A Quotient Space Formulation for Generative Statistical Analysis of Graphical Data

Complex analyses involving multiple, dependent random quantities often lead to graphical models—a set of nodes denoting variables of interest, and corresponding edges denoting statistical interactions between nodes. To develop statistical analyses for graphical data, especially towards generative modeling, one needs mathematical representations and metrics for matching and comparing graphs, and subsequent tools, such as geodesics, means, and covariances. This paper utilizes a quotient structure to develop efficient algorithms for computing these quantities, leading to useful statistical tools, including principal component analysis, statistical testing, and modeling. We demonstrate the efficacy of this framework using datasets taken from several problem areas, including letters, biochemical structures, and social networks.

     

Perceptual Organization Based Computational Model for Robust Segmentation of Moving Objects

The role of perceptual organization in motion analysis has heretofore been minimal. In this work we present a simple but powerful computational model and associated algorithms based on the use of perceptual organizational principles, such as temporal coherence (or common fate) and spatial proximity, for motion segmentation. The computational model does not use the traditional frame by frame motion analysis; rather it treats an image sequence as a single 3D spatio-temporal volume. It endeavors to find organizations in this volume of data over three levels—signal, primitive, and structural. The signal level is concerned with detecting individual image pixels that are probably part of a moving object. The primitive level groups these individual pixels into planar patches, which we call the temporal envelopes. Compositions of these temporal envelopes describe the spatio-temporal surfaces that result from object motion. At the structural level, we detect these compositions of temporal envelopes by utilizing the structure and organization among them. The algorithms employed to realize the computational model include 3D edge detection, Hough transformation, and graph based methods to group the temporal envelopes based on Gestalt principles. The significance of the Gestalt relationships between any two temporal envelopes is expressed in probabilistic terms. One of the attractive features of the adopted algorithm is that it does not require the detection of special 2D features or the tracking of these features across frames. We demonstrate that even with simple grouping strategies, we can easily handle drastic illumination changes, occlusion events, and multiple moving objects, without the use of training and specific object or illumination models. We present results on a large variety of motion sequences to demonstrate this robustness.     

Enabling heterogeneous cycle-based and event-driven simulation in a design flow integrated using the SPIRIT consortium specifications

The practical application of electronic system-level (ESL) design has been a key challenge of transaction-level modeling (TLM) methodologies in the past few years. While the benefits of ESL are well known, making the investment pay-off has required two key factors to be resolved: the simulation speed of the virtual platform model has to be fast enough to enable software design, and the flow from ESL design to implementation has to be seamless. We introduce two themes to address these issues: cycle-based simulation and a multi-vendor design-flow integrated using the IP-XACT^TM specifications from The SPIRIT Consortium. Through experimentation with the ARM RealView^® SoC Designer flow, and the Synopsys coreAssembler tool and Galaxy suite of tools, we show that competent solutions to both of these adoption issues exist in the industry today.     

Attachment and biofilm formation by various serotypes of Salmonella as influenced by cellulose production and thin aggregative fimbriae biosynthesis

This study was undertaken to quantify thin aggregative fimbriae and cellulose produced by Salmonella and to evaluate their roles in attachment and biofilm formation on polystyrene and glass surfaces. Thin aggregative fimbriae and cellulose produced by four wild-type and two pairs of Salmonella, representing four different colony morphotypes (rdar: red, dry, and rough; pdar: pink, dry, and rough; bdar: brown, dry, and rough; and saw: smooth and white), were quantified. The ability of the Salmonella cells to attach and form biofilms on the selected surfaces was evaluated in Luria-Bertani (LB) broth with or without salt (0.5%) or glucose (2%) at 28 degrees C during a 7-day period. The cells expressing the rdar or pdar colony morphotypes produced significantly greater amounts of thin aggregative fimbriae and cellulose on LB no salt agar, respectively. The cells expressing the rdar colony morphotype attached in higher numbers and formed more biofilm than did the cells expressing the pdar colony morphotype. The members of the pairs expressing the bdar colony morphotype attached more efficiently and formed more biofilm on the tested surfaces than did their counterparts expressing the saw colony morphotype. These results indicated that thin aggregative fimbriae impart attachment ability to Salmonella and, upon coexpression with cellulose, enhance biofilm formation on certain abiotic surfaces. The knowledge acquired in the study may help develop better cleaning strategies for food processing equipment.     

