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Special Class (special + class)
Selected AbstractsConstruction and Optimality of a Special Class of Balanced DesignsQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 5 2006Stefano Barone Abstract The use of balanced designs is generally advisable in experimental practice. In technological experiments, balanced designs optimize the exploitation of experimental resources, whereas in marketing research experiments they avoid erroneous conclusions caused by the misinterpretation of interviewed customers. In general, the balancing property assures the minimum variance of first-order effect estimates. In this work the authors consider situations in which all factors are categorical and minimum run size is required. In a symmetrical case, it is often possible to find an economical balanced design by means of algebraic methods. Conversely, in an asymmetrical case algebraic methods lead to expensive designs, and therefore it is necessary to adopt heuristic methods. The existing methods implemented in widespread statistical packages do not guarantee the balancing property as they are designed to pursue other optimality criteria. To deal with this problem, the authors recently proposed a new method to generate balanced asymmetrical designs aimed at estimating first- and second-order effects. To reduce the run size as much as possible, the orthogonality cannot be guaranteed. However, the method enables designs that approach the orthogonality as much as possible (near orthogonality). A collection of designs with two- and three-level factors and run size lower than 100 was prepared. In this work an empirical study was conducted to understand how much is lost in terms of other optimality criteria when pursuing balancing. In order to show the potential applications of these designs, an illustrative example is provided. Copyright © 2006 John Wiley & Sons, Ltd. [source] Channel Coordination for a Supply Chain with a Risk-Neutral Manufacturer and a Loss-Averse Retailer,DECISION SCIENCES, Issue 3 2007Charles X. Wang ABSTRACT This articles considers a decentralized supply chain in which a single manufacturer is selling a perishable product to a single retailer facing uncertain demand. It differs from traditional supply chain contract models in two ways. First, while traditional supply chain models are based on risk neutrality, this article takes the viewpoint of behavioral principal,agency theory and assumes the manufacturer is risk neutral and the retailer is loss averse. Second, while gain/loss (GL) sharing is common in practice, there is a lack of analysis of GL-sharing contracts in the supply chain contract literature. This article investigates the role of a GL-sharing provision for mitigating the loss-aversion effect, which drives down the retailer order quantity and total supply chain profit. We analyze contracts that include GL-sharing-and-buyback (GLB) credit provisions as well as the special cases of GL contracts and buyback contracts. Our analytical and numerical results lend insight into how a manufacturer can design a contract to improve total supply chain, manufacturer, and retailer performance. In particular, we show that there exists a special class of distribution-free GLB contracts that can coordinate the supply chain and arbitrarily allocate the expected supply chain profit between the manufacturer and retailer; in contrast with other contracts, the parameter values for contracts in this class do not depend on the probability distribution of market demand. This feature is meaningful in practice because (i) the probability distribution of demand faced by a retailer is typically unknown by the manufacturer and (ii) a manufacturer can offer the same contract to multiple noncompeting retailers that differ by demand distribution and still coordinate the supply chains. [source] Property Derivatives for Managing European Real-Estate RiskEUROPEAN FINANCIAL MANAGEMENT, Issue 1 2010Frank J. Fabozzi G15; G20 Abstract Although property markets represent a large proportion of total wealth in developed countries, the real-estate derivatives markets are still lagging behind in volume of trading and liquidity. Over the last few years there has been increased activity in developing derivative instruments that can be utilised by asset managers. In this paper, we discuss the problems encountered when using property derivatives for managing European real-estate risk. We also consider a special class of structured interest rate swaps that have embedded real-estate risk and propose a more efficient way to tailor these swaps. [source] A natural neighbour Galerkin method with quadtree structureINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 6 2005J. J. Laguardia Abstract We describe in this paper a highly structured numerical method that allows for an important speedup in the calculations. The method is implemented in a bi-dimensional binary tree (quadtree or octree) structure in a partition of unity framework. The partition of unity is constructed by using natural neighbour interpolation. Data can be easily obtained from voxel or pixel-based images, as well as STL files or other CAD descriptions. The method described here