• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.537-542
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• 1996

ITU-T에서 표준 비디오 코딩 알고리즘으로 채택한 MPEG 코딩방식은 세 가지의 코딩방식 (I,B,P,방식)을 주기적으로 사용하기 때문에, 코딩된 정보량에 강한 주기성을 보인다. 본 연구에서는 이러한 MPEG 비디오 트래픽의 주기성을 반영하는 개별 비디오 원의 트래픽을 모형화하고 이를 바탕으로 다중화 장치의 성능분석을 실시하였다. 개별 비디오 원에서 발생된 트래픽은 I, B, P의 코딩순서를 반영하고, I, B, P 프레임 별로 셀 수를 모형화 하였다. 그리고 다중화 장치에 입력되는 트래픽은 프레임 시간 단위로 이산화시켜 셀 수를 모형화하였고, 이를 이산시간 마코프 연쇄를 이용해 다중화 장치에서의 셀 손실률을 구하였다. 다중화 장치에서 셀 손실은 입력되는 잘대적인 트래픽의 양 뿐만 아니라, 비디오 원 정렬 (Source Alignment)에도 많은 영향을 받는다. 이러한 비디오 원의 정렬 효과를 반영하여 다중화 장치에 연결될 수 있는 비디오 원의 수를 결정하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.9
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• pp.739-744
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• 2014

Space exploration project usually consists of so many fields of sub projects that it has a diverse ripple effect throughout the economy. Further studies could not consider the complexity of the space exploration project because they regarded it as one project in spite of the diversity. This study found a way to consider complexity of space exploration project using the concept of WAC(weighted average coefficient). The moon exploration project (2014~2020) is the subject of this study. We classified the moon exploration project into 8 industries and calculated the WAC of production inducement coefficient, value added inducement coefficient, and employment inducement coefficient. The result of analysis using these WACs is that production inducement effect amounts to 1,229.6 billion won, value added inducement effect 324.6 billion won, employment inducement effect 4,844 men. And the linkage effect analysis shows that moon exploration project has more backward linkage effect than forward linkage effect.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.51-53
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• 2015

In this paper, we propose a new relay selection technique which utilizes interference cancellation with decoding information at multiple relays for buffer-aided successive relaying systems. The transmitting relay is selected if its own transmission to the destination is successful and the number of relays which can successfully decode the data from the source is the maximum at the same time. Simulation results show that the proposed relay selection technique significantly outperforms the conventional relay selection scheme in terms of outage probability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12A
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• pp.1960-1965
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• 1999

In this paper, we propose a new method of erased concatenated code with RS-convolutional code. In the method, we make use of erasure for undecoded information when we have some errors in RS decoding. For decoding with erasure, the method is processed inner decoding and outer decoding again. After the erasure decoding, if the decoding result is better than the previous one, then we use this result. If not, use the previous one. In this paper, we use concatenated RS(63,31)-convolutional(4.1/2) code. Simulation result is compared with calculation result for performance analysis. According to the result, the proposed method has better performance than the others without erasure such that 2dB when 0.5$\leq\rho\leq$1 and 4dB when $\rho\leq$0.3.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.56-58
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• 2008

고속 자동 재폐로 방식은 고장 구간의 신속한 자동 복구로 전력계통의 안정도 및 신뢰도를 향상시킬 수 있으나 재계로 실패시 고장 발생 및 차단 순간의 충격과 재폐로에 의한 충격이 연쇄적으로 발전기 회전측에 작용하므로 매우 른 비틀림 충격이 발생 수 있다. 본 논문에서는 발전기 인출단 대용량 송전선로의 재폐로시 발전기 축에 가해지는 충격을 분석하기 위해 EMTP-RV를 이용하여 765kV 송전선로에 연결된 4기의 발전기를 다중 질량제로 모델링하고, 인출 선로 고장 및 재래로 방식에 따른 발전기 축 비틀림 토크를 분석하였다.

