Mode dispersion and delay characteristics of optical waveguides using equivalent TL circuits

A new analysis leading to an exact and efficient algorithm is presented for calculating directly and without numerical differentiation the mode dispersion characteristics of cylindrical dielectric waveguides of arbitrary refractive-index profile. The new algorithm is based on the equivalent transmission-line (T-L) technique. From Maxwell's equations, we derive an equivalent T-L circuit for a cylindrical dielectric waveguide. Based on the TL-circuit model we derive exact analytic formulas for a recursive algorithm which allows direct calculation of mode delay and dispersion. We demonstrate this technique by calculating the fundamental mode dispersion for step, triangular, and linear chirp optical fiber refractive index profiles. The accuracy of the numerical results is also examined. The proposed algorithm computes dispersion directly from the propagation constant without the need for curve fitting and subsequent successive numerical differentiation. It is exact, rapidly convergent, and it results in savings for both storage memory and computing time

Very Deep Convolutional Neural Networks for Robust Speech Recognition

This paper describes the extension and optimization of our previous work on very deep convolutional neural networks (CNNs) for effective recognition of noisy speech in the Aurora 4 task. The appropriate number of convolutional layers, the sizes of the filters, pooling operations and input feature maps are all modified: the filter and pooling sizes are reduced and dimensions of input feature maps are extended to allow adding more convolutional layers. Furthermore appropriate input padding and input feature map selection strategies are developed. In addition, an adaptation framework using joint training of very deep CNN with auxiliary features i-vector and fMLLR features is developed. These modifications give substantial word error rate reductions over the standard CNN used as baseline. Finally the very deep CNN is combined with an LSTM-RNN acoustic model and it is shown that state-level weighted log likelihood score combination in a joint acoustic model decoding scheme is very effective. On the Aurora 4 task, the very deep CNN achieves a WER of 8.81%, further 7.99% with auxiliary feature joint training, and 7.09% with LSTM-RNN joint decoding.Comment: accepted by SLT 201

Relative Entropy: Free Energy Associated with Equilibrium Fluctuations and Nonequilibrium Deviations

Using a one-dimensional macromolecule in aqueous solution as an illustration, we demonstrate that the relative entropy from information theory, $\sum_k p_k\ln(p_k/p_k^*)$, has a natural role in the energetics of equilibrium and nonequilibrium conformational fluctuations of the single molecule. It is identified as the free energy difference associated with a fluctuating density in equilibrium, and is associated with the distribution deviate from the equilibrium in nonequilibrium relaxation. This result can be generalized to any other isothermal macromolecular systems using the mathematical theories of large deviations and Markov processes, and at the same time provides the well-known mathematical results with an interesting physical interpretations.Comment: 5 page

Privatization, concentration, and pressure for protection : a steel sector study

In considering whether to privatize a large state-owned steel enterprise in Argentina, the question arose: Would its sale to a consortium of large domestic enterprises, and the resulting increase in firm concentration, inevitably lead to cries for protection? To shed light on the question, the authors examine data for steel industries in the major industrial countries. They also construct a simulation of Argentina's steel sector to study the relationships between levels of industrial concentration, substitutability between domestic and imported steels, trade policy regimes, and mark-ups of domestic prices over international prices. Their simulation results show that heavier rents and economic distortions are generated through fixed-ratio import quotas (quotas that are a fixed proportion of domestic sales) than through use of a tariff or a fixed-quantity import quota. The results show why industries seeking protection prefer a fixed-ratio import restraint - a practice being used increasingly often in industrial countries. If there is not perfect substitutability between domestic and imported steels, the incentives for the Argentine industry to seek protection - particularly as a fixed-ratio quota - are greater, the more concentrated the industry is. The lesson for policymakers - who should be trying to minimize economic distortions - is that if protection is necessary, tariffs are preferable to import quotas, perhaps even to the point of making quota-type restrictions unconstitutional. The simulation results for Argentina confirm that the less substitutable domestic and foreign goods are, the higher the rents of domestic industry can extract. So, it is important for policymakers implementing privatization schemes to ease any explicit or implicit obstacles to imports by such measures as: (a) standardizing domestic product classifications with international classifications; (b) modernizing transportation facilities to improve the speed of shipment and communication; (c) reducing bureaucratic practices related to trade in goods and services; and (d) releasing foreign exchange restrictions. The goal should be to make a foreign transaction as easy as a domestic transaction.TF054105-DONOR FUNDED OPERATION ADMINISTRATION FEE INCOME AND EXPENSE ACCOUNT,Markets and Market Access,Access to Markets,Environmental Economics&Policies,Economic Theory&Research