possesses linear completeness at least and essential boundary conditions are implemented through the characteristic function method, by employing a special class of functions called R -functions. After the theoretical description of the method, some examples of its performance are presented and analysed. Copyright © 2005 John Wiley & Sons, Ltd. [source] Stability analysis and guaranteed domain of attraction for a class of hybrid systems: an LMI approachINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 5 2003S. Palomino Bean Abstract This paper presents sufficient conditions for the regional stability problem for switched piecewise affine systems, a special class of Hybrid Systems. This class of systems are described by an affine differential equation of the type x,=A(,)x+b(,), where x denotes the continuous state vector and , is a vector of logical variables that modifies the local model of the system in accordance with the continuous dynamics. Using a Lyapunov function of the type v(x)=x,P(x)x, we present LMI conditions that, when feasible, guarantee local stability of the origin of the switched system. Examples of switched affine systems are used to illustrate the results. Copyright © 2003 John Wiley & Sons, Ltd. [source] Survey of quantitative feedback theory (QFT),INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 10 2001Isaac Horowitz QFT is an engineering design theory devoted to the practical design of feedback control systems. The foundation of QFT is that feedback is needed in control only when plant (P), parameter and/or disturbance (D) uncertainties (sets ,,={P}, ,,={D}) exceed the acceptable (A) system performance uncertainty (set ,,={A}). The principal properties of QFT are as follows. (1) The amount of feedback needed is tuned to the (,,, ,,, ,,) sets. If ,, ,exceeds' (,,, ,,), feedback is not needed at all. (2) The simplest modelling is used: (a) command, disturbance and sensor noise inputs, and (b) the available sensing points and the defined outputs. No special controllability test is needed in either linear or non-linear plants. It is inherent in the design procedure. There is no observability problem because uncertainty is included. The number of independent sensors determines the number of independent loop transmissions (Li), the functions which provide the benefits of feedback. (3) The simplest mathematical tools have been found most use ful,primarily frequency response. The uncertainties are expressed as sets in the complex plane. The need for the larger ,,, ,, sets to be squeezed into the smaller ,, set results in bounds on the Li(j,) in the complex plane. In the more complex systems a key problem is the division of the ,feedback burden' among the available Li(j,). Point-by-point frequency synthesis tremendously simplifies this problem. This is also true for highly uncertain non-linear and time-varying plants which are converted into rigorously equivalent linear time invariant plant sets and/or disturbance sets with respect to the acceptable output set ,,. Fixed point theory justifies the equivalence. (4) Design trade-offs are highly transparent in the frequency domain: between design complexity and cost of feedback (primarily bandwidth), sensor noise levels, plant saturation levels, number of sensors needed, relative sizes of ,,, ,, and cost of feedback. The designer sees the trade-offs between these factors as he proceeds and can decide according to their relative importance in his particular situation. QFT design techniques with these properties have been developed step by step for: (i) highly uncertain linear time invariant (LTI) SISO single- and multiple-loop systems, MIMO single-loop matrix and multiple-loop matrix systems; and (ii) non-linear and time-varying SISO and MIMO plants, and to a more limited extent for plants with distributed control inputs and sensors. QFT has also been developed for single- and multiple-loop dithered non-linear (adaptive) systems with LTI plants, and for a special class (FORE) of non-linear compensation. New techniques have been found for handling non-minimum-phase (NMP) MIMO plants, plants with both zeros and poles in the right half-plane and LTI plants with incidental hard non-linearities such as saturation. [source] Semi-random LDPC codes for CDMA communication over non-linear band-limited satellite channelsINTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 4 2006Mohamed Adnan Landolsi Abstract This paper considers the application of low-density parity check (LDPC) error correcting codes to code division multiple access (CDMA) systems over satellite links. The adapted LDPC codes are selected from a special class of semi-random (SR) constructions characterized by low encoder complexity, and their performance is optimized by removing short cycles from the code bipartite graphs. Relative performance comparisons with turbo product codes (TPC) for rate 1/2 and short-to-moderate block sizes show some advantage for SR-LDPC, both in terms of bit error rate and complexity requirements. CDMA systems using these SR-LDPC codes and operating over non-linear, band-limited satellite links are analysed and their performance is investigated for a number of signal models and codes parameters. The