Chris Guy

Parallel architectures for high speed multipliers

The authors compare various array multiplier architectures based on (p,q) counter circuits. The tradeoff in multiplier design is always between adding complexity and increasing speed. It is shown that by using a (2,2,3) counter cell it is possible to gain a significant increase in speed over a conventional full-adder, carry-save array based approach. The increase in complexity should be easily accommodated using modern emitter-coupled-logic processes.<<ETX>>

Radio frequency energy harvesting in wireless sensor networks

As a vital factor affecting system cost and lifetime, energy consumption in wireless sensor networks (WSNs) has been paid much attention to. This article presents a new approach to making use of electromagnetic energy from useless radio frequency (RF) signals transmitted in WSNs, with a quantitative analysis showing its feasibility. A mechanism to harvest the energy either passively or actively is proposed.

TE-SIP server design for a SIP-over-MPLS based network

The next generation communication systems will provide multimedia services and will need to support high quality of service in a more flexible and intelligent manner than previous generations. In this paper, a network based on SIP (session initiation protocol) over MPLS (multi-protocol label switching) is proposed. A network architecture that adopts the SIP protocol as signaling to set up a call and MPLS as a core network forwarding mechanism is identified. A traffic engineering (TE)-SIP server is proposed, as part of a network architecture that will use a SIP session to provide a TE request for a SIP client. TE-server signaling mechanism and RSVP-TE LSP set-up are also discussed.

Co-ordinated Management of Intelligent Pervasive Spaces

The content of this paper is a snapshot of a current project looking at producing a real-time sensor-based building assessment tool, and a system that personalises workspaces using multi-agent technology. Both systems derive physical environment information from a wireless sensor network that allows clients to subscribe to real-time sensed data. The principal ideologies behind this project are energy efficiency and well-being of occupants; in the context of leveraging the current state-of-the-art in agent technology, wireless sensor networks and building assessment systems to enable the optimisation and assessment of buildings. Participants of this project are from both industry (construction and research) and academia.

Routing Protocols and Quality of Services for Security Based Applications Using Wireless Video Sensor Networks

Wireless video sensor networks have been a hot topic in recent years; the monitoring capability is the central feature of the services offered by a wireless video sensor network can be classified into three major categories: monitoring, alerting, and information on-demand. These features have been applied to a large number of applications related to the environment (agriculture, water, forest and fire detection), military, buildings, health (elderly people and home monitoring), disaster relief, area and industrial monitoring. Security applications oriented toward critical infrastructures and disaster relief are very important applications that many countries have identified as critical in the near future. This paper aims to design a cross layer based protocol to provide the required quality of services for security related applications using wireless video sensor networks. Energy saving, delay and reliability for the delivered data are crucial in the proposed application. Simulation results show that the proposed cross layer based protocol offers a good performance in term of providing the required quality of services for the proposed application.

A semiotic model for a self organising multi-agent system

Semiotics is the study of human use of signs and symbols, and humanspsila reaction to the interpretation of signs employed in communication and coordination. These elements of semiotics can be further expanded into four basic component modules; perceptual, epistemic (E), deontic (D) and axiological (A), originally based around a set of social norms. In this paper, we describe an organisational semiotic approach to designing intelligent agents and stakeholder negotiation based on these main components and a proof of concept in MASBO (multi-agent system for building control); a multi-agent system designed to provide co-ordinated management on building control HVAC systems within an intelligent building and CDE (collaborative design environment); a platform for stakeholders to negotiate their environmental specification.

Speed sensorless vector control of induction motors with parameter estimation

A novel rotor velocity estimation scheme applicable to vector controlled induction motors has been described. The proposed method evaluates rotor velocity, /spl omega//sub r/, online, does not require any extra transducers or injection of any signals, nor does it employ complicated algorithms such as MRACS or Kalman filters. Furthermore, the new scheme operates at all velocities including zero with very little error. The procedure employs motor model equations; however all differential and integral terms have been eliminated giving a very fast, low-cost, and practical alternative to methods currently available. Furthermore, the resistance estimation technique is also implemented. Not only does this ensure the tuned operation of the vector controller, but also results in the aforementioned velocity estimator being completely parameter insensitive. A detailed and thorough explanation of the underlying theory of both velocity and parameter estimation techniques is given. These are supported by various simulation tests, taking into consideration the PWM inverter, and practical results.

A mobility prediction scheme of LTE/LTE-A femtocells under different velocity scenarios

Femtocells have been standardized by the Third-Generation Partnership Project (3GPP) technical specifications to be placed indoors and in the cell edge. Femtocells extend the coverage area and fulfil the upcoming demands of higher data rates. However, as a result of the mass deployment of femtocells, users experience extra delay and unnecessary handovers. This can severely influence the Quality of Service (QoS) of delay-sensitive Real-Time (RT) applications such as Voice over Long Term Evolution (VoLTE). 3GPP LTE/LTE-A wireless networks aim to ensure seamless mobility and fast handover support to RT and non-RT application services under high mobility. Mobility prediction is an effective technique to identify a future evolved and Home NodeB (eNB/HeNB) in advance, improve overall network QoS and satisfy end-user experience. This study investigates the role of mobility prediction in reducing VoLTE end-to-end delay and handover delay under different User Equipment (UE) velocities in mixed femtocell and macrocell environments. A mobility prediction scheme based on the users path and Reference Signal Received Power and Reference Signal Received Quality (RSRP/RSRQ) measurements with mixed RT and non-RT traffic is proposed and then evaluated using a novel network model. The simulation results reveal that the proposed scheme has clearly reduced handover delay by 29%, kept VoLTE end-to-end delay within the ITU-T standard recommendations and maintained the desired QoS.

Virtualization for Cost-Effective Teaching of Assembly Language Programming

This paper describes a virtual system that emulates an ARM-based processor machine, created to replace a traditional hardware-based system for teaching assembly language. The virtual system proposed here integrates, in a single environment, all the development tools necessary to deliver introductory or advanced courses on modern assembly language programming. The virtual system runs a Linux operating system in either a graphical or console mode on a Windows or Linux host machine. Student feedback indicates that teaching with the virtual system has become progressively easier, clearer and more interesting while keeping staff support to a minimum. Since no software licenses or extra hardware are required to use the virtual system, students are able to carry their own ARM emulator with them on a USB memory stick. Institutions adopting this, or a similar, virtual system can also benefit by reducing the capital investment in hardware-based development kits, and by enabling distance-learning courses.

Fault Tolerant Integrated Memory Design

With today’s levels of integration, it is increasingly common to have complete systems such as digital controllers and other application specific processors implemented as single chips. As the number of devices in such chips increases the reliability of the system becomes an important issue. Memory has been singled out as the source of the majority of failures in such systems. Consequently, there is a perceived need to make these memory devices highly reliable.