136,304 research outputs found
Computer-Aided Conceptual Design Through TRIZ-based Manipulation of Topological Optimizations
Organised by: Cranfield UniversityIn a recent project the authors proposed the adoption of Optimization Systems [1] as a bridging element
between Computer-Aided Innovation (CAI) and PLM to identify geometrical contradictions [2], a particular
case of the TRIZ physical contradiction [3].
A further development of the research has revealed that the solutions obtained from several topological
optimizations can be considered as elementary customized modeling features for a specific design task. The
topology overcoming the arising geometrical contradiction can be obtained through a manipulation of the
density distributions constituting the conflicting pair. Already two strategies of density combination have been
identified as capable to solve geometrical contradictions.Mori Seiki â The Machine Tool Compan
Application of the inhomogeneous Lippmann-Schwinger equation to inverse scattering problems
In this paper we present a hybrid approach to numerically solve
two-dimensional electromagnetic inverse scattering problems, whereby the
unknown scatterer is hosted by a possibly inhomogeneous background. The
approach is `hybrid' in that it merges a qualitative and a quantitative method
to optimize the way of exploiting the a priori information on the background
within the inversion procedure, thus improving the quality of the
reconstruction and reducing the data amount necessary for a satisfactory
result. In the qualitative step, this a priori knowledge is utilized to
implement the linear sampling method in its near-field formulation for an
inhomogeneous background, in order to identify the region where the scatterer
is located. On the other hand, the same a priori information is also encoded in
the quantitative step by extending and applying the contrast source inversion
method to what we call the `inhomogeneous Lippmann-Schwinger equation': the
latter is a generalization of the classical Lippmann-Schwinger equation to the
case of an inhomogeneous background, and in our paper is deduced from the
differential formulation of the direct scattering problem to provide the
reconstruction algorithm with an appropriate theoretical basis. Then, the point
values of the refractive index are computed only in the region identified by
the linear sampling method at the previous step. The effectiveness of this
hybrid approach is supported by numerical simulations presented at the end of
the paper.Comment: accepted in SIAM Journal on Applied Mathematic
Hybrid actors and role tensions: How do professional-managers negotiate an identity-based compromise?
Today French public management is exposed to numerous changes, changes which are taking the shape of performance management devolution efforts within public organizations. These evolutions aim at conferring more autonomy to actors who are closer to the field, by assigning more responsibilities to them: definition of objectives, measurement of results, resource allocation... This phenomenon is currently manifesting itself inside public hospital organizations, in the same vein that Anglo-Saxon traditions are being influenced by the âNew Public Managementâ movement. In 2003, the French government launched the âHospital 2007â plan, a reform aiming, among other things, at internally âremodelingâ public hospitals, by making them change from traditional department based organizations to âpole of activityâ based organizations. This new hospital organization gave rise to the need to create new âlinksâ in the system. New roles consequently emerged in the organization, roles that we qualify as âhybridsâ because they associate both professional activities â the practice of medicine, care... â and management activities â human resource management, team organization, financial management... Therefore, these âprofessional-managersâ play a cross-disciplinary role in the organization, a role which, however, seems difficult to assume. First, the combination of professional and managerial functions seems problematic because of the divergent interests actors attribute to them â quality of care for the health care professional, cost of care for the manager. Besides, the âmixedâ hierarchical position proves to be constraining for actors, who become âstuckâ between the administrative imperatives and pole staff expectations. Our research aims at shedding light on the issue of âprofessional-managerâ role conflicts, through an identity-based approach and through the study of identity-role interactions. Pursuing this logic, we mobilize a theoretical framework focused on both role conflict literature and identity work theory. We then compare and contrast these theoretical approaches to practical elements using document analysis and interviews which we collected from a rich case study based in a large French hospital. Next, we highlight two main results. First, we argue that hybrid actors reach compromises between their personal identity and their social identity in order to limit divergent behaviors in their daily work. We also suggest that this compromise allows actors to explore new potential roles and to favor those which appear to be the most congruent with their identities. Finally, we discuss these results in our last section, by placing them in the more global context of identity and role.role hybridization; role tensions; conflicting identities; identity work theory
A Method for Geometry Optimization in a Simple Model of Two-Dimensional Heat Transfer
This investigation is motivated by the problem of optimal design of cooling
elements in modern battery systems. We consider a simple model of
two-dimensional steady-state heat conduction described by elliptic partial
differential equations and involving a one-dimensional cooling element
represented by a contour on which interface boundary conditions are specified.
The problem consists in finding an optimal shape of the cooling element which
will ensure that the solution in a given region is close (in the least squares
sense) to some prescribed target distribution. We formulate this problem as
PDE-constrained optimization and the locally optimal contour shapes are found
using a gradient-based descent algorithm in which the Sobolev shape gradients
are obtained using methods of the shape-differential calculus. The main novelty
of this work is an accurate and efficient approach to the evaluation of the
shape gradients based on a boundary-integral formulation which exploits certain
analytical properties of the solution and does not require grids adapted to the
contour. This approach is thoroughly validated and optimization results
obtained in different test problems exhibit nontrivial shapes of the computed
optimal contours.Comment: Accepted for publication in "SIAM Journal on Scientific Computing"
(31 pages, 9 figures
Self-consistent simulation of plasma scenarios for ITER using a combination of 1.5D transport codes and free-boundary equilibrium codes
Self-consistent transport simulation of ITER scenarios is a very important
tool for the exploration of the operational space and for scenario
optimisation. It also provides an assessment of the compatibility of developed
scenarios (which include fast transient events) with machine constraints, in
particular with the poloidal field (PF) coil system, heating and current drive
(H&CD), fuelling and particle and energy exhaust systems. This paper discusses
results of predictive modelling of all reference ITER scenarios and variants
using two suite of linked transport and equilibrium codes. The first suite
consisting of the 1.5D core/2D SOL code JINTRAC [1] and the free boundary
equilibrium evolution code CREATE-NL [2,3], was mainly used to simulate the
inductive D-T reference Scenario-2 with fusion gain Q=10 and its variants in H,
D and He (including ITER scenarios with reduced current and toroidal field).
The second suite of codes was used mainly for the modelling of hybrid and
steady state ITER scenarios. It combines the 1.5D core transport code CRONOS
[4] and the free boundary equilibrium evolution code DINA-CH [5].Comment: 23 pages, 18 figure
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Word shape analysis for a hybrid recognition system
This paper describes two wholistic recognizers developed for use in a hybrid recognition system. The recognizers use information about the word shape. This information is strongly related to word zoning. One of the recognizers is explicitly limited by the accuracy of the zoning information extraction. The other recognizer is designed so as to avoid this limitation. The recognizers use very simple sets of features and fuzzy set based pattern matching techniques. This not only aims to increase their robustness, but also causes problems with disambiguation of the results. A verification mechanism, using letter alternatives as compound features, is introduced. Letter alternatives are obtained from a segmentation based recognizer coexisting in the hybrid system. Despite some remaining disambiguation problems, wholistic recognizers are found capable of outperforming the segmentation based recognizer. When working together in a hybrid system, the results are significantly higher than that of the individual recognizers. Recognition results are reported and compared
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