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A novel technique to predict the manufacturing process-induced distortions and deformations in thick unidirectional carbon fiber reinforced plastics laminates is detailed in this article. An integrated numerical model is developed to account for non-isothermal resin flow, related compaction, transient resin cure, and resin shrinkage effects to predict the final shape of the autoclave cured thick prepreg laminate. The associated physics are mathematically coupled to solve for the process variables interactively. The results illustrate reduction in the thickness of the laminate prior to the start of curing when initial fiber volume fractions are pre-set. This confirms that the initial transverse deformation of B-stage prepreg is due to the applied vacuum and/or pressure. Once curing initiates, deformation of the laminate due to compaction increases, proportionally, with the increase in fiber volume fraction. Furthermore, the thermo-chemical residual strains contribute to additional compaction. The final distorted shape observed in simulation of the originally flat laminate matches with the shape of the fabricated laminate with 6.6 mm thickness. A solution to minimize the distortion is discussed in detail. This procedure is extended to simulate a curved laminate’s processing; where, the shear moduli were observed to influence the final shape of the laminate. The findings are presented and deliberated in this article. [ABSTRACT FROM AUTHOR]

Fixtures are an essential element of the machining system, being part of the precision path and force flux between process and machine tool. Intelligent fixtures enable the identification of critical process conditions, a compensation of error influences and the minimization of defective parts. At first, this contribution presents a study in which the influence of the clamping setup and of the workpiece characteristics at various steps of the machining process is analyzed. Experimental and theoretical results regarding the dynamic process behavior reveal the relevance of these influences with respect to machining performance and workpiece quality. Secondly, the European research project INTEFIX is introduced. Representative approaches of intelligent fixtures, reducing workpiece vibrations and distortions, and improving workpiece alignment, are described and prototypes are shown. In a third part, two examples of intelligent fixtures are presented and discussed more in detail. The first example concerns a fixture for the identification and active mitigation of chatter in milling of thin walled workpieces. The second example is related to the compensation of workpiece distortions which occur in machining of large thin walled structural parts. [ABSTRACT FROM AUTHOR]

Face recognition is an important security task. We propose a high-level method to solve this problem: a permutation coding neural classifier (PCNC). A PCNC with a special feature extractor for face image recognition systems is a relatively new method that has been tested with good results to classify real environment images (such as larvae of various types and handmade elements). As baseline methods, a support vector machine (SVM) and the iterative closest point (ICP) method are selected for comparison. We applied these methods to gray-level images from the FRAV3D face database. Fifteen experiments were performed to examine a large set of training and testing conditions. As a general result, it was observed that errors are lower with the PCNC than with the SVM and the ICP classifier. We aggregated various distortions for the initial images to improve the PCNC. We analyze and discuss the obtained results. [ABSTRACT FROM AUTHOR]

The acquisition of images with different modalities may involve different alterations with respect to an ideal model. Inhomogeneous brightness and contrast, blur due to non-ideal focusing, distortions are common. It is proposed herein to account for such effects for instance by registering a calibration target image with an actual optical image to measure lens distortions. An Integrated Digital Image Correlation (I-DIC) algorithm is proposed to account for the above artifacts and the algorithm is detailed. The resolution and uncertainty of the technique are first investigated on synthetic images, and then applied to the measurement of distortions for infrared (IR) images. The procedure is shown to reduce drastically the residual level assessing the validity of the image formation model, but more importantly allowing for a much improved registration of images. [ABSTRACT FROM AUTHOR]

Absolute Mean Brightness Error (AMBE) and entropy are two popular Image Quality Analyzer (IQA) metrics used for assessment of Histogram Ecpialization (HE)-based contrast enhancement methods. However, recent study shows that they have poor correlation with Human Visual Perception (HVP); Pearson Correlation Coefficient (PCC)<0.4. This paper, proposed a new IQA which takes into account important properties of HVP with respect to luminance, texture and scale, evaluation results show that the proposed IQA has significantly improved performance (PCC>0.9). It outperforms all IQAs in study, including two prominent IQAs designed for assessment of image fidelity in image coding-Multi-Scale Structural Similarity (MSSIM) and information fidelity criterion. [ABSTRACT FROM AUTHOR]

