• Journal of Advanced Navigation Technology
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• v.15 no.4
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• pp.562-570
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• 2011

In this paper, a distributed mobile relay power control (DMRPC) scheme for maximizing individual cell throughput is proposed for mobile relay aided multi-cell orthogonal frequency division multiplexing (OFDM)-time division duplex (TDD) system. In the system with DMRPC, the power levels of relay's are controlled by individual cell without cell cooperation and signalling overhead. It is demonstrated by numerical simulation that DMRPC provides the better cell throughput performance than either the full power relay aided system or conventional system without relay does. Moreover, it is also shown that relay aided systems with DMRPC, and the conventional system have almost identical cell edge throughput, while full power relay aided systems show worse performance in cell edge throughput.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.191-197
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• 2013

Recently, the demand for mobile systems is remarkably growing due to the explosive spread of smart phones. The mobile system based on the smart phones enables the real time communication and business process by utilizing the on-line information on the spot anytime and anywhere. This paper proposes a development model to use android-based mobile applications to be applicable to the facility defect maintenance management in apartment buildings. The proposed methodology aims to implement an incorporated system to bind the web-based system and the mobile system in systematic interaction in order to feasibly realize the concept of mobile office.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.1
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• pp.39-50
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• 2010

In this paper, we analyze and simulate the performance of a tactics mobile communication system based on ultra wide band (UWB) in multi-user interference (MUI) environments. This system adopts a double binary turbo code for forward error correction (FEC). Wireless channel is modeled a modified Saleh and Valenzuela (SV) model. We employ a space time block coding (STBC) scheme for enhancing system performance. System performance is evaluated in terms of bit error probability. From the simulation results, it is confirmed that the tactics mobile communication system based on UWB, which is encoded with the double binary turbo code, can achieve a remarkable coding gain with reasonable encoding and decoding complexity in multi-user interference environments. It is also known that the bit error probability performance of the tactics mobile communication system based on UWB can be substantially improved by increasing the number of iterations in the decoding process for a fixed cod rate. Besides, we can demonstrate that the double binary turbo coding scheme is very effective for increasing the number of simultaneous users for a given bit error probability requirement.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.266-266
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• 2000

This paper relates to develop the human-mobile interface system using saccadic eye movements as an aid to the disabled. EOG(ElectroOculoGraphy) method is used to measure the potentials of rapid eye movements because the method is not expensive and the device is simple. But because the resolution and accuracy of this signal are not good, the algorithm to remove the drifting, using ideal velocity shape, is applied to process the signals. The mobile robot (POSTUR-II) used in this system was developed in Robot & Bio-mechatronics laboratory in POSTECH and has the tele-operation system for the tele-communication with a main computer. Our Research is to help the physically disabled except his eye movements to operate some works with the mobile. Our Results about the system's possibility will be showed by some experimental tests giving the point information to the mobile by eye-gaze.

• Journal of Information Technology Services
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• v.11 no.2
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• pp.339-353
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• 2012

Mobile communication technology is advancing forward to deliver more connected devices and richer content and applications. The number of subscriptions continues to grow along with an explosive increase in the mobile data traffic demand. Thereby, it creates a significant network capacity shortage concerns for mobile network operators. In order to address this problem, it is essential to increase the network capacity at a low additional cost. The device-to-device (D2D) communication based proximity service is believed to have a promising future mobile communication technology that is capable to create new mobile service opportunities and offload traffic to the eNB. In addition, it is also required to develop new mobile communication services and its business models not only to accommodate the increasing mobile traffic demand but also to foster profitability of mobile business service providers such as the network providers, contents providers and platform providers. In this article, we first analyze current mobile business eco-system in the context of CPNT based value chain. Then, propose service development framework and business model creation methodologies for the device-to-device communication based services in the beyond LTE/LTE-Advanced systems.

• Journal of Korea Multimedia Society
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• v.17 no.12
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• pp.1473-1483
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• 2014

A public restroom is different from a household toilet in terms of location and a large number of sharing users. In addition, public restroom is usually messy and filthy. Recently, public toilet tends to be clearly managed than before, but it still has hygienic and clear problems. In this paper, we propose a machine-to-machine (M2M)-based public restroom management system to solve these problems, in which the system with a wireless communication device sends the status information of the toilet, such as blockage or trouble detected by a sensor, to the manager of the restroom at a remote location. In particular, we have developed a prototype management system for public restroom taking into account several system requirements, and verified the basic operations and performance of the management system. With the application of the system to public facilities, it will furnish users with more pleasant environments by restroom administrators who can respond effectively to the troubled toilet.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.3 no.1
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• pp.35-39
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• 1978

Present system of maritime mobile communication is depend upon HF Band mostly. Due to the range of technical development activities for HF Band has reached to uppermost limit, it is going to be hard to meet the requirements of communication which would be increased in the future, by utilization of HF Band. Studying difficulties of realizing communication function and the uppermost limit of HF Band system, in order to seek more smooth communications under present system, I have been studying remedy of problems in using of HF Band system with examples of relay of free-charge telegrams for the group of an ocean-going vessels of our country, and analized and studied of future prospects of maritime mobile communication.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11
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• pp.2845-2862
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• 1999

As the technical advances in portable computers and wireless communication technologies, mobile computing environment has been rapidly expanded. The mobile users on mobile host can access information via wireless communication from the distributed heterogeneous multidatabase system in which pre-existing independent local information systems are integrated into one logical system to support mobile applications. Hence, mobile transaction model should include not only the features for heterogeneous multidatabase systems but also the ones for mobile computing environment. In this paper, we proposed a mobile flex transaction model which extends the flexible transaction model that previously proposed for heterogeneous multidatabase systems is extended to support the requirements of mobile heterogeneous multidatabase systems. We also presented the execution control mechanism of the mobile flex transaction model. The proposed mobile flex transaction model allows the definition of location-dependent subtransactions, the effective support of hand-over, and the flexibility of transaction executions. Hence, the proposed mobile flex transaction model can be suit to mobile heterogeneous multidatabase systems that have low power capability, low bandwidth, and high communication failure possibility.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2117-2123
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• 2014

To cope with the explosive growth of traffic which is considered as one of the most biggest threat to current mobile communication systems, various solutions such as small cell and device-to-device communication have been exploited. Directional transmission in which transmission power of base station is focused onto the direction where the mobile station is located, can be used to increase throughput of the system. In this work, we develop a system-level simulator for cellular mobile communication systems using directional transmission and adaptive interference estimation scheme for directional transmission has been proposed. By using the developed simulator, the performance of cellular mobile communication systems with directional transmission is examined. Moreover, it is shown that the overall throughput of cellular system can be improved by utilizing directional transmission.

• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.2
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• pp.101-105
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• 2008

We applied web-standard technologies like XHTML CSS etc. to Mobile Tide Forecasting System. Through mobile hot key(659+hot key), users can connect the system and get conveniently the tide forecasting information in mobile communication environment.