• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.581-583
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• 2021

Due to the pendemic of Corona 19, the use of mobile services is increasing. However, since anomalies in most mobile devices are recognized by the device's alarm, it is difficult to intuitively determine the problem of the device when a complex failure occurs. To compensate for this, in this study, the Anomaly Score was created by RRCF algorithm to intuitively recognize the problem by combining the alarm and performance information of the equipment, and the effect of detecting 97% of the past failure history was verified.

• Annual Conference of KIPS
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• 2008.11a
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• pp.1083-1086
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• 2008

유비쿼터스 시대를 맞이하여 기존의 클라이언트-서버 모델을 벗어나 분산된 자원을 활용하는 방법이 연구 중인데 그 중 대표적인 것이 멀티 에이전트 시스템이다. 그러나 멀티 에이전트 시스템은 에이전트를 탐색할 때 깊이 우선 탐색 기법을 사용하는데 이는 에이전트 시스템과 맞지 않는 면이 있어 멀티 에이전트 시스템을 분석하여 탐색을 단축하는 기법을 제안하고자 한다. 본 논문에서는 에이전트 시스템의 에이전트 탐색에 매니저 DF를 두어 확률적으로 탐색확률이 높은 에이전트 플랫폼을 우선탐색 함으로써 에이전트 탐색 성능을 향상시킬 수 있다. 또, 매니저 DF에 네트워크 장애 등의 사고를 대비하여 미리 인접한 DF에 자료를 백업해두어 장애 발생 시에도 백업해 둔 자료를 활용하여 빠르게 그 업무를 대체할 수 있도록 하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.6
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• pp.723-729
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• 2014

When the bluetooth technology of smartphone is applied to a remote control system, communication errors caused by wave attenuation and interference results in the shortening of communication distance, loss of the target device control and malfunctioning. In this study, we propose a method to adopt a retransmission persistence controlled S/W ARQ in bluetooth communication to minimize the effect of the communication failure and to detect and handle the state where the target device gets lost control. We implemented a motor-driven RC car equpped with a bluetooth communication module and a steering application program on smartphone to test the proposed method. The experiments are conducted in three communication environments, and have resulted in the increase of the communication distance by at least 30% when S/W ARQ is applied. Moreover, when the communication was disrupted due to environmental disturbances, the S/W ARQ based system stopped immediately any undergoing operations to avoid possible malfunction.

• The Bulletin of The Korean Astronomical Society
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• v.34 no.1
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• pp.160.1-160.1
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• 2009

• Electronics and Telecommunications Trends
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• v.4 no.4
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• pp.65-77
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• 1989

기술발전에 따라 정보통신용 단말장치들은 거의 모두 디지틀기술에 의존하고 있다. 이 디지틀기술은 복잡, 다양하고 지능적인 기능 처리를 할 수 있도록 해주는 반면 전자파간섭(EMI)이라는 전자파잡음을 발생시켜 무선수신기, TV등에 수신장애를 야기시킨다. 본 고는 무선단말장치를 제외한 단말장치에 대하여 전자파간섭의 국제기술기준을 조사분석하고 그 측정방법을 기술하였다.

• Electronics and Telecommunications Trends
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• v.9 no.1
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• pp.1-10
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• 1994

본 고에서는 전화망에서 발생되는 여러 전송 장애 요인들이 팩시밀리 통신에서 화상에 어떤 영향을 주는지 각 파라미터에 대하여 측정하였다. 이 연구에서 선정된 주요 파라미터는 최근의 측정 결과를 바탕으로 하였다. 이러한 파라미터들은 전송 선로의 특성에 따른 감쇠 왜곡, 군지연 왜곡 등과 그 외에 임펄스성 잡음, 위상지연, 위상 히트 등이다. 이 파라미터들은 모두 팩시밀리 화상 품질에 영향을 주고 있으므로 일정 수준의 팩시밀리 품질을 유지하기 위해서는 영향을 주는 파라미터를 관리하여야 한다.

• Journal of KIISE:Information Networking
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• v.27 no.2
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• pp.187-196
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• 2000

Failures in ATM networks can occur at virtual path (VP) links, virtual path switches, and virtual channel (VC) switches. Restoration schemes have been proposed for VP link and VP switch failures, however, none for VC switch failures. In general, VC switches are used for edge nodes in protection domains. Since even only one VC switch failure can cause a critical problem, new restoration schemes for VC switch failures are highly required. Restoration schemes at the VP level proposed so far can be categorized into those using the flooding algorithm and those using the backup virtual path (BVP) concept. Even though the latter cannot handle unpredictable failures, it has some advantages such as fast restoration and low spare capacity requirement. In this paper, we propose new restoration schemes using a new type of BVPs to handle VC switch failures. The simulation results show that the proposed schemes can restore virtual connection failures due to VC switch failures without degrading restorability for VP failures.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.701-712
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• 2012

The concept of $k$-shortest disjoint paths is considered important because the establishment of primary and backup forwarding paths exploiting shorter distance and faster propagation time is a dominant consideration for the design of a survivable backbone network. Therefore, we need to evaluate how well the concept of $k$-shortest disjoint paths is exploited for the design of a survivable ship backbone network considering the international standard related to ship backbone networks, the IEC61162-410 standard specifying how to manage redundant message transmissions among ship devices. Performance evaluations are conducted in terms of following objective goals: link capacity, hop and distance of primary and backup paths, even distribution of traffic flows, restoration time of backup forwarding paths, and physical network topology connectivity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.3
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• pp.689-696
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• 2015

In this study, a learning system based on smart learning is proposed so that students with learning disabilities can learn the effective use of meta-cognitive to solve problems arising during the learning process. The features of the proposed system are as follow. First, it is possible to achieve students' individualized learning by use of smart devices and smart education system. Second, it is possible to provide the constant repetition learning for students. Third, students can improve their achievement using the proposed app. The proposed smart education system using meta-cognition was applied to some learning disabilities students. The following results were obtained. First, the disabled students could have an interest in learning math and improve confidence. Second, the student's mathematical problem-solving skills have improved. Third, students' individualized and self-directed learning was achieved.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.256-259
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• 2011

Smart phones mixed with mobile devices and computers are biggest change of information technology and user-installed applications of them provide various information and services which were only possible on PC and Internet in the past. They are expected to be used by ten million people in 2011 and people with disabilities can get easily information and location of disabled facilities using them. In this paper, we design a mobile information service system for person with disabilities, which provides various information and location of disabled facilities. We build information of disabled facilities using acquisition information through existing web sites and provide location based service with user's location.