• Title/Summary/Keyword: Quality Maintenance

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Performance Evaluation Method of Tunnel Scanner for Lining Crack Detection (터널 균열 검출에 활용되는 터널스캐너의 성능검증 방법론)

  • Bae, Sung-Jae;Jung, Wook;Chamrith, Sereivatana;Kim, Chan-Jin;Kim, Young-Min;Hong, Sung-Ho;Kim, Jung-Gon;Kim, Jung-Yeol
    • Journal of the Society of Disaster Information
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    • v.17 no.1
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    • pp.39-52
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    • 2021
  • Purpose: Recently, due to increasing usage of high-tech equipment for facility inspection, the need of verifying high-tech equipment is being emphasized. Therefore, the purpose of this paper is to develop performance evaluation methodology of tunnel scanners that inspect tunnel facilities. Method: This paper describes literature reviews regarding the performance evaluation methodology of high-tech based equipment for facility inspection. Based on these investigations and expert advisory meetings, this paper suggests a performance evaluation methodology of tunnel scanner. Result: First evaluation indicator states minimum performance standards of tunnel scanners. Second evaluation indicator is related to tunnel scanner quality. Conclusion: The performance evaluation methodology can provide reliable equipment performance catalogues, helping users to make a proper selection of equipment. Also, developers of equipment can get authorized verification of performances, preventing poor maintenance of facilities.

Effect of lateral differential settlement of high-speed railway subgrade on dynamic response of vehicle-track coupling systems

  • Zhang, Keping;Zhang, Xiaohui;Zhou, Shunhua
    • Structural Engineering and Mechanics
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    • v.80 no.5
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    • pp.491-501
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    • 2021
  • A difference in subgrade settlement between two rails of a track manifests as lateral differential subgrade settlement. This settlement causes unsteadiness in the motion of trains passing through the corresponding area. To illustrate the effect of lateral differential subgrade settlement on the dynamic response of a vehicle-track coupling system, a three-dimensional vehicle-track-subgrade coupling model was formulated by combining the vehicle-track dynamics theory and the finite element method. The wheel/rail force, car body acceleration, and derailment factor are chosen as evaluation indices of the system dynamic response. The effects of the amplitude and wavelength of lateral differential subgrade settlement as well as the driving speed of the vehicle are analyzed. The study reveals the following: The dynamic responses of the vehicle-track system generally increase linearly with the driving speed when the train passes through a lateral subgrade settlement area. The wheel/rail force acting on a rail with a large settlement exceeds that on a rail with a small settlement. The dynamic responses of the vehicle-track system increase with the amplitude of the lateral differential subgrade settlement. For a 250-km/h train speed, the proposed maximum amplitude for a lateral differential settlement with a wavelength of 20 m is 10 mm. The dynamic responses of the vehicle-track system decrease with an increase in the wavelength of the lateral differential subgrade settlement. To achieve a good operation quality of a train at a 250-km/h driving speed, the wavelength of a lateral differential subgrade settlement with an amplitude of 20 mm should not be less than 15 m. Monitoring lateral differential settlements should be given more emphasis in routine high-speed railway maintenance and repairs.

Enhanced sewage effluent treatment with oxidation and adsorption technologies for micropollutant control: current status and implications (미량오염물질 관리를 위한 산화 및 흡착 기반 하수 방류수 강화처리 기술의 연구 동향 및 시사점)

