• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.11
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• pp.2073-2082
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• 2010

The 4-th generation of mobile communication aims to realize global, fast and mobile communication service. The satellite communication charges a key role in this field. In this study, an OTM(On-The-Move) antenna which is mounted on ground vehicles and is used for mobile communication between vehicle and satellite was addressed. Since vehicles move during communication, active antenna line-of-sight stabilization is a core technology to guarantee high satellite communication quality. Stabilization of a satellite tracking antenna which consists of 2-DOF gimbals, an elevation gimbal over an azimuth gimbal, was considered in this study. Various disturbance torques such as static and dynamic mass imbalance torques, variation of moment of inertia according to elevation angle, friction torque related to vehicle motion, equivalent disturbance torque due to antenna roll motion, etc. were analyzed. As a robust stabilization control, rate feedback with sliding mode control and position feedback with proportional+integral control was suggested. To compensate antenna roll motion, a supplementary roll rate feed forward control was included beside of the feedback control loop. The feasibility of the analysis and the proposed control design were verified along with some simulation results.

• Architectural research
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• v.7 no.2
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• pp.35-45
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• 2005

This study discusses "mechanisms" in a research facility, specifically focusing on the question of how we can understand what happens in the physical environment and the communication between researchers. This study attempts to address this question by examining two physical settings, before and after the move of one research-educational facility, the Institute of Paper Science and Technology. The objective of the study is to suggest conceptual models to comprehend the relationships between spatial layouts and communication. The study examines the underlying mechanism of how the levels of communication meet the layers of spatial structure. The paper has four parts. First, the preceding studies will be reviewed evoking some issues of communication and physical setting in research facilities. Second a conceptual typology in office plan will be developed providing a theoretical framework to review the spatial organization of the subject research facility, the Institute of Paper Science and Technology (IPST). Third, the spatial organization of the former building (before the move) and the present building (after the move) of IPST will be analyzed. Finally, conceptual models of the mechanism between the communication and the spatial organization will be drawn up.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.579-580
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• 2010

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.2
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• pp.158-164
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• 2015

The main mission of OTM(On-The-Move) satellite communication system is to provide satellite communication service while moving on a vehicle. So it should have a capability to maintain a reliable communication channel when it travels at high speeds or in a severe fluctuation region. This paper presents a small-sized multi-mode monopulse structure applicable to OTM satellite communication system which has only single mode-coupler with a pair of slot using a feature of circular polarized received signal. And tracking error signal is defined using fundamental and high-order modes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.9
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• pp.757-766
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• 2014

To compensate signal loss due to the channel blockage in satellite communication link, we propose a cooperative communication scheme for OTM(On-The-Move) terminal in next generation satellite communication systems. The proposed scheme configures cooperation subnet with adjacent OTM terminal with the help of ground communication equipment. Shared data is spread by orthogonal spreading code, then the spread sequences are transmitted simultaneously. The receiver combines the power of received signals by EGC(Equal gain combining). The OTM terminal blockage channel is modeled by 2-state Markov chain. We evaluate the bit error rate according to the blockage channel of the channel state for the performance analysis of the proposed scheme. As a result, the proposed scheme shows better BER performance than traditional scheme with the help of subset members. In particular, the proposed scheme shows superior performance as the channel block probability is higher. However, as the number of subset members is increasing, there is a constraint because of the higher multiple access interference.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.10
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• pp.951-959
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• 2011

In this study, an OTM(on-the-move) antenna which is mounted on ground vehicles and is used for mobile communication between vehicle and satellite while moving was addressed. Since LOS(line-of-sight) of antenna should direct satellite consistently while vehicle moving to guarantee high satellite communication quality, active antenna LOS stabilization is a core technology for OTM antenna. Stabilization of a satellite tracking antenna which consists of 2-DOF gimbals, an elevation gimbal over an azimuth gimbal, was considered in this study. In consideration of driving mechanism which consists of gear train and flexible driving shafts, a two-mass-system dynamic model coupled with vehicle motion was presented. An internal PI-control loop + outer PI-control loop structure has been suggested in order to damp the torsional vibration and stabilize control system. The classical pole-placement method was applied to design control gains. In addition, a vehicle motion compensation control beside of the feedback control loop has been suggested to improve LOS stabilization performances. The feasibility of the proposed control design was verified along with some experimental results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.1
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• pp.1-8
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• 2015

In this paper, a double-input single-output architecture of a LNA(Low Noise Amplifier) is presented to enable to be devised for light weight and small-sized OTM(On-The-Move) satellite communication system suitable to be mounted on vehicles. In spite of advantages of the double-input single-output architecture of a LNA such as reduction of the number of physical channels, it results in time-varying phase error between a fundamental mode path and a high-order mode path. This paper shows that the error can be corrected by adding pilot signals to the LNA and using signal processing, and also gives the measurement data to use the method mentioned above.

• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.3
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• pp.143-152
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• 2008

This thesis is what accident in sea have been produced as lost themselves life and property about 600~700times at every years. Therefore this was induced to experiment on a national basis that the role of communication of ship is to move from lose themselves life and property.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.2
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• pp.223-234
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• 2014

This paper describes the analysis results of channel characteristics in the operating area of satellite OTM(On-The-Move) terminal. The communication channel between the Koreasat-5 and OTM terminal on a test car is measured and recorded from Daejeon to Daecheon, using the downlink frequency of around 20 GHz. And the measurement data are divided into two classes ; highway environment and national road environment, and then are statistically analyzed. The statistical evaluation of satellite channel is conducted by using probability density function and Markov model and then presents average connection duration(ACD), average fade duration( AFD), and level crossing rate(LCR) of highway environment and national road environment. Finally the statistics data of the two environments are compared with each other.

• Journal of the Korean housing association
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• v.18 no.4
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• pp.37-48
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• 2007

Purpose of this study is to investigate influence on preference of cohousing (eg. intention to spread and intention to move in cohousing) according to sense of community, especially in housing life by married people residing in Seoul and its outskirts. Research method used for this study was a social survey. Respondents were 214 people by accidential sampling. The collected data were analyzed by SPSS 12.0 program using frequency, mean, average, T-test, one-way Anova, Duncan's Multiple Range test and Chi-square test. Findings of this study were as follows. Most respondents took part in interactive activities with colleagues from the same occupation. They Focused on the issues about health, leisure and hobby. The respondents mainly wanted to have interaction for changing recycling materials and education programs for children and juveniles. Degree of ideal relationships with neighbors, they think, were greeting and chatting as well as communication about issues on child-care, education for children, offense-prevention and safety. Although respondents were interested in community life and in interaction with their neighbors, they did not build up communal society due to lack of a sense of belonging in their living areas. While respondents showed positive response about preference of cohousing, there were difference between intention to spread of cohousing and intention to move in cohousing. As a result of this study, the stronger sense of community in housing life meant the more interests in thoughts to spread and to move in cohousing. Therefore, in order to increase sense of community in cohousing, the plan of various communication programs that enables frequent interaction among neighbors is needed. Also, in order to spread cohousing in Korea, promotion of cohousing community and cognitions about it are the most needed.