Interactive Selective and Adaptive Clustering for Detection of Microcalcifications in Mammograms

Estevez, L., Kehtarnavaz, N., and Wendt, R. III, Interactive Selective and Adaptive Clustering for Detection of Microcalcifications in Mammograms,Digital Signal Processing6(1996), 224–232.This paper presents a clustering algorithm, called interactive selective and adaptive clustering (Isaac), to assist radiologists in looking for small clusters of microcalcifications in mammograms. Isaac is developed to identify suspicious microcalcification regions which are missed by other classification techniques due to false positive samples in the feature space. It comprises two parts: (i) selective clustering and (ii) interactive adaptation. The first part reduces the number of false positives by identifying the microcalcification subspace or domains in the feature space. The second part allows the radiologist to improve results by interactively identifying additional false positive or true negative samples. Clinical evaluations of mammograms indicate the potential of using this algorithm as an effective tool to bring microcalcification areas to the attention of the radiologist during a routine reading session of mammograms.     

On the Ontological Status of Plans and Norms

This article describes an ontological model of norms. The basic assumption is that a substantial part of a legal system is grounded on the concept of agency. Since a legal system aims at regulating a society, then its goal can be achieved only by affecting the behaviour of the members of the society. We assume that a society is made up of agents (which can be individuals, institutions, software programs, etc.), that agents have beliefs, goals and preferences, and that they commit to intentions in order to choose a line of behaviour. The role of norms, within a legal system, is to specify how and when the chosen behaviour agrees with the basic principles of the legal system. In this article, we show how a model based on plans can be the basis for the ontological representation of norms, which are expressed as constraints on the possible plans an agent may choose to guide its behaviour. Moreover, the paper describes how the proposed model can be linked to the upper level of a philosophically well-founded ontology (DOLCE); in this way, the model is set in a wider perspective, which opens the way to further developments.     

Houghton anastigmatic telescope containing aspheric mirrors that allows corrector position as a free parameter

A family of catadioptric telescopes is investigated, characterzied with two-element, full-aperture afocal corrector lenses and aspherical, focusing, primary mirrors or primary-secondary mirror combination. Third-order aberration and design equation are provided for anastigmatic systems in which corrector position must be a free parameter, forcing the consideration of aspherics on the mirrored surfaces.     

Surface-enhanced Raman scattering substrate based on a self-assembled monolayer for use in gene diagnostics

The development of surface-enhanced Raman scattering (SERS)-active substrates for cancer gene detection is described. The detection method uses Raman active dye-labeled DNA gene probes, self-assembled monolayers, and nanostructured metallic substrates as SERS-active platforms. The mercaptohexane-labeled single-stranded DNA (SH-(CH(2))(6)-ssDNA)/6-mercapto-1-hexanol system formed on a silver surface is characterized by atomic force microscopy. The surface-enhanced Raman gene (SERGen) probes developed in this study can be used to detect DNA targets via hybridization to complementary DNA probes. The probes do not require the use of radioactive labels and have a great potential to provide both sensitivity and selectivity. The effectiveness of this approach and its application in cancer gene diagnostics (BRCA1 breast cancer gene) are investigated.     

Toward virtual biopsy through an all fiber optic ultrasonic miniaturized transducer: a proposal

The present generation of devices based on opto-acoustic and acousto-optic conversion lets us foresee the possibility of realizing complete miniaturized transmitting-receiving transducers, able to generate and detect wideband ultrasounds by laser light. In the present paper, a miniaturized ultrasonic transducer entirely based on fiber optic technology is proposed. Such a device springs from the conjunction between our research, which has produced a highly efficient fiber optic opto-acoustic source, with the results obtained by other researchers concerning the realization of an ultrasonic receiver based on optical interferometry. Making use of the thermo-elastic effect for ultrasound generation, a source of ultrasound can be obtained by coupling a fiber optic to pulsed laser, if a film capable of absorbing laser light is placed onto fiber end. Starting from these remarks, we propose an efficient opto-acoustic source, able to generate pressure pulses with amplitude of the order of 10(4) Pa and bandwidth extending up to 40 MHz and beyond by using graphite materials as absorbing film. This solution makes use of a low-power pulsed laser as optical source possible. An ultrasonic receiving element was realized placing a Fabry-Perot cavity over the tip of a fiber optic. The cavity thickness modulation induced by ultrasonic beam is detected by an interferometer optical technique. We have realized a prototype of a receiving device that exhibits a sensitivity comparable with that of piezoelectric devices (10-100 nV/Pa) and an almost flat bandwidth extending up to 20 MHz or more. The extreme miniaturization of the resulting ultrasonic transducer, together with its wide ultrasonic frequency bandwidth, is the first step toward ultrasonic tissue biopsy. In this paper, before discussing the problem of constructing a complete ultrasonic transducer composed by a transmitter and receiver, the results carried out in these fields during the last decade are reviewed.     

