620 resultados para CNPQ::CIENCIAS EXATAS E DA TERRA::CIENCIA DA COMPUTACAO::METODOLOGIA E TECNICAS DA COMPUTACAO::ENGENHARIA DE SOFTWARE


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Many challenges have been imposed on the middleware to support applications for digital TV because of the heterogeneity and resource constraints of execution platforms. In this scenario, the middleware must be highly configurable so that it can be customized to meet the requirements of applications and underlying platforms. This work aims to present the GingaForAll, a software product line developed for the Ginga - the middleware of the Brazilian Digital TV (SBTVD). GingaForAll adds the concepts of software product line, aspect orientation and model-driven development to allow: (i) the specification of the common characteristics and variables of the middleware, (ii) the modularization of crosscutting concerns - both mandatory and concepts variables - through aspects, (iii) the expression of concepts as a set of models that increase the level of abstraction and enables management of various software artifacts in terms of configurable models. This work presents the architecture of the software product line that implements such a tool and architecture that supports automatic customization of middleware. The work also presents a tool that implements the process of generating products GingaForAll

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This paper presents a contribution to the international Verified Software Repository effort through the formal specification of the microkernel FreeRTOS real-time system. Such specification was made in abstract level making use of the B method . For thus, properties of the microkernel were chosen and selected as specification requisites, which was constructed centered at the functionalities responsible for the utilization of these properties. This properties weres setting as specification requirements. The specification was constructed modeling the function of microkernel that implement this properties. This work intended to encourage the formal verification of FreeRTOS and also contribute to the formal creation of a microkernel real-time systems, based in FreeRTOS. Furthermore, this model brings a formal documentation point view of the microkernel, demonstrating features and how this internal states is changing. Finally, this work could be an example of specification of the actual system by the B method.

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On the last years, several middleware platforms for Wireless Sensor Networks (WSN) were proposed. Most of these platforms does not consider issues of how integrate components from generic middleware architectures. Many requirements need to be considered in a middleware design for WSN and the design, in this case, it is possibility to modify the source code of the middleware without changing the external behavior of the middleware. Thus, it is desired that there is a middleware generic architecture that is able to offer an optimal configuration according to the requirements of the application. The adoption of middleware based in component model consists of a promising approach because it allows a better abstraction, low coupling, modularization and management features built-in middleware. Another problem present in current middleware consists of treatment of interoperability with external networks to sensor networks, such as Web. Most current middleware lacks the functionality to access the data provided by the WSN via the World Wide Web in order to treat these data as Web resources, and they can be accessed through protocols already adopted the World Wide Web. Thus, this work presents the Midgard, a component-based middleware specifically designed for WSNs, which adopts the architectural patterns microkernel and REST. The microkernel architectural complements the component model, since microkernel can be understood as a component that encapsulates the core system and it is responsible for initializing the core services only when needed, as well as remove them when are no more needed. Already REST defines a standardized way of communication between different applications based on standards adopted by the Web and enables him to treat WSN data as web resources, allowing them to be accessed through protocol already adopted in the World Wide Web. The main goals of Midgard are: (i) to provide easy Web access to data generated by WSN, exposing such data as Web resources, following the principles of Web of Things paradigm and (ii) to provide WSN application developer with capabilities to instantiate only specific services required by the application, thus generating a customized middleware and saving node resources. The Midgard allows use the WSN as Web resources and still provide a cohesive and weakly coupled software architecture, addressing interoperability and customization. In addition, Midgard provides two services needed for most WSN applications: (i) configuration and (ii) inspection and adaptation services. New services can be implemented by others and easily incorporated into the middleware, because of its flexible and extensible architecture. According to the assessment, the Midgard provides interoperability between the WSN and external networks, such as web, as well as between different applications within a single WSN. In addition, we assessed the memory consumption, the application image size, the size of messages exchanged in the network, and response time, overhead and scalability on Midgard. During the evaluation, the Midgard proved satisfies their goals and shown to be scalable without consuming resources prohibitively

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Nowadays several electronics devices support digital videos. Some examples of these devices are cellphones, digital cameras, video cameras and digital televisions. However, raw videos present a huge amount of data, millions of bits, for their representation as the way they were captured. To store them in its primary form it would be necessary a huge amount of disk space and a huge bandwidth to allow the transmission of these data. The video compression becomes essential to make possible information storage and transmission. Motion Estimation is a technique used in the video coder that explores the temporal redundancy present in video sequences to reduce the amount of data necessary to represent the information. This work presents a hardware architecture of a motion estimation module for high resolution videos according to H.264/AVC standard. The H.264/AVC is the most advanced video coder standard, with several new features which allow it to achieve high compression rates. The architecture presented in this work was developed to provide a high data reuse. The data reuse schema adopted reduces the bandwidth required to execute motion estimation. The motion estimation is the task responsible for the largest share of the gains obtained with the H.264/AVC standard so this module is essential for final video coder performance. This work is included in Rede H.264 project which aims to develop Brazilian technology for Brazilian System of Digital Television

