9793653
Paradoxical Relationship between Output and Input Regularity for the FitzHugh-Nagumo Model
We examine the effects of changing the coefficient of variation (CV) of the inter-stimulus interval on the CV of the output interspike interval (ISI), using constant magnitude, supra-threshold point-process stimuli of the membrane potential variable in the FitzHugh-Nagumo model. The coefficient of variation of the input is changed within the context of a displaced exponential distribution. We find that for some values of mean inter-stimulus interval, CV of ISI has an inverse relationship with input coefficient of variation, whereas for other mean stimulation rates, CV of ISI increases with input coefficient of variation. Over a wide range of input regularity CV of ISI is approximately constant, and is less than 0.4.
26554848
What is observable in a class of neurodynamics?
652273
Decoding Input Signals in Time Domain—A Model Approach
From an observation of efferent interspike intervals of a neuron, we consider how to decode the input temporal information. It is found that the integrate-and-fire model is blind in the temporal domain due to the fact that its efferent firing rate is independent of the input temporal frequency. The conclusion is then confirmed for the integrate-and-fire model with correlated inputs, with reversal potentials, with a nonlinear leakage and with a subthreshold oscillation. For the Hodgkin-Huxley model, however, in terms of efferent firing rates alone, it is possible to read out the input temporal information.
206848726
Viewing a Class of Neurodynamics on Parameter Space
Nearly all models in neural networks start from the assumption that the input-output characteristic is a sigmoidal function. On parameter space we present a systematic and feasible method for analyzing the whole spectrum of attractors-all saturated, all-but-one saturated, all-but-two saturated, etc. — of a neurodynamical system with a saturated sigmoidal function as its input-output characteristic. We present an argument which claims, under a mild condition, that only all saturated or all-but-one saturated attractors are observable for the neurodynamics. For any given all saturated configuration ξ (all-but-one saturated configuration η) the paper shows how to construct an exact parameter region R(ξ) (¯R(η)) such that if and only if the parameters fall within R(ξ) (¯R(η)), then ξ (η) is an attractor (a fixed point) of the dynamics. The parameter region for an all saturated fixed point attractor is independent of the specific choice of a saturated sigmoidal function, whereas for an all-but-one saturated fixed point it is sensitive to the input-output characteristic.
42776203
Fixed-Point Attractor Analysis for a Class of Neurodynamics
Nearly all models in neural networks start from the assumption that the input-output characteristic is a sigmoidal function. On parameter space, we present a systematic and feasible method for analyzing the whole spectrum of attractorsall-saturated, all-but-one-saturated, all-but-twosaturated, and so onof a neurodynamical system with a saturated sigmoidal function as its input-output characteristic. We present an argument that claims, under a mild condition, that only all-saturated or all but-one-saturated attractors are observable for the neurodynamics. For any given all-saturated configuration (all-but-one-saturated configuration ) the article shows how to construct an exact parameter region R()(()) such that if and only if the parameters fall within R()(()), then () is an attractor (a fixed point) of the dynamics. The parameter region for an all-saturated fixed-point attractor is independent of the specific choice of a saturated sigmoidal function, whereas for an all-but-one-saturated fixed point, it is sensitive to the input-output characteristic. Based on a similar idea, the role of weight normalization realized by a saturated sigmoidal function in competitive learning is discussed. A necessary and sufficient condition is provided to distinguish two kinds of competitive learning: stable competitive learning with the weight vectors representing extremes of input space and being fixed-point attractors, and unstable competitive learning. We apply our results to Linsker's model and (using extreme value theory in statistics) the Hopfield model and obtain some novel results on these two models.
39095130
Output jitter diverges to infinity, converges to zero or remains constant
27826765
Analysing Flight Data Using Clustering Methods
This paper reviews existing forms of density-based, partitional and hierarchical clustering methods in the context of flight data analysis. Advantages and disadvantages are fully explored with a focus on proposing a clustering-based ensemble framework for monitoring flight data in order to search for anomalies during flight operation. Case studies in selected flight scenarios are provided to demonstrate the potential of clustering methods and their integration with reasoning techniques in detecting abnormal flights.
36256315
Visual-Based View-Invariant Human Motion Analysis: A Review
This paper provides a comprehensive survey of research on view-invariant human motion analysis. Recent research has shown that view-invariant related issues has been one of the bottlenecks for human motion understanding. The priority in this paper has been given to view-invariant pose representation and estimation, behaviour understanding. Research challenges and future directions are discussed in the end.
42606216
Wiring the academy (panel session): what's working, what's not, what's next, and why
The network era of computing is and will profoundly change the conduct of management education. It offers opportunities for building new types of learning relationships among faculty, departments, colleges, students, and the corporations who employ business graduates. The challenges of funding and leading organizational change at the academy to seize these opportunities, however, are quite daunting. While successes with particular courses, student groups, or executive education programs abound, few business schools have succeeded with large scale IT implementation and the cultural changes necessary to thrive and lead in the network era of computing. This set of changes is referred to as wiring the academy.
9261429
Understanding user behaviour and its metrics
We are pleased to bring together such a great group of people to speak about various aspects of user behaviour and trends, an important topic for us all. We are sometimes guilty of assuming we know what users want. Those assumptions have been challenged in recent years by sophisticated evidence-based studies, the impact of which has been further heightened by digital systems that are responding to the new and changing needs of researchers operating on the front lines of science. To start the programme, two such scientists will provide accounts of how they respond to the information challenges they face in their respective fields. During the day we will learn about the background motivations for, and situations in which, researchers increasingly operate. The challenge is to interpret what this means in terms of our own organisations. This is a timely issue for the British Library as it revisits its science, technology and medical strategy to meet its own changing needs as well as the needs of new generations of researchers. This will require adaptations to our information and knowledge services and policies, something I suspect applies to all ICSTI members here engaged in service provision. A relevant example of this is the British Library’s recent launch of the UK PubMed Central, a US–UK collaboration with the support of research funding agencies and driven by the Wellcome Trust. We are pleased that representatives of those organisations are here today. Participants from 12 countries are among us, making this a truly international gathering. I am delighted to welcome you all here today.
22693835
The new economy: an engineer's perspective
From his twin perspectives as a career-long telecommunications engineer and Chairman of one of the UK's largest electronics companies, Sir David Brown will reflect on whether and when the New Economy, seemingly so long coming, will finally arrive. He will begin by exploring how the prospect of everything being digital; everyone having broadband; and intelligence being everywhere is changing our understanding of mobility. Then he will comment on the economic effects of that changed understanding under three headings - the macroeconomy, microeconomy and socioeconomy - before suggesting the criteria we might use to decide when the New Economy has arrived.