• Title/Summary/Keyword: 건설기술정보

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Damage Conditions and Assessment for Cut Slope Structures due to Acid Rock Drainage (산성암반배수에 의한 절취사면 구조물의 피해 현황과 평가)

  • Lee Gyoo Ho;Kim Jae Gon;Park Sam-Gyu;Lee Jin-Soo;Chon Chul-Min;Kim Tack Hyun
    • Journal of the Korean Geotechnical Society
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    • v.21 no.5
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    • pp.83-92
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    • 2005
  • The aim of this study was to investigate damage conditions of cut slope structures due to acid rock drainage (ARB) and to assess the acid production potential of various rocks. Acid rock drainage is produced by the oxidation of sulfide minerals contained in coal mine zone and mineralization belt of Pyeongan supergroup and Ogcheon group, pyrite-bearing andesite, and Tertiary acid sulfate soils in Korea. Most of cut slopes producing ARB have been treated with shotcrete to reduce ARD. According to the field observations, ARD had an adverse effect on slope structures. The corrosion of shotcrete, anchors and rock bolts and the bad germination and growth diseases of covering plants due to ARD were observed in the field. The concentration of heavy metals and pH of ARD from cut slope exceeded the environmental standard, indicating a high potential of environmental pollution of surrounding soil, surface water and ground water by the ARD. According to acid base accounting (ABA) of the studied samples, hydrothermally altered volcanic rocks, tuffs, coaly shales, tailings of metallic mine had a relatively high potential of acid production but gneiss and granite had no or less acid production potential. It is expected that the number of cut slopes will increase hereafter considering the present construction trend. In order to reduce the adverse effect of ARD in construction sites, we need to secure the data base for potential ARD producing area and to develop the ARD reduction technologies suitable.

A Study on the Function Overlap and Irrational Hierarchy System of Logistics Complexes of Inland Base: Focusing on the Case of the Integrated Freight Terminal in the Yeongnam Area (내륙 거점 물류단지 기능중첩 및 연계체계 불합리성에 관한 연구: 영남권 복합물류 터미널을 사례로)

  • JUNG, Jin Uk;PARK, Woonho;JOH, Chang-Hyeon;PARK, Dongjoo
    • Journal of Korean Society of Transportation
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    • v.34 no.4
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    • pp.304-317
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    • 2016
  • The advancement in technology including transportation and information communication has accelerated the flow of supplies, and the importance of the national logistics policy has increased following the expansion of the regional range of logistics to a national range. The rapid growth of the domestic logistics market results in the deficit of logistics facilities, inefficient operation of logistics facilities, and a complicated distribution structure. It has precipitated a plan aimed at efficiency improvement by building base logistics facilities, but this market is now undergoing difficulties due to low performance. Many studies on the revitalization of base logistics facilities have been conducted, but a causal analysis focusing on the function overlap of private logistics businesses has been absent. Therefore, this study has analyzed the function overlap of logistics facilities and the irrationality of the system, which resulted from the lost function of Inland Freight bases in the Yeongnam region. By suggesting the cause of disuse of base logistics complexes from the function overlap in the ground transportation of domestic freight, the study can provide the policy implication for the national logistics infrastructure.

Application Examples of Daecheong Dam for Efficient Water Management Based on Integrated Water Management (통합물관리 기반 효율적 물관리를 위한 대청댐 실무적용 사례)

