8072493
Authorization and Access Control in Adaptive Workflows
In recent years we have witnessed the development of adaptive workflow management systems. These systems offer an extended set of features to support both ad-hoc and evolutionary changes, while ensuring correctness of process definition and their running instances. Ad-hoc and evolutionary changes impose new access control requirements, which have been neglected by adaptive workflow research and are not met by existing models for traditional workflow management systems (WfMSs). In this paper, we extend the role-based access control model for adaptive workflows. This extension is done by defining authorizations for adaptive WfMSs and adaptive authorizations.
38014527
A Quality Design Solution for Object Synchronization
This paper presents a quality design solution, the Customizable Object Synchronization pattern, for object synchronization which decouples object synchronization from object concurrency and object functionality (sequential part). The solution described by this pattern provides encapsulation, extensibility, modularity and reuse of synchronization policies.
16566221
Naming: design pattern and framework
Naming is an important, but frequently overlooked, aspect of software systems. Naming is usually combined with other issues, e.g. distributed communication technology. The paper treats naming in isolation. It presents a naming design pattern which abstracts several naming policies and an object-oriented framework that can be customized to support naming policies. An applications designer can choose the correct naming properties (relative, absolute, universal identifiers, etc.) to refer to specific objects.
9321144
Using separation and composition of concerns to build multiuser virtual environments
Developing multiuser virtual environments (MUVE) is a very complex task since it involves several engineering domain aspects such as virtual reality, cooperative work and distributed systems. Furthermore, existing technologies like graphics capabilities, processing power and network bandwidth, are permanently evolving. For MUVE systems to be successfully developed, they must not only deal with all the different aspects that are inherent to these systems but also have the ability to deal with the continuous technology and requirements evolution. To cope with these problems, a software engineering separation of concerns approach is proposed. Concerns are identified for each of the different aspects of MUVEs. To obtain the necessary flexibility, each one of the concerns should abstract its possible variations in order to support the future system evolution. Moreover it is shown how concerns composition has the necessary expressive power to build multiuser virtual environments.
203567
Separating replication from distributed communication: problems and solutions
Replication and distributed communication are usually tightly coupled. This code tangling forbids their independent reuse and adaptation. In this position paper, the problems resulting from coupling replication with distributed communication are discussed. In addition, a solution based on separation of concerns is proposed. The abstractions for each concern are presented, as well as their composition.
35073381
Service Logic Deployment and Distribution Configuration
The success of service providers in the competitive communications market of the future will be determined by the efficiency with which services are developed, and the quality levels at which services are provided. A service creation environment (SCE) should provide the service developer with solutions to these problems. In this paper we present two essential facilities that should be provided by an advanced SCE: a tool for the optimisation of the service logic deployment scheme and a distribution configuration language supporting the deployment and configuration of component-based distributed applications.
15351818
Representing Web Data as Complex Objects
The popularization of the Web has made a huge volume of data available for a large audience. In a large number of Web sites, such as bookstores, electronic catalogs, travel agencies, etc., the pages constitute documents which are composed of pieces of data whose overall structure can be easily recognized. Such pages are called data-rich and can be seen as collections of complex objects. In this paper, we show how such objects can be represented by nested tables, which are simple, intuitive, and quite convenient for expressing their implicit structure. The assumption is that, for most sites of interest, only few examples are required to reveal the structure of the objects. To corroborate our assumption, we describe a data extraction tool that adopts this approach and present results of some experiments carried out with this tool.
7623756
Knowledge Management Systems Development: A Roadmap
This paper approaches the Knowledge Management Systems study, focusing not only in the establishment of essential development activities, but also in techniques, technologies, and tools for their support. Despite of the wide range of existing proposals for the development of this type of systems, none of them has achieved a level detailed enough to allow a direct application. This study is intended to be a palliative for the above-mentioned lack of detail by means of a development guide for Knowledge Management Systems. In this way, the proposed solution offers a clear definition concerning what has to be done and which type of mechanisms should be used for its development.
10782860
OrgSwarm - A Particle Swarm Model of Organizational Adaptation
This study extends the particle swarm metaphor to include the domain of organizational adaptation. A simulation model, OrgSwarm, is constructed in order to examine the impact of strategic inertia on the adaptive potential of a population of organizations. The key finding is that a degree of strategic inertia, in the presence of an election mechanism, can assist rather than hamper adaption of the population.
12195414
Evolving Controllers for Autonomous Agents Using Genetically Programmed Networks
This article presents a new approach to the evolution of controllers for autonomous agents. We propose the evolution of a connectionist structure where each node has an associated program, evolved using genetic programming. We call this structure a Genetically Programmed Network and use it to successfully evolve control systems with very different architectures, by making small restrictions to the evolutionary process. Experimental results of applying this method to evolve neural networks, distributed programs and rule-based systems capable of solving a common benchmark problem, the Ant Problem, are presented. Comparison with other known genetic programming based approaches, shows that our method requires less effort to find a solution.
14702137
A Multi-Neighbor-Joining Approach for Phylogenetic Tree Reconstruction and Visualization
The computationally challenging problem of reconstructing the phylogeny of a set of contemporary data, such as DNA sequences or morphological attributes, was treated by an extended version of the neighbor-joining (NJ) algorithm. The original NJ algorithm provides a single-tree topology, after a cascade of greedy pairing decisions that tries to simultaneously optimize the minimum evolution and the least squares criteria. Given that some sub-trees are more stable than others, and that the minimum evolution tree may not be achieved by the original NJ algorithm, we propose a multi-neighbor-joining (MNJ) algorithm capable of performing multiple pairing decisions at each level of the tree reconstruction, keeping various partial solutions along the recursive execution of the NJ algorithm. The main advantages of the new reconstruction procedure are: 1) as is the case for the original NJ algorithm, the MNJ algorithm is still a low-cost reconstruction method; 2) a further investigation of the alternative topologies may reveal stable and unstable sub-trees; 3) the chance of achieving the minimum evolution tree is greater; 4) tree topologies with very similar performances will be simultaneously presented at the output. When there are multiple unrooted tree topologies to be compared, a visualization tool is also proposed, using a radial layout to uniformly distribute the branches with the help of well-known metaheuristics used in computer science.