4907231
Temporal Dependency for Dynamic Verification of Fixed-Date Constraints in Grid Workflow Systems
Grid workflow systems aim to support large-scale complex e-science and e-business processes. Due to the complexity of these kinds of processes, to control the execution of them in terms of time in the grid workflow execution environments, multiple fixed-date temporal constraints often need to be set simultaneously. Hence the dependency problem between them must be considered and emphasised, which affects the verification effectiveness and efficiency of the fixed-date temporal constraints. However, current relevant workflow verification works do not take into consideration this dependency. Therefore, in this paper, we explore it in depth and analyse its impact on the verification of the fixed-date temporal constraints. Furthermore, based on the temporal dependency, we develop some new temporal verification methods and algorithms. The comparison and evaluation show that these new methods and algorithms make the verification more effective and efficient. All these analyses, new methods and algorithms further strengthen the grid workflow time management.
4924842
Assigning Local Fixed-time Constraints in Grid Workflow Systems
Many complex grid workflow processes often have only one global fixed-time constraint at the last activity. Since grid workflow execution normally lasts a long time, local control is very important to ensure the overall temporal correctness. With only one global fixed-time constraint, we cannot control grid workflow execution locally in terms of time. As a result, for any temporal violations, we must handle them globally with the consideration of all activities. This would impact the overall cost-effectiveness of grid workflow execution. Therefore, in this paper, we investigate how to assign local fixed-time constraints within the global one so that we can control grid workflow execution locally. Corresponding assigning and verification methods are developed. With local fixed-time constraints, we can achieve better cost-effectiveness
3428244
An Organisational Perspective on Collaborative Business Processes
Business collaboration is about coordinating the flow of information among organisations and linking their business processes. It brings great challenge to keep participating organisations as autonomous entities in integrating business processes of these organisations seamlessly. To address this issue, we develop a new perspective on business collaborations with a novel concept called relative workflow, which defines what a participating organisation can perceive in collaboration. By incorporating a visibility control mechanism, relative workflows allow each organisation to define its own collaboration structure and behaviours. In this paper, we present a formal definition of relative workflows and related algorithms for generating relative workflows, along with a discussion on how to perform tracking over relative workflows.
1701823
Dynamic checking of temporal constraints for concurrent workflows
At present, workflow management systems have not sufficiently dealt with the issues of time, involving time modelling at build-time and time management at run-time. They are lack of the ability to support the checking of temporal constraints at run-time. Although some approaches have been devised to tackle this problem, they are limited to a single workflow and use only static techniques to verify temporal constraints. In reality, there are multiple workflows executing concurrently in a workflow management system. There may well exist resource constraints between these concurrent workflows, which affect significantly the verification of temporal constraints at run-time. This paper proposes a novel approach for dynamic verification of temporal constraints for concurrent workflows. We first investigate resource constraints in workflow management systems, and then define concurrent workflow executions. Based on these definitions, we propose a verification method by analysing the temporal relationship and resource constraints between activities among concurrent workflows.
4928164
A service workflow management framework based on peer-to-peer and agent technologies
Service workflow management which consolidates multiple services to achieve business goals has become a critical issue in service-oriented computing. Due to the unique feature of service workflows such as full distribution and high dynamicity, the contemporary workflow technology has exhibited inefficiency, vulnerability, inflexibility and lack of adaptability. Based upon the authors' previous work on peer-to-peer based workflow management and seamless integration of agents and Web services, this paper innovatively presents SwinDeW-A which is a decentralised service workflow management framework based on peer-to-peer and agent technologies. Based on this framework, this paper also discusses how autonomous service level agreement negotiation, decentralised process enactment, and autonomous process adaptation can be achieved. The proposed approach takes advantages of the peer-to-peer computing technology and the agent technology to provide more efficient, reliable, flexible and adaptive service workflow management.