  • Choi, Sangki;Lee, Woongbae;Kim, Young Mo;Hong, Seok Won;Son, Heejong;Lee, Yunho
    • Journal of Korean Society of Water and Wastewater
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    • v.36 no.2
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    • pp.59-79
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    • 2022
  • Conventional wastewater treatment plants (WWTPs) do not fully remove micropollutants. Enhanced treatment of sewage effluents is being considered or implemented in some countries to minimize the discharge of problematic micropollutants from WWTPs. Representative enhanced sewage treatment technologies for micropollutant removal were reviewed, including their current status of research and development. Advanced oxidation processes (AOPs) such as ozonation and UV/H2O2 and adsorption processes using powdered (PAC) and granular activated carbon (GAC) were mainly discussed with focusing on process principles for the micropollutant removal, effect of process operation and water matrix factors, and technical and economic feasibility. Pilot- and full-scale studies have shown that ozonation, PAC, and GAC can achieve significant elimination of various micropollutants at economically feasible costs(0.16-0.29 €/m3). Considering the current status of domestic WWTPs, ozonation and PAC were found to be the most feasible options for the enhanced sewage effluent treatment. Although ozonation and PAC are all mature technologies, a range of technical aspects should be considered for their successful application, such as energy consumption, CO2 emission, byproduct or waste generation, and ease of system construction/operation/maintenance. More feasibility studies considering domestic wastewater characteristics and WWTP conditions are required to apply ozonation or PAC/GAC adsorption process to enhance sewage effluent treatment in Korea.

A Study on the Reverse Engineering and Wear Analysis for Remanufacturing Planner Miller (플래너 밀러 재제조를 위한 역설계 및 마모 분석에 관한 연구)

  • Choi, Doo-Han;Kong, Seok-Hwan;Byeon, Jeong-Won;Kim, Tae-Woo;Hong, Dae-Sun
    • Journal of the Korean Society of Industry Convergence
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    • v.25 no.6_2
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    • pp.1103-1110
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    • 2022
  • The old machine tools that have been used for a long time cause both increase in defective rate and decrease in productivity compared to new machines due to wear and failure of their components. In order to improve productivity and quality of machined components through remanufacturing, it is necessary to analyze the wear and failure of major components of old machine tools. In this study, the process for reverse engineering is designed for the remanufacture of planner millers, which belong to a very large machine tool. Also, the suitability of the designed process is verified through the analysis of the selected remanufactured components. In the first step of the process, some major components of the aging planner miller are scanned using a 3D laser scanner. In the next step, reverse engineering is performed using the data obtained through 3D scanning. Finally, wear and failure analysis is performed by comparing the reverse engineering data with the scan data. As a result, this reverse design and wear analysis can complement the insufficient design database and reduce costs in the maintenance of remanufactured products.

A Scoping Review of Health-Related Intervention Studies Using Intervention Mapping in South Korea (중재 매핑을 활용한 국내 건강관련 중재연구의 주제범위 고찰)

  • Park, Jiyoung;Cho, Jeonghyun;Im, Mihae;Hwang, Gahui
    • Journal of Korean Public Health Nursing
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    • v.35 no.3
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    • pp.448-468
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    • 2021
  • Objectives: This study aimed to understand the trends and issues of health-related intervention research using Intervention Mapping over the last ten years in South Korea. Intervention Mapping is a representative planning protocol to develop theory-and-evidence-based health promotion programs. Methods: The scoping review method was undertaken, and a total of 20 studies were analyzed using Intervention Mapping six steps. Results: The Korean health-related intervention studies using Intervention Mapping showed low methodological quality. In step 1, only 7 out of 20 studies organized a planning group consisting of various stakeholders. In step 2, about half of the studies did not present a matrix, which is the core essential component of Intervention Mapping. In step 5, only 1 out of 20 studies presented program adopters and maintainers. In step 6, most studies described effect evaluation relatively, but only one study mentioned process evaluation. Conclusions: In order to develop sustainable and cost-effective programs, systematic planning using Intervention Mapping is required from the research planning stage. In addition, a concrete and realistic plan needs to be established for the development of programs and adoption, dissemination and maintenance of programs.