The crystal structure of ferrous glycine sulfate (a ferroglycine sulfate complex with chemical formula FeSO4(C2H5NO2), a compound extensively used as an iron dietary supplement, was refined from synchrotron X-ray powder diffraction data. The crystal structure of an (so-far unreported) isostructural manganese analogue was also structurally detailed by a Rietveld refinement against the corresponding X-ray powder diffraction pattern. All studied compounds crystallize in the monoclinic P21 space group, building layers of metal cations coordinated by the oxygen atoms of sulfate groups and glycine ligands. Neighboring layers are parallel packed, bonded by hydrogen bonds. The coordination polyhedra around the cations can be regarded as distorted and elongated octahedral, presumably due to severe strains present in the crystal structure of the layers. [ABSTRACT FROM AUTHOR]

Several studies have shown that the perception of one's own hand size is distorted in proprioceptive localization tasks. It has been suggested that those distortions mirror somatosensory anisotropies. Recent research suggests that non-corporeal items also show some spatial distortions. In order to investigate the psychological processes underlying the localization task, we investigated the influences of visual similarity and memory on distortions observed on corporeal and non-corporeal items. In experiment 1, participants indicated the location of landmarks on: their own hand, a rubber hand (rated as most similar to the real hand), and a rake (rated as least similar to the real hand). Results show no significant differences between rake and rubber hand distortions but both items were significantly less distorted than the hand. Experiments 2 and 3 explored the role of memory in spatial distance judgments of the hand, the rake and the rubber hand. Spatial representations of items measured in experiments 2 and 3 were also distorted but showed the tendency to be smaller than in localization tasks. While memory and visual similarity seem to contribute to explain qualitative similarities in distortions between the hand and non-corporeal items, those factors cannot explain the larger magnitude observed in hand distortions. [ABSTRACT FROM AUTHOR]

Structural weight is one of the key criteria for vessels used in marine industries. The use of stiffeners and stringers strengthens the structure with the addition of a minimum weight. In cylindrical pressure vessels under hydrostatic pressure, mostly ring-type stiffeners are used. In order to join a stiffener ring to the vessel, welding is a conventional method. However, this process generates welding residual stresses and distortions, which can be added to external loads and cause structural failure. This study aims to develop a comprehensive simulation tool to predict distortions and residual stresses generated due to fillet-welded stiffener ring on an aluminum cylinder. Therefore, a hybrid numerical simulation approach has been employed. The simulation strategy has been implemented by using finite element software ANSYS enhanced with a number of subroutines. Results showed that the stiffener ring changes distortion trend in all orientation, especially in the radial direction with a reduction up to 15% in stiffener ring position. On the other hand, the radial residual stress was negligible and the hoop residual stress was tensile in the fillet weld region, with half of the base metal tensile strength magnitude, except in the start and the end of weld. Moreover, the axial residual stresses in the weld region on inner and outer surface of vessel in stiffener ring position were tensile and compressive, respectively. [ABSTRACT FROM AUTHOR]

The governments of Ghana and public sector workers have since the country’s independence, well over fifty years ago, been embroiled in a protracted fisticuff all in their quest for a rewarding compensation package that will adequately recompense the latter for the physical and mental efforts they exert at their various places of work. The road to finding a lasting solution to this brawl has been tortuous, bumpy and chequered. Commissions upon commissions have been instituted to among other issues, advise the government on the effective ways of rewarding the country’s labour to stem the tide of labour agitations for an enhanced, equitable and rewarding compensation regime, but this single laudable objective has never been attained. Incessant strikes, threats of strikes and storms of protests continue to greet every government that assumes political power in Ghana. Hardly a year goes passed without a group of labour unions issuing such threats or embarking upon work stoppage either to demonstrate their dissatisfaction with government’s lackadaisical attitude to the implementation of one public sector salary regime or to demand for enhanced remuneration package. The real solution to this age-long problem continues to elude the country. The single-spine pay policy (SSPP), which was touted to be a panacea for the craved for rewarding compensation by Ghana labour has failed to suffice to whet the appetite of public sector workers. So, where do we turn next? This paper traces various attempts both past and present governments have made to find a lasting solution to the protracted labour agitations for enhanced remuneration for a comprehensive, equitable and rewarding compensation package for the public sector workers in Ghana. It enquires into other possible measures of solving the matrices of confronting the onslaught in the labour front to stem the tide of agitations over wages and salaries. The data was obtained from both primary and secondary sources. The primary data comprises of reports by commissions and committees set up to review wages and salaries for the country’s public sector which is supported with information from existing literature on the subject.