14447070
Achieving convergence, causality preservation, and intention preservation in real-time cooperative editing systems
Real-time cooperative editing systems allow multiple users to view and edit the same text/graphic/image/multimedia document at the same time for multiple sites connected by communication networks. Consistency maintenance is one of the most significant challenges in designing and implementing real-time cooperative editing systems. In this article, a consistency model, with properties of convergence, causality preservation, and intention preservation, is proposed as a framework for consistency maintenance in real-time cooperative editing systems. Moreover, an integrated set of schemes and algorithms, which support the proposed consistency model, are devised and discussed in detail. In particular, we have contributed (1) a novel generic operation transformation control algorithm for achieving intention preservation in combination with schemes for achieving convergence and causality preservation and (2) a pair of reversible inclusion and exclusion transformation algorithms for stringwise operations for text editing. An Internet-based prototype system has been built to test the feasibility of the proposed schemes and algorithms
309943
Optimizing cost and performance for multihoming
Multihoming is often used by large enterprises and stub ISPs to connect to the Internet. In this paper, we design a series of novel smart routing algorithms to optimize cost and performance for multihomed users. We evaluate our algorithms through both analysis and extensive simulations based on realistic charging models, traffic demands, performance data, and network topologies. Our results suggest that these algorithms are very effective in minimizing cost and at the same time improving performance. We further examine the equilibrium performance of smart routing in a global setting and show that a smart routing user can improve its performance without adversely affecting other users.
58339956
IPsec/VPN security policy correctness and assurance
With IPsec/VPN policies being widely deployed, how to correctly specify and configure them is critical in enforcing security requirements, especially among different administrative domains across the Internet. Under current practice, IPsec/VPN policies are specified individually by system administrators from different organizations without any formal coordination. This practice implies unintentional errors due to inconsistent IPsec/VPN policies. Furthermore, Internet routing dynamics may possibly interfere with IPsec/VPN policies such that unexpected conflicts occur due to a mismatch between the routing and IPsec/VPN layers. To deal with these problems, we formally define IPsec security requirements, policies, and their correctness criteria. Based on these definitions, we present an inter-domain architecture to automatically generate correct and efficient security policies. Our approach works when we are given a set of security requirements for a single end-to-end traffic flow. We can also deal with changes when new security requirements are added. Finally, we present simulation results which evaluate the performance of our solutions.
13584016
kNN, Rocchio and Metrics for Information Filtering at TREC-10
We compared a multi-class k-nearest neighbor (kNN) approach and a standard Rocchio method in the filtering tasks of TREC-10. Empirically, we found kNN more effective in batch filtering, and Rocchio better in adaptive filtering. For threshold adjustment based on relevance feedback, we developed a new strategy that updates a local regression over time based on a sliding window over positive examples and a sliding window over negative examples in the history. Applying this strategy to Rocchio and comparing its results to those by the same method with a fixed threshold, the recall was improved by 37-39% while the precision was improved by as much as 9%. Motivated by the extremely low performance of all systems on the T10S metric, we also analyzed this metric, and found that it favors more frequently occurring categories over rare ones and is somewhat inconsistent with its most straightforward interpretation. We propose a change to this metric which fixes these problems and brings it closer to the C trk metric used to evaluate the TDT tracking task.
5091874
Integrating Web Services into Ontology-Based Web Portal
With the explosive emerged Web services, the Web becomes a world of information and applications. So portals whose goal is presenting a structured view onto the Web should provide users with a single point access to multiple types of not only information but also services. Recently, many systems have been developed using ontology-driven approaches to automatically generate and manage Web portals. However, all of them lack the integration of Web services. In this paper, we describe SPortS, an OWL-DL(Web Ontology Language-Description Logics) based portal generation system that integrates semantic Web services into generated portals at the presentation level, the data level and the function level. We present the portal generation process, the query decomposition and the service recommendation algorithms through which semantic Web services are integrated tightly into the generated portal.
18309490
Structure Pruning Strategies for Min-Max Modular Network
The min-max modular network has been shown to be an efficient classifier, especially in solving large-scale and complex pattern classification problems. Despite its high modularity and parallelism, it suffers from quadratic complexity in space when a multiple-class problem is decomposed into a number of linearly separable problems. This paper proposes two new pruning methods and an integrated process to reduce the redundancy of the network and optimize the network structure. We show that our methods can prune a lot of redundant modules in comparison with the original structure while maintaining the generalization accuracy.