A privacy-preserving technique for Euclidean distance-based mining algorithms using Fourier-related transforms

Privacy preserving data mining has become increasingly popular because it allows sharing of privacy-sensitive data for analysis purposes. However, existing techniques such as random perturbation do not fare well for simple yet widely used and efficient Euclidean distance-based mining algorithms. Although original data distributions can be pretty accurately reconstructed from the perturbed data, distances between individual data points are not preserved, leading to poor accuracy for the distance-based mining methods. Besides, they do not generally focus on data reduction. Other studies on secure multi-party computation often concentrate on techniques useful to very specific mining algorithms and scenarios such that they require modification of the mining algorithms and are often difficult to generalize to other mining algorithms or scenarios. This paper proposes a novel generalized approach using the well-known energy compaction power of Fourier-related transforms to hide sensitive data values and to approximately preserve Euclidean distances in centralized and distributed scenarios to a great degree of accuracy. Three algorithms to select the most important transform coefficients are presented, one for a centralized database case, the second one for a horizontally partitioned, and the third one for a vertically partitioned database case. Experimental results demonstrate the effectiveness of the proposed approach.     

Development of a Miniaturized Liquid Core Waveguide System With Nanoporous Dielectric Cladding—A Potential Biosensing Platform

We present a high-throughput optofluidic light waveguide system consisting of etched microchannels in silicon using water as the core and an ultra low refractive index nanoporous dielectric (ND) as the cladding organosilicate nanoparticulate films with refractive index of 1.16 have been used as the cladding layer. Although NDs offers many advantages over Teflon AF for use as the cladding layer, integration of these coatings to the waveguide design is not trivial. In this paper, we address the various integration issues of the NDs to the liquid core waveguide architecture followed by testing of these waveguides for their light guiding capability. Compared to uncoated channels, ND clad channels offer a high light guiding efficiency. In addition, the high surface areas associated with them could be potentially used to immobilize higher density of sensor probes implying a great potential for biosensor applications in an integrated system.     

Changes in the leukocyte phenotype profile of goats infected with the caprine arthritis encephalitis virus

The proportions of different sub-populations of leukocytes in five healthy goats and five goats infected with the caprine arthritis encephalitis virus (CAEV) were examined using immunofluorescence and flow cytometry. A panel of monoclonal antibodies that identified a monocytegranulocyte marker (GMI); the CD4, CD8, IgM, MHC Class I, MHC Class II and T19 antigens, and the gamma delta (gamma delta) T cell receptor was used. We observed a significant (P = 0.016) reduction in the proportion of monocytes in the peripheral blood of infected (5.98%) compared with healthy control goats (9.92%). There was also a decrease in the proportion of CD4+ T lymphocytes that approached significance (P = 0.076) accompanied by a slight increase in the proportion of CD8+ T lymphocytes, in infected compared with uninfected animals. Consequently, three of the five infected animals had lower CD4:CD8 ratios than any of the healthy animals and two of these three ratios were inverted. Approximately 14% of T cells in the peripheral blood of healthy goats was identified as gamma delta T cells and all expressed the T19 antigen. A significantly elevated level of gamma delta T cells (P = 0.030) and an elevated level of T19 cells were observed in infected, compared with healthy animals. The proportion of leukocytes expressing surface IgM (B cells) was also elevated, although not significantly, in CAEV-infected compared to healthy controls. The changes in peripheral blood leukocyte subsets in infected goats suggest that immune responses to the infection are probably altered in these animals with eventual progression to severe disease and death.     

Microfabrication and characterization of teflon AF-coated liquid core waveguide channels in silicon

The fabrication and testing of Teflon AF-coated channels on silicon and bonding of the same to a similarly coated glass wafer are described. With water or aqueous solutions in such channels, the channels exhibit much better light conduction ability than similar uncoated channels. Although the loss is greater than extruded Teflon AF tubes, light throughput is far superior to channels described in the literature consisting of [110] planes in silicon with 45/spl deg/ sidewalls. Absorbance noise levels under actual flow conditions using an LED source, an inexpensive photodiode and a simple operational amplifier circuitry was 1/spl times/ 10/sup -4/ absorbance units over a 10-mm path length (channel 0.17-mm deep /spl times/0.49-mm wide), comparable to many commercially available macroscale flow-through absorbance detectors. Adherence to Beer's law was tested over a 50-fold concentration range of an injected dye, with the linear r/sup 2/ relating the concentration to the observed absorbance being 0.9993. Fluorescence detection was tested with fluorescein as the test solute, a high brightness blue LED as the excitation source and an inexpensive miniature PMT. The concentration detection limit was 3 /spl times/ 10/sup -9/ M and the corresponding mass detection limit was estimated to be 5 /spl times/ 10 /sup -16/ mol.     

Abdominal cocoon in children: a report of four cases

Abdominal cocoon is a rare cause of intestinal obstruction. The authors report four cases (3 boys, 1 girl; age range, 6 to 8 years) that presented with features of intestinal obstruction. There was no history of previous surgery, peritonitis, or prolonged drug intake in any of these cases. One patient presented with acute intestinal obstruction and gangrene of bowel. The etiology, preoperative diagnosis, and management of this condition are discussed.     

Functional nanostructures through nanosecond laser dewetting of thin metal films

Techniques for processing nanoscale metallic structures with spatial order and tunable physical characteristics, such as size and microstructure, are paramount to realizing applications in the areas of magnetism, optics, and sensing. This paper discusses how pulsed laser melting of ultrathin films can be a powerful but simple and cost-effective technique to fabricate functional nanostructures. Ultrathin metal films (1 nm to 1,000 nm) on inert substrates like SiO₂ are generally unstable, with their free energy resembling that of a spinodal system. Such films can spontaneously evolve into predictable nanomorphologies with well-defined length scales. This study reviews this laser-based experimental technique and provides examples of resulting robust nanostructures that can have applications in magnetism and optics.     

Compensation of chromatic dispersion-induced power fading using optimised chirped fibre Bragg grating for millimetre-wave radio-over-fibre system

Compensation of fibre dispersion-induced power fading in an externally modulated sub- carrier multiplexed radio-over-fibre transmission link using the chirped fibre Bragg grating (CFBG) has been investigated. The results show that periodic power fading caused by fibre chromatic dispersion is significantly reduced and the optimum transmission distance can be increased by proper design of grating parameters and optimum selection of apodisation profile. The investigation also reveals that carrier-to-noise ratio and bit-error rate of 156 Mbps DPSK signal are also significantly improved using the CFBG with asymmetric apodisation profile as the dispersion compensator.     

Novel process for low temperature crystallization of a-SiC:H for optoelectronic applications

Metal-induced crystallization (MIC) process was employed to crystallize hydrogenated amorphous silicon carbide (a-SiC:H) films deposited by PECVD on n-type Si substrate. To optimize the crystallization process, Aluminum thin films of different thicknesses were deposited on a-SiC:H films which were then annealed at 600 °C in N₂ environment for 1 h. UV–visible spectrophotometer, atomic force microscopy (AFM) and hall measurement system were used to characterize the films. It was observed from the UV–visible spectrum that the films crystallized using higher Al thickness show absorption in the visible range whereas the samples crystallized with lower Al thickness did not show absorption in the visible range but shows large absorption above the bandgap of the material. Considering UV–visible and Hall measurement data it can be concluded that the sample crystallized with 50 nm of Al can be a good candidate for SiC–Si hetero-junction solar cells.