• Title/Summary/Keyword: accelerated sequential

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A class of accelerated sequential procedures with applications to estimation problems for some distributions useful in reliability theory

  • Joshi, Neeraj;Bapat, Sudeep R.;Shukla, Ashish Kumar
    • Communications for Statistical Applications and Methods
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    • v.28 no.5
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    • pp.563-582
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    • 2021
  • This paper deals with developing a general class of accelerated sequential procedures and obtaining the associated second-order approximations for the expected sample size and 'regret' (difference between the risks of the proposed accelerated sequential procedure and the optimum fixed sample size procedure) function. We establish that the estimation problems based on various lifetime distributions can be tackled with the help of the proposed class of accelerated sequential procedures. Extensive simulation analysis is presented in support of the accuracy of our proposed methodology using the Pareto distribution and a real data set on carbon fibers is also analyzed to demonstrate the practical utility. We also provide the brief details of some other inferential problems which can be seen as the applications of the proposed class of accelerated sequential procedures.

A note on the sample size determination of sequential and multistage procedures

  • Choi, Kiheon
    • Journal of the Korean Data and Information Science Society
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    • v.23 no.6
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    • pp.1279-1287
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    • 2012
  • We particularly emphasized how to determine the number of replications with sequential and multistage procedures. So, the t-test is used to achieve some predetermined level of accuracy efficiently with loss function in the case of normal, chi-squared, an exponential distributions. We provided that the relevance of procedures are sequential procedure, two-stage procedure, modified two-stage procedure, three-stage procedure and accelerated sequential procedure. Monte Carlo simulation is carried out to obtain the stopping sample size that minimizes the risk.

An accelerated sequential sampling for estimating the reliability of N-parallel systems

  • Rekab, Kamel;Cheng, Yuan
    • International Journal of Reliability and Applications
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    • v.14 no.2
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    • pp.71-78
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    • 2013
  • The problem of designing an experiment to estimate the reliability of a system that has N subsystems connected in series where each subsystem n has n $T_n$ components connected in parallel is investigated both theoretically and by simulation. An accelerated sampling sheme is introduced. It is shown that the accelerated sampling scheme is asymptotically optimal as the total number of units goes to infinity. Numerical comparisons for a system that has two subsystems connected in series where each subsystem has two components connected in parallel are also given. They indicate that the accelerated sampling scheme performs better than the batch sequential sampling scheme and is nearly optimal.

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Accelerated Sequential Procedure to Estimate the Mean of Unknown Distribution

  • Son, M.S.;Hamdy, H.I.
    • Communications for Statistical Applications and Methods
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    • v.4 no.2
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    • pp.367-376
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    • 1997
  • Consider the accelerated sequential procedure of Hall(1983). Second order asymptotic expression of well behaved functions of the stopping variable. The results is demonstrated by working out several point and interval estimation problems.

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QR Decomposition Based Sequential Belief Propagation Detection Scheme for MIMO Systems (MIMO 시스템을 위한 QR 분해 기반 순차적 신뢰 전파 검출 기법)

  • Park, Sangjoon;Choi, Sooyong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.9
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    • pp.1725-1727
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    • 2015
  • In this letter, a QR decomposition based sequential BP detection scheme is proposed for MIMO systems. The proposed scheme performs the sequential updates from the observation node having the smallest degree among all the observation nodes. Our simulation results verify that the proposed scheme achieves an improved error performance with a significantly accelerated detection convergence speed compared to the conventional schemes.

Implementation and Application of Integrated Model for ALT(Accelerated Life Test) (ALT 통합모형의 적용 및 응용)

  • Choi, Sung-Woon
    • Proceedings of the Safety Management and Science Conference
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    • 2008.11a
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    • pp.153-160
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    • 2008
  • This paper presents the log likelihood function for integrated models for ALT such as exponential-general Eyring, Weibull-temperature and specific heat, lognormal-temperature and specific heat. Additionally this paper estimates the system reliability and mean time to failure(MTTF) for series, parallel, k of n, and standby system using ALT linkage parameter. Lastly this study designs three variable reliability acceptance sampling(RAS) plans such as type I, II censored test, sequential test by the use of integrated models for ALT.

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Molecular Dynamics Free Energy Simulation Study to Rationalize the Relative Activities of PPAR δ Agonists

  • Lee, Woo-Jin;Park, Hwang-Seo;Lee, Sangyoub
    • Bulletin of the Korean Chemical Society
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    • v.29 no.2
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    • pp.363-371
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    • 2008
  • As a computational method for the discovery of the effective agonists for PPARd, we address the usefulness of molecular dynamics free energy (MDFE) simulation with explicit solvent in terms of the accuracy and the computing cost. For this purpose, we establish an efficient computational protocol of thermodynamic integration (TI) that is superior to free energy perturbation (FEP) method in parallel computing environment. Using this protocol, the relative binding affinities of GW501516 and its derivatives for PPARd are calculated. The accuracy of our protocol was evaluated in two steps. First, we devise a thermodynamic cycle to calculate the absolute and relative hydration free energies of test molecules. This allows a self-consistent check for the accuracy of the calculation protocol. Second, the calculated relative binding affinities of the selected ligands are compared with experimental IC50 values. The average deviation of the calculated binding free energies from the experimental results amounts at the most to 1 kcal/mol. The computational efficiency of current protocol is also assessed by comparing its execution times with those of the sequential version of the TI protocol. The results show that the calculation can be accelerated by 4 times when compared to the sequential run. Based on the calculations with the parallel computational protocol, a new potential agonist of GW501516 derivative is proposed.

