bluuebunny/crossref_metadata_2025 huggingface dataset:
Mixed reality merchandising: bricks, clicks – and mix
Authors: Koontz Marcy L. , Gibson Ian E.
Published: October 2002

Mixed reality (MR) applications should now be developed for product merchandising. In the light of recent advances in apparel 3‐D design and merchandising technology we argue that MR could now be applied to the sales of relatively low‐end, high volume items, such as clothing and especially sports equipment. The disadvantage that relatively few shoppers could experience the MR application at firsthand, could be offset by the massive leveraging effect of displaying the mixed reality merchandising events within a networked multi‐channel marketing context, which could truly begin to define a shared zone within which on‐line virtual trading can merge with the richly crafted physical environment of a department store. The existence of an MR infrastructure in a store could begin to open the retailing space to on‐line virtual visitor access. Two technical sketches of mixed reality merchandising scenarios (featuring women’s garments and ski equipment) are given as examples.
Differences in purchase behavior between France and the USA: the cosmetic industry
Authors: Weber J. Michael , Capitant de Villebonne Julie
Published: October 2002

This study investigates the differences in purchasing behavior between the US and French cosmetic markets. Our study suggests that a difference should exist due to psychological factors, social influences, and the purchase situation. Our paper will discuss the underlying theoretical perspectives that support our proposition, and illustrate the various components which influence consumer behavior in this particular marketplace. The analysis and investigation is based on the cosmetic industry in terms of comparing US and French consumers and their historical purchase patterns. The results indicate that there are in fact notable differences in purchase behavior. The implications of these findings are important in two primary ways. First, the findings provide support for the theoretical underpinnings. Second, the findings have important managerial implications in terms of developing appropriate product development, distribution and marketing strategies.
Foresight and territorial dynamics
Authors: Godet Michel
Published: October 2002

The development of any region or territory stems from its own dynamic nature. Economic activity and employment are stimulated by the number of local initiatives plus the cross‐fertilisation of those same initiatives. Globalisation, external constraints and technological change are therefore not really obstacles to be overcome but rather opportunities to be seized. In our experience, participatory foresight exercise using simple and appropriate methods has proved to be a powerful lever for promoting territorial dynamics.
Creating a better world: 15 global challenges
Authors: Glenn Jerome C. , Gordon Theodore J.
Published: October 2002

The world is increasingly complex and the most serious challenges are global in nature. Questions to do with sustainable and equitable development, democratic change, terrorism and transnational crime, for instance, require collaborative action among governments, international organizations, corporations, universities, and nongovernmental organizations. This article, which describes 15 global challenges compiled as part of the Millennium Project’s 2002 State of the Future report, assesses the global and local prospects for humanity.
Removing the fear of uncertainty from the future: theory and practice
Authors: Mercer David , Wilter Adele
Published: October 2002

The most important results of our recent work, the culmination of a decade of global research involving several thousand managers and professionals from large organisations, are explored in terms of how long‐range planning may be undertaken more effectively by a wider range of organisations. Thus, it has proved possible to use (simpler) scenario techniques to explore their likely futures and then develop suitable robust strategies to address these – usually with only a minimal impact on the existing optimal corporate strategies. The paper also includes summaries of the wider evidence which validates the fundamental concepts underpinning the concepts involved, but – especially – it illustrates the developments by their use with Surrey County Council.
Future fiction and the military: visions of other worlds?
Authors: Richardson Jacques G.
Published: October 2002

Speculation, hypothesizing and imagination are the dreamer’s tools. Advanced research and novel technology for the military often profit from what are sometimes unstructured approaches to invention. Once that reality materializes, it may be stranger than the phantasma of the most unleashed of minds.
DYNAMICAL CHARACTERISTICS OF DISCRETIZED CHAOTIC PERMUTATIONS
Authors: MASUDA NAOKI , AIHARA KAZUYUKI
Published: October 2002

Chaos theory has been applied to various fields where appropriate random sequences are required. The randomness of chaotic sequences is characteristic of continuous-state systems. Accordingly, the discrepancy between the characteristics of spatially discretized chaotic dynamics and those of original analog dynamics must be bridged to justify applications of digital orbits generated, for example, from digital computers simulating continuous-state chaos. The present paper deals with the chaotic permutations appearing in a chaotic cryptosystem. By analysis of cycle statistics, the convergence of the invariant measure and periodic orbit skeletonization, we show that the orbits in chaotic permutations are ergodic and chaotic enough for applications. In the consequence, the systematic differences in the invariant measures and in the Lyapunov exponents of two infinitesimally L∞-close maps are also investigated.
INVESTIGATIONS OF BIFURCATIONS OF LIMIT CYCLES IN Z2-EQUIVARIANT PLANAR VECTOR FIELDS OF DEGREE 5
Authors: LI JIBIN , CHAN H. S. Y. , CHUNG K. W.
Published: October 2002

Some distributions of limit cycles of Z2-equivariant planar perturbed Hamiltonian polynomial vector fields of degree 5 are investigated. These include examples of specific Z2-equivariant fields and Z4-equivariant fields having up to 23 limit cycles. The configurations of compound eyes are also obtained by using the bifurcation theory of planar dynamical systems and the method of detection functions.
RECONSTRUCTION AND SYNCHRONIZATION OF HYPERCHAOTIC CIRCUITS VIA ONE STATE VARIABLE
Authors: ITOH MAKOTO , CHUA LEON O.
Published: October 2002

