• Journal of Industrial Convergence
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• v.2 no.1
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• pp.159-186
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• 2004

One of the biggest change in the distributive market recently is that the development of private brand is progress actively since consumers purchasing behavior is tend to shift to resonable and practical planned purchase from brand image or brand name. Once the development of private brands is done successfully, the independent merchandising distinguished from other distribution companies is established, store image through customer satisfaction is strengthen and volume of sales and profit are increased. However, the existing studies in this field have not dealt with this matter systematically. Therefore, the purpose of this study is to propose an integrated framework within which to view private brand proneness. Factors found to influence private brand proneness included perceived cost, with private brand, perceived value for money, store fame, perceived risk, perceived quality variation between national and private brand products. Foe empirical analysis, the data were collected from 211 consumers who purchased the private brands in discount store and department store. With the collected survey data, reliability test, factor analysis for validity test and regression analysis for hypotheses test were conducted. Most hypotheses were accepted but on hypotheses were rejected negative relation of perceived cost and private brand proneness. Research results indicate that private brand proneness is affected by perceived value, perceived fame and there are negative relation between private brand proneness and perceived quality variation.

• Tribology and Lubricants
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• v.39 no.3
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• pp.94-101
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• 2023

Automotive wheel bearings are a critical component of vehicles that support their weight and facilitate rotation. Life and stiffness are significant performance characteristics of wheel bearings. Designing wheel bearings involves finding optimal design variables that satisfy both performances. CO₂ emission reduction and fuel efficiency regulations attribute to the recent increase in design requirements for lightweight and compact automotive parts while maintaining performance. However, achieving a design that maintains performance while reducing weight poses challenges, as performance and weight are generally inversely proportional. In this study, we perform design optimization of automotive wheel bearings considering life and stiffness. We develop a program that calculates the basic rated life and modified rated life based on international standards for evaluating the life of wheel bearings. We develop a regression equation using regression analysis to address the time-consuming stiffness analysis during repetitive analysis. We perform ANOVA and main effect analyses to understand the statistical characteristics of the developed regression equation. Furthermore, we verify its reliability by comparing the predicted and test results. We perform design optimization using the developed life prediction program, stiffness regression equation and weight regression equation. We select bearing specifications and geometry as design variables, weight as the cost function, and life and stiffness as constraints. Through design optimization, we investigate the influence of design variables on the cost function and constraints by comparing the initial and optimal design values.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.26-32
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• 2016

Usually, there are many uncertainties regarding the error of an assumed load, material properties, member size, and structure analysis in a structure, and it may have a direct influence on the qualities of optimal design of structures. Probabilistic analysis has developed rapidly into a desirable process and structural reliability analysis is an increasingly important tool that assists engineers to consider uncertainties during the design, construction and life of a structure to calculate its probability of failure. This study deals with the applications of two optimization techniques to solve the reliability-based optimization problem of structures. The reliability-based optimization problem was formulated as a minimization of the structural volume subject to the constraints on the values of componential reliability index determined by the AFOSM approach. This presented method may be a useful tool for the reliability-based design optimization of structures.

• Journal of Applied Reliability
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• v.18 no.2
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• pp.114-121
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• 2018

Purpose: This study proposes a process for evaluating the preventive maintenance policy for a system with degradation characteristics and for calculating the appropriate preventive maintenance cycle using time- and condition-based maintenance. Methods: First, the collected data is divided into the maintenance history lifetime and degradation lifetime, and analysis datasets are extracted through preprocessing. Particle filter algorithm is used to estimate the degradation lifetime from analysis datasets and prior information is obtained using LSE. The suitability and cost of the existing preventive maintenance policy are each evaluated based on the degradation lifetime and by using a minimum repair block replacement model of time-based maintenance. Results: The process is applied to the degradation of the reverse osmosis (RO) membrane in a seawater reverse osmosis (SWRO) plant to evaluate the existing preventive maintenance policy. Conclusion: This method can be used for facilities or systems that undergo degradation, which can be evaluated in terms of cost and time. The method is expected to be used in decision-making for devising the optimal preventive maintenance policy.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.4
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• pp.460-466
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• 2018

With the development of information technology, the scale of computer software system is constantly expanding. Reliability and cost of software development have a great impact on software quality. In this study, based on the software failure interval time data, a comparative analysis was performed on the characteristics of the software development cost model based on the lifetime distribution following the Type-2 Gumbel and Erlang distribution in the NHPP model. As a result, the trends of the cost curves for the Go-Okumoto model and the proposed Erlang model and the Type-2 Gumble model both decreased in the initial stage and gradually increased in the latter half of the failure time. Also, Comparing the Erlang model with the Type-2 Gumble model, we found that the Erlang model is faster and more cost-effective at launch. Through this study, Software operators should remove possible defects from the testing phase rather than the operational phase to reduce defects after the software release date, it is expected to be able to study the prior information needed to understand the characteristic of software development cost.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.5
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• pp.935-944
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• 2023

In this study, the Inverse-type (: Inverse-Exponential, Inverse-Rayleigh) life distribution, which is known to be suitable for reliability research, was applied to a software development cost model based on finite failure NHPP(: Nonhomogeneous Poisson Process), and then the attributes that determine the model's performance were analyzed. Additionally, to evaluate the efficiency of the model, it was compared with the Goel-Okumoto basic model. The performance of the model was analyzed using failure time data, and MLE (: Maximum Likelihood Estimation) was applied to calculate the parameters. In conclusion, first, as a result of analyzing m(t), which determines the development cost, the Inverse-Exponential model was efficient due to its small error in the true value. Second, as a result of analyzing the release time along with the development cost, the Inverse-Rayleigh model was confirmed to be the best. Third, as a result of comprehensive evaluation of the attributes (m(t), cost, and release time) of the proposed model, the Inverse-Rayleigh model had the best performance. Therefore, if software developers can effectively utilize this research data in the early process, they will be able to proactively explore and analyze attributes that affect cost.

