• Journal of Communications and Networks
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• v.7 no.2
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• pp.144-156
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• 2005

Video streaming over wireless networks is challenging due to node mobility and high channel error rate. In this paper, we propose a multi-source video streaming (MUVIS) system to support high quality video streaming service over IEEE 802.1l-based wireless networks. We begin by collocating a streaming proxy with the wireless access point to help leverage both the media server and peers in the WLAN. By tracking the peer mobility patterns and performing content discovery among peers, we construct a multi-source sender group and stream video using a rate-distortion optimized scheme. We formulate such a multi-source streaming scenario as a combinatorial packet scheduling problem and introduce the concept of asynchronous clocks to decouple the problem into three steps. First, we decide the membership of the multisource sender group based on the mobility pattern tracking, available video content in each peer and the bandwidth each peer allocates to the multi-source streaming service. Then, we select one sender from the sender group in each optimization instance using asynchronous clocks. Finally, we apply the point-to-point rate-distortion optimization framework between the selected sender-receiver pair. In addition, we implement two different caching strategies, simple caching simple fetching (SCSF) and distortion minimized smart caching (DMSC), in the proxy to investigate the effect of caching on the streaming performance. To design more realistic simulation models, we use the empirical results from corporate wireless networks to generate node mobility. Simulation results show that our proposed multi-source streaming scheme has better performance than the traditional server-only streaming scheme and that proxy-based caching can potentially improve video streaming performance.

• Journal of Family Resource Management and Policy Review
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• v.20 no.3
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• pp.95-113
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• 2016

This study investigates the potential for multi-cultural youths, given their innate bilingual and dual culture, to be trained as the competent ODA professionals. For the purpose of collecting information, we organized two different kinds of FGI in 2015. The first FGI was conducted with a group of 10 expert participants from August 17 to September 25. The second FGI was conducted four times, from October 5 to October 23, with 13 adolescents from multi-cultural families from Russia, Mongolia, Vietnam, India, Indonesia, Japan, and China. The semi-structured interview items were passed through a formal review process of the Institutional Ethics Committee. Furthermore, with the participants' pre-consent to recording, all recorded data were categorized through the transcription process. The results are as follows. While the potential for nourishing bilingual and dual cultural capabilities are high for the adolescent children of multi-cultural families, the expert group also emphasized the negative aspects of these capabilities being suppressed due to the relatively oppressed family environment. The expert group therefore suggests the following: building parent awareness of ODA human resources, developing an educational career transition roadmap, and providing institutional incentives for ODA. In addition, to some extent, the researchers were able to detect some positive self-esteem among the adolescent children of multi-cultural families as a result of the bilingual and dual cultural competencies required to be ODA personnel. In sum, the research provides insight into the need for national social support for the adolescent children of multi-cultural families, so that their strengths are not extinguished, in order that they might grow up as competent ODA personnel.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.6-8
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• 2008

본 논문은 전력IT 분야에 새롭게 큰 관심이 집중되고 있는 Multi-Agent System 적용에 대하여 배전자동화 시스템에서의 적용방안을 제안하고 있다. IEEE Working Group에서 Power System에 적용되는 Multi-Agent에 대한 연구를 진행하였다. 이 내용을 기반으로 배 전자동화 시스템에서는 어떻게 Multi-Agent System이 적응되어야 하는지에 대한 방법을 제안하고 있다.

• Journal of Korean Clinical Nursing Research
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• v.17 no.2
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• pp.150-162
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• 2011

Purpose: Multi-drug resistant (MR) infections among intensive care unit (ICU) patients with oral intubation and a ventilator are serious nosocomial infections. This study was done to compare the effects of oral care and ventilator circuit on reduction of MR infections. Methods: A total of 92 participants were recruited from an ICU at C University Hospital in G-city, Korea, assigned to one of 4 groups and evaluated: group I received oral care with sponge and reusable circuit; group II received oral care with tooth brush and reusable circuit; group III received oral care with sponge and disposable circuit; group IV received oral care with tooth brush and disposable circuit. Results: Prevalence rate of MR infections was highest in group I (47.8%), followed by group II (30.4%), group IV (19.0%), and group III (13.6%). Of the four groups, group III showed a significantly decreased MR infections (p=.035) and higher possibility of survival rate as time passes according to survival analysis (p=.019). Conclusion: Results of this study indicate that using disposable ventilator circuit significantly decreases MR infections and raises the possibility of a higher survival rate as time passes. According to this study, the use of disposable ventilator circuit is useful in prevention of MR infections.

