• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 추계학술대회
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• pp.597-598
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• 2011

인지 무선 네트워크에서 제어 및 데이터 정보 전송을 위한 최적의 채널 선택 방법으로 주사용자의 트래픽 정보를 이용하여 유휴 채널 구간을 예측하는 기법을 제안하다. 채널예측을 통해 채널을 선택함으로서 주 사용자에 대한 충돌을 최소화하고 전송효율을 증가시킬 수 있다. 시뮬레이션 결과 제안한 방법이 시스템 수율을 향상시킴과 동시에 주사용자에 대한 간섭 또한 적정한 임계치 이하로 줄이는 것을 확인할 수 있었다.

• 한국컴퓨터정보학회논문지
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• 제21권3호
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• pp.97-104
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• 2016

In this paper, we propose spatial information based simulator for user experience optimization and minimize real space complexity. We focus on developing simulator how to design virtual space model and to implement virtual character using real space data. Especially, we use expanded events-driven inference model for SVM based on machine learning. Our simulator is capable of feature selection by k-fold cross validation method for optimization of data learning. This strategy efficiently throughput of executing inference of user behavior feature by virtual space model. Thus, we aim to develop the user experience optimization system for people to facilitate mapping as the first step toward to daily life data inference. Methodologically, we focus on user behavior and space modeling for implement virtual space.

• 한국IT서비스학회지
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• 제11권4호
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• pp.181-194
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• 2012

The one of the most meaningful change in the recent ubiquitous environment is the omnipresence of public digital display device for providing ubiquitous information. It is the important issue to provide publicity as well as adaptive information to each user in the field of the public digital display device. This research proposes the idea ensuring fast response speed by the selection of user preference function. The preference function is selected by statistics using Zipf distribution in the system comprising mobile device and digital display device based on NFC (Near Field Communication). The idea is proved by CPM-GOMS model and the improvement of user response can be achieved.

• 한국통신학회논문지
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• 제35권4A호
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• pp.332-340
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• 2010

이 논문에서는 중첩 코딩 다중화를 이용하여 다중 사용자 신호를 동시에 전송하는 다중 사용자 다이버시티 스케줄링 방법들을 다룬다. 이 방법들은 다중 사용자 신호들을 동시에 전송함에 따른 제1순위 및 제1 순위 이후 사용자 우선 순위 선정 전략과 사용자 별 전력할당 전략을 결합하는 방식에 따라 다양한 스케줄링 방법들이 가능하도록 한다. 제1 순위 사용자 선정 전략으로는 1) 채널상태 우수 사용자 순서, 2) PFS(proportional fair scheduling) 사용자 순서, 3) 평균 제공 전송률 낮은 사용자 순서를 따르는 3가지 전략들을 고려한다. 제1 순위 이후 사용자순서도 제1 순위 사용자와 동일한 전략을 고려한다. 그러나 다수의 사용자들이 선정되어야 하는 경우, 한번의 PFS 순서를 따르도록 하거나 매 추가 사용자마다 잔여전력과 사용자간 간섭을 고려하여 PFS 기준에 따라 하나의 사용자를 단계적으로 선정하도록 할 수 있다. 전력할당 전략으로는 우선적으로 사용자 별 최대 허용 전송률을 제공하는 전력을 할당하거나 사용자 별 최소 전송률을 제공하는 전력을 할당하고, 잔여전력을 각 사용자에게 재할당하는 두 가지 전략들을 고려한다. 스케줄링 목적으로는 전송률 합 최대화, 형평성 극대화, PFS 방법에 준하는 형평성 유지 및 전송률 합 최대화의 3가지를 고려한다. 또한 각각의 목적을 위하여 max CIR (carrier-to-interference power ratio), max-min fair, PF 스케줄링 방법들([1]과 해당 참고문헌들 참조)을 각각의 목적별 비교 기준으로 정하고, 전송률 합 또는 형평성 측면에서 기준 방법에 준하거나 우수하면서 나머지 척도인 형평성이나 전송률 합이 우수한 방법들을 후보 스케줄링 방법들로 선정한다. 모의실험을 통하여 다양한 스케줄링 방법의 사용자 수에 따른 전송률 합과 JFI(Jain's fairness index)에 따른 형평성을 분석한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권11호
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• pp.4372-4394
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• 2020

The distribution of popular videos incurs a large amount of traffic at the base stations (BS) of networks. Device-to-multi-device (D2MD) communication has emerged an efficient radio access technology for offloading BS traffic in recent years. However, traditional studies have focused on synchronous user requests whereas asynchronous user requests are more common. Hence, offloading BS traffic in case of asynchronous user requests while considering their time-varying characteristics and the quality of experience (QoE) of video request users (VRUs) is a pressing problem. This paper uses social stability (SS) and video loading duration (VLD)-tolerant property to group VRUs and seed users (SUs) to offload BS traffic. We define the average amount of data transmission (AADT) to measure the network's capacity for offloading BS traffic. Based on this, we formulate a time-varying bipartite graph matching optimization problem. We decouple the problem into two subproblems which can be solved separately in terms of time and space. Then, we propose the socially aware D2MD user selection (SA-D2MD-S) algorithm based on finite horizon optimal stopping theory, and propose the SA-D2MD user matching (SA-D2MD-M) algorithm to solve the two subproblems. The results of simulations show that our algorithms outperform prevalent algorithms.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2006년도 춘계학술발표회 논문집
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• pp.211-216
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• 2006

