Chunyang Hu

Collaborative Visualization of Large Scale Datasets Using Web Services

Visualization and collaboration of large scale data sets on Internet is still one of biggest challenges in scientific visualization. A distributed, real-time, collaborative system for large scale data like seismic model can be a valuable tool to support scientific research. In this paper, we present a new approach for Web-based synchronized collaborative visualization of large scale data using Web services and rich Web clients which supports collaborative visualization in Web browsers. We use WS-resources in WSRF (Web services resource framework) to maintain states collaborative server. On client side, we design an Ajax-based (asynchronous JavaScript and XML) application using standard Web technologies. A collaborative demonstration of 3D seismic model which is 2GB size is presented and experimental results are showed finally.

A hierarchical organization approach of multi-dimensional remote sensing data for lightweight Web Map Services

With the rapid development of the World Wide Web, remote sensing (RS) data have become available to a wider range of public/professional users than ever before. Web Map Services (WMSs) provide a simple Web interface for requesting RS data from distributed geospatial databases. RS data providers typically expect to provide lightweight WMSs. They have a low construction cost, and can be easily managed and deployed on standard hardware/software platforms. However, existing systems for WMSs are often heavyweight and inherently hard to manage, due to their improper usage of databases or data storage. That is, they are not suitable for public data services on the Web. In addition, RS data are moving toward the multi-dimensional paradigm, which is characterized by multi-sensor, multi-spectral, multi-temporal and high resolution. Therefore, an efficient organization and storage approach of multi-dimensional RS data is needed for lightweight WMSs, and the efficient WMSs must support multi-dimensional Web browsing. In this paper, we propose a Global Remote Sensing Data Hierarchical Model (GRHM) based on the image pyramid and tiling techniques. GRHM is a logical model that is independent upon physical storage. To support lightweight WMSs, we propose a physical storage structure, and deploy multi-dimensional RS data on Web servers. To further improve the performance of WMSs, a data declustering method based on Hilbert space-filling curve is adopted for the distributed storage. We also provide an Open Geospatial Consortium (OGC) WMS and a Web map system in Web browsers. Experiments conducted on real RS datasets show promising performance of the proposed lightweight WMSs.

ACTGIS: A Web-based collaborative tiled Geospatial image map system

In the past few years, the Web has become a de facto deployment environment for new application systems. Web-based Geospatial image map systems make satellite remote sensing data available to a wider range of public users than ever before. The storage and organization of global massive multi-dimensional remote sensing data have a big impact on the performance of Web mapping systems. To implement a performance-optimized Web mapping system, we propose a global grid division pyramid hierarchical data model for massive remote sensing data management, and adopt Hilbert curve allocation method for data placements. Collaborative web map browsing is also very important for many applications such as crisis management, military activities and government decision-making. However, realizing collaboration functionality on the basis of the stateless HTTP protocol, optimized for client requests, is not trivial. The limitations of the Webs request/response architecture prevent server from pushing real-time dynamic Web data. To address this problem, we propose a web-based interactive collaborative browsing framework based on server push technique (Comet). Moreover, we develop a prototype system called ACTGIS. Finally, we evaluate the prototype system using real remote sensing datasets, which demonstrate the good performance data access in our system.

SOCOM: A Service-Oriented Collaboration Middleware for Multi-User Interaction with Web Services based Scientific Resources

Scientific collaboration has become more and more important in current scientific research. A collaboration environment which simplifies integration and collaboration of heterogeneous scientific resources, for instance scientific computing software and scientific apparatuses, can accelerate progress of scientific research remarkably. We present a novel middleware to facilitate development of distributed and collaborative application for scientific research. A service-oriented collaboration bus is proposed to enable scientific resources to be plugged in and users to interact with these resources collaboratively and transparently. Collaboration bus engines in different organizations can interoperate with each other to support distributed collaboration. We also show our prototype implementation of this middleware and a demonstration of Collaborative Visualization System for Seismic Data in earth science.

