Automatic geospatial metadata generation for earth science virtual data products

Recent advances in Semantic Web and Web Service technologies has shown promise for automatically deriving geospatial information and knowledge from Earth science data distributed over the Web. In a service-oriented environment, the data, information, and knowledge are often consumed or produced by complex, distributed geoscientific workflows or service chains. In order for the chaining results to be consumable, sufficient metadata for data products to be delivered by service chains must be provided. This paper proposes automatic generation of geospatial metadata for Earth science virtual data products. A virtual data product is represented using process models, and can be materialized on demand by dynamically binding and chaining archived data and services, as opposed to requiring that Earth science data products be physically archived. Semantics-enabled geospatial metadata is generated, validated, and propagated during the materialization of a virtual data product. The generated metadata not only provides a context in which end-users can interpret data products before intensive execution of service chains, but also assures semantic consistency of the service chains.     

Service-oriented middleware: A survey

Service-oriented computing aims to make services available and easily accessible through standardized models and protocols without having to worry about the underlying infrastructures, development models or implementation details. This helps achieve interoperability and loose coupling among distributed application components and also among user processes. In addition, this model offers users an on-demand usage model where they only use the services needed for the time needed, which relieves them from having to build and maintain a complete system in house. However, the design and implementation of robust and efficient service-oriented applications are still as complex and demanding as any other type of distributed application. Thus middleware can play an important role in facilitating the design, development and implementation of service-oriented systems. Furthermore, middleware approaches will provision non-functional requirements like performance, scalability, reliability, flexibility and quality of service (QoS) assurance. A lot of work has been done in this area and in this paper we survey some of this work in service-oriented middleware (SOM). As we study the different projects we develop a list of the main requirements that SOM should support. We also discuss the main objectives and characteristics of the surveyed approaches, and then we highlight the challenges to be addressed when designing and developing SOM solutions that satisfy the requirements of different application domains.     

Multi-model driven collaborative development platform for service-oriented e-Business systems

Enterprises need to be responsive to meet dynamic businesses and requirements. Service-oriented architecture and Web services can improve e-Business systems to be integrated and flexible. This paper proposes a multi-model driven collaborative development platform for service-oriented e-Business systems. The platform provides engineers/consultants with three views, i.e., business view, process view, and service view to support service-oriented software engineering, top-down business design and bottom-up service composite and development. The views are kept consistent through model-driven translation mechanisms. The platform employs three models, i.e., service meta-model, process model and business model to implement the translation. On the platform, business and technical consultants/engineers can use the views designated for their roles to collaborate for a service-oriented e-Business system based at the distributed sites of, e.g., IT vendors and their clients. The collaboration is featured with visual development and rapid demonstration. Comparingly, most of the mainstream development environments focus on object-oriented application development other than service-oriented business process modeling. The platform has been developed and deployed in an innovation centre to be evaluated by visiting customers.     

基于SOA的空间信息资源整合与服务模式探讨

提高空间信息资源的整合与服务水平,在迈向信息和服务型社会的过程中具有十分重要的意义。文章根据作者近年来在该领域的相关应用研究,对空间信息资源整合与服务模式进行了探讨,总结了基于SOA实现空间信息资源整合与服务的模式,并通过实例阐述了空间信息资源整合与服务的组织、实施和应用。     

Semantic Web-based geospatial knowledge transformation

Earth and space science research and applications typically involve collecting and analyzing large volumes of geospatial data much of which is derived from other existing data by applying a scientific workflow. Such a step-by-step process can be viewed as a process of geospatial knowledge transformation, which often involves hypotheses, inferences and integrations to derive user-specific data products from the knowledge of domain experts. Our research is focused on reducing the transformation effort by providing component inference and integration tools. The Semantic Web envisions a new standardized information infrastructure to enable interoperable machine-to-machine interactions and automatic or semi-automatic service chaining for deriving knowledge over networks. This paper describes a generic framework and implementation of how the Semantic Web proceeds through the life cycle of geospatial knowledge transformation, from geospatial modeling (knowledge formalization), through model instantiation (service chain) to model execution (data product). Our approach relies on semantic integrations. A number of ontologies used to capture domain knowledge are introduced in this paper as the basis of knowledge bases for describing and reasoning geospatial data and services. Also, a semantically enabled geospatial catalog service is described to enable more effective discovery, automation and integration of geospatial data and services.     