In this paper, we demonstrate that some hyperchaotic circuits can be synchronized by using only one state variable. We applied three kinds of synchronization schemes, a continuous synchronization, an impulsive synchronization, and a selective synchronization to these hyperchaotic circuits. Their performance is examined from the viewpoint of synchronization stability and convergence time.
PHASE SYNCHRONIZATION AND CHAOS SUPPRESSION IN A SET OF TWO COUPLED NONLINEAR OSCILLATORS
Authors: GONZALEZ-MIRANDA J. M.
Published: October 2002

A numerical study of the dynamics of two mutually coupled nonlinear oscillators, at least one of them being in a chaotic state, is presented. Each of these oscillators is described as a three-dimensional autonomous flux. The phase of the oscillations, the Lyapunov spectrum and the bifurcation diagram are studied as functions of the coupling strength. When this is increased the two systems entrain, starting to oscillate in phase; then, for further increase, chaos suppression occurs. The study of different cases shows a rich phenomenology which includes multistability, and several bifurcation phenomena. The transitions to chaos suppression and phase synchronization are studied and interpreted in Fourier space on the base of a simple mechanism of mutual induction of motions by means of the coupling.
ON THE BEHAVIOR OF A SELF-EXCITING FARADAY DISK HOMOPOLAR DYNAMO WITH A VARIABLE NONLINEAR SERIES MOTOR
Authors: MOROZ IRENE M.
Published: October 2002

In this paper we seek to bridge the gap between the study of a self-exciting Faraday disk homopolar dynamo with a linear series motor [Hide et al., 1996] and the case when the torque acting on the armature of the motor is proportional to the square of the current flowing through the dynamo [Hide, 1998]. We also focus on the issue of when the nonlinear quenching of oscillatory solutions can occur. The present study is a special case of the more general problem when azimuthal eddy currents are permitted to flow [Moroz & Hide, 2000] and shares with that problem the existence of multiple steady states and Hopf bifurcations. This results in distinct double-zero bifurcations for the trivial and the nontrivial equilibrium states as well as other codimension-two bifurcations, which leads to the suppression of oscillatory solutions.
CLASSICAL ODE AND PDE WHICH OBEY QUANTUM DYNAMICS
Authors: WERBOS PAUL J.
Published: October 2002

It is well known that classical systems governed by ODE or PDE can have extremely complex emergent properties. Many researchers have asked: is it possible that the statistical correlations which emerge over time in classical systems would allow effects as complex as those generated by quantum field theory (QFT)? For example, could parallel computation based on classical statistical correlations in systems based on continuous variables, distributed over space, possibly be as powerful as quantum computing based on entanglement? This paper proves that the answer to this question is essentially "yes," with certain caveats.

More precisely, the paper shows that the statistics of many classical ODE and PDE systems obey dynamics remarkably similar to the Heisenberg dynamics of the corresponding quantum field theory (QFT). It supports Einstein's conjecture that much of quantum mechanics may be derived as a statistical formalism describing the dynamics of classical systems.

Predictions of QFT result from combining quantum dynamics with quantum measurement rules. Bell's Theorem experiments which rule out "classical field theory" may therefore be interpreted as ruling out classical assumptions about measurement which were not part of the PDE. If quantum measurement rules can be derived as a consequence of quantum dynamics and gross thermodynamics, they should apply to a PDE model of reality just as much as they apply to a QFT model. This implies: (1) the real advantage of "quantum computing" lies in the exploitation of quantum measurement effects, which may have possibilities well beyond today's early efforts; (2) Lagrangian PDE models assuming the existence of objective reality should be reconsidered as a "theory of everything." This paper will review the underlying mathematics, prove the basic points, and suggest how a PDE-based approach might someday allow a finite, consistent unified field theory far simpler than superstring theory, the only known alternative to date.
UNIQUE NORMAL FORMS FOR NILPOTENT PLANAR VECTOR FIELDS
Authors: CHEN GUOTING , WANG DUO , WANG XIAOFENG
Published: October 2002

Further reduction of normal forms for nilpotent planar vector fields has been considered. Unique normal form for a special case of an unsolved problem for the Takens–Bogdanov singularity is given. Computations in Maple are used to conjecture the main results and some computations in the proof are also done with Maple.
CHEMICALLY INDUCED HYDRODYNAMIC PATTERN FORMATION: SLOWLY ROTATING DISK ELECTRODE UNDER DISSOLVING CONDITIONS AND GENESIS OF SPATIAL BIFURCATION
Authors: BAUNE M. , PLATH P. J.
Published: October 2002

We investigated the system of a dissolving and slowly rotating steel disk electrode in an unstirred, highly concentrated iron(III) chloride solution (3.5 M). Visible convection vortices in the solution beneath the electrode were observed in the range of rotational speed from 0–25 revolutions per minute (rpm). The convection vortices thus observed were correlated with etched patterns on the surface of the electrode. The curvature of these patterns was found to be dependent on the rotational speed. At a certain value of the rotational speed (the transition region), the curvatures changed sign. A spatial bifurcation dependent on the radius was observed.
PERIODIC NUCLEATION SOLUTIONS OF THE REAL GINZBURG–LANDAU EQUATION IN A FINITE BOX
Authors: ARGENTINA M. , DESCALZI O. , TIRAPEGUI E.
Published: October 2002