• Journal of KIISE
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• v.42 no.6
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• pp.748-754
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• 2015

This paper proposes a sequential state estimation model consisting of continuous and discrete variables, as a way of generalizing all discrete-state factorial HMM, and gives a design of gait motion model based on the idea. The discrete state variable implements a Markov chain that models the gait dynamics, and for each state of the Markov chain, we created a Gaussian process over the space of the continuous variable. The Markov chain controls the switching among Gaussian processes, each of which models the rotation or various views of a gait state. Then a particle filter-based algorithm is presented to give an approximate filtering solution. Given an input vector sequence presented over time, this finds a trajectory that follows a Gaussian process and occasionally switches to another dynamically. Experimental results show that the proposed model can provide a very intuitive interpretation of video-based gait into a sequence of poses and a sequence of posture states.

• Journal of Broadcast Engineering
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• v.15 no.4
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• pp.555-562
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• 2010

After starting digital terrestrial broadcasting, there have been a number oftrials to provide new services like data broadcasting on a spare bandwidth of a DTV channel. Recently, the Push-VOD service, which provides A/V contents on that bandwidth, gets more attention and is being standardized as NRT(Non-Real-Time) by ATSC. However, it is highly probable that the contents transmitted in this way contain many errors due to the DTV receiving environment. Thus, in order to improve the reliability of transmission, the contents should be transmitted repeatedly several times, considering the unidirectional property of DTV terrestrial network. In this paper, we propose a method to calculate the optimal number of repetitions to transmit each contents in a way that minimizes the number of errors occured, when trying to transmit several contents to the receiver in a restricted time, using Markov-chain modeling and dynamic programming approach.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.275-280
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• 2016

In this paper, we propose a novel relay selection technique which utilizes a priori decoding information at relays for buffer-aided successive relaying networks. In the conventional relaying schemes, a single relay pair is selected for receiving data from the source and transmitting data to the destination. In the proposed technique, however, all relays except the relay selected for transmitting data to the destination try to decode the received signal from the source, and they store the data if they succeed decoding. The proposed technique selects the relay such that it can succeed its own transmission and it maximizes the number of relays successfully decoding the data from the source at the same time. It is shown that the proposed relaying technique significantly outperforms the conventional buffer-aided relaying schemes in terms of outage probability through extensive computer simulations.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.3
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• pp.251-258
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• 2010

This paper presents the technology for the design, fabrication, and characterization of a microfluidic system interface (MSI); the purpose of this technology is to enable the integration of complex microfluidic systems. The MSI technology can be applied in a simple manner for realizing complex arrangements of microfluidic interconnects, integrated microvalves for fluid control, and optical windows for on-chip optical processes. A microfluidic system for the preparation of genetic samples was used as the test vehicle to prove the effectiveness of the MSI technology for packaging complex microfluidic systems with multiple functionalities. The miniaturized genetic sample preparation system comprised several functional compartments, including compartments for cell purification, cell separation, cell lysis, solid-phase DNA extraction, polymerase chain reaction, and capillary electrophoresis. Additionally, the functional operation of the solid-phase extraction and PCR thermocycling compartments was demonstrated by using the MSI.

• The Journal of the Acoustical Society of Korea
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• v.15 no.4
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• pp.98-104
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• 1996

This paper propose the alteraton rule to compensate a formant trasition of several connected vowels for improving an unnatural synthesized continuous speech which is concatenated by each demisyllable without coarticulated formant transition for use in dmisyllable based synthesis by rule. To fullfill each formant transition part, the database of 42 stationary vowels which are segmented from the stable part of each vowels is appended to the one of Korean demisyllables, and the resonance circuit used in formant synthesis is employed to change the formant frequency of speech signals. To evaluate the synthesied speech by this rule, we carried out the alteration rule for connected vowels of the synthesized speech based on demisyllable, and compare spectrogram and MOS tested scores with the original and the demisyllable based synthesized speech without this rule. The result shows that this proposed rule can synthesize the more natural speech.