• Journal of the Korean Solar Energy Society
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• v.23 no.4
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• pp.11-20
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• 2003

This study aims to develop the program for active solar heating system design & analysis. The program, named ASOLis, is consisted of three user's interface like as system input/output, library, and utilities and used TRNSYS as a calculation engine for the system analysis. ASOLis simplifies user's input data through the database and can design 37 different types of solar systems. Solar system is configurated by two separated parts "solar thermal collecting part" and "load supplying part". Due to the user-friendly layout, all design parameters can be changed quickly and easily for the influence on system efficiency. For the reliability, ASOLis compared with experimental result. As a result, ASOLis is expected to be used as a vital tool for the design and analysis of active solar heating system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.3
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• pp.43-49
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• 2013

Recently harmonics flowing into power system is increasing as the usage of semiconductor equipments and switching mode power equipments are increasing. Harmonics cause problems such as heat increasing and reduction in capacity of transformers, especially the harmonics flowing into a distribution transformer can lead to the lifetime reduction of transformer. In this paper, we are about to develop a device that can monitor harmonics in real-time as it is affixed to a distribution transformer. Unlike the existing expensive harmonic analysis device, a new harmonic analysis algorithm is proposed in order to implement low-cost equipment. The real-time harmonic analysis algorithm proposed in this paper allows implementation on low performance microcontrollers, thus it can monitor the harmonic in real-time as it is individually affixed to the transformer. Therefore, it would improve the reliability of the transformer and stable power system operation would be possible as it can prevent the transformer accidents in advance.

• Journal of Korean Academy of Nursing Administration
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• v.10 no.1
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• pp.25-36
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• 2004

Purpose: Nursing puts much weight en the organization of hospital. Therefore it is necessity to improve nursing care. One of the most important things is to secure confident nurses and to develop nurse' potentiality. It directs nurse evaluation system. The concept of "performance appraisal tools" is extremely important in evaluation system. Therefore, the purpose of this study aims to define performance appraisal process. Method: In order to do this, two main study has been observed interviewing appraisers and employees in-depth and analyzing performance appraisal tools of seven hospitals and analysed validity, reliability, acceptability and practicability. Result: The result of this study can be summarized as follows; Firstly, the result of analysis of performance appraisal tools. Regard to validity, Hospitals had a typical goal, but had not put to practice use. Regard to reliability, 1) Appraisal rule had been focused on appraiser's error, how to avoid. 2) 5 hospitals accessed nurses with relative rating and 2 hospitals with absolute rating both in practice. 3) 3 hospitals informed nurses the result of performance appraisal but 4 hospitals did not. 4) All hospitals in this study had conducted superiors rating. Regard to acceptability, 1)Rating scale method had been implemented by 6 hospitals and among those conducted beth ranking method and descriptive method. 2) Most hospitals had focused on personal traits in performance appraisal factors. Regard to practicality, The term of appraisal took $10{\sim}14$ days; performance appraisal happened 1 or 2 times per year; appraisal factors were based on 10 different items. Secondly, the result of in-depth interview with head nurses and staff nurses Regard to validity, head nurses and nurses wared that the goal of performance appraisal is to develop nurse's ability. Regard to reliability, head nurses pointed out that they were doubt of the justice of performance appraisal and they should have got training. Nurses insisted that raters should have been trained due to lack of qualification of appraiser; Head nurses and nurse proposed to convert form relative rating to absolute rating; to inform the result of appraisal; to implement peers rating. Regard to acceptability, One of the critical problems of performance appraisal tools was abstract of appraisal factors ; Lack of job analysis. Regard to practicality, Head nurses used to take overtime for appraisal. There was only a little respond despite of their efforts. Nurses questioned that appraisal tools exist for only appraisal; there was less cost-effectiveness. Conclusion: Based en these findings, it could be suggested to improve the performance appraisal tools for nurses evaluation. Firstly, it is necessary to describe goal of performance appraisal clearly set up, so that nurses could improve their positive word performance and develop their potentiality. Secondly, it is necessary to obtain various training on raters, implement absolute rating and inform the result of appraisal to nurses and use peers rating. Thirdly, it is necessary to convert from rating scale method to management by objectives or behaviorally anchored rating scale and take measurable appraisal factors based en job analysis. Finally, it is necessary to reduce the appraisal cost but increase effectiveness of performance appraisal.

• Journal of Digital Convergence
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• v.12 no.5
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• pp.139-148
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• 2014

In recent years, computational models using parametric estimation method have been developed and used widely for efficient cost analysis. In this research, by applying experienced data from Guidance and Control Systems in Missile System field, the cost analysis for engineering model and commercial computational model(Price H, HL, M, S) are conducted and its result is analysed, so that the difference between two models and its grounds are apprehended. Comparing the calibrated value of computational model based on the data base of similar equipment and the cost from the engineering estimation, the two results are very close. It means that the credibility of data is enhanced through calibration. Also, for cost analysis of similar components in the future, the method for calibration of the computational models is also examined. When estimating development cost in this research, although many parts have been estimated through uncertain elements, the reliability could have been enhanced by applying computational model which secures objectivity. It is a very reasonable estimation method by utilizing calibration of the computational models based on existing accumulated development data.