On some strategies using auxiliary information for estimating finite population mean

This paper presents an empirical investigation of the performance of five strategies for estimating the finite population mean using parameters such as mean or variance or both of an auxiliary variable. The criteria used for the choices of these strategies are bias, efficiency and approach to normality (asymmetry)

Effect of formal specifications on program complexity and reliability: An experimental study

The results are presented of an experimental study undertaken to assess the improvement in program quality by using formal specifications. Specifications in the Z notation were developed for a simple but realistic antimissile system. These specifications were then used to develop 2 versions in C by 2 programmers. Another set of 3 versions in Ada were independently developed from informal specifications in English. A comparison of the reliability and complexity of the resulting programs suggests the advantages of using formal specifications in terms of number of errors detected and fault avoidance

Time Dependence of Brans-Dicke Parameter w for an Expanding Universe

We have studied the time dependence of w for an expanding universe in the generalised B-D theory and have obtained its explicit dependence on the nature of matter contained in the universe,in different era.Lastly we discuss how the observed accelerated expansion of the present universe can be accomodated in the formalism.Comment: 10 pages,No figure

The gravity-related decoherence master equation from hybrid dynamics

Canonical coupling between classical and quantum systems cannot result in reversible equations, rather it leads to irreversible master equations. Coupling of quantized non-relativistic matter to gravity is illustrated by a simplistic example. The heuristic derivation yields the theory of gravity-related decoherence proposed longtime ago by Penrose and the author.Comment: 9pp, extended version of invited talk at Fifth International Workshop DICE2010 (Castello Pasquini/Castiglioncello/Tuscany, Sept. 13-17, 2010

Mixing quantum and classical mechanics and uniqueness of Planck's constant

Observables of quantum or classical mechanics form algebras called quantum or classical Hamilton algebras respectively (Grgin E and Petersen A (1974) {\it J Math Phys} {\bf 15} 764\cite{grginpetersen}, Sahoo D (1977) {\it Pramana} {\bf 8} 545\cite{sahoo}). We show that the tensor-product of two quantum Hamilton algebras, each characterized by a different Planck's constant is an algebra of the same type characterized by yet another Planck's constant. The algebraic structure of mixed quantum and classical systems is then analyzed by taking the limit of vanishing Planck's constant in one of the component algebras. This approach provides new insight into failures of various formalisms dealing with mixed quantum-classical systems. It shows that in the interacting mixed quantum-classical description, there can be no back-reaction of the quantum system on the classical. A natural algebraic requirement involving restriction of the tensor product of two quantum Hamilton algebras to their components proves that Planck's constant is unique.Comment: revised version accepted for publication in J.Phys.A:Math.Phy

Uniform Water Distribution From Low Pressure Rotating Sprinklers

Population of India has probably crossed 1150 million marks by the end of 2007 (Survey of Indian Agriculture 2007). The estimated requirement of food grains by 2020 will be 307.75 million tonnes to meet the balanced diet norms prescribed by Indian Council of Medical Research. In 2007, the production of food grains was only 212.62 million tonnes. The gap of 95.13 million tonnes has to be narrowed down by adopting modern scientific approaches for efficient management of scarce land and water resources at a sustainable manner.Sprinkler irrigation is one of the modern scientific approaches which is becoming more and more popular in India in regions of water scarcity where available water is insufficient to irrigate the command area by surface irrigation. Uniformity of water distribution at four different nozzle pressures and three different spacing was studied for both plastic and brass type of sprinklers. The deviation of uniformity coefficient of plastic sprinklers from that of brass sprinklers was found to be from 0 to 2 %. It was also observed that optimum uniformity of water distribution was obtained at a nozzle pressure of 2.0 kgf/cm2 in normal windy condition. The uniformity of water distribution decreased with the increase of nozzle pressure beyond 2.0 kgf/cm2 for small and medium size nozzles.Comparison was made among different sprinklers and lateral spacing of 6.1 m x 6.1 m, 6.1 m x 12.2 m and 12.2 m x 12.2 m. It was observed that the spacing of 6.1 m x 6.1 m gives better distribution for low pressure sprinklers for all combinations of nozzle pressures and sizes. It was recommended to operate the low pressure sprinklers at a sprinkler and lateral spacing of 30 % of the spray diameter. It was also observed that the effect of wind velocity on uniformity of water distribution was less for wind velocities below 4 km/h and moderate for wind velocity below 7 km/h and the distribution pattern gets distorted at high wind velocity of 15 km/h

Entropy function for rotating extremal black holes in very special geometry

We use the relation between extremal black hole solutions in five- and in four-dimensional N=2 supergravity theories with cubic prepotentials to define the entropy function for extremal black holes with one angular momentum in five dimensions. We construct two types of solutions to the associated attractor equations.Comment: 15 pages, minor change