Analysis of dark Websites is important for developing effective combating strategies against terrorism or extremists when more and more scattered terrorist cells use the ubiquity of the Internet to form communities in virtual space with fairly low costs. Terrorists or extremists anonymously set up various Web sites embedded in the public Internet, exchanging ideology, spreading propaganda, and recruiting new members. In this paper, we propose a framework to discover latent topics via analyzing contents of dark Websites. The content and data from dark Websites are gathered and extracted by crawlers and exported to documents. Latent Dirichlet allocation (LDA) algorithm is used to analyze the extracted documents so as to discover latent topics from web sites of terrorists or extremists. In contrast to the traditional information retrieval (IR) schemes, LDA-based analysis assigns a probability to a document and captures exchangeability of both words and documents. Our work helps to gain insights into the structure and communities of terrorists and extremists.

Information systems that use the mediation architecture are well suited to accessing heterogeneous data in a distributed environment. These mediation systems utilize a central security mediator that is primarily concerned with securing the internal structure of the mediation system. The current problem with this approach is that clients are unable to have authority and administer the security of their data during the collaboration with the mediation system. This creates a black box scenario from the perspective of the client towards the mediation system, which can have great consequences in transactions that deal with sensitive data within an untrusted environment. In this paper, we present a solution in the form of a decentralized mediator that provides all parties involved in a transaction within the mediation system autonomy over their security that is security model independent and dynamic at runtime. Our approach allows the client to manage the access to data during a transaction with the mediation system.

Multicast has been used as a one-to-many approach to deliver information; it is based on the idea that if one package of data should be transmitted to several recipients, the information should be sent by the origin just one time. In this paper, we propose the use of overlay multicast to distribute content and to make distribution more efficient, we combine it with a P2P approach. Our research includes a token-based algorithm to construct multicast trees based on information provided by a tracker and a comparison with current Bit-Torrent implementations. We focus on environments such as large-scale enterprise networks.

Most access control models have formal access control rules to govern the authorization of a request from a principal. In pervasive and collaborative environments, the behaviors of a principal are uncertain due to partial information. Moreover, the attributes of a principal, requested objects, and contexts of a request are mutable during the collaboration. A variety of such uncertainty and mutability pose challenges when resources sharing must happen in the collaborative environment. In order to address the above challenges, we propose a framework to integrate trust management into a usage control model in order to support decision making in an ever-changing collaborative environment. First, a trust value of a principal is evaluated based on both observed behaviors and peer recommendations. Second, the usage-based access control rules are checked to make decisions on resource exchanges. Our framework handles uncertainty and mutability by dynamically disenrolling untrusted principals and revoking granted on-going access if access control rules are no longer met. We have applied our trust-based usage control framework to an application of file sharing.

The number of computers and high-speed networks connected to the Internet in large-scale organizations has grown in the last two decades. As a consequence, a large number of software applications must be installed and the quantity of data needed for their operation is considerable. This has a high price for IT departments: distribute this content efficiently. We claim that content distribution using P2P file sharing systems can be used to accomplish this; we propose a solution that works even in environments that use NAT and utilizes WAN links efficiently.

A mediation system is designed to support interoperability from distributed, heterogeneous data sources. Research on data integration has provided a set of rich and well-understood schema mediation languages to define either the mediation schema or the contents of data sources. However, the mediation system is a highly dependable complex system, but little work is dedicated to assuring system behavior correctness. Due to the huge program size and complexity of system, it is not possible to formally verify the system properties at the source code level. So the mediation system requires rigorous modeling and analysis techniques to assure the system correctness and properties at the design level. This paper defines and analyzes mediation systems by the software architecture model (SAM), a formal systematic software architecture specification and analysis methodology that is able to define and analyze different system aspects using different formalisms. In this paper, the behaviors of mediation systems are captured by Petri net and the architecture properties are specified and analyzed by temporal logic.

We present a conceptual mediation framework that features three layers of mediators: presence, integration, and homogenization layers that work together in a peer-to-peer (p2p) manner to facilitate the delivery of multimedia data. On arrival of each request for data from a client, a global-mediator is elected from a group of integration layer mediators to service that request. Using distributed hash table (DHT), the global-mediator dispatches the request to other integrator mediators to track down the data sources. Upon receipt of the results, from the source(s), the global-mediator presents the data to the client via a presence-mediator. The presence-mediator may need to reformat the data to suit the execution context of the client. This mediation process is context-aware, adaptive and dynamically structured. Quality of service (QoS) factors are taken into consideration in the retrieval and presentation of data.

The object-oriented programming language Java is an ideal companion to an object-oriented database system. This paper describes our approach to provide an almost seamless application programmer interface that allows Java programs to exchange objects with a database. Unlike other approaches that add persistence capabilities to Java, our approach does not change the Java language nor does it require changes to the Java Virtual Machine. We use reflection, i.e. self-inspection and change of a running program, to map Java classes to database classes, and to enable persistence. The result is a very flexible and efficient style of Java database access.

The object-oriented programming language Java is an ideal companion to an object-oriented database system. This paper describes our approach to provide a seamless application programmer interface. It is based on a modular architecture with components for database engines, a communications protocol and a JAVA API facilitator. The open architecture is flexible, scalable and distributed in nature.

KAPSEL is a new object-oriented programming language to encourage the building of reusable software components. The components, i.e. classes, establish clear boundaries between their implementation detail and their outside-visible specification. The underlying software concept employed is that of encapsulation: the close integration and protection of information and its functionality. The paper explores the basic idea of encapsulation in object-oriented methodology: as it applies to objects, classes and class hierarchies, and introduces the programming language-KAPSEL-which facilitates the specification of reusable object-oriented software components.

Object-oriented user interface technology increases the productivity of interface designers and programmers. However, there are some shortcomings to the object-oriented approach. An approach that is based on the concept of separating the presentation from the application data is presented. While in object-oriented user interfaces presentation and application data communicate via a protocol of procedure cells, in this approach the relationships are described declaratively with structured sets of maintained constraints. An overall architecture based on constraints that encompasses all aspects of a user interface is described. The procedural behavior of a user interface is achieved through constraint satisfaction.>

This paper describes an approach to object-oriented interface design that goes beyond mere object decomposition. In our user interface management system we use logic and filters to declaratively specify and control a space of ways that objects may be composed to create interfaces. A filter is a package of constraints and associated typed objects that express the relationship of data and representation objects.Conceptually our system is completely based on constraints. Filters provide the high bandwidth constraints to maintain the components of the direct-manipulation interface while the logic forms the low bandwidth constraints to combine and provide communication between these components. The use of Horn-clause logic to compose separate interface objects facilitates both the distribution of computation onto multiple processors and the generation of multiple views of data. Intelligent backtracking implemented in the logic allows for user- and system-initiated undo operations to correct errors and/or try alternative approaches to a problem. We illustrate the power and flexibility of this approach by describing a floor layout and design system.