• International Journal of Naval Architecture and Ocean Engineering
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• 제9권3호
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• pp.256-265
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• 2017

In this paper, an ascheme is proposed for multiuser underwater acoustic communication by using the multi-chirp rate signals. It differs from the well known TDMA (Time Division Multiple Access), FDMA (Frequency Division Multiple Access) or CDMA (Code Division Multiple Access), by assigning each users with different chirp-rate carriers instead of the time, frequency or PN code. Multi-chirp rate signals can be separated from each other by FrFT (Fractional Fourier Transform), which can be regarded as the chirp-based decomposing, and superior to the match filter in the underwater acoustic channel. VTRM (Virtual Time Reverse Mirror) is applied into the system to alleviate the ISI caused by the multipatch and make the equalization more simple. Results of computer simulations and pool experiments prove that the proposed multiuser underwater acoustic communication based on the multi-chirp rate exhibit well performance. Outfield experments carrie out in Xiamen Port show that using about 10 kHz bandwidth, four users could communicate at the same time with 425 bps with low BER and can match the UAC application.

• Journal of Information Technology Applications and Management
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• 제16권4호
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• pp.93-107
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• 2009

This study investigated consumer preferences for Internet medical information service in China using the multi-attribute utility theory. The multi-attribute utility theory is a compositional approach for modeling consumer preferences wherein researchers calculate the overall service utility by summing up the evaluation results for each attribute. We found that Chinese Internet medical information users consider the availability of information and quick response to be the most important attributes. Further, they think that the comment feature is less important as compared to other attributes such as costs and updates. In addition, we found that the Internet users having more Internet experience consider these attributes to be more important as compared to the people who are just beginning to surf the Internet. For any successful Internet business, Internet marketers should assess individual-level preference and accordingly organize a fresh campaign. As of now, Internet marketers need estimation methods to predict the market performance of new services in many different business environments. We believe that the multi-attribute utility theory is a useful approach in this regard.

• 교육녹색환경연구
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• 제2권1호
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• pp.49-67
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• 2002

The purpose of this study is to be able to accept various educational processes with a few classrooms by multi-purpose uses special classrooms and supporting facilities of medium and small sized elementary school. For this purpose, I had divided into three parts by analyzing correlation of each classrooms according to the types of lessons, necessary equipment, building equipment environment, the need of users. The types of lessons and necessary facilities make the scope of each classrooms throughout Correspondence Analysis, and the need of users that is the recognized similarity between each rooms by teachers, make the scope by using Multi-Dimensional Scaling(MDS). Establish the final scope by combining and analyzing the already classified rooms by each factor. Lastly, calculate the numbers of rooms by applying the usage rate of each classified classroom and examine the standard of planning and the example of composition for the multi-purpose uses of combined room.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권9호
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• pp.3293-3311
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• 2015

Cloud services are required to be composed as a single service to fulfill the workflow applications. Service composition in Cloud raises new challenges caused by the diversity of users with different QoS requirements and vague preferences, as well as the development of cloud computing having geographically distributed characteristics. So the selection of the best service composition is a complex problem and it faces trade-off among various QoS criteria. In this paper, we propose a Cloud service composition approach based on evolutionary algorithms, i.e., NSGA-II and MOPSO. We utilize the combination of multi-objective evolutionary approaches and Decision-Making method (AHP) to solve Cloud service composition optimization problem. The weights generated from AHP are applied to the Crowding Distance calculations of the above two evolutionary algorithms. Our algorithm beats single-objective algorithms on the optimization ability. And compared with general multi-objective algorithms, it is able to precisely capture the users' preferences. The results of the simulation also show that our approach can achieve a better scalability.

• 한국통신학회논문지
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• 제25권12A호
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• pp.1828-1835
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• 2000

In this paper, we analyzed the other-cell interference characteristics for various non-uniform traffic distributions and their effects on the capacity of multi-cell CDMA system. We consider three different traffic distributions, i.e., linear, exponential and Gaussian traffic distribution with distribution parameters. Changing the distribution parameter, we can obtain the center-focused distributions or uniform distributions for each model. From the results of other-cell interference calculation we can see that the other-cell interference decreases, as the user concentrates on the base station. Also using frequency reuse efficiency indicating the capacity reduction of a multi-cell system when compared to a single cell system, we evaluate the effect of traffic distribution on the reverse link CDMA capacity. For linear case, the capacity of multi-cell system is reduced to 0.637∼0.867 times that of single cell system. On the other hand, for both exponential and Gaussian cases, the capacity under a multi-cell environment is equal to 70∼100% of that under a single cell. Therefore, we conclude that the average capacity of multi-cell CDMA system are increased when users are likely to be at near the cell base station due to reduced total other-cell interference and decreased when users exist at near the cell edge regardless of traffic distribution models.

