• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.3
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• pp.9-18
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• 1998

For constructionof the next generation satellite B-ISDN/ATM networks considering integration with terrestrial information infrastructure networks, various high speed and wideband satellites with be launched and they will make used of frequency reue techniques for efficient management of limited frequency resource. Therefore, CCI(Co-Channel Interference) inherent in frequency reuse will be a dominant factor in performance degradation of satellite networks. This paper alanyzes the ATM cell transmission performance degradation caused by CCI. The satellite link, including up-link and down-link thermal noise, CCI, and nonlinear satellite transponder, is modeled and interleaving technique is used for compensating the ATM cell transmission performance degradation caused by burst error of satellite link. First, each satellite link subsystem is analyzed in detail and then end-to-end ATM cell transmission performance is evaluated with BER and CLR. Specifically, ATMcell transmission performance degradation caused by CCI is evaluated in detail.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.363-366
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• 2007

This paper evaluated the performance of circuit for compensate the frequency offset in OFDM using Simulink and designed a System Generator model for FPGA implementation. System Generator Model generated HDL code and RTL schematic. Also, evaluate the performance through Hardware Co-simulation, and investigated the result of timing analysis and resource estimation.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.14 no.1
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• pp.15-22
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• 2008

The excitement over radio frequency identification (RFID) technology has gained momentum in the last five years, with a diversification in the range of applications. Besides academic research into radio frequency identification (RFID) has proliferated over the last few years, however there is much to be desired on Packaging industry. In this paper, we present a literature reviews of researches of RFID system on Packaging, especially focused on RFID system standardization into packaging. There is not any packaging standard or guidance about tag locations, classification with the materials and so on. Therefore it hampers reduction of the distribution costs on political and corporate sides, and lack consistency of applying RFID system. The main focus of this review paper is to establish a constituency about legislating RFID system standard on packaging. It is hoped that the review will be a good resource for future research in order to applly RFID system to Packaging industry effectively.

• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.1
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• pp.93-98
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• 2020

Research on underwater sensor networks is increasing due to such reasons as marine resource management, maritime disaster prediction and military protection. Many underwater sensor networks performs wireless communication using an acoustic sound wave band signal having a relatively low frequency. So the digital part of their modem can take charge of carrier band signal processing. To enable this, the sampling rate of the baseband band signal should be increased to a sampling rate at which carrier band signal processing is possible. In this paper, we designed a sampling rate increasing circuit based on a CIC interpolator for underwater sensor nodes. The CIC interpolator has a simple circuit structure. However, since the CIC interpolator has a large attenuation of the pass band and a wide transition band, an inverse sinc LPF is added to compensate for frequency response of the CIC interpolator. The proposed interpolator was verified in time domain and frequency domain using ModelSim and Matlab.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.11
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• pp.1601-1606
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• 2011

32 sows (Landrace${\times}$Yorkshire) and their litters were used to evaluate the effects of varying creep feed duration on pre-weaning, post-weaning performance of piglets and sows. Sows were randomly assigned with 1, 2 or 3+ parities into 1 of 4 treatments. Creep feeding was initiated at day 5, 10 and 15 from birth for treatment 1 (TRT1), 2 (TRT2) and (TRT3), respectively, with a control group provided no creep feed. In this study, TRT1 and TRT2 diets had reduced (p<0.05) the post-weaning diarrhea scores in piglets and the weaning-to-estrus interval and cortisol concentration in sows at weaning time compared with other treatments. Dietary TRT1 led to a higher (p<0.05) epinephrine and norepinephrine concentrations than other treatments. No differences (p>0.05) were noted in suckling, sleeping, fighting frequency and mortality in piglet and eating, standing times, backfat and body weight loss in sows. In conclusion, creep feed initiated from day 5 and 10 reduce diarrhea scores in piglets and benefit the estrus interval in sows compared with those initiated from day 15 and no-creep feeding diets, indicating creep feeding could improve the pigs and sows performance, especially those initiated from day 5 and 10.