Quantitative multiple criteria decision aid (MCDA) methods of evaluation gain increasing popularity among researchers. The idea of the methods is to comprise values ofcriteria characterising each object into a single non-dimensional cumulative criterion, which reflects attractiveness or position of the object in view of an objective chosen. Normalisation of weights is a compulsory procedure whenever criteria of different dimensions are present. There several methods of normalisation available. Nevertheless, each method may introduce distortions into transformed data. The paper is devoted to exploration of problems related to such distortions and reveals particular cases.

In the extended segment of -850 m main haulage way of Qujiang Mine, the development processes of plastic zone in soft rock roadway with high geo-stress has been analyzed by theoretical analysis method,numerical simulation method and other techniques.The five development stages of plastic zone take place successively, which are plastic dot, the formation of plastic annulus, the distortions of plastic annulus, the uneven development and malignant extension of plastic zone, respectively. The studies suggest that the partial distortion of plastic zone is a major cause for the malignant extensions of plastic zone. Only effectively control the partial distortion of plastic zone,and make the development of plastic zone tend to uniform as much as possible,then the stability of surrounding rocks would be achieved. According to the plastic zone control theory, the comprehensive support method with “bolt wire cable and shotcrete+floor anchor cable+local anchor cable or grouting reinforce” is presented and applied in the roadway. The monitor result at construction site shows that the general development of the plastic zone is uniform and the deformation of the surrounding rock is controlled well by the supports applied. [ABSTRACT FROM AUTHOR]

The World Trade Organization (WTO) Agreement on Agriculture was signed in June 1994. It accomplished two things: it brought agricultural trade under the rules of WTO, and it set schedules for reducing barriers to trade under the three pillars of liberalization--market access, export assistance, and domestic support. Nine years later there has been precious little liberalization. The new Doha Round has ambitious objectives for agricultural trade liberalization. However, given recent behavior by rich developed countries, it seems unlikely that developing countries will get increased access to Northern markets or reduced competition from subsidized exports, despite their now representing a majority of WTO members.

JEL: P21

In questa breve nota, l'autore sostiene che l'accento su tassi di cambio nominali fissi all'interno dello SME crea distorsioni gravi a patto che i tassi di inflazione non sono convergenti. In this brief note, the author argues that the emphasis on fixed nominal exchange rates inside the EMS creates severe distortions as long as inflation rates are not converging. JEL: E42, F36

We present an algorithm for automatically detecting and visualizing small non-local variations between repeating structures in a single image. Our method allows to automatically correct these variations, thus producing an 'idealized' version of the image in which the resemblance between recurring structures is stronger. Alternatively, it can be used to magnify these variations, thus producing an exaggerated image which highlights the various variations that are difficult to spot in the input image. We formulate the estimation of deviations from perfect recurrence as a general optimization problem, and demonstrate it in the particular cases of geometric deformations and color variations. [ABSTRACT FROM AUTHOR]

Over the past few years, reversible watermarking techniques for relational databases have been proposed to provide protection of ownership rights, data tempering, and data integrity. Mainly, these techniques ensure original data recovery from watermarked data, whereas irreversible watermarking schemes only protect ownership rights. This characteristic of reversible watermarking has emerged as a candidate solution for the protection of ownership rights of data, intolerable to modifications such as medical data, genetic data, credit card, and bank account data. The main objective of this paper is to make an extensive survey of the state-of-the-art in reversible watermarking techniques for relational databases to reflect recent research progress and to point out the key issues for future research. In order to analyze these techniques, a classification has been performed on the basis of (i) the extent of modifications introduced by the watermarking scheme in the underlying data and (ii) the robustness of the embedded watermark against malicious attacks. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

