118 research outputs found
The Use of Marginal Energy Costs in the Design of U.S. Capacity Markets
This paper surveys the development of marginal cost theories used in the optimal allocation of scarce resources, and examines the application of these theories to current-day electricity capacity markets. The different approaches in use today to ensure grid reliability and incentivize new resources are examined. Market challenges are surveyed, as well as empirical findings that suggest that current market approaches do not provide proper incentives. We conclude that the so-called missing money is not missing because of defects in market designs, or so-called administrative actions---money to incentivize investments is missing due to a misapplication of marginal cost theory
Markov Chain Monte Carlo Method without Detailed Balance
We present a specific algorithm that generally satisfies the balance
condition without imposing the detailed balance in the Markov chain Monte
Carlo. In our algorithm, the average rejection rate is minimized, and even
reduced to zero in many relevant cases. The absence of the detailed balance
also introduces a net stochastic flow in a configuration space, which further
boosts up the convergence. We demonstrate that the autocorrelation time of the
Potts model becomes more than 6 times shorter than that by the conventional
Metropolis algorithm. Based on the same concept, a bounce-free worm algorithm
for generic quantum spin models is formulated as well.Comment: 5 pages, 5 figure
Stationarity and Geometric Ergodicity of BEKK Multivariate GARCH Models
Conditions for the existence of strictly stationary multivariate GARCH
processes in the so-called BEKK parametrisation, which is the most general form
of multivariate GARCH processes typically used in applications, and for their
geometric ergodicity are obtained. The conditions are that the driving noise is
absolutely continuous with respect to the Lebesgue measure and zero is in the
interior of its support and that a certain matrix built from the GARCH
coefficients has spectral radius smaller than one.
To establish the results semi-polynomial Markov chains are defined and
analysed using algebraic geometry.Comment: version to appear in Stochastic Processes and their Applications,
2011; http://www.sciencedirect.com/science/article/pii/S030441491100137
On the flow-level stability of data networks without congestion control: the case of linear networks and upstream trees
In this paper, flow models of networks without congestion control are
considered. Users generate data transfers according to some Poisson processes
and transmit corresponding packet at a fixed rate equal to their access rate
until the entire document is received at the destination; some erasure codes
are used to make the transmission robust to packet losses. We study the
stability of the stochastic process representing the number of active flows in
two particular cases: linear networks and upstream trees. For the case of
linear networks, we notably use fluid limits and an interesting phenomenon of
"time scale separation" occurs. Bounds on the stability region of linear
networks are given. For the case of upstream trees, underlying monotonic
properties are used. Finally, the asymptotic stability of those processes is
analyzed when the access rate of the users decreases to 0. An appropriate
scaling is introduced and used to prove that the stability region of those
networks is asymptotically maximized
Sparse and Constrained Stochastic Predictive Control for Networked Systems
This article presents a novel class of control policies for networked control
of Lyapunov-stable linear systems with bounded inputs. The control channel is
assumed to have i.i.d. Bernoulli packet dropouts and the system is assumed to
be affected by additive stochastic noise. Our proposed class of policies is
affine in the past dropouts and saturated values of the past disturbances. We
further consider a regularization term in a quadratic performance index to
promote sparsity in control. We demonstrate how to augment the underlying
optimization problem with a constant negative drift constraint to ensure
mean-square boundedness of the closed-loop states, yielding a convex quadratic
program to be solved periodically online. The states of the closed-loop plant
under the receding horizon implementation of the proposed class of policies are
mean square bounded for any positive bound on the control and any non-zero
probability of successful transmission
Veröffentlichungen aus dem Staatsarchiv der Freien und Hansestadt Hamburg
Das Staatsarchiv Hamburg feierte 2010 sein 300-jÀhriges Bestehen.
Sein VorlÀufer wurde bereits im Jahre 1293 erstmals erwÀhnt und somit die Aufbewahrung wichtiger Dokumente der Stadt an zentraler Stelle bezeugt. Doch erst seit dem 11. September 1710, dem Amtsantritt von Nicolaus Stampeel als wissenschaftlicher Archivar bei der Stadt Hamburg, werden Dokumente systematisch ausgewÀhlt, bewahrt und erschlossen.
Dieses JubilÀum hat das Staatsarchiv mit einem breit gefÀcherten Veranstaltungsprogramm begangen, zu dem auch VortrÀge und Lesungen gehörten, die in der hier vorliegenden Festschrift abgedruckt sind.In 2010, the Hamburg State Archives celebrated its 300th anniversary. The Archives\u27 forerunner was first mentioned in 1293 and thus testified to the preservation of important documents of the city in a central place. But it was not until September 11th, 1710, when Nicolaus Stampeel took office as a scientific archivist at the City of Hamburg. From then on, documents were systematically selected, preserved and indexed.
This anniversary was celebrated by the State Archives with a broad programme of events, which included lectures and readings printed in the commemorative volume available here
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