• International Journal of Fluid Machinery and Systems
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• v.2 no.1
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• pp.61-71
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• 2009

Machine fault diagnostic and prognostic techniques have been the considerable subjects of condition-based maintenance system in the recent time due to the potential advantages that could be gained from reducing downtime, decreasing maintenance costs, and increasing machine availability. For the past few years, research on machine fault diagnosis and prognosis has been developing rapidly. These publications covered in the wide range of statistical approaches to model-based approaches. With the aim of synthesizing and providing the information of these researches for researcher's community, this paper attempts to summarize and classify the recent published techniques in diagnosis and prognosis of rotating machinery. Furthermore, it also discusses the opportunities as well as the challenges for conducting advance research in the field of machine prognosis.

• Korean Journal of Child Studies
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• v.30 no.6
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• pp.391-403
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• 2009

This study examined the concept and status, research issues, and pragmatic and policy issues of school-dropout adolescents. As the number of school-dropout adolescents has been increasing in Korea since 2006, more attentions have been given to these adolescents academically, intervention and policy-wise. Some of the research topics on them include types of school-dropouts, their socio-environmental factors, and reasons for the increase of school-dropouts. In reality, the government is required to provide them with opportunities to cope with their dropping out of schools by preparing the career guidance for them and to resolve the issues of their returning to or continuing in school education and their welfare.

• Journal of Families and Better Life
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• v.28 no.4
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• pp.77-87
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• 2010

The purpose of this research was to explore Korean-Chinese women's experiences of family separation. A qualitative approach was used to analyze the in-depth interviews with 14 Korean-Chinese women who lived away from their families in China. Korean-Chinese women showed the child-centered family values. The main reason of family separation was to provide children of better educational opportunities. Korean-Chinese women, their husbands, and their extended family members worked as a team to support children. Their cohesive family relationships reflected the unique sociocultural context of Korean-Chinese society. Family separation seems to be normalized for the purpose of child education. The research would contribute to understand how family values affect family life style.

• International Journal of Costume and Fashion
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• v.13 no.1
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• pp.49-59
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• 2013

This research study investigates the cultural significance and meaning of Thai Mudmee, their historical content, and the variety of the Thai Mudmee techniques, including patterns, symbol and colours. The aim has been to develop the traditional pattern and designs of the Thai Mudmee and produce contemporary textile pieces more appropriate for modern lifestyle tastes both in Thailand and Internationally. By reviving the Thai weaving tradition it is also hoped to encourage and maintain the continuous survival of tradition Mudmee, providing new sales opportunities and markets both in Thailand and abroad. Studying various attempts to redevelop traditional crafts in different countries brought to me the idea of how to develop folk crafts, the problems that occur in this area have encouraged me to express how folk crafts could be benefit from the design process. In this thesis I also express my recommendations for other researchers and the Thai government, as well as other people who interested in Mudmee design. The thesis concludes with the possibilities of how to improve the design of the Mudmee fabric and further areas of research.

• Korean Journal of Animal Reproduction
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• v.23 no.4
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• pp.381-391
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• 1999

During the last 20 years, transgenic animal technology has provided revolutionary new opportunities in many aspects of agriculture and biotechnology. Several gene delivery systems including pronuclear injection, retroviral vectors, sperm vectors, and somatic cell cloning have developed for making transgenic animals. In the future major improvements in transgenic animal generation will be mainly covered by somatic cell cloning technology. Many factors affecting integration frequency and expression of the transgenes should be overcome to facilitate the industrial applications of transgenic technology. Transgenic animal technology has settled down in some areas of the biotechnology, especially the mass production of valuable human proteins and xenotransplantation. In the 21st century animal biotechnology will further contribute to welfare of human being.

• Journal of information and communication convergence engineering
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• v.9 no.3
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• pp.341-346
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• 2011

Wireless sensor networks (WSNs) are formed by a great quantity of sensor nodes, which are consisted of battery-powered and some tiny devices. In WSN, both efficient energy management and Quality of Service (QoS) are important issues for some applications. Real-time services are usually employed to satisfy QoS requirements in critical environment. This paper proposes a real-time MAC (Medium Access Control) protocol with extended backoff scheme for wireless sensor networks. The basic idea of the proposed protocol employs (m,k)-firm constraint scheduling which is to adjust the contention window (CW) around the optimal value for decreasing the dynamic failure and reducing collisions DBP (Distant Based Priority). In the proposed protocol, the scheduling algorithm dynamically assigns uniform transmitting opportunities to each node. Numerical results reveal the effect of the proposed backoff mechanism.

