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A dynamic replication management strategy in distributed gis

COMPUTERS & GEOSCIENCES 2018年 112卷 1-8页

作者： Pan, Shaoming Xiong, Lian Xu, Zhengquan Chong, Yanwen Meng, Qingxiang Wuhan Univ State Key Lab Informat Engn Surveying Mapping & R Wuhan Hubei Peoples R China Chongqing Univ Posts & Telecommun Sch Commun & Informat Engn Chongqing Peoples R China Wuhan Univ Sch Remote Sensing & Informat Engn Wuhan Hubei Peoples R China

Replication strategy is one of effective solutions to meet the requirement of service response time by preparing data in advance to avoid the delay of reading data from disks. This paper presents a brand-new method to create copies considering the selection of replicas set, the number of copies for each replica and the placement strategy of all copies. First, the popularities of all data are computed considering both the historical access records and the timeliness of the records. Then, replica set can be selected based on their recent popularities. Also, an enhanced Q-value scheme is proposed to assign the number of copies for each replica. Finally, a reasonable copies placement strategy is designed to meet the requirement of load balance. In addition, we present several experiments that compare the proposed method with techniques that use other replication management strategies. The results show that the proposed model has better performance than other algorithms in all respects. Moreover, the experiments based on different parameters also demonstrated the effectiveness and adaptability of the proposed algorithm.

关键词： Data replication Replication management Geospatial data Data popularity distributed gis

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An enhanced active caching strategy for data-intensive computations in distributed gis

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JOURNAL OF SUPERCOMPUTING 2017年第10期73卷 4324-4346页

作者： Pan, Shaoming Chong, Yanwen Xu, Zhengquan Tan, Xicheng Wuhan Univ State Key Lab Informat Engn Surveying Mapping & R Wuhan Hubei Peoples R China Wuhan Univ Int Sch Software Dept Spatial Informat & Digital Technol Wuhan Hubei Peoples R China Collaborat Innovat Ctr Geospatial Technol Wuhan Hubei Peoples R China

Caching can prepare data for computational tasks in advance by tracking the requirements and behaviors of distributed geographical information systems to reduce network latency and improve computational performance. This paper presents an enhanced method to actively cache data for data-intensive computations that considers both data relationships and the timeliness of those relationships. First, the access correlations, the correlation steps and the times of the correlations are computed based on the behaviors of the computational tasks. Because the influence of historically accessed records will decrease gradually over time, only recently accessed records are used. To track changes in the relationships and prevent cache waste problems, each record is given a different age-based weight. A conditional caching probability can then be computed based on the timeliness relationships, which can be used to find the appropriate data to compute simultaneously. Finally, we present several experiments that compare the proposed method with techniques that use other data placement strategies, active caching strategies and passive caching algorithms. The results show that the proposed model has better performance than other algorithms in all respects. In addition, the proposed model results in a lower cache replacement ratio. The experiments with different data sets on different data scales indicate that the proposed algorithm can also be used in large-scale distributed environments.

关键词： Active caching distributed computing Data correlation Spatial data distributed gis

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Schemes for Data and User Authentication in distributed gis

Schemes for Data and User Authentication in Distributed GIS

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4th International Workshop on Information Fusion and Geographical Information Systems

作者： Shtanko, Sergey Pankin, Andrey RAS St Petersburg Inst Informat & Automat St Petersburg 199178 Russia

ISBN: (纸本)9783642003035

The paper specifies approaches to the realization of data and User authentication functions in distributed gis, allowing for avoiding the existing protocols' disadvantages, and thus accounting for the requirements for the geographical information system (gis) safety. The authors propose the method Of user's private key storing at the server for the cases when the private key storing cannot be realized at the user's end. A method binding the user's identification process to the geographical location is proposed.

关键词： distributed gis Electronic digital signature Authentication

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A distributed gis for managing shanghai landscape resources

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Geographic Information Sciences 2005年第1期11卷 29-39页

作者： Zhu, Yue Yang, Chaowei Wong, David W. Kafatos, Menas Earth Systems and GeoInformation Sciences School of Computational Sciences George Mason University United States Shanghai CityGIS Developing Corp. Shanghai 75 Wanping Nan Road Xuhui District China

Given the decentralized computing environment for managing landscape resources in Shanghai, China, this paper introduces a distributed gis application to support a more efficient and effective approach for resource management. Four critical computing issues related to such a distributed gis are addressed: (1) large image management, (2) time dimension management, (3) network communication of geospatial information within the computer network, and (4) spatial data access through a spatial data engine. This paper suggests possible solutions to these four issues and illustrates how general landscape management functions are implemented through a distributed gis. This paper also offers some insights on the design and development of a distributed gis. © 2005 Taylor & Francis Group, LLC.

关键词： distributed gis Image library Landscape Time scaled spatial data model

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Model Sharing based on distributed gis A Case Study of Tapes-G Model

Model Sharing based on Distributed GIS A Case Study of Tapes...

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IEEE International Geoscience and Remote Sensing Symposium (IGARSS)

作者： Feng, Min Zhu, Yunqiang Chinese Acad Sci Grad Univ Dept Biol Beijing Peoples R China Chinese Acad Sci Inst Res Geog Sci & Nat Resource Beijing Peoples R China

ISBN: (纸本)9780780395091

distributed Model Sharing Service provides a platform for gis models to share their functions. The service is developed under the .Net environment and runs as Web Services. The interface of the service is designed, which conforms to the specifications of OGC, such as OWS and WPS. Therefore, service requestors will not be limited to any operation systems and software. As an example, the work of sharing Tapes-G, a topical hydrological model, is introduced.

