Página 6 dos resultados de 3715 itens digitais encontrados em 0.055 segundos

## Proposal of convergence of e-Learning systems for t-Learning

Franco, B. B.; Oliveira, H. C.; Rodolpho, E. R.
Tipo: Artigo de Revista Científica Formato: 27-31
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This article presents considerations about viability on reutilize existing web based e-Learning systems on Interactive Digital TV environment according to Digital TV standard adopted in Brazil. Considering the popularity of Moodle system in academic and corporative area, such system was chosen as a foundation for a survey into its properties to create a specification of an Application Programming Interface (API) for convergence to t-Learning characteristics that demands efforts in interface design area due the fact that computer and TV concepts are totally different. This work aims to present studies concerning user interface design during two stages: survey and detail of functionalities from an e-Learning system and how to adapt them for the Interactive TV regarding usability context and Information Architecture concepts.

## Design and evaluation of the Hamal parallel computer

Grossman, J. P., 1973-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 152 p.; 5345143 bytes; 5344524 bytes; application/pdf; application/pdf
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Parallel shared-memory machines with hundreds or thousands of processor-memory nodes have been built; in the future we will see machines with millions or even billions of nodes. Associated with such large systems is a new set of design challenges. Many problems must be addressed by an architecture in order for it to be successful; of these, we focus on three in particular. First, a scalable memory system is required. Second, the network messaging protocol must be fault-tolerant. Third, the overheads of thread creation, thread management and synchronization must be extremely low. This thesis presents the complete system design for Hamal, a shared-memory architecture which addresses these concerns and is directly scalable to one million nodes. Virtual memory and distributed objects are implemented in a manner that requires neither inter-node synchronization nor the storage of globally coherent translations at each node. We develop a lightweight fault-tolerant messaging protocol that guarantees message delivery and idempotence across a discarding network. A number of hardware mechanisms provide efficient support for massive multithreading and fine-grained synchronization.; (cont.) Experiments are conducted in simulation, using a trace-driven network simulator to investigate the messaging protocol and a cycle-accurate simulator to evaluate the Hamal architecture. We determine implementation parameters for the messaging protocol which optimize performance. A discarding network is easier to design and can be clocked at a higher rate...

## Eventing architecture : RFID and sensors in supply chain

Emery, Kevin E. (Kevin Eric)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: [61] leaves; 2817238 bytes; 2818930 bytes; application/pdf; application/pdf
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We propose data structures to describe and query streaming RFID and sensor data. Furthermore, we propose an architecture built atop these data structures to build arbitrary real-time applications. To understand the nature of these applications, we decompose such systems into four layers: Physical, Data, Filtering, and Application. We describe each layer in terms of our presented data structures, and we discuss architecture optimizations in terms of Bandwidth, Computational Capacity, and Subsystem Transparency. We provide an implementation of Track and Trace and Cold-Chain model applications to demonstrate our architecture.; by Kevin E. Emery.; Thesis (M. Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.; Unpaged.; Includes bibliographical references (leaf [61]).

## A region-based architecture for service-providing distributed systems

Singh, Neha, S.M. Massachusetts Institute of Technology
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 136 leaves; 7186971 bytes; 7192654 bytes; application/pdf; application/pdf
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A service-providing system consists of hosts that provide services such as data, content, computational and memory resources and data-based services to other entities in the system. Consumers that wish to use services describe their needs with a set of high-level objectives. In this thesis, we address the problem of locating services in a large-scale distributed system using their descriptions, rather than their addresses. We propose a network architecture that is based on the concept of dividing the service-providing hosts into Regions. A Region is a grouping of elements of the network that share a set of common characteristics and policies. Members of a region manage their interactions with other regions and their elements according to some defined rules and policies. Hosts can be divided into regions based on various properties such as their content, their commercial model or their security characteristics to name a few. The service provided by a region is an aggregate of the services provided by all its member hosts. The region-based architecture routes a service request through the network efficiently based on its description and on the advertisements from regions providing services. Division of hosts into a set of independent regions partitions the search space and produces a scalable structure.; (cont.) The architecture also does not impose any rules on the internal organization of regions making the system flexible and dynamic.; by Neha Singh.; Thesis (S.M.)--Massachusetts Institute of Technology...

