610 research outputs found
Coupling of Josephson flux-flow oscillators to an external RC load
We investigate by numerical simulations the behavior of the power dissipated
in a resistive load capacitively coupled to a Josephson flux flow oscillator
and compare the results to those obtained for a d.c. coupled purely resistive
load. Assuming realistic values for the parameters R and C, both in the high-
and in the low-Tc case the power is large enough to allow the operation of such
a device in applications.Comment: uuencoded, gzipped tar archive containing 11 pages of REVTeX text + 4
PostScript figures. To appear in Supercond. Sci. Techno
Modeling of system knowledge for efficient agile manufacturing : tool evaluation, selection and implementation scenario in SMEs
In the manufacturing world, knowledge is fundamental in order to achieve effective and efficient real time decision making. In order to make manufacturing system knowledge available to the decision maker it has to be first captured and then modelled. Therefore tools that provide a suitable means for capturing and representation of manufacturing system knowledge are required in several types of industrial sectors and types of companyâs (large, SME). A literature review about best practice for capturing requirements for simulation development and system knowledge modeling has been conducted. The aim of this study was to select the best tool for manufacturing system knowledge modelling in an open-source environment. In order to select this tool, different criteria were selected, based on which several tools were analyzed and rated. An exemplary use case was then developed using the selected tool, Systems Modeling Language (SysML). Therefore, the best practice has been studied, evaluated, selected and then applied to two industrial use cases by the use of a selected opens source tool.peer-reviewe
Information support and interactive planning in the digital factory : approach and industry-driven evaluation
In the modern world we are continuously surrounded by information. The human brain has to analyse and interpret this information to transform into useable knowledge that is then used in decision making activities. The advent and implementation of Industry 4.0 will make it a requirement for systems within factories to interact and share large quantities of information with each other. This large volume of information will make it even more difficult for the human resources within the factory to sift through the large amount of information required since there is a limit to the information that our brains can cope with. Just in time information retrieval (JITIR) within the digital factory environment aims to provide support to the human stakeholders in the system by proactively yet non-intrusively providing the required information at the right time based on the users context. This paper will therefore provide an insight into the cognitive difficulties experienced by humans in the digital factory and how JITIR can tackle these challenges. By validating the JITIR concept, several industry scenarios have been evaluated: an exemplary model, concerning the machine tool industry, is presented in the paper. The results of this research are a set of guidelines for the development of a digital factory support tool.peer-reviewe
Environmental assessment of vegetable crops towards the water-energy-food nexus: A combination of precision agriculture and life cycle assessment
The increase in world population and the resulting demand for food, water and energy are exerting increasing pressure on soil, water resources and ecosystems. Identification of tools to minimise the related environmental impacts within the foodâenergyâwater nexus is, therefore, crucial. The purpose of the study is to carry out an analysis of the agri-food sector in order to improve the energy-environmental performance of four vegetable crops (beans, peas, sweet corn, tomato) through a combination of precision agriculture (PA) and life cycle assessment (LCA). Thus, PA strategies were identified and a full LCA was performed on actual and future scenarios for all crops in order to evaluate the benefits of a potential combination of these two tools. In the case study analysed, a life cycle approach was able to target water consumption as a key parameter for the reduced water availability of future climate scenarios and to set a multi-objective function combining also such environmental aspects to the original goal of yield maximisation. As a result, the combination of PA with the LCA perspective potentially allowed the path for an optimal trade-off of all the parameters involved and an overall reduction of the expected environmental impacts in future climate scenarios
Diffusion tensor imaging in orthostatic tremor: a tractâbased spatial statistics study
[Abstract]
Objective
The pathogenesis of orthostatic tremor (OT) is unknown. We investigated OTârelated white matter changes and their correlations with scores from a neuropsychological testing battery.
Methods
Diffusion tensor imaging measures were compared between 14 OT patients and 14 ageâ and educationâmatched healthy controls, using wholeâbrain tractâbased spatial statistics analysis. Correlations between altered diffusion metrics and cognitive performance in OT group were assessed.
Results
In all cognitive domains (attention, executive function, visuospatial ability, verbal memory, visual memory, and language), OT patientsâ cognitive performance was significantly worse than that of healthy controls. OT patients demonstrated altered diffusivity metrics not only in the posterior lobe of the cerebellum (left cerebellar lobule VI) and in its efferent cerebellar fibers (left superior cerebellar peduncle), but also in medial lemniscus bilaterally (pontine tegmentum), anterior limb of the internal capsule bilaterally, right posterior limb of the internal capsule, left anterior corona radiata, right insula, and the splenium of corpus callosum. No relationship was found between diffusion measures and disease duration in OT patients. Diffusion white matter changes, mainly those located in right anterior limb of the internal capsule, were correlated with poor performance on tests of executive function, visuospatial ability, verbal memory, and visual memory in OT patients.
