• Journal of KIISE:Databases
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• v.36 no.1
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• pp.50-62
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• 2009

In wireless and mobile environments, data broadcasting is recognized as an effective way for data dissemination due to its benefits to bandwidth efficiency, energy-efficiency, and scalability. In this paper, we address the problem of delayed query processing raised by tree-based index structures in wireless broadcast environments, which increases the access time of the mobile clients. We propose a novel distributed index structure and a clustering strategy for streaming XML data which enable energy and latency-efficient broadcast of XML data. We first define the DIX node structure to implement a fully distributed index structure which contains tag name, attributes, and text content of an element as well as its corresponding indices. By exploiting the index information in the DIX node stream, a mobile client can access the wireless stream in a shorter latency. We also suggest a method of clustering DIX nodes in the stream, which can further enhance the performance of query processing over the stream in the mobile clients. Through extensive performance experiments, we demonstrate that our approach is effective for wireless broadcasting of XML data and outperforms the previous methods.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.640-643
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• 2004

기하급수적으로 증가하고 있는 방대한 양의 데이터를 효율적으로 저장하고, 검색하기 위한 방법으로 압축된 인덱스 자료구조(compressed index data structure)가 제안되었고 현재 활발히 연구되고 있다. 압축된 인덱스 자료구조란 데이터를 적절한 방법으로 색인화(indexing)하여 이를 압축(compression)된 자료구조로 저장하여, 데이터 검색의 성능저하 없이, 저장 공간을 줄일 수 있는 방법이다. 본 논문에서는 대표적인 방법으로 Ferragina와 Manzini가 제시한 FM-index를 다룬다. 이 방법을 구현하여 전체적인 성능에 영향을 미치는 요소들을 실험을 통해 분석하였다. 이를 통하여 각 파라미터들의 상관관계를 분석하고 이상적인 설정 값을 실험하였다.

• The Journal of Fisheries Business Administration
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• v.37 no.2 s.71
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• pp.85-109
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• 2006

This study is aimed to investigate the structure of world pollack markets and the position/competitiveness or Korea for WTO/NAMA Negotiation. First or all, it is clearly pointed out that many limitations and problems are inherent in FAO statistics that is widely utilized to investigate the structure of international seafood markets. Especially, it is impossible to find not only the data for Russia that is the top production and export country of pollack, but also the data for importing/exporting countries for pollack. In order to make up for these problems, the data for export and import of major countries are collected and analyzed. The results of analysis show the followings. First, it is clearly investigated that classification of fish products are different for countries. Second, it is understood the structure of international pollack market in actuality. The pollack market is segmented by frozen, fresh, dried, fillet, roe, surimi, etc. In addition, the pollack market has grown as much as 600,000 tons in amount and $1.2billion in value. Third, competitiveness of Korea in international pollack markets is measured quantitatively. It shows that Korea has low RAC index and TSI index, but high RMI index. Thus, it is identified that Korea becomes the largest pollack importing country. Fourth, the partial equilibrium analysis on pollack import market of Korea indicates that the frozen pollack has both price elasticity and substitution elasticity, while the fresh pollack has income elasticity.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.18 no.1
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• pp.89-99
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• 2010

The purpose of this study is analysis of Korean peninsula aircraft turbulence using the numerical weather prediction model, KWRF with the various turbulence index and pilot weather report data. Compared with the pilot weather report data and Calculated the turbulence index using the KWRF model result, many turbulence index show the similar horizontal distribution, except for the TUB2 and VWS. The analysis of vertical structure of turbulence, there are some difference each turbulence index respectively, but severe turbulence turn up in 15,000ft almost turbulence index. above 20,000ft height, intensity of turbulence vary each turbulence index. Through this turbulence study, It is founded on the research and development of the Korean peninsula aircraft turbulence

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.6
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• pp.547-555
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• 2015

The vegetation index is a crucial parameter in many biophysical studies of vegetation, and is also a valuable content in ecological processes researching. The OVIs (Optical Vegetation Index) that of using multispectral and hyperspectral data have been widely investigated in the literature, while the RVI (Radar Vegetation Index) that of considering volume scattering measurement has been paid relatively little attention. Also, there was only some efforts have been put to fuse the OVI with the RVI as an integrated vegetation index. To address this issue, this paper presents a novel FVI (Fusion Vegetation Index) that uses multispectral and full-PolSAR (Polarimetric Synthetic Aperture Radar) data. By fusing a NDVI (Normalized Difference Vegetation Index) of RapidEye and an RVI of C-band Radarsat-2, we demonstrated that the proposed FVI has higher separability in different vegetation types than only with OVI and RVI. Also, the experimental results show that the proposed index not only has information on the vegetation greenness of the NDVI, but also has information on the canopy structure of the RVI. Based on this preliminary result, since the vegetation monitoring is more detailed, it could be possible in various application fields; this synergistic FVI will be further developed in the future.

