36436312
Simplifying CORBA Security Service to Support Service Level Access Control
The CORBA Security Service provides a domain based access control model in which interfaces are grouped in domains and a single security policy applies to all the interfaces in the domain. CORBA Security Service does not directly support object and method level access control rules. Grouping interfaces in domains helps in reducing access control rules in a large system with a large number of objects. In an environment where services are provided using methods and similar services are grouped as the methods of an interface, providing service and interface level access control is desirable.
5053302
Componentxchange: An E-Exchange for Software Components
A key challenge in Component-Based Software Engineering (CBSE) is finding appropriate software components for reuse. A component broker that allows component vendors to make available their modules, and also allows component integrators to search and select components matching their requirements will help solve this problem. In this paper, we describe an E-Exchange for buying and selling of software components over the World Wide Web. The ComponentXchange uses an XML based specification language for components, which is a semi-formal specification language that can describe a rich and an extensible set of component properties including functional properties, non-functional attributes and licensing aspects. ComponentXchange supports two models of component trading. A component can be used either by downloading it and integrating it into the client application or by accessing it remotely over the network. It has a licensing server that enforces the licensing terms and conditions. ComponentXchange can be easily extended to support different payment models like pay-per-use, pay-per-user, etc.
2732754
A server side caching scheme for CORBA
We propose a caching scheme for saving the results of invocations of read methods at server side. Server side caching helps in reducing load on frequently accessed servers when computing the result is relatively costly. Our model provides strong consistency by using a dependency graph that specifies dependence information among method invocations of an object. We have implemented this scheme as a service in CORBA.
7291217
Merging workflows: A new perspective on connecting business processes
This paper describes the concept of workflow merge and methods for merging business processes. We grouped merges in four categories according to the type of merge: sequential, parallel, conditional, and iterative, and describe the corresponding algorithms for performing these operations. We give results that allow us to determine whether a merge operation is sound. It is shown that to avoid invalid merges, one should choose merge points between which a sub-workflow, called a merge region, is well structured. These findings can provide useful guidance for future workflow merge research. We also raise issues of more complex merge problems, such as merge conflicts, semantic ambiguities and workflow splits.
206560175
A constant-factor approximation algorithm for the multicommodity rent-or-buy problem
We present the first constant factor approximation algorithm for network design with multiple commodities and economies of scale. We consider the rent-or-buy problem, a type of multicommodity buy-at-bulk network design in which there are two ways to install capacity on any given edge. Capacity can be rented, with cost incurred on a per-unit of capacity basis, or bought, which allows unlimited use after payment of a large fixed cost. Given a graph and a set of source-sink pairs, we seek a minimum-cost way of installing sufficient capacity on edges so that a prescribed amount of flow can be sent simultaneously from each source to the corresponding sink. Recent work on buy-at-bulk network design has concentrated on the special case where all sinks are identical; existing constant factor approximation algorithms for this special case make crucial use of the assumption that all commodities ship flow to the same sink vertex and do not obviously extend to the multicommodity rent-or-buy problem. Prior to our work, the best heuristics for the multicommodity rent-or-buy problem achieved only logarithmic performance guarantees and relied on the machinery of relaxed metrical task systems or of metric embeddings. By contrast, we solve the network design problem directly via a novel primal-dual algorithm.
433794
A Framework for Document-Driven Workflow Systems
We propose and demonstrate the feasibility of a framework for document-driven workflow systems that requires no explicit control flow and the execution of the process is driven by input documents. The framework can assist workflow designers to discover the data dependencies between tasks in a process and achieve more efficient control flow design. The framework also provides an architecture to separate the workflow system from application data and facilitate inter-organizational processes. Document-driven workflow systems are more flexible than traditional control flow processes, easier to verify and work better for ad hoc workflows. We also implemented a prototype workflow system using the framework entirely in a RDBMS using Transact-SQL in Microsoft SQL Server 2000. A detailed comparison with control driven workflows has also been done.
45847616
EROICA: A Rule-Based Approach to Organizational Policy Management in Workflow Systems
Conventional workflow management systems have been criticized for being too rigid in dealing with changes in organizational policies, in particular for the lack of flexible mechanisms for handling complex role resolution. In this paper we describe a rule-based approach (EROICA) for managing organizational policies in workflow systems. Our approach extends the well-known ECA (event-condition-action) approach used in database systems by elevating roles, objects and time intervals to first class citizens, hence the term EROICA (event-role-object-interval-condition-action). In this paper, we focus on the development of a flexible role resolution mechanism that operates under various business constraints specified with EROICA rules. We further discuss the issues of architecture and implementation and demonstrate that the EROICA framework is promising in making next generation of workflow systems more powerful and flexible.
1890977
W-RBAC - A Workflow Security Model Incorporating Controlled Overriding of Constraints
This paper presents a pair of role-based access control models for workflow systems, collectively known as the W-RBAC models. The first of these models, W0-RBAC is based on a framework that couples a powerful RBAC-based permission service and a workflow component with clear separation of concerns for ease of administration of authorizations. The permission service is the focus of the work, providing an expressive logic-based language for the selection of users authorized to perform workflow tasks, with preference ranking. W1-RBAC extends the basic model by incorporating exception handling capabilities through controlled and systematic overriding of constraints.