• Korean Journal of Radiology
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• 제23권10호
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• pp.986-997
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• 2022

Objective: Whether metabolic redistribution occurs in patients with white matter hyperintensities (WMHs) on magnetic resonance imaging (MRI) is unknown. This study aimed 1) to propose a measure of the brain metabolic network for an individual patient and preliminarily apply it to identify impaired metabolic networks in patients with WMHs, and 2) to explore the clinical and imaging features of metabolic redistribution in patients with WMHs. Materials and Methods: This study included 50 patients with WMHs and 70 healthy controls (HCs) who underwent ¹⁸F-fluorodeoxyglucose-positron emission tomography/MRI. Various global property parameters according to graph theory and an individual parameter of brain metabolic network called "individual contribution index" were obtained. Parameter values were compared between the WMH and HC groups. The performance of the parameters in discriminating between the two groups was assessed using the area under the receiver operating characteristic curve (AUC). The correlation between the individual contribution index and Fazekas score was assessed, and the interaction between age and individual contribution index was determined. A generalized linear model was fitted with the individual contribution index as the dependent variable and the mean standardized uptake value (SUV_mean) of nodes in the whole-brain network or seven classic functional networks as independent variables to determine their association. Results: The means ± standard deviations of the individual contribution index were (0.697 ± 10.9) × 10^-3 and (0.0967 ± 0.0545) × 10^-3 in the WMH and HC groups, respectively (p < 0.001). The AUC of the individual contribution index was 0.864 (95% confidence interval, 0.785-0.943). A positive correlation was identified between the individual contribution index and the Fazekas scores in patients with WMHs (r = 0.57, p < 0.001). Age and individual contribution index demonstrated a significant interaction effect on the Fazekas score. A significant direct association was observed between the individual contribution index and the SUV_mean of the limbic network (p < 0.001). Conclusion: The individual contribution index may demonstrate the redistribution of the brain metabolic network in patients with WMHs.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 V
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• pp.2537-2540
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• 2003

In this paper, an integrated monitoring system is implemented for industrial equipments which use different types of network protocols to communicate with other equipments. Dedicated gateway systems mate it difficult to modify or to add contents of network systems for communication with other systems. We suggest an integration method of effectively utilizing the general purpose gateway system (ETOS-l00A) which converts various types of protocols into TCP/IP protocol. To demonstrate the validity of the proposed integrated monitoring system, PLC-based automated inspection system is considered and the monitoring system is implemented using Visual Basic and HMI software.

• 전기전자학회논문지
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• 제13권2호
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• pp.108-117
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• 2009

In recent years, one of alternatives for constructing RFID networks that provide mobile services is using wireless sensor networks (WSN) to enhance network capacity, utility and scalability. Due to absence of compatible reader anti-collision control and channel capture phenomenon, the medium access control protocols as used in the RFID networks lead to reader collision and starvation problem. In this paper, we develop a MAC protocol which is called Enhanced Collision Avoidance MAC (ECO) to avoid reader to reader collisions in an integrated RFID network. ECO is a CSMA-based MAC protocol, and operates on integrated nodes which consist of a RFID reader and a mote. Performance evaluation shows superior results to pure-CSMA protocols under dense deployment environments, both in number of failures and in throughput.

• Journal of electromagnetic engineering and science
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• 제18권3호
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• pp.160-168
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• 2018

A wide spectrum of potential applications using substrate integrated waveguide (SIW) technologies in conjunction with air hole regions is introduced, and an efficient optimization methodology to cope with the multiple air hole effect in SIW applications is proposed. The methodology adopts a genetic algorithm to obtain optimum air hole dimensions for the specific propagation constant that can be accurately calculated using the recursive and closed form equations presented. The optimization results are evaluated by designing an SIW bandpass filter, and they show excellent performance. The optimization methodology using the proposed equations is effective in performance enhancement for the purposes of low loss and broadband SIW applications.

• 한국멀티미디어학회논문지
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• 제17권6호
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• pp.687-696
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• 2014

An integrated ship area network has functionality of remote control and autonomous management of various sensors and instruments embedded or boarded in a ship. For such environment, an wireless bridge is essential to transmit control and/or managing information to sensors or instruments from a central integrated ship area network station. In this paper, one of reliable schemes of WiMedia based wireless bridge using relay cooperative transmission using WiMedia distributed MAC protocol is proposed to increase a communication reliability between cluster headers, irrespective of channel variation. Simulation results show that the proposed wireless bridge using relay cooperative transmission scheme increases communication reliability.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.1182-1185
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• 1995

This paper presents a novel technology for unattented continuous monitoring of radioactive material in hot cell environments. In this monitoring system, the surveillance camera data and NDA data are time synchronized and integrated into the same dimension through data processing. The integrated information is then fed into a neural network to generate diagnostics through data processing. the integrated information of the concept is tested for a spent nuclear fuel transprotation in an operational hot cell at KAERI. The presented integral part of the multi-sensory system and the analytical paradigm may provide an effective technologyical alternative for safeguarding new conceptual hot cell facilities, namely the Dupic facility.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2000년도 봄 학술발표논문집 Vol.27 No.1 (A)
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• pp.322-324
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• 2000

