• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권10호
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• pp.3810-3830
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• 2015

In this paper, we investigate the differential game theoretic approach for distributed dynamic cooperative power control in cognitive radio ad hoc networks (CRANETs). First, a payoff function is defined by taking into consideration the tradeoff between the stock of accumulated power interference to the primary networks and the dynamic regulation of the transmit power of secondary users (SUs). Specifically, the payoff function not only reflects the tradeoff between the requirement for quickly finding the stable available spectrum opportunities and the need for better channel conditions, but also reveals the impact of the differentiated types of data traffic on the demand of transmission quality. Then the dynamic power control problem is modeled as a differential game model. Moreover, we convert the differential game model into a dynamic programming problem to obtain a set of optimal strategies of SUs under the condition of the grand coalition. A distributed dynamic cooperative power control algorithm is developed to dynamically adjust the transmit power of SUs under grand coalition. Finally, numerical results are presented to demonstrate the effectiveness of the proposed algorithm for efficient power control in CRANETs.

• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3695-3702
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• 2022

South Korea, a country that built a world-class nuclear power infrastructure, shifted to a nuclear phaseout during the previous government's reign. This shift was pursued as part of a larger task of electricity mix reform, and one of the integral motives for such reform is addressing greenhouse gas (GHG) and fine dust problems. Thus, verifying the relationships between the public's concerns about GHG/fine dust and their acceptance of nuclear power generation is essential for designing public communication strategies to revive nuclear power under the ongoing environmental regime. Our analysis using a nationwide survey sample of South Korea (N = 1009, through proportionated quota sampling method) showed that the more people are concerned about GHG and fine dust, the less they accept nuclear power. These relationships held even after controlling for the effect of a third variable-energy-related environmentalism. This finding means that despite past communication efforts positioning nuclear power as a generation source that can mitigate GHG/fine dust emissions and the widely accepted scientific evidence that supports such positioning, nuclear power in Korea is in jeopardy. Our finding provides implications for public communications and fundamental knowledge for research on the determinants of nuclear power acceptance.

• 융합보안논문지
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• 제13권5호
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• pp.129-135
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• 2013

개정 경비업법은 폭력사태를 근절하기 위하여 31개 조문 중에서 17개 조문을 개정하였다. 개정 경비업법의 주요내용은 허가요건의 강화, 의무의 강화, 집단민원현장의 관리 강화, 임원, 경비지도사 및 경비원의 결격사유 확대, 복장 및 장비, 차량, 관리감독의 강화, 처벌의 강화 등이다. 그러나 개정 경비업법은 배치전 신임교육의 의무화, 용역업체폭력의 원인제공자 처벌, 경비업체에 대한 경찰의 인식, 과도한 규제, 처벌강화의 문제, 경찰의 지나친 감독권 강화 등의 문제가 있다. 이를 해결하기 위해서는 개인부담 교육수료 방안, 집단민원현장이외는 사전교육 의무의 배제, 경비업법의 재개정, 추가부담금의 정부부담, 폭력요구 도급업자의 처벌, 경비원자격증제의 도입 등이 필요하다고 생각한다.

• 한국콘텐츠학회논문지
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• 제9권11호
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• pp.325-334
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• 2009

현대사회에서 CCTV는 현대인의 생활속에 자리잡으면서, 공적장소뿐만 아니라 사적장소에서 설치의 확대가 되고 있는 추세이다. CCTV의 범죄예방의 효과에 대한 논쟁은 있지만 여러 학자들의 선행연구결과를 보면 CCTV의 범죄예방의 긍정적인 부분이 많은 것으로 나타나고 있다. 범죄는 시민들의 일상생활에서 공포와 두려움의 대상이 되기 때문에 이러한 범죄문제를 해결하지 않으면 시민들의 삶의 질도 개선되지 못 할 것이다. 우리사회에서 발생하는 다양한 위험요인 중 주택가나 시설물, 도로 등에서 발생하는 범죄는 시민들의 안전한 삶을 위협하는 심각한 요인으로 작용하고 있다. 범죄로부터 안전한 지역사회를 조성하는 일은 경찰뿐만 아니라 지방자치단체, 지역주민이 함께 노력해야 하는 문제이다. 본 연구는 다양한 CCTV의 활용부문 중에서 가로 및 주택가의 방범용 CCTV의 설치를 위한 진단 Program을 개발하는데 목적이 있다.

• 수산해양기술연구
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• 제52권2호
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• pp.162-168
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• 2016

This study attempted to help determine Korean fishery policies by proposing improvement plans after examining the current regulations, fishing vessels, fishing gear and fishing methods of the middle sized trawl fishery in the East Sea for targeting only squid. In general, the size, engine horse power, and net length of the middle sized trawlers are between 50 and 60 GT, 1,200 and 1,600 PS, and approximately 165 m with four seamed trawl nets, respectively. While a jigging vessel attracted squids using lights, the trawler approached a jigging vessel. The trawler let the jigging vessel know its decision for fishing, and then jigging vessel rolled up jigs. The net of the trawler was casted at 45 degrees between the bow and the stern of the jigging vessel. Once the trawler towed close to the stern of the jigging vessel upon its passing of the jigging vessel, the bow of the trawler turned 45 degrees left again. Then, squid aggregations were entered into the net. When the cod end was passed a light vessel, the trawler hoisted the net up to the otter board. Then the trawler turned 180 degrees. It repeated three to five times of fishing operations as the previous method. We recommend that the regulations allow nineteen side trawlers to catch like stern trawler, as well as the cooperative trawler and jigging vessel operations.