We study the stationary solutions of the real Ginzburg–Landau equation with periodic boundary conditions in a finite box. We show explicitly how to construct nucleation solutions allowing transitions between stable plane waves.
CHAOS IN HARTLEY'S OSCILLATOR
Authors: PETER KVARDA
Published: October 2002

In this paper a new deterministic chaotic oscillator with elements equivalent to Hartley's oscillator is presented and described. P-SPICE simulation program and practical measurement are used to prove the deterministic chaotic character of the mentioned circuit.
GLOBAL BIFURCATIONS OF BASINS IN A TRIOPOLY GAME
Authors: AGLIARI ANNA , GARDINI LAURA , PUU TONU
Published: October 2002

A Cournot model based on bounded inverse demand function and constant marginal production costs is studied. The case of three producers is considered and the adjustment process reduces to a three-dimensional noninvertible map in the output of competitors. The analysis of the dynamical behavior of the map is performed by the "critical curve method", extended to the critical surfaces in 3D. By this method, we explain the different bifurcations in the basins of attraction and in the attracting sets. In particular, given the economic application, feasible trajectories are focused, starting from the simple situation of two identical producers and extending the results to the generic case.
A GLOBAL SYNCHRONIZATION CRITERION FOR COUPLED CHAOTIC SYSTEMS VIA UNIDIRECTIONAL LINEAR ERROR FEEDBACK APPROACH
Authors: JIANG GUO-PING , TANG WALLACE K. S.
Published: October 2002

Based on Lyapunov stabilization theory, this paper proposes a new generic criterion of global chaos synchronization between two coupled chaotic systems from a unidirectional linear error feedback coupling approach. The criterion is successfully applied to some typical chaotic systems with different types of nonlinearity, such as the classic Chua's circuit, the modified Chua's circuit with a sine function, and the Rössler and Lorenz chaotic systems. The coupling parameters are determined according to the new criterion so as to ensure the coupled systems' global chaos synchronization.
CHAOTIC ATTRACTOR IN A SIMPLE HYBRID SYSTEM
Authors: YANG XIAO-SONG , LI QINGDU
Published: October 2002

This letter reports the finding of a chaotic attractor in a very simple three-dimensional autonomous hybrid system, which is obtained by applying a discontinuous feedback to a stable linear system. This attractor is different from the known chaotic attractors investigated in the literature and is globally attractive.
LOCAL BIFURCATIONS OF THE CHEN SYSTEM
Authors: LÜ JINHU , ZHOU TIANSHOU , CHEN GUANRONG , ZHANG SUOCHUN
Published: October 2002

This paper introduces a new practical method for distinguishing chaotic, periodic and quasi-periodic orbits based on a new criterion, and apply it to investigate the local bifurcations of the Chen system. Conditions for supercritical and subcritical bifurcations are obtained, with their parameter domains specified. The analytic results are also verified by numerical simulation studies.
CHAOS IN A THREE-DIMENSIONAL GENERAL MODEL OF NEURAL NETWORK
Authors: DAS A. , DAS PRITHA , ROY A. B.
Published: October 2002

The dynamics of a network of three neurons with all possible connections is studied here. The equations of control are given by three differential equations with nonlinear, positive and bounded sigmoidal response function of the neurons. The system passes from stable to periodic and then to chaotic regimes and returns to stationary regime with change in parameter values of synaptic weights and decay rates. We have developed programs and used Locbif package to study phase portraits, bifurcation diagrams which confirm the result. Lyapunov Exponents have been calculated to confirm chaos.
ON THREE OSCILLATOR UNIVERSAL PROBES FOR DETERMINING SYNCHRONIZATION IN ARRAYS OF COUPLED OSCILLATORS
Authors: WU CHAI WAH
Published: October 2002

In a recent paper, Fink et al. described how a coupled array of three oscillators can serve as a universal probe of the synchronization properties in general coupled arrays of oscillators. However, the coupling topology in this probe is not optimal in experimental implementations. For instance, every oscillator is coupled to every other oscillator resulting in many coupling terms. Furthermore, the variable coupling weights at several coupling terms need to be set equal to each other. This means that some component values need to be varied over a range and be perfectly matched to each other in the experimental setup. We present simpler universal probes by utilizing the minimal number of coupling terms and by minimizing the constraint of having the coupling weights matched.
GENERATING CHAOS VIA FEEDBACK CONTROL FROM A STABLE TS FUZZY SYSTEM THROUGH A SINUSOIDAL NONLINEARITY
Authors: LI ZHONG , PARK JIN BAE , CHEN GUANRONG , JOO YOUNG HOON , CHOI YOON HO
Published: October 2002

An approach is proposed for making chaotic a given stable Takagi–Sugeno (TS) fuzzy system using state feedback control of arbitrarily small magnitude. The feedback controller chosen among several candidates is a simple sinusoidal function of the system states, which can lead to uniformly bounded state vectors of the controlled system with positive Lyapunov exponents, and satisfy the chaotic mechanisms of stretching and folding, thereby yielding chaotic dynamics. This approach is mathematically proven for rigorous generation of chaos from a stable TS fuzzy system, where the chaos is in the sense of Li and Yorke. A numerical example is included to visualize the theoretical analysis and the controller design.
COMPLEXITY INFORMATION BASED ANALYSIS OF PATHOLOGICAL ECG RHYTHM FOR VENTRICULAR TACHYCARDIA AND VENTRICULAR FIBRILLATION
Authors: ZHANG HONGXUAN , ZHU YISHENG , XU YUHONG
Published: October 2002

