627,020 research outputs found
Static Analysis of Deterministic Negotiations
Negotiation diagrams are a model of concurrent computation akin to workflow
Petri nets. Deterministic negotiation diagrams, equivalent to the much studied
and used free-choice workflow Petri nets, are surprisingly amenable to
verification. Soundness (a property close to deadlock-freedom) can be decided
in PTIME. Further, other fundamental questions like computing summaries or the
expected cost, can also be solved in PTIME for sound deterministic negotiation
diagrams, while they are PSPACE-complete in the general case.
In this paper we generalize and explain these results. We extend the
classical "meet-over-all-paths" (MOP) formulation of static analysis problems
to our concurrent setting, and introduce Mazurkiewicz-invariant analysis
problems, which encompass the questions above and new ones. We show that any
Mazurkiewicz-invariant analysis problem can be solved in PTIME for sound
deterministic negotiations whenever it is in PTIME for sequential
flow-graphs---even though the flow-graph of a deterministic negotiation diagram
can be exponentially larger than the diagram itself. This gives a common
explanation to the low-complexity of all the analysis questions studied so far.
Finally, we show that classical gen/kill analyses are also an instance of our
framework, and obtain a PTIME algorithm for detecting anti-patterns in
free-choice workflow Petri nets.
Our result is based on a novel decomposition theorem, of independent
interest, showing that sound deterministic negotiation diagrams can be
hierarchically decomposed into (possibly overlapping) smaller sound diagrams.Comment: To appear in the Proceedings of LICS 2017, IEEE Computer Societ
Jet analysis by Deterministic Annealing
We perform a comparison of two jet clusterization algorithms. The first one
is the standard Durham algorithm and the second one is a global optimization
scheme, Deterministic Annealing, often used in clusterization problems, and
adapted to the problem of jet identification in particle production by high
energy collisions; in particular we study hadronic jets in WW production by
high energy electron positron scattering. Our results are as follows. First, we
find that the two procedures give basically the same output as far as the
particle clusterization is concerned. Second, we find that the increase of CPU
time with the particle multiplicity is much faster for the Durham jet
clustering algorithm in comparison with Deterministic Annealing. Since this
result follows from the higher computational complexity of the Durham scheme,
it should not depend on the particular process studied here and might be
significant for jet physics at LHC as well.Comment: 15 pages, 4 figure
The human ECG - nonlinear deterministic versus stochastic aspects
We discuss aspects of randomness and of determinism in electrocardiographic
signals. In particular, we take a critical look at attempts to apply methods of
nonlinear time series analysis derived from the theory of deterministic
dynamical systems. We will argue that deterministic chaos is not a likely
explanation for the short time variablity of the inter-beat interval times,
except for certain pathologies. Conversely, densely sampled full ECG recordings
possess properties typical of deterministic signals. In the latter case,
methods of deterministic nonlinear time series analysis can yield new insights.Comment: 6 pages, 9 PS figure
Improved Analysis of Deterministic Load-Balancing Schemes
We consider the problem of deterministic load balancing of tokens in the
discrete model. A set of processors is connected into a -regular
undirected network. In every time step, each processor exchanges some of its
tokens with each of its neighbors in the network. The goal is to minimize the
discrepancy between the number of tokens on the most-loaded and the
least-loaded processor as quickly as possible.
Rabani et al. (1998) present a general technique for the analysis of a wide
class of discrete load balancing algorithms. Their approach is to characterize
the deviation between the actual loads of a discrete balancing algorithm with
the distribution generated by a related Markov chain. The Markov chain can also
be regarded as the underlying model of a continuous diffusion algorithm. Rabani
et al. showed that after time , any algorithm of their
class achieves a discrepancy of , where is the spectral
gap of the transition matrix of the graph, and is the initial load
discrepancy in the system.
In this work we identify some natural additional conditions on deterministic
balancing algorithms, resulting in a class of algorithms reaching a smaller
discrepancy. This class contains well-known algorithms, eg., the Rotor-Router.
Specifically, we introduce the notion of cumulatively fair load-balancing
algorithms where in any interval of consecutive time steps, the total number of
tokens sent out over an edge by a node is the same (up to constants) for all
adjacent edges. We prove that algorithms which are cumulatively fair and where
every node retains a sufficient part of its load in each step, achieve a
discrepancy of in time . We
also show that in general neither of these assumptions may be omitted without
increasing discrepancy. We then show by a combinatorial potential reduction
argument that any cumulatively fair scheme satisfying some additional
assumptions achieves a discrepancy of almost as quickly as the
continuous diffusion process. This positive result applies to some of the
simplest and most natural discrete load balancing schemes.Comment: minor corrections; updated literature overvie
The Revised Model State Administrative Procedure Act—Reform or Retrogression?
In this contribution, we deal with the deterministic dominance of the probability moments of stochastic processes. More precisely, given a positive stochastic process, we propose to dominate its probability moment sequence by the trajectory of appropriate lower and upper dominating deterministic processes. The analysis of the behavior of the original stochastic process is then transferred to the stability analysis of the deterministic dominating processes. The result is applied to a nonstationary auto-regressive process that appears in the system identification literature.
Complexity Theory and the Operational Structure of Algebraic Programming Systems
An algebraic programming system is a language built from a fixed algebraic data abstraction and a selection of deterministic, and non-deterministic, assignment and control constructs. First, we give a detailed analysis of the operational structure of an algebraic data type, one which is designed to classify programming systems in terms of the complexity of their implementations. Secondly, we test our operational description by comparing the computations in deterministic and non-deterministic programming systems under certain space and time restrictions
Free Deterministic Equivalents for the Analysis of MIMO Multiple Access Channel
In this paper, a free deterministic equivalent is proposed for the capacity
analysis of the multi-input multi-output (MIMO) multiple access channel (MAC)
with a more general channel model compared to previous works. Specifically, a
MIMO MAC with one base station (BS) equipped with several distributed antenna
sets is considered. Each link between a user and a BS antenna set forms a
jointly correlated Rician fading channel. The analysis is based on
operator-valued free probability theory, which broadens the range of
applicability of free probability techniques tremendously. By replacing
independent Gaussian random matrices with operator-valued random variables
satisfying certain operator-valued freeness relations, the free deterministic
equivalent of the considered channel Gram matrix is obtained. The Shannon
transform of the free deterministic equivalent is derived, which provides an
approximate expression for the ergodic input-output mutual information of the
channel. The sum-rate capacity achieving input covariance matrices are also
derived based on the approximate ergodic input-output mutual information. The
free deterministic equivalent results are easy to compute, and simulation
results show that these approximations are numerically accurate and
computationally efficient.Comment: 26 pages, 7 figures, Accepted by IEEE Transactions on Information
Theor
Efficiency of Deterministic Entanglement Transformation
We prove that sufficiently many copies of a bipartite entangled pure state
can always be transformed into some copies of another one with certainty by
local quantum operations and classical communication. The efficiency of such a
transformation is characterized by deterministic entanglement exchange rate,
and it is proved to be always positive and bounded from top by the infimum of
the ratios of Renyi's entropies of source state and target state. A careful
analysis shows that the deterministic entanglement exchange rate cannot be
increased even in the presence of catalysts. As an application, we show that
there can be two incomparable states with deterministic entanglement exchange
rate strictly exceeding 1.Comment: 7 pages, RevTex4. Journal versio
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