• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3A
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• pp.238-244
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• 2010

We propose a user selection method in multi-cell multiuser uplink system with the subspace interference alignment to maintain the high sum-rate capacity. The proposed method selects users whose interference to adjacent cells are strong and apply the subspace interference alignment to the users. The proposed method provides that the number of users performing the interference alignment reduces and the high total sum-rate is maintained. Simulation results exhibit the proposed method reduces the number of users who would decompose the channel for the subspace interference alignment by 50% when the required sum-rate is 90% of the maximal achievable sum-rate.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.6
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• pp.60-69
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• 2012

The project on Geonjisan Universal Design Forest Trail in Jeonju City was designed and constructed by an NGO called 'Jeonbuk Forest for Life' which was a winner for the '2008 Open Competition by the 'Committee for Greening Society' established in Korea Land Corporation. The purpose of this study is to evaluate the design satisfaction of UD forest trail. Post Occupancy Evaluation (POE) method was applied to measure the user satisfaction and the total number of users. The main result of the study were as follows: the major users of the Geonjisan UD forest trail were people aged over 60 years old(37%) and the main purpose of trail usage were to 'walk and rest'(51.5%) and to 'exercise and rehabilitation' (40.6%). Furthermore, the overall user rating for the UD forest trail design was "satisfied"(3.91 point in 5-point Likert Scale). The three most influencing factors of the overall user satisfaction were facility management, user conflict, and trail width and slope. About forty-five people were found to be End-user in the UD forest trail while six people were found as End-user in non-UD trails. Most importantly, the number of End-user observed on the UD forest trail was greater than the number found in non-UD forest trail. The result implies that the UD forest trail attracts more End-users and provides opportunity for gathering and interaction with the other users. Moreover, the satisfaction rate for the UD forest trail landscape is found to be high in Likert scale, which we can assume that the well-grown existing trees and topographic features as well as appropriately designed wood-paths influence the high satisfaction rate of the users. The POE of UD forest trail revealed the importance of universal design concept due to its convenient uses of the handicapped, old, weak, pregnant woman or children.

• Journal of the Korean Institute of Landscape Architecture
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• v.18 no.3 s.39
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• pp.155-169
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• 1990

The main purpose of this study is to suggest fundamental materials and a guideline for design through grouping of the users' use route patterns and analyzing determinants to choose those route patterns in urban parks. Study sites were Jungang, Dlseong, and Beomeo park, where located Taegu city-Key results obtained through a series of investigation were as follows : When Users come in and out urban parks, most orientations of their use routes were counterclockwise, and not in such cases, greatly affected by facilities arrangement. There were a large number of users in the main route placed the principal facilities. Users' use route patterns were grouped by their characteristics, which were circulation, semi-circulation, irregular, and piston type. And all the types except piston type can be subdivided into spoon and loope type. Factors analysis to the types produced five meaningful patterns of variables. Five factors were named as dimension of characteristics : Park composition factor, facilities use factor, users' personal factor, park use behavioral factor, routes choice factor.

• Journal of Korea Society of Digital Industry and Information Management
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• v.4 no.1
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• pp.1-8
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• 2008

In the Web 2.0, besides more gaining information on the web, the number of web sites that take advantage of RSS increases explosively. Commonly each users search RSS channels through the web search engine before registering RSS channel's url to the RSS reader. Users judge whether the site is RSS channel or not and register an RSS channel's url through theirs interests. Because accomplished by users themselves, those processes conflict to user's convenience and quick consumption of information. Techniques of current search engines can't provide users with reliable RSS feed information as search results. In this paper, we analysis appropriateness of current search engines' techniques that offer users RSS feed search service and discuss their limitations. Also, we make up RSS feed database through classification of RSS tag being possible to search RSS feed information effectively and apply update rate of each RSS channel's feed to ranking algorithm providing more reliable search results.

