• Title/Summary/Keyword: Sampler

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Bayesian Estimation of State-Space Model Using the Hybrid Monte Carlo within Gibbs Sampler

  • Park, Ilsu
    • Communications for Statistical Applications and Methods
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    • v.10 no.1
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    • pp.203-210
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    • 2003
  • In a standard Metropolis-type Monte Carlo simulation, the proposal distribution cannot be easily adapted to "local dynamics" of the target distribution. To overcome some of these difficulties, Duane et al. (1987) introduced the method of hybrid Monte Carlo(HMC) which combines the basic idea of molecular dynamics and the Metropolis acceptance-rejection rule to produce Monte Carlo samples from a given target distribution. In this paper, using the HMC within Gibbs sampler, an asymptotical estimate of the smoothing mean and a general solution to state space modeling in Bayesian framework is obtaineds obtained.

Accelerating Scanline Block Gibbs Sampling Method using GPU (GPU 를 활용한 스캔라인 블록 Gibbs 샘플링 기법의 가속)

  • Zeng, Dongmeng;Kim, Wonsik;Yang, Yong;Park, In Kyu
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2014.06a
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    • pp.77-78
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    • 2014
  • A new MCMC method for optimization is presented in this paper, which is called the scanline block Gibbs sampler. Due to its slow convergence speed, traditional Markov chain Monte Carlo (MCMC) is not widely used. In contrast to the conventional MCMC method, it is more convenient to parallelize the scanline block Gibbs sampler. Since The main part of the scanline block Gibbs sampler is to calculate message between each edge, in order to accelerate the calculation of messages passing in scanline sampler, it is parallelized in GPU. It is proved that the implementation on GPU is faster than on CPU based on the experiments on the OpenGM2 benchmark.

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Use of New Passive Sampler to Assess PAHs Contamination (새로운 생물농축 기법에 의한 PAHs의 오염도 확인)

  • 박정규;황인영;문성환;정홍배
    • Environmental Analysis Health and Toxicology
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    • v.16 no.4
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    • pp.171-179
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    • 2001
  • A new passive sampler was developed, improving SPMD (Semipermeable Membrane Devices) that contained triolein in nonporous, low-density polyethylene layflat tubing. Experiments to measure PAHs concentration were carried out at four sites (Dukpo, Sochi, Sohwonggando, Yeonmok) on the southern coast of Korea that were contaminated by oil spills. Passive samplers were deployed at 4 and 8 week intervals at each site. Results showed that bioconcentration levels of PAHs were increased in proportion to exposure duration from all sample sites and accumulation in the passive sampler was much higher than in biota at the Dukpo site. Results of these tests suggest that new passive sampler is a useful tool for measuring bioconcentration organic compounds in aquatic environments.

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An Estimation of Carbamate Pesticide Exposure in a Rural Area - A pilot study using personal sampler and gas chromatography - (일부 농촌지역에서의 Carbamate 농약 폭로도의 추정 - 개인용 포집기와 Gas Chromatography 분석을 이용한 예비조사 -)

  • Kim, Byung-Hee;Kim, Yong-Sik;Choi, Jin-Su
    • Journal of Preventive Medicine and Public Health
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    • v.23 no.2 s.30
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    • pp.201-206
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    • 1990
  • The exposures to carbamate pesticides (BPMC specifically) of agricultural workers were estimated by collecting pesticide in air by personal sampler and by analyzing with gas chromatography. Data revealed that the highest BPMC concentration in the aspirated air was $7.7mg/m^3$. Concentrations were generally higher in the group whose spray conditions were controlled than the group uncontrolled. Actual concentations were relatively lower than the values predicted theoretically. These findings suggest that personal sampler be useful in the estimation of pesticide exposure.

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Measurement of Dry Deposition Flux of Air Pollutants to the Waterbody (수체로의 대기오염물질 건식침적량 측정)

  • 김영성;진현철;김용표
    • Journal of Korean Society for Atmospheric Environment
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    • v.20 no.3
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    • pp.421-426
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    • 2004
  • Dry deposition fluxes of inorganic acidic species to the waterbody were measured by the dry deposition sampler (DDS). DDS was composed of three pans filled with pure water. An average concentration increase during the sampling time, after removing an abnormal value if existed, was considered as the input by deposition. Important operation parameters such as the amount of water used and sampling time were determined through a series of laboratory experiments. The deposition flux measured by DDS was compared with that by the water surface sampler developed by Yi et ai. (1997a,b).

Sampler Model of P-type Current Mode Control Utilizing Low Pass Filter (저역 통과 필터를 사용하는 P-type 전류모드제어의 샘플러 모델)

  • Jung, Young-Seok
    • The Transactions of the Korean Institute of Power Electronics
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    • v.17 no.5
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    • pp.388-392
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    • 2012
  • In this paper, a sampler model for the P-type current mode control employing low pass filter is proposed. Even though the frequency response of the compensator used in a P-type current mode control employing low pass filter is similar to that of P-type compensator, the sampler model has to be obtained from the method used in PI-type current mode control. In order to show the usefulness of the proposed method, prediction results of the proposed model are compared to those from the circuit level simulator, PSIM.

Development of Automatic Water Sampler with Sensor for Practical Measurement (현장측정용 센서부착 자동채수기 개발)

  • Kim, Jin-Hyok;Han, Seong-Kuk;Lee, Jin-Pill;Kim, Jae-Yong
    • Applied Chemistry for Engineering
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    • v.21 no.6
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    • pp.632-637
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    • 2010
  • Considering the water quality regulation of total emission system which is enforced with hydro TMS and so on operating currently, automatic water sampler must be necessary in the viewpoint of national interest for conservation of water resources. This study aimed to develope automatic water sampler for the purpose of decreasing spends on foreign currency which is relied on import from abroad and upgrading the functional efficiency simultaneously. We have made an effort for developing results as follows with some cases. First, flow meter with a sensor equiped into automatic water sampler for field measurement which can perform linkage operation was developed. Second, remote-D/L system was developed which was able to monitor and store some transmitted data from practical measurement sensor. Also, automatic water sampler was developed in this research that operates in a sewage treatment plant, and finally, we confirmed that our system is able to apply to the field well.