• Title/Summary/Keyword: Spatial assessment

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Validation of Assessment for Mean Flow Field Using Spatial Averaging of Instantaneous ADCP Velocity Measurements (ADCP 자료의 공간평균을 이용한 평균유속장 산정에 대한 검증)

  • Kim, Dong-Su;Kang, Boo-Sik
    • Journal of Environmental Science International
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    • v.20 no.1
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    • pp.107-118
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    • 2011
  • While the assessment of mean flow field is very important to characterize the hydrodynamic aspect of the flow regime in river, the conventional methodologies have required very time-consuming efforts and cost to obtain the mean flow field. The paper provides an efficient technique to quickly assess mean flow field by developing and applying spatial averaging method utilizing repeatedly surveyed acoustic Doppler current profiler(ADCP)'s cross-sectional measurements. ADCP has been widely used in measuring the detailed velocity and discharge in the last two decades. In order to validate the proposed spatial averaging method, the averaged velocity filed using the spatial averaging was compared with the bench-mark data computed by the time-averaging of the consistent fix-point ADCP measurement, which has been known as a valid but a bit inefficient way to obtain mean velocity field. The comparison showed a good agreement between two methods, which indicates that the spatial averaging method is able to be used as a surrogate way to assess the mean flow field. Bed shear stress distribution, which is a derived hydrodynamic quantity from the mean velocity field, was additionally computed by using both spatial and time-averaging methods, and they were compared each other so as to validate the spatial averaging method. This comparison also gave a good agreement. Therefore, such comparisons proved the validity of the spatial averaging to quickly assess mean flow field. The mean velocity field and its derived riverine quantities can be actively used for characterizing the flow dynamics as well as potentially applicable for validating numerical simulations.

Application of Spatial Autocorrelation for Analysis of Spatial Distribution Characteristics of Birds Observed in Namdaecheon River, Muju-gun, Jeollabuk-do, Korea (무주 남대천에 서식하는 조류의 공간적 분포특성 분석을 위한 공간자기상관 적용 연구)

  • Kang, Jong-Hyun;Kim, Yong-Ki;Yeon, Myung-Hun
    • Journal of Environmental Impact Assessment
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    • v.22 no.5
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    • pp.467-479
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    • 2013
  • This study was conducted to find out characterization of spatial distribution of birds observed in river areas. Our bird survey was carried out 4 times at 31 sites from January to September in 2011. A total of 1,609 accumulated individuals belonging to 59 species, 28 families and 11 orders were observed. In the result of spatial autocorrelation analysis using the richness index of the maximum counts of each sites, we confirmed that the distribution of birds in Namdaecheon river was clustered and the tendency of spatial autocorrelation was apparent. The area of each sites within a 200m radius was classified in four biotope categories such as agricultural land, forest, residential area and water area, and the spatial autocorrelation was analysed about four types. In the result of spatial autocorrelation analysis for four biotope categories, all types were showed the positive spatial autocorrelation, but the type of water area was higher than other types. The positive correlation was found between the water area and water birds in statistical significance. However, the forest birds had non-significance values. Therefore, it is appropriate to focus on water birds except for forest birds, when researches of bird distribution in river ecosystem is conducted. The number of bird species and individuals increased as the riverside of water area was to widen. Thus, if the areas of riverside offering the feeding and roosting area increase, it will be accommodated many birds. Also, the areas of riverside should be maintained naturally because it is an important habitats of birds. Our study area is on the outskirts the city of higher rates of forest and agricultural land, it may be unreasonable to apply our results to the whole rivers. If the research about the river flowing around the city will be conducted, it is expected to be useful to the relation study area such as ecological river's restoration.

Spatio-temporal Sensor Data Processing Techniques

  • Kim, Jeong-Joon
    • Journal of Information Processing Systems
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    • v.13 no.5
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    • pp.1259-1276
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    • 2017
  • As technologies related to sensor network are currently emerging and the use of GeoSensor is increasing along with the development of Internet of Things (IoT) technology, spatial query processing systems to efficiently process spatial sensor data are being actively studied. However, existing spatial query processing systems do not support a spatial-temporal data type and a spatial-temporal operator for processing spatialtemporal sensor data. Therefore, they are inadequate for processing spatial-temporal sensor data like GeoSensor. Accordingly, this paper developed a spatial-temporal query processing system, for efficient spatial-temporal query processing of spatial-temporal sensor data in a sensor network. Lastly, this paper verified the utility of System through a scenario, and proved that this system's performance is better than existing systems through performance assessment of performance time and memory usage.

