• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.561-564
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• 2006

Because of new requirements related to the employment of SMT(Surface Mounting Technology) manufacturing and the diversity of components on high density PCB(printed circuit boards), Thermal control of the reflow process is required in oder to achieve acceptable yields and reliability of SMT assemblies. Accurate control of the temperature distribution during the reflow process is one of the major requirements, especially in lead-free assembly. This study has been performed for reflow process using the commercial CFD tool(Fluent) for predicting flow and temperature distributions. There was flow recirculation region that had a weak point in the temperature uniformity. Porous plate was installed to prevent and minimize flow recirculation region for acquiring uniform temperature in oven. This paper provided design concept from CFD results of the steady state temperature distribution and flow field inside a reflow oven.

• IEMEK Journal of Embedded Systems and Applications
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• v.2 no.4
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• pp.242-250
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• 2007

Wireless sensor networks are subject to highly heterogeneous system requirements in terms of their functionality and performance due to their broad application areas. Though the heterogeneity hinders the opportunity of developing a single universal platform for sensor networks, efforts to provide uniform, inter-operable and scalable ones for sensor networks are still essential for the growth of the industry as well as their technological advance. As a part of our work to develop such a robust platform, this paper presents the software architecture for sensor nodes with focus on our sensor node operating system and its configuration methodology. Addressing principle issues in its design space which includes programming, execution, task scheduling and software layer models, our architecture is highly reconfigurable with respect to system resources and functional requirements and also highly efficient in supporting multi-threading under small system resources.

• Journal of Aerospace System Engineering
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• v.3 no.1
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• pp.17-22
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• 2009

For establishing new certification requirements for aircraft engines, Technical background of FAR Part33 amendments has reviewed and studied in this paper. The FAA is amending type certification standards for aircraft engines. These changes reflect current industry practices and harmonize FAA standards with those recently adopted by the European Aviation Safety Agency (EASA). These changes establish uniform standards for all engine control systems for aircraft engines certificated by both U.S. and European countries and will simplify airworthiness approvals for import and export.

• Structural Engineering and Mechanics
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• v.24 no.2
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• pp.155-180
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• 2006

Many applications in mechanical design involve elastic bodies coming into contact under the action of the applied load. The distribution of the contact pressure throughout the contact interface plays an important role in the performance of the contact system. In many applications, it is desirable to minimize the maximum contact pressure or to have an approximately uniform contact pressure distribution. Such requirements can be attained through a proper design of the initial surfaces of the contacting bodies. This problem involves a combination of two disciplines, contact mechanics and shape optimization. Therefore, the objective of the present paper is to develop an integrated procedure capable of evaluating the optimal shape of contacting bodies. The adaptive incremental convex programming method is adopted to solve the contact problem, while the augmented Lagrange multiplier method is used to control the shape optimization procedure. Further, to accommodate the manufacturing requirements, surface parameterization is considered. The proposed procedure is applied to a couple of problems, with different geometry and boundary conditions, to demonstrate the efficiency and versatility of the proposed procedure.

• Journal of Korean Institute of Industrial Engineers
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• v.15 no.2
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• pp.11-22
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• 1989

The problem of scheduling n-jobs on m-uniform parallel machines is considered, in which each job has a release time, a deadline, and a processing requirement. The job processing requirements are allocated to the machines so that the maximum of the load differences between time periods is minimized. Based on Federgruen's maximum flow network model to find a feasible schedule, a polynomially bounded algorithm is developed. An example to show the effectiveness of our algorithm is presented.

• Journal of the Korean Mathematical Society
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• v.56 no.5
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• pp.1247-1263
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• 2019

In ordered trees, two randomly chosen vertices are said to be dependent if one lies under the other. If not, we say that they are independent. We consider several classes of ordered trees with uniform updegree requirements and find the generating functions for the trees with two marked dependent/independent vertices. As a result, we compute the probability for two vertices being dependent/independent. We also count such trees by the distance between two independent vertices.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.13
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• pp.657-677
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• 2000

Since January 1, 1999, traders, bankers and their counsels worldwide have available for their use the first set of rules exclusively dealing with standby letters of credit:the International Standby Practices(ISP98). Numerous standbys have alreadby been issued in the United States and worldwide subject to the new ISP. The international banking community is anticipating an increasing demand from their customers to issue ISP-governed undertakings. Before the adoption of ISP, traders and bankers had only the choice of issuing their standby subject to the International Chamber of Commerce's(ICC) Uniform Customs and Practices for Documentary Credits(UCP) and, to a much lesser extent, to the ICC's Uniform Rules for Demand Guarantees(URDG). However, practice showed that UCP rules are not easily adapted to regulate transnational standbys. Indeed, UCP was conceived to govern documentary credits, which are intended to serve as a means of payment. By contrast, standbys are means of guaranty. The core of UCP cannot therefore be appropriate for standby practices and, as a consequence, a number of UCP's provisions have to be excluded in the standby's text. UCP's shortcomings indicated above fulfil the requirements of a key factor for the success of uniform rules. Indeed, to achieve success in the sense of meeting the market's acceptance, any such rules should fill a widely recognized need expressed by merchant community to which such rules are addressed. The ISP cleary has such a vocation. Nonetheless, the already largely encumbered regulatory environment of guarantee devices can hardly go unnoticed. The question therefore arises as to the proper place of ISP in such a context.

