• 한국습지학회지
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• 제22권1호
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• pp.1-7
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• 2020

비점오염은 수계에 악영향을 끼치며 그 영향은 점차 커지고 있다. 이러한 비점오염을 관리하기 위해 정부에서는 LID(Low Impact Development) 시설의 연구와 다양한 효율평가를 시행하고 있다. 본 연구에서는 다양한 LID 시설 중 실제 설치된 투수 블록 시설의 강우 유출 억제를 위한 유출 저감율, 저류 강우량 분석 및 유출 지연시간 그리고 최대 유입 및 유출의 저감율을 분석했으며, 그 결과를 각 시설 간 비교했다. 불투수블록, 필터형 투수블록, 틈새형 투수블록 순서대로 분석 결과 저감 효율이 높게 나타났으며, 이를 통해 강우강도-유출지연시간간의 관계를 나타낸 그래프를 제시하였다. 이 그래프를 통해 앞으로 설계 시, 본 시설과 유사한 투수블록 시설의 재현 기간에 따른 시설 용량 선정 등의 설계에 도움을 줄 수 있으리라 생각한다.

• 한국해양공학회지
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• 제28권1호
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• pp.20-27
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• 2014

In view of the importance of material reduction and rational structural design due to the rapid increase in oil and steel prices, an optimized structural hybrid design system for the doubler plate of a ship's hull structure was developed. A direct design process by a structural designer was added to this developed optimized system to increase the design efficiency and provide a way of directly inserting a designer's decisions into the design system process. As the first step of the doubler design system development, the design formulas used in doubler design system were introduced. Based on the introduction of influence coefficients $K_{t_c}$ $K_{t_d}$, $K_{b_d}$ and $K_{a_d}$ according to the variations in the doubler length, breadth, doubler thickness, and average corrosion thickness of the main plate, the design formulas for an equivalent plate thickness were developed, and a hybrid design system using these formulas was suggested for the slender doubler plate of a ship structure subjected to a longitudinal in-plane compression load. By using this developed design system, a more rational doubler plate design can be expected considering the efficient reinforcement of the plate members of ship structures. Additionally, a more detailed structural analysis through local strength evaluations will be performed to verify the efficiency of the optimum structural design for the doubler plate.

• Nutrition Research and Practice
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• 제2권3호
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• pp.165-170
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• 2008

Protein-energy malnutrition is regarded as one of the public health problems in developing countries as a result of poor feeding practices due to poverty. This study, therefore, aimed at evaluating nutritional quality of a potential weaning food formulated from locally available food materials. The cooking banana fruit(CB) and bambara groundnut seeds(BG) were purchased from local market in Akure, Ondo State, Nigeria. The CB and BG were processed into flours, mixed in ratios of 90:10, 80:20, 70:30 and 60:40 and subjected into proximate, sensory and biochemical analyses using standard procedures. Nutrend(a commercial formula) and ogi(corn gruel, a traditional weaning food) were used as control. The nutritient composition(g/100 g) of the food samples were ranged as follows: moisture 2.94-6.94, protein 7.02-16.0, ash 1.76-2.99, fat 0.76-8.45, fibre 1.52-3.75, carbohydrate 63.84-88.43 and energy 1569.8-1665.7 kcal. The biological value(BV), net protein retention(NPR), protein efficiency ratio(PER) and feed efficiency ratio(FER) of the experimental food samples were significantly(p<0.05) lower than nutrend, but higher than ogi. The haematological variables of rats fed with formulated food samples, commercial formula(nutrend) and traditional weaning food(ogi) were not significantly(p>0.05) influenced by the dietary treatment. However, the values obtained for red blood cell(RBC), white blood cell(WBC), pack cell volume(PCV) and erythrocyte sedimentation rate(ESR) were higher in the experimental food samples than the commercial food. The growth rate of animals fed with experimental food samples were lower than those fed with the nutrend, but higher than those fed with ogi. In conclusion, the nutritional quality of CB and fermented BG mix of 60:40 ratio was better than ogi; and comparable to the nutrend. This implies that it can be used to replace low quality traditional weaning food and the expensive commercial weaning formula.