• Journal of the Korean Statistical Society
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• v.35 no.4
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• pp.343-353
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• 2006

The two-way balanced one-level rotation design, $r_1^m-r_2^{m-1}$, and the three-way balanced multi-level rotation design, $r_1^m(\iota)-r_1^{m-1}$, were discussed (Park et al., 2001, 2003). Although these rotation designs enjoy balancing properties, they have a restriction of $r_2=c{\cdot}r_1$ (c should be a integer value) which interferes with applying these designs freely to various situations. To overcome this difficulty, we extend the $r_1^m(\iota)-r_1^{m-1}$ design to new one under the most general rotation system. The new multi-level rotation design also satisfies tree-way balancing which is done on interview time, rotation group and recall time. We present the rule and rotation algorithm which guarantee the three-way balancing. In particular, we specify the necessary condition for the extended three-way balanced multi-level rotation sampling design.

• Journal of Family Resource Management and Policy Review
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• v.19 no.3
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• pp.1-16
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• 2015

The purpose of this study was to synthesize the results of studies on the effects of multi-cultural education program for Korean children. Using the author's own selection criteria, 17 studies were finally selected and 31 effect sizes were calculated from these studies and used for meta analysis. The overall effect size for all studies on the random effect model was .802, and it was positive and high. Given the heterogeneity among the effect size, subgroup analysis was conducted. According to the analysis, effect sizes significantly differed depending on program goal, concerned multi-cultural higher than others. Result also showed that the high scored effect sizes were the general family, pre-school age children group, and the program were 11-20 children group in size, and 11~20 times in frequency of education.

• Journal of the Korean Ceramic Society
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• v.40 no.9
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• pp.832-836
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• 2003

Multi-layer ceramic composites were prepared by tape casting followed by hot pressing using silicon nitride layer with silicon nitride whiskers, silicon nitride layer with silicon carbide particles and boron nitride-alumina layer. The whiskers were aligned during the casting. As the whisker content of the silicon nitride layer was increased up to 10 wt％, the flexural strength of the multi-layer composite was increased. However, further increase of the whisker content in the layer resulted in a rapid decrease of the strength of the composite. The results suggest that the strength of multi-layer ceramic composite showing non-catastrophic failure behavior can be significantly improved by incorporating the aligned whiskers in the layers.

• Structural Engineering and Mechanics
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• v.45 no.2
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• pp.211-232
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• 2013

In this study a multi-objective optimization problem is solved. The objectives used here include simultaneous minimum construction cost in term of sections weight, minimum structural damage using a damage index, and minimum non-structural damage in term of inter-story drift under the applied ground motions. A high-speed and low-error neural network is trained and employed in the process of optimization to estimate the results of non-linear time history analysis. This approach can be utilized for all steel or concrete frame structures. In this study, the optimal design of a planar eccentric braced steel frame is performed with great detail, using the presented multi-objective algorithm with a discrete population and then a moment resisting frame is solved as a supplementary example.

• Nuclear Engineering and Technology
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• v.52 no.2
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• pp.223-229
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• 2020

The present work proposes a solution to the static Boltzmann transport equation approximated by the simplified P₃ (SP₃) on angular, and the analytic coarse mesh finite difference (ACMFD) for spatial variables. Multi-group SP₃-ACMFD equations in 3D rectangular geometry are solved using the GMRES solution technique. As the core time dependent analysis necessitates the solution of an eigenvalue problem for an initial condition, this work is hence devoted to development and verification of the proposed static SP₃-ACMFD solver. A 3D multi-group static diffusion solver is also developed as a byproduct of this work to assess the improvement achieved using the SP₃ technique. Static results are then compared against transport benchmarks to assess the proximity of SP₃-ACMFD solutions to their full transport peers. Results prove that the approach can be considered as an acceptable interim approximation with outputs superior to the diffusion method, close to the transport results, and with the computational costs less than the full transport approach. The work would be further generalized to time dependent solutions in Part II.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.359-362
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• 2006

This study develops an automatic berthing control algorithm for ships with a bow thruster and a stern thruster as well as a rudder. A nonlinear mathematical model for low speed maneuvering of ships is used to develop a MIMO(multi-input multi-output) nonlinear control algorithm. The algorithm consists of two parts, which are forward velocity control and heading angle control. The control algorithm is designed based on the longitudinal and yaw dynamic models of ships. The desired heading angle is obtained by the so called "Line of Sight" method. An optimal control force allocation method of the rudder and the thrusters is suggested. The nonlinear control algorithms are tested by numerical simulations using MATLAB, and shows good tracking performances.