• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.7
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• pp.125-131
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• 1989

This paper proposes a new ABTC (Adaptive Block Truncation Coding) algorithm which improves the BTC algorithm for image data compression. A new adaptive block truncation coding which adopts a selective coding scheme depending on the local characteristics of an image has been described. The characteristics of the ABTC algorithm can be summarized as high compression ratio and the algorithm simplicity. Using this algorithm, color images can be coded at a variable bit rate from 1.0 (bit/pel) to 2.56 (bit/pel) and high compression rate (1.3-105 bit/pel) can be achieved without conspicuous image degradation compared with original images.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.294-297
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• 2009

Multi-view video consists of a set of multiple video sequences from multiple viewpoints or view directions in the same scene. It contains extremely a large amount of data and some extra information to be stored or transmitted to the user. This paper presents inter-view correlations among video objects and the background to reduce the prediction complexity while achieving a high coding efficiency in multi-view video coding. Our proposed algorism is based on object-based segmentation scheme that utilizes video object information obtained from the coded base view. This set of data help us to predict disparity vectors and motion vectors in enhancement views by employing object registration, which leads to high compression and low-complexity coding scheme for enhancement views. An experimental results show that the superiority can provide an improvement of PSNR gain 2.5.3 dB compared to the simulcast.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.1
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• pp.1-17
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• 2014

Cooperative spectrum sensing (CSS) is considered as a powerful approach to improve the utilization of scarce radio spectrum resources. However, most of CSS schemes assume all secondary users (SU) are honest, and thus offering opportunities for malicious SUs to launch the spectrum sensing data falsification attack (SSDF attack). To combat such misbehaved behaviors, recent efforts have been made to trust schemes. In this paper, we argue that powering CSS with traditional trust schemes is not enough. The rational SSDF attack is found in this paper. Unlike the simple SSDF attack, rational SSDF attackers send out false sensing data on a small number of interested primary users (PUs) rather than all PUs. In this case, rational SSDF attackers can keep up high trustworthiness, resulting in difficultly detecting malicious SUs in the traditional trust schemes. Meanwhile, a defense scheme using a novel trust approach is proposed to counter rational SSDF attack. Simulation results show that this scheme can successfully reduce the power of rational SSDF, and thus ensure the performance of CSS.

• Journal of Technology Innovation
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• v.13 no.1
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• pp.295-315
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• 2005

The mobile telecommunication service industry plays major role of the realization to the perfect information society in the 21st century and has a great influence in society and culture. The government has enticed the mobile company to keep up to make the mobile service fee low. In this situation, this paper estimates consumer surplus and price elasticity with on-line survey data from the consumer of mobile service. The total estimated consumer surplus of the market is reached to 6.43trillion won. The consumer surplus from SKT is estimated to 4.98trillion won and 1.66trillion won and 0.67trillion won was made by KTF and LGT respectively. The result also shows that consumer surplus is expected to be increased by the increase of the mobile service demand and the sales.

• Proceedings of the Safety Management and Science Conference
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• 2009.04a
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• pp.351-364
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• 2009

As well as the development of the measurement of service quality, various kinds of service measurements are also being developed. Especially the mobile telecommunication service being representative to the mobile telecommunication company would be the mostly developed area. Its development can be understood along with the development of the telecommunication companies as well as cellular companies, not only the service alone. It is a differentiated phenomenon in the current research, such as the organic influence between the service quality and product. Of course there are such products placed on sale and enjoyed the common service, but at present there is another case that the product is on the market exclusively with the mobile company in here. This article is to estimate service efficiency for Mobile Communication and Cellular company. In this paper, We tried to measure the service quality and overall satisfaction by using Data Envelopment Analysis(DEA), degree of combination and top2box which is a little bit different methodology from traditional ones. This paper uses CCR model in DEA to measure service efficiency in the Mobile Communication.

• Journal of Korea Society of Industrial Information Systems
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• v.5 no.4
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• pp.39-46
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• 2000

New products often have in-service reliability problem despite an intensive development program. Therefore reliability data must be collected and analyzed, and improvements designed and implemented. A type of reliability incentive contract which has recently attracted a lot of attention is reliability improvement warranty(RIW). It has been employed by military, airlines, telecommunication systems, and public utilities. An RIW contract requires that the supplies carries out all repairs, modify the equipment to improve its reliability, and provides all spates needed, for a fixed period, for once-off fee. This paper presents the reliability growth analysis and management methods for in-service MC68 microprocessor, which is the main component of the base station controller in PCS(Personal Communication Service) telecommunication system. The methods will provide guidelines to monitor reliability program in planning RIW contract.

• Journal of Information Display
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• v.10 no.4
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• pp.188-194
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• 2009

Conventional stereoscopic (3D) displays using binocular parallax generate unnatural conflicts between convergence and accommodation. These conflicts can affect the observer's ability to fuse binocular images and may cause visual fatigue. In this study, time series changes in visual fatigue and depth sensation when viewing stereoscopic images with changing parallax were examined. In particular, the physiological changes, including the subjective symptoms of visual fatigue, when viewing five parallax conditions, were examined. Then a comparative analysis of the 2D and 3D conditions was performed based on the visual function. To obtain data regarding the visual function, the time series changes in the spontaneous-blinking rate before and during the viewing of 3D images were measured. The time series change results suggest that 2D and 3D images cause significantly different types of visual fatigue over the range of binocular disparity.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.10
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• pp.1751-1768
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• 2011

Falls are one of the most concerned accidents for elderly people and often result in serious physical and psychological consequences. Many researchers have studied fall detection techniques in various domain, however none released to a commercial product satisfying user requirements. We present a systematic modeling and evaluating procedure for best classification performance and then do experiments for comparing the performance of six procedures to get a statistical classifier based wrist-type fall detector to prevent dangerous consequences from falls. Even though the wrist may be the most difficult measurement location on the body to discern a fall event, the proposed feature deduction process and fall classification procedures shows positive results by using data sets of fall and general activity as two classes.

• Journal of Information Management
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• v.29 no.2
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• pp.18-36
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• 1998

This project surveys and analyzes the utilization of domestic database from user's point of view to find out the problems and factors for improvements of that, and makes efficient use of the result of this project as basic data in producing databases. Also it surveys and analyzes information demand for PC telecommunication users and utilization of PC telecommunication, database, and internet to establish directions of the development for the domestic database industry.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.871-874
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• 2002

The information and communications service is recently being broadened, having much faster transmitting speed and multimedia performance. In addition, its introduction to general residential sites and construction of network facilities are being activated. Therefore new setup paradigm is being established other than the environment of plain old telephone service and data communication. In the present paper, the status of international and domestic standardization are reviewed and the operational environment of customer premise telecommunication facilities are investigated and analyzed. In order to enhance customer cabling facilities in Korea. The problems with the operational environment are analyzed, and how to improve customer cabling telecommunication facilities is suggested based on the above.