A simple algorithm for nearest neighbor search in high dimensions

The problem of finding the closest point in high-dimensional spaces is common in pattern recognition. Unfortunately, the complexity of most existing search algorithms, such as k-d tree and R-tree, grows exponentially with dimension, making them impractical for dimensionality above 15. In nearly all applications, the closest point is of interest only if it lies within a user-specified distance ϵ. We present a simple and practical algorithm to efficiently search for the nearest neighbor within Euclidean distance ϵ. The use of projection search combined with a novel data structure dramatically improves performance in high dimensions. A complexity analysis is presented which helps to automatically determine ϵ in structured problems. A comprehensive set of benchmarks clearly shows the superiority of the proposed algorithm for a variety of structured and unstructured search problems. Object recognition is demonstrated as an example application. The simplicity of the algorithm makes it possible to construct an inexpensive hardware search engine which can be 100 times faster than its software equivalent. A C++ implementation of our algorithm is available     

DSP based inverter control for alternate energy systems

This paper presents a DSP based algorithm to control inverters used in interfacing alternate energy systems with the electric utility. Since a constant and ripple free dc bus voltage is not ensured at the output of alternate energy sources, the main aim of the proposed algorithm is to make the output of the inverter immune to the fluctuations in the dc input voltage. In this paper a modified space vector pulse width modulation (SVPWM) technique is proposed which will maintain the quality of the ac output of the inverter, regardless of the ripple present at the inverter input. The principle is explained qualitatively and extensive experiments have been carried out to verify and validate the proposed algorithm. A 16-bit fixed-point C2000 family DSP from Texas Instruments was used as the controller to implement the proposed control algorithm.     

Decision Making in the Battlefield-of-Things

Wireless Personal Communications - This paper accentuates the paradigm shift in battlefield-environments. In perspective of a decision-maker to enable shrinking of his decision-cycle, the...     

New avenues in membrane science and technology

Recent advances and avenues for further research and development in three specific fields of membrane science and technology are reviewed. The potential of membrane processes for gas separation has been considerably improved by the development of new materials combining high permeability and selectivity. While working correlations between polymer structure and permeation characteristics have been evolved, there is need to further develop our basic understanding of this relationship. The second field reviewed is that of improving the separation characteristics of porous membrane filtration (ultra-/microfiltration). Recent promising approaches include the fabrication of membranes with uniform porosities, new module configurations and the manipulation of feed chemistries. The third area highlighted is that of hybrid membrane processes. These are considered both as integrated processes in which the membrane process operates in conjunction with another unit operation or as a coupled transport process in which the basic functioning of the membrane is intimately coupled with another physical or chemical process in single unit operation. The scope for basic research in these fields is indicated.     

Baculovirus surface display of Theileria parva p67 antigen preserves the conformation of sporozoite-neutralizing epitopes

Theileria parva is an intracellular protozoan parasite thatcauses East Coast fever, a severe lymphoproliferative diseasein cattle. Previous attempts to produce recombinant sporozoitesurface antigen (p67) in bacterial or insect cells for vaccinepurposes have not resulted in a correctly folded protein. Here,we report the expression of N- and C-terminal domains of p67fused to the baculovirus envelope glycoprotein GP64 by cloningthe appropriate p67 cDNA segments between the signal sequenceand the major portion of GP64. To further advance the generationof such recombinants, existing surface display techniques werecombined with bacmid technology. Chimeric proteins were presenton the surface of budded viruses as judged by immunogold labellingand were exposed on the surface of insect cells, as concludedfrom immunofluorescence studies of infected, non-fixed insectcells. In non-denaturing dot blot experiments, a strong reactionwas obtained between monoclonal TpM12 and baculovirus particlesdisplaying the p67N-GP64 chimeric protein. This antibody, raisedagainst native p67, also specifically recognized the surfaceof recombinant-infected cells. Apparently, a more native conformationwas achieved than when p67 was expressed in E.coli or in conventionalbaculovirus expression systems. The baculovirus surface expressionsystem, therefore, provides an improved way of expressing thisT.parva sporozoite surface protein.