Genuine correlations of tripartite system

We define genuine total, classical and quantum correlations in tripartite systems. The genuine tripartite quantum discord can be interpreted as ‘quantum advantage’ in tripartite superdense coding. We find in a symmetrical tripartite state, for total correlation and classical correlation, the genuine tripartite correlations are no less than the pair-wise correlations. However, the genuine quantum tripartite correlation can be surpassed by the pair-wise quantum correlations. Analytical expressions for genuine tripartite correlations are obtained for pure states and rank-2 symmetrical states. The genuine correlations in both entangled and separable states are calculated.     

Switched mode feedback control laws for nonholonomic systems in extended power form

A class of nonholonomic control systems in extended power form is studied. It is demonstrated that under appropriate assumptions Lagrange's equations, including classical nonholonomic constraints, can be transformed into the extended power form. A switched mode feedback controller is used to obtain global convergence of the states of the extended power form to the origin. This feedback controller can be interpreted as a hybrid system consisting of a high level discrete event supervisor and a family of low level feedback controllers. The closed loop system exhibits finite-time responses.     

Non-Markovian dynamics of quantum coherence of two-level system driven by classical field

In this paper, we study the quantum coherence dynamics of two-level atom system embedded in non-Markovian reservoir in the presence of classical driving field. We analyze the influence of memory effects, classical driving, and detuning on the quantum coherence. It is found that the quantum coherence has different behaviors in resonant case and non-resonant case. In the resonant case, in stark contrast with previous results, the strength of classical driving plays a negative effect on quantum coherence, while detuning parameter has the opposite effect. However, in non-resonant case through a long time, classical driving and detuning parameter have a different influence on quantum coherence compared with resonant case. Due to the memory effect of environment, in comparison with Markovian regime, quantum coherence presents vibrational variations in non-Markovian regime. In the resonant case, all quantum coherence converges to a fixed maximum value; in the non-resonant case, quantum coherence evolves to different stable values. For zero-coherence initial states, quantum coherence can be generated with evolution time. Our discussions and results should be helpful in manipulating and preserving the quantum coherence in dissipative environment with classical driving field.     

Proof Transformation via Interpretation Functions: Results, Problems and Applications

Change is a constant factor in Software Engineering process. Redesign of a class structure requires transformation of the corresponding OCL constraints. In a previous paper we have shown how to use, what we call, interpretation functions for transformation of constraints. In this paper we discuss recently obtained results concerning proof transformations via such functions. In particular we detail the fact that they preserve proofs in equational logic, as well as proofs in other logical systems like propositional logic with modus ponens or proofs using resolution rule. Those results have direct applications to redesign of UML State Machines and Sequence Diagrams. If states in a State Machine are interpreted by State Invariants, then the topological relations between its states can be interpreted as logical relations between the corresponding formulas. Preservation of the consequence relation can bee seen as preservation of the topology of State Machines. We indicate also an unsolved problem and discuss the mining of its positive solution.     

Quantified epistemic logics for reasoning about knowledge in multi-agent systems

We introduce quantified interpreted systems, a semantics to reason about knowledge in multi-agent systems in a first-order setting. Quantified interpreted systems may be used to interpret a variety of first-order modal epistemic languages with global and local terms, quantifiers, and individual and distributed knowledge operators for the agents in the system. We define first-order modal axiomatisations for different settings, and show that they are sound and complete with respect to the corresponding semantical classes.The expressibility potential of the formalism is explored by analysing two MAS scenarios: an infinite version of the muddy children problem, a typical epistemic puzzle, and a version of the battlefield game. Furthermore, we apply the theoretical results here presented to the analysis of message passing systems [R. Fagin, J. Halpern, Y. Moses, M. Vardi, Reasoning about Knowledge, MIT Press, 1995; L. Lamport, Time, clocks, and the ordering of events in a distributed system, Communication of the ACM 21 (7) (1978) 558–565], and compare the results obtained to their propositional counterparts. By doing so we find that key known meta-theorems of the propositional case can be expressed as validities on the corresponding class of quantified interpreted systems.     

The interpretation of discontinuous state feedback control laws as nonanticipative control strategies in differential games

In differential games, one player chooses a feedback strategy to maximize a payoff. The other player counters by applying a minimizing open loop control. Classical notions of feedback strategies, based on state feedback control laws for which the corresponding closed loop dynamics uniquely define a state trajectory, are too restrictive for many problems, owing to the absence of minimizing classical feedback strategies or because consideration of classical feedback strategies fails to define, in a useful way, the value of the game. A number of feedback strategy concepts have been proposed to overcome this difficulty. That of Elliot and Kalton, according to which a feedback strategy is a nonanticipative mapping between control functions for the two players, has been widely taken up because it provides a value of the game which connects, via the Hamilton-Jacobi-Isaacs equation, with other fields of systems science. Heuristic analysis of specific games problems often points to discontinuous optimal feedback strategies. These cannot be regarded as classical feedback control strategies because the associated state trajectories are not in general unique. We give general conditions under which they can be interpreted as generalized feedback strategies in the sense of Elliot and Kalton.     