• Journal of the Korean Operations Research and Management Science Society
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• v.31 no.3
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• pp.81-96
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• 2006

We consider a rental company that dynamically manages Its capacity level through capacity addition and return While serving customer with its own capacity, the company expands its capacity by renting items from an outside source so that it can avoid lost opportunities of rental which occur when stock is not sufficient. If stock becomes sufficiently large enough to cope with demands, the company returns expanded capacity to the outside source. Formulating the model into a Markov decision problem, we identify an optimal capacity management Policy which states when the company should expand its capacity and when it should return expanded capacity after capacity addition. Since it is intractable to analytically find the optimal capacity management policy and the optimal size of capacity expansion, we present a numerical procedure that finds these optimal values based on the value iteration method. Numerical analysis is implemented and we observe monotonic properties of the optimal performance measures by system parameters, which are meaningful in developing effective heuristic policies.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.19-19
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• 2003

The injection of spins into nonmagnetic semiconductors has recently attracted great interest due to the potential to create new classes of spin-dependent electronic devices. A recent strategy to achieve control over the spin degree of freedom is based on dilute ferromagnetic semiconductors. Ferromagnetism has been reported in various semiconductor groups including II-Ⅵ, III-V, IV and II-IV,-V$_2$, which will be reviewed. On the other hand, to date the low solubility of magnetic ions in non-magnetic semiconductor hosts and/or low Curie temperature have limited the opportunities. Therefore the search for other promising ferromagnetic semiconducting materials, with high magnetic moments and high Curie temperatures (Tc), is of the utmost importance. In this talk, we also introduce new pure ferromagnetic semiconductors, MnGeP$_2$ and MnGeAs$_2$, exhibiting ferromagnetism and a magnetic moment per Mn at 5K larger than 2.40 ${\mu}$B. The calculated electronic structures using the FLAPW method show an indirect energy gap of 0.24 and 0.06 eV, respectively. We have observed spin injection in MnGeP$_2$ and MnGeAs$_2$ magnetic tunnel junctions through semiconducting barriers.

• Journal of the Korea Fashion and Costume Design Association
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• v.18 no.3
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• pp.213-228
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• 2016

This study is performed the design and production of the real hotel uniforms around the actual case. The purpose of the study is to research and develop the uniform design which is partially utilized for image integration. After reviewing and making up a theoretical background of general hotel uniforms, we designed I hotel's uniforms based on the uniform design process. Research Scope of uniform design is up to the development of it for practicians who have many opportunities to meet customers directly at front desk, banquet reservation office and restaurant. Based on logo of company C.I.(Corporate Identity) and symbol colors, the concept and an illustration according with I hotel are drawn up. Also design is planed and a real is produced. This like objective design development becomes the basis for building a uniform image suitable for C.I.(Corporate Identity) of hotel I and realizing a positive service. Also this study associated with the company would help the design development of corporate uniform.

• Journal of the Korean Operations Research and Management Science Society
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• v.26 no.4
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• pp.83-97
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• 2001

Net Present Value (NPV) criterion has been the most widely used criterion to evaluate investment opportunities. However, the analysis based on the NPV criterion falls to consider the managerial flexibility of deferring decisions until major uncertainty is resolved. Recently, real options method attracted a lot of attention as a Powerful approach to address the problem. If investment decision is deferred, the value of the investment opportunity increases but opportunity cost increases at the same time. Therefore, it is important to decide the optimal timing how long the decision can be deferred. In this paper, we developed a model deciding the optimal decision timing. Using the real options approach, the model derived the optimal deferring time until a decision is made. Then, the model was applied to a Korean mobile telecommunications company who wants to invest on the wireless resale business. We believe that this model would be very useful to overcome the problem of NPV decision criterion. With this approach, we can make contingent decisions based on the observation of uncertainly resolutions.