• Title/Summary/Keyword: Level Crossing Rate

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A Study on Safety Investment Moment for Safety Target (철도 안전목표 설성을 위한 안전투자 시점에 대한 연구)

  • Kwak, Sang Log
    • Journal of the Korean Society of Safety
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    • v.32 no.5
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    • pp.122-128
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    • 2017
  • Korean government announced long-term railway safety investment plan for the safety improvement by 2020. But no research have been done about differential analysis on railroad safety investment and safety improvement. In this study, recent 10 year data on safety investments and accident data are analysed for the differential analysis. Three main safety investments are analysed on regard to accident rate and accident fatalities. Three safety measures include level crossing accident, platform fatalities, and track trespass fatalities. About 90% of railway accident fatalities are caused by these three kind of accidents. Differential analysis shows about 4 to 6 years delay after railroad safety investment and safety improvement. This result can be utilized for the decision making on safety measures and safety target. Which required long term approach.

Implementation of Quad Variable Rates ADPCM Speech CODEC on C6000 DSP considering the Environmental Noise (배경잡음을 고려한 4배 가변 압축률을 갖는 ADPCM의 C6000 DSP 실시간 구현)

  • Kim Dae-Sung;Han Kyong-ho
    • Proceedings of the KIPE Conference
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    • 2002.07a
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    • pp.727-729
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    • 2002
  • In this paper, we proposed quad variable rates ADPCM coding method and its implementation on C6000 DSP, which is modified from the standard ADPCM of ITU G.726 for speech quality improvement considering the environmental noise Four coding rates, 16Kbps, 24Kbps, 32Kbps and 40Kbps are used for speech window samples and the rate decision threshold is decided by the environmental noise level. The object of the proposed method is to reduce the coding rate while retaining the speech quality and the speech quality is considerably close to 40Kbps single rate coder with the coding rate close to 16Kbps single rate coder under the environmental noise. The environmental noise level affects the coding rate and the noise level is calculated per every speech window samples. At high noise level, more samples are coded at higher rates to enhance the quality, but at low noise level, only the big speech signals are coded at higher rates and more speech samples are coded at lower coding rates to reduce the coding rates. The influence of the noise on tile speech signal is considerably high for small signals and the small signal has the higher ZCR (zero crossing rate). The method is simulated in PC and to be implemented on C6000 floating point DSP board in real time operations.

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The Analysis of Channel Characteristics on Downtown of Daejeon for K Band Satellite Communication (대전 도심지의 K 대역 위성통신 채널특성 분석)

  • Kwon, Kun-Sup;Heo, Jong-Wan;Hwang, Ki-Min;Lim, Chul-Min;Ryu, Heung-Gyoon
    • Journal of the Korea Institute of Military Science and Technology
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    • v.17 no.5
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    • pp.620-628
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    • 2014
  • This paper describes the analysis results of channel characteristics in the operating area of satellite OTM (On-The-Move) terminal. The communication channel between the Koreasat-5 and OTM terminal on a test car was measured and recorded in downtown of Daejeon, using the received beacon signal of around 20 GHz. And the measurement data were statistically analyzed and then compared with highway and national road environments. The statistical evaluation of satellite channel was conducted by using probability density function and Markov model and then presented average connection duration(ACD), average fade duration(AFD), and level crossing rate(LCR) of downtown environment.

Short-term Fading Characteristics for Mobile Radio Signal in Built-up Areas (대도시 이동전파신호에 대한 단구간 페이딩 특성)

  • 송기홍;김종호;이동두;양기곤
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.5
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    • pp.815-821
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    • 1994
  • Short-term fading in a mobile radio channel is mainly caused by multipath reflected wave by local scatterers or natural obstacles surrounding a mobile unit. In this paper, we analyze probability density function(PDF), level crossing rate(LCR) and widths and depths of fades for the measured field strength data in Seoul and Daejeon areas. As a result, the satatistical distribution of signal variations within any small area with the constant mean value becomes the Rayleigh distribution The variation of fade depths is small regardless of the environment such as urban, suburban. etc. However, the variation of fade widths is large with the change of circumstantial structures and environment. the maximum level crossing rate is obtained near the mean value.

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SNR-independent Methods for Estimating Maximum Doppler Frequency (최대 도플러 주파수 추정 시 대역 조절을 통한 부가 잡음의 영향 완화 기법)

  • Yu Hyun-kyu;Park Goo-hyun;Oh Seong-Mok;Kang Chang-eon;Hong Dae-sik
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.6C
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    • pp.475-480
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    • 2005
  • Information of the maximum Doppler frequency enable to optimize many channel-adaptive techniques and radio resource management methods for mobile radio communication systems. In this paper, we propose two maximum Doppler frequency estimators which are based on the level crossing rate(LCR) and the covariance function (COV). To eliminate the effect of additive noise, we analyze the conditions for the estimators independent of the signal-to-noise ratio(SNR) and implement the conditions with a simple downsampling process. The proposed methods achieve good SNR-independent performance.

