bluuebunny/crossref_metadata_2025 huggingface dataset:
Lamina Emergent Mechanisms and Their Basic Elements
Authors: Jacobsen Joseph O. , Winder Brian G. , Howell Larry L. , Magleby Spencer P.
Published: January 2010

Lamina emergent mechanisms (LEMs) are fabricated from planar materials (lamina) and have motion that emerges out of the fabrication plane. LEMs provide an opportunity to create compact, cost-effective devices that are capable of accomplishing sophisticated mechanical tasks. They offer the advantages of planar fabrication, a flat initial state (compactness), and monolithic composition (which provides the advantages associated with compliant mechanisms). These advantages come with the tradeoff of challenging design issues. LEM challenges include large, nonlinear deflections, singularities due to two possible motion configurations as they leave their planar state, and coupling of material properties and geometry in predicting mechanism behavior. This paper defines lamina emergent mechanisms, motivates their study, and proposes a fundamental framework on which to base future LEM design. This includes the fundamental components (created by influencing geometry, material properties, and boundary conditions) and basic mechanisms (including planar four-bars and six-bars, and spherical and spatial mechanisms).
Invariant Description of Rigid Body Motion Trajectories
Authors: De Schutter Joris
Published: January 2010

This paper presents a minimal invariant coordinate-free description of rigid body motion trajectories. Based on a motion model for the instantaneous screw axis, a time-based coordinate-free description consisting of six scalar functions of time is defined. Analytical formulas are presented to obtain these functions from the pose or twist coordinates of a motion trajectory. The time-based functions are then stripped from their temporal information yielding five independent geometric functions together with a scalar motion profile. The geometric functions are shown to be invariant with respect to time scale, linear and angular scale, motion profile, reference frame, and reference point on the rigid body used to express the translational components of the motion. An algorithm is given to reconstruct a coordinate representation of a motion trajectory from its coordinate-free description. A numerical example illustrates the validity of the approach.
Generation of Under-Actuated Manipulators With Nonholonomic Joints From Ordinary Manipulators
Authors: Grosch Patrick , Di Gregorio Raffaele , Thomas Federico
Published: January 2010

This paper shows how to generate underactuated manipulators by substituting nonholonomic spherical pairs for (holonomic) spherical pairs in ordinary (i.e. not underactuated) manipulators. As a case study, an underactuated manipulator, previously proposed by one of the authors, is demonstrated to be generated, through this pair substitution from an inversion of the 6-3 fully parallel manipulator. Moreover, the kinetostatic analysis of this underactuated manipulator is reconsidered, and a simple and compact formulation is obtained. The results of this kinetostatic analysis can be used both in the design of the underactuated manipulator and in its control.
A Tristable Mechanism Configuration Employing Orthogonal Compliant Mechanisms
Authors: Chen Guimin , Aten Quentin T. , Zirbel Shannon , Jensen Brian D. , Howell Larry L.
Published: January 2010

Tristable mechanisms, or devices with three distinct stable equilibrium positions, have promise for future applications, but the complexities of the tristable behavior have made it difficult to identify configurations that can achieve tristable behavior while meeting practical stress and fabrication constraints. This paper describes a new tristable configuration that employs orthogonally oriented compliant mechanisms that result in tristable mechanics that are readily visualized. The functional principles are described and design models are derived. Feasibility is conclusively demonstrated by the successful operation of four embodiments covering a range of size regimes, materials, and fabrication processes. Tested devices include an in-plane tristable macroscale mechanism, a tristable lamina emergent mechanism, a tristable micromechanism made using a carbon nanotube-based fabrication process, and a polycrystalline silicon micromechanism.
Structural Analysis of Wind-Turbine Blades by a Generalized Timoshenko Beam Model
Authors: Otero Alejandro D. , Ponta Fernando L.
Published: January 2010

An important aspect in wind-turbine technology nowadays is to reduce the uncertainties related to blade dynamics by the improvement of the quality of numerical simulations of the fluid-structure interaction process. A fundamental step in that direction is the implementation of structural models capable of capturing the complex features of innovative prototype blades, so that they can be tested at realistic full-scale conditions with a reasonable computational cost. To this end, we developed a code based on a modified implementation of the variational-asymptotic beam sectional (VABS) technique proposed by Hodges et al. VABS has the capacity of reducing the geometrical complexity of the blade section into a stiffness matrix for an equivalent beam, allowing accurate modeling of the 3D structure of the blade as a 1D finite-element problem. In this paper, we report some recent results we have obtained by applying our code to full-scale composite laminate wind-turbine blades, analyzing the fundamental vibrational modes and the stress load in normal operational conditions.
Wind Speed Estimation Algorithm in the Presence of Observation Noise
Authors: Mok Ken
Published: January 2010

A stochastic hub-height wind speed estimation algorithm for wind turbines, which requires only the rotor angular velocity measurement in the presence of observation noise is proposed. It is assumed that the power curve and the total inertia of the rotor are known a priori. We use the maximum likelihood estimator to identify the hub-height wind speed, which is formulated as one of the state variables in the nonlinear model. The theory and algorithm are verified by both simulated and experimental data in the presence of measurement noise. The effects of the initial guess, the noise variance, and the time history are discussed.
Analysis and metrology with a focused helium ion beam
Authors: Sijbrandij Sybren , Notte John , Scipioni Larry , Huynh Chuong , Sanford Colin
Published: January 2010

