• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.3
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• pp.134-148
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• 2007

There is not enough knowledge on how to use, build, and apply ubiquitous technologies such as the ubiquitous sensor network, GIS, statistic analysis system, mobile GPS system etc. Also there are other questions such as, how should the knowledge information resources be managed and web decision making system developed for national park management. The purpose of this study is to propose a framework for the national park integrated management system based on ubiquitous information technology. This study will include followings: 1) this study explores what ubiquitous information technologies are needed for national park management, 2) this study proposes building strategies about the spatial and attribute database using ubiquitous information technologies, and links methods among geographic information system, analysis program, sensor network, etc. The results of this study will contribute towards deciding a direction for national park policy in preparation for the ubiquitous computing oriented society.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.2
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• pp.243-251
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• 2010

The military has been putting great efforts into applying data communication on existing voice communication systems being used in NCW(Network Centric Warfare). Data communication will be an effective choice in one of many effort to yield a minimum kill chain, comparing to legacy voice communications, when tactical units conduct their missions. However, the required budget will be enormous, in case of the replacement of a lot of legacy communication systems with new one. As a cost-effective alternative, the tactical data communication systems using the conventional radio systems instead of the development of new radio systems has been proposed. It is mandatory, though, to ensure QoS while maintaining data communication by making use of legacy radio systems already in use. This paper focuses on the performance issues experimented and analyzed for tactical data communication through the legacy radio systems as the first step towards guaranteed QoS. We have conducted various experiments such as the transmission error rate on certain tactical messages, performance evaluation of redundant transfers, the relationship between the transmission frame size and rate of error, the identification of error points in the transmission frame, and techniques to reduce the errors in both hopping and non-hopping modes. As a result of the performance experiments, The adaptive communication module which decides the redundant transmission or the Forward Error Correction(FEC) technique by analyzing channel status and current transmission status(hopping/non-hopping) of the legacy radio should be designed. the FEC technique in non-hopping, and the redundant transmission technique in hopping mode was recommended from the result of experiment with the frame size is 20bytes in non-hopping and 10Bytes frame size in hopping mode.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.10
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• pp.1181-1188
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• 2007

This paper presents the measured signal performances in the urban environment for the DVB-H parameters such as code rate, burst size, FFT mode and modulation technique to analyze the DVB-H signal performance avaible for the embodiment of single frequency network to improve the frequency efficiency. Measurements were performed for the case for applying and non-applying MPE-FEC technique simultaneously. Results show that the most outstanding performance are found in the case of QPSK modulation, 1/2 code rate, 2 k FFT mode and 512 burst size. In addition, the signal performance by the SFN with 1/8 guard interval becomes superiour in comparision with the measured data from each site and the data from SFN with 1/32 guard interval. The analysis of the results can be instructive for the improvement of the signal performance and broadcasting quality for the terrestrial digital mobile broadcasting service.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.2
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• pp.109-115
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• 2011

As fingerprinting method, k-nearest neighbor(KNN) has been widely applied for indoor location in wireless location area networks(WLAN), but its performance is sensitive to number of neighbors k and positions of reference points(RPs). So artificial neural network(ANN) clustering algorithm is applied to improve KNN, which is the KNN/ANN hybrid algorithm presented in this paper. For any pattern matching based algorithm in WLAN environment, the characteristics of signal to noise ratio(SNR) to multiple access points(APs) are utilized to establish database in the training phase, and in the estimation phase, the actual two dimensional coordinates of mobile unit(MU) are estimated based on the comparison between the new recorded SNR and fingerprints stored in database. In the proposed algorithm, through KNN, k RPs are firstly chosen as the data samples of ANN based on SNR. Then, the k RPs are classified into different clusters through ANN based on SNR. Experimental results indicate that the proposed KNN/ANN hybrid algorithm generally outperforms KNN algorithm when the locations error is less than 2m.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.73-80
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• 2008

The recent trend in home network system includes intelligent home environments that remote monitoring and control service is achieved without restrictions by device types, time, and place. Also the use of a vacuum robot in homes is gradually generalized on account of the convenience of the use. In this paper, we proposed and realized new home-monitoring system with the employment of an self-movement robot as one trial for realizing an intelligent home under home network environment. The proposed system can freely monitor every where in home, because the system effectively overcame the surveillance limitations of the existing monitoring system by attaching a Wireless Router and WebCam to a commercial vacuum robot. The outdoor users of this system can readily monitor any place which they want to supervise by controlling a vacuum robot with mobile telecommunication devices such as PDA. The wireless router installed with Linux operation system "OpenWrt" made it possible for the system users to transmit images and to control a vacuum robot with RS-232 communication.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.151-155
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• 2017