## Embedding methods for massing and detail design in computer generated design of skyscrapers

Chen, Shouheng, S.M. Massachusetts Institute of Technology
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 155 p.; 43738533 bytes; 43738039 bytes; application/pdf; application/pdf
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This thesis proposes a new digital system to construct the massing and details of skyscrapers. It extracts underlying rules and design conventions from significant projects in contemporary skyscraper design practice. These rules and conventions are translated into digital data and embedded in a system. The thesis demonstrates how to use this system to reconstruct original designs as well as to generate new ones by means of transformation rules. It takes examples from the built skyscraper projects of Cesar Pelli and Associates as well as Norman Foster and Partners, and embeds their conventions and components to illustrate an implementation of such a system. In contemporary skyscraper design, sophisticated computer models are constructed in advanced engineering systems for the use of engineering analysis, but they contribute very little to the conceptual design of skyscrapers.; (cont.) The goal of this thesis is to propose embedded methods as an alternative approach and to develop a digital system that can both handle complex forms and enable architects to work more efficiently in the early stages of the design process. The intention behind building such a system is to relieve architects from the repetitive work that is required by conventional CAD systems as well as to allow them to carry their previous expertise--well-established stylistic conventions and approved components--into the design of new skyscrapers.; by Shouheng Chen.; Thesis (S.M.)--Massachusetts Institute of Technology...

## Relational agents : effecting change through human-computer relationships

Bickmore, Timothy W
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 284 p.
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What kinds of social relationships can people have with computers? Are there activities that computers can engage in that actively draw people into relationships with them? What are the potential benefits to the people who participate in these human-computer relationships? To address these questions this work introduces a theory of Relational Agents, which are computational artifacts designed to build and maintain long-term, social-emotional relationships with their users. These can be purely software humanoid animated agents--as developed in this work--but they can also be non-humanoid or embodied in various physical forms, from robots, to pets, to jewelry, clothing, hand-helds, and other interactive devices. Central to the notion of relationship is that it is a persistent construct, spanning multiple interactions; thus, Relational Agents are explicitly designed to remember past history and manage future expectations in their interactions with users. Finally, relationships are fundamentally social and emotional, and detailed knowledge of human social psychology--with a particular emphasis on the role of affect--must be incorporated into these agents if they are to effectively leverage the mechanisms of human social cognition in order to build relationships in the most natural manner possible. People build relationships primarily through the use of language...

## Flexible MIPS soft processor architecture

Carli, Roberto
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 49 p.
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The flexible MIPS soft processor architecture borrows selected technologies from high-performance computing to deliver a modular, highly customizable CPU targeted towards FPGA implementations for embedded systems; the objective is to provide a more flexible architectural alternative to coprocessor-based solutions. The processor performs out-of-order execution on parallel functional units, it delivers in -order instruction commit and it is compatible with the MIPS-1 Instruction Set Architecture. Amongst many available options, the user can introduce custom instructions and matching functional units; modify existing units; change the pipelining depth within functional units to any fixed or variable value; customize instruction definitions in terms of operands, control signals and register file interaction; insert multiple redundant functional units for improved performance. The flexibility provided by the architecture allows the user to expand the processor functionality to implement instructions of coprocessor-level complexity through additional functional units. The processor design was implemented and simulated on two FPGA platforms, tested on multiple applications, and compared to three commercially available soft processor solutions in terms of features...

## Introducing tool support for managing architectural knowledge: an experienced report, engineering computer based systems

Ali Babar, Muhammad; Northway, Andrew; Gorton, Ian; Heuer, Paul; Nguyen, Thong
Fonte: IEEE Computer Society Publicador: IEEE Computer Society
Tipo: Conference item; all_ul_research; ul_published_reviewed; none
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peer-reviewed; Management of software architecture knowledge is vital for improving an organisation’s architectural capabilities. Despite the recognition of the importance of capturing and reusing software architecture knowledge, there is currently no suitable support mechanism available. To address this issue, we have developed a conceptual framework for managing architecture design knowledge. A web-based knowledge management tool, Process-based Architecture Knowledge Management Environment (PAKME), has been developed to support that framework. PAKME is being trialled to help systematise the architecture knowledge management and evaluation process of an industrial collaborator. This paper reports the objectives, logistics and initial findings of this project, Specifically we have deployed and used PAKME in an Australian Defence acquisition environment for evaluating architecture of a aircraft system.

