A Rewriting-Logic-Based Technique for Modeling Thermal Systems

This paper presents a rewriting-logic-based modeling and analysis technique for physical systems, with focus on thermal systems. The contributions of this paper can be summarized as follows: (i) providing a framework for modeling and executing physical systems, where both the physical components and their physical interactions are treated as first-class citizens; (ii) showing how heat transfer problems in thermal systems can be modeled in Real-Time Maude; (iii) giving the implementation in Real-Time Maude of a basic numerical technique for executing continuous behaviors in object-oriented hybrid systems; and (iv) illustrating these techniques with a set of incremental case studies using realistic physical parameters, with examples of simulation and model checking analyses.Comment: In Proceedings RTRTS 2010, arXiv:1009.398

Aspects of real-time digital spectral analysis

In the field of control engineering there is a need to study the dynamic behaviour of systems which are subjected to random disturbances. A technique which is of great practical use is to describe the dynamic properties as a function of frequency. This involves determining the frequency content, or spectrum, of the disturbances, and the frequency response function of the system. There are many analogue and digital techniques which are designed for this type of spectral analysis. However, digital computer techniques are often avoided because they are slow, and data must be collected 'off-line'. A recently discovered computational method, termed the fast- Fourier-transform (FFT), enables digital spectral analysis to be carried- out in a much shorter time than was previously possible. In view of this discovery it was decided to develop digital computer programmes which would overcome the disadvantages of conventional digital spectral analysis. Using these programmes a computer would be connected, via an analogue to digital interface, to the signal source, and would process the data as it entered the computer. In the jargon of computing, the computer would be 'on-line' and analyzing the spectra in 'real-time'. The first part of the project consisted of an investigation of the FFP when programmed for an on-line digital computer. The results of this investigation showed that a rapid, accurate, and compact FFT could be programmed by using fixed-point arithmetic, and coding in an assembly language. The speed of the transform was sufficient to allow spectral analysis over a frequency range useful in control applications. Two on-line computer programmes based upon the YPP were then written; one for 'real-time' spectral analysis of a single record, and another for the 'real-time' estimation of the frequency response function relating two signals. In order that the results of these programmes could be sensibly interpreted, a statistical study was made of the spectral estimators used in the programmes. Arising from this study, several contributions to the field of digital spectra. analysis were made. These were : - 1) A more general covariance relationship for cross-spectral estimators. 2) An examination of aliasing in digital spectral estimators. 3) Some theoretical results concerning spectral estimators for closed loop systems with random disturbances inside the loop, Some experimental work was conducted with the real-time' spectral analysis programmes, and it was concluded that the tec: inique is more powerful than conventional digital. methods because it is on- line, and can provide estimates with improved resolution and statistical stability. Real-time digital spectral analysis methods also have the advantage that they may be simply and quickly modified to suit specific applications

A Plea for More Theory in Molecular Biology

The integrationist principles of systems theory have proven hugely successful in the physical sciences and engineering. It is an underlying assumption made in the systems approach to biology that they can also be used to understand biological phenomena at the level of an entire organism or organ. Within this holistic vision, the vastmajority of systems biology research projects investigate phenomena at the level of the cell, with the belief that unifying principles established at the most basic level can establish a framework within which we may understand phenomena at higher levels of organization. In this spirit, and to use a celestial analogy, if a disease effecting an organ or entire body is our universe of discourse, then the cell is the star we gaze at. In building an understanding of disease and the effect of drugs, systems biology makes an implicit assumption about direct causal entailment between cell function and physiology. A skeptic might argue that this is about the same as trying to predict the world economy from observations made at a local supermarket. However, assuming for the moment that the money and hope we are investing inmolecular biology, genomics, and systems biology is justified, how should this amazing 118 O. Wolkenhauer, M. Mesarovi´c, P. Wellstead intellectual achievement be possible? In this chapter we argue that an essential tool to progress is a systems theory that allows biological objects and their operational characteristics to be captured in a succinct yet general form. Armed with this conceptual framework, we construct mathematical representations of standard cellular and intercellular functions which can be integrated to describe more general processes of cell complexes, and potentially entire organ