Based on surrogate data hypothesis testing method, this paper presents an improved nonlinear algorithm for analyzing deterministic chaotic signals, which can be applied to the analysis of abnormal rhythm electrocardiosignals. Ventricular tachycardia (VT) and ventricular fibrillation (VF) can be treated as nonlinear chaotic signals that are different from stochastic signals. On the basis of qualitative analysis theory in nonlinear dynamics, the authors forwarded a new definition of complexity rate and developed several relative detection methods for quantitative analysis of VT and VF. The results indicated that these qualitative analysis and quantitative analysis of VT and VF are objective and credible.
CNN DYNAMICS REPRESENTS A BROADER CLASS THAN PDEs
Authors: GILLI M. , ROSKA T. , CHUA L. O. , CIVALLERI P. P.
Published: October 2002

The relationship between Cellular Nonlinear Networks (CNNs) and Partial Differential Equations (PDEs) is investigated. The equivalence between discrete-space CNN models and continuous-space PDE models is rigorously defined. The key role of space discretization is explained. The problem of the equivalence is split into two subproblems: approximation and topological equivalence, that can be explicitly studied for any CNN model. It is known that each PDE can be approximated by a space difference scheme, i.e. a CNN model, that presents a similar dynamic behavior. It is shown, through several examples, that there exist CNN models that are not equivalent to any PDEs, either because they do not approximate any PDE models, or because they have a qualitatively different dynamic behavior (i.e. they are not topologically equivalent to the PDE that they approximate). This proves that the spatio-temporal CNN dynamics is broader than that described by PDEs.
HEAT: HIERARCHICAL ENTROPY APPROACH FOR TEXTURE INDEXING IN IMAGE DATABASES
Authors: DISTASI RICCARDO , NAPPI MICHELE , VITULANO SERGIO
Published: October 2002

This paper illustrates a method, called HEAT, for image indexing based on texture information. The texture's partitioning element is first put into 1-D form and then its Hierarchical Entropy-based Representation is obtained. This representation is used to index the texture in the space of features. The same representation is well suited for contour data, and it has invariance and robustness properties that make it attractive for incorporation into larger systems. A comparison with another performing method is carried out, and the experiments show that the two techniques have slightly different strong points, suggesting different fields of application. In the experimental section, a case study involving over 2500 mammographies from different sources is presented and discussed.
A METHODOLOGY FOR MODELING MULTIMEDIA DATABASES
Authors: COSTAGLIOLA G. , FRANCESE R. , MUSTO A. , POLESE G.
Published: October 2002

The modeling of multimedia databases in the context of multimedia information systems is a complex task. The designer has to model the structure and the dynamic behavior of multimedia objects, together with possible user interactions with them. These can include content-based queries, and dynamic presentations, which might both require the construction of special index structures on the stored data. In this paper we present a methodology for the design of multimedia databases. The methodology extends some of the Unified Modeling Language (UML) diagrams with constructs to model the structure of multimedia objects, their dynamic behavior, presentation layout, and user interactions. These constructs allow a designer to model important aspects of database oriented multimedia applications. As a consequence, it is possible to construct refinement techniques to map our high level models onto logical data models of several target multimedia DBMSs. In particular, we describe how to map our conceptual models onto extended relational data models.
A MULTIMEDIA MODEL BASED ON STRUCTURED MEDIA AND SUB-ELEMENTS FOR COMPLEX MULTIMEDIA AUTHORING AND PRESENTATION
Authors: TIEN TRAN_THUONG , ROISIN CECILE
Published: October 2002

Declarative definition of multimedia presentation such as provided by SMIL standard can be considered as the most significant advance in the multimedia integration domain. However, the requirements of a model that could express richer scenarios for presentations are always a challenge. The work presented here proposes an extended model based on the concept of structured media and sub-elements that allows a finer granularity and a more semantic specification of significant events and locations inside media fragments. The new media fragments can be composed in multimedia scenarios through the specification of temporal, spatial and spatio-temporal relations. Moreover, we propose an abstract animation model that can be combined with the intra-media temporal structuration to specify animation effects in a flexible, not redundant and easy to maintain way. The underlying model is the Madeus model that is a flexible model based on the structural, interval, region and relative constraints. This paper describes the sub-element and the abstract animation models and shows how they are implemented in the Madeus multimedia framework. A complete schema of the video authoring tool based on this model is also specified. Thanks to that, the fine-grained authoring of multimedia scenarios with video media can be done in an easy and effective way.
ProActNet: MODELING PROCESSES THROUGH ACTIVITY NETWORKS
Authors: CHOU SHIH-CHIEN
Published: October 2002

This paper proposes a process-centered software engineering environment (PSEE) called ProActNet (modeling processes through activity networks), which provides a process modeling language also called ProActNet. ProActNet pays special attention to handling human factors, including: 1) facilitating process program development, 2) allowing incremental process program development, 3) modeling abnormal conditions such as worker feedback, abnormally quitting activities, and abnormally canceling activities, and 4) modeling incremental product development. In addition to handling human factors, ProActNet also supports process change (evolution), which is essential in a PSEE. Moreover, ProActNet models processes as unordered, concurrent activities. With this, activity sequence, concurrency, and synchronization need not be specified in a process program, which simplifies process program development.
A SYNTHESIS OF EVALUATION CRITERIA FOR SOFTWARE SPECIFICATIONS AND SPECIFICATION TECHNIQUES
Authors: KHWAJA AMIR A. , URBAN JOSEPH E.
Published: October 2002

