• The Journal of the Acoustical Society of Korea
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• v.26 no.3
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• pp.102-108
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• 2007

A high-Performance scalable speech codec generally requires a very low-rate first layer and a fine granule second layer, and this codec can be implemented with the harmonic codec and the MDCT-based transform codec for each layer. In this structure, however. each codec requires independent frequency transform and the time delay of each codec is accumulated. resulting in long time delay for the overall codec. In this paper, new MDCT structure in the second layer is Proposed. where MDCT is forced to share the look-ahead region of the first layer in order to prevent the time delay accumulation and the resulting functional error of MDCT is analyzed and removed after IMDCT The Proposed delayless MDCT requires no additional bits and Provides the equivalent coding performance with the reduced time delay, yielding a meaningful enhancement of the overall codec.

• Proceedings of the Korean Society of Computer Information Conference
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• 2012.07a
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• pp.297-300
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• 2012

현재 cache의 성능 향상을 위한 많은 기법들이 제안되고 있으며, Latency Hiding 기법 역시 cache의 효율적인 사용을 위해 많은 연구가 진행 되어 왔다. write buffer를 사용한 write Latency hiding기법이나 multi threading을 사용한 Latency Hiding 방법 등 여러 기법들이 연구되어 왔으며, 지금도 Latency hiding을 위한 많은 연구들이 지속적으로 진행되고 있다. 본 논문 역시 효율적인 Latency Hiding을 위한 누적 버퍼를 제안한다. 본 논문은 누적 버퍼의 활용도를 조사하여 얼마나 효율적으로 Latency를 은폐했는지, 또 버퍼를 사용함으로써 얻는 다른 이점에 대해 집중적으로 연구하였다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.4
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• pp.94-104
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• 2008

In this paper, we propose a new architecture of multiplier-and-accumulator (MAC) for high speed multiplication and accumulation arithmetic. By combining multiplication with accumulation and devising a hybrid type of carry save adder (CSA), the performance was improved. Since the accumulator which has the largest delay in MAC was removed and its function was included into CSA, the overall performance becomes to be elevated. The proposed CSA tree uses 1's complement-based radix-2 modified booth algorithm (MBA) and has the modified array for the sign extension in order to increase the bit density of operands. The CSA propagates the carries by the least significant bits of the partial products and generates the least significant bits in advance for decreasing the number of the input bits of the final adder. Also, the proposed MAC accumulates the intermediate results in the type of sum and carry bits not the output of the final adder for improving the performance by optimizing the efficiency of pipeline scheme. The proposed architecture was synthesized with $250{\mu}m,\;180{\mu}m,\;130{\mu}m$ and 90nm standard CMOS library after designing it. We analyzed the results such as hardware resource, delay, and pipeline which are based on the theoretical and experimental estimation. We used Sakurai's alpha power low for the delay modeling. The proposed MAC has the superior properties to the standard design in many ways and its performance is twice as much than the previous research in the similar clock frequency.

• Nuclear Engineering and Technology
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• v.27 no.2
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• pp.226-233
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• 1995

The wall thickness of a pressure tube is increased in order to reduce the probability of failure in a pressure tube of CANDU type reactor. It is presented here that the variation of wall thickness changes stress, hydrogen concentration and delayed hydride cracking in Zr-2.5Nb pressure tube. When the wall thickness is increased from 4.2 mm to 5.2 mm, the stress exerted on the tube and the deuterium taken up during operation are reduced by 19％. Further, the calculated allowable depth of the surface flaw over which delayed hydride cracking(DHC) is susceptible increases by 50％. DHC initiation is controlled by the stress and by the hydrogen concentration in the pressure tube. The results are therefore very significant in such a respect that increased wall thickness may reduce DHC initiation. Ac the wall thickness increases the hydrostatic tension will increase. Its impact on the acceleration of the crack growth rate of DHC deserves further studies.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.548-551
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• 2003

