12,367 research outputs found
Synthesis and Stochastic Assessment of Cost-Optimal Schedules
We present a novel approach to synthesize good schedules for a class
of scheduling problems that is slightly more general than the
scheduling problem FJm,a|gpr,r_j,d_j|early/tardy. The idea is to prime
the schedule synthesizer with stochastic information more meaningful
than performance factors with the objective to minimize the expected
cost caused by storage or delay. The priming information is
obtained by stochastic simulation of the system environment. The generated
schedules are assessed again by simulation. The approach is
demonstrated by means of a non-trivial scheduling problem from
lacquer production. The experimental results show that our approach
achieves in all considered scenarios better results than the
extended processing times approach
Bounded Concurrent Timestamp Systems Using Vector Clocks
Shared registers are basic objects used as communication mediums in
asynchronous concurrent computation. A concurrent timestamp system is a higher
typed communication object, and has been shown to be a powerful tool to solve
many concurrency control problems. It has turned out to be possible to
construct such higher typed objects from primitive lower typed ones. The next
step is to find efficient constructions. We propose a very efficient wait-free
construction of bounded concurrent timestamp systems from 1-writer multireader
registers. This finalizes, corrects, and extends, a preliminary bounded
multiwriter construction proposed by the second author in 1986. That work
partially initiated the current interest in wait-free concurrent objects, and
introduced a notion of discrete vector clocks in distributed algorithms.Comment: LaTeX source, 35 pages; To apper in: J. Assoc. Comp. Mac
Randomized Two-Process Wait-Free Test-and-Set
We present the first explicit, and currently simplest, randomized algorithm
for 2-process wait-free test-and-set. It is implemented with two 4-valued
single writer single reader atomic variables. A test-and-set takes at most 11
expected elementary steps, while a reset takes exactly 1 elementary step. Based
on a finite-state analysis, the proofs of correctness and expected length are
compressed into one table.Comment: 9 pages, 4 figures, LaTeX source; Submitte
Market impacts and the life cycle of investors orders
In this paper, we use a database of around 400,000 metaorders issued by
investors and electronically traded on European markets in 2010 in order to
study market impact at different scales.
At the intraday scale we confirm a square root temporary impact in the daily
participation, and we shed light on a duration factor in with
. Including this factor in the fits reinforces the square
root shape of impact. We observe a power-law for the transient impact with an
exponent between (for long metaorders) and (for shorter ones).
Moreover we show that the market does not anticipate the size of the
meta-orders. The intraday decay seems to exhibit two regimes (though hard to
identify precisely): a "slow" regime right after the execution of the
meta-order followed by a faster one. At the daily time scale, we show price
moves after a metaorder can be split between realizations of expected returns
that have triggered the investing decision and an idiosynchratic impact that
slowly decays to zero.
Moreover we propose a class of toy models based on Hawkes processes (the
Hawkes Impact Models, HIM) to illustrate our reasoning.
We show how the Impulsive-HIM model, despite its simplicity, embeds appealing
features like transience and decay of impact. The latter is parametrized by a
parameter having a macroscopic interpretation: the ratio of contrarian
reaction (i.e. impact decay) and of the "herding" reaction (i.e. impact
amplification).Comment: 30 pages, 12 figure
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