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Using formal methods, the developer can increase software s trustiness and correctness. Furthermore, the developer can concentrate in the functional requirements of the software. However, there are many resistance in adopting this software development approach. The main reason is the scarcity of adequate, easy to use, and useful tools. Developers typically write code and test it. These tests usually consist of executing the program and checking its output against its requirements. This, however, is not always an exhaustive discipline. On the other side, using formal methods one might be able to investigate the system s properties further. Unfortunately, specification languages do not always have tools like animators or simulators, and sometimes there are no friendly Graphical User Interfaces. On the other hand, specification languages usually have a compiler which normally generates a Labeled Transition System (LTS). This work proposes an application that provides graphical animation for formal specifications using the LTS as input. The application initially supports the languages B, CSP, and Z. However, using a LTS in a specified XML format, it is possible to animate further languages. Additionally, the tool provides traces visualization, the choices the user did, in a graphical tree. The intention is to improve the comprehension of a specification by providing information about errors and animating it, as the developers do for programming languages, such as Java and C++.

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This dissertation aims at extending the JCircus tool, a translator of formal specifications into code that receives a Circus specification as input, and translates the specification into Java code. Circus is a formal language whose syntax is based on Z s and CSP s syntax. JCircus generated code uses JCSP, which is a Java API that implements CSP primitives. As JCSP does not implement all CSP s primitives, the translation strategy from Circus to Java is not trivial. Some CSP primitives, like parallelism, external choice, communication and multi-synchronization are partially implemented. As an aditional scope, this dissertation will also develop a tool for testing JCSP programs, called JCSPUnit, which will also be included in JCircus new version. The extended version of JCircus will be called JCircus 2.0.

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This work presents an ontology to describe the semantics of IMML (Interactive Message Modeling Language) an XML-based User Interface Description Language. The ontology presents the description of all IMML elements including a natural language description and semantic rules and relationships. The ontology is implemented in OWL-DL, a standard language to ontology description that is recommended by W3C. Our main goal is to describe the semantic using languages and tools that can be processed by computers. As a consequence, we develop tools to the validation of a user interface specification and also to present the semantic description in different views

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The main goal of this work is to investigate the suitability of applying cluster ensemble techniques (ensembles or committees) to gene expression data. More specifically, we will develop experiments with three diferent cluster ensembles methods, which have been used in many works in literature: coassociation matrix, relabeling and voting, and ensembles based on graph partitioning. The inputs for these methods will be the partitions generated by three clustering algorithms, representing diferent paradigms: kmeans, ExpectationMaximization (EM), and hierarchical method with average linkage. These algorithms have been widely applied to gene expression data. In general, the results obtained with our experiments indicate that the cluster ensemble methods present a better performance when compared to the individual techniques. This happens mainly for the heterogeneous ensembles, that is, ensembles built with base partitions generated with diferent clustering algorithms

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Software Product Line (SPL) consists of a software development paradigm, whose main focus is to identify features common and variability among applications in a specific domain. An LPS is designed to attend all products requirements from its product family. These requirements and LPS may have changes over time due to several factors, such as evolution of product requirements, evolution of the market, evolution of SLP process, evolution of the technologies used to develop the products. To handle these changes, LPS should be modified and evolve in order to not become obsolete, and adapt itself to new requirements. The Changes Impact Analysis is an activity that understand and identify what consequences these changes are cause on LPS. Impact Analysis on LPS may be supported by traceability relationships, which identify relationships between artefacts created during all phases of software development. Despite the solutions of change impact analysis based on traceability for software, there is a lack of solutions for assessing the change impact analysis based on traceability for LPS, since existing solutions do not include estimates specific to the artefacts of LPS. Thus, this paper proposes a process of change impact analysis and an tool for assessing the change impact through traceability of artefacts in LPS. For this purpose, we specified a process of change impact analysis that considers artifacts produced during the development of LPS. We have also implemented a tool which allows estimating and identifying artefacts and products of LPS affected from changes in other products, changes in class, changes in features, changes between releases of LPS and artefacts related to changes in core assets and variability. Finally, the results were evaluated through metrics

