• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.6
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• pp.578-586
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• 2005

Recently, due to the launch of digital broadcasting service, the demand of Flat Panel Display (FPD) is sharply rising. Among them, the PDP is expected to be one of the most promising digital displays of next generation because of its large screen size, high resolution, thinness and board field of view. Meanwhile, the PDP uses ADS (Address Display-period Separation) scheme which divide one subfield into address and sustaining period to express the grey scale of images. Since the output of sustaining power module Is mostly used for sustaining period, the load of the sustaining power module can be considered as a pulsating load. Due to this particular load condition, if the wide ZVS range of the power switches is not guaranteed, the hard switching causes large amount of switching loss and serious thermal problem in power module. In this paper, a high efficiency power conversion circuit for 60' PDP sustaining power module which achieves wide ZVS range with the help of additional ZVS tank is proposed. According to the various gating methods, the different operations of the proposed converter are presented. And, to confirm the properties of the proposed converter, an experimental prototype of 900W power converter is constructed md tested. As a result, more than $92\%$ of high efficiency is obtained at $10\%$ load condition, and the ZVS operation is achieved from full load to $10\%$ load condition.

• The Korean Journal of Archival Studies
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• no.65
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• pp.111-150
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• 2020

Social media, also known as the 'revolution of communication', has become a major means of communication and service in contemporary society. Unlike existing media, the advantage of being able to deliver interactive information is already beyond the level of use between individuals and government efforts to use it. In fact, local governments in Korea operate one or more social media services for various purposes, which promotes policies of local governments or provides prompt information to local residents. These social media records are based on public business and should be managed as records. However, the legal basis for managing records of social media in the area of public records management is currently small, and each local government does not recognize the need for records management. Social media operate by local governments are not only of different types but also difficult to manage as standardized guidelines. Nevertheless, minimal guidance is needed to manage and preserve social media records. The purpose of this study is to draw out the least common elements in the preparation of guidelines for social media record management. For this purpose, the guidelines and policies established by advanced countries that already systematically manage social media were analyzed and the items and characteristics were derived. In addition, the guidelines were checked for application by comparing actual social media records with social media archives. This study is meaningful in that it proposed components that should be included in the development of guidelines for the management of social media records in local governments through the actual status of social media archive operations.

• Journal of KIISE:Information Networking
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• v.29 no.4
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• pp.412-427
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• 2002

This paper proposes a restoration scheme based on mobility learning and prediction in the presence of the failure of mobility databases in mobile communication systems. In mobile communication systems, mobility databases must maintain the current location information of users to provide a fast connection for them. However, the failure of mobility databases may cause some location information to be lost. As a result, without an explicit restoration procedure, incoming calls to users may be rejected. Therefore, an explicit restoration scheme against the failure of mobility databases is needed to guarantee continuous service availability to users. Introducing mobility learning and prediction into the restoration process allows systems to locate users after a failure of mobility databases. In failure-free operations, the movement patterns of users are learned by a Neuro-Fuzzy Inference System (NFIS). After a failure, an inference process of the NFIS is initiated and the users' future location is predicted. This is used to locate lost users after a failure. This proposal differs from previous approaches using checkpoint because it does not need a backup process nor additional storage space to store checkpoint information. In addition, simulations show that our proposal can reduce the cost needed to restore the location records of lost users after a failure when compared to the checkpointing scheme

• Korean Security Journal
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• no.16
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• pp.357-371
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• 2008

Currently, the security operations in nation's key foundations in Korea are performed by private police and special security guard in accordance with the Private Police Act and Security Business Act, respectively. In 1960s, The Korean Government introduced the private police system in terms of the national security issues, but it was just a hurriedly-set plan on the basis of Japanese Sunsa system as by that time there was no such system revitalized. However, the special security guards could offer wider range of security services including those of the private police with the enactment and revision of the Security Business Act 1976 and April 2001, respectively. Moreover, the expectations and interests rose over the special security guards in nation's key foundations after 9.11Terror Event in the U. S. 2001. However, as we investigated the current education/training system for the special security guard, we found that such education/training which is not activating the specialty of special security guard will not respond to the social demands. Special security guard owns its own characteristics other than those of general security guard as they are in service in nation's key foundations. Thus, the effcient management and training for the special security guard is the most important matter for the safety and security of nation's key foundations. Therefore, the well-educated special security guard through the reorganized and specialized education/training for the protection of nation's key foundations is expected to offer qualitatively improved security services.