Development and Performance Improvement of old Aluminum Extruder Remanufacturing Technology (노후된 알루미늄 압출기의 재제조 기술 개발 및 성능 개선)

  • Sang-Min Yoon;Hang-Chul Jung;Man-Seek Kong
    • Journal of the Korean Society of Industry Convergence
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    • v.26 no.1
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    • pp.95-103
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    • 2023
  • The domestic remanufacturing industry is concentrated in auto parts, so it is necessary to expand into various industries. In the domestic aluminum industry, the extrusion process accounts for more than 40% of the total, but the old and management of the extrusion equipment is not done properly. In particular, the extruder has a structure in which equipment is not replaced until major parts are damaged or worn, so there are problems such as lower process precision, productivity and production efficiency compared to new equipment, and high maintenance costs. In this study, the old extruder was remanufactured for major high-risk parts through Failure Mode and Effect Analysis(FMEA), and the process level and performance of the extruder were evaluated before and after remanufacturing. Compared to the existing extruder, the standard deviation of the remanufacture extruder was reduced by 93.5%, 57.9%, and 70.0%, respectively, in major process control items such as container temperature, billet temperature, and ram speed, keeping performance constant. In addition, it was possible to produce products with complex shapes that could not be produced before due to problems such as dimensional deviation within tolerances. In this study, remanufacturing guidelines were presented by analyzing the effect of failure modes of the old extruder, and the performance improvement of the extruder was confirmed.

A Study on the Expanded Application of the Educational Facility Safety Certification Toward Libraries and Student Training Facilities (도서관과 학생수련시설에 대한 교육시설 안전인증 요소의 확대적용 방안 연구)

  • Seung-Hoon Han;Jae-Hyang Kim
    • Land and Housing Review
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    • v.14 no.3
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    • pp.107-123
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    • 2023
  • In order to create a safe and comfortable educational environment and improve the quality of education, the 'Act on the Safety and Maintenance of Educational Facilities' was enacted in 2021. Accordingly, 'Educational Facility Safety Certification Operation Regulations' was established. Safety certification targets are classified into 'kindergarten', 'elementary/middle/high school and special schools', and 'university and other educational facilities'. Other educational facilities include libraries and student training facilities. However, student training facilities and libraries are different from schools as facilities for special activities such as training and reading. Therefore, the unique characteristics of the facility must be reflected in the 'Educational Facility Safety Certification Operation Regulations'. This study analyzed how the 'Educational Facility Safety Certification Operation Regulation' reflects the special characteristics of student training facilities and libraries that are 'other educational facilities'. The previous certification system and guidelines were compared and analyzed, and the on-site survey method was used. Finally, it was confirmed that each of the library and the student training facility needed 9 detailed criteria reviews.

Assessment of Visitors' Satisfaction and Intention to Revisit of Bukcheon Iceland Poppy Festival in Hadong County, South Korea

  • Lee, Yeong Jin;Huh, Keun Young;Kim, Inhea;Bui, Hai Dang
    • Journal of People, Plants, and Environment
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    • v.22 no.6
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    • pp.629-639
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    • 2019
  • This study was conducted to analyze the characteristics of visitors to Hadong Bukcheon Iceland Poppy (BIP) Festival in order to sustain and enhance local flower festivals as a garden tourism. A questionnaire was distributed to BIP Festival visitors from May 18 to 27, 2018. A total of 167 responses were subject to be analyzed. Descriptive statistics analysis was mainly used and focused on describing the results in direct to explain the BIP Festival as a garden tourism. The number of female visitors and those in their 40s and 50s was high. Most of the visitors were found to live in other cities or counties near the area where BIP Festival was held and to prefer festivals held on the theme of nature and local features. The revisit rate and awareness of BIP Festival were 52.1% and 72.5% respectively. They mainly obtained the information on BIP Festival from people around them including family members, friends and colleagues, or from the Internet. Most answered that BIP festival was the most important destination on their trip. The major motives of BIP Festival visit included "spending quality time with family or friends (34.1%)", "appreciating Iceland poppy and gardens (25.6%)", and "enjoying oneself (tranquility, mental rest, etc.; 21.3%). As a companion, family and friends/colleagues accounted for 62.3% and 26.3% respectively. Most were found to spend 1-2 hours on visiting BIP festival and stay in Hadong county for a quarter of a day. In satisfaction of BIP Festival itself, "display and maintenance of Iceland poppy (3.76)" and "easiness of viewing (places arrangement, path, etc.) (3.57)" were high. In satisfaction of public relation and information, "service and hospitality of guides and desk clerks (3.66)" was high. The intention to revisit BIP Festival was nearly affirmative (3.73-3.80).