A model-driven framework for enterprise service management

With a steady pace of adoption of service-oriented architecture, enterprises have made significant progresses in implementing various kinds of Web services and converting existing applications to service-oriented architecture. As a significant number of services have been put into actual use, many service-oriented enterprises are faced with the problem of how to manage these services efficiently. In this paper, we propose a model-driven framework for a more efficient management of these services. In this framework, the creation and maintenance of enterprise integration solutions are modeled by flows, finite state machines (FSMs), role-based access control (RBAC) among other formal systems models as well as appropriate decision models. For instance, each enterprise integration solution would be modeled as composite services that can be described by respective flow, FSM and RBAC models. These solution models can then be stored, and later retrieved for the execution of these composite services. Furthermore, formal systems and decision models are also used to maintain and update these service-oriented solutions to improve the efficiency and quality of service management by taking advantage of the underlying service-oriented architecture.     

Ontological user modelling and semantic rule-based reasoning for personalisation of Help-On-Demand services in pervasive environments

Existing context-aware applications are limited in their support of user personalisation. Nevertheless, the increase in the use of context-aware technologies has sparked the growth in assistive applications resulting in a need to enable adaptation to reflect the changes in user behaviours. This paper introduces a systematic approach to service personalisation for mobile users in pervasive environments and presents a service-oriented distributed system architecture. The developed approach makes use of semantic technologies for user modelling and personalisation reasoning. In the paper we characterise user behaviours and needs in pervasive environments upon which ontological user models are created with special emphasis being placed on ontological modelling of dynamic and adaptive user profiles. We develop a rule-based personalisation mechanism that exploits semantic web rule mark-up language for rule design and a combination of semantic and rule-based reasoning for personalisation. We use two case studies focusing on providing personalised travel assistance for people using Help-on-Demand services deployed on a smart-phone to contextualise the discussions within the paper. The proposed approach is implemented in a prototype system, which includes Help-on-Demand services, content management services, user models and personalisation mechanisms in addition to application specific rules. Experiments have been designed and conducted to test and evaluate the approach with initial results demonstrating the functionality of the approach.     

Applying CIM-to-PIM model transformations for the service-oriented development of information systems

Context

Model-driven approaches deal with the provision of models, transformations between them and code generators to address software development. This approach has the advantage of defining a conceptual structure, where the models used by business managers and analysts can be mapped into more detailed models used by software developers. This alignment between high-level business specifications and the lower-level information technologies (ITs) models is crucial to the field of service-oriented development, where meaningful business services and process specifications are those relevant to real business scenarios.

Objective

This paper presents a model-driven approach which, starting from high-level computational-independent business models (CIMs) - the business view - sets out guidelines for obtaining lower-level platform-independent behavioural models (PIMs) - the information system view. A key advantage of our approach is the use of real high-level business models, not just requirements models, which, by means of model transformations, helps software developers to make the most of the business knowledge for specifying and developing business services.

Method

This proposal is framed in a method for service-oriented development of information systems whose main characteristic is the use of services as first-class objects. The method follows an MDA-based approach, proposing a set of models at different levels of abstraction and model transformations to connect them.

Results

The paper present the complete set of CIM and PIM metamodels and the specification of the mappings between them, which clear advantage is the support for the alignment between high-level business view and ITs. The proposed model-driven process is being implemented in an MDA tool. A first prototype has been used to develop a travel agency case study that illustrates the proposal.

Conclusion

This study shows how a model-driven approach helps to solve the alignment problem between the business view and the information system view that arises when adopting service-oriented approaches for software development.     

ARIS Method Extension for Business-Driven SOA

Service-oriented architecture (SOA) promises making companies more flexible enabling them to react quickly to changing market conditions. To leverage those advantages, SOA must be integrated with other existing approaches like business process management and enterprise architecture management. The authors describe how they extended the enterprise architecture management and business process management modelling method ARIS. They first created a SOA meta model by abstracting from existing modelling methods as well as extracting expert knowledge through interviews. In a second step, they mapped the SOA meta model to ARIS to provide a concrete modelling language for service-oriented enterprises. The ARIS extension allows describing and governing service architectures, describing services, linking service development initiatives to projects and company strategy, and discovering services for business process automation.

A formal model for the interoperability of service clouds

Large-scale service-oriented computing is based on the idea that services from various servers are combined into one distributed application. Referring to a collection of services on one server as a ??service cloud??, the problem investigated in this paper is to define formal high-level specifications of such distributed applications and to enable the location of suitable services for them. Based on the language-independent model of Abstract State Services (AS²s), which serves as a universal integrated model for data and software as services, we extend AS²s by high-level action schemes called ??plots?? as a means to specify permitted sequences of service operations. On these grounds, we develop a model for service mediators, that is, specifications of composed services in which service slots have to be filled by actual services, and investigate matching conditions for slots of mediators and services. For a services to match a slot in a mediator, a (generalised) projection of the mediator must comply with the plot of the service. Furthermore, the service must be semantically adequate, which requires the use of a service ontology.     

