Computational Mechanism Design: A Call to Arms

Game theory has developed powerful tools for analyzing decision making in systems with multiple autonomous actors. These tools, when tailored to computational settings, provide a foundation for building multiagent software systems. This tailoring gives rise to the field of computational mechanism design, which applies economic principles to computer systems design

A Computer Model to Select Optimum Size of Farm Power and Machinery for Paddy-Wheat Crop Rotation in Northern India

Selection of proper size of farm power and machinery is the most important component of any farm enterprise. Among the various inputs to the crop production system, power and machinery jointly represent the largest single item of expenditure constituting about 60% of the total investment on a farm. The decision on optimum size of machinery is quite critical not only because of the high proportion of total cost attributed to machinery but also due to the infrequency and irrevocability of such decisions. Computer based least cost models were developed in C programming language for the selection of optimum size power and machinery system for paddy-wheat cropping system with the input like area under the crop, soil type, number of operations for each crop, crop rotation and time available for each operation etc. The model selected the optimum tractor size from amongst the available sizes and its matching implements keeping in view the capacity of machinery to complete the operation in scheduled time for the given farm. The model also computes the working hours and energy requirement for different field operations along with various cost components. The model output was found to be sensitive to various input parameters like farm size, tillage intensity and crop rotation. Chi-square test revealed that there was no significant difference between the actual size of farm power owned by the farmers of the study area and the prediction of the model. Thus, the model predictions are good for paddy-wheat crop rotation of the study area and can be used successfully for selection of optimal power and machinery

Effect of simultaneous application of field and pressure on magnetic transitions in La0.5{_{0.5}}Ca0.5{_{0.5}}MnO3{_{3}}

We study combined effect of hydrostatic pressure and magnetic field on the magnetization of La${_{0.5}}$Ca${_{0.5}}$MnO${_{3}}$. We do not observe any significant effect of pressure on the paramagnetic to ferromagnetic transition. However, pressure asymmetrically affects the thermal hysteresis across the ferro-antiferromagnetic first-order transition, which has strong field dependence. Though the supercooling (T*) and superheating (T**) temperatures decrease and the value of magnetization at 5K (M$_{5K}$) increases with pressure, T* and M$_{5K}$ shows abrupt changes in tiny pressure of 0.68kbar. These anomalies enhance with field. In 7Tesla field, transition to antiferromagnetic phase disappears in 0.68kbar and M$_{5K}$ show significant increase. Thereafter, increase in pressure up to $\sim$10kbar has no noticeable effect on the magnetization

Computational-Mechanism Design: A Call to Arms

Game theory has developed several powerful tools for analyzing decision making in systems composed of multiple autonomous actors. Given this fact, AI practitioners would like to exploit these tools when building software systems containing multiple agents. However, to do this, the tools must be tailored to computational settings. To this end, the authors provide an overview of computational-mechanism design, which deals with the application of economic principles in computer systems design. Moreover, because many complex systems are inherently distributed, they also present initial results from the relatively new field of distributed-computational-mechanism design and outline the key challenges involved in making the ideas practicable.Engineering and Applied Science

Heat and mass transfer on MHD flow through a porous medium over a stretching surface with heat source

An attempt has been made to study the heat and mass transfer effect on the flow over a stretching sheet in the presence of a heat source. The novelty of the present study is to consider the span wise variation of magnetic field strength, heat source and heat flux. It is also considered the effect of viscous dissipation. The method of solution involves similarity transformation which leads to an exact solution of velocity field. The coupled non-linear and non homogeneous heat equation has been solved by applying Kummer’s function. The non-homogeneity of the heat equation is contributed by the consideration of viscous dissipative energy. KYEWORDS: Heat source, Viscous dissipation, Porous medium, Kummer’s function

