Russell Standish | Kingston University, London (original) (raw)

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Papers by Russell Standish

Journal of Physical Chemistry B, Jun 15, 2004

The structural and dynamic properties of dioctadecyldimethylammoniums (DODDMA) intercalated into ... more The structural and dynamic properties of dioctadecyldimethylammoniums (DODDMA) intercalated into 2:1 layered clays are investigated using isothermal-isobaric (NPT) molecular dynamics (MD) simulation. The simulated results are in reasonably good agreement with the available experimental measurements, such as X-ray diffraction (XRD), atom force microscopy (AFM), Fourier transform infrared (FTIR), and nuclear magnetic resonance (NMR) spectroscopies. The nitrogen atoms are found to be located mainly within two layers close to the clay surface whereas methylene groups form a pseudoquadrilayer structure. The results of tilt angle and order parameter show that interior two-bond segments of alkyl chains prefer an arrangement parallel to the clay surface, whereas the segments toward end groups adopt a random orientation. In addition, the alkyl chains within the layer structure lie almost parallel to the clay surface whereas those out of the layer structure are essentially perpendicular to the surface. The trans conformations are predominant in all cases although extensive gauche conformations are observed, which is in agreement with previous simulations on n-butane. Moreover, an odd-even effect in conformation distributions is observed mainly along the chains close to the head and tail groups. The diffusion constants of both nitrogen atoms and methylene groups in these nanoconfined alkyl chains increase with the temperature and methelene position toward the tail groups.

arXiv (Cornell University), Feb 11, 2014

Annual Simulation Symposium, Sep 25, 2008

This paper describes a two phase model for simulating trust amongst clients and their wealth mana... more This paper describes a two phase model for simulating trust amongst clients and their wealth management advisors. In phase one an artificial life model was used to assess the dynamics of trust. In phase two the model is extended to utlise real data from a corporate database of client information. The alife model highlighted needs for information not captured directly, requiring sophisticated inference techniques. Fuzzy logic is used to describe client behaviour with rules found through evolutionary optimisation. Analysis of mutual information between time series of clients investments is used to determine links between clients.

Physical review, Nov 1, 1988

We derive exact equilibrium fluctuation expressions for the nonlinear Burnett coefficients for th... more We derive exact equilibrium fluctuation expressions for the nonlinear Burnett coefficients for the electrical conductivity of a fluid. The Burnett coefficients define a Taylor-series expansion of the conductivity in powers of the electrical current density. The fluctuation expressions may be calculated from an analysis of the time-dependent fluctuations of the equilibrium system constrained so that the mean electrical current is zero.

arXiv (Cornell University), Oct 15, 2002

, http://parallel.hpc.unsw.edu.au/rks Of all the issues discussed at Alife VII: Looking Forward, ... more , http://parallel.hpc.unsw.edu.au/rks Of all the issues discussed at Alife VII: Looking Forward, Looking Backward, the issue of whether it was possible to create an artificial life system that exhibits open-ended evolution of novelty is by far the biggest. Of the 14 open problems settled on as a result of debate at the conference, some 6 are directly, or indirectly related to this issue. Most people equate open-ended evolution with complexity growth, although a priori these seem to be different things. In this paper I report on experiments to measure the complexity of Tierran organisms, and show the results for a size-neutral run of Tierra. In this run, no increase in organismal complexity was observed, although organism size did increase through the run. This result is discussed, offering some signposts on path to solving the issue of open ended evolution.

Rosnick makes a lot of detailed points, but has failed to understand exactly what theory we are c... more Rosnick makes a lot of detailed points, but has failed to understand exactly what theory we are criticising. He organises his response according to three rather interwoven threads, to which we will only respond to the most important issues, rather than make a detailed point-by-point response. We will start with the issue that Rosnick completely failed to discuss (and which we therefore label as Thread 0): that the so-called profit-maximizing formula for an individual firmof equating marginal cost and marginal revenueprovably does not maximize profits in any industry structure apart from monopoly.

arXiv (Cornell University), Aug 17, 2005

I propose a simple representation language for undirected graphs that can be encoded as a bitstri... more I propose a simple representation language for undirected graphs that can be encoded as a bitstring, and equivalence is a topological equivalence. I also present an algorithm for computing the complexity of an arbitrary undirected network.

