Spatially-Constant Material Removal Control Under Variable-Speed Robotic Sanding

2020 ◽  
Author(s):  
Cameron Devine ◽  
Joseph Garbini ◽  
Santosh Devasia
Keyword(s):  
Contact Force ◽  
Material Removal ◽  
Process Model ◽  
Surface Condition ◽  
A Priori ◽  
Variable Speed ◽  
Limited Effectiveness ◽  
Skilled Operator ◽  
Repetitive Stress ◽  
The Individual

Abstract During manufacturing, minor flaws in the surface of commercial airplane interior panels are often corrected using hand sanding, sometimes leading to repetitive stress injuries. Robotic sanding is an attractive option to mitigate these injuries. However, in preprogrammed automated sanding, both the sander path and the speed along that path are predetermined. Such fixed automation has limited effectiveness due to the part-to-part variability of surface condition. In addition, in typical fixed automation, a constant contact force and path speed are used to maintain constant material removal depth. Teleoperated robotic sanding allows a skilled operator to monitor the process and the condition of the surface in real time to correct the individual flaws. However, during teleoperated sanding, the path and speed along the path are inherently both time-varying and unknown a priori. The principal contribution of this work is to facilitate precision teleoperated sanding by developing a process model and control strategy that ensures constant material removal depth along the sanding path. Experimental results, with and without the proposed contact-force adjustments, for the same variable speed motion of the sander, shows 65% improvement in spatial variation of material removal with the proposed approach.

scholarly journals Communities and the individual: Beyond the liberal–communitarian divide

2021 ◽  
Vol 47 (4) ◽  
pp. 392-401
Author(s):  
Volker Kaul
Keyword(s):  
Personal Autonomy ◽  
A Priori ◽  
Significant Others ◽  
The Self ◽  
Global Perspective ◽  
Self And Identity ◽  
Default Position ◽  
The Individual

Liberalism believes that individuals are endowed a priori with reason or at least agency and it is up to that reason and agency to make choices, commitments and so on. Communitarianism criticizes liberalism’s explicit and deliberate neglect of the self and insists that we attain a self and identity only through the effective recognition of significant others. However, personal autonomy does not seem to be a default position, neither reason nor community is going to provide it inevitably. Therefore, it is so important to go beyond the liberal–communitarian divide. This article is analysing various proposals in this direction, asks about the place of communities and the individual in times of populism and the pandemic and provides a global perspective on the liberal–communitarian debate.

scholarly journals Statistical Uncertainty of DNS in Geometries without Homogeneous Directions

2021 ◽  
Vol 11 (4) ◽  
pp. 1399
Author(s):  
Jure Oder ◽  
Cédric Flageul ◽  
Iztok Tiselj
Keyword(s):  
Channel Flow ◽  
A Priori ◽  
Time Integration ◽  
Navier Stokes ◽  
Statistical Uncertainty ◽  
Time Step ◽  
Order Of Magnitude ◽  
Averaging Time ◽  
The Individual ◽  
Time Required

In this paper, we present uncertainties of statistical quantities of direct numerical simulations (DNS) with small numerical errors. The uncertainties are analysed for channel flow and a flow separation case in a confined backward facing step (BFS) geometry. The infinite channel flow case has two homogeneous directions and this is usually exploited to speed-up the convergence of the results. As we show, such a procedure reduces statistical uncertainties of the results by up to an order of magnitude. This effect is strongest in the near wall regions. In the case of flow over a confined BFS, there are no such directions and thus very long integration times are required. The individual statistical quantities converge with the square root of time integration so, in order to improve the uncertainty by a factor of two, the simulation has to be prolonged by a factor of four. We provide an estimator that can be used to evaluate a priori the DNS relative statistical uncertainties from results obtained with a Reynolds Averaged Navier Stokes simulation. In the DNS, the estimator can be used to predict the averaging time and with it the simulation time required to achieve a certain relative statistical uncertainty of results. For accurate evaluation of averages and their uncertainties, it is not required to use every time step of the DNS. We observe that statistical uncertainty of the results is uninfluenced by reducing the number of samples to the point where the period between two consecutive samples measured in Courant–Friedrichss–Levy (CFL) condition units is below one. Nevertheless, crossing this limit, the estimates of uncertainties start to exhibit significant growth.

