Policies for Web Services

Web services are predominantly used to implement service-oriented architectures (SOA). However, there are several areas such as temporal dimensions, real-time, streaming, or efficient and flexible file transfers where web service functionality should be extended. These extensions can, for example, be achieved by using policies. Since there are often alternative solutions to provide functionality (e.g., different protocols can be used to achieve the transfer of data), the WS-Policy standard is especially useful to extend web services with policies. It allows to create policies to generally state the properties under which a service is provided and to explicitly express alternative properties. To extend the functionality of web services, two policies are introduced in this thesis: the Temporal Policy and the Communication Policy. The temporal policy is the foundation for adding temporal dimensions to a WS-Policy. The temporal policy itself is not a WS-Policy but an independent policy language that describes temporal dimensions of and dependencies between temporal policies and WS-Policies. Switching of protocol dependencies, pricing of services, quality of service, and security are example areas for using a temporal policy. To describe protocol dependencies of a service for streaming, real-time and file transfers, a communication policy can be utilized. The communication policy is a concrete WS-Policy. With the communication policy, a service can expose the protocols it depends on for a communication after its invocation. Thus, a web service client knows the protocols required to support a communication with the service. Therefore, it is possible to evaluate beforehand whether an invocation of a service is reasonable. On top of the newly introduced policies, novel mechanisms and tools are provided to alleviate service use and enable flexible and efficient data handling. Furthermore, the involvement of the end user in the development process can be achieved more easily. The Flex-SwA architecture, the first component in this thesis based on the newly introduced policies, implements the actual file transfers and streaming protocols that are described as dependencies in a communication policy. Several communication patterns support the flexible handling of the communication. A reference concept enables seamless message forwarding with reduced data movement. Based on the Flex-SwA implementation and the communication policy, it is possible to improve usability - especially in the area of service-oriented Grids - by integrating data transfers into an automatically generated web and Grid service client. The Web and Grid Service Browser is introduced in this thesis as such a generic client. It provides a familiar environment for using services by offering the client generation as part of the browser. Data transfers are directly integrated into service invocation without having to perform data transmissions explicitly. For multimedia MIME types, special plugins allow the consumption of multimedia data. To enable an end user to build applications that also leverage high performance computing resources, the Service-enabled Mashup Editor is presented that lets the user combine popular web applications with web and Grid services. Again, the communication policy provides descriptive means for file transfers and Flex-SwAs reference concept is used for data exchange. To show the applicability of these novel concepts, several use cases from the area of multimedia processing have been selected. Based on the temporal policy, the communication policy, Flex-SwA, the Web and Grid Service Browser, and the Service-enabled Mashup Editor, the development of a scalable service-oriented multimedia architecture is presented. The multimedia SOA offers, among others, a face detection workflow, a video-on-demand service, and an audio resynthesis service. More precisely, a video-on-demand service describes its dependency on a multicast protocol by using a communication policy. A temporal policy is then used to perform the description of a protocol switch from one multicast protocol to another one by changing the communication policy at the end of its validity period. The Service-enabled Mashup Editor is used as a client for the new multicast protocol after the multicast protocol has been switched. To stream single frames from a frame decoder service to a face detection service (which are both part of the face detection workflow) and to transfer audio files with the different Flex-SwA communication patterns to an audio resynthesis service, Flex-SwA is used. The invocation of the face detection workflow and the audio resynthesis service is realized with the Web and Grid Service Browser

NoSQL Data Stores In Publish/Subscribe-Based RESTful Web Services

In the era of mobile cloud computing, the consumption of virtualized software and Web-based services from super-back-end infrastructure using smartphones and tablets is gaining much research attention from both the industry and academia. Nowadays, these mobile devices generate and access multimedia data hosted in social media and other sources in order to enhance the users’ multimedia experience. However, multimedia data is unstructured which can lead to challenges with data synchronization between these mobile devices and the cloud computing back-end. The issue with data synchronization is further fueled by the fact that mobile devices can experience intermittent connectivity losses due to unstable wireless bandwidths. While previous works proposed Simple Object Access Protocol (SOAP) -based middleware for the Web services’ synchronization, this approach is not efficient in a mobile environment because the SOAP protocol is verbose. Thus, the Representational State Transfer (REST) standard has been proposed recently to model the Web services since it is lightweight. This thesis proposes a novel approach for implementing a REST-based mobile Web Service for multimedia file sharing that utilizes a channel-based publish/subscribe communication scheme to synchronize smartphone or tablet-hosted NoSQL databases with a cloud-hosted NoSQL database. This thesis evaluates the synchronicity and the scalability of a prototype system that was implemented according to this approach. Also, this thesis assesses the overhead of the middleware component of the system

