Eric Graeme Chester

In this paper, we demonstrate that a low power flash FPGA based micro-system can provide a low power programmable interface for closed-loop brain implant inter- faces. The proposed micro-system receives recording local field potential (LFP) signals from an implanted probe, performs closed-loop control using a first order control system, then conver...

In this paper, the wireless data and power transfer for a novel optogenetic visual cortex implant system was demonstrated by using pork tissue mimic in-vitro at the ISM 2.4 GHz and 13.5 MHz frequency band respectively. The observed data rate was 120 kbps with no loss in data for up to a thickness of 35 mm in both water & pork. To increase the power...

Presented is a methodology of conversion of a conventional colour measure, e.g. 24-bit colour, to a neuromorphic representation for use with epiretinal prostheses. The conversion implemented, for a 4 by 4 image, within a field programmable gate array outputs three groups of timing signals. These three groups correspond to red (R), green (G) and blu...

Market forces are continually demanding devices with increased functionality/unit area; these demands have been satisfied through aggressive technology scaling which, unfortunately, has impacted adversely on the global interconnect delay subsequently reducing system performance. Line drivers have been used to mitigate the problems with delay; howev...

We present in this work the analysis, investigation and experimental measurements for a high data rate (HDR), modulator design for biodevice telemetry over wireless inductive coupling. That has been achieving by programming a code description and implementation on an FPGA/CLPD. A new VHDL designed n-PSK modulator programmed with VHDL code generates...

A reconfigurable network architecture applied to spiking neural networks is presented. For hardware platforms for neural networks that implement some degree of realism of interest to neuroscientists, connectivity between neurons can be a major limitation. Recent data indicates that neurons in the brain form clusters of connections. Through the comb...

The aim of this paper is to study the impact of security protocols on the quality of Voice over Internet Protocol (VoIP) in a third generation (3G) network. Long distance calls are expensive and the potential of cost saving is the most attractive feature in VoIP. In VoIP, voice traffic travels using the Internet protocol instead of using a conventi...

In this paper we present a study on the potential benefit that mutual coupling reduction can have on MIMO capacity. A simple line fed microstrip patch array is designed on a relatively thick substrate and then compared with the same structure having three periods of mushroom EBG (electromagnetic band gap) elements in addition to variable offset sup...

Not Available

This paper describes a location system based on RFID technology. This system can be used to map the image of an endoscope. Compared with other endoscope location systems, this is a wireless system. The transponder mounted along the shaft of an endoscope does not increase the size of the endoscope or affect the flexibility of endoscope. We build the...

A parametric study on the physical attributes of a planar inverted F antenna is to be presented. The PIFA under investigation does not have a shorting via to the ground in contrast to most other designs. The antenna is printed on a high frequency laminate, thus maintaining low profile, ease of fabrication and good fabrication tolerances. Varied ant...

With the convergence of mobile telephony and the Internet, it seems that future telephony data will be transferred on VoIP datagram. Mobility will affect the overall system performance especially for voice communication. Thus, maintaining the quality of voice is necessary. It is important to guarantee that the end-to-end delay must be kept at a cer...

This paper focuses on the performance of traffic mix which consists of both voice and data services. The paper deals with intra-frequency soft handover in a 3G networks where mobile stations are connected simultaneously to several base stations. The QoS of voice for mobile users in the mixed traffic environment is estimated. The results are compare...

Third generation (3G) and the Internet are identified as the main drivers for the future generation mobile telecommunication market. Several concerns arise when Internet protocol (IP) transport is introduced. Applications such as streaming and packet telephony will cause network congestion. This will affect the quality of service (QoS) of voice com...

The list decoding algorithm can outperform the conventional unique decoding algorithm by producing a list of candidate decoded messages. An efficient list decoding algorithm for algebraic-geometric (AG) codes and Reed-Solomon (RS) codes has been developed by Guruswami and Sudan, called the Guruswami-Sudan (GS) algorithm. The algorithm includes two...

