• Title/Summary/Keyword: Ground current

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Comparative Study of Metro Service in Korea Using Servicescape (서비스스케이프를 활용한 한국의 지하철 서비스 비교연구)

  • Jia-Xing Long;Sung-Pil Lee
    • Journal of Service Research and Studies
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    • v.12 no.2
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    • pp.48-64
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    • 2022
  • The metro played a role in improving and alleviating the problems of urban ground transportation, promoting rational development of the city and at the same time leading the development of metro-related industries. There is no doubt that it had a double effect of enormous economic and social benefits on the development of the country as a whole. The purpose of this study is to apply the concept of servicescape to the metro and establish the definition of the Metro Servicescape(MSS). To this end, the service space and service facilities of the metro were analyzed, and the existing domestic and foreign literature related to servicescape was studied. First, this study defined the concept of servicescape of metro. Second, 10 elements suitable for the metro service landscape were derived through domestic and foreign service landscape studies. Third, through field surveys and analysis of metros in five cities in Seoul, Busan, Daegu, Daejeon, and Gwangju, the ranking of the current status of the domestic metro servicescapes was 203 Seoul metro, 197 Busan metro, 192 Daegu metro, 178 Gwangju metro, There were 172 metro lines in Daejeon. Among them, the four elements of comfort, sociality, cleanliness, and safety are the same, and accordingly, it seems that each city metro is the same standard. However, the six elements of aesthetics, spatiality, convenience, entertainment, openness and information were found to be different for each city metro. It is expected that the results of this study can provide a reference value for future metro service landscape research.

A Study on the Changes in the Back Garden of Gyeongbokgung Palace during Cheongwadae Period through an Interview with Landscape Manager (조경 관리자 인터뷰를 통한 청와대 시기 경복궁 후원의 변화에 관한 연구)

  • Kim, Kyu-Yeon;Lee, Shi-Young;Choi, Jaehyuck;Choi, Jong-Hee
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.41 no.2
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    • pp.26-34
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    • 2023
  • This study conducted interviews with former and current managers of Cheongwadae landscape architecture to provide basic information necessary to preserve, manage, and utilize Gyeongbokgung Palace's back garden, and the main conclusions summarized are as follows. First, the topography changed a lot with the construction of the main building and the official residence under President Roh Tae-woo. The water system was connected to Gyeongbokgung Palace in the past, but is now disconnected. Second, in the case of planting, the most important principles were the president's security and protocol, and accordingly, trees were placed or managed. Trees were planted by introducing excellent trees in various regions, and wildflowers and ground cover plants were frequently replaced according to the season. Third, facilities and roads were arranged for the president's protocol, hobbies, and workers' rest, and fire-fighting facilities were installed to prevent disaster in the forest area of Baegaksan Mountain. Fourth, the biggest inflection point of Gyeongbokgung Palace's back garden during Cheongwadae period was the change in topography due to the new construction of the main building and official residence during President Roh Tae-woo, the removal of A and B barbed wire fences that separated space during President Roh Moo-hyun, and the extensive landscaping carried out for the G20 Summit under President Lee Myung-bak. The area of Gyeongbokgung Palace's back garden is expected to face another inflection point due to the opening of Cheongwadae on May 10, 2022, and the work of evaluating the historical, academic, and landscape values of Gyeongbokgung Palace's back garden should be carried out while preserving the status.

A Servicism Model on the New Human and Education System (서비스주의 인간 및 교육 연구)

  • Hyunsoo Kim
    • Journal of Service Research and Studies
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    • v.12 no.3
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    • pp.115-133
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    • 2022
  • This study was conducted to design a new human model and education system for the sustainable life of mankind. Human society is facing a crisis. This study presents a comprehensive plan as the final version of the servicism study. Since the problems of human society are all human problems, research was conducted focusing on the new human and education system. Modern society is markedly different from the existing society in terms of time, space, and humanity, and the leading role of individuals is increased due to the increase in literacy, which can lead to breakdown and ground breaking in an instant. As the value of growth and freedom is increasing, technological innovation is accelerating, and industries and enterprises are growing significantly, so new technologies and industries may put human society at great risk. This study comprehensively diagnosed these problems in the current human society. The problems related to human and education were presented in depth while analyzing and synthesizing the problems presented in the existing servicism studies. The necessary and sufficient conditions for a new system to solve the problems raised were derived. And a system that satisfies these conditions was derived and presented. The new system was named servicism human and education system as a system based on the service philosophy. The structure, operation model, and implementation plan of the new system were presented. The basic structure is a human view that recognizes both reason and irrationality, an education system in which intelligence education and virtue education are balanced, and an education system in which human effort and the values of unwieldy nature are respected. A new education system needs to be put into operation along with the improvement of modern ideology and the compensation system for efforts. Since this study presented a macroscopic direction, further studies are needed to further refine this study.