The newly introduced ORION™ helium ion microscope has been used for high resolution imaging and nanofabrication. More recently, an energy sensitive detector has been developed that permits the measurement of the energy spectrum of the backscattered helium ions. The spectra can be analyzed directly or compared with the simulated spectra from hypothetical models of the specimen. The technique can provide information about the elemental composition of the specimen or structural information (for example, layer thickness) of the specimen.
Direct thermal-UV nanoimprint of an iron-containing organometallic hybrid film
Authors: Han Huilan , Bhushan Abhinav , Yaghmaie Frank , Davis Cristina E.
Published: January 2010

Direct thermal-UV nanoimprinting of an organometallic hybrid film has been demonstrated to fabricate nanoscale features into a novel organic-inorganic solution containing selected metals. The film can be patterned at low temperature and pressure, and requires only a short processing time. When analyzed by energy dispersion X-ray spectroscopy, the authors observe both organic and metal content in the final patterned features. They have also observed that film thermal stability increases after UV and oxygen plasma treatments, which may lead to devices that perform well across a wide spectrum of temperatures.
Spin-coatable HfO2 resist for optical and electron beam lithographies
Authors: Saifullah M. S. M. , Khan M. Z. R. , Hasko David G. , Leong Eunice S. P. , Neo Xue L. , Goh Eunice T. L. , Anderson David , Jones Geraint A. C. , Welland Mark E.
Published: January 2010

Conventional patterning of HfO2 as a gate dielectric is a multistep complicated process that involves deposition of oxide, photolithography, and hard mask etching. In order to simplify the process of HfO2 patterning, the authors have developed photo- and electron beam-sensitive spin-coatable HfO2 resists for direct writing. They were prepared by reacting hafnium tert-butoxide with benzoylacetone in n-butanol and were found to be highly stable in air. Fourier transform infrared studies suggest that exposure to radiation results in the gradual removal of organic material from the resist and the enrichment of the resist with inorganics. This makes the exposed resist insoluble in organic solvents such as ethanol, thereby providing high-resolution negative patterns as small as ∼10nm wide. A silicon-on-insulator field effect transistor has been fabricated using sol-gel-derived HfO2 resist as a high-k gate dielectric and characterized over a range of temperatures. At room temperature a relatively high gate leakage current was observed which degrades the device performance, but at low temperatures this leakage current is strongly suppressed.
Health effects of passive smoking .5. Parental smoking and allergic sensitisation in children.
Authors: Strachan D P , Cook D G
Published: January 2010

BACKGROUND: A systematic review was conducted of the effects of parental smoking on immunoglobulin (IgE) levels, skin prick positivity, and allergic rhinitis or eczema in children. Asthma was excluded in order to distinguish more clearly the effect of passive smoke exposure on allergic sensitisation. METHODS: Thirty six relevant publications were identified after consideration of 692 articles selected by electronic search of the Embase and Medline databases using keywords relevant to passive smoking in children. The search was completed in April 1997 and identified nine studies of IgE in neonates, eight of IgE in older children, 12 which included skin prick tests, and 10 describing symptoms of allergic disease other than asthma or wheezing. A quantitative meta-analysis was possible only for the studies reporting skin prick tests. RESULTS: Several large studies failed to confirm early reports of a substantial or statistically significant association of maternal smoking with concentrations of total serum IgE in neonates or in older children. No consistent association emerged between parental smoking and allergic rhinitis or eczema. Few of these studies adjusted for potential confounding variables. The quantity and quality of evidence was greatest for skin prick tests, and studies of parental smoking during pregnancy or infancy were broadly consistent in showing no adverse effect on prick positivity (pooled odds ratio 0.87, 95% confidence interval 0.62 to 1.24). There was much greater and statistically significant (p = 0.002) heterogeneity of odds ratios relating current parental smoking to skin prick positivity. CONCLUSIONS: Parental smoking, either before or immediately after birth, is unlikely to increase the risk of allergic sensitisation in children.
Can reactive airways dysfunction syndrome (RADS) transform into occupational asthma due to "sensitisation" to isocyanates?
Authors: Leroyer C , Perfetti L , Cartier A , Malo J L
Published: January 2010

The case history is described of a worker who presented with a history suggestive of reactive airways dysfunction syndrome which occurred after an acute high level inhalation of diphenylmethane diisocyanate. Further exposure at work, at a time when concentrations of isocyanates were no longer "irritant", suggested occupational asthma; this diagnosis was confirmed by a specific inhalation challenge test.
Effect of repeated sputum induction on cell counts in normal volunteers.
Authors: Nightingale J A , Rogers D F , Barnes P J
Published: January 2010