What is the value of a financial instrument in an illiquid market? The classical valuation theory which is based on the law of one price assumes implicitly that market participants can trade freely in both directions at the same price. In the absence of perfect liquidity the law of one price should be replaced by a two price theory where the terms of trade depend on the direction of the trade. A static as well as a continuous time theory for two price economies is discussed. The two prices are termed bid and ask or lower and upper price but they should not be confused with the vast literature relating bid-ask spreads to transaction costs or other frictions involved in modeling financial markets. The bid price arises as the infimum of test valuations given by certain market scenarios whereas the ask price is the supremum of such valuations. The two prices correspond to nonlinear expectation operators. Specific dynamic models which are driven by purely discontinuous Lévy processes are considered. This article emerged from papers written jointly with D. Madan, M. Pistorius, W. Schoutens and M. Yor (2014) [9,10]. [ABSTRACT FROM AUTHOR]

Copyright of Problems of Economy is the property of Research Centre for Industrial Developmen Problems of Nas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ABSTRACT Tax distortions cause a trade-off between efficiency and equity. However, taxes not only affect incentives; they also provide implicit insurance, and this may critically affect the efficiency-equity relationship. For a standard labour supply problem it is shown that the insurance effect mutes the sensitivity of labour supply to taxes, which tends to reduce tax distortions and lower the marginal costs of public funds. The relation between incentives and insurance and thus efficiency and equity is flattened by the insurance effect and it may even be non-monotone. However, the optimal utilitarian policy implies that there is always a trade-off between efficiency and equity on the margin. [ABSTRACT FROM AUTHOR]

An attempt has been made to investigate the influence of various weld parameters on the dynamic behavior of rotating bowl and thereby optimizing those parameters for the improved performance of the same. The welding input parameters play a significant role in the final distortions, which in turn cause the unbalanced mass and eccentricity, thus affecting the dynamic stability of rotor. In this regard, a synergistic approach is followed involving both finite element modeling using a coupled thermo-mechanical analysis and experimental work for estimating the induced distortion during welding. The dynamic behavior is studied comprehensively through numerical analysis by introducing the obtained distortions on the surface of the bowl after welding for different conditions such as welding speed, clamping conditions and weld sequence. [ABSTRACT FROM AUTHOR]

This paper presents a new frequency estimator algorithm for electric power systems that uses the Mathematical Morphology operators of dilation and erosion to predict the Clarke Components from voltage signals of three phases of the system. The frequency is obtained as a function of phase shift between the predicted complex signal and the received complex signal given by the αβ-Transformation. The proposed method presented great accuracy and fast convergence for a wide range of different operational conditions involving transitory events of frequency deviation, amplitude variations, signal phase shifts and stable power swings. In addition, signals distorted by noises, harmonics and inter-harmonics were also tested. In order to demonstrate the quality of the new frequency estimator in each analyzed case, its estimation was compared with the responses obtained by four other methods, in terms of performance indices based on the estimation of transitory error and response convergence time. For all analyzed cases, the proposed methodology presented better results, showing great robustness and high accuracy for its task. [ABSTRACT FROM AUTHOR]

Nitriding is a thermochemical process that is used to improve the fatigue life of structural parts. It also involves residual stresses and non-negligible distortions of treated parts. This work deals with a pre-dimensioning tool able to simulate distortions of complex parts, generated during treatment. The presented model uses the analogy between diffusion of species and heat conduction to describe development of apparent volumic eigenstrains of the treated material, which is the source of global part distortions. The first step of the model consists in identifying these apparent volumic eigenstrains using experimental distortion measurements of a nitrided sample. Then, the unstationnary equivalent boundary condition of an equivalent diffusion problem is developed in order to numerically generate the volumic strains previously identified. Finally, this equivalent boundary condition is integrated in a heat conduction finite element code to simulate distortions of parts with complex geometries. In case of an industrial sample, the predicted distortions are compared to experimental measurements performed on a 3D coordinate measuring machine. The presented tool allows evaluating the consequences of a design choice on the final part distortions induced by the treatment. [ABSTRACT FROM AUTHOR]