Fluid Injection Simulation Considering Distinct Element Behavior and Fluid Flow into the Ground (지반내 입자거동 및 흐름을 고려한 수압작용 모델링)

  • Jeon, Je-Sung;Kim, Ki-Young
    • Journal of the Korean Geotechnical Society
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    • v.24 no.2
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    • pp.67-75
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    • 2008
  • It is interesting to note that distinct element method has been used extensively to model the response of micro and discontinuous behavior in geomechanics. Impressive advances related to response of distinct particles have been conducted and there were difficulties in considering fluid effect simultaneously. Current distinct element methods are progressively developed to solve particle-fluid coupling focused on fluid flow through soil, rock or porous medium. In this research, numerical simulations of fluid injection into particulate materials were conducted to observe cavity initiation and propagation using distinct element method. After generation of initial particles and wall elements, confining stress was applied by servo-control method. The fluid scheme solves the continuity and Navior-Stokes equations numerically, then derives pressure and velocity vectors for fixed grid by considering the existence of particles within the fluid cell. Fluid was injected as 7-step into the assembly in the x-direction from the inlet located at the center of the left boundary under confining stress condition, $0.1MP{\alpha}\;and\;0.5MP{\alpha}$, respectively. For each simulation, movement of particles, flow rate, fluid velocity, pressure history, wall stress including cavity initiation and propagation by interaction of flulid-paricles were analyzed.

A Study on the Development of Harmonic Limit Device for Stabilizing Main Circuit Equipment of Train (열차운행 안정화를 위한 주회로 기기의 고조파 제한장치 개발에 관한 연구)

  • Kim, Sung Joon;Chae, Eun Kyung;Kang, Jeong Won
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.8 no.6
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    • pp.853-861
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    • 2018
  • This paper proposes the application of harmonic constraints to address the problems caused by abnormal voltage increases when electric railway vehicles are running. The AC line that supplies the train with power during operation is used to provide electricity of 25kV/60 Hz, but gradually the size and frequency of harmonics involved in the line are varied with the technological evolution of the railroad vehicle electrical equipment. An increase in heat losses due to the failure of the instrument transformer (PT), the main circuit device, which is a serious problem with the recent train safety operation, or to the main displacement voltage. When high frequency components are introduced through low frequency Transformers of the main circuit device, the high intensity of the components is caused by the high intensity of the core and the current flow of the parasitic core is increased, thus generating heat. To solve this problem, the recent adjustment of the sequence has applied artificial NOTCH OFF of the power converter. However, the method of receiving and controlling the OFF signal operates by interaction between the ground and the vehicle's devices, thus it is invalid in the event of failure, and an actual accident is occurring. Therefore, the harmonic currents were required to prevent possible flow of harmonics, and conducted a study to prevent accidental occurrence of train accidents and to verify feasibility of the device through the simulations of the train's experimental analysis and the simulations of the train for safe operation.

Effect of Wind Load on Pile Foundation Stability in Solar Power Facilities on Slopes (풍하중이 경사지 태양광 발전시설의 기초 안정성에 미치는 영향 분석)

  • Woo, Jong-Won;Yu, Jeong-Yeon;Song, Ki-Il
    • Journal of the Korean Geotechnical Society
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    • v.39 no.12
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    • pp.47-60
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    • 2023
  • At present, in South Korea, there is a growing concern regarding solar power facilities installed on slopes because they are prone to damage caused by natural disasters, such as heavy rainfall and typhoons. Each year, these solar power facilities experience soil erosion due to heavy rainfall and foundation damage or detachment caused by strong wind loads. Despite these challenges, the interaction between the ground and structures is not adequately considered. Current analyses primarily focus on the structural stability under external loads; the overall facility site's stability-excluding the solar structures-in relation to its surrounding slopes is neglected. Therefore, in this study, we use finite-difference method analysis to simulate the behavior of the foundation and piles to assess changes in lateral displacement and bending stress in piles, as well as the safety factor of sloped terrains, in response to various influencing factors, such as pile diameter, spacing between piles, pile-embedding depth, wind loads, and dry and wet conditions. The analysis results indicate that pile spacing and wind loads significantly influence lateral displacement and bending stress in piles, whereas pile-embedding depth strongly influences the safety factor of sloped terrains. Moreover, we found that under certain conditions, the design criteria in domestic standards may not be met.

Analysis of The Human Thermal Environment in Jeju's Public Parking Lots in Summer and Suggestion for Its Modification (제주시 공영 주차장 내 여름철 인간 열환경 분석 및 저감 방안 제안)

  • Choi, Yuri;Park, Sookuk
    • Journal of the Korean Institute of Landscape Architecture
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    • v.52 no.3
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    • pp.18-32
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    • 2024
  • This study aims to analyze the summer human thermal environment in Jeju City's outdoor parking lots by measuring microclimate data and comparing pavement and vegetation albedoes and elements through computer simulations. In measured cases, results due to albedo showed no significance, but there was a significant difference between sunny and shaded areas by trees. The sunny area had a PET (physiological equivalent temperature) in the 'very hot' level, while the shaded area exhibited a 2-step lower 'warm' level. UTCI (universal thermal climate index) also showed that the sunny area was in the 'very strong heat stress' level, whereas the shaded area was 1-step lower in the 'strong heat stress' level, confirming the role of trees in reducing incoming solar radiant energy. Simulation results, using the measured albedoes, closely resembled the measured results. Regarding vegetation, scenarios with a wide canopy, high leaf density, and narrow planting spacing were effective in mitigating the human thermal environment, and the differences due to tree height varied across scenarios. The scenario with the lowest PET value was H9W9L3D8 (tree height 9m, canopy width 9m, leaf area index 3.0, planting spacing 8m), indicating a 0.7-step decrease compared to the current landscaping scenario. Thus, it was confirmed that, among landscaping elements, trees have a significant impact on the summer human thermal environment compared to ground pavement.