Agglomeration of a model food powder: Effect of maltodextrin and gum Arabic dispersions on flow behavior and compacted mass

The process of agglomeration of particulate foods was studied by employing corn starch as a model system. The effect of different liquid binders (maltodextrin and gum Arabic) to the extent of 1–5% was used to study the changes in the characteristics of the powder. Rheological behavior of powder was quantified in terms of textural indices like maximum force, and energy of compression and decompression. The physical and functional properties of powder and that of the pressure-compacted masses were determined to understand the behavior of the particulate foods in presence of binder liquid. The compacted masses were subjected to compression testing to obtain textural indices like strain at failure and Young’s modulus. The different concentrations of gum and maltodextrin improved the wettability of powder. The electron micrographs were used to observe the characteristics of agglomerated particles including shape and size. The latter varied between 30 and 100 μm for agglomerated masses compared to 12 μm for untreated corn starch powder.     

Antibiotic resistance profiles and cell surface components of Salmonellae

Salmonellae were isolated from raw chilled retail poultry meats (n=100) using the procedures outlined in the Bacteriological Analytical Manual and Microbiology Laboratory Guidebook. These isolates and 36 Salmonella strains from our laboratory culture collection were tested for their resistance to 12 different antibiotics and for their ability to produce thin aggregative fimbriae and/or cellulose, two of the most important surface components influencing the ability of cells to attach to surfaces and form biofilms. The sensitivity of the salmonellae to the antibiotics was determined with a disc diffusion assay. Of 52 Salmonella isolates, 25 (48.0%) were resistant to one antibiotic, 5 (9.6%) were resistant to two, 4 (7.7%) were resistant to three, 6 (11.5%) were resistant to four, and 5 (9.6%) were resistant to five antibiotics. Two (3.8%) of the isolates were resistant to up to nine of the antibiotics tested. Fifty-one (98%) of the isolates were resistant to novobiocin, 18 (34.6%) were resistant to streptomycin, 14 (26.9%) were resistant to tetracycline, and 14 (26.9%) were resistant to oxytetracycline. In separate experiments, the isolates were grown on Luria-Bertani no-salt agar supplemented with Congo red (40 microg/ml) and Coomassie brilliant blue (20 microg/ml) or Calcofluor (200 microg/ml) to determine whether they produced thin aggregative fimbriae and/or cellulose. Of the total 52 Salmonella isolates, 25 expressed only thin aggregative fimbriae, and 1 synthesized only cellulose. Ten isolates produced both thin aggregative fimbriae and cellulose, and the remaining 16 isolates expressed neither surface structure. The findings of this study reveal a prevalence of Salmonella on raw retail poultry products in central Georgia and suggest that salmonellae have the ability to develop resistance to multiple antibiotics and to synthesize cell surface components that help them survive in hostile or suboptimal environments.     

EVBlocks: A Blockchain-Based Secure Energy Trading Scheme for Electric Vehicles underlying 5G-V2X Ecosystems

Wireless Personal Communications - In this paper, the authors propose a secure and trusted energy trading (ET) scheme for electric vehicles (EVs) for vehicle-to-anything (V2X) ecosystems. The...     

Deciphering the flow structure of Czochralski melt using Partially Averaged Navier–Stokes (PANS) method

Czochralski melt flow is an outcome of complex interactions of centrifugal, buoyancy, coriolis and surface tension forces, which act at different length and time scales. As a consequence, the characteristic flow structures that develop in the melt are delineated in terms of recirculating flow cells typical of rotating Bénard–Marangoni convection. In the present study, Partially Averaged Navier–Stokes (PANS) method is used for the first time to study an idealized Czochralski crystal growth set-up. It is observed that with a reduction in the PANS filter width, more turbulent scales are resolved and the present PANS model is able to resolve almost all the characteristic flow structures in the Czochralski flow at a comparatively lower computational cost compared with more advanced turbulence modelling tools, such as Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES).     

Kinetically trapped co-continuous polymer morphologies through intraphase gelation of nanoparticles

We describe an approach to prepare co-continuous microstructured blends of polymers and nanoparticles by formation of a percolating network of particles within one phase of a polymer mixture undergoing spinodal decomposition. Nanorods or nanospheres of CdSe were added to near-critical blends of polystyrene and poly(vinyl methyl ether) quenched to above their lower critical solution temperature. Beyond a critical loading of nanoparticles, phase separation is arrested due to the aggregation of particles into a network (or colloidal gel) within the poly(vinyl methyl ether) phase, yielding a co-continuous spinodal-like structure with a characteristic length scale of several micrometers. The critical concentration of nanorods to achieve kinetic arrest is found to be smaller than for nanospheres, which is in qualitative agreement with the expected dependence of the nanoparticle percolation threshold on aspect ratio. Compared to structural arrest by interfacial jamming, our approach avoids the necessity for neutral wetting of particles by the two phases, providing a general pathway to co-continuous micro- and nanoscopic structures.