Journal of Physical Chemistry B, Jan 19, 2005

EcoLab is a system that implements an abstract ecology model.[3] It is written as a set of Tcl/Tk... more EcoLab is a system that implements an abstract ecology model.[3] It is written as a set of Tcl/Tk[2] commands so that the model parameters can easily be changed on the fly by means of editing a script. This document describes the class libraries that implement the dynamic array structures, and the interface to the Tcl interpreter, as well all the Tcl commands and variables that are defined in the EcoLab system. You should also examine the sample EcoLab script (ecolab.tcl) provided with the pacakge, and the sample problem scripts, e.g pred-prey.tcl and lifetime.tcl.

The paper presents an evolutionary dynamic economic model based on von-Neumann's work. Von N... more The paper presents an evolutionary dynamic economic model based on von-Neumann's work. Von Neuman's balanced growth solution is shown to be the long time average behaviour of the dynamic system, and that growth is found to be constrained by the productivities of key processes, called the generators of the economy. Some discussion is given about how to implement this model using the Ecolab modeling tool.

Complexity International, 1998

In the original speciication of the Ecolab model, spatial variation of the system's variables... more In the original speciication of the Ecolab model, spatial variation of the system's variables was included, with an additional migration operator introduced proportional to the divergence of the species density. Suitably discretized, the model then consists of a number of cells, each running the non-spatial Ecolab model, linked together by the migration operator. This paper reports on the implementation of such a cellular Ecolab. Originally, it was hoped that computational parallelism might be exploited by providing parallel versions of the underlying array operations used. However, it was found that the cost of the irregular data communication involved in the sparse matrix multiplication destroyed any gain from parallelism. Thus a Cellular Ecolab ooers a way of exploiting parallelism, that for certain situations as superlinear speedup is observed. As an example of the type of problem addressable by a spatial Ecolab, the species-area rule is examined, although the results are no...

The continuous spectrum of the linear Boltzmann operator with constant field is derived. It is fo... more The continuous spectrum of the linear Boltzmann operator with constant field is derived. It is found that a sufficiency relation for runaway phenomena is consistent with another sufficiency relation for the hydrodynamic regime to exist. There is a further class of systems whose behaviour lies in between these two extremes.

Arti cial Life as a eld of study was inaugurated by Chris Langton, who described it as the study ... more Arti cial Life as a eld of study was inaugurated by Chris Langton, who described it as the study of man-made systems exhibiting behaviours char-acteristic of life. As such it is complementary to traditional biology, locating life-as-we-know-it within the larger picture of life-as-it-could-be[19].

arXiv: Adaptation and Self-Organizing Systems, 2006

The issue of how to create open-ended evolution in an artificial system is one the open problems ... more The issue of how to create open-ended evolution in an artificial system is one the open problems in artificial life. This paper examines two of the factors that have some bearing on this issue, using the Tierra artificial life system. {\em Parsimony pressure} is a tendency to penalise more complex organisms by the extra cost needed to reproduce longer genotypes, encouraging simplification to happen. In Tierra, parsimony is controlled by the \verb+SlicePow+ parameter. When full parsimony is selected, evolution optimises the ancestral organism to produce extremely simple organisms. With parsimony completely relaxed, organisms grow larger, but not more complex. They fill up with ``junk''. This paper looks at scanning a range of \verb+SlicePow+ from 0.9 to 1 to see if there is an optimal value for generating complexity. Tierra (along with most ALife systems) use pseudo random number generators. Algorithms can never create information, only destroy it. So the total complexity of ...