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Mathematical Techniques (mathematical + techniques)

Distribution by Scientific Domains
Business, Economics, Finance and Accounting27%
Mathematics and Statistics18%
Chemistry18%

Selected Abstracts

Crack opening displacement in plate with bonded repair patch

FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 6 2006
M. M. RATWANI
ABSTRACT Mathematical techniques are extended to compute crack opening displacements in a cracked plate with an adhesively bonded composite patch. The plate and the patch are considered as orthotropic materials. The problem is reduced to the solution of integral equations. A software program is written to compute shear stresses in adhesive, stress intensity factors in the plate and the crack openings at the centreline of the crack. The effects of adhesive thickness, adhesive modulus, patch thickness and plate thickness on crack openings are investigated. A test program is carried out to obtain crack opening displacements in plate with bonded patch. A good agreement with analytical predictions is obtained. The effects of patches bonded on one or both sides of a plate on stress intensity factors are evaluated. [source]

Mathematical techniques in crystallog­raphy and materials science.

ACTA CRYSTALLOGRAPHICA SECTION A, Issue 2 2005
Third edition.
First page of article [source]

Combining Economic and Conjoint Analysis to Determine Optimal Academic Services

DECISION SCIENCES JOURNAL OF INNOVATIVE EDUCATION, Issue 1 2004
Mona Whitley Howard
ABSTRACT In today's era of global competition, organizations must manage their functions and activities in a manner such that they are responsive to customers' needs and can provide excellence in service to the customer while also being efficient and cost conscious. These issues are extremely common in corporate organizations, but such concerns are equally relevant in service industries, including institutions of higher education. This study is conducted at a private, undergraduate institution of higher education. We utilize focus group evaluation and conjoint analysis combined with economic analysis in the form of a newly designed preferred utility economic cost diagram to pick the ideal services that should be provided to enrolled students at the institution. The package of ideal services accounts for preferred utility expressed by students and a new methodology (preferred utility function) to balance these against financial considerations to optimize services and financial gains for a college adult education program. This combination of focus groups and mathematical techniques can be easily employed by educational institutes. [source]

An Evaluation of the Cod Fishing Policies of Denmark Iceland and Norway

EUROCHOICES, Issue 3 2004
R. Arnason
Summary An Evaluation of the Cod Fishing Policies of Denmark, Iceland and Norway Many ocean fisheries are subject to a fundamental economic problem generally referred to as the common property problem. This problem manifests itself as excessive fishing fleets and fishing effort, depressed fish stocks and little or no profitability of the fishing activity, irrespective of the richness of the underlying marine resources. European fisheries represent some of the most dramatic examples of the common property problem. This article employs simple empirical models and recently developed mathematical techniques to examine the economic efficiency of three European fisheries, namely the Danish, Icelandic and Norwegian cod fisheries, The optimal harvesting policies for each of these fisheries are calculated. Comparing these optimal policies with actual harvests provides a measure of the relative efficiency in these three cod fisheries. The comparison confirms the widely held impression that the cod harvesting policies of ail three countries have been hugely inefficient in the past. Moreover, it appears that the inefficiency has been increasing over time. Only during the last few years of our data are there indications that this negative trend may have been halted. Somewhat more surprisingly, in spite of radically different fisheries management systems, we find relatively little difference in the level of stock over-exploitation between these three countries. Politiques compareées de pêhe à la morue au Danemark, en Islande et en Norvège Beaucoup de pêcheries océaniques sont confrontées au problème nique fondamental de la "propriété collective". Celui-ci se manifeste par des flottes de taille excessive, au service d' efforts de péche exagérés, qui aboutissent à détruire les stocks de poisson et la rentabilité des pécheries, en dépit de la richesse des ressources marines sousjacentes. Les pêcheries européennes constituent actuellement l'un des exemples les plus dramatiques des problèmes associés a la propriété collective. On présente ici un modèle empirique assez simple mais associéà de nouvelles techniques mathématiques récemment développé es pour mesurer l' efficacitééconomique de trois types de politiques de pêche à la morue, au Danemark, en Norvège et en Islande. On commence par calculer le volume optimal des prises pour chacun de ces pays. La comparaison entre le niveau optimal et le niveau réel des prises permet de mesurer le degré d' efficacité des politiques suivies. Elle permet de confirmer l'opinion largement répandue selon laquelle les politiques passées ont été extrêmement peu efficaces. En outre, il apparaît que l'inefficacité est croissante avec le temps. C'est seulement dans les toutes dernières années des séries de données que l' on observe un infléchissement de cette tendance négative. Enfin, et c'est le plus surprenant, on trouve peu de differences entre les trois pays en ce qui conceme le degré de surexploitation du stock, et cela, bien que les principes de gestion des pêcheries y soient entiArement différents. Eine Bewertung der Kabeljaufischereipolitik in Dänemark, Island und Norwegen ahlreiche Hochseefischereien tehen einem grundlegenden ftliehen Problem gegenüber, das allgemein als Problem des kollektiven Eigentums bezeichnet wird. Dieses Problem zeigt sich in übermäßig großen Fangflotten und beträchtlichem Fischereiaufwand, geschrumpften Fischbeständen und geringer oder fehlender Rentabilität der Fischerei; dabei ist die Höhe der Fischressourcen unbedeutend für das Problem. Die europäischen Fischereien stellen einige der drastischsten Beispiele für das Problem des kollektiven Eigentums dar. In diesem Beitrag werden einfache empirische Modelle und kürzlich entwickelte mathematische Verfahren angewendet, um die wirtschaftliche Effizienz von drei europäischen Fischereien zu untersuchem der dänischen, der isländischen und der norwegischen Kabeljaufischerei. Für jede dieser Fischereien wird die optimale Nutzungsstrategie berechnet. Aus dem Vergleich dieser optimalen Nutzungsstrategie mit den tatsächlichen Erträgen ergibt sich ein Maß fur die relative Effizienz, die bei diesen drei Kabeljaufischereien vorliegt. Der Vergleich bestätigt den weit verbreiteten Eindruck, dass die Strategien zum Kabeljaufang in alien drei Ländern in der Vergangenheit enorm ineffizient waren. Darüber hinaus wird deutlich, dass die Ineffizienz im Laufe der Zeit zugenommen hat. Lediglich die Daten der letzten jahre enthalten Hinweise darauf, dass dieser negative Trend zum Stillstand gekommen sein könnte. Obwohl sich die Fischwirtschaft in jedem dieser drei Länder sehr stark unterscheidet, lassen sich erstaunlich wenige Unterschiede im Maß der Übernutzung des Fischbestandes finden. [source]