In this article, we present a linear printed dipole array of two radiating elements for potential use in IEEE 802.1 In wireless local area networks. The dipoles are fed through a microstrip balun and are oriented in a fashion that introduces pattern diversity. Advantages of the proposed design are low cost, ease of fabrication and high impedance ba...

List decoding is a novel method for decoding Reed – Solomon (RS) codes that generates a list of candidate transmitted messages instead of one unique message as with conventional alge-braic decoding, making it possible to correct more errors. The Guruswami – Sudan (GS) algorithm is the most efficient list decoding algorithm for RS codes. Until recen...

As mobile communication involves transferring an ongoing call from one cell to another as the user moves through the coverage area, it is important to study the factors that affect the overall performance. This paper presents the process of voice over Internet Protocol (VoIP) in a third generation (3G) network with performance was evaluation. The p...

This paper presents an analytical study on voice over Internet protocol (VoIP) performance in a third generation (3G) network evaluated under certain IP conditions. The mouth-to-ear delay is analysed using different types of coding schemes to estimate the actual voice packet arrival as traffic sources are very bursty in nature. The simulation resul...

The asymptotic spectral efficiency of multicarrier CDMA (MC-CDMA) with multiple transmit and receive antennas is analysed in this paper. The closed-form spectral efficiency is derived when matched filter and minimum mean square error (MMSE) front ends are employed. We consider the effect of the number of transmit and receive antennas on the perform...

In this paper, a novel time domain upsampling linear receiver is proposed for an asynchronous multicarrier code division multiple access system in frequency-selective Rayleigh fading channels. After anti-aliasing filtering, the received discrete-time upsampled signal is processed by a finite-impulse-response (FIR) filter at the receiver without any...

The next generation of mobile networks will operate with CDMA and support multimedia services. Admission control, which can be categorized to resource management, plays an important role in mobile cellular systems. It can support quality of service (QoS) since it makes a decision about whether a new call should be admitted into the system. The curr...

Previous work on asynchronous communication mechanisms (ACMs) has not dealt with buffered forms (n > l). This paper describes a systematic design/synthesis process for ACMs with arbitrary buffer size, a series of resulting buffered ACM algorithms, and the modelling and simulation of these ACMs using Matlab, putting ACMs (esp. buffered ones) in the...

Architecture of a cross-coupled decision feedback detector is suggested to reduce both inter-symbol-interference and multiple-access interference for an asynchronous multicarrier CDMA scheme for the reverse link of a mobile communication system. Results show that an enhancement in capacity and good interference resistance are obtained.

Not Available

An asynchronous multicarrier code division multiple access (MC-CDMA) scheme over frequency selective multipath Rayleigh fading channels for the reverse link of a mobile communication system is investigated when the delay spread is in excess of a symbol interval. An architecture of a centralized decision feedback equalizer (CDFE) based on the minimu...

A field enhanced diffusion (FED) model is proposed for the observed phenomenon of dopant migration within 4H silicon carbide (4H–SiC) during high temperature annealing. The proposed FED model is based on the combined effects of both dopant diffusion and the in-built p–n junction electric field gradients found within the doped substrate resulting fr...

Data transmission over HF channels is subject to phenomena of dispersion, absorption and multiple paths. Performance may be improved by using orthogonal frequency division multiplexing spread spectrum (OFDM-SS) systems. In OFDM-SS systems, transmitting data over slowly varying multi-path channels, both intersymbol interference (ISI) and multiple-ac...

In this paper, a novel nonlinear adaptive beamformer based on robust statistics is developed for DS-CDMA receiver in mitigating impulsive noise effects. The proposed structure incorporated a nonlinearity parameter into the nonlinear LMS algorithm in order to stabilise the convergence during the adaptation period. The achieved results show that the...