• Journal of the Korean Chemical Society
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• v.60 no.5
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• pp.327-341
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• 2016

This study explores the effective visual resources in the “regularity in chemical reactions” unit of ninth grade science textbooks (2009 revised version). The frequency and role of visual resources were initially examined, and the students’ perceptions of visual resources were investigated. The results of the analysis represented the learning material presentation (68%), motivational categories (14%), guide to inquiry procedures (9%), and inquiry results and summaries (8%). According to the investigation of the students’ perceptions of visual resources, the most effective visual resource for motivation is a photograph depicting physical and chemical changes, such as in bread baking and the most effective for learning material presentations in mass conservation, definite proportion, and stoichiometric concept units were a cartoon, graph, and formula representing stoichiometric phenomena, respectively. The most effective resource for guide to inquiry (experimental) procedures were photographs of both instruments and sequential experiment processes; and in the inquiry results and summary category, incomplete tables and graphs for students to work on themselves. The aims of this research are to increase the usefulness of visual resources in the teaching-learning activity and provide informative supplements for the development and improvement of visual resources, according to the students’ perceptions.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.10
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• pp.4738-4758
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• 2017

Resource allocation plays a crucial role in multiuser multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM) systems to improve overall system performance. While previously proposed resource allocation algorithms are mainly designed from the point of view of the information-theoretic, we formulate the resource allocation problem as an average bit error rate (BER) minimization problem subject to a total power constraint when considering employing realistic MIMO detection techniques. Subsequently, we derive the optimal subcarrier and power allocation algorithms for three types of well-known MIMO detectors, including the maximum likelihood (ML) detector, linear detectors, and successive interference cancellation (SIC) detectors. To reduce the complexity, we also propose a two-step suboptimal algorithm that separates subcarrier and power allocation for each detector. We also analyze the diversity gain of the proposed suboptimal algorithms for various MIMO detectors. Simulation results confirm that the proposed suboptimal algorithm for each detector can achieve a comparable performance with the optimal allocation with a much lower complexity. Moreover, it is shown that the suboptimal algorithms perform better than the conventional algorithms that are known in the literature.

• Journal of Family Resource Management and Policy Review
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• v.18 no.3
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• pp.61-77
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• 2014

Purpose of this study is to draw policy implications for family resource management's strategies and leisure culture revitalization to Korean baby-boomers. This study review leisure activities characteristics of Korean baby-boomers and find their characteristics' impact on leisure economy. This research analyzed with raw data of "National Research Leisure Activities 2012" in different methods: analysis of frequency, multiple regression analysis, Correspondence Analysis, and etc. As a result, compared to all age groups in Korea, Korean baby-boomers current participation in leisure activities is low, but their expense on leisure is high. Their leisure activities are varied from different genders to their incomes. Especially, baby-boomers, who are on high income, participate in wasteful leisure activities and their consuming behavior will be the mainstream of Korean leisure economy, so economy, which is aiming for baby-boomers, will be invigorated when the economy is more concerned with use values toward time. Particularly, preparing for the retirement of baby-boomers, further researches based on integrated family policy should be considered plans and efforts on encouraging active volunteer works and participation in leisure culture revitalization of Korean baby-boomers.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.12
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• pp.5943-5962
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• 2017

A resource allocation algorithm based on simultaneous wireless information and power transfer (SWIPT) to maximize the system throughput is proposed in orthogonal frequency division multiplexing (OFDM) relay networks. The algorithm formulates the problem under the peak power constraints of the source and each subcarrier (SC), and the energy causality constraint of the relay. With the given SC allocation of the source, we give and prove the optimal propositions of the formulated problem. Then, the formulated problem could be decomposed into two separate throughput maximization sub-problems by setting the total power to transfer energy. Finally, several SC allocation schemes are proposed, which are energy priority scheme, information priority scheme, balanced allocation scheme and exhaustive scheme. The simulation results reveal that the energy priority scheme can significantly reduce computational complexity and achieve approximate performance with the exhaustive scheme.

• Journal of the Korean Solar Energy Society
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• v.40 no.4
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• pp.1-11
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• 2020

The Journal of the Korean Solar Energy Society is the first journal in South Korea that adopts wind energy as one of its subjects. Since 2000, more than 140 papers on wind energy have been published in the journal, which accounts for 8.5% of the total publication. However, in recent years, the number of published papers on wind energy has been decreasing steadily, and a reason for this decline is the significant dependence on a few specific institutions and authors. In this study, wind energy subjects were classified using the frequency analysis of the subject words extracted from the title, keywords, and abstract of wind energy papers using the text mining technique. In addition, the Korea Citation Index was used to perform quantitative level evaluation by subject and institution and to analyze the trends and characteristics of the wind energy field. Therefore, it was identified that in terms of the number of publications and citations, the main subject areas were resource/micrositing and policy/potential.