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Sridhar, R.

Publications and source records attributed to Sridhar, R..

12 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

Extremes of Survival Achieved by the Radiophile Deinococcus Radiodurans: A Model for Microbial Life on Mars

Deinococcus radiodurans is an extremophile in more than one defined way. First it is extreme in its resistance to freeze drying. Second it is probably uniquely extreme on Earth in its resistance to ionizing radiation. The polyextremophilic capacity of D. radiodurans will be considered. The selection pressures on Mars will then be considered in relation to D. radiodurans in order to support a hypothesis that if microbial life exists on Mars, then it likely includes polyextremophiles.

Daly, M.↗
NASA NTRS1972

Minimum-energy control of a class of electrically driven vehicles.

A minimum-energy controller is designed and built for a class of electrically driven vehicles according to the theoretical concepts determined by the application of modern control theory. Theoretical results are obtained by making several justifiable assumptions in the dynamical equations of the system and solving the resulting stochastic optimal control problem by Bellman's dynamic programming technique. Several practical and economical considerations are taken into account for the mechanization of the minimum-energy control law.

Sahinkaya, Y. E.↗
NASA NTRS1971

Analytical methods for performance evaluation of nonlinear filters.

In the investigation, the filtering problem is considered in the continuous time domain. The postulated simple suboptimal nonlinear filter structure closely parallels the structure of the Kalman-Bucy optimal linear filter algorithm. Two filter performance evaluation methods are developed based on the Kolmogorov equations for the transition density of Markov processes. The expansions in the approximations for the nonlinear system and observation functions are in effect carried out up to second-order terms in both methods. The description of the filter's performance is sought in terms of second-order statistics in both methods.

Bejczy, A. K.↗