It is shown that a 4-fold improvement in static and dynamic CMOS circuit performance can be achieved by the introduction of strained silicon MOSFETs. A 2-fold improvement is obtained using pseudomorphic SiGe pMOSFETs in static CMOS. The industry standard compact model BSIM3v3 is able to capture the features of buried channel and surface channel SiG...

This paper shows that the internal noise in a bistable exhibits a Gaussian distribution, and is close to the value expected from thermal agitation. We describe a random number generator based on this property that is capable of on chip integration, and is a primary source of high entropy data at 100MHz. The device is held close to metastability by...

A design improvement for comer reflector antennas is presented based on the use of three cylindrical reflecting surfaces. A significant increase in antenna gain is achieved with almost the same directivity. The main benefit of this design is to enable the development of small and low cost antennas for radio communication links.

Experimental evidence is given for a newly observed surface morphological phenomenon (step bunch bleed) and its implications for device fabrication constraints in ion implanted 4H-silicon carbide (4H-SiC) are discussed. Step bunch bleed is the result of surface step bunching spreading during a high-temperature anneal process to bridge closely adjac...

Experimental evidence is given for boron (B) enhanced diffusion of nitrogen (N) in ion-implanted 4H silicon carbide (4H-SiC), when a nitrogen implant is co-doped within an existing boron p -type well. The co-implanted nitrogen is shown to diffuse continuously with time when samples are annealed at 1600 ° C —with little movement of the boron p -well...

A physical model is proposed for the observed Transient Enhanced dopant Diffusion (TED) effects found in 4H-SiC during high temperature annealing. The proposed model is based on the effects of dopant diffusion combined with the action of the in built p-n junction electric field gradients found within the doped substrate resulting from the presence...

An automated knowledge-based vision system for skeletal growth estimation in children is reported in this paper. Images were obtained from hand radiographs of 32 male and 25 female children of age 1-16 yr. Phalanx bones were automatically localized and segmented using hierarchical inferences and active shape models, respectively. A number of shape...

The Codesign Finite State Machine (CFSM) formal model provides a suitable approach for the description of hardware/software systems. The POLIS tool from Berkeley implements the CFSM methodology but currently relies on the textually based Esterel specification language as a high level for the description of individual CFSMs. The designer must then u...

This paper presents an automated growth estimation system based on Bayesian principle by using knowledge-based vision methods to localise and segment bones in hand radiographs. Traditional manual methods have been tedious and prone to inter and intra observer inconsistencies. A segmentation algorithm known as active models (ASM) followed by a hiera...

Programmable logic controllers (PLCs) are commonly used in the implementation of industrial control systems. Statecharts are a suitable tool for the specification of complex reactive control systems. Statemate produced by iLogix Inc. enables the design, validation and simulation of a statechart model. The authors (1998) have previously developed a...

A robust contour detection algorithm is presented for noisy images characterised by close objects. The proposed approach uses an adaptive multi-scale edge tracking scheme based on active shape models and the wavelet transform. This adaptive method effectively adjusts the appropriate Gaussian function bandwidth according to the noise level so that c...

This paper considers a new approach of stochastic image modelling (SIM) for unsupervised textured image segmentation. In robust SIM, an efficient Gibbs Markov random field (GMRF) is derived in order to consider only the relationship between a centre pixel and its neighbourhood without a priori knowledge of the distributions of texture patterns in a...

This paper presents a knowledge-based automated vision system to segment bones in a child's hand radiograph image, and to determine growth progress using decision theoretic approaches. A hierarchical knowledge-based localisation scheme is used to localise bones in the hand radiograph image. Bone contour detection is then implemented with further kn...

A method is presented for the pre-processing of radiographs in the automated determination of skeletal maturity. By linearly combining several source images, a density range enhancement is obtained without the creation of edge artefacts. An increase of bit depth of 1 bit was obtained, and density range was improved by 1 OD.

A method is presented for the pre-processing of radiographs in the automated determination of skeletal maturity. By linearly combining several source images, a density range enhancement is obtained without the creation of edge artefacts. An increase of bit depth of 1 bit was obtained, and density range was improved by 1 OD.

