• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.207-210
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• 2009

According to the recent demand for materials for use in various displays and solid state lightings, new phosphors with improved performance have been pursued consistently. Multi objective genetic algorithm assisted combinatorial material search (MOGACMS) strategies have been applied to various multi-compositional inorganic systems to search for new phosphors and to optimize the properties of phosphors.

• 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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.12
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• pp.1675-1681
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• 2017

As recently the demand on electric power has been increasing, the requirement of power supply reliability has been increased. Accordingly, the number of HVDC transmission systems in the world has been steadily increased, which have been installed in the power system to transmit a large capacity power to the long distant and interconnect the power grid between different countries. etc. #1 HVDC Transmission System was installed between Haenam and Jeju island in 1998, which is the first HVDC system furnished in korea. and has been operated until now. Before #1 HVDC Transmission System being installed, the power system of the Jeju Island is a isolated power system from that of Korea mainland. After the construction of #1 HVDC the system has made the Jeju power system more reliable and also been able to supply the mainland power, which was cheaper than that of Jeju island, to Jeju island. The construction of additional HVDC transmission system between mainland and the Jeju Island has been currently underway to cope with recent changes of the power market of the Jeju island, for examples the increase of power demand and the capacity of wind power generation. etc. #2 HVDC Transmission System construction was completed in 2012. #3 HVDC Transmission System will be also installed according to the plan. If all goes as planned, the Jeju power system will be operated with Multi-Infeed HVDC system connected to mainland power system. So the additional studies are needed in order to maintain the stability of the Jeju power system and get the efficiency of the Multi-Infeed HVDC system. Therefore, in this paper, the optimal operation strategies of the Multi-Infeed HVDC system between the mainland of Korea and the Jeju are suggested to ensure the stability of the power system in Jeju Island when the Multi-Infeed HVDC system is operated between two power system.

• Journal of Information Technology Applications and Management
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• v.17 no.3
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• pp.135-150
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• 2010

Interactivity has been referred to as an important element promoting students' active participation in virtual classes. Assuming that interactivity cannot be defined by a single dimension, this study proposes multi-dimensional interactivity. Multi-dimensional interactivity includes all types of interactivity in e-learning. This study explored multi-dimensional interactivity which affects learners' satisfaction with e-learning. Data were collected from 132 students who had attended e-learning courses and the relationship between multi-dimensional interactivity and learners' satisfaction levels were tested through regression analysis. The result of this study showed that mechanical, reactive, and creative interactivity were positively related to learners' satisfaction. However, social interactivity seemed not to be related to learners' satisfaction. This study provides new insights on interactivity and verifies the importance of the multi-dimensional interactivity. The result of this study is expected to provide practical implications for interactivity strategies in e-learning.

• Research in Community and Public Health Nursing
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• v.31 no.3
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• pp.256-268
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• 2020

Purpose: This study aimed to explore ecological factors and strategies for childhood obesity prevention targeting vulnerable children using a community-based participatory research (CBPR) methodology. Methods: The CBPR was conducted by following basic process steps. Participants were 12 community stakeholders such as community child center directors (n=4), vulnerable children's mothers (n=3), community health center officials (n=2), and lay health advisors (n=4); they were purposively sampled from K municipal county in Seoul, South Korea. The qualitative content analysis was performed to explore main themes of the ecological factors and strategies by using data obtained from 5 times of focus group interview. Results: Twelve ecological factors associated with childhood obesity prevention were identified: Intrapersonal factors including emotional overeating; interpersonal factors including permissive parenting style of children's eating behaviors; organizational factors including social workers' less educational opportunities; and community/policy factors including less government financial support. Four ecological strategies for childhood obesity prevention were addressed: Developing obesity prevention programs targeting vulnerable children' lifestyles; promoting parents' active participation in education; building healthy meal service environments through empowering social workers; and building supportive community environment and securing community resources for child obesity prevention. Conclusion: Our findings may be informative in terms of providing a comprehensive understanding of multi-level ecological barriers against vulnerable children' obesity prevention and, moreover, guiding multi-level strategies for preventing childhood obesity targeting children enrolled in community child centers.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.4
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• pp.303-317
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• 2013

