• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.195-201
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• 1989

Voltage collapse is a serious concern to the electirc utility industry. It is common to associate steady-state stability with the ability of the transmission system to transport real power and to associate voltage collapse with the inability to provide reactive power at the necessary locations within the system. An algorithm to directly calculate the critical point of system voltage collapse was presented by the authors. The method (based on the ordinary power flow equations and explicit requirement of singularity of the Jacobian matrix) is basically one degree of freedom with proper load distribution factors. This paper suggests a modified algorithm to increase the degree of freedom, introducing the nonlinear programming technique. The objective function is a distance measure between the present operating point and the closest voltage collapse point. Knowledge of the distance and the most vulnarable bus from the voltage collapse point of view may be used as a useful index for the secure system operation.

• ETRI Journal
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• 제28권1호
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• pp.84-86
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• 2006

This letter presents a small-sized, high-power single-pole double-throw (SPDT) switch with defected ground structure (DGS) for wireless broadband Internet application. To reduce the circuit size by using a slow-wave characteristic, the DGS is used for the quarter-wave (${\lambda}$/4) transmission line of the switch. To secure a high degree of isolation, the switch with DGS is composed of shunt-connected PIN diodes. It shows an insertion loss of 0.8 dB, an isolation of 50 dB or more, and power capability of at least 50 W at 2.3 GHz. The switch shows very similar performance to the conventional shunt-type switch, but the circuit size is reduced by about 50% simply with the use of DGS patterns.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2005년도 춘계학술발표대회
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• pp.699-702
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• 2005

최근 컴퓨터 성능과 네트워크 속도의 발전은 다양한 형태의 데이터를 유선 혹은 무선 환경상에서 주고 받고 처리할 수 있게 해주고 있다. 또한 일차원적인 텍스트, 이미지, 음성, 동영상뿐만 아니라 다차원 형태의 공간 데이터도 다양한 형태의 서비스로 제공되고 있다. 하지만 공간 데이터에 대한 연구는 공간 데이터 표준, 서비스, 성능적인 측면에 대한 연구만 진행이 되었을 뿐 보안적인 측면에 대한 연구는 미비한 상태이다. 이에 XML 의 보안 기법을 공간 데이터에 적용하여 공간 데이터 자체에 대한 보안 레벨과 암호화를 적용하여 공간 데이터 전송을 위한 보안구조를 제시하고자 한다.

• 스마트미디어저널
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• 제5권4호
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• pp.57-62
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• 2016

본 논문에서는 일반 가정이나 건물 내에서 일종의 바이오센서인 개인건강 디바이스를 이용함에 있어, 각 디바이스들과 이들로부터 개인 생체정보를 수집하는 게이트웨이간 통신 시 환자의 개인정보를 보호할 수 있는 새로운 프라이버시 보호 방법을 제안한다. 제안하는 방법은 이전 [1]에서 제안한 프라이버시 보호 방법보다 추가적인 무결성 보장 및 전송 보안을 통해 훨씬 강건하고 안전하며 국제 표준인 ISO/IEEE 11073-20601[2]을 준수하고 있어 다양한 개인건강 디바이스들에 상호 호환이 가능하다는 장점이 있다.

• 한국공간정보시스템학회 논문지
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• 제3권2호
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• pp.53-61
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• 2001

지리공간 데이터 유통망 구조는 유통망 게이트웨이, 유통노드, 지리공간데이터 서버로 구성된다. 최근 정보통신기술과 네트워크 기술의 발전에 따라 점차적으로 지리공간 데이터 유통망에 대한 보안요구가 높아지고 있다. 본 논문은 지리공간 데이터 유통망 보안을 위하여 지리적으로 분산된 유통시스템에 대한 효율적인 접근 통제방안을 제시하기 위한 방법으로 공개키 기반구조 기술을 이용하여 지리공간데이터에 대한 사용자별 접근 통제방안과 지리공간 데이터의 전송보안을 위한 암호화 방안을 제시한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1628-1636
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• 2008

Construction of concrete slab track is trending to increase gradually in national and international for reduction in track maintenance cost and secure of ride comfort. But elastic pad becomes superannuated due to repeated train operation. After all, it brings change of pad stiffness and it could directly act on track and bridge as load transmission and impact force. In this study, we carried out laboratory test changing pad stiffness after making a model of 15m bridge and laying concrete slab track. Also, we carried out static and dynamic behaviors test(stress, natural frequency, damping ratio, vibrational acceleration, deflection) of bridge and track and experimentally analyzed them by change of elastic pad stiffness on rail fastener.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1272-1277
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• 2004

GPS type portable-alarm-system is composed of satellite receiving equipment, signal transmission equipment, etc. Time errors occur because of the processing methods of the satellite receiving equipment and signal generator, the positional error of GPS itself, etc. With the recent rise of train speed, it becomes very important to secure the stability of portable-alarm-system from time errors, The present study estimated errors caused by the structure of portable-alarm-system, GPS errors. etc., and verified them. In addition, it examined the effects of such errors on portable-alarm-system according to train speed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.575-577
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• 2003

With the deregulation of the power industries in many countries, the trend is towards accommodating more freedom and choice to the market participants and encouraging competition as much as possible in the power market. In this regards, the necessity of market simulation is increasing in order to guarantee a secure and reliable operation of an electricity market. This paper presents the technique of market simulation considering constraints such as energy resource and transmission interface using commercial market simulator.

• ETRI Journal
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• 제35권4호
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• pp.726-729
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• 2013

For secure multimedia communications, existing encryption techniques use an online session key for the key exchange, for which key size is limited to less than 10 digits to accommodate the latency condition caused by user devices only being able to handle low computational loads. This condition results in poor security of recorded encrypted data. In this letter, we propose a packet key scheme that encrypts real-time packets using a different key per packet for multimedia applications. Therefore, a key of a relatively small size can provide after-transmission confidentiality to data of a real-time session.

• 아동학회지
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• 제27권6호
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• pp.69-79
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• 2006

This study investigated intergenerational transmission from mother's attachment representation to infant's attachment pattern and the associations between maternal attachment representation and their childhood experiences. Subjects were forty 12- to 15-month-old infants and their mothers. The Adult Attachment Interview (Main & Goldwyn, 1984) was used to assess mother's attachment representation. The Strange Situation (Ainsworth, 1978) was used to classify infant's attachment relationship. Mothers were classified as autonomous (F), dismissing (Ds), preoccupied (E), or unresolved/disorganized (Ud). Infants were classified as secure (B), insecure-avoidant (A), insecure-resistant (C), or insecure-disorganized (D). Exact A/B/C/D and Ds/F/E/Ud agreement was observed in 30 of 40 dyads(75%). Maternal childhood experiences were related to maternal attachment representation.