400 research outputs found
Extremality and stationarity of collections of sets : metric, slope and normal cone characterisations
Variational analysis, a relatively new area of research in mathematics, has become one of the most powerful tools in nonsmooth optimisation and neighbouring areas. The extremal principle, a tool to substitute the conventional separation theorem in the general nonconvex environment, is a fundamental result in variational analysis. There have seen many attempts to generalise the conventional extremal principle in order to tackle certain optimisation models. Models involving collections of sets, initiated by the extremal principle, have proved their usefulness in analysis and optimisation, with non-intersection properties (or their absence) being at the core of many applications: recall the ubiquitous convex separation theorem, extremal principle, Dubovitskii Milyutin formalism and various transversality/regularity properties. We study elementary nonintersection properties of collections of sets, making the core of the conventional definitions of extremality and stationarity. In the setting of general Banach/Asplund spaces, we establish nonlinear primal (slope) and linear/nonlinear dual (generalised separation) characterisations of these non-intersection properties. We establish a series of consequences of our main results covering all known formulations of extremality/ stationarity and generalised separability properties. This research develops a universal theory, unifying all the current extensions of the extremal principle, providing new results and better understanding for the exquisite theory of variational analysis. This new study also results in direct solutions for many open questions and new future research directions in the fields of variational analysis and optimisation. Some new nonlinear characterisations of the conventional extremality/stationarity properties are obtained. For the first time, the intrinsic transversality property is characterised in primal space without involving normal cones. This characterisation brings a new perspective on intrinsic transversality. In the process, we thoroughly expose and classify all quantitative geometric and metric characterisations of transversality properties of collections of sets and regularity properties of set-valued mappings.Doctor of Philosoph
You Get What You Deserve: The Struggle for Worthiness of International Students and Workers
To attack the current immigration policies, Trump borrowed largely from the assumption that the current system is not a meritocracy, bringing in unworthy immigrants. Reflecting on the heavy influence from her mother, her journey, and experiences that led to her present life as a “legal alien” studying and working predominantly in the American higher education system, the author questioned the assumptions behind the idea of worthiness, deservingness, and responsibility. Anchored from post-colonialism theories, the authored outlined the challenges and potentials for those with similar immigration status and educational privilege
Non-contact thickness measurement using UTG
A measurement structure for determining the thickness of a specimen without mechanical contact but instead employing ultrasonic waves including an ultrasonic transducer and an ultrasonic delay line connected to the transducer by a retainer or collar. The specimen, whose thickness is to be measured, is positioned below the delay line. On the upper surface of the specimen a medium such as a drop of water is disposed which functions to couple the ultrasonic waves from the delay line to the specimen. A receiver device, which may be an ultrasonic thickness gauge, receives reflected ultrasonic waves reflected from the upper and lower surface of the specimen and determines the thickness of the specimen based on the time spacing of the reflected waves
Necessary conditions for non-intersection of collections of sets
This paper continues studies of non-intersection properties of finite collections of sets initiated 40 years ago by the extremal principle. We study elementary non-intersection properties of collections of sets, making the core of the conventional definitions of extremality and stationarity. In the setting of general Banach/Asplund spaces, we establish new primal (slope) and dual (generalized separation) necessary conditions for these non-intersection properties. The results are applied to convergence analysis of alternating projections. © 2021 Informa UK Limited, trading as Taylor & Francis Group
Necessary Conditions for Non-Intersection of Collections of Sets
This paper continues studies of non-intersection properties of finite
collections of sets initiated 40 years ago by the extremal principle. We study
elementary non-intersection properties of collections of sets, making the core
of the conventional definitions of extremality and stationarity. In the setting
of general Banach/Asplund spaces, we establish new primal (slope) and dual
(generalized separation) necessary conditions for these non-intersection
properties. The results are applied to convergence analysis of alternating
projections.Comment: 26 page
Innovation Measurement Software
Innovation is essential in our technological society. There exist a large number of innovative companies in the world, however, still there is a great scope for many others to join and take advantage of this treasure that have caused success for many organizations. There are a growing number of authors in the field of innovation, that have a mount of articles about innovation, innovation management and innovation management tools. When approaching more to the innovations assessment tools however, there is a lack of required tools for measuring innovativeness in organizations. This master thesis is based on an international data base from a survey of 221 companies in 2009. The analyzes is based on the survey which includes 95 questions, that are divided into four areas, dependent on company characteristics, innovation factors, internal and external factors. The main questions of this research is which industries/sectors are in general more innovative than others, and what are the factors influencing this? Which industries are more focused on product, process or service innovation? The relationship between companies size, revenue, profit with identifying external partners for collaborating and innovation is discussed as well. A number of innovation management tools are studied here, like learning and education to employ- ees, sharing best practises in organizations, having good metrics for evaluating the success in organization etc, with the question if these tools influence organizations and help them become a leader in innovation
Cutting Plane Algorithms are Exact for Euclidean Max-Sum Problems
This paper studies binary quadratic programs in which the objective is
defined by a Euclidean distance matrix, subject to a general polyhedral
constraint set. This class of nonconcave maximisation problems includes the
capacitated, generalised and bi-level diversity problems as special cases. We
introduce two exact cutting plane algorithms to solve this class of
optimisation problems. The new algorithms remove the need for a concave
reformulation, which is known to significantly slow down convergence. We
establish exactness of the new algorithms by examining the concavity of the
quadratic objective in a given direction, a concept we refer to as directional
concavity. Numerical results show that the algorithms outperform other exact
methods for benchmark diversity problems (capacitated, generalised and
bi-level), and can easily solve problems of up to three thousand variables
An exact cutting plane method for solving p-dispersion-sum problems
This paper aims to answer an open question recently posed in the literature,
that is to find a fast exact method for solving the p-dispersion-sum problem
(PDSP), a nonconcave quadratic binary maximization problem. We show that, since
the Euclidean distance matrix defining the quadratic term in (PDSP) is always
conditionally negative definite, the cutting plane method is exact for (PDSP)
even in the absence of concavity. As such, the cutting plane method, which is
primarily designed for concave maximisation problems, converges to the optimal
solution of the (PDSP). The numerical results show that the method outperforms
other exact methods for solving (PDSP), and can solve to optimality large
instances of up to two thousand variables
A Note on the Finite Convergence of Alternating Projections
We establish sufficient conditions for finite convergence of the alternating
projections method for two non-intersecting and potentially nonconvex sets. Our
results are based on a generalization of the concept of intrinsic
transversality, which until now has been restricted to sets with nonempty
intersection. In the special case of a polyhedron and closed half space, our
sufficient conditions define the minimum distance between the two sets that is
required for alternating projections to converge in a single iteration.Comment: 9 pages, 7 figure
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