  • Kang, Kwon-Su;Heo, Jun-Haeng
    • Proceedings of the Korea Water Resources Association Conference
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    • 2017.05a
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    • pp.85-85
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    • 2017
  • 효율적 물관리란 거대한 물순환 과정에서 인간이 편안한 삶을 사는데 필요한 물의 이용효율을 극대화하는 것이다. 과거의 물관리는 이원화된 수량과 수질관리, 수량중심에서는 용수공급과 홍수조절이 주요한 관심사였다. 현재는 과거의 물관리에 친수와 환경을 더한 복잡한 분야로 확대되고 있다. 통합물관리란 물을 최적으로 관리하기 위해 물관리 이해당사자간의 소통과 물 기술의 고도화를 기반으로 기존에 분산된 물관리 구성요소들(시설 정보, 수량 수질 등)을 권역적으로 관리하는 것을 말한다. 본 연구에서는 대청댐 방류에 따른 금강 하류부의 홍수추적을 위해 수행한 댐하류 소유역별 강우량 빈도분석 과정, 용담댐 방류를 고려한 대청댐 홍수도달시간 검토, Poincare Section과 신경망기법을 이용한 수문자료 예측, 추계학적 다변량 해석과 다변량 신경망해석에 의한 대청댐 유입량 산정과정, 보조여수로 건설에 따른 주여수로와 보조여수로간의 연계운영방안, 단계(관심, 주의, 경계, 심각)를 고려한 대청댐 확보수위 산정, 저수지 중장기 운영계획 수립과 댐 운영 기준수위를 결정하기 위해 누가차분방식으로 적용되는 갈수기 유입량 빈도분석에 대한 실무적용 사례를 소개하고자 한다. 강우량 빈도분석 과정은 L-모멘트방법(Hosking과 Wallis, 1993)을 적용하였고, 홍수도달시간 검토는 평균유속, 하류 수위상승 기점 영향검토, 수리학적 모형(FLDWAV, Progressive lag method 등)을 활용하였다. 카오스 이론을 도입하여 대청댐 수문자료의 상관성 검토 및 추계학적 모형을 이용한 모의발생을 유도하여 수문자료 예측을 시행하였다. 추계학적 모형과 신경망모형 연구의 대상은 대청댐으로, 시계열 자료는 댐의 월강우량, 월유입량, 최고기온, 평균기온, 최소기온, 습도, 증발량 등의 자료를 기반으로 하였다. 적용기간은 1981~2009년의 자료를 이용하여 2010년 1월부터 12월까지 12개월 동안의 월유입량을 예측하였다. 수문자료 해석의 기본이 되는 약 30년간의 자료를 이용하여 분석을 실시하였다. 대청댐의 유입량 예측을 위해 적용된 모형으로는 추계학적 모형인 ARMA모형, TF모형, TFN 모형 등이 적용되었고, 또한 신경망 모형의 종류인 다층 퍼셉트론, PCA모형 등을 활용하여 실측치와 가장 가깝게 근사화시키는 방법론을 찾고자 하였다. 또한, 기존여수로와 보조여수로 연계운영을 위해 3차원 수치해석을 통한 댐하류 안정성 검토 및 확보수위 산정을 통해 단계(관심, 주의, 경계, 심각)별로 대처가 가능한 수위를 산정하였다.

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Influence of Internal and External Factors on the Inventory Turnover Change Rate (기업 내부적 및 외부적 요인이 재고자산회전율 변화율에 미치는 영향)

  • Seo, Yeong-Bok;Park, Chan-Kwon
    • Journal of Convergence for Information Technology
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    • v.11 no.9
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    • pp.94-108
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    • 2021
  • This study is to identify the internal and external factors of a company that can affect the rate of change in the inventory turnover ratio. In addition, by appropriately managing or responding to these factors, changes in the inventory turnover ratio do not occur abruptly, so that the company's business and financial performance can be improved. To confirm this, factors such as gross profit margin, cash flow volatility, advertising expenses, inflation, exchange rate rise, and leading economic index were selected, and these factors were predicted to affect the change rate of inventory turnover. Data of 85,878 companies were obtained from domestic securities listings, KOSDAQ listings, and externally audited companies, and multiple regression analysis was performed using the data. Gross profit margin and cash flow volatility have a significant positive (+) effect, advertising expenses have a negative (-) significant effect, and inflation and exchange rate rises have a negative (-) significant effect. As an influence, the leading economic index was tested to have a significant positive (+) effect. Through this, it is suggested that manufacturing companies can improve their business performance and achieve operational efficiency by well understanding and appropriately managing factors that can affect the change rate of inventory turnover.