Competitive On-line Statistics

INTERNATIONAL STATISTICAL REVIEW, Issue 2 2001
Volodya Vovk
Summary A radically new approach to statistical modelling, which combines mathematical techniques of Bayesian statistics with the philosophy of the theory of competitive on-line algorithms, has arisen over the last decade in computer science (to a large degree, under the influence of Dawid's prequential statistics). In this approach, which we call "competitive on-line statistics", it is not assumed that data are generated by some stochastic mechanism; the bounds derived for the performance of competitive on-line statistical procedures are guaranteed to hold (and not just hold with high probability or on the average). This paper reviews some results in this area; the new material in it includes the proofs for the performance of the Aggregating Algorithm in the problem of linear regression with square loss. Résumé Cet article décrit une approch nouvelle à modelage statistique combinant les techniques mathematiques de statistique Bayesienne avec la philosophie de la theorie de algorithmes compétitives en ligne. Dans cette approche, qui émergeait durant le décennie derniére dans I'informatique, on ne suppose pas que les données sont produites par une mécanaisme stochastique; au lieu de cela, il est prouvé que les procédures statistiques compétitives en ligne atteignent toujours (et non, par exemple, avechaute probabilite) quelque but desirable (explicitant la bonne performance sur les données réeles). Cet article pass en revue des plusieurs résultats dans cette domaine; son matériel neuf comprend les preuves pour la performance de le àlgorithme agrégent dans le probléme de la régression linégression linéaire avec la perte carrée. [source]

On the volume of distribution at steady state and its relationship with two-compartmental models

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2008
James W.T. Yates
Abstract The volume of distribution at steady state is considered to be one of the primary pharmacokinetic measurements obtained from in vivo experiments. This quantity is quite commonly calculated using moments of the observed concentration curve, the process being referred to as noncompartmental analysis. In this paper the underlying assumptions of noncompartmental analysis are analysed with regard to the observed behaviour of models with two compartments: one of which has elimination from the central compartment, the other from the peripheral tissue compartment. This is in order to clarify the relationship between volume of distribution and clearance. It is shown that these two models are indistinguishable from measurements in blood. Furthermore relationships between the parameter values for the two models are given so that they produce the same observed profile. Expressions are derived in a novel way that relates the volume of distribution to these model rate constants. The definitions of clearance and volume of distribution at steady state are investigated using several different mathematical techniques, demonstrating the consistency of the derived expressions. It is shown, in a manner that the authors believe is a new approach, that when the assumption of central elimination does not apply, noncompartmental analysis will under estimate the volume of distribution, whereas clearance remains unchanged. This is compared quantitatively with respect to the volume predicted where central elimination holds, and is a result of an extended mean residence time. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:111,122, 2008 [source]

