• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.1 s.232
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• pp.59-66
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• 2005

In this paper, a robust stationary Kalman filter is designed by minimizing selected performance indices so that it is less sensitive to uncertainties. The uncertainties include not only stochastic factors such as process noise and measurement noise, but also deterministic factors such as unknown initial estimation error, modeling error and sensing bias. To reduce the effect on the uncertainties, three performance indices that should be minimized are selected based on the quantitative error analysis to both the deterministic and the stochastic uncertainties. The selected indices are the size of the observer gain, the condition number of the observer matrix, and the estimation error variance. The observer gain is obtained by optimally solving the multi-objectives optimization problem that minimizes the indices. The robustness of the proposed filter is demonstrated through the comparison with the standard Kalman filter.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.889-893
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• 2004

This work presents a study on development of a practical and quantitative technique for assessment of the structural health condition by piezoelectric impedance-based technique associated with longitudinal wave propagation method. The bolt fastening condition is adjusted by torque wrench. In order to estimate the damage condition numerically, three damage indices, impedance peak frequency shift ${\Delta}F$ is proposed in this paper. Furthermore, an assessment method is described for estimation of the damage by using these three damage indices.

• Korean Journal of Remote Sensing
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• v.18 no.5
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• pp.263-271
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• 2002

Recently, spatial information technologies using remotely sensed imagery and functionality of GIS (Geographic Information Systems) have been widely utilized to various types of transportation-related applications. In this study, extraction programs of some practical indices, to be effectively used in transportation reference planning problem, were designed and implemented as prototyped extensions in GIS development environment: traffic flow estimation (TFL/TFB), urban rural index (URI), and accessibility index (AI). In TFL/TFB, user can obtain quantitative results on traffic flow estimation at link/block using high-resolution satellite imagery. Whereas, URI extension provides urban-rural characteristics related to road system, being considered one of important factors in transportation planning. Lastly, AI extension helps to obtain accessibility index between nodes of road segments and surrounding district areas touched or intersected with the road network system, and it also provides useful information for transportation planning problems. This approach is regarded as one of RS-T (Remote Sensing in Transportation), and it is expected to expand as new application of remotely sensed imagery.

• 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.

• Communications for Statistical Applications and Methods
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• v.28 no.2
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• pp.99-118
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• 2021

In this paper, we introduce an extended form of the inverse power Lomax model via Marshall-Olkin approach. We call it the Marshall-Olkin inverse power Lomax (MOIPL) distribution. The four- parameter MOIPL distribution is very flexible which contains some former and new models. Vital properties of the MOIPL distribution are affirmed. Maximum likelihood estimators and approximate confidence intervals are considered under Type I censored samples. Maximum likelihood estimates are evaluated according to simulation study. Bayesian estimators as well as Bayesian credible intervals under symmetric loss function are obtained via Markov chain Monte Carlo (MCMC) approach. Finally, the flexibility of the new model is analyzed by means of two real data sets. It is found that the MOIPL model provides closer fits than some other models based on the selected criteria.

• Nuclear Engineering and Technology
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• v.53 no.1
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• pp.131-141
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• 2021

Simulation is a widely used functional verification method for FBD programs of PLC-based digital I&C system in nuclear power plants. It is difficult, however, to estimate the thoroughness (i.e., effectiveness or quality) of a simulation in the absence of any clear measure for the estimation. This paper proposes two sets of structural coverage adequacy criteria for the FBD simulation, toggle coverage and modified condition/decision coverage, which can estimate the thoroughness of simulation scenarios for FBD programs, as recommended by international standards for functional safety. We developed two supporting tools to generate numerous simulation scenarios and to measure automatically the coverages of the scenarios. The results of our experiment on five FBD programs demonstrated that the measures and tools can help software engineers estimate the thoroughness and improve the simulation scenarios quantitatively.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.159-160
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• 2003

오염물질의 발생원 추정에 관한 연구는 대기오염의 원인이 되는 근본적인 문제를 정량적으로 확인할 수 있으므로 대기질을 종합적으로 관리하고 평가하는데 크게 기여하고 있다. 따라서, 오염원에 대한 기여율을 추정하는 수용모델 (receptor model)이 응용 및 개발되고 있으나 우리나라의 경우 대부분 서울지역과 일부 수도권 이남지역인 수원지역을 중심으로 연구가 집중되고 있을 뿐이며, 수도권 북부지역의 경우 대기오염에 관한 기초조사는 물론이고, 관심조차 낮은 실정에 있다. (중략)

• Proceedings of the Korea Multimedia Society Conference
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• 2000.04a
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• pp.133-136
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• 2000

본 논문에서는 폐암의 변이 형태 분석을 위한 정량적 분석 방법을 연구하였다. 보다 객관적인 분석의 필수적 요인인 정확한 분할을 이해 질감 특징과 통계학적 분류방법을 이용하였으며, 변이 형태 분석을 위해서 분할된 ROI 로부터 여러 가지 형태학적 특성값과 질감 특성값을 추출하여 변이 형태에 따라 비교분석하였다. 이러한 폐암의 변이 형태 분석을 위한 방법은 다른 기관으로의 원격전이가 쉬운 종양의 특성평가에 대한 객관적 병리진단의 보조도구로 사용될 수 있을 것이다.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.05a
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• pp.166-166
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• 2003

In terms of the risk assessment, qualitative and quantitative informations are needed to estimate the exposures of environmental pollutants, which may be potentiality of risks, and those are the information about the changes caused by the chemical transportation among environmental media and transformation in environmental media by duration. The various fate mechanism of chemical is possible for estimation of chemical concentration in environmental media. Since there are limitations in measuring the change of chemical concentration within all medium according to the time period, estimating method through modeling are developed.

• Journal of Biomedical Engineering Research
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• v.7 no.1
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• pp.41-44
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• 1986

The objective of tissue characterization is to provide quantitative information about the physical state of tissue interrogated by an ultrasound beam. In the computer simulation, it was found that the echoes were composed of the interferences of the ultrasonic waves reflected from both sides of the thin object, and could be separated by the spectral correlation method. Also, the phantom study demonstrates that thickness of the thin acryl layer beyond the resolution of common ultrasonic imaging systems can be measured- using this method.