Implementing a distributed lecture-on-demand multimedia presentation system

[[abstract]]Lecture-on-demand (LOD) multimedia presentation technologies in networks are most often used in communication services. Examples of those applications include video-on demand, interactive TV and communication tools in a distance learning system, etc. In this paper, we describe how to present different multimedia objects on a Web-based presentation system. The distributed approach is based on an extended timed Petri net model. Using characterization of extended media streaming technologies, we developed a Web-based multimedia presentation system. For a real-world example, suppose a well-known teacher is giving a lecture/presentation to his students. Because of time constraints and other commitments, many students cannot attend the presentation. The main goal of our system is to provide a feasible method to record and represent a lecture/presentation. Using a browser with windows media services allows those students to view live video of the teacher giving his speech, along with synchronized images of his presentation slides and all the annotations/comments. In our experience, this approach is sufficient for distance learning environments.[[notice]]補正完畢[[conferencetype]]國際[[conferencedate]]20020702~20020705[[conferencelocation]]Vienna, Austri

Developing an accessible video player

Online Channels in financial institutions allows customers with disabilities to access services in a convenient way for them. However, one of the current challenges of this sector is to improve web accessibility and to incorporate technological resources to provide access to multimedia and video content, which has become a new form of internet communication. The present work shows in detail the strategy followed when designing and developing the new video player used by Bankinter for these purposes.Peer Reviewe

Dynamic service composition for telecommunication services and its challenges

As communication networks have evolved towards IP (Internet Protocol) networks, telecommunication operators has expanded its reach to internet multimedia web content services while operating circuit-switch networks in parallel. With the adoption of SOA (Service Oriented Architecture) that enables service capability interfaces to be published and integrated with other service capabilities into new composite service, service composition allows telecommunication providers to accelerate more new services provisioning. From the perspective of telecommunication providers to deliver integrated composite service from different providers and different network protocols, this paper is aimed to present the current service composition based on middleware approaches; discuss the requirements of meeting the challenges; and compare the approaches

Bringing context-aware access to the web through spoken interaction

The web has become the largest repository of multimedia information and its convergence with telecommunications is now bringing the benefits of web technology to hand-held devices. To optimize data access using these devices and provide services which meet the user needs through intelligent information retrieval, the system must sense and interpret the user environment and the communication context. In addition, natural spoken conversation with handheld devices makes possible the use of these applications in environments in which the use of GUI interfaces is not effective, provides a more natural human-computer interaction, and facilitates access to the web for people with visual or motor disabilities, allowing their integration and the elimination of barriers to Internet access. In this paper, we present an architecture for the design of context-aware systems that use speech to access web services. Our contribution focuses specifically on the use of context information to improve the effectiveness of providing web services by using a spoken dialog system for the user-system interaction. We also describe an application of our proposal to develop a context-aware railway information system, and provide a detailed evaluation of the influence of the context information in the quality of the services that are supplied.Research funded by projects CICYT TIN2011-28620-C02-01, CICYT TEC 2011-28626-C02-02, CAM CONTEXTS (S2009/TIC-1485), and DPS2008-07029-C02-02.Publicad

Developing SOA wrappers for communication purposes in rural areas

The introduction of Web Services as a platform upon which applications can communicate has contributed a great deal towards the expansion of World Wide Web technologies. The Internet and computing technologies have been some of the factors that have contributed to the socio-economic improvement of urban and industrial areas. This research focuses on the application of Service-Oriented Architecture (SOA) and Web Services technologies in Information and Communication Technologies for Development (ICT4D) contexts. SOA is a style used to design distributed systems, and Web Services are some of the common realizations of the SOA. Web Services allow the exchange of data between two or more machines in a simple and standardized manner over the network. This has resulted in the augmentation of ways in which individuals in a society and in the world communicate. This research aims to develop a SOA-based system with services that are implemented as Web Services. The system is intended to support communication activities of Dwesa community members. The communication methods identified as the most commonly used in the Dwesa community are Short Message Services (SMSs) and voice calls. In this research we have identified further methods (i.e. Multimedia Message Service, Electronic mail and Instant Messaging) to augment communication activities in Dwesa. The developed system, therefore, exposes SMS Web Service, MMS Web Service, Email Web Service and IM Web Service that are consumed in machine-to-machine, machine-to-person and person-to-person types of communication. We have also implemented a one-stop communication shop, through a web portal which provides interfaces to the different communication modules. Elaborate functional and usability testing have also been undertaken to establish the viability and end-user acceptance of the system respectively. This research has provided the initial validation of the effectiveness of the SOA-based system in ICT4D context