• Journal of Korean Society of Transportation
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• v.21 no.4
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• pp.17-27
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• 2003

In general, an airport access system has influenced on airport terminal operation. The congestion and delay in service facilities at an airport are definitely depended on the patterns of passenger arrival behavior and time spent in a terminal. Therefore, it is necessary to analyze the passenger arrival behavior at an airport to improve the operations at passenger terminal. Passenger arrival patterns to an airport are mainly depended on factors such as the length of access time. reliability of access time. and provision of transport modes, etc. The focus of this paper is to estimate the relationship between the length of access time and passenger's total time spent to board aeroplane. For this, passenger surveys were conducted at the Gimpo International Airport for a large airport and Sacheon Airport for a small size airport. The mathematical relationship between arrival time at an airport prior to the scheduled time of departure(STD) and access time spent was then estimated. It is considered that the results of this study can be used to reduce congestion and delays, thereby to improve the efficiency of the passenger services at the airports.

• Korean journal of food and cookery science
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• v.19 no.4
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• pp.477-492
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• 2003

The purposes of the study were to establish HACCP-based standards and guidelines for conducting a plan review to build, or renovate, hospital food service establishments, and ensure the safety of foodservice and reduce the risk of food borne illness. The scope of the study included suggestion for the planning of hospital foodservice facilities: layout, design, equipment and modeling. The results of this study can be summarized as follows: 1) The development of a foodservice facility plan based on the results of a survey, literature reviews and the results of interviews with foodservice managers from 9 general hospitals. This was composed of operational policies in foodservices, layout characteristics, space allocation, selection, design, specification standards for equipment and the construction principles of foodservice facilities. 2) Two foodservice facility models were developed, one for general hospitals with 900 beds (2,000 patients and 2,500 employee meals per day) and the other for general hospitals with 300 beds (600 patients and 650 employees meals per day). 3) The suggested kitchen space requirements for the foodservice facility models were 341.2 ㎡ (W 17,100mm x L 23,700mm) and 998.8㎡ (W 35,600mm x L 32,800mm) for the 300 and 900 beds hospitals, respectively, with both designs being rectangular. The space requirements for the equipment, in relation to the total operational area, in terms of ratios were 1:3.5 and 1:3.8 for the 300 and 900 beds hospitals, respectively. The recommended space allowances per bed for the developed foodservice facility models were 1.15 ㎡ and 1.11 ㎡ for the 300 and 900 beds hospitals, respectively, which were increased by more than 30% compared to those suggested in the precedent study, and considered appropriate for the implementation of the HACCP system. 4) The hospital foodservice facilities plans and models were developed based on the general sanitation standards, guidelines and the HACCP system, and included foodservice facility layout, product flow, physical separation between contaminated and sanitary areas, foodservice facility specifications with a 1/300 scale for a 300 bed, and a 1/400 scale for a 900 beds blueprint. 5) The main features of the developed foodservice facility plans and models were; physical separation between contaminated and sanitary areas to prevent cross contamination, product flow in one direction from the arrival of the raw material to the finished product, and separation of different work areas and the process of receiving & preparation of products, refrigeration & storage, cooking, assembly, cleaning & disinfection, employee areas and janitorial facilities. The proposed models from this study were presented as examples for those wanting to build, or renovate, their facility for the production of foods.

• The Journal of the Korea Contents Association
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• v.19 no.10
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• pp.685-697
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• 2019

The study aimed to analyze the structure of China's passenger railway network in the years of 2008, 2013, and 2018, respectively. At the same time, it tried to investigate its derivative impact on the patterns of Chinese urban network. The analytical tool was based on the NetMiner4.0. In order to measure network characteristics of China's passenger railway network, it primarily focused on the degree centrality, betweenness centrality, and closeness centrality. First of all, the higher degree centralities, with a few exceptions, were observed in BeiJing, ShangHai, GuangZhou, WuHan, XiAn, ChengDu, HaErBin, and ShenYang over a decade. In contrast, the higher betweenness centralities were recorded in cities of higher development potential including WuLuMuQi, GuiYang, ShenYang, and KunMing. The closeness centrality analyses confirmed the fact that most metropoles like BeiJing, ShangHai, and GuangZhou kept the highest train accessibility during the same research period. At the same time, the opening up of a new stretch of high speed railway network has consecutively strengthened connectivity between BeiJing and TianJin. Owing to unprecedented development of railway traffic and its extensive operations, this study believes that Chinese major cities, without interruption, would pursue a series of urban policy alternatives geared towards railway stations-oriented networking and competitively try to extend their network ranges.