Research on Digital twin-based Smart City model: Survey (디지털 트윈 기반 스마트 시티 모델 연구 동향 분석)

  • Han, Kun-Hee;Hong, Sunghyuck
    • Journal of Convergence for Information Technology
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    • v.11 no.11
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    • pp.172-177
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    • 2021
  • As part of the digital era, a digital twin that simulates the weak part of a product by performing a stress test that reduces the lifespan of some expensive equipment that cannot be done in reality by accurately moving the real world to virtual reality is being actively used in the manufacturing industry. Due to the development of IoT, the digital twin, which accurately collects data collected from the real world and makes it the same in the virtual space, is mutually beneficial through accurate prediction of urban life problems such as traffic, disaster, housing, quarantine, energy, environment, and aging. Based on its action, it is positioned as a necessary tool for smart city construction. Although digital twin is widely applied to the manufacturing field, this study proposes a smart city model suitable for the 4th industrial revolution era by using it to smart cities and increasing citizens' safety, welfare, and convenience through the proposed model. In addition, when a digital twin is applied to a smart city, it is expected that more accurate prediction and analysis will be possible by real-time synchronization between the real and virtual by maintaining realism and immediacy through real-time interaction.

The Effect of the Performance Compensation System on Organizational Effectiveness and Motivation and Corporate Performance : Focused on the Employees of Automobile Maintenance Service Companies (성과보상제도가 조직유효성 및 동기부여와 기업성과에 미치는 영향 : 자동차정비 서비스업체 종업원을 중심으로)

  • Hwang, Jung-Yup;Park, Chan-Kwon;Park, Sung-Min;Kim, Chae-Bogk
    • Journal of Convergence for Information Technology
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    • v.11 no.11
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    • pp.95-114
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    • 2021
  • This study is to study the effect of corporate performance compensation system on organizational effectiveness and motivation, and the effect of organizational effectiveness and motivation on corporate performance, targeting employees of automobile maintenance service companies. 430 questionnaires obtained through the survey were used for the study. As a result of testing the research hypothesis, tangible reward had a significant positive (+) effect on job satisfaction, but intangible reward had a positive (+) effect on job satisfaction, but it was not significant. Also, tangible and intangible rewards have a significant positive (+) effect on organizational commitment and motivation. Job satisfaction has a significant positive (+) effect on productivity and service quality. However, organizational commitment had a significant positive (+) effect on productivity, but had a positive (+) effect on service quality, but was not significant. Lastly, motivation has a significant positive (+) effect on productivity and service quality. Through the research results, the relationship structure between the performance compensation system, organizational effectiveness and motivation, and corporate performance was identified, and the application of the performance compensation system to employees in the automobile industry was presented.

Seismic Risk Assessment on Buried Electric Power Tunnels with the Use of Liquefaction Hazard Map in Metropolitan Areas (액상화 재해지도를 이용한 수도권 전력구 매설지반의 지진시 위험도 평가)

  • Baek, Woohyun;Choi, Jaesoon
    • Journal of Korean Society of Disaster and Security
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    • v.12 no.1
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    • pp.45-56
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    • 2019
  • In this study, the seismic risk has been evaluated by setting the bedrock acceleration to 0.154g which, was taking into consideration that the earthquake return period for the buried electric power tunnels in the metropolitan area to be 1,000 years. In this case, the risk assessment during the earthquake was carried out in three stages. In the first stage, the site classification was performed based on the site investigation data of the target area. Then, the LPI(Liquefaction Potential Index) was applied using the site amplification factor. After, candidates were selected using a hazard map. In the second stage, risk assessment analysis of seismic response are evaluated thoroughly after the recalculation of the LPI based on the site characteristics from the boring logs around the electric power area that are highly probable to be liquefied in the first stage. The third Stage visited the electric power tunnels that are highly probable of liquefaction in the second stage to compensate for the limitations based on the borehole data. At this time, the risk of liquefaction was finally evaluated based off of the reinforcement method used at the time of construction, the application of seismic design, and the condition of the site.

