494 research outputs found
The History of the Dalat Nuclear Reactor
Undergraduate Research Opportunity Program (UROP)http://deepblue.lib.umich.edu/bitstream/2027.42/116113/1/TheHistoryofthe_Dalat_Nuclear_Reactor.pd
EL LaunchPad: Creating a practical online resource for elementary teachers of English language learners from the educator perspective
The purpose of this project is to develop a practical website for elementary teachers of English learners (ELs). Initial research states ELs are the fastest growing population in k-12 education in the U.S., revealing a need for teacher access to effective materials and a community of support and collaboration. Existing websites are evaluated to assess the gap in features of these resources and how to move forward in website development. In addition, in-service elementary EL teachers are surveyed to establish teacher opinion for an online resource and influence web design and available content. Finally, based on the research phases of the project, a website for teachers that promotes a space for community connection, collaboration, and the sharing of teaching materials is designed, developed and launched: EL LaunchPad
Interval Subroutine Library Mission
We propose the collection, standardization, and distribution of a full-featured production quality library for reliable scientific computing with routines using interval techniques for use by the wide community of applications developers
Режим работы электрооборудования на тепловой станции мощностью 286 МВт
В работе представлено проектирование электрической части тепловой станции мощностью 286 МВт и анализ самозапуска электродвигателей собственных нужд.The paper presents the design of the electrical part of a thermal station with a power of 286 MW and the self-starting analysis of electric motors for auxiliary needs
Making Adaptive an Interval Constraint Propagation Algorithm Exploiting Monotonicity
International audienceA new interval constraint propagation algorithm, called MOnotonic Hull Consistency (Mohc), has recently been proposed. Mohc exploits monotonicity of functions to better filter variable domains. Embedded in an interval-based solver, Mohc shows very high performance for solving systems of numerical constraints (equations or inequalities) over the reals. However, the main drawback is that its revise procedure depends on two user-defined parameters. This paper reports a rigourous empirical study resulting in a variant of Mohc that avoids a manual tuning of the parameters. In particular, we propose a policy to adjust in an auto-adaptive way, during the search, the parameter sensitive to the monotonicity of the revised function
Latest Developments on the IEEE 1788 Effort for the Standardization of Interval Arithmetic
(Standardization effort supported by the INRIA D2T.)International audienceInterval arithmetic undergoes a standardization effort started in 2008 by the IEEE P1788 working group. The structure of the proposed standard is presented: the mathematical level is distinguished from both the implementation and representation levels. The main definitions are introduced: interval, mathematical functions, either arithmetic operations or trigonometric functions, comparison relations, set operations. While developing this standard, some topics led to hot debate. Such a hot topic is the handling of exceptions. Eventually, the system of decorations has been adopted. A decoration is a piece of information that is attached to each interval. Rules for the propagation of decorations have also been defined. Another hot topic is the mathematical model used for interval arithmetic. Historically, the model introduced by R. Moore in the 60s covered only non-empty and bounded intervals. The set-based model includes the empty set and unbounded intervals as well. Tenants of Kaucher arithmetic also insisted on offering "reverse" intervals. It has eventually been decided that an implementation must provide at least one of these flavors of interval arithmetic. The standard provides hooks for these different flavors. As the preparation of the draft should end in December 2013, no chapter is missing. However, a reference implementation would be welcome
Positive Semidefiniteness and Positive Definiteness of a Linear Parametric Interval Matrix
We consider a symmetric matrix, the entries of which depend linearly on some
parameters. The domains of the parameters are compact real intervals. We
investigate the problem of checking whether for each (or some) setting of the
parameters, the matrix is positive definite (or positive semidefinite). We
state a characterization in the form of equivalent conditions, and also propose
some computationally cheap sufficient\,/\,necessary conditions. Our results
extend the classical results on positive (semi-)definiteness of interval
matrices. They may be useful for checking convexity or non-convexity in global
optimization methods based on branch and bound framework and using interval
techniques
Impact of variations in physical parameters on glow curves for planchet heating of TL dosimeters
This study consists of a theoretical analysis of the directional planchet heating of Thermoluminescent Dosimeters (TLD) with an emphasis on influence of radiation field type, TL material properties, and heating scheme parameters on the resulting glow curve. Computer software is developed to simulate the thermal conduction and TL production processes in a planchet-heated TLD chip. The results of the simulation are benchmarked to previous experimental findings for a LiF TLD and excellent agreement is obtained. The system thermophysical parameters and initial depth-dose distribution in the TLD are varied and the position of the main glow peak and integral glow are examined. A demonstration is given of how a set of thermophysical parameters may provide information about the depth-dose distribution in the TLD and how variation in the values of these parameters may limit the reconstruction of this depth-dose information.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31122/1/0000018.pd
Branch-and-lift algorithm for deterministic global optimization in nonlinear optimal control
This paper presents a branch-and-lift algorithm for solving optimal control problems with smooth nonlinear dynamics and potentially nonconvex objective and constraint functionals to guaranteed global optimality. This algorithm features a direct sequential method and builds upon a generic, spatial branch-and-bound algorithm. A new operation, called lifting, is introduced, which refines the control parameterization via a Gram-Schmidt orthogonalization process, while simultaneously eliminating control subregions that are either infeasible or that provably cannot contain any global optima. Conditions are given under which the image of the control parameterization error in the state space contracts exponentially as the parameterization order is increased, thereby making the lifting operation efficient. A computational technique based on ellipsoidal calculus is also developed that satisfies these conditions. The practical applicability of branch-and-lift is illustrated in a numerical example. © 2013 Springer Science+Business Media New York
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