• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권9호
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• pp.2098-2117
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• 2012

This paper jointly investigates the bandwidth allocation, transmission strategy and relay positions for two-way transmission aware cellular networks with network coding (NC). Our goal is to minimize the transmission power of mobile terminals (MTs). Consider a cellular system, where multiple MTs exchange information with their common base station, firstly, we propose an efficient bandwidth allocation method and then give a transmission strategy for each MT to determine whether to use relay stations (RSs) for its two-way transmission with the BS or not. To further improve the system performance, the optimal positions of RSs are also jointly discussed. A GA-based algorithm is presented to obtain the optimum positions for RSs. Besides, the impacts of frequency reuse on MT's transmission power and system spectral efficiency (SE) under different number of relays are also discussed in our work. Numerical results show that the proposed NC aware scheme can extend MTs' battery life at least 6% more than traditional method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권11호
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• pp.3751-3774
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• 2014

With the rapid development of wireless communication, the confliction between the scarce frequency resources and the low spectral efficiency caused by the stationary spectrum sharing strategies seriously restricts the evolution of the future mobile communication. For this purpose, cognitive radio (CR) emerges as one of the most promising inventions which can overcome the spectrum shortage. As the key technology and main objective of CR, spectrum sharing can make full use of the limited spectrum, alleviate the scarcity of frequency resources and improve the system utilities, playing thereby an important role in improving the system performance of cognitive radio networks (CRNs). In this survey, the spectrum sharing in CRNs is discussed in terms of the sharing process, mainstream sharing technologies and spectrum sharing models. In particular, comparisons of different spectrum sharing strategies are concluded, as well as that of different spectrum sensing schemes in sharing procedure. Moreover, some application examples of the spectrum sharing in CRNs, such as smart grid, public safety, cellular network and medical body area networks are also introduced. In addition, our previous related works are presented and the open research issues in the field of spectrum sharing are stated as well.

• 한국인터넷방송통신학회논문지
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• 제15권3호
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• pp.91-98
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• 2015

제한된 스펙트럼 자원의 효율적 사용을 위한 하나의 해법으로 GPS 시각 기반의 이동선형주파수변조(SLFM)를 갖는 동일채널 다중국소 레이더 운용을 위한 방법을 제시한다. 제안된 알고리즘은 선택된 SLFM 신호 중에 상호상관 특성으로부터 허용할 수 있는 최소상관 수준을 갖는 SLFM 후보군을 찾는다. 제안 방법의 검증을 위해 단일 톱니 또는 삼각 LFM 신호를 갖는 동일채널에 운용되는 수 개의 레이더에 대해 수치해석을 하였다. 간섭 및 잡음, 알고리즘 한계, 그리고 SLFM 신호의 시각 동기 오류에 대해 탐지 거리 및 거리 윤곽의 계산 결과를 고찰하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권8호
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• pp.2704-2719
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• 2022

Lately, neo-Chinese style furniture has been frequently noticed by product design professionals for the big part it played in promoting traditional Chinese culture. This article is an attempt to use big data semantic analysis method to provide effective design research method for neo-Chinese furniture design. By using big data mining program TEXTOM for big data collection and analysis, the data obtained from typical websites in a set time period will be sorted and analyzed. On the basis of "neo-Chinese furniture" samples, key data will be compared, classification analysis of overall data, and horizontal analysis of typical data will be performed by the methods of word frequency analysis, connection centrality analysis, and TF-IDF analysis. And we tried to summarize according to the related views and theories of the design. The research results show that the results of data analysis are close to the relevant definitions of design. The core high-frequency vocabulary obtained under data analysis, such as popular, furniture, modern, etc., can provide a reasonable and effective focus of attention for the designs. The result obtained through the systematic sorting and summary of the data can be a reliable guidance in the direction of our design. This research attempted to introduce related big data mining semantic analysis methods into the product design industry, to supply scientific and objective data and channels for studies on design, and to provide a case on the practical application of big data analysis in the industry.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권2호
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• pp.618-633
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• 2014