Simplified Bridge Weigh-In-Motion Algorithm using Strain Response of Short Span RC T-beam Bridge with no Crossbeam installed (가로보가 없는 단지간 RC T빔교의 변형률 응답을 이용한 단순화된 BWIM (Bridge Weigh-In-Motion) 알고리즘)

  • Jeon, Jun-Chang;Hwang, Yoon Koog;Lee, Hee-Hyun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.25 no.3
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    • pp.57-67
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    • 2021
  • A thorough administration of the arterial road network requires a continuous supply of updated and accurate information about the traffic that travels on the roads. One of the ways to effectively obtain the traffic volume and weight distribution of heavy vehicles is the BWIM technique, which is actively being studied. Unlike previous studies, this study was performed to develop a simplified Bridge Weigh-In-Motion (BWIM) algorithm that can easily estimate the axle spacing and weight of a traveling vehicle by utilizing the structural characteristics of the bridge. A short span RC T-beam bridge with no crossbeam installed was selected for the study, and then the strain response characteristics of bridge deck and girder was checked through preliminary field test. Based on the preliminary field test results, a simplified BWIM algorithm suitable for the bridge to be studied was derived. The validity and accuracy of the BWIM algorithm derived in this study were verified through field test. As a result of the verification test, the proposed BWIM algorithm can estimate the axle spacing and gross weight of the travelling vehicles with the average percent error of less than 3%.

Comparison of performance of automatic detection model of GPR signal considering the heterogeneous ground (지반의 불균질성을 고려한 GPR 신호의 자동탐지모델 성능 비교)

  • Lee, Sang Yun;Song, Ki-Il;Kang, Kyung Nam;Ryu, Hee Hwan
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.24 no.4
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    • pp.341-353
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    • 2022
  • Pipelines are buried in urban area, and the position (depth and orientation) of buried pipeline should be clearly identified before ground excavation. Although various geophysical methods can be used to detect the buried pipeline, it is not easy to identify the exact information of pipeline due to heterogeneous ground condition. Among various non-destructive geo-exploration methods, ground penetration radar (GPR) can explore the ground subsurface rapidly with relatively low cost compared to other exploration methods. However, the exploration data obtained from GPR requires considerable experiences because interpretation is not intuitive. Recently, researches on automated detection technology for GPR data using deep learning have been conducted. However, the lack of GPR data which is essential for training makes it difficult to build up the reliable detection model. To overcome this problem, we conducted a preliminary study to improve the performance of the detection model using finite difference time domain (FDTD)-based numerical analysis. Firstly, numerical analysis was performed with homogeneous soil media having single permittivity. In case of heterogeneous ground, numerical analysis was performed considering the ground heterogeneity using fractal technique. Secondly, deep learning was carried out using convolutional neural network. Detection Model-A is trained with data set obtained from homogeneous ground. And, detection Model-B is trained with data set obtained from homogeneous ground and heterogeneous ground. As a result, it is found that the detection Model-B which is trained including heterogeneous ground shows better performance than detection Model-A. It indicates the ground heterogeneity should be considered to increase the performance of automated detection model for GPR exploration.

3D Explosion Analyses of Hydrogen Refueling Station Structure Using Portable LiDAR Scanner and AUTODYN (휴대형 라이다 스캐너와 AUTODYN를 이용한 수소 충전소 구조물의 3차원 폭발해석)

  • Baluch, Khaqan;Shin, Chanhwi;Cho, Yongdon;Cho, Sangho
    • Explosives and Blasting
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    • v.40 no.3
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    • pp.19-32
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    • 2022
  • Hydrogen is a fuel having the highest energy compared with other common fuels. This means hydrogen is a clean energy source for the future. However, using hydrogen as a fuel has implication regarding carrier and storage issues, as hydrogen is highly inflammable and unstable gas susceptible to explosion. Explosions resulting from hydrogen-air mixtures have already been encountered and well documented in research experiments. However, there are still large gaps in this research field as the use of numerical tools and field experiments are required to fully understand the safety measures necessary to prevent hydrogen explosions. The purpose of this present study is to develop and simulate 3D numerical modelling of an existing hydrogen gas station in Jeonju by using handheld LiDAR and Ansys AUTODYN, as well as the processing of point cloud scans and use of cloud dataset to develop FEM 3D meshed model for the numerical simulation to predict peak-over pressures. The results show that the Lidar scanning technique combined with the ANSYS AUTODYN can help to determine the safety distance and as well as construct, simulate and predict the peak over-pressures for hydrogen refueling station explosions.