• Journal of Broadcast Engineering
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• v.24 no.2
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• pp.251-263
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• 2019

Recently the huge demand for Internet media streaming has dramatically increased the cost of the CDN (Content Delivery Network) and the need for a means to reduce it is increasing day by day. In this situation, a P2P-assisted DASH technology has recently emerged, which uses P2P (Peer-to-Peer) communications based on WebRTC (Web Real-Time Communication) standards to reduce the CDN cost. This paper proposes an algorithm that can significantly improve CDN cost savings in this technology by selecting peers based on the transport history. Also we implemented this algorithm in an experimental system and, after setting experimental conditions that emulate the actual mobile network environment, we measured the performance of the experimental system. As a result, we demonstrated that the proposed algorithm can achieve higher CDN cost savings compared to the conventional algorithm where peers are selected at random.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.401.2-401.2
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• 2002

To study the pharmacokinetics of triflusal, more reliable and sensitive analytical method of triflusal in plasma sample was developed. Analytical method of triflusal in human plasma was developed using semi-microbore HPLC equipped with automated column switching system. p- Toluic acid, which is structural analogue of triflusal. was used as an internal standard and 2 M HCI was employed as a stabilizer. The load phase and mobile phase were prepared using acetonitrile and 20 mM $KH_{2}PO_{4}$ with the volume ratios of 10:90 (pH 2.5) and 43:57 (pH 2.3), respectively. (omitted)

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.2
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• pp.103-109
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• 2006

In this paper, the detection scheme of the spatial coordinates based on stereo camera for a intelligent path planning of an automatic mobile robot is proposed. In the proposed system, face area of a moving person is detected from a left image among the stereo image pairs by using the YCbCr color model and its center coordinates are computed by using the centroid method and then using these data, the stereo camera embedded on the mobile robot can be controlled for tracking the moving target in real-time. Moreover, using the disparity mad obtained from the left and right images captured by the tracking-controlled stereo camera system and the perspective transformation between a 3-D scene. and an image plane, depth information can be detected. Finally, based-on the analysis of these calculated coordinates, a mobile robot system is derived as a intelligent path planning and a estimation.

• Nutrition Research and Practice
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• v.10 no.3
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• pp.342-351
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• 2016

BACKGROUND/OBJECTIVES: This study aims to develop a mobile nutritional management program for integration into the already developed web-based program, Diabetes Mellitus Dietary Management Guide (DMDMG) for diabetic patients. Further, we aim to evaluate the amended DMDMG program. SUBJECTS/METHODS: The mobile application based on an Android operating system includes three parts: 1) record of diet intake, which allows users to take pictures of the meal and save to later add diet records into DMDMG; 2) an alarm system that rings at each meal time, which reminds users to input the data; 3) displays the diet record and the results of nutrient intake, which can be also viewed through the web program. All three parts are linked to the web-based program. A survey was conducted to evaluate the program in terms of nutrition knowledge, dietary attitude, eating behavior and diet intake by non-equivalent control group design among diabetic patients with 14 DMDMG users and 12 non-user controls after a one-month trial of DMDMG. RESULTS: Non-users did not use the program, but participated in the weekly off-line nutrition classes for one month. The program users showed increased healthful dietary behavior (P < 0.01) and dietary attitude scores (P < 0.05). More DMDMG users had higher nutrition knowledge scores after one-month trial than non-users. However, dietary intake significantly increased in non-user group for calcium and sodium (P < 0.05) while the user group did not show significant changes. CONCLUSIONS: The program has created positive changes in patients' dietary life. All the users were satisfied with the program, although some expressed minor difficulties with an unfamiliar mobile app.

