• Title/Summary/Keyword: 공간 복잡도

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Distributed GIS-Based Watershed Rainfall-Runoff Model Development and Its Calibration using Weather Radar (기상레이더와 지형정보시스템을 이용한 분포형 강우-유출 유역모형의 개발과 검정)

  • Skahill, Brian E.;Choi, Woo-Hee;Kim, Min-Hwan;Kim, Sung-Kyun;Johnson, Lynn E.
    • Journal of Korea Water Resources Association
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    • v.36 no.2
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    • pp.285-300
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    • 2003
  • An event-based, kinematic, infiltration-excess, and distributed rainfall-runoff model using weather radar and Geographic Information System(GIS) was developed to acknowledge and account lot the spatial variability and uncertainty of several parameters relevant to storm surface runoff and surface flow The developed model is compatible with raster GIS and spatially and temporally varied rainfall data. To calibrate the model, Monte Carlo simulation and a likelihood measure are utilized; allowing for a range of possible system responses from the calibrated model. Using rain gauge adjusted radar-rainfall estimates, the developed model was applied and evaluated to a limited number of historical events for the Ralston Creek and Goldsmith Gulch basins within the Denver Urban Drainage and Flood Control District (UDFCD) that contain mixed land use classifications. While based on a limited number of Monte Carlo simulations and considered flood events, Nash and Sutcliffe efficiency score ranges of -0.19∼0.95 / -0.75∼0.81 were obtained from the calibrated models for the Ralston Creek and Goldsmith Gulch basins, based on a comparison of observed and simulated hydrographs. For the Ralston Creek and Goldsmith Gulch basins, Nash and Sutcliffe efficiency scores of 0.88/0.10, 0.14/0.71, and 0.99/0.95 for runoff volume, peak discharge, and time to peak, respectively, were obtained from the model.

Estimation of soil moisture based on sentinel-1 SAR data: focusing on cropland and grassland area (Sentienl-1 SAR 토양수분 산정 연구: 농지와 초지지역을 중심으로)

  • Cho, Seongkeun;Jeong, Jaehwan;Lee, Seulchan;Choi, Minha
    • Journal of Korea Water Resources Association
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    • v.53 no.11
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    • pp.973-983
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    • 2020
  • Recently, SAR (Synthetic Aperture Radar) is being highlighted as a solution to the coarse spatial resolution of remote sensing data in water resources research field. Spatial resolution up to 10 m of SAR backscattering coefficient has facilitated more elaborate analyses of the spatial distribution of soil moisture, compared to existing satellite-based coarse resolution (>10 km) soil moisture data. It is essential, however, to multilaterally analyze how various hydrological and environmental factors affect the backscattering coefficient, to utilize the data. In this study, soil moisture estimated by WCM (Water Cloud Model) and linear regression is compared with in-situ soil moisture data at 5 soil moisture observatories in the Korean peninsula. WCM shows suitable estimates for observing instant changes in soil moisture. However, it needs to be adjusted in terms of errors. Soil moisture estimated from linear regression shows a stable error range, but it cannot capture instant changes. The result also shows that the effect of soil moisture on backscattering coefficients differs greatly by land cover, distribution of vegetation, and water content of vegetation, hence that there're still limitations to apply preexisting models directly. Therefore, it is crucial to analyze variable effects from different environments and establish suitable soil moisture model, to apply SAR to water resources fields in Korea.

BIM Based Time-series Cost Model for Building Projects: Focusing on Construction Material Prices (BIM 기반의 설계단계 원가예측 시계열모델 -자재가격을 중심으로-)

  • Hwang, Sung-Joo;Park, Moon-Seo;Lee, Hyun-Soo;Kim, Hyun-Soo
    • Korean Journal of Construction Engineering and Management
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    • v.12 no.2
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    • pp.111-120
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    • 2011
  • High-rise buildings have recently increased over the residential, commercial and office facilities, thus an understanding of construction cost for high-rise building projects has been a fundamental issue due to enormous construction cost as well as unpredictable market conditions and fluctuations in the rate of inflation by long-term construction periods of high-rise projects. Especially, recent violent fluctuations of construction material prices add to problems in construction cost forecasting. This research, therefore, develops a time-series model with the Box-Jenkins methodologies and material prices time-series data in Korea in order to forecast future trends of unit prices of required materials. BIM (Building Information Modeling) approaches are also used to analyze injection time of construction resources and to conduct quantity takeoff so that total material price can be forecasted. Comparative analysis of Predictability of tentative ARIMA (Autoregressive Integrated Moving Average) models was conducted to determine optimal time-series model for forecasting future price trends. Proposed BIM based time series forecasting model can help to deal with sudden changes in economic conditions by estimating future material prices.

