• Journal of Electrical Engineering and Technology
• /
• 제3권1호
• /
• pp.52-59
• /
• 2008

This paper describes the secant method for solving the economic dispatch (ED) problem with generator constraints and transmission losses. The ED problem is an important optimization problem in the economic operation of a power system. The proposed algorithm involves selection of minimum and maximum incremental costs (lambda values) and then the evaluation of optimal lambda at required power demand is done by secant method. The proposed algorithm has been tested on a power system having 6, 15, and 40 generating units. Studies have been made on the proposed method to solve the ED problem by taking 120 and 200 units with generator constraints. Simulation results of the proposed approach were compared in terms of solution quality, convergence characteristics, and computation efficiency with conventional methods such as lambda iterative method, heuristic methods such as genetic algorithm, and meta-heuristic methods like particle swarm optimization. It is observed from different case studies that the proposed method provides qualitative solutions with less computational time compared to various methods available in the literature.

• 한국항행학회논문지
• /
• 제13권5호
• /
• pp.781-786
• /
• 2009

클라우드 컴퓨팅 환경은 웹을 기반으로 한 응용분야의 새로운 트랜드이다. 이는 많은 사용자들이 쉽게 인터넷을 통해 자원을 할당받고 서비스를 지원받을 수 있는 IT 비즈니스 모델이라 할 수 있다. 또한 u-러닝은 인터넷 기반 학습의 효율성을 극대화한 모델이다. 따라서 본 연구는 이를 인터넷 기반 학습에 응용하는 u-러닝 교수 학습 모형의 설계를 제시하고자 한다. 제안된 교수 학습 모형은 u-러닝에 맞도록 준비, 계획, 수집, 학습 진행, 분석 및 평가, 피드백의 7단계로 구성하였다. 이는 클라우드 u-러닝 서버와 클라우드 LMS를 두어 처리 및 관리하도록 하였으며, 학습자의 이동형 기기 모델의 인식을 위하여 이동형 기기 메타데이터를 두도록 하였다.

• Structural Engineering and Mechanics
• /
• 제61권2호
• /
• pp.283-293
• /
• 2017

The main contribution of the present paper is to propose an intelligent fuzzy inference system approach for modeling the debonding strength of masonry elements retrofitted with Fiber Reinforced Polymer (FRP). To achieve this, the hybrid of meta-heuristic optimization methods and adaptive-network-based fuzzy inference system (ANFIS) is implemented. In this study, particle swarm optimization with passive congregation (PSOPC) and real coded genetic algorithm (RCGA) are used to determine the best parameters of ANFIS from which better bond strength models in terms of modeling accuracy can be generated. To evaluate the accuracy of the proposed PSOPC-ANFIS and RCGA-ANFIS approaches, the numerical results are compared based on a database from laboratory testing results of 109 sub-assemblages. The statistical evaluation results demonstrate that PSOPC-ANFIS in comparison with ANFIS-RCGA considerably enhances the accuracy of the ANFIS approach. Furthermore, the comparison between the proposed approaches and other soft computing methods indicate that the approaches can effectively predict the debonding strength and that their modeling results outperform those based on the other methods.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2002년도 학술대회지
• /
• pp.659-662
• /
• 2002

The present paper presents the experimental results for pressure drop in inclined tube bundles located in a rectangular duct. Measurements are made for pressure drop in triangular and rotated triangular tube arrays having P/d ratio of 1.6 and inclination angles of 30,45,60 and 90 degrees. The Reynolds number based on the free stream velocity and tube diameter ranges from $8{\times}10^2\;to\;6.3{\times}10^{4}$. The experimental results show that the magnitude of dimensionless pressure drop decreases significantly when the inclined angle is less than 45 degree. The measured data are compared with two existing correlations available in the literatures. The ESDU correlation agrees well with the present data far the triangular arrays. But some discrepancies are observed for the rotated triangular arrays when the inclined angles are 30 and 45 degrees. The Idel'chik correlation generally agrees well with the measured data for the rotated triangular arrays except for the inclined angle of 30 degree. The Idel'chik correlation needs modification for the triangular arrays. The modified Idel'chik correlation agrees well with the measured data within $10{\%}$. It is found that the present measured data can be applied to the evaluation and modification of previous correlations.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
• /
• 제6권2호
• /
• pp.113-119
• /
• 2000

본 논문에서는 주기억장치 데이타베이스의 특성을 반영하여 시간제약조건을 처리할 수 있는 실시간 주기억장치 데이타베이스시스템을 위한 질의 처리기를 설계하고 구현한다. 제안된 질의 처리기는 메타 데이타베이스를 이용하여 시간제약을 갖는 실시간 데이타를 유지 관리한다. 응용 프로그램의 작성을 위해서 CLI를 지원하고 있으며, 이를 확장한 확장 CLI와 저장 CLI를 지원하여 확장 CLI를 이용하여 실시간 트랜잭션의 정보를 CLI를 사용으로 표현할 수 있도록 하였고, 빈번하게 수행되는 트랜잭션을 지원하기 위해 저장 CLI를 지원한다. 제안된 질의 처리기는 주기억장치 실시간 데이타베이스 관리시스템의 질의처리기로 구현하였으며, 성능평가를 통해서 시스템의 질의처리 능력과 실시간 데이타의 효율적인 관리를 통해서 종료시한을 만족하는 실시간 트랜잭션의 비율이 증가됨을 보였다.

