• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1116-1119
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• 2009

최근 그룹 통신 분야에서 전통적으로 대표되는 IP 멀티캐스트의 대안기술로서 호스트기반 멀티캐스트 및 P2P시스템은 기존의 IP 멀티캐스트의 단점을 극복하고자 하는 연구이다. 이러한 호스트기반 멀티캐스트는 사용자 중심의 서비스를 제공함으로써 다양한 네트워크 환경에서 누구나 사용자들이 효율적으로 데이터를 공유하게 해주고 있다. 본 논문에서는 이러한 협동 기반의 호스트 멀티캐스트를 사용하여 미디어 서비스를 제공하는 VOD 시스템 전반에 관한 연구를 수행하고 이러한 VOD의 서비스를 고도화 하고자 한다. 보다 구체적으로는 패칭 기법을 사용하여 사용자간의 전달 지연을 최소화 할 수 있는 효율적인 자료 전송 경로를 설정 방법과 주문형 비디오 서버를 위한 현실적인 호스트 기반 멀티캐스트 트리 구성 모델을 제시하고자 한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.51-55
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• 2015

In this paper, we proposed scheme that obtain diversity gain in the cooperative communication to mitigate, applied to the effects of fading in the vehicle communication. Relay used bus that can available in the city environment. In addition, we applied the double rayleigh fading environment so that can applied in real-environments. Therefore, proposed scheme through this paper applied to vehicle communication, user can acquire a high quality service and the operation efficiency of the network is improved. Finally, performance of the proposed protocol is analyzed in terms of bit error rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7B
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• pp.664-672
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• 2002

This paper analyzes a sequential estimator with flexible structure for rapid acquisition of the m-sequence signals. If the received PN chips stored in the estimator's internal registers as initial loading values include one error, this chip with error can be corrected through multiple local PN code generators to achieve high-speed acquisition performance. Hamming distance between regenerated local PN codes from the proposed system and received PN code is compared with given threshold to choose a possible correct path and to declare success of the code acquisition. Using signal flow graph, average acquisition time that depends on detection and false alarm probability is calculated. By modifying generally used matched filter structure for PN code acquisition, the proposed system provides flexible structure and rapid acquisition process.

• Convergence Security Journal
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• v.12 no.3
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• pp.35-43
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• 2012

The explosive growth of Internet traffic cause by smart equipment such as smart phone has led to a dramatic increase in demand for data transmission capacity and network control architecture, which requires high transmission rates beyond the conventional transmission capability. Next generation networks are expected to be controlled by Generalized Multi-Protocol Label Switching(GMPLS) protocol suite and operating at multiple switching layers. In order to ensure the most efficient utilization of multilayer network resources, effective global provisioning that providing the network with the possibility of reacting in advance to traffic changes should be provided. In this paper, we proposes a new path selection scheme in multilayer optical networks based on the vertical PCE architecture and a different approach to efficiently exploit multiple PCE cooperation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.853-858
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• 2019

One of the methods which can enhance the efficiency of railroad network is construction of interconnection branch line for several route to share one railway. In Korea, this method already has been implemented or excuted as project level. This study suggests a network design model and a solution algorithm to choice most proper site to construction it and determine the priority of branch lines which can be considered in planning level, not project level. The model is a non-linear optimization program which minimize total cost-construction cost, operating cost and passengers' travel cost. The decision variables are a binary variable to explain whether construction or not and its direction and a integer variable of the frequencies of travel routes. The solution algorithm-problem solution and route choice and also the result of implementation for example network are suggested. This result can be more advanced after application in real network and calibration of parameters.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.327-327
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• 2010