A Study on the Calculation of Consolidation Constants using Moisture Content of Sedimentary Clay in Busan and Gyeongnam Regions (부산·경남지역 퇴적 점토의 함수비를 이용한 압밀정수 산정 연구)

  • Sung-Uk Kang;Dae-Hwan Kim;Tae-hyung Kim;Chin-Gyo Chung;In-Gon Joo
    • Journal of the Korean Geosynthetics Society
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    • v.23 no.1
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    • pp.39-47
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    • 2024
  • In this study, physical property tests and standard consolidation tests were conducted on the marine clay of Busan New Port and North Port, the middle and lower reaches of the Nakdong River including Gimhae and Yangsan, and Ulsan regions. The moisture content, a property unrelated to sample disturbance with small individual test errors, was used for regression analysis with the compression index, virgin compression index, consolidation coefficient, expansion index, and secondary compression index, among others. Subsequently, the correlation and accuracy were evaluated. Upon analyzing the correlation between the moisture content, void ratio, and liquid limit commonly used physical properties for calculating compression indexes, it was confirmed that the liquid limit had the lowest correlation. Through a linear regression analysis of the consolidation constants using the current moisture content in the natural state, a high correlation was demonstrated. Relationship equations were then presented to determine settlement and settlement time. This study suggests that moisture content can be utilized as an alternative for evaluating and calculating consolidation constants when examining ground settlement in sedimentary clays distributed in the Busan and Gyeongnam regions.

Field Perceptions on the Staffing Situation of Academic Libraries (대학도서관 인력 현황에 관한 현장 인식 조사)

  • Eun Youp Rha;Sangoh Na;Jongwook Lee
    • Journal of Korean Library and Information Science Society
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    • v.55 no.1
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    • pp.123-143
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    • 2024
  • In this study, we analyzed the trends in staffing changes in academic libraries over the past ten years and surveyed staff working there to assess their perceptions of staffing levels and the current criteria for staffing allocation in academic libraries. We utilized statistical data from academic libraries to analyze staffing changes from 2014 to 2023. The survey was conducted through an online questionnaire targeting library staff, and responses from 216 respondents from 4-year universities and junior colleges were analyzed. The analysis of staffing changes revealed a decrease in the average number of employees in large 4-year universities and junior colleges, with a decrease in regular positions and an increase in non-regular positions. Survey results suggest causes such as declining school-age population and admissions quotas, budget shortages in universities, and structural adjustments. The perception of staff from 4-year universities and junior colleges regarding the criteria for staffing allocation was mainly negative, suggesting improvements such as increasing and refining criteria numbers, specifying standards for full-time librarians, clarifying criteria for compliance, and enhancing enforcement of standards. The results of this study can enhance understanding of staffing situations in academic libraries and serve as fundamental data for improving staffing criteria in the future, based on an understanding of librarians' perceptions on the ground.

Towards Efficient Aquaculture Monitoring: Ground-Based Camera Implementation for Real-Time Fish Detection and Tracking with YOLOv7 and SORT (효율적인 양식 모니터링을 향하여: YOLOv7 및 SORT를 사용한 실시간 물고기 감지 및 추적을 위한 지상 기반 카메라 구현)

  • TaeKyoung Roh;Sang-Hyun Ha;KiHwan Kim;Young-Jin Kang;Seok Chan Jeong
    • The Journal of Bigdata
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    • v.8 no.2
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    • pp.73-82
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    • 2023
  • With 78% of current fisheries workers being elderly, there's a pressing need to address labor shortages. Consequently, active research on smart aquaculture technologies, centered on object detection and tracking algorithms, is underway. These technologies allow for fish size analysis and behavior pattern forecasting, facilitating the development of real-time monitoring and automated systems. Our study utilized video data from cameras outside aquaculture facilities and implemented fish detection and tracking algorithms. We aimed to tackle high maintenance costs due to underwater conditions and camera corrosion from ammonia and pH levels. We evaluated the performance of a real-time system using YOLOv7 for fish detection and the SORT algorithm for movement tracking. YOLOv7 results demonstrated a trade-off between Recall and Precision, minimizing false detections from lighting, water currents, and shadows. Effective tracking was ascertained through re-identification. This research holds promise for enhancing smart aquaculture's operational efficiency and improving fishery facility management.