The discovery of hidden facial images in the paintings of Vincent Van Gogh and Paul Gauguin by using computer graphics enhancement techniques

For nine short weeks in 1888, Vincent Van Gogh and Paul Gauguin lived and worked together in the city of Arles. Using computer graphics enhancement analyses, some of the paintings they did during this period revealed hidden facial images. One full hidden figure in a painting by Van Gogh and five camouflaged facial images in the works of Paul Gauguin were uncovered using computer graphics techniques. With the exception of one painting by Gauguin, these concealed images have not been previously reported.     

Linear dimensionality reduction by maximizing the Chernoff distance in the transformed space

Linear dimensionality reduction (LDR) techniques are quite important in pattern recognition due to their linear time complexity and simplicity. In this paper, we present a novel LDR technique which, though linear, aims to maximize the Chernoff distance in the transformed space; thus, augmenting the class separability in such a space. We present the corresponding criterion, which is maximized via a gradient-based algorithm, and provide convergence and initialization proofs. We have performed a comprehensive performance analysis of our method combined with two well-known classifiers, linear and quadratic, on synthetic and real-life data, and compared it with other LDR techniques. The results on synthetic and standard real-life data sets show that the proposed criterion outperforms the latter when combined with both linear and quadratic classifiers.     

A Bayesian alternative to parametric hypothesis testing

Summary A unified approach to parametric hypothesis testing from a decision-theoretical viewpoint is proposed. A measure of the discrepancy between two models is incorporated as part of the utility function. Specifically, the Kullback logarithmic divergence is considered as such a measure. Under certain conditions, when using this measure of discrepancy there is correspondence with the classical solutions.     

New BIST Schemes for Structural Testing of Pipelined Analog to Digital Converters

Two alternative BIST schemes are proposed for structural testing of pipelined Analog-to-Digital Converters (ADC). They are oriented to fault detection in the converter stages rather than to measure the whole ADC electrical performance parameters. The operational principle of both strategies relies on testing every ADC stage reconfigured as an A/D-D/A block and applying as input a simple DC stimuli set which is easily obtained, without strong precision requirements, by a resistive network. The main differences between both strategies relate to the way the output response is evaluated. In the BIST#1 scheme, analog and digital outputs are compared with reference levels generated with a reference D/A converter and a counter. In the BIST#2 strategy, only digital outputs are available and they are compared with fault-free values previously stored in an on-chip register. The new techniques are intended to be used in pipelined converters of an arbitrary number of conversion stages and with a digital self-correction mechanism.     

Mild Stereoselective Intermolecular Acetoxylation and Azidation of α‐C−H Bonds in Tröger's Bases

Introduction of oxygen and nitrogen into organic molecules is one of the fundamental strategies for their functionalization. Traditional approaches rely on the formation of an activated intermediate, which is then modified in a subsequent step. Here we report a simple direct oxidative α‐acetoxylation and azidation of α‐C−H bonds in Tröger's base analogues promoted by N‐bromosuccinimide (NBS) and palladium(II)acetate [Pd(OAc)₂] under mild conditions. This approach is pivotal on NBS oxidizing the carbon atoms next to the nitrogen atoms in the presence of Pd(OAc)₂ followed by a reaction with oxygen‐ or nitrogen‐centred nucleophiles such as KOAc or NaN₃ to yield either the mono‐ and bisacetoxylated or azidated Tröger's base derivatives in a stereo‐ and chemoselective manner. The obtained products can be efficiently modified to access synthetically meaningful structures.

     

Magnesium substitution in brushite cements

The use of magnesium-doped ceramics has been described to modify brushite cements and improve their biological behavior. However, few studies have analyzed the efficiency of this approach to induce magnesium substitution in brushite crystals. Mg-doped ceramics composed of Mg-substituted β-TCP, stanfieldite and/or farringtonite were reacted with primary monocalcium phosphate (MCP) in the presence of water. The cement setting reaction has resulted in the formation of brushite and newberyite within the cement matrix. Interestingly, the combination of SAED and EDX analyses of single crystal has indicated the occurrence of magnesium substitution within brushite crystals. Moreover, the effect of magnesium ions on the structure, and mechanical and setting properties of the new cements was characterized as well as the release of Ca^2 + and Mg^2 + ions. Further research would enhance the efficiency of the system to incorporate larger amounts of magnesium ions within brushite crystals.     

Ground Movements around Corners of Excavations: Empirical Calculation Method

This paper presents an empirical methodology that allows calculation of ground displacements behind corners of retained cut excavations. The increased stiffness of a retaining wall at the corner of an excavation normally leads to a corresponding reduction in ground movements behind the retaining wall. These “corner effects” derived from retained cut excavations can only be assessed at present by using three-dimensional numerical analysis or empirical methods. Significant cost and time can be taken carrying out three dimensional analysis, which, additionally, is not normally carried out at an early stage of the design of a project. Furthermore, numerical analysis must be undertaken by a competent person with appropriate training. An inappropriate analysis can yield to misleading and counterproductive results. This constitutes an expensive requirement on practitioners that often resort to more conservative designs which ignore corner effects. The methodology of adjusting calculated ground movements around corners of excavations described in this paper is simple to use and easy to program into software or spreadsheets. It can be used in conjunction with two-dimensional numerical analysis and also for calculating displacements in early stages of projects when numerical analysis has not yet been undertaken. This allows for more informed early discussion with third parties where approvals are sought on a given project.     

Tests lineales para contrastes con hipotesis oblicuas

Resumen En contrastes de hipótesis oblicuas para medias normales se ha demostrado la dominación del test de razón de verosimilitud (TRV). En este contexto consideramos estadísticos definidos por combinaciones lineales de las medias muestrales obteniendo test para coeficientes fijos y aleatorios. En ambos casos los test óptimos no tienen en cuenta toda la información del modelo original siendo adecuados para situaciones con hipótesis menos restrictivas. En la obtención de tests con coeficientes aleatorios se detectan anomalías al utilizar el estimador máximo verosímil. Parcialmente financiado por la DGICYT PB87-0905-C02-01.     

Industrial uses of geothermal energy a framework for application in a developing country

This paper presents a model of approach for agroindustrial development utilizing geothermal energy in an agriculturally based tropical developing country. Presented is the complexity of patterns in raw materials productivity, demand and the present problems of preserving their quality from biological deterioration thru drying.Utilization of a geothermal agroindustrial estate have to be carefully studied and programmed in reply to an almost constant heat demand profile consistent with seasonal available raw materials. This study uses the Tongonan Geothermal Field in Leyte Island as the model for presentation.     

Low-cost BSA technique for threshold-logic gate based multiplierimplementations

A technique is presented for implementing multipliers based on threshold gates. It introduces a new approximation to solve the most expensive step in the block save addition (BSA) approach for multiplier implementations. The order of complexity of the relevant parameters in the proposed solution is substantially reduced when compared with previous realisations of the same multiplication algorithm