• 복식문화연구
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• 제20권1호
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• pp.121-127
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• 2012

When people are asked to described certain textiles, they frequently refer to the expressions of its properties such as attractiveness, uniqueness, shininess, robustness, comfortability, and so on. It shows how senses play important role in it. Human employs their senses when interacting with textiles, most notably visual and tactile/ haptic to absorb its expressive properties. Yet, our sensorial experiences may amplify when interacting with those of traditional textiles, such as batik, as we can entice sensations when seeing its motifs and patterns, smelling its materials, and touching its surfaces. The multi-sensorial importance of seeing, smelling, and touching in the interaction with and experience of textiles suggests that one should address senses in a systematic way when evaluating users' perception on traditional textiles. To address this issue, the paper proposes the incorporation of Kansei Engineering (KE) approach for identifying multi-sensorial experiences on the expressive properties of traditional textiles, using batik as a case of study. KE approach address person's psychological understanding when observing things in order to analyze and study the inherent relationship between person's perceptual knowledge and objects evaluated. This paper outlines the use of KE approach in correlating sensorial perceptions when experience with traditional textiles and ultimately expose users' preferences toward them. Background of KE approach on textiles will be explored and its application for the multi-sensorial investigation of traditional textiles will be discussed.

• Journal of Communications and Networks
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• 제18권1호
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• pp.112-122
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• 2016

Cognitive radio (CR) is considered an attractive technology to deal with the spectrum scarcity problem. Multi-radio access technology (multi-RAT) can improve network capacity because data are transmitted by multiple RANs (radio access networks) concurrently. Thus, multi-RAT embedded in a cognitive radio network (CRN) is a promising paradigm for developing spectrum efficiency and network capacity in future wireless networks. In this study, we consider a new CRN model in which the primary user networks consist of heterogeneous primary users (PUs). Specifically, we focus on the energy-efficient resource allocation (EERA) problem for CR users with a special location coverage overlapping region in which heterogeneous PUs operate simultaneously via multi-RAT. We propose a two-tier crossover genetic algorithm-based search scheme to obtain an optimal solution in terms of the power and bandwidth. In addition, we introduce a radio environment map to manage the resource allocation and network synchronization. The simulation results show the proposed algorithm is stable and has faster convergence. Our proposal can significantly increase the energy efficiency.

• 한국컴퓨터정보학회논문지
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• 제20권1호
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• pp.143-151
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• 2015

바이오인식 기술은 기존의 PIN이나 패스워드와 달리 분실하거나 도용될 가능성이 적기 때문에 새로운 인증 수단으로 대체되고 있다. 그러나 바이오인식 정보는 PIN이나 패스워드 혹은 개인정보와 달리 노출되어 도용이 된다면 수정할 방법이 없다. 따라서, 기존의 단일 모달리티에 단일 바이오인식 정보처럼 노출이 되면 치명적인 방법이 아닌 다중 모달리티와 다중 바이오인식 정보를 사용하여 사용자와 TTP 혹은 금융기관 간 인증하도록 함으로써 본 논문은 보다 신뢰성있는 방법을 제안하고 기존의 방법과 보안 및 성능을 비교한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권9호
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• pp.4329-4348
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• 2019

Mobile cloud computing (MCC) can offload heavy computation from mobile devices onto nearby cloudlets or remote cloud to improve the performance as well as to save energy for these devices. Therefore, it is essential to consider how to achieve efficient computation offloading with constraints for multiple users. However, there are few works that aim at multi-objective problem for multiple users. Most existing works concentrate on only single objective optimization or aim to obtain a tradeoff solution for multiple objectives by simply setting weight values. In this paper, a multi-objective optimization model is built to minimize the average energy consumption, time and cost while satisfying the constraint of bandwidth. Furthermore, an improved multi-objective optimization algorithm called D-NSGA-II-ELS is presented to get Pareto solutions with better convergence and diversity. Compared to other existing works, the simulation results show that the proposed algorithm can achieve better performance in terms of energy consumption, time and cost while satisfying the constraint of the bandwidth.

• 인터넷정보학회논문지
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• 제12권2호
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• pp.113-122
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• 2011

최근, 온라인상에서 사용자간 관계형성 및 커뮤니케이션을 지원하는 Social Network Service(SNS)들이 주목을 받고 있다. SNS에서 형성되는 사용자 정보와 그들의 활동에 대한 정보는 사용자에 대한 특징적인 정보로서 추천과 같은 외부서비스에서 재사용될 수 있는 유용한 정보로 여겨진다. 기존의 사용자 기본 프로파일 정보를 통한 분석이나, 친밀도 및 유사도를 도출하기 위한 단편적인 분석 방법은 가공된 정보의 활용에 있어 한계점을 지닌다. 본 논문에서는 사용자의 SNS활동들로 부터 사용자간 상호영향을 도출하고 다차원 상호관계(Multi-dimension interaction)를 표현 할 수 있는 통합 된 프로파일 모델을 정의하고 이를 도출하기 위한 시스템을 제안한다. 제안된 시스템은 대표적인 SNS인 트위터(Twitter.com)부터 사용자 정보를 수집하여 정보의 재가공을 수행한다. 본 논문의 실험에서는 가공된 정보를 통해 얻을 수 있는, 기존 방식에서는 드러나지 않던 사용자간의 새로운 관계들에 대해 설명한다. 가공된 정보는 특정 사용자의 통합 프로파일로서 컨텐츠 아이템 추천과 같은 외부서비스에서 활용가능 할 것으로 기대된다.