• Title/Summary/Keyword: large-scale assessment

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Large Scale Rainfall-runoff Analysis Using SWAT Model: Case Study: Mekong River Basin (SWAT 모형을 이용한 대유역 강우-유출해석: 메콩강 유역을 중심으로)

  • Lee, Dae Eop;Yu, Wan Sik;Lee, Gi Ha
    • Journal of The Korean Society of Agricultural Engineers
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    • v.60 no.1
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    • pp.47-57
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    • 2018
  • This study implemented the rainfall-runoff analysis of the Mekong River basin using the SWAT (Soil and Water Assessment Tool). The runoff analysis was simulated for 2000~2007, and 11 parameters were calibrated using the SUFI-2 (Sequential Uncertainty Fitting-version 2) algorithm of SWAT-CUP (Calibration and Uncertainty Program). As a result of analyzing optimal parameters and sensitivity analysis for 6 cases, the parameter ALPHA_BF was found to be the most sensitive. The reproducibility of the rainfall-runoff results decreased with increasing number of stations used for parameter calibration. The rainfall-runoff simulation results of Case 6 showed that the RMSE of Nong Khai and Kratie stations were 0.97 and 0.9, respectively, and the runoff patterns were relatively accurately simulated. The runoff patterns of Mukdahan and Khong Chaim stations were underestimated during the flood season from 2004 to 2005 but it was acceptable in terms of the overall runoff pattern. These results suggest that the combination of SWAT and SWAT-CUP models is applicable to very large watersheds such as the Mekong for rainfall-runoff simulation, but further studies are needed to reduce the range of modeling uncertainty.

A Study on The Evaluation of Fracture Strength for Large Sized Structures Based upon Their Fracturing Characteristics (대형구조물의 파괴강도 특성 평가기술에 관한 연구)

  • Moon-Sik Han
    • Journal of the Society of Naval Architects of Korea
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    • v.30 no.4
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    • pp.102-111
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    • 1993
  • One of the most important design procedures for large sized structures is the evaluation of fracture strength against fatigue and brittle fractures threatening to occur in their steel members. In this paper, the safety assessment based upon the knowledge about the fracturing characteristics of such ship structures was discussed, which can be estimated from such phenomena as fatigue crack propagation and brittle fractures, as obtained by employing fracture mechanics at the basic design stage. Model tests with a partial structure specimen of full size was carried out to authenticate a question as to whether or not the fracturing characteristics of such sophisticated structures could be estimated with precision from ordinary scale specimen tests, It was shown that the behviour of fatigue crack growth of large sized structures in this study could be predicted from the results of ordinary scale specimen test.

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Resampling for Roughness Coefficient of Surface Runoff Model Using Mosaic Scheme (모자이크기법을 이용한 지표유출모형의 조도계수 리샘플링)

  • Park, Sang-Sik;Kang, Boo-Sik
    • Journal of Environmental Science International
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    • v.20 no.1
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    • pp.93-106
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    • 2011
  • Physically-based resampling scheme for roughness coefficient of surface runoff considering the spatial landuse distribution was suggested for the purpose of effective operational application of recent grid-based distributed rainfall runoff model. Generally grid scale(mother scale) of hydrologic modeling can be greater than the scale (child scale) of original GIS thematic digital map when the objective basin is wide or topographically simple, so the modeler uses large grid scale. The resampled roughness coefficient was estimated and compared using 3 different schemes of Predominant, Composite and Mosaic approaches and total runoff volume and peak streamflow were computed through distributed rainfall-runoff model. For quantitative assessment of biases between computational simulation and observation, runoff responses for the roughness estimated using the 3 different schemes were evaluated using MAPE(Mean Areal Percentage Error), RMSE(Root-Mean Squared Error), and COE(Coefficient of Efficiency). As a result, in the case of 500m scale Mosaic resampling for the natural and urban basin, the distribution of surface runoff roughness coefficient shows biggest difference from that of original scale but surface runoff simulation shows smallest, especially in peakflow rather than total runoff volume.

Study on Application Plan of Forest Spatial Informaion Based on Unmanned Aerial Vehicle to Improve Environmental Impact Assessment (환경영향평가 개선을 위한 무인항공기 기반의 산림공간정보 활용 방안 연구)

  • Sung, Hyun-Chan;Zhu, Yong-Yan;Jeon, Seong-Woo
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.22 no.6
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    • pp.63-76
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    • 2019
  • UAVs are unmanned, autonomous or remotely piloted aircraft. As UAVs become smaller, lighter and more economical, their applications continue to expand. Researches on UAVs in the field of remote sensing show development methods and purposes similar to those on satellite images, and they are widely used in studies such as 3D image composition and monitoring. In the field of environmental impact assessment(EIA), satellite information and data are mainly used. However, only low-resolution images covering long distances and large-scale data allowing for rough examination are being provided, so their uses are seriously limited. Therefore, in this paper, we construct spatial information of forest area by using unmanned aerial vehicle and seek efficient utilization and policy improvement in the field of environmental impact assessment. As a result, high-resolution images and data from UAVs can be used to identify the location status of SEIA, EIA, and small scale EIA project plans and to evaluate detailed environmental impact analysis. In addition, when provided together with infographics about Post-environmental impact investigation, it was confirmed that the possibility of periodic spatial information construction and evaluation can be used throughout the entire project contents and project post-process.In order to provide sophisticated infographics for the EIA, drone photography and GCP surveying methods were derived.The results of this study will be used as a basis for improving high-resolution monitoring and environmental impact assessment in the forest sector.

