I.A. Henderson

Institut de Mathématiques de Toulouse

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J. McGhee

Semtech (United States)

P. McGlone

University of Strathclyde

Dominik Sankowski

Lodz University of Technology

Mary Newton

University of Southampton

M. El-Fandi

University of Tripoli

Felicity Perry

Agence française de développement

Gordon Waddell

University of Glasgow

Simon Zadek

Singapore Management University

Olivier Roustant

Université Toulouse III - Paul Sabatier

Pascal Noble

Université Toulouse III - Paul Sabatier

Cooperative Institutions

Agence française de développement

Inter-American Development Bank

Grantham College

Brazilian Development Bank

Organisation de Coopération et de Développement Economiques

University of Strathclyde

Directorate of Health

University of Łódź

University of Edinburgh

Ninewells Hospital

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Arbitrary space charge to bulk boundary model of Auger recombination for semiconductor power diodes

IEE Proceedings I Solid State and Electron Devices (1986)

I.A. Henderson J. McGhee

An arbitrary semiconductor junction is used to obtain an equation for junction current density in terms of the conditions at the boundaries between the space charge and the quasineutral bulk regions on each side of the junction. Included are the effects of recombination in the space charge volume as well as bandgap narrowing and ambipolar diffusion effects in the bulk regions at these boundaries. The equation also accounts for the effects of drift field, which is neglected in other theories, and demonstrates that it exerts a form of cross-coupled modulation upon current flow. Under certain conditions, it may be shown that the current density is largely determined by the carrier density gradient at the space charge to bulk boundaries. A solution for carrier density gradient, which is obtained by one integration of the diffusion equation, does not require a precise solution for carrier density profile and may be used to model bulk region Auger recombination with the aid of the derived equation for current density. This contribution may find use in the design of snubber diodes.

Ambipolar diffusion

Depletion region

Charge carrier

Charge density

Diffusion current

Diffusion capacitance

10.1049/ip-i-1.1986.0033

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Citations (1)

Development of a blood urea monitoring system for the closed loop control of dialysis.

PubMed (1993)

Paul T. Smirthwaite Anthony C. Fisher I.A. Henderson J. McGhee Nadiah Mokhtar

Optimal hemodialysis prescription through real-time blood urea (BU) monitoring and closed loop control of urea removal would be of significant clinical value. Progress toward a bedside BU analyzer and a control system is described here. An Amicon Minifilter inserted into the arterial bloodline provides a 1 ml/min stream of protein free ultrafiltrate for analysis. In vitro tests with bovine blood have shown excellent correlation between plasma (CP) and ultrafiltrate (CU) urea levels: CP = 0.961CU + 0.071, (n = 34, r = 0.998). In clinical hemodialysis studies, CU accurately represented the decay in CP. The BU analyzer uses a standard UV endpoint assay with a proportioning roller pump. The absorbance of the reacted mixture is read in a spectrophotometer after a 5 min incubation. For future control system design, the transfer function (TF) of the BU analyzer was measured using multifrequency binary testing. The data indicated that the analyzer may be modeled by a second order TF with a pure time delay. The same form of TF was also found to describe the Minifilter. Control of the removal rate of NaCl (substituted for urea) through automatic dialysate flow adjustment has been achieved with a simulated dialyzer-patient circuit (using a conductivity probe in place of the BU analyzer). A modified BU analyzer using computer controlled precision syringes for improved sample processing time and accuracy is also reported.

Absorbance

Dilution

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PDE constrained kernel regression methods

HAL (Le Centre pour la Communication Scientifique Directe) (2023)

I.A. Henderson

Kernel regression

Kernel (algebra)

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Automatic compensation of deadtime losses

Nuclear Instruments and Methods (1970)

D. Taylor S. Blatt I.A. Henderson

10.1016/0029-554x(70)90599-9

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Multifrequency binary testing in measurement and control

IEE Proceedings - Science Measurement and Technology (1994)

I.A. Henderson M. Al Muhaisni J. McGhee

The teaching of multifrequency binary testing (MBT) in measurement and control courses is proposed. This uses specialised types of information technology test signals known as multifrequency binary sequences (MBS). MBT has been successfully taught in the classroom and applied in the laboratory over the last 4 years. A typical selection of frequency response graphs, which were obtained in a measurement and control laboratory, is given.

10.1049/ip-smt:19949583

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Performance evaluation of a differential pressure cell model

IEEE Transactions on Instrumentation and Measurement (1998)

P. McGlone J. McGhee I.A. Henderson

This paper describes the development of a mathematical model of a differential pressure cell and its application in MATLAB. The model is also examined in SIMULINK, for the purposes of comparison of the model with the real world. Furthermore, we also describe the application of a system identification method using a multifrequency binary test signal, for comparison with the mathematical model. The method is applied to a pneumatic differential pressure cell. The exploration of the mathematical model shows that while the majority of the subsystems are nonlinear, they can adequately be approximated by Taylor polynomials. This facilitates the modeling of the subsystem elements as linear agents. The identification results show that the cell, composed of three main components-the diaphragm, pilot relay flapper/nozzle, and the feedback bellows-has an overall first-order linear response.

Bellows

Differential pressure

Identification

10.1109/19.746596

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Phase shift keyed technique for mirocomputer narrowband identification of a control system

I.A. Henderson J. McGhee

Narrowband

Identification

Phase control

10.1109/iccon.1989.770548

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New multisymbol multifrequency signals for identification of a linear system with non-linear distortion

M. El-Fandi J. McGhee I.A. Henderson P. McGlone

Many physical systems exhibit non-linear behaviour. This paper presents the use of new compact multifrequency data measurement signals to identify a linear system with a non-linear distortion at its output. The signals belong to the group of signals exhibiting antisymmetric, or half-period symmetric, properties. A theoretical framework is presented for a non-linear model when using antisymmetric test signals for frequency domain identification. It is shown that the effect of nonlinear distortion is reduced to about 50% by antisymmetric signals. This novel variety of compact multifrequency signals is used in a simulated test of a linear system with non-linear output distortion. A comparison between the new signal and a PRBS signal is reported.

Distortion (music)

Antisymmetric relation

Amplitude distortion

SIGNAL (programming language)

Phase distortion

Linear filter

10.1109/imtc.1999.776992

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Fundamentals of linear time-varying plant for diagnostic engineering

Springer eBooks (1990)

J. McGhee I.A. Henderson

Impulse response

Response time

10.1007/978-94-009-0431-6_63

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Roadmap for a sustainable financial system

Samuel Munzele Maimbo Simon Zadek Francisco Avendaño Katerina Levitanskaya Wenxin Li

Historically the financial system has responded to the needs of the time. A global consensus has arisen that sustainable growth will be one of the greatest challenges of the 21st century, as demonstrated by the United Nations (UN) Sustainable Development Goals (SDGs) adopted as part of its 2030 Agenda for Sustainable Development, along with the measures to combat climate change and adapt to its effects that are part of the Paris Agreement. As in previous structural transformations, the financial system will play a major role in this process: the full potential of the financial system needs to be harnessed to serve as an engine in the global economy’s transition toward sustainable development. The objective of this Roadmap is to propose an integrated approach that can be used by all financial sector stakeholders—both public and private, to accelerate the transformation toward a sustainable financial system. This approach can bring policy cohesiveness across ministries, central banks, financial regulators, and private financial sector participants to focus efforts. The ultimate vision that the Roadmap seeks to reach is one of a financial system that integrates sustainability considerations into its operations, including the full costing of positive and negative externalities that sustainability implies, leading to a reorientation of the flow of resources toward more inclusive and sustainable activities.

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Citations (54)