• Title/Summary/Keyword: reliability factors

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Evaluation for Lifetime and Thermal Ratings for Aged Overhead Transmission Lines (노후 가공송전선의 수명과 열용량의 평가)

  • Kim, Sung-Duck
    • Journal of IKEEE
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    • v.16 no.1
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    • pp.1-6
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    • 2012
  • Thermal rating or lifetime evaluation for aged overhead transmission line becomes more important concerns with respect to keeping power delivery stable having proper capability. Both load rating and dip/clearance are essential factors to determine transmission capacity. In order to evaluate thermal rating and conductor lifetime for domestic transmission lines with double-circuit, the dip/ground clearance standards as well as the electrical equipment technical standard are examined. Conductor temperature and dip are calculated under the assumption of a contingency, and then, a method to up-rate load capacity is searched. As thermal rating and limit dip for aged conductor are properly evaluated, an improved strategy in order to guarantee the existing power system reliability is presented in this paper.

Analysis of Influence Factors on the Intention to Use Personal Cloud Computing (개인용 클라우드 컴퓨팅 사용에 미치는 영향요인 분석)

  • Ryu, Jae Hong;Moon, Hye Young;Choi, Jinho
    • Journal of Information Technology Services
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    • v.12 no.4
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    • pp.319-335
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    • 2013
  • Cloud computing allows users to access software or specific programs that support the cloud platform through an information communicating device that can connect to the internet anywhere or anytime. Also, the cloud architecture not only reduces the expenses of IT infrastructure construction and maintenance, but also speeds up processing and mobility, which leads to a significant ease of use. In spite of the advantages of cloud computing, previous studies have been centered on case studies of the execution, advantages, and problems of cloud computing. In contrast, empirical research on individual cloud computing up till now is very insufficient. Thus, the research aims to create a model of an individual user's perspective and verify validation. This study reveals types of influence that characteristics can have on an individual user's intention to use, by searching the characteristics that the individual user recognizes on cloud computing services. The results are as follows:first, the characteristics of cloud computing indicates a significant influence on usage intention. Second, all characteristics in cloud computing, accessibility, reliability, perceived ease of use, and fusibility, are confirmed in providing significant influences in shaping social influence forms. Third, social influence has a significant influence on usage intention.

Development of Accelerated Failure-free Test Method for Automotive Alternator Magnet (자동차 교류발전기용 자석에 대한 가속 무고장시험방법 개발)

  • Liu, Qiang;Ismail, Azianti;Jung, Won
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.36 no.4
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    • pp.92-99
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    • 2013
  • Many automotive components for power generation such as motors and alternators have been widely using ferrite magnets. To ensure a high level of efficiency could be achieved in an alternator, the assembled magnets must be in good enough durability. Recently, some hairline cracks have been found on the magnet produced by manufacturers in Korea. Thus, there is an increasing concern that some of the magnets produced could cause further problems after being assembled in the alternator. Based on the standard alternator test (RS0008 : 2006), this paper has developed an accelerated failure-free test for magnets in alternator to demonstrate that assembled magnets will meet durability objective specified by the manufacturer. This guarantees the target life of the magnet with 90 percent reliability and 90 percent confidence level (R90C90). Temperature and rotation speed were selected as accelerated stress factors.

Dimensions and Assessment of Korean Parenting Style (한국 부모의 자녀 양육방식에서의 차원과 평가)

  • 조복희;이진숙;이흥숙;권희경
    • Journal of the Korean Home Economics Association
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    • v.37 no.10
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    • pp.123-133
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    • 1999
  • The purpose of the study was to develop the parenting style scale which is reflecting cultural background of Korean parent's parenting for their children. The instalment was designed based on the literature reviews and on the Baumrind's parenting style. A total of three hundred and sixty two mothers whose children from first and second grade in elementary school completed the Questionnaires. The questionnaires consisted with the items addressing different types of parenting style which include love and care, encouragement of independence, enjoyment in parenting, communication, control, control of aggressiveness, strategies of control , request of maturity. Factor of analysis was applied to examine validity of Korean parenting style scale. Based on the factor analysis, 33 items selected for final questionnaire and two factors discovered. The first factor which named 'warmth'included 20 items such as love and care toward their children, communication, enjoyment in parenting, encouragement toward independency. The second factor which named'control'included 13 items such as control of children's behavior and discipline of children. Warmth factor accounted for 46% of variance and control factor accounted for 18% of variance. Internal consistency was also checked. Although warmth and control factor represented a moderate internal consistency, control factor showed lower correlations then warmth factor. The reliability estimates (Cronbach alpha) were. 87 and 71 for warmth and control factor respectively. Korean parenting style scale can be used to address the appropriateness of Baumrind's theoretical assumptions in parenting style as well as to examine parenting style for Korean population. However, this instalment was developed with Korean mothers only. Further analysis need to be addressed with fathers.