The effect of zinc ions (Zn) on the structure, morphology and optical properties of (CaZn)WO microcrystals with ( x = 0, 0.01, 0.02, and 0.03) obtained by the microwave-hydrothermal method at 170 °C for 1 h is reported in this letter. These microcrystals were characterized by X-ray diffraction (XRD), Rietveld refinement, energy dispersive X-rays spectroscopy (EDXS) and field emission scanning electron microscopy (FE-SEM) images. The optical properties were investigated by ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy and photoluminescence (PL) measurements. XRD patterns and Rietveld refinement data indicated that all the (CaZn)WO microcrystals present a tetragonal structure and a reduction of lattice parameters and unit cell volume occurs with the increase of Zn. EDXS data confirms that the elemental chemical composition was achieved for (CaZn)WO microcrystals. FE-SEM images showed that the replacement of Ca by the Zn promotes a reduction of average crystals size and considerable changes in crystal shape starting from dumbbell-like to decorative ball-like (CaZn)WO microcrystals. UV-Vis spectra evidenced a small increase in optical band gap values (from 5.72 to 5.76 eV). Finally, PL emission of (CaZn)WO microcrystals was improved until x = 0.02 due to the presence of defects at medium range and new intermediate electronic levels in the band gap associated to the Zn content. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

There are two main pitfalls for those who analyse Soviet-type economies: the difficulty of explaining macroeconomic relationships in terms of either neoclassical or Keynesian received theory and the distorted official data. It is systemic features that make the characteristic macro effects mean something different under central planning from what is understood by Western economists and generate quantity and price distortions that cause statistics in Soviet-type economies to differ from those in market economies. This paper sets these differences and distortions into an explanatory framework and, while received theory is applied, the impact of institutional differences is also taken into account. Empirical support for the framework is given with attention drawn to distortions in prices and especially quantities, since the latter are less evident. JEL: P21

In this brief note, the author argues that the emphasis on fixed nominal exchange rates inside the EMS creates severe distortions as long as inflation rates are not converging. JEL: E42, F36

When observing a scene by a perspective camera through multiple refractive planes (e.g. underwater imaging), distortions and illusions, mainly caused by the refractions occurring at the interfaces between the different mediums, will be brought into the imaging system. Traditional pin‐hole camera model becomes invalid in handling such case. A novel general camera model is presented, which is in fact a virtual pixel‐wise varifocal model and can be used to encode multilayer refractions effectively. The model is built up based on two important findings. One is that the air between the camera centre and the nearest layer can be modelled as an air layer. The other one is that a ray passing through the air layer and these multiple layers causes only lateral displacement without changing its direction. The proposed camera model guarantees fast calculation of the backward projection. The forward projection equation is also derived and an efficient solving algorithm is proposed. Synthetic and real experiments are designed to verify the effectiveness and efficiency of the proposed theory. [ABSTRACT FROM AUTHOR]

This paper simulates the effects of three increasingly bolder reforms in the Colombian social protection system: the equalization of salaried and self-employed labor contributions; the removal of payroll taxes, parafiscales ; and the complete delinking of social protection benefits from labor status. We collect nationally representative information concerning individual willingness to pay for several packages of social security benefits; identify and quantify – for the first time – three specific distortions caused by existing social security and social assistance systems; and simulate the gains that social protection reforms would bring about in terms of reduced labor distortions. We find that workers in Colombia, regardless of occupation, have a very similar willingness to pay for the full insurance package – below 20% of their labor earnings – and very similar valuation of social protection services – about 50% below par. Labor distortions are large, as expected from very high labor costs, but we quantify an implicit formality tax and informality subsidy ranging between 2 and 27 percent of different representative workers’ earnings. Critically, the long-discussed reforms in Colombia – including the elimination of parafiscales – will not reduce substantially the multiple distortions in its labor market. [ABSTRACT FROM AUTHOR]

In what ways do native language (NL) speakers and foreign language (FL) learners differ in understanding the same messages delivered with or without gestures? To answer this question, seventh- and eighth-grade NL and FL learners of English in the United States and Norway were shown a video of a speaker describing, in English, a cartoon image that the viewers could not see. For half the viewers, the speaker's gestures were visible; for the others they were not. Participants drew a picture of each description, which was later coded for recall of explicit information, comprehension of logically implied information, and distortions. Overall, NL listeners produced the most accurate drawings; the presence of gestures did not appreciably facilitate NL comprehension. In contrast, the availability of gestures had a measurable effect on FL listener performance: It enabled them to produce drawings within native-like range. However, lack of gestures negatively impacted FL listener comprehension and recall. Regardless of condition, distortions in FL responses were significantly more frequent than in NL responses. All participants reported valuing visual cues in communication, yet their understanding of their value for their actual drawing performance was inconsistent, suggesting a difference between visual cue preference and visual cue dependence. [ABSTRACT FROM AUTHOR]