• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.9
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• pp.16-23
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• 2009

In this paper, we propose a new distributed Alamouti space-time block coding scheme using cooperative relay system composed of one source node, three relay nodes and one destination node. The source node is assumed to be equipped with two antennas which respectively use a 2-beam array to communicate with two nodes selected from the three relay nodes. During the first time slot, the two signals which respectively were transmitted by one antenna at the source, are selected by one relay node, added, amplified, and forwarded to the destination. During the second time slot, the other two relay nodes implement the conjugate and minusconjugate operations to the two received signals, respectively, each in turn is amplified and forwarded to the destination node. This transmission scheme represents a new distributed Alamouti space-time block code that can be constructed at the relay-destination channel. Through an equivalent matrix expression of symbols, we analyze the performance of this proposed space-time block code in terms of the chernoff upper bound pairwise error probability (PEP). In addition, we evaluate the effect of the coefficient $\alpha$ ($0{\leq}{\alpha}{\leq}1$) determined by power allocation between the two antennas at the source on the received signal performance. Through computer simulation, we show that the received signals at the three relays have same variance only when the value of $\alpha$ is equal to $\frac{2}{3}$, as a consequence, a better performance is obtained at the destination. These analysis results show that the proposed scheme outperforms conventional proposed schemes in terms of diversity gain, PEP and the complexity of relay nodes.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.4 s.22
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• pp.85-93
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• 2002

Since the National Geographic Information System(NGIS) project of 1995, the geographic information projects have been promoted in various areas such as central and local governments. In the fact that large scale budget has been invested to geographic information projects as a national policy, the cost-benefit analysis would be essential to enhance the efficiency of the resource allocation. In this circumstance, this study analyzes the costs and benefits of geographic information produced by NGI(National Geography Institute). As a result of the cost-benefit analysis, the total amount of benefits were estimated approximately 620 million dollars and the accumulated ratio of the cost to benefit was 1 to 4.4. Also, the internal ratio of the benefit was 38%, which justified the large scale investment. In case of adding qualitative benefits which can not be measured in a quantitative term, the overall benefits from using such geographic information would be much higher than quantitative benefits. Further research work is required for more objective verification of the large scale national project such as building nationwide geographic information.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.10
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• pp.1-9
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• 2001

The MAC (Medium Access Control) protocol is needed for the OLT(Optical Line Termination) to allocate bandwidth to ONUs(Optical Network Units) and ONTs(Optical Network Terminations) dynamically in the ATM PON(Passive Optical Network). With the protocol, the OLT gathers ONUs' informations and provides grants efficiently to each ONU. Two important functions of the MAC protocol is the grant request procedure and the grant distribution algrithm. The latter has the greatest arithmetic portion in the TC(Transmission Convergence) module, occupies a relatively large portion of the overall chip area, has often been the limiting factor in terms of speed, and should be designed to guarantee the quality of service for various traffics. In this paper, we implement the MAC with the FPGA which can allocate grants dynamically according to the queue length information and the number of active ONUs and distribute grants uniformly to minimize the cell delay variation for each ONU. The structure of the MAC scheduler for the dynamic bandwidth assignment has a programmable look-up table. Also, it has a simple structure, the less chip area, and the lower delay time.

• Journal of the Korea Society of Computer and Information
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• v.10 no.2 s.34
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• pp.205-213
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• 2005

A balanced regional development has a great meaning of economics in the fact that the People could enjoy the equal level of lift everywhere in the country by reducing the income disparity and economic productivity between regions, however as the our country was given Preponderance of economical power and development to the metropolitan area centering around Seoul due to a factor of politics, social structure as well as a national economic policy centering around a rapid economic growth, the unbalanced regional growth gave rise to great hindrance to a national development. Especially, the unbalanced 9rowth between regions gave rise to a sense of alienation to a citizen in a special region as well as a distortion of an effective resources distribution. therefore it was deepen a social discord to hinder the unity of the people due to always coming to involve social ,political affairs. The major contents of this study is to clarify relations between the economic growth and the balanced regional development to form a concept of a national development, and this thesis made disparities in population and convenient facilities between regions through change of convenient facilities of life, economic growth, and population between regions an analytic object to concrete the studies. Also, this thesis made a whole countw land an analytic object of spatial sphere. and it made a unit of ten years when the five-year economic development plan was achieved from the year 1962 to 2001 an otject of the time range of studies.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.3
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• pp.237-244
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• 1994

To elucidate the physiological characteristics of 2 japonica type and 2 tongil type of rice cultivars, photosynthesis, respiration and diurnal changes of photosynthesis rate had been investigated 6 times at each growing stage. The ratios of photosynthetic part of tongil types were higher than those of japonica types at tillering stage. The highest photosynthetic activity was measured on August 1, before heading in each growing stage, and efficiency of photosynthesis showed its the highest on July 25. Diurnal photosynthetic curve at heading stage reached the peak at 11-12 AM, but after 2 weeks from heading stage, the peak apperred at 1-2 PM. Conversion of respiration into photosynthesis for $CO_2$ fixation started 30~60 minutes later than the standard sunrise time and reconversion for carborhdrate accmulation began 50~60 minutes earlier than the standard sunset time. Photosynthesis showed positive correlation with chlorophyll content and root activity. Harvest index of tongil type cultivars were significantly higher than those of japonica type cultivars.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.3
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• pp.14-28
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• 2010