Low-Power Frequency Offset Synchronization Block Design and Implementation using Pipeline CORDIC (Pipeline CORDIC을 이용한 저전력 주파수 옵셋 동기화기 설계 및 구현)

  • Ha, Jun-Hyung;Jung, Yo-Sung;Cho, Yong-Hoon;Jang, Young-Beom
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.47 no.10
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    • pp.49-56
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    • 2010
  • In this paper, a low-power frequency offset synchronization structure using CORDIC algorithm is proposed. Main blocks of frequency offset synchronization are estimation and compensation block. In the proposed frequency offset estimation block, implementation area is reduced by using sequential CORDIC, and throughput is accelerated by using 2 step CORDIC. In the proposed frequency offset compensation block, pipeline CORDIC is utilized for area reduction and high speed processing. Through MatLab simulation, function for proposed structure is verified. Proposed frequency offset synchronization structure is implemented by Verilog-HDL coding and implementation area is estimated by Synopsys logic synthesis tool.

Enhancement of Seed Germination by Aging, Cold-stratification, and Light Quality during Desiccation in Burcucumber (Sicyos Angulatus L.)

  • Kang, Jin-Ho;Jeon, Byong-Sam;Lee, Sang-Woo;Choe, Zhin-Ryong;Shim, Sang-In
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.48 no.1
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    • pp.13-16
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    • 2003
  • Seeds of burcucumber were treated with accelerated aging, cold-stratification, and light quality illuminated during desiccation to enhance their germination and seedling emergence. The germination was increased by aging and cold-stratification although the latter treatment showed greater effectiveness than the former one. In the combined treatment of aging 6 days at $45^{\circ}C$ and cold-stratification, the germination was promoted under longer period of cold-stratification to reach nearly 100% in 3 week cold-stratification on the ninth day from sowing. In the sequentially combined treatment of aging, cold-stratification, and light quality during 24 hour desiccation at $35^{\circ}C$, no-stratified seeds showed the highest rate in red light treatment but the lowest in far-red light. This implies that the phytochrome action run during the desiccation of imbibed seeds. The red light exposure during drying for the cold-stratified seeds after aging accelerated the germination even more than the dark treatment and germinated 100% on the next day of sowing. It is concluded that the sequential treatment of aging, cold-stratification, and red light illumination during desiccation can highly promote percentage and speed of burcucumber seed germination.

Optimization and Bioassay Guided Comparative Techniques for Efficient Extraction of Lutein Esters from Tagetes erecta (Var. Pusa Narangi Genda) Flowers

  • Kawar Lal Dabodhia;Brijesh Tripathi;Narendra Pal Lamba;Manmohan Singh Chauhan;Rohit Bhatia;Vivek Mishra
    • Mass Spectrometry Letters
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    • v.15 no.1
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    • pp.40-48
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    • 2024
  • Capacity of the analytical/quantitative evaluation techniques to satisfy both qualitative and quantitative considerations for effective extraction of marigold oleoresins/xanthophylls and their potential as anti-mycotic and antioxidant activity was assessed. Accelerated solvent extraction (ASE), Soxhlet extraction (SE), Supercritical fluid extraction (SCFE), Cold extraction (CE), and ultrasonically assisted extraction (USE) techniques were evaluated for extraction of oleoresin/xanthophyll content from Tagetes erecta (Var. Pusa Narangi Genda) with respect to solvent consumption, extraction time, reproducibility, and yield. Followed by the antifungal and antioxidant activity evaluation. The overall yield of Tagetes oleoresin was higher in ASE (64.5 g/kg) followed by SE (57.3 g/kg), USE (50.7 g/kg), SCFE (45.3 g/kg) and CE (31.6 g/kg). The lutein esters represented more than 80% of the constituents. Further, xanthophyll/ lutein content in oleoresin was found to be quite higher in HPLC (r2 = 0.996) analysis than in the AOAC recommended UV spectrophotometer analysis. The oleoresin exhibited moderate antioxidant activity (DPPH assay) and antifungal activity against three phytopathogenic fungi. Based on the various parameters, the reproducibility of ASE was better (0.3-8.0%) than that of SE (0.5-12.9%), SCFE (0.2-9.4%), USE (0.3-12.4%) and CE (0.8-15.3%). ASE with (RSD 1.6%) is preferred being faster, reproducible, uses less solvent, robust and automation allows sequential extraction of the sample in less time.