• Title/Summary/Keyword: Defects

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MITIGATION AND REMISSION OF CONTRACTOR'S DEFECTS LIABILITY IN KOREAN CONSTRUCTION CONTRACTS

  • Jong-Gwang Lee ;Yong-Su Kim
    • International conference on construction engineering and project management
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    • 2005.10a
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    • pp.447-451
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    • 2005
  • The purpose of this study is to improve regulations such as law and standard contract forms related to defects liability in Korea. Defects liability has been one of the major causes of construction contract disputes in Korea in recent years. It is important to avoid or resolve disputes regarding defects liability through regulations containing clear criteria and to specify the standard regarding the mitigation and remission of the contractor's defects liability. This study was carried out through document research and analysis of judicial precedents. The following are the courses of improvement regarding the mitigation and remission of defects liability in Korea. First, laws and standard contract forms must contain more detailed clauses regarding exemption of a contractor's defects liability, which clearly set out the scope of the defects liability of the contractor. Second, the current system for defects liability favors the owner rather than the contractor - it is necessary to change the defects liability system in order to give the owner and the contractor an equal standing. Third, strict liability is taken on by the contractor even when the term of guarantee for defects lasts longer than the legally set period of liability for defects. Hence, it is necessary to improve the system by alleviating the liability of the contractor through applying negligence liability as opposed to strict liability during the term of guarantee.

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The Effect of Domain Wall on Defect Energetics in Ferroelectric LiNbO3 from Density Functional Theory Calculations

  • Lee, Donghwa
    • Journal of the Korean Ceramic Society
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    • v.53 no.3
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    • pp.312-316
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    • 2016
  • The energetics of defects in the presence of domain walls in $LiNbO_3$ are characterized using density-functional theory calculations. Domain walls show stronger interactions with antisite defects than with interstitial defects or vacancies. As a result, antisite defects act as a strong pinning center for the domain wall in $LiNbO_3$. Analysis of migration behavior of the antisite defects across the domain wall shows that the migration barrier of the antisite defects is significantly high, such that the migration of antisite defects across the domain wall is energetically not preferable. However, further study on excess electrons shows that the migration barrier of antisite defects can be lowered by changing the charge states of the antisite defects. So, excess electrons can enhance the migration of antisite defects and thus facilitate domain wall movement by weakening the pinning effect.

A Video based Web Inspection System for Real-time Detection of Paper Defects during Papermaking Processes (제지공정의 실시간 결함 검출을 위한 영상 기반 웹 검사 시스템)

  • Hahn, Jong-Woo;Choi, Young-Kyu
    • Journal of the Semiconductor & Display Technology
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    • v.9 no.2
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    • pp.79-85
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    • 2010
  • In this paper, we propose a web inspection system (WIS) for real-time detection of paper defects which can cause critical fractures during papermaking process. Our system incorporates high speed line-scan camera, lighting system, and detection algorithm to provide robust and precise detection of paper defects in real-time. Since edge defects are very crucial to the paper fractures, our system focuses on the edge region of the paper instead of inspecting the whole paper area. In our algorithm, image projection and sub-pixel operation are utilized to detect the edge defects precisely and connected component labeling and shape analysis techniques are adopted to extract various kinds of the region defects. Experimental results revealed that our web inspection system is very efficient for detecting paper defects during papermaking processes.

Analysis and Depth Estimation of Complex Defects on the Underground Gas Pipelines

  • Kim, Jong-Hwa;Kim, Min-Ho;Choi, Doo-Hyun
    • Journal of Magnetics
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    • v.18 no.2
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    • pp.202-206
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    • 2013
  • In this paper, the MFL (magnetic flux leakage) signals of complex defects on the underground gas pipeline are analyzed and their depths are estimated. Since closely-located defects (complex defects) affect each other, accelerate the progress of defection, and are finally combined to one (cluster), it's meaningful to differentiate complex defects from single defects by analyzing their characteristics. Various types of complex defects are characterized and analyzed by defining the safety distance for interference. 26 artificial defects are carved on the pipeline simulation facility (PSF) to analyze the characteristics of complex defect and demonstrate the accuracy of the proposed complex defect estimation. The proposed method shows average length error of 5.8 mm, average width error of 15.55 mm, and average depth error of 8.59%, respectively.

