• 자원ㆍ환경경제연구
• /
• 제25권2호
• /
• pp.229-253
• /
• 2016

기후변화 대응 및 에너지 안보를 위해 세계 각국에서는 다양한 재생에너지 보급 정책을 수립, 시행하고 있다. 재생에너지 정책이 재생에너지 확산에 미치는 영향을 분석하는 많은 선행연구들에서는 종속변수로 재생에너지 발전량을 사용하고 있는데 자기상관(autocorrelation) 문제의 발생 가능성에도 불구하고 정태적 모형을 쓰고 있다는 점, 기술채택에 선행되어야 하는 기술혁신의 영향을 고려하지 않았다는 점에서 한계점을 지닌다. 본 연구에서는 동적 패널 모형(dynamic panel model)을 이용하고 기술혁신 변수를 추가함으로써 위의 두 한계점을 극복하고자 하였다. 분석 결과 FIT가 RPS보다 재생에너지 보급에 보다 효과적임을 알 수 있고, 재생에너지 기술혁신 또한 재생에너지 확대에 긍정적으로 기여한다는 사실을 밝혀내었다. 또한 이 결과를 바탕으로 기존 선행연구에서 공통적으로 직관과 어긋난 결과를 도출한 데에는 위의 두 한계점이 원인일 수 있다는 가능성을 확인하였다.

• 한국도서관정보학회지
• /
• 제44권2호
• /
• pp.197-215
• /
• 2013

본 연구는 우리나라 대학도서관의 차세대 OPAC 기능 채택 현황을 조사 분석한 것으로 새로운 OPAC 시스템을 도입하거나 시스템개편을 계획하고 있는 도서관에 유용하게 쓰일 것이다. 본 연구에서는 선행연구들을 검토하여 차세대 OPAC 기능의 예비항목들을 추출하고 이것을 검증하기 위해 파일럿 테스트를 실시하였다. 본연구에서의 조사대상은 우리나라 191개 대학도서관 전수로 하였으며 데이터의 정확성을 기하기 위해 두 명의 연구원이 중복 조사하였다. 수집된 데이터는 PASW Statistics 18을 사용하여 분석하였다. 가장 많이 채택된 차세대 OPAC 기능은 간단검색창이었고, 그 다음은 결과내검색이었다. 클러스터링, 오픈서치플러그인, 적합성순정렬, 철자오류 수정은 소수의 도서관만이 사용하고 있는 것으로 나타났다.

• 비파괴검사학회지
• /
• 제29권1호
• /
• pp.10-14
• /
• 2009

초음파 적외선 비파괴 열화상 검사기술의 발열 메커니즘은 정확히 규명되지 않았으나, 열-기계 연성효과와 결함 계면 사이의 마찰효과가 주요한 원인인 것으로 추정되고 있다. 본 논문에서는 피로균열을 갖는 알루미늄 합금 시험편에서 결함을 검출하고, 실험조건으로부터 각각의 메커니즘에 따라 온도 변화를 수치 예측하였다. 시험결과와 수치예측 결과로부터 발열의 주요한 원인이 마찰이라는 것을 밝혔다.

• International Journal of CAD/CAM
• /
• 제6권1호
• /
• pp.199-211
• /
• 2006

Practical automated flat pattern generation with inbuilt production features for doubly curved sheet metal components (SMCs) is addressed here utilizing a new and unique Point Transformation Algorithm (PTA). This is the third in the series of papers on practical Flat Pattern Development (FPD) [8] and Production Loft Generation Systems (PLGS) [9] complementing the pioneering work [6,7]. In the first two publications, automated loft generation programs have addressed sheet metal components having a Principal Flat Surface (PFS) only. The flat pattern development of 3-D components that do not have the flat surface(termed as Non-PFS components) having complex features of double curvature in addition to cutouts and nibbled holes typical of aircraft components were so far not addressed due to lack of relevant published algorithms. This paper traces the evolution of developments and provides the record of fully illustrated, automated loft generation scheme for aircraft SMCs including the Non-PFS components which underwent validation through production tests by sponsors. Details of some of the unique features of the system like simplified surface model generation, termed as topological model and powerful algorithms deployed with potential for CAD/CAM applications are included.

• 복식
• /
• 제53권3호
• /
• pp.31-49
• /
• 2003

The Purpose of this research is to examine and contrast the cultural characteristics of the street fashion in new generations of Korea and Japan. We also intended to help clothing companies understand the current trend in this new generation. As the method for street fashion analysis. various literature, internet information and new media materials were utilized. Key observations obtained are as following First, they pursue a complex image. New generations seem to admix images from different areas to create a synthetic image, rather than adopting a single image; Second, practicality is an important factor. They Pursue a sense of their own unique trend: Third, distinction. The difference in society values between Koreans and Japanese is incorporated. The Korean new generation considers the traditional moral principles as important social values. In contrast the Japanese new generation is greatly influenced by the open sexuality culture ; Fourth. public ownership and sharing of the culture. There is a gradual deviation from a dominating unidirectional influence from one country on another. Now the two countries are influencing each other ; Fifth, sense. There are numerous fashion items and generalized total coordination. New generations express more active and creative fashion sense in those fashion items.

