• Title/Summary/Keyword: Sampling technique

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Global sensitivity analysis improvement of rotor-bearing system based on the Genetic Based Latine Hypercube Sampling (GBLHS) method

  • Fatehi, Mohammad Reza;Ghanbarzadeh, Afshin;Moradi, Shapour;Hajnayeb, Ali
    • Structural Engineering and Mechanics
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    • v.68 no.5
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    • pp.549-561
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    • 2018
  • Sobol method is applied as a powerful variance decomposition technique in the field of global sensitivity analysis (GSA). The paper is devoted to increase convergence speed of the extracted Sobol indices using a new proposed sampling technique called genetic based Latine hypercube sampling (GBLHS). This technique is indeed an improved version of restricted Latine hypercube sampling (LHS) and the optimization algorithm is inspired from genetic algorithm in a new approach. The new approach is based on the optimization of minimax value of LHS arrays using manipulation of array indices as chromosomes in genetic algorithm. The improved Sobol method is implemented to perform factor prioritization and fixing of an uncertain comprehensive high speed rotor-bearing system. The finite element method is employed for rotor-bearing modeling by considering Eshleman-Eubanks assumption and interaction of axial force on the rotor whirling behavior. The performance of the GBLHS technique are compared with the Monte Carlo Simulation (MCS), LHS and Optimized LHS (Minimax. criteria). Comparison of the GBLHS with other techniques demonstrates its capability for increasing convergence speed of the sensitivity indices and improving computational time of the GSA.

A Study on the Determination of Some Heavy Metals using Micro Sampling Technique in Flame Atomic Absorption Spectrophotometry (불꽃원자 흡수 분광법의 Micro Sampling Technique 에 의한 미량 중금속의 분석에 관한 연구)

  • Won Lee
    • Journal of the Korean Chemical Society
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    • v.29 no.3
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    • pp.220-225
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    • 1985
  • An attempt was made to determine some trace metals in highly concentrated samples using micro sampling technique in flame atomic absorption spectrophotometry. Major instrumental parameters and optimun analytical conditions investigated were the measuring time of instrument (the speed of electronics), sample volume, burner height, aspiration rate, and fuel to oxidant ratio. Advantages of the present technique are not only rapid, simple, and sensitive with good precision but also capability of analyzing small volume of sample and ability to handle highly concentrated samples without serious burner clog-up problem compared to conventional flame atomic absorption.

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Multistage Point and Confidence Interval Estimation of the Shape Parameter of Pareto Distribution

  • Hamdy, H.I.;Son, M.S.;Gharraph, M.K.;Rashad, A.M.
    • Communications for Statistical Applications and Methods
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    • v.10 no.3
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    • pp.1069-1086
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    • 2003
  • This article presents the asymptotic theory of triple sampling procedure as pertain to estimating the shape parameter of Pareto distribution. Both point and confidence interval estimation are considered within the same inference unified framework. We show that this group sampling technique possesses the efficiency of Anscome (1953), Chow and Robbins (1965) purely sequential procedure as well as reduce the number of sampling operations by utilizing Stein (1945) two stages procedure. The analysis reveals that the technique performs excellent as far as the accuracy is concerned. The present problem differs from those considered by many authors, in multistage sampling, in that the final stage sample size and the parameter's estimate become highly correlated and therefore we adopted different approach.

A Low Bit Rate Speech Coder Based on the Inflection Point Detection

  • Iem, Byeong-Gwan
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.15 no.4
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    • pp.300-304
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    • 2015
  • A low bit rate speech coder based on the non-uniform sampling technique is proposed. The non-uniform sampling technique is based on the detection of inflection points (IP). A speech block is processed by the IP detector, and the detected IP pattern is compared with entries of the IP database. The address of the closest member of the database is transmitted with the energy of the speech block. In the receiver, the decoder reconstructs the speech block using the received address and the energy information of the block. As results, the coder shows fixed data rate contrary to the existing speech coders based on the non-uniform sampling. Through computer simulation, the usefulness of the proposed technique is shown. The SNR performance of the proposed method is approximately 5.27 dB with the data rate of 1.5 kbps.

Parameter Estimation of Linear-FM with Modified sMLE for Radar Signal Active Cancelation Application

  • Choi, Seungkyu;Lee, Chungyong
    • IEIE Transactions on Smart Processing and Computing
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    • v.3 no.6
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    • pp.372-381
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    • 2014
  • This study examined a radar signal active cancelation technique, which is a theoretical way of achieving stealth by employing a baseband process that involves sampling the incoming hostile radar signal, analyzing its characteristics, and generating countermeasure signals to cancel out the linear-FM signal of the hostile radar signal reflected from the airborne target. To successfully perform an active cancelation, the effects of errors in the countermeasure signal were first analyzed. To generate the countermeasure signal that requires very fast and accurate processing, the down-sampling technique with the suboptimal maximum likelihood estimation (sMLE) scheme was proposed to improve the speed of the estimation process while preserving the estimation accuracy. The simulation results showed that the proposed down-sampling technique using a 2048 FFT size yields substantial power reduction despite its small FFT size and exhibits similar performance to the sMLE scheme using the 32768 FFT size.

