Prospects and problems in designing image oriented information systems

There are slowly maturing and growing about us today a number of techniques which are likely to have a very significant effect upon the implementation of information systems in the near future. One of these techniques is pictorial data handling and interpretation, which is a subclass of the general area called pattern recognition. Pictorial data processing first became volumetrically significant in the case of photographic output of synchrotron bubble chambers which now deliver several million photographs per year. More recently, a surge of interest has developed in automatic interpretation of biological, medical, and weather satellite pictorial data. The automatic scanning of microscopic slides for the purpose of identifying certain morphological characters is an example of a rather complex task in the area of biological/medical laboratory automation. Some new viewpoints have begun to emerge from the experience of grappling with large volume pictorial data handling problems.published or submitted for publicatio

The Reform and Design of Commodity Taxes in the Presence of Tax Evasion with Illustrative Evidence from India

The literature on tax evasion and its implication for optimal tax theory has concentrated on income tax evasion. The issue of commodity tax evasion has received relatively little attention even though it is important in many cases, especially in developing countries. This paper proposes a theory of marginal reform of indirect taxes that recognises the presence of commodity tax evasion. Illustrative evidence from Indian data confirm the sensitivity of the Pareto improving direction of marginal tax changes to alternative a priori assumptions on commodity tax evasion. The theory of marginal reform of commodity taxes is, then, extended to propose a theory of marginal reform of audits and penalties, and several propositions are derived. The underlying theory of tax design is also extended to include income tax design and income tax evasion, and a framework is proposed to allow the simultaneous analyses of both forms of tax evasion, and study of their impact on the "optimal mix" of direct and indirect taxes.

Finite Temperature and Density Effects in Planar Q.E.D

The behavior of finite temperature planar electrodynamics is investigated. We calculate the static as well as dynamic characteristic functions using real time formalism. The temperature and density dependence of dielectric and permeability functions, plasmon frequencies and their relation to the screening length is determined. The radiative correction to the fermion mass is also calculated. We also calculate the temperature dependence of the electron (anyon) magnetic moment. Our results for the gyromagnetic ratio go smoothly to the known result at zero temperature, $g=2$, in accordance with the general expectation.Comment: 24 pages, LaTe

Bulk and Edge excitations in a ν=1\nu =1 quantum Hall ferromagnet

In this article, we shall focus on the collective dynamics of the fermions in a $\nu = 1$ quantum Hall droplet. Specifically, we propose to look at the quantum Hall ferromagnet. In this system, the electron spins are ordered in the ground state due to the exchange part of the Coulomb interaction and the Pauli exclusion principle. The low energy excitations are ferromagnetic magnons. To provide a means for describing these magnons, we shall discuss a method of introducing collective coordinates in the Hilbert space of many-fermion systems. These collective coordinates are bosonic in nature. They map a part of the fermionic Hilbert space into a bosonic Hilbert space. Using this technique, we shall interpret the magnons as bosonic collective ex citations in the Hilbert space of the many-electron Hall system. By considering a Hall droplet of finite extent, we shall also obtain the effective Lagrangian governing the spin collective excitations at the edge of the sample.Comment: Plain TeX 18 Pages Proceedings for the Y2K conference on strongly c orrelated fermionic systems, Calcutta, Indi

Comment on "A note on the construction of the Ermakov-Lewis invariant"

We show that the basic results on the paper referred in the title [J. Phys. A: Math. Gen. v. 35 (2002) 5333-5345], concerning the derivation of the Ermakov invariant from Noether symmetry methods, are not new

A new internal combustion engine configuration: opposed pistons with crank offset

[Abstract]: Theoretical and experimental performance results for a new internal combustion engine configuration are presented in this paper. The engine is a piston ported, spark ignition petrol engine which consists of two opposed pistons in a single cylinder controlled by two synchronously timed crankshafts at opposite ends of the cylinder. It makes use of crank offset to create the required piston motion aimed at engine efficiency improvements through thermodynamic performance gains. In particular, the engine employs full expansion in which the power stroke displaces a larger volume than the compression stroke, thereby allowing the expanding gas to reach near atmospheric pressure before the exhaust port opens. This allows more work to be done by each thermodynamic cycle. It also features a greater rate of volume change after combustion than a convention 4-stroke engine for the same crank speed. This reduces the time that the temperature difference between the gas and the cylinder is high relative to a conventional engine which in turn, should reduce the heat lost from the combustion products. Thermodynamic and friction modelling of the engine indicated that efficiencies around 38% might be achieved. However, experiments with a prototype engine demonstrated that friction losses in the engine exceeded that predicted in the original modelling