New Class Of Systems Research Articles

Bridging the gap

The last few years have seen a burgeoning of p2p designs, but also a worrisome push back and skeptical resistance against much of this research (and development). We propose a new research direction that seeks to find common ground between the purely centralized architecture and the p2p systems. We propose a new class of systems called "P2P-izers" , which incentivize existing centralized infrastructures to utilize p2p solutions. A P2P-izer ensures that p2p technologies compliment existing centralized solutions. Finally, we show the feasibility of this direction by experimentally quantifying the advantages of a simple proof of concept P2P-izer solution for website hosting.

Automatic for the People

Probably the single biggest challenge with large scale systems and networks is not building them but rather managing them on an ongoing basis. Fortunately, new classes of systems and network management tools that have the potential to save on labor costs because they automate much of the management process are starting to appear.

Nosé-Hoover dynamics in a shaker

We introduce a new class of systems based on the Nose-Hoover equations. We show that we can add time-dependent terms without destroying the measure and energy conservation properties of the initial system. These "shakers" are typically pseudoperiodic in time, i.e., depend on a collection of harmonic oscillators. We show by numerical examples that it strengthens the sampling properties of the initial system with respect to the Gibbs measure and helps the computation of averages in the canonical ensemble.

Perceptual structure of the desired functionality of internet-based health information systems

With the emergence of the Internet, new health information systems are being designed and implemented that focus on coordination between providers, patients, payors and other constituents. While the importance of end user input in identifying the desired functionality of systems has long been recognized, very little work focuses on how users perceive the desired functionalities of these new systems to group together, and the implications of these groupings for the organization of functionalities into program modules and associated user interfaces. In this paper, we advance the construct, user based perceptual structure of desired functionality, in the context of these new coordination-intensive health information systems. Perceptual structure depicts how users perceive different desired system functions to group together. A conceptual framework is advanced which links perceptual structure to two broad categories of components, external coordination and internal coordination, which are related to prospective beliefs about system value. The framework is tested empirically via two field studies conducted by a hospital chain focusing on two major user groups, physicians and office administrators. The setting involves a proposed Internet-based health information system that links various constituencies in the service delivery chain. The empirically generated perceptual structure is found to be largely supportive of its conceptual counterpart. Implications for the design and development of this new class of systems, and public policy implications of such new systems are presented.

Systems of Hess-Appel’rot Type

We construct higher-dimensional generalizations of the classical Hess-Appel'rot rigid body system. We give a Lax pair with a spectral parameter leading to an algebro-geometric integration of this new class of systems, which is closely related to the integration of the Lagrange bitop performed by us recently and uses Mumford relation for theta divisors of double unramified coverings. Based on the basic properties satisfied by such a class of systems related to bi-Poisson structure, quasi-homogeneity, and conditions on the Kowalevski exponents, we suggest an axiomatic approach leading to what we call the "class of systems of Hess-Appel'rot type".

Distribution semigroups and control systems

We introduce the new concept of a distributional control system. This class of systems is the natural generalization of distribution semigroups to input/state/output systems. We showthat, under the Laplace transform, this new class of systems is equivalent to the class of distributional resolvent linear systems which we introduced in an earlier article. There we showed that this latter class of systems is the correct abstract setting in which to study many non-well-posed control systems such as the heat equation with Dirichlet control and Neumann observation. In this article we further show that any holomorphic function defined and polynomially bounded on some right half-plane can be realized as the transfer function of some exponentially bounded distributional resolvent linear system.