numerical results show that SR-LDPC codes can offer good capacity improvements in terms of supportable number of users at a given bit error performance. Copyright © 2006 John Wiley & Sons, Ltd. [source] Biological,synthetic hybrid block copolymers: Combining the best from two worldsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2005Harm-Anton Klok Abstract Although biopolymers and synthetic polymers share many common features, each of these two classes of materials is also characterized by a distinct and very specific set of advantages and disadvantages. Combining biopolymer elements with synthetic polymers into a single macromolecular conjugate is an interesting strategy for synergetically merging the properties of the individual components and overcoming some of their limitations. This article focuses on a special class of biological,synthetic hybrids that are obtained by site-selective conjugation of a protein or peptide and a synthetic polymer. The first part of the article gives an overview of the different liquid-phase and solid-phase techniques that have been developed for the synthesis of well-defined, that is, site-selectively conjugated, synthetic polymer,protein hybrids. In the second part, the properties and potential applications of these materials are discussed. The conjugation of biological and synthetic macromolecules allows the modulation of protein binding and recognition properties and is a powerful strategy for mediating the self-assembly of synthetic polymers. Synthetic polymer,protein hybrids are already used as medicines and show significant promise for bioanalytical applications and bioseparations. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1,17, 2005 [source] The Effects of Uncertainty on the Demand for Health InsuranceJOURNAL OF RISK AND INSURANCE, Issue 1 2004atay Koç This article analyzes the effects of uncertainty and increases in risk aversion on the demand for health insurance using a theoretical model that highlights the interdependence between insurance and health care demand decisions. Two types of uncertainty faced by the individuals are examined. The first one is the uncertainty in the consumer's pretreatment health and the second is the uncertainty surrounding the productivity of health care. Comparative statics results are reported indicating the impact on the demand for insurance of shifts in the distributions of pretreatment health and productivity of health care in the form of first-order stochastic dominance, Rothschild,Stiglitz mean-preserving spreads, and second-order stochastic dominance. The demand for insurance increases in response to a Rothschild,Stiglitz increase in risk in the distribution of the pretreatment health provided that the health production function is in a special class and the price elasticity of health care is nondecreasing in the pretreatment health. Provided also that the demand for health care is own-price inelastic, the same conclusion is obtained when the uncertainty is about the productivity of health care. [source] Synchrotron techniques for metalloproteins and human disease in post genome eraJOURNAL OF SYNCHROTRON RADIATION, Issue 1 2004S. Samar Hasnain Metalloproteins make up some 30% of proteins in known genomes. Metalloproteins are a special class of proteins that utilise the unique properties of metal atoms in conjunction with the macromolecular assembly to perform life-sustaining processes. A number of metalloproteins are known to be involved in many disease states including ageing processes. The incorporation of the metal ion is a very tightly regulated process that, in vivo, very often requires specific chaperons to deliver and help incorporate the metal atom in the macromolecule. The lack of or inappropriate incorporation of metals along with genetic factors can lead to the mis-function of these proteins leading to disease. The mis-functions due to genetic alterations that lead to diseases like ALS (amyotrophic lateral sclerosis or motor neuron disease) and Creutzfeld Jacob disease (CJD) are now well recognised. Synchrotron radiation sources provide a unique set of structural tools, which in combination can prove extremely powerful in providing a comprehensive picture of these complex biological systems. In particular for metalloproteins, the combined use of X-ray crystallography, X-ray solution scattering and X-ray spectroscopy (XAFS) is extremely useful. We are currently engaged in a structural study where our aim is to characterize structurally and functionally metalloproteins and then transfer this knowledge to afford the problem of the mis-function of metalloproteins that lead to these terminal illnesses, either due to a gain of function/property or a loss of function/property. In this context, the benefits of adopting the `philosophy' being developed for the structural genomics effort are highlighted. [source] Stress-Driven Morphological Instabilities in Rocks, Glass, and CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2007M. A. Grinfeld The purpose of this study is to further investigate the classical Gibbs analysis of the heterogeneous system "stressed crystal,melt." It is demonstrated that each equilibrium configuration is stable with respect to a special