131 research outputs found
The calculation of bioavailable testosterone
No full textM. Haren, B.E.C. Nordin, C.E.M. Pearce, P. O’Loughlin, I. Chapman, J.E. Morley and G.A. Witterthttp://www.medimond.com/proceedings/moreinfo/20010615.ht
On the application of a polling model with non-zero walk times and priority processing to a medical emergency-room environment
No full textWe consider a queueing model used previously (Scholz and Sunde, 1998) to model a military high frequency (HF) communication network. Our discussion has moved from the original case where we aimed to maintain a high grade of service for the highest priority traffic classes. The characteristics of this network were that link set-up time was longer than the service time: it often took longer to establish the connection than for the actual transmission of the message. In (Pearce et al., 2000) we looked at a polling model with multiple servers and multiple queues, with each server visiting the queues according to a server allocation algorithm. The queueing system comprises a set of waiting lines to which requests arrive to be served by a pool of servers. We restrict our attention to the case where movement of servers from queue to queue does not happen in zero time. Our discussion focuses on the basics of the two-queue situation. We look at the way this queueing model can be applied to a medical emergency room, where setting up for certain surgery procedures takes longer than the actual procedures themselves. The significance of this model is the applicability to different problems, from communication networks to medical emergency rooms.Cicin-Sain, M. ; Pearce, C.E.M. ; Sunde, J
RMS values for force, stroke and deflection in a quarter-car model active suspension with preview
No full text© Swets & ZeitlingerIn the case of a quarter-car vehicle model incorporating an active suspension, the addition of preview to the system necessitates finding new techniques for the direct computation of rms values for control force, suspension stroke and tyre deflection on a random road. Here we obtain these rms values from the performance index components as derived analytically by means of matrix operations requiring the solution of Lyapunov equations and the use of similarity transformations. Some numerical examples and MATLAB programs are included.Thompson, A.G., Pearce, C.E.M
Additional obstacles in the implementation of computer technologies in small, non-English speaking countries
No full textThe purpose of this article is to point out some of the obstacles in the implementation of computer technologies that appear more often and are harder to solve in small, non-English speaking countries (Croatia as an example). Some of these problems are: language, character set, education, the problem of supporting science, staffing, the maintenance problem and the small market problem.Cicin-Sain, M. ; Pearce, C.E.M. ; Sunde, J
Geometric probability based stereological corrections
No full textIn mineral processing, a classic problem is that of estimating the particle composition distribution from particle sections. This problem occurs because mineralogical analysis is performed on particle sections rather than the particles. Thus one wishes to infer three-dimensional information (particle composition distribution) from two-dimensional information (particle sections). There are a number of different techniques available for estimating the particle composition distribution and these are called stereological corrections. This paper provides examples of very simple stereological corrections based on geometric probability equations as well as the principle of maximum entropy. The paper focuses on three methods. The first method is a simple entropy based model based on particle section information only. The second method also uses entropy, but the entropy is based on relating particles to particle sections, and is therefore more complex than the first. The third model uses both the particle section distribution and the linear intercept distribution. The most accurate model is that which uses both particle sections and linear intercepts
Midpoint Type Rules from an Inequalities Point of View
No full textThe article investigates interior point rules which contain the midpoint as a special case, and obtains explicit bounds through the use of a Peano kernel approach and the modern theory of inequalities. Thus the simplest open Newton-Cotes rules are examined. Both Riemann-Stieltjes and Riemann integrals are evaluated with a variety of assumptions about the integrand enabling the characterisation of the bound in terms of a variety of norms. Perturbed quadrature rules are obtained through the use of Grüss, Chebychev and Lupaş inequalities, producing a variety of tighter bounds. The implementation is demonstrated through the investigation of a variety of composite rules based on inequalities developed. The analysis allows the determination of the partition required that would assure that the accuracy the result would be within a prescribed error tolerance. It is demonstrated that the bounds of the approximations are equivalent to those obtained from a Peano kernel that produces Trapezoidal type rules
Long time scale molecular dynamics using least action
No full textWe present here an efficient method for evaluating molecular trajectories over long time scales. The method is based on optimisation of the path action defined by classical mechanics. We test the technique on non-trivial examples drawn from the literature and discuss the effectiveness of this approach in the study of molecular processes. Many of the present techniques for calculating molecular trajectories are limited computationally. Standard forward integration of Newton's equations of motion yields accurate results for a range of systems whose transition times are many orders of magnitude less than most biologically interesting processes. If one wants to extend these calculations to biologically relevant time scales, it is necessary to develop methodologies which avoid this limitation. The process outlined in this paper has been tested on simple systems using harmonic and Lennard--Jones potential energy functions. The algorithm yields stable trajectories and is adjustable to suite available computational resources. In theory, this algorithm is applicable to any molecular system where the initial and final states are known. This could include investigation of chemical reactions, ligand/receptor binding and work cycles of molecular machinery
Jensen's Inequality for Quasiconvex Functions
No full textSome inequalities of Jensen type and connected results are given for quasiconvex functions on
convex sets in real linear spaces
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