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Tolerância a falhas em robôs manipuladores cooperativos ; Fault tolerance in cooperative robotic manipulators

Tinós, Renato
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 30/01/2003 Português
Relevância na Pesquisa
66.61%
O problema da tolerância a falhas em robôs manipuladores cooperativos conectados rigidamente a um objeto indeformável é estudado nesta tese. A tolerância a falhas é alcançada através de reconfiguração do sistema de controle. Primeiro, a falha é detectada e isolada. Então, o sistema de controle é reconfigurado de acordo com a falha isolada. As falhas em robôs manipuladores são primeiramente estudadas de acordo com suas consequências no sistema cooperativo. Quatro tipos de falhas são identificados: juntas com balanço livre (sem atuadores ativos), bloqueadas, com informação incorreta de posição e com informação incorreta de velocidade. A detecção e a isolação dos dois primeiros tipos de falhas são alcançadas através de um sistema utilizando redes neurais artificiais. Redes do tipo MLP são empregadas para mapear a dinâmica dos robôs cooperativos sem falhas e uma rede RBF é utilizada para a classificação do vetor de resíduos. As falhas do tipo informação incorreta de posição ou velocidade das juntas são detectadas e isoladas através do uso das restrições impostas pela cadeia cinemática fechada presente no sistema cooperativo. Quando falhas do tipo juntas com balanço livre ou bloqueadas são isoladas...

Improving fault tolerance support in wireless sensor network macroprogramming; Evoluindo o suporte à tolerância a falhas na macroprogramação de redes de sensores sem fio

Nogueira, Guilherme de Maio
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 01/12/2014 Português
Relevância na Pesquisa
66.67%
Wireless Sensor Networks (WSN) are distributed sensing network systems composed of tiny networked devices. These systems are employed to develop applications for sensing and acting on the environment. Each network device, or node, is equipped with sensors and sometimes actuators as well. WSNs typically have limited power, processing, and storage capability, and are also subject to faults, especially when deployed in harsh environments. Given WSNs limitations, application developers often design fault-tolerance mechanisms. Although developers implement some fault-tolerance mechanisms in hardware, most are implemented in software. Indeed, WSN application development mostly occurs at a low level, close to the operating system, which forces developers to focus away from application logic and dive into WSNs technical background. Some have proposed high-level programming solutions, such as macroprogramming languages and frameworks; however, few deal with fault-tolerance. This dissertation aims to incorporate fault-tolerance features into Srijan, an open-source WSN macroprogramming framework based on a mixed declarative-imperative language called Abstract Task Graph (ATaG). We augment Srijans framework to support code generation for dealing with devices that crash or report meaningless values. We present our feature implementation here...

A reflective object-oriented architecture for developing fault-tolerant software

Buzato, Luiz Eduardo; Rubira, Cecilia Mary Fischer; Lisboa, Maria Lucia Blanck
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
Português
Relevância na Pesquisa
56.71%
This paper proposes a reflective object-oriented architecture for developing fault-tolerant software. Reflective object-oriented programming promotes a modular structuring of systems by means of a new dimension of modularization—the separation between base-level objects and meta-level objects. This property allows the creation of metaobjects responsible for managing tasks of application objects located at the base level. In the context of this work, computational reflection is applied to implement various strategies of fault tolerance at the meta-level in a transparent manner for the application programmer, that is, without interfering with the original structure of application objects that require fault tolerance facilities. The use of the proposed architecture has the following advantages: (i) separation of concerns, that is, separate the concerns related to the application domain from those related to the implementation of fault-tolerant mechanisms; (ii) it promotes code reuse of fault-tolerance mechanisms; (iii) it allows application programmers to use the most adequate fault-tolerance strategy for his implementation, and (iv) it provides a design that is more adaptable, flexible and easier to extend than traditional designs for developing fault-tolerant software. Our reflective architecture is composed of three levels...

An aspect-oriented approach to fault-tolerance in grid platforms

Medeiros, Bruno; Sobral, João Luís Ferreira
Fonte: Netbiblo Publicador: Netbiblo
Tipo: Conferência ou Objeto de Conferência
Publicado em //2011 Português
Relevância na Pesquisa
66.41%
Migrating traditional scientific applications to computational Grids requires programming tools that can help programmers to update application behaviour to this kind of platforms. Computational Grids are particularly suited for long running scientific applications, but they are also more prone to faults than desktop machines. The AspectGrid framework aims to develop methodologies and tools that can help to Grid-enable scientific applications, particularly focusing on techniques based on aspect-oriented programming. In this paper we present the aspect-oriented approach taken in the AspectGrid framework to address faults in computational Grids. In the proposed approach, scientific applications are enhanced with fault-tolerance capability by plugging additional modules. The proposed technique is portable across operating systems and minimises the changes required to base applications.

