17691685
WFMS-based Data Integration for e-Learning
As more and more organisations and institutions are moving towards the e-learning strategy, more and more disparate data are distributed by different e-learning systems. How to effectively use this vast amount of distributed data becomes a big challenge. This paper addresses this challenge and works out a new mechanism to implement data integration for e-learning. A workflow management system based (WFMS-based) data integration model is contributed to the e-learning
18875168
Towards Autonomous Service Level Agreement Negotiation for Adaptive Service Composition
This paper reports innovative research aiming at supporting autonomous establishment and maintenance of service level agreements in order to guarantee end-to-end quality of service requirements for service composition provision. In this research, a set of interrelated service level agreements is established and maintained for a service composition, through autonomous agent negotiation. To enable this, an innovative framework is proposed in which agents on behalf of the service requestor and the service providers can negotiate service level agreements in a coordinated way. This framework also enables adaptive service level agreement re-negotiation in the dynamic and ever-changing service environment
15557099
Enacting Business Processes in a Decentralised Environment with p2p-Based Workflow Support
Traditionally, workflow adopts a centralised client/server architecture to enact processes, which has exhibited many weaknesses. This paper combines concepts from workflow technology and peer-to-peer computing and presents an innovative approach to support decentralised process enactment. With this approach, both process instantiation and instance execution are carried out in a genuinely decentralised fashion, which reflects applications’ increasingly distributed nature better. In general, the process instance is created with relevant participants creating various task instances at different locations. In addition, instance execution is coordinated through direct communication among relevant workflow participants.
132181
A note on proactive password checking
Nowadays, proactive password checking algorithms are based on the philosophy of the dictionary attack, and they often fail to prevent some weak passwords with low entropy. In this paper, a new approach is proposed to deal with this new class of weak passwords by (roughly) measuring entropy. A simple example is given to exploit effective patterns to prevent low-entropy passwords as the first step of entropy-based proactive password checking.
9935355
Security design in online games
The emergence of online games has fundamentally changed security requirements for computer games, which previously were largely concerned with copy protection. We examine how new security requirements impact the design of online games by using online bridge, a simple client-server game, as our case study. We argue that security is emerging as an inherent design issue for online games, after graphics and artificial intelligence, which have become important issues of the design of most games for decades. The most important new security concern in online game design is fairness enforcement, and most security mechanisms all contribute to a single objective, namely, making the play fair for each user.
4689080
Local Discontinuous Galerkin Methods for Partial Differential Equations with Higher Order Derivatives
In this paper we review the existing and develop new local discontinuous Galerkin methods for solving time dependent partial differential equations with higher order derivatives in one and multiple space dimensions. We review local discontinuous Galerkin methods for convection diffusion equations involving second derivatives and for KdV type equations involving third derivatives. We then develop new local discontinuous Galerkin methods for the time dependent bi-harmonic type equations involving fourth derivatives, and partial differential equations involving fifth derivatives. For these new methods we present correct interface numerical fluxes and prove L2 stability for general nonlinear problems. Preliminary numerical examples are shown to illustrate these methods. Finally, we present new results on a post-processing technique, originally designed for methods with good negative-order error estimates, on the local discontinuous Galerkin methods applied to equations with higher derivatives. Numerical experiments show that this technique works as well for the new higher derivative cases, in effectively doubling the rate of convergence with negligible additional computational cost, for linear as well as some nonlinear problems, with a local uniform mesh.
206485325
Password memorability and security: empirical results
Users rarely choose passwords that are both hard to guess and easy to remember. To determine how to help users choose good passwords, the authors performed a controlled trial of the effects of giving users different kinds of advice. Some of their results challenge the established wisdom.
36905463
Quasi-threshold Graphs
Abstract Quasi-threshold graphs are defined recursively by the following rules: 1. (1) K1 is a quasi-threshold graph, 2. (2) adding a new vertex adjacent to all vertices of a quasi-threshold graph results in a quasi-threshold graph, 3. (3) the disjoint union of two quasi-threshold graphs is a quasi-threshold graph. This paper gives some new equivalent definitions of a quasi-threshold graph. From them, linear time recognition algorithms follow. We also give linear time algorithms for the edge domination problem and the bandwidth problem in this class of graphs.