• Journal of Satellite, Information and Communications
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• v.1 no.2
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• pp.8-15
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• 2006

Under Resolution 122 (Rev. WRC-03), ITU-R is invited to study, as a matter of urgency, power limitations applicable for HAPS ground stations to facilitate sharing with space station receivers in the bands 47.2-47.5 GHz and 47.9-48.2 GHz. However, there have been no studies on this issue. Recommendation ITU-R SF.1481-1 which was developed during past study period, provides methodology and system characteristics for analyzing the sharing feasibility between systems in the FS using HAPS and systems in the FSS. System characteristics for a typical HAPS in the bands above are also given in Recommendation ITU-R F.1500. This paper provides the results on power limitations applicable for HAPS ground stations in accordance with Resolution 122 (Rev. WRC-03). As already shown in ITU-R Recommendation the results show that a sufficient separation distance is required for sharing between HAPS ground stations and FSS satellite systems. We obtain some examples of the sharing conditions considering reducing the power level of HAPS ground stations and using the antenna beam pattern with the low sidelobe to decrease the interference level affecting FSS satellite receiver.

• Journal of Satellite, Information and Communications
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• v.1 no.2
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• pp.45-50
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• 2006

A satellite and ground stations which are developed in a program are tested whether the interface between the satellite and ground is well established before satellite operations. These compatibility tests are performed when the satellite is connected with the ground stations after all satellite and ground stations requirements are verified. The content of the RF compatibility test is to check whether the interface requirements which are described on the Interface Control Document are well developed. During the early operation phase and tentative contingency operations of the satellite, KARI ground station uses other oversea ground stations which are located worldwide according to contract between the KARI and the contractor. Since oversea ground stations were not developed for the designated space program, system integrator should check whether the oversea ground stations are satisfied with interface requirements. Using the RF suitcase, RF interface and the content of RF communication can directly be verified during RF compatibility test on oversea ground station without KARI ground station's support. The RF compatibility test using RF suitcase was performed oversea ground stations as well as KARI ground station located on Korea. The content of RF compatibility test was standardized in order to be used at any oversea ground stations, especially fitted for the operations concept of launch and early operations phase. The test content would be RF characteristics, protocol, command loop test, telemetry loop test, and ground station interface test.

• Journal of Satellite, Information and Communications
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• v.12 no.4
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• pp.78-86
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• 2017

Japan has a lot of interest about weapons systems development of surrounding national and has invested heavily in securing intelligence assets to get information about them, because of conflict issues between Japan and Russia with four northern islands, China with Senkaku Islands and entry policy into the Pacific. Japan has used a large budget to detect and intercept ballistic missile for reasons of the launch of the Taepodong missile in 1998. After took over SIGINT equipments which U.S. force had operated in 1950s~1960s, Japan made a technological analysis and advanced IT technology to produce superior equipments. Japan's SDF has installed them in 19 locations across Japan. In addition, Japan's JASDF has installed advanced early warning RADAR to detect aircraft and high speed ballistic missile entering JADIZ with S-band in 28 locations across Japan. It is possible to detect missile launch preparations, engine tests, and launch moments at any time for operation of 6 satellites high resolution reconnaissance system and 6 aegis ships. In close cooperation with the US, Japan is accessible to the SBIRS networks which detects the launch of a ballistic missile in neighboring countries. In the future, Because the United States wants Japan to act as part of the United States in East, south Asia, it is believed that the exchange of intelligence on the surrounding countries between two countries will be enhanced.

• The Journal of the Korea Contents Association
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• v.20 no.8
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• pp.513-521
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• 2020

Launched in August, 2016, the online public benefit project ANT FOREST has planted more than one hundred million trees in desertification areas and is currently continuing on with its activities. It is a fruit of online communications network development, and the public benefit project based on this puts more emphasis on the spirits of public interest rather than the investments of public services, unlike traditional public benefit activities. Hence the purpose of this study is to figure out the interaction between the users supporting the online public benefit and the public benefit progress online. The study was divided into 4 stages in order to find out the interaction, key factors for users to continue to support online public interest. First, preceeding studies on online public benefit will be reviewed to understand the characteristics of online public benefit. Second, determine the public benefit nature of ANT FOREST and investigate the project progress. Third, review the usage rate of ANT FOREST and categorize the properties of users. Fourth, interview was conducted to direct the interaction between the online public benefit project and the user. In conclusion, the online public benefit project completes the public benefit process through the user, the operator, and the supporter, the important factor connecting the energy connecting the process in cyber space and the public benefit activity in reality is the sense of participation, and the user continues the public benefit project through this sense of participation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.3
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• pp.273-281
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• 2002

Determination of sediment type is generally based on ground truthing. This method, however, provides information only for the limited sites. Recent developments of remote classification of seafloor sediments made it possible to obtain continuous profiles of sediment types. QTC View system, which is an acoustic instrument providing digital real-time seabed classification, was used to classify seafloor sediment types in the Suyoung Bay, Pusan. QTC View was connected to 50 kHz echo sounder, All parameters of QTC View and echo sounder are uniformly kept during survey. By ground truthing, the sediments are classified into seven types, such as slightly gravelly sand, slightly gravelly sandy mud, gravelly muddy sand, clayey sand, sandy mud, slightly gravelly muddy sand, and rocky bottom. By the first remote classification using QTC View, four sediment types are clearly identified, such as slightly gravelly sand, gravelly mud, slightly gravelly muddy sand, and rocky bottom. These are similar to the result of the second survey. Also the result of remote classification matches well with that of ground truthing, but for sediment type determined by minor component. Therefore, QTC View can effectively be used for remote classification of seafloor sediments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11B
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• pp.1346-1356
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• 2011