The aim of this study is to investigate crime hotspot areas using the spatio-temporal cluster analysis which is possible to search simultaneously time range as well as space range as an alternative method of existing hotspot analysis only identifying crime occurrence distribution patterns in urban area. As for research method, first, crime data were collected from criminal registers provided by official police authority in M city, Gyeongnam and crime occurrence patterns were drafted on a map by using Geographic Information Systems(GIS). Second, by utilizing Ripley K-function and Space-Time Scan Statistics analysis, the spatio-temporal distribution of crime was examined. The results showed that the risk of crime was significantly clustered at relatively few places and the spatio-temporal clustered areas of crime were different from those predicted by existing spatial hotspot analysis such as kernel density analysis and k-means clustering analysis. Finally, it is expected that the results of this study can be not only utilized as a valuable reference data for establishing urban planning and crime prevention through environmental design(CPTED), but also made available for the allocation of police resources and the improvement of public security services.

• Journal of the Korean Society for Library and Information Science
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• v.43 no.2
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• pp.5-28
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• 2009

The purpose of this study is to investigate the use of the electronic information resources of humanities scholars in Korea and propose the planning of academic library and information services to serve their needs. To collect data, a postal survey was conducted during the period of November 2007 through January 2008. Out of 799 humanities scholars sampled from 25 universities, 132 responded with a completion rate of 16%. The major findings of this study are as follows: Firstly, the majority of humanities scholars distribute their time equally between research and education, and conduct independent research. Secondly, they use, to a certain degree, electronic information resources largely in text format, and depend upon the electronic collection of their academic libraries. Thirdly, with the exception of a couple of sources of electronic journal resources, the electronic resources that these humanities scholars regularly use vary so widely that none could be considered to be a common resource. Fourthly, they value the convenience of accessing and using electronic resources, but worry about the quality and scope of the contents. It is suggested that academic libraries (1) become the gateway for the electronic information that is available both inside and outside the library, (2) provide integrated search feature for and a 'single sign on' access to electronic resources, and (3) plan customized user education for specific subject fields in the humanities.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.6
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• pp.187-193
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• 2015

The ICT healing platform sets a couple of goals including preventing chronic diseases and sending out early disease warnings based on personal information such as bio-signals and life habits. The 2-step open system(TOS) had a relay designed between the healing platform and the storage of personal health data. It also took into account a publish/subscribe(pub/sub) service based on large-scale connections to transmit(monitor) the data processing process in real time. In the early design of TOS pub/sub, however, the same buffers were allocated regardless of connection idling and type of message in order to encode connection messages into a deflate algorithm. Proposed in this study, the dynamic buffer allocation was performed as follows: the message transmission type of each connection was first put to queuing; each queue was extracted for its feature, computed, and converted into vector through tf-idf, then being entered into a k-means cluster and forming a cluster; connections categorized under a certain cluster would re-allocate the resources according to the resource table of the cluster; the centroid of each cluster would select a queuing pattern to represent the cluster in advance and present it as a resource reference table(encoding efficiency by the buffer sizes); and the proposed design would perform trade-off between the calculation resources and the network bandwidth for cluster and feature calculations to efficiently allocate the encoding buffer resources of TOS to the network connections, thus contributing to the increased tps(number of real-time data processing and monitoring connections per unit hour) of TOS.

• Journal of Environmental Policy
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• v.8 no.4
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• pp.95-124
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• 2009

This study aims to introduce greenhouse gas emission trading in Korea as a highly cost-effective mechanism for controlling emissions. The Basic Act on Low-Carbon Green Growth will cover methods of emissions allocation, national inventory, and trading systems (i.e. emissions trading platforms, national registry,and clearing and settlement platforms). The Korean emission scheme will be based on the Korean Climate Change Act proposed by the National Assembly and Government with a cap-and-trade scheme. The national allowances will be allocated by the hybrid system. To establish the national inventory, TRADEMARKS (Telemetering System) and emissions factors are effective for greenhouse gas emissions measurement. It will likewise be effective for the national registry to be implemented via a Korean Integrated Registry, the emissions trading platform via the KRX (Korean Exchange), and the clearing and settlement platform via the KSD (Korean Securities Depository). In other words, the KRX will manage product development and marketing for Korean Carbon Financial Instruments (including commodities, futures, and options contracts) listed and admitted to trading on the KRX. All emissions trades will be standardized and cleared by the KSD.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.2
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• pp.244-252
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• 2006

The aims of this study were to determine if flowable composites can be used as pit and fissure sealants without bonding agents. Three flowable composites(Filtek Flow, Tetric Flow, Charmfil Flow) and a filled sealant (Ultraseal XT plus) were used. The pattern of resin tag formation in the four sealant materials were compared using SEM. For the microleakage assessment, 54 extracted human premolar teeth were randomly divided into 3 groups containing 18 premolars each. In each group, a conventional filled sealant and one of the three flowable composites were applied to occlusal fissures. The teeth were thermocycled(1200 cycles between $5^{\circ}{\pm}2^{\circ}C\;and\;55^{\circ}{\pm}2^{\circ}C$ with a dwell time of 30 seconds) and immersed in a 1% methylene blue solution for 48 hours. Each tooth was sectioned and examined to determine the extent of dye penetration. Three flowable composites and a filed sealant showed a similar resin tag formation pattern. The three flowable composites showed significantly more microleakage in each group than the filled sealant. The level of microleakage was similar in the three flowable composites. Flowable composites are not recommended as pit and fissure sealants because more microleakage can occur even when occlural fissures are mechanically widened.