面向服务的建模:一种全过程复用的方法

面向服务的计算是Internet环境下的一种新型软件架构理念,即通过集成分布的服务构建软件.面向服务建模是面向服务计算中的重要研究内容.一方面,面向服务的软件同传统软件一样,需要首先对应用需求进行建模.另一方面,面向服务的计算需要实现分布复用和快速集成,这对面向服务的建模提出了新的要求.文中提出一种基于全过程复用的面向服务的建模方法,即提出构建特定应用领域的本体系统,包含相互关联着的多个不同类型的本体.不同层次的软件资产关联到这些本体上,支持面向服务建模的不同阶段,包括应用框架建模、业务流程建模、合作模式建模以及组合服务建模等.当出现新的服务软件应用需求时,通过本体系统的引导复用软件资产,最后构造出服务软件模型.     

Automatic derivation of BPEL4WS from IDEF0 process models

Integration definition for function modelling (IDEF0) is one of the most popular notations for modelling business processes. It employs a rather simple and intuitive modelling construct, consisting of boxes representing functions and arrows connecting them signifying flow of information and materials. Web services on the other hand are an emerging technology for implementing distributed systems. Web service orchestration languages, such as Business Process Execution Language for Web Services (BPEL4WS), are the emerging approach for describing processes as networks of coordinated web services. Business processes as captured in IDEF0 models, however, may contain both web services as well as other types of activities which need to be coordinated. By automatically analysing the Extensible Markup Language (XML) definition of an IDEF0 model, we can identify how web services interact with other activities and at runtime generate code to support the orchestration of web services with the overall business process. The approach proposed is independent of the orchestration language and ensures an implementation independent model for specifying web service orchestrations. This approach also enables the top-down analysis of a business process to its constituent web services and avoids any misalignment problems during design time between the two.     

PolarHub: A large-scale web crawling engine for OGC service discovery in cyberinfrastructure

The advancement of geospatial interoperability research has fostered the proliferation of geospatial resources that are shared and made publicly available on the Web. However, their increasingly availability has made the identification of the web signature of voluminous geospatial resources a major challenge. In this paper, we introduce our solution of a new cyberinfrastructure platform, the PolarHub, that conducts large-scale web crawling to discover distributed geospatial data and service resources and accomplish this goal efficiently and effectively. The PolarHub is built-upon a service-oriented architecture (SOA) and adopts Data Access Object (DAO)-based software design pattern to ensure the extendibility of the software system. The proposed meta-search-based seed selection and pattern-matching based crawling strategy facilitates the rapid resource identification and discovery through constraining the search scope on the Web. In addition, PolarHub introduces the use of advanced asynchronous communication strategy, which combines client-pull and server-push to ensure high efficiency of the crawling system. These unique design features of PolarHub enable a high performance, scalable, sustainable, collaborative, and interactive platform for active geospatial data discovery. Because of OGC's widespread adoption, OGC-compliant web services become the primary search target of PolarHub. Currently, the PolarHub system is up and running and is serving various scientific community that demands geospatial data. We consider PolarHub a significant contribution to the field of information retrieval and geospatial interoperability.     

A process-mining-based scenarios generation method for SOA application development

Business process models which are usually constructed by business designers from experience and analysis are the main guidelines for services composition in the service-oriented architecture (SOA) applications development. However, due to the complexity of business models, it is a challenging task for business process designers to optimize the process models dynamically in accordance with changes in business environments. In this paper, a process-mining-based method is proposed to support business process designers to monitor efficiency or capture the changes of a business process. Firstly, we define a scenario model to depict business elements and their relationships which are critical to business process design. Based on the proposed scenario model, process mining algorithms, including control flow mining, roles mining and data flow mining are carried out in a certain sequence synthetically to extract business scenarios from event logs recorded by SOA application systems. Finally, we implement a prototype using a logistic scenario to illustrate the feasibility of our method in SOA applications development.     

基于Web Service的在线水文模型服务研究

通过分析目前水文模型本地服务模式的不足,针对当前国内外Web Service技术在水文信息系统中的应用现状,设计并实现了一个基于Web Service技术的在线水文模型服务系统,示范了基于Web Service技术的网络数据获取、水文模型运行模拟等过程,说明基于Web Service技术的在线水文模型服务较好地实现了水文模型网络共享,支持异地模型访问。建议在线水文模型服务结构从网络数据库/数据中心获取数据,一定程度上解决了传统模式从本机上传海量数据等问题。这种在线水文模型服务模式节约了模型运行成本、降低了用户要求,在具体水文水资源管理事务中具有较好的应用和拓展前景。