Parameter identification for an abstract Cauchy problem by quasilinearization

A parameter identification problem is considered in the context of a linear abstract Cauchy problem with a parameter-dependent evolution operator. Conditions are investigated under which the gradient of the state with respect to a parameter possesses smoothness properties which lead to local convergence of an estimation algorithm based on quasi-linearization. Numerical results are presented concerning estimation of unknown parameters in delay-differential equations

Results on Transversal and Axial Motions of a System of Two Beams Coupled to a Joint through Two Legs

In recent years there has been renewed interest in inflatable-rigidizable space structures because of the efficiency they offer in packaging during boost-to-orbit. However, much research is still needed to better understand dynamic response characteristics, including inherent damping, of truss structures fabricated with these advanced material systems. We present results of an ongoing research related to a model consisting of an assembly of two beams with Kelvin-Voight damping, coupled to a simple joint through two legs. The beams are clamped at one end but at the other end they satisfy a boundary condition given in terms of an ODE coupling boundary terms of both beams, which reflects geometric compatibility conditions. The system is then written as a second order differential equation in an appropriate Hilbert space  in which well-posedness, exponential stability as well as other regularity properties of the solutions can be obtained. Two different finite dimensional approximation schemes for the solutions of the system are presented. Numerical results are presented and comparisons are made.Fil: Burns, J. A.. Interdisciplinary Center for Applied Mathematics; Estados UnidosFil: Cliff, E. M.. Interdisciplinary Center for Applied Mathematics; Estados UnidosFil: Liu, Z.. University of Minnesota at Duluth; Estados UnidosFil: Spies, Ruben Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Matemática Aplicada del Litoral. Universidad Nacional del Litoral. Instituto de Matemática Aplicada del Litoral; Argentin

An on-board near-optimal climb-dash energy management

On-board real time flight control is studied in order to develop algorithms which are simple enough to be used in practice, for a variety of missions involving three dimensional flight. The intercept mission in symmetric flight is emphasized. Extensive computation is required on the ground prior to the mission but the ensuing on-board exploitation is extremely simple. The scheme takes advantage of the boundary layer structure common in singular perturbations, arising with the multiple time scales appropriate to aircraft dynamics. Energy modelling of aircraft is used as the starting point for the analysis. In the symmetric case, a nominal path is generated which fairs into the dash or cruise state. Feedback coefficients are found as functions of the remaining energy to go (dash energy less current energy) along the nominal path

Optimal symmetric flight with an intermediate vehicle model

Optimal flight in the vertical plane with a vehicle model intermediate in complexity between the point-mass and energy models is studied. Flight-path angle takes on the role of a control variable. Range-open problems feature subarcs of vertical flight and singular subarcs. The class of altitude-speed-range-time optimization problems with fuel expenditure unspecified is investigated and some interesting phenomena uncovered. The maximum-lift-to-drag glide appears as part of the family, final-time-open, with appropriate initial and terminal transient exceeding level-flight drag, some members exhibiting oscillations. Oscillatory paths generally fail the Jacobi test for durations exceeding a period and furnish a minimum only for short-duration problems

Climb-dash real-time calculations

On-board rear-optimal climb-dash energy management, optimal symmetric flight with an intermediate vehicle model, and energy states are presented

Optimal symmetric flight studies

Several topics in optimal symmetric flight of airbreathing vehicles are examined. In one study, an approximation scheme designed for onboard real-time energy management of climb-dash is developed and calculations for a high-performance aircraft presented. In another, a vehicle model intermediate in complexity between energy and point-mass models is explored and some quirks in optimal flight characteristics peculiar to the model uncovered. In yet another study, energy-modelling procedures are re-examined with a view to stretching the range of validity of zeroth-order approximation by special choice of state variables. In a final study, time-fuel tradeoffs in cruise-dash are examined for the consequences of nonconvexities appearing in the classical steady cruise-dash model. Two appendices provide retrospective looks at two early publications on energy modelling and related optimal control theory

Health Savings Account - Eligible High Deductible Health Plans: Updating the Definition of Prevention

