Página 1 dos resultados de 3715 itens digitais encontrados em 0.156 segundos

Prototyping an information centric architecture for opportunistic networks

Morais, Nelson da Silva Teigas
Fonte: Repositório Científico Lusófona Publicador: Repositório Científico Lusófona
Tipo: Dissertação de Mestrado
ENG
Relevância na Pesquisa
55.66%
A arquitetura atual das redes informáticas, que serve de suporte à maioria dos sistemas de informação, assenta num modelo de comunicações ponto a ponto e no qual a informação é transmitida em pacotes de dados que contêm informação sobre a origem e o destino dos mesmos. Este paradigma não se ajusta às necessidades de processamento de informação com que nos deparamos diariamente nos dias de hoje. Atualmente, a informação é ubíqua e os meios de acesso à mesma são efetuados cada vez mais com recurso a dispositivos móveis que comunicam sobre redes intermitentes ou pouco estáveis. A última década tem sido propícia ao aparecimento de propostas baseadas em novas formas de distribuição e acesso à informação com base em redes movidas pelo conteúdo da própria informação. Esta tese analisa uma dessas propostas e utiliza-a como base para a criação de um protótipo de uma rede desse tipo, direcionada para sistemas que operam em multiplataformas e sobre redes oportunistas.; The current architecture of computer networks, which supports the majority of information systems, is based on a model of peer to peer communications and in which information is transmitted using data packets that contain information about its origin and destination. This paradigm does not fit the needs of information processing that we face every day nowadays. Currently...

Business process and software architecture model co-evolution patterns

Jamshidi, Pooyan; Pahl, Claus
Fonte: IEEE Computer Society Publicador: IEEE Computer Society
Tipo: info:eu-repo/semantics/conferenceObject; all_ul_research; ul_published_reviewed
ENG
Relevância na Pesquisa
65.58%
peer-reviewed; Software systems are subject to change. To embrace change, the systems should be equipped with automated mechanisms. Business process and software architecture models are two artifacts that are subject to change in an interrelated manner that requires them co-evolve. As opposed to the traditional batch-based model transformation, we propose a comprehensive set of structural and behavioral evolution patterns that enable to incrementally reflect the impact of change of business processes to their associated architecture models by applying reusable patterns. A basis for automation is provided through a graph-based formalism.

Scheduling Medical Application Workloads on Virtualized Computing Systems

Delgado, Javier
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
Relevância na Pesquisa
65.47%
This dissertation presents and evaluates a methodology for scheduling medical application workloads in virtualized computing environments. Such environments are being widely adopted by providers of “cloud computing” services. In the context of provisioning resources for medical applications, such environments allow users to deploy applications on distributed computing resources while keeping their data secure. Furthermore, higher level services that further abstract the infrastructure-related issues can be built on top of such infrastructures. For example, a medical imaging service can allow medical professionals to process their data in the cloud, easing them from the burden of having to deploy and manage these resources themselves. In this work, we focus on issues related to scheduling scientific workloads on virtualized environments. We build upon the knowledge base of traditional parallel job scheduling to address the specific case of medical applications while harnessing the benefits afforded by virtualization technology. To this end, we provide the following contributions: An in-depth analysis of the execution characteristics of the target applications when run in virtualized environments. A performance prediction methodology applicable to the target environment. A scheduling algorithm that harnesses application knowledge and virtualization-related benefits to provide strong scheduling performance and quality of service guarantees. In the process of addressing these pertinent issues for our target user base (i.e. medical professionals and researchers)...

A Regression Approach to Execution Time Estimation for Programs Running on Multicore Systems

Alshamlan, Mohammad
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
Relevância na Pesquisa
65.67%
Execution time estimation plays an important role in computer system design. It is particularly critical in real-time system design, where to meet a deadline can be as important as to ensure the logical correctness of a program. To accurately estimate the execution time of a program can be extremely challenging, since the execution time of a program varies with inputs, the underlying computer architectures, and run-time dynamics, among other factors. The problem becomes even more challenging as computing systems moving from single core to multi-core platforms, with more hardware resources shared by multiple processing cores. The goal of this research is to investigate the relationship between the execution time of a program and the underlying architecture features (e.g. cache size, associativity, memory latency), as well as its run-time characteristics (e.g. cache miss ratios), and based on which, to estimate its execution time on a multi-core platform based on a regression approach. We developed our test platform based on GEM5, an open-source multi-core cycle-accurate simulation tool set. Our experimental results show clearly the strong relationship of the program execution time to architecture features and run-time characteristics. Moreover...