Relay technology is becoming more important for mobile communications and wireless internet of things (IoT) networking because of the extended access network coverage range and reliable quality of service (QoS) it can provide at low power consumption levels. Existing mobile multihop relay (MMR) technology uses fixed-point stationary relay stations (RSs) and a divided time-frame (or frequency-band) to support the relay operation. This approach has limitations when a local fixed-point stationary RS does not exist. In addition, since the time-frame (or frequency-band) channel resources are pre-divided for the relay operation, there is no way to achieve high channel utilization using intelligent opportunistic techniques. In this paper, a different approach is considered, where the use of mobile/IoT devices as RSs is considered. In applications that use mobile/IoT devices as relay systems, due to the very limited battery energy of a mobile/IoT device and unequal channel conditions to and from the RS, both minimum energy consumption and QoS support must be considered simultaneously in the selection and configuration of RSs. Therefore, in this paper, a mobile RS is selected and configured with the objective of minimizing power consumption while satisfying end-to-end data rate and bit error rate (BER) requirements. For the RS, both downlink (DL) to the destination system (DS) (i.e., IoT device or user equipment (UE)) and uplink (UL) to the base station (BS) need to be adaptively configured (using adaptive modulation and power control) to minimize power consumption while satisfying the end-to-end QoS constraints. This paper proposes a minimum transmission power consuming RS selection and configuration (MPRSC) scheme, where the RS uses cognitive radio (CR) sub-channels when communicating with the DS, and therefore the scheme is named MPRSC-CR. The proposed MPRSC-CR scheme is activated when a DS moves out of the BS's QoS supportive coverage range. In this case, data transmissions between the RS and BS use the assigned primary channel that the DS had been using, and data transmissions between the RS and DS use CR sub-channels. The simulation results demonstrate that the proposed MPRSC-CR scheme extends the coverage range of the BS and minimizes the power consumption of the RS through optimal selection and configuration of a RS.

• 한국인터넷방송통신학회논문지
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• 제9권2호
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• pp.59-63
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• 2009

UTP 케이블은 광범위하게 사용되고 있고, 최근에는 UHF 주파수 밴드를 위한 제품도 개발되고 있다. UTP 케이블의 가장 중요한 성능 중 하나는 NEXT 특성이다. NEXT 특성을 만족하는 UTP 케이블을 제조하기 위해서 적당한 피치의 길이를 선택하는 기술을 연구하였다. 전산모사는 선로 사이의 뮤추얼 인덕턴스와 커패시턴스를 포함한 전송선로 모델을 이용하였고, 주파수는 1 MHz에서 600 MHz까지의 데이터로 나타내었다. Cat. 6 케이블 NEXT의 worst margin은 전산모사와 측정 결과가 잘 일치하였다.

• 한국컴퓨터산업학회논문지
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• 제4권12호
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• pp.1083-1092
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• 2003

본 논문에서는 인터넷 상에서 비디오 스트림을 서비스할 때 인기도에 기반으로하는 서비스 지연시간을 최소화하는 방법을 제안하였다. 접근 빈도와 각 서버들의 총 캐슁공간의 상관관계를 고려하여 제안한 알고리즘의 성능을 측정한 결과는 에이전트 캐슁방법보다는 서비스 지연에 대한 캐쉬 활용율이 15%의 향상 그리고 인터벌 캐슁보다는 3배의 정도의 성능 향상을 보여주었다.

• International Journal of Internet, Broadcasting and Communication
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• 제7권2호
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• pp.41-50
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• 2015

As various media have developed in modern society, frequency of use of interactive media has increased which makes interactive function that uses and handles projection mapping and LED screen in set design of broadcasting, concert, play, musical and EDM(Electronic dance music) in real time possible. Development of various media led today's viewers to have higher cultural desire and the need of various interactive performance contents to receive more attention.[1]. This thesis implemented real time VJing that responds to user's motion based on existing H/W by utilizing real time interactive elements.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권7호
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• pp.3356-3374
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• 2018

The healthcare and fitness wearable-device market is considered as the driving force of the entire wearable device market. However, there are concerns with respect to information privacy because wearable devices constantly collect sensitive data such as individuals' health information. Thus, there is a need for a comprehensive understanding from the perspective of information privacy concerns and related behavior. This study investigates factors considered in the privacy calculus of wearable fitness devices, and verifies differences obtained by the privacy calculus process according to the frequency of exercise. The results obtained from a survey of 248 undergraduate students in Korea revealed that service providers should consider users' interests and exercise characteristics in order to mitigate their privacy concerns and encourage continuous use of wearable devices. This study provides useful insights pertaining to users of wearable fitness devices, and targets researchers and practitioners.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권6호
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• pp.1222-1236
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• 2010

In this paper, we propose an improved distributed multi-view video coding method that is robust to illumination changes among different views. The use of view dependency is not effective for multi-view video because each view has different intrinsic and extrinsic camera parameters. In this paper, a modified distributed multi-view coding method is presented that applies illumination compensation when generating side information. The proposed encoder codes DC values of discrete cosine transform (DCT) coefficients separately by entropy coding. The proposed decoder can generate more accurate side information by using the transmitted DC coefficients to compensate for illumination changes. Furthermore, AC coefficients are coded with conventional entropy or channel coders depending on the frequency band. We found that the proposed algorithm is about 0.1~0.5 dB better than conventional algorithms.