A further remark on dynamic programming for partially observed markov processes

In (Stochastic Process. Appl. 103 (2003) 293), a pair of dynamic programming inequalities were derived for the 'separated'ergodic control problem for partially observed Markov processes, using the 'vanishing discount'argument. In this note, we strengthen these results to derive a single dynamic programming equation for the same

Risk-sensitive optimal control for Markov decision processes with monotone cost

The existence of an optimal feedback law is established for the risk-sensitive optimal control problem with denumerable state space. The main assumptions imposed are irreducibility and anear monotonicity condition on the one-step cost function. A solution can be found constructively using either value iteration or policy iteration under suitable conditions on initial feedback law

Bianchi Type-I Hyperbolic Models with Perfect Fluid and Dark Energy in Bimetric Theory of Gravitation

Three different Bianchi type-I cosmological models as related to perfect fluid, with quintessence and with Chaplygin gas, in bimetric theory of gravitation have been deduced. The perfect fluid model has hyperbolic geometry and all its physical parameters are also hyperbolic in nature and therefore they have been studied from hyperbolic geometric view point. All these models are isotropize and shear-less. Other geometrical and physical behaviors of the models have also been studied. The hyperbolic geometric view point of the models will be helpful to the people who use observational data to search for such type of geometry

Adaptive importance sampling technique for markov chains using stochastic approximation

For a discrete-time finite-state Markov chain, we develop an adaptive importance sampling scheme to estimate the expected total cost before hitting a set of terminal states. This scheme updates the change of measure at every transition using constant or decreasing step-size stochastic approximation. The updates are shown to concentrate asymptotically in a neighborhood of the desired zero-variance estimator. Through simulation experiments on simple Markovian queues, we observe that the proposed technique performs very well in estimating performance measures related to rare events associated with queue lengths exceeding prescribed thresholds. We include performance comparisons of the proposed algorithm with existing adaptive importance sampling algorithms on some examples. We also discuss the extension of the technique to estimate the infinite horizon expected discounted cost and the expected average cost

Evaluation of in vitro antihelmintic activity of leaves of Butea monosperma

The preliminary phytochemical screening was carried out on the crude extracts of the leaves of Butea Monosperma Lam along with ash values and extractive values on the powdered drug. The crude extracts were investigated for their anthelmintic activity against earthworms (Pheretima posthuma), roundworms (Ascardia galli.) and tapeworms (Raillietina spiralis). Three concentrations (25, 50 and 100 mg/mL) of each extract were studied in activity, which involved the determination of time of paralysis and time of death of the worm. Alcohol and ethyl acetate extracts exhibited significant anthelmintic activity at highest concentration of 100 mg/mL. Albendazole in same concentration as those of extracts was included as standard reference and Di-methyl formamide as control. The anthelmintic activity of alcohol and ethyl acetate extracts of leaves of Butea Monosperma has therefore been demonstrated for the first time.Keywords: Anthelmintic Activity, Butea Monosperma, Pheretima Posthuma. Ascardia Galli, Raillietina spiralis, DMF (di-methyl formamide

Existence and Uniqueness Results for Difference Φ-Laplacian Boundary Value Problems

This paper is devoted to study the existence and uniqueness of solutions to nonlinear difference Φ-Laplacian boundary value problems with mixed and Dirichlet boundary conditions

Evaluation of in vitro antihelmintic activity of leaves of Butea monosperma

The preliminary phytochemical screening was carried out on the crude extracts of the leaves of Butea Monosperma Lam along with ash values and extractive values on the powdered drug. The crude extracts were investigated for their anthelmintic activity against earthworms (Pheretima posthuma), roundworms (Ascardia galli.) and tapeworms (Raillietina spiralis). Three concentrations (25, 50 and 100 mg/mL) of each extract were studied in activity, which involved the determination of time of paralysis and time of death of the worm. Alcohol and ethyl acetate extracts exhibited significant anthelmintic activity at highest concentration of 100 mg/mL. Albendazole in same concentration as those of extracts was included as standard reference and Di-methyl formamide as control. The anthelmintic activity of alcohol and ethyl acetate extracts of leaves of Butea Monosperma has therefore been demonstrated for the first time.Keywords: Anthelmintic Activity, Butea Monosperma, Pheretima Posthuma. Ascardia Galli, Raillietina spiralis, DMF (di-methyl formamide