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A comprehensive approach to flow-based seismic risk analysis of water transmission network

  • Yoon, Sungsik;Lee, Young-Joo;Jung, Hyung-Jo
    • Structural Engineering and Mechanics
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    • v.73 no.3
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    • pp.339-351
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    • 2020
  • Earthquakes are natural disasters that cause serious social disruptions and economic losses. In particular, they have a significant impact on critical lifeline infrastructure such as urban water transmission networks. Therefore, it is important to predict network performance and provide an alternative that minimizes the damage by considering the factors affecting lifeline structures. This paper proposes a probabilistic reliability approach for post-hazard flow analysis of a water transmission network according to earthquake magnitude, pipeline deterioration, and interdependency between pumping plants and 154 kV substations. The model is composed of the following three phases: (1) generation of input ground motion considering spatial correlation, (2) updating the revised nodal demands, and (3) calculation of available nodal demands. Accordingly, a computer code was developed to perform the hydraulic analysis and numerical modelling of water facilities. For numerical simulation, an actual water transmission network was considered and the epicenter was determined from historical earthquake data. To evaluate the network performance, flow-based performance indicators such as system serviceability, nodal serviceability, and mean normal status rate were introduced. The results from the proposed approach quantitatively show that the water network is significantly affected by not only the magnitude of the earthquake but the interdependency and pipeline deterioration.

Probabilistic capacity spectrum method considering soil-structure interaction effects (지반-구조물 상호작용 효과를 고려한 확률론적 역량스펙트럼법)

  • Nocete, Chari Fe M.;Kim, Doo-Kie;Kim, Dong-Hyawn;Cho, Sung-Gook
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2008.04a
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    • pp.65-70
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    • 2008
  • The capacity spectrum method (CSM) is a deterministic seismic analysis approach wherein the expected seismic response of a structure is established as the intersection of the demand and capacity curves. Recently, there are a few studies about a probabilistic CSM where uncertainties in design factors such as material properties, loads, and ground motion are being considered. However, researches show that soil-structure interaction also affects the seismic responses of structures. Thus, their uncertainties should also be taken into account. Therefore, this paper presents a probabilistic approach of using the CSM for seismic analysis considering uncertainties in soil properties. For application, a reinforced concrete bridge column structure is employed as a test model. Considering the randomness of the various design parameters, the structure's probability of failure is obtained. Monte Carlo importance sampling is used as the tool to assess the structure's reliability when subjected to earthquakes. In this study, probabilistic CSM with and without consideration of soil uncertainties are compared and analyzed. Results show that the analysis considering soil structure interaction yields to a greater probability of failure, and thus can lead to a more conservative structural design.

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Uncertainty evaluation in electrochemical noise resistance measurement (전기화학적 노이즈 저항 측정에서의 불확도 평가)

  • Kim, Jong Jip;Kang, Su Yeon
    • Corrosion Science and Technology
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    • v.12 no.5
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    • pp.220-226
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    • 2013
  • The uncertainty in statistical noise resistance measurement was evaluated for a type 316 stainless steel in NaCl solutions at room temperature. Sensitivity coefficients were determined for measurands or variables such as NaCl concentration, pH, solution temperature, surface roughness, inert gas flow rate and bias potential amplitude. The coefficients were larger for the variables such as NaCl concentration, pH, inert gas flow rate and solution temperature, and they were the major factors increasing the combined standard uncertainty of noise resistance. However, the contribution to the uncertainty in noise resistance measurement from the above variables was remarkably low compared to that from repeated measurements of noise resistance, and thus, it is difficult to lower the uncertainty in noise resistance measurement significantly by lowering the uncertainties related with NaCl concentration, pH, inert gas flow rate and solution temperature. In addition, the uncertainty in noise resistance measurement was high amounting to 17.3 % of the mean, indicating that the reliability in measurement of noise resistance is low.