Two novel clocking strategies for a high-speed multi-channel serializer-deserializer (SERDES) are proposed in this paper. Both of the clocking strategies are based on groups, which facilitate flexibility and expansibility of the SERDES. One clocking strategy is applicable to moderate parallel I/O cases, such as high density, short distance, consistent media, high temperature variation, which is used for the serializer array. Each group within the strategy consists of a full-rate phase-locked loop (PLL), a full-rate delay-locked loop (DLL), and two fixed phase alignment (FPA) techniques. The other is applicable to more awful I/O cases such as higher speed, longer distance, inconsistent media, serious crosstalk, which is used for the deserializer array. Each group within the strategy is composed of a PLL and two DLLs. Moreover, a half-rate version is chosen to realize the desired function of 1:2 deserializer. Based on the proposed clocking strategies, two representative ICs for each group of SERDES are designed and fabricated in a standard $0.18{\mu}m$ CMOS technology. Measurement results indicate that the two SERDES ICs can work properly accompanied with their corresponding clocking strategies.

• Korean Journal of Health Education and Promotion
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• v.33 no.4
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• pp.89-100
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• 2016

Objectives: Life style modification leads to decrease health risk and change of health status for person at health risk. This study aimed to suggest essential components and effective strategies for customized health management service to provide individual and risk group in public and private health care organizations. Methods: To systematic review the essential component of health management service, I performed to collect political legislation, research papers, reports, publication and public release for heath management service from 2008 to 2016. Essential components of heath management service were service scope, service design, organizations and applied technology. Results: Service cope was composed of health risk factors, such as smoking, drinking, nutrition, physical activity and weight control. Main strategies were customized health management services, personalized behavior modification programs, evidence-based service protocol, utilization of information and communications technology (ICT), multi-dimension and multi-level approach, and public and private organizations partnership through health policies and health care system. Conclusions: To make the most of the limited resources, it should require a systematic approach that focuses on continuous monitoring and partnership of health management service.

• Journal of the Korean Society of Clothing and Textiles
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• v.35 no.5
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• pp.587-600
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• 2011

This study presents the strategic directions for Korean multi-brand fashion stores by running in-depth industry research and market analysis. Over 20 professionals were selected from Korean multi-brand fashion stores for this study and in-depth interviews were conducted to evaluate related subjects. The results of the study were as follows. First, Korean multi-brand fashion stores could be classified into three criteria: operating ownership, merchandise mix, and store identity. Second, operating ownership criterion was chosen for further investigations of strategies and directions of the multi-brand fashion stores. The operating ownership criterion consists of three types; department store types, specialty store types, and boutique types. Each type deploys different buying practice, organizational strategies, and distribution channels. Lastly, the suggested strategic directions for each type are summarized as follows. The 'department store type' should utilize its strong direct buying capabilities and acquisition of merchandising can be more effectively managed. The store should utilize its strong buying power as a tool to develop new private brands (PBs). For 'specialty store type', two key factors have been derived: market share expansion and positioning themselves to become a new distribution channel. To respond to these factors, the store needs to be perceived as a brand then diversify its business. Strengthening its brand will allow it to expand into a new distribution channel and also enable a strategic partnership with its competitor brands. The factors influencing 'boutique type' is personalization and uniqueness. With an emphasis on the uniqueness of products and merchandising it will be able to implement the role as a personal shopper and stylist to provide a very personalized service to its customers.

• Journal of the Korea Society of Computer and Information
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• v.28 no.2
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• pp.201-207
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• 2023

In this paper, we propose an optimal model for mid to long-term price prediction of agricultural products using LGBM, MLP, LSTM, and GRU to compare and analyze the three strategies of the Multi-Step Time Series. The proposed model is designed to find the optimal combination between the models by selecting methods from various angles. Prior agricultural product price prediction studies have mainly adopted traditional econometric models such as ARIMA and LSTM-type models. In contrast, agricultural product price prediction studies related to Multi-Step Time Series were minimal. In this study, the experiment was conducted by dividing it into two periods according to the degree of volatility of agricultural product prices. As a result of the mid-to-long-term price prediction of three strategies, namely direct, hybrid, and multiple outputs, the hybrid approach showed relatively superior performance. This study academically and practically contributes to mid-to-long term daily price prediction by proposing an effective alternative.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.5
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• pp.467-473
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• 2013

Diverse approaches for reducing the total energy consumption of machine tools have been introduced and developed, to cope with rapid increase of total energy costs in world-wide manufacturing industries. To realize the improvement of the energy efficiency, systematic and integrated strategies must be considered, including energy-saving design, optimized control operation and concrete evaluation of the energy efficiency. This paper proposes key enabling technologies required to improve the energy efficiency of 5-axis multi-functional machining tools, considering both of system design and operation in the real production environments. Related standardized procedures of the energy efficiency evaluation is also represented.