• 유기물자원화
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• 제13권2호
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• pp.91-97
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• 2005

본 연구는 종이 다른 여러 가지 미생물을 사용하여 음식물쓰레기 침출수의 악취저감 효과를 가지는 균주를 선별하고자 실시하였다. 침출수에 전배양한 해수미세조류인 Spirulina plantensis 와 Chlorella vulgaris, 효모 Saccharomyces cerevisae와 세균인 Bacillus cereus를 각각 10% 주입하여 총 10일간 배양하였다. 72시간 주기로 pH와 염도, 관능검사를 시행한 결과, pH는 초기에 3.5~4.0 값을 보였으나 시일이 경과함에 따라 4.9~7.4 수준까지 증가하였고, 염도는 Chlorella vulgaris와 Spirulina platensis는 급격히 낮아졌다. 관능평가를 통한 악취시험 결과 광합성 미세조류인 Chlorella vulgaris가 발효 종료일인 10일째 거의 취기를 느낄 수 없는 악취도 1을 나타내어 악취제어에 효과가 있는 것으로 나타났다.

• Journal of Communications and Networks
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• 제11권6호
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• pp.599-606
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• 2009

For many mission-critical related wireless sensor network applications such as military and homeland security, user's access restriction is necessary to be enforced by access control mechanisms for different access rights. Public key-based access control schemes are more attractive than symmetric-key based approaches due to high scalability, low memory requirement, easy key-addition/revocation for a new node, and no key predistribution requirement. Although Wang et al. recently introduced a promising access control scheme based on elliptic curve cryptography (ECC), it is still burdensome for sensors and has several security limitations (it does not provide mutual authentication and is strictly vulnerable to denial-of-service (DoS) attacks). This paper presents an energy-efficient access control scheme based on ECC to overcome these problems and more importantly to provide dominant energy-efficiency. Through analysis and simulation based evaluations, we show that the proposed scheme overcomes the security problems and has far better energy-efficiency compared to current scheme proposed byWang et al.

• 한국통신학회논문지
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• 제32권12B호
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• pp.815-825
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• 2007

IT 중소 벤처기업에 대한 정부자금지원정책 성과를 적시에 객관적으로 평가할 수 있는 체계의 확립이 필요하다. 본 연구는, Data Envelopment Analysis (DEA) 모형을 활용한 IT 중소 벤처기업 정부자금지원정책 성과평가 체계를 제안하고, 실증자료를 이용한 사례분석을 예시한다. 특히, 도출된 최적해 신뢰도 제고를 위해, Acceptance Region (AR) Type I 제약식이 추가된 DEA/AR-I수정모형을 개발한다. 본 모형 및 절차를 활용, 후속 성과평가를 보다 신속히 진행할 수 있게 지원하는 유도지표 (guideline)로서의 '효율성지수' 계산이 가능하다고 판단된다. 'IT SMERP 2010 계획'에 포함된 정부자금지원정책 주요사업을 대상으로, 사업간 및 동일사업내 수혜기업간 성과평가가 논의된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권3호
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• pp.943-961
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• 2020

With the advent of IoT technology and Big Data computing, the importance of WSNs (Wireless Sensor Networks) has been on the rise. For energy-efficient and collection-efficient delivery of any sensed data, lots of novel wireless medium access control (MAC) protocols have been proposed and these MAC schemes are the basis of many IoT systems that leads the upcoming fourth industrial revolution. WSNs play a very important role in collecting Big Data from various IoT sensors. Also, due to the limited amount of battery driving the sensors, energy-saving MAC technologies have been recently studied. In addition, as new IoT technologies for Big Data computing emerge to meet different needs, both sensors and sinks need to be mobile. To guarantee stability of WSNs with dynamic topologies as well as frequent physical changes, the existing MAC schemes must be tuned for better adapting to the new WSN environment which includes energy-efficiency and collection-efficiency of sensors, coverage of WSNs and data collecting methods of sinks. To address these issues, in this paper, a self-organization scheme for mobile sensor networks with mobile multiple sinks has been proposed and verified to adapt both mobile sensors and multiple sinks to 3-dimensional group management MAC protocol. Performance evaluations show that the proposed scheme outperforms the previous schemes in terms of the various usage cases. Therefore, the proposed self-organization scheme might be adaptable for various computing and networking environments with big data.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.301-301
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• 2009

