• Journal of Intelligence and Information Systems
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• v.22 no.3
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• pp.113-127
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• 2016

Among the techniques for recommendation, collaborative filtering (CF) is commonly recognized to be the most effective for implementing recommender systems. Until now, CF has been popularly studied and adopted in both academic and real-world applications. The basic idea of CF is to create recommendation results by finding correlations between users of a recommendation system. CF system compares users based on how similar they are, and recommend products to users by using other like-minded people's results of evaluation for each product. Thus, it is very important to compute evaluation similarities among users in CF because the recommendation quality depends on it. Typical CF uses user's explicit numeric ratings of items (i.e. quantitative information) when computing the similarities among users in CF. In other words, user's numeric ratings have been a sole source of user preference information in traditional CF. However, user ratings are unable to fully reflect user's actual preferences from time to time. According to several studies, users may more actively accommodate recommendation of reliable others when purchasing goods. Thus, trust relationship can be regarded as the informative source for identifying user's preference with accuracy. Under this background, we propose a new hybrid recommender system that fuses CF and social network analysis (SNA). The proposed system adopts the recommendation algorithm that additionally reflect the result analyzed by SNA. In detail, our proposed system is based on conventional memory-based CF, but it is designed to use both user's numeric ratings and trust relationship information between users when calculating user similarities. For this, our system creates and uses not only user-item rating matrix, but also user-to-user trust network. As the methods for calculating user similarity between users, we proposed two alternatives - one is algorithm calculating the degree of similarity between users by utilizing in-degree and out-degree centrality, which are the indices representing the central location in the social network. We named these approaches as 'Trust CF - All' and 'Trust CF - Conditional'. The other alternative is the algorithm reflecting a neighbor's score higher when a target user trusts the neighbor directly or indirectly. The direct or indirect trust relationship can be identified by searching trust network of users. In this study, we call this approach 'Trust CF - Search'. To validate the applicability of the proposed system, we used experimental data provided by LibRec that crawled from the entire FilmTrust website. It consists of ratings of movies and trust relationship network indicating who to trust between users. The experimental system was implemented using Microsoft Visual Basic for Applications (VBA) and UCINET 6. To examine the effectiveness of the proposed system, we compared the performance of our proposed method with one of conventional CF system. The performances of recommender system were evaluated by using average MAE (mean absolute error). The analysis results confirmed that in case of applying without conditions the in-degree centrality index of trusted network of users(i.e. Trust CF - All), the accuracy (MAE = 0.565134) was lower than conventional CF (MAE = 0.564966). And, in case of applying the in-degree centrality index only to the users with the out-degree centrality above a certain threshold value(i.e. Trust CF - Conditional), the proposed system improved the accuracy a little (MAE = 0.564909) compared to traditional CF. However, the algorithm searching based on the trusted network of users (i.e. Trust CF - Search) was found to show the best performance (MAE = 0.564846). And the result from paired samples t-test presented that Trust CF - Search outperformed conventional CF with 10% statistical significance level. Our study sheds a light on the application of user's trust relationship network information for facilitating electronic commerce by recommending proper items to users.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11
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• pp.3020-3033
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• 1999

Role-Based Access Control(RBAC) security policy is being widely accepted not only as an access control policy for information security but as both a natural modeling tool for management structure of organizations and flexible permission management framework in various commercial environments. Important functions provided by the current RBAC model are to administrate the information on the components of RBAC model and determine whether user's access request to information is granted or not, and most researches on RBAC are for defining the model itself, describing it in formal method and other important properties such as separation of duty. As the current RBAC model which does not define the definition, design and operation for applications is not suitable for automated information systems that consist of various applications, it is needed that how applications should be designed and then executed based on RBAC security model. In this paper, we describe dynamic properties of session which is taken for a passive entity only activated by users, as a vehicle for building and executing applications in an automated information systems. And, a framework for session-oriented separation of duty property, application design and operation is also presented.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.11-15
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• 2003

Amount of biological data information has been increasing exponentially. In order to cope with this bio-information explosion, it is necessary to construct a biological data information integration system. The integration system could provide useful services for bio-application developers by answering general complex queries that require accessing information from heterogeneous bio data sources, and easily accommodate a new database into the integrated systems. In this paper, we analyze architectures and mechanisms of existing integration systems with their advantages and disadvantages. Based on this analysis and user requirement studies, we propose an integration system framework that embraces advantages of the existing systems. More specifically, we propose an integration system architecture composed of a mediator and wrappers, which can offer a service interface layer for various other applications as well as independent biologists, thus playing the role of database management system for biology applications. In other words, the system can help abstract the heterogeneous information structures and formats from the application layer. In the system, the wrappers send database-specific queries and report the result to the mediator using XML. The proposed system could facilitate in silico knowledge discovery by allowing combination of numerous discrete biological information databases.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.1
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• pp.34-42
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• 2012

Life and Property damage has increased during traffic congestion and isolation because natural disasters such as flood and landslide have occurred every year. When disaster occurs, if there is insufficient information in advance when entering the flooding areas which subsequently cause confusion. In this paper, we developed the system that could provide display of detour route using disaster information and evacuation route in disaster areas. User will receive result of analysis using smart phone application to prevent additional damages when disaster areas were entered by manager.