## An epistemological basis for alignment in Enterprise Architecture views

Chemboli, Srinivas
Fonte: Computer Society of India (CSI) Publicador: Computer Society of India (CSI)
Tipo: Conference paper Formato: 6 pages
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In several Enterprise Architectures (EA), the views at the CXO-levels may often be at variance with the views provided to mid-tier and operations levels. As a result of this misalignment, organizations may not be able to fully realize the intended enhancements to business management. Alignment of architecture views with one another, as well as consistency with the overall architecture description of the enterprise can be achieved by developing an epistemological basis for enterprise architecture management. In this paper, an approach to develop such a basis is proposed through use of Omnispective Analysis and Reasoning (OAR), an epistemic framework for managing intellectual concerns. This approach focuses on ensuring that the representation of enterprise concerns captures the necessary information regarding their applicability, correctness and completeness for a given problem scenario, and facilitates development of localized ontologies for describing the behavior of component systems and the interactions between them. An example of architecture view alignment is presented to illustrate the approach.; Computer Society of India (CSI)

## Distributed Handler Architecture

Yildiz, Beytullah
Fonte: [Bloomington, Ind.] : Indiana University Publicador: [Bloomington, Ind.] : Indiana University
Tipo: Doctoral Dissertation
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Thesis (PhD) - Indiana University, Computer Sciences, 2007; Over the last couple of decades, distributed systems have been demonstrated an architectural evolvement based on models including client/server, multi-tier, distributed objects, messaging and peer-to-peer. One recent evolutionary step is Service Oriented Architecture (SOA), whose goal is to achieve loose-coupling among the interacting software applications for scalability and interoperability. The SOA model is engendered in Web Services, which provide software platforms to build applications as services and to create seamless and loosely-coupled interactions. Web Services utilize supportive functionalities such as security, reliability, monitoring, logging and so forth. These functionalities are typically provisioned as handlers, which incrementally add new capabilities to the services by building an execution chain. Even though handlers are very important to the service, the way of utilization is very crucial to attain the potential benefits. Every attempt to support a service with an additive functionality increases the chance of having an overwhelmingly crowded chain: this makes Web Service fat. Moreover, a handler may become a bottleneck because of having a comparably higher processing time. In this dissertation...

## The Rational Behavior software architecture for intelligent ships: an approach to mission and motion control

Byrnes, Ronald B.; Healey, Anthony J.; McGhee, Robert B.; Nelson, Michael L.; Kwak, Se-Hung; Brutzman, Donald P.
Fonte: Naval Engineers Journal Publicador: Naval Engineers Journal
Tipo: Artigo de Revista Científica
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The solutions to the power projection, transportation, and operational needs of the Navy as it faces the 21st century must account for reduced manning levels. This leads naturally to incrreased use of computers, automation and intelligent systems in the concept and design on the next generation of ships. In addition to the acknowledged hardware needs, the problem of autonomic and autonomous control of shipboard systems and missions are amenable to and will, in fact, require software solutions. Despite current technology, large reliable software systems are difficult to achieve because correctness in requirements analysis, design implementation, testing, modification and maintenance of software are difficult. Software is also difficult to quantize and display; hence, the effort and costs involved in its development are easily underestimated. This paper describes an approach to the problem of providing structure, in the form of a software architecture, to the software performing autonomous control of missions and their related tasks. In concert with the need to reduce complexity, the architecture must support simple, rapid reconfiguration of code should vehicle capabilities or mission requirements change. Building upon recent efforts with control of Autonomous Underwater Vehicles (AUVs)...

## Um modelo de arquitectura de Sistemas de Informação

Macedo, Bruno Armindo Rodrigues de Sousa
Fonte: Instituto Superior de Economia e Gestão Publicador: Instituto Superior de Economia e Gestão
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## IAX-Based Peer-to-Peer VoIP Architecture

Lazzez, Amor; Fredj, Ouissem Ben; Slimani, Thabet
Tipo: Artigo de Revista Científica
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Nowadays, Voice over IP (VoIP) constitutes a privileged field of service innovation. One benefit of the VoIP technology is that it may be deployed using a centralized or a distributed architecture. One of the most efficient approaches used in the deployment of centralized VoIP systems is based on the use of IAX (Inter-Asterisk Exchange), an open-source signaling/data exchange protocol. Even though they are currently widely used, client-server VoIP systems suffer from many weaknesses such as the presence of single points of failure, an inefficient resources management, and system non-scalability. In order to help the development of scalable and reliable VoIP systems, the development community starts tending towards the deployment of the VoIP service using a peer-to-peer distributed architecture. The aim of this paper is to develop an IAX-based peer-to-peer VoIP architecture, an optimized VoIP architecture that takes advantage of the benefits of the IAX protocol and those of the peer-to-peer distribution model.; Comment: 11 pages, 2 figures

