• 대한전기학회논문지:전력기술부문A
• /
• 제50권11호
• /
• pp.528-536
• /
• 2001

This paper proposes a method of solving a unit commitment problem using parallel tabu search(PTS) approach. Tabu search is a heuristic optimization method that has the tabu list to control the search process. To improve the searching ability of a global solution, we used a method of exchanging solutions among connected processors as a diversification strategy, and to reduce the computation time, a new evaluating method was proposed which evaluates only a changed par. To show the usefulness of the proposed method, we simulated for 10 units system and 110 units system. Numerical results show improvements in the generation costs and the computation time compared with other conventional methods.

• Journal of Information Technology Applications and Management
• /
• 제13권2호
• /
• pp.55-65
• /
• 2006

Since the World-Wide Web (WWW) has become a major channel for information delivery, information overload also has become a serious problem to the Internet users. Therefore, effective information searching is critical to the success of Internet services. We present an integrated search engine for searching relevant web pages on the WWW in a certain Internet domain. It supports a local search on the web sites. The spider obtains all of the web pages from the web sites through web links. It operates autonomously without any human supervision. We developed state transition diagram to control navigation and analyze link structure of each web site. We have implemented an integrated local search engine and it shows that a higher satisfaction is obtained. From the user evaluation, we also find that higher precision is obtained.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
• /
• pp.488-491
• /
• 1995

The paper presents a new global maximum search method for multimodal unknown functions of two variables. The search method is composed of two stages and sequentially samples the candidate point in a subdomain selected using a priority function in each stage. The search domain is auto-similarly divided into triangular subdomains, or cells, during the search process. A measure of accuracy of local maximum search is introduced to check if a local search has converged to a specified accuracy or the maximum of a local peak cannot be the global maximum. A criterion for switching from the first to the second stage, is proposed using a ratio of the observed peak width to the largest cell in the domain. By numerical simulations, the required number of trials is evaluated for some function models with different peak parameters, and the switching criterion is optimally determined. The results show that the proposed method obtains global maximum points with certainty and saves largely computation time even for functions with extremely steep peaks.

• East Asian Economic Review
• /
• 제21권2호
• /
• pp.147-165
• /
• 2017

This study quantifies the dynamic interrelationship between the KOSPI index return and search query data derived from the Naver DataLab. The empirical estimation using a bivariate GARCH model reveals that negative contemporaneous correlations between the stock return and the search frequency prevail during the sample period. Meanwhile, the search frequency has a negative association with the one-week- ahead stock return but not vice versa. In addition to identifying dynamic correlations, the paper also aims to serve as a test bed in which the existence of profitable trading strategies based on big data is explored. Specifically, the strategy interpreting the heightened investor attention as a negative signal for future returns appears to have been superior to the benchmark strategy in terms of the expected utility over wealth. This paper also demonstrates that the big data-based option trading strategy might be able to beat the market under certain conditions. These results highlight the possibility of big data as a potential source-which has been left largely untapped-for establishing profitable trading strategies as well as developing insights on stock market dynamics.

• 한국비블리아학회지
• /
• 제13권1호
• /
• pp.5-25
• /
• 2002

본 논문에서는 경쟁정보에 대한 문헌정보학적인 접근에 동기를 부여하고 이를 교육에 적극적으로 수용하는데 도움이 되고자 경쟁정보의 연구에 필요한 기초 정보원에 대한 소개와 함께 경쟁정보에 관련된 정보원의 현황을 살펴보고자 한다. 따라서 몇 가지 관련 이슈들인 1) 경쟁정보의 개념, 2) 경쟁정보과정, 3) 경쟁정보를 위한 인터넷 사용, 4) 경쟁정보를 제공하는 정보원을 다루고자 한다. 다양한 도구를 사용하여 경쟁정보에 대한 탐색결과, 아직은 외국과 비교하여 경쟁정보에 관한 국내 정보원들은 많지 않았다. 부록을 통해서 경쟁정보에 관한 국내외 정보원을 포함한 정보길잡이를 제공한다.