Several evaluation criteria exist in the literature for both specification and specification techniques. These evaluation criteria identify a list of desired properties in specifications and specification techniques for judging their goodness. This paper presents a detailed analysis of several specification and specification technique evaluation criteria. Detailed analysis of these criteria identified that there is a lack of consistency in the property definition among criteria. The implication of this lack of differentiation between the two concepts is that the criteria for both specification and specification techniques are intermingled. Since the concept of specification is different from specification technique, the criteria used for one might not be applicable for the other. For example, "completeness" and "consistency" are specification criteria. A specification can be complete and consistent regardless of the medium used to represent the specification, the process used in its construction, the degree/extent of tools and automation used, or whether it is formal or informal. However, there is meaning to denote that a technique can be used to produce "consistent" or "complete" specifications. Hence, for proper applicability of these criteria, this paper separates specification criteria from that of the specification technique criteria. This paper also presents a unified criteria terminology and uses a table to list each criterion property from various researchers mapped to the unified terminology. The paper also identifies and presents a mapping from technique criteria to the specification criteria that shows which technique criteria satisfies specification criteria. The applicability of the mapping is then demonstrated by applying the mapping to a specification language and its support environment.
MOUNTAIN PASS TYPE SOLUTIONS FOR QUASILINEAR ELLIPTIC INCLUSIONS
Authors: CLÉMENT PH. , GARCÍA-HUIDOBRO M. , MANÁSEVICH R.
Published: October 2002

We establish the existence of weak solutions to the inclusion problem [Formula: see text] where Ω is a bounded domain in ℝN, [Formula: see text], and ψ ∊ ℝ × ℝ is a maximal monotone odd graph. Under suitable conditions on ψ, g (which reduce to subcritical and superlinear conditions in the case of powers) we obtain the existence of non-trivial solutions which are of mountain pass type in an appropriate not necessarily reflexive Orlicz Sobolev space. The proof is based on a version of the Mountain Pass Theorem for a non-smooth case.
REGULAR REPRESENTATIONS OF VERTEX OPERATOR ALGEBRAS
Authors: LI HAISHENG
Published: October 2002

This paper is to establish a theory of regular representations for vertex operator algebras. In the paper, for a vertex operator algebra V and a V-module W, we construct, out of the dual space W*, a family of canonical weak V ⊗ V-modules [Formula: see text] with a nonzero complex number z as the parameter. We prove that for V-modules W, W1 and W2, a P(z)-intertwining map of type [Formula: see text] in the sense of Huang and Lepowsky exactly amounts to a V ⊗ V-homomorphism from W1 ⊗ W2 into [Formula: see text]. Combining this with Huang and Lepowsky's one-to-one linear correspondence between the space of intertwining operators and the space of P(z)-intertwining maps of the same type we obtain a canonical linear isomorphism fromthe space [Formula: see text] of intertwining operators of the indicated type to [Formula: see text]. Denote by RP(z)(W) the sum of all (ordinary) V ⊗ V-submodules of [Formula: see text]. Assuming that V satisfies certain suitable conditions, we obtain a canonical decomposition of RP(z)(W) into irreducible V ⊗ V-modules. In particular, we obtain a decomposition of Peter–Weyl type for RP(z)(V). Denote by ℱP(z) the functor from the category of V-modules to the category of weak V ⊗ V-modules such that ℱP(z)(W)=RP(z)(W'). We prove that for V-modules W1, W2, a P(z)-tensor product of W1 and W2 in the sense of Huang and Lepowsky exactly amounts to a universal from W1 ⊗ W2 to the functor ℱP(z). This implies that the functor ℱP(z) is essentially a right adjoint of the Huang–Lepowsky's P(z)-tensor product functor. It is also proved that RP(z)(W) for [Formula: see text] are canonically isomorphic V ⊗ V-modules.
VARIATIONAL APPROXIMATION OF FREE-DISCONTINUITY ENERGIES WITH LINEAR GROWTH
Authors: ALICANDRO ROBERTO , FOCARDI MATTEO
Published: October 2002

We provide a variational approximation for quasiconvex energies with linear growth, defined on vector valued generalized functions with bounded variation, in the framework of free-discontinuity problems.
UNIQUENESS THEOREMS FOR HARMONIC MAPS INTO METRIC SPACES
Authors: MESE CHIKAKO
Published: October 2002

Recent developments extend much of the known theory of classical harmonic maps between smooth Riemannian manifolds to the case when the target is a metric space of curvature bounded from above. In particular, the existence and regularity theorems for harmonic maps into these singular spaces have been successfully generalized. Furthermore, the uniqueness of harmonic maps is known when the domain has a boundary (with a smallness of image condition if the target curvature is bounded from above by a positive number). In this paper, we will address the question of uniqueness when the domain space is without a boundary in two cases: one, when the curvature of the target is strictly negative and two, for a map between surfaces with nonpositive target curvature.
ON THE COHOMOLOGY OF $\bar{\mathcal M}_{0,n}({\mathbb P}^1,d)$
Authors: BINI GILBERTO , FONTANARI CLAUDIO
Published: October 2002

Here we investigate rational cohomology of the moduli space of stable maps to the complex projective line with a purely algebro-pgeometric approach. In particular, we prove vanishing theorems for all its odd Betti numbers, and we give an explicit description by generators and relations of its second cohomology group.
A GENERALIZATION OF THE ATIYAH–DUPONT VECTOR FIELDS THEORY
Authors: TANG ZIZHOU , ZHANG WEIPING
Published: October 2002

