Decentralized Probabilistic World Modeling with Cooperative Sensing

Drawing on the projected increase in computing power, solid-state storage and network communication capacity to be available on personal mobile devices, we propose to build and maintain without prior knowledge a fully distributed decentralized large-scale model of the physical world around us using probabilistic methods. We envisage that, by using the multimodal sensing capabilities of modern personal devices, such a probabilistic world model can be constructed as a collaborative effort of a community of participants, where the model data is redundantly stored on individual devices and updated and refined through short-range wireless peer-to-peer communication. Every device holds model data describing its current surroundings, and obtains model data from others when moving into unknown territory. The model represents common spatio-temporal patterns as observed by multiple participants, so that rogue participants can not easily insert false data and only patterns of general applicability dominate. This paper aims to describe – at a conceptual level – an approach for building such a distributed world model. As one possible world modeling approach, it discusses compositional hierarchies, to fuse the data from multiple sensors available on mobile devices in a bottom-up way. Furthermore, it focuses on the intertwining between building a decentralized cooperative world model and the opportunistic communication between participants

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

Multimedia QoS adaptation for inter-tech roaming

We introduce a scalable application-level QoS adaptation service for roaming between wireless networks that are based on different technologies ('inter-tech' roaming). The service is part of a platform that supports the distribution of multimedia streams (e.g., a streamed TV channel) to mobile clients operating in a heterogeneous environment. Central to our approach is the notion of a service class, which is a domain-specific perceptual QoS level. Each domain in a wireless infrastructure must support a limited number of these service classes. Our adaptation service handles inter-tech roaming by handing a client off from one service class to another. We focus on the design of the adaptation service's client-side components. They combine the loss characteristics of the client's network interfaces with configurable policies to decide when to initiate a handoff to a target service class and when to complete it. We conclude with some experimental results

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

Context-Aware Middleware Support for the Nomadic Mobile Services on Multi-homed Handheld Mobile Devices

Nowadays, a variety ofhandheld mobile devices are capable of connecting to the Internet using multiple network interfaces. This is referred to as multi-homing. In addition to this, enriched computation resources allow them to host nomadic mobile services and provide these services to the clients located anywhere in the Internet. Potential advantages of multi-homing for nomadic mobile services typically includes: an increased service availability and improved service performance. However, applications running on the handheld mobile devices either do not, or cannot, exploit multi-homing. In this paper we address the problem ofproviding infrastructural support to the nomadic mobile services that can fully exploit multi-homing. To this end we propose to incorporate multi-homing functionality and support in a middleware layer to reduce the complexity of the design and maintenance of these services. The proposed solution uses a context-aware computing approach to realize this functionality. We report the initial experimental results in the remote telemonitoring of a patient equipped with a Body Area Network

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Emerging healthcare applications rely on personal mobile devices to monitor patient vital signs and to send it to the hospitals-backend servers for further analysis. However, these devices have limited resources that must be used optimally in order to meet the requirements of healthcare applications end-users: healthcare professionals and their patients. This paper reports on a case study of a cardiac telemonitoring application delivered by the so-called MobiHealth system. This system relies on a commercial device with multiple (wireless) network interfaces (NI). Our study focuses on how the choice of a NI affects the end-to-end applicationpsilas data delay (extremely important in case of patientpsilas emergency) and the energy consumption of the device (relating to the service sustainability while a patient is mobile). Our results show the trade-off between the delay and battery savings achieved by various NI activation strategies in combination with application-data flow adaptation. For a given mobile device, our study shows a gain of 40-90% in battery savings, traded against the higher delays (therefore applicable mainly in non-emergency cases). The insights of our studies can be used for application-data flow adaptation aiming at battery saving and prolonging devicepsilas operation for mobile patients