부산 금정산 지역의 지하수위와 강우량과의 관계를 알아보고자 시계열 분석을 통하여 자기상관함수와 상호상관함수를 구하였다. 이를 위하여 금정산 산성마을 주변의 19개 관측공 중 자동수위측정기가 설치된 4개 관측공(KJ2, KJ8, KJ15, KJ19)의 지하수위 자료와 부산지역의 강우량 자료를 이용하였다. 지하수위 및 강수량은 각각 1일 평균, 1일 누적 값을 이용하였다. 자기상관분석의 경우, KJ2와 KJ19의 경우 지연시간이 2일 이내, KJ8의 경우는 3일 이내에 0으로 수렴하며, KJ15의 경우는 지연시간이 8일째에 0으로 수렴한다. 강수량과 지하수위의 교차상관분석결과, KJ2, KJ15, KJ19호 공은 지연시간이 0일 때 교차상관함수가 각각 0.6572, 0.6303, 0.7857이교 KJ8호 공은 지연시간이 1일 때 0.7141이다. 또한 대부분 짧은 지연시간에 교차상관함수가 0으로 수렴한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.8C
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• pp.681-688
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• 2007

Applying an appropriate received signal processing algorithm based on the channel characteristics is important to improve the receiver performance. Wireless channels in general exhibit various time-delay characteristics depending on their power delay profile. When the estimated channel power summation is used to determine the amount of time delay, a channel adaptive receiver structure can be implemented. In this paper, we derive a closed-form expression for the error probability of the channel classification when the estimated channel power summation is used to classify channel groups having different time delay characteristics, and present the performance gain utilizing multiple estimation results.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.40 no.5
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• pp.241-249
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• 2003

Carry lookahead(CLA) circuitry of decimal adders is proposed aiming at delay reduction. The truncation error in calculation of monetary interests may accumulate yielding a substantial amount of errors. Binary Coded Decimal(BCD) additions. for example, eliminate the truncation error in a fractional representation of decimal numbers. The proposed BCD carry lookahead scheme is aiming at the speed improvements without any truncation errors in the addition of decimal fractions. The delay estimation of the BCD CLA is demonstrated with improved performance in addition. Further reduction in delay can be achieved introducing non-weighted number system such as the excess-3 code.

• Journal of the Korean Geographical Society
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• v.32 no.2
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• pp.129-140
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• 1997

The purpose of this paper is to analyze thermal sensation which is measured bv human physioclimatic reactions in Korea. Human physiological reactions to temperature and relative humidity are analyzed to produce a nomogram from which average human reactions to the climatic factors can be deduced. Thermal - indices for each regular stations in both South (1961-1990) and North Korea(1973-1994) are calculated based on monthly meteorological data. A generalized annual physioclimatic maps for each Annual Cumulative Thermal Index for the 52 stations are constructed to show how men tend to feel in various areas. Resuts of this study can be applied for evaluation of thermal environment in our daily activities, and for searching relevant sports training-sites.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.649-652
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• 2019

Serverless 플랫폼은 작업이 요청되었을 때 인스턴스를 생성하였다가 작업이 끝난 후 제거되기 때문에 실제 작업을 처리할 때만 요금이 부과되어 경제적이다. 하지만 작업이 요청될 경우 인스턴스가 생성되고 작업에 필요한 리소스를 가져오는 지연시간 즉, Cold Start 가 발생한다. 특히 워크플로 실행에서 각 작업이 개별적으로 처리되기 때문에 워크플로의 각 단계마다 Cold Start 가 발생하는데, 워크플로는 사전에 정의되기 때문에 이러한 Cold Start 의 누적은 회피 될 수 있다. 본 논문은 Serverless 환경에서 워크플로를 실행할 때 누적되는 Cold Start 를 완화하기 위해 앞의 단계에서 다음 단계를 미리 준비시키는 런타임 인터페이스들에 대하여 제안한다. 이미지 프로세싱 워크플로에 제안한 런타임 인터페이스를 적용시켜 Cold Start 를 제외한 워크플로의 실행시간을 최대 21%까지 줄였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.9A
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• pp.2305-2312
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• 1998

This paper analyzed the delay characteristics of speech packets in virtual cellular network(VCN). The probability distribution of packet delay is obtained using the markov chain model when periodic speech packets are transmitted by slotted-ALOHA protocol. The effects of probility of capture and retransmission policy on the performance were also analyzed. At first, the probability cumulative function of packet delay is calculated from the probability of capture as a function of location of mobile terminal. In order to investigate the effects of backoff delay, we defined a parameter NPr, where N is the period (frame size) of the speech packets and Pr is the retransmission probability for each speech packet. We also obtained the 1% outage delay for various frame size N.