• Journal of Electrical Engineering and Technology
• /
• v.11 no.1
• /
• pp.47-54
• /
• 2016

Microgrids offer several reliability benefits, such as the improvement of load-point reliability and the opportunity for reliability-differentiated services. The primary goal of this work is to investigate the impacts of operating condition on the reliability index for microgrid system. It relies on a component failure rate model which quantifies the relationship between component failure rate and state variables. Some parameters involved are characterized by subjective uncertainty. Thus, fuzzy numbers are introduced to represent such parameters, and an optimization model based on Fuzzy Chance Constrained Programming (FCCP) is established for reliability index calculation. In addition, we present a hybrid algorithm which combines scenario enumeration and fuzzy simulation as a solution tool. The simulations in a microgrid test system show that reliability indices without considering operating condition can often prove to be optimistic. We also investigate two groups of situations, which include the different penetration levels of microsource and different confidence levels. The results support the necessity of considering operating condition for achieving accurate reliability evaluation.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1996.04a
• /
• pp.525-529
• /
• 1996

Decision environments involve a high degree of uncertainty as well as multiple, conflicting goals. Although traditional goal programming offers a means of considering multiple, conflicting goals and arrives at a satisficing solution in a deterministic manner, its major drawback is that decision makers often specify aspiration level of each goal as a single number. To overcome the problem of setting aspiration levels, chance constrained programming can be incorporated into goal programming formulation so that sampling information can be utilized to describe uncertainty distribution. Another drawback of goal programming is that it does not provide a systematic approach to set priorities and trade-offs among conflicting goals. To overcome this weekness, the analytic hierarchy process(AHP) is used in the model. Also, most goal programming models in the literature are of a linear form, although some nonlinear models have been presented. Consideration of risk in technological coefficients and right hand sides, however, leads to nonlinear goal programming models, which require a linear approximation to be solved. In this paper, chance constrained reformulation with linear approximation is presented for a 0-1 goal programming problem whose technological coefficients and right hand sides are stochastic. The model is presented with a numerical example for the purpose of demonstration.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.5
• /
• pp.1709-1718
• /
• 2017

This paper presents a hybrid stochastic deterministic multi-timescale scheduling (SDMS) approach for generation scheduling of a power grid. SDMS considers flexible resource options including conventional generation flexibility in a chance-constrained day-ahead scheduling optimization (DASO). The prime objective of the DASO is the minimization of the daily production cost in power systems with high penetration scenarios of variable generation. Furthermore, energy storage is scheduled in an hourly-ahead deterministic real-time scheduling optimization (RTSO). DASO simulation results are used as the base starting-point values in the hour-ahead online rolling RTSO with a 15-minute time interval. RTSO considers energy storage as another source of grid flexibility, to balance out the deviation between predicted and actual net load demand values. Numerical simulations, on the IEEE RTS test system with high wind penetration levels, indicate the effectiveness of the proposed SDMS framework for managing the grid flexibility to meet the net load demand, in both day-ahead and real-time timescales. Results also highlight the adequacy of the framework to adjust the scheduling, in real-time, to cope with large prediction errors of wind forecasting.

• Applied Biological Chemistry
• /
• v.20 no.3
• /
• pp.285-291
• /
• 1977

In this paper the new statistical method called "New Modified Triangle Test" is studied. This method is to test the null hypothesis based on the result which comes from evaluating sample size "t", where $t{\geqq}3$, by using Triangle Preference Scale Test. It a confirmed that "New Modified Scheffe's Method 1" can be used for appraising "New Modified Triangle Test". In this report, the weight fraction of in-correct oddity chosen to correct oddity chosen is made 1/2 in terms of chance probability.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.9 no.1
• /
• pp.203-219
• /
• 2007

The education chance and job opportunity of women have increased in the 19th century. Also, women tried to get the right and chance equal to men in this period. Therefore, the population of women participating in the sports have increased. And comfortable and practical pantaloons which men have been wearing were suggested to women. This study investigated the characteristics and change of women's sports wear relating to social change in the 19th century. The results of this study were as follows: 1. According to the social change, women participated in the sports activities with the opportunity equal to men, and the appropriate women's sports wear was needed. 2. Pantaloons which were suggested as the clothing reform movement became popular with the development of sports wear. 3. Simple, effective, comfortable and easy style sports wear was preferred. 4. Women accepted men's sports wear positively. 5. The women's sports wear varied according to the various kinds of sports. 6. The healthful design was preferred and harmful design was excluded. 7. Underwear was improved functionally and simplified. 8. The main materials were flannel, wool, tweed, homespun and serge, and the mail colors were brown, dark blue, gray and black.

