DAVIM: Adaptable Middleware for Sensor Networks

Middleware services facilitate sensor-network application development. DAVIM is adaptable middleware that enables dynamic management of services and isolation between simultaneously running applications.     

NeCoMan: middleware for safe distributed-service adaptation in programmable networks

NeCoMan middleware customizes dynamic adaptation of point-to-point-based network services in programmable networks, taking into account the properties of the network services involved as well as the reconfiguration semantics. This article focuses on safe runtime adaptation of point-to-point-based network services in programmable networks. Many network services such as compression, fragmentation, reliability, and encryption conform to a point-to-point-based distributed-service model. This model represents a pair of tightly coupled components (not necessarily situated on neighboring nodes) that must cooperate to offer a distributed service. To prevent the runtime addition, replacement, or removal of these network services from jeopardizing a programmable network's correct functioning, the network programmer must coordinate the adaptation of the protocol stacks accommodating the service components.     

Symbolic evaluation of dimensionally regularized Feynman diagrams

A modification of the symbolic and algebraic manipulation program REDUCE is reported which allows the treatment of vector and gamma algebra in an arbitrary number of dimensions. The number of dimensions serves as a cut-off for divergences in the Feynman diagrams one has to evaluate in a theory like quantum gravity.     

Compact Representation of Knowledge Bases in Inductive Logic Programming

In many applications of Inductive Logic Programming (ILP), learning occurs from a knowledge base that contains a large number of examples. Storing such a knowledge base may consume a lot of memory. Often, there is a substantial overlap of information between different examples. To reduce memory consumption, we propose a method to represent a knowledge base more compactly. We achieve this by introducing a meta-theory able to build new theories out of other (smaller) theories. In this way, the information associated with an example can be built from the information associated with one or more other examples and redundant storage of shared information is avoided. We also discuss algorithms to construct the information associated with example theories and report on a number of experiments evaluating our method in different problem domains.     

Provable Protection against Web Application Vulnerabilities Related to Session Data Dependencies

Web applications are widely adopted and their correct functioning is mission critical for many businesses. At the same time, Web applications tend to be error prone and implementation vulnerabilities are readily and commonly exploited by attackers. The design of countermeasures that detect or prevent such vulnerabilities or protect against their exploitation is an important research challenge for the fields of software engineering and security engineering. In this paper, we focus on one specific type of implementation vulnerability, namely, broken dependencies on session data. This vulnerability can lead to a variety of erroneous behavior at runtime and can easily be triggered by a malicious user by applying attack techniques such as forceful browsing. This paper shows how to guarantee the absence of runtime errors due to broken dependencies on session data in Web applications. The proposed solution combines development-time program annotation, static verification, and runtime checking to provably protect against broken data dependencies. We have developed a prototype implementation of our approach, building on the JML annotation language and the existing static verification tool ESC/Java2, and we successfully applied our approach to a representative J2EE-based e-commerce application. We show that the annotation overhead is very small, that the performance of the fully automatic static verification is acceptable, and that the performance overhead of the runtime checking is limited.     

A Session Layer Concept for Overlay Networks

Current day mobility solutions are characterized by a number of essential restrictions that prevent them from being successful in an overlay network environment. This paper proposes 4 properties that mobility solutions must have to address these restrictions: application cooperation, higher layer mobility awareness, general applicability and protocol heterogeneity. Subsequently, a mobility solution that realizes all these properties is described. The solution introduces a session layer in the protocol stack that consists of two subsystems: the connection abstraction system and the address management system. Other mobility solutions found in the literature, session layer and others, typically only realize a subset of the four properties. Tom Mahieu holds a Bachelor's and Master's degree in computer sciences that he obtained at the Catholic University of Leuven. After obtaining his Master's degree in 1997, he was admitted into the Distrinet research group at the Department of Computer Science of the Catholic University of Leuven in Belgium as a research and teaching assistant, where he is current working on flexible component architectures for protocol stacks under the supervision of Prof. Pierre Verbaeten and Prof. Wouter Joosen. His Ph.D. dissertation deals with protocol stack support for applications that operate in dynamically changing network environments, such as mobile and wireless networks. Pierre Verbaeten is the head of the DistriNet research group. His main research interest is on system support and software engineering support for distributed systems. Under his supervision, DistriNet has grown to a group of 40 researchers (both Ph.D. students and postdocs) and 6 professors. He is responsible for teaching courses on computer architecture, computer networks and distributed systems. Wouter Joosen received a Ph.D. degree at the K.U. Leuven in 1996. His main research interests are in the areas of software architecture for distributed systems, aspect-oriented and component-based development, middleware, software security and embedded systems. Over the last 10 years, Wouter Joosen has been researching software development technologies (processes, architectures, notations and prototypes) that enable the construction and management of distributed applications that need support for a number of non-functional requirements, including security, real-time aspects, reliability and load balancing.