Design and Development of Geographical Information System (GIS) Map for Nuclear Waste Streams

Appunni, Sandhya
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
Relevância na Pesquisa
65.52%
A nuclear waste stream is the complete flow of waste material from origin to treatment facility to final disposal. The objective of this study was to design and develop a Geographic Information Systems (GIS) module using Google Application Programming Interface (API) for better visualization of nuclear waste streams that will identify and display various nuclear waste stream parameters. A proper display of parameters would enable managers at Department of Energy waste sites to visualize information for proper planning of waste transport. The study also developed an algorithm using quadratic Bézier curve to make the map more understandable and usable. Microsoft Visual Studio 2012 and Microsoft SQL Server 2012 were used for the implementation of the project. The study has shown that the combination of several technologies can successfully provide dynamic mapping functionality. Future work should explore various Google Maps API functionalities to further enhance the visualization of nuclear waste streams.

Fuzzy Modeling and Control Based Virtual Machine Resource Management

Wang, Lixi
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
Relevância na Pesquisa
65.44%
Virtual machines (VMs) are powerful platforms for building agile datacenters and emerging cloud systems. However, resource management for a VM-based system is still a challenging task. First, the complexity of application workloads as well as the interference among competing workloads makes it difficult to understand their VMs’ resource demands for meeting their Quality of Service (QoS) targets; Second, the dynamics in the applications and system makes it also difficult to maintain the desired QoS target while the environment changes; Third, the transparency of virtualization presents a hurdle for guest-layer application and host-layer VM scheduler to cooperate and improve application QoS and system efficiency. This dissertation proposes to address the above challenges through fuzzy modeling and control theory based VM resource management. First, a fuzzy-logic-based nonlinear modeling approach is proposed to accurately capture a VM’s complex demands of multiple types of resources automatically online based on the observed workload and resource usages. Second, to enable fast adaption for resource management, the fuzzy modeling approach is integrated with a predictive-control-based controller to form a new Fuzzy Modeling Predictive Control (FMPC) approach which can quickly track the applications’ QoS targets and optimize the resource allocations under dynamic changes in the system. Finally...

Behavior Models and Composition for Software and Systems Architecture

Auguston, Mikhail; Clifford Whitcomb
Fonte: Escola de Pós-Graduação Naval Publicador: Escola de Pós-Graduação Naval
Relevância na Pesquisa
75.58%
ICSSEA 2012, 24th International Conference on SOFTWARE & SYSTEMS ENGINEERING and their APPLICATIONS, Telecom ParisTech, Paris, October 23-25, 2012; This paper suggests an approach to formal software and systems architecture specification based on behavior models. The behavior of a system is defined as a set of events (event trace) with two basic relations: precedence and inclusion. The structure of an event trace is specified using event grammars and other constraints organized into schemas. Behaviors for both system and its environment can be specified within the same framework. Suggested composition operations on schemas are based on event pattern matching and provide for behavior merging and abstract interface specification. The schema framework is amenable to stepwise refinement, reuse, visualization of multiple architecture views, and application of automated tools for consistency checks and system behavior verification early in the design process.

Improvement of Heterogeneous Systems Efficiency Using Self-Configurable FPGA-based Computing

Melnyk, Anatolity; Melnyk, Viktor
Fonte: Universidade Carlos III de Madrid Publicador: Universidade Carlos III de Madrid
Tipo: info:eu-repo/semantics/publishedVersion; info:eu-repo/semantics/bookPart; info:eu-repo/semantics/conferenceObject
Publicado em /11/2014 ENG
Relevância na Pesquisa
55.65%
Computer systems performance is is being improved today using two major approaches: general-purpose computers computing power increase (creation of multicore processors, multiprocessor computer systems, supercomputers), and adaptation of the computer hardware to the executed algorithm (class of algorithms). Last approach often provides application of the ASIC-based and FPGA-based hardware accelerators, also called reconfigurable, and is characterized by better performance / power consumption ratio and lower cost as compared to the general-purpose computers of equivalent performance. However, such systems have typical problems. The ASIC-based accelerators: 1) are effective for certain classes of algorithms only and 2) algorithms and software require adaptation for effective application. The FPGA-based accelerators and reconfigurable computer systems (that use FPGAs as a processing unit): 1) in the process of writing require a special program to perform computing tasks balancing between the general-purpose computer and FPGAs; 2) require designing the application-specific processor soft-cores; and 3) are effective for certain classes of problems only, for which application-specific processor soft-cores were previously developed. In this paper...

