• 한국신뢰성학회지:신뢰성응용연구
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• 제11권3호
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• pp.235-244
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• 2011

Hydraulic hose assemblies deliver a fluid power in various oil pressure equipment such as construction machinery, automobile, aircraft, industrial machinery, machine tools and machinery for ships. Also, they are widely used as pipes in oil pressure circuit. When we estimate their lifetime, it is essential to conduct an accelerated life test by choosing the factor that suits the usage condition of the test object since traditional test method for estimating lifetime under the influence of various external factors incurs hardship in terms of time and expenses. The objective of this study is to propose an acceleration model that takes both temperature and pressure without flexing condition into consideration. The lifetime is estimated by applying the proposed temperature-nonthermal acceleration model to the test data. And we compare the proposed temperature-nonthermal acceleration model and the accelerated life equation suggested by John(1994).

• 한국항해항만학회지
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• 제43권5호
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• pp.310-319
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• 2019

With the recent increase in the volume of liquid cargo transportation, there is a need for STS( Ship To Ship) globally. In the case of the STS mooring, the safety assessment should be conducted according to other criteria because mooring is different from the general mooring at the quay, but there is no separate standard in Korea. Thus in this study, STS mooring simulation and sensitivity analysis using OPTIMOOR program, the numerical analysis program, was conducted to identify the characteristics of the STS mooring. The target sea modeled the Yeosu port anchorage in Korea and the target ship was selected as the case of VLCC (Very Large Crude Oil Carrier)-VLCC. Through the numerical simulation and sensitivity analysis, the characteristics of STS mooring were identified. Also based on these results, we focused on establishing the standard for STS mooring safety assessment. Numerical simulation results show that the STS mooring safety can be changed according to a ship's cargo loading condition, pre-tension of mooring line, sea depth, encounter angle with the weather, and the weather condition. Additionally, the risk matrix is prepared to establish the safe external force range in the corresponding sea area. This result can be used to understand the mooring characteristics of STS and contribute to the revision of mooring safety assessment criteria.

• 한국정밀공학회지
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• 제20권8호
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• pp.158-165
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• 2003

The object of this work is to develop an assessment system for pipeline integrity. The internal algorithm and the database of the system are described in this paper. The system consists of four module applications; the effect of corrosion in pipeline, crack, SCC (stress corrosion cracking) and fatigue module. The database of the system is separated to mainly four parts; geometry of pipeline, material properties, boundary condition and general properties. This system may give a guideline for maintenance and modifications.

• 한국안전학회지
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• 제20권4호
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• pp.71-77
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• 2005

There are insufficient models that find problems and solutions for accident prevention through risk assessment and suggest safe work process and work instruction from foundation works to finish work for accident decrease. This paper presents a quantitative risk assessment model by analysis of risk factors in each process such as foundation, erection, structure, equipment finish and etc based on accident examples and investigation on actual condition in building. In addition, the safety management system was developed to perform risk assessment of construction and use it for effective safety training for labor.

• 대한안전경영과학회지
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• 제16권3호
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• pp.273-277
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• 2014

Subcontracting business than the contracting business in shipbuilding industry is a lot of hazardous job and highly accident because of highly work intensity. In order to prevent the accidents, there is a need to analyze characteristic. of shipbuilding, to apply measures of risk assessment. In this paper, I suggested an improvement of the risk assessment through the actual condition research in shipbuilding industry. In the research method, I analysed accidents occurred until 2011-2013. Carried out the actual site survey while two weeks in May 2014. As a result, 1) The main pattern were caught-in or between, fall on the high level according to analyzed accidents. 2) To apply the weight show clear of magnitude for risk assessment. 3) Risk estimation of risk assessment is desirable to be quantization by accidents analysis, and to be greater than or equal to 4 steps.

• 한국초등과학교육학회지:초등과학교육
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• 제18권1호
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• pp.41-51
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• 1999

The purpose of this study was to Investigate about current status of authentic science performance assessment in elementary schools. A total of 707 elementary teachers was involved and the data from questionnaire was gathered. The questionnaire was comprised two categories: items on the epistemological aspect & items on the actual condition. The major findings are as follows: 1. There are some elementary teachers who don't have a clear understanding on what authentic science performance assessment is even though most of teachers admit the importance of authentic performance assessment in their science teaching. 2. Malty teachers have chosen and have used experimental activities or performance tasks rather than they have developed tasks of their own. 3. Malty teachers have pointed out 'tile lack of time for performance assessment preparation' and 'the limitation of class time' as tile problems of working on science performance assessment in elementary schools.

• 한국환경보건학회지
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• 제44권5호
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• pp.460-467
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• 2018