BACKGROUND: Sputum induction is becoming more commonly used to assess airway inflammation. Since it is a relatively non-invasive procedure it may be useful for repeated measurements over a short period of time. METHODS: To assess the repeatability of the method over a 24 hour period, eight healthy, non-smoking, non-atopic subjects (four men) of mean age 30 years underwent sputum induction, repeated at eight hours and 24 hours. Sputum was induced by inhalation of 3.5% saline. Absolute and differential counts of inflammatory cells were performed on the whole sputum after dilution in Hank's balanced salt solution containing 1% dithiothreitol to solubilise the mucus content of the samples. RESULTS: There was a significant rise in the percentage of neutrophils in the eight hour sample compared with the baseline (57%, range 25-94% at eight hours compared with 28%, range 19-60%: median difference 26%). The median baseline percentage of macrophages was 55% (range 26-69%) which fell to 38% (range 3-56%: median difference 22%) at eight hours and 19% (range 14-59%: median difference 25%) at 24 hours. There was no significant change in the differential counts of eosinophils, lymphocytes or columnar epithelial cells, nor in any of the absolute cell counts, at any time point. CONCLUSIONS: Sputum induction may have limited utility in serial assessment of neutrophilic airway inflammation in normal subjects within a 24 hour period.
Correlation between exhaled nitric oxide, sputum eosinophils, and methacholine responsiveness in patients with mild asthma.
Authors: Jatakanon A , Lim S , Kharitonov S A , Chung K F , Barnes P J
Published: January 2010

BACKGROUND: Eosinophils in induced sputum and exhaled nitric oxide (NO) are currently used as non-invasive markers in the assessment of airway inflammation in asthma. As both sputum eosinophils (%) and exhaled NO are raised in asthmatic subjects not receiving inhaled steroids and decreased following corticosteroid therapy, a relationship between them is plausible. METHODS: Exhaled NO was measured by chemiluminescence analyser, sputum induction by 3.5% saline inhalation, and bronchial responsiveness was measured as PC20FEV1 methacholine in 35 stable asthmatic patients using beta 2 agonist alone and the correlation between these non-invasive markers of airway inflammation was studied. RESULTS: There were significant correlations between exhaled NO and PC20 (r = -0.64), exhaled NO and sputum eosinophils (%) (r = 0.48), and also between sputum eosinophils (%) and PC20 (r = -0.40). CONCLUSION: The correlation between exhaled NO and PC20 suggests that exhaled NO or the mechanisms leading to its increase may contribute to airway hyperresponsiveness in asthma. Furthermore, the relationship between sputum eosinophils (%), exhaled NO, and PC20 highlight the potential use of eosinophils (%) in induced sputum and exhaled NO to monitor the severity of asthma.
Measurement of sniff nasal and diaphragm twitch mouth pressure in patients.
Authors: Hughes P D , Polkey M I , Kyroussis D , Hamnegard C H , Moxham J , Green M
Published: January 2010

BACKGROUND: Inspiratory muscle weakness is a recognised cause of unexplained dyspnoea. It may be suggested by the finding of a low static inspiratory mouth pressure (MIP), but MIP is a difficult test to perform, with a wide normal range; a low MIP may also occur if the patient has not properly performed the manoeuvre. Further investigation conventionally requires balloon catheters to obtain oesophageal (Poes) and transdiaphragmatic pressure (Pdi) during sniffs or phrenic nerve stimulation. Two non-invasive tests of inspiratory muscle strength have recently been described--nasal pressure during a maximal sniff (Sn Pnas) and mouth pressure during magnetic stimulation of the phrenic nerves (Tw Pmo). The use of these two tests in combination might identify patients without inspiratory muscle weakness who are unable to produce a satisfactory MIP< therefore avoiding the need for investigation with balloon catheters. METHODS: Thirty consecutive patients with clinically suspected inspiratory muscle weakness and a low MIP underwent both conventional (Sn Poes and Tw Pdi) and non-invasive testing (Sn Pnas and Tw Pmo). Weakness was considered to be excluded by a Sn Poes of > or = 80 cm H20 or a Tw Pdi of > or = 20 cm H20. The limit values used to test the hypothesis were Sn Pnas > or = 70 cm H20 or Tw Pmo > or = 12 cm H20. RESULTS: Inspiratory muscle weakness was excluded in 17 of the 30 patients. Fifteen of these would have been identified using Sn Pnas and Tw Pmo, with better results when the two tests were combined. The cut off values selected for Sn Pnas and Tw Pmo were shown by ROC plots to indicate normal strength conservatively, avoiding failure to detect mild degrees of weakness. No patient with global weakness was considered normal by Sn Pnas or Tw Pmo. CONCLUSIONS: In most patients with normal inspiratory strength and a low MIP, Tw Pmo and Sn Pnas used in combination can reliably exclude global inspiratory muscle weakness, reducing the number of patients who need testing with balloon catheters.
Theoretical electronic investigation of the low-lying electronic states of the LuF molecule
Authors: Hamade Y. , Taher F. , Choueib M. , Monteil Y.
Published: January 2010

The theoretical electronic structure of the LuF molecule is investigated, using the Complete Active-Space Self-Consistent Field CASSCF and the MultiReference Configuration Interaction MRCI methods. These methods are performed for 26 electronic states in the representation 2s+1Λ(+/−), neglecting spin–orbit effects. Spectroscopic constants including the harmonic vibrational wave number ωe (cm–1), the relative electronic energy Te (cm–1) referred to the ground state and the equilibrium internuclear distance Re (Å) are predicted for all the singlet and triplet electronic states situated below 50 000 cm–1. Calculated potential energy curves are also reported.
Measurement of strong coupling constant from transverse momentum
Authors: Sepehri Alireza , Ghaffary Tooraj , Zomorrodian Mohammad Ebrahim
Published: January 2010

