Mobility Management in beyond 3G-Environments

Beyond 3G-environments are typically defined as environments that integrate different wireless and fixed access network technologies. In this paper, we address IP based Mobility Management (MM) in beyond 3G-environments with a focus on wireless access networks, motivated by the current trend of WiFi, GPRS, and UMTS networks. The GPRS and UMTS networks provide countrywide network access, while the WiFi networks provide network access in local areas such as city centres and airports. As a result, mobile end-users can be always on-line and connected to their preferred network(s), these network preferences are typically stored in a user profile. For example, an end-user who wishes to be connected with highest bandwidth could be connected to a WiFi network when available and fall back to GPRS when moving outside the hotspot area.\ud In this paper, we consider a combination of MM for legacy services (like web browsing, telnet, etc.) using Mobile IP and multimedia services using SIP. We assume that the end-user makes use of multi-interface terminals with the capability of selecting one or more types of access networks\ud based on preferences. For multimedia sessions, like VoIP or streaming video, we distinguish between changes in network access when the end-user is in a session or not in a session. If the end-user is not in a session, he or she needs to be able to start new sessions and receive invitations for new sessions. If the end-user is in a session, the session needs to be handed over to the new access network as seamless as possible from the perspective of the end-user. We propose an integrated but flexible solution to these problems that facilitates MM with a customizable transparency to applications and end-users

Monitoring of distributed component interactions

We have describe a generic monitoring approach that can be used to enhance the quality of distributed component software. The generality of the approach is achieved through using reflective technology, i.e. CORBA Interceptors, CORBA POA and Java 2 features. A drawback of using interceptors is the fact that their interfaces have not been standardised so far. However, the process of standardisation is ongoing and has recently resulted in an OMG Joint Revised Submission called Portable Interceptors. Although the Java 2 API enables discovery of ‘forks’ in the execution, we find it lacking functionality for the purpose of discovering synchronisation points (e.g., ‘joins’) within multithreaded components

A consensus guide to capturing the ability to inhibit actions and impulsive behaviors in the stop-signal task.

Response inhibition is essential for navigating everyday life. Its derailment is considered integral to numerous neurological and psychiatric disorders, and more generally, to a wide range of behavioral and health problems. Response-inhibition efficiency furthermore correlates with treatment outcome in some of these conditions. The stop-signal task is an essential tool to determine how quickly response inhibition is implemented. Despite its apparent simplicity, there are many features (ranging from task design to data analysis) that vary across studies in ways that can easily compromise the validity of the obtained results. Our goal is to facilitate a more accurate use of the stop-signal task. To this end, we provide 12 easy-to-implement consensus recommendations and point out the problems that can arise when they are not followed. Furthermore, we provide user-friendly open-source resources intended to inform statistical-power considerations, facilitate the correct implementation of the task, and assist in proper data analysis

A Mechanism for Host Mobility Management supporting Application Awareness

Many approaches exist today that address the issues that arise when a mobile node changes its point(s) of attachment to the Internet. Mobile IP takes care of host mobility at the IP layer; others at the transport layer (Mobile SCTP) or at the application layer (SIP with re-invite). In practice, most of these approaches rely on functionality residing on the mobile host that scans, detects and activates the networks available through one or more network interfaces. The mechanism proposed in this paper takes into account that multiple of these approaches may be applied at the same time. It provides the applications on the mobile host with information about the state of the lower-layer mobility management protocols (such as Mobile IP) as well as the state and characteristics of the available network resources. Applications may consecutively adapt their behavior depending on this mobility process information and thus accommodate to the changed network connectivity conditions, possibly in an application specific manner. In this paper, we present the architecture of our mobility management mechanism. We also describe the implementation of our prototype and the results of experiments with the mechanism, thereby addressing the complexities of an integrated applicationaware mobility management system

Design and implementation of a framework for monitoring distributed component interactions

This paper presents a framework for monitoring component interactions. It is part of a larger component framework built on top of the CORBA distributed processing environment that supports development and testing of distributed software applications. The proposed framework considers an OMG IDL specification as a contract for distributed interactions and allows precise monitoring of interaction activities between application components. The developer is not burdened with monitoring issues because all the necessary code instrumentation is done automatically. The tester is given the opportunity to use monitoring facilities for observing interactions between distributed component applications. This paper explains the monitoring framework and reasons about its expressive power, accuracy and applicability. The approach is validated in a platform for design, development and deployment of on-line services