• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.6
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• pp.50-55
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• 2011

The fluid power products are widely used in current industrial area such as automation of products and equipment assembly, high-tech machine tool, aircraft, train, and etc. As the development of industry is in progress, the development of the fluid power products is demanding and it is required in every industrial area. This research proposed a pneumatic system to evaluate displacement accuracy of the pneumatic actuator without external load and to analyze capability of integration of the valve system. The pneumatic system consisted of a combination of pneumatic actuator, four two-port valves, two three-port valves, two pressure valve, a check valve, two proximity sensors, and a program logic controller (PLC). The position controller is based on the PLC connected with the proximity sensors. The maximum air pressure applied for tests was $49.05N/cm^2$ and the displacement accuracy of a stroke was measured using a dial gauge. The supply- and discharge-side of air pressure and the length of the stroke of the pneumatic cylinder were varied The test of the position control of the pneumatic cylinder was carried out 50 times at each supply- and discharge-side air pressure of 24.53/34.34, 29.43/39.24, 34.34/44.15, and $39.24/49.05N/cm^2$ and replicated three times. The accuracy of the displacement of the pneumatic cylinder stroke increased as the supply- and discharge-side of air pressure increased with the stroke length of 133mm. Also the displacement accuracy increased as the stroke length increased with the fixed supply- and discharge-side of air pressure of the pneumatic cylinder as 34.34 and $44.15N/cm^2$, respectively. The most accurate displacement of the pneumatic cylinder was obtained at the supplyand discharge-side of air pressure of 39.24 and $49.05N/cm^2$, respectively, and strokes of 170 and 190mm.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.4
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• pp.436-444
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• 2018

Currently, the new substation automation uses the international standard IEC 61850 communication protocol. KEPCO is also constructing a new substation based on IEC 61850 from 2013 through the pilot application and research and development starting from 2007. However, there are few cases where existing substations(Transformer, T/L GIS, D/L GIS, etc.) have been used, and RTU based substations operating systems have been changed to SA substations based on IEC 61850. Therefore, the introduction of IEC 61850 in existing substation facilities has the advantage of enhancing the substantiality of the substation by reusing existing facilities, improving the interoperability with the latest substations introduced, and converting existing substations into systems suitable for unmanned operation. In this paper, we introduce a case of changing the existing RTU based substation operation system to digital substation using IEC 61850 field information processor, Ethernet switch and SA operation system. Also, IEC 61850 client authentication program and Wireshark, which is a packet analysis tool, verify IEC 61850 conformance and its feasibility.

• Journal of the Korean Society for Library and Information Science
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• v.24
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• pp.9-51
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• 1993

The purpose of this study is twofold: to investigate into general characteristics of the abstracting services in Korea and to discuss general directions of development of the abstracting services in the country. This study is designed to achieve the purpose by gathering and analysing data related to the abstracting journals published in the past ten years and by comparing the results with similar data gathered by the investigator in 1984. The major conclusions made in this study is summarised as follows. (1) Researchers and professionals working in limited numbers of subject fields are benefited by abstracting services of recent achievements in research and development in Korea. Those in most of the fields have essentially no abstracting services of such achievements. Even many researchers and professionals in the limited numbers of the fields that have some elementary abstracting services are not informed of research results in their fields because the abstracting journals are scattered in many narrow subjects and in many cases, the abstracting journals only cover publications in some specific forms and kinds. (2) Abstracting journals of general subjects, which are supposed to be of more or less help to the researchers in the subject fields that have no abstracting journals of their own, have rapidly increased in number in the past ten years. Most of such abstracting journals carry thesis and dissertation abstracts, and the rest those of research papers published in specific places, in specific forms, by specific institutes, and of reports of research projects sponsored by specific foundations. These abstracting journals are not of the kind that comprehensively provide general readers with current awareness of publications of research results in Korea. (3) Most of the abstracting journals existing in Korea are published by institutions of higher education and research institutes, and the rest by commercial publishers, industrial firms, libraries, information centers, government agencies, research foundations, learned societies, etc. Those which publish many titles are small in number and those publish one or two titles are large in number. The former is largely made up of institutions of higher education and research institutes. (4) Ten years ago, there was not a single publishing house that produced abstracting journals. Three commercial publishing houses now produce abstracting journals. As this change occurs, centers of excellence are founded and competitive elements are introduced in abstracting services. This change, in turn, is expected to improve quality of the other abstracting journals in Korea. (5) The abstracting journals published in Korea are classified by type into those of dissertations, research papers, journal articles, patent specifications in that descending order. The fact that Master's and doctoral dissertation abstracts are dominating in Korea is due to the irrational practice of publishing those abstracts at many institutions. (6) Most of the abstracting journals existing in Korea are published by national or government-supported research institutes in order to publicise their own research outputs. Their coverage of literature is normally narrow, and naturally their value to users is limited. (7) The abstracting journals published in Korea increased in number at the rate of $77.8-100\%$ every five years in the past twenty-five years. Most of the abstracting journals that ceased to be published during the period survived for two years. (8) Korean is the desirable language for the abstracting journals designed to be distributed within Korea. About half of the abstracting journals published in Korea is printed in Korean and the other half in foreign languages, and in Korean with foreign languages. All the abstracting journals in foreign languages are printed in English xcept one, which is printed in Japanese. (9) Some twenty percent of the abstracting journals in Korea is published monthly, bimonthly, and quarterly. Others are published annually, biannually, and irregularly. The latter may not function properly as a current-awareness tool due to long intervals between their issues. It is particularly undesirable that about half of the abstracting journals in Korea is published irregularly. Most of the abstracting journals published in Korea are distributed freely to individuals and institutions selected by the publishers. (10) The abstracting journals published by the use of computers increased drastically in the past ten years. The abstracting journals produced by the conventional type-setting method will probably disappear In Korea in another ten years to come. Automation of the production of abstracting journals does not simply mean technical, economic improvement of publishing processes but availability of machine-readable databases that can be used for other purposes, including the generation of other publications and the provision of machine literature searching capabilities. Necessary steps should be taken for this important development that is occurring in the abstracting services in Korea.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.7 no.1
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• pp.5-22
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• 1994