A heuristic for fault-tolerance provisioning in multi-radio hybrid wireless-optical broadband access network

Schutz, G.; Correia, Noélia
Fonte: IEEE Publicador: IEEE
Tipo: Conferência ou Objeto de Conferência
Publicado em //2009 Português
Relevância na Pesquisa
66.56%
The wireless-optical broadband-access network (WOBAN) architecture has been proposed as a flexible and cost-effective solution for future access networks. However, for WOBANs to provide geographically continuous wireless coverage it is necessary to integrate fault-tolerance in the design of such networks. In this paper we develop a heuristic algorithm to solve the problem of planning a wireless and optical fault-tolerant multi-radio WOBAN, considering any fault-tolerance scenario (e.g. some nodes/links/region only), while making an efficient reuse of spectrum.

A Reflective Object-Oriented Architecture for Developing Fault-Tolerant Software

Buzato,Luiz E.; Rubira,Cecília M. F.; Lisboa,Maria Lúcia B.
Fonte: Sociedade Brasileira de Computação Publicador: Sociedade Brasileira de Computação
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/1997 Português
Relevância na Pesquisa
56.71%
This paper proposes a reflective object-oriented architecture for developing fault-tolerant software. Reflective object-oriented programming promotes a modular structuring of systems by means of a new dimension of modularization—the separation between base-level objects and meta-level objects. This property allows the creation of metaobjects responsible for managing tasks of application objects located at the base level. In the context of this work, computational reflection is applied to implement various strategies of fault tolerance at the meta-level in a transparent manner for the application programmer, that is, without interfering with the original structure of application objects that require fault tolerance facilities. The use of the proposed architecture has the following advantages: (i) separation of concerns, that is, separate the concerns related to the application domain from those related to the implementation of fault-tolerant mechanisms; (ii) it promotes code reuse of fault-tolerance mechanisms; (iii) it allows application programmers to use the most adequate fault-tolerance strategy for his implementation, and (iv) it provides a design that is more adaptable, flexible and easier to extend than traditional designs for developing fault-tolerant software. Our reflective architecture is composed of three levels...

Model driven configuration of fault tolerance solutions for component-based software system

Wu, Yihan; Huang, Gang; Song, Hui; Zhang, Ying
Fonte: Springer Publicador: Springer
Tipo: info:eu-repo/semantics/conferenceObject; all_ul_research; ul_published_reviewed
Português
Relevância na Pesquisa
66.72%
peer-reviewed; Fault tolerance is very important for complex component-based software systems, but its configuration is complicated and challenging. In this paper, we propose a model driven approach to semi-automatic configuration of fault tolerance solutions. At design time, a set of reusable fault tolerance solutions are modeled as architecture styles, with the key properties verified by model checking. At runtime, the runtime software architecture of the target system is automatically constructed by the code generated from the given architectural meta-model. Then, the impact of each component on the system reliability is automatically analyzed to recommend which components should be considered in the fault tolerance configuration. Finally, after which components are guaranteed by what fault tolerance solution is decided by the system administration, the architecture model is automatically changed by merging with the selected fault tolerance styles and finally, these changes are automatically propagated to the target system. This approach is evaluated on Java enterprise systems.

Algorithmic fault tolerance using the Lanczos method

Boley, Daniel L; Brent, Richard P; Golub, Gene H; Luk, Franklin T
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Working/Technical Paper Formato: 202487 bytes; 356 bytes; application/pdf; application/octet-stream
Português
Relevância na Pesquisa
66.41%
We consider the problem of algorithm-based fault tolerance, and make two major contributions. First, we show how very general sequences of polynomials can be used to generate the checksums, so as to reduce the chance of numerical overows. Second, we show how the Lanczos process can be applied in the error location and correction steps, so as to save on the amount of work and to facilitate actual hardware implementation.; no