Data from e+e– annihilation into hadrons at the center of mass energy of 60 GeV are used to study the distribution of momentum components with respect to the jet axis. At high energies, the gluon emission that leads to three jet structures represents a gross violation of the parton model without gluons and finds a most natural interpretation if gluon bremsstrahlung is included. The coupling constant, αs, is measured by two different methods, first by employing the jet clustering algorithm introduced by the JADE group. Using this method, the strong coupling constant is found to be 0.123 ± 0.004. Next, from the event shape distributions, we extract the strong coupling constant, αs, and test its evaluation with energy scale. The results are consistent with the running of αs, expected from QCD predictions. Averaging over different observables, the value of αs is determined to be 0.121 ± 0.007.
PRICING OF CONTINGENT CLAIMS IN A TWO-DIMENSIONAL MODEL WITH RANDOM DIVIDENDS
Authors: GAPEEV PAVEL V. , JEANBLANC MONIQUE
Published: January 2010

We study a model of a financial market in which two risky assets are paying dividends with rates changing their initial values to other constant ones when certain events occur. Such events are associated with the first times at which the value processes of issuing firms, modeled by geometric Brownian motions, fall to some prescribed levels. The asset price dynamics are described by exponential diffusion processes with random drift rates and independent driving Brownian motions. We derive closed form expressions for rational values of European contingent claims, under full and partial information.
THE MIRAGE OF TRIANGULAR ARBITRAGE IN THE SPOT FOREIGN EXCHANGE MARKET
Authors: FENN DANIEL J. , HOWISON SAM D. , MCDONALD MARK , WILLIAMS STACY , JOHNSON NEIL F.
Published: January 2010

We investigate triangular arbitrage within the spot foreign exchange market using high-frequency executable prices. We show that triangular arbitrage opportunities do exist, but that most have short durations and small magnitudes. We find intra-day variations in the number and length of arbitrage opportunities, with larger numbers of opportunities with shorter mean durations occurring during more liquid hours. We demonstrate further that the number of arbitrage opportunities has decreased in recent years, implying a corresponding increase in pricing efficiency. Using trading simulations, we show that a trader would need to beat other market participants to an unfeasibly large proportion of arbitrage prices to profit from triangular arbitrage over a prolonged period of time. Our results suggest that the foreign exchange market is internally self-consistent and provide a limited verification of market efficiency.
PRICES AND SENSITIVITIES OF BARRIER AND FIRST-TOUCH DIGITAL OPTIONS IN LÉVY-DRIVEN MODELS
Authors: BOYARCHENKO MITYA , LEVENDORSKIĬ SERGEI
Published: January 2010

We present a fast and accurate FFT-based method of computing the prices and sensitivities of barrier options and first-touch digital options on stocks whose log-price follows a Lévy process. The numerical results obtained via our approach are demonstrated to be in good agreement with the results obtained using other (sometimes fundamentally different) approaches that exist in the literature. However, our method is computationally much faster (often, dozens of times faster). Moreover, our technique has the advantage that its application does not entail a detailed analysis of the underlying Lévy process: one only needs an explicit analytic formula for the characteristic exponent of the process. Thus our algorithm is very easy to implement in practice. Finally, our method yields accurate results for a wide range of values of the spot price, including those that are very close to the barrier, regardless of whether the maturity period of the option is long or short.
CREDIT RISK MODELING USING TIME-CHANGED BROWNIAN MOTION
Authors: HURD T. R.
Published: January 2010

Motivated by the interplay between structural and reduced form credit models, we propose to model the firm value process as a time-changed Brownian motion that may include jumps and stochastic volatility effects, and to study the first passage problem for such processes. We are lead to consider modifying the standard first passage problem for stochastic processes to capitalize on this time change structure and find that the distribution functions of such "first passage times of the second kind" are efficiently computable in a wide range of useful examples. Thus this new notion of first passage can be used to define the time of default in generalized structural credit models. Formulas for defaultable bonds and credit default swaps are given that are both efficiently computable and lead to realistic spread curves. Finally, we show that by treating joint firm value processes as dependent time changes of independent Brownian motions, one can obtain multifirm credit models with rich and plausible dynamics and enjoying the possibility of efficient valuation of portfolio credit derivatives.
THE CORE COINCIDES WITH THE NUCLEOLUS ALLOCATIONS IN A PUBLIC GOODS ECONOMY WITH TAXATION
Authors: HIRAI TOSHIYUKI
Published: January 2010

We study a public goods economy with a certain tax system to finance public goods provision. Each coalition is allowed to tax the complementary coalition when proposing a new allocation. Taxation is regulated by a public authority so as to satisfy certain restriction on the resulting allocation. We show that the core coincides with the set of nucleolus allocations defined in this economy. We also show that the core is nonempty under the usual convexity assumptions.
EMPLOYMENT BY LOTTO REVISITED
Authors: KLAUS BETTINA , KLIJN FLIP
Published: January 2010

We study employment by lotto (Aldershof et al., 1999), a procedurally fair matching algorithm for the so-called stable marriage problem. We complement Aldershof et al.'s (1999) analysis in two ways. First, we give an alternative and intuitive description of employment by lotto in terms of a probabilistic serial dictatorship on the set of stable matchings. Second, we show that Aldershof et al.'s (1999) conjectures are correct for small matching markets but not necessarily correct for large matching markets.
TRUST AND CULTURE
Authors: JANUS THORSTEN
Published: January 2010

