• International Journal of Highway Engineering
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• v.18 no.4
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• pp.63-68
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• 2016

PURPOSES : The nonlinear model of fatigue cracking is typically used for determining the maintenance period. However, this requires that the model parameters be known. In this study, the particle filter (PF) method was used to determine various statistical parameters such as the mean and standard deviation values for the nonlinear model of fatigue cracking. METHODS : The PF method was used to determine various statistical parameters for the nonlinear model of fatigue cracking, such as the mean and standard deviation. RESULTS : On comparing the values obtained using the PF method and the least square (LS) method, it was found that PF method was suitable for determining the statistical parameters to be used in the nonlinear model of fatigue cracking. CONCLUSIONS : The values obtained using the PF method were as accurate as those obtained using the LS method. Furthermore, reliability design can be applied because the statistical parameters of mean and standard deviation can be obtained through the PF method.

• Journal of Aerospace System Engineering
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• v.6 no.1
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• pp.19-25
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• 2012

Nowadays, the demand of civil application of an UAV has been being increased all over the world. And many projects are going on to develop a new regulatory system for an UAV to access a national airspace. Especially, to fly UAV over the non-restricted airspace as a standard airworthiness standard, many authority funded research institutes and associations are studying regulatory environment. For the UAV to access civil airspace, the certification system of the aviation regulation have to allow this. FAA of US, CASA of Australia and European authorities are now issuing an experimental airworthiness certificate to a civil UAV. This is the first step of issuing a standard airworthiness certificate. And many people believe that civil UAV can fly over a NAS if some technical issues are resolved. In this study, I would like to present an international trends of a civil UAV regulation system, reliability trend of unmanned aerial system and would like to bring up a our regulatory environment and suggest an UAV regulatory policy.

• Journal of Soil and Groundwater Environment
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• v.15 no.2
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• pp.18-23
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• 2010

Usability of soil quality monitoring network for ascertaining soil quality changes was evaluated by analysing soil quality monitoring results. Tolerance limits of soil quality monitoring results from 1997 to 2007 were calculated and compared with Korean soil quality standards. This study determined that soil quality was changed if the upper 95% tolerance limit value was greater than the soil quality standard. Fluoride most frequently exceeded the soil quality standard and nickel, zinc, arsenic, copper, lead and cadmium were followed. Analysis on land use showed that tolerance limits of industrial land use most frequently exceeded the soil quality standards and residential, road and various land uses then frequently exceeded. Tolerance limits of land uses expecting high contaminant loads frequently exceeded the soil quality standards. This fact imply that the soil quality monitoring network generates reasonable data to represent change in Korean soil quality. This study also suggested that representative sampling from well identified points should be done to improve data reliability and accurately ascertain soil quality changes.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1772-1777
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• 2004

The performances of the newly constructed Stereoscopic PTV and Stereoscopic PIV which had been completed based on a 3D-PTV principle are tested using the Standard Images. Virtual images were produced for the benchmark tests of the constructed two Stereoscopic techniques. The arrangement of the two cameras was based on angular position. The calibration of cameras and the pair-matching of the three-dimensional velocity vectors were based on Genetic Algorithm based 3D-PTV technique. The Standard data of LES are on the impinged jet proposed by VSJ. It is shown that the results obtained by Stereoscopic PTV have better reliability than those by Stereoscopic PTV.

• Journal of Korean Society of Water and Wastewater
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• v.11 no.3
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• pp.87-95
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• 1997

A river water quality management model was made by Dynamic programming. This model optimizes the wastewater treatment cost of the application area, and computed water quality with it must meet the water quality standard. And this model takes into consideration tributary input, wastewater treatment plant effluent, withdrawls for several purposes. Modified Streeter-Phelps equation was used to calculate BOD and DO. Optimization problem was solved with particular exceedance probability flow, and the water quality of each point was calculated with the decided treatment efficiencies. At that time, the probability satisfying the water quality standard of constraints to the exceedance probability of the flow. The developed model was applied to the lower part of the Han-River. The reliability to meet the water quality standard is 70 % when 4 wastewater treatment plants of Seoul City are operated by activated sludge system at autumn of the year 2001. Treatment cost of this case is 121.288 billion won per year.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.226-227
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• 2019

Installation and usage methods are currently different between China and Korea for the same rubber asphalt waterproofing sealant. Quality verification is not properly carried out in this situation, so it is necessary to secure reliability in order to export domestic materials to China. In this study, rubber asphalt waterproofing sealant used as injection-type leakage repair material was tested in accordance to adhesion strength quality test method outlined in the JC/T2428 Chinese Industrial Standard to confirm the basic performance is compliant or not.

