• Journal of the Korean Society for Library and Information Science
• /
• v.34 no.2
• /
• pp.117-133
• /
• 2000

This study evaluated two Korean search engines, Korean AltaVista and Naver, using user-based measures by Su(1998). Measures are based on four evaluation criteria: efficiency, precision, validity of the links, user satisfaction. For this study, users conducted searches on two engines with their own search queries and performed relevance judgement. Study results indicate that efficiency, validity of the links, and user' s satisfaction ratios of system features are significantly different between two search engines, although there is no significant difference of precision. This study can be used as a framework for usercentered evaluation and utilized to enhance Korean search engines.

• Journal of Distribution Science
• /
• v.4 no.1
• /
• pp.103-120
• /
• 2006

This study is composed of analyses about whether intensifying the attribute level of alternatives presented to consumers makes the effect of intensifying attributes and there is any significant difference among effects of the intensified attributes. For this, the most favorite alternative is extracted from each group of computers and jeans through conjoint analysis, which is used as a standard alternative during the process of experimentation. In conclusion, this research suggests that in terms of business, by intensifying the latter attribute of products rather than the early attribute, an enterprise acquire distinct and competitive superiority over similar competing products (esp. functional products), and theoretically, by expanding and analyzing decision models it can predict consumers' behaviors more correctly.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2009.05a
• /
• pp.1898-1902
• /
• 2009

영상 분석에서는 적절한 탐색 범위를 결정하는 것이 측정의 정확도에 큰 영향을 미친다. 탐색 범위는 흐름장의 상태에 따라 달라진다. 탐색 범위를 작게 잡을 경우 분석 시간이 절약되고 정확도를 높일 수 있으나, 지나치게 작게 되는 경우는 오히려 유속 분포 추정에 큰 오류를 범할 가능성이 있다. 반면에 탐색 범위를 크게 잡을 경우에는 유속 분포 추정에 큰 오류를 범할 가능성은 줄어들지만, 분석 시간이 길게 되며 전반적인 정확도는 낮아지게 된다. 따라서, 적절한 탐색 범위의 설정은 영상 분석의 정확도 향상에서 큰 관건이 된다. 실험실 수로의 경우 유속 분포에 대해 사전에 알고 있는 경우가 많으며, 유속이나 수위가 크게 변하지 않으므로, 적절한 탐색 범위의 선정이 어렵지 않다. 그러나, 현장 적용을 위한 고정식 표면영상유속계의 경우, 수위와 유량이 급변하고 또한 수위에 따른 유속 분포의 변화가 매우 심하므로 적절한 탐색 범위의 선정이 용이하지 않다. 본 연구에서는 고정된 탐색 범위를 설정하여 일차적으로 유속 분포를 추정하고, 여기서 얻은 유속 분포에 기반하여 탐색 영역을 보다 정밀하게 설정하고 재탐색을 하는 방법을 적용하였다. 이러한 유속 분포에 기반한 탐색 영역의 설정을 통하여 유속 분포 추정의 정확성을 크게 향상시킬 수 있다. 괴산댐 하류에 위치한 수전교에서 2008년 7월 $23{\sim}24$일 동안의 영상 자료를 이용한 추정 결과, 추정 유량의 오차를 절반 정도 줄여서 측정의 정확도를 향상시킬 수 있었다.

• Journal of the Korea Society of Computer and Information
• /
• v.11 no.1 s.39
• /
• pp.129-138
• /
• 2006

Various techniques have been applied to solve the maximal covering problem. Tabu search is also one of them. But, existing researches were lacking of the synthetic analysis and the effort for performance improvement about neighborhood search techniques such as hill-climbing search and simulated annealing including tabu search. In this paper, I introduce the way to improve performance of neighborhood search techniques through various experiments and analyses. Basically, all neighborhood search algorithms use the k-exchange neighborhood generation method. And I analyzed how the performance of each algorithm changes according to various parameter settings. Experimental results have shown that simple hill-climbing search and simulated annealing can produce better results than any other techniques. And I confirmed that simple hill-climbing search can produce similar results as simulated annealing unlike general case.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
• /
• 2006.05a
• /
• pp.37-42
• /
• 2006

GIS분야에 대한 다양한 연구가 진행됨에 따라 그 활용에 대한 관심도 확대되고 있다. Open GIS Consortium에서는 GML(Geography Markup Language)을 개발하여 이를 GIS 응용분야에 활용하고자 하는 연구가 활발히 진행되고 있다. GML데이터에서 의미 있는 정보를 추출하기 위해서는 데이터 마이닝 기법 활용이 필수적이다 최근에 데이터마이닝 기법 중 연관규칙을 이용한 탐색 방법이 제안되었다. 그러나 이 방법은 전체 데이터를 대상으로 의미 있는 정보를 탐색 하므로, 데이터 내에 포함되어 있는 부분 속성인 지리 공간적 연관성을 탐색하는데 한계를 가지고 있다. 따라서 녈 연구에서는 GML데이터에서 부분적 속성을 고려한 지역적 연관규칙 탐색 기법을 제안한다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2000.04b
• /
• pp.307-309
• /
• 2000