A Study on The Visual Inspection of Fabric Defects (시각 장치를 이용한 직물 결함 검사에 관한 연구)

  • Kyung, Kye-Hyun;Ko, Myoung-Sam;Lee, Sang-Uk;Lee, Bum-Hee
    • Proceedings of the KIEE Conference
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    • 1988.07a
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    • pp.959-962
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    • 1988
  • This paper describes an automatic visual inspection system for fabric defects based on pattern recognition techniques. The inspection for fabric defects can be separated into three sequences of operations which are the detection of fabric defects[1], the classification of figures of fabric defects, and the classification of fabric defects. Comparing projections of defect-detected images with the predefined complex, the classification accuracy of figures of fabric defects was found to be 95.3 percent. Employing the Bayes classifier using cluster shade in SGLDM and variance in decorrelation method as features, the classification accuracy of regional figure defects was found to be 82.4 percent. Finally, some experimental results for line and dispersed figures of fabric defects are included.

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Effects of Post Annealing and Oxidation Processes on the Shallow Trench Etch Process (Shallow Trench 식각공정시 발생하는 결함의 후속열처리 및 산화곤정에 따른 거동에 관한 연구)

  • 이영준;황원순;김현수;이주옥;이정용;염근영
    • Journal of the Korean institute of surface engineering
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    • v.31 no.5
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    • pp.237-244
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    • 1998
  • In this stydy, submicron shallow trenches applied to STI(shallow tench isolation) were etched using inductively coupled $CI_2$/HBr and $CI_2/N_2$plasmas and the physical and electrical defects remaining on the etched silicon trench surfaces and the effects of various annealing and oxidation on the removal of the defects were studied. Using high resolution electron microscopy(HRTEM), Physical defects were investigated on the silicon trench surfaces etched in both 90%$CI_2$/ 10%$N_2$ and 50%$CI_2$/50%HBr. Among the areas in the tench such as trench bottom, bottom edge, and sidewall, the most dense defects were found near the trench bottom edge, and the least dense defects were found near the trench bottom edge, and least dense defects compared to that etched with ment as well as hydrogen permeation. Thermal oxidation of 200$\AA$ atthe temperature up to $1100^{\circ}C$apprars not to remove the defects formed on the etched silicon trenches for both of the etch conditions. To remove the physicall defects, an annealing treatment at the temperature high than $1000^{\circ}C$ in N for30minutes was required. Electrical defects measured using a capacitance-voltage technique showed the reduction of the defects with increasing annealing temperature, and the trends were similar to the results on the physical defects obtained using transmission electron microscopy.

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Proposal of Checklist for the Management of Defects in Barracks Facilities (병영시설 하자관리를 위한 체크리스트 제안)

  • Kim, Jeong-Seop;Bang, Hong-Soon;Kim, Ok-Kyue
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2022.04a
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    • pp.41-42
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    • 2022
  • The management of defects in barracks facilities is carried out in such a way that defects found by the facility's manager are listed and requested to be repaired by the contractor. However, the standards and methods for the inspection of defects in the management of these defects are not specified in detail, so it is difficult to check the defects in detail. In response, the study first analyzed the current status of the number of defects that occurred in 2021 at official residences and barracks of certain units. As a result of the analysis, the number of defects that were not taken care of and that were not taken until the previous month was more than 10 cases on average per month. In order to reduce the number of such defects, major improvements in the field, timing, and safety inspection were found after the inspection of the military's facilities and safety, and the analysis of the manual of maintenance management. In addition, items for improvement of the checklist were derived through an analysis of the repair of defects caused by the unit's official residence and a total of 10 barracks facilities. Based on this, a checklist was proposed to manage defects in barracks facilities through interviews with military facility managers.

