Optimised electromagnetic 3d field solver for frequencies below the first resonance

An optimised low-frequency solution algorithm is proposed that reduces the electromagnetic wave equation to a small number of scalar potential problems. The latter can be solved using black-box algebraic multigrid solvers. Within the framework of the finite integration technique, the reduction of the wave equation is accomplished by tree/cotree decompositions of primary and dual grids, which allow for highly efficient solutions of Ampere's and Faraday's equations. The example of a ferrite-loaded accelerator component demonstrates that the scheme is much more efficient than the direct approach using Krylov subspace solvers     

Smart cars, smart highways

Advanced electronics is being used to unclog the transportation network and allow private vehicles, trucks, buses and trains to move further faster. already a range of technologies and ideas have been explored, deployed, and tested as part of the Intelligent Vehicle Highway System programs in the United States and Japan, and in the Road Transport Informatics program in Europe. The authors describe how these latest electronics for automobiles and roadways herald far fewer traffic jams, greater safety, and perhaps even a decline in pollution     

Study of chemical modifications and fungi degradation of thermally modified wood using DRIFT spectroscopy

A mild thermal treatment of wood leads to improved macroscopic properties (dimensional stabilization and resistance against fungal degradation). The chemical modifications induced by the thermal treatment were investigated by means of DRIFT spectroscopy on wood blocks in order to explain the new macroscopic properties on a molecular level. The formation of new ether linkage was observed in addition to the well-known acidic hydrolysis reactions of wood. Fungal attack was found to take place even after thermal degradation of pentosanes by a standard oxidative way. A competition between depolymerization and condensation reactions was observed.     

Hybrid finite-element method for discretising cylindrically symmetric parts in electrotechnical models

In many technical devices such as transformers and electrical machines, large differences in geometric dimensions are observed. As a consequence, the generation of a 3D computational grid for the whole device leads to unacceptably large numbers of elements or can even fail. In addition to the commonly applied cartesian or cylindrical symmetries of the overall geometry, the model can be subdivided into parts featuring translational or cylindrical symmetries. Such parts are discretised separately, accounting for the local symmetry, and are then combined with the surrounding 3D model. Excitations and boundary conditions of the submodels are not necessarily symmetric but are expected to be smooth in the direction of the symmetry. Then, the field distribution at the interface is well approximated by a set of spectral elements along the dimension of symmetry. Coupling between the model parts is carried out by means of Lagrange multipliers. A single-phase transformer with thin insulation sheets is taken as an example to illustrate the proposed hybrid discretisation. The cross-section of the cylindrically symmetric part containing thin sheets, is represented by a fine 2D finite-element mesh so that all the geometrical details can be resolved, and the rest of the structure is discretised by a 3D mesh. Nevertheless, a fully 3D field distribution is calculated in all model parts. Only a small number of harmonic functions is needed to account for the azimuthal field variation at the cylindrical interface. Hence, the number of unknowns in the numerical model is reduced significantly, while a high level of accuracy is maintained     

Presence of pressure ulcer prevention methods used among patients considered at risk versus those considered not at risk

PURPOSE: This study examined pressure ulcer-prevention strategies available for patients considered at risk versus those considered not at risk. DESIGN: The study used a prospective, longitudinal design. SETTING AND SUBJECTS: Six hundred ninety-four patients from units of five acute care hospitals, a rehabilitation facility, and two nurses' home care caseloads participated in the investigation. INSTRUMENTS: Data-collection instruments included the Braden Scale for risk assessment, demographic information, and the Pressure Ulcer-Prevention Strategies tool, which assessed for the presence of 16 pressure ulcer-prevention strategies. METHODS: All patients admitted to a participating unit during a 2-month period were followed up until discharge. Depending on the site, patients were assessed for the presence of pressure ulcer-prevention strategies one to three times per week. RESULTS: Patients in the at-risk group versus those in the not-at-risk group were more likely (p < 0.01) to have the head of the bed in a low position, a pressure-reducing bed surface, pressure ulcer prevention charted, a positioning wedge, incontinence cleanser and ointment, heel protection, a prevention care plan, a trapeze, and a posted turning schedule. The at-risk group had significantly (p < 0.01) more prevention strategies present than did the not-at-risk group. However, the percentage of patients placed on a pressure ulcer-prevention program was low for both groups. CONCLUSIONS: Pressure ulcer prevention was evident for the at-risk group, but at a low rate. Institutions must continue to explore this critical area affecting patient outcomes.     