Fault Detection and Fault Tolerance Methods for Robotics

Visinsky, Monica L.; Visinsky, Monica L.
Fonte: Universidade Rice Publicador: Universidade Rice
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
56.69%
Masters Thesis; Fault tolerance is increasingly important in modern autonomous or industrial robots. The ability to detect and tolerate failures allows robots to effectively cope with internal failures and continue performing designated tasks without the need for immediate human intervention. To support these fault tolerant capabilities, methods of detecting and isolating failures must be perfected. This thesis presents new fault detection algorithms which detect failures in robot components using analytical redundancy relations. The robot components critical to fault detection are revealed using an extended fault tree analysis. The thesis validates the algorithms using a simulated robot failure testbed. An intelligent fault tolerance framework is proposed in which a fault tree database and the detection algorithms work together to detect and tolerate sensor or motor failures in a robot system. Future work will expand the detection and tolerance routines and embed the framework into a more exible expert system package.

Robotic Fault Tolerance: Algorithms and Architectures

Visinsky, Monica L.; Cavallaro, Joseph R.; Walker, Ian D.
Fonte: Prentice Hall, Englewood Cliffs, NJ Publicador: Prentice Hall, Englewood Cliffs, NJ
Tipo: Parte de Livro
Português
Relevância na Pesquisa
66.61%
Fault tolerance is an essential factor in ensuring successful autonomous systems, especially for robots working in remote or hazardous environments. To avoid the cost and risk involved in sending humans into these environs and improve the chances of mission success, robots must be able to quickly detect and recover from internal failures without relying on immediate repairs or human intervention. In developing robotic fault tolerance algorithms, the possible failures within the robot and the interdependence of these failures must first be determined. One useful tool for performing these tasks is Fault Tree Analysis. The tree structures developed by this technique provide a flow chart of possible robot fault events and define the cause and effect relationships between the failures.

A Survey of NASA and Military Standards on Fault Tolerance and Reliability Applied to Robotics

Cavallaro, Joseph R.; Walker, Ian D.
Fonte: NASA Publicador: NASA
Tipo: Conference paper
Português
Relevância na Pesquisa
66.52%
There is currently increasing interest and activity in the area of reliability and fault tolerance for robotics. This paper discusses the application of Standards in robot reliability, and surveys the literature of relevant existing standards. A bibliography of relevant Military and NASA standards for reliability and fault tolerance is included.

Robot Fault Detection and Fault Tolerance: A Survey

Visinsky, Monica L.; Cavallaro, Joseph R.; Walker, Ian D.
Fonte: Elsevier Science Limited Publicador: Elsevier Science Limited
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
66.64%
Fault tolerance is increasingly important for robots, especially those in remote or hazardous environments. Robots need the ability to effectively detect and tolerate internal failures in order to continue performing their tasks without the need for immediate human intervention. Recently, there has been a surge of interest in robot fault tolerance, and the subject has been investigated from a number of points of view. Ongoing research performs off-line and on-line failure analyses of robotic systems, develops fault-tolerant control environments, and derives fault detection and error recovery techniques using hardware, kinematic, or functional redundancy. This paper presents a summary of the current, limited, state-of-the-art in fault-tolerant robotics and offers some future possibilities for the field.

A Dynamic Fault Tolerance Framework for Remote Robots

Visinsky, Monica L.; Cavallaro, Joseph R.; Walker, Ian D.
Fonte: IEEE Publicador: IEEE
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
66.75%
Fault tolerance is increasingly important for robots, especially those in remote or hazardous environments. Robots need the ability to effectively detect and tolerate internal failures in order to continue performing their tasks without the need for immediate human intervention. This paper presents a layered fault tolerance framework containing new fault detection and tolerance schemes. The framework is divided into servo, interface, and supervisor layers. The servo layer is the continuous robot system and its normal controller. The interface layer monitors the servo layer for sensor or motor failures using analytical redundancy based fault detection tests. A newly developed algorithm generates the dynamic thresholds necessary to adapt the detection tests to the modeling inaccuracies present in robotic control. Depending on the initial conditions, the interface layer can provide some sensor fault tolerance automatically without direction from the supervisor. If the interface runs out of alternatives, the discrete event supervisor searches for remaining tolerance options and initiates the appropriate action based on the current robot structure indicated by the fault tree database. The layers form a hierarchy of fault tolerance which provide different levels of detection and tolerance capabilities for structurally diverse robots.