• Journal of Information Technology Applications and Management
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• v.20 no.2
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• pp.177-191
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• 2013

Social network has been expected to increase the value of social capital through online user interactions which remove geographical boundary. However, online users in social networks face challenges of assessing whether the anonymous user and his/her providing information are reliable or not because of limited experiences with a small number of users. Therefore. it is vital to provide a successful trust model which builds and maintains a web of trust. This study aims to propose a prediction method for the interpersonal trust which measures the level of trust about information provider in Facebook. To develop the prediction method. we first investigated behavioral research for trust in social science and extracted 5 antecedents of trust : lenience, ability, steadiness, intimacy, and similarity. Then we measured the antecedents from the history of interactive behavior and built prediction models using the two decision trees and a computational model. We also applied the proposed method to predict interpersonal trust between Facebook users and evaluated the prediction accuracy. The predicted trust metric has dynamic feature which can be adjusted over time according to the interaction between two users.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.5 no.1
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• pp.88-93
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• 2005

Web usage mining is a research field for searching potentially useful and valuable information from web log file. Web log file is a simple list of pages that users refer. Therefore, it is not easy to analyze user's current interest field from web log file. This paper presents web usage mining method for finding users' current interest based on fuzzy categories. We consider not only how many times a user visits pages but also when he visits. We describe a user's current interest with a fuzzy interest degree to categories. Based on fuzzy categories and fuzzy interest degrees, we also propose a method to cluster users according to their interests for user modeling. For user clustering, we define a category vector space. Experiments show that our method properly reflects the time factor of users' web visiting as well as the users' visit number.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.15 no.1
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• pp.45-52
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• 2015

Although researchers have proposed various recommendation systems, most recommendation approaches are for single users and there are only a small number of recommendation approaches for groups. However, TV programs or movies are most often viewed by groups rather than by single users. Most recommendation approaches for groups assume that single users' profiles are known and that group profiles consist of the single users' profiles. However, because it is difficult to obtain group profiles, researchers have only used synthetic or limited datasets. In this paper, we report on various group recommendation approaches to a real large-scale dataset in a TV domain, and evaluate the various group recommendation approaches. In addition, we provide some guidelines for group recommendation systems, focusing on home group users in a TV domain.

• Journal of information and communication convergence engineering
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• v.10 no.1
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• pp.53-60
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• 2012

Attribute-based encryption (ABE) is an encryption scheme in which the user is able to decrypt a ciphertext with associated attributes. However, the scheme does not offer the capability of decryption to others when the user is offline. For this reason, the attribute-based proxy re-encryption (ABPRE) scheme was proposed, which combines traditional proxy re-encryption with ABE, so a user is able to empower designated users to decrypt the re-encrypted ciphertext with the associated attributes of designated users. However, previous ABPRE schemes demands a number of pairing operations that imply huge computational overhead. To reduce the number of pairing operations, we reduce the pairing operations with exponent operations. This paper provides a novel approach to an ABPRE scheme with constant pairing operation latency.

• Journal of the Korea Society for Simulation
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• v.11 no.4
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• pp.33-41
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• 2002

One of the key issues in mobile communication system is how to predict the number of calls per each cell. It is an important parameter and usually assumed as random Poisson value. For effective management of cellular network, the average number of calls should be traced and the changes in the numbers need to be promptly detected. In this paper we propose an algorithm detecting the changes in the demands of the users using the technique proposed for point-of-change problem based only on the number of call arrivals. Computer simulation reveals that the proposed method can effectively detect the discord, and the developed model is very accurate as showing mostly less than 1% differences.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4A
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• pp.296-303
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• 2005

In this paper, we evaluate system performance and propose signal separation and detection when a user with one antenna shares the co-channel together with a user with two space-time coded antennas. The proposed technique can identify co-channel users by an interference cancellation method and detect the signals by maximum likelihood method. Simulation results show that the shortcoming of the Minimum Mean-Squared Error technique which can be applied two users with the same number of antenna but can not applied for heterogeneous MIMO users with the different number of antennas. Also, we apply the proposed scheme to OFDM system and evaluate the system performance. By simulations, we identify that the performance of the proposed system is the same as that of the existing single antenna users and improves the performance of the two-antenna MIMO users.