• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.577-582
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• 2020

Electricity produced at power plants is distributed to consumers through several stages of substations. At this time, an ultra-high voltage transformer is needed in the initial transmission stage to transmit a voltage suitable for each consumer. A high voltage, non-uniform electric field is formed at the end of the winding of the ultra-high voltage transformer, which carries a risk of dielectric breakdown. The winding of the ultra-high voltage transformer is an electrode, which is the key to converting the magnitude of the voltage. A non-uniform electric field is formed along the shape of the winding end, resulting in high electrical stress. The static ring installed at the upper and lower ends of the winding is used to disperse the stress at the winding end. Several variables should be considered when designing a static ring. Among them, this study examined how the curvature of the static ring, the thickness of the insulating paper, the number of barriers, and barrier thickness affect the electrical stress of the static ring using the Finite Element Method. Suggestions to be considered when designing the static ring are proposed through the FEM results.

• Journal of the Korean Applied Science and Technology
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• v.35 no.3
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• pp.865-875
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• 2018

Selection of optimum reaction conditions during deoxygenation process of palm oil is essential factor to obtain the maximum yield of bio-jet fuel. In this context, the deoxygenation of palm oil was carried out in a fixed bed reactor with an internal diameter of 1 inch loaded with a 1 wt.% $Pt/Al_2O_3$ catalyst. The composition of the organic liquid product(OLP), which can be utilized as a transportation fuel through the upgrading process, was analyzed by a gas chromatography method. The palm oil/hydrogen ratio and hydrogen pressure in the feed affected the decarboxylation(DCB) and hydrodeoxygenation(HDO) reactions, resulting in a change in the composition of the OLP. As the reaction temperature increased, the continuous cracking reaction of the deoxygenation product was promoted and the product composition in the $C_5{\sim}C_{14}$ region was increased. Thus, the results can help to understand the characteristics of deoxidation reaction of palm oil as well as the subsequent process, hydro-upgrading, to obtain the maximum yield of bio-jet fuel.

• The Journal of the Korea Contents Association
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• v.9 no.8
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• pp.129-137
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• 2009

While the broadband network and multimedia technologies have been developing, the commercial market of digital contents also has been widely spreading with recently starting IPTV. As the IPTV services are getting to be generalized and popularized, the contents protection and authentication system tends to draw more attentions. So we need a system that can protect contents and allow only authenticated person to use right service by controling user authority and using content encryption. Until now, the conventional protection and authentication system is taking advantages of merits both in CAS and DRM. But the weak point of this system are in high costs, complexity and using HW. For resolving these problems, in this paper, we proposed IPTV contents protection and authentication system using OTP. When we transmit the content encrypted by OTP key using contents delivery technology, we operate XOR with contents using another settop-box's OTP key which was transmitted from distribution server. And contents are reconstructed and transmitted to the settop-box, In the end, downloaded content are encrypted by OTP key and are superior in content protection when contents redistribution. Since OTP use double-authentication elements in encryption process, this method is excellent in content protection. And it is very effective in cost aspect because it could be implemented by SW program. Another benefit is that we can shorten the development time period. In this paper, we propose and find its possibility as a new content protection and authentication method suitable for IPTV services.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.661-671
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• 2018

Domestic studies on steel plate concrete structures have focused on nuclear structures with high strength. In this study, the SC structure was applied to the general structure, and the SC structure that is advantageous in terms of safety and construction was limited to a special structure. As a basic study for applying SC, this paper proposes basic design information of a SC structure applying cement concrete to plan the structure, which is suitable for eco - friendliness by replacing concrete cement, an important factor in a SC structure, with blast furnace slag. This study examined the compression characteristics and the effective length factor under central compression load. To calculate the effective length factor, the Euler column theory was applied without applying plate theory. The effective length factor was calculated from the yield strength of the steel plate, buckling of the steel plate, and the point at which the concrete was broken. In addition, this study examined whether the maximum compressive strength meets the national and international reference equations with the slenderness ratio (B/t) as a parameter. By analyzing the buckling of the specimen by applying the column theory and selecting the strain of the measured steel plate, the effective length factor was analyzed and compared with the value presented in the reference equation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.490-499
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• 2017

In recent years, the introduction of complex systems analysis based on various variables has become more active in order to identify and analyze complex problems of Modern Society. Prediction of patients' spatial perception and usability according to the spatial arrangement of the outpatient department is a very important factor for providing high quality hospital service. For objective analysis, the standard program procedure and analysis index for the diseases of the elderly were prepared and the uniformity of the atmospheric space was evaluated through heat map analysis and quantitative analysis. In this study, 73 cells were installed and simulated to analyze the uniformity of the four alternatives according to the change of the arrangement of the medical care space, receiving space, and consultation space using the complex system analysis method for the nursing hospitals. The resulting density was derived. The results are as follows. 1)The layout of the reception space has the greatest influence on the total spatial density of the waiting space. 2) The uniformity of the waiting space can be increased by separating the examination space and the examination space. 3)The closer the location of the receiving space is from the entrance, the greater the density of the waiting space. Finally, this study applied discrete event simulation to the evaluation of uniformity of atmosphere space, and proved that the actor - based model can be utilized for utilization and evaluation as spatial analysis methodology.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.865-871
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• 2011