Chameleon C2HDL Design Tool In Self-Configurable Ultrascale Computer Systems Based On Partially Reconfigurable FPGAs

Melnyk, Anatoliy; Melnyk, Viktor; Tsyhylyk, Lyubomyr
Fonte: Universidade Carlos III de Madrid Publicador: Universidade Carlos III de Madrid
Tipo: info:eu-repo/semantics/publishedVersion; info:eu-repo/semantics/bookPart; info:eu-repo/semantics/conferenceObject
Publicado em /10/2015 ENG
Relevância na Pesquisa
55.63%
The FPGA-based accelerators and reconfigurable computer systems based on them require designing the applicationspecific processors soft-cores and are effective for certain classes of problems only, for which these soft-cores were previously developed. In Self-Configurable FPGA-based Computer Systems the challenge of designing the application-specific processors soft-cores is solved with use of the C2HDL tools, allowing them to be generated automatically. In this paper, we study the questions of the self-configurable computer systems efficiency increasing with use of the partially reconfigurable FPGAs and Chameleonc C2HDL design tool, corresponding to the goals of the project entitled "Improvement of heterogeneous systems efficiency using self-configurable FPGA-based computing" which is a part of the NESUS action. One of the features of the Chameleonc C2HDL design tool is its ability to generate a number of application-specific processors soft-cores executing the same algorithm that differ by the amount of FPGA resources required for their implementation. If the self-configurable computer systems are based on partially reconfigurable FPGAs, this feature allows them to acquire in every moment of its operation such a configuration that will provide an optimal use of its reconfigurable logic at a given level of hardware multitasking.; Proceedings of: Second International Workshop on Sustainable Ultrascale Computing Systems (NESUS 2015). Krakow (Poland)...

Implications of Services-Oriented Architecture and Open Architecture composable systems on the acquisition organizations and processes

Brummett, Cory S.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: xvi, 77 p. : ill. ;
Relevância na Pesquisa
55.71%
The U.S. Navy is interested in acquiring systems that promote the use of Services-oriented Architecture (SOA) and Open Architecture (OA) in Integrated Warfare Systems (IWS). The number of systems required to share data and provide reliable information in weapons systems is growing. Many systems, systems-of-systems and families of systems with different software architectures are acquired and often have difficulty operating together, which causes delays, increases costs, and limits re-use. Intelligent adoption of SOA and OA may help solve integration and reuse issues in current and future acquisition programs. The commercial market is successfully beginning to implement SOA and OA in their processes and may provide examples of best practices that can be applied to the Defense Acquisition System. The goal of this thesis is to explore the feasibility of implementing SOA and OA into the Defense Acquisition System. Adoption of SOA and OA practices is not expected to completely alter the current Defense Acquisition System; instead, it is intended to alleviate some of its constraints. This thesis will focus on utilizing SOA and OA in IWS, how SOA and OA principles relate, and the effects they will have on the Defense Acquisition System's organizations and processes.; US Navy (USN) author.

Monterey Phoenix: modeling software and systems architecture

Auguston, Mikhail
Fonte: Monterey, California, Naval Postgraduate School Publicador: Monterey, California, Naval Postgraduate School
Tipo: Outros
Relevância na Pesquisa
75.61%
One of the major concerns in System and Software Architecture design is the question of the behavior of the system. For system's architeture one of the challenges is to predict emerging behavior of systems or systems. We suggest an approach for building system behavior models based on the concepts of event and event traces and tools for architecture verification.

A Fault Management System (FMS) architecture for the Naval Computer and Telecommunicatons Area Master Stations (NCTAMS)

Creighton, Kathleen M.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado
ENG
Relevância na Pesquisa
75.67%
Approved for public release; distribution is unlimited; The Joint Fleet Telecommunications Operations Center (JFTOC) acts, on behalf of the Naval Computer and Telecommunications Command, as the fleet's "one-stop shop" for information services. Effective fault management is vital to ensuring reliable network service. Currently, however, the JFTOC employs a Fault Management System (FMS) that consists primarily of manual processes and non- networked resources. Users require a system that provides a centralized and accessible source of near-real time fault management information. This thesis uses the methodology of the Department of Defense (DoD) Technical Architecture Framework for Information Management (TAFIM). TAFIM outlines a structured approach for migrating legacy systems to a open systems, standards-based target architecture. Through application of the TAFIM process, a target FMS architecture, termed HelpDesk On-Line Information System (HOLIS), is developed. HOLIS includes: the existing NCTAMS classified local area network and SIPRNet infrastructure; network operating system, office automation, e-mail and database software from the interim Navy Automated information System Standards list; and commercial off-the-shelf help desk software. Four migration paths are outlined...