The Consistency Assessment of Topological Relationships For a Collapse Operator in Multi-Scale Spatial Databases (다중축척 공간 데이터베이스의 축소연산자를 위한 위상관계 일관성 평가)

  • Kang Hae-Kyong;Li Ki-Joune
    • The KIPS Transactions:PartD
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    • v.12D no.6 s.102
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    • pp.837-848
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    • 2005
  • A multi-scale database is a set of spatial database, covering same geographic area with different scales and it can be derived from pre-existing databases. In the derivation processes of a new multi-scale spatial database, the geometries and topological relations on the source database can be transformed and the transformation can be the cause of the lack of integrity Therefore, it is necessary to assess the transformation whether it is consistent or not after the derivation process of a new multi-scale database. Thus, we propose assessment methods for the topological consistency between a source database and a derived multi-scale database in this paper. In particular, we focus on the case that 2-dimensional objects are collapsed to 1-dimensional ones in the derivation process of a multi-scale database. We also describe implementation of the assessment methods and show the results of the implementation with experimental data.

Comparative Evaluation among Different Kriging Techniques applied to GOSAT CO2 Map for North East Asia (GOSAT 기반의 동북아시아 CO2 분포도에 적용된 크리깅 기법의 비교평가)

  • Choi, Jin Ho;Um, Jung-Sup
    • Journal of Environmental Impact Assessment
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    • v.20 no.6
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    • pp.879-890
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    • 2011
  • The GOSAT (Greenhouse gases Observing SATellite) data provide new opportunities the most regionally complete and up-to-date assessment of $CO_2$. However, in practice, GOSAT records often suffer from missing data values mainly due to unfavorable meteorological condition in specific time periods of data acquisition. The aim of this research was to identify optimal spatial interpolation techniques to ensure the continuity of $CO_2$ from samples taken in the North East Asia. The accuracy among ordinary kriging (OK), universal kriging (UK) and simple kriging (SK) was compared based on the combined consideration of $R^2$ values, Root Mean Square Error (RMSE), Mean Error (ME) for variogram models. Cross validation for 1312 random sampling points indicate that the (UK) kriging is the best geostatistical method for spatial predictions of $CO_2$ in the East Asia region. The results from this study can be useful for selecting optimal kriging algorithm to produce $CO_2$ map of various landscapes. Also, data users may benefit from a statistical approach that would allow them to better understand the uncertainty and limitations of the GOSAT sample data.

Component fragility assessment of a long, curved multi-frame bridge: Uniform excitation versus spatially correlated ground motions

  • Jeon, Jong-Su;Shafieezadeh, Abdollah;DesRoches, Reginald
    • Structural Engineering and Mechanics
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    • v.65 no.5
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    • pp.633-644
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    • 2018
  • This paper presents the results of an assessment of the seismic fragility of a long, curved multi-frame bridge under multi-support earthquake excitations. To achieve this aim, the numerical model of columns retrofitted with elliptical steel jackets was developed and validated using existing experimental results. A detailed nonlinear numerical model of the bridge that can capture the inelastic response of various components was then created. Using nonlinear time-history analyses for a set of stochastically generated spatially variable ground motions, component demands were derived and then convolved with new capacity-based limit state models to obtain seismic fragility curves. The comparison of failure probabilities obtained from uniform and multi-support excitation analyses revealed that the consideration of spatial variability significantly reduced the median value of fragility curves for most components except for the abutments. This observation indicates that the assumption of uniform motions may considerably underestimate seismic demands. Moreover, the spatial correlation of ground motions resulted in reduced dispersion of demand models that consequently decreased the dispersion of fragility curves for all components. Therefore, the spatial variability of ground motions needs to be considered for reliable assessment of the seismic performance of long multi-frame bridge structures.