A binary adaptive arithmetic coding algorithm based on adaptive symbol changes for lossless medical image compression (무손실 의료 영상 압축을 위한 적응적 심볼 교환에 기반을 둔 이진 적응 산술 부호화 방법)

  • 지창우;박성한
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.12
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    • pp.2714-2726
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    • 1997
  • In this paper, adaptive symbol changes-based medical image compression method is presented. First, the differenctial image domain is obtained using the differentiation rules or obaptive predictors applied to original mdeical image. Also, the algorithm determines the context associated with the differential image from the domain. Then prediction symbols which are thought tobe the most probable differential image values are maintained at a high value through the adaptive symbol changes procedure based on estimates of the symbols with polarity coincidence between the differential image values to be coded under to context and differential image values in the model template. At the coding step, the differential image values are encoded as "predicted" or "non-predicted" by the binary adaptive arithmetic encoder, where a binary decision tree is employed. The simlation results indicate that the prediction hit ratios of differential image values using the proposed algorithm improve the coding gain by 25% and 23% than arithmetic coder with ISO JPEG lossless predictor and arithmetic coder with differentiation rules or adaptive predictors, respectively. It can be used in compression part of medical PACS because the proposed method allows the encoder be directly applied to the full bit-planes medical image without a decomposition of the full bit-plane into a series of binary bit-planes as well as lower complexity of encoder through using an additions when sub-dividing recursively unit intervals.

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A Three-Dimensional Galerkin-FEM Model with Density Variation (밀도 변화를 포함하는 3차원 연직함수 전개모형)

  • 이호진;정경태;소재귀;강관수;정종율
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.8 no.2
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    • pp.123-136
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    • 1996
  • A three-dimensional Galerkin-FEM model which can handle the temporal and spatial variation of density is presented. The hydrostatic approximation is used and density effects are included by means of conservation equation of heat and the equation of state. The finite difference grids are used in the horizontal plane and a set of linear-shape functions is used for the vertical expansion. The similarity transform is introduced to solve resultant matrix equations. The proposed model was first applied to the density-driven circulation in an idealized basin in the presence of the heat exchange between the air and the sea. The advection terms in the momentum equation were ignored, while the convection terms were retained in the heat equation. Coefficients of the vertical eddy viscosity and diffusivity were fixed to be constant. Calculation in a non-rotating idealized basin shows that the difference in heat capacity with depth gives rise to the horizontal gradient of temperature. Consequently, there is a steady new in the upper layer in the direction of increasing depth with compensatory counter flow .in the lower layer. With Coriolis force, geostrophic flow was predominant due to the balance between the pressure gradient and the Coriolis force. As a test in region of irregular topography, the model is applied to the Yellow Sea. Although the resultant flow was very complex, the character of the flow Showed to be geostrophic on the whole.

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Case study of design and construction for cutter change in EPB TBM tunneling (EPB 쉴드 TBM 커터 교체 설계 및 시공 사례 분석)

  • Lee, Jae-won;Kang, Sung-wook;Jung, Jae-hoon;Kang, Han-byul;Shin, Young Jin
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.24 no.6
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    • pp.553-581
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    • 2022
  • Shortly after tunnel boring machine (TBM) was introduced in the tunneling industry, the use of TBM has surprisingly increased worldwide due to its performance together with the benefit of being safely and environmentally friendly. One of the main cost items in the TBM tunneling in rock and soil is changing damaged or worn cutters. It is because that the cutter change is a time-consuming and costly activity that can significantly reduce the TBM utilization and advance rate and has a major effect on the total time and cost of TBM tunneling projects. Therefore, the importance of accurately evaluating the cutter life can never be overemphasized. However, the prediction of cutter wear in soil, rock including mixed face is very complex and not yet fully clarified, subsequently keeping engineers busy around the world. Various prediction models for cutter wear have been developed and introduced, but these models almost usually produce highly variable results due to inherent uncertainties in the models. In this study, a case study of design and construction of disc cutter change is introduced and analyzed, rather than proposing a prediction model of cutter wear. As the disc cutter is strongly affected by the geological condition, TBM machine characteristic and operation, authors believe it is very hard to suggest a generalized prediction model given the uncertainties and limitations therefore it would be more practical to analyze a real case and provide a detailed discussion of the difference between prediction and result for the cutter change. By doing so, up-to-date idea about planning and execution of cutter change in practice can be promoted.

