2,023 research outputs found
Power Aware Wireless File Downloading: A Constrained Restless Bandit Approach
This paper treats power-aware throughput maximization in a multi-user file
downloading system. Each user can receive a new file only after its previous
file is finished. The file state processes for each user act as coupled Markov
chains that form a generalized restless bandit system. First, an optimal
algorithm is derived for the case of one user. The algorithm maximizes
throughput subject to an average power constraint. Next, the one-user algorithm
is extended to a low complexity heuristic for the multi-user problem. The
heuristic uses a simple online index policy and its effectiveness is shown via
simulation. For simple 3-user cases where the optimal solution can be computed
offline, the heuristic is shown to be near-optimal for a wide range of
parameters
Polyadic Entropy, Synergy and Redundancy among Statistically Independent Processes in Nonlinear Statistical Physics with Microphysical Codependence
The information shared among observables representing processes of interest
is traditionally evaluated in terms of macroscale measures characterizing
aggregate properties of the underlying processes and their interactions.
Traditional information measures are grounded on the assumption that the
observable represents a memoryless process without any interaction among
microstates. Generalized entropy measures have been formulated in non-extensive
statistical mechanics aiming to take microphysical codependence into account in
entropy quantification. By taking them into consideration when formulating
information measures, the question is raised on whether and if so how much
information permeates across scales to impact on the macroscale information
measures. The present study investigates and quantifies the emergence of
macroscale information from microscale codependence among microphysics. In
order to isolate the information emergence coming solely from the nonlinearly
interacting microphysics, redundancy and synergy are evaluated among macroscale
variables that are statistically independent from each other but not
necessarily so within their own microphysics. Synergistic and redundant
information are found when microphysical interactions take place, even if the
statistical distributions are factorable. These findings stress the added value
of nonlinear statistical physics to information theory in coevolutionary
systems
Phased models for evaluating the performability of computing systems
A phase-by-phase modelling technique is introduced to evaluate a fault tolerant system's ability to execute different sets of computational tasks during different phases of the control process. Intraphase processes are allowed to differ from phase to phase. The probabilities of interphase state transitions are specified by interphase transition matrices. Based on constraints imposed on the intraphase and interphase transition probabilities, various iterative solution methods are developed for calculating system performability
Delay-independent decentralised output feedback control for large-scale systems with nonlinear interconnections
In this paper, a stabilisation problem for a class of large-scale systems with nonlinear interconnections is considered. All the uncertainties are nonlinear and are subject to the effects of time delay. A decentralised static output feedback variable structure control is synthesised and the stability of the corresponding closed-loop system is analysed based on the Lyapunov Razumikhin approach. A set of conditions is developed to guarantee that the large-scale interconnected system is stabilised uniformly asymptotically. Further study shows that the conservatism can be reduced by employing additive controllers if the known interconnections are separated into matched and mismatched parts. It is not required that the subsystems are square. The designed controller is independent of time delay and thus it does not require memory. Simulation results show the effectiveness of the proposed approach
Source Coding with Fixed Lag Side Information
We consider source coding with fixed lag side information at the decoder. We
focus on the special case of perfect side information with unit lag
corresponding to source coding with feedforward (the dual of channel coding
with feedback) introduced by Pradhan. We use this duality to develop a linear
complexity algorithm which achieves the rate-distortion bound for any
memoryless finite alphabet source and distortion measure.Comment: 10 pages, 3 figure
Scalable Verification of Markov Decision Processes
Markov decision processes (MDP) are useful to model concurrent process
optimisation problems, but verifying them with numerical methods is often
intractable. Existing approximative approaches do not scale well and are
limited to memoryless schedulers. Here we present the basis of scalable
verification for MDPSs, using an O(1) memory representation of
history-dependent schedulers. We thus facilitate scalable learning techniques
and the use of massively parallel verification.Comment: V4: FMDS version, 12 pages, 4 figure
An identity of Chernoff bounds with an interpretation in statistical physics and applications in information theory
An identity between two versions of the Chernoff bound on the probability a
certain large deviations event, is established. This identity has an
interpretation in statistical physics, namely, an isothermal equilibrium of a
composite system that consists of multiple subsystems of particles. Several
information--theoretic application examples, where the analysis of this large
deviations probability naturally arises, are then described from the viewpoint
of this statistical mechanical interpretation. This results in several
relationships between information theory and statistical physics, which we
hope, the reader will find insightful.Comment: 29 pages, 1 figure. Submitted to IEEE Trans. on Information Theor
Communication cost of breaking the Bell barrier
Correlations in an Einstein-Podolsky-Rosen-Bohm experiment can be made
stronger than quantum correlations by allowing a single bit of classical
communication between the two sides of the experiment.Comment: One new reference referring to a maximal algebraic violation of the
Clauser-Horne-Shimony-Holt (CHSH) inequalit
Quantized Feedback Stabilization of Sampled-Data Switched Linear Systems
We propose a stability analysis method for sampled-data switched linear
systems with quantization. The available information to the controller is
limited: the quantized state and switching signal at each sampling time.
Switching between sampling times can produce the mismatch of the modes between
the plant and the controller. Moreover, the coarseness of quantization makes
the trajectory wander around, not approach, the origin. Hence the trajectory
may leave the desired neighborhood if the mismatch leads to instability of the
closed-loop system. For the stability of the switched systems, we develop a
sufficient condition characterized by the total mismatch time. The relationship
between the mismatch time and the dwell time of the switching signal is also
discussed.Comment: 17 pages, 3 figure
Distributed Robust Set-Invariance for Interconnected Linear Systems
We introduce a class of distributed control policies for networks of
discrete-time linear systems with polytopic additive disturbances. The
objective is to restrict the network-level state and controls to user-specified
polyhedral sets for all times. This problem arises in many safety-critical
applications. We consider two problems. First, given a communication graph
characterizing the structure of the information flow in the network, we find
the optimal distributed control policy by solving a single linear program.
Second, we find the sparsest communication graph required for the existence of
a distributed invariance-inducing control policy. Illustrative examples,
including one on platooning, are presented.Comment: 8 Pages. Submitted to American Control Conference (ACC), 201
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