• Agricultural and Biosystems Engineering
• /
• 제6권1호
• /
• pp.22-26
• /
• 2005

A wind-heat generation system was developed and the system consisted of an electric motor, a heat generation drum, a heat exchanger, two circulation pumps and a water storage tank. The heat generation drum is an essential element determining performance of the system. Frictional heat was generated by rotation of a rotor in the drum filled with a working fluid, and the heat stored in the fluid was used to increase water temperature through the heat exchanger. Effects of some factors such as rotor shape, kind and amount of working fluid, rotor rpm and water flow rate in the heat exchanger, affecting the system performance were investigated. Amounts of heat generated were varied, ranging from 126,000 to 32,760 kJ/hr, depending on combination of the factors. Statistical analysis using GLM procedure revealed that the most influential factor to decide the system performance was amount of the fluid in the drum. Experiments showed that the faster the speed of the rotor, the greater heat was obtained. The greatest efficiency of the heat generation system, electric power consumption rate vs gained heat amount of water, was about 70%. Though the heat amount was not enough for plant bed heating of a 0.1-ha greenhouse, the system would be promising if some supplementary heat source such as air- water heat pump is added.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제10권7호
• /
• pp.3414-3434
• /
• 2016

Classical key generation is complicated to update and key distribution generally requires fixed infrastructures. In order to eliminate these restrictions researchers have focused much attention on physical-layer (PHY-layer) based key generation methods. In this paper, we present a PHY-layer fingerprints based fuzzy key generation scheme, which works to prevent primary user emulation (PUE) attacks and spectrum sensing data falsification (SSDF) attacks, with multi-node collaborative defense strategies. We also propose two algorithms, the EA algorithm and the TA algorithm, to defend against eavesdropping attacks and tampering attacks in mobile cognitive radio networks (CRNs). We give security analyses of these algorithms in both the spatial and temporal domains, and prove the upper bound of the entropy loss in theory. We present a simulation result based on a MIMO-OFDM communication system which shows that the channel response characteristics received by legitimates tend to be consistent and phase characteristics are much more robust for key generation in mobile CRNs. In addition, NIST statistical tests show that the generated key in our proposed approach is secure and reliable.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 A
• /
• pp.550-552
• /
• 2001

The vertically integrated power industry was divided into six generation companies and one market operator, where electricity trading was launched at power exchange. In this environment, the profits of each generation companies are guaranteed according to utilization of their own generation equipments. Especially, the electricity demand shows seasonal and weekly regular pattern, which the some capacity should be provided into ancillary service based on the past demand forecasting error and operating results of electricity market. Namely, if generation cost function is applied to SMP and BLMP as announced the previous day, the available generation capacity of the following day could be optimally distributed, and therefore contract capacity of ancillary service applied to CBP(Cost Based Pool) and TWBP(Two-Way Bidding Pool) is determined. Consequently, it is Possible to use the retained equipments optimally. This paper represents on efficient bidding strategies for generation equipments through the calculation of the contract and the application of each generator cost function based on the past demand forecasting error and market operating data.

• 한국CDE학회논문집
• /
• 제12권3호
• /
• pp.153-162
• /
• 2007

In this paper, we propose a knowledge-based method for generating CNC torch path for laser cutting of the outlines of planar shapes. The proposed method consists of two main phases: laser cutting knowledge construction and CNC torch path generation using the knowledge. In the first phase, cutting experiments are conducted on various operating parameters, and then empirical data are stored and analyzed to make up the knowledge of laser cutting. With this knowledge, we can inquire what a kerf width is for specific operating parameters. In the second phase, using the knowledge of laser cutting, CNC torch path is generated for cutting the outlines of the given planar shapes. This phase is basically based on the offset generation of each outline by a sequence of arc splines, where the offset distance is the same as the half of the kerf width determined from the constructed knowledge. The proposed method based on laser cutting knowledge makes full use of arc interpolators in CNC torch path generation. The method can efficiently reduce the number of path segments while keeping the torch path within the desired accuracy.

• 한국컴퓨터정보학회논문지
• /
• 제11권1호
• /
• pp.11-18
• /
• 2006

LAD(Logical Analysis of Data)는 Boolean-logic에 기반을 둔 데이터 마이닝 방법론이다. LAD에 의한 데이터 분석 시 중요한 과정은 데이터 집합에 숨겨진 구조적 정보를 패턴의 형식으로 발견해내는 패턴 생성 단계이다. 기존의 패턴 생성 방법은 열거법에 기반을 두고 있어 높은 차수의 패턴을 생성하는 것은 실질적으로 불가능하였다. 본 논문에서는 최적화에 기반을 둔 패턴 생성 방법론을 제안하고 혼합 정수 선형 모형과 SCP(Set Covering Problem)의 두 가지 모형을 제안한다. 기계학습 분야에서 널리 쓰이는 데이터 집합에 대해 제안된 패턴 생성 방법을 이용한 분석 실험을 통하여 기존의 패턴 생성 방법으로는 생성될 수 없는 패턴을 쉽게 생성하는 효율성을 입증하였다.