Emulation of modular manufacturing machines using CAD modelling

Designing, testing and debugging a machine control system which controls mechatronic hardware elements can be a complex, time consuming and costly procedure. It is often extremely difficult for the system builder to envisage in advance the effects of small changes to the control system logic, with potentially dangerous results if the hardware consists of heavy machinery. It is also rare that a system builder will arrive at a working prototype on the first attempt and discovering the reasons for incorrect operation without a suitable means of comprehending the problems can be an arduous task. This paper describes an approach which supports the designing, testing and debugging of modular manufacturing machines using 3D graphical models of the machine hardware. The paper emphasises the underlying methodology of the approach, which involves collecting timing data from the executing control system under development, then emulating the operation of the machine by using this data to drive a graphical model of the hardware. The term “emulation” is used to mean modelling using data captured from the real machine as opposed to “simulation” which synthesises data. The work builds on previous research at the MSI Research Institute concerned with the control of modular machines. Two new extensions to this work are described here, which form the basis of the emulation capability. The first is the addition of the ability to execute the control system without the mechatronic hardware elements present whilst still retaining the operational behaviour of the application. The second is the mechanism for collecting the run-time data which defines these operational characteristics, to drive the machine emulation. The features of the custom 3D modeller are presented and its use for machine emulation is described. An example of a real control system under development is given to illustrate the complete process. The research objectives of the work described here are concerned with the fundamental problems designers encounter when trying to prototype the control systems of modular machines. The research has shown that the ability to execute the control system with or without the mechatronic hardware elements present can be a considerable advantage if supported by a CAD-based emulation system

Emulation of modular manufacturing machines

A method for geometrically modelling and emulating modular machines based on the Universal Machine Control reference architecture is described. Geometric modelling is achieved through extensions to a proprietary robot simulation system. A library of modules consisting of 1, 2 or 3 degree of freedom manipulators is used to construct models of multi-degree of freedom distributed machines with appropriate kinematic characteristics. Logging of data from the real or emulated control handlers is then used to drive the geometric model. A case study of a printed circuit board assembly machine is used to demonstrate how this approach allows the investigation of machine performance before and during the building of the machine with real hardware elements

High-resolution wetness index mapping: A useful tool for regional scale wetland management

Wetland ecosystems are key habitats for carbon sequestration, biodiversity and ecosystem services, yet in many they localities have been subject to modification or damage. In recent years, there has been increasing focus on effective management and, where possible, restoration of wetlands. Whilst this is highly laudable, practical implementation is limited by the high costs and unpredictable rates of success. Accordingly, there is a need for spatial information to guide restoration, ideally at the regional scale that land managers operate. In this study, we use high-resolution Light Detection and Ranging (LiDAR)-derived elevation, in conjunction with regional soil and land cover maps, to model the wetness potential of an area of conservation importance in north-west England. We use the Compound Topographic Index (CTI) as a measure for the site-specific wetness and potential to be receptive to wetland restoration. The resulting model is in agreement with the regional-scale distribution of wetlands and is clearly influenced by the topographic and soil parameters. An assessment of three representative case studies highlights the small scale features that determine the potential wetness of an area. For each site, the model results conform to the expected patterns of wetness, highlighting restoration and management activity. Furthermore, areas showing high potential wetness that may be suitable for wetland habitat creation, are highlighted. The increasing availability of LiDAR data at regional and national scales will allow studies of this nature to be undertaken at previously unobtainable resolutions. Simple models, such as implemented here, benefit from explainability and relatability and have clear potential for use by managers and conservation agencies involved in wetland restoration