class of variations introduced by Gibbs. This basic result is compared with the opposite result on the universal morphological instability of phase interface separating a stressed crystal with its melt. Some plausible manifestations of the instabilities implied by the Gibbs model are qualitatively discussed. [source] On the integral representation formula for a two-component elastic compositeMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 6 2006Miao-Jung Ou Abstract The aim of this paper is to derive, in the Hilbert space setting, an integral representation formula for the effective elasticity tensor for a two-component composite of elastic materials, not necessarily well-ordered. This integral representation formula implies a relation which links the effective elastic moduli to the N -point correlation functions of the microstructure. Such relation not only facilitates a powerful scheme for systematic incorporation of microstructural information into bounds on the effective elastic moduli but also provides a theoretical foundation for inverse-homogenization. The analysis presented in this paper can be generalized to an n -component composite of elastic materials. The relations developed here can be applied to the inverse-homogenization for a special class of linear viscoelastic composites. The results will be presented in another paper. Copyright © 2005 John Wiley & Sons, Ltd. [source] General theory of domain decomposition: Indirect methodsNUMERICAL METHODS FOR PARTIAL DIFFERENTIAL EQUATIONS, Issue 3 2002Ismael Herrera Abstract According to a general theory of domain decomposition methods (DDM), recently proposed by Herrera, DDM may be classified into two broad categories: direct and indirect (or Trefftz-Herrera methods). This article is devoted to formulate systematically indirect methods and apply them to differential equations in several dimensions. They have interest since they subsume some of the best-known formulations of domain decomposition methods, such as those based on the application of Steklov-Poincaré operators. Trefftz-Herrera approach is based on a special kind of Green's formulas applicable to discontinuous functions, and one of their essential features is the use of weighting functions which yield information, about the sought solution, at the internal boundary of the domain decomposition exclusively. A special class of Sobolev spaces is introduced in which boundary value problems with prescribed jumps at the internal boundary are formulated. Green's formulas applicable in such Sobolev spaces, which contain discontinuous functions, are established and from them the general framework for indirect methods is derived. Guidelines for the construction of the special kind of test functions are then supplied and, as an illustration, the method is applied to elliptic problems in several dimensions. A nonstandard method of collocation is derived in this manner, which possesses significant advantages over more standard procedures. © 2002 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 18: 296,322, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/num.10008 [source] A special class of simple 24-vertex polyhedra and tetrahedrally coordinated structures of gas hydratesACTA CRYSTALLOGRAPHICA SECTION A, Issue 5 2010M. I. Samoylovich It is established that the eight-dimensional lattice E8 and the Mathieu group M12 determine a unique sequence of algebraic geometry constructions which define a special class of simple 24-vertex, 14-face polyhedra with four-, five- and six-edge faces. As an example, the graphs of the ten stereohedra that generate most known tetrahedrally coordinated water cages of gas hydrates have been derived a priori. A structural model is proposed for the phase transition between gas hydrate I and ice. [source] New features on the fragmentation patterns of homoisoflavonoids in Ophiopogon japonicus by high-performance liquid chromatography/diode-array detection/electrospray ionization with multi-stage tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 15 2010Jin Qi Homoisoflavonoids, a special class of flavonoids, are mainly distributed in the Liliaceae family and have various biological activities. Previously, very little research has been reported on the gas-phase fragmentation patterns of homoisoflavonoids by electrospray ionization mass spectrometry. In this paper, we report the use of high-performance liquid chromatography with a diode-array detector (HPLC-DAD) and electrospray ionization multi-stage tandem mass spectrometry (ESI-MSn) to study the fragmentation behavior of 11 homoisoflavonoid standards and to analyze homoisoflavonoids in Ophiopogon japonicus. In total, 28 homoisoflavonoids (including seven novel constituents) were characterized. The deprotonated [MH], molecules of the homoisoflavonoids containing a saturated C2C3 bond afforded the A or B product ion (base peak) according to whether the B-ring was substituted with a hydroxyl group. For the homoisoflavonoids containing a C-2C-3 double bond, the product ions (A or C ion) were created from the precursor [MH], ion as the base peak when the B-ring was substituted with a hydroxyl group. The homoisoflavonoids carrying a formyl group in the A-ring readily