Landscape Ecological Approaches to the Environmental Impact Assessment (환경영향평가기법의 경관생태학적 접근방안)

  • Choung, Heung-Lak;Hong, Sun-Kee;Lee, Hyun-Woo
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.8 no.3
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    • pp.73-85
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    • 2005
  • Natural disturbance and environmental pressure on natural ecosystems are gradually increasing, and the cause is significantly related to large-scale environmental pollution, global warming, decreasing biodiversity and habitat fragmentation. Environmental impact assessment(EIA) in Korea has been focused on distribution and composition of fauna and flora as major evaluation aspects in ecosystem assessment. It is well known that those characteristics of flora and fauna strongly depend on characteristics and quality of habitat and ecosystem. However, there is no items to assess habitat and ecosystems of spatial ecological system in EIA. Many countries are trying to develop the EIA items to consider the spatial characteristics of habitat and ecosystem and those ecological dynamics as well as species level. In this stream, landscape ecology is emerging discipline to examine spatial pattern and ecological process within/between habitats and ecosystems. Landscape ecological analysis, as a special tool for ecosystem evaluation, has been appropriately adopted to the EIA system in the advanced countries. This review paper tries to introducing the possibilities of landscape ecological concept into the Korean EIA system.

Seismic fragility assessment of isolated structures by using stochastic response database

  • Eem, Seung-Hyun;Jung, Hyung-Jo
    • Earthquakes and Structures
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    • v.14 no.5
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    • pp.389-398
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    • 2018
  • The seismic isolation system makes a structure isolated from ground motions to protect the structure from seismic events. Seismic isolation techniques have been implemented in full-scale buildings and bridges because of their simplicity, economic effectiveness, inherent stability and reliability. As for the responses of an isolated structure due to seismic events, it is well known that the most uncertain aspects are the seismic loading itself and structural properties. Due to the randomness of earthquakes and uncertainty of structures, seismic response distributions of an isolated structure are needed when evaluating the seismic fragility assessment (or probabilistic seismic safety assessment) of an isolated structure. Seismic response time histories are useful and often essential elements in its design or evaluation stage. Thus, a large number of non-linear dynamic analyses should be performed to evaluate the seismic performance of an isolated structure. However, it is a monumental task to gather the design or evaluation information of the isolated structure from too many seismic analyses, which is impractical. In this paper, a new methodology that can evaluate the seismic fragility assessment of an isolated structure is proposed by using stochastic response database, which is a device that can estimate the seismic response distributions of an isolated structure without any seismic response analyses. The seismic fragility assessment of the isolated nuclear power plant is performed using the proposed methodology. The proposed methodology is able to evaluate the seismic performance of isolated structures effectively and reduce the computational efforts tremendously.

Architectural model driven dependability analysis of computer based safety system in nuclear power plant

  • Wakankar, Amol;Kabra, Ashutosh;Bhattacharjee, A.K.;Karmakar, Gopinath
    • Nuclear Engineering and Technology
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    • v.51 no.2
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    • pp.463-478
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    • 2019
  • The most important non-functional requirements for dependability of any Embedded Real-Time Safety Systems are safety, availability and reliability requirements. System architecture plays the primary role in achieving these requirements. Compliance with these non-functional requirements should be ensured early in the development cycle with appropriate considerations during architectural design. In this paper, we present an application of system architecture modeling for quantitative assessment of system dependability. We use probabilistic model checker (PRISM), for dependability analysis of the DTMC model derived from system architecture model. In general, the model checking techniques do not scale well for analyzing large systems, because of prohibitively large state space. It limits the use of model checking techniques in analyzing the systems of practical interest. We propose abstraction based compositional analysis methodology to circumvent this limitation. The effectiveness of the proposed methodology has been demonstrated using the case study involving the dependability analysis of safety system of a large Pressurized Water Reactor (PWR).

