• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권7호
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• pp.2338-2353
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• 2015

In this paper, the optimal power allocation algorithm that minimizes the aggregate bit error rate (BER) of the secondary user (SU) in a downlink orthogonal frequency division multiplexing (OFDM) based cognitive radio (CR) system, while subjecting to the interference power constraint and the transmit power constraint, is investigated under the assumption that the instantaneous channel state information (CSI) of the interference links between the secondary transmitter and the primary receiver, and between the primary transmitter and the secondary receiver is perfectly known. Besides, a suboptimal algorithm with less complexity is also proposed. In order to deal with more practical situations, we further assume that only the channel distribution information (CDI) of the interference links is available and propose heuristic power allocation algorithms based on bisection search method to minimize the aggregate BER under the interference outage constraint and the transmit power constraint. Simulation results are presented to verify the effectiveness of the proposed algorithms.

• 유통과학연구
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• 제13권2호
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• pp.5-13
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• 2015

Purpose - In recent years, concerns over privatization have been growing in some public sectors. Privatization in Britain offers lessons for those who have intended to privatize their industry, and in particular, the port industry. Therefore, it is useful for researchers to examine British port privatization in detail, particularly the implications of UK port privatization. Research design, data, and methodology - After reviewing the historical development of the UK port industry, the important factors determining the success of the British port privatization process were identified. The interpretations could be lessons for some other country to consider port privatization in near future. Results - The key factors in relation to port privatization are first, regulation; second, ownership; and third, utilities and operations, which includes autonomy, efficiency, and competitiveness. In addition, the UK port management system is a pure private port system, which has been successful. Conclusions - In Britain, after deciding to privatize the erstwhile public ports, they were fully privatized, focusing on the aforesaid key factors. This offers important lessons for the privatization of other ports in the world.

• 한국유통학회지:유통연구
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• 제3권1호
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• pp.145-158
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• 1998

The selection of proposed sites for the general logistic center of agriculture products would be made the most suitable place by considering the spread of population as real consumers, the prospect of the demand, the expansion of traffic system, the regional, hourly and carring traffic volume and the use of land based urban planning, etc. As the preconsideration, the possible occupant companies have to be selected on the category of business and the district. After posing questions and having interview, several selected regions would be compared and analysed for deciding the most suitable place. The model for the general logistic center of agricultural products must be selected taking key factors approach for choosing key factors at first and referring to many documentary records. And the more, cooperating with the specialists for location selection and making objective questions to concerned companies, the most suitable place is selected by marking high score for the moderate land cost, the low traffic jam, the connection with the back cities and the possible expansion as the general logistic center of agriculture products.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2015년도 제51차 동계학술대회논문집 23권1호
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• pp.271-272
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• 2015

센서 네트워크에서 센서는 제한적인 자원 때문에 다양한 공격으로부터 취약하다. 이러한 공격 중 하나인 허위 보고서 삽입 공격은 불필요한 에너지 소모와 허위 알람을 유발한다. 이 공격의 피해를 줄이기 위한 확률적 투표 여과 기법은 검증 노드를 통해 보고서의 맥들을 검증한다. 그러나 허위 보고서가 검증 노드까지 도달하는 데 불필요한 에너지가 소비된다. 본 논문에서, 우리의 제안 기법은 소스의 다음 노드에 키를 배포하여 허위 보고서 삽입 공격을 효율적으로 감지한다. 따라서 제안 기법은 기존 기법보다 에너지 효율성 향상을 기대할 수 있다.

• 한국전자통신학회논문지
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• 제8권2호
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• pp.329-337
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• 2013

본 논문에서는 자율 주행 자동차의 연구 방향을 결정하기 위한 기관별 개인별 논문 분석을 통한 계량정보 분석을 검토한다. 기관별 개인별 논문 수 분석, 수준 분석, 국제협력연구 네트워크 분석, 핵심 기관과 개인의 Q-L분포를 이용하여 자율 주행 자동차의 연구 동향을 확인한다.

• 조명전기설비학회논문지
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• 제23권11호
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• pp.34-43
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• 2009

SCADA (Supervisory Control and Data Acquisition) system has been used for remote measurement and control on the critical infrastructures as well as modem industrial facilities. As cyber attacks increase on communication networks, SCADA network has been also exposed to cyber security problems. Especially, SCADA systems of energy industry such as electric power, gas and oil are vulnerable to targeted cyber attack and terrorism Recently, many research efforts to solve the problems have made progress on SCADA network security. In this paper, flexible key distribution concept is proposed for improving the security of SCADA network using Multiagent System (MAS).

• 한국정보처리학회논문지
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• 제7권4호
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• pp.1175-1183
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• 2000

Base on the development of mobile communication, the future mobile communication systems were expected to provide higher quality of multimedia services for users than today's systems. Therefore, many technical factors are needed in this systems. Especially these secrecy and the safety would be obtained through the introduction of the security for mobile communication. In this paper, we presents weaknesses and propose required properties in mobile communication. Based on those proposed properties, we propose a new 'call set-up' and 'hand-off' protocol for authentication and key distribution. Also we compare between the proposed scheme and conventional schemes.

• 한국정보처리학회논문지
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• 제7권4호
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• pp.1184-1192
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• 2000

Multicast has communication mechanism that is able to transfer voice, video for only the specific user group. As compared to unicast, multicast is more susceptive to attack such as masquerading, malicious replay, denial of service, repudiation and traffic observation, because of the multicast has much more communication links than unicast communication. Multicast-specific security threats can affect not only a group's receivers, but a potentially large proportion of the internet. In this paper, we proposed the multicast security model that is able to secure multi-group communication in CBT(Core Based Tree), which is multicast routing. And designed the multicast key distribution protocol that can offer authentication, user privacy using core (be does as Authentication Server) in the proposed model.

• Transactions on Electrical and Electronic Materials
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• 제7권2호
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• pp.62-66
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• 2006

Advanced CMP conditioner design requires investigations of key conditioner manufacturing parameters and their effects on pad surface and then wafer performance. In the present investigation, diamond shape, concentration, distribution, and other key manufacturing parameters are considered to improve CMP process stability and conditioner life. Self avoiding random distribution ($SARD^{TM}$) of diamond abrasives has been developed and both numerical simulation and experimental results show very stable and reliable polishing performance.

• Journal of Magnetics
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• 제16권4호
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• pp.413-416
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• 2011

An array of FeCo nanotubes has been successfully fabricated in the pores of porous anodic aluminum oxide (AAO) templates by wetting templates method. The morphology and structure of the nanotube array were characterized by scanning electron microscopy, transmission electron microscopy and x-ray diffraction. The average diameter of the nanotubes was about 200 nm, and the length was more than 10 ${\mu}m$. Vibrating sample magnetometer and superconducting quantum interference device were used to investigate the magnetic properties of the nanotube array. Interaction between the nanotubes has been found to be demagnetizing as expected and the switching field distribution is broad.