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An Approximation to the Overshoot in M/En/1 Queues (M/En/1 큐에서 Overshoot에 대한 근사)

  • Bae, Jong-Ho;Jeong, Ah-Reum;Kim, Sung-Gon
    • The Korean Journal of Applied Statistics
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    • v.24 no.2
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    • pp.347-357
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    • 2011
  • In this paper, we propose an approximation to the overshoot in M/$E_n$/1 queues. Overshoot means the size of excess over the threshold when the workload process of an M/$E_n$/1 queue exceeds a prespecified threshold. The distribution, $1^{st}$ and $2^{nd}$ moments of overshoot have an important role in solving some kind of optimization problems. For the approximation to the overshoot, we propose a formula that is a convex sum of the service time distribution and an exponential distribution. We also do a numerical study to check how exactly the proposed formula approximates the overshoot.

Dynamic model updating of the laminated composite plate using natural frequencies measured from modal test (고유진동수의 실험값을 사용한 복합재 적층판의 동적 모델링 개선)

  • 홍단비;유정규;박성호;김승조
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1998.04a
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    • pp.340-346
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    • 1998
  • In order to improve the prediction of dynamic behavior in structures, several lower vibration modes from FFT analysis through experiments are used to update the mechanical properties followed by the updated frequencies from numerical analysis. Performance index consists of the sum of error norms between the chosen frequencies and corresponding frequencies from numerical analysis. As an updating process of the natural frequencies, the optimization algorithm based on conjugate gradient method is adopted. The gradient of performance index is calculated using the sensitivity of selected eigenvalues with respect to each design parameter. The mechanical properties of lamina, E$\_$l/, E$\_$2/, .nu.$\_$12/ and G$\_$12/, are design parameters for the updating process. The proposed method is applied to predict the dynamic behavior of composite laminated plates of [0]$\_$8T/ and [.+-.45]$\_$2S/ separately or interchangeably. Also, the mixed case for [0]$\_$8T/ and [.+-.45]$\_$2S/ is exarm'ned to check the possibility for the improved prediction generally. The good agreement is obtained between the measured frequencies and the numerical ones. Based on the results for all the cases studied, the proposed approach has a clear potential in characterizing the mechanical properties of composite lamina.

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Formant Measurements of Complex Waves and Vowels Produced by Students (복합음과 대학생이 발음한 모음 포먼트 측정)

  • Yang, Byung-Gon
    • Speech Sciences
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    • v.15 no.3
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    • pp.39-51
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    • 2008
  • Formant measurements are one of the most important factors to objectively test cross-linguistic differences among vowels produced by speakers of any given languages. However, many speech analysis softwares present erroneous estimates and some researchers use them without any verification procedures. The purposes of this paper are to examine formant measurements of complex waves which were synthesized from the average formant values of five Korean vowels using three default methods in Praat and to verify the measured values of the five vowels produced by 20 students using one of the methods. Variances along the time axis are discussed after determining absolute difference sum from the 1/3 vowel duration point. Results show that there were smaller measurement errors by the burg method. Also, greater errors were observed in the sl or lpc methods mostly caused by the inappropriate formant settings. Formant measurement deviations were greater in those vowels produced by the female students than those of the male students, which were mostly attributed to the settings for the vowels /o, u/. Formant settings can best be corrected by changing the number of formants to the number of visible dark bands on the spectrogram. Those results suggest that researchers should check the validity of the estimates from the speech analysis software. Further studies are recommended on the perception test of the original sound with the synthesized sound by the estimated formant values.

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Design of Dynamic Time Warp Element for Speech Recognition (음성인식을 위한 Dynamic Time Warp 소자의 설계)

  • 최규훈;김종민
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.3
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    • pp.543-552
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    • 1994
  • Dynamic Time Warp(DTW) needs for iterative calculations and the design of PE cell suitable for the operations is very important. Accordingly, this paper aims at real time recognition design enables large dictionary hardware realization using DTW algorithm. The DTW PE cell separated into three large blocks. "MIN" is the one block for counting accumulated minimum distance. "ADD" block calculates these minimum distances, and "ABS" seeks for the absolute values to the total sum of local distances. Circuit design and verification about the three block have been accomplished, and performed layout '||'&'||' DRC(design rule check) using 1.2 m CMOS N-Well rule base.CMOS N-Well rule base.

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Low Power LDPC Deocder Using Adaptive Forced Convergence algorithm (적응형 강제 수렴 기법을 이용한 저전력 LDPC 복호기)

  • Choi, Byung Jun;Bae, JeongHyeon;Sunwoo, Myung Hoon
    • Journal of the Institute of Electronics and Information Engineers
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    • v.53 no.12
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    • pp.36-41
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    • 2016
  • LDPC code has beend applied in recent communication standards, such as Wi-Fi, WiGig, 10GBased-T Ethernet as a forward error correction code. However, LDPC code is required a large amount of computational complexity due to large iterations and block lengths for high performances. To solve this problem, various research has been continously performed for reducing computational complexity. In this paper, we propose AFC algorithm to deactive the variable and check node for reduce the computational complexity.

