Estimating the Optimal Margins of Embeddings in Euclidean Half Spaces

Concept classes can canonically be represented by matrices with entries 1 and –1. We use the singular value decomposition of this matrix to determine the optimal margins of embeddings of the concept classes of singletons and of half intervals in homogeneous Euclidean half spaces. For these concept classes the singular value decomposition can be used to construct optimal embeddings and also to prove the corresponding best possible upper bounds on the margin. We show that the optimal margin for embedding n singletons is and that the optimal margin for half intervals over {1,...,n} is . For the upper bounds on the margins we generalize a bound by Forster (2001). We also determine the optimal margin of some concept classes defined by circulant matrices up to a small constant factor, and we discuss the concept classes of monomials to point out limitations of our approach.     

Electric manipulation of bioparticles and macromolecules on microfabricated electrodes

Bioparticle separation, bioparticle enrichment, and electric field-mediated immune detection were carried out on microfabricated semiconductor chips utilizing ac and dc electric fields. Microscale separation on a chip surface having an active area of approximately 16 mm2 was demonstrated for a mixture of Bacillus globigii spores and Escherichia coli bacteria. Dielectrophoretic enrichment was performed by collecting target bioparticles from a flow stream in flow cells of 47.5 microL, achieving a 20-fold increase in the concentration of E. coli bacteria from a diluted sample, a 28-fold enrichment for peripheral blood mononuclear cells from red blood cells, and a 30-fold increase in white blood cells from diluted whole blood. The ability to manipulate and collect bioparticles and macromolecules at microfabricated electrodes with ac and dc fields was further illustrated in electric field-mediated immunoassays for analyzing the biological identities of E. coli bacteria and B. globigii spores. According to these results, the electric methods for manipulating bioparticles present themselves as viable techniques for novel biomedical applications in sample preparations and biochemical assays on microelectrode arrays.     

Speckle suppression using recursive wavelet transforms

An effective algorithm for digital image noise smoothing using wavelet transform techniques is presented in this paper. This algorithm is more powerful when compared to other existing filtering algorithms in terms of speckle suppression for synthetic aperture radar images where the presence of speckle makes the ratio of standard deviation to mean (STM) very high. Examples show that the original STM of about 0.30 (equivalent to three-look images) can be reduced to 0.05-0.03 (equivalent to more than 100-look images), with a possible small sacrifice of losing some details and narrow edges. The quantitative analysis is carried out and compared with the results of some existing filtering algorithms including median, K nearest neighbour averaging, Lee's multiplicative and Crimmins' geometric filters, showing that imagery filtered by the wavelet transform is the smoothest.     

``Cell Shocks'? Not Necessary in Chlorine Cell Rooms

Electrical safety hazards in chlorine electrolytic cell rooms have been thoroughly discussed in previous papers. However, no attempt has ever been made to show the importance of maintaining maximum leakage resistance from the electrolytic cell line to ground. The majority of electrical shocks received by electrolytic cell room personnel are from the energized bus or chlorine cells to ground. As electrolytic cell lines are normally not grounded, the leakage resistance to ground has a definite effect on the severity of the majority of electrical shocks received by personnel. The leakage resistance problem is explained with the use of simple circuit diagrams, and solutions are suggested to eliminate electrical shocks to cell room personnel.     

Zeitschriftenreferate: Allgemeine Bestandteile der Lebensmittel

Ohne Zusammenfassung     

3-D analysis of the breakdown localised defects of ACS through a triac study

The reliability tests of triac and ACS^TM present similarities. In this paper, we propose to analyse the origin of the defects observed by using measurements and 3D simulation with the ISE tools. We are interested in the operation of the triac or ACS^TM in quadrant 2. The results presented here relate to the discrete triac only for reasons of confidentiality. Thermal simulation of the triac shows a strong thermal gradient (thermal shock) in the silicon at turn-on. Stresses and strains in the material created micro crackings that increase the temperature until the fusion of silicon (hot spot).