On Nucleon Electromagnetic Form Factors: A Pre'cis

Electron scattering at large Q^2 probes a nucleon's quark core. This core's contribution to electromagnetic form factors may be calculated using Poincare' covariant Faddeev amplitudes combined with a nucleon-photon vertex that automatically fulfills a Ward-Takahashi identity for on-shell nucleons. The calculated behaviour of G_E^p(Q^2)/G_M^p(Q^2) on 2<Q^2(GeV^2)<6 agrees with that inferred from polarisation transfer data, and exhibits a zero at Q^2\approx 6.5 GeV^2. There is some evidence that F_2(Q^2)/F_1(Q^2) \propto [\ln(Q^2/\Lambda^2)]^2/Q^2 for Q^2>6 GeV^2.Comment: Contribution to the proceedings of "Baryons 04," the 10th International Conference on the Structure of Baryons, 25-29/Oct./04, Ecole Polytechnique, Palaiseau; 5 pages, 3 figure

Adaptation of the Rapid Estimate of Adult Litera cy in Medicine Revised (REALM -R) to the South African context: Part 1

Literacy levels are increasingly important in health care because professional nurses and other health care professionals often use written health education materials as a major component in patient education. In South Africa, no current instrument is available to assess the literacy levels of patients in the primary health care setting, though several instruments have been developed and validated internationally. The purpose of this paper was to adapt and validate the Rapid Estimate of Adult Literacy in Medicine Revised (REALM-R) to the South African context. The REALM-R is a short instrument that is designed to rapidly screen clients in the primary health care setting for low health literacy. A modified Delphi-technique was used to measure the judgement of a group of experts for the purpose of making a decision. Eight experts in the field of Nursing Science were selected purposively to obtain the most reliable consensus. Data was collected by means of a selfreport whereby participants responded to a series of questions posed by the researcher. Descriptive statistics was used for analysing data. The REALM-R was adapted to the South African context to ensure that the literacy level of South African clients is measured with an appropriate instrument. Opsomming Geletterdheidsvlakke word toenemend belangrik in gesondheidsorg aangesien geregistreerde verpleegkundiges en ander gesondheidswerkers dikwels geskrewe gesondheidopvoedkundige materiaal gebruik. Op die oomblik in Suid-Afrika is daar geen geletterdheidsvlaksinstrument beskikbaar om pasiënte in primêre gesondheidsorg se geletterdheid te toets nie. Daar bestaan wel gevalideerde internasionale instrumente. Die doel van die studie was om die REALM-R, ‘n internasionaal gevalideerde mediese geletterdheidsinstrument, aan te pas en te valideer om in die Suid-Afrikaanse konteks gebruik te kan word. Die REALM-R is ‘n kort geletterdheidsinstrument wat ontwikkel was om primêre sorg pasiênte wat moontlik lae geletterdheidsvaardigheid het, te kansif. ‘n Aangepasde Delphi-tegniek is gebruik om die oordeel van ‘n groep kundiges in te win. Agt kundiges in verpleegwetenskappe is doelgerig gekies ten einde ‘n betroubare ooreenkoms te verkry.Data is deur middel van self-raportering ingewin deurdat die deelnemers op vrae, gestel deur die navorser, geantwoord het. Beskrywende statistiek is gebruik om die data te ontleed. Die REALM-R is aangepas vir die Suid-Afrikaanse konteks ten einde ‘n geskikte instrument beskikbaar te stel om die geletterdheidsvaardigheid van primêre sorg pasiente vinnig en akkuraat te kan meet

Climatology of the harmonic frequency separation of ionospheric Alfvén Resonances at Eskdalemuir Observatory, UK

We extracted the harmonic frequency separation (Δf) of Ionospheric Alfvén Resonances (IAR) observed in the Eskdalemuir induction coil magnetometer data for the 9 year data set of 2013–2021. To obtain Δf values, we used a machine learning technique that identifies the harmonics and from this we calculated the average separation. To investigate the climatology of the IAR, we have modeled the Δf of the IAR for the data set using a time of flight calculation with model Alfvén velocity profiles. When analyzing Δf from the model and data, we found that in general they follow the same trends. The modeled Δf and Δf from the data both show an inverse correlation with foF2, which confirms that the frequencies of the IAR are controlled by electron density. It follows that Δf is greater around midnight and during the winter months, due to the decrease in plasma mass density. Variability is also reflected when comparing yearly trends in Δf with the sunspot number; higher frequencies are observed and modeled at low sunspot number. It is difficult to examine trends with instantaneous geomagnetic activity as IAR are not visible in spectrograms when geomagnetic activity is high. We find cases where the difference in measured and modeled Δf is significant, suggesting that the model does not capture short term variations in plasma mass density that influence the IAR during these days. We plan to undertake further modeling of Δf on shorter timescales

