Research
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His basic research themes are all in the field of ubiquitous
computing. Topics of particular interest are: collaborative sensor
networks, system architecture for mobile handheld computers, energy-efficient
wireless networking for multimedia traffic, heterogeneous wireless networks,
and reconfigurable computing.
This research has resulted in the Ph.D. thesis 'Mobile
Multimedia Systems'.
- Energy efficient sensor networks
The vision of ubiquitous computing requires the development of devices
and technologies, which can be pervasive without being intrusive. The
basic components of such a smart environment will be small nodes with
sensing and wireless communications capabilities, able to organize
flexibly into a network for data collection and delivery. Realising such
a network presents very significant challenges, especially at the
architectural and protocol/software level. Major steps forward are
required in the field of communications protocol, data processing, and
application support.
In the Eyes project (http://eyes.eu.org/), we will
develop the architecture and the technology needed for building
self-organizing and collaborative sensor
networks using reconfigurable smart sensor nodes, which are
self-aware, self-reconfigurable and autonomous. The goal is to develop
the architecture and the technology, which enables the creation of a new
generation of sensors that can effectively network together so as to
provide a flexible platform for the support of a large variety of mobile
sensor network applications. This technology will enable the creation of
a new generation of sensors, which can effectively network together so
as to provide a flexible platform for the support of a large variety of
mobile sensor network applications.
We will also show the feasibility of the concepts and technologies
developed by means of a prototype in which a sizable network of sensors
will be built and some example applications demonstrated.
- System architecture for mobile
multimedia computers
In the Moby Dick project we develop
and define the architecture of a new generation of mobile handheld
computers. The technologies of PDA, digital cellular phone and smart
card, when combined and integrated well, have the potential of replacing
all of the things people have to carry around with them by one small
device, the Mobile Digital Companion.
The Companions must meet several major requirements: high performance,
energy efficient, a notion of Quality of Service (QoS), small size, and
low design complexity. The design challenges lie primarily in the
creation of a single architecture that allows the integration of
security functions (e.g. payment), externally offered services (e.g.
airline ticket reservation), personality (i.e. these devices know what
their owners want), and communication.
The energy consumption due to the increasing demand for performance and
functionality will be the limiting factor for its capabilities.
Therefore reducing energy consumption plays a crucial role in the architecture.
The goal of the Pocket Companion's architecture is to optimise the
overall energy-performance of the system, and not performance alone. The
technology is used to decrease energy consumption and to increase
functionality to provide services such as multimedia devices,
compression and decompression, network access, and security functions.
Octopus, an energy efficient architecture for wireless multimedia
systems, is developed as part of the Moby Dick project. The approach is
based on dedicated functionality and the extensive use of energy
reduction techniques at all levels of system design. The unconventional
architecture saves energy by using system decomposition at different
levels of the archtecture and exploits locality of reference with
application domain specific modules. A reconfigurable internal
communication network switch, called Octopus, exploit locality of
reference and eliminates wasteful data copies.
- Energy-efficient wireless communication
for multimedia traffic.
The energy efficiency of wireless communication for multimedia traffic
with Quality of Service constraints is another main issue in the Moby
Dick project. We have developed an energy-efficient MAC protocol and
data link layer that is able to meet both requirements. Key to our approach
is a high degree of adaptivity. We have designed a MAC protocol (E2MaC)
and a network interface that achieves a good energy efficiency of the
wireless interface of the mobile and provides support for diverse
traffic types and QoS. At the transport layer we have developed E2TCP. This protocol not only has a higher energy efficiency than
TCP/IP, but it also manages to outperform TCP/IP on more traditional
performance metrics: throughput and latency.
In co-operation with Nedap N.V. in Groenlo the Netherlands we have
developed a wireless ATM communication network based on near-field RF
coupling. Cells have the size of a single office room. A mobile user can
use this network for running multi-media applications.
- Reconfigurable computing
In the Chameleon and
Gecko project we claim that a reconfigurable systems
architecture in combination with a QoS driven operating system that can
deal with the inherent dynamics of a mobile system, is of fundamental
importance to the success of flexible low-power handheld systems.
- Efficient architectures for seamless
services on heterogeneous wireless networks
The overall objective is to study, develop and validate heterogeneous
wireless network architectures, where the user is unbothered, but can
have full control, of the transport mechanisms and infrastructures used
to access and deliver the services requested, while the available
resources are used efficiently. Seamless
Services is a European research project investigating the
construction and use of future network information services for mobile
and non-mobile users. Our objective is to develop new innovative methods
and techniques for dynamic administration, representation, communication
and presentation of information and data - in order to enable seamless
access to networks services whatever access medium being used.
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