The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform
Ryosuke Shibasaki - One of the best experts on this subject based on the ideXlab platform.
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handling spatio temporal uncertainties of geo objects for Dynamic Update of gis databases from multi source data commission iii icwg hilly
2017Co-Authors: Ryosuke ShibasakiAbstract:Institute of Industrial Science, The University of TokyoABSTRACT:As more GIS's are used in many institutions and fields, the importance of keeping GIS database current iskeenly recognized. To fulfill the requirement, a concept of Dynamic Update of GIS databases using a widevariety of data from multi-sources is proposed and a methodological framework is proposed to realize it. Atfirst, a model to represent geo-objects with spatio-temporal uncertainties is proposed. The model can serveas a basis to handle geo-objects with different levels of spatio-temporal uncertainties especially in integratingdata from multi-sources. Secondly, a method is proposed to estimate or reconstruct status of relatively static
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handling spatio temporal uncertainties of geo objects for Dynamic Update of gis databases from multisource data
Spatial Information from Digital Photogrammetry and Computer Vision: ISPRS Commission III Symposium, 1994Co-Authors: Ryosuke ShibasakiAbstract:As more GISs are used in many institutions and fields, the importance of keeping GIS database current is keenly recognized. To fulfill the requirement, a concept of Dynamic Update of GIS databases using a wide variety of data from multiple sources is proposed and a methodological framework is proposed to realize it. At first, a model to represent geo-objects with spatio- temporal uncertainties is proposed. The model can serve as a basis to handle geo-objects with different levels of spatio-temporal uncertainties especially in integrating data from multiple sources. Secondly, a method is proposed to estimate or reconstruct the status of relatively static geo-objects which only emerge and extinguish using observational data from multiple sources. Further extension of the method is required to estimate the status of more Dynamic geo-objects. To merge geometric data with different levels of uncertainties, a method to estimate the `most probable' position of a line feature with a statistically sound basis is proposed. It is necessary to validate the effectiveness of this methodological framework using actual data of an urban object such as houses or structures.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Zili Shao - One of the best experts on this subject based on the ideXlab platform.
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an efficient algorithm for Dynamic shortest path tree Update in network routing
Journal of Communications and Networks, 2007Co-Authors: Bin Xiao, Zili ShaoAbstract:Shortest path tree (SPT) construction is essential in high performance routing in an interior network using link state protocols. When some links have new state values, SPTs may be rebuilt, but the total rebuilding of the SPT in a static way for a large computer network is not only computationally expensive, unnecessary modifications can cause routing table instability. This paper presents a new Update algorithm, Dynamic shortest path tree (DSPT) that is computationally economical and that maintains the unmodified nodes mostly from an old SPT to a new SPT. The proposed algorithm reduces redundancy using a Dynamic Update approach where an edge becomes the significant edge when it is extracted from a built edge list Q. The average number of significant edges are identified through probability analysis based on an arbitrary tree structure. An Update derived from significant edges is more efficient because the DSPT algorithm neglect most other redundant edges that do not participate in the construction of a new SPT. Our complexity analysis and experimental results show that DSPT is faster than other known methods. It can also be extended to solve the SPT updating problem in a graph with negative weight edges.
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Dynamic shortest path tree Update for multiple link state decrements
Global Communications Conference, 2004Co-Authors: Bin Xiao, Qingfeng Zhuge, Zili ShaoAbstract:Previous approaches for the shortest path tree (SPT) Dynamic Update have mainly focused on the case of one link state change. Little work has been done on the problem of deriving a new SPT based on its old one for multiple link state decrements in a network that applies link-state routing protocols. The complexity of this problem comes from there being no accurate boundary of nodes to be Updated in an updating process and that multiple decrements can be accumulated. Two Dynamic algorithms (MaxR, MinD) are proposed to reduce the times for node updating. Compared with other algorithms for the SPT Update of multiple edge weight decrements, our algorithms yield fewer times for node Updates during the Dynamic Update process. Such an achievement is attained by the mechanism of part node updating in a branch on the SPT after a particular node selection from a built node list. Simulation results are given to show our improvements.
Liyong Wan - One of the best experts on this subject based on the ideXlab platform.
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a xml document coding schema based on binary
Applied Mechanics and Materials, 2014Co-Authors: Liyong WanAbstract:In order to resolve the inefficiency for XML data query and support Dynamic Updates, etc, this paper has proposed an improved method to encode XML document nodes. On the basic of region encoding and the prefix encoding, it introduces a XML document coding schema base on binary (CSBB). The CSBB code use binary encoding strategy and make the bit string inserted in order. The bit string inserted algorithm can generate ordered bit string to reserve space for the inserted new nodes, and not influence on the others. Experiments shows the CSBB code can effectively avoid re-encoding of nodes, and supports the nodes Dynamic Update.