• Journal of the Korean Home Economics Association
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• v.50 no.5
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• pp.51-65
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• 2012

The purpose of this study is to provide empirical basic data to develop public uniforms design, by understanding international universality and advanced design sense, through the analysis of public uniforms design at home and abroad. The theoretical study reviewed the character and area of public design, and the concepts and requirements of public uniforms. The empirical study analyzed public uniform design at home and abroad, focusing on typical public uniforms, such as police, fire fighter, and street cleaner. The results of this study were as follows. First, the police uniform has a standardized and formal suit style, which consists of a single-breasted dk-PB jacket with a notched collar and pants. It uses PB as the main color, to show their authority and role reliability. Epaulet or badge, which represents belonging and difference in rank, are attached to express the identity of an organization. Second, the fire fighter uniform consists of a hip length coat with a stand collar effective for heat shielding, and straight pants with flap pockets, in which it is easy to put things. Its main color is dkg-PB, to mitigate visual fatigue and enhance comfort, and an accent color scheme is used, to effectively raise visual attention and safety. Finally, the street cleaner uniform has a casual style, which consists of a jumper with a shirt collar and pants for high activity. v-YR and R with high chroma is mainly used, for increased attention during day and night work, to stress safety.

• Journal of Fashion Business
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• v.17 no.2
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• pp.82-94
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• 2013

This study aims to investigate purchase attitude towards uniforms, wear condition and their requirements for functional school uniforms for high school boy students, and to help to present basic data for the development of functional school uniforms by reflecting requirements from high school students. First, research on school uniform brands purchased in Busan, Ulsan, and Kyungnam regions showed 2 brands were preferred, and the school uniform purchase expenses are primarily between two hundred thousand won and three hundred thousand won. Second, in terms of differences among fabrics of summer and winter uniforms, many students answered that 'they are similar' or 'there is no difference'. As for complaints about winter uniforms, thermal insulation accounts for the highest rate. As a result of research on underwear worn primarily in the winter, boy students tend to wear underwear to keep their lower bodies warm rather than their upper bodies. They tend to keep their upper bodies warm with outerwear such as vests, cardigans, and padding jumper. According to a survey on experience and satisfaction of functional uniforms, students showed satisfaction with more than three points to all questions except for two, which means their satisfaction about the functions of uniforms that they wear currently is above the average. Third, many boy students complains about the thermokeeping of winter uniforms, especially thigh parts of pants. It is required to make research for the improvement of functional pants for boy students.

• Animal Bioscience
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• v.36 no.4
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• pp.601-608
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• 2023

Objective: This study was conducted to investigate the effects of energy and protein levels in the diet of Hanwoo heifers on growth response and animal behavior. Methods: Forty heifers were randomly allocated into three experimental groups according to the target daily weight gain in 8 pens (T-0.2, 2 replications; T-0.4 and -0.6, 3 replications) based on similar body weight (BW) and age in months. The target average daily gain (ADG) was set at 0.2 (T-0.2), 0.4 (T-0.4), and 0.6 kg/d (T-0.6), and feed was based on National Institute of Animal Science (NIAS, 2017). In order to minimize hunger stress of T-0.2 and -0.4, the feeding ratio of rice straw was set to 55%, 50%, and 45% for T-0.2, -0.4 and T-0.6, respectively, so that the dry matter (DM) intake for all treatment groups was uniform but the energy and protein levels in the diet were adjusted differently. A total of 6 items (lying, standing, eating, rumination, walking and drinking) of animal behavior were analyzed. Results: During the whole period of the experiment, the ADG of the T-0.2, -0.4 and -0.6 treatments were 0.48, 0.56, and 0.65 kg/d (p<0.05), respectively, showing higher gain than the predicted value, especially for the low target ADG group. Based on these results, regression equations for the total digestible nutrient (TDN) and crude protein (CP) requirements were derived. No behavioral differences were found according to the energy and protein levels in the diet because the DM intake was kept constant by adjusting the roughage and concentration ratio. However, eating time was longer (p<0.05) at T-0.2 than T-0.6 during the whole day. Conclusion: Through this study, it was possible to derive regression equations for predicting TDN and CP requirements according to the target ADG and BW.