To generalize the Hopf index theorem and the Atiyah–Dupont vector fields theory, one is interested in the following problem: for a real vector bundle E over a closed manifold M with rank E = dim M, whether there exist two linearly independent cross sections of E? We provide, among others, a complete answer to this problem when both E and M are orientable. It extends the corresponding results for E = TM of Thomas, Atiyah, and Atiyah–Dupont. Moreover we prove a vanishing result of a certain mod 2 index when the bundle E admits a complex structure. This vanishing result implies many known famous results as consequences. Ideas and methods from obstruction theory, K-theory and index theory are used in getting our results.
AN ASYMPTOTICALLY PERIODIC SCHRÖDINGER EQUATION WITH INDEFINITE LINEAR PART
Authors: LI GONGBAO , SZULKIN ANDRZEJ
Published: October 2002

We consider the Schrödinger equation - Δ u + V(x)u = f(x,u), where V is periodic and f asymptotically periodic in the x-variables, 0 is in a spectral gap of - Δ + V and f is either asymptotically linear or superlinear as |u| → ∞. We show that this equation has a solution u ∈ H1(RN), u ≠ 0.
CPAP titration by an auto-CPAP device based on snoring detection: a clinical trial and economic considerations
Authors: Berkani M , Lofaso F , Chouaid C , Pia d'Ortho M , Theret D , Grillier-Lanoir V , Harf A , Housset B
Published: October 2002

This study aimed to assess the ability of an auto-nasal continuous positive airway pressure (nCPAP) device (REM + auto; NPBFD, Nancy, France) to predict the optimal constant nCPAP level. The apnoea/hypopnoea detection facility of the auto-nCPAP device was deliberately disabled and nasal mask pressure vibration detection was the only mode of pressure setting. The auto-nCPAP device was tested on 10 previously untreated patients with obstructive sleep apnoea during a single night, with ambulatory polysomnography performed in a conventional hospital room; the efficacy of the fixed pressure determined by the auto-nCPAP device was assessed by an ambulatory full polysomnography 2 weeks after the initiation of treatment at home. The fixed nCPAP pressure was effective (apnoea/hypopnoea and arousal indices <10 events x h(-1)) in all but two of the 10 patients studied. When the fixed nCPAP pressure was increased by 2 cmH2O in these two patients, sleep and respiration were normalized. Since only 12 ambulatory polysomnographic recordings were used to determine the effective nasal continuous positive airway pressure level, and as the device restored normal breathing and sleep in all 10 patients, it was concluded that this method of nasal continuous positive airway pressure titration may improve cost-effectiveness and reduce waiting lists in sleep laboratories.
Detection of apnoeas, hypopnoeas and arousals by the AutoSet in the sleep apnoea/hypopnoea syndrome
Authors: Rees K , Wraith PK , Berthon-Jones M , Douglas NJ
Published: October 2002

Limited sleep study systems are increasingly being used to diagnose the sleep apnoea/hypopnoea syndrome, but validation is essential and detection of arousal's desirable. One such system (AutoSet) was validated on an event-by-event basis, and the hypothesis that sudden large breaths detected by this system mark arousal from sleep was also examined. Twenty consecutive patients (apnoea/hypopnoea index (AHI) 39+/-6 (SEM)) underwent polysomnography (PSG), which included real-time signals of AutoSet (Version 3.03) scored events. PSG respiratory events were defined using airflow and thoracoabdominal movement and AutoSet events using nasal pressure. All apnoeas were scored by both systems, but 41% more hypopnoeas were scored on PSG and these were clinically significant, with 78% ending in cortical arousal. Twenty per cent of apnoeas and hypopnoeas scored by the AutoSet occurred during wakefulness. Large breaths, defined as a two-thirds increase in ventilation, marked 77% of respiratory-associated but only 9% of spontaneous arousals. Large breaths also marked 48% of "autonomic" arousals following respiratory events without visible electroencephalographic changes. Twenty-seven per cent of large breaths occurred during wakefulness. This study shows that the AutoSet and the standard polysomnographic approach differ in their detection of hypopnoeas. The AutoSet underdetected hypopnoeas during sleep, but also included some hypopnoeas occurring during wakefulness. Detection of large breaths may potentially be useful for identifying respiratory arousals. Detection of periods of wakefulness may improve the accuracy of the system.
Simultaneous laboratory-based comparison of ResMed Autoset with polysomnography in the diagnosis of sleep apnoea/hypopnoea syndrome
Authors: Mayer P , Meurice JC , Philip-Joet F , Cornette A , Rakotonanahary D , Meslier N , Pepin JL , Levy P , Veale D
Published: October 2002

