scholarly journals Macroscopic and Multi-Scale Models for Multi-Class Vehicular Dynamics with Uneven Space Occupancy: A Case Study

Axioms ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 102
Author(s):  
Maya Briani ◽  
Emiliano Cristiani ◽  
Paolo Ranut
Keyword(s):  
Road Network ◽  
Real Data ◽  
Second Order ◽  
Heavy Vehicles ◽  
First Order ◽  
Multi Scale ◽  
Stop And Go ◽  
Scale Models ◽  
Road Space

In this paper, we propose two models describing the dynamics of heavy and light vehicles on a road network, taking into account the interactions between the two classes. The models are tailored for two-lane highways where heavy vehicles cannot overtake. This means that heavy vehicles cannot saturate the whole road space, while light vehicles can. In these conditions, the creeping phenomenon can appear, i.e., one class of vehicles can proceed even if the other class has reached the maximal density. The first model we propose couples two first-order macroscopic LWR models, while the second model couples a second-order microscopic follow-the-leader model with a first-order macroscopic LWR model. Numerical results show that both models are able to catch some second-order (inertial) phenomena such as stop and go waves. Models are calibrated by means of real data measured by fixed sensors placed along the A4 Italian highway Trieste–Venice and its branches, provided by Autovie Venete S.p.A.

Barack Obama, being sharp

Gesture ◽  
2011 ◽  
Vol 11 (3) ◽  
pp. 241-270 ◽  
Author(s):  
Michael Lempert
Keyword(s):  
Information Structure ◽  
Precision Grip ◽  
Barack Obama ◽  
Second Order ◽  
First Order ◽  
Political Oratory ◽  
The Way

Gesture in political oratory and debate is renowned for its nonreferential indexical functions, for the way it purportedly can indicate qualities of speaker and materialize acts of persuasion — functions famously addressed in Quintilian’s classic writings but understudied today. I revisit this problematic through a case study of precision-grip (especially thumb to tip of forefinger) in Barack Obama’s debate performances (2004–2008). Cospeech gesture can index valorized attributes of speaker — not directly but through orders of semiotic motivation. In terms of first-order indexicality, precision-grip highlights discourse in respect of information structure, indicating focus. In debate, precision grip has undergone a degree of conventionalization and has reemerged as a second-order pragmatic resource for performatively “making a ‘sharp’, effective point.” Repetitions and parallelisms of precision grip in debate can, in turn, exhibit speaker-attributes, such as being argumentatively ‘sharp’, and from there may even partake in candidate branding.

3‐D imaging using higher order fast marching traveltimes

Geophysics ◽  
2002 ◽  
Vol 67 (2) ◽  
pp. 604-609 ◽  
Author(s):  
Alexander Mihai Popovici ◽  
James A. Sethian
Keyword(s):  
Real Data ◽  
Second Order ◽  
Data Sets ◽  
Velocity Analysis ◽  
Fast Marching ◽  
First Order ◽  
Interval Velocity ◽  
Migration Velocity Analysis ◽  
Imaging Results ◽  
The Common

Recently, fast marching methods (FMM) beyond first order have been developed for producing rapid solutions to the eikonal equation. In this paper, we present imaging results for 3‐D prestack Kirchhoff migration using traveltimes computed using the first‐order and second‐order FMM on several 3‐D prestack synthetic and real data sets. The second order traveltimes produce a much better image of the structure. Moreover, insufficiently sampled first order traveltimes can introduce consistent errors in the common reflection point gathers that affect velocity analysis. First‐order traveltimes tend to be smaller than analytic traveltimes, which in turn affects the migration velocity analysis, falsely indicating that the interval velocity was too low.

scholarly journals Magnetic Field Reconstruction for a Realistic Multi-Point, Multi-Scale Spacecraft Observatory

2021 ◽  
Vol 8 ◽  
Author(s):  
T. Broeren ◽  
K. G. Klein ◽  
J. M. TenBarge ◽  
Ivan Dors ◽  
O. W. Roberts ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Second Order ◽  
Data Sets ◽  
Reconstruction Method ◽  
Regular Tetrahedron ◽  
Order Method ◽  
First Order ◽  
Multi Scale ◽  
Order Reconstruction ◽  
The Magnetic Field