진화 알고리즘은 현재까지 다양한 최적화 문제들에 사용되어 왔고, 또한 이러한 최적화 문제들은 효율적으로 해결하기 위하여 많은 진화 알고리즘이 개발되어 왔다. 그러나 이러한 진화 알고리즘들의 공통적인 문제점은 탐색공간의 확대에 대하여 전반적으로 탐색시간이 오래 걸린다는 것이다. 실제로 최적화 해야 할 변수의 증가에 따라 탐색 차원이 증가하므로 탐색 시간도 기하급수적으로 늘어난다. 따라서 최근의 진화 알고리즘에 대한 연구는 탐색공간의 축소나, 진화 속도의 향상에 초점이 맞추어져 있었고, 이러한 경향에 따라 많은 연구성과가 있었다. Potter와 Dejong의 협력 공진화와, Weicker의 적응적 공진화가 바로 그것이다. 그러나 이 방법들도 최적화 해야 할 변수들이 서로 강한 의존성을 가지고 있는 경우나, 대부분의 변수가 서로 의존성을 가지고 있는 경우에는 그다지 좋은 결과를 보이지 못하는 문제점을 가지고 있다. 본 논문에서는 이러한 연구들을 기반으로 하여 각 방법의 단점들을 보완함으로써 효율을 향상시킨 새로운 진화 알고리즘을 제안한다.

• Journal of the Korean Society for information Management
• /
• v.21 no.3
• /
• pp.203-225
• /
• 2004

This study is to investigate the characteristics of the Invisible Web and many search services designed to serve as gateways to the Invisible Web and to evaluate searching the Invisible Web in the Services. The four services for searching the Invisible Web were selected to search the Invisible Web with 11 queries, that are Google as portals, ProFusion and Search.com as Invisible Web meta search engines, and IncyWincy as Invisible Web search engines. It was found that the effectiveness of Google's Invisible Web searching was better compared with the three Invisible Web search tools but the difference between the four systems was not significant((${\alpha}$=.055) The Invisible Web meta searching was better than the Web meta searching in the three search tools at the statistically significant level. The effectiveness measurement based on the ranks and relevance degree(quality) of relevant documents retrieved seemed appropriate to the ranked search results.

• Journal of the Korean Society for Library and Information Science
• /
• v.31 no.3
• /
• pp.209-237
• /
• 1997

The main purpose of this study is to find the difference of information searching behaviours consist of information pursuit cognition and searching character by time pressure of researchers. The majar findings and result by time pressure of researchers are summarized as follows : In terms of information retrieval systems, according to the time pressure, there is a significant difference in recall, precision and diversity. In terms of main used material, there is a significant difference in a book, a research report, and a Journal. In terms of resource types, there is a significant difference in both record and human resource. Also, in terms of searching behaviours, there is a difference to spend time for information collection and information searching strategy, and to decide information searching method and degree of searching.

• Journal of the Korea Society of Computer and Information
• /
• v.17 no.6
• /
• pp.13-27
• /
• 2012

Integer programming-based local search(IPbLS) is a kind of local search based on simple hill-climbing search and adopts integer programming for neighbor generation unlike general local search. According to an existing research [1], IPbLS is known as an effective method for the multidimensional knapsack problem(MKP) which has received wide attention in operations research and artificial intelligence area. However, the existing research has a shortcoming that it verified the superiority of IPbLS targeting only largest-scale problems among MKP test problems in the OR-Library. In this paper, I verify the superiority of IPbLS more objectively by applying it to other problems. In addition, unlike the existing IPbLS that combines simple hill-climbing search and integer programming, I propose methods combining other local search algorithms like hill-climbing search, tabu search, simulated annealing with integer programming. Through the experimental results, I confirmed that IPbLS shows comparable or better performance than the best known heuristic search also for mid or small-scale MKP test problems.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.9 no.1
• /
• pp.1-13
• /
• 2014

This study examines the relationship between firms' external search strategy and their innovation performance. In addition to revisiting the relationship between open search strategy and product innovation, we further extend the impact of use of external knowledge sources to process and organizational innovation. Using the 2010 Korean Innovation Survey (KIS) of manufacturing firms, we report that on average, venture firms search more widely (external search breadth) and deeply (external search depth) across a variety of external search channels than non-venture firms. We then further explore the impact of venture and non-venture firms' use of external search strategies on innovation performance. We find that both searching widely and deeply increase the likelihood of non-venture firm's successes in product, process and organizational innovation. Similar results can be found for the venture firm's success in organizational innovation. However, only searching deeply increases the likelihood of venture firms' success in product and process innovation.