• 한국지진공학회논문집
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• 제26권1호
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• pp.1-11
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• 2022

In this study, the seismic performance of a two-story unreinforced masonry (URM) building was assessed following the linear and nonlinear static procedures specified in the seismic evaluation guideline of existing buildings. First, the provisions to assess failure modes and shear strengths of URM walls and wall piers were reviewed. Then, a two-story URM building was assessed by the linear static procedure using m-factors. The results showed that the walls and wall piers with aspect ratios h_e // (i.e., effective height-to-length ratio) > 1.5 were unsafe due to rocking or toe crushing, whereas the walls with h_e // ≤ 1.5 and governed by bed-joint sliding mainly were safe. Axial stresses and shear forces acted upon individual masonry walls, and wall piers differed depending on whether the openings were modeled. The masonry building was reevaluated according to the nonlinear static procedure for a more refined assessment. Based on the linear and nonlinear assessment results, considerations of seismic evaluation for low-rise masonry buildings were given with a focus on the effects of openings.

• 환경영향평가
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• 제17권2호
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• pp.125-132
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• 2008

It is desirable that implementation assessment (IA) should be carried out efficiently in order to make successful progress of Total Maximum Daily Load (TMDL) in watershed management. There are many difficulties in the process of the implementation assessment because of the early stage in the application of TMDL in Korea. This study reviewed the present status of IA and proposed the methodology of its improvement such as flexible application of TMDL ledger, and standardization of assessment index and criteria. The deficient time for assessment period could be corrected by the consideration of the post-procedure after the submission of IA report.

• 대한수학교육학회지:학교수학
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• 제4권2호
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• pp.193-204
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• 2002

Performance assessment has been introduced to school education as an alternative measure of the former educational assessment which put much emphasis on the result rather than the process of learning, memorization than pursuit of knowledge, and passive than active study. As for the subject of mathematics, the change of the assessment came to replace multiple choice tests with descriptive- and statement-type tests. This means animprovement on the testing system, focusing on the process of finding out the answer. The main focus, however, is still on the intellectual domain without paying due attention to the emotional domain of mathematics education. The previous studies on the assessment of emotional domain In mathematics have shown that there are stumbling blocks in the application of the assessment, such as the disputes on the reliability, objectivity, and fairness as well as the complicated procedure of applying the results to school records. The lack of the development and supply of the appropriate assessment tools have also been pointed out. Therefore, this study has been carried out with the intention of establishing an applicable standard of assessment on the emotional domain of high school matematics. As a result, detailed standards of performance assessment, which adopt oral examination, discussion, observation, and report have been developed. The problems which are likely to emerge In the course of the application of the newly developed assessment are under study as a continuing research project.

• Structural Engineering and Mechanics
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• 제52권2호
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• pp.307-322
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• 2014

A two-step procedure to detect and quantify damages in structures from changes in curvature mode shapes is presented here. In the first step the maximum difference in curvature mode shapes of the undamaged and damaged structure are used for visual identification of the damaged internal-substructure. In the next step, the identified substructures are searched using unified particle swarm optimization technique for exact identification of damage location and amount. Efficiency of the developed procedure is demonstrated using beam like structures. This methodology may be extended for identifying damages in general frame structures.

• Journal of Electrical Engineering and Technology
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• 제7권4호
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• pp.493-500
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• 2012

In this paper the performance of meta-heuristics algorithms such as GA (Genetic Algorithm), DE (Differential Evolution), PSO (Particle Swarm Optimization) and SA (Simulated Annealing) for the problem of TTC enhancement using FACTS devices are compared. In addition to that in the assessment procedure of TTC two novel techniques are proposed. First the optimization algorithm which is used for TTC enhancement is simultaneously used for assessment of TTC. Second the power flow is done using Broyden - Shamanski method with Sherman - Morrison formula (BSS). The proposed approach is tested on WSCC 9 bus, IEEE 118 bus test systems and the results are compared with the conventional Repeated Power Flow (RPF) using Newton Raphson (NR) method which indicates that the proposed method provides better TTC enhancement and computational efficacy than the conventional procedure.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 춘계학술발표회논문집(1)
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• pp.611-616
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• 1997