NOVEL SOUND PHENOMENA IN IMPURE SUPERFLUIDS

In the last decade, new techniques for producing impure superfluids with unique properties have been developed. This new class of systems includes superfluid helium confined to aerogel, HeII with different impurities, superfluids in Vycor glasses, and watergel. These systems exhibit very unusual properties including unexpected acoustic features. We discuss the sound properties of these systems and show that sound phenomena in impure superfluids are modified from those in pure superfluids. We calculate the coupling between temperature and pressure oscillations for impure superfluids and show that this coupling increases significantly. This leads to the existence in impure superfluids of such unusual sound phenomena as slow "pressure" waves and fast "temperature" waves. This also decreases the threshold values for nonlinear processes as compared to pure superfluids. Sound conversion, which has been observed in pure superfluids only by high intensity waves should be observed at moderate sound amplitude in impure superfluids. Cerenkov emission of second sound by first sound (which has never been observed in superfluids) could be observed in impure superfluids. Even the nature of the sound modes in impure superfluids turns out to be changed. We have also derived for the first time the nonlinear hydrodynamic equations for superfluid helium in aerogel.

Sensitivity analysis of solutions for a system of generalizedparametric nonlinear quasivariational inequalities

A new class of system of generalized parametric nonlinear quasivariational inequalities involving various classes of mappings is introduced and studied. With the properties of maximal monotone mappings, the equivalence between the class of system of generalized parametric nonlinear quasivariational inequalities and a class of fixed point problems is proved and an iterative algorithm with errors is constructed. A few existence and uniqueness results and sensitivity analysis of solutions are also established for the system of generalized nonlinear parametric quasivariational inequalities and some convergence results of iterative sequence generated by the algorithm with errors are proved.

Lower cost spatially immersive visualization for human environments

Access to computer simulation and computer based visualization has dramatically impacted our ability to design complex human environments. Immersive visualization, with its ability to present high quality interactive three-dimensional representations of environments, is the next step in this evolution. This paper explores the development of lower cost modular immersive visualization systems as a way to extend and augment our ability to plan, design and evaluate human environments. Technology now available enables spatially immersive visualization systems created using off the shelf components including high performance, relatively inexpensive, commodity computers, inexpensive commodity projectors and open source software. Flexible modular configurations utilizing polyhedral display surfaces with many identical modular components and networked visual computer clusters is one approach to such systems. Work is underway at the Texas A&M College of Architecture focused on developing and evaluating several prototypes of this new class of systems to determine their practicality and effectiveness. Underlying concepts, issues and trade-offs related to the design and development of these systems are presented. Initial applications using these systems in human environment planning, design and evaluation are discussed.

Return to return point memory.

We describe a new class of systems exhibiting return point memory (RPM), different from those discussed before in the context of ferromagnets. We show numerically that one-dimensional random Ising antiferromagnets have exact RPM when evolving from a large field, but not when started at finite field, unlike the ferromagnetic case. This implies that the standard approach to understanding ferromagnetic RPM will fail for this case. We also demonstrate RPM with a set of variables that keeps track of spin flips at each site. Conventional RPM for the spins is a projection of this result, suggesting that spin flip variables might be a more fundamental representation of the dynamics. We also present a mapping that embeds the antiferromagnetic chain in a two-dimensional ferromagnet, and prove RPM for spin-exchange dynamics in the interior of the chain with this mapping.

Novel sound phenomena in superfluid helium in aerogel and other impure superfluids

During the last decade new techniques for producing impure superfluids with unique properties have been developed. This new class of systems includes superfluid helium confined to aerogel, HeII with different impurities (D 2, N 2, Ne, Kr), superfluids in Vycor glasses, and watergel. These systems exhibit very unusual properties including unexpected acoustic features. We discuss the sound properties of these systems and show that sound phenomena in impure superfluids are modified from those in pure superfluids. We calculate the coupling between temperature and pressure oscillations for impure superfluids and for superfluid He in aerogel. We show that the coupling between these two sound modes is governed either by c∂ρ/ ∂c or σρ a ρ s (for aerogel) rather than thermal expansion coefficient ∂ρ/ ∂T, which is enormously small in pure superfluids. This replacement plays a fundamental role in all sound phenomena in impure superfluids. It enhances the coupling between the two sound modes that leads to the existence of such phenomena as the slow mode and heat pulse propagation with the velocity of first sound observed in superfluids in aerogel. This means that it is possible to observe in impure superfluids such unusual sound phenomena as slow pressure (density) waves and fast temperature (entropy) waves. The enhancement of the coupling between the two sound modes decreases the threshold values for nonlinear processes as compared to pure superfluids. Sound conversion, which has been observed in pure superfluids only by shock waves should be observed at moderate sound amplitude in impure superfluids. Čerenkov emission of second sound by first sound (which never been observed in pure superfluids) could be observed in impure superfluids.