Coordinated Checkpoint/Restart Process Fault Tolerance for MPI Applications on HPC Systems

Hursey, Joshua James
Fonte: [Bloomington, Ind.] : Indiana University Publicador: [Bloomington, Ind.] : Indiana University
Tipo: Doctoral Dissertation
Português
Relevância na Pesquisa
66.67%
Thesis (Ph.D.) - Indiana University, Computer Sciences, 2010; Scientists use advanced computing techniques to assist in answering the complex questions at the forefront of discovery. The High Performance Computing (HPC) scientific applications created by these scientists are running longer and scaling to larger systems. These applications must be able to tolerate the inevitable failure of a subset of processes (process failures) that occur as a result of pushing the reliability boundaries of HPC systems. HPC system reliability is emerging as a problem in future exascale systems where the time to failure is measured in minutes or hours instead of days or months. Resilient applications (i.e., applications that can continue to run despite process failures) depend on resilient communication and runtime environments to sustain the application across process failures. Unfortunately, these environments are uncommon and not typically present on HPC systems. In order to preserve performance, scalability, and scientific accuracy, a resilient application may choose the invasiveness of the recovery solution, from completely transparent to completely application-directed. Therefore, resilient communication and runtime environments must provide customizable fault recovery mechanisms. Resilient applications often use rollback recovery techniques for fault tolerance: particularly popular are checkpoint/restart (C/R) techniques. HPC applications commonly use the Message Passing Interface (MPI) standard for communication. This thesis identifies a complete set of capabilities that compose to form a coordinated C/R infrastructure for MPI applications running on HPC systems. These capabilities...

Expert System Framework for Fault Detection and Fault Tolerance in Robotics

Visinsky, Monica L.; Cavallaro, Joseph R.; Walker, Ian D.
Fonte: Elsevier Science Ltd Publicador: Elsevier Science Ltd
Tipo: Journal article; Text; Text
Português
Relevância na Pesquisa
66.75%
Fault tolerance is of increasing importance for modern robots. The ability to detect and tolerate failures enables robots to effectively cope with internal failures and continue performing assigned tasks without the need for immediate human intervention. To monitor fault tolerance actions performed by lower level routines and to provide higher level information about a robot's recovery capabilities, we present an expert system and critic which together form a novel and intelligent fault tolerance framework integrating fault detection and tolerance routines with dynamic fault tree analysis. A higher level, operating system inspired critic layer provides a buffer between robot fault tolerant operations and the user. The expert system gives the framework the modularity and flexibility to quickly convert between a variety of robot structures and tasks. It also provides a standard interface to the fault detection and tolerance software and a more intelligent means of monitoring the progress of failure and recovery throughout the robot system. The expert system further allows for prioritization of tasks so that the components essential to fault detection and tolerance within a system and detail the interconnection between failures in the system. The trees are also used quantitatively to provide a dynamic estimate of the probability of failure of the entire system or various subsystems.; National Science Foundation; Sandia National Laboratory; Mitre Corporation Graduate Fellowship; NSF Graduate Fellowship

Motf : meta-objetos para tolerância a falhas; Moft-metaobjects for fault-tolerance

Lisboa, Maria Lucia Blanck
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Tese de Doutorado Formato: application/pdf
Português
Relevância na Pesquisa
66.8%
As técnicas de programação e os mecanismos de linguagens de programação destinados ao desenvolvimento de aplicações de alta confiabilidade são agrupadas sob a denominação de tolerância a falhas em software. A área de tolerância a falhas abrange uma serie de técnicas com funcionalidades e aplicabilidade bem definidas, permitindo que seja considerada um domínio próprio - o domínio de tolerância a falhas. O conteúdo de informação desse domínio não é auto-suficiente, uma vez que atua sobre outros domínios. Seu objetivo é garantir as funcionalidades das aplicações desenvolvidas em outros domínios. Ao conjugar o domínio de tolerância a falhas a um outro domínio, ou seja, ao domínio de uma aplicação, o primeiro passa a se responsável pelos requisitos não-funcionais da aplicação. Os requisitos não funcionais de uma aplicação, a exemplo de confiabilidade e segurança, são cruciais em muitas aplicações e exigem métodos e conhecimentos que são distintos do domínio da aplicação. O modelo de orientação a objetos incentiva o desenvolvimento de aplicações através da composição de objetos, cada qual com a sua estrutura e comportamento específicos. Cada particular composição de objetos forma um conjunto que deve observar um comportamento que atenda aos requisitos da aplicação...

