• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.8
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• pp.797-804
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• 2011

Network coding has recently emerged as an effective solution for multicast and broadcast communications in wireless ad hoc networks. In this paper, we propose a throughput performance model for IEEE 802.11 wireless networks with network coding. Specifically, we consider IEEE 802.11 DCF protocol and linear topology in which traffic sources are located at both ends and intermediate nodes act as relays performing network coding. The proposed analytic model has the form of nonlinear equations in terms of throughput of each node. The solution of the nonliear equations thus correspond to the end-to-end throughput. Extensive simulation experiments have been performed to validate accuracy of the proposed model. Numerical results show that the results of the proposed analytic model agree fairly well with the corresponding simulation results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.7
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• pp.728-736
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• 2014

Due to the recent development of mobile wireless telecommunication, RRHs(Remote Radio Heads) are widely being utilized to expand the cell coverage. Wire-link, an existing connection between DU(Digital Unit) and RRH through fiber cables, is considered to have limitations in relation to cost for a wide range of applications. This paper focuses on replacing the wire-link by wireless transmission using millimeter-wave, and implementing cellular network system through RRH from a remote location. After an influence element analysis on millimeter-wave wireless link transmissions, a comparative analysis between wireless link and an existing fiber link method will be made by utilizing currently commercialized LTE(Long Term Evolution), to prove the compatibility of millimeter-wave wireless link RRH method in replacing fiber link method without a significant decline in data transmission performance.

• Journal of Advanced Navigation Technology
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• v.18 no.6
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• pp.541-545
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• 2014

Rec. ITU-R M.1842-1 is international recommendation for VHF band communication guideline in maritime mobile service RR Appendix 18 channels. In this paper, we simulate 28.8 kbps VHF ${\pi}$/4-DQPSK digital baseband modem compatible with the recommendation, then it is designed and implemented with FPGA. Cazac sequence is used as a preamble since packet format is not defined untill now in the recommendation. Baseband modem is designed by VHDL language and implemented on NEXYS4 development platform having Atrix7 FPGA chip from Xilinx. For wireless communication test of total prototype system, ADC/DAC board is implemented and EV9730 RF module is utilized. From the experimental results, implemented FPGA modem shows spectral bandwidth of 25 kHz and successful data exchanges between tx and rx communication platform.

• Informatization Policy
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• v.17 no.2
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• pp.86-103
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• 2010

This paper computes the economic impact of handset subsidies using the recent Input-Output Tables and compares the results with other alternatives which telecommunications companies can choose. The first scenario is that telecommunications companies give handset subsidies to consumers and sales agents. The second is that the companies do not give the subsidies to them, but instead spend the same amount of subsidy on facility investment. The third is that the companies lower the prices of their mobile communications services and consumers spend the saved expenses on other goods and services. The result is that the production, value added, import, job, employment inducement coefficients of the first scenario is larger than those of the second and third scenarios. The reason is as follows. The handset subsidy results in the incentive to consumers for handset purchase or the incentive for sales agents to sell the telecommunication services of the companies. The former has larger production and import inducement effect, and the latter also has larger value-added, job, and employment inducement effect than those of other scenarios.

• Smart Media Journal
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• v.5 no.4
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• pp.90-95
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• 2016

Recently, the quality of cultural experience can be improved through a stereoscopic information service provided by the latest mobile-based Information Telecommunication technology without the human cultural commentators, which was used in order to enhance the understanding of our cultural heritage. The purpose of this paper is to produce contents that introduce cultural heritage using the Android-based GPS and augmented reality. In this paper we propose a culture content creation method that is based on location information such as user/cultural anomalies using GPS and augmented reality based on Markerless Tracking. Marker Detection Technology and Markerless Tracking Technology are used for smart phone's rapid recognition of augmented real world and accurate recognition according to the state of the cultural heritage. Also, the Google Map of Android is used to locate the user. The strength of this method lies in that it can be used for a variety of subjects while the existing methods are limited to certain kinds of augmented reality contents.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.1589-1594
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• 2013

V.M.D(Visual Merchandising Design) covers every space, environment, and visually stimulating factor. This includes not only the architectural appearance but interior, graphic sign boards, window display, layout, store appliances, lighting, and even the looks and service attitude that sales employees have and show to customers. V.M.D aims to display merchandise in multiple ways; to heighten brand images; to steadily lure many customers to the store. One of the characteristics that V.M.D has is, that this abandons the previous design concept which solely puts stress on luxurious interior-focused display; that this displays merchandise in a rational and systemic way and induces customers to buy products. In this regard, the objective of this study is to study brand perception and effect of V.M.D displayed in the stores, on customers, and thereby to present the concepts of V.M.D, suitable for display in the stores, which can be used continuously in the future.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.8B
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• pp.569-580
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• 2005

In case of one of the next generation mobile telecommunication; WCDMA service, the relevant market growth is delayed by market uncertainty, lack of effective demands, rapid evolution of technology, non-existence of business strategy, lack of distinction with competitive services and killer applications. In this study we intended to analyze the influence factors of market diffusion and marketing strategy of WCDMA. For doing so, we obtained both promotion and hindrance factors for diffusing the market of WCDMA through expert survey. Also we acquired such categories as factor for adoption, willingness to pay, killer application, preferred terminal and pronising customer, which becomes the reason ifluencing on the decision of WCDMA service marketing strategy. On the basis of such results, this paper suggests the direction of deployment for marketing focusing on the strategies as customer, price, sewice, terminal provision, and positioning of WCDMA.

• The Journal of the Korea Contents Association
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• v.4 no.2
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• pp.21-27
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• 2004

In an urban area telecommunication using wireless system, the accurate prediction and analysis of wave propagation characteristics are very important to determine the service area optimized selection of base station, and eel design, etc. In the stage of these analyses, we have to present the propagation prediction mood which is varied with the type of antenna, directional angle, and configuration of the ground in our urban area in addition we need to perform an analysis of the conventional mode which is similar to ours and dig out the parameters to evaluate the wave environment before the cell design for the selected area. In this paper, we propose a wave propagation prediction model concerning the topography and obstacles in our urban area. We extract the parameters and apply them to the proposed wave environment for the simulation analyzing the propagation characteristics. Throughout these analyzing procedure, we extracted the essential parameters such as the position of the base station, the height of topography, and adequate type and height of the antenna with our preferable cuteness.

• Journal of the Korean Society for Railway
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• v.16 no.6
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• pp.540-550
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• 2013

The Future Wireless Railway Communication System(FWRCS) has attracted attention for the various advantages of such a system like efficient management, precise periodicity of operation and speedy travel. Related to it, the area of bandwidth requirement estimation for the FWRCS is being researched actively because there is a great need for accurate bandwidth distribution. In this paper, sophisticated bandwidth requirement estimation method for FWRCS is proposed by modifying ITU-R M.1390. With this method, the expected frequency requirements for the present, for five years from now, and for 10 years from now can be calculated by applying the data gathered from the actual field.

• Journal of Digital Convergence
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• v.10 no.4
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• pp.55-62
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• 2012

This paper analyze the DEA(Data Envelopment Analysis) efficiency of government budget to HRD program(ITRC) and correlation and regression between its inputs and outputs in the field of information technology. First, empirical results show that the relationship between the supporting period of government budget and scientific research & HRD outputs is respectively irrelevant. Second, another finding is that the relationship between government budget and HRD output is positive. Finally, DEA efficiency analysis implicates that SW/digital contents, digital TV, information security, intelligence robot, next generation PC, next generation mobile telecommunication, home network, mathematics, IT SoC are more efficient than any other technology fields.