Sorption of hexavalent chromium from synthetic waste water using dolochar

The adsorption characteristics of hexavalent chromium on dolochar, a low cost natural adsorbent, were studied in the laboratory. Dolochar was found to be an efficient adsorbent for chromium removal from synthetic waste water. Dolochar which is a solid waste generated by the sponge iron industry, is processed and put to test as an adsorbent for removal of Cr (VI) ions from aqueous solution. In this paper an attempt has been made to investigate the properties (i.e. physical and chemical) so as to reutilize it as absorbent to absorb the pollutants present in water. The adsorption behavior of dolochar using batch shaking has been studied to remove hexavalent chromium from synthetic waste water. The physical properties of dolochar such as specific gravity, void ratio, porosity, density and chemical properties such as chemical composition have been analyzed. Batch adsorption experiment have been conducted by varying adsorbent dose, adsorbate concentration, pH, particle size, time on removal of chromium of these metal ions. It was found that more than 94% of the removal was achieved under optimal condition

Spin precession and inverted Hanle effect in a semiconductor near a finite-roughness ferromagnetic interface

Although the creation of spin polarization in various non-magnetic media via electrical spin injection from a ferromagnetic tunnel contact has been demonstrated, much of the basic behavior is heavily debated. It is reported here for semiconductor/Al2O3/ferromagnet tunnel structures based on Si or GaAs that local magnetostatic fields arising from interface roughness dramatically alter and even dominate the accumulation and dynamics of spins in the semiconductor. Spin precession in the inhomogeneous magnetic fields is shown to reduce the spin accumulation up to tenfold, and causes it to be inhomogeneous and non-collinear with the injector magnetization. The inverted Hanle effect serves as experimental signature. This interaction needs to be taken into account in the analysis of experimental data, particularly in extracting the spin lifetime and its variation with different parameters (temperature, doping concentration). It produces a broadening of the standard Hanle curve and thereby an apparent reduction of the spin lifetime. For heavily doped n-type Si at room temperature it is shown that the spin lifetime is larger than previously determined, and a new lower bound of 0.29 ns is obtained. The results are expected to be general and occur for spins near a magnetic interface not only in semiconductors but also in metals, organic and carbon-based materials including graphene, and in various spintronic device structures.Comment: Final version, with text restructured and appendices added (25 pages, 9 figures). To appear in Phys. Rev.

Fitness and Metabolic Syndrome Components Affect Serum-Induced Endothelial Migration and MicroRNAs in Postmenopausal African-American Women

Please download pdf version here

Generalized information entropies depending only on the probability distribution

Systems with a long-term stationary state that possess as a spatio-temporally fluctuation quantity $\beta$ can be described by a superposition of several statistics, a "super statistics". We consider first, the Gamma, log-normal and $F$-distributions of $\beta$. It is assumed that they depend only on $p_l$, the probability associated with the microscopic configuration of the system. For each of the three $\beta-$distributions we calculate the Boltzmann factors and show that they coincide for small variance of the fluctuations. For the Gamma distribution it is possible to calculate the entropy in a closed form, depending on $p_l$, and to obtain then an equation relating $p_l$ with $\beta E_l$. We also propose, as other examples, new entropies close related with the Kaniadakis and two possible Sharma-Mittal entropies. The entropies presented in this work do not depend on a constant parameter $q$ but on $p_l$. For the $p_l$-Gamma distribution and its corresponding $B_{p_l}(E)$ Boltzmann factor and the associated entropy, we show the validity of the saddle-point approximation. We also briefly discuss the generalization of one of the four Khinchin axioms to get this proposed entropy.Comment: 13 pages, 3 figure

Optimal Bidding Strategies for Simultaneous Vickrey Auctions with Perfect Substitutes

We derive optimal bidding strategies for a global bidder who participates in multiple, simultaneous second-price auctions with perfect substitutes. We prove that, if everyone else bids locally in a single auction, the global bidder should always place non-zero bids in all available auctions, provided there are no budget constraints. With a budget, however, the optimal strategy is to bid locally if this budget is equal or less than the valuation. Furthermore, for a wide range of valuation distributions, we prove that the problem of finding the optimal bids reduces to two dimensions if all auctions are identical. Moreoever, we address markets with both sequential and simultaneous auctions, non-identical auctions, and the allocative efficiency of the market. Finally, by combining analystical and simulation results, we analyse equilibrium strategies in case of several global bidders. However, a stable solution is then only found if there are local bidders as well