• Journal of information and communication convergence engineering
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• v.11 no.3
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• pp.173-178
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• 2013

To discover objects of interest in unstructured peer-to-peer networks, the peers rely on flooding query messages which create incredible network traffic. This article evaluates the performance of an unstructured Gnutella-like protocol over mobile ad-hoc networks and proposes modifications to improve its performance. This paper offers an enhanced mechanism for an unstructured Gnutella-like network with improved peer features to better meet the mobility requirement of ad-hoc networks. The proposed system introduces a novel caching optimization technique and enhanced ultrapeer selection scheme to make communication more efficient between peers and ultrapeers. The paper also describes an enhanced query mechanism for efficient searching by applying multiple walker random walks with a jump and replication technique. According to the simulation results, the proposed system yields better performance than Gnutella, XL-Gnutella, and random walk in terms of the query success rate, query response time, network load, and overhead.

• Journal of Intelligence and Information Systems
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• v.15 no.1
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• pp.31-50
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• 2009

As the collected information which is static or dynamic is infinite in ubiquitous computing environments, information overload and invasion of privacy have been pressing issues in the recommendation service. In this study, we propose a recommendation service procedure through P2P, The P2P helps customer to obtain effective and secure product information because of communication among customers who have the similar preference about the products without connection to server. To evaluate the performance of the proposed recommendation service, we utilized real transaction and product data of the Korean mobile company which service character images. We developed a prototype recommender system and demonstrated that the proposed recommendation service makes an effect on recommending product in the ubiquitous environments. We expect that the information overload and invasion of privacy will be solved by the proposed recommendation procedure in ubiquitous environment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.131-134
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• 2005

This paper describes the efficient peer-to-peer migration method of Grid service agent on the mobile agent based P-Grid. The migration mechanism for transmitting service agent upon the service request is based on the peer's logic network topology. The network topologies that this system uses are organized as star topology, ring topology and tree topology, and agents are migrated by the master/slave method and serial/parallel method. The migration method of services is chosen based on the execution range and characteristic of the requested service. Also, the entire execution time of service is affected by the performance of peer that is a part of network topology, and the migration order, Therefore, the system monitors the performance of peers, and determines the migration priority based on analyzing and learning history. The system can reduce service execution time efficiently with decisions of migration method for service agent and priority of peers.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.6
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• pp.279-283
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• 2012

In is paper, we design and implement the low power, high speed touch screen controller that calculates and outputs the coordinate of touch point on the touch screen of mobile devices. The system clock is 10HMz, the number of input channels is 21, standby current is $20{\mu}A$, dynamic range of input is 140pF~400pF and the response time is 0.1ms/frame. It contains the power management unit for low power, automatic impedance calibration unit in order to adapt to humidity, temperature and evaluation board, adjacent key and pattern interference suppression unit, serial interface unit of I2C and SPI. The function and performance is verified by using FPGA and $0.18{\mu}m$ CMOS standard process. The implemented touch screen is designed for using in the double layer ITO(Indium Thin Oxide) module with diamond pattern and single layer ITO module for cost-effective which are applied to mobile phone or smart remote controller.

• Journal of Korea Multimedia Society
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• v.6 no.2
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• pp.183-193
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• 2003

The importance of XML data and their database supports in a mobile terminal system is on the increase. It leads to active research for embedded XML database systems. In order to handle in documents, DOM API should be supported. The existing DOM API is not suitable for the embedded system with limited resource because the DOM tree requires a large space on main memory. Considering poor resource of embedded systems, we present persistent DOM which is implemented on Berkeley DB and DOMdbm which manages it.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2003.11a
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• pp.167-172
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• 2003

무선 인터넷 서비스는 디지털화된 정보 및 컨텐츠를 유무선 네트워크를 이용하여 최종 사용자의 핸드폰 또는 PDA와 같은 이동 단말기에 제공하는 서비스라고 정의할 수 있다. 본 논문에서는 이러한 무선 인터넷 기술과 은행업무를 분석하여 모바일 뱅킹시스템을 설계 및 구현하였고, 특히 가상계좌 개념을 이용하여 무선 인터넷 환경에서의 실제적으로 응용 가능한 P2P 뱅킹 시스템에서의 최적 솔루션 모듈을 설계 및 구현하였다.