On the Design of Real-Time Systems on Multi-Core Platforms under Uncertainty

WANG, TIANYI
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
Relevância na Pesquisa
65.59%
Real-time systems are computing systems that demand the assurance of not only the logical correctness of computational results but also the timing of these results. To ensure timing constraints, traditional real-time system designs usually adopt a worst-case based deterministic approach. However, such an approach is becoming out of sync with the continuous evolution of IC technology and increased complexity of real-time applications. As IC technology continues to evolve into the deep sub-micron domain, process variation causes processor performance to vary from die to die, chip to chip, and even core to core. The extensive resource sharing on multi-core platforms also significantly increases the uncertainty when executing real-time tasks. The traditional approach can only lead to extremely pessimistic, and thus, unpractical design of real-time systems. Our research seeks to address the uncertainty problem when designing real-time systems on multi-core platforms. We first attacked the uncertainty problem caused by process variation. We proposed a virtualization framework and developed techniques to optimize the system's performance under process variation. We further studied the problem on peak temperature minimization for real-time applications on multi-core platforms. Three heuristics were developed to reduce the peak temperature for real-time systems. Next...

Beyond analysis and representation in CAD : a new computational approach to design education; Beyond analysis and representation in computer-aided design

Celani, Maria Gabriela Caffarena
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 202 p.; 43114181 bytes; 43113940 bytes; application/pdf; application/pdf
ENG; ENG
Relevância na Pesquisa
55.66%
This thesis aims at changing students' attitude towards the use ofcomputer-aided design (CAD) in architecture. It starts from the premise that CAD is used mostly for analysis and representation, and not as a real design aide, and that architecture students have a bias against learning computer programming. For this purpose, a prototypical instruction system that mixes computer-aided design and computational design theory was developed, based on a series of fundamental concepts that are common to both fields. This system was influenced by Mitchell's (1987) The Art of Computer Graphics Programming and Stiny's (1976) shape grammars. Despite being based on solid theoretical foundations, CAD has progressively become an exclusively practical tool, since its origins in the 50's and 60's, while computational design theories have been mostly restricted to the academic circles. This thesis proposes an inversion in the present situation: the study of CAD theory, and the application of computational design into practice. The system proposed provides a conceptual framework that can be adapted to different circumstances, including course formats and resources, as well as students' background and technical training.; (cont.) It is based on seven fundamental concepts from computational design theories that are also important to the study of shape grammars: symmetry...

LUNES: Agent-based Simulation of P2P Systems (Extended Version)

D'Angelo, Gabriele; Ferretti, Stefano
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
55.61%
We present LUNES, an agent-based Large Unstructured NEtwork Simulator, which allows to simulate complex networks composed of a high number of nodes. LUNES is modular, since it splits the three phases of network topology creation, protocol simulation and performance evaluation. This permits to easily integrate external software tools into the main software architecture. The simulation of the interaction protocols among network nodes is performed via a simulation middleware that supports both the sequential and the parallel/distributed simulation approaches. In the latter case, a specific mechanism for the communication overhead-reduction is used; this guarantees high levels of performance and scalability. To demonstrate the efficiency of LUNES, we test the simulator with gossip protocols executed on top of networks (representing peer-to-peer overlays), generated with different topologies. Results demonstrate the effectiveness of the proposed approach.; Comment: Proceedings of the International Workshop on Modeling and Simulation of Peer-to-Peer Architectures and Systems (MOSPAS 2011). As part of the 2011 International Conference on High Performance Computing and Simulation (HPCS 2011)

Introduction to Distributed Systems

Thampi, Sabu M.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 23/11/2009
Relevância na Pesquisa
55.66%
Computing has passed through many transformations since the birth of the first computing machines. Developments in technology have resulted in the availability of fast and inexpensive processors, and progresses in communication technology have resulted in the availability of lucrative and highly proficient computer networks. Among these, the centralized networks have one component that is shared by users all the time. All resources are accessible, but there is a single point of control as well as a single point of failure. The integration of computer and networking technologies gave birth to new paradigm of computing called distributed computing in the late 1970s. Distributed computing has changed the face of computing and offered quick and precise solutions for a variety of complex problems for different fields. Nowadays, we are fully engrossed by the information age, and expending more time communicating and gathering information through the Internet. The Internet keeps on progressing along more than a few magnitudes, abiding end systems increasingly to communicate in more and more different ways. Over the years, several methods have evolved to enable these developments, ranging from simplistic data sharing to advanced systems supporting a multitude of services. This article provides an overview of distributed computing systems. The definition...