The Productivity Improvement for Steel Framing Work Efficiency by Work Sampling and 5-minute Rating Technique

  • Chang, SooWon;Yi, June-Seong;Son, JeongWook
    • Journal of Construction Engineering and Project Management
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    • v.5 no.1
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    • pp.40-46
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    • 2015
  • This study presents the results of our analysis and recommendations for process and productivity improvements. The project studied consists of a 5-story research building, with a structure of steel frames supporting concrete slabs. The observations focused on the analysis of the overall erection and framing process. The methods used for the analysis consisted in intensive visits on site, where construction processes were observed in term of resources, activities, durations, materials' handling procedures, and technology used. Back to the office, authors used the information captured to model the different trades' activities, using work sampling and 5-minute rating technique. The work sampling provides insight into the activity, hence allowing for process improvements. The productivity of various trades is strongly dependent on the organization of the work process and work site conditions. Improving the productivity of the entire project or company is not possible until everyone is committed to improvement.

Sampling Procedures Enhancement in Government Defense Quality Assurance Procedures: Case Studies in Combat Force Support Material & Ammunition Areas (국방 품질보증 활동 강화를 위한 샘플링 방법 개선: 전투물자 및 탄약 분야 사례 위주)

  • Ahn, Nam-Su;Jeong, Ji-Sun;Jeong, Woon-Kwon;Hwang, Woo-Yull;Park, Sang-Won
    • Journal of Korean Society for Quality Management
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    • v.40 no.3
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    • pp.245-258
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    • 2012
  • Purpose: Recently, many quality issues are aroused in military forces, such as failures in K-series weapons, combat boots defects and 40mm ammunition explosion accident. To address these problems, the one and only government defense quality assurance agency, DTaQ(Defense Agency for Technology & Quality) tried to improve many quality assurance procedures and introduced new systems such as MRA(Manufacturing Readiness Assessment), TRA(Technology Readiness Assessment), and etc. However, as the amount of war supplies increasing every year, the resource(budget and manpower) for quality assurance is limited. Therefore, DTaQ had difficulty to handle the issue efficiently and effectively, and we propose the method to address this problem. Methods: The most popular quality assurance technique is a sampling method, in this research, we first review the many sampling techniques and compare the strength and weakness of each method. After then, we selected the most appropriate sampling techniques and applied the procedures in combat force support material and ammunition areas. Results: We can reduce the number of samples dramatically, thus the required amount of labor time and money can be saved. Also, the new sampling technique enforces the supplier to produce the product which meets the target value(desirable value). Conclusion: We can reduce the number of samples dramatically, thus the required amount of labor time and money can be saved. Also, the new sampling technique enforces the supplier to produce the product which meets the target value(desirable value). Lastly, since the new sampling method requires many numerical calculations, we developed a simple android OS smart-phone application which can be used easily in field.

Compensation of Timing Offset and Frequency Offset in the Multi-Band Receiver with Sub-Sampling Method (Sub-Sampling 방식의 다중 대역 수신기에서 타이밍 오프셋과 주파수 오프셋 보상)

  • Lee, Hui-Kyu;Ryu, Heung-Gyoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.5
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    • pp.501-509
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    • 2011
  • Software defined radio(SDR) has a goal that places the analog-to-digital converter(ADC) as near the antenna as possible. But current technique actually can't do analog-to-digital converting about RF band signals. So one method is studying that samples RF band signals to IF band. One of the ways Sub-Sampling technique can convert signals from RF band to IF band without oscillator. If Sub-Sampling technique is used, over 2 bands can convert signals from RF band to IF band. But due to the filter performance in RF band, it is possible to generate interference between signals that is converted in low frequency band. The effect degrades performance. In this paper, we propose one method that uses time division multiplexing(TDM) method as a solution to avoid interference between signals. By doing TDM and Sub-Sampling at the same time that method can get signals without large changes of structures.

속산 시뮬레이션에 의한 ATM 텔레트래픽 연구

  • 국광호;이창호;오창환;강성렬
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 1996.04a
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    • pp.553-556
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    • 1996
  • The cell loss probability recommended in the B-ISDN is in the range of 10$^{-8}$ ~ 10$^{-12}$ . When a simulation technique is used to analyze the performance of the ATM switching system, an enormous amount of computer time is required. In this study, we derive an importance sampling simulation technique that can be used to evaluate the loss probability obtained by the importance sampling simulation is very close to that obtained by the ordinary simulation and the computer time can be reduced drastically by the importance sampling simulation.

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Prosody Control of the Synthetic Speech using Sampling Rate Conversion (표본화율 변환을 이용한 합성음의 운율제어)

  • 이현구;홍광석
    • Proceedings of the IEEK Conference
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    • 1999.11a
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    • pp.676-679
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    • 1999
  • In this paper, we presents a method to control prosody of the synthetic speech using sampling rate conversion technique. In prosody control, the conventional methods perform overlap and add. So the synthetic speech has a distortion and the voice quality is not satisfied. Using sampling rate conversion technique, we can get high Qualify of the synthetic speech. Also we can control various talking speeds according to speaker's patterns.

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