eliminated one molecule of CO to form the product ion [M,+,HCO], (base peak) irrespective whether the C-2C-3 bond was saturated or not. This product ion afforded the [MHCOB-ringCH2,+,H], ion by cleavage of the C3C9 bond. This latter product ion always appeared in tandem mass (MS/MS) spectra of type I homoisoflavonoids. The common features of flavonoids observed during the gas-phase fragmentation mechanisms were the loss of the following groups: 15,Da (CH3), 18,Da (H2O), 28,Da (CO), 44,Da (CO2) and 46,Da (CH2O2). A retro-Diels-Alder (RDA)-like cleavage was also observed for the homoisoflavonoids. The different gas-phase fragmentation routes were characterized for the deprotonated molecules obtained from the various homoisoflavonoids and collision-induced dissociation (CID) fragmentation differences were noted for the different locations of the various substituents. In conclusion, we can say that this study allowed us to structurally elucidate and identify homoisoflavonoids distributed in related plants and their complex prescriptions. Copyright © 2010 John Wiley & Sons, Ltd. [source] Rotation designs: orthogonal first-order designs with higher order projectivityAPPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 3 2002Dizza Bursztyn Abstract In many factorial experiments, just a few of the experimental factors account for most of the variation in the response, a situation known as factor sparsity. Accurate modelling of the factor,response relationship may require use of higher-order terms in the active factors. In such settings, it may be desirable to use a design that is able, simultaneously, to screen out the important factors and to fit higher-order models in those factors. We derive a useful class of designs by rotating standard two-level fractional factorials. A special class of rotations is developed that has some appealing symmetry properties and can accommodate more factors than the rotation designs in Bursztyn and Steinberg (J. Stat. Plann. Inference 2001;97:399). A comparison of designs based on their projection properties and alias matrices shows that the new designs are better than many other alternatives. Copyright © 2002 John Wiley & Sons, Ltd. [source] Solutions to the nonlinear Schrödinger equation carrying momentum along a curveCOMMUNICATIONS ON PURE & APPLIED MATHEMATICS, Issue 9 2009Fethi Mahmoudi We prove existence of a special class of solutions to the (elliptic) nonlinear Schrödinger equation ,,2,, + V(x), = |,|p , 1, on a manifold or in Euclidean space. Here V represents the potential, p an exponent greater than 1, and , a small parameter corresponding to the Planck constant. As , tends to 0 (in the semiclassical limit) we exhibit complex-valued solutions that concentrate along closed curves and whose phases are highly oscillatory. Physically these solutions carry quantum-mechanical momentum along the limit curves. © 2008 Wiley Periodicals, Inc. [source] Adaptive control using multiple models, switching and tuningINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 2 2003Kumpati S. Narendra Abstract The past decade has witnessed a great deal of interest in both the theory and practice of adaptive control using multiple models, switching, and tuning. The general approach was introduced in the early 1990s to cope with large and rapidly varying parameters in control systems. During the following years, detailed mathematical analyses of special classes of systems were carried out. Considerable empirical evidence was also collected to demonstrate the practical viability of the methods proposed. This paper attempts to review critically the stability questions that arise in the study of such systems, describes recent extensions of the approach to non-linear adaptive control, and discuss briefly promising new areas of research, particularly related to the location of models. Copyright © 2003 John Wiley & Sons, Ltd. [source] Guaranteed H, robustness bounds for Wiener filtering and predictionINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 1 2002P. Bolzern Abstract The paper deals with special classes of H, estimation problems, where the signal to be estimated coincides with the uncorrupted measured output. Explicit bounds on the difference between nominal and actual H, performance are obtained by means of elementary algebraic manipulations. These bounds are new in continuous-time filtering and discrete-time one-step ahead prediction. As for discrete-time filtering, the paper provides new proofs that are alternative to existing derivations based on the Krein spaces formalism. In particular, some remarkable H, robustness properties of Kalman filters and predictors are highlighted. The usefulness of these results for improving the estimator design under a mixed H2/H, viewpoint is also discussed. The dualization of the analysis allows one to evaluate guaranteed H, robustness bounds for state-feedback regulators of systems affected by actuator disturbances. Copyright © 2001 John Wiley & Sons, Ltd. [source] A follow-up study of graduates from special classes for school refusers in junior high schoolsPSYCHIATRY AND CLINICAL NEUROSCIENCES, Issue 1 2004AKIRA TAKEI MD No abstract is available for this article. [source] | ||||||||||||||||||||||