• Journal of the Korean Society of Systems Engineering
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• v.19 no.2
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• pp.46-58
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• 2023

Deterministic safety analysis is a crucial part of safety assessment, particularly when it comes to demonstrating the safety of nuclear power plant designs. The traditional approach to deterministic safety analysis models is to model the nuclear core using point kinetics. However, this simplified approach does not fully reflect the real core behavior with proper moderator and fuel reactivity feedbacks during the transient. The use of Multi-Physics approach allows more precise simulation reflecting the inherent three-dimensionality (3D) of the problem by representing the detailed 3D core, with instantaneous updates of feedback mechanisms due to changes of important reactivity parameters like fuel temperature coefficient (FTC) and moderator temperature coefficient (MTC). This paper addresses a CEA ejection accident at hot full power (HFP), in which the underlying strong and un-symmetric feedback between thermal-hydraulics and reactor kinetics exist. For this purpose, a multi-physics analysis tool has been selected with the nodal kinetics code, 3DKIN, implicitly coupled to the thermal-hydraulic code, RELAP5, for real-time communication and data exchange. This coupled approach enables high fidelity three-dimensional simulation and is therefore especially relevant to reactivity initiated accident (RIA) scenarios and power distribution anomalies with strong feedback mechanisms and/or un-symmetrical characteristics as in the CEA ejection accident. The Systems Engineering approach is employed to provide guidance in developing the work in a systematic and efficient fashion.

• Fashion & Textile Research Journal
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• v.16 no.5
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• pp.776-784
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• 2014

KS K 0051(2009) was established in 1990 and revised in 1994, 1999, 2004 and 2009. Recently the structure of apparel production and distribution are changing like as small quantity batch production, increase of importing abroad apparel and increase of on-line shopping mall. Based on Social and economic conditions, examine the potential for use of KS K 0051(2009) standard sizing system for female adult's garments are needed. Through which, it was intended to suggestion for the revision of standard sizing system for female adult's garments which can facilitate communication among consumer, producer and sellers. The improvement point was discussed through review of the current KS K 0051 (2009) and abroad standard sizing system for female adult's garments, ISO 3637(1977), ISO 4416(1981), BS EN 13402-2(2002), BS EN 13402-3(2004), JIS L 4005(2001) and GB/T 1335.2(2008). Also, the revision of standard sizing system for female adult's garments was suggested using data of 6th Size Korea. As a result of this study, in the revision, formal wear, casual wear, training wear and under wear were separated to simplify the classification and the classification of body type were excluded. Also, it is possible that size designation was simplified through optional notation and letter code based on bust girth could be marked together in casual wear.

• Korean Management Science Review
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• v.11 no.2
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• pp.1-27
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• 1994

A reliability data processing MPRDP (Multi-Purpose Reliability Data Processor) has been developed in FORTRAN language since Jan. 1992 at KAERI (Korean Atomic Energy Research Institute). The purpose of the research is to construct a reliability database(plant-specific as well as generic) by processing various kinds of reliability data in most objective and systematic fashion. To account for generic estimates in various compendia as well as generic plants' operating experience, we developed a 'three-stage' Bayesian procedure[1] by logically combining the 'two-stage' procedure[2] and the idea for processing generic estimates[3]. The first stage manipulates generic plant data to determine a set of estimates for generic parameters,e.g. the mean and the error factor, which accordingly defines a generic failure rate distribution. Then the second stage combines these estimates with the other ones proposed by various generic compendia (we call these generic book type data). This stage adopts another Bayesian procedure to determine the final generic failure rate distribution which is to be used as a priori distribution in the third stage. Then the third stage updates the generic distribution by plant-specific data resulting in a posterior failure rate distribution. Both running failure and demand failure data can be handled in this code. In accordance with the growing needs for a consistent and well-structured reliability database, we constructed a generic reliability database by the MPRDP code[4]. About 30 generic data sources were reviewed and available data were collected and screened from them. We processed reliability data for about 100 safety related components frequently modeled in PSA. The underlying distribution for the failure rate was assumed to be lognormal or gamma, according to the PSA convention. The dependencies among the generic sources were not considered at this time. This problem will be approached in further study.

