• Title/Summary/Keyword: Maintenance and Repair

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The Study on the Correlation between Value Recognition and Urban Design Policy on the Urban Street - Focused on the Spatial Changes in Seoul during the Modern Periods - (도시공공환경의 변인으로서 사회가치인식과 제도의 변화상에 관한 연구 - 근대기 서울의 도시가로환경에 관한 담론을 중심으로 -)

  • Lee, Ji-Young
    • Korean Institute of Interior Design Journal
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    • v.22 no.3
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    • pp.164-173
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    • 2013
  • This study starts from the genealogical analysis of the urban public spaces through local history of Seoul which is significantly different from western countries. The analysis targets the discourse on the urban street, the basic unit of urban tissue and the settlement condition in urban life, which defines urban space-structure among the urban public spaces. And this research classifies and categorizes the value recognition and policy value occurred each period. Based on these, this research defines the progress levels of urban public design policy in Seoul as follows. Results Firstly, 1890's and 1900's was the period of development in commerce and industry, which caused congested and crowded streets. The open port policy allowed the experience of the foreign circumstance, and thus the identity of the urban streets and the value of symbolism come to realize among the society. During the Japanese colonization, urban streets put on modernized images through the urban remodeling out of the context according to the colonization policy. The brand-new values such as publicness and amenity are injected as well as modern regulations by system and authority. From Liberation to 1950's, it performed only street restoration as a repair from war with Japanese colonial system because of the political confusion and administrative vacuum. Finally, each period can be defined as follows. 1890's and 1900's can be defined as 'spontaneous finding the modernization' because urban street was intentionally transformed by the empire. Period of the Japanese colonization can be defined as 'the formation of modernized urban street concept and the compulsion of modernized regulation.' And period of from Liberation to 1950's, can be called as 'the absence of value recognition and maintenance of colonial system.' methodology.

RIGID FIXATION AND SPACE MAINTENANCE BY TITANIUM MESH FOR RECONSTRUCTION OF THE PREMAXILLA (상악골 전방 결손부 재건 시 견고 고정과 공간 유지로 사용된 타이타니움 메쉬의 임상 예)

  • Lee, Eun-Young;Kim, Kyoung-Won;Choi, Hee-Won;Koh, Myoung-Won
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.27 no.1
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    • pp.85-92
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    • 2005
  • Reconstruction of defect in the anterior part of the maxilla to enable implant placement or prothesis is a complicated treatment due to the anatomical position and lack of soft tissues. Two cases are presented in which autogenous iliac PMCB(particulate marrow and cancellous bone) with titanium mesh were used for premaxilla reconstruction and alveolar bone repair of the anterior maxillas prior to denture and implants fixation respectively. Cancellous bone from the anterior iliac crest was compressed and placed against a titanium mesh fixed to the bone of palate in a patient with severe defect of the anterior maxilla. There were no problem in the healing, and the anterior maxillas of two patients had increased height and width during the initial healing and remodeling. The clinical reports describe the use of titanium mesh for reconstruction of premaxilla. Autogenous bone grafts were harvested from the iliac crest and were loaded on a titanium mesh that were left in the patient's maxilla for 6 months before they were removed respectively. The radiographic analysis demonstrated that a 10mm vertical ridge augmentation had been achieved. In guided bone regeneration, the quantity of bone regenerated under the barrier has been demonstrated to be directly related to the amount of the space under the membrane. This space can diminish as a result of membrane collapse. To avoid this problem which involved the use of a titanium mesh barrier to protect the regenerating tissues and to achieve a rigid fixation of the bone segments, were used in association with autologous bone in 2 cases. The aim of this study was to evaluate the capability of a configured titanium mesh to serve as a mechanical and biologic device for restoring a vertically defected premaxilla.

Suppression of Ku80 Correlates with Radiosensitivity and Telomere Shortening in the U2OS Telomerase-negative Osteosarcoma Cell Line

  • Hu, Liu;Wu, Qin-Qin;Wang, Wen-Bo;Jiang, Huan-Gang;Yang, Lei;Liu, Yu;Yu, Hai-Jun;Xie, Cong-Hua;Zhou, Yun-Feng;Zhou, Fu-Xiang
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.2
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    • pp.795-799
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    • 2013
  • Ku70/80 heterodimer is a central element in the nonhomologous end joining (NHEJ) DNA repair pathway, Ku80 playing a key role in regulating the multiple functions of Ku proteins. It has been found that the Ku80 protein located at telomeres is a major contributor to radiosensitivity in some telomerase positive human cancer cells. However, in ALT human osteosarcoma cells, the precise function in radiosensitivity and telomere maintenance is still unknown. The aim of this study was to investigate the effects of Ku80 depletion in the U2OS ALT cell line cell line. Suppression of Ku80 expression was performed using a vector-based shRNA and stable Ku80 knockdown in cells was verified by Western blotting. U2OS cells treated with shRNA-Ku80 showed lower radiobiological parameters (D0, Dq and SF2) in clonogenic assays. Furthermore, shRNA-Ku80 vector transfected cells displayed shortening of the telomere length and showed less expression of TRF2 protein. These results demonstrated that down-regulation of Ku80 can sensitize ALT cells U2OS to radiation, and this radiosensitization is related to telomere length shortening.