• 대한한의학회지
• /
• 제31권1호
• /
• pp.69-80
• /
• 2010

Objectives: This study aimed to find determinants of customers' use of and satisfaction with oriental medical services in Korea. Methods: A total of 33 articles which consist of 9 articles published in academic journals, 20 master's theses, and 4 doctoral dissertations were included in the systematic review. Among the articles used in the study, 29 used primary survey data, while 4 used secondary data produced by the Korean National Health and Nutrition Evaluation Survey. Results: First, it was found that people who prefer to use oriental medical services usually have one or more of the following diseases: musculoskeletal disorders, paralysis, or diseases or injuries without clear diagnosis. Other variables of gender, age, expectation of treatment outcome, and kindness of doctor and other staff were found to be significant determinants of using the oriental medical services. Second, the determinants of customers' satisfaction with oriental medical services were found to be age, gender, level of education, chronic disease with long length of stay, kindness of staff, medical cost, clinical environment, doctor's reputation, and public image of the institutions. Conclusion: The results of this study can be used to develop marketing strategies for oriental medical institutions in Korea.

• 한국염색가공학회지
• /
• 제30권1호
• /
• pp.20-28
• /
• 2018

The near infrared ray camouflage fabric has a near infrared ray reluctance similar to the surrounding environment and has a camouflage effect on the surrounding environment. Synthetic fibers used in military uniforms are difficult to have gastrointestinal function as general commercial dyes, unlike cellulose fibers, which use some commercial vat dyes to impart infrared gastrointestinal function. In this study, we optimized the adsorption pH, temperature and time for NIR dye application for polyester fabrics, and established the optimum concentration for the evaluation of adsorption build-up characteristics. In addition, it is difficult to adsorb it since the polyester material has a dense crystal structure and the NIR dye is bulky. Therefore, a swelling agent used for dyeing meta-aramid fibers with high Tg and high crystallinity was introduced as a separate preparation to increase the affinity to polyester, which is a hydrophobic fiber, to thereby obtain an excellent adsorption rate. As a result of comparing before and after using swelling agent, the adsorption rate difference was 10 times or more when compared with before.

• 한국과학교육학회지
• /
• 제12권2호
• /
• pp.97-107
• /
• 1992

ln this study, we analyzed 5 science textbooks currently used for the 7th graders quantitatively by using the science textbook rating system of Collette and Chiappetta(1986), making meta-analysis of the results of 17 graduate school students of Seoul National University. The rating system consists of 11 categories with detailed items respectively : content, organization, reading level, instruction approach, illustrations, end-chapter teaching aids, laboratory activities in text and/or accompanying manual, teacher aids, indices and glossaries and mechanical makeup of text. Each item in the checklist is to be given between one and five points and the total number of possible points in this rating system is 290. It was shown that 5 science textbooks currently used for 7th-year-students were all "poor" in terms of total points and had, at large, uniformed results especially in 10 items; 7 items concerning moral and ethical implications of science, vocabulary lists, accompanying laboratory manual, annotated editions for test, supply list for laboratory program, student workbook and glossary with low points, while 3 items concerning facilities needed for laboratory activities, activities relevant to the content and textbook size with high points. A Science teachers could get a broad view with a correct impression of the books usefulness in making an evaluation of available textbooks.

• Journal of information and communication convergence engineering
• /
• 제9권4호
• /
• pp.379-384
• /
• 2011

The scope of the problems that could be solved by monitoring and the improvement of the recognition time is directly correlated to the performance of the management function of the business process. However, the current monitoring process of business activities decides whether to apply warnings or not by assuming a fixed environment and showing expressions based on the design rules. Also, warnings are applied by carrying out the measuring process when the event attribute values are inserted at every point. Therefore, there is a limit for distinguishing the range of occurrence and the level of severity in regard to the new external problems occurring in a complicated environment. Such problems cannot be ed. Also, since it is difficult to expand the range of problems which can be possibly evaluated, it is impossible to evaluate any unexpected situation which could occur in the execution period. In this paper, a process-evaluating model based on the goal scenario is suggested to provide constant services through the current monitoring process in regard to the service demands of the new scenario which occurs outside. The new demands based on the outside situation are analyzed according to the goal scenario for the process activities. Also, by using the meta-heuristic algorithm, a similar process model is found and identified by combining similarity and interrelationship. The process can be stopped in advance or adjusted to the wanted direction.

• 정보화정책
• /
• 제20권1호
• /
• pp.3-21
• /
• 2013

본 연구는 사이버윤리와 관련된 2002년부터 2012년까지의 국내 연구들을 메타 분석하였다. 가장 연구가 활발한 연구 분야는 교육학분야로 나타났고, 그 외의 분야로는 법학, 신문방송학, 철학, 사회복지학, 사회학, 행정학, 경영학, 심리학 순이었다. 사이버 윤리는 각 전공분야별로 중점적인 연구 영역이 다르게 나타났다. 사이버연구 분석결과 사이버 공간의 특수성을 반영한 윤리이론 개발이 미흡하고, 대부분의 연구들이 기존의 윤리 철학적 범주를 벗어나지 못하는 경향을 보이는 것이 문제점으로 지적된다. 사이버윤리에 대한 연구의 경향이 추상적인 도덕규범 정립에 그치는 것도 문제점으로 볼 수 있다. 또한 새롭게 등장하는 정보인권에 대한 인식 또한 부족하여 실천적 생활윤리에 관한 연구가 미흡하였다. 향후 연구에 있어서 사이버 공간의 정보인권적 윤리의식이 제고되어야 하고, 학제간의 융합적인 연구의 필요성도 요청된다.