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a xml document coding schema based on complete binary tree traversal
2013 International Conference on Advanced Information Engineering and Education Science (ICAIEES 2013), 2013Co-Authors: Ying Chen, Liyong Wan, Cheng LuoAbstract:In order to resolve the inefficiency for XML data query and support Dynamic Updates, etc. This paper has proposed a XML document coding schema based of binary tree traversal (BBCTT). Firstly, the XML document tree has been converted into the binary tree of XML document. Secondly, all nodes of the binary of XML document have been encoded with binary. According to characteristic of XML document tree and binary tree, query of XML document can be implemented. Experiment and analysis show that the coding not only has characteristic of a small storage space and relation determination of logic structure, but also can support Dynamic Update. Index Terms - XML, Update, query, code, Binary, Binary tree traversal.
Bin Xiao - One of the best experts on this subject based on the ideXlab platform.
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Dynamic spt Update for multiple link state decrements in network routing
The Journal of Supercomputing, 2008Co-Authors: Bin Xiao, Qin LuAbstract:Previous approaches to the Dynamic updating of Shortest Path Trees (SPTs) have in the main focused on just one link state change. Not much work has been done on the problem of deriving a new SPT from an existing SPT for multiple link state decrements in a network that applies link-state routing protocols such as OSPF and IS-IS. This problem is complex because in the process of updating an SPT there are, firstly, no simple forms of node set to presumable contain all nodes to be Updated and, secondly, multiple decrements can be accumulated to make the updating much harder. If we adopt the updating mechanisms engaged in one link state change for the case of multiple link state decrements, the result is node Update redundancy, as a node changes several times before it reaches its final state in the new SPT. This paper proposes two Dynamic algorithms (MaxR, MinD) for obviating unnecessary node Updates by having part nodes Updated in a branch on the SPT only after selecting a particular node from a built node list. The algorithm complexity analysis and simulation results show that MaxR and MinD require fewer node Updates during Dynamic Update procedures than do other algorithms for updating SPT of multiple link state decrements.
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an efficient algorithm for Dynamic shortest path tree Update in network routing
Journal of Communications and Networks, 2007Co-Authors: Bin Xiao, Zili ShaoAbstract:Shortest path tree (SPT) construction is essential in high performance routing in an interior network using link state protocols. When some links have new state values, SPTs may be rebuilt, but the total rebuilding of the SPT in a static way for a large computer network is not only computationally expensive, unnecessary modifications can cause routing table instability. This paper presents a new Update algorithm, Dynamic shortest path tree (DSPT) that is computationally economical and that maintains the unmodified nodes mostly from an old SPT to a new SPT. The proposed algorithm reduces redundancy using a Dynamic Update approach where an edge becomes the significant edge when it is extracted from a built edge list Q. The average number of significant edges are identified through probability analysis based on an arbitrary tree structure. An Update derived from significant edges is more efficient because the DSPT algorithm neglect most other redundant edges that do not participate in the construction of a new SPT. Our complexity analysis and experimental results show that DSPT is faster than other known methods. It can also be extended to solve the SPT updating problem in a graph with negative weight edges.
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Dynamic shortest path tree Update for multiple link state decrements
Global Communications Conference, 2004Co-Authors: Bin Xiao, Qingfeng Zhuge, Zili ShaoAbstract:Previous approaches for the shortest path tree (SPT) Dynamic Update have mainly focused on the case of one link state change. Little work has been done on the problem of deriving a new SPT based on its old one for multiple link state decrements in a network that applies link-state routing protocols. The complexity of this problem comes from there being no accurate boundary of nodes to be Updated in an updating process and that multiple decrements can be accumulated. Two Dynamic algorithms (MaxR, MinD) are proposed to reduce the times for node updating. Compared with other algorithms for the SPT Update of multiple edge weight decrements, our algorithms yield fewer times for node Updates during the Dynamic Update process. Such an achievement is attained by the mechanism of part node updating in a branch on the SPT after a particular node selection from a built node list. Simulation results are given to show our improvements.
Qian Wang - One of the best experts on this subject based on the ideXlab platform.
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a secure and Dynamic multi keyword ranked search scheme over encrypted cloud data
IEEE Transactions on Parallel and Distributed Systems, 2016Co-Authors: Zhihua Xia, Xinhui Wang, Xingming Sun, Qian WangAbstract:Due to the increasing popularity of cloud computing, more and more data owners are motivated to outsource their data to cloud servers for great convenience and reduced cost in data management. However, sensitive data should be encrypted before outsourcing for privacy requirements, which obsoletes data utilization like keyword-based document retrieval. In this paper, we present a secure multi-keyword ranked search scheme over encrypted cloud data, which simultaneously supports Dynamic Update operations like deletion and insertion of documents. Specifically, the vector space model and the widely-used TF $\;\times\;$ IDF model are combined in the index construction and query generation. We construct a special tree-based index structure and propose a “Greedy Depth-first Search” algorithm to provide efficient multi-keyword ranked search. The secure kNN algorithm is utilized to encrypt the index and query vectors, and meanwhile ensure accurate relevance score calculation between encrypted index and query vectors. In order to resist statistical attacks, phantom terms are added to the index vector for blinding search results. Due to the use of our special tree-based index structure, the proposed scheme can achieve sub-linear search time and deal with the deletion and insertion of documents flexibly. Extensive experiments are conducted to demonstrate the efficiency of the proposed scheme.
