A transition-encoded dynamic bus technique for high-performance interconnects

This paper describes a transition-encoded dynamic bus technique that enables on-chip interconnect delay reduction while maintaining the robustness and switching energy behavior of a static bus. Efficient circuits, designed for a drop-in replacement, enable significant delay and peak-current reduction even for short-length buses, while obtaining energy savings at aggressive delay targets. On a 180-nm 32-bit microprocessor, 79% of all global buses exhibit 10%-35% performance improvement using this technique.     

Reflection of electromagnetic waves from oscillating surfaces

The problem of reflection of electromagnetic waves from oscillating surfaces is discussed. Using the induction theorem, the interface is replaced by equivalent current sources that radiate into an unbounded medium. Spatial movement is ascribed to these sources to account for oscillations of the surface. The general solution for the far-field due to any arbitrary surface motion is developed. A few deterministic and random functions for surface motion are considered. Most of the initial discussion pertains to normal reflection from planar surfaces, but the solution is also obtained for arbitrary incidence and for an oscillating cylinder.     

Ergodic control problem for one-dimensional diffusions with near-monotone cost

The existence and uniqueness of the solution to the Bellman equation for ergodic control of one-dimensional diffusions is established under a ‘near-monotonicity’ condition on the cost. Necessary and sufficient conditions for the optimality of a stable Markov control are given in terms of the same.     

Mathematical Programming Embeddings of Logic

Can theorem proving in mathematical logic be addressed by classical mathematical techniques like the calculus of variations? The answer is surprisingly in the affirmative, and this approach has yielded rich dividends from the dual perspective of better understanding of the mathematical structure of deduction and in improving the efficiency of algorithms for deductive reasoning. Most of these results have been for the case of propositional and probabilistic logics. In the case of predicate logic, there have been successes in adapting mathematical programming schemes to realize new algorithms for theorem proving using partial instantiation techniques. A structural understanding of mathematical programming embeddings of predicate logic would require tools from topology because of the need to deal with infinite-dimensional embeddings. This paper describes the first steps in this direction. General compactness theorems are proved for the embeddings, and some specialized results are obtained in the case of Horn logic.     

Stochastic approximation with ‘controlled Markov’ noise

Stochastic approximation algorithms with additional noise that can be modelled as a controlled Markov process are analyzed and shown to track the solutions of a differential inclusion defined in terms of the ergodic occupation measures associated with the controlled Markov process.     

Synthesis of n‐butyl acetamide over immobilized lipase

BACKGROUND: The conversion of carboxylic esters to amides can be accomplished efficiently by enzymatic catalysis. Amidation of benzyl acetate with n‐butyl amine was studied in non‐aqueous media using immobilized lipases. RESULTS: The activities of immobilized lipases, Novozym 435, Lipozyme RM IM and Lipozyme TL IM were evaluated in the synthesis of n‐butyl acetamide, among which Novozym 435 was the best. The process was optimized by studying various process parameters. Benzyl acetate conversion of 46% was achieved in 8 h for a mole ratio of 3:1 of n‐butyl amine to benzyl acetate with 3.67 g L^?1 Novozym 435 in toluene at 55 °C. A model based on an ordered bi–bi mechanism fitted the initial rate data very well and the rate constant and inhibition constants were calculated by non‐linear regression analysis. The initial rate studies showed that the Michaelis constant for benzyl acetate was low indicating high affinity between the enzyme and the reactant. CONCLUSION: A novel, efficient and environmentally benign enzymatic process is reported for the synthesis of n‐butyl acetamide. This method is general and can be used to synthesize analogous compounds in optically enriched form, since it is difficult to make such amides directly from carboxylic acids and amines by purely chemical means. The theoretical predictions and experimental data matched very well. Copyright © 2008 Society of Chemical Industry     

Accurate on-chip interconnect evaluation: a time-domain technique

This paper describes an on-chip sampling and measurement technique for accurate (<15 ps) evaluation of interconnect delays and coupled noise. We have used this nonintrusive time-domain technique to extract in situ driver/receiver waveforms, propagation delays, and coupled noise in 120 interconnect structures. The effects studied include multiple AC returns through active devices, gridded planes on adjacent layers, via impedances, variable driver impedances, and noise in bus structures. The results provide a comprehensive evaluation of interconnect delays and noise in a 1.8 V, 0.25 μm process     

A sensitivity formula for risk-sensitive cost and the actor–critic algorithm

We propose for risk sensitive control of finite Markov chains a counterpart of the popular ‘actor–critic’ algorithm for classical Markov decision processes. The algorithm is based on a ‘sensitivity formula’ for the risk sensitive cost and is shown to converge with probability one to the desired solution. The proof technique is an adaptation of the ordinary differential equations approach for the analysis of two time-scale stochastic approximation algorithms.