Free radicals from X-irradiated ''dry'' and hydrated lyophilized DNA as studied by electron spin resonance spectroscopy: analysis of spectral components between 77K and room temperature

In order to identify cytochemical traits relevant to understanding excitatory neurotransmission in brainstem auditory nuclei, we have analyzed in the dorsal cochlear nucleus the synaptic distribution of aspartate aminotransferase, glutamate, and vesicular zinc, three molecules probably involved in different steps of excitatory glutamatergic signaling. High levels of glutamate immunolabeling were found in three classes of synaptic endings in the dorsal cochlear nucleus, as determined by quantitation of immunogold labeling. The first type included auditory nerve endings, the second were granule cell endings in the molecular layer, and the third very large endings, better described as "mossy." This finding points to a neurotransmitter role for glutamate in at least three synaptic populations in the dorsal cochlear nucleus. The same three types of endings enriched in glutamate immunoreactivity also contained histochemically detectable levels of aspartate aminotransferase activity, suggesting that this enzyme may be involved in the synaptic handling of glutamate in excitatory endings in the dorsal cochlear nucleus. There was also extrasynaptic localization of the enzyme. Zinc ions were localized exclusively in granule cell endings, as determined by a Danscher-selenite method, suggesting that this ion is involved in the operation of granule cell synapses in the dorsal cochlear nucleus.     

Finite-time behavior of inner systems

In this paper, we investigate how nonminimum phase characteristics of a dynamical system affect its controllability and tracking properties. For the class of linear time-invariant dynamical systems, these characteristics are determined by transmission zeros of the inner factor of the system transfer function. The relation between nonminimum phase zeros and Hankel singular values of inner systems is studied and it is shown how the singular value structure of a suitably defined operator provides relevant insight about system invertibility and achievable tracking performance. The results are used to solve various tracking problems both on finite as well as on infinite time horizons. A typical receding horizon control scheme is considered and new conditions are derived to guarantee stabilizability of a receding horizon controller.     

Cognitive engineering of a new telephone operator workstation using COGNET

Many cognitive engineering methodologies for user-centered design involve modeling procedural knowledge; others deal with domain semantics or conceptual models. COGnitive NEwork of Tasks (COGNET) is a framework for modeling human cognition and decision-making which provides an integrated representation of the knowledge, behavioral actions, strategies and problem solving skills used in a domain or task situation, yielding a powerful cognitive engineering tool. A case study of the design of the user interface for a new telephone operator workstation is presented to illustrate the derivation of the design from the components of the COGNET model. The model does not directly convey any specific feature of the interface design, but rather a formal representation of what the user must do with the resulting interface. This information is then evolved through a set of transformations which systematically move toward design features, in a fully traceable manner.

Relevance to industry

With the increasing prevalence of technical systems in complex work domains, cognitive engineering is necessary in designing the user interface for those systems to promote efficient integration of person and machine. The cognitive engineering methodology presented here addresses that need.     

Designing to Facilitate Browsing: A Look Back at the Hyperties Workstation Browser

Since browsing hypertext can present a formidable cognitive challenge, user interface design plays a major role in determining acceptability. In the Unix workstation version of Hyperties, a research-oriented prototype, we focussed on design features that facilitate browsing. We first give a general overview of Hyperties and its markup language. Customizable documents can be generated by the conditional text feature that enables dynamic and selective display of text and graphics. In addition we present: — an innovative solution to link identification: pop-out graphical buttons of arbitrary shape.

— application of pie menus to permit low cognitive load actions that reduce the distraction of common actions, such as page turning or window selection.

— multiple window selection strategies that reduce clutter and housekeeping effort. We preferred piles-of-tiles, in which standard-sized windows were arranged in a consistent pattern on the display and actions could be done rapidly, allowing users to concentrate on the contents.