Memristor Neural Network Design

Neural network, a powerful learning model, has archived amazing results. However, the current Von Neumann computing system–based implementations of neural networks are suffering from memory wall and communication bottleneck problems ascribing to the Complementary Metal Oxide Semiconductor (CMOS) technology scaling down and communication gap. Memristor, a two terminal nanosolid state nonvolatile resistive switching, can provide energy‐efficient neuromorphic computing with its synaptic behavior. Crossbar architecture can be used to perform neural computations because of its high density and parallel computation. Thus, neural networks based on memristor crossbar will perform better in real world applications. In this chapter, the design of different neural network architectures based on memristor is introduced, including spiking neural networks, multilayer neural networks, convolution neural networks, and recurrent neural networks. And the brief introduction, the architecture, the computing circuits, and the training algorithm of each kind of neural networks are presented by instances. The potential applications and the prospects of memristor‐based neural network system are discussed

Experimental investigation of effects of ullage height on the burning rate and heat feedback in pool fires

Pool fire with varying ullage height is a common type of accident that occurs in industrial parks. This paper explores the ullage height effects on the burning rate and heat feedback in pool fires through the experimental and theoretical study. A series of experiments were conducted using heptane with four tray sizes and five ullage heights. The results show that, the burning rate initially decreases, then increases and finally decreases as the ullage height increases. These results are mainly dependent on the change of internal flame behavior and thus heat feedback mechanisms with increasing ullage height. In the small ullage height conditions, the convective heat feedback reduces substantially whereas the radiative one rises slightly. When the ullage height reaches to a certain value, the convective heat feedback suddenly increases because of the flame inside the tray. The radiative heat feedback decreases gradually as the ullage height increase continually, while the convective one becomes nearly constant. Based on these results, three regimes are identified in terms of the burning rate variation with heat feedback: (1) convection controlled, (2) convection-radiation controlled and (3) radiation controlled. The new controlling mechanism of the burning rate variation (with ullage height), as a further extension of the classic scaling model by Blinov and Khudyakov on the burning rate variation (with pool diameter), could lay a solid foundation for future studies of the other key parameters in tank fires

Equilibrium price and optimal insider trading strategy under stochastic liquidity with long memory

In this paper, the Kyle model of insider trading is extended by characterizing the trading volume with long memory and allowing the noise trading volatility to follow a general stochastic process. Under this newly revised model, the equilibrium conditions are determined, with which the optimal insider trading strategy, price impact and price volatility are obtained explicitly. The volatility of the price volatility appears excessive, which is a result of the fact that a more aggressive trading strategy is chosen by the insider when uninformed volume is higher. The optimal trading strategy turns out to possess the property of long memory, and the price impact is also affected by the fractional noise.Comment: 21 pages; 2 figure

Experimental study on flame length and pulsation behavior of n-heptane continuous spill fires on water

Continuous spill fires pose significant risks to the storage and transportation industries of liquid fuels. To investigate the flame length and pulsation behavior of continuous spill fires, large-scale spill fire experiments were conducted on water to simulate the burning fuel on a water surface that could occur during firefighting of tank fires or due to leaked fuels on water during transportation, with varying discharge rates (3, 6, 9, 14 mL/s) and ignition delays (0, 10, 20, 30 s). The results suggest that the flame length increased initially with the spread area and reached the maximum at the end of the spreading stage, then followed by a decrease at the shrinking stage and kept nearly constant at the steady stage. For the steady flame length, a new correlation  ( ⁄ =3.1(∗)0.42)  was established based on dimensionless analysis, which was higher than that for pool fires, highlighting the important differences between spill and pool fires. This developed model was also used to predict the maximum flame length with a maximum deviation of 19.2%, as the heat transfer mechanism and air entrainment are expected to be similar at the shrinking and steady stages. The flame pulsation frequency was determined through the fast Fourier transform (FFT) method, which shows a gradual decrease during the spreading stage while remaining higher than that of pool fires at the steady stage. Subsequently, two new correlations ns (=0.525√ ⁄  and =0.724√ ⁄ ) were derived from experimental data to predict the pulsation frequency at both spreading and steady stages. The higher frequencies during the steady stage can have a significant influence on the radiation impact to adjacent equipment or personnel. This study not only provides insights into the flame and pulsation behaviors of spill fires but lays a solid foundation for the thermal hazard and risk assessment analysis in the liquid fuel storage and transportation industries