자동차에서 실내음질은 구매결정 요소들 중의 하나로 그 중요성이 점차 증가하고 있다. 따라서 다양한 운전조건에서 운전자가 기대하는 실내음질의 기대 수준을 충족시켜야 한다. 소비자는 운전경험과 습관에 따라 기대하는 음질에 차이가 있고 소리에 대한 표현방식도 모호하기 때문에 이러한 주관적 특성을 하나의 통일된 표현으로 정의 하기가 어렵다. 그러나 지난 이십여 년 동안의 음질개발과 차량 실내소음 주관평가의 통계처리로 통일된 표현을 할 수 있었다. 나아가 심리음향학 및 신호처리기술의 발달과 꾸준한 음질연구결과로 소리특성을 객관적으로 나타내는 소리의 시각화가 가능하였으며, 운전자가 인식하는 주관평가와의 상관관계를 높여 차량의 대표적인 음질인자로 정량화하여 음질목표를 설정할 수 있었다. 실내소음의 구성은 엔진 투과음, 흡배기 소음, 바람 소음, 도로 기인 소음 등으로 다양하므로 소음원에 따라 음의 균형을 맞추어 조화로운 음질개발을 하는 것이 중요했다. 또한 차량 판매되는 지역에 따라 선호음이 상이하여 지역별 실내음질의 차별화가 필요했다. 궁극적으로는 운전자의 감성품질을 만족할 수 있도록 음을 제어하여 브랜드 사운드를 개발하고 있다. 이러한 실내음질을 달성하기 위한 방법으로 소음원과 전달경로에 대해 기여도를 분석하고, 경로를 구성하는 시스템 별로 세분화하여 시스템 목표를 설정하였다. 시스템 개발에 중요한 인자로 차량의 동강성 및 흡차음 성능을 들 수 있다. 특히 디젤차량의 비중이 큰 유럽업체의 차량의 동강성 및 흡차음 개발 능력은 높게 평가되고 있다. 이에 유럽의 부품전문회사가 가지고 있는 해석과 시험적인 개발 방법을 통하여 전달계 특성을 만족하기 위한 시스템의 동강성 및 흡차음 특성을 개발하고 있다. 차량음질 튜닝의 중요한 기법 중 하나로 흡배기 개발을 추진하고 있다. 친환경자동차인 하이브리드차량, 전기차량 및 연료전지차량의 경우 전기구동부품에서 발생하는 각종 이음 발생을 최소화 했다. 보행자를 보호하고 운전의 즐거움을 향상하기 위한 가상사운드 개발을 진행하고 있다. 회사 수익성 향상을 위한 원가절감 및 구조 경량화에 따른 음질악화와 연비 향상 및 배기가스 규제 강화로 고성능 고출력 엔진탑재에 따른 음질악화 요인을 극복해야 했다. 운전자의 청감은 차량의 운전성에 따라서도 크게 영향을 받게 되므로 엔진제어와 변속기제어를 통해 음질과 운전성이 조화를 이룰 수 있도록 개발하고 있다. 향후, 소음원에 따른 시스템 최적화 개발, 운전성과 음질 연계 개발과 친환경차량의 가상사운드 개발 등이 자동차 음질 개발의 중요한 이슈로 생각한다.

• Cartoon and Animation Studies
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• s.36
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• pp.553-572
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• 2014

In this paper, for the evaluation of the ease of a particular Web site (www.appbelt.net), insert the log tracking code for Google Analytics in a page of the Web site to collect behavioral data of visitor and has studied the improvement measures for the problems of the Web site, after the evaluation of the overall quality of the Web site through the evaluation of Coolcheck. These findings set the target value of the company's priority (importance) companies want to influence the direction of the business judgment are set up correctly, and the user's needs and behavior will be appropriate for the service seems to help improvement.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.8B
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• pp.1421-1425
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• 1999

A restoration scheme is presented when a failure occurs at nodes or links on the ATM network. Each node on the network contains the same topology information for resources on the network by Exchanging NSE(Network State Element) which has the network state information through RCC(Routing Control Channel). We also propose a new establishing algorithm that set up a new alternate path reflecting the state of the network changed dynamically at the source node. In the result of applying our scheme, the rates of restoration can be improved and the number of messages decreased so that fast recovering could be possible by reducing traffics on the network by lowering the rates of the call-setup failure at the stage of CAC(Connection Admission Control).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5B
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• pp.260-267
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• 2008

As pervious the SAR(Security Aware Routing)[10] protocol is an secure Ad Hoc network protocol that finds a secure path, it is the security routing protocol that uses the security level of nodes as the routing information. However, the SAR protocol sometimes transfers data through inefficient transmission paths because it always tries to find secure nodes for a safe transmission. Since it is a protocol based on AODV[6], it will cause transmission delay as researching of security routing path. when a node is out of the data transmission range as its battery dying or movement. Although it is possible to connection of nodes because a characteristic of the SAR protocol, the connection is not easy to reconnect when the security level of intermediate node is lower than the level requested by a source node. In this paper, we suggest the MP-SAR based on the SAR to solve the SAR protocol's problem. The MP-SAR seeks multiple secure path for maintenance of data confidentiality using the expanded secure path detection techniques based on the SAR. It can transfer data quickly and reliably by using the shortest efficient path among multiple paths. In the research result, we proved a outstanding performance of MP-SAR than the previous SAR through comparison and analysis.

• Journal of Digital Contents Society
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• v.17 no.3
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• pp.181-188
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• 2016

Video streaming traffics which are arrived in receiver have irregular traffic patterns by many problems over the network path. Particularly, if these received traffics enter into replay buffer without any operation, the overflow and underflow effects are made according to the buffer status. There was an existing scheme which automatically set up token bucket parameters using the video information file under the assumption of the lossless packet on network. The existing scheme has a problem which can set up the wrong token bucket parameters by the lost packets on the practical networks with video packet loss. Therefore, this paper proposes a new scheme which reset up video file information to correct the wrong token bucket parameters in case of packet loss in practical networks with packet loss. Through the simulation, it was found that the proposed scheme would have better performance than the existing scheme in terms of overflow generation and packet loss.