• Journal of the Korean Home Economics Association
• /
• v.41 no.8
• /
• pp.79-95
• /
• 2003

The main goal of this program is to build a healthy adolescent culture tv broadening the understanding of adolescents and recognition of the environment as well through the development of educational programs centering on the domains of peer relationships, intimacy in dating relationships and sex, leisure activities, and consumption life of adolescents. The program was carried out to 10 young boys and girls for two days/one night and the major findings of the effects of the program through a qualitative evaluation were as follows: First, the program provided adolescent with a proper opportunity to promote a sense of self-confidence through the self-reevaluation process. Secondly, the program provided adolescents with a chance to firmly recognize to become good friends with others though the enhancement of self-esteem, which helped them to build a healthy peer relationship. Thirdly, adolescents were able to promote their views on sex and sexual decision-making by acquiring a proper knowledge of intimacy in dating relationships and of sex, and by candidly expressing their own opinions on sex with instructors. Fourthly, the program provided adolescents with an opportunity to look back on their leisure life with family members which had been neglected thus far and to renew their recognition of active leisure activities. Fifthly, the program provided adolescents with a chance to reflect on their unplanned consumption life and to be firmly determined to refrain from impulsive purchasing and extravagance.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.21 no.4
• /
• pp.264-270
• /
• 2018

Purpose: The aim of this study was to describe functional gastrointestinal disorders (FGID) presented in a tertiary medical center, characteristics of patients and results of the diagnostic work-up together with an outcome during the follow up. Methods: This was a retrospective, single center, observational study including all patients who were diagnosed with FGID based on Rome III criteria from January to December 2015 in tertiary medical center. Results: Overall 294 children were included (mean age, 8.9 years [range, 1-18 years]; 165 females). Majority had functional constipation (35.4%), followed by functional abdominal pain (30.6%), irritable bowel syndrome (17.0%), functional dyspepsia (12.6%), functional nausea (3.4%) and abdominal migraine (1.0%). Regression model found that only significant factor associated with improvement of symptoms is the establishment of the functional diagnosis at the first visit (hazard ratio, 2.163; 95% confidence inverval, 1.029-4.544). There was no association between improvement of symptoms and presence of alarm signs/symptoms (weight loss, nocturnal symptoms and severe vomiting) at diagnosis. Furthermore, in pain symptoms (functional abdominal pain, irritable bowel syndrome, dyspepsia) no treatment positively correlated with pain improvement. Conclusion: Regardless of the initial diagnosis of FGID, positive diagnosis at the first visit increases a chance for resolution of symptoms.

• Journal of Korean Academy of Nursing Administration
• /
• v.12 no.3
• /
• pp.355-364
• /
• 2006

Purpose: This study was conducted to examine the perceptions of nurses and nursing students on nursing law legislation in Korea. Method: This was a descriptive study. The data were collected by questionnaires from 1914 nurses and 408 nursing students and analyzed using descriptive statistics and t-test. Results: Most of respondents (73.5%) had received the information on nursing law legislation mainly through the nursing news letter, nursing magazine(Taehan Kanhoo), and Korean Nurses Association internet homepage. However, they expressed they did not know sufficiently about the nursing law legislation and wanted know more about it. They strongly supported the nursing law legislation. There were significant differences in perceptions between the people who had a chance to know about the nursing law legislation and who did not. Conclusion: Education should be offered not only to the people who wanted to know more about on nursing law legislation and but also to the people who are not concerned or never had a chance to know about this. It is important to empower nurses and nursing students to be proactive on the issues of nursing law legislation.

• Journal of Engineering Education Research
• /
• v.7 no.1
• /
• pp.64-73
• /
• 2004

Universities have to offer efficient education through measuring and evaluating courses precisely. Course evaluation gives instructors a chance of understanding quality and issues arisen in courses, and students a chance of the effective learning. This study investigates general characteristics and administration method of course evaluation in engineering education. The investigation includes elements of course evaluation, various evaluation methods, effective administration methods, and validation of the evaluation. A survey was undertaken to the students at Myongji University regarding course evaluation. The study summarized the results of the survey.

• Journal of Forest and Environmental Science
• /
• v.23 no.2
• /
• pp.79-85
• /
• 2007

This survey was carried out to investigate the utilization situation of fire-wood boiler by the questionnaire and personal interview on rural and mountain households of Gangwon province from 1998 to 2005. The questionnaire include 7 questions on installation, 7 questions on fuel, 3 questions on use, and 3 questions on improvement. Each question was analyzed by percentage to investigate the use situation. This survey indicated that the general problems in use of fire-wood boiler are fuel purchase, collection and transportation, that the development of the household heating boiler using wood-based forming fuel which is cheap, small volume, easy handling, convenient purchase and high heat efficiency could be an alternative to improve the problems and that the continuous expansion of the supply of fire-wood boiler can prevent the devastation of forest through the regulation of imprudent fuel supply. Although the financial aid plan on the installation of fire-wood boiler is in active, many petty households in rural and mountain areas lose a chance to install the fire-wood boiler due to the unsatisfactory information. Thus, it will be desirable for municipal government to prepare the information plan to offer the equal chance and condition to all households in rural and mountain areas and to increase the financial aid for the continuous supply of fire-wood boiler.