657 research outputs found
A survey on C 1,1 fuctions: theory, numerical methods and applications
In this paper we survey some notions of generalized derivative for C 1,1 functions. Furthermore some optimality conditions and numerical methods for nonlinear minimization problems involving C1,1 data are studied.
Mean value theorem for continuous vector functions by smooth approximations
In this note a mean value theorem for continuous vector functions is introduced by mollified derivatives and smooth approximations
C 1,1 functions and optimality conditions
In this work we provide a characterization of C 1,1 functions on Rn (that is, differentiable with locally Lipschitz partial derivatives) by means of second directional divided differences. In particular, we prove that the class of C 1,1 functions is equivalent to the class of functions with bounded second directional divided differences. From this result we deduce a Taylor's formula for this class of functions and some optimality conditions. The characterizations and the optimality conditions proved by Riemann derivatives can be useful to write minimization algorithms; in fact, only the values of the function are required to compute second order conditions.divided differences, Riemann derivatives, C 1,1 functions, nonlinear optimization, generalized derivatives
Fractals and Self-Similarity in Economics: the Case of a Stochastic Two-Sector Growth Model
We study a stochastic, discrete-time, two-sector optimal growth model in which the production of the homogeneous consumption good uses a Cobb-Douglas technology, combining physical capital and an endogenously determined share of human capital. Education is intensive in human capital as in Lucas (1988), but the marginal returns of the share of human capital employed in education are decreasing, as suggested by Rebelo (1991). Assuming that the exogenous shocks are i.i.d. and affect both physical and human capital, we build specific configurations for the primitives of the model so that the optimal dynamics for the state variables can be converted, through an appropriate log-transformation, into an Iterated Function System converging to an invariant distribution supported on a generalized Sierpinski gasket.fractals, iterated function system, self-similarity, Sierpinski gasket, stochastic growth
Second-order mollified derivatives and optimization
The class of strongly semicontinuous functions is considered. For these functions the notion of mollified derivatives, introduced by Ermoliev, Norkin and Wets, is extended to the second order. By means of a generalized Taylor's formula, second order necessary and sufficient conditions are proved for both unconstrained and constrained optimizationMollifiers, optimization, smooth approximations, strong semicontinuity
On the Presence of Green and Sustainable Software Engineering in Higher Education Curricula
Nowadays, software is pervasive in our everyday lives. Its sustainability and
environmental impact have become major factors to be considered in the
development of software systems. Millennials-the newer generation of university
students-are particularly keen to learn about and contribute to a more
sustainable and green society. The need for training on green and sustainable
topics in software engineering has been reflected in a number of recent
studies. The goal of this paper is to get a first understanding of what is the
current state of teaching sustainability in the software engineering community,
what are the motivations behind the current state of teaching, and what can be
done to improve it. To this end, we report the findings from a targeted survey
of 33 academics on the presence of green and sustainable software engineering
in higher education. The major findings from the collected data suggest that
sustainability is under-represented in the curricula, while the current focus
of teaching is on energy efficiency delivered through a fact-based approach.
The reasons vary from lack of awareness, teaching material and suitable
technologies, to the high effort required to teach sustainability. Finally, we
provide recommendations for educators willing to teach sustainability in
software engineering that can help to suit millennial students needs.Comment: The paper will be presented at the 1st International Workshop on
Software Engineering Curricula for Millennials (SECM2017
MINKOWSKI-ADDITIVE MULTIMEASURES, MONOTONICITY AND SELF-SIMILARITY
We discuss the main properties of positive multimeasures and we show how to define a notion of self-similarity based on a generalized Markov operator
A note on demographic shocks in a multi-sector growth model
We introduce demographic shocks in a multi-sector endogenous growth model, a-la Uzawa-Lucas. We show that an analytical solution of the stochastic problem can be found, under the restriction that the capital share equals both the inverse of the intertemporal elasticity of substitution and the degree of altruism. We show that uncertainty lowers the optimal levels of consumption and the physical capital stock, while they do not affect the share of human capital employed in production
Group-galaxy correlations in redshift space as a probe of the growth of structure
We investigate the use of the cross-correlation between galaxies and galaxy
groups to measure redshift-space distortions (RSD) and thus probe the growth
rate of cosmological structure. This is compared to the classical approach
based on using galaxy auto-correlation. We make use of realistic simulated
galaxy catalogues that have been constructed by populating simulated dark
matter haloes with galaxies through halo occupation prescriptions. We adapt the
classical RSD dispersion model to the case of the group-galaxy
cross-correlation function and estimate the RSD parameter by fitting
both the full anisotropic correlation function and its multipole
moments. In addition, we define a modified version of the latter statistics by
truncating the multipole moments to exclude strongly non-linear distortions at
small transverse scales. We fit these three observable quantities in our set of
simulated galaxy catalogues and estimate statistical and systematic errors on
for the case of galaxy-galaxy, group-group, and group-galaxy
correlation functions. When ignoring off-diagonal elements of the covariance
matrix in the fitting, the truncated multipole moments of the group-galaxy
cross-correlation function provide the most accurate estimate, with systematic
errors below 3% when fitting transverse scales larger than . Including
the full data covariance enlarges statistical errors but keep unchanged the
level of systematic error. Although statistical errors are generally larger for
groups, the use of group-galaxy cross-correlation can potentially allow the
reduction of systematics while using simple linear or dispersion models.Comment: 18 pages, 16 figure
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