scholarly journals Sartres Lösung zur Antinomie der sozialen Realität in der Kritik der dialektischen Vernunft

2020 ◽  
Vol 68 (6) ◽  
pp. 817-847
Author(s):  
Sebastian Gardner
Keyword(s):  
Ethical Theory ◽  
A Priori ◽  
Social Ontology ◽  
Human Freedom ◽  
Philosophical Foundation ◽  
A Posteriori ◽  
Political Reality ◽  
Dialectical Reason ◽  
The Individual

AbstractCritics have standardly regarded Sartre’s Critique of Dialectical Reason as an abortive attempt to overcome the subjectivist individualism of his early philosophy, motivated by a recognition that Being and Nothingness lacks ethical and political significance, but derailed by Sartre’s Marxism. In this paper I offer an interpretation of the Critique which, if correct, shows it to offer a coherent and highly original account of social and political reality, which merits attention both in its own right and as a reconstruction of the philosophical foundation of Marxism. The key to Sartre’s theory of collective and historical existence in the Critique is a thesis carried over from Being and Nothingness: intersubjectivity on Sartre’s account is inherently aporetic, and social ontology reproduces in magnified form its limited intelligibility, lack of transparency, and necessary frustration of the demands of freedom. Sartre’s further conjecture – which can be formulated a priori but requires a posteriori verification – is that man’s collective historical existence may be understood as the means by which the antinomy within human freedom, insoluble at the level of the individual, is finally overcome. The Critique provides therefore the ethical theory promised in Being and Nothingness.

scholarly journals Predicting the duration of sickness absence spells due to back pain: a population-based study from Sweden

2019 ◽  
Vol 77 (2) ◽  
pp. 115-121
Author(s):  
Annina Ropponen ◽  
Katalin Gémes ◽  
Paolo Frumento ◽  
Gino Almondo ◽  
Matteo Bottai ◽  
...  
Keyword(s):  
Back Pain ◽  
Sickness Absence ◽  
A Priori ◽  
Population Based ◽  
Final Model ◽  
Individual Level ◽  
Discriminatory Accuracy ◽  
C Statistic ◽  
International Statistical Classification ◽  
The Individual

ObjectivesWe aimed to develop and validate a prediction model for the duration of sickness absence (SA) spells due to back pain (International Statistical Classification of Diseases and Related Health Problems 10th Revision: M54), using Swedish nationwide register microdata.MethodsInformation on all new SA spells >14 days from 1 January 2010 to 30 June 2012 and on possible predictors were obtained. The duration of SA was predicted by using piecewise constant hazard models. Nine predictors were selected for the final model based on a priori decision and log-likelihood loss. The final model was estimated in a random sample of 70% of the SA spells and later validated in the remaining 30%.ResultsOverall, 64 048 SA spells due to back pain were identified during the 2.5 years; 74% lasted ≤90 days, and 9% >365 days. The predictors included in the final model were age, sex, geographical region, employment status, multimorbidity, SA extent at the start of the spell, initiation of SA spell in primary healthcare and number of SA days and specialised outpatient healthcare visits from the preceding year. The overall c-statistic (0.547, 95% CI 0.542 to 0.552) suggested a low discriminatory capacity at the individual level. The c-statistic was 0.643 (95% CI 0.634 to 0.652) to predict >90 days spells, 0.686 (95% CI 0.676 to 0.697) to predict >180 spells and 0.753 (95% CI 0.740 to 0.766) to predict >365 days spells.ConclusionsThe model discriminates SA spells >365 days from shorter SA spells with good discriminatory accuracy.

scholarly journals A MODEL OF MANAGING THE URBAN MOBILITY PLANNING PROCESS / MODEL UPRAVLJANJA PROCESOM PLANIRANJA URBANE MOBILNOSTI

2019 ◽  
Vol 16 (2) ◽  
Author(s):  
Mustafa Mehanović ◽  
Nermin Palić
Keyword(s):  
Process Model ◽  
Planning Process ◽  
Supply And Demand ◽  
Urban Mobility ◽  
Research Results ◽  
Traffic System ◽  
Development Plans ◽  
Sustainable Urban Mobility ◽  
The Individual ◽  
The City