• Korean Journal of Plant Resources
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• v.32 no.5
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• pp.589-614
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• 2019

To investigate the distribution of vascular plants growing at Mt. Guryong, we surveyed from March in 2016 to October in 2017. The flora of Mt. Guryong was classified as a total of 526 taxa comprising of 87 families, 298 genus, 449 species, 4 subspecies, 63 varieties, 10 forma. Among them, the endemic plants in Korea were investigated as 10 taxa of including Pseudostellaria coreana (Nakai) Ohwi. The Korean rare plants species were investigated as 16 taxa, among them degree of CR investigated as 1 taxa of Cypripedium macranthum Sw., VU investigated as 5 taxa of including Rhododendron micranthum Turcz., degree of LC investigated 9 taxa of including Clematis koreana Kom., degree of DD investigated 1 taxa of Adenophora grandiflora Nakai. Endemic plants were investigated as 14 taxa of including seudostellaria coreana (Nakai) Ohwi and The floristic special plants were a total of 84 taxa such as 2 taxa in degree V(in cluding Polypodium virginianum L.), 7 taxa in degree IV (including Anemone reflexa Steph. & Willd.), 21 taxa in degree III(including Celtis aurantiaca Nakai), 22 taxa in degree II (including Thelypteris phegopteris (L.) Sloss.) and 31 taxa in degree I (including Cimicifuga simplex (DC.) Turcz.) was carried out to provide basic data. The naturalized plants were investigated as 37 taxa of including Chenopodium ficifolium Smith., Thlaspi arvense L., Rumex crispus L. and the percentage of urbanization index was 11.53%, the naturalized ratio was 6.99% respectively.

• The Korean Journal of Archival Studies
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• no.16
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• pp.257-302
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• 2007

The use of records has been regarded as the ultimate goal of preserving records, and reference services are considered key tasks in records management. Particularly in Korea where the importance of archives and records management is not recognized sufficiently, we need to help the public recognize the importance of institutions, managing archives, and archives kept in the archives, and create new uses. In order for archives to notify archives, institutions and managing archives to potential users, they can use publications, exhibitions and education programs. In foreign countries, services such as public programs and outreach services have already been being executed by archives in order to publicize the archives actively to the public, and various supports are provided so that people can use archives in educational activities. What is more, publishing and exhibition programs are also linked to education, which can increase the use of archives and promote archives culture. Thus, archives play important cultural and educational roles. As archives' roles are being expanded and local archives are being established compulsorily in Korea, archives should play their roles not just as administrative agencies collecting official documents but also as cultural and educational institutions providing various forms of information and education. Creating new demands for important archives by notifying such archives through public programs approaching users, they should find ways for laying the ground for their existence. The objectives of this study are to look for the method of public program operation suitable for the Korean situation, to define abilities and roles required to archives as program planners, and ultimately to increase the use of archives and contribute to the settlement of archives culture.

• The Korean Journal of Archival Studies
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• no.15
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• pp.3-37
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• 2007

Until now, archives of colonial era preserved in each public institution including National Archives & Records Service can be called as the results of colonial chosun government general's records management activities. However, it is a fact that only the fragment of the archives from colonial era remained in public institutions without maintaining integrity of record. Therefore, it is virtually impossible to restore operations process of the era only with current records. It is somewhat because some records were institutionally abrogated by valuation selecting standard of colonial chosun government general, but it is more likely the result of systematic destruction of documents and records upon liberation. On the other hand, although records that were being preserved by colonial chosun government general's acquisition policy escaped the systematic abrogation, the scope and target of the historical records were changed according to acquisition policy. Historical records managed by each inquiry agency of colonial chosun government general were collected to be used for fundamental information of colonial rule or compilation of Chosun history. However, archives collected by colonial chosun government general could not escape partiality as a goal for colonial rule had priority over the standpoint for recording Korean society. Although records management system of colonial chosun government general was introduced from Japanese government's system, it clearly shows colonial characteristics in the process of collecting Chosun's historical records and its use.