The investigation into new integrable systems of equations in 2+1-dimensions

A new integrable class of systems of nonlinear partial differential equations (NPDEs) in 2+1 dimensions is derived from the matrix Nizhnik–Novikov–Veselov (NVV) equation by means of an asymptotically exact nonlinear reduction method based on Fourier expansion and spatio-temporal rescaling. The integrability by the inverse scattering method is explicitly demonstrated, by applying the reduction technique also to the Lax pair of the starting matrix equation and thereby obtaining the Lax pair for the new class of systems of equations. A reduction to a system of two interacting complex fields is briefly described.

An odd Furstenberg-Szemerédi theorem and quasi-affine systems

We prove a version of Furstenberg’s ergodic theorem with restrictions on return times. More specifically, for a measure preserving system (X, B, μ,T), integers 0 ≤j 0, we show that there existsn ≡ j (modk) with ώ(E ∩T-nE ∩T-2nE ∩T-3nE) > 0, so long asTk is ergodic. This result requires a deeper understanding of the limit of some nonconventional ergodic averages and the introduction of a new class of systems, the ‘Quasi-Affine Systems’.

A rational rank four demand system

AbstractPast parametric tests of demand system rank employed polynomial Engel curve systems. However, by Gorman's (1981) theorem, the maximum possible rank of a utility‐derived polynomial demand system is three. The present paper proposes a class of demand systems that are utility derived, are close to polynomial, and have rank four. These systems nest rational polynomial demands, and so can be used to test ranks up to four. These systems are suitable for applications where high rank is likely, such as demand systems involving a large number of goods. A test of rank using this new class of systems is applied to UK consumer demand data. Copyright © 2002 John Wiley & Sons, Ltd.

Quadratic stabilization of a collection of linear systems

The paper considers the problem of simultaneous quadratic (SQ) stablizability of a finite collection linear time-invariant (LTI) system by a static state feedback controller. At first, the solvability conditions for SQ stablization are derived in terms of the solution of certain reduced order matrix inequalities. The existence conditions for the solution of such matrix inequalities are then investigated. Based on that, two new classes of systems are characterized for which a SQ stabilization problem is solvable. These class of systems are (1) partially commutative systems and (2) partially normal systems. These systems are shown to be different from matched uncertain systems and also do not possess any generalised antisymmetric configurations. Both existence and computational algorithm for designing a state feedback controller are given.

Computing Lyapunov exponents on a Stiefel manifold

The problem of numerical computation of a few Lyapunov exponents (LEs) of finite-dimensional dynamical systems is considered from the viewpoint of the differential geometry of Stiefel manifolds. Whether one computes one, many or all LEs of a continuous dynamical system by time integration, discrete or continuous orthonormalization is essential for stable numerical integration. A differential-geometric view of continuous orthogonalization suggests that one restricts the linearized vectorfield to a Stiefel manifold. However, the Stiefel manifold is not in general an attracting submanifold of the ambient Euclidean space: it is a constraint manifold with a weak numerical invariant. New numerical algorithms for this problem are then designed which use the fiber-bundle characterization of these manifolds. This framework leads to a new class of systems for continuous orthogonalization which have strong numerical invariance properties and the strong skew-symmetry property. Numerical integration of these new systems with geometric integrators leads to a new class of numerical methods for computing a few LEs which preserve orthonormality to machine accuracy. This idea is also taken a step further by making the Stiefel manifold an attracting invariant manifold in which case standard explicit Runge–Kutta algorithms can be used. This leads to an algorithm which requires only marginally more computation than a standard explicit integration without orthogonalization. These class of methods should be particularly effective for computing a few LEs for large-dimension dynamical systems. The new schemes are straightforward to implement. A test case is presented for illustration, and an example from dynamical systems is presented where a few LEs are computed for an array of coupled oscillators.