• Journal of Information Management
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• v.40 no.1
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• pp.1-27
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• 2009

The study investigated the indicators for information service system performance measurement through the review on the related literatures, and developed 16 indicators for the performance measurement in 4 areas of library visit, lending, reference service and user instruction, and electronic service. And then with the indicators, the study surveyed 6 academic libraries including each 2 of large, middle, and small sized academic libraries. Based on the survey results, the study made a proposal for the application of performance indicator and the improvement of information service system performance.

• Spatial Information Research
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• v.23 no.6
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• pp.89-98
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• 2015

In this study, The criteria for assessing the security-related functions and services using spatial information is deduced, and orders of priority a priority for the applicable alternatives of functions/services of intelligent security service application based on spatial information are suggested by calculating relative importance. Also this study suggested connection plan about service implementation of national security services by government ministry & local government. And, the intelligent security app service model which has possible substantiation and commercialization is proposed. This study performed the AHP as the final assessment criterions by 3 item in 1st class and 12 item in 2nd class. And, tried to implementation methods of the intelligent security service application(ex. control of emergency and the crime opportunity, real-time location tracking of protector, the device for missing child & dementia patient, user participation & provision of information).

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.10a
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• pp.106-112
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• 2008

Personalization is user oriented dynamic method based on user preferences for easy access to what users want to view or get. It has become more important in mobile domain with rapid growth of wireless Internet and mobile phone market after success of web based market and therefore, it can be applied to service of spatial analysis result. In this paper, spatial analysis using user profile and notification service methods are proposed as one of personalized spatial data service methods for mobile users. A service system for spatial analysis with user profile is designed to prove possibility of spatial analysis based on user preferences and notification service is also designedto show generated output can be sent to user's mobile devices efficiently to make users informed of preferred information. Prototype system is implemented and it is applied to real estate data that has many selectable conditions by users. Information service based on user preferences can be applied to spatial data by using proposed system and it is efficient when cache module is used to shorten response time. Various user models for application domains and performance evaluation methods need to be developed in the future.

• Journal of the Korea Society of Computer and Information
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• v.9 no.3
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• pp.63-69
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• 2004

The purpose of this paper is to design a system model which is needed for integrating the secure role-based access control model into web-based application systems. For this purpose, firstly, the specific system architecture model using a user-pull method is presented. This model can be used as a design paradigm. Secondly, the practical system working model is proposed. which specifies the mechanism that performs role-based access control in the environment of web-based application systems. Finally, the comparison and analysis is shown in which the merits with the proposed system model is presented.

• Journal of Korean Institute of Industrial Engineers
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• v.33 no.4
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• pp.402-409
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• 2007

Markov Chains has proven to be effective in predicting human behaviors in the areas of web site assess, multimedia educational system, and driving environment. In order to extend an application area of predicting human behaviors using Markov Chains, this study was conducted to investigate whether Markov Chains could be used to predict human behavior in selecting mobile phone menu item. Compared to the aforementioned application areas, this study has different aspects in using Markov Chains : m-order 1-step Markov Model and the concept of Power Law of Learning. The results showed that human behaviors in predicting mobile phone menu selection were well fitted into with m-order 1-step Markov Model and Power Law of Learning in allocating history path vector weights. In other words, prediction of mobile phone menu selection with Markov Chains was capable of user's actual menu selection.

• Journal of the Korea Society of Computer and Information
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• v.22 no.8
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• pp.9-14
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• 2017

In this paper, we propose the smart belt system for preventing loss of items using Beacon. The proposed system monitors the distances of the registered items via the belt that is always worn. The belt determines the loss of the items by measuring the relative distance via RSSI (Received Signal Strength Indicator) value of the signals received from the BLE (Bluetoothl Low Energy) sensor, which is attached on the items such as bags and wallets. If the registered item is determined to be lost, the belt rings to remind the user of the loss. The missing status could be known to users through the smartphone application connected to the belt. The smartphone application communicates with the belt using Beacon, and provides users with a quick and easy way to check the status of their items.