ResMed Autoset (AS) is a simplified diagnosis system for obstructive sleep apnoea/hypopnoea syndrome (OSAS) based on the respiratory flow/time relationship by pressure variation measured through simple nasal prongs. A multicentre prospective trial was used to compare AS and polysomnography (PSG) for diagnosing 95 patients, with suspected OSAS. Physicians gave a pretest probability of the patient having OSAS. The apnoea/hypopnoea index (AHI) was compared between the two methods of diagnosis for the whole population and for subgroups according to the pretest probability. Twenty-four patients had AHI < 15 events x h(-1) on PSG and 19 AHI 15-30, and 52 patients had AHI > or = 30. Correlation between AHI assessed by AS and PSG was r=0.87 for total sleep time (TST), p<0.0001. A Bland and Altman plot gave an agreement between the two methods of +/-40%. For a threshold of AHI > or = 15 events x h(-1) to diagnose OSAS, AS has a sensitivity of 92%, specificity of 79%, positive predictive value of 93% and negative predictive value of 76%. With a pretest probability > or = 80%, sensitivity and positive predictive value were 98 and 100% respectively. Of six false negative, four had a high pretest probability (> 80%) or Epworth score > or = 10. Using these parameters as a criterion for proceeding to PSG after a negative AS study would mean that two apnoeic patients (AHI 20 and 17 events x h(-1) by PSG) would escape detection. The Autoset is useful for the detection of obstructive sleep apnoea but with high pretest probability and a negative Autoset result polysomnography should be performed.
Simplified diagnostic procedure for obstructive sleep apnoea syndrome: lower subsequent compliance with CPAP
Authors: Krieger J , Sforza E , Petiau C , Weiss T
Published: October 2002

The aim of this study was to investigate whether a simplified diagnostic procedure based on ambulatory monitoring with MESAM IV altered subsequent compliance with continuous positive airway pressure (CPAP) in obstructive sleep apnoea (OSA) patients. During a period of 16 months, 60 patients with symptoms evocative of OSA and positive MESAM recording were prescribed CPAP after titration with standard polysomnography. Compliance was followed during 2 yrs based on built-in time counters and was compared with the compliance in two comparison groups: an equal number of equally severely affected patients diagnosed with standard polysomnography during the 18 months (8 months before and 8 months after) preceding and following the study period and a group of 48 patients with an estimated similar apnoea/hypopnoea index but less typical clinical and/or MESAM features, diagnosed as having OSA based on polysomnography during the study period. The three groups were not different by age, body mass index, or sleepiness score. Patients diagnosed with the ambulatory procedure had higher drop-out rates (21.7% versus 10% and 6.25%; p<0.05) and lower rates of use of their CPAP (43+/-0.3 h x night(-1)) than any of the control groups (53+/-0.2 and 5.6+/-0.2 h x night(-1), p<0.05). In conclusion, there is a risk that ambulatory diagnostic procedures alter the relationship of patients to their disease and/or the medical staff so that subsequent compliance with treatment may be decreased. The greatest care concerning compliance should be taken before an ambulatory-based diagnostic procedure is implemented.
Characteristics and survival of patients prescribed long-term oxygen therapy outside prescription guidelines
Authors: Veale D , Chailleux E , Taytard A , Cardinaud JP
Published: October 2002

Criteria for the prescription of long-term oxygen therapy (LTOT) have been published by academic societies and regulatory bodies, but many prescriptions for LTOT do not fulfil these criteria. Demographic, functional data and survival were compared in chronic obstructive pulmonary disease (COPD) patients with different levels of oxygenation, i.e. arterial oxygen tension (Pa,O2) < 8 kPa or > or = 8 kPa (60 mmHg), at the time of initial registration in the ANTADIR Observatory. Data were collected between 1984-1995. Selection criteria were a diagnosis of COPD or emphysema with forced expiratory volume in one second (FEV1) < 80% pred, FEV1/vital capacity (VC) < 70% and age between 18-75 yrs. Of 7,700 patients prescribed LTOT 18.5% had stable Pa,O2 > or = 8 kPa. While the FEV1 was the same they differed from the patients with more severe hypoxaemia in having a higher rate of diagnosis of primary emphysema and a lower arterial carbon dioxide tension (Pa,CO2). In this group of patients LTOT was more frequently administered as liquid oxygen than in other patients on LTOT. The survival of these patients was reduced compared to the general population of the same age and sex but comparable to that of patients with a Pa,O2 between 6.7-8 kPa (50-60 mmHg). Patients prescribed long-term oxygen therapy with an arterial oxygen tension > or = 8 kPa (60 mmHg) in the ANTADIR network were shown to have severe chronic obstructive pulmonary disease on the basis of spirometry and their survival was similar to that of more hypoxaemic patients. Randomized controlled trials of the effect of long-term oxygen therapy in patients with arterial oxygen tension > or = 8 kPa are needed.
Exercise performance and gas exchange after bilateral video-assisted thoracoscopic lung volume reduction for severe emphysema
Authors: Stammberger U , Bloch KE , Thurnheer R , Bingisser R , Weder W , Russi EW
Published: October 2002

Lung volume reduction surgery (LVRS) improves dyspnoea and pulmonary function in selected patients with severe emphysema. The purpose of this study was to assess the effects of LVRS on exercise performance and gas exchange in relation to changes in pulmonary function. In 40 patients (63.2+/-1.4 yrs, mean+/-SE) with severe emphysema (forced expiratory volume in one second (FEV1) 29+/-1% predicted, residual volume/total lung capacity (RV/TLC) ratio: 0.63+/-0.01) we assessed dyspnoea, pulmonary function and exercise performance before and 3 months after bilateral video-assisted thoracoscopic LVRS. The Medical Research Council dyspnoea score fell from 3.5+/-0.1 to 1.4+/-0.1 (p<0.0005); FEV1 increased by 55+/-9% to 44+/-2% pred (p<0.0005), RV/TLC decreased from 0.63+/-0.01 to 0.51+/-0.02 (p<0.0005). The diffusing capacity remained unchanged. Maximal work load during bicycle ergometry increased from 34.3+/-2.0 to 48.9+/-2.4 W (p< 0.0005), maximal oxygen uptake (V'O2max) from 10.0+/-0.4 to 12.8+/-0.3 mL x kg(-1) x min(-1) (p<0.0005). The increase in maximal ventilation during exercise (V'Emax) from 29.5+/-1.5 to 38.6+/-1.8 L x min(-1) (p<0.0005) was associated with increases in tidal volumes at isowatt and maximal exercise while corresponding breathing frequencies remained unaltered. The increases in V'O2max and V'Emax correlated with the increases in FEV1 and the decreases in RV/TLC. We conclude that the improvement in pulmonary hyperinflation and airflow obstruction after bilateral thoracoscopic lung volume reduction surgery may reduce ventilatory limitation, thereby increasing exercise capacity.
Diagnosis of emphysema in patients with chronic bronchitis: a new approach
Authors: Kohlhaufl M , Brand P , Selzer T , Scheuch G , Meyer T , Weber N , Schulz H , Haussinger K , Heyder J
Published: October 2002