Singular Perturbation Solutions of a Class of Systems of Singular Integral Equations

A new class of systems of strongly singular integrodifferential equations is examined, which emerges in the study of the bridged interface crack growth, e.g., in fiber stitched layered composites. This work generalizes the asymptotic analysis of strongly singular integral equations by Willis and Nemat-Nasser (Quart. Appl. Math., 48 (1990), pp. 741-753). Singular perturbation solutions up to the first-order in a small paramter are presented for a general case which corresponds to the elasticity problem of bridged interface cracks in general anisotropic bimaterials. In particular, detailed solutions are described for a special case which includes the problem of bridged interface cracks in isotropic bimaterials. Methods are illustrated by solving particular examples.

Designing the User Interface for Multimodal Speech and Pen-Based Gesture Applications: State-of-the-Art Systems and Future Research Directions

The growing interest in multimodal interface design is inspired in large part by the goals of supporting more transparent, flexible, efficient, and powerfully expressive means of human-computer interaction than in the past. Multimodal interfaces are expected to support a wider range of diverse applications, be usable by a broader spectrum of the average population, and function more reliably under realistic and challenging usage conditions. In this article, we summarize the emerging architectural approaches for interpreting speech and pen-based gestural input in a robust manner-including early and late fusion approaches, and the new hybrid symbolic-statistical approach. We also describe a diverse collection of state-of-the-art multimodal systems that process users' spoken and gestural input. These applications range from map-based and virtual reality systems for engaging in simulations and training, to field medic systems for mobile use in noisy environments, to web-based transactions and standard text-editing applications that will reshape daily computing and have a significant commercial impact. To realize successful multimodal systems of the future, many key research challenges remain to be addressed. Among these challenges are the development of cognitive theories to guide multimodal system design, and the development of effective natural language processing, dialogue processing, and error-handling techniques. In addition, new multimodal systems will be needed that can function more robustly and adaptively, and with support for collaborative multiperson use. Before this new class of systems can proliferate, toolkits also will be needed to promote software development for both simulated and functioning systems.

Design of static output feedback controller for uncertain systems

This paper considers the problem of designing a single static output feedback stabilizing controller for a finite set of linear systems. For this purpose, a set of square (equal number of inputs and outputs) minimum phase systems is considered. Using the notions of quadratic stabilizability, the existence of output feedback controller is derived in terms of the solvability of a set of matrix inequalities. Then the existence of the solution of such inequalities are derived for special class of systems. It is proved that a set of partially commutative or partially normal systems are stabilizable by a single static output feedback controller. These classes of systems are shown to be different from the well-known matched uncertain systems and considered to be new classes of systems. An algorithm is also presented to compute the controller gain.

CORRECT DIAGNOSIS OF ALMOST ALL FAULTY UNITS IN A MULTIPROCESSOR SYSTEM

In a t/t-diagnosable system, all faulty units can be located to within a set of no more than t units as long as the number of faulty units present does not exceed t. Furthermore, a unique doubtful unit can be identified; in other words, all faulty units, except possibly for one, can be correctly identified in a t/t-diagnosable system. An open question is "Is t/t-diagnosability necessary for correctly identifying all but one faulty unit?" In this paper, we address the above question and provide an answer. We establish necessary and sufficient conditions for correct diagnosis of all except possibly one faulty unit. In addition, we show that the fault-free state is indistinguishable from a faulty state in a t/t-diagnosable system and propose a remedy. These considerations result in the definition and characterization of a new class of systems called t/-1 diagnosable systems.