• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.3
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• pp.242-248
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• 2017

Recently, Population has been concentrated in cities due to rapid economic growth. As a result, urban buildings are becoming more dense, high-rise, and diversified. The shape of these urban buildings increases the risk of fire, accidents and crime. The narrow living space has the characteristic of the unchanged floor. In case of a fire, the living space of the narrow residence is large in the damage because the smoke diffusion rate is fast. The radio wave transmittance and transmission distance of wireless communication used in fire fighting operations vary depending on the type of building materials and buildings. Therefore, this paper analyzes the building materials and structural characteristics of the narrow residential space for efficient fire fighting operations. We have developed a communication environment solution for a narrow residential space for the optimal fire fighting operation through the measurement of the radio wave transmittance and the transmission distance of the wireless communication.

• Korean Institute of Interior Design Journal
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• v.19 no.4
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• pp.22-30
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• 2010

Light has primary function to enlighten the darkness. However, as development and progresses in media has caused big change in our life, the range of usage and application of light is broadened. And these days, light is actively used as a communication tool in a space. This thesis is based on an idea that a new prospect of light is required and at the same time the theoretical foundation should be established to take active advantage of light. In Chapter two, analysis criteria are established to verify study hypothesis. The applied methodology is to analysis the contents based on literature review. Key words related light in space design are extracted and the frequency of those key words are quantitatively measured. Taking advantage of the result, the characteristics of light are divided into three categories, 'light as symbolic information', 'light as communication medium' and 'light as topological form'. In chapter three, analysis of cases is performed. The cases are selected based on space analyzing criteria established in Chapter two. Qualitative analysis is performed on the cases categorized into natural light and artificial light. Basic analysis elements are evaluated for each case. And each case is allocated to one of three categories, 'light as symbolic information', 'light as communication medium' and 'light as topological form'. Through this analysis, it is found that light in space has prevailing characteristics of 'light as symbolic information' and 'light as communication medium'.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.2
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• pp.670-683
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• 2016

Network coding, as a new technique to improve the throughput, is studied combined with multi-relay model in this paper to address the challenges of long distance and power limit in deep space communication. First, an amplify-and-forward relaying approach based on analog network coding (AFNC) is proposed in multi-relay network to improve the capacity for deep space communication system, where multiple relays are introduced to overcome the long distance link loss. The design of amplification coefficients is mathematically formulated as the optimization problem of maximizing SNR under sum-power constraint over relays. Then for a dual-hop relay network with a single source, the optimal amplification coefficients are derived when the multiple relays introduce non-coherent noise. Through theoretic analysis and simulation, it is shown that our approach can achieve the maximum transmission rate and perform better over single link transmission for deep space communication.

• Journal of the Optical Society of Korea
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• v.19 no.1
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• pp.45-54
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• 2015

In this study, a novel parallel wavefront correction system architecture is proposed, and a model-based tabu search (MBTS) algorithm is introduced for this new system to compensate wavefront aberration caused by atmospheric turbulence in a free-space optical (FSO) communication system. The algorithm flowchart is presented, and a simple hypothetical design for the parallel correction system with multiple adaptive optical (AO) subsystems is given. The simulated performance of MBTS for an AO-FSO system is analyzed. The results indicate that the proposed algorithm offers better performance in wavefront aberration compensation, coupling efficiency, and convergence speed than a stochastic parallel gradient descent (SPGD) algorithm.

• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.13-21
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• 2016

Since the direct-gradient (DG) method uses the Shack-Hartmann wave front sensor (SH-WFS), based on the phase-conjugation principle, for atmospheric compensation in free-space optical (FSO) communication, it cannot effectively correct high-order aberrations. While the stochastic parallel gradient descent (SPGD) can compensate the distorted wave front, it requires more calculations, which is sometimes undesirable for an FSO system. A hybrid compensation (HC) method is proposed by properly using the DG method and SPGD algorithm to improve the performance of FSO communication. Simulations show that this method can well compensate wave-front aberrations and upgrade the coupling efficiency with few computations, preferable correction results, and rapid convergence rate.

• Educational Technology International
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• v.8 no.2
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• pp.113-140
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• 2007

This study purports to contribute in deepening our understanding of ISD (instructional systems design/development) from Edward Hall's concept of intercultural communication. Renowned anthropologist Edward Hall introduced three concepts of cultural differences: time, space, and context. This paper explores how theses cultural dimensions - time, space and context- are reflected in ISD and compares the cultural differences between the east and the west that emerge in the process of applying ISD.

• Bulletin of the Korean Space Science Society
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• 2006.04a
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• pp.78-78
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• 2006

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.95-95
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• 2004

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.1
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• pp.69-75
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• 2011

As part of its space development program, Korea has a plan for the launch of a lunar orbiter and a lunar lander. To enable the transmission of lunar information based on multimedia, it is necessary to construct a communication system that is capable of transmitting large-volume telemetry data. The CCSDS standard recommends the deferred NAK mode as ARQ scheme for reliable long-distance deep-space communication systems. In this paper, we implement a space communication system simulator in the deferred NAK mode using models of the lunar orbiter, the earth station, and the space environment. The simulator employs modulation techniques and turbo coding schemes for transmitting large-volume telemetry data. We analyze the transmission performance of telemetry data through the simulation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.6
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• pp.2606-2626
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• 2016

This article investigates the distributed data storage problem in the space information network (SIN) using distributed fountain codes. Since space nodes in the SIN are resource-limited, in order to reduce energy consumption while improving the storage reliability, an efficient distributed storage based on fountain codes and probabilistic broadcasting (DSFPB) strategy is proposed. In the proposed strategy, source packets are disseminated among the entire network according to probabilistic broadcasting (PBcast), and the final degree distribution is close to the desired robust soliton distribution (RSD), this is benefited from the appropriate packets encoding procedure of the proposed strategy. As presented by the analysis and simulations, the total cost of data dissemination is greatly reduced compared with existing representative strategies, while improving the decoding performance.