Future in situ space plasma investigations will likely involve spatially distributed observatories comprised of multiple spacecraft, beyond the four and five spacecraft configurations currently in operation. Inferring the magnetic field structure across the observatory, and not simply at the observation points, is a necessary step towards characterizing fundamental plasma processes using these unique multi-point, multi-scale data sets. We propose improvements upon the classic first-order reconstruction method, as well as a second-order method, utilizing magnetometer measurements from a realistic nine-spacecraft observatory. The improved first-order method, which averages over select ensembles of four spacecraft, reconstructs the magnetic field associated with simple current sheets and numerical simulations of turbulence accurately over larger volumes compared to second-order methods or first-order methods using a single regular tetrahedron. Using this averaging method on data sets with fewer than nine measurement points, the volume of accurate reconstruction compared to a known magnetic vector field improves approximately linearly with the number of measurement points.

scholarly journals Estimating hierarchical constructs using consistent partial least squares

2017 ◽  
Vol 117 (3) ◽  
pp. 459-477 ◽  
Author(s):  
Allard C.R. van Riel ◽  
Jörg Henseler ◽  
Ildikó Kemény ◽  
Zuzana Sasovova
Keyword(s):  
Hybrid Approach ◽  
Common Factors ◽  
Simulated Data ◽  
Real Data ◽  
Second Order ◽  
Business Research ◽  
Model Estimate ◽  
Content Type ◽  
First Order ◽  
Order Construct

Purpose Many important constructs of business and social sciences are conceptualized as composites of common factors, i.e. as second-order constructs composed of reflectively measured first-order constructs. Current approaches to model this type of second-order construct provide inconsistent estimates and lack a model test that helps assess the existence and/or usefulness of a second-order construct. The purpose of this paper is to present a novel three-stage approach to model, estimate, and test second-order constructs composed of reflectively measured first-order constructs. Design/methodology/approach The authors compare the efficacy of the proposed three-stage approach with that of the dominant extant approaches, i.e. the repeated indicator approach, the two-stage approach, and the hybrid approach by means of simulated data whose underlying population model is known. Moreover, the authors apply the three-stage approach to a real research setting in business research. Findings The study based on simulated data illustrates that the three-stage approach is Fisher-consistent, whereas the dominant extant approaches are not. The study based on real data shows that the three-stage approach is meaningfully applicable in typical research settings of business research. Its results can differ substantially from those of the extant approaches. Research limitations/implications Analysts aiming at modeling composites of common factors should apply the proposed procedure in order to test the existence and/or usefulness of a second-order construct and to obtain consistent estimates. Originality/value The three-stage approach is the only consistent approach for modeling, estimating, and testing composite second-order constructs made up of reflectively measured first-order constructs.

Generalizing generalized tries

2000 ◽  
Vol 10 (4) ◽  
pp. 327-351 ◽  
Author(s):  
RALF HINZE
Keyword(s):  
Type System ◽  
Search Tree ◽  
Second Order ◽  
First Order ◽  
Programming Paradigm ◽  
Arbitrary Signature ◽  
One Step ◽  
Rank 2 ◽  
Definition Of

A trie is a search tree scheme that employs the structure of search keys to organize information. Tries were originally devised as a means to represent a collection of records indexed by strings over a fixed alphabet. Based on work by C. P. Wadsworth and others, R. H. Connelly and F. L. Morris generalized the concept to permit indexing by elements built according to an arbitrary signature. Here we go one step further, and define tries and operations on tries generically for arbitrary datatypes of first-order kind, including parameterized and nested datatypes. The derivation employs techniques recently developed in the context of polytypic programming and can be regarded as a comprehensive case study in this new programming paradigm. It is well known that for the implementation of generalized tries, nested datatypes and polymorphic recursion are needed. Implementing tries for first-order kinded datatypes places even greater demands on the type system: it requires rank-2 type signatures and second-order nested datatypes. Despite these requirements, the definition of tries is surprisingly simple, which is mostly due to the framework of polytypic programming.

scholarly journals Modelling and peeling extended sources with shapelets: A Fornax A case study

