• Asian-Australasian Journal of Animal Sciences
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• v.30 no.12
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• pp.1667-1673
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• 2017

Antibiotics have long been of great benefit for people, both in the medical treatment of human disease and in animal food where they improve the growth performance and feed utilization during animal production. Antibiotics as in-feed supplements affect all stages of pork production, including the gestation, nursing, growing, and finishing stages, although the effects show stage-dependent differences. However, the use of antibiotics in animal feed has become a worldwide concern. This review describes why sub-therapeutic levels of antibiotic additives in animal feed have become an integral part of animal feeding programs for more than 70 years, particularly in pork production. It also discusses the threat of the long-term use of sub-therapeutic levels of antibiotics in pork production. In recent years, the effectiveness of in-feed antibiotics has tended to decrease. This review analyzes this change from various perspectives. First, the equipment used at pig farms has improved dramatically and is more sanitary. Worldwide, more pig farms use pig farrowing crates, gestation crates, piglet nursery crates, flooring devices, piggery ventilation and cooler systems, automatic pig feeders, piggery heating equipment, and artificial insemination systems. In addition, scientists have replaced the use of antibiotics with organic acids, fermented mash, probiotics, prebiotics, minerals, oligosaccharides, enzymes, herbs/flavors, and protein/amino acids, and have improved management and husbandry techniques. In addition, animal welfare legislation has been aimed at improving the quality of the floors and living space, ensuring that animals have permanent access to fresh water, and setting a minimum weaning age. Finally, the prospects and the possibility of replacing antibiotics in pork production are described, in line with recent research results.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.11a
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• pp.133-138
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• 2002

Recently, mega-float offshore structure is studied as one of the effective utilization of the ocean space. And mega-float structure are now being considered for various applications such as floating airports, container yard, offshore cities and so on. This mega-float structure is relatively flexible compared with real floating structures like large ships. when we estimate dynamic responses of these structures in waves, the elastic deformation is important, because vertical dimension is small compared with horizontal. The analysis of the dynamic response as it receives regular wave is studied. The finite element method is used in the analysis of structural section of this model. And the analysis is carried out using the boundary element method int eh fluid division. In order to know the characteristics of the dynamic response of the mega-float structures, effects of wavelength, water depth, and wave direction on dynamic response of the floating structure are studied by use of numerical calculation.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.5
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• pp.627-637
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• 1985

The combustion process and the performance of a diesel engine are seriously affected by the ignition delay period of the fuel used. Some methods for improving the combustion process in the engine cylinder are to well match the strength of air swirl with the space of sprays in the cylinder, to blend an ignition improver in the fuel, to inject a small amount of auxiliary fuel prior to main injection and so on. Recently, the improvement of fuel economy and the reduction of exhaust smoke and NO have been successfully achieved by supplying diesel engines with emulsified fuel. However, it is very difficult to know real combustion mechanism under such special conditions, because of many factors affecting on the combustion process in practical reciprocating engine. In the present paper, the combustion processes of diesel fuel and emulsion fuel were tried to improve and to observe by making contact with various lean pre-mixtures in the hot air stream duct. This hot air stream method has an advantage that the spontaneous combustion process can be observed under a simplified condition.

• Korean Institute of Interior Design Journal
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• v.22 no.5
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• pp.336-343
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• 2013

The study analyzed behaviors of users in cafeterias and spatial environmental images as well to understand what factors would affect the users' satisfaction in the cafeterias. The study also looked into how interior space factors would influence the users, what the users actually want from the cafeterias when they use them and lastly, what kinds of behaviors the users would do while in the cafeteria. Through those researches, the study proposed solutions to improve the users' satisfaction in cafeterias. As a field survey research, the study observed actual conditions of cafeterias at a university as conducting spatial environmental analysis to present ways to improve students' satisfaction in cafeterias at their university. In order to achieve the research goal, the study carried out a literature analysis and a survey and visited the cafeterias to understand both actual conditions and environments of cafeterias at a university. The study also had in-depth interviews with the students. The subject of the study was those college students who have been using four cafeterias at three campuses of D university. Data was collected via surveys, observations and interviews. With the students as the research subject, the study investigated and analyzed current status of the students' using of the cafeterias, actual utilization, spatial factors and satisfaction factors. The study was mainly developed with a survey conducted and by distributing basically 200 copies of the survey each to the campuses, the study gave out 200 copies each to Suseong Campus in Daegu and Oseong Campus in Gyeongsan but 400 copies at a time to Samsung Campus in Gyeongsan because it was the main campus and had two cafeterias. To sum up, each department was instructed to answer 20~40 copies of the survey in the end. Out of 800 copies in total, 188 copies from Oseong Campus, 153 copies from Suseong Campus and 386 copies from Samsung Campus which would add up to 727 were observed to be faithful enough to be used as statistics for the study.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.4
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• pp.837-846
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• 2013

Recently, new technologies based on wireless LAN is being studied because utilization on smart phone using Wi-Fi is increased. 802.11 b/g/a is universalized wireless LAN technologies based on ISM, the standard developed in 11's working group of IEEE 802. standardization about IEEE 802.11ac that overcame limitation on Blue-ray of IEEE 802.11n or uncompressed video transmission and IEEE 802.af's technologies using TVWS is being actively studied. In this paper, ability of transmission considering the security on AP operated by these technologies have measured and done a comparative analysis with existing wireless LAN environment ability of transmission measured when appling security is more stable than existing ability of transmission in an environment with obstacles and shorten of transmission time is confirmed as a result of analysis.