Transportation has been playing important role in our society by providing for people, freight, and information. However, it cuts its own throat by causing car accidents, traffic congestion, and air pollution. The main cause of these problems is a noticeable growth in the number of vehicles. The easiest way to mitigate these problems is to build new road infrastructures unless resources such as time, money, and space are limited. Therefore, there is a need to manage the existing road infrastructures effectively and safely. In this paper, we propose a road reservation scheme that provides fast and safe response for emergency vehicles using ubiquitous sensor network. Our idea is to allow emergency vehicle to reserve a road on a freeway for arriving to the scene of the accident quickly and safely. We evaluate the performance by three reservation method (No, Hop, and Full) to show that emergency vehicles such as ambulances, fire trucks, or police cars can rapidly and safely reach their destination. Simulation results show that the average speed of road reservation is about 1.09 ~ 1.20 times faster than that of non-reservation at various flow rates. However, road reservation should consider the speed of the emergency vehicle and the road density of the emergency vehicle processing direction, as a result of Hop Reservation and Full Reservation performance comparison analysis. We confirm that road reservation can guarantee safe driving of emergency vehicles without reducing their speed and help to mitigate traffic congestion.

• Korean Journal of Remote Sensing
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• v.33 no.2
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• pp.189-199
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• 2017

Thisstudy quantitatively analyzed the research trendsin the use ofICT ofthe environmental field using the text mining technique. To that end, the study collected 359 papers published in the past two decades(1996-2015)from the National Digital Science Library (NDSL) using 38 environment-related keywords and 16 ICT-related keywords. It processed the natural languages of the environment and ICT fields in the papers and reorganized the classification system into the unit of corpus. It conducted the text mining analysis techniques of frequency analysis, keyword analysis and the association rule analysis of keywords, based on the above-mentioned keywords of the classification system. As a result, the frequency of the keywords of 'general environment' and 'climate' accounted for 77 % of the total proportion and the keywords of 'public convergence service' and 'industrial convergence service' in the ICT field took up approximately 30 % of the total proportion. According to the time series analysis, the researches using ICT in the environmental field rapidly increased over the past 5 years (2011-2015) and the number of such researches more than doubled compared to the past (1996-2010). Based on the environmental field with generated association rules among the keywords, it was identified that the keyword 'general environment' was using 16 ICT-based technologies and 'climate' was using 14 ICT-based technologies.

• Korean journal of communication and information
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• v.31
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• pp.85-111
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• 2005

This paper aims at dealing with the communication of Korean gong sound. It is based on 'music-spirit theory' of Han-Gi Choi and Mead's 'symbolic interactionism', and does this by interpreting the message of gong sound that is mentioned in Korean literature. The gong sound brings out the message of symbolizing evaporation of Korean people's joy and regrettable matters in the playing yard by regulating of breathing according to the steps. By the novel "Gong Sound" of Sun-Tae Moon Korean gong sound has a message of people's joy, anger, avarice, anxiety and sorrow. In Jeong-Rae Jo's novel "Arirang" the Korean Gong Sound includes a message of evaporation of people's regret and raises the national spirit during the Japanese Imperialism. By Jeong-Ja Yoo's collection of poems, "The sound of flower breathing carried by gong sound", the Korean gong sound carries a message of a roar of spirit and breathing of the spring flower. In conclusion, the Korean gong sound is a sublime sound of sky which carries the message of symbolizing evaporation of people's joy and regrettable matters through the sound communication in the open space, and awakes us to a method of breathing with sky.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.2
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• pp.194-205
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• 2006

The purpose of this study is to develop a pedestrian multi-agent model and simulation system using multi-agent theory, which may be utilized as a planning support system for building a comfort and safe environment of pedestrian street. Differing from existing pedestrian models, however, every single pedestrian was regarded as an individual agent in the model. Multiple agents like multiple pedestrians in the street then maintain their own characteristics and respond to surrounding environment. In addition their moving behavior are made by their own decision rules that they have or had acquired through the interactive communications or learning between agents like real world. After verifying the model validation, as the $R^2$ between the predicted value and observed value was up to 0.781, the developed model was applied to Gazwa district within Gyeongsang university village. The simulation system was developed by Flash MX action scripts and the physical environment of the streets was configured with the digital map and ArcGis within computer virtual space. The attribute data of buildings such as type and size of commercial business were collected through the field survey and combined with physical features. Then the effect of the variation of building attractiveness and the occurrence of street events to pedestrian environment were simulated. Through the experiments this study could make suggestions to improve pedestrian environment.

• Journal of The Korean Association For Science Education
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• v.37 no.6
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• pp.1063-1073
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• 2017

This study analyzed the difficulties elementary school students have in role-playing analogy activities for concept learning of heat transfer. Eleven fifth graders were given an orientation class on role-playing analogy activity, a class for concept learning of heat transfer as presented in a textbook, and then they performed the role-playing analogy activity with concepts of heat transfer. After the classes, researchers investigated the difficulties students encountered through questionnaires and interviews. The following are results of the research: Difficulties that students faced in role-playing analogy activity can be classified into five types. First, students encountered difficulties in expressing the analogy. The students who had difficulties in expressing the analogy focused on expressions outside the science concepts or lacked understanding of the science concepts. They also had difficulties in expressing the analogy because they lacked the expressiveness of analogy or abilities in mapping errors. They had difficulties in expressing the planned role-playing analogy in a narrow space. Second, students also experienced difficulties in performing activities due to lack of understanding on activities or lack of experience. Third, students experienced difficulties in selecting roles because they preferred the specific role or unwanted the specific roles. Fourth, the members of group experienced difficulties in group activities because they did not concentrate on activities, failed to perform roles, or showed attitudes of an onlooker. Fifth, they experienced difficulties in communications due to unilateral communication, conflicts of opinions, and lack of opinions.