## Efficient Super-Peer-Based Queries Routing: Simulation and Evaluation

Ismail, Anis; Quafafou, Mohamed; Nachouki, Gilles; Hajjar, Mohammad
Tipo: Artigo de Revista Científica
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Peer-to-peer (P2P) Data-sharing systems now generate a significant portion of internet traffic. P2P systems have emerged as a popular way to share huge volumes of data. Requirements for widely distributed information systems supporting virtual organizations have given rise to a new category of P2P systems called schema- based. In such systems each peer is a database management system in itself, ex-posing its own schema. A fundamental problem that confronts peer-to-peer applications is the efficient location of the node that stores a desired data item. In such settings, the main objective is the efficient search across peer databases by processing each incoming query without overly consuming bandwidth. The usability of these systems depends on effective techniques to find and retrieve data; however, efficient and effective routing of content- based queries is an emerging problem in P2P networks. In this paper, we propose an architecture, based on super-peers, and we focus on query routing. Our approach considers that super-Peers having similar interests are grouped together for an efficient query routing method. In such groups, called Knowledge-Super-Peers (KSP), super-peers submit queries that are often processed by members of this group.; Comment: Journal of Emerging Technologies in Web Intelligence...

## Design, Analysis and Evaluation of Control Algorithms for Applications in Smart Grids

Hinrichs, Christian; Sonnenschein, Michael
Tipo: Artigo de Revista Científica
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In many countries, the currently observable transformation of the power supply system from a centrally controlled system towards a complex "system of systems", comprising lots of autonomously interacting components, leads to a significant amount of research regarding novel control concepts. To facilitate the structured development of such approaches regarding the criticality of the targeted system, the research and development of a distributed control concept is demonstrated by employing an integrated methodology comprising both the Smart Grids Architecture Model framework (SGAM) and the Smart Grid Algorithm Engineering process model (SGAE). Along the way, a taxonomy of evaluation criteria and evaluation methods for such approaches is presented. For the whole paper, the Dynamic Virtual Power Plants business case (DVPP) serves as motivating example.

## FIPA-based Interoperable Agent Mobility Proposal

Cucurull, Jordi; Marti, Ramon; Robles, Sergi; Borrell, Joan; Navarro, Guillermo
Tipo: Artigo de Revista Científica
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This paper presents a proposal for a flexible agent mobility architecture based on IEEE-FIPA standards and intended to be one of them. This proposal is a first step towards interoperable mobility mechanisms, which are needed for future agent migration between different kinds of platforms. Our proposal is presented as a flexible and robust architecture that has been successfully implemented in the JADE and AgentScape platforms. It is based on an open set of protocols, allowing new protocols and future improvements to be accommodated in the architecture. With this proposal we demonstrate that a standard architecture for agent mobility capable of supporting several agent platforms can be defined and implemented.; Comment: 10 pages, agent migration architecture proposal

## Data Distribution Optimization using Offline Algorithms and a Peer-to-Peer Small Diameter Tree Architecture with Bounded Node Degrees

Andreica, Mugurel Ionut; Tirsa, Eliana-Dina; Tapus, Nicolae
Tipo: Artigo de Revista Científica
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Multicast data transfers occur in many distributed systems and applications (e.g. IPTV, Grids, content delivery networks). Because of this, efficient multicast data distribution optimization techniques are required. In the first part of this paper we present a small diameter, bounded degree, collaborative peer-to-peer multicast tree architecture, which supports dynamic node arrivals and departures making local decisions only. The architecture is fault tolerant and, at low arrival and departure rates, converges towards a theoretically optimal structure. In the second part of the paper we consider several offline data distribution optimization problems, for which we present novel and time-efficient algorithmic solutions.

## An Efficient List Decoder Architecture for Polar Codes

Lin, Jun; Yan, Zhiyuan
Tipo: Artigo de Revista Científica
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Long polar codes can achieve the symmetric capacity of arbitrary binary-input discrete memoryless channels under a low complexity successive cancelation (SC) decoding algorithm. However, for polar codes with short and moderate code length, the decoding performance of the SC algorithm is inferior. The cyclic redundancy check (CRC) aided successive cancelation list (SCL) decoding algorithm has better error performance than the SC algorithm for short or moderate polar codes. In this paper, we propose an efficient list decoder architecture for the CRC aided SCL algorithm, based on both algorithmic reformulations and architectural techniques. In particular, an area efficient message memory architecture is proposed to reduce the area of the proposed decoder architecture. An efficient path pruning unit suitable for large list size is also proposed. For a polar code of length 1024 and rate $\frac{1}{2}$, when list size $L=2$ and 4, the proposed list decoder architecture is implemented under a TSMC 90nm CMOS technology. Compared with the list decoders in the literature, our decoder achieves 1.33 to 1.96 times hardware efficiency.; Comment: 12 pages, accepted by IEEE TVLSI Systems

## End-User Effects of Microreboots in Three-Tiered Internet Systems

Candea, George; Fox, Armando
Tipo: Artigo de Revista Científica