• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.151-153
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• 2017

In recommendation system, collaborative filtering is the most important algorithm. Collaborative filtering is a method of making automatic predictions about the interests of a user by collecting preferences or taste information from many users. In this paper five algorithms were used. Metrics such as Recall-Precision, FPR-TPR,RMSE, MSE, MAE were calculated. From the result of the experiment, the user-based collaborative filtering was the best approach to recommend movies to users.

• Journal of the Korea Society of Computer and Information
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• v.23 no.12
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• pp.219-226
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• 2018

Collaborative filtering has been most popular approach to recommend items in online recommender systems. However, collaborative filtering is known to suffer from data sparsity problem. As a simple way to overcome this problem in literature, Jaccard index has been adopted to combine with the existing similarity measures. We analyze performance of such combination in various data environments. We also find optimal weights of factors in the combination using a genetic algorithm to formulate a similarity measure. Furthermore, optimal weights are searched for each user independently, in order to reflect each user's different rating behavior. Performance of the resulting personalized similarity measure is examined using two datasets with different data characteristics. It presents overall superiority to previous measures in terms of recommendation and prediction qualities regardless of the characteristics of the data environment.

• Journal of Korea Multimedia Society
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• v.13 no.10
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• pp.1453-1462
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• 2010

In this paper, a new program recommendation system is proposed to recommend user preferred VOD program in IPTV environment. A proposed system is implemented with collaborative filtering method. For a user profile which describes user program preference, a program preference, sub-genre preference, and US(user similarity) weight of the user neighborhood is averaged and updated every week. In order to evaluate system performance, real 24-weeks cable TV watching data provided by Nilson Research Corp. are modified to fit for IPTV broadcasting environment and the simulation result shows quite comparative quality of recommendation. The experimental results optimum performance when user similarity based weighting, five person per group and five recommendation programs are used.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.11
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• pp.475-482
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• 2013

Several approaches to recommendation systems have been studied. One of the most successful technologies for building personalization and recommendation systems is collaborative filtering, which is a technique that provides a process of filtering customer information based on such information profiles. Collaborative filtering systems, however, have a sparsity if there is not enough data to recommend. In this paper, we suggest a movie recommendation system, based on the weighted personal propensity and the collaborating filtering system, in order to provide a solution to such sparsity. Furthermore, we assess the system's applicability by using the open database MovieLens, and present a weighted personal propensity framework for improvement in the performance of recommender systems. We successfully come up with a movie recommendation system through the optimal personalization factors.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2007.05a
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• pp.179-188
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• 2007

디지털 기기 가 보편 화 되 면서 많 은 디지털 컨텐츠가 생성되고 있다. 또한, 인터넷 서비스의 발전으로 이들 컨텐츠를 과거에 비해 손쉽게 웹 상에 개제할 수 있게 되 었다. 따라서, 많은 컨텐츠를 추 천해 주기 위해 추천 시스템에 관한 연구가 활발히 진행되고 있다. 이들 컨텐츠가 기존의 텍스트 기반에서 사진이나 동영상, 사운드 등 컴퓨터가 자동으로 내용을 파악하기 힘든 컨텐츠로 변화하면서, 내용의 파악이 필요 없 는 협력적 여 과(Collaborative Filtering)가 추천 시스템에서 유 용하게 이 용될 수 있다. 또한 web 2.0의 영향으로 컨텐츠를 분류하고 재검색을 용이하게 하기 위해 태깅(tagging)을 제공하는 서비스가 많아지고 있다. 본 논문에서는 내용 파 악이 힘든 컨텐츠의 효과적인 추천을 위해 협력적 여과(Collaborative Filtering)와 협력적 태깅(Collaborative Tagging)을 접목시킨 방법을 제안하고, 전통적인 협력적 여과 방법과 제안한 방법의 비교 실험을 통하여 협력적 여과 방법에서의 태 깅의 효과에 대 해 논한다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11S
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• pp.3420-3433
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• 1999

Since most of CSCW(Computer-Supported Cooperative Work) systems have been developed for particular computing platforms, they are usable only within the specific organizations supporting those particular platforms. Recently, according to the rapid growth and continuing success of the World-Wide Web(WWW or Web) which offers a globally accessible platform-independent infrastructure, many CSCW systems has been constructed and is being developed on the basis of the Web. As one of such CSCW systems, in this paper, we describe the design and implementation of the CoSpace system. The CoSpace system provides shared workspaces, which enable members of a work group easily share information for collaborative work through their Web Browsers. The shared workspaces support information sharing and management between users, and also support event monitoring and synchronization between collaborative works.

• Journal of Astronomy and Space Sciences
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• v.19 no.2
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• pp.107-122
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• 2002

Multi-body spacecraft attitude and configuration control formulations based on the use of collaborative control theory are considered. The control formulations are based on two-player, nonzero-sum, differential game theory applied using a Nash strategy. It is desired that the control laws allow different components of the multi-body system to perform different tasks. For example, it may be desired that one body points toward a fixed star while another body in the system slews to track another satellite. Although similar to the linear quadratic regulator formulation, the collaborative control formulation contains a number of additional design parameters because the problem is formulated as two control problems coupled together. The use of the freedom of the partitioning of the total problem into two coupled control problems and the selection of the elements of the cross-coupling matrices are specific problems ad-dressed in this paper. Examples are used to show that significant improvement in performance, as measured by realistic criteria, of collaborative control over conventional linear quadratic regulator control can be achieved by using proposed design guidelines.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.619-620
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• 2006

In this paper, the CAE Service System for Collaborative Engineering Environment with web services and Multi-frontal Method has been investigated and developed. The enabling technologies such as SOAP and .NET Framework play great roles in the development of integrated distributed application software. In addition to the distribution of analysis modules, numerical solution process itself is again divided into parallel processes using Multi-frontal Method for computational efficiency. We believe that the proposed approach for the analysis can be extended to the entire product development process for sharing and utilizing common product data in the distributed engineering environment.

• Proceedings of the Safety Management and Science Conference
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• 2005.05a
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• pp.81-89
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• 2005

The purpose of this study is to develop S/W of the web-based collaborative warehouse management system using RFID(Radio Frequency Identification). This S/W System supports the realtime inventory management and collaborative operations of relational companies in SCM. We look for benefits-reduce inventory levels, maxmize use of warehouse space, decrease the logistic cost, and increase competitive power of company, using this S/W

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2003.05a
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• pp.416-425
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• 2003

Recommender systems are a personalized information filtering technology to help customers find the products they would like to purchase. Collaborative filtering (CF) has been known to be the most successful recommendation technology. However its widespread use in e-commerce has exposed two research issues, sparsity and scalability. In this paper, we propose several hybrid recommender procedures based on web usage mining, clustering techniques and collaborative filtering to address these issues. Experimental evaluation of suggested procedures on real e-commerce data shows interesting relation between characteristics of procedures and diverse situations.