Formal Analysis of Behavioural Equivalence for Trustworthy and Composite Web Services

Trustworthy and composite web services play important roles in service-oriented systems. Web services choreography as one important approach of composing web services describes the global model of service interactions among a set of participants. Bisimilar analysis that checks whether two choreographies are behavioural equivalent is an important verification approach for trustworthy composition. This paper discusses strong and weak bisimilarity of choreographies. Internal and external roles are distinguished from special roles that we hope to verify their observable behaviours. A language named Chor which is based on abstract syntax of WS-CDL is proposed to describe behaviours. In Chor, internal roles and internal activities among them are abstracted for their no effect on externally observable behaviour. A real example is presented to illustrate the usages and benefits of the formal analysis.

A Graph Transformation based Approach for Runtime Constrained Evolution of Service-Oriented Architectures

Service Oriented Architecture(SOA) is a new form of distributed software architecture. SOA promotes loose coupling, services distribution, dynamicity and agility. Services involved in an SOAare remote and autonomous services, the SOA designer can not control them and unpredictable behavior can occur. This makes the SO different from other architectures for its special architecture elements and its dynamic and evolving structure. How to model this specific architecture and support service-oriented development is unimportant research field in service-oriented software engineering community. This paper proposed a graph transformation based approach to model SOA and its evolution at runtime. Graph grammar is used tore present the architectural style, type and structural constraints are introduced to improve the robustness and adaptability when reconfiguring the architectures at runtime.

SSCM: middleware for structure-based service collaboration

The collaboration of services scattered over the internet is often required in solving a complicated scientific problem or finishing a complex business process. Centralized client/server architecture used in traditional service collaboration mechanism such as workflow has exhibited many weaknesses. We adopt the concept from peer-to-peer computing and Synergetics, and introduce an innovative middleware for structured-based service collaboration, in which each service node belongs to one or more structured collaboration organizations and is allowed to join and leave (planned departure or sudden failure) freely. We also propose neighborhood-based maintenance mechanism to cope with the dynamics of collaboration organization structure in a decentralized manner.

Geospatial Web Service for Remote Sensing Data Visualization

The widely used geospatial web services technology has provided a new means for geospatial data interoperability. Web Map Service (WMS) is a standardized geospatial web service from the Open Geospatial Consortium (OGC). WMSs can be used for requesting and producing maps on the Internet, and have been widely adopted in the Geographic Information System (GIS) community. These WMSs make remote sensing data available to a wider range of public users than ever before. However, the performance of current OGC-Compatible WMS servers can not satisfy the need of massive remote sensing data visualization. To implement a performance-optimized WMS server, we propose a global remote sensing data hierarchical model based on tile imagery pyramid and quad tree techniques for data organization and index, and adopt Hilbert curve allocation method (HCAM) for data placement. On this basis, we implement an OGC compatible tiled WMS and a service wrapper for mapping WMS to Web Services. Finally, we evaluate the tiled WMS server using real remote sensing datasets. Experiment results demonstrate a high-performance data access.

OGC-compatible high-performance web map service for remote sensing data visualization

Web Map Service(WMS) is an Open Geospatial Consortium (OGC) data visualization service used for requesting and producing maps on the internet. OGC WMS has been widely adopted in the Geographic Information System (GIS) community. These WMSs make remote sensing data available to a wider range of public users than ever before. However, the performance of current WMS servers can not satisfy the need of massive remote sensing data visualization. To implement a performance-optimized WMS server, we propose a global remote sensing data hierarchical model based on image pyramid and tiling techniques for data organization. On this basis, we implement an OGC compatible tiled WMS service and a service wrapper for mapping WMSs to Web Services. Finally, we evaluate the tiled WMS server using real remote sensing datasets. Experiment results demonstrate a high-performance data access.

Collaborative geospatial web services for multi-dimension remote sensing data

Satellite remote sensing imagery data is an important Geospatial data which is playing an increasingly important role in many applications such as crisis management, military activities and Government decision-making. However, it will continue to be a great challenge to organize and manage these multi-dimension massive remote sensing data for collaborative visualization services in Internet environment. In this paper we proposed a hierarchical directory structure based on tiling and pyramid technologies for the organization and management of multi-source and multi-scale remote sensing data. We implemented a collaborative Geospatial data visualization system based on our proposed storage structure using Web Services, WSRF and Web2.0 technologies. Finally, we evaluated the prototype system with real data sets, which demonstrated the high performance data access in our system.