Large populations can gain from economies of scale but lose internal trust due to diluted information. This creates an optimal group size. However, trusting strangers who claim to be members invites outsiders to disguise as insiders and abuse extended trust. Thus, if cultural diversity can raise the imitation cost it can promote cooperation. Even so, however, scale economies are lost when the population subdivides and the cultural boundaries may have to be enforced to prevent assimilation. The model is consistent with norms against inter-cultural marriage and episodic boundary-reinforcing conflict where formal institutions for contract enforcement are weak.
A TWO-STEP SHAPLEY VALUE FOR COOPERATIVE GAMES WITH COALITION STRUCTURES
Authors: KAMIJO YOSHIO
Published: January 2010

In this paper, we study cooperative games with coalition structures. We show that a solution concept that applies the Shapley value to games among and within coalitions and in which the pure surplus that the coalition obtains is allocated among the intra-coalition members in an egalitarian way, is axiomatized by modified axioms on null players and symmetric players and the usual three axioms: efficiency, additivity and coalitional symmetry. In addition to the original definition, we give two expressions of this solution concept. One is an average of modified marginal contributions and the other is the weighted Shapley value of a game with restricted communication.
A COOPERATIVE APPROACH TO QUEUE ALLOCATION OF INDIVISIBLE OBJECTS
Authors: HAMERS HERBERT , KLIJN FLIP , SLIKKER MARCO , VAN VELZEN BAS
Published: January 2010

We consider the allocation of a finite number of indivisible objects to the same number of agents according to an exogenously given queue. We assume that the agents collaborate in order to achieve an efficient outcome for society. We allow for side-payments and provide a method for obtaining stable outcomes.
A NOTE ON THE MONOTONIC CORE
Authors: GETÁN JESÚS , MONTES JESÚS , RAFELS CARLES
Published: January 2010

The monotonic core of a cooperative game with transferable utility is the set formed by all its Population Monotonic Allocation Schemes. In this paper we show that this set always coincides with the core of a certain game, with and without restricted cooperation, associated to the initial game.
A VALUE FOR CEPHOIDAL NTU-GAMES
Authors: ROSENMÜLLER JOACHIM
Published: January 2010

A Cephoid is an algebraic ("Minkowski") sum of finitely many prisms in ℝn. A cephoidal game is an NTU game the feasible sets of which are cephoids. We provide a version of the Shapley NTU value for such games based on the bargaining solution of Maschler–Perles. The value is characterized by a suitable set of axioms
ADVERTISING DECISIONS IN A VERTICAL DISTRIBUTION CHANNEL
Authors: VISCOLANI BRUNO
Published: January 2010

A manufacturer and a retailer are the members of a simple distribution channel for a particular product in a segmented market. The advertising efforts of the two agents have a joint effect on the goodwill of the different market segments and then on the demand. The channel members aim at maximizing their profits, by choosing suitable advertising media and efforts. We focus mainly on competition between manufacturer and retailer, obtaining Nash equilibrium strategies, in the contexts of linear and concave demand. We consider also the possibility of cooperation, obtaining the coordinated channel optimal decisions.
SEQUENTIAL CHOICE AND NON-BAYESIAN OBSERVATIONAL LEARNING
Authors: WISEMAN THOMAS
Published: January 2010

Standard models of observational learning in settings of sequential choice have two key features. The first is that players make decisions by using Bayes' rule to update their beliefs about payoffs from a common prior. The second is that each agent's decision rule is common knowledge, so that subsequent players can draw inferences about unobserved private signals from observable actions. In this paper, I relax the first assumption while maintaining the second. In particular, I look at observational learning by players who choose between two actions using nonparametric methods for estimating payoffs. When players are identical and make inferences using the maximum score method, an informational cascade and herd must result. If players of different payoff types use kernel or nearest-neighbor methods, there are cases in which a cascade need not arise. If one does occur, it must be one in which all players, regardless of type, choose the same action. In some situations, these alternative learning rules perform better than Bayesian updating.
TRASH IT OR SELL IT? A STRATEGIC ANALYSIS OF THE MARKET INTRODUCTION OF PRODUCT INNOVATIONS
Authors: DAWID HERBERT , KOPEL MICHAEL , DANGL THOMAS
Published: January 2010

In this paper a quantity-setting duopoly is considered where one firm develops a new product which is horizontally differentiated from the existing product. The main question examined is which strategically important effects occur if the decision to develop the innovation and the decision to introduce the new product in the market are separated. In our multi-stage game the firm's launch decision is explicitly taken into account. We find an equilibrium where the competitor of the potential innovator strategically over-invests in process innovation in order to push the potential innovator to introduce the new product since this reduces competition for the existing product. It is shown that this effect has positive welfare implications in comparison with the case where the innovator commits ex ante to launching the new product.
A GENERIC APPROACH TO COALITION FORMATION
Authors: APT KRZYSZTOF R. , WITZEL ANDREAS
Published: January 2010

We propose an abstract approach to coalition formation that focuses on simple merge and split rules transforming partitions of a group of players. We identify conditions under which every iteration of these rules yields a unique partition. The main conceptual tool is a specific notion of a stable partition. The results are parametrized by a preference relation between partitions of a group of players and naturally apply to coalitional TU-games, hedonic games and exchange economy games.
THE CLASS OF EFFICIENT LINEAR SYMMETRIC VALUES FOR GAMES IN PARTITION FUNCTION FORM
Authors: HERNÁNDEZ-LAMONEDA L. , SÁNCHEZ-PÉREZ J. , SÁNCHEZ-SÁNCHEZ F.
Published: January 2010