• Journal of the Korean Society of Systems Engineering
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• v.16 no.2
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• pp.97-109
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• 2020

On March 11, 2011, an earthquake followed by a tsunami caused an extended station blackout (SBO) at the Fukushima Dai-ichi NPP Units. The accident was initiated by a total loss of both onsite and offsite electrical power resulting in the loss of the ultimate heat sink for several days, and a consequent core melt in some units where proper mitigation strategies could not be implemented in a timely fashion. To enhance the plant's coping capability, the Diverse and Flexible Strategies (FLEX) were proposed to append the Emergency Operation Procedures (EOPs) by relying on portable equipment as an additional line of defense. To assess the success window of FLEX strategies, all sources of uncertainties need to be considered, using a physics-based model or system code. This necessitates conducting a large number of simulations to reflect all potential variations in initial, boundary, and design conditions as well as thermophysical properties, empirical models, and scenario uncertainties. Alternatively, data-driven models may provide a fast tool to predict the success window of FLEX strategies given the underlying uncertainties. This paper explores the applicability of Artificial Intelligence (AI) to identify the success window of FLEX strategy for extended SBO. The developed model can be trained and validated using data produced by the lumped parameter thermal-hydraulic code, MARS-KS, as best estimate system code loosely coupled with Dakota for uncertainty quantification. A Systems Engineering (SE) approach is used to plan and manage the process of using AI to predict the success window of FLEX strategies under extended SBO conditions.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.1
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• pp.22-33
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• 2004

The purpose of this study was to investigate the differences of lifestyle and clothing behavior of high school girls according to their residential area. The focus group interview was executed with 29 high school students and picture analysis was carried with 400 pictures of their outfits on weekends. The results show that they borrow their clothing one another taking turns, and there has lesibean dress code in common regardless of residential area. Students residing in Seoul wear brand products, and buy at department store, discount store and the stores in Myongdong or Sinchon, while students residing in Inchon wear Bose products, and buy at the stores in subway. Most of adolescents wear easy casual, and those of Inchon sometimes wear formal with high heel and young character casual, and often wear make up and get hair permanant/dyeing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.4
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• pp.207-215
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• 2014

Password based authentication systems are most widely used for user convenience in web services. However such authentication systems are known to be vulnerable to various attacks such as password guessing attack, dictionary attack and key logging attack. Besides, many of the web systems just provide user authentication in a one-way fashion such that web clients cannot verify the authenticity of the web server to which they set access and give passwords. Therefore, it is too difficult to protect against DNS spoofing, phishing and pharming attacks. To cope with the security threats, web system adopts several enhanced schemes utilizing one time password (OTP) or long and strong passwords including special characters. However there are still practical issues. Users are required to buy OTP devices and strong passwords are less convenient to use. Above all, one-way authentication schemes generate several vulnerabilities. To solve the problems, we propose a multi-channel, multi-factor authentication scheme by utilizing QR-Code. The proposed scheme supports both user and server authentications mutually, thereby protecting against attacks such as phishing and pharming attacks. Also, the proposed scheme makes use of a portable smart device as a OTP generator so that the system is convenient and secure against traditional password attacks.

• Journal of the Korea Fashion and Costume Design Association
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• v.10 no.1
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• pp.99-116
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• 2008

This study reviewed pertinent literature and examined relics of manggon(a headband worn to hold a man's topknot hair in place), donggot(a topknot pin), and chigwan(a topknot cover). Before the modernized short hair style, wearing a gat was an important custom. Therefore, manggon, which was used to hold a man's hair in place under the gat, was considered an essential part of the man's official dress code. Donggot is a pin that held the topknot hair in place. It was a must have for a married man, like the binyeo, a lod-like hairpin, for a married woman. Unlike gwanja, it had nothing to do with official rank, but materials were of a variety of materials, including jade and gold. The structure of the donggot was studied in three parts-head, neck and body. Major forms for the head include the mushroom, bean and ball. Bullet and half-cut bullet forms were also found. Forms for the neck include straight-neck and curved-neck. A neck with a belt around a double chin was also found. Forms for the body include the tetrahedron, octahedron and cylinder. The most popular form for silver and white bronze donggot heads was the mushroom, followed by bean and pile forms. Chigwan is also called chipogwan, chichoal, choalgyesogwan, noingwan and sangtugwan. In poetry it was called chichoal, and it used to be called taegogwan in the past as well. Chigwan was so small that it managed to hold a topknot. According to confucian custom in the Joseon period, by wearing chigwan, men didn't display their bare topknot even when they didn't dress up. When they went out, they wore another official hat over the chigwan.

