http://www.pyoudeyer.com/TICSCuriosity2013.pdf

Information-seeking, curiosity, and attention: computational and neural mechanisms

Attention allows us to select relevant sensory information for preferential processing. Behaviourally, it improves performance in various visual tasks. One prominent effect of attention is the modulation of performance in tasks that involve the visual system's spatial resolution. Physiologically, attention modulates neuronal responses and alters the profile and position of receptive fields near the attended location. Here, we develop a hypothesis linking the behavioural and electrophysiological evidence. The proposed framework seeks to explain how these receptive field changes enhance the visual system's effective spatial resolution and how the same mechanisms may also underlie attentional effects on the representation of spatial information.

/pdf/attentional-enhancement-of-spatial-resolution-linking-4dg5zbeezs.pdf

Attentional enhancement of spatial resolution: linking behavioural and neurophysiological evidence

In natural behaviour, animals actively interrogate their environments using endogenously generated 'question-and-answer' strategies. However, in laboratory settings participants typically engage with externally imposed stimuli and tasks, and the mechanisms of active sampling remain poorly understood. We review a nascent neuroscientific literature that examines active-sampling policies and their relation to attention and curiosity. We distinguish between information sampling, in which organisms reduce uncertainty relevant to a familiar task, and information search, in which they investigate in an open-ended fashion to discover new tasks. We review evidence that both sampling and search depend on individual preferences over cognitive states, including attitudes towards uncertainty, learning progress and types of information. We propose that, although these preferences are non-instrumental and can on occasion interfere with external goals, they are important heuristics that allow organisms to cope with the high complexity of both sampling and search, and generate curiosity-driven investigations in large, open environments in which rewards are sparse and ex ante unknown.

Towards a neuroscience of active sampling and curiosity.

Attention, Learning, and the Value of Information

Gaze Control as Prediction.

Visualization of unsteady viscous flow around turbine blade

A semiconductor switching apparatus includes a member for radiating heat generated from semiconductor switching element chips and for reducing a thermal stress. The lengths of gate electrode wires are equally set. The semiconductor switching apparatus has a large capacity and good switching characteristics.

Power semiconductor switching apparatus with heat sinks

The cooling performance of compact heat sinks composed of small fins, investigated in conditions of both natural and forced air convection, should also be explored in designing the heat sink on an LSI package. An experimental study was performed with respect to natural air convection and forced air convection. Several kinds of compact heat sink which have different base areas, fin intervals and fin heights were heated by an attached electrical heater, which could supply a specific heat flux. The increase in fin temperature was measured by small thermocouples. In natural air convection experiments, the effect of the supplied wattage on the temperature rise of the heat sink was examined for different fin intervals and fin heights. In forced air convection experiments, a wind tunnel was used. The heat sink was set downstream in the wind tunnel and a specific heat flux was applied to it. The correlation between supplied air velocity and temperature rise in the heat sinks was explored. Furthermore, fro...

Experimental study on the performance of a compact heat sink for LSI packages

In the present study, the robust thermal design of a power device package was accomplished using thermal conduction calculation, design of experiment, response surface method and Monte Carlo simulation. Initially, the effects of the design parameters on the solder strain were examined in terms of the thermal expansion difference as a result of unsteady thermal conduction simulation. From the factorial effects of design parameters, the design proposals were screened. Then, robustness of the thermal resistance was evaluated for the three design proposals obtained. The thermal resistances were calculated by solving the steady thermal conduction equation under the design of experiment conditions. The solder thickness, the substrate thickness, and the cooling fin performance were considered as the fluctuation factors, assuming the error associated with manufacturing process. Using a response surface method, the values of thermal resistance were expressed as a function of the design variables. The variances of the thermal resistance were examined based on Monte Carlo simulations. Related to the cooling fin design, the Pareto line showing the trade-off relation between the fin dimension and the fan velocity was obtained. By repeating the Monte Carlo simulations, the Pareto solution was calculated so that the thermal resistances satisfy the criteria in the position of 95 percrntile of the thermal resistance variation. Under the same flow velocity conditions, the fin dimensions become about 10% higher compared to the case where the manufacturing error was not taken into account. By carrying out the thermal design following this Pareto line, even if the manufacturing error was taken into consideration, the thermal resistance could satisfy the desired value.Copyright © 2007 by ASME

Robust Thermal Design for Power Device Package Using Response Surface Method and Monte Carlo Simulation

In the present study, the robust thermal design of a power device package was accomplished using thermal conduction calculation, design of experiment, response surface method and Monte Carlo simulation. Initially, the effects of the design parameters on the solder strain were examined in terms of the thermal expansion difference as a result of unsteady thermal conduction simulation. From the factorial effects of design parameters, the design proposals were screened. Then, robustness of the thermal resistance was evaluated for the three design proposals obtained. The thermal resistances were calculated by solving the steady thermal conduction equation under the design of experiment conditions. The solder thickness, the substrate thickness, and the cooling fin performance were considered as the fluctuation factors, assuming the error associated with manufacturing process. Using a response surface method, the values of thermal resistance were expressed as a function of the design variables. The variances of the thermal resistance were examined based on Monte Carlo simulations. Related to the cooling fin design, the Pareto line showing the trade-off relation between the fin dimension and the fan velocity was obtained. By repeating the Monte Carlo simulations, the Pareto solution was calculated so that the thermal resistances satisfy the criteria in the position of 95 percentile of the thermal resistance variation. Under the same flow velocity conditions, the fin dimensions become about 10% higher compared to the case where the manufacturing error was not taken into account. By carrying out the thermal design following this Pareto line, even if the manufacturing error was taken into consideration, the thermal resistance could satisfy the desired value.

Yasuyuki Yokono

Papers

Visualization of unsteady viscous flow around turbine blade

Power semiconductor switching apparatus with heat sinks

Experimental study on the performance of a compact heat sink for LSI packages

Robust Thermal Design for Power Device Package Using Response Surface Method and Monte Carlo Simulation

Robust Thermal Design for Power Device Package Using Response Surface Method and Monte Carlo Simulation