Solving subclasses of multi-player stochastic games via linear complementarity problem formulations—a survey and some new results

We briefly survey some results on the orderfield property of 2-player and multi-player stochastic games and their mixtures. Some of these classes of stochastic games can be solved by formulating them as a Linear Complementarity Problem (LCP) or (Generalized) Vertical Linear Complementarity Problem (VLCP). We discuss some of these results and prove that certain new subclasses and mixtures of multi-player (or n-person) stochastic games can be solved via LCP formulations. Mohan, Neogy and Parthasarathy (in Proceedings of the International Conference on Complementarity Problems, 1997) proposed an LCP formulation of ??-discounted (multi-player) polystochastic games where the transitions are controlled by one player, and proved that this LCP is processible by Lemke??s algorithm. Using this formulation repeatedly, we prove that we can solve a subclass of ??-discounted switching control polystochastic games. As our proof is constructive, we have an algorithm for solving this subclass. This algorithm only involves iteratively solving different LCPs and hence, it follows that this subclass has the orderfield property, a?question left open in the paper on orderfield property of mixtures of stochastic games by Krishnamurthy et al., (Indian J. Stat. 72:246?C275, 2010). Furthermore, we use results from Krishnamurthy et al., Indian J. Stat. 72:246?C275, (2010) to solve some mixture classes using LCP (or VLCP) formulations. We also propose two different VLCP formulations for ??-discounted zero-sum perfect information stochastic games, the underlying matrices of both formulations being R ₀. As a result, we also have an alternative proof of the orderfield property of such games.     

Electroabsorption enhancement in tensile strained quantum wells viaabsorption edge merging

Electroabsorption in quantum wells under biaxial tension is investigated theoretically. It is found that enhanced electroabsorption due to a field-induced merging of the light and heavy hole absorption edges can be achieved in these structures at moderate operating fields. Calculations showing this merging and electroabsorption enhancement for In_xGa_1-xAs-InP and GaAs_xP_1-x-Al_0.35Ga_0.65As quantum well structures are described. Trade-offs involving the advantages of merged absorption edges are identified through comparisons of tensile strained modulators utilizing the merging effect of analogous lattice matched structures. Optimal structures for operation at 1.55 μm in In_xGa_1-xAs-InP and 0.77 μm in GaAs_xP_1-x-Al_0.35Ga_0.65As are identified, and the sensitivities of their electroabsorption characteristics to material and structural parameters are examined     

The distributed feedback waveguide modulator

A novel waveguide electroabsorption modulator structure is proposed. In this structure, the resonator properties of a quarter-wave phase-shifted grating are combined with the electroabsorption properties of a multiple-quantum-well (MQW) waveguide. The theory and design considerations for such a distributed feedback MQW modulator are discussed. The performance characteristics of this structure are studied theoretically and compared with conventional MQW waveguide modulators. It is found that increased modulation bandwidth and reasonable optical bandwidths can be obtained over a device without feedback, and design tradeoffs are identified and explored     

Assessing the effect of processing variables on the mechanical response of polysytrene molded using vibration‐assisted injection molding process

The present work is focused on the study of vibration‐assisted injection molding (VAIM) process, using polystyrene as a model polymeric system. This recently developed polymer processing operation is based on the concept of using motion of the injection screw to apply mechanical vibration to polymer melt during the injection and packing stages of injection molding process, to control the polymer behavior at a molecular level, which would result in improvements/alterations to the mechanical behavior of molded products. In this study, the afore‐mentioned concept was verified experimentally from monotonic tensile experiments and birefringence measurements of VAIM molded polystyrene in comparison with those of conventional injection molding process. The results of our study indicate that the actual degree of strength improvement depends on at least four parameters, namely, vibration frequency, vibration amplitude, vibration duration, and the delay time between the injection start and the vibration start. Furthermore, when these parameters were optimized, as much as a 28% strength improvement was observed, accompanied by an increase in toughness. Furthermore, birefringence measurements revealed that VAIM processing significantly altered the residual stress distribution throughout final products, but it did not, however, change the material density in the products. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Theory of hot carrier effects on nonlinear gain in GaAs-GaAlAslasers and amplifiers

A concise and straightforward model of nonlinear grain based on the carrier heating effect in semiconductor lasers is presented. The problem is formulated using the density matrix approach and includes a priori the effect of free-carrier absorption. Coupled field-medium equations involving photon densities, carrier densities, and carrier temperatures are derived using the results of the density matrix method. The propagation of ultrashort pulses in laser amplifiers is studied and a qualitatively new model along with results on the transient gain recovery dynamics are presented. The model accounts for the wavelength dependence of the asymmetric part of the nonlinear gain observed in direct mixing experiments observed in semiconductor lasers