The subject of research in this paper is the planning of urban mobility development in the narrow part of Sarajevo using a model based on the growth matrix. The hypothesis of this research is: Based on the analysis of supply and demand of the city traffic system, good practices in sustainable urban mobility and existing strategies and development plans, a model for managing the whole planning process of sustainable urban mobility of the city traffic system in Sarajevo by 2026 can be proposed.In accordance with the experience of Europe’s main urban mobility observatory (Eltis) and sustainable urban mobility plans (SUMPs), the key elements are defined. The next step, after defining the elements of urban mobility, is to carry out the quantification of elements for 2016. Thereafter, there is a concise explanation of the growth matrix and model of managing the urban mobility planning process is created. In the research results, direct and indirect growth rates were elaborated and analyzed, i.e. the individual and synergic effects of the model. Finally, the synthesis of the research results was presented.

scholarly journals Data Model and Software Architecture for Business Process Model Generator

2018 ◽  
Vol 2 (4-2) ◽  
pp. 349
Author(s):  
Ivaylo Kamenarov ◽  
Katalina Grigorova
Keyword(s):  
Software Architecture ◽  
Business Process ◽  
Data Model ◽  
Process Model ◽  
Process Models ◽  
Process Chain ◽  
Business Process Models ◽  
Model Generator ◽  
The Individual ◽  
Natural Way

This paper describes the internal data model for a business process generator. Business process models are stored in an Event-driven process chain notation that provides a natural way to link the individual elements of a process. There is a software architecture that makes it easy to communicate with users as well as external systems.

scholarly journals A qualitative analysis of the Wikipedia N-Substate Algorithm's Enhancement Terms

2019 ◽  
Vol 3 (1) ◽  
pp. 67
Author(s):  
Kyle Goslin ◽  
Markus Hofmann
Keyword(s):  
Qualitative Analysis ◽  
A Priori ◽  
Sole Source ◽  
Human Interaction ◽  
A Priori Knowledge ◽  
Search Query ◽  
Analysis Process ◽  
Automatic Search ◽  
The Individual ◽  
Priori Knowledge

<p>Automatic Search Query Enhancement (ASQE) is the process of modifying a user submitted search query and identifying terms that can be added or removed to enhance the relevance of documents retrieved from a search engine. ASQE differs from other enhancement approaches as no human interaction is required. ASQE algorithms typically rely on a source of a priori knowledge to aid the process of identifying relevant enhancement terms. This paper describes the results of a qualitative analysis of the enhancement terms generated by the Wikipedia NSubstate Algorithm (WNSSA) for ASQE. The WNSSA utilises Wikipedia as the sole source of a priori knowledge during the query enhancement process. As each Wikipedia article typically represents a single topic, during the enhancement process of the WNSSA, a mapping is performed between the user’s original search query and Wikipedia articles relevant to the query. If this mapping is performed correctly, a collection of potentially relevant terms and acronyms are accessible for ASQE. This paper reviews the results of a qualitative analysis process performed for the individual enhancement term generated for each of the 50 test topics from the TREC-9 Web Topic collection. The contributions of this paper include: (a) a qualitative analysis of generated WNSSA search query enhancement terms and (b) an analysis of the concepts represented in the TREC-9 Web Topics, detailing interpretation issues during query-to-Wikipedia article mapping performed by the WNSSA.</p>

Modeling Evolution of Microstructures Beneath Topographically Textured Surfaces Produced Using Shear Based Material Removal

2016 ◽  
Author(s):  
Saurabh Basu ◽  
Zhiyu Wang ◽  
Christopher Saldana
Keyword(s):  
Microstructure Evolution ◽  
Material Removal ◽  
A Priori ◽  
Orientation Imaging Microscopy ◽  
Machining Process ◽  
Textured Surfaces ◽  
Orientation Imaging ◽  
Using Data ◽  
Electron Back Scattered Diffraction ◽  
Tool Chatter

Tool chatter is envisaged as a technique to create undulations on fabricated biomedical components. Herein, a-priori designed topographies were fabricated using modulate assisted machining of oxygen free high conductivity copper. Subsequently, underpinnings of microstructure evolution in this machining process were characterized using electron back scattered diffraction based orientation imaging microscopy. These underpinnings were related to the unsteady mechanical states present during modulated assisted machining, this numerically modeled using data obtained from simpler machining configurations. In this manner, relationships between final microstructural states and the underlying mechanics were found. Finally, these results were discussed in the context of unsteady mechanics present during tool chatter, it was shown that statistically predictable microstructural outcomes result during tool chatter.