Schwinger functions and light-quark bound states, and sigma terms

We explore the viability of using solely spacelike information about a Schwinger function to extract properties of bound states. In a concrete example it is not possible to determine properties of states with masses \gsim 1.2 GeV. Modern Dyson-Schwinger equation methods supply a well-constrained tool that provide access to hadron masses and \sigma-terms. We report values of the latter for a range of hadrons. Of interest is analysis relating to a u,d scalar meson, which is compatible with a picture of the lightest 0^{++} as a bound state of a dressed-quark and -antiquark supplemented by a material pion cloud. A constituent-quark \sigma-term is defined, which affords a means for assessing the flavour-dependence of dynamical chiral symmetry breaking.Comment: To appear in the proceedings of Workshop on Light-Cone QCD and Nonperturbative Hadron Physics 2005 (LC 2005), Cairns, Queensland, Australia, 7-15 Jul 200

Grey-matter texture abnormalities and reduced hippocampal volume are distinguishing features of schizophrenia

Neurodevelopmental processes are widely believed to underlie schizophrenia. Analysis of brain texture from conventional magnetic resonance imaging (MRI) can detect disturbance in brain cytoarchitecture. We tested the hypothesis that patients with schizophrenia manifest quantitative differences in brain texture that, alongside discrete volumetric changes, may serve as an endophenotypic biomarker. Texture analysis (TA) of grey matter distribution and voxel-based morphometry (VBM) of regional brain volumes were applied to MRI scans of 27 patients with schizophrenia and 24 controls. Texture parameters (uniformity and entropy) were also used as covariates in VBM analyses to test for correspondence with regional brain volume. Linear discriminant analysis tested if texture and volumetric data predicted diagnostic group membership (schizophrenia or control). We found that uniformity and entropy of grey matter differed significantly between individuals with schizophrenia and controls at the fine spatial scale (filter width below 2 mm). Within the schizophrenia group, these texture parameters correlated with volumes of the left hippocampus, right amygdala and cerebellum. The best predictor of diagnostic group membership was the combination of fine texture heterogeneity and left hippocampal size. This study highlights the presence of distributed grey-matter abnormalities in schizophrenia, and their relation to focal structural abnormality of the hippocampus. The conjunction of these features has potential as a neuroimaging endophenotype of schizophrenia

Adjustment of the electric current in pulsar magnetospheres and origin of subpulse modulation

The subpulse modulation of pulsar radio emission goes to prove that the plasma flow in the open field line tube breaks into isolated narrow streams. I propose a model which attributes formation of streams to the process of the electric current adjustment in the magnetosphere. A mismatch between the magnetospheric current distribution and the current injected by the polar cap accelerator gives rise to reverse plasma flows in the magnetosphere. The reverse flow shields the electric field in the polar gap and thus shuts up the plasma production process. I assume that a circulating system of streams is formed such that the upward streams are produced in narrow gaps separated by downward streams. The electric drift is small in this model because the potential drop in narrow gaps is small. The gaps have to drift because by the time a downward stream reaches the star surface and shields the electric field, the corresponding gap has to shift. The transverse size of the streams is determined by the condition that the potential drop in the gaps is sufficient for the pair production. This yields the radius of the stream roughly 10% of the polar cap radius, which makes it possible to fit in the observed morphological features such as the "carousel" with 10-20 subbeams and the system of the core - two nested cone beams.Comment: 8 pages, 1 figur