Important Parameters Related With Fault for Site Investigation of HLW Geological Disposal

  • Jin, Kwangmin;Kihm, You Hong;Seo, Dong-Ik;Kim, Young-Seog
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.19 no.4
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    • pp.533-546
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    • 2021
  • Large earthquakes with (MW > ~ 6) result in ground shaking, surface ruptures, and permanent deformation with displacement. The earthquakes would damage important facilities and infrastructure such as large industrial establishments, nuclear power plants, and waste disposal sites. In particular, earthquake ruptures associated with large earthquakes can affect geological and engineered barriers such as deep geological repositories that are used for storing hazardous radioactive wastes. Earthquake-driven faults and surface ruptures exhibit various fault zone structural characteristics such as direction of earthquake propagation and rupture and asymmetric displacement patterns. Therefore, estimating the respect distances and hazardous areas has been challenging. We propose that considering multiple parameters, such as fault types, distribution, scale, activity, linkage patterns, damage zones, and respect distances, enable accurate identification of the sites for deep geological repositories and important facilities. This information would enable earthquake hazard assessment and lower earthquake-resulted hazards in potential earthquake-prone areas.

Arthroscopically Assisted Repair of Large to Massive Rotator Cuff Tears -The Role of Acromioplasty- (중범위 이상 회전근 개 파열 환자의 관절경적 봉합술 -견봉성형술의 역할-)

  • Lee, Kwang-Won;Kim, Kap-Jung;Lee, Hang-Ho;Kim, Byung-Sung;Kim, Ha-Yong;Choi, Won-Sik
    • Clinics in Shoulder and Elbow
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    • v.6 no.2
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    • pp.143-148
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    • 2003
  • Objectives: To analyze the postoperative functional outcome of shoulder in patients with arthroscopically assisted repair of large to massive rotator cuff tears with or without acromioplasty and role of acromioplasty. Materials and Methods: From June 1996 to June 2002, twenty six patients with large to massive rotator cuff tears were undergone arthroscopically assisted repair. Mean follow up was over one year. Fourteen were male and twelve were female. Mean age was 51 years old(39-66). Mean duration was 9 months. Acromioplasty was done in 14 cases concomitantly. They were divided into two groups. Group I: arthroscopic cuff repair with acromioplasty(14 cases). Group II: arthroscopic cuff repair without acromioplasty(12 cases). Each shoulder was evaluated at preoperative and final follow-up with Visual Analogue Scale(VAS), University of Pennsylvania Patient self-assessment of pain, University of Pennsylvania Patient self-assessment of function, ASES standardized shoulder assessment form, Simple Shoulder Test, UCLA score and range of motion(ROM). We analyzed the differences between the two groups. Shoulder ROM and acromioplasty were determining factors. Statistics was tested by correlation analysis and repeated measure ANOVA test. Results: At the final follow up, functional outcome and pain were improved but they had no statistical significance between the two groups(p>0.05). Combined procedure, acromioplasty, didn't affect on VAS. UCLA score, University of Pennsylvania Patient self-assessment of pain, University of Pennsylvania Patient self-assessment of function, ASf:S standardized shoulder assessment form and Simple Shoulder Test(p>0.05). In group II, forward flexion and abduction were statistically improved at the final follow up than in group I(p<0.05). Conclusions: It appears that arthroscopic repair is satisfactory procedure in patients with large to massive cuff tears. Combined procedure, acromioplasty, doesn't affect on postoperative functional outcome of shoulder.

The assessment of conservation value for agricultural pond wetland using the weighted function of modified RAM (modified RAM의 기능별 가중치 부여를 통한 농촌지역 연못형습지의 보전가치 평가)

  • Son, Jinkwan;Kim, Miheui;Lee, Siyoung;Kang, Donghyeon;Kang, Banghun
    • Journal of Korean Society of Rural Planning
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    • v.20 no.4
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    • pp.13-24
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    • 2014
  • The pond wetlands in agricultural landscape are important natural resources that carry out the function of bio-diversity conservation. However, recently, those have been gradually embedded as their utility value were disappeared. And, the assessment methods used for pond wetlands are insufficient. Therefore, this study was conducted to examine the conservation value of pond wetlands by using the modified RAM, and present the improvement of assesment methods. The study sites, a total of 32 pond of 4 types by land use, were selected on the basis of Ramsar Convention. Through the analysis of precedent studies, the weighted 8 functions were adjusted. According to the assessment results, pond wetlands made the largest contribution to Fishery and Herpetile Habitat function. In addition, it also made large contribution to Floral Diversity, Wildlife Habitat, and Water Quality Protection function. On the other hand, it made a small contribution to Aesthetics and Recreation, Runoff Attenuation, Shoreline /Stream Bank Protection, and Flood/Storm Water Storage function due to the characteristics of small-scale pond wetlands. In the assessment of 8 functions, house type showed the worst assessment result, and mountain type showed the best assessment result. It is thought that those are due to land use type in terms of vicinity. 10 items among 52 of the modified RAM showed the same assessment results in all land use types. Accordingly, it is required to be deleted and modified the assessment method. On the other hand, it is required to add age, interference, and water use to the assessment method. It is thought that these results can be utilized for the development and modification of assessment methods focused on pond wetlands in rural area.