A Formal Model for Video Shot Segmentation and its Application via Animate Vision

The first step in a video indexing process is the segmentation of videos into meaningful parts called shots. In this paper we present a formal model of the video shot segmentation process. Starting from a mathematical characterization of the most common transition effects, a video segmentation algorithm capable to detect both abrupt and gradual transitions is proposed. The proposed algorithm is based on the computation of an arbitrary similarity measure between consecutive frames of a video. The algorithm has been tested adopting a similarity metric based on the Animate Vision theory and results have been reported.     

A dry process for production of microfluidic devices based on the lamination of laser-printed polyester films

A new microfabrication process based on a xerographic process is described. A laser printer is used to selectively deposit toner on a polyester film, which is subsequently laminated against another polyester film. The toner layer binds the two polyester films and allows the blank regions to become channels for microfluidics. These software-outlined channels are approximately 6 microm deep. Approximately twice this depth is obtained by laminating two printed films. The resulting devices were not significantly damaged after 24 h of exposure to aqueous solutions of H3PO4, NaOH, methanol, acetonitrile, or sodium dodecyl sulfate. Electric tests with an impedance analyzer and microchannels filled with KCl solution demonstrated that (1) wide channels suffer from deformation of the top and bottom walls due to the lamination of the polyester films and (2) the toner walls are somewhat porous. Although these drawbacks limit the maximum width of a channel and the minimum distance between two channels, the process is an attractive option to other expensive, laborious, and time-consuming methods for microchannels fabrication. The process has been used to implement devices for electrospray tip and capillary electrophoresis with contactless conductivity detection.     

Employing virtual humans for education and training in X3D/VRML worlds

Web-based education and training provides a new paradigm for imparting knowledge; students can access the learning material anytime by operating remotely from any location. Web3D open standards, such as X3D and VRML, support Web-based delivery of Educational Virtual Environments (EVEs). EVEs have a great potential for learning and training purposes, by allowing one to circumvent physical, safety, and cost constraints. Unfortunately, EVEs often leave to the user the onus of taking the initiative both in exploring the environment and interacting with its parts. A possible solution to this problem is the exploitation of virtual humans acting as informal coaches or more formal instructors. For example, virtual humans can be employed to show and explain maintenance procedures, allowing learners to receive more practical explanations which are easier to understand. However, virtual humans are rarely used in Web3D EVEs, since the programming effort to develop and re-use them in different environments can be considerable. In this paper, we present a general architecture that allows content creators to easily integrate virtual humans into Web3D EVEs. To test the generality of our solution, we present two practical examples showing how the proposed architecture has been used in different educational contexts.     

Postfailure Mechanics of Landslides: Laboratory Investigation of Flowslides in Pyroclastic Soils

Of all landslides, subaerial flowslides are the most dangerous. According to the literature, flowslides in saturated granular deposits are caused by static liquefaction induced by loss of stability. However, the catastrophic flowslides that occurred on steep slopes in Campania (southern Italy) in 1998, 1999, and 2005 were triggered by rainwater infiltration into shallow deposits of pyroclastic soils, which were initially unsaturated. Starting from the experience collected during the investigations of some of these landslides, the writers consider flowslide evolution as a result of a mechanical chain process characterized by saturation increase due to rainwater infiltration, mechanical degradation, volumetric collapse, and static liquefaction, culminating in complete fluidization of the soil. In the paper this chain process is investigated through wetting tests both in suction controlled triaxial apparatuses and in a well-equipped small scale slope model.     

Knowledge-Assisted Retrieval of Online Product Information in Architectural/Engineering/Construction

With a better understanding about the product market, industry practitioners can make more informed decisions for product specification, selection, and procurement. However, current approaches that support Architectural/Engineering/Construction (A/E/C) information acquisition do not provide a comprehensive market scan. While the Internet provides an ever-growing resource for product information, existing approaches have limited capabilities to make use of this virtual market. Therefore, the writers have developed a knowledge-assisted approach to specifically address the potential of the virtual market—help retrieve A/E/C product information, particularly information about different manufacturers, from the Internet. The paper introduces the building blocks of the developed approach, which includes domain knowledge utilization, information retrieval (IR) techniques, and strategies that incorporate domain knowledge into knowledge-supported IR approaches. Specifically, domain knowledge represented in the form of a thesaurus was used with query expansion strategies under the framework of an adaptation of the extended IR Boolean model. It was concluded from the prototype validation that domain knowledge can be extremely helpful when acquiring A/E/C product information from online resources using the developed approach.     