Case of assembly process review and improvement for mega-diameter slurry shield TBM through the launching area (발진부지를 이용한 초대구경 이수식 쉴드TBM 조립공정 검토 및 개선 사례)

  • Park, Jinsoo;Jun, Samsu
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.24 no.6
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    • pp.637-658
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    • 2022
  • TBM tunnel is simple with the iterative process of excavating the ground, building a segment ring-build, and backfilling. Drill & Blast, a conventional tunnel construction method, is more complicated than the TBM tunnel and has some restrictions because it repeats the inspection, drilling, charging, blasting, ventilation, muck treatment, and installation of support materials. However, the preparation work for excavation requires time and cost based on a very detailed plan compared to Drill & Blasting, which reinforces the ground and forms a tunnel after the formation of tunnel portal. This is because the TBM equipment for excavating the target ground determines the success or failure of the construction. If the TBM, an expensive order-made equipment, is incorrectly configured at the assembly stage, it becomes difficult to excavate from the initial stage as well as the main excavation stage. When the assembled shield TBM equipment is dismantled again, and a situation of re-assembly occurs, it is difficult throughout the construction period due to economic loss as well as time. Therefore, in this study, the layout and plan of the site and the assembly process for each major part of the TBM equipment were reviewed for the assembly of slurry shield TBM to construct the largest diameter road tunnel in domestic passing through the Han River and minimized interference with other processes and the efficiency of cutter head assembly and transport were analyzed and improved to suit the site conditions.

Modified HOG Feature Extraction for Pedestrian Tracking (동영상에서 보행자 추적을 위한 변형된 HOG 특징 추출에 관한 연구)

  • Kim, Hoi-Jun;Park, Young-Soo;Kim, Ki-Bong;Lee, Sang-Hun
    • Journal of the Korea Convergence Society
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    • v.10 no.3
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    • pp.39-47
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    • 2019
  • In this paper, we proposed extracting modified Histogram of Oriented Gradients (HOG) features using background removal when tracking pedestrians in real time. HOG feature extraction has a problem of slow processing speed due to large computation amount. Background removal has been studied to improve computation reductions and tracking rate. Area removal was carried out using S and V channels in HSV color space to reduce feature extraction in unnecessary areas. The average S and V channels of the video were removed and the input video was totally dark, so that the object tracking may fail. Histogram equalization was performed to prevent this case. HOG features extracted from the removed region are reduced, and processing speed and tracking rates were improved by extracting clear HOG features. In this experiment, we experimented with videos with a large number of pedestrians or one pedestrian, complicated videos with backgrounds, and videos with severe tremors. Compared with the existing HOG-SVM method, the proposed method improved the processing speed by 41.84% and the error rate was reduced by 52.29%.

A Study on the Design of Data Model for Route Information based on S-100 (S-100 기반의 항로정보 데이터 모델 설계에 관한 연구)

  • PARK, Byung-Moon;KIM, Jae-Myeong;CHOI, Yun-Soo;OH, Se-Woong;JUNG, Min
    • Journal of the Korean Association of Geographic Information Studies
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    • v.22 no.2
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    • pp.50-64
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    • 2019
  • According to the Maritime Safety Act, there are all 34 routes including 5 traffic safety zones, 3 traffic separation schemes, 26 routes designated by regional maritime affairs departments in the Republic of Korea. In the SOLAS convention, the route information should be is effectively used for the safe navigation. However, the route information is complicatedly composed of the location of the route, the navigation rule by each route, the restriction of the navigation, and the anchorages. Moreover, the present method of providing information using the navigational chart and other publications is not effective for users to grasp the navigational information. Therefore, it was conducted to study the design of the S-100 based routing information data model developed by the International Hydrographic Organization to find ways to more effectively provide route information. To do this, the analysis of route requirement, selection of items, encoding test and users' review were carried out. Through expert user review, it was evaluated that the study on the design of the route information data model can be utilized as a good basic data for the route information integration service. Future research on the development of route information data models is expected to provide integrated route information services.

The Research of Layout Optimization for LNG Liquefaction Plant to Save the Capital Expenditures (LNG 액화 플랜트 배치 최적화를 통한 투자비 절감에 관한 연구)

  • Yang, Jin Seok;Lee, Chang Jun
    • Korean Chemical Engineering Research
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    • v.57 no.1
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    • pp.51-57
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    • 2019
  • A plant layout problem has a large impact on the overall construction cost of a plant. When determining a plant layout, various constraints associating with safety, environment, sufficient maintenance area, passages for workers, etc have to be considered together. In general plant layout problems, the main goal is to minimize the length of piping connecting equipments as satisfying various constraints. Since the process may suffer from the heat and friction loss, the piping length between equipments should be shorter. This problem can be represented by the mathematical formulation and the optimal solutions can be investigated by an optimization solver. General researches have overlooked many constraints such as maintenance spaces and safety distances between equipments. And, previous researches have tested benchmark processes. What the lack of general researches is that there is no realistic comparison. In this study, the plant layout of a real industrial C3MR (Propane precooling Mixed Refrigerant) process is studied. A MILP (Mixed Integer Linear Programming) including various constraints is developed. To avoid the violation of constraints, penalty functions are introduced. However, conventional optimization solvers handling the derivatives of an objective functions can not solve this problem due to the complexities of equations. Therefore, the PSO (Particle Swarm Optimization), which investigate an optimal solutions without differential equations, is selected to solve this problem. The results show that a proposed method contributes to saving the capital expenditures.