• 지식경영연구
• /
• 제16권4호
• /
• pp.1-16
• /
• 2015

This paper aims to explore the small and medium sized enterprises'(SMEs') technological innovation through an open innovative strategy. Researchers have identified open innovation as external search 'breadth' and 'depth'. Although an open innovation strategy is well known as an effective way for SMEs' innovation, this stream of research examines differences between pursuing breadth of external knowledge and depth of external knowledge for SEMs' innovation. The sample comprises a total of 1106 SMEs included in the Korean Innovation Survey, and logistic regression analysis and odds ratio comparison were used to evaluate the relationship between external knowledge search and innovation outcomes. The results show that both 'breadth' and 'depth' positively affect the SMEs' innovation. When SMEs are simultaneously pursuing external searching for breadth and depth, however, a negative result on innovation outcome followed because of the lack of their internal resources and capacities. Despite these contributions, we have certain limitations that can be regarded as means of future research. Even though breadth and depth are adopted to measure the way of how a firm sources the external knowledge, companies may place the different weight on each source of knowledge. And also, it is difficult to understand how the knowledge gained through external search contributes to a firm's incremental and radical innovation, respectively.

• International Journal of Internet, Broadcasting and Communication
• /
• 제8권2호
• /
• pp.1-22
• /
• 2016

While many organizations believe that cloud computing has the potential to reduce operational cost by abstracting capital assets like data storage center and processing systems into a readily on demand available and affordable operating expenses, still many of these organizations are not aware of the factors determining the performance of cloud computing technology. This paper provides a systematic literature review focusing on the factors determining the performance of cloud computing. In trying to come up with this review, the following sources were searched for relevant articles: ScienceDirect, Scientific.Net, ACMDigital Library, IEEE Xplore, Springer, World Scientific Journal, Wiley Online Library, Academic Search Premier (via EBSCOHost) and EdITLib (Education & Information Technology Digital Library). In first search strategy, approximately 100 keywords related to the research domain like; "Cloud Computing" and "Cloud Services" were used. In second search strategy, 65 keywords more related to the research domain were selected. In the third search strategy, the primary materials were identified and classified according to the paper types (Journal or Conference), year of publication and so on. Based on this study, twenty (20) factors were found that determine the performance of cloud computing. The IT organization needs to consider these twenty (20) factors in order to adopt cloud computing.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
• /
• pp.531-533
• /
• 1997

PI(proportional-integral) controller has been extensively used in the industrial field. But in practicle case, it is difficult to tune PI gains. Evolution Strategy(ES) is used as an effective search algorithm in optimization programs. In this paper we proposed a PI controller for Spot welder system using ES with varying search space. ES with varying search space which depends on fitness values at each generation is used to tune PI control parameters. Simulation results show the proposed algorithm has accurate and robust performance with effective search ability.

• 대한전기학회논문지:전력기술부문A
• /
• 제49권2호
• /
• pp.70-77
• /
• 2000

This paper proposes a method of solving a unit commitment problem using tabu search (TS) which is heuristic algorithm. Ts is a local search method that starts from any initial solution and attempts to determine a better solution using memory structures. In this paper, to reduce the computation time for finding the optimal solution, changing tabu list size as intensification strategy and path relinking method as diversification strategy are proposed. To show the usefulness of the proposed method, we simulated for 10 units system and 110 units system. Numerical results show improvements in the generation costs and the computation time compared with priority list, genetic algorithm(GA), and hybrid GA.

• 한국통신학회논문지
• /
• 제15권4호
• /
• pp.267-277
• /
• 1990

이 논문에서는 인공지능의 기본적인 문제풀이 기법인 상태공간 탐색을 이용하여 한글을 구성하는 기본자소를 분리하여 인식하는 방법을 제안하였다. 자소분리와 인식과정을 보다 밀접하게 결합하기 위하여 문제를 상태공간에 표현하고, 이 공간을 탐색하여 풀이하였다. 그리고 탐색효율을 향상시키기 위하여 한글의 조합규칙에 입각한 구조정보와 매트릭스 평면에서 각 자소가 갖는 위치정보를 이용하였으며, 컴퓨터실험을 통하여 그 유용성을 확인하였다.