2020 ◽  
Vol 37 ◽  
Author(s):  
J. L. B. Line ◽  
D. A. Mitchell ◽  
B. Pindor ◽  
J. L. Riding ◽  
B. McKinley ◽  
...  
Keyword(s):  
Test Performance ◽  
Angular Resolution ◽  
Real Data ◽  
Expected Improvement ◽  
Simulation Code ◽  
Multi Scale ◽  
Extended Sources ◽  
Murchison Widefield Array ◽  
Alternative Set

Abstract To make a power spectrum (PS) detection of the 21-cm signal from the Epoch of Reionisation (EoR), one must avoid/subtract bright foreground sources. Sources such as Fornax A present a modelling challenge due to spatial structures spanning from arc seconds up to a degree. We compare modelling with multi-scale (MS) CLEAN components to ‘shapelets’, an alternative set of basis functions. We introduce a new image-based shapelet modelling package, SHAMFI. We also introduce a new CUDA simulation code (WODEN) to generate point source, Gaussian, and shapelet components into visibilities. We test performance by modelling a simulation of Fornax A, peeling the model from simulated visibilities, and producing a residual PS. We find the shapelet method consistently subtracts large-angular-scale emission well, even when the angular resolution of the data is changed. We find that when increasing the angular resolution of the data, the MS CLEAN model worsens at large angular scales. When testing on real Murchison Widefield Array data, the expected improvement is not seen in real data because of the other dominating systematics still present. Through further simulation, we find the expected differences to be lower than obtainable through current processing pipelines. We conclude shapelets are worthwhile for subtracting extended galaxies, and may prove essential for an EoR detection in the future, once other systematics have been addressed.

scholarly journals Individual Cognitive Effort and Cognitive Transition During Organization Development

2018 ◽  
Vol 54 (4) ◽  
pp. 424-456 ◽  
Author(s):  
Philip J. Maxton ◽  
Gervase R. Bushe
Keyword(s):  
Organization Development ◽  
Change Process ◽  
Cognitive Effort ◽  
Qualitative Theory ◽  
Second Order ◽  
First Order ◽  
Emergent Change ◽  
Mind Set ◽  
Cognitive Transition

How do personal mind-sets change during an organization development intervention and how are these transitions associated with the intervention characteristics? In a qualitative theory-driven case study based in South Africa, the transitions of six individuals during an appreciative inquiry were scrutinized longitudinally for first-order and second-order changes. Five individuals showed first-order changes and two showed second-order changes. The engaging and emergent characteristic of the intervention explained the majority of these cognitive transitions. A third type of change in mind-set emerged in four of the cases: the development of an appreciative stance, which we classify as a form of cognitive effort rather than a cognitive transition. We conclude that interventions focusing on positivity may lead to participants developing an appreciative stance, but successful organization development might not occur without sufficient engagement in an emergent process. We provide some guidelines for practitioners for conducting an engaging emergent change process.

scholarly journals A theoretical framework for transitioning from patient-level to population-scale epidemiological dynamics: influenza A as a case study

2020 ◽  
Vol 17 (166) ◽  
pp. 20200230 ◽  
Author(s):  
W. S. Hart ◽  
P. K. Maini ◽  
C. A. Yates ◽  
R. N. Thompson
Keyword(s):  
Cohort Studies ◽  
Influenza A ◽  
Multi Scale ◽  
Patient Level ◽  
Modelling Framework ◽  
Level Data ◽  
Scale Models ◽  
Scale Modelling ◽  
Population Scale

Multi-scale epidemic forecasting models have been used to inform population-scale predictions with within-host models and/or infection data collected in longitudinal cohort studies. However, most multi-scale models are complex and require significant modelling expertise to run. We formulate an alternative multi-scale modelling framework using a compartmental model with multiple infected stages. In the large-compartment limit, our easy-to-use framework generates identical results compared to previous more complicated approaches. We apply our framework to the case study of influenza A in humans. By using a viral dynamics model to generate synthetic patient-level data, we explore the effects of limited and inaccurate patient data on the accuracy of population-scale forecasts. If infection data are collected daily, we find that a cohort of at least 40 patients is required for a mean population-scale forecasting error below 10%. Forecasting errors may be reduced by including more patients in future cohort studies or by increasing the frequency of observations for each patient. Our work, therefore, provides not only an accessible epidemiological modelling framework but also an insight into the data required for accurate forecasting using multi-scale models.

Sign in / Sign up

Export Citation Format

Share Document