With the rapid growth of the up-to-date wireless network and Internet technologies, huge and various types of things around us are connected to the Internet and build the hyper-connected society, and lots of smart applications using these technologies are actively developed recently. IoT connects human, things, space, and data with various types of networks to construct the hyper-connected network that can create, collect, share and appling realtime information. Furthermore, most of the smart applications are concentrated on the service that can collect and store realtime contexts using various sensors and cloud technology, and provide intelligence by making inferences and decisions from them nowadays. In this paper, we design a smart application that can accurately control and process the current state of the specific context in realtime by using the state-of-the-art ICT techniques such as various sensors and cloud technologies on the IoT based mobile computing environment.

• Journal of Advanced Navigation Technology
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• v.15 no.4
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• pp.585-590
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• 2011

In the past few years, M2M (Machine-to-Machine) applications have become a hot topic in the wireless industry. While M2M applications can be used for many purposes (smart homes, smart metering/electricity meter reading, fleet management, mobile workforce, automobile insurance, vending machines, etc), and in many sectors (healthcare, agriculture, commercial, industrial, retail, utility, etc.), smart metering applications or smart grids present the biggest growth potential in the M2M market today. M2M platform is the future ubiquitous network technologies which provide the integrated service with the networks and devices. The promising technologies to tackle these problems are the Semantic technologies, for interoperability, and the Agent technologies for management of complex systems. In this paper the information communication technique based on the disaster prevention system's for the M2M, concepts and its requirement technology and application are studied.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.1B
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• pp.21-28
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• 2011

The femtocell is a miniaturized Base Station (BS) with low-cost and low-power using general broadband access network as backhaul. It is expected not only to improve indoor coverage but also to reduce a service charge. However, in IEEE 802,16e femtocells, when the Mobile Station (MS) scans neighbor BSs for handover, it takes a long time due to too many number of femto BSs. Also the size of the neighbor advertisement message that will be periodically sent by a serving BS is increased as the number of target femto BSs for scanning increases. In this paper, we proposed an efficient femtocell scanning scheme, using a triangulation mechanism and a femto BS monitoring scheme to reduce the number of scanning operations and the size of the neighbor advertisement messages. The proposed scheme can avoid wasting air resources and reduce scanning overheads by minimal scanning operation. The simulation results showed that the proposed scheme could improve scanning performance and avoid wasting air resources, compared with the conventional scheme of the IEEE 802.16e system.

• The Journal of the Korea Contents Association
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• v.9 no.3
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• pp.99-107
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• 2009

As the information and the network technology are improved, the system which can express the interactions between the individuals becomes to play more important roles in these days. In fact, that tendency is especially well shown in the community area of P2P and social network service programs. This paper suggest an intelligent character manipulation system which can be effectively used to express emotional representation in an intelligent way in spite of many constraints. The system employs an emotion searching mechanism by attaching emotional information to each object in the database and defining a function of emotional similarity. It is expected that the system can be successfully used not only to find and represent the suitable emotional character representations but also to provide brand new services in the area of mobile platform based contents.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.12
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• pp.2272-2293
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• 2011

Communication technology of future networks is predicted to provide a large variety of services including WiFi service in vehicular network. In this paper, we assume that vehicles are embedded with WiMAX antenna and in-vehicle terminals receive WiMAX traffic through WiFi interface. This assumption will impose severe performance degradation due to interference among mobile BSSs when WiFi access points (APs) are densely located. Existing interference avoidance techniques cannot properly resolve the above problems and do not cope with dynamically moving vehicular scenario since they focus only on the fixed network topology. In this paper, we propose a mobility-aware interference avoidance scheme for WiFi services. The proposed scheme computes the interference duration by exploiting mobility vector and location information of neighboring APs. If the interference duration is not negligible, our scheme searches for another channel in order to avoid interference. However, if the interference duration is negligible, our scheme continues to use the channel to reduce switching overhead. To measure the effectiveness of the proposed scheme against other existing techniques, we evaluated performance by using OPNET simulator. Through the simulation, we obtained about 60% reduction in the maximum interference frequency and about 67% improvement in throughput. Furthermore, our scheme provides fair channel usage.