32,795 research outputs found
Constraint integration and violation handling for BPEL processes
Autonomic, i.e. dynamic and fault-tolerant Web service composition is a requirement resulting from recent developments such as on-demand services. In the context of planning-based service composition, multi-agent planning and dynamic error handling are still unresolved problems. Recently, business rule and constraint management has been looked at for enterprise SOA to add business flexibility. This paper proposes a constraint integration and violation handling technique for dynamic service composition. Higher degrees of reliability and fault-tolerance, but also performance for autonomously composed WS-BPEL processes are the objectives
A diversity-based approach for managing faults in web services
This paper discusses the value-added of diversity to support fault tolerant Web Services operation. Web Services offering the same functionality are gathering into the same virtual space referred to as diversity group. Besides the group additional components are used including: composite manager, group manager, and Web service manager. The first component invokes the diversity groups and either resumes or aborts the overall execution in case of failures. The second component oversees Web services execution and the interactions between them. Finally, the last component monitors a Web service execution and reports either failure or success to the group manager. An architecture and a set of experiments showing the use of diversity to design and deploy fault tolerant Web services is presented in this paper. © 2012 IEEE
A Reliable and Cost-Efficient Auto-Scaling System for Web Applications Using Heterogeneous Spot Instances
Cloud providers sell their idle capacity on markets through an auction-like
mechanism to increase their return on investment. The instances sold in this
way are called spot instances. In spite that spot instances are usually 90%
cheaper than on-demand instances, they can be terminated by provider when their
bidding prices are lower than market prices. Thus, they are largely used to
provision fault-tolerant applications only. In this paper, we explore how to
utilize spot instances to provision web applications, which are usually
considered availability-critical. The idea is to take advantage of differences
in price among various types of spot instances to reach both high availability
and significant cost saving. We first propose a fault-tolerant model for web
applications provisioned by spot instances. Based on that, we devise novel
auto-scaling polices for hourly billed cloud markets. We implemented the
proposed model and policies both on a simulation testbed for repeatable
validation and Amazon EC2. The experiments on the simulation testbed and the
real platform against the benchmarks show that the proposed approach can
greatly reduce resource cost and still achieve satisfactory Quality of Service
(QoS) in terms of response time and availability
A system for access and administration of fault-tolerant web services
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file viewed on (July 14, 2006)Includes bibliographical references.Thesis (M.S.) University of Missouri-Columbia 2005.Dissertations, Academic -- University of Missouri--Columbia -- Computer science.Web Services, a recent development in web technology, enables programs (services) on the World Wide Web (WWW) to communicate with each other. A program (web service) available on the WWW has to be robust to serve the vast number of users on the WWW and should have a high level of availability. This can be achieved by incorporating fault-tolerance in a program by having multiple instances of the same program running on different servers. This thesis presents a system to start, administer and monitor multiple instances of a web service on different servers. The system designed to incorporate fault-tolerance in web services cannot afford to have a single point of failure. Hence, the system itself is designed to be fault-tolerant. This thesis also implements a Web Service Registry that provides a means for the developers to register their web services with the Web Service Registry and thus, make the web services accessible to the world
Reliable Fault Tolerance System for Service Composition in Mobile Ad Hoc Network
A Due to the rapid development of smart processing mobile devices, Mobile applications are exploring the use of web services in MANETs to satisfy the user needs. Complex user needs are satisfied by the service composition where a complex service is created by combining one or more atomic services. Service composition has a significant challenge in MANETs due to its limited bandwidth, constrained energy sources, dynamic node movement and often suffers from node failures. These constraints increase the failure rate of service composition. To overcome these, we propose Reliable Fault Tolerant System for Service Composition in MANETs (RFTSC) which makes use of the checkpointing technique for service composition in MANETs. We propose fault policies for each fault in service composition when the faults occur. Failure of services in the service composition process is recovered locally by making use of Checkpointing system and by using discovered services which satisfies the QoS constraints. A Multi-Service Tree (MST) is proposed to recover failed services with O(1) time complexity. Simulation result shows that the proposed approach is efficient when compared to existing approaches
Automatic Composition of Web Services using Intelligent Agent
Previous works on Web service composition focused on developing algorithms for a specific purpose like efficient composition, efficient composite service or fault tolerant composition. The aim of this research was to develop an agent which will compose efficient Web service and also recover from failure. The performance of the agent was evaluated by simulation. It was found that the proposed composed Web service performs better. It was also able to recover from failure thus reducing failure rate.Computer Science Departmen
Workrs: Fault Tolerant Horizontal Computation Offloading
The broad development and usage of edge devices has highlighted the
importance of creating resilient and computationally advanced environments.
When working with edge devices these desiderata are usually achieved through
replication and offloading. This paper reports on the design and implementation
of Workrs, a fault tolerant service that enables the offloading of jobs from
devices with limited computational power. We propose a solution that allows
users to upload jobs through a web service, which will be executed on edge
nodes within the system. The solution is designed to be fault tolerant and
scalable, with no single point of failure as well as the ability to accommodate
growth, if the service is expanded. The use of Docker checkpointing on the
worker machines ensures that jobs can be resumed in the event of a fault. We
provide a mathematical approach to optimize the number of checkpoints that are
created along a computation, given that we can forecast the time needed to
execute a job. We present experiments that indicate in which scenarios
checkpointing benefits job execution. The results achieved are based on a
working prototype which shows clear benefits of using checkpointing and restore
when the completion jobs' time rises compared with the forecast fault rate. The
code of Workrs is released as open source, and it is available at
\url{https://github.com/orgs/P7-workrs/repositories}. This paper is an extended
version of \cite{edge2023paper}.Comment: extended version of a paper accepted at IEEE Edge 202
Investigation into Mobile Learning Framework in Cloud Computing Platform
Abstract—Cloud computing infrastructure is increasingly
used for distributed applications. Mobile learning
applications deployed in the cloud are a new research
direction. The applications require specific development
approaches for effective and reliable communication. This
paper proposes an interdisciplinary approach for design and
development of mobile applications in the cloud. The
approach includes front service toolkit and backend service
toolkit. The front service toolkit packages data and sends it
to a backend deployed in a cloud computing platform. The
backend service toolkit manages rules and workflow, and
then transmits required results to the front service toolkit.
To further show feasibility of the approach, the paper
introduces a case study and shows its performance
Fault-Tolerant Business Processes
Abstract. Service-oriented computing (SOC) paradigm promotes the
idea of assembling application components into a network of loosely coupled
services. Web services are the most promising SOC-based technology.
A BPEL process definition represents a composite service that encapsulates
some complex business logic including the invocation to other
(external) web services. The complexity of a BPEL process together with
the invocation of external services subject to network and computer failures
requires countermeasures to tolerate this kind of failures. In this
paper we present an overview of FT-BPEL, a fault-tolerant implementation
of BPEL that copes both with failures of the machine running the
BPEL process and network failures in a transparent way, that is, after a
failure the system is able to resume the BPEL process consistently
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