Notes on ferromagnetic p -spin and REM

MATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 7 2009
Adriano Barra
Abstract In this paper we apply some of the recent mathematical techniques (mainly based on interpolation) developed in the spin glass theory to the ferromagnetic p -spin model. We introduce two Hamiltonians and derive their thermodynamics. This is a second step toward an alternative and rigorous formulation of the statistical mechanics of simple systems on lattice. A first step has been performed in J. Stat. Phys. (2007; arXiv:0712.1344) where the techniques have been tested on the two-body Ising model. For completeness the adaptation of the well-known random energy model to the context of the ferromagnetism is presented. At the end a discussion on the extension of these techniques to Gaussian-disordered p -spin models is also briefly outlined. Copyright © 2008 John Wiley & Sons, Ltd. [source]

FORMALIZING WIESER's THEORY OF DISTRIBUTION: CONSISTENT IMPUTATION IN ALTERNATIVE THEORETICAL PERSPECTIVES

METROECONOMICA, Issue 2 2005
Arrigo OpocherArticle first published online: 18 MAY 200
ABSTRACT Wieser's theory of value and distribution has been formalized and interpreted mainly in the framework of efficient allocation of scarce resources. To this end, the mathematical techniques of linear programming have been used by such authors as Samuelson and Uzawa. This paper presents briefly what may be called the Knight,Samuelson,Uzawa formalization and supplements it with different proposed formalizations of some further aspects consistently developed in Wieser's works. The formalization that we propose concerns Wieser's theory of interest and his theory of value for ,cost goods'. It is argued that in such cases the produced means of production, and not the endowments of scarce resources, are at the centre of Wieser's analysis. It is shown that some appropriately specified models in the Sraffa,von Neumann,Leontief tradition can very usefully be employed in order to strengthen Wieser's intuitive arguments and give them a sound analytical structure. [source]

ON AXISYMMETRIC TRAVELING WAVES AND RADIAL SOLUTIONS OF SEMI-LINEAR ELLIPTIC EQUATIONS

NATURAL RESOURCE MODELING, Issue 3 2000
THOMAS P. WITELSKI
ABSTRACT. Combining analytical techniques from perturbation methods and dynamical systems theory, we present an elementaryapproach to the detailed construction of axisymmetric diffusive interfaces in semi-linear elliptic equations. Solutions of the resulting non-autonomous radial differential equations can be expressed in terms of a slowlyvarying phase plane system. Special analytical results for the phase plane system are used to produce closed-form solutions for the asymptotic forms of the curved front solutions. These axisym-metric solutions are fundamental examples of more general curved fronts that arise in a wide variety of scientific fields, and we extensivelydiscuss a number of them, with a particular emphasis on connections to geometric models for the motion of interfaces. Related classical results for traveling waves in one-dimensional problems are also reviewed briefly. Manyof the results contained in this article are known, and in presenting known results, it is intended that this article be expositoryin nature, providing elementarydemonstrations of some of the central dynamical phenomena and mathematical techniques. It is hoped that the article serves as one possible avenue of entree to the literature on radiallysymmetric solutions of semilinear elliptic problems, especiallyto those articles in which more advanced mathematical theoryis developed. [source]

Using distributed optimal control in economics: A numerical approach based on the finite element method

OPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 5-6 2001
Elena Calvo Calzada
Abstract The finite element method is employed to transform a distributed optimal control problem into a discrete optimization problem which can be solved with standard mathematical techniques. We use distributed optimal control in order to determine the optimal selective logging regime of a privately owned non-homogeneous forest. This regime has become nowadays a standard approach for the management of public forest. However, resource economists still have not come forward yet with an economic model for this widely applied management technique and base their economic analysis of the optimal management of a homogeneous forest on a clear cutting regime utilizing the Faustmann,Pressler,Ohlin Theorem. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Atomic Force Microscopy as a Tool for Biomedical and Biotechnological Studies,

ARTIFICIAL ORGANS, Issue 5 2003
Geraldo Antônio Guerrera Cidade
Abstract: This work presents different applications in progress with the aid of the atomic force microscopy (AFM) technique for biomedical and biotechnological applications, comprising both the acquisition of three-dimensional images and spectroscopic force measurements, in the following systems: first, low-density lipoprotein (LDL),glycosaminoglycans; second, lectins-polysaccharides; third, mycobacterium leprae cellular wall and Vesicular Stomatites Virus (VSV) with fibronectin laminin, and lipidic membranes; fourth, DNA,complex; and fifth, actin, as well as the development of surface functionalizing protocols and image restoration by means of mathematical techniques. [source]