Imagine the Possibilities: Information without Overload

Information is often modelled as a set of relevant possibilities, treated as logically possible worlds. However, this has the unintuitive consequence that the logical consequences of an agent's information cannot be informative for that agent. There are many scenarios in which such consequences are clearly informative for the agent in question. Attempts to weaken the logic underlying each possible world are misguided. Instead, I provide a genuinely psychological notion of epistemic possibility and show how it can be captured in a formal model, which I call a fan. I then show how to use fans to build formal models of being informed, as well as knowledge, belief and information update.

Spatio-temporal filtering properties of a dendritic cable with active spines: a modeling study in the spike-diffuse-spike framework

The spike-diffuse-spike (SDS) model describes a passive dendritic tree with active dendritic spines. Spine-head dynamics is modeled with a simple integrate-and-fire process, whilst communication between spines is mediated by the cable equation. In this paper we develop a computational framework that allows the study of multiple spiking events in a network of such spines embedded on a simple one-dimensional cable. In the first instance this system is shown to support saltatory waves with the same qualitative features as those observed in a model with Hodgkin-Huxley kinetics in the spine-head. Moreover, there is excellent agreement with the analytically calculated speed for a solitary saltatory pulse. Upon driving the system with time varying external input we find that the distribution of spines can play a crucial role in determining spatio-temporal filtering properties. In particular, the SDS model in response to periodic pulse train shows a positive correlation between spine density and low-pass temporal filtering that is consistent with the experimental results of Rose and Fortune [1999, Mechanisms for generating temporal filters in the electrosensory system. The Journal of Experimental Biology 202, 1281-1289]. Further, we demonstrate the robustness of observed wave properties to natural sources of noise that arise both in the cable and the spine-head, and highlight the possibility of purely noise induced waves and coherent oscillations.

El reconocimiento y los medios

Recognition and the media recopila los aportes al campo de la comunicación y al estudio de los medios que viene desarrollando Rousiley Maia sobre la base de la teoría crítica de Axel Honneth, desde 1998 tras su formación posgradual en Política en la Universidad de Nottingham (UK) y como directora del grupo de investigación Pesquisa em Mídia e Esfera Pública (EME), de la Universidade Federal de Minas Gerais (UFMG) en Brasil. El objetivo general del libro es ofrecer luces respecto a lo que la autora denomina ‘interfaces’ –las posibles conexiones– entre la teoría del reconocimiento de Honneth, la teoría política de la comunicación y la investigación empírica de los medios de comunicación, es decir, entre los estudios de los medios y los estudios de las luchas por el reconocimiento, en dinámicas que involucran la democracia, la esfera pública, la identidad, las minorías y grupos menos favorecidos, el compromiso cívico y los movimientos sociales.

Laying out the future of final-form digital documents

It is just over 20 years since Adobe's PostScript opened a new era in digital documents. PostScript allows most details of rendering to be hidden within the imaging device itself, while providing a rich set of primitives enabling document engineers to think of final-form rendering as being just a sophisticated exercise in computer graphics. The refinement of the PostScript model into PDF has been amazingly successful in creating a near-universal interchange format for complex and graphically rich digital documents but the PDF format itself is neither easy to create nor to amend. In the meantime a whole new world of digital documents has sprung up centred around XML-based technologies. The most widespread example is XHTML (with optional CSS styling) but more recently we have seen Scalable Vector Graphics (SVG) emerge as an XML-based, low-level, rendering language with PostScript-compatible rendering semantics. This paper surveys graphically-rich final-form rendering technologies and asks how flexible they can be in allowing adjustments to be made to final appearance without the need for regenerating a whole page or an entire document. Particular attention is focused on the relative merits of SVG and PDF in this regard and on the desirability, in any document layout language, of being able to manipulate the graphic properties of document components parametrically, and at a level of granularity smaller than an entire page.

Artificial Immune Tissue using Self-Organizing Networks

As introduced by Bentley et al. (2005), artificial immune systems (AIS) are lacking tissue, which is present in one form or another in all living multi-cellular organisms. Some have argued that this concept in the context of AIS brings little novelty to the already saturated field of the immune inspired computational research. This article aims to show that such a component of an AIS has the potential to bring an advantage to a data processing algorithm in terms of data pre-processing, clustering and extraction of features desired by the immune inspired system. The proposed tissue algorithm is based on self-organizing networks, such as self-organizing maps (SOM) developed by Kohonen (1996) and an analogy of the so called Toll-Like Receptors (TLR) affecting the activation function of the clusters developed by the SOM.

Simulation Optimization of the Crossdock Door Assignmnet Problem

The purpose of this report is to present the Crossdock Door Assignment Problem, which involves assigning destinations to outbound dock doors of Crossdock centres such that travel distance by material handling equipment is minimized. We propose a two fold solution; simulation and optimization of the simulation model - simulation optimization. The novel aspect of our solution approach is that we intend to use simulation to derive a more realistic objective function and use Memetic algorithms to find an optimal solution. The main advantage of using Memetic algorithms is that it combines a local search with Genetic Algorithms. The Crossdock Door Assignment Problem is a new domain application to Memetic Algorithms and it is yet unknown how it will perform.