Averaged control

We analyze the problem of controlling parameter-dependent systems. We introduce the notion of averaged control according to which the quantity of interest is the average of the states with respect to the parameter.First we consider the problem of controllability for linear finite-dimensional systems and show that a necessary and sufficient condition for averaged controllability is an averaged rank condition, in the spirit of the classical rank condition for linear control systems, but involving averaged momenta of any order of the matrices generating the dynamics and representing the control action.We also describe some open problems and directions of possible research, in particular on the average controllability of evolution partial differential equations. In this context we analyze also the averaged version of a classical optimal control problem for a parameter dependent elliptic equation and derive the corresponding optimality system.     

Generation of entangled coherent-squeezed states: their entanglement and nonclassical properties

In this paper, after a brief review on the coherent states and squeezed states, we introduce two classes of entangled coherent-squeezed states. Next, in order to generate the introduced entangled states, we present a theoretical scheme based on the resonant atom-field interaction. In the proposed model, a \(\varLambda \)-type three-level atom interacts with a two-mode quantized field in the presence of two strong classical fields. Then, we study the amount of entanglement of the generated entangled states using the concurrence and linear entropy. Moreover, we evaluate a few of their nonclassical properties such as photon statistics, second-order correlation function, and quadrature squeezing and establish their nonclassicality features.     

Entanglement sudden death: a threat to advanced quantum key distribution?

Entanglement is a global characteristic unique to quantum states that depends on quantum coherence and may allow one to carry out communications and information processing tasks that are either impossible or less efficient using classical states. Because environmental noise, even when entirely local in spatial extent, can fully destroy entanglement in finite time, an effect referred to as “entanglement sudden death” (ESD), it may threaten quantum information processing tasks. Although it may be possible to “distill” entanglement from a collection of noise-affected systems under appropriate circumstances, once entanglement has been completely lost no amount of distillation can recover it. It is therefore extremely important to avoid its complete destruction in times comparable to those of information processing tasks. Here, the effect of local noise on a class of entangled states used in entanglement-based quantum key distribution is considered and the threat ESD might pose to it is assessed.     

Computation of the resonant frequency of electrically thin and thick rectangular microstrip antennas with the use of fuzzy inference systems

A new method for calculating the resonant frequency of electrically thin and thick rectangular microstrip antennas, based on the fuzzy inference systems, is presented. The optimum design parameters of the fuzzy inference systems are determined by using the classical, modified, and improved tabu search algorithms. The calculated resonant frequency results are in very good agreement with the experimental results reported elsewhere. © 2000 John Wiley & Sons, Inc. Int J RF and Microwave CAE 10: 108–119, 2000.     

Towards Approximation of Equilibrium States in Nonadditive Lattice Systems

We propose a framework for solving the problem of approximation of equilibrium-like like states in one-dimensional classical lattice systems with superadditive Hamiltonians. Systems of this type arise naturally in the generalisation of thermodynamic formalism dealing with the dynamics generated by nonconformal maps, [4,5]. It is known that although a generalised version of variational principle holds for such systems, equilibrium states may not exist in general. Our approach is to characterise approximately equilibrium states by linear functionals bounded by free energy on a suitable Banach space of Hamiltonians. We construct a map binding states on the algebra of observables with linear functionals on the space of (nonadditive) Hamiltonians and study its basic properties.     

Identification of noncontrollable systems from impulse response measurements

We analyze the problem of modeling an observed impulse response by means of a finite-dimensional, linear, time-invariant system. Our approach differs from classical realization theory in the following respects. The modeling problem is split in two steps, namely, identification for determining a model for the observations, and realization for determining parameters which describe the model. Systems are considered as sets of time series, not as input-output maps. In particular, the partitioning of variables into inputs and outputs need not be known, and it is not required that there exist a causal relationship between inputs and outputs. Further, we make no assumptions concerning initial conditions, which in particular may be nonzero. Determination of initial conditions is part of the modeling problem. A final significant distinction from classical realization theory is that the systems need not be controllable.We characterize the class of systems which can be identified from impulse response measurements. Necessary and sufficient conditions are formulated in terms of state-space realizations. It turns out that noncontrollable systems are also identifiable. For causal systems, the condition is that the state transition matrix, restricted to the noncontrollable states, has sufficiently small cyclic index. For noncausal systems, the condition is expressed in terms of the rank of the (singular) state evolution equation.     

Brain state in a convex body

We study a generalization of the brain-state-in-a-box (BSB) model for a class of nonlinear discrete dynamical systems where we allow the states of the system to lie in an arbitrary convex body. The states of the classical BSB model are restricted to lie in a hypercube. Characterizations of equilibrium points of the system are given using the support function of a convex body. Also, sufficient conditions for a point to be a stable equilibrium point are investigated. Finally, we study the system in polytopes. The results in this special case are more precise and have simpler forms than the corresponding results for general convex bodies. The general results give one approach of allowing pixels in image reconstruction to assume more than two values.     