Evaluation of Economic Potential and Level of Concentration of the Regions of Kazakhstan

  • Nurlanova, Nailya K.;Kireyeva, Anel A.;Ruzanov, Rashid M.
    • The Journal of Asian Finance, Economics and Business
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    • v.4 no.2
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    • pp.37-44
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    • 2017
  • This research is devoted to the development of methods general and standard methodological approaches and approbation those for the evaluation of economic potential and level of concentration of the regions of Kazakhstan. This paper presents the results of development of the authors on the selection and justification of the methodological approaches for quantitative evaluation of the economic potential (the degree of territorial differentiation of the profile) and concentration of regions. In this study, we used scientific methods: method of analysis the main trends of economic development, and method of evaluation of concentration of the region. Based on the analysis of foreign techniques developed and tested methodical approaches to the assessment of the economic potential (index and coefficient methods). Proposed methodological approaches to the assessment profile of the territory and developed a system of indicators, which includes an aggregated index of spatial concentration, which accurately reflects the concentration of production in the region. This study shows the results of the analysis of the potential regional disparities and trends of economic development of Kazakhstan. By using, the proposed methodology shows the possibility of their use; we calculated the indicators of integrated assessment of the economic potential and indicators of spatial concentration.

Ecological Resource Assessment for Spatial Decision Support on Private land Policy inside National Parks, Korea (국립공원 사유지 정책의 공간의사결정지원을 위한 생태자원성 평가)

  • Lee, Gwan-Gyu
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.9 no.5
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    • pp.41-49
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    • 2006
  • Private land within national parks has raised acute questions for impact assessment practitioners as to whether it is ecologically resourceful enough to be conserved or whether it should be removed from national parks and compensated accordingly. The purpose of this study is to provide a framework for spatial decision support through assessing ecological resource of private land within national parks. In order to assess the ecological resource, private land within national parks was analyzed and quantified based upon topography, flora and fauna. National parks, according to the ecological resource assessment, have been divided into three groups : the parks in need of careful attention for conservation; the parks needed to be retained as buffers, and; the parks that can be released to private land. According to the analysis, part of Mountain Joowang is the third-tier land that does not require conservation efforts. This case study intends to help policy-makers decide whether some private land within national parks can be released and, after the release, what should be done to prevent reckless development of the released land.

Information System for Multi-scale Urban Landscape using Internet Image Map (인터넷 영상지도를 활용한 축척별 도시경관 정보시스템)

  • Um, Jung-Sup;Choi, Ja-Hyun
    • Journal of Environmental Impact Assessment
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    • v.11 no.4
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    • pp.289-309
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    • 2002
  • Solutions of many landscape problems depend on area-wide assessment and interpretation of spatial and physical characteristics over the study area. The authors argue that the public awareness for an area-wide urban landscape appears to be very low due to limited chance to the information. Acknowledging these constraints, an operational, user-friendly information system has been developed by combining internet technology with GIS. In particular, integration among satellite data and digital maps takes advantage of each component, and enables the landscape structure to be visualized, interacted with and deployed all on the Web. The 1m resolution IKONOS data realistically identified the major type of landscape by large scale spatial precision while TM data revealed successfully the major parameters that influence an area-wide spatial structure in the study area. This system would play a crucial role in improving the public awareness for area-wide landscape information if it is operationally introduced into the Government since the highly user-friendly interface based on image maps provides a completely new means for disseminating information for area-wide landscape in a visual and interactive manner to the general public.

Evaluation of Suitable Locations of Green Care Farm Complex According to Spatial Scale (공간규모별 치유농업단지 입지잠재력 평가)

  • Lim, Hye-Ji;Bae, Seung-Jong;Koo, Hee-Dong;Kim, Dae-Sik
    • Journal of Korean Society of Rural Planning
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    • v.27 no.3
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    • pp.93-102
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    • 2021
  • This study was attempted to provide a scientific basis for the problem of location selection by spatial scale for efficient promotion of projects related to green care farm complex. Location potential assessment system in local government scale consists of two major components from demand-side and supply-side consideration. The demand-side aspect considered the characteristics of potential users, while supply-side aspect used total 18 indices over 8 divisions under 3 fields. For the location potential assessment in district scale, total 8 indices under 3 major divisions were considered based on biological, physical, social, and economic environment. The application results of the location potential evaluation system in local government scale(excluding metropolitan cities) showed high location potential in southern Gyeonggi Province and near Busan Metropolitan City. As a result of applying the district-scale location potential evaluation system to Geumsan-gun, Geumsan-eup, Chubu-myeon, and Jewon-myeon have high potential. Further studies to improve the applicability of the developed indices are recommended by enhancing assessment indices, complementing base data, and reinforcing with spatial analysis.