• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.1
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• pp.46-52
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• 2005

A marine environmental information system (MEIS) useful for optimal route planning of ships running in the ocean was developed. Utilizing the simulated marine environmental data produced by the European Center for Medium-Range Weather Forecasts based on global environmental data observed by satellites, the real-time forecast and long-term statistics of marine environments around planned and probable ship routes are provided. The MEIS consists of a land-based data acquisition and analysis system(MEIS-Center) and a onboard information display system(MEIS-Ship) for graphic description of marine information and optimal route planning of ships. Also, it uses of satellite communication system for data transfer. The marine environmental components of winds, waves, air pressures and storms are provided, in which winds are described by speed and direction and waves are expressed in terms of height, direction and period for both of wind waves and swells. The real-time information is characterized by 0.5° resolution, 10 day forecast in 6 hour interval and daily update. The statistic information of monthly average and maximum value expected for a return period is featured by 1.5° resolution and based on 15 year database. The MEIS-Ship include an editing tool for route simulation and the forecasting and statistic information on planned routes can be displayed in graph or table. The MEIS enables for navigators to design an optimal navigational route that minimizes probable risk and operational cost.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.467-474
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• 2017

The objective of this study is to analyze teachers' experience in the operation of outdoor play in an early childhood educational institute. For this purpose, the experience obtained in planning/operating the outdoor play in early childhood educational institutes, as well as the difficulties experienced in their operational process, were examined. The data was collected through interviews with eight early childhood teachers. In the results of the study, first, the teachers' perception of outdoor play was analyzed. The teachers considered outdoor play as meaningful in that the children could develop gross/fine-motor skills, have the chance to develop their sociality, relieve their stress, and also commune with nature through outdoor play. Second, regarding the plan/operation of the outdoor play activities, even though they aimed to provide the children with meaningful outdoor play activities through various materials and methods, most of the teachers could not put their original plans into practice, because of the numerous variables in the actual site. The teachers' difficulties included insufficient time, spatial limitations, and insufficient qualifications for play instruction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.6
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• pp.2484-2490
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• 2012

This study reports on the development and performance verification of cell simulation boards of simulator and the embedded program for board control of the battery management system (BMS) of electric vehicle (EV) cars, which manages the next-generation automotive lithium-ion battery pack. Here, we have improved the speed of the simulator by using operational (OP) amplifier and transistors that were connected in series. In addition, using a digital analog converter (DAC) in each channel, we have improved the performance by channel-to-channel isolation (isolation) as compared to the traditional methods. Furthermore, by constructing a current-limiting protection circuit, one can be protected from disturbance and, by utilizing a precision shunt resistor for the current sensor, we have increased the precision of the current control. In order to verify the performance of the developed simulator, we have performed the experiment 10 times, with values ranging from 0.5 V to 5 V, and a voltage drop step of 0.5 V. Significance analysis of experimental data, and repeatability tests were performed, showing an average standard deviation of 0.001~0.004 V, indicating high repeatability and high statistical significance of the current method and system.

• Strategy21
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• s.45
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• pp.33-59
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• 2019

There have many research papers to see China's evolution of maritime strategy and naval modernization in terms of its naval mind-set. However, this article focuses on assessing how China uses its all sorts of maritime strength to achieve 'a building maritime great power.' The aim of the article is to introduce a new perspective to this debate by analysing China's diversified ma maritime capabilities and a new way of implementation in maritime security strategy. In recent years, China has been developing not only unpredictable maritime military capabilities but also maritime supporting forces - Coast Guard and Maritime Militia. And recently China adopted up-to-date operational concept aimed at gaining military superiority in Asia-Pacific waters. By taking salami slicing strategy, gray zone strategy and cabbage strategy, China has been trying to exercise surpassing influences in regional maritime area, also in western Pacific region. This article provides a stepping stone to comprehend the aspect of China's recent maritime strategic actions, especially in Yellow Sea. In conclusion, this article suggests some policy recommendations for countering China's coercive maritime strategy. First, Korea should make sure a strategic concept of maritime security, instead of land warfare focused strategic concept. Second, it is needed to set up suitable naval forces for actively responding to neighbor nation's offensive actions.

• Journal of the Korean Society for information Management
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• v.37 no.1
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• pp.51-78
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• 2020

Recently, the emphasis on self-directed learning and lifelong education is increasing the importance of school libraries in the curriculum. Accordingly, various studies have been conducted mainly from a structural, institutional and operational point of view. However, more research is necessary on the micro topics such as school library users' autonomous intrinsic motivations in the sense that school libraries play key roles in autonomy-based self-directed education. This study aims at finding out what types of school library use motivations are more important and the degree to which the use motivations affect the school library service quality based on the self-determination theory. In addition, this study examines how the use motivations and the perceived service quality vary depending on the school grade of the library users. Based on a focus-group-interview pilot study, a questionnaire survey was administered on the effects of school library motivations on perceived library service quality to 588 students from 5 high schools and 2 middle schools in Seoul. When the service quality and its components, service affect, information control, and library as place were set as dependent variables, in all these four cases, intrinsic motivations were more significant than extrinsic motivations. In addition, when middle school students and high school students were selected as separate analysis target groups, the results of both analyses show that the higher the intrinsic motivations were, the higher the perceived service quality was. The contribution of this study is that it applies the self-determination theory to school library service, measures the influence of motivation type based on the theoretical basis, and focuses on micro aspects to improve school library services.