• Journal of KIISE:Databases
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• v.30 no.2
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• pp.176-183
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• 2003

Various techniques including histograms, sampling and parametric techniques have been proposed to estimate query result sizes for the query optimization. Histogram-based techniques are the most widely used form for the selectivity estimation in relational database systems. However, in the spatio-temporal databases for the moving objects, the continual changes of the data distribution suffer the direct utilization of the state of the art histogram techniques. Specifically for the future queries, we need another methodology that considers the updated information and keeps the accuracy of the result. In this paper we propose a novel approach based upon the duality and the marginal distribution to construct a histogram with very little time since the spatio-temporal histogram requires the data distribution defined by query predicates. We use data synopsis method in the dual space to construct spatio-temporal histograms. Our method is robust to changing data distributions during a certain period of time while the objects keep the linear movements. An additional feature of our approach supports the dynamic update incrementally and maintains the accuracy of the estimated result.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.6
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• pp.567-582
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• 2000

We propose a new way of managing flash memory space for flash memory-specific file system based on log-structured file system. Flash memory has attractive features such as non-volatility, and fast I/O speed, but it also suffers from inability to update in place and limited usage cycles. These drawbacks require many changes to conventional storage (file) management techniques. Our focus is on lowering cleaning cost and evenly utilizing flash memory cells while maintaining a balance between the two often-conflicting goals. The proposed cleaning method performs well especially when storage utilization and the degree of locality are high. The cleaning efficiency is enhanced by dynamically separating cold data and non-cold data. The second goal, cycle-leveling is achieved to the degree where the maximum difference between erase cycles is below the error range of the hardware. Simulation results show that the proposed method has significant benefit over naxve methods: maximum of 35% reduction in cleaning cost with even spreading writes across segments.

• Tunnel and Underground Space
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• v.25 no.3
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• pp.221-230
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• 2015

This study examined and analyzed several mine management software programs developed in domestic and oversea countries. In the oversea countries, many companies have developed and commercialized mine management softwares such as Dispatch, $Cat^{(R)}$ $MineStar^{TM}$ and FARA. These softwares provide many functionalities including real-time machine tracking, machine assignment optimization, productivity management, equipment health monitoring and remote control. For the domestic cases, this study reviewed two software programs (i.e., GEMISIMS, Truck-Shovel fleet optimization) developed by several researchers because there is no mine management software currently commercialized in Korea. In addition, this paper reports the two cases at the Jwaneng mine in Botswana and at the Robinson mine in United States where mine management software programs are used to support mine operations.

• Journal of Korean Society of Rural Planning
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• v.21 no.1
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• pp.129-141
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• 2015

This study classifies the types of spatio-functional differentiation in Korean island areas and analyses typical characters and suggests the development directions by each type. Eup/Myeon-level island areas are classified as six types by the factor analysis and the cluster analysis. First type is the traditional rural center. This type puts emphasis on maintaining phase as the central space and has to maximize development potential of the whole of settlement zone. Second type is the specialized region in manufacturing industry and the qualitative mutual growth of regional industries is able to be suggested. Third type is the specialized region in the neighborhood service provision. This type needs to devise the plan for utilizing potential customers actively and developing into the region specialized in tourism industry. Fourth type is the specialized region in tourism-support service functions. This type has to promote differentiated policies for maintaining amenity infra or value of countryside capital and preservation and utilization of resources by regional features. Fifth type is the fishing industry-dominated region. This type has to promote sustainable fishery development through the policy reflecting regional features and condition. Finally, sixth type is the sluggish region dominated with the traditional agriculture and fishery. This type is needed to aim at developing into the new food production base having the advantage of clean environment by strengthening support in specialized agro-fishery products. The existing researches on spatio-functional differentiation were mostly discussed with respect to land development, but this study highlights the difference in deal with the island areas distinguished from the condition of industry.

• Journal of the Korea Furniture Society
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• v.21 no.3
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• pp.216-228
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• 2010

Recently, there is a new issue, among the contemporary people, for new life style, such as green design and well being. This trend brought up the necessity that there should be alternatives for interior spatial design. In order to catch up with these new issues, the new convenient and environment friendly methods are in need. Space composition using setting-up is skill that can express both the structural aspect and esthetic because it represents traditional beauty into the contemporary age through the structural rigidity and formal beauty. Also the lumber, as main materials for setting up, is in line with well being life style and environment friendliness. The construction of structure by setting-up has advantages in terms of the reuse and the convenience in that the construction of structure is adjustable according to environment. And setting-up has enough plasticity not only because of its own role as linking the objects but also because of being framed by itself. Therefore setting-up will be a design element, if it is expressed outward. Thus, this study aims to give a guide line about how to apply the result from the evaluating that "what is the most suitable setting-up" and "what is the most suitable detail setting-up", based on that structural rigidity, decorativeness and the ease of works. As a result of evaluation, the most excellent types of setting-up in terms of structural rigidity are "Jangbu" and "Panjae" and "Yeongui". The most excellent types of setting-up in terms of decorativeness are "Panjae" and "Yeongui", and the most excellent type of the ease of work is "Mat". And also the most applicable detail setting-up for the utilization of spatial composition is proposed.