Aspect-oriented fault tolerance for real-time embedded systems

Afonso, Francisco; Silva, Carlos A.; Brito, Nuno; Montenegro, Sérgio; Tavares, Adriano
Fonte: Association for Computing Machinery (ACM) Publicador: Association for Computing Machinery (ACM)
Tipo: Conferência ou Objeto de Conferência
Publicado em //2008 Português
Relevância na Pesquisa
66.72%
Real-time embedded systems for safety-critical applications have to introduce fault tolerance mechanisms in order to cope with hardware and software errors. Fault tolerance is usually applied by means of redundancy and diversity. Redundant hardware implies the establishment of a distributed system executing a set of fault tolerance strategies by software, and may also employ some form of diversity, by using different variants or versions for the same processing. This paper describes our approach to introduce fault tolerance in distributed embedded systems applications, using aspect-oriented programming (AOP). A real-time operating system sup-porting middleware thread communication was integrated to a fault tolerant framework. The introduction of fault tolerance in the system is performed by AOP at the application thread level. The advantages of this approach include higher modularization, less efforts for legacy systems evolution and better configurability for testing and product line development. This work has been tested and evaluated successfully in several fault tolerant configurations and presented no significant performance or memory footprint costs.; Fundação para a Ciência e a Tecnologia (FCT)

Application-level fault tolerance in real-time embedded systems

Afonso, Francisco; Silva, Carlos A.; Tavares, Adriano; Montenegro, Sérgio
Fonte: IEEE Publicador: IEEE
Tipo: Conferência ou Objeto de Conferência
Publicado em /06/2008 Português
Relevância na Pesquisa
66.65%
Critical real-time embedded systems need to make use of fault tolerance techniques to cope with operation time errors, either in hardware or software. Fault tolerance is usually applied by means of redundancy and diversity. Redundant hardware implies the establishment of a distributed system executing a set of fault tolerance strategies by software, and may also employ some form of diversity, by using different variants or versions for the same processing. This work proposes and evaluates a fault tolerance framework for supporting the development of dependable applications. This framework is build upon basic operating system services and middleware communications and brings flexible and transparent support for application threads. A case study involving radar filtering is described and the framework advantages and drawbacks are discussed.; Fundação para a Ciência e a Tecnologia (FCT)

Technology Impacts of CMOS Scaling on Microprocessor Core Design for Hard-Fault Tolerance in Single-Core Applications and Optimized Throughput in Throughput-Oriented Chip Multiprocessors

Bower, Fred
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação Formato: 2113722 bytes; application/pdf
Publicado em //2010 Português
Relevância na Pesquisa
66.58%

The continued march of technological progress, epitomized by Moore’s Law provides the microarchitect with increasing numbers of transistors to employ as we continue to shrink feature geometries. Physical limitations impose new constraints upon designers in the areas of overall power and localized power density. Techniques to scale threshold and supply voltages to lower values in order to reduce power consumption of the part have also run into physical limitations, exacerbating power and cooling problems in deep sub-micron CMOS process generations. Smaller device geometries are also subject to increased sensitivity to common failure modes as well as manufacturing process variability.

In the face of these added challenges, we observe a shift in the focus of the industry, away from building ever–larger single–core chips, whose focus is on reducing single–threaded latency toward a design approach that employs multiple cores on a single chip to improve throughput. While the early multicore era utilized the existing single–core designs of the previous generation in small numbers, subsequent generations have introduced cores tailored to multicore use. These cores seek to achieve power-efficient throughput and have led to a new emphasis on throughput-oriented computing...

Feasibility assessment of a Kalman filter approach to fault detection and fault-tolerance in a highly unstable system: The RIT heart pump

Gillespie, Erin
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
66.74%
The purpose of this project is to assess the feasibility of a Kalman Filter approach for fault detection in a highly unstable system, specifically the heart pump currently under development at RIT. Simulations and experimental work were completed to determine the effects of possible position sensor fault conditions on the system; that information was then used in conjunction with a pair of Kalman filters to create a method of detecting faults and providing fault-tolerant operation. The heart pump system was modeled using Simulink and then the fault diagnosis and tolerance system was added to the model and tested via simulation in SIMULINK TM. The simulations showed the filters were able to calculate and remove bias caused by any type of position sensor error, provided the estimated plant model is nearly identical to the actual plant model. Sensitivity analysis showed that the fault detection/fault-tolerance method is extremely sensitive to discrepancies between the estimated plant model and actual pump behavior. Because of this, it is considered unfeasible for implementation on a real system. Experimental results confirmed these findings, demonstrating the drawbacks of model-based fault detection and tolerance methods.