본 논문에서는 이동 컴퓨팅 환경에서 이동 호스트에게 실시간 서비스의 Quality of Service(QoS)를 제공하기 위한 자원 예약 프로토콜을 제시, 설명한다. 실시간 서비스를 제공하는데 있어 이동성은 통신 경로의 변경으로 인해 QoS에 심각한 영향을 끼치게 된다. 그러나 현재 QoS를 위한 signaling 프로토콜인 자원 예약 프로토콜(Resource ReServation Protocol , RSVP)은 고정 호스트만을 가정하고 있으므로 이동 컴퓨팅 환경에서 그대로 사용하기에는 적합하지 않다. 이에 본 논문에서는 이동 호스트를 지원하는 Integrated Network에서 RSVP Agent를 사용하여 Mobile IP와 연동하는 새로운 signaling프로토콜을 제안한다. RSVP Agent는 RSVP tunnel을 사용하여 이동호스트를 대신해서 주위의 ？들에 미리 자원을 예약해 주는 역할을 하게 된다. 이 후 이동 호스트는 RSVP Agent가 미리 예약해준 자원을 사용하게 됨으로써 고정 호스트에게 상대 노드의 이동성을 고려하여 자원을 예약하지 않아도 되도록 지원해주며, 경로 마다 관리해야 하는 soft-state 유지비용의 감소를 가져오고, 불필요한 bandwidth의 예약을 막고, 패킷 지연을 줄여 주는 효과를 가져오게 되며 그 결과를 시뮬레이션을 통하여 확인해 본다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2174-2177
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• 2003

Internet is exposed to network attacks as Internet has a security weakness. Network attacks which are virus, system intrusion, and deny of service, put Internet in the risk of hacking, so the damage of public organization and banking facilities are more increased. So, it is necessary that the security technologies about intrusion detection and controlling attacks minimize the damage of hacking. Router is the network device of managing traffic between Internets or Intranets. The damage of router attack causes the problem of the entire network. The security technology about router is necessary to defend Internet against network attacks. Router has the need of access control and security skills that prevent from illegal attacks. We developed integrated security management framework for secure networking and kernel-level security engine that filters the network packets, detects the network intrusion, and reports the network intrusion. The security engine on the router protects router or gateway from the network attacks and provides secure networking environments. It manages the network with security policy and handles the network attacks dynamically.

• 인터넷정보학회논문지
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• 제5권3호
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• pp.87-98
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• 2004

일반 가입자들에게 초고속 인터넷 서비스를 제공하기 위해서 구성되는 가입자 망은ADSL, VDSL, DOCSIS 등 다양한 종류의 접속방식과 그에 따른 이기종(이기종)의 장비들로 이루어져 있다. 이러한 가입자 망은 전국적으로 분산되어 있으며, 분산된 가입자 망은 효과적이며 집중화된 형태로 관리하기 위해서는 다양한 형태의 접속방식을 지원하는 이기종 장비 및 단말들의 상위 개념으로서 추상적이며 논리적인 객체 관리모델이 필요하다. 본 논문은 통합된 계층적 망관리를 가능하게 하는 인터넷 가입자 망에 대한 모델링 구조론 RM-ODP흘 이용하여 제시하였다. 그리고 가입자 망의 예로서 UML을 이용한 객체지향 방법론을 채택하여 DOCSIS의 HFC 가입자망에 대한 관리 시스템을 설계하고 구현하였다.

• 한국정보통신학회논문지
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• 제7권4호
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• pp.678-683
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• 2003

본 연구에서는 컴퓨터 통신망에서 음성/데이터 통합을 위하여 이행단계별 성능평가를 실시하고 최적의 모델을 제안하였다. 먼저 기존에 있는 PBX를 데이터 네트워크에서 수용할 경우3.3ms에서 3.5ms 지연이 발생하였고, IP를 이용한 음성/데이터 네트워크 통합시 0.7ms에서 0.9ms지연이 발생하였다. IP+/ATM를 이용한 음성/데이터 네트워크에서는 0.26ms에서 0.32ms 지연이 발생하였고, 일부 지역 네트워크에 장애를 발생 할 경우 IGRP 라우팅 프로토콜은 1.1ms-1.3ms, OSPF 라우팅 프로토콜은 0.9ms-1.2ms의 지연이 발생하였다. 본 연구에서는 컴퓨터 통신망에서 음성/데이터 통합을 하기 위해서는 음성/데이터 통합망은 IP+ATM를 이용하고, 계층적인 통신망에서 사용하는 라우팅 프로토콜은 OSPF를 사용할 때 최적의 성능을 보장 받을 수 있음을 확인하였다.