Cássio V. S. Prazeres

Semantic Web Services Discovery and Composition: Paths Along Workflows

Semantic Web Services discovery and composition: paths along workflows Web Services allow the composition of new services on top of existing, partial ones. Using standard languages, Semantic Web Services can provide the description of their input parameters and preconditions for execution, as well as the output and effects of their execution. The availability of such descriptions demand the investigation of systematic approaches for the composition of Web Services based on their description. After presenting our approach for service discovery, we detail our proposal for modeling the composition problem using graphs. Next, we present the algorithm we implemented for the composition of Web Services, detailing the cost-based policy underlying our graph-based model. We also present the results of experiments we executed based on artificial data describing Web Services.

Documenting the pen-based interaction

Pen-based interaction allows users to register information using a variety of devices such as PDAs, Tablet PCs or electronic whiteboards. As a result, users have the opportunity to review the information by means of a document that represents the final, static, result. Alternatively, users may be able to play back the digital ink using, for instance, the same application used for capture.However, considering the context in which pen-based ink is usually used -- e.g. meetings or lectures -- there is an important opportunity for a user to review intermediary views of the pen-based interaction. For instance, it may be relevant for a student to produce a printable version of a particular diagram presented by an instructor so that the several steps used in the construction of the diagram are made explicit. Similarly, it may be imperative for the instructor to be able to identify the steps taken by a student while making notes during a laboratory session, for example.We have defined operations that model the user-interaction during digital ink capture and implemented the operations in an Web-based application that allows reviewing documents created automatically as a result of the user-interaction with electronic whiteboards or Tablets PCs. The operations may be exploited in many situations were it is important to have a detailed and customized report of users writing activity.

Remote Experiments as SemanticWeb Services

Online experimentation allows users to operate remote instruments from anywhere and, usually, at any time. The amount of experiments that can be accessed trough the Web is growing quickly. These remote experiments have distinct characteristics, need a variety of resources, as well as present different availability and access procedures. Remote experiments can be supported as Semantic Web Services, demanding special attention in terms of discovering, selection, composition, scheduling, monitoring and making available the results. In order to allow the integration of remote experiments in Web-based environments, we propose supporting remote experiments as semantic Web services. Our approach, which we call RALOWS - remote access laboratory ontology and Web service, reuse and extend known ontologies to provide formal description for experiments. More specifically, we combine temporal concepts to service and resource descriptions so as to make possible to specify scheduling and to impose restrictions in the use of the resources involved in the experimentation.Service oriented computing has significantly changed the style of designing software for distributed communication systems. However, the promise to loosen the dependencies of application components to allow the usage of any functionally equivalent services was only kept in part. The emergence of expressive semantic descriptions of services, the consequent adaptation of service matching, and the introduction of autonomic service composition concepts meant a real step towards openness and reusability. Semantic markup languages describing service interfaces, characteristics, and functionality, paired with inference and advanced querying methods facilitated situation-aware service adaptation and rapid service creation. However, most of todays solutions for the semantic enhancement of service architectures are tied to specific application domains and do crucially increase the development complexity. For this reason, our work indicates approaches aiming at light-weight semantic service descriptions, their autonomous creation, and adaptation. Moreover, simplified service descriptions address a broader range of computing devices, including those with limited physical capabilities, e.g., regarding their available processing power and memory capacity. Finally, we address decentralized methods for the progressive creation and adaptation of service descriptions utilizing novel interaction models.

A structured document-based approach for Weblab configuration

WebLabs allow experiments and associated resources to be accessed and controlled via the web. We contribute with XML Schemas and transformations for WebLab description and experiment configuration that are the basis for the document-based I-TOOLARR system. The I-TOOLARR system makes use of XSLT transformations to automatically generate (a) XML Schemas defining configuration information and (b) form-based interfaces that allow users to configure WebLabs in general and specific experiments in particular.

Semantic Web Services Discovery by Matching Temporal Restrictions

Matching algorithms for semantic Web services discovery focus on the functional aspects of the services, which are usually given by the function that transforms inputs into outputs. Current approaches do not take into attention the fact that some services may not be available around the clock and, more restrictively, may require exclusive access. In this paper we present an approach to allow the discovery of Web Services based on properties and temporal restrictions. We present a matching algorithm which leverages the work reported on the literature so as to consider availability matching. Throughout the paper, we illustrate our approach in the context of Web services related to remote experiments, which may present rigid constraints in terms of both temporal restrictions and availability of resources.

Web of Things Gateway: a Performance Evaluation

The Web of Things is a proposal to make physical and connected devices available to be used as resources in the development of Web applications through the Web protocols and standards. On the one hand, the current Web has virtual content, which is accessed by client applications that are hosted on Web servers, but on the other hand, the physical devices are real objects that are geographically distributed and have several different ways of communication. As a result of these two before-mentioned characteristics, the physical devices would demand a larger number of Web servers. In this context, this work proposes that devices with limited memory capacity and processing power can be used as Web of Things gateways through Web protocols. Then, performance evaluation of such limited device is presented in this paper with two evaluation objectives: to evaluate the feasibility of a limited device as a Web of Things gateway; to establish the capacity of the gateway in management the access to the physical devices.

Web of Things: Automatic Publishing and Configuration of Devices

The Web of Things proposes to make devices available by using Web standards and protocols. Several different devices, which can be connected to the Web of Things, demand efforts to implement specific services to deploy each of such devices. For that reason, this paper presents an approach to automatically publish and configure devices as Web of Things resources. Our approach presents models that implement device functionalities and uses such models to automatically generate Web Services for devices. This paper also presents: i) dynamic discovery and configuration of devices when connecting to a local network by using Zeroconf protocol; ii) automatic generation of applications for publishing devices on the Web of Things.

Semantic web services: from OWL-S via UML to MVC applications

OWL-S is used to describe the semantics of Web Services so that the discovery, selection, invocation and composition of these services can be automated. Prior research has shown that UML diagrams can be used to automatically generate Semantic Web Service descriptions in OWL-S. If complete Web applications could be generated from OWL-S descriptions, then a higher level of automation would be achieved. In this paper, we propose an approach for processing OWLS descriptions in order to produce MVC-based skeletons for Web applications. The OWL-S ontology goes through a series of transformations in order to generate an application whose Model-View-Controller structure is implemented by a combination of JavaBeans/JSP/Servlets code, respectively.

Design and implementation of a message-service oriented middleware for fog of things platforms

Fog of Things (FoT) is a new paradigm for design and implementation of Fog Computing platforms for the Internet of Things (IoT). The FoT proposal goes further than the Fog Computing in some directions: i) by using all the processing capacity of the network edge through performing data processing and service delivery on devices, gateways (very small servers) and small local servers; ii) by defining profiles for gateways and servers at the edge of the network, in order to define and implement IoT Services to be delivered in a distributed way; iii) by distributing these IoT Services also at the network edge through a message-service oriented middleware. In this paper, we propose FoT-MSOM, which is a message-service oriented middleware for the FoT paradigm, and we show how this middleware can be deployed on a Self-Organizing FoT-based platform (SOFT-IoT platform).

An Extensible Platform to Evaluate Semantic Web Services Automatic Composition Approaches

The problem of automatically composing Web Services that can match clients request has been the focus of several researchers. However, only a small number of such studies have evaluated and compared these different techniques on equal terms. Generally, these techniques have been evaluated on an ad hoc basis. This article presents a platform for evaluating the different techniques for the automatic composition of Semantic Web Services. The proposed platform provides: (i) an extensible architecture that enables the inclusion and evaluation of different techniques; (ii) a suite of metrics aimed at evaluating these techniques.