• 제어로봇시스템학회:학술대회논문집
• /
• 1988.10b
• /
• pp.764-769
• /
• 1988

In this paper the failure possibility and the error possibility are used to represent reliability of a technical component and that of a human operator, respectively. The failure possibility and the error possibility are fuzzy sets on the interval [0,1]. In a man-machine system, reliability of the technical component and that of the human operator are usually affected by many factors, e.g., the environment in which a machine is operated, psychological stress of the human operator, etc. The possibility is derived from not only the failure or the error rate but also estimates of these factors. The fuzzy reasoning plays an important role in the derivation. The reliability analysis is performed by the use of the possibility obtained by the present method. Moreover this paper discusses the sensitivity analysis which evaluates what extent the change of the estimation of each factor has an influence on reliability of a man-machine system. The important factors to be ameliorated are shown through the sensitivity analysis.

• Nuclear Engineering and Technology
• /
• v.27 no.2
• /
• pp.155-164
• /
• 1995

The steam generator water level control system is studied as a class of randomly sampled nonlinear control systems. The sampling interval and the loop amplification factor are considered as random variables in order to take the operator behavior in account. Stochastic stability using Lyapunov method is used without determining such Lyapunov function. The derived stability criterion is verified with time-domain simulation using the data of CANDU type nuclear power plant, Wolsung 1.

• The Journal of Fisheries Business Administration
• /
• v.52 no.1
• /
• pp.23-46
• /
• 2021

The purpose of this study is to understand the production efficiency of individual fishing communities and provide directions for improvement. The subject of the study is aquaculture type Ochon-Gye in Goheung-gun. The analysis method used bootstrap-DEA to overcome the statistical reliability problem of the traditional DEA analysis technique. In addition, data mining-GIS was applied to identify the spatial productivity of fishing communities. The values of technology efficiency, pure technology efficiency, and scale efficiency were estimated for 32 aquaculture-type fishing villages. Then, using the benchmarking reference set and weights, the projection was presented through adjustment of the input factor excess, and furthermore, the confidence interval of the efficiency values considering statistical significance was estimated using bootstrap.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.46 no.4
• /
• pp.704-722
• /
• 2022

Current studies validate the Body Positive Scale (BP Scale) as a self-assessment instrument that captures four dimensions of the positive body image construct. We developed and evaluated a 17-item BP Scale using two focus group interviews and four independent samples (n = 1,379) of Korean women who completed online survey questionnaires. We generated an initial pool of items via literature review, content validation with experts, and focus group interviews, subsequently refining the items through exploratory analysis (Study 1). We confirmed the BP Scale's underlying dimensions with young Korean female samples (Study 2, Study 4) and with a community sample (Study 3). We also examined the construct validity, internal consistency, and test-retest reliability over a six-week interval. Overall, the results supported that the four-factor BP Scale demonstrates adequate validity and reliability in measuring positive body image among Korean women. The BP Scale provides a method for researchers and practitioners to understand and assess individuals' positive body image in a multifaceted manner.

• Journal of applied mathematics & informatics
• /
• v.41 no.5
• /
• pp.973-988
• /
• 2023

In real-life scenarios, we may have to deal with real numbers or numbers in intervals or a combination of both to solve multi-criteria decision-making (MCDM) problems. Also, we may come across a situation where we must combine this interval and actual number membership values into a single real number. The most significant factor in combining these membership values into a single value is by using aggregation operators or scoring algorithms. To overcome such a situation, we suggest the cubic hypersoft set (CHSS) concept as a workaround. Ultimately, this makes it simple for the decision-maker to obtain information without misconceptions. The primary aim of this study is to establish some operational laws for the cubic hypersoft set, present the fundamental properties of aggregation operators and propose an algorithm by using the technique of order of preference by similarity to the ideal solution (TOPSIS) technique based on correlation coefficients to analyze the stress-coping skills of workers.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.19 no.4
• /
• pp.47-54
• /
• 2005

The improvement of perspectives on dark and limited underground space could be an important factor in successful underground space development. The Current trend in the apartment underground parking garages requires not only quantitatively energy efficient design and operation but also qualitative improvement of the space. For this, we need to consider two factors: Firstly, to understand the characteristics of the lamps; Secondly, to improve the uniformity ratio of illuminance. In a winter season, a way to keep the uniformity and a method not to lower the indoor illuminance level by cold ambient air should be established. Therefore, a change in interval and arrangement of the lighting fixtures is required. Also, in their operations, the current time-fixed control method needs to be changed into the control which method considers the use pattern.

