Analysis of properties of passenger traffic gravity model for linear network

2020 ◽  
pp. 23-28
Author(s):  
Alexander Valerievich Martynenko ◽  
◽  
Elena Gennadyevna Filippova ◽  

For the description of spatial distribution of passenger traffic in transport network a correspondence matrix is usually used. The elements of the matrix are the volumes of passenger traffic between each pair of network vertices. The elements of the matrix can be calculated with the use of mathematical apparatus based on the transport gravity model. The correspondence matrix gained by the above mentioned method depends on network structure, model parameters and initial data on the number of incoming and departing passengers for each network vertex. Moreover, the dependence has significantly non-linear character and can’t be presented in explicit form. This complicates the research of common properties of correspondence matrix and forecasting its change at modification of transport network, shift in transport behaviour of passengers (it affects the gravity model parameters) and at random fluctuations of number of incoming and departing passengers for network vertices. At the investigation of the mentioned dependence scientists use various approaches on the basis of both analytical apparatus and approximate methods. The paper presents classic simulation modeling for the analysis of the correspondence matrix and the volume of passenger traffic for the linear transport network calculated on its basis. The use of the proposed approach allowed determining that at random distribution of volumes of incoming and departing passengers the passenger traffic is also a random value distributed according to the normal law. Moreover, the authors gained the dependence between the passenger traffic and the parameter of gravity model connected with the average trip length. Besides, the authors studied the dependence of passenger traffic from the network scale.

2021 ◽  
pp. 10-16
Author(s):  
Olga Nikolaevna Ie ◽  

The paper studies indicators of passenger movement volumes on road transport for regional transport network that are gained on the basis of ride-sharing on-line services. For the processing of data arrays of common rides’ services web-scraping is used. The paper also investigates time distribution of passenger traffic that shows the filling of cars by passengers on various sections of a route. Peculiarities and dependencies of day fluctuations of passenger traffic for the Sverdlovsk region transport network are analysed. The author has considered a task of modeling of seasonal and cyclical fluctuations of passenger traffic volumes. She has used all necessary statistical procedures required for identification and assessment of model parameters and verification of its adequacy and accuracy. The time series model with polynomial smoothing is used for short-term forecasting that allows analysing the dynamics of passenger traffic, decreasing costs on monitoring of information on passenger traffic and allows using results for solving tasks of technological organization of public transport.


2010 ◽  
Vol 10 (1) ◽  
pp. 5-20
Author(s):  
Jakub Chmelík ◽  
Viktor Květoň ◽  
Miroslav Marada

Evaluation of Competitiveness of Rail Transport on Example of Connection Among Regional Capitals in Czechia The article is focused on evaluating the significance of rail passenger transport in transport contacts among regional capitals in Czechia representing the most important centres in the settlement hierarchy. The review of the particular connections works with the values of the year 2007 and is based on the relationship between supply and demand for rail passenger traffic. The evaluation is based on the number of rail links within the working day, while assuming that the supply is influenced by the location of the centre in the transport network and its position in the settlement hierarchy. Real demand data represent the number of tickets sold by the Czech Railways. Theoretical size of the interaction is obtained by application of the gravity model. Based on the final evaluation of indicators of supply and demand for rail traffic among regional capitals and their interactions, relations are described where demand is substantially below, respectively beyond the level of real supply and theoretical interaction, which is based on the importance of centres and their accessibility of the railway transport in time. In conclusion, the opportunities for the development of infrastructure in the selected connection in relation to transport planning are outlined, using the obtained results.


Author(s):  
S. Kaizerman ◽  
B. Benhabib ◽  
R. G. Fenton ◽  
G. Zak

Abstract A new robot kinematic calibration procedure is presented. The parameters of the kinematic model are estimated through a relationship established between the deviations in the joint variables and the deviations in the model parameters. Thus, the new method can be classified as an inverse calibration procedure. Using suitable sensitivity analysis methods, the matrix of the partial derivatives of joint variables with respect to robot parameters is calculated without having explicit expressions of joint variables as a function of task space coordinates (closed inverse kinematic solution). This matrix provides the relationship between the changes in the joint variables and the changes in the parameter values required for the calibration. Two deterministic sensitivity analysis methods are applied, namely the Direct Sensitivity Approach and the Adjoint Sensitivity Method. The new calibration procedure was successfully tested by the simulated calibrations of a two degree of freedom revolute-joint planar manipulator.


Author(s):  
Nicola Bonora ◽  
Luca Esposito ◽  
Simone Dichiaro ◽  
Paolo Folgarait

Safe and accurate methods to predict creep crack growth (CCG) are required in order to assess the reliability of power generation plants components. With advances in finite element (FE) methods, more complex models incorporating damage can be applied in the study of CCG where simple analytical solutions or approximate methods are no longer applicable. The possibility to accurately simulate CCG depends not only on the damage formulation but also on the creep model since stress relaxation, occurring in the near tip region, controls the resulting creep rate and, therefore, crack initiation and growth. In this perspective, primary and tertiary creep regimes, usually neglected in simplified creep models, plays a relevant role and need to be taken into account. In this paper, an advanced multiaxial creep model [1], which incorporates damage effects, has been used to predict CCG in P91 high chromium steel. The model parameters have been determined based on uniaxial and multiaxial (round notched bar) creep data over a wide range of stress and temperature. Successively, the creep crack growth in standard compact tension sample was predicted and compared with available experimental data.


Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3221
Author(s):  
Lucie Dal Soglio ◽  
Charles Danquigny ◽  
Naomi Mazzilli ◽  
Christophe Emblanch ◽  
Gérard Massonnat

The main outlets of karst systems are springs, the hydrographs of which are largely affected by flow processes in the unsaturated zone. These processes differ between the epikarst and transmission zone on the one hand and the matrix and conduit on the other hand. However, numerical models rarely consider the unsaturated zone, let alone distinguishing its subsystems. Likewise, few models represent conduits through a second medium, and even fewer do this explicitly with discrete features. This paper focuses on the interest of hybrid models that take into account both unsaturated subsystems and discrete conduits to simulate the reservoir-scale response, especially the outlet hydrograph. In a synthetic karst aquifer model, we performed simulations for several parameter sets and showed the ability of hybrid models to simulate the overall response of complex karst aquifers. Varying parameters affect the pathway distribution and transit times, which results in a large variety of hydrograph shapes. We propose a classification of hydrographs and selected characteristics, which proves useful for analysing the results. The relationships between model parameters and hydrograph characteristics are not all linear; some of them have local extrema or threshold limits. The numerous simulations help to assess the sensitivity of hydrograph characteristics to the different parameters and, conversely, to identify the key parameters which can be manipulated to enhance the modelling of field cases.


2019 ◽  
Vol 485 (2) ◽  
pp. 2806-2824 ◽  
Author(s):  
Linda Blot ◽  
Martin Crocce ◽  
Emiliano Sefusatti ◽  
Martha Lippich ◽  
Ariel G Sánchez ◽  
...  

ABSTRACT We study the accuracy of several approximate methods for gravitational dynamics in terms of halo power spectrum multipoles and their estimated covariance matrix. We propagate the differences in covariances into parameter constraints related to growth rate of structure, Alcock–Paczynski distortions, and biasing. We consider seven methods in three broad categories: algorithms that solve for halo density evolution deterministically using Lagrangian trajectories (ICE–COLA, pinocchio, and peakpatch), methods that rely on halo assignment schemes on to dark matter overdensities calibrated with a target N-body run (halogen, patchy), and two standard assumptions about the full density probability distribution function (Gaussian and lognormal). We benchmark their performance against a set of three hundred N-body simulations, running similar sets of approximate simulations with matched initial conditions, for each method. We find that most methods reproduce the monopole to within $5{{\ \rm per\ cent}}$, while residuals for the quadrupole are sometimes larger and scale dependent. The variance of the multipoles is typically reproduced within $10{{\ \rm per\ cent}}$. Overall, we find that covariances built from approximate simulations yield errors on model parameters within $10{{\ \rm per\ cent}}$ of those from the N-body-based covariance.


Aviation ◽  
2007 ◽  
Vol 11 (1) ◽  
pp. 28-34 ◽  
Author(s):  
Tatiana O. Blinova

At present the problem of forecasting passenger transport demand is of immense importance for air transport producers as well as for investors since investment efficiency is greatly affected by the accuracy and adequacy of the estimation performed. The aim of the present research is to analyze the possibility of using a neural network approach to forecast the expansion of the air‐transport network in Russia.


Author(s):  
Levi B. Wood ◽  
Roger D. Kamm ◽  
H. Harry Asada

This paper presents a method for deriving dynamic equations for Endothelial Cell (EC) motion and estimating parameters based on time lapse imagery of angiogenic sprout development. Angiogenesis is the process whereby a collection of endothelial cells sprout out from an existing blood vessel, degrade the surrounding scaffold and form a new blood vessel. Sprout formation requires that a collection of ECs all work together and coordinate their movements and behaviors. The process is initiated and guided by a collection of external growth factors. In addition, the individual cells communicate and respond to each other’s movements to behave in a coordinated fashion. The mechanics of cell coordination are extremely complex and include both chemical and mechanical communication between cells and between cells and the matrix. Despite the complexity of the physical system, with many variables that cannot be measured in real time, the ECs behave in a predictable manner based on just a few quantities that can be measured in real time. This work presents a methodology for constructing a set of simple stochastic equations for cell motion dependent only on quantities obtained from time lapse data observed from in vitro experiments. Model parameters are identified from time lapse data using a Maximum Likelihood Estimator.


2018 ◽  
Vol 26 (1) ◽  
pp. 83-88
Author(s):  
V. V. Ovsyanikov ◽  
D. M. Svynarenko ◽  
E. R. Beznosova ◽  
L. Z. Tsipko

Approximate and rigorous methods and results of calculations of electrical characteristics of rod arbitrarily curved antennas of the microwave range are investigated with the purpose of widening their varieties and increasing the accuracy of calculations of electrical parameters. An approximate calculation of the antennas is performed by the equivalent long line method, rigorous – by the integral equation method with respect to the distribution of the complex current at the antenna. An algorithm for the step-by-step development of curved rod antennas with included various concentrated loads and excitation nodes at arbitrary points are proposed. It is concluded that approximate methods are useful for a preliminary rough estimate of the input parameters of the antennas, and also as an initial approximation for their parametric synthesis and analysis. But strict methods can significantly expand the variety of studied antennas and improve the accuracy of calculations of their electrical parameters. A method is proposed for obtaining a stable solution of an integral equation by diagonalizing the matrix of coefficients of a system of equations. Basing on the results of the investigation of these antennas, new designs have been developed, a number of which have been introduced into production and operation. It is noted that for the first time in world practice the method of an integral equation described in this article for calculating such antennas has outpaced the development of known analogous methods and corresponding computer programs.


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