In this paper we study linear symmetric solutions for the space of games in partition function form with n players. In particular, we provide an expression for all linear, symmetric and efficient solutions. Furthermore, adding an additional axiom, we identify a unique value satisfying these properties.
A NECESSARY AND SUFFICIENT CONDITION FOR THE NON-EMPTINESS OF THE SOCIALLY STABLE CORE IN STRUCTURED TU-GAMES
Authors: CESCO JUAN CARLOS
Published: January 2010

In this note we provide a neccesary and sufficient condition for the non-emptiness of the socially stable core of a general structured TU-game which resembles closely the classical condition of balancedness given by Bondareva (1963) and Shapley (1967) to guarantee the non-emptiness of the classical core. Structured games have been introduced in Herings et al. (2007a) and more recently, in Herings et al. (2007b), studied in the framework of games with transferable utility. In the latter paper, the authors provide suffcient conditions for the non-emptiness of the socially stable core, but up to now, no necessary and sufficient condition is known.
DETECTION OF BLOOD VESSELS FROM RETINAL IMAGES USING WATERSHED TRANSFORMATION
Authors: BESSAID A. , FEROUI A. , MESSADI M.
Published: January 2010

Automated analysis and interpretation of retinal images has become an incontournable diagnostic step in ophthalmology. Retinal blood vessels morphology can be an important indicator for diseases such as diabetic retinopathy; and their detection also serves for image registration. This paper presents a method based on mathematical morphology for extraction of vascular tree in color retinal image with low contrast. It consists in contrast enhancement and application of watershed transformation in order to segment blood vessels in digital fundus images.
ARTIFICIAL NEURAL NETWORK BASED ECG ARRHYTHMIA CLASSIFICATION
Authors: HASEENA H. , JOSEPH PAUL K. , MATHEW ABRAHAM T.
Published: January 2010

Reliable and computationally efficient means of classifying electrocardiogram (ECG) signals has been the subject of considerable research effort in recent years. This paper explores the potential applications of a talented, versatile computation model called the Artificial Neural Network (ANN) in the field of ECG signal classification. Two types of ANNs: Multi-Layered Feed Forward Network (MLFFN) and Probabilistic Neural Networks (PNN) are used to classify seven types of ECG beats. It includes six types of arrhythmia data and normal data. Here, parametric modeling strategies are used in conjunction with ANN classifiers to discriminate ECG signals. Instead of giving the ECG data as such, parameters such as fourth order Auto Regressive model coefficients and Spectral Entropy of the signals has been selected. On testing with the Massachusetts Institute of Technology-Beth Israel Hospital (MIT/BIH) arrhythmia database, it has been observed that PNN has better performance than conventionally used MLFFN in ECG arrhythmia classification. MLFFN with Back Propagation Algorithm gives a classification accuracy of 97.54% and PNN gives 98.96%. The classification by PNN also has an advantage that the computation time for classification is lower than that of MLFFN.
DESIGN OF A THRESHOLD FES CONTROL SYSTEM FOR ARM MOVEMENT
Authors: LAN L. , ZHU K. Y. , WEN C. Y.
Published: January 2010

The existing functional electrical stimulation (FES) techniques often required to solve the complex "inverse dynamic problem" to calculate the muscle torques for moving along a desired trajectory. According to the threshold control theory of voluntary motor control, a bio-mimetic threshold control strategy for the FES controller is designed and tested in the human arm movement. The arm is modeled as three segments connected by two hinges joints. The movement is driven by seven muscles and limited in the horizontal plane. All muscles are described by a modified Hill-type muscle model. Simulation results suggest that the threshold FES control system can realize point to point movement and can approximately follow the desired traces in presence of feedback delays up to 20 ms. The movement can also maintain stability under external perturbation or external load. The control system can be employed in clinical application because of the following advantages: (1) The control strategy includes some mature control techniques which had been realized in hardware. (2) Only sophisticated sensors of goniometer and the surface electrodes are needed to provide feedbacks and muscle stimulation. (3) The performance of the control system will not be critically influenced by the slight change of musculo-tendon parameters and feedback delays, and even the parameters of controller are fixed.
AUTOMATIC IDENTIFICATION OF EPILEPTIC EEG SIGNALS USING NONLINEAR PARAMETERS
Authors: ACHARYA U. RAJENDRA , CHUA CHUA KUANG , LIM TEIK-CHENG , DORITHY  , SURI JASJIT S.
Published: January 2010

Epilepsy is a brain disorder causing people to have recurring seizures. Electroencephalogram (EEG) is the electrical activity of the brain signals that can be used to diagnose the epilepsy. The EEG signal is highly nonlinear and nonstationary in nature and may contain indicators of current disease, or warnings about impending diseases. The chaotic measures like correlation dimension (CD), Hurst exponent (H), and approximate entropy (ApEn) can be used to characterize the signal. These features extracted can be used for automatic diagnosis of seizure onsets which would help the patients to take appropriate precautions. These nonlinear features have been reported to be a promising approach to differentiate among normal, pre-ictal (background), and epileptic EEG signals. In this work, these features were used to train both Gaussian mixture model (GMM) and support vector machine (SVM) classifiers. The performance of the two classifiers were evaluated using the receiver operating characteristics (ROC) curves. Our results show that the GMM classifier performed better with average classification efficiency of 95%, sensitivity and specificity of 92.22% and 100%, respectively.
ASSESSMENT OF VOIDING FUNCTION BY ENDOSCOPIC IMAGING — A PRELIMINARY REPORT
Authors: IGARASHI TATSUO , ZENBUTSU SATOKI , NAYA YUKIO , ISHII TAKURO , YU WEN-WEI , YAMANISHI TOMONORI
Published: January 2010