A Study on the Analysis of Nurses' Perception of the Fourth Industrial Revolution and the Importance and Performance of Future Core Nursing Competencies in a Tertiary Hospital (일 상급종합병원 간호사의 4차 산업혁명에 대한 인식 및 미래핵심간호역량 중요도-실행도 분석)

  • Kwon, Chi Hye;Kim, Mi Soon
    • Journal of Korean Clinical Nursing Research
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    • v.29 no.1
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    • pp.95-106
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    • 2023
  • Purpose: This study is descriptive survey research on the analysis of nurses' perception of the 4th industrial revolution and the importance and performance of future core nursing competencies in a tertiary hospital located in Seoul. Methods: Data were collected from 149 nurses with more than a year of work experience and analyzed using descriptive statistics, t-test, one-way ANOVA, and Importance Performance Analysis(IPA) with the IBM SPSS/WIN 25.0 program. Results: The nurses' perception of the 4th industrial revolution was 3.23±0.71 out of 5 points. The importance of future core nursing competencies was 4.31±0.48, and the performance of it was 3.47±0.54. The analysis results of IPA showed that A (area of continuous maintenance) included critical thinking, problem-solving skills, teamwork and collaboration, evidence-based practice, communication, quality improvement and safety, professionalism, self-regulation and self-management, and personal literacy. The specific competencies were not included in B (area of priority improvement). Creativity, informatics, healthcare policy, leadership, research ability, and continuing education were included in C (area of progressive improvement). Knowledge and patient-centered care, ability to manage resources as well as professional, legal, and ethical responsibility were included in D (area of overinvestment). Conclusion: The nurses seemed not to be fully prepared for the 4th industrial revolution. However, they were well aware of the importance of the future core nursing competencies. Therefore, if nurses increase the performance of core competencies in order of priority according to the IPA results, they will be able to independently lead the changing nursing field.

Analysis of genetic differentiation and population structure of the Korean-peninsula-endemic genus, Semisulcospira, using mitochondrial markers

  • Eun-Mi Kim;Yeon Jung Park;Hye Min Lee;Eun Soo Noh;Jung-Ha Kang;Bo-Hye Nam;Young-Ok Kim;Tae-Jin Choi
    • Fisheries and Aquatic Sciences
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    • v.25 no.12
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    • pp.601-618
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    • 2022
  • The genus Semisulcospira is an economically and ecologically valuable freshwater resource. Among the species, Semisulcospira coreana, Semisulcospira forticosta and Semisulcospira tegulata are endemic to the Korean peninsula and Semisulcospira gottschei is widespread in Asia. Therefore, maintenance and conservation of wild populations of these snails are important. We investigated the genetic diversity and population structure of Semisulcospira based on the mitochondrial cytochrome c oxidase subunit I (COI), NADH dehydrogenase subunit 4 (ND4), and combined mitochondrial DNA (COI + ND4) sequences. All four species and various genetic makers showed a high level of haplotype diversity and a low level of nucleotide diversity. In addition, Fu's Fs and Tajima's D neutrality tests were performed to assess the variation in size among populations. Neutrality tests of the four species yielded negative Fu's Fs and Tajima's D values, except for populations with one haplotype. The minimum spanning network indicated a common haplotype for populations of S. coreana, S. tegulata and S. gottschei, whereas S. forticosta had a rare haplotype. Also, genetic differences and gene flows between populations were assessed by analysis of molecular variance and using the pairwise fixation index. Our findings provided insight into the degree of preservation of the species' genetic diversity and could be utilized to enhance the management of endemic species.