The General program evaluation guide is intended for use by managers of both deployment and R&D programs within the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy (EERE), although most of the examples of evaluations pertain to deployment programs(EERE,2006). It could help managers determine what kinds of timely adjustments may be needed in program design or implementation to improve the rate or quality of achievement relative to the committed resources. To consider the adaptation of the method in Korea, we have studied the evaluation case for solar america initiative using cost-benefit evaluation. The President's Solar America Initiative (SAI) was launched in January 2006 as part of the administration's Advanced Energy Initiative. The SAI has a goal of installing 5-10 GW of photovoltaic (PV) systems in the U.S. by 2015 and 70-100 GW of PV systems in the U.S. by 2030. The evaluation report presents estimates of the potential benefits should the SAI PV installation goals be achieved. For this analysis, the areas researched include energy, economic, and environmental benefits. As a result, research suggests that 500 MW of PV may have been enough to avoid lackout. The ability of PV to prevent specific blackouts will depend on very specific information on where the PV installations are installed and their ability to relieve pressure on the high stress points on the grid. While this level of detail is outside the scope of this study, it appears that there will be some potential benefit for blackout prevention should the SAI PV goals be achieved.

• 한국방사선학회논문지
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• 제1권1호
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• pp.31-37
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• 2007

본 연구의 목적은 CR(Computed Radiography)과 DR(Digital Radiography)장비의 각 Detector를 통해 획득된 영상의 화질을 비교 분석하기 위한 것이다. CR(AGFA MD 4.0 General plate, JAPAN)과 DR(HOLOGIC nDirect Ray, USA)에 대한 영상평가의 주요인자인 MTF(Modulation transfer function), NPS(Noise power spectrum), Photon fluence, DQE(Detective quantum efficiency)를 정량적인 값으로 도출하여 비교한 결과 CR이 DR보다 우수하게 나타났다. 본 연구의 결과는 CR과 DR장비의 Image quality를 정량적으로 평가할 수 있을 뿐만 아니라 이 장비들을 유지, 보수하는데도 도움이 될 것으로 사료된다.

• 한국컴퓨터정보학회논문지
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• 제13권4호
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• pp.213-220
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• 2008

본 논문에서는 국가자격종합관리시스템 구축 및 운영의 효율성을 향상시키기 위하여 외부위탁 관리시스템과 연계한 실시간 자료공유 시스템을 설계하고 개발하였다. 현재까지 대부분의 국가자격 종합관리시스템은 IT 전문기업에 개발, 구현, 운영에 대한 전반적인 사항을 위탁으로 수행한 후, 처리 결과에 대한 정보를 인수받아 업무를 처리하였다. 이러한 처리방식은 전체적인 정보에 대한 재처리, 기능추가, 시스템 안정성 등에 많은 문제점을 가지고 있다. 제안된 실시간 자료공유 시스템의 성능평가를 위하여 기본적 시뮬레이션으로 파일럿시스템에서 제안 기술을 적용하여 검증 한 후 대한상공회의소 실시간 국가기술자격 시험에 적용한 결과 안정성이 입증되어 지방상공회의소까지 지속적으로 확대 적용할 계획이다. 국가자격종합관리 실시간 자료공유 시스템은 정보재처리와 부가기능 추가시 발생되는 개발기간에 대한 문제를 근본적으로 해결하였으며 안정적 시스템운영 상태와 최대 효율성을 보여주었다. 특히 국가자격시스템 내부관리자와 운영자에 대한 관리체계와 편리성에서 최상의 평가를 도출하였다.