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Brazil is going through the process from analogical transmission to digital transmission. This new technology, in addition to providing a high quality audio and video, also allows applications to execute on television. Equipment called Set-Top Box are needed to allow the reception of this new signal and create the appropriate environment necessary to execute applications. At first, the only way to interact with these applications is given by remote control. However, the remote control has serious usability problems when used to interact with some types of applications. This research suggests a software resources implementation capable to create a environment that allows a smartphone to interact with applications. Besides this implementation, is performed a comparative study between use remote controle and smartphones to interact with applications of digital television, taking into account parameters related to usability. After analysis of data collected by the comparative study is possible to identify which device provides an interactive experience more interesting for users

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Product derivation tools are responsible for automating the development process of software product lines. The configuration knowledge, which is responsible for mapping the problem space to the solution space, plays a fundamental role on product derivation approaches. Each product derivation approach adopts different strategies and techniques to manage the existing variabilities in code assets. There is a lack of empirical studies to analyze these different approaches. This dissertation has the aim of comparing systematically automatic product derivation approaches through of the development of two different empirical studies. The studies are analyzed under two perspectives: (i) qualitative that analyzes the characteristics of approaches using specific criteria; and (ii) quantitative that quantifies specific properties of product derivation artifacts produced for the different approaches. A set of criteria and metrics are also being proposed with the aim of providing support to the qualitative and quantitative analysis. Two software product lines from the web and mobile application domains are targets of our study

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This work presents the concept, design and implementation of a MP-SoC platform, named STORM (MP-SoC DirecTory-Based PlatfORM). Currently the platform is composed of the following modules: SPARC V8 processor, GPOP processor, Cache module, Memory module, Directory module and two different modles of Network-on-Chip, NoCX4 and Obese Tree. All modules were implemented using SystemC, simulated and validated, individually or in group. The modules description is presented in details. For programming the platform in C it was implemented a SPARC assembler, fully compatible with gcc s generated assembly code. For the parallel programming it was implemented a library for mutex managing, using the due assembler s support. A total of 10 simulations of increasing complexity are presented for the validation of the presented concepts. The simulations include real parallel applications, such as matrix multiplication, Mergesort, KMP, Motion Estimation and DCT 2D

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This dissertation presents a model-driven and integrated approach to variability management, customization and execution of software processes. Our approach is founded on the principles and techniques of software product lines and model-driven engineering. Model-driven engineering provides support to the specification of software processes and their transformation to workflow specifications. Software product lines techniques allows the automatic variability management of process elements and fragments. Additionally, in our approach, workflow technologies enable the process execution in workflow engines. In order to evaluate the approach feasibility, we have implemented it using existing model-driven engineering technologies. The software processes are specified using Eclipse Process Framework (EPF). The automatic variability management of software processes has been implemented as an extension of an existing product derivation tool. Finally, ATL and Acceleo transformation languages are adopted to transform EPF process to jPDL workflow language specifications in order to enable the deployment and execution of software processes in the JBoss BPM workflow engine. The approach is evaluated through the modeling and modularization of the project management discipline of the Open Unified Process (OpenUP)

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The World Wide Web has been consolidated over the last years as a standard platform to provide software systems in the Internet. Nowadays, a great variety of user applications are available on the Web, varying from corporate applications to the banking domain, or from electronic commerce to the governmental domain. Given the quantity of information available and the quantity of users dealing with their services, many Web systems have sought to present recommendations of use as part of their functionalities, in order to let the users to have a better usage of the services available, based on their profile, history navigation and system use. In this context, this dissertation proposes the development of an agent-based framework that offers recommendations for users of Web systems. It involves the conception, design and implementation of an object-oriented framework. The framework agents can be plugged or unplugged in a non-invasive way in existing Web applications using aspect-oriented techniques. The framework is evaluated through its instantiation to three different Web systems

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Through the adoption of the software product line (SPL) approach, several benefits are achieved when compared to the conventional development processes that are based on creating a single software system at a time. The process of developing a SPL differs from traditional software construction, since it has two essential phases: the domain engineering - when common and variables elements of the SPL are defined and implemented; and the application engineering - when one or more applications (specific products) are derived from the reuse of artifacts created in the domain engineering. The test activity is also fundamental and aims to detect defects in the artifacts produced in SPL development. However, the characteristics of an SPL bring new challenges to this activity that must be considered. Several approaches have been recently proposed for the testing process of product lines, but they have been shown limited and have only provided general guidelines. In addition, there is also a lack of tools to support the variability management and customization of automated case tests for SPLs. In this context, this dissertation has the goal of proposing a systematic approach to software product line testing. The approach offers: (i) automated SPL test strategies to be applied in the domain and application engineering, (ii) explicit guidelines to support the implementation and reuse of automated test cases at the unit, integration and system levels in domain and application engineering; and (iii) tooling support for automating the variability management and customization of test cases. The approach is evaluated through its application in a software product line for web systems. The results of this work have shown that the proposed approach can help the developers to deal with the challenges imposed by the characteristics of SPLs during the testing process