19,919 research outputs found
A NOTE ON COMONOTONICITY AND POSITIVITY OF THE CONTROL COMPONENTS OF DECOUPLED QUADRATIC FBSDE
In this small note we are concerned with the solution of Forward-Backward
Stochastic Differential Equations (FBSDE) with drivers that grow quadratically
in the control component (quadratic growth FBSDE or qgFBSDE). The main theorem
is a comparison result that allows comparing componentwise the signs of the
control processes of two different qgFBSDE. As a byproduct one obtains
conditions that allow establishing the positivity of the control process.Comment: accepted for publicatio
Finitely generated ideal languages and synchronizing automata
We study representations of ideal languages by means of strongly connected
synchronizing automata. For every finitely generated ideal language L we
construct such an automaton with at most 2^n states, where n is the maximal
length of words in L. Our constructions are based on the De Bruijn graph.Comment: Submitted to WORDS 201
Piezoelectric actuators for bone mechanical stimulation: exploring the concept.
Arthroplasty is liable to cause intense changes on strain levels and distribution in the boné surrounding the implant, namely stress shielding. Several solutions have been proposed for this, namely design variations and development of controlled-stiffness implants. A new approach to this problem, with potential application to other orthopaedic problems and other medical fields, would be the development of smart implants integrating systems for bone mechanical stimulation. Ideally, the implant should presente sensing capability and the ability to maintain physiological levels of strain at the implant interface. Piezoelectric materials’ huge potential as a mean to produce direct mechanical stimulation lies on the possibility of producing stimuli at a high range of frequencies and in multiple combinations. The present in vitro and preliminary in vivo studies were a first step towards the validation of the concept
Bone mechanical stimulation with piezoelectric materials
This chapter summarized explores in vivo use of a piezoelectric
polymer for bone mechanical stimulatio
Testing the Equivalence of Regular Languages
The minimal deterministic finite automaton is generally used to determine
regular languages equality. Antimirov and Mosses proposed a rewrite system for
deciding regular expressions equivalence of which Almeida et al. presented an
improved variant. Hopcroft and Karp proposed an almost linear algorithm for
testing the equivalence of two deterministic finite automata that avoids
minimisation. In this paper we improve the best-case running time, present an
extension of this algorithm to non-deterministic finite automata, and establish
a relationship between this algorithm and the one proposed in Almeida et al. We
also present some experimental comparative results. All these algorithms are
closely related with the recent coalgebraic approach to automata proposed by
Rutten
Modified Bristow-Latarjet procedure for treatment of recurrent traumatic anterior glenohumeral dislocation
Retrospective case-control study of authors experience in the modified Bristow-Latarjet procedure for treatment of recurrent traumatic anterior glenohumeral dislocation with glenoid bone injury.info:eu-repo/semantics/publishedVersio
Initial measurements of black hole spin in GX 339-4 from Suzaku spectroscopy
We report on a deep Suzaku observation of the stellar-mass black hole GX 339-4 in outburst. A clear, strong, relativistically shaped iron emission line from the inner accretion disk is observed. The broadband disk reflection spectrum revealed is one of the most sensitive yet obtained from an accreting black hole. We fit the Suzaku spectra with a physically motivated disk reflection model, blurred by a new relativistic line function in which the black hole spin parameter is a variable. This procedure yielded a black hole spin parameter of a p. Joint modeling of these Suzaku spectra and prior XMM-Newton spectra obtained in two different 0.89 +/- 0.04 outburst phases yields a spin parameter of a = 0.93 +/- 0.01. The degree of consistency between these results suggests that disk reflection models allow for spin measurements that are not strongly biased by scattering effects. We suggest that the best value of the black hole spin parameter is a = 0.93 +/- 0.01 (statistical) +/- 0.04 (systematic). Although preliminary, these results represent the first direct measurement of nonzero spin in a stellar-mass black hole using relativistic line modeling
Assessing software development teams' efficiency using process mining
Context. Improving the efficiency and effectiveness of software development projects implies understanding their actual process. Given the same requirements specification, different software development teams may follow different strategies and that may lead to inappropriate use of tools or non-optimized allocation of effort on spurious activities, non-aligned with the desired goals. However, due to its intangibility, the actual process followed by each developer or team is often a black box.
Objective. The overall goal of this study is to improve the knowledge on how to measure efficiency in development teams where a great deal of variability may exist due to the humanfactor. The main focus is on the discovery of the underlying processes and compare them in terms of efficiency and effectiveness. By doing so, we expect to reveal potentially hidden costs and risks, so that corrective actions may take place on a timely manner during the software project life cycle.
Method. Several independent teams of Java programmers, using the Eclipse IDE, were assigned the same software quality task, related to code smells detection for identifying refactoring opportunities and the quality of the outcomes were assessed by independent experts. The events corresponding to the activity of each team upon the IDE, while performing the given task, were captured. Then, we used process mining techniques to discover development process models, evaluate their quality and compare variants against a reference model used as ”best practice”.
Results. Teams whose process model was less complex, had the best outcomes and vice-versa. Comparing less complex process variants with the ”best practice” process, showed that they were also the ones with less differences in the control-flow perspective, based on activities frequencies. We have also determined which teams were most efficient through process analysis.
Conclusions. We confirmed that, even for a well-defined software development task, there may be a great deal of process variability due to the human factor. We were able to identify when developers were more or less focused in the essential tasks they were required to perform. Less focused teams had the more complex process models, due to the spurious / non-essential actions that were carried out. In other words, they were less efficient. Experts’ opinion confirmed that those teams also were less effective in their expected delivery. We therefore concluded that a self-awareness of the performed process rendered by our approach, may be used to identify corrective actions that will improve process efficiency (less wasted effort) and may yield to better deliverables, i.e. improved process effectiveness.info:eu-repo/semantics/acceptedVersio
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