Connectivity in real and evolved associative memories

Peer reviewe

High capacity associative memory with bipolar and binary, biased patterns

The high capacity associative memory model is interesting due to its significantly higher capacity when compared with the standard Hopfield model. These networks can use either bipolar or binary patterns, which may also be biased. This paper investigates the performance of a high capacity associative memory model trained with biased patterns, using either bipolar or binary representations. Our results indicate that the binary network performs less well under low bias, but better in other situations, compared with the bipolar network.Peer reviewe

Mediating exposure in public interactions

Mobile computing and public interactions together open up a new range of challenges in interaction design. To date a very gregarious model of interaction has been assumed. However, the public setting will invoke feelings of shyness and a desire to control the personal exposure associated with interactions. In this paper we discuss these issues and our initial tests of a system which affords a control beyond "engage or don't engage"

Connection Strategies in Associative Memory Models

“The original publication is available at www.springerlink.com”. Copyright Springer.The problem we address in this paper is that of finding effective and parsimonious patterns of connectivity in sparse associative memories. This problem must be addressed in real neuronal systems, so results in artificial systems could throw light on real systems. We show that there are efficient patterns of connectivity and that these patterns are effective in models with either spiking or non-spiking neurons. This suggests that there may be some underlying general principles governing good connectivity in such networks.Peer reviewe

An environmental model of self-compatibility transitions in the solanaceae plant family

Higher level selection processes such as species selection are not generally predicted to overpower individual selection on character traits. Goldberg et al. provide a model derived from collected life history data and argue that species selection is maintaining self-incompatibility in the Solanaceae plant family. This model applies only on the level of the species, not representing the underlying interactions between individuals and the environment. We propose a new model with environmental variation at the individual level that may explain the maintenance and frequency of loss of this character trait. We use individual based modelling techniques to explore our hypothesis, and compare it with that originally proposed. The results show alternative values required for the mutation rate to produce the species level transition frequency under the opposing models, given certain assumptions. Future work is suggested to refine the parameter relationships, test for robustness, and determine if individual models of higher complexity will exhibit similar outcomes

The beneficial effects of non-specific synaptic plasticity for pattern recognition in auto-associative memory

© 2011 Calcraft et al; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Poster presented at CNS 2011Non peer reviewe

Children left at home alone: the construction of a social problem

The question of when a child is old enough to be left at home alone, and under what circumstances, is a dilemma faced by many parents and professionals. Adopting a social constructionist perspective of social problems, this thesis explores professional perceptions and policy responses to the issue of children left at home alone since the passing of the Children Act in 1989. The law in England and Wales does not specify an age at which it is deemed safe to leave a child unsupervised at home, a practice sometimes referred to as 'self-care'. Professionals respond to the issue through non-legalistic, more persuasive interventions. The media also plays a role in regulating parenting practices, as demonstrated in the early 1990s, when the British press covered a number of stories involving parents who left their children at 'home alone'. The issue continues to bubble up from time to time, but calls for more specific law to manage the problem have gone unheeded. Drawing on interviews with child welfare professionals and campaigners who work at national level, and on an analysis of policy, campaigning and educational documents, I explore how the issue is constructed, responded to and resisted as a social problem. I conclude that this is an example of an 'unconstructed' social problem because, despite continued public and professional concern, there has been no clear legislative response. Understanding how and why some social problems 'fail' is a key contribution to the literature on the social construction of social problems, which has focused mainly on 'successful' social problems to date

Children left at home alone: the construction of a social problem

The question of when a child is old enough to be left at home alone, and under what circumstances, is a dilemma faced by many parents and professionals. Adopting a social constructionist perspective of social problems, this thesis explores professional perceptions and policy responses to the issue of children left at home alone since the passing of the Children Act in 1989. The law in England and Wales does not specify an age at which it is deemed safe to leave a child unsupervised at home, a practice sometimes referred to as 'self-care'. Professionals respond to the issue through non-legalistic, more persuasive interventions. The media also plays a role in regulating parenting practices, as demonstrated in the early 1990s, when the British press covered a number of stories involving parents who left their children at 'home alone'. The issue continues to bubble up from time to time, but calls for more specific law to manage the problem have gone unheeded. Drawing on interviews with child welfare professionals and campaigners who work at national level, and on an analysis of policy, campaigning and educational documents, I explore how the issue is constructed, responded to and resisted as a social problem. I conclude that this is an example of an 'unconstructed' social problem because, despite continued public and professional concern, there has been no clear legislative response. Understanding how and why some social problems 'fail' is a key contribution to the literature on the social construction of social problems, which has focused mainly on 'successful' social problems to date