• Asia-Pacific Journal of Business
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• v.14 no.1
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• pp.439-451
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• 2023

Purpose - Market structure is crucial to identify as it defines the market states for new and existing container ports to perform within a given region. the study aims to compare the major ports in the Bay of Bengal in the context of Chittagong Port. Design/methodology/approach - For this study, the past 9 years of container volume data have been collected and analyzed through the HHI index, BCG matrix and shift effect analysis. Based on the analysis, this study has found that the Chittagong Port is in an oligopoly competitive market structure. Findings - The findings have shown that port in low market share and low growth in very recent years with the moderately concentrated ports HHI index. The shift effect analysis shows that the container volumes shifted from one port to another in the 2019 and 2020 periods. This study is the pioneer study in the Bay of Bengal region to identify the market structure, analyze market share and growth, and analyze the market concentration. Research implications or Originality - Future recommendations for the port authority is to take advantage of geolocation; attract international; tax exemption, faster clearance process, reduced waiting charges; increasing storage and technological machinery; promoting maritime logistics education; promoting Chittagong tourism; collaboration with other countries. Also, this study can be used as basic data for the establishment of a new supply chain between Korea and Southwest Asia for the Korean government and companies.

• Korean Journal of Computational Design and Engineering
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• v.14 no.1
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• pp.33-41
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• 2009

Triangular mesh models are widely used in reverse engineering, computer graphics, rapid prototyping and NC(numerical controller) tool-path generation. Triangular mesh models are generated from point clouds, surface models and solid models. A halfedge-based triangular mesh data structure is proposed and the development considerations are presented. In the presented data structure, halfedge is the key data structure. Halfedge stores its triangle index and the order in the triangle. Triangles do not store the halfedge lists explicitly. Halfedge is referred by value and defined when it is required. Proposed data structure supports four design requirements: efficient rendering, compact memory, supporting efficient algorithms and easy programming.

• The KIPS Transactions:PartD
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• v.13D no.3 s.106
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• pp.325-336
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• 2006

For supporting LBS service, recent studies on spatial network databases (SNDB) have been done actively. In order to gain good performance on query processing in SNDB, we, in this paper. design efficient storage and index structures for spatial network data, point of interests (POIs), and moving objects on spatial networks. First, we design a spatial network file organization for maintaining the spatial network data itself consisting of both node and edges. Secondly, we design a POI storage and index structure which is used for gaining fast accesses to POIs, like restaurant, hotel, and gas station. Thirdly, we design a signature-based storage and index structure for efficiently maintaining past, current, and expected future trajectory information of moving objects. Finally, we show that the storage and index structures designed in this paper outperform the existing storage structures for spatial networks as well as the conventional trajectory index structures for moving objects.

• Journal of KIISE:Databases
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• v.31 no.1
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• pp.13-22
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• 2004

With the proliferation of multimedia data, there is an increasing need to support the indexing and retrieval of high-dimensional image data. Although there have been many efforts, the performance of existing multidimensional indexing methods is not satisfactory in high dimensions. Thus the dimensionality reduction and the approximate solution methods were tried to deal with the so-called dimensionality curse. But these methods are inevitably accompanied by the loss of precision of query results. Therefore, recently, the vector approximation-based methods such as the VA- file and the LPC-file were developed to preserve the precision of query results. However, the performance of the vector approximation-based methods depend largely on the size of the approximation file and they lose the advantages of the multidimensional indexing methods that prune much search space. In this paper, we propose a new index structure called the GC-tree for efficient similarity search in image databases. The GC-tree is based on a special subspace partitioning strategy which is optimized for clustered high-dimensional images. It adaptively partitions the data space based on a density function and dynamically constructs an index structure. The resultant index structure adapts well to the strongly clustered distribution of high-dimensional images.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.944-958
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• 2011

Soil hydraulic properties such as hydraulic conductivity or water retention which are costly to measure can be indirectly generated by soil pedotransfer function (PTF) using easily obtainable soil data. The field soil structure description which is routinely recorded could also be used in PTF as an input to reduce the uncertainty. The purposes of this study were to use qualitative morphological soil structure descriptions and soil structural index into PTF and to evaluate their contribution in the prediction of soil hydraulic properties. We transformed categorical morphological descriptions of soil structure into quantitative values using categorical principal component analysis (CATPCA). This approach was tested with a large data set from the US National Pedon Characterization database with the aid of a categorical regression tree analysis. Six different PTFs were used to predict the saturated hydraulic conductivity and those results were averaged to quantify the uncertainty. Quantified morphological description was successively used in multiple linear regression approach to predict the averaged ensemble saturated conductivity. The selected stepwise regression model with only the transformed morphological variables and structural index as predictors predicted the $K_{sat}$ with $r^2$ = 0.48 (p = 0.018), indicating the feasibility of CATPCA approach. In a regression tree analysis, soil structure index and soil texture turned out to be important factors in the prediction of the hydraulic properties. Among structural descriptions size class turned out to be an important grouping parameter in the regression tree. Bulk density, clay content, W33 and structural index explained clusters selected by a two step clustering technique, implying the morphologically described soil structural features are closely related to soil physical as well as hydraulic properties. Although this study provided relatively new method which related soil structure description to soil structure index, the same approach should be tested using a datasets containing the actual measurement of hydraulic properties. More insight on the predictive power of soil structure index to estimate hydraulic properties would be achieved by considering measured the saturated hydraulic conductivity and the soil water retention.