• Journal of the Korean Society for Precision Engineering
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• v.31 no.11
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• pp.999-1006
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• 2014

In this investigation, we explain the sub-sampling technique of white light scanning interferometry (WLSI) to improve the measurement speed. In addition to the previous work using Fourier domain analysis, several methods to extract the height from the correlogram of WLSI are described with the sub-sampling technique. Especially, Fourier-inverse Fourier transformation method adopting sub-sampling technique is proposed and the phase compensation technique is verified with simulation and experiments. The main advantage of sub-sampling is to speed up the measurements of WLSI but the precision such as repeatability is slightly poor. In case of measuring the sample which has high height step or difference, the proposed technique can be widely used to reduce the measurement time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7C
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• pp.687-695
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• 2005

A bandpass sampling technique, which is a method directly downconverting a bandpass signal to a baseband or a low IF signal without analog mixers, can be an alterative choice for the SDR system to minimize the RF front-end. In this paper, a complex bandpass sampling technique for two bandpass-filtered signals is proposed. We derived generalized formulae for the available sampling range, the signal's IF and the minimum sampling frequency taking into consideration the guard-bands for the multiple RE signals. Thru the simulation experiments, the advantages of the . complex bandpass sampling over the pre-reported real bandpass sampling are investigated for applications in the SDR design.

• Journal of the Earthquake Engineering Society of Korea
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• v.19 no.6
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• pp.293-302
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• 2015

ASCE 4 requires that a hard stop be built around the seismic isolation system in nuclear power plants. In order to maintain the function of the isolation system, this hard stop is required to have clearance-to-stop, which should be no less than the 90th-percentile displacements for 150% Design Basis Earthquake (DBE) shaking. Huang et al. calculated clearance-to-stop by using a Latin Hypercube Sampling technique, without considering the rocking behavior of the isolated structure. This paper investigates the effects on estimation of clearance-to-stop due to 1) rocking behavior of the isolated structure and 2) sampling technique for considering the uncertainties of isolation system. This paper explains the simplified analysis model to consider the rocking behavior of the isolated structure, and the input earthquakes recorded at Diablo Canyon in the western United States. In order to more accurately approximate the distribution tail of the horizontal displacement in the isolated structure, a modified Latin Hypercube Sampling technique is proposed, and then this technique was applied to consider the uncertainty of the isolation system. Through the use of this technique, it was found that rocking behavior has no significant effect on horizontal displacement (and thus clearance-to-stop) of the isolated structure, and the modified Latin Hypercube Sampling technique more accurately approximates the distribution tail of the horizontal displacement than the existing Latin Hypercube Sampling technique.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.5
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• pp.1097-1106
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• 1997

Most works on importance sampling (IS) as an efficient evaluation technique havd been done in an additibe white gaussian noise channel (Awgn). In this paper we propose a CQ(conventional importance sampling and quasi-translantion) IS technique for the mobile radio channel modeled as Rician fading, and analyze the IS estimator's variance to determine optimum IS parameters and the minimum number of run times. Reference showed that CIS technique has a poor performance for systems with meories, but it is shown that the CIS technique can be improved by combining with quasi-translation technique even for systems with memories. Here the CQ IS technique modifies the variance of additive noise and also performs quasi-translation for the fading distribution. We determine the optimum IS parameters of the proposed CQ IS estimator and whow that the simulation gains are about 10$^{3}$~10$^{6}$ for the mobile communication systems with memories in case of the expected BERs 10$^{-5}$ ~10$^{-8}$ .

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1991.04a
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• pp.34-42
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• 1991

This study is directed for the development of an efficient system-level Importance Sampling Technique for system reliability analysis of bridge structures Many methods have been proposed for structural reliability assessment purposes, such as the First-order Second-Moment Method, the Advanced Second-Moment Method, Computer Simulation, etc. The Importance Sampling Technique can be employed to obtain accurate estimates of the required probability with reasonable computation effort. Based on the observation and the results of application, it nay be concluded that Importance Sampling Method is a very effective tool for the system reliability analysis.

• The KIPS Transactions:PartD
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• v.17D no.3
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• pp.185-192
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• 2010

In sensor network environments, each sensor measures the physical environments according to the sampling period, and transmits a sensor reading to the base station. Thus, the sample period influences against importance resources such as a network bandwidth, and a battery power. In this paper, we propose new adaptive sampling technique that adjusts the sampling period of a sensor with respect to the features of sensor readings. The proposed technique predicts a future readings based on KF (Kalman Filter). By using the differences of actual readings and estimated reading, we identify the importance of sensor readings, and then, we adjust the sampling period according to the importance. In our experiments, we demonstrate the effectiveness of our technique.

• Computational Structural Engineering
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• v.4 no.2
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• pp.119-129
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• 1991

This study is directed for the development of an efficient Importance Sampling Technique for system reliability analysis of bridge structures. Many methods have been proposed for structural reliability assessment such as the First-order Second-Moment Method, the Advanced Second-Moment Method, Monte Carlo Simulation, etc. The Importance Sampling Technique can be employed to obtain accurate estimates for the system reliability with reasonable computation effort. Based on the results of example analysis, it may be concluded that Importance Sampling Technique is a very effective tool for the system reliability analysis.

• Communications for Statistical Applications and Methods
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• v.28 no.5
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• pp.493-510
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• 2021

The present article endeavours to develop partial optional randomized - response technique (PORT) to deal with sensitive issues in presence of non-response in successive sampling. Calibration techniques have been embedded with PORT to estimate sensitive population mean at current move in two move successive sampling in presence of non-response. Optimum calibration weights are computed at each move with the aid of constraints based on auxiliary information. Detailed properties of the proposed estimators have been discussed. Possible cases in which non-response may creep at two moves has been explored. The proposed technique has been compared with the modified existing technique. Simulation results indicate that the proposed technique is more efficient than existing, modified one. Suitable recommendations are forwarded.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.385-390
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• 1993

It is the purpose of this paper to present a dialogical tuning method of the sampling period in fuzzy control systems. Last year, the authors gave a dialogical tuning technique of fuzzy control system under the fixed sampling period in this symposium. In the case where sampling period is chosen larger, the response of the control system is unsatisfactory, and in the case where the sampling period is smaller, ineffective control actions are repeated. The appropriate sampling period is chosen through the step response of the closed loop fuzzy control process. As the tuning technique depends on the controlled plant, it is necessary to estimate the rough characteristics of it. The authors propose a method to decide th appropriate sampling period, by inspecting the characteristics of the plant.

• Journal of Biomedical Engineering Research
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• v.25 no.5
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• pp.351-359
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• 2004

Velocity-type repisratory air flow transducer measures dynamic pressure converted from air velocity based on the we1l-known Bernoulli's principle. It requires multiple velocity sampling holes on the flow plane. Measurement error theoretica1ly estimated by computer simulation was demonstrated to significantly reduce by unequally locating the velocity sampling holes. The flow plane was divided into multiple equi-area rings and the sampling holes were located on the circles also equally dividing each ring's area, which decreased measurement error down to 1/5 of the simple equi-radius ring division method. Also, less than 1 ％ relative error was estimated with 4 or more sampling holes. The present technique was less sensitive by <1/2 to the velocity profile change compared to the euqi-radius sampling. Therefore, the present unequal distance velocity sampling technique should be of great use to design the structure of the velocity-type respiratory air flow transducer.