A Study on the Slope Stability Assessment of Seokguram Region in Gyeongju (경주 석굴암 주변 비탈면의 안정성에 관한 연구)

  • Lee, Kwang-Wu;Kim, Seung-Hyun;Cho, Sam-Deok
    • Journal of the Korean Geosynthetics Society
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    • v.16 no.4
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    • pp.139-149
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    • 2017
  • The maintenance, repair, and reinforcement projects and structural stability assessments of Seokguram have primarily focused on examining the condition of stone members of Seokguram and the concrete dome structure for Seokguram. However, a 12 m-high rock slope located behind Seokguram raises a concern of slope failure and rockfall, which may reduce stability of Seokguram. It is also unclear whether the soil slopes and masonry wall at the side and the front of Seokguram have sufficient long-term stability against localized heavy rains and earthquakes, which have been frequent in recent years. The present study investigates the ground and the slopes around Seokguram using detailed field survey to identify geographical and geological risk factors, and assess structural stability of the exposed rock mass behind and the slope in front of Seokguram and the masonry wall using stability analysis.

A Review of IOSS Design Standardization Technology for Aluminum Alloy Handrail of Offshore Platform

  • Kim, Yeon-Ho;Park, Joo-Shin;Shin, Hyun-Chang;Kim, Sung-Jun;Park, Dae-Kyeom;Ha, Yeon-Chul;Seo, Jung-Kwan
    • Journal of Ocean Engineering and Technology
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    • v.34 no.3
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    • pp.208-216
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    • 2020
  • The Integrated Offshore Standard Specification (IOSS) involves Korean shipyards, classification societies, research institutes, the Korean industrial society, engineering companies, and oil companies with the objective of reducing costs and risks without compromising safety in international offshore engineering procurement construction (EPC) projects using new standardized bulk components and qualification procedures. The activities of the IOSS include the analysis of the existing rules and regulations to achieve the best standardization, which is reflected in the best practices, and minimize the variables in regulations and rules. In addition, a standard inventory of shapes and dimensions, referred to as specifications, is proposed in the IOSS. In this paper, the aluminum tertiary standardization part (IOSS S102-1/2 S104: Specification for Structural Tertiary Design) is presented with the details of the procedures, background reviews, and cost-benefit analyses of the design and verification methods for standard designs in the IOSS standardization items. Based on the cost-benefit analysis, the application of standardized aluminum tertiary items to offshore projects has significant advantages in terms of maintenance and repair compared to the carbon steel tertiary items utilized in current industrial practices.

A Review on Recent Debate on Proposals of Amendment of the Article of Prohibition of Inhouse-Contract for Harmful Work in the Industrial Safety and Health Act (유해작업 사내도급 금지와 관련된 논란 및 개정방안에 관한 고찰)

  • Park, Doo Yong
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.24 no.1
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    • pp.1-13
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    • 2014
  • Objectives: The purpose of this study is to review the debate on the Article 28(Prohibition of Inhouse-Contract for Harmful Work) of the Industrial Safety and Health Law. Methods: Literatures and recent debate for prohibition and permission of inhouse-contract for harmful work were reviewed. Proposals of revision for the Article 28 of the Industrial Safety and Health Law were also reviewed. Results: It was not found reasonable to revise the Article 28 based on increased fatal accidents or diseases in the electroplating work and heavy metals handling works that are currently listed in the Presidential Decree under the law as the harmful works. Regulation types of prohibition or authorization for any harmful work shall have inherently poor coverage since the scope of application is extremely limited. Contractors for maintenance and repair of chemical facilities may not be included in the scope of application if the harmful works are defined as chemical handling works. If harmful works are prohibited, the contractor workers may loose their jobs. Therefore, it is necessary to consider balancing job security and occupational safety and health safety. Conclusions: Various limitations were found in the Article 28 and the proposals to revise it. Currently in-house subcontracting is widely spread in the workplace. Therefore, it may be inappropriate to set one or two Article such as the Article 28 and 29 to protect in-house subcontract workers from injury and illness. It is believed that it needs fundamental redirection and new approach with new paradigm to impose occupational safety and health duty to prime contractors.

