• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.63
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• pp.33-43
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• 2001

To estimate the reliability of a large and complex network with a small variance, we propose two dynamic Monte Carlo sampling methods: the sequential minimal cut set (SMCS) and the sequential minimal path set (SMPS) methods. These methods do not require all minimal cut sets or path sets to be given in advance and do not simulate all arcs at each trial, which can decrease the valiance of network reliability. Based on the proposed methods, we develop the importance sampling estimators, the total hazard (or safety) estimator and the hazard (or safety) importance sampling estimator, and compare the performance of these simulation estimators. It is found that these estimators can significantly reduce the variance of the raw simulation estimator and the usual importance sampling estimator. Especially, the SMCS algorithm is very effective in case that the failure probabilities of arcs are low. On the contrary, the SMPS algorithm is effective in case that the success Probabilities of arcs are low.

• Korean System Dynamics Review
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• v.13 no.2
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• pp.73-91
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• 2012

This study aims to comprehensively understand the dynamics between the factors related to service quality, satisfaction and reuse intention. The contents of the study are as follows. First, it draws the limitations of the existing studies by reviewing the literature related to the relationships between service quality, satisfaction and reuse intention. Second, it highlights the characteristics of System Dynamics as a means of overcoming their shortcomings as well as examining the dynamic mechanism of the relevant factors. Third, it explores the feedback loops of the relevant key variables and the feedback structure of the system. Lastly, it concludes with the suggestions and implications of the key research findings. This study is expected to emphasize the importance of the feedback mechanism operating around the service quality, satisfaction, and reuse intention. Further, the causal loop diagram developed can be a basic material for the diverse levels of governments as well as service providers to refer to for improving the service quality of Community Social Service Investment Program.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.6
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• pp.59-72
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• 2002

Along with the enlargement of WTO, issues about standardization activity are more and more become concerning object worldwide. Countries launch the work that putting the standardization in order, such as re-establishing their standardization strategy. With the chance of entering WTO, China is promoting the rebuilding of standardization system in order to conform to international standardization system. Thus, in this paper, research make it clear that the variation of circumstance of standardization activity, the importance of the standardization activity, and the international movement, in the meantime, it surveyed the development course of standardization activity and it's present operating system. By this means, it concludes the problems of present operating system and implies the improving scheme. Further more, this paper implies Chinese characteristic standardization system which conform with WTO/TBT and international standardization system. Firstly, through the comprehensive analysis on standardization system, it figures out the main function of relevant organizations in each working stage. Secondly, this paper makes a system model composed of possible three stage, and setup items needs promotion and main target in each stage. Finally, this paper point out the development direction of standardization system, it also implies it's limitation and the later possible research topic in this field.

• Journal of Information Technology Services
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• v.15 no.4
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• pp.63-72
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• 2016

Critical infrastructure has been operating in a closed environment with a completely separate information system and in the private area. However, with the current ICT environment changes due to convergence and open platforms it has increased the threats and risks to critical infrastructure. The importance of cyber security is increasing in the infrastructure control system, such as the outbreak of Ukraine blackout in 2015 by a malicious code called 'black energy'. This thesis aims to recognize the importance and necessity of protecting the critical infrastructure service, designing a security framework reflecting environmental and characteristic changes, and analyzing the management system suitable for a security framework. We also propose a theoretical basis for constructing a new security framework by comparing and analyzing seven international security management system standards, such as NIST 800-82 and IEC 62443-2-1, which are used in the control system. As a result, the environment surrounding critical infrastructure changes with the characteristics of connectivity, openness, and finality was studied, and as a response to this, many scholars and institutions present critical infrastructure security frameworks as cycle enhancement type structures, risk management structures, and management domain expansion structures. In response, the security framework encompassing these structures, CISF (Critical Infrastructure Security Framework), was designed. Additionally, through the security related international standard and criterion analysis, as a newly designed security standard suitable for CISF, IEC 62443-2-1 is reviewed and suggestions are made.

• The Journal of Information Systems
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• v.15 no.2
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• pp.95-123
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• 2006

It is needed to evaluate information systems actively which has already developed to improve future performance of the organization and foster the activation of information system. The introduction or development of information system also can bring about a organizational success. To measure exactly the organizational performance of information systems, it is needed to develop a new valuation model for a specific information system from a objective pint of view, as well as to equip a standard methodology using BSC measurement. The information system valuation from a objective point of view is of importance as the basic information for the decision to obtain information system. This paper takes aim at investigating a new information system valuation model and developing a information system valuation system using case-based reasoning for predicting currency value of information system in each organization. A new information system valuation system is developed as a web-enabling base. Using this, users are able to estimate the value of specific information system on a real time efficiently.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.195-201
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• 2008

LCD Enterprises introduce quality management strategy to survive in rapid change of production situation. Especially in LCD industry, competitiveness is more needed ever before in the decrease of investment resulted from frequent business fluctuations and in the appearance of the third competitor. In order to overcome this situation, the quality cost system should be implemented as it is suited to a company, but few companys introduce and apply the quality cost system in LCD industry. Thus, Critical factors for outstanding LCD company to apply successfully quality cost system are studied in this paper. The level of importance of the factors is measured be weighted value analysis and a way to maximize the effect of applying quality cost system in LCD industry is proposed by the order of importance.