Harmonic-free vector control, in which both the phase and amplitude of a three-phase current are controlled digitally to within close limits, is a common requirement in many power conversion applications. These include the control of three-phase motors, and the conversion of electrical power from three-phase AC to DC, or the inverse, with low suppl...

It has been shown that an objective measurement of fragmentation is possible, leading to an alternative method for planning arrhythmia surgery. Although initial trials are based on limited statistical data, the results appear promising. Future refinements would include the choice of an optimal coherence template and fuzzy set membership functions o...

A method for bone segmentation in hand radiographic images using an intensity based edge detection scheme is presented. Bone segmentation is an intermediate level processing stage for an automated vision system for skeletal assessment of children. An inherent problem with hand radiographic images is the uneven contrast that is manifested by an incr...

Accurate localisation of arrhythmogenic origin is necessary for successful surgery on patients with ventricular arrhythmia's. At the Freeman Hospital, Newcastle upon Tyne a technique known as fragmentation mapping has been developed. The intrinsic advantage of fragmentation mapping is that if does not require ventricular tachycardia (VT) to be indu...

Accurate localisation of arrhythmogenic origin is necessary for successful surgery on patients with ventricular arrhythmias, and fragmentation mapping is one of the principal techniques used intraoperatively for this purpose. Fragmentation mapping is normally based on subjective characterisation of fragmented cardiac myopotentials. These fragmented...

It is shown that a digital phase locked loop can be designed to perform the functions of capturing fundamental of an input reference wave, and producing sine and cosine values of the phase angle to a 16 bit accuracy. Digital differential analyzers are used for continuous calculation of the sine and cosine, since the simplicity of the hardware requi...

The use of semicustom technology in the teaching of IC design courses is described. The issues of appropriateness and cost of the technology are discussed with regard to the educational aims of the courses. A solution is offered to the problem of testing fabricated designs without a large investment in ATE.

A brief description of the Silvar-Lisco HELIX simulator is presented, followed by two example models. The first is a model of a standard component for which a data sheet is available. The second is a high-level model of a proposed circuit design for which no detailed information yet exists.

The testing of VLSI circuits is becoming progressively more difficult as device densities increase. This has brought about several proposals for designing VLSI circuits with testability built in. A method is presented in the paper for the design of easily testable VLSI circuits with a view to producing fault tolerant systems. A microprocessor datap...

The testing of VLSI circuits is becoming progressively more difficult as device densities increase. This has brought about several proposals for designing VLSI circuits with testability built in. A method is presented in the paper for the design of easily testable VLSI circuits with a view to producing fault tolerant systems. A microprocessor datap...

An adaptable device that will be a useful tool to further understanding of the operation of the mammalian nervous system, including the brain, is discussed. An example spiking neuron model that has been manufactured at 130nm is presented. In hardware platforms for neural networks that implement some degree of realism of interest to neuroscientists,...

Call admission control (CAC) plays a vital role to ensure the desired quality of service (QoS) and is used widely in mobile networks within joint control protocols (1-5). A previous study (1) has proposed an efficient interactive CAC called "CICAC" based on distributed constrained power control (DCPC). In this work, we present a new interactive CAC...

As important communication components of asynchronous systems, the ACMs have been studied for many years. A well known Pool using 4 data slots was proposed by H. R. Simpson. However, under certain assumptions, the number of slots in shared memory can be reduced to 3. Mutex, David Cells and SYNCs are used here to implement the 3-slot Signal. The des...

List decoding algorithms improve the error-correction performance of a code by generating a list of possible transmitted messages instead of one unique message as with conventional algebraic decoders, making it possible to correct errors beyond half the hamming distance boundary d/2. In this paper, we present new simulation results for Reed-Solomon...

Thesis (Ph. D.)--University of Newcastle upon Tyne, 1982.