Two-Step Process Identification With Correlation Analysis and Least-Squares Parameter Estimation

1974 ◽  
Vol 96 (4) ◽  
pp. 426-432 ◽  
Author(s):  
R. Isermann ◽  
U. Bauer
Keyword(s):  
Correlation Analysis ◽  
Process Model ◽  
A Priori ◽  
Industrial Process ◽  
Computation Time ◽  
Small Computer ◽  
Nonparametric Model ◽  
Identification Method ◽  
On Line ◽  
Process Computer

An identification method is described which first identifies a linear nonparametric model (crosscorrelation function, impulse response) by correlation analysis and then estimates the parameters of a parametric model (discrete transfer function) and also includes a method for the detection of the model order and the time delay. The performance, the computational expense and the overall reliability of this method is compared with five other identification methods. This two-step identification method, which can be applied off-line or on-line, is especially suited to identification by process computers, since it has the properties: Little a priori knowledge about the structure of the process model; very short computation time; small computer storage; no initial values of matrices and parameters are necessary and no divergence is possible for the on-line version. Results of an on-line identification of an industrial process with a process computer are shown.

Estimating local CH4 emissions in the Upper Silesian Coal Basin using inverse modelling

2021 ◽  
Author(s):  
Sebastian Wolff ◽  
Friedemann Reum ◽  
Christoph Kiemle ◽  
Gerhard Ehret ◽  
Mathieu Quatrevalet ◽  
...  
Keyword(s):  
Remote Sensing ◽  
A Priori ◽  
Point Sources ◽  
Airborne Lidar ◽  
Inverse Modelling ◽  
Emission Rates ◽  
Coal Basin ◽  
Upper Silesian Coal Basin ◽  
The Individual ◽  
Modelling Approach

&lt;p&gt;Methane (CH&lt;sub&gt;4&lt;/sub&gt;) is the second most important anthropogenic greenhouse gas (GHG) with respect to radiative forcing. Since pre-industrial times, the globally averaged CH&lt;sub&gt;4&lt;/sub&gt; concentration in the atmosphere has risen by a factor of 2.5. A large fraction of global anthropogenic CH&lt;sub&gt;4&lt;/sub&gt; emissions originates from localized point sources, e.g. coal mine ventilation shafts. International treaties foresee GHG emission reductions, entailing independent monitoring and verification support capacities. Considering the spatially widespread distribution of point sources, remote sensing approaches are favourable, in order to enable rapid survey of larger areas. In this respect, active remote sensing by airborne lidar is promising, such as provided by the integrated-path differential-absorption lidar CHARM-F operated by DLR. Installed onboard the German research aircraft HALO, CHARM-F serves as a demonstrator for future satellite missions, e.g. MERLIN. CHARM-F simultaneously measures weighted vertical column mixing ratios of CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; below the aircraft. In spring 2018, during the CoMet field campaign, measurements were taken in the Upper Silesian Coal Basin (USCB) in Poland. The USCB is considered to be a European hotspot of CH&lt;sub&gt;4&lt;/sub&gt; emissions, covering an area of approximately 50 km &amp;#215; 50 km. Due to the high number of coal mines and density of ventilation shafts in the USCB, individual CH&lt;sub&gt;4&lt;/sub&gt; exhaust plumes can overlap. This makes simple approaches to determine the emission rates of single shafts, i.e. the cross-sectional flux method, difficult. Therefore, we use an inverse modelling approach to obtain an estimate of the individual emission rates. Specifically, we employ the Weather Research and Forecast Model (WRF) coupled to the CarbonTracker Data Assimilation Shell (CTDAS), an Ensemble Kalman Filter. CTDAS-WRF propagates an ensemble realization of the a priori CH&lt;sub&gt;4&lt;/sub&gt; emissions forward in space and time, samples the simulated CH&lt;sub&gt;4&lt;/sub&gt; concentrations along the measurement&amp;#8217;s flight path, and scales the a priori emission rates to optimally fit the measured values, while remaining tied to the prior. Hereby, we obtain a regularized a posteriori best emission estimate for the individual ventilation shafts. Here, we report on the results of this inverse modelling approach, including individual and aggregated emission estimates, their uncertainties, and to which extent the data are able to constrain individual emitters independently.&lt;/p&gt;

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