near convergence for minimizing blocking calls. The new representation of solution is also proposed for effective search and computation for channel assignment.