This paper attempts to define some general characteristics of the Abstracting Journals published in Korea as evidenced in those published during last ten years. This purpose is achieved by comparing the results of the two studies conducted by the author in 1984 and in 1994. Both studies were conducted to present the state of the art in the abstracting services in Korea. The major conclusions made in this paper are summarised as follows： (1) Researchers and professionals working in a small number of subject fields are benefited by the abstracting journals, which provide current-awareness services of recent achievements in research and development in Korea. Those in most of the fields have no abstracting journals of their own, and naturally they have no substantial abstract-ing services. Even many researchers and professionals in the fields that have some abstracting journals are not informed of research results in their fields because the abstracting journals are scattered in many narrow subjects and in many cases, the abstracting journals only cover publications in some specific forms and kinds. (2) Abstracting journals that cover more than two subject fields, which are supposed to be of more or less help to the researchers and professionals in the subject fields that have no abstracting journals published in their fields, have rapidly increased in number in the past ten years. Most of suh abstracting journals carry thesis and dissertation abstracts, and the rest, those of research papers published in specific places, in specific forms, by specific institutions, and of reports of research projects sponsored by specific foundations. These abstracting journals are not of the kind that comprehensively provide researchers in related fields with current awareness of publications of research results in Korea. (3) Most of the abstracting Journals existing in Korea are Published by institutions of higher education and research institutes, and the rest, by commercial publishers, industrial firms, libraries, information centres, government agencies, research foundations, learned societies, etc. Those which publish many titles are small in number and those publish one or two titles are large in number. The former is largely made up of institutions of higher education and research institutes. (4) The abstracting journals published in Korea are classified by type into those of dissertations, research papers, journal articles, patent specifications in that descending order. The fact that Master; and doctoral dissertation abstracts ate dominating in Korea is due to the irrational practice of publishing those abstracts at many different institutions. (5) Most of the abstracting journals existing in Korea are published by national or government-supported research institutes in order to publicise their own research outputs. Their coverage of literature is normally narrow, and naturally their value to users is limited. (6) Korean is the desirable language for the abstracting journals intended to be distributed within Korea. About half of the abstracting jornals published in Korea is printed in Korean and the other half, in foreign languages, and in Korean and in foreign languages together. All the abstracting journals in foreign languages are printed in English except one, which is printed in Japanese. (7) Some twenty per cent of the abstracting journals in Korea is published monthly, bimonthly, and quarterly. The others are published annually, biannually and irregularly. The latter may not function properly as a current-awareness tool due to long intervals between their issues. It is particularly undesirable that about half of the abstracting journals in Korea is published irregularly. Most of the abstracting journals published in Korea are distributed freely to individuals and institutions selected by the publishers. (8) The abstracting journals published by the use of computers increased drastically in the past ten years. The abstracting journals produced by the conventional type-setting method will possibly disappear in Korea in another ten years to come. Automation of the production of abstracting journals does not simply mean technical, economic improvement in publishing processes but availability of machine-readable databases that can be used for many other pur-poses, including generation of other bibliographical publications and provision of machine literature searching capabilities. Necessary steps should be taken for this important development immediately.