• Korean Journal of Agricultural Science
• /
• v.45 no.2
• /
• pp.283-289
• /
• 2018

Agricultural gear reducers are used in a variety of agricultural machinery designs such as in agricultural tractors and transport cars, and even greenhouses. For greenhouses, a gear reducer is used to control windows on the side and the roof. Gear reducers for agricultural applications are designed using the empirical method because of the lack of a standard for experimentation. Simulation is necessary for the optimal design of an agricultural gear reducer. There are many advantages to this optimization such as low-cost maintenance, reduced size, and weight. In this study, bending and contact safety factor simulation for the gear reducer of a greenhouse was conducted by decreasing the face widths of helical gear shaft 2 and shaft 3 from 30.8 and 30 mm, respectively, at an interval of 4 mm. The bending and contact safety factors were calculated using AGMA standard. Simulation results showed that bending and contact safety factors decreased rapidly when the face width of the helical gear on shaft 2 was 30 mm and the face width of helical gear on shaft 3 decreased from 30.8 mm to 26.8 mm, suggesting that it would be safe to reduce the face width of the helical gear on shaft 3 to 26.8 mm. The reduction of the face width also reduced the weight of the agricultural gear. This study suggests that the agricultural gear reducer safety factor decreases as the face width decreases.

• Journal of Wetlands Research
• /
• v.18 no.2
• /
• pp.148-153
• /
• 2016

Hydraulic and hydrological flood routing methods are commonly used to analyze temporal and spatial flood influences of flood wave through a river reach. Hydrological flood routing method has relatively more simple and reasonable performance accuracy compared to the hydraulic method. Storage constant used in Muskingum method widely applied in hydrological flood routing is very similar to the travel time. Focusing on this point, in this study, we estimate the travel time from HEC-RAS results to estimate storage constant, and develop a non-linear regression equation for the travel time using reach length, channel slope, and discharge. The estimated flow by Muskingum model with storage constant of nonlinear equation is compared with the flow calculated by applying the HEC-RAS 1-D unsteady flow simulation. In addition, this study examines the effect on the weighting factor changes and interval reach divisions; peak discharge increases with the bigger weighting factor, and RMSE decreases with the fragmented division.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.3 no.3
• /
• pp.95-106
• /
• 1983

The probability of failure is used to analyze the reliability of three dimensional slope failure, instead of conventional factor of safety. The strength parameters are assumed to be normal variated and beta variated. These are interval estimated under the specified confidence level and maximum likelihood estimation. The pseudonormal and beta random variables are generated using the uniform probability transformation method according to central limit theorem and rejection method. By means of a Monte-Carlo Simulation, the probability of failure is defined as; $$P_f$$=M/N N: Total number of trials M: Total number of failures some of the conclusions derived from the case study include; 1. If the strength parameters are assumed to be normal variated, the relationship between safety factor and the probability of failure is fairly consistent, regardless of the procedures of analysis and dimensions of assumed rupture surfaces. 2. However if the strength parameters are beta variated, general relationship between $F_s$ and $P_f$ is hardly found.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.18 no.2
• /
• pp.376-380
• /
• 2004

The purpose of this study is the develop a questionnaire for measuring Yin-Deficiency and examine the reliability and validity for its' value as a barometer for evaluating Yin-Deficiency. Questionnaire was developed according to the symptoms of Yin-Deficiency suggested in the 'Standardization of diagnostic terms and requirements of Korean Medicine', With and as a reference, each symptom has been worked on to be put on the questionnaire. Visual analogue scales(VAS) was used as a barometer for measuring frequency of manifestation of symptoms. A study was performed to measure validity and reliability of the final questionnaire for analysis. reliability of YinDQ was measured by Cronbach's alpha coefficient and test-retest method. This study utilized factor analysis and clinical validity for evaluation of validity. For the purpose of decreasing the amount of data-the number of factors, and at the same time minimize the loss of information factor analysis was performed Component factors were extracted using Principal Component Analysis. This study evaluated the clinical validity for examination of difference between the normal group and the patient group. Evaluation on the's internal consistency showed strong internal consistency with value of 0.8615. reliability from test-rest with three-week interval, followed by comparisons of the correlation coefficient and mean values of each item between the two. The Spearman correlation coefficient was 0.54-0.79. By factor analyse two factors with Eigen value of greater than 2.2 were selected. Factor 1 consists of items of 'irritable fever on the five Hearts', 'flushing of the zygomatic region in the afternoon', 'tidal fever', 'night sweats', and 'dryness on the mouth or the throat'. Factor two consists of items of 'emaciation', 'dizziness', 'insomnia', 'decreased amount of urine with yellowish color', and 'constipation'. The comparison between the patient group and the normal group showed significant differences for every ten questions. The results implies that YinDQ is a barometer with sufficient reliability and validity. The questionnaire for Yin-Deficiency may not be enough to replace the specific differential diagnosis by a doctor of Oriental medicine. Nevertheless, it can be effectively utilized as an assisting method in consultation or a method of measuring the degree of Yin-Deficiency in a group.