Differential ionisation measurements for positron impact

An overview of methods being used at the University of Missouri-Rolla to measure differential ionisation for positron impact is presented. Examples of triply differential electron emission and doubly differential positron scattering and energy loss data are given and contributions to each due to binary and recoil events are discussed. In addition, angular distribution data for electron emission due to double and triple ionisation are presented.     

Integral transform solution for hyperbolic heat conduction in a finite slab

An analytical integral transformation of the thermal wave propagation problem in a finite slab is obtained through the generalized integral transform technique (GITT). The use of the GITT approach in the analysis of the hyperbolic heat conduction equation leads to a coupled system of second order ordinary differential equations in the time variable. The resulting transformed ODE system is then numerically solved by Gear's method for stiff initial value problems. Numerical results are presented for the local and average temperatures with different Biot numbers and dimensionless thermal relaxation times, permitting a critical evaluation of the technique performance. A comparison is also performed with previously reported results in the literature for special cases and with those produced through the application of the Laplace transform method (LTM), and the finite volume-Gear method (FVGM).     

Sliding Discharge Optical Emission Characteristics

In this work, several optical studies in an atmospheric pressure sliding plasma sheet have been performed. This discharge is generated using two electrodes flush mounted on an insulating flat plate (upper electrodes), and a third electrode flush placed on the opposite side of the plate facing the upper inter electrode gap (lower electrode). A DC negative voltage is applied to one of the two upper electrodes and to the lower electrode, while the other upper electrode is biased with an AC voltage. In this configuration a sliding discharge is produced on the flat plate within the upper electrodes gap. The sliding discharge optical emission of the spectral bands corresponding to the 0-0 transition of the second positive system of N₂ (lambda = 337.1 nm) and the first negative system of N₂ ⁺ (lambda = 391.4 nm) have been measured. Also the light spatial distribution in the plasma sheet has been studied using a CCD camera coupled to interferential filters corresponding to the wavelengths investigated. The reduced electric field in the plasma sheet has been derived from the measurement of the intensity ratio of the nitrogen lines. This study has been realized varying the amplitude of the DC voltage and the amplitude and frequency of the AC voltage. The reduced electric field strength is found to be almost constant for all the experimental conditions, with a value of 500 plusmn 100 Td (1 Td = 1.10^-17 V cm²).     

Development of a Four-Channel Potentiostat for Amperometric Detection in Flow Injection Analysis

Abstract

A four-channel multipotentiostat has been developed for simultaneous voltammetric measurements with microelectrode arrays. To reduce the complexity of electrochemical cell, only one reference and one auxiliary electrode are used. The potential ranges of the four working electrodes may be independently controlled, but they are synchronously scanned by only one DAC. This is accomplished through a microcomputer interfaced with a PCL-711B data acquisition board, which allows the continuous monitoring of the currents and actual potentials of the working electrodes.

The system has been applied to the simultaneous determination of ascorbic and uric acids in synthetic samples. The measurements were carried out with gold microelectrodes modified by deposition of noble metals, which enhance the electrocatalysis and provide an anticipation and a better definition of the oxidation potentials. Recuperation of 98.2% and 97.8% for ascorbic and uric acids, respectively, was obtained by using amperometry.     

Relation among taste-related compounds (phenolics and caffeine) and sensory profile of erva-mate (Ilex paraguariensis)

Erva-mate (Ilex paraguariensis St. Hil.) is a native species from temperate regions of South America, such as Brazil, Paraguay, and Argentina, that is consumed as a beverage known as mate. The objective of this research was to determine the content of caffeic acid, catechin, chlorogenic acid, caffeine, and gallic acid in mate to explain their influence in beverage taste and sensory differences between native and reforested plants, as well as between beverages from plants of different regions of Brazil (Santa Catarina and Rio Grande do Sul states). Compounds were determined by HPLC and results were related to a sensory evaluation performed by trained tasters. Tasters considered the beverage from reforested plants to be more bitter than the beverage from native plants. Beverages from reforested plants had significantly higher caffeic acid and lower catechin, chlorogenic acid, caffeine, and gallic acid content than native plants. Beverages from plants of Santa Catarina state had significantly higher catechin, caffeine, and gallic acid content than plants from Rio Grande do Sul state.