Aerosol-derived airway morphometry (ADAM) and aerosol bolus dispersion (D) are altered in patients or animal models with lung emphysema. This study was performed to examine the sensitivity and specificity of ADAM and D in the detection of emphysema in vivo compared with conventional lung function parameters. The study comprised patients with chronic obstructive bronchitis (COB) without emphysema (group COB; n=19, age 56+/-8 yrs, forced expiratory volume in one second (FEV1)/vital capacity (VC) 66+/-12% predicted) and patients with chronic bronchitis with high-resolution computed tomography-confirmed emphysema (group COB-E; n=20), age 65+/-7 yrs, FEV1/VC 44+/-16% pred). Using monodisperse aerosol particles ADAM assessed the calibres of peripheral airspaces, while D measured convective gas mixing. Among all lung function parameters, ADAM and D showed the highest sensitivity and specificity for separating patients with COB from those with COB-E (area under the receiver operating characteristics curve (pROC) 0.99 and 1.0, respectively). In patients with COB aerosol parameters did not differ from those found in the control group, whereas patients with COB-E exhibited a two-fold increase in peripheral airspace dimensions compared with subjects with COB (0.86+/-0.07 versus 0.37+/-0.02 mm, p=0.0001) and an increase in D by >50% (541+/-74 versus 345+/-42 cm3, p=0.0001). In conclusion, aerosol-derived airway morphometry and aerosol bolus dispersion are powerful tools in the differential diagnosis of chronic obstructive pulmonary disease.
Effect of salbutamol on dynamic hyperinflation in chronic obstructive pulmonary disease patients
Authors: Tantucci C , Duguet A , Similowski T , Zelter M , Derenne JP , Milic-Emili J
Published: October 2002

Expiratory flow limitation (EFL), which promotes dynamic hyperinflation and increased work of breathing, often occurs in chronic obstructive pulmonary disease (COPD). The purpose of this study was to assess the effect of bronchodilators on EFL and end-expiratory lung volume in patients with moderate-to-severe COPD. EFL was assessed by applying negative expiratory pressure (NEP) at the mouth during tidal expiration. EFL was present when expiratory flow did not increase or increased only in the early phase of expiration with NEP. In 18 patients (age 65+/-2 yrs; forced expiratory volume in one second (FEV1)=45+/-4% predicted) pulmonary function tests and a series of NEP (-3.5 cmH2O) test breaths were performed at rest in a sitting position before and 20 min after inhalation of 400 microg of salbutamol. EFL was detected in 11 patients and persisted after salbutamol in all of these flow-limited (FL) patients. After bronchodilator administration FL patients exhibited a significant decrease in functional residual capacity (FRC) associated with an increase in inspiratory capacity (IC). In contrast, no changes in FRC and IC were observed in the seven non flow-limited (NFL) patients after administration of salbutamol. Except for one NFL patient, the other 17 patients (six NFL and 11 FL) had no reversibility of their bronchial obstruction (delta FEV1 <10% pred). In conclusion, patients with chronic obstructive pulmonary disease and expiratory flow limitation, even if nonresponders in terms of forced expiratory volume in one second, may benefit from bronchodilators because they can breathe, still in a flow-limited manner, at a lower lung volume.
Breathlessness in elderly individuals is related to low lung function and reversibility of airway obstruction
Authors: Boezen HM , Rijcken B , Schouten JP , Postma DS
Published: October 2002

The perception of breathlessness is a subject-related factor which is linked to respiratory disease, cardiac disease and overweight. We studied the distribution of breathlessness, its association with respiratory disease, cardiac disease and overweight, as well as its association with lung function, reversibility of airway obstruction ("reversibility") and peak expiratory flow (PEF) variability in an elderly population. Data on breathlessness (rated with Borg scale), lung function, reversibility, PEF variability, respiratory symptoms, cardiac disease and overweight were collected in a random sample of 210 elderly (>55 yrs old) who participated in a physical fitness test. Individuals with a Borg score >0 were taken to have breathlessness. Subjects with a Borg score >0 (n=50, 24%) were three to five times more likely to have a low lung function and large reversibility than subjects with a Borg score of zero, independent of the presence of respiratory symptoms, cardiac disease or overweight, although these three factors were all associated with low lung function and a large reversibility and PEF variability. Reversibility was not associated with PEF variability whatsoever. In elderly individuals, breathlessness is frequently present. Assessment of breathlessness using the Borg-scale seems an important clinical measurement, because it is an important independent predictor of lung function impairment in the elderly.