Interpretation
White matter changes were preferentially located in the cerebellum, its efferent pathways, as well as in the pontine tegmentum and key components of the frontalâthalamicâcerebellar circuit. Further work needs to be done to understand the evolution of these white matter changes and their functional consequences.National Institutes of Health; R01 NS39422National Institutes of Health; R01 NS094607National Institutes of Health; R01 NS085136National Institutes of Health; R01 NS073872National Institutes of Health; R01 NS088257European Commission. Grant Number: ICTâ2011â287739Ministerio de EcnomĂa y Competitividad; RTCâ2015â3967â1Spanish Health Research Agency; FIS PI12/01602Spanish Health Research Agency; FIS PI16/00451Ministerio de EcnomĂa y Competitividad; DPIâ2015â68664âC4â1â
A data mining approach for classification of orthostatic and essential tremor based on MRIâderived brain volume and cortical thickness
[Abstract] Objective - Orthostatic tremor (OT) is an extremely rare, misdiagnosed, and underdiagnosed disorder affecting adults in midlife. There is debate as to whether it is a different condition or a variant of essential tremor (ET), or even, if both conditions coexist. Our objective was to use data mining classification methods, using magnetic resonance imaging (MRI)âderived brain volume and cortical thickness data, to identify morphometric measures that help to discriminate OT patients from those with ET. Methods - MRIâderived brain volume and cortical thickness were obtained from 14 OT patients and 15 ageâ, sexâ, and educationâmatched ET patients. Feature selection and machine learning methods were subsequently applied. Results - Four MRI features alone distinguished the two, OT from ET, with 100% diagnostic accuracy. More specifically, left thalamus proper volume (normalized by the total intracranial volume), right superior parietal volume, right superior parietal thickness, and right inferior parietal roughness (i.e., the standard deviation of cortical thickness) were shown to play a key role in OT and ET characterization. Finally, the left caudal anterior cingulate thickness and the left caudal middle frontal roughness allowed us to separate with 100% diagnostic accuracy subgroups of OT patients (primary and those with mild parkinsonian signs). Conclusions - A data mining approach applied to MRIâderived brain volume and cortical thickness data may differentiate between these two types of tremor with an accuracy of 100%. Our results suggest that OT and ET are distinct conditions.National Institutes of Health (United States); #R01, NS39422National Institutes of Health (United States), #R01, NS094607National Institutes of Health (United States); #R01, NS085136National Institutes of Health (United States); #R01, NS073872National Institutes of Health (United States); #R01, NS085136National Institutes of Health (United States); #R01, NS088257European Commission; ICTâ2011â287739Ministerio de EconomĂa y Competitividad; RTCâ2015â3967â1Agencia Española de InvestigaciĂłn de la Salud; FIS PI12/01602Agencia Española de InvestigaciĂłn de la Salud; FIS PI16/00451Madrid Robotics Digital Innovation Hub; S2018/NMTâ433
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Development of a common data model for scientific simulations
The problem of sharing data among scientific simulation models is a difficult and persistent one. Computational scientists employ an enormous variety of discrete approximations in modeling physical processes on computers. Problems occur when models based on different representations are required to exchange data with one another, or with some other software package. Within the DOE`s Accelerated Strategic Computing Initiative (ASCI), a cross-disciplinary group called the Data Models and Formats (DMF) group, has been working to develop a common data model. The current model is comprised of several layers of increasing semantic complexity. One of these layers is an abstract model based on set theory and topology called the fiber bundle kernel (FBK). This layer provides the flexibility needed to describe a wide range of mesh-approximated functions as well as other entities. This paper briefly describes the ASCI common data model, its mathematical basis, and ASCI prototype development. These prototypes include an object-oriented data management library developed at Los Alamos called the Common Data Model Library or CDMlib, the Vector Bundle API from the Lawrence Livermore Laboratory, and the DMF API from Sandia National Laboratory
AmbiĂȘncia nas instalaçÔes para produção de leite.
Este capĂtulo tem por finalidade apresentar as principais instalaçÔes de um sistema de produção de leite destinado a animais em pastagem com suplementos alimentĂcios e uso de inseminação artificial. NĂŁo serĂŁo apresentados detalhes estruturais das instalaçÔes, jĂĄ que o planejamento de construçÔes rurais deve ser feito por tĂ©cnicos especializados com base nas caracterĂsticas da propriedade e dos objetivos do produtor. No entanto, serĂŁo listadas as principais instalaçÔes para um sistema de produção de leite e serĂŁo propostas algumas estratĂ©gias para adequar a ambiĂȘncia dessas instalaçÔes, considerando o clima tropical Ășmido, que Ă© predominante na RegiĂŁo AmazĂŽnica brasileira.bitstream/item/217361/1/cpafro-18462.pd
Diffusion tensor imaging in orthostatic tremor: a tract-based spatial statistics study.
Objective: The pathogenesis of orthostatic tremor (OT) is unknown. We investigated
OT-related white matter changes and their correlations with scores from
a neuropsychological testing battery. Methods: Diffusion tensor imaging
measures were compared between 14 OT patients and 14 age- and educationmatched
healthy controls, using whole-brain tract-based spatial statistics analysis.
Correlations between altered diffusion metrics and cognitive performance in
OT group were assessed. Results: In all cognitive domains (attention, executive
function, visuospatial ability, verbal memory, visual memory, and language),
OT patientsâ cognitive performance was significantly worse than that of healthy
controls. OT patients demonstrated altered diffusivity metrics not only in the
posterior lobe of the cerebellum (left cerebellar lobule VI) and in its efferent
cerebellar fibers (left superior cerebellar peduncle), but also in medial lemniscus
bilaterally (pontine tegmentum), anterior limb of the internal capsule bilaterally,
right posterior limb of the internal capsule, left anterior corona radiata,
right insula, and the splenium of corpus callosum. No relationship was found
between diffusion measures and disease duration in OT patients. Diffusion
white matter changes, mainly those located in right anterior limb of the internal
capsule, were correlated with poor performance on tests of executive function,
visuospatial ability, verbal memory, and visual memory in OT patients. Interpretation:
White matter changes were preferentially located in the cerebellum,
its efferent pathways, as well as in the pontine tegmentum and key components
of the frontalâthalamicâcerebellar circuit. Further work needs to be done to
understand the evolution of these white matter changes and their functional
consequences.post-print404 K
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