Eliminating Network Protocol Vulnerabilities Through Abstraction and Systems Language Design

Casey, C. Jasson; Sutton, Andrew; Reis, Gabriel Dos; Sprintson, Alex
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 13/11/2013
Relevância na Pesquisa
65.52%
Incorrect implementations of network protocol message specifications affect the stability, security, and cost of network system development. Most implementation defects fall into one of three categories of well defined message constraints. However, the general process of constructing network protocol stacks and systems does not capture these categorical con- straints. We introduce a systems programming language with new abstractions that capture these constraints. Safe and efficient implementations of standard message handling operations are synthesized by our compiler, and whole-program analysis is used to ensure constraints are never violated. We present language examples using the OpenFlow protocol.

Semantic Gateway as a Service architecture for IoT Interoperability

Desai, Pratikkumar; Sheth, Amit; Anantharam, Pramod
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 18/10/2014
Relevância na Pesquisa
55.66%
The Internet of Things (IoT) is set to occupy a substantial component of future Internet. The IoT connects sensors and devices that record physical observations to applications and services of the Internet. As a successor to technologies such as RFID and Wireless Sensor Networks (WSN), the IoT has stumbled into vertical silos of proprietary systems, providing little or no interoperability with similar systems. As the IoT represents future state of the Internet, an intelligent and scalable architecture is required to provide connectivity between these silos, enabling discovery of physical sensors and interpretation of messages between things. This paper proposes a gateway and Semantic Web enabled IoT architecture to provide interoperability between systems using established communication and data standards. The Semantic Gateway as Service (SGS) allows translation between messaging protocols such as XMPP, CoAP and MQTT via a multi-protocol proxy architecture. Utilization of broadly accepted specifications such as W3C's Semantic Sensor Network (SSN) ontology for semantic annotations of sensor data provide semantic interoperability between messages and support semantic reasoning to obtain higher-level actionable knowledge from low-level sensor data.; Comment: 16 pages

The failure tolerance of mechatronic software systems to random and targeted attacks

Kasthurirathna, Dharshana; Dong, Andy; Piraveenan, Mahendrarajah; Tumer, Irem Y.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 27/09/2013
Relevância na Pesquisa
55.68%
This paper describes a complex networks approach to study the failure tolerance of mechatronic software systems under various types of hardware and/or software failures. We produce synthetic system architectures based on evidence of modular and hierarchical modular product architectures and known motifs for the interconnection of physical components to software. The system architectures are then subject to various forms of attack. The attacks simulate failure of critical hardware or software. Four types of attack are investigated: degree centrality, betweenness centrality, closeness centrality and random attack. Failure tolerance of the system is measured by a 'robustness coefficient', a topological 'size' metric of the connectedness of the attacked network. We find that the betweenness centrality attack results in the most significant reduction in the robustness coefficient, confirming betweenness centrality, rather than the number of connections (i.e. degree), as the most conservative metric of component importance. A counter-intuitive finding is that "designed" system architectures, including a bus, ring, and star architecture, are not significantly more failure-tolerant than interconnections with no prescribed architecture, that is...

Exploring Hidden Coherent Feature Groups and Temporal Semantics for Multimedia Big Data Analysis

Yang, Yimin
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: text Formato: application/pdf
Relevância na Pesquisa
65.45%
Thanks to the advanced technologies and social networks that allow the data to be widely shared among the Internet, there is an explosion of pervasive multimedia data, generating high demands of multimedia services and applications in various areas for people to easily access and manage multimedia data. Towards such demands, multimedia big data analysis has become an emerging hot topic in both industry and academia, which ranges from basic infrastructure, management, search, and mining to security, privacy, and applications. Within the scope of this dissertation, a multimedia big data analysis framework is proposed for semantic information management and retrieval with a focus on rare event detection in videos. The proposed framework is able to explore hidden semantic feature groups in multimedia data and incorporate temporal semantics, especially for video event detection. First, a hierarchical semantic data representation is presented to alleviate the semantic gap issue, and the Hidden Coherent Feature Group (HCFG) analysis method is proposed to capture the correlation between features and separate the original feature set into semantic groups, seamlessly integrating multimedia data in multiple modalities. Next, an Importance Factor based Temporal Multiple Correspondence Analysis (i.e....