Objectives: The objectives of this study are to estimate the inhalation exposure level of benzene for workers using Tier 1 exposure models ECETOC TRA (European Center for Ecotoxicology and Toxicology of Chemicals Target Risk Assessment) and Stoffenmanager, and to investigate their reliability for exposure assessment in K-REACH. Methods: Two exposure scenarios, 'manufacture of benzene' and 'use as solvents,' were developed for assessment of workers' exposure to benzene. The Process Category (PROC) for ECETOC TRA was collected from the European Chemical Agency (ECHA) registration dossier, and the Activity for Stoffenmanager was converted from PROC using translation of exposure models (TREXMO). The information related to exposure, such as working duration, Respiratory Protective Equipment (RPE), Local Exhaust Ventilation (LEV), and Risk Management Measure (RMM) were classified into high, medium, and low exposure conditions. The risk was determined by the ratio of the estimated exposure and occupational exposure limits of benzene. Results: Under high exposure conditions, the worker exposure level calculated from all PROCs and Activities exceeded the risk level, with the exception of PROC 1 and Activity 1. In the medium exposure condition, PROC 8a, 8b, and 9 and Activity 3, 7, and 8 all exceeded the risk, whereas in the low condition, all PROCs and Activities were determined to be safe. As a result, action corresponding with the low exposure condition is required to reduce the risk of exposure among workers in workplaces where benzene is manufactured or used as a solvent. In addition, the predicted exposure levels derived from the exposure models were lower than measured levels. The exposure levels estimated from Stoffenmanager were more conservative than those from ECETOC TRA. Conclusions: This study demonstrates the feasibility of exposure models for exposure assessment through the example of occupational inhalation exposure assessment for benzene. For more active utilization of exposure models in K-REACH, the exact application of collected information and accurate interpretation of obtained results are necessary.

• 대한환경공학회지
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• 제27권10호
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• pp.1090-1098
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• 2005

벤조일 퍼록사이드는 수서생물에 대해 매우 높은 독성을 나타냄에도 불구하고 환경 중 잔류 농도 및 노출영향에 대해 연구가 이루어지지 않아 OECD에서 추천하고 있는 대표적인 다매체 환경거동 모델인 EQC 모델을 이용하여 본 물질에 대한 환경중의 농도를 예측하고 위해성평가 및 화학물질의 관리를 수행하기 위한 기초자료로 활용코자 하였다. 평형, 정상상태에서 100,000 kg의 벤조일 퍼록사이드가 환경내로 유입된 상태를 나타내는 Level I과 평형, 정상상태 이류와 분해현상이 있고 일정한 속도 1,000 kg/h로 유입되었을 경우를 나타내는 Level II에서 벤조일 퍼록사이드는 주로 토양(68.3%)과 물(28.7%)로 배출되는 것으로 예측되었다. 비평형, 정상상태, 이류와 분해현상이 있고 다매체 이동을 하는 시스템에서 벤조일 퍼록사이드가 대기, 물, 토양, 침전물의 각각의 4개 매체에 연속적으로 1,000 kg/h로 유입될 경우인 Level III에서는 주로 토양(99.9%)으로 배출되었고 전체 잔류시간은 3.4년으로 예측되어 벤조일 퍼록사이드가 환경 중에 잔류성이 있는 물질로 평가되었다.

• 환경영향평가
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• 제21권2호
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• pp.247-254
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• 2012

This paper seeks for the set-up plan in the reasonable target area of environmental assessment. Domestically, the target area of environmental assessment is set up by the adjustment of opinion collection about the assessment scope result of an environmental factor. In a foreign country, the boundary of the target area for a development project is established with the environmental, economical, and social viewpoint based on the standard for significantly environmental impact. Based on the analysis of the present condition at home and abroad, the first set-up plan for the reasonable target area of environmental assessment is the preparation of the detailed term definition related to the target area of environmental assessment. The second is the arrangement of the judgement standard for significantly environmental impact. The quantitative assesment item can apply the present standard or regulation, and the qualitative assessment item can establish the standard based on factual and objective data. The last is the preparation of the reference material or the guideline for deciding the initial target area by the judgement standard and determining the final target area by opinion collection in the stage of scoping.

• 한국환경복원기술학회지
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• 제17권4호
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• pp.57-67
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• 2014

The vigor condition of trees is an important indicator for the management of urban forested area. But difficulties in how to assess the tree vigor condition still remain. Previous efforts were limited in the 1) measurement of single indicator rather than using multiple indices, 2) purpose-oriented measurement such as for air-pollution effect or specific pathological symptom, and 3) ordinal-scale evaluations by field crews 4) despite human errors based on his/her experiences or prior knowledge. Therefore, this study attempted to develop a quantitative and objective methodology for assessing tree vigor condition, by measuring multiple modules and building the profile inventory. Furthermore, the possibility and limitations were discussed in terms of schematic frames describing tree vigor condition. The vigor condition of 56 flowering cherry plants in urban park were assessed by in-situ measurements of following eight items; growth of crown(Gc), growth of shoots, individual tree volume(Vol), plant area index, woody area index, leaf area index, leaf chlorophyll content(Lc) and leaf water content(Lw). For validation, these measurements were compared with the ranks of holistic tree vigor condition, which were visually assessed using a 4-point grading scale based on the expert's knowledge. As a result, the measures of each evaluation item successfully highlighted a variety of aspects in tree vigor condition, including the states of both photosynthetic and non-photosynthetic parts. The variation in the results depending on evaluated parts was shown within an individual tree, even though the broad agreement among the results was found. The result of correlation analysis between the tested measurements and 4-point visual assessment, demonstrated that the state of water-stressed foliage of the season (Lw) or the development of plant materials since sapling phase (Vol) could be better viewed from the outer appearance of trees than other symptoms. But only based on the visual assessment, it may be difficult to detect the quality of photosynthesis (Lc) or the recent trend in growth of trees (Gc). To make this methodology simplified for the broad-scale application, the tested eight measurements could be integrated into two components by principal component analysis, which was labelled with 'the amount of plant materials' and 'vigor trend', respectively. In addition, the use of these quantitative and multi-scale indicators underlies the importance of assessing various aspects of tree vigor condition, taking into account the response(s) on different time and spatial scale of pressure(s) shown in each evaluated module. Future study should be advanced for various species at diverse developing stages and environment, and the application to wide areas at a periodic manner.