Numerical Modeling of Inclusion Removal in Electromagnetic Stirred Steel Billets

To investigate the inclusion removal in billets cast under electromagnetic stirring (EMS) influence, a numerical model has been developed to compute the magnetic field, the Lorentz force, the steel flow velocities, and the particle transport within the liquid pool. The electromagnetic field was described by the Maxwell equations and the finite element method was applied using a commercial package. The turbulent fluid flow was described by the Navier‐Stokes equation and by the Reynolds Stress model and the finite volume method was applied using another numerical package. The time average of the Lorentz force was calculated in each element center and this value was applied as a body force in the Navier‐Stokes equation. The magnetic flux density profile was compared with the data obtained in the stirrer of the steel plant. The particle transport model includes the drag force, the buoyancy force and the random walk model, to include the turbulence effects on the particle trajectory. The inclusion removal was calculated and analysed in function of casting speed and stirring current for one size section of mold. The inclusions considered in the calculations have a fixed density and four values of diameter. The numerical results of the electromagnetic model are in agreement with the experimental measurements. A good relationship between the electromagnetic model and the fluid flow model could be shown. An interesting effect is the break of the rotation motion due to the EMS by the jet from the nozzle. The fraction of inclusions removed by the top surface of the mold was improved due to the EMS.     

Piezoelectric properties of Bi4Ti3O12 thin films annealed in different atmospheres

Bismuth titanate (Bi₄Ti₃O₁₂—BIT) films were evaluated for use as lead-free piezoelectric thin-films in micro-electromechanical systems. The films were grown by the polymeric precursor method on Pt/Ti/SiO₂/Si (1 0 0) (Pt) bottom electrodes at 700 °C for 2 h in static air and oxygen atmospheres. The domain structure was investigated by piezoresponse force microscopy (PFM). Annealing in static air leads to better ferroelectric properties, higher remanent polarization, lower drive voltages and higher piezoelectric coefficient. On the other hand, oxygen atmosphere favors the imprint phenomenon and reduces the piezoelectric coefficient dramatically. Impedance data, represented by means of Nyquist diagrams, show a dramatic increase in the resistivity for the films annealed in static air atmopshere.     

Industrial capacity planning in oligopolistic markets

Available productive capacity is determinant of a company’s success once it allows meeting the current and future demand. This article proposes a quantitative model for determining long-term productive capacity in competitive oligopolistic markets, based on the Nash Equilibrium formulated as a Variational Inequality problem. Numerical examples enable an analytical evaluation of the economic equilibrium’s sensitivity to marginal costs, investment costs, hurdle rate, and market saturation. Results show that, in order to achieve a greater market share, it is important to adopt strategies that reduce marginal costs. On the other hand, variations in the hurdle rate may or may not reinforce the position of a competitor in the market and his interest in investing in capacity expansion. Additionally, market saturation may be achieved, beyond which investment becomes unattractive. Each of these is a positive outcome for society, triggering diversified investments and competition in economic sectors where competition is low and profits are high.     

A PROPOSAL FOR A KNOWLEDGE MARKET BASED ON QUANTITY AND QUALITY OF KNOWLEDGE

Autonomous market environments have been proposed in the literature as the future of electronic markets. The ability to delegate complex negotiation processes and obtain similar or better results than their human counterparts has generated a great interest in agent-based markets. More recently, such a paradigm has been applied in the field of knowledge management and, more specifically, to knowledge sharing and exchange; however, most of the knowledge market proposals in the literature fail to give details on a key component of their models: knowledge quality. This article presents a new proposal for an agent-based market environment that aims at filling the previously mentioned gap in research. The main contribution of our research is the integration of formal mechanisms for knowledge quality and quantity measurement and the use of these values to set a price for knowledge and select the most suitable agent for negotiation.