We report a novel method of reconstructing the 3D structure of the prostatic urethra and measuring its elasticity using endoscopic video images, and discuss their relation to clinical relevancy. Information regarding pixel color and brightness in the endoscopic video image is converted to relative distance between the object and the light source. An opened, 3D image of the prostatic urethra is obtained from a video image captured by the endoscope as it is slowly pulled through the urethra. The elasticity of the urethra is determined by recording a video image of the endoscope fixed in the prostatic urethra, with and without irrigation under water pressure of approximately 80 cm H 2 O . Angulation of the prostatic urethra is estimated by the number of intersections between the outline of protruded prostate and the midline of the urethra in patients with severe voiding dysfunction scheduled for transurethral resection of prostate, and in those scheduled for transurethral resection of bladder tumor without apparent discomfort during urination. The number of intersections showed a relationship with voiding symptoms. In conclusion, reconstruction of the 3D structure of the prostatic urethra from endoscopic video images is a feasible method that shows promise for estimating the mechanism of voiding dysfunction.
THE ULTRASONIC THREE-DIMENSIONAL FILTER FOR THE QUANTITATIVE DIAGNOSIS OF LIVER FIBROSIS
Authors: YAMAGUCHI TADASHI , HACHIYA HIROYUKI
Published: January 2010

At present, percutaneous liver biopsy is the gold standard in assessing liver fibrosis such as hepatitis and cirrhosis, but there could be sampling error, and specimens might not represent the state of the whole liver accurately because only about 0.002% of the organ is sampled. In this research, we propose the three-dimensional fiber structure extraction echo filter to realize a quantitative ultrasonic diagnosis. The filter is designed based on a statistical theory, and it is possible to reduce the noise contained in a back scattered ultrasonic echo signal, and to visualize the structure of a fiber.
ADDITIONAL PROPERTIES OF THE NODE-BASED SMOOTHED FINITE ELEMENT METHOD (NS-FEM) FOR SOLID MECHANICS PROBLEMS
Authors: NGUYEN-THOI T. , LIU G. R. , NGUYEN-XUAN H.
Published: January 2010

A node-based smoothed finite element method (NS-FEM) for solving solid mechanics problems using a mesh of general polygonal elements was recently proposed. In the NS-FEM, the system stiffness matrix is computed using the smoothed strains over the smoothing domains associated with nodes of element mesh, and a number of important properties have been found, such as the upper bound property and free from the volumetric locking. The examination was performed only for two-dimensional (2D) problems. In this paper, we (1) extend the NS-FEM to three-dimensional (3D) problems using tetrahedral elements (NS-FEM-T4), (2) reconfirm the upper bound and free from the volumetric locking properties for 3D problems, and (3) explore further other properties of NS-FEM for both 2D and 3D problems. In addition, our examinations will be thorough and performed fully using the error norms in both energy and displacement. The results in this work revealed that NS-FEM possesses two additional interesting properties that quite similar to the equilibrium FEM model such as: (1) super accuracy and super-convergence of stress solutions; (2) similar accuracy of displacement solutions compared to the standard FEM model.
COUPLED ALGORITHMS FOR PIEZOELECTRIC ACTUATOR DESIGN OPTIMIZATION FOR SHAPE CONTROL OF SMART STRUCTURES
Authors: NGUYEN QUAN , TONG LIYONG
Published: January 2010

This paper presents two coupled algorithms for piezoelectric actuator design optimization for shape control of structures with both applied voltages and the shapes of actuators being treated as design variables. The optimum values for the applied voltages to actuators can be determined using the Linear Least Square (LLS) method, whereas the shapes of actuators can be optimized using the Genetic Algorithm (GA). These algorithms are combined together to develop a GA+LLS coupled algorithm, for design optimization of both actuators' shapes and voltages in either an alternating or a concurrent manner. In the alternating approach, LLS is utilized to determine the optimum voltages with given actuator geometry, and then GA is used to determine the optimal actuator shapes with given voltages; the alternating calculations continue until the selected convergence condition is met. In the concurrent approach, the LLS is embedded in GA to determine optimum voltages and then to modify the associated strings for each individual population. Numerical results are presented to validate the proposed algorithms. It is found that the concurrent GALLS algorithm appears to be most efficient and effective.
THE METHOD OF FUNDAMENTAL SOLUTIONS FOR AN INVERSE INTERNAL BOUNDARY VALUE PROBLEM FOR THE BIHARMONIC EQUATION
Authors: LESNIC D. , ZEB A.
Published: January 2010

In this paper, an inverse internal boundary value problem associated to the biharmonic equation is considered. The problem consists of determining unknown boundary conditions from extra interior measurements. The method of fundamental solutions (MFS) is used to discretize the problem and the resulting ill-conditioned system of linear equations is solved using the Tikhonov regularization technique. It is shown that, unlike the least-squares method, the MFS-regularization numerical technique produces stable and accurate numerical solutions for an appropriate choice of the regularization parameter given by the L-curve criterion.
APPROXIMATE SOLUTIONS OF NONLINEAR DIFFERENTIAL DIFFERENCE EQUATIONS
Authors: ABDOU M. A.
Published: January 2010

An extend of He's homotopy perturbation method (HPM) is used for finding a new approximate and exact solutions of nonlinear difference differential equations arising in mathematical physics.