• Hwankyungkyoyuk
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• v.24 no.4
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• pp.32-40
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• 2011

The purpose of this study was to develop an evaluation standard by which teachers in charge of environment and green growth education could conduct a project activity and examine its applicability. The results were as follows; First, 26 evaluation items were developed through interviews with teachers and expert meetings. These categories were base on 'Theme', 'Planning', 'Result' and 'Presentation', and 'Evaluation' of the project. Second, a reliability test showed that internal consistency of the items was currently high(Cronbach's alpha .8709). To examine the content validity, the project activity was evaluated by 5 different teachers, and the result showed that the evaluation standard developed in this study was a very effective tool for the teachers to do project learning. Third, from the 2011 revised national curriculum, the subject 'Environment' in middle schools would be renamed as 'Environment and Green Growth'. Also, environment project activity would be introduced in the middle school. Therefore, this study had a significant importance in the fact that it provided teachers and students with a practical evaluation standard for the environment and green growth project activity.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.8
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• pp.53-62
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• 1995

In recent years, the rapid development of the machine tool and tough insert has made metal removal rates increase, and automatic system without human supervision requires a higher degree reliability of machining process. Therefore the control of chips is one of the important topics which deserves much attention. The chip classification was made based upon standard deviation of the mean cutting force measured by a tool dynamometer. STS304was chosen as the workpiece which is known as the difficult-to-cut material and mainly saw-toothed chip produced, and the chip type according to the standard deviation of mean cutting force was classified into five categories in this experiment. Long continuous type chip which interrupts the normal cutting process, and damages the operator, tool and workpiece has low standard deviation value, while short broken type chip, which is favourable chip for disposal, has relatively large standard deviation value. In addition, we investigated the possibility that the chip type can be predicted analyzing the relationship between chip type and cutting condition by the trained neural network, and obtained favourable results by which the chip type can be predicted with cutting conditon before cutting process.

• New & Renewable Energy
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• v.20 no.1
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• pp.95-101
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• 2024

Since 1990, the Renewable Big Data Research Lab at the Korea Institute of Energy Technology has been observing solar radiation at 16 sites across South Korea. Serving as the National Reference Standard Data Center for Renewable Energy since 2012, it produces essential data for the sector. By 2020, it standardized meteorological year data from 22 sites. Despite user demand for data from approximately 260 sites, equivalent to South Korea's municipalities, this need exceeds the capability of measurement-based data. In response, our team developed a method to derive solar radiation data from satellite images, covering South Korea in 400,000 grids of 500 m × 500 m each. Utilizing satellite-derived data and ERA5-Land reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF), we produced standard meteorological year data for 1,000 sites. Our research also focused on data measurement traceability and uncertainty estimation, ensuring the reliability of our model data and the traceability of existing measurement-based data.

• Industry Promotion Research
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• v.8 no.1
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• pp.111-117
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• 2023

Sampling inspection methods for quality control have been proposed a lot in the industry. However, the sampling inspection method for reliability, which is a quality over time, has been relatively less presented, and there are not many literatures that are clearly summarized. Therefore, this paper focuses on the reliability conformity test to verify that the reliability evaluation scale value of the target is satisfied during the reliability test. To this end, first, we look at the conditions that both consumers and producers can satisfy in terms of the OC curve and find out what sampling methods satisfy the desired level of producer risk and consumer risk. Next, two methods of the reliability sampling methods such as attribute and variable reliability sampling methods are examined. Specifically, the attribute reliability sampling method is a form of sampling plan where n samples are tested for a certain period of T hours and the lot is accepted if the number of failures is less than or equal to a certain number c. On the other hand, the variable reliability sampling method is a form of sampling plan where the lot is accepted if the reliability evaluation scale such as MTBF satisfies a certain standard. Both sampling plans may also use inspection tables.