Implementation of a declarative state-transition system

A declarative programming style is claimed to have significant advantages from a software engineering point of view. However, these benefits cannot generally be realized when writing programs that are concerned with changing state, such as environments and programming tools. Declarative state-transition (DST) systems have been proposed as a solution to this problem. In DST systems, computation and update are separated. Programs are interpreted as defining functions or relations over states, and update follows successful computation of new states. Support for persistent state and atomic, serializable transactions facilitates the implementation of programming environments and tools. This paper describes an implementation scheme for DST systems. The scheme is illustrated by a presentation of the implementation of PPS, a DST system for parallel logic programming.     

Model predictive control of resonant systems using Kautz model

The scope of this paper broadly spans in two areas: system identification of resonant system and design of an efficient control scheme suitable for resonant systems. Use of filters based on orthogonal basis functions (OBF) have been advocated for modelling of resonant process. Kautz filter has been identified as best suited OBF for this purpose. A state space based system identification technique using Kautz filters, viz. Kautz model, has been demonstrated. Model based controllers are believed to be more efficient than classical controllers because explicit use of process model is essential with these modelling techniques. Extensive literature search concludes that very few reports are available which explore use of the model based control studies on resonant system. Two such model based controllers are considered in this work, viz. model predictive controller and internal model controller. A model predictive control algorithm has been developed using the Kautz model. The efficacy of the model and the controller has been verified by two case studies, viz. linear second order underdamped process and a mildly nonlinear magnetic ball suspension system. Comparative assessment of performances of these controllers in those case studies have been carried out.     

Neural networks with quantum gated nodes

With a view to investigating similarities in aspects of biological neural networks with quantum ones, so that quantum machines can be developed in future with some of the advantages of biological systems of information processing where a certain amount of indeterminism and the multiple connectivities between nodes offer advantages not seemingly obtainable from usual electronic devices working with classical gates, we present here some results for a quantum neural network with quantum gates. After reviewing the general principles of a biological network and a quantum one, we study a specific model network with qubits, i.e. quantum bits, replacing classical neurons having deterministic states, and also with quantum operators in place of the classical action potentials observed in biological contexts. With our choice of gates interconnecting the neural lattice, the state of the system behaves in ways reflecting both the strength of coupling between neurons as well as the initial conditions, as in biological systems. We find that, depending on whether there is a threshold for emission from excited to ground state, the system shows either chaotic oscillations or coherent ones with periodicity that depends on the strength of coupling. The initial input also affects the subsequent dynamic behavior of the system, which indicates that it can serve as a dynamic memory system analogous to biological ones. Our results seem to suggest that such quantum networks may contain some advantageous features of biological systems more efficiently than classical electronic devices.     

Axioms for classical, intuitionistic, and paraconsistent hybrid logic

In this paper we give axiom systems for classical and intuitionistic hybrid logic. Our axiom systems can be extended with additional rules corresponding to conditions on the accessibility relation expressed by so-called geometric theories. In the classical case other axiomatisations than ours can be found in the literature but in the intuitionistic case no axiomatisations have been published. We consider plain intuitionistic hybrid logic as well as a hybridized version of the constructive and paraconsistent logic N4.     

Environments to support context and emotion aware visual interaction

The interaction with software systems is often affected by many types of hurdles that induce users to make errors and mistakes, and to break the continuity of their reasoning while carrying out a working task with the computer. As a consequence, negative emotional states, such as frustration, dissatisfaction, and anxiety, may arise. In this paper, we illustrate how the Software Shaping Workshop (SSW) methodology can represent a solution to the problem of developing interactive systems that are correctly perceived and interpreted by end-users, thus becoming more acceptable and favouring positive emotional states. In the methodology, a key role is played by domain-expert users, that is, experts in a specific domain, not necessarily experts in computer science. Domain-expert users’ skills and background, including their knowledge of the domain and users’ needs and habits, are exploited to create context and emotion aware visual interactive systems. Examples of these systems are illustrated by referring to a case study in the automation field.     

H∞ control for discrete‐time nonlinear switching systems

This paper formulates and solves the robust H^∞ control problem for discrete‐time nonlinear switching systems. The H^∞ control problem is interpreted as the l₂ finite gain control problem and is studied using a dissipative systems theory for switched systems. Both state and measurement feedback control problems are formulated as dynamic games and solved using dynamic programming. The partially observed dynamic game corresponding to the measurement feedback control problem is solved by transforming into a completely observed, full state infinite‐dimensional game problem using information states. Our results are illustrated with an example. Copyright © 2007 John Wiley & Sons, Ltd.     

Estimates for discontinuity jumps of information characteristics of quantum systems and channels

Quantitative analysis of discontinuity of information characteristics of quantum states and channels is presented. Estimates for discontinuity jump (loss) of the von Neumann entropy for a given converging sequence of states are obtained. It is shown, in particular, that for any sequence the loss of entropy is upper bounded by the loss of mean energy (with the coefficient characterizing the Hamiltonian of a system). Then we prove that discontinuity jumps of basic measures of classical and quantum correlations in composite quantum systems are upper bounded by the loss of one of the marginal entropies (with a corresponding coefficient). Quantitative discontinuity analysis of the output entropy of a quantum operation and of basic information characteristics of a quantum channel considered as functions of a pair (channel, input state) is presented.