An Increment of Crossing Efficiency with Consideration of Pollen Viability Analysis in Rose (장미 교배 효율 증대를 위한 화분 임성 검정)

  • Hwang, Yoon Jung;Song, Chang Min;Kwon, Min Kyung;Kim, Sung Tae;Kim, Won Hee;Han, Youn Yol;Han, Tae Ho;Lim, Ki Byung
    • FLOWER RESEARCH JOURNAL
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    • v.18 no.3
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    • pp.193-200
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    • 2010
  • Current rose cultivars are all composed of heterozygous genome due to long history of out crossing including interspecific hybridization. It has been adapted by artificial selection and crossing by breeders that mainly based on the crossing with fertile pollen derived from inter- or intra-specific hybridization. Pollen viability and germination ability tests provide valuable information for the designing of parentage for more successful breeding efficacy. In this study, we tested the pollen viability and germination ability in seven rose cultivars to find any relationship among several factors including pollen size, ploidy levels, and crossing compatibility. The pollen viability showed wide ranges from 39% 'Pinocchio' as minimum to 82% 'Scarlet Mimi' as maximum, whereas pollen germination rate were from 1% 'Mini Rosa' to 41% 'Scarlet Mimi' as a highest. Pollen size ranged from 41.3 to $45.4{\mu}m$ in large sized pollen and 30.7 to $37.4{\mu}m$ in small sized pollen. The mean diameter of large sized pollen is approximately 10-40% bigger than that of small sized pollen. There are positive relationships among ploidy level, total chromosome length, and pollen size. Crossing list showed that seed setting ratio and seed germination were related to pollen viability, pollen germination, and ploidy level.

AN M/G/1 VACATION QUEUE UNDER THE $P_{\lambda}^M-SERVICE$ POLICY

  • Lee, Ji-Yeon
    • Journal of the Korean Statistical Society
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    • v.36 no.2
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    • pp.285-297
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    • 2007
  • We consider the $P_{\lambda}^M-service$ policy for an M/G/1 queueing system in which the workload is monitored randomly at discrete points in time. If the level of the workload exceeds a threshold ${\lambda}$ when it is monitored, then the service rate is increased from 1 to M instantaneously and is kept as M until the workload reaches zero. By using level-crossing arguments, we obtain explicit expressions for the stationary distribution of the workload in the system.

An M/G/1 Queue under the $P_\lambda\;^M$ with a Setup Time

  • Lee Jiyeon;Kim Jongwoo
    • Proceedings of the Korean Statistical Society Conference
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    • 2004.11a
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    • pp.301-306
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    • 2004
  • We consider the $P_\lambda\;^M$ service policy for an M/G/1 queue in which the service rate is increased from 1 to M at the exponential setup time after the level of workload exceeds $\lambda$. The stationary distribution of the workload is explicitly obtained through the level crossing argument.

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Study on a Scheme of Investment Considering Customer Interruption Cost in Power Distribution System (정전비용을 고려한 배전계통 설비의 투자 계획 수립 방안연구)

  • Chu, Cheol-Min;Kim, Jae-Chul;Lee, Tae-Hee;Moon, Jong-Fil
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2006.05a
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    • pp.365-369
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    • 2006
  • It is concentrated on a methodology to establish a scheme of investment on power distribution systems of components. This paper provides a methodology to estimate the scheme as using a customer interruption cost regarding reliability indices in power distribution systems. The proposed method basically uses the failure rate depending on time for explaining the deterioration of a component. Therefore, the theory of the sensitivity is used for deciding the precedence of the investment to consider an effect of each component's failure rate on the system reliability. After Estimating the sensitivity on component investment cost making incremental reliability level is produced by component's investment cost accumulated according to the precedence of the sensitivity. After that, the failure rate corresponding with reliability level on the curve of investment cost is used as producing the curve of customer interruption cost. Two curves have the crossing point that is proposed to acceptable reliability level for customer and utility. In this paper, the acceptable reliability level for customer with the utility is assessed to analyze customer interruption cost and sensitivity of reliability indices. In conclusion the result of investment based on this method is shown to the reliability level with two cost.

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A study on the recognition system of Korean phenemes using filter-Bank analysis (필터뱅크 분석법을 사용한 한국어 음소의 인식에 관한 연구)

  • 남문현;주상규
    • 제어로봇시스템학회:학술대회논문집
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    • 1987.10b
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    • pp.473-478
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    • 1987
  • The purpose of this study is to design a phoneme-class recognition system for Korean language using filter-bank analysis and zero crossing rate method. First, the speech signals are separated in 16 bandpass filters to obtain short-time spectrum of speech signals, and digitized by 16-ch A/D converter. And then, with the set of features which extracted from patterns of ratios of each channel energy level to overall energy level, the decision rules are made for recognize unknown speech signal. In this experiment, the recognition rate was about 93.1 percent for 7 vowels under multitalker environment and 74.4 percent for 10 initial sounds at single speaker.

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