High-deductible health plans (HDHPs) are an important and growing part of the health insurance landscape. By some estimates, as many as 80 percent of large employers may offer an HDHP in 2014. In 2013, more than 15 million Americans received health coverage through an HDHP, a more than a threefold increase since 2007.As outlined by the U.S. Treasury Department, individuals with an HSA-eligible HDHP are required to pay the full cost of most medications and services -- in theory utilizing pre-tax HSA funds -- until deductibles are met. However, the 2003 authorizing legislation and further guidance include a safe harbor allowing plans to cover primary preventive services, those typically deemed to prevent the onset of disease, before the deductible is satisfied.Services or benefits meant to treat "an existing illness, injury or condition," are excluded from first-dollar coverage in HSA-eligible HDHPs, which encompasses most secondary preventive services. For example, plans are prohibited from providing first dollar coverage of disease management services such as insulin, eye and foot exams, and glucose monitoring supplies for patients with diabetes.As chronic disease conditions currently make up 75 percent of total U.S. health spending, appropriate chronic disease management is an important tool to lower long-term health care costs. As the market for HDHPs grow, it is important that they maintain the flexibility to allow for effective health management of all beneficiaries. This report addresses the strict definition of prevention that an HDHP must follow for it to include a pre-tax health savings account (HSA), and how this restriction limits the effectiveness of current plans. A potential solution - allowing HSA-eligible HDHPs to provide first-dollar coverage for targeted, evidence-based, secondary preventive services that prevent chronic disease progression and related complications - can improve patient-centered outcomes, add efficiency to medical spending, and enhance HDHP attractiveness.A multi-disciplinary research team from the University of Michigan's Center for Value-Based Insurance Design, Harvard Medical School, and the University of Minnesota conducted a multi-part project to investigate the impact of updatingthe definition of prevention for HDHPs to include selected secondary preventive services that are frequently used as health plan quality metrics and included as elements of pay-for-performance programs. Specifically, the project aimed to: 1) determine the premium effect, actuarial value, and estimated market uptake of the novel HDHP plan that covers these evidence-based services outside the deductible, and 2) explore through interviews whether insurance industry experts found coverage of secondary preventive services a worthwhile endeavor

Insights into subduction zone sulfur recycling from isotopic analysis of eclogite-hosted sulfides

Subduction of sulfur in ocean crust makes a significant but poorly understood contribution to the global sulfur cycle. Part of the uncertainty arises from a lack of knowledge about the metamorphic changes that affect subducted sulfur-bearing minerals, and the ultimate source of sulfur that is subducted to depth. Sulfur δ34S varies both as a function of the original sulfur source, and as a consequence of processes subsequent to sulfide crystallisation such as devolatilisation, redox reactions, and fluid loss. To investigate sulfur liberation during subduction, secondary ion mass spectroscopy (SIMS) was used to measure δ34S in grains of pyrite, chalcopyrite and pyrrhotite in eclogites from the Zermatt–Saas zone in the Western Alps, and the Pouébo terrane of New Caledonia. Trace element mapping on selected sulfide grains was also performed. Sulfides in these rocks are generally associated with greenschist retrogression assemblages, but also occur as inclusions in garnet, associated with glaucophane and omphacite, and as polysulfide grains with typicalmagmaticcombinations of minerals. δ34S varies significantly within individual pyrite grains, with striking correlations, insome cases, between Co zoning and changes in δ34SVCDT. δ34SVCDT is, in many cases, greater than 13‰, consistent with derivation from seawater-derived sulfate. The dataset suggests that sulfur isotopes in pyrite experienced little or no post-crystallisation re-equilibration, that pyrite grew under open system conditions with heterogeneous fluid flow on a thin section scale, and that sulfide growth involved sulfur addition. Prograde subduction processes most likely involved sulfur loss. Sulfide growth occurred in some samples at the very earliest stages of exhumation. Therefore these sulfides provide useful information on the fluids present in slabs at great depths

Wind measurement system

A system for remotely measuring vertical and horizontal winds present in discrete volumes of air at selected locations above the ground is described. A laser beam is optically focused in range by a telescope, and the output beam is conically scanned at an angle about a vertical axis. The backscatter, or reflected light, from the ambient particulates in a volume of air, the focal volume, is detected for shifts in wavelength, and from these, horizontal and vertical wind components are computed

Prediction and measurement of radiation damage to CMOS devices on board spacecraft

The CMOS Radiation Effects Measurement (CREM) experiment is presently being flown on the Explorer-55. The purpose of the experiment is to evaluate device performance in the actual space radiation environment and to correlate the respective measurements to on-the-ground laboratory irradiation results. The experiment contains an assembly of C-MOS and P-MOS devices shielded in front by flat slabs of aluminum and by a practically infinite shield in the back. Predictions of radiation damage to C-MOS devices are based on standard environment models and computational techniques. A comparison of the shifts in CMOS threshold potentials, that is, those measured in space to those obtained from the on-the-ground simulation experiment with Co-60, indicates that the measured space damage is smaller than predicted by about a factor of 2-3 for thin shields, but agrees well with predictions for thicker shields