• Journal of the Korean Institute of Navigation
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• v.15 no.1
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• pp.12-47
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• 1991

This work aims to introduce the concept of microcomputer aided port design simulation methodology including the analysis of the mathematical models to be implemented and apply it to the Third Stage Busan Port Development Project. In the Busan case study, the size of the proposed turning basin of the new terminal, together with the operational strategies of berthing and unberthing, was examined, In addition, the safety on ship's entry and exit through the projected new breakwaters was ascertained. From the application of simulation to the Busan project, it was found that the proposed dredging area was not sufficiently wide enough for the modelled container ship to perform A time unberthing (in which the ship turns to port as she manoeuvres away from N.1. Berth with the assistance of tugs), especially in a strong easterly wind. It is therefore, recommended that Busan pilots should be advised to sue B type unberthing strategy, in which the ship goes astern from no.1 berth tot he turning area in front of No.2 berth(where the ship turns 180 degrees clockwise), especially when the wind is very strong, It is also recommended that a sea buoy be placed outside the new breakwaters, as this was found to improve the safety of ship manoeuvres through the breakwaters significantly . Another recommendation is that the Korean hydrodynamic Office carry out a detailed survey of the currents in the water area near the new breakwaters once they have been constructed. In addition, it is to be recommended that a current meter be placed at the recommended sea buoy to improve the safety of ship manoeuvres which could otherwise be jeopardised by eeroneos current information.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.12
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• pp.2249-2260
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• 2017

IMO (International Maritime Organization) has been providing GMDSS (Global Maritime Distress and Safety System) and mandating to install distress and safety systems according to SOLAS. Digital-HF(High-Frequency) coast station communication system maintains interoperability between ship and coast station and digital data exchange in maritime mobile service by digitizing existing analog base voice communication. In this paper, we analyze ITU-R M. 1798-1 established by ITU for digital HF communications and propose Advanced annex2 and new Annex 5 to improve the problems of the existing Annex 2 and Annex 4. The proposed OFDM protocol basically adopts ARQ (Automatic Retransmission Request) which retransmits when an error occurs in a half-duplex manner between an information transmitting side (ISS) and an information receiving side (IRS) and we propose a digital HF communication system and its operational concept which is more reliable and superior than the existing ITU-R M. 1798 by implementing technical development on implementation and performance improvement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.640-646
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• 2017

A GEN TEST of the auxiliary power unit of a T-50 series aircraft is performed as part of the operational test of its emergency power system on the ground before flight. At this time, the auxiliary power unit should be automatically turned off via the response signal of the ECU when power is not normally supplied to the emergency power system. If the correct operation of the emergency power system cannot be confirmed on the ground, it is not possible to proceed with the flight. This kind of defect is a major factor causing the operation rate of the aircraft to be decreased. The defect code identified by the ECU was confirmed as a defect in the inverter. However, the same defect was found after replacing the inverter. This report presents an improved method of identifying the cause of the defect by analyzing the response characteristics of the ECU and emergency power system and allows the ECU to be recognized as the cause of the defect if the inverter does not generate a voltage within a certain time. Also, the application of the improved method confirmed that it can satisfy the output request time of the emergency power system and effectively prevent the auto-shutdown of the auxiliary power unit.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.120-127
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• 2016

This study examined the dynamic characteristics of the gate to identify the optimal gate installation direction according to the installation direction. A 1:31 scale model was constructed for a 47.5m prototype gate using acrylic. The scaled weights were tuned by adding lead weights. The first step was to measure the natural frequencies of the model gates, and compare them with finite-element analysis of the prototypes as a calibration. The scaled model was tested in a 1.6 m wide concrete flume for two orientations to determine the effects of the gate orientation on structural vibrations. Vertical vibrations were measured under a range of operational conditions, including a range of bottom opening heights and different upstream and downstream water levels. For large bottom opening heights in the normal direction, relatively large vibrations were induced by vortices shed at the plate bottom that would strike the horizontal truss member. This phenomenon was avoided in the reverse direction. For small bottom opening heights in the normal direction, these vibrations were caused by a suction force that developed at the gate bottom. The gate model in the reverse direction was preferred because of its low overall vibrational response under general gate opening and flow level combinations.

• Journal of Korean Society of Rural Planning
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• v.21 no.3
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• pp.155-169
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• 2015

As an essential means to the exploitation of new demands, the export of agri-food has the price-supporting effect on the domestic agri-food and its expansion can be a good way to increase farms' income. Of course, to enhance farms' income under the liberalization of the market, it is necessary to have countermeasures considering various factors. To this end, the study understood the experiences of farms doing exports and looked into ways to improve them by reviewing their motivations to export, difficulties, requirements, etc. In this context, the study conducted the purposive sampling among tomato export farmhouses in Jeongseon-gun in the export enforcement phase and executed the theme analysis. The research findings and suggestions are as follows. First, in order to enhance the level of commercialization of Jeongseon-gun tomatoes and reinforce the trade bargaining power, it is necessary to form the consensus on policy and make the scaling of the site based on the strong organization power. To this end, it requires the active role of agricultural cooperatives that take a big portion of distribution in the site and distribute its profits directly to farmhouses. Second, it is necessary to set clear target markets for Jeongseon-gun tomato export farms and set sales strategies for each target market. That is, in order to expand the export of Jeongseon-gun tomatoes, after clarifying local sales and export sales, export farmhouses should focus on quality management and secure the quantity for export. Third, to expand the export to Japan which already has the foundation for the export of Korean tomatoes, and to new export countries of China, Russia, etc., it is necessary to set the 'Two-Track Strategies for Export Market (particular item for focus and particular area for focus)' through the building of network of tomato export areas in Gangwon-do. In conclusion, to expand the export of Jeongseon-gun tomatoes, agricultural cooperatives and leaders together should build the strong organizational power with farmhouses and secure the quantities for export. And, according to the 'Two-Track Strategies for Export Market (particular item for focus and particular area for focus)', export infrastructure and export operational system should be built and to do so, the solidarity of tomato export farmhouses in Gangwon area should precede.