Visual Evaluation of Retro-Romantic Fashion (레트로 로맨틱 패션의 시각적 평가)

  • Cho, Mal-Hee;Lee, Myoung-Hee
    • The Research Journal of the Costume Culture
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    • v.17 no.3
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    • pp.523-534
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    • 2009
  • The purpose of this study is to categorize the dimensions of the visual evaluation of the costume details of the retro romantic fashion and to research on the costume details and the visual evaluation by evaluators' gender, age, and major, and on their preferences. Quantitative research were conducted for this study. Based on the pictures, 10 costume details were selected for the survey questions and data were collected. All 446 subjects who participated in this research were college students(males and females) residing in or near Seoul. Data were collected in September, 2008. The collected data were statistically analyzed using SPSS which included: factor analysis, Cronbach's $\alpha$ reliability analysis, three-way ANOVA, two-way ANOVA, one-way ANOVA, Duncan's multiple range tests, and the t-test. The results of visual evaluation of retro romantic fashion are as follows: First, as a result of the factor analysis of the costume detail evaluation, five factors including attractiveness, decorativeness, cuteness, retro, and femininity surfaced. Second, the gender difference in the results of the research revealed that women rated decorative, cute, retro, and feminine characteristics higher than men did. Third, there were significant interactive effects in attractiveness and femininity depending on costume details and evaluators' gender. Fourth, subjects majoring in fashion valued attractiveness and femininity of the stimulus over non-fashion majoring subjects. Fifth, there were significant differences in the preferences of costume details depending on gender.

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A Study on the Impact of Employee's Awareness about Corporate Social Responsibility on Innovative Behavior ; Targeting Frontline Employees in the Hotel Industry

  • Choi, Hyun-Jung
    • Culinary science and hospitality research
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    • v.22 no.1
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    • pp.78-86
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    • 2016
  • This study is designed to investigate the impact of employee's awareness about corporate social responsibility on innovative behavior among frontline employees in the hotel industry. In addition, the present study seeks to demonstrate whether employees awareness about corporate social responsibility or innovative behavior varies according to gender, age, education level and employment type. In order to achieve the study goal, the data were obtained from frontline employees(Rooms division, F&B division) working in the 5-star hotels. And the data were analyzed by frequency analysis, factor analysis, reliability analysis, t-test, ANOVA and regression analysis were undertaken using SPSS(18.0). The results showed that gender, age and employment type were not significant factors to generate differences on awareness about corporate social responsibility. But the higher educated employee was likely to perceive the awareness about corporate social responsibility better. Employee's innovative behavior varied on all of gender, age, education level and employment type. In other words, employee who is male, in the older age group, in the higher educated level and the full-time position tends to do more innovative behavior. Implications based on the study results are also discussed.

Determinants of Talent Retention in Textile and Garment Companies in Binh Duong Province

  • NGUYEN, Thanh-Lam
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.6
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    • pp.475-484
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    • 2020
  • This study investigates determinants of talent retention in textile and garment companies located in Vietnam's Binh Duong province to propose feasible actions for their sustainable development in the current context of competition on the labor market. This study uses self-completed questionnaires to collect data which are then analysed with statistical methods including scale reliability, exploratory factor analysis, and multiple linear regression. Specifically, results from an official survey of 129 people who are regarded as talents in related companies show that there are ten determinants, ranked in descending order of their importance, including: working environment; training and promotion opportunities; salary and benefits; personal loyalty; relationship with colleagues; nature of work; organizational recognition; type of ownership; relationship with superiors; and working experience. Moreover, it is also found that foreign companies are better in retaining their talents than private domestic ones. These findings suggest that, depending on their available resources, organizations need to focus on some of these factors to improve their talent retention; among them, it is critical to provide creative space or create conductive working environment by providing talents with proper tools and equipment for them to feel excited with their work and get things done in an optimal, efficient and effective manner.