• Journal of Information Technology Services
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• v.4 no.1
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• pp.141-148
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• 2005

The importance of education is greatly emphasized in the IT era. However, teachers have to deal with teaching work as well as increasing non-educationalchores. One of those chores is student counseling. Nowadays, teachers have considerable difficulty in consulting students because they cannot visit their home and don't have enough information on students. Furthermore, students are not willing to participate in school counseling since they think school counseling is not of much help and is just time-consuming. Most of the current school counseling is focused on matters related to entrance into a school of higher grade such as choice of college. But, students need counseling on matters regarding their ordinary life. This paper suggests a web-based student-counseling system that may solve this problem. The paper identifies core requirements for the web-based student-counseling system, discusses its design and implementation and shows it is more effective than the current ordinary school counseling by experimenting on a group of students with this system.

• Steel and Composite Structures
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• v.32 no.3
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• pp.305-312
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• 2019

In this study, we investigated the effect of fatigue crack propagation of the beams which have a vital importance in engineering applications, on the natural frequency of the system. Beams which have a wide range of applications, are used as fundamental structural elements in engineering structures. Therefore, early detection of any damages in these structures is of vital importance for the prevention of possible destructive damages. One of the widely used methods of early detection of damages is the vibration analysis of the structure. Hence, it is of vital importance to detect and monitor any changes in the natural frequencies of the structure. From this standpoint, in this study we experimentally investigated the effect of fatigue crack propagation on beams produced from 4140 steel, of the natural frequency of the beam. A crack was opened on the $8{\times}16{\times}500mm$ beam using a 3 mm long and 0.25 mm wide wire erosion. The beam, then, underwent 3 point bending tests at 10 Hz with a dynamic fatigue device and its natural frequencies were measured in scheduled intervals and any changes taking place on the natural frequencies of the beam were measured. This data allowed us to identify and measure the crack occurring on the beam subjected to dynamic loading, during the propagation phase. This method produced experimental data. The experimental data showed that the natural frequency of the beam decreased with the propagation of the fatigue crack on the beam.

• Korean Security Journal
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• no.57
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• pp.137-156
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• 2018

The purpose of this study is to analyze the current status of counter terrorism system and to identify the causes of problems and to suggest alternatives by selecting legal and operational sectors based on theories of open systems and integrated systems. According to the results of the research, first, the degree of agreement on the open system and the integrated system is low with regard to the characteristics of the counter-terrorism system. Second, in relation to the importance and necessity of major factors of construction and operation of counter-terrorism system, counter-terrorism workers recognize that it is the most important and necessary. In the case of strengthening international cooperative system, the difference of recognition between importance and necessity was the biggest. The importance and necessity of reviewing the Anti-Terrorism Act for the protection of the public and public safety were relatively low, and the cooperation with the private sector showed the lowest importance and necessity. In the case of academic achievement, the average level of high school graduates is higher than that of professional high school graduates. Therefore, this research concludes that counter terrorism operation system with open and integrated system has to be applied to national counter terrorism operation structure in South Korea in increasing the quality and efficiency of nation counter terrorism response capability.

• The Korean Journal of Food And Nutrition
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• v.30 no.3
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• pp.413-426
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• 2017

The study subjects were 302 adult males and females aged more than 20 years living in the metropolitan area of South Korea. This study was conducted to obtain baseline data to establish proper development and marketing strategies by examining the effects of food-related lifestyles on the importance of diet, purchasing behavior towards diet lunch boxes, and their selected attributes such as menu, packaging, and services. With respect to food-related lifestyle, a cluster analysis was performed by using five factors such as convenience factor, health factor, safety factor, taste factor, and economy factor obtained from factor analysis to derive the economy type, the taste and economy type, the convenience type, the safety type, and the health type. As a result, the respondents regarded 'food hygiene (4.59)', 'freshness (4.47)', 'taste (4.28)', and 'nutrient balance (4.19)' as the selected attributes of diet lunch box menus. Moreover, the importance of diet lunch box menus (${\beta}=0.179$) was increased with increasing safety orientation. 'Shelf life label (4.42)' was the most important selected attribute of diet lunch boxes, followed by 'ingredient label (4.19)', 'nutrition facts label (4.16)', and 'indication of origin (4.15)'. In particular, the importance of packaging for diet lunch boxes (${\beta}=0.203$) was increased with increasing safety orientation. With respect to the selected attributes of services in purchasing diet lunch boxes, 'provision of personalized menus (4.07)' was the most important, and the importance of services for diet lunch box (${\beta}=0.160$) was increased with increasing taste and economy orientation. Based on the above results, the respondents gave importance to the selected attributes related to food safety and health such as hygiene and, freshness. In addition, they also placed emphasis on hygiene and safe factors such as shelf life, ingredients, and nutrition facts labels. Therefore, it is considered necessary to develop diet lunch boxes by taking these factors into account. Furthermore, in services for diet lunch boxes, it is considered necessary to establish a service system capable of providing consumers with specialized menu or nutrition counseling according to the food-related lifestyle for their proper health management. Particularly, because consumers place emphasis on both food hygiene and safety, and health, it is considered necessary to thoroughly manage hygiene, safety, and nutrition in menu or packaging so that it is possible to enhance customer satisfaction by considering these selected attributes in greater detail.