Cone penetrometer incorporated with dynamic cone penetration method for investigation of track substructures

  • Hong, Won-Taek;Byun, Yong-Hoon;Kim, Sang Yeob;Lee, Jong-Sub
    • Smart Structures and Systems
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    • v.18 no.2
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    • pp.197-216
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    • 2016
  • The increased speed of a train causes increased loads that act on the track substructures. To ensure the safety of the track substructures, proper maintenance and repair are necessary based on an accurate characterization of strength and stiffness. The objective of this study is to develop and apply a cone penetrometer incorporated with the dynamic cone penetration method (CPD) for investigating track substructures. The CPD consists of an outer rod for dynamic penetration in the ballast layer and an inner rod with load cells for static penetration in the subgrade. Additionally, an energy-monitoring module composed of strain gauges and an accelerometer is connected to the head of the outer rod to measure the dynamic responses during the dynamic penetration. Moreover, eight strain gauges are installed in the load cells for static penetration to measure the cone tip resistance and the friction resistance during static penetration. To investigate the applicability of the developed CPD, laboratory and field tests are performed. The results of the CPD tests, i.e., profiles of the corrected dynamic cone penetration index (CDI), profiles of the cone tip and friction resistances, and the friction ratio are obtained at high resolution. Moreover, the maximum shear modulus of the subgrade is estimated using the relationships between the static penetration resistances and the maximum shear modulus obtained from the laboratory tests. This study suggests that the CPD test may be a useful method for the characterization of track substructures.

Study on the Testing Method for Setting Time of Set Accelerating Agent Using Shotcrete by Gilmour Needles (길모어침에 의한 숏크리트용 급결제의 품질시험방법에 대한 고찰)

  • Kim, Chun Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.6
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    • pp.195-200
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    • 2011
  • KS F 2782 (for shotcrete accelerators) standard cross-section of tunnel construction or repair is a reinforcement used in the field of shotcrete accelerators as a criterion in assessing shotcrete performance. Thus, KS F 2782 by standard accelerator will determine the nature of the product of concrete accelerators that will be used to record variations in the product roles, through determination of the quality of the experimental method to identify only the quality of the many variables that exist. This evaluation standard has so far distinguished accelerator products in indoor experiments that do not meet quality standards but were mostly for an on-site accelerator mixed with the shotcrete after being quite satisfied with the level of quality in a certain number of products. This observation is derived from the results of an indoor experiment considered to verify whether the site is suitable for indoor experiments, and whether its actual location in the city is relevant to the accelerator quality, to find a way to test if it fits. This study centers on the material conditions of the shotcrete accelerator and a variety of experimental results, and used the Gilmore needle to compare the compressive strength and KS F 2782 specification of the accelerator as a means to ensure product quality conformity analysis and for further research experiments. In conclusion, a portion of KS F 2782 standard that fixes the problems that can be resolved from the ground up as a whole is not a review for the domestic reality. As an indoor experiment to ensure uniformity in the field when applied in a sufficient correlation, complement must be in place.

Damage Status of Turnout System with Wooden Sleeper of Concrete Track on Urban Transit (도시철도 콘크리트궤도 목침목 분기기의 손상현황)

  • Choi, Jung-Youl;Han, Kyung-Sung;Bong, Jae-Gun;Jang, Cheol-Ju;Chung, Jee-Seung
    • The Journal of the Convergence on Culture Technology
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    • v.5 no.4
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    • pp.379-385
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    • 2019
  • The purpose of this study is to investigate the damage status of wood sleepers on concrete track of urban transit at different locations and to analyze the causes of damages. In addition, the turnout maintenance history during the service period of about 24 years was analyzed in conjunction with the train passing tonnage and that was to compare the current repair history. The most frequent damage components were rail, tie plate, spike and wooden sleeper. And, the damage caused by the defect of the rail fastening system such as spike and tie plate according to the deformation of the wooden sleeper was analyzed as the main type of damage. As a result, the damage of track components of turnout system was on the increase because they are directly affected by the train passing tonnage. The supplementary points of the check sheet for current turnout maintenance were derived and the improvement proposal was suggested based on the research results.

Improvement of Outdoor Spaces for the Children's Safety in Public Rental Housing (어린이 안전을 위한 공공임대주택단지 외부공간 환경개선에 관한 연구)

  • Min, Young Hee;Ha, Mi-Kyoung;Byun, Gi-Dong
    • Journal of the Korean housing association
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    • v.26 no.4
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    • pp.95-104
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    • 2015
  • Public rental housing in Korea has been initially provided for residential stability of low-income household focusing on solving quantitative insufficiency since 1980s. In the process of early stage of designing and planning public rental housing, qualitative aspects of considering children were not primary concern. This study aims to analyze the priority of environmental improvement of outdoor spaces for children's safety in public rental housing. First, literature review was performed in the reference of local residential safety guidelines, Universal Design, and CPTED guidelines. In each guidelines, common safety planning factors for children were extracted within different types of outdoor spaces. Second, based on literature analysis, residents evaluated importance and satisfaction level by different safety types, outdoor space type, and environmental planning factors. In results, residents evaluated high importance and showed low satisfaction for crime and traffic safety. Through IPA, facilities and parking space was evaluated where improvement is needed for the first priority, and planning factors were mostly concerned with surveillance and safety management system. Result shows general concern of public rental housing residents, about weak facility management and security system, and about socially isolated environment which heightened the fear of crime safety. Overall, poor maintenance of the complex environment and decrepit facilities are constantly raising risk of safety accidents especially for children. Considering residents' concern, environmental improvement should be considered in perspective of not only physical repair, but also facility management and security system.