Sensing Danger: Innate Immunology for Intrusion Detection

The immune system provides an ideal metaphor for anomaly detection in general and computer security in particular. Based on this idea, artificial immune systems have been used for a number of years for intrusion detection, unfortunately so far with little success. However, these previous systems were largely based on immunological theory from the 1970s and 1980s and over the last decade our understanding of immunological processes has vastly improved. In this paper we present two new immune inspired algorithms based on the latest immunological discoveries, such as the behaviour of Dendritic Cells. The resultant algorithms are applied to real world intrusion problems and show encouraging results. Overall, we believe there is a bright future for these next generation artificial immune algorithms

Open Access Repositories & Scholarly Publication

This presentation briefly covers some of the issues around Open Access as it pertains to institutional repositories in the UK higher educational sector. It includes an overview of the current activities of SHERPA, along with the benefits, concerns and potential resolutions of issues in the open access sector. Some speculation as to future trends and developments in scholarly publishing and open access is included. The presentation is in no way comprehensive, and is intended to give an overview of the subject to a general audience who will be engaged with academic and scholarly publishing on a variety of levels.

Belief and Bounded Rationality

Predictive accounts of belief ascription, either following the principle of charity or Dennett's intentional stance, have proved popular recently. However, such accounts require us first to treat agents as perfectly rational agents and then revise this assumption as appropriate. I argue that such downwards revision is no easy task and that several proposed accounts are not satisfactory. I propose a way of characterising agent's belief states which shares Dennett's approach but avoids treating agents as perfectly rational, and develop a formal account in terms of fan models.

Rule-based and Resource-bounded: A New Look at Epistemic Logic

Syntactic logics do not suffer from the problems of logical omniscience but are often thought to lack interesting properties relating to epistemic notions. By focusing on the case of rule-based agents, I develop a framework for modelling resource-bounded agents and show that the resulting models have a number of interesting properties.

The Sparta and the Athens Of Our Age At Daggers Drawn: Polities, Perceptions, and Peace

While historically notions of democracy have varied widely, democratic peace theory has generally defined it in procedural terms. This article takes a close look at the Anglo-French confrontation of 1840. I show that while leaders on both sides were prepared to risk war to gain bargaining advantages, only the French left really wanted to fight. Why? By today's criteria, Britain was incontestably more democratic, with its monarch's powers far more restricted and its suffrage several times as large. Nevertheless, both sides considered France more democratic, with French republicans despising Britain as an aristocratic oligarchy. While Spencer Weart is right to argue that democratic republics may be hostile to oligarchic ones, they will not necessarily define each other according to modern procedural criteria. Instead, they may judge regimes by the broader social structures that shape power relationships and by outcomes, possibly explaining wars or near misses between democracies.

Existence and wandering of bumps in a spiking neural network model

We study spatially localized states of a spiking neuronal network populated by a pulse coupled phase oscillator known as the lighthouse model. We show that in the limit of slow synaptic interactions in the continuum limit the dynamics reduce to those of the standard Amari model. For non-slow synaptic connections we are able to go beyond the standard firing rate analysis of localized solutions allowing us to explicitly construct a family of co-existing one-bump solutions, and then track bump width and firing pattern as a function of system parameters. We also present an analysis of the model on a discrete lattice. We show that multiple width bump states can co-exist and uncover a mechanism for bump wandering linked to the speed of synaptic processing. Moreover, beyond a wandering transition point we show that the bump undergoes an effective random walk with a diffusion coefficient that scales exponentially with the rate of synaptic processing and linearly with the lattice spacing.

The code document's structure and analysis

The purpose of this paper is twofold. Firstly it presents a preliminary and ethnomethodologically-informed analysis of the way in which the growing structure of a particular program's code was ongoingly derived from its earliest stages. This was motivated by an interest in how the detailed structure of completed program `emerged from nothing' as a product of the concrete practices of the programmer within the framework afforded by the language. The analysis is broken down into three sections that discuss: the beginnings of the program's structure; the incremental development of structure; and finally the code productions that constitute the structure and the importance of the programmer's stock of knowledge. The discussion attempts to understand and describe the emerging structure of code rather than focus on generating `requirements' for supporting the production of that structure. Due to time and space constraints, however, only a relatively cursory examination of these features was possible. Secondly the paper presents some thoughts on the difficulties associated with the analytic---in particular ethnographic---study of code, drawing on general problems as well as issues arising from the difficulties and failings encountered as part of the analysis presented in the first section.

A Wel(l)come development: research funders and open access

This paper discusses the implications of the Wellcome Trust agreement with Blackwell, OUP and Springer in which authors of accepted papers are able to pay an open-access publication charge to make their article freely available online. In bringing together flexible licence terms and clear funding streams, the agreement has the potential to be used as a way of migrating towards possible new business models for journal publishing. It also has the potential, if implemented more widely, to deliver greater open access in such a way as to work in the interests of a broad range of stakeholders.

Rumours, Bargains and Lies: How to advocate Open Access repositories more successfully

In this workshop seminar delivered twice at the CoFHE/UCR 2006 conference the author explored aspects relating to successful advocacy of Open Access and repositories. Areas covered included preconceptions on the part of academics and support staff, as well as models of implementation of an advocacy programme. A large portion of the material pulls together experience and narrative evidence from the SHERPA Consortium partners and repository administrators; with a particular focus on their successes and failures and the lessons that have been learned.