关键词： distributed gis Computer Model Tapes-G Models Sharing

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Design and implementation of agent-based distributed gis

Design and implementation of agent-based distributed GIS

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2nd International Conference on Image and Graphics

作者： Luo, YW Wang, XL Xu, ZQ Peking Univ Dept Comp Sci & Technol Beijing 100871 Peoples R China

In this paper, agent technology is applied into distributed gis. A distributed gis oriented multi-agent system model is presented, whose architecture, working mechanism and implementation are discussed in detail. At l... 详细信息

ISBN: (纸本)0819446564

关键词： distributed gis agent DCOM multi-thread overlay analysis

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Extending distributed gis to support geo-collaborative crisis management

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Geographic Information Sciences 2005年第1期11卷 4-14页

作者： Cai, Guoray School of Information Sciences and Technology Pennsylvania State University University Park PA 16802 United States

Crises are often complex, geographical scale problems that require professionals to work in teams while dealing with a large amount of geographic information for decision making. However, current geospatial technologies do not directly support group entities working with geographic information–they impede rather than facilitate human-human collaborations and communication. Towards the goal of making gis “collaboration-friendly,” this paper explores the potentials of extending distributed gis with groupware and intelligent communication agents to support geo-collaborative crisis management by teams. Members of such a team are often geographically distributed and play different roles. In addition to the architectural choice, special attention was given to the computational approach to enable collaborative geographic information dialogues in spatial decision-making contexts. Collaboration requires representation and reasoning on a team mental model, which must be constructed from dialogue contexts and shared knowledge. An implementation of an intelligent, multimodal, multi-user geographic information environment, called GCCM_Connect, is presented as a proof-of-concept for the proposed architecture. © 2005 Taylor & Francis Group, LLC.

关键词： Crisis management distributed gis Geo-collaboration Groupware

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Building distributed Web gis: A Mobile Agent Based Approach

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Wuhan University Journal of Natural Sciences 2001年第Z1期6卷 474-481页

作者： jhguan@*** Guan Ji hong 1 , Zhou Shui geng 2 , Bian Fu ling 3, Meng Ling kui 3 1. School of Computer, Wuhan University, Wuhan 430072, China 2. State Key Laboratory of Software Engineering, Wuhan University, Wuhan 430072, Chin School of Computer Wuhan University Wuhan 430072 China

The diversity of giss and the wide spread availability of WWW have led to an increasing amount of research on integrating a variety of heterogeneous and autonomous giss in a cooperative environment to construct a new generation of gis characterizing in open architecture, distributed computation, interoperability, and extensibility. Our on going research project MADgis (Mobile Agent based distributed Geographic Information System) is reported, in which we propose the architecture of MADgis to meet the requirements of integrating distributed gis applications under Internet environment. We first describe the architecture of MADgis, and detailed discussions focusing on the structure of client site, server site and mobile agent in MADgis. Then we explore key techniques for MADgis implementation.

关键词： distributed gis mobile agent architecture mobility interoperability

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Online image classification and analysis using OGC web processing service

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EARTH SCIENCE INFORMATICS 2019年第3期12卷 307-317页

作者： Singh, Hariom Garg, R. D. Karnatak, Harish C. Indian Inst Technol Roorkee Dept Civil Engn Geomat Engn Grp Roorkee Uttar Pradesh India ISRO Indian Inst Remote Sensing Dehra Dun Uttar Pradesh India

The online geoprocessing and analysis using state-of-the-art technology are offering automated analytical tools to a large group of users. This paper describes an online geoprocessing and analysis framework, which allows an inexperienced user to perform unsupervised classification of remote sensing data. The parallel computing based geoprocessing and analysis framework adopted in this work has been implemented using Free and Open Source Software for Geospatial (FOSS4G). Web Processing Service (WPS) based geoprocessing framework facilitates the deployment of unsupervised classification algorithm on the web in a standardized way. However, it is dynamic in nature to deploy other geoprocessing algorithms. The developed system describes how to process remote sensing data (Sentinel-2, Landsat-8, etc.) for classification and sharing the interoperable results in a distributed environment. To validate the classification results, a prototype architecture based on participatory gis is developed for field data collection, accuracy assessment and online dissemination. The accuracy assessment (i.e., overall accuracy, Kappa coefficient) is performed to validate the derived classification results using collected field data.

关键词： distributed gis Parallel computing Unsupervised classification Web processing service Participatory gis

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An automated and optimized approach for online spatial biodiversity model: a case study of OGC web processing service

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GEOCARTO INTERNATIONAL 2019年第2期34卷 194-214页

作者： Singh, Hariom Karnatak, Harish C. Garg, R. D. Indian Inst Technol Roorkee Civil Engn Dept Geomat Engn Grp Roorkee Uttar Pradesh India ISRO Indian Inst Remote Sensing Dehra Dun India

An online spatial biodiversity model (SBM) for optimized and automated spatial modelling and analysis of geospatial data is proposed, which is based on web processing service (WPS) and web service orchestration (WSO) in parallel computing environment. The developed model integrates distributed geospatial data in geoscientific processing workflow to compute the algorithms of spatial landscape indices over the web using free and open source software. A case study for Uttarakhand state of India demonstrates the model outputs such as spatial biodiversity disturbance index (SBDI) and spatial biological richness index (SBRI). In order to optimize and automate, an interactive web interface is developed using participatory gis approaches for implementing fuzzy AHP. In addition, sensitivity analysis and geosimulation experiments are also performed under distributed gis environment. Results suggest that parallel algorithms in SBM execute faster than sequential algorithms and validation of SBRI with biological diversity shows significant correlation by indicating high R-2 values.

关键词： Web processing service parallel computing spatial biodiversity model distributed gis fuzzy AHP participatory gis

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