32,298 research outputs found
Simulation of networks of spiking neurons: A review of tools and strategies
We review different aspects of the simulation of spiking neural networks. We
start by reviewing the different types of simulation strategies and algorithms
that are currently implemented. We next review the precision of those
simulation strategies, in particular in cases where plasticity depends on the
exact timing of the spikes. We overview different simulators and simulation
environments presently available (restricted to those freely available, open
source and documented). For each simulation tool, its advantages and pitfalls
are reviewed, with an aim to allow the reader to identify which simulator is
appropriate for a given task. Finally, we provide a series of benchmark
simulations of different types of networks of spiking neurons, including
Hodgkin-Huxley type, integrate-and-fire models, interacting with current-based
or conductance-based synapses, using clock-driven or event-driven integration
strategies. The same set of models are implemented on the different simulators,
and the codes are made available. The ultimate goal of this review is to
provide a resource to facilitate identifying the appropriate integration
strategy and simulation tool to use for a given modeling problem related to
spiking neural networks.Comment: 49 pages, 24 figures, 1 table; review article, Journal of
Computational Neuroscience, in press (2007
Integration, Cooperation and the Financing of Innovation
The purpose of this paper is to develop a joint analysis of the organizational and financial flexibility of the innovative firm. In this way, we complete by determinants linked to financing factors the choice between integration and inter-firms co-operative agreements. We deduce the superiority of co-operation to resolve the specialization-adaptability dilemma which faced the innovative firm.financing, innovation, integration, cooperation
Base and surge strategies for controlling environmental and economic costs in logistics triads
The aim of this paper is to determine the extent to which it is possible to establish a âbaseâ and âsurgeâ strategy for logistics provision with a particular emphasis on minimising environmental and economic costs. Our method is the combination of empirical research outputs on the impact of uncertainty on economic and environmental costs, and a synthesis of the literature on resilience and the role of flexibility therein. We find that logistics planners either build contingents into their schedules (a priori) or that they respond with contingencies (a posteriori). The former is associated with a âbaseâ approach; an example of which may be the incorporation of âslack timeâ into a schedule to accommodate expected delays due to road congestion. The latter is equivalent to a âsurgeâ approach where as an example the logistics provider may have capacity flexibility, in the form of spare vehicles, to accommodate post-plan changes in shipper volume requirements. This paper explicitly rationalises the links between uncertainty, âbaseâ and âsurgeâ supply chain strategies, and the strategic use of logistics flexibility, in minimising environmental and economic costs in a logistics triad. The output is in the form of a conceptual managerial feedback control system
- âŠ