The Constrained Linear Spectral Unmixing(CLSU) is investigated for sub-pixel image processing, Its result is the abundance map which mean fractions of endmember existing in a mixed pixel. Compared to the Linear Spectral Unmixing using least square method, CLSU uses the NNLS (Non-Negative Least Square) algorithm to guarantee that the estimated fractions are constrained. But, CLSU gets Into difficulty in image processing due to select endmember at a user's disposition. In this study, endmember selection optimization method using entropy in the error-image analysis is proposed. In experiments which is used hyperion image, it is shown that our method can select endmember number than CLSU based on unsupervised endemeber selection.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권10호
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• pp.4680-4697
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• 2017

In future, since the user experience plays a more and more important role in the development of today's communication systems, quality of experience (QoE) becomes a widely used metric, which reflects the subjective experience of end users for wireless service. In addition, the energy efficiency is an increasingly important problem with the explosive growth in the amount of wireless terminals and nodes. Hence, a QoE-aware energy efficiency maximization based joint user access selection and power allocation approach is proposed to solve the problem. We transform the joint allocation process to an optimization of energy efficiency by establishing an energy efficiency model, and then the optimization problem is solved by chaotic clone immune algorithm (CCIA). Numerical simulation results indicate that the proposed algorithm can efficiently and reliably improve the QoE and ensure high energy efficiency of networks.

• International Journal of Contents
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• 제5권3호
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• pp.8-13
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• 2009

The recent Web service field emerges as the fastest growing IT paradigm as a result of the increasing interest in SOA (Services-Oriented Architecture) and the expansion of B2B market. With an increasing number of Web service that provide similar features, it becomes more important to provide the most appropriate service for the user's request. A service user in general requires the quality information of Web service when selecting a service among a number of similar Web services. Yet, finding a service through UDDI (Universal Description, Discovery and Integration) does not consider the non-functional aspects of users because it is only based on the functional aspects. That is, the quality, non-functional aspect will be an important factor for the mutual success of the user and provider. Using 3 factors in the Qos factors of the existing studies: the execution cost, reliability, and the quality level, the QoS of Web service is saved and the factors for the QoS are recorded in order to consider non-functional factors when selecting a Web service in this study. The Quality Broker determines the rank and shows the desired result of the service for users. The Quality Broker suggested in this thesis can be used to select a Web Service that considers the user-oriented and non-functional factors.

• International Journal of Advanced Culture Technology
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• 제8권4호
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• pp.212-219
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• 2020

We conducted this study to identify the accommodation applications users' lifestyle types and the composition factors for consumers' accommodation applications selection attributes and to identify the difference in the selection attributes perception of accommodation applications between groups classified by user's lifestyle types. According to the study, 6 factors were derived as the accommodation applications users' lifestyle types and were named social/leisure-oriented type, fashion-seeking type, culture-seeking type, self-examining type, self-centered type, family-oriented type. Also 6 factors were derived as the accommodation applications selection attributes and were named convenience, interactivity, economic efficiency, transaction reliability, product reliability and informativeness. Valid clusters were divided into four groups and were named culture/tourism group, self-examining group, passive and cautious group and Social and practicality-seeking group. Most of the selection attributes perception of accommodation applications between groups had statistically significant differences(p<.05), except for some items of transaction reliability. Based on the results of this study, we should strive to establish effective marketing strategies that reflect differences in the selection attributes perception of the accommodation application between groups classified by users' lifestyle types.

• 한국IT서비스학회지
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• 제12권3호
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• pp.23-37
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• 2013

Social commerce is a subset of e-commerce that involves using social media, and user contributions to assist in the online buying and selling of products and services. Given the rapid growth of social commerce sites such as Groupon, Ticketmonster, and Coupang, it has become critical to understand customer purchasing decision-making processes in the social commerce environment. This study developed a theoretical model to examine the role of social commerce site's stickiness in customers' repurchasing decision processes. This study identifies price attribute, variety of selection, shopping enjoyment, and anger as the key factors of social commerce site's stickiness. Data collected from 164 users who had more purchasing experiences with social commerce for more than 7 months were empirically tested against the research model. The analysis results indicate that social commerce site's stickiness plays an important role in enhancing customer's purchasing behavior. Moreover, price attribute and shopping enjoyment significantly influence social commerce site's stickiness, whereas anger does not significantly affect consumer purchasing decision-making processes. However, contrary to our expectation, variety of selection negatively influences social commerce site's stickiness. The theoretical and practical implications of the findings are described.