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Selection of Tree History Management System Items for Analyzing the Causes of Landscape Tree Defects in an Apartment Complex

  • Park, Sang Wook
    • Journal of People, Plants, and Environment
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    • v.23 no.3
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    • pp.347-362
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    • 2020
  • Background and objective: It is difficult to conclusively determine the exact cause of tree defects since multiple causes are involved such as climate change, plantation, tree quality and planting time, construction, planting base, drainage, sunshine conditions, maintenance, and microclimate. The data related to landscaping construction defects are scattered or fragmented by companies and years, but not managed systematically by the defect information management system. Most of the earlier studies associated with tree defects in apartment complexes suggested defect rates after examining tree defects in the completed construction site and proposed fragmentary and subjective conclusions about the causes of defects observed in trees with high defect rates. It is proposed to continue to conduct studies on the establishment and analysis of systematic databases to identify the exact causes of tree defects and measures to improve, and the need to accumulate systematic data in the construction process where many defects arises. This study was conducted to reduce the defects of trees planted in apartment complexes. Methods: Main factors related to tree defects were subdivided based on the results of literature review and a defect investigation at the completion site, and tree history management items were selected and subdivided during the construction stage. Results: The criteria for the preparation of subdivided items were obtained, and the tree history management checklist was written for the site under actual construction and a systematic database was established. Items that are categorized based to the causes of defects include the location of nurseries, date, tree quality, site conditions, planting techniques, microclimates, and maintenance. Conclusion: This study suggested tree history management items based on the tree defects that can be identified at the construction stage and applied them to the selected study site, which differentiates this study from earlier studies. It will be necessary to conduct a comprehensive and objective time series analysis on tree defects that occur over time by continuously monitoring and collecting data after construction.

An Analysis of Defects Apartment Houses Occurring during the Term of Warranty Liability (하자담보책임기간에 발생하는 공동주택 하자 분석)

  • Yu, Byong-Jae;Bang, Hong-Soon;Kim, Ok-Kyue
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2022.11a
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    • pp.135-136
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    • 2022
  • Defects caused by apartment houses have the term of warranty liability according to the enforcement ordinance of Acts of the Management of Apartment Houses. In case when defects occur during the term, free defect maintenance can be provided from the construction company. Yet, there occur conflicts between the construction company and residents, as to whether there occur defects or not. To resolve these conflicts, this study aimed to analyze construction classification and types that need managing, based on defects of apartment houses occurring during the term of warranty liability. This research analyzed 138,576 cases of data, as of five apartment house complexes. For the construction classification for defects of apartment houses, wooden flooring products accounted for the highest rate, followed by paper hanging, and wooden window. For the construction types of defects, torn/scratching took up with the highest rate, followed by the condition of defect in fixing and operating. In order to embody defects occurring during the term of warranty liability, into the visualization technique, this researcher utilized the word cloud method. This study will pursue the method for maintaining defects during the term of warranty liability, in the subsequent research, using the data that this research presented.

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Approximated 3D non-homogeneous model for the buckling and vibration analysis of femur bone with femoral defects

  • Mobasseri, Saleh;Sadeghi, Mehdi;Janghorban, Maziar;Tounsi, Abdelouahed
    • Biomaterials and Biomechanics in Bioengineering
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    • v.5 no.1
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    • pp.25-35
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    • 2020
  • We carry the knowledge that the skeleton bones of the human body are not always without defects and some various defects could occur in them. In the present paper, as the first endeavor, free vibration and buckling analysis of femur bones with femoral defects are investigated. A major strength of this study is the modeling of defects in femur bones. Materialise Mimics software is adopted to model the bone geometry and the SOLIDWORKS software is used to generate the defects in bones. Next, the ABAQUS software is employed to study the behaviors of bones with defects.