scholarly journals Geometry deviation effects of railway catenaries on pantograph–catenary interaction: a case study in Norwegian Railway System

2021 ◽  
Author(s):  
Yang Song ◽  
Tengjiao Jiang ◽  
Petter Nåvik ◽  
Anders Rønnquist
Keyword(s):  
Contact Force ◽  
High Frequency ◽  
Loss Rate ◽  
Lumped Mass ◽  
Railway Network ◽  
The Monte Carlo Method ◽  
Spectrum Density ◽  
Railway System ◽  
Geometry Deviation

AbstractThis paper presents a non-contact measurement of the realistic catenary geometry deviation in the Norwegian railway network through a laser rangefinder. The random geometry deviation is included in the catenary model to investigate its effect on the pantograph–catenary interaction. The dispersion of the longitudinal deviation is assumed to follow a Gaussian distribution. A power spectrum density represents the vertical deviation in the contact wire. Based on the Monte Carlo method, several geometry deviation samples are generated and included in the catenary model. A lumped mass pantograph with flexible collectors is employed to reproduce the high-frequency behaviours. The stochastic analysis results indicate that the catenary geometry deviation causes a significant dispersion of the pantograph–catenary interaction response. The contact force standard deviations measured by the inspection vehicle are within the scope of the simulation results. A critical cut-off frequency that covers 1/16 of the dropper interval is suggested to fully describe the effect of the catenary geometry deviation on the contact force. The statistical minimum contact force is recommended to be modified according to the tolerant contact loss rate at high frequency. An unpleasant interaction performance of the pantograph–catenary can be expected at the catenary top speed when the random catenary geometry deviation is included.

scholarly journals A Sensitivity Analysis of Train Speed and its Effect on Railway Capacity

2014 ◽  
Vol 1061-1062 ◽  
pp. 1208-1212
Author(s):  
Bayan Bevrani ◽  
Robert Burdett ◽  
Prasad K.D.V. Yarlagadda
Keyword(s):  
Sensitivity Analysis ◽  
Cost Effective ◽  
Railway Network ◽  
Capacity Model ◽  
The Future ◽  
Railway System ◽  
Train Speed ◽  
The Absolute ◽  
Railway Capacity

Increasing train speeds is conceptually a simple and straight forward method to expand railway capacity, for example in comparison to other more extensive and elaborate alternatives. In this article an analytical capacity model has been investigated as a means of performing a sensitivity analysis of train