• The Research Journal of the Costume Culture
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• v.26 no.4
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• pp.485-502
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• 2018

In this research, we conducted an empirical study using the theory of sociologist Jean Baudrillard to examine the phenomenon of contemporary people in Korea acquiring tattoos. The researcher classified the consumption behavior of modern society, as described by Baudrillard in The Consumer Society, into three keyword phrases: consumption by personal taste, coded consumption, and recyclage of consumption. Using this as the premise of the study, 18 men and women in their 20s and 30s completed questionnaires and interviews, and the results supported labeling tattoo consumption as consumption by personal taste, tattoos as coded consumption, and recyclage of tattoo consumption, similar to the consumption pattern that Baudrillard sees. First, the younger generations have consumed tattoos according to their personal preferences. They express themselves by tattooing for self-complacency, self-marking, pursuing individuality, overcoming the appearance complex, and seeking pleasure. Second, they have consumed socially coded tattoos. They say that tattoos domestically act as negative codes and symbolize individuals. Although tattoos are a symbol of artists who are relatively free from social norms, they are still a symbol of social misfits created as such by negative perceptions. Third, the pattern of tattoo consumption is like that of contemporary consumption. Tattoos already have become part of popular culture in Korea, and there has been a changing trend in tattoo culture. This study has significance in that tattoos were regarded as a consumption behavior that deviated, from the perspective of deviance. That phenomenon of today's tattoo culture of today was confirmed through the empirical study.

• Fashion & Textile Research Journal
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• v.8 no.2
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• pp.183-190
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• 2006

The purpose of this study was to analyze social, economic and cultural phenomena of the luxury brand in the viewpoint that the consumption system of the modern society stood for the sign consumption and the industrial production of difference as Baudrillard mentioned in the Consumer Society. The result was divided into the two subjects popularization and differentiation of luxury brand. Firstly the meaning of luxury brand was that the personal effects of consumption of king or aristocratic class who did not exist in the modern and were made into the selection and consumption-possible things of exchange value. The popularization of this sign was accelerated through TV drama. Secondly as differentiation strategy of luxury brand, was made by giving meaning to the life style concept of the upper class with advertisement and design, and also the logo of design was used as sign differentiated from people. Also the reason why the producer of the luxury brand gave meaning to such life style was that the awareness of the brand which people have consistently makes them consume more products. The consumption system of the modern society stood for the sign consumption, difference sign mark value which was the desire on a social meaning basis, not the consumption of things as used value. And the consumer could express his personality by selecting and consuming the product of luxury brand model made with this sign. Accordingly the distribution, purchase, sales and acquisition of the things with this difference sign were our verbal activity and linguistic code today, and it was the essential feature of the society, culture and economy of the consumer society.

• Journal of Navigation and Port Research
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• v.36 no.10
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• pp.845-849
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• 2012

The next-generation wireless communication requires fast transmission speeds with various services and high reliability. In order to satisfy these needs we study MIMO system used layered space time coded system (LST) combining space time trellis codes (STTC) with turbo codes. In LST, two codes that are inner and outer codes are concatenated in the serial fashion. The inner codes are turbo Pi codes suggested in DVB-RCS NG system, and outer codes are STTC codes proposed by Blum. The interleaver technique is used to efficiently combine two codes. And we proposed and simulated that a full iteration method between turbo decoder and BCJR decoder to improve the performance instead of only processing inner-iteration turbo decoder. The simulation results of proposed effective layered method show improving BER performance about 1.3~1.5dB than conventional one.