• International Journal of Contents
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• 제7권3호
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• pp.71-81
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• 2011

This paper is mainly associated with setting out an agenda for the transformation of security by creating a new framework for a security system, which can maximise its effectiveness. Noticeably, this research shows empirically that crimes are getting a major cost to organisations, which if reduced by security and investigations could reap substantial rewards to the finances of an organisation. However, the problem is that the delivery of security is frequently delegated to personnel (e.g. security guards) with limited training, inadequate education, and no real commitment to professionalism - 'sub-prime' security, finally causing security failures. Therefore, if security can be enhanced to reduce the crime cost, this will produce financial benefits to business, and consequently could produce a competitive advantage. For this, the paper basically draws upon Luke's theoretical framework for deconstructing 'power' into three dimensions. Using this three-dimensional approach, the paper further sets out a model of how security can be enhanced, utilising a new Security Risk Management (SRM) model, and how can this SRM model create competitive advantage in business. Finally, this paper ends with the six strategies needed to enhance the quality of security: refiguring as SRM, Professional Staff, Accurate Measurement, Prevention, Cultural Change, and Metrics.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2008년도 춘계학술발표논문집
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• pp.224-227
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• 2008

사용자가 안전한 WiBro 서비스를 받기 위해서 사용자 단말과 ACR(Access Control Router) 간에 인증이 선행되어야 한다. 그렇지 않을 경우, 많은 공격 위험으로부터 노출될 수 있다. 따라서 한국정보통신기술협회(TTA)에서는 휴대인터넷(와이브로$^{TM}$) 서비스를 위한 상호 인증 절차 표준을 제정하였다. 이 표준 프로토콜은 PISIM(Portable Internet Subscriber Identity Module)을 이용하여 PE(Portable Equipment)와 ACR 간에 상호 인증을 수행한다. 그러나 표준은 인증에 필요한 메시지의 수가 대체적으로 많은 편이며 PISIM의 분실과 에러가 발생했을 경우에는 사용자는 무선인터넷 서비스를 사용할 수 없게 된다. 따라서 본 논문에서는 ACR과 PSS 간에 키 동의 프로토콜을 수행하여 PSS를 인증한다. 이때 PSS의 계산량을 지원하기 위한 PSD(Power Support Device)가 키 동의 프로토콜에 참여하게 된다. 이렇게 생성된 키는 ACR과 안전한 통신 세션을 맺고 있는 KAS(Key Authentication Server)에 PSS의 식별자와 키 정보를 암호화에서 저장한다. 끝으로 제안된 프로토콜의 안전성과 효율성을 분석한다.

• 한국해양공학회지
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• 제24권4호
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• pp.72-77
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• 2010

This paper presents a method for measuring the shaft power of a marine main engine. Usually, in traditional systems for measuring shaft power, a strain gauge is used even though it has several disadvantages. First, it is difficult to set up the strain gauge on the shaft and acquire the correct signal for analysis. Second, it is very expensive and complicated. For these reasons, we investigated alternative approaches for measuring shaft power and proposed a new method that uses a vision-based measurement system. For this study, templates for image processing and CCD cameras were installed at the both ends of the shaft. Then, in order for the cameras to capture the images synchronously, we used a trigger mark and a optical sensor. The position of each template between the first and the second camera images were compared to calculate the torsion angle. The proposed measurement system can be installed more easily than traditional measurement systems and is suitable for any shaft because it does not contact the shaft. With this approach, it is possible to measure the shaft power while a ship is operating.

• 동력기계공학회지
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• 제16권3호
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• pp.64-68
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• 2012

Because the magnetic bearing supports levitating body without contact, wear, noise and vibration are very small comparing with mechanical bearings, it is very useful to high revolution machinery. In general, the magnetic attractive force function that is proportional to square of control current(x), and inversely proportional to square of an air gap(i) has been widely used. This paper proposed the new magnetic attractive force function that is proportional to cube of the control current, and inversely proportional to square of the air gap. The function was optimized to minimize the cost function that is the percentage of deviation about the change of a proportional constant(k), using the experimental data, ie, control currents and air gaps.

• 동력기계공학회지
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• 제16권3호
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• pp.16-21
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• 2012

Biodiesel is technically competitive with or offers technical advantages over conventional petroleum diesel fuel. Biodiesel is an environmentally friendly alternative liquid fuel that can be used in any diesel engine without modification. In this study, to investigate the effect of fuel injection timing on the characteristics of performance with DBF in DI diesel engine. The engine was operated at five different fuel injection timings from BTDC $6^{\circ}$ to $14^{\circ}$ at $2^{\circ}$ intervals and four loads at engine speed of 1800rpm. As a result of experiments in a test engine, maximum cylinder pressure is increased with leading fuel injection timing. Specific fuel oil consumption is indicated the least value at BTDC $14^{\circ}$ of fuel injection timing.