• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3852-3859
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• 2021

This paper presents experimental and numerical analysis results regarding the effects of an incomplete penetration defect on the fatigue lives of socket welded pipes. For the experiment, four-point bending fatigue tests with various defect geometries (defect depth and circumferential length) were performed, and test results are presented in terms of stress-life data. The results showed that for circumferentially short defects, the fatigue life tends to increase with increasing crack depth, but for longer defects, the trend becomes the opposite. Finite element analysis showed that for short defects, the maximum principal stress decreases with increases in crack depth. For a longer defect, the opposite trend was found. Furthermore, the maximum principal stress tends to increase with an increase in defect length regardless of the defect depth.

• The KIPS Transactions:PartD
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• v.10D no.4
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• pp.709-718
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• 2003

This research introduces defect and its causes that happen on software development. Based on defect cause analysis, we understand associated relation between defects and them design defect trigger. So, when we achieve similar project, we can forecast defect and prepare to solve defect by using defect trigger.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05a
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• pp.225-228
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• 2010

It is an social issue that is various claim related on the defect of apartment house. The cost of defect repair is the most important matter that residents dispute constructers with the huge time wasting and cost loss. For resolve the matter of defect claim, it must to be analyze to the cost property that study and find to pending issue about the cost of defect repair. Therefore this study is investigated the cost property of defect repair relation on correlation analysis and regression analysis around the judgement cost. Consequently, cost of the judgment is associated with cost of the accusation and cost of the defect repair, is recognizable as them that is closely connected. Meanwhile, the more time of take effect and time of lawsuit increase, the more cost of the judgment decrease by draw the regression equation. On the contrary, there are same aspects in the case on the cost of the accusation and cost of the defect repair.

• The KIPS Transactions:PartD
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• v.11D no.4
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• pp.873-884
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• 2004

This research provides the solution of defect problem and detection of defect and its causes that happen on software development. For developing a reliable software, a key factor is to find and manage defects that are during software development. Based on defect items analysis, we understand associated relation between defects and design defect opportunity tree. Developing the similar project, we can estimate defect and prepare to solve defect by using defect management opportunity tree.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.166-167
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• 2013

There has been a defect dispute of apartment building in Korea. The defect dispute is complicated by main issues and details of dispute. It is yet to be solved. Meanwhile, a judge does not a inspection and analysis, but, related field expert who contracted professional engineer does. As a result, defect consulting report that an important judgment is used in a defect dispute. Therefore, this study does research on structure of defect consulting report. A defect consulting report has same items, irrespective of a defect consultant as a result that check 7 indexes about 10 cases. It has different structure's details depending on each defect consultants. And, it inserts new detail or deletes existing detail, does not show clear distinction.

• Journal of the Korean Society of Safety
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• v.18 no.4
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• pp.28-34
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• 2003

In the present study, three-dimensional finite element analysis was performed to investigate the effects of internal wall thinning defect on the failure pressure of elbow in the piping system and to develop the failure pressure evaluation model. From the results of finite element analysis, the failure pressure was derived by employing local stress criteria, and the effects of thinning location, bend radius, and defect geometry on the failure pressure of internally wall thinned elbow were investigated. Also, based on these investigations and previous model developed to estimate the failure pressure of elbow with an external pitting defect, the failure pressure evaluation model to be applicable to the elbow containing an internal thinning defect was proposed and compared with the results of finite element analysis. The failure pressure calculated by the model agreed well with the results of finite element analysis.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.333-336
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• 2008

The groove rolling is a process that transforms the bloom or billet into a shape with circular section through a series of rolling. Inhibition of surface defect generation in groove rolling is a matter of great importance and therefore many research groups proposed a lot of models to find the location of surface defect initiation. In this study, we propose a model for maximum shear stress ratio over equivalent strain to catch the location of surface defect onset. This model is coupled with element removing method and applied to box groove rolling of POSCO No. 3 Rod Mill. Results show that proposed model in this study can find the location of surface defect initiation during groove rolling when finite element analysis results is compared with experiments. The proposed criterion has been applied successfully to design roll grooves which inhibits the generation of surface defect.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.6
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• pp.259-263
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• 2001

The continuum model of transient point defect dynamics to predict the concentrations of interstitial and vacancy is established by estimating expressions for the thermophysical properties of intrinsic point defects. And the point defect distribution in a Czochralski-grown 200 mm silicon crystal and the location of oxidation-induced stacking fault ring(OiSF-ring) created during the cooling of crystals are calculated by using the numerical analysis. The purpose of this paper is to show that his approach lead to predictions that are consistent with experimental results. Predicted point defect distributions by transient point defect dynamic analysis are in good qualitative agreement with experimental data under widely and abruptly varying crystal pull rates when correlated with the position of the OiSF-ring .

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.2
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• pp.215-223
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• 2021

The domestic CANDU nuclear power plants have been operated for a long time and various unforeseen spent fuel defects have been discovered. As the spent fuel defects are important factors in the safety of the nuclear power plant, a study on the analysis of the spent fuel defects to prevent their recurrence is necessary. However, in cases where the fuel rods inside the fuel assembly are defected, it is difficult to dismantle the fuel assembly owing to their welded structure and the facility conditions of the plant. Therefore, it is impossible to analyze the spent fuel defect because it is difficult to visually check the shape of the fuel defect. To resolve these problems, an analysis technology that can predict the number of defected fuel rods and defect size was developed. In this study, we developed a methodology for investigating the root cause of spent fuel defects using a database of the earlier fuel defects in the plants. It is anticipated that in the future this analysis technology will be applied when spent fuel defects occur.

• Journal of the Korea Institute of Building Construction
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• v.13 no.5
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• pp.498-505
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• 2013

The main processes involved in a defect dispute are consulting, reviewing, and finally judging as an arbiter. This process of defect consulting produces a defect consulting report, but business practices and standards of judgment will differ among consultants, and have many problems. This study reviews the structure of a defect consulting report and considers the structure's problem, which is that it is not standardized. To achieve this, data of sixteen defect consulting report were collected involving defect lawsuit cases before or after 2010. The structure and index of the defect consulting reports were then reviewed, and the results are as follows. As for a structure based on fourteen index, there are suitable that judge a outline, a cost estimate data and a consulting work item by a consulting standard. Furthermore, analysis by each common parts and private parts is considered as appropriate about consulting items and estimate by standard. However, consulting item in construction progress and responsibility period for security that related on a cause and a responsibility of defect need to complement. Meanwhile, the first thing of issues are connected a defect consulting is urgent a standardization for a defect type.