Presently, the location and direction information are certainly needed for the autonomous vehicle of the ship. Among them, the direction information is a essential elements to automatic steering system. And the gyro-compass, the magnetic-compass and the GPS compass are the sensor indicating the direction. The gyro-compasses are mainly used in the large-sized ship of the GMDSS(Global Maritime Distress & Safety System). The precision and the reliability of the gyro-compasses are excellent but big volume and high price are disadvantage. The magnetic-compass has relatively fine precision and inexpensive price. However, the disadvantage is in the influence by the magnetism object including the steel structure of a ship, and etc. In the case of the GPS compass, the true north is indicated according to the change of the location information but in case of the minimum number of satellites or stopping of a ship or exercise in the error range, the exact direction cannot be obtained. In this paper, the performance of the GPS compass was improved by using the least-square curve fitting method for the mutual trade off of the angle sensor. The algorithm which improves the precision of an azimuth by applying the weighted value according to the size of covariance error was proposed with GPS-compass and magnetic compass. The characteristic and the performance of the proposed algorithm were analyzed and verified through experimentation. The applicability of the proposed algorithm was shown through the experimental result.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2873-2878
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• 2009

Since Germany was unified in 1990, Korea became the only country that has the division in the world. This division has various bad effects on Korea's status with not reliable security, forfeited national impression, loss of tourism income and so on. Kim Jung-Il national defense committee chairman is the current dictator of North Korea which is a socialist state. Even if he is getting old, his successor is not proclaimed. In this situation, his sudden aggravation of health can cause seriously bad effects on diplomatic relations especially with South Korea. Therefore, the health information about Kim Jung-Il national defense committee chairman will be very important information. In order to deal this problem, we propose the method of extracting the Kim Jung-Il national defense committee chairman's health from his pictures which are recently open to the public by employing the diagnosis Ocular Inspection used in Oriental medicine. n order to get an accurate result, revising the Kim Jung-Il national defense committee chairman's pictures, which are not taken in a controled equal situation, is necessary. Therefore we employed the color analysis process with color revising and color differential comparing process without color revising. With these processes, we can make diagnosis of his diabetes and complications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.631-638
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• 2017

In the age of the Fourth Industrial Revolution, lifestyle and industrial structures are faced with evolution from IT-based automation to the intelligent stage, demanding talents with software capabilities in various fields. Reflecting these demands, the government has enhanced basic software education for non-majors in elementary and secondary schools as well as universities. In this study, the software convergence education of Non-Majors is proposed to improve the general problem solving ability based on computational thinking and the software convergence ability in the field of their own by developing robot activity. The subjects of this study were 91 students, who were composed of various majors. The class was designed with computing thinking, convergence elements, and creative robot activity. The study was conducted for 13 weeks. To examine the effects of software convergence education through the creative robot activity, this study observed changes in the students' learning outcomes, satisfaction with creative robot activities, and perceptions of other disciplines after class based on pre-diagnosis surveys. The survey asked 12 questions including an understanding of the learning contents, overall satisfaction with multidisciplinary collaborative learning, understanding of other disciplines, and self-evaluation of problem solving ability through creative robot activities, which were compared with that before the class. They answered that their ability was improved.

• Journal of the Korean Society for information Management
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• v.17 no.2
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• pp.207-229
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• 2000

The lack of an understanding of the characteristics of a specific user group in computer-based information systems in libraries hinders library and information science professionals in grasping users' needs and making the best decisions when designing, acquiring, and managing information systems. The objective of this study was to provide information on the characteristics of specific user groups such as male ＆ female student groups. undergraduate ＆ graduate ones, Sciences and Humanities majored ones etc. This study also provides system developers (vendor) and adopters with users' needs and the merits or demerits of a specific system on the basis of students' evaluation. For the purpose, questionnaire was prepared and administered to Korean college students in the city of Taegu, Korea and adjacent area. One hundred and seventeen usable questionnaires were obtained and analyzed. These were analyzed using descriptive, inferential statistics. and SPSS software. The major findings of this study are: (1) Gender of the students affects the preference for the type of OPAC system selected more than that of academic level of study, age, and academic major; (2) The domestic in-house OPAC systems in Korea affect the user preference of system much more than that of foreign package ones; (3) System designers should prepare and use professional terms or abbreviations for system users more carefully, and explain them in detail; (4) Most of users preferred package OPAC systems to in-house ones, and preferred GUI systems to Telnet-based ones. Also, there was a significant difference between them. Conclusions are drawn from the findings in this paper, and recommendations are proposed when designing, adopting, or managing a new system. Topics for future studies on the characteristics of OPAC systems and their user are also suggested.

• Journal of Korea Technology Innovation Society
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• v.14 no.4
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• pp.736-760
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• 2011

The importance of new renewable energy is emphasized not only new growth engine but also the key solution for the exhaustion problem of fossil energy and environment problem. For the steady growth of new renewable energy industry, securing related labor force is an essential factor. In this study, the status on labor force of new renewable energy industry was identified and forecasted the labor force demand of new renewable energy in 2015 by reflecting the industrial growth outlook on the new renewable energy. For the quantitative analysis methodology, the stock approach of Bureau of Labor Statistics (BLS) of the United States was applied. Also by performing survey on the experts, the opinions of experts on supply and demand of new renewable energy labor force or worker training programs have been gathered. As a result of study, it has been analyzed that nearly 20% annual growth rate will be shown as the labor force demand in the field of new renewable energy industry increases from 14,100 people in 2010 to 33,200 people in 2015. In the survey on experts, we could find that a plan for supplying labor force must be prepared promptly in order to accomplish new renewable energy supply objectives and industrial growth objectives by our country in the future as the supply of new renewable energy labor force is currently insufficient. Also, it has been analyzed that the effort for deciding the proper new renewable energy labor force training program standard will be necessary. This study result could be used as a material of labor force training plan for the steady growth of new renewable energy industry in the future.