To illustrate the effectiveness and the advantage of the proposed method, two models of nonlinear difference equations of special interest in physics are chosen, namely, Ablowitz–Ladik lattice equations and Relativistic Toda lattice difference equations. Comparisons are made between the results of the proposed method and exact solutions. The results show that the HPM is a attracted method in solving the differential difference equations (DDEs). The proposed method will become a much more interesting method for solving nonlinear DDEs in science and engineering.
SINGULAR INTEGRAL EQUATION METHOD FOR MULTIPLE FLAT PUNCH PROBLEM FOR AN ELASTIC HALF-PLANE
Authors: CHEN Y. Z. , WANG Z. X. , LIN X. Y.
Published: January 2010

When a flat punch is indented on elastic half-plane, the singular stress distribution at the vicinity of the punch corners is studied. The angle distribution for the stress components is also achieved in an explicit form. From obtained singular stress distribution, the punch singular stress factor is defined. The multiple punch problem can be considered as a superposition of many single punch problems. Taking the stress distribution under the punch base as the unknown function and the deformation under punch as the right-hand term, a set of the singular integral equations for the multiple punch problem can be achieved. After the singular integral equations are solved, the stress distributions under punches can be obtained. In addition, the exerting locations of the resultant forces under punches can also be determined. Two numerical examples with the calculated results are presented.
COMPORTEMENT AU VOISINAGE DE 1 DE LA FONCTION DE RÉPARTITION DE φ(n)/n
Authors: TOULMONDE VINCENT
Published: January 2010

Let φ denote Euler's totient function, and G be the distribution function of φ(n)/n. Using functional equations, it is shown that φ(n)/n is statistically close to 1 essentially when prime factors of n are large. A function defined by a difference-differential equation gives a quantitative measure of the statistical influence of the size of prime factors of n on the closeness of φ(n)/n to 1.

As a corollary, an asymptotic expansion at any order of G(1)-G(1-ε) is obtained according to negative powers of log (1/ε), when ε tends to 0+. This improves a result of Erdős (1946) in which he gives the first term of it. By optimally choosing the order of this expansion, an estimation of G(1)-G(1-ε) is deduced, involving an error term of the same size as the best known error term involved in prime number theorem.

Soit φ l'indicatrice d'Euler. Nous étudions le comportement au voisinage de 1 de la fonction G de répartition de φ(n)/n, via la mise en évidence d'équations fonctionnelles. Nous obtenons un résultat mesurant l'influence statistique de la taille du plus petit facteur premier d'un entier générique n quant à la proximité de φ(n)/n par rapport à 1. Ce résultat met en jeu une fonction définie par une équation différentielle aux différences.

Nous en déduisons un développement limité à tout ordre de G(1)-G(1-ε) selon les puissances de 1/(log 1/ε), améliorant ainsi un résultat d'Erdős (1946) dans lequel il obtient le premier terme de ce développement. Une troncature convenable de ce développement fournit un terme d'erreur comparable à celui actuellement connu pour le théorème des nombres premiers.
FOURIER EXPANSIONS WITH MODULAR FORM COEFFICIENTS
Authors: EL-GUINDY AHMAD
Published: January 2010

In this paper, we study the Fourier expansion where the coefficients are given as the evaluation of a sequence of modular forms at a fixed point in the upper half-plane. We show that for prime levels l for which the modular curve X0(l) is hyperelliptic (with hyperelliptic involution of the Atkin–Lehner type) then one can choose a sequence of weight k (any even integer) forms so that the resulting Fourier expansion is itself a meromorphic modular form of weight 2-k. These sequences have many interesting properties, for instance, the sequence of their first nonzero next-to-leading coefficient is equal to the terms in the Fourier expansion of a certain weight 2-k form. The results in the paper generalizes earlier work by Asai, Kaneko, and Ninomiya (for level one), and Ahlgren (for the cases where X0(l) has genus zero).
BOUNDED STEP FUNCTIONS AND FACTORIAL RATIO SEQUENCES
Authors: BELL JASON P. , BOBER JONATHAN W.
Published: January 2010

We study certain step functions whose nonnegativity is related to the integrality of sequences of ratios of factorial products. In particular, we obtain a lower bound for the mean square of such step functions which allows us to give a restriction on when such a factorial ratio sequence can be integral. Additionally, we note that this work has applications to the classification of cyclic quotient singularities.
LOCALIZED BREATHER-LIKE EXCITATIONS IN THE HELICOIDAL PEYRARD–BISHOP MODEL OF DNA
Authors: TABI CONRAD BERTRAND , MOHAMADOU ALIDOU , KOFANE TIMOLEON CREPIN
Published: January 2010

We consider the one-dimensional helicoidal Peyrard–Bishop (PB) model of DNA dynamics. By means of a method based on the Jacobian elliptic functions, we obtain the exact analytical solution which describes the modulational instability and the propagation of a bright solitary wave on a continuous wave background. It is shown that these solutions depend on the modulational (or Benjamin-Feir) instability criterion. Numerical simulations of their propagation show these excitations to be long-lived and suggest that they are physically relevant for DNA.