A Novel LDPC Decoder with Adaptive Modified Min-Sum Algorithm Based on SNR Estimation (SNR 예측 정보 기반 적응형 Modified UMP-BP LDPC 복호기 설계)

  • Park, Joo-Yul;Cho, Keol;Chung, Ki-Seok
    • IEMEK Journal of Embedded Systems and Applications
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    • v.4 no.4
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    • pp.195-200
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    • 2009
  • As 4G mobile communication systems require high transmission rates with reliability, the need for efficient error correcting code is increasing. In this paper, a novel LDPC (Low Density Parity Check) decoder is introduced. The LDPC code is one of the most popular error correcting codes. In order to improve performance of the LDPC decoder, we use SNR (Signal-to-Noise Ratio) estimation results to adjust coefficients of modified UMP-BP (Uniformly Most Probable Belief Propagation) algorithm which is one of widely-used LDPC decoding algorithms. An advantage of Modified UMP-BP is that it is amenable to implement in hardware. We generate the optimal values by simulation for various SNRs and coefficients, and the values are stored in a look-up table. The proposed decoder decides coefficients of the modified UMP-BP based on SNR information. The simulation results show that the BER (Bit Error Rate) performance of the proposed LDPC decoder is better than an LDPC decoder using a conventional modified UMP-BP.

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An Integrated MIN Circuit Design of DTW PE for Speech Recognition (음성인식용 DTW PE의 IC화를 위한 MIN회로의 설계)

  • 정광재;문홍진;최규훈;김종교
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.15 no.8
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    • pp.639-647
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    • 1990
  • Dynamic time warp(DTW) needs for interative calculations and the design of PE cell suitable for the operations is very important. Accordingly, this paper aims at the real time recognition design which enables large dictionary hardware realization using DTW algorithm. The DTW PE cell is seperated into three large blocks. "MIN" is the one block for counting accumulated minimum distance, "ADD" block calculates these minimum distances, and "ABS" seeks for the absolute values to the total sum of local distances. We have accomplisehd circuit design and verification for the MIN blocks, and performed MIN layout and DRC(design rule check) using 3um CMOS N-Well rule base.ing 3um CMOS N-Well rule base.

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A Study on the Tasks 119 Fire Service -The Two City of Fire & Disaster Management Department- (119 구급대원들의 업무에 관한 연구 -2개 광역시 소방구급대를 중심으로-)

  • Kim, Mi Sook;Yeo, Jin Dong
    • The Korean Journal of Health Service Management
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    • v.1 no.1
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    • pp.90-109
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    • 2007
  • This Study aims to examine the relative importants of various tasks of EMT and to examine knowledge level and problems associated with AED. It is based on the survey of paramedics and rescurers. The instrument by Hoe Sum Lim(1999) was used. as the questionaire for this research. The collected data were analyzed by means of $x^2$ test, t-test, and measured by percents. The results for this study were follows: 1) Among the tasks of EMI, "Basic Life Support" were rated as the most important, followed by "O2 supply" and foreign-body removal from mouth. 2) Some of the lower level of importance in task were Intubation, IV, dextrose infusion of Hypoglycemia, NTG S/L for chest pain, hydration for fluid therapy, brochodilator IV for Bronchial Asthma. 3) Some of the lower level of importance in task were apply of MAST, Vital Sign check and administration of traction & spine immobilization & air splint. 4) The most important reason that the used of AED is delayed is "unclear boundary of treatment directed by medical control".

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Seismic Qualification Analysis of a Small Savonius Style Vertical Axis Wind Turbine (소형 사보니우스형 수직축 풍력발전기의 내진검증)

  • Choi, Young-Hyu;Kang, Min-Gyu;Park, Sung-Hoon
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.17 no.1
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    • pp.122-129
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    • 2018
  • This study conducted a seismic qualification analysis of small savonius style vertical axis wind turbine(VAWT) using finite element method(FEM). The modal analysis was performed on the wind turbine structure to check the occurrence of resonance caused by the rotation of gearbox and windmill blades. Next, it conducted a seismic response spectrum analysis due to horizontal and vertical seismic load of required response spectrum of safe shutdown earthquake with 5 % damping(RRS/SSE 5%) of KS C IEC 61400 and conducted a static analysis due to deadweight and wind load. The total maximum stress of the VAWT structure was calculated by adding the maximum stresses due to each load case using the square root of the sum of the squares(SRSS) method. Finally, the structural safety of the VAWT structure was verified by comparing the total maximum stress and the allowable stress.

Development of the intermittency turbulence model for a plane jet flow (자유 평면 제트유동 해석을 위한 간혈도 난류모델의 개발)

  • 조지룡;정명균
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.11 no.3
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    • pp.528-536
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    • 1987
  • In a turbulent free shear flow, the large scale motion is characterized by the intermittent flow which arises from the interaction between the turbulent fluid and the irrotational fluid of the environment through the mean velocity gradient. This large scale motion causes a bulk convection whose effect is similar to the spatial diffusion process. In this paper, the total diffusion process is proposed to be approximated by weighted sum of the bulk convection due to the large scale motion and the usual gradient diffusion due to small scale motion. The diffusion term in conventional .kappa.-.epsilon. model requires on more equation of the intermittency transport equation. A production term of this equation means mass entrainment from the irrotational fluid to the turbulent one. In order to test the validity of the proposed model, a plane jet is predicted by this method. Numerical results of this model is found to yield better agreement with experiment than the standard .kappa.-.epsilon. model and Byggstoyl & Kollmann's model(1986). Present hybrid diffusion model requires further tests for the check of universality of model and for the model constant fix.