Bond graph modelling of chemoelectrical energy transduction

Energy-based bond graph modelling of biomolecular systems is extended to include chemoelectrical transduction thus enabling integrated thermodynamically-compliant modelling of chemoelectrical systems in general and excitable membranes in particular. Our general approach is illustrated by recreating a well-known model of an excitable membrane. This model is used to investigate the energy consumed during a membrane action potential thus contributing to the current debate on the trade-off between the speed of an action potential event and energy consumption. The influx of Na+ is often taken as a proxy for energy consumption; in contrast, this paper presents an energy based model of action potentials. As the energy based approach avoids the assumptions underlying the proxy approach it can be directly used to compute energy consumption in both healthy and diseased neurons. These results are illustrated by comparing the energy consumption of healthy and degenerative retinal ganglion cells using both simulated and in vitro data

Computerised interpretation of fetal heart rate during labour (INFANT) : a randomised controlled trial

Background: Continuous electronic fetal heart-rate monitoring is widely used during labour, and computerised interpretation could increase its usefulness. We aimed to establish whether the addition of decision-support software to assist in the interpretation of cardiotocographs affected the number of poor neonatal outcomes. Methods: In this unmasked randomised controlled trial, we recruited women in labour aged 16 years or older having continuous electronic fetal monitoring, with a singleton or twin pregnancy, and at 35 weeks' gestation or more at 24 maternity units in the UK and Ireland. They were randomly assigned (1:1) to decision support with the INFANT system or no decision support via a computer-generated stratified block randomisation schedule. The primary outcomes were poor neonatal outcome (intrapartum stillbirth or early neonatal death excluding lethal congenital anomalies, or neonatal encephalopathy, admission to the neonatal unit within 24 h for >= 48 h with evidence of feeding difficulties, respiratory illness, or encephalopathy with evidence of compromise at birth), and developmental assessment at age 2 years in a subset of surviving children. Analyses were done by intention to treat. This trial is completed and is registered with the ISRCTN Registry, number 98680152. Findings: Between Jan 6, 2010, and Aug 31, 2013, 47 062 women were randomly assigned (23 515 in the decision-support group and 23 547 in the no-decision-support group) and 46 042 were analysed (22 987 in the decision-support group and 23 055 in the no-decision-support group). We noted no difference in the incidence of poor neonatal outcome between the groups-172 (0.7%) babies in the decision-support group compared with 171 (0.7%) babies in the no-decision-support group (adjusted risk ratio 1.01, 95% CI 0.82-1.25). At 2 years, no significant differences were noted in terms of developmental assessment. Interpretation: Use of computerised interpretation of cardiotocographs in women who have continuous electronic fetal monitoring in labour does not improve clinical outcomes for mothers or babies

Smartphone app-induced habit: a therapeutic component in psychological treatment for obsessive-compulsive disorder

© 2023 Published by Elsevier B.V. This is an open access conference article under the Creative Commons Attribution-NonCommercial-NoDerivatives CC BY-NC-ND licence, https://creativecommons.org/licenses/by-nc-nd/4.0/Peer reviewe

Re-visiting Meltsner: Policy Advice Systems and the Multi-Dimensional Nature of Professional Policy Analysis

10.2139/ssrn.15462511-2

Effect of Groundwater Pumping on Seawater Intrusion in Coastal Aquifers

Many aquifers around the globe are located in coastal areas and are thus subjected to the seawater intrusion phenomenon. The growth of population in coastal areas and the conjugate increase in human, agricultural, and industrial activities have imposed an increasing demand for freshwater. This increase in water demand is often covered by extensive pumping of fresh groundwater, causing subsequent lowering of the water table (or piezometric head) and upsetting the dynamic balance between freshwater and saline water bodies. The classical result of such a development is seawater intrusion. This paper presents a review for the seawater intrusion phenomenon in coastal aquifers. The effect of pumping activities on the seawater intrusion in the Nile Delta aquifer of Egypt is investigated. It was concluded that any additional pumping should be located in the middle Delta and avoided in the eastern and western sides of the Delta