• Journal of Environmental Science International
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• v.28 no.2
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• pp.259-266
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• 2019

Two main sources of data, meteorological data and land surface characteristics, are essential to effectively run a distributed rainfall-runoff model. The specification and averaging of the land surface characteristics in a suitable way is crucial to obtaining accurate runoff output. Recent advances in remote sensing techniques are often being used to derive better representations of these land surface characteristics. Due to the mismatch in scale between digital land cover maps and numerical grid sizes, issues related to upscaling or downscaling occur regularly. A specific method is typically selected to average and represent the land surface characteristics. This paper examines the amount of flooding by applying the FLO-2D routing model, where vegetation heterogeneity is manipulated using the Manning's roughness coefficient. Three different upscaling methods, arithmetic, dominant, and aggregation, were tested. To investigate further, the rainfall-runoff model with FLO-2D was facilitated in Yongdam catchment and heavy rainfall events during wet season were selected. The results show aggregation method provides better results, in terms of the amount of peak flow and the relative time taken to achieve it. These rwsults suggest that the aggregation method, which is a reasonably realistic description of area-averaged vegetation nature and characteristics, is more likely to occur in reality.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04a
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• pp.519-521
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• 2000

본 논문에서는 클러스터 정의시 사용하게 되는 특성으로 노드간 패스 수에 기반한 K-edge 컴포넌트의 그래픽 정의 방법과 노드를 클러스터화 하는 집합화(Aggregation)방법을 제시하였다. 집단화된 하이퍼텍스트 분리를 통해 이전 결과를 개선할 수 있으며, 집단내의 노드간 관련성을 가시화하여 비교할 수 있다.

• Proceedings of the Korea Contents Association Conference
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• 2005.05a
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• pp.396-400
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• 2005

In this paper, we propose an efficient full mesh topology aggregation method in PNNI networks. The proposed scheme can search multi-links efficiently using the depth priority method based on hop count instead of searching the all links. To evaluate performance of the proposed scheme, we compare/analyze the current method with the proposed scheme with respect to call success rate, access time and crankback rate. The result is that the proposed scheme is better than the current scheme in performance.

• KIEE International Transactions on Power Engineering
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• v.2A no.4
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• pp.136-144
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• 2002

Load models are very important for improving the accuracy of stability analysis and load flow studies. Various loads are connected to a power bus and their characteristics of power consumption change with voltage and frequency. Thus, the effect of voltage/frequency changes must be considered in load modeling. In this work, artificial neural networks-ANNs- were used to construct the component load models for more accurate modeling. A typical residential load was selected and subjected to a test under variable voltage/frequency conditions. Acquired data were used to construct component models by ANNs. The aggregation process of separately determined load models is also presented in the paper. Furthermore, this paper proposes a method to transform a single load model constructed by the aggregation method into a mathematical load model that can be used in traditional power system analysis software.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3681-3685
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• 2012

We developed a simple and effective method for the SERS-based detection of protein-small molecule complexes and label-free proteins using avidin-induced silver aggregation. Upon excitation with light of the appropriate wavelength (633 and 532 nm), the aggregated silver nanoparticles generate a strong electric field that couples with the resonance of the molecules (atto610 and cytochrome c), increasing the characteristic signals of these molecules and resulting in sensitive detection. The detection limit of biotin with the proposed method is as low as 48 ng/mL. The most important aspect of this method is the induction of silver aggregation by a protein (avidin), which makes the silver more biocompatible. This technique is very useful for the detection of protein-small molecule complexes.

• Journal of KIISE
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• v.44 no.7
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• pp.703-709
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• 2017

Outsourcing databases is to offload storage and computationally intensive tasks to the third party server. Therefore, data owners can manage big data, and handle queries from clients, without building a costly infrastructure. However, because of the insecurity of network systems, the third-party server may be untrusted, thus the query results from the server may be tampered with. This problem has motivated significant research efforts on authenticating various queries such as range query, kNN query, function query, etc. Although aggregation queries play a key role in analyzing big data, authenticating aggregation queries has not been extensively studied, and the previous works are not efficient for data with high dimension or a large number of distinct values. In this paper, we propose the AMR-tree that is a data structure, applied to authenticate aggregation queries. We also propose an efficient proof construction method and a verification method with the AMR-tree. Furthermore, we validate the performance of the proposed algorithm by conducting various experiments through changing parameters such as the number of distinct values, the number of records, and the dimension of data.

• Journal of Korea Spatial Information System Society
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• v.9 no.3
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• pp.1-16
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• 2007

A spatial data warehouse is a system to support decision making using a spatial data cube. A spatial data cube is composed of a dimension table and a fact table. For decision support using this spatial data cube, the concept hierarchy of spatial dimension and the summarized information of spatial fact should be provided. In the previous researches, however, spatial summarized information is deficient. In this paper, the spatial aggregation for spatial summarized information in a spatial data warehouse is proposed. The proposed spatial aggregation is separated of both the numerical aggregation and the object aggregation. The numerical aggregation is the operation to return a numerical data as a result of spatial analysis and the object aggregation returns the result represented to object. We provide the extended struct of spatial data for spatial aggregation and so our proposed method is efficient.

• Journal of the Korean Chemical Society
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• v.13 no.3
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• pp.209-214
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• 1969

The experiment have been carried out for the determination of aggregation state of isopolytantalate anion in aqueous solution by using "Ultracentrifuge Method". The molecular weight of this anion at pH 10.7 could be determined as a heptatantalate anion $Ta_7O_{22}^{9-}$.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.2 s.40
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• pp.33-42
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• 2007

A physical-based aggregation method was suggested to estimate surface roughness, which adequately represents the spatial heterogeneity of vegetation factors, from land cover property obtained from the remote sensing data. For the sensitivity analysis of surface roughness, the peak flow, peak time, and total volume were simulated by the NWS-PC. Effects of surface roughness estimated by three different integration methods (predominant, arithmetic mean, and aggregation approach) on the conceptual rainfall-runoff model parameters was analyzed. In the preliminary sensitivity test to surface roughness, the peak time had 10% variation and total volume had 2% variation. The peak time increased with surface roughness. A physical-based aggregation method was better than the existing method in the Soyanggang Dam basin for the results of STDEV, RMSE, NSE, and PME, but difference between them were small. The parameters related on the total baseflow were changed significantly with change of the surface roughness.

• Journal of Internet Computing and Services
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• v.12 no.5
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• pp.11-19
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• 2011

In this paper, Service Boundary Line approximation method is proposed to improve the accuracy of aggregated link state information for source routing in transport networks that conduct hierarchical QoS routing. The proposed method is especially useful for aggregating links that have both delay and bandwidth as their QoS parameters. This method selects the main path weight in the network and transports the data to the external networks together with the aggregation information, reducing information distortion caused from the loss of some path weight during aggregation process. In this paper, the main path weight is defined as outlier. Service Boundary Line has 2k+5parameters. k is the number of outliers. The number of storage spaces of Service Boundary Line changes according to the number of outliers. Simulation results show that our approximation method requires a storage space that 1.5-2 times larger than those in other known techniques depending on outlier selection method, but its information accuracy of proposed method in the ratio between storage space and information accuracy is higher.