The Level 1 probabilistic safety assessment(PSA) for Wolsong(WS) 2/3/4 nuclear power plant(NPPs) in design stage is performed using the methodologies being equivalent to PWR PSA. Accident sequence evaluation program(ASEP) human reliability analysis(HRA) procedure and technique for human error rate prediction(THERP) are used in HRA of WS 2/3/4 NPPs PSA. The purpose of this paper is to introduce the procedure and methodology of HRA in WS 2/3/4 NPPs PSA. Also, this paper describes the interim results of importance analysis for human actions modeled in WS 2/3/4 PSA and the findings and recommendations of administrative control of secondary control area from the view of human factors.

• Communications for Statistical Applications and Methods
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• 제8권2호
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• pp.453-464
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• 2001

A commercial nuclear power station contains at least tow emergency diesel generators(EDG) to control the risk of severe core damage during station blackout accidents. Therefore, the reliability of the EDG's to start and load-run on demand must be maintained at a sufficiently high level. Probabilistic safety assessments(PSA) are increasingly being used to quantify the public risk of operating potentially hazardous systems such as nuclear power reactors. In this paper, to perform PSA, we will introduce three different types of data and use Bayes procedure to estimate the error rate of nuclear power plant EDG, and using practical examples, illustrate which method is more reasonable in our situation.

• 한국신뢰성학회지:신뢰성응용연구
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• 제9권1호
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• pp.1-12
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• 2009

BLDC motors are stored in the devices such as CD-RW, COMBO, DVD-ROM and CD-ROM. It is indispensable to establish reliability assessment criteria for BLDC motors, especially in the world where IT grows rapidly. In this article, reliability certification procedure is given. The reliability certification procedure consists of two separate tests such as quality certification test and lifetime test. The former quality certification test comprises general performance test and environmental test. Items which pass the test undergo lifetime test which guarantees the extent of mean lifetime with certain confidence.

• Steel and Composite Structures
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• 제24권3호
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• pp.369-382
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• 2017

This study investigates the reliability of the performance levels of moment resisting steel frames subjected to lateral loads such as wind and earthquake. The reliability assessment has been performed with respect to three performance levels: serviceability, damageability, and ultimate limit states. A four-story moment resisting frame is used as a typical example. In the reliability assessment the uncertainties in the loadings and in the capacity of the frame have been considered. The wind and earthquake loads are assumed to have lognormal distribution, and the frame resistance is assumed to have a normal distribution. In order to obtain an appropriate limit state function a linear relation between the loading and the deflection is formed. For the reliability analysis an algorithm has been developed for determination of limit state functions and iterations of the first order reliability method (FORM) procedure. By the method presented herein the multivariable analysis of a complicated reliability problem is reduced to an S-R problem. The procedure for iterations has been tested by a known problem for the purpose of avoiding convergence problems. The reliability indices for many cases have been obtained and also the effects of the coefficient of variation of load and resistance have been investigated.

• 한국잡초학회지
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• 제17권1호
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• pp.73-79
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• 1997

Governments and industry have a growing interest in the harmonization of environmental test methods and risk assessment procedures. OECD are currently producing a set of harmonised test guidelines for studying the environmental fate and ecological effects of pesticides. FAO has published an environmental risk assessment procedure. This procedure, which is similar to those used in US and Europe, is based on calculating the ratio of the toxicity of a pesticide to indicator organisms to their level of exposure to the pesticide. The exposure depends on both the concentration of the pesticide and its bioavailability. Ratios which indicate a pesticide will not produce a harmful effect have been established using ecological field studies. Examples are presented for assessing the risk to aquatic ecosystems, earthworms and honeybees. Long-term field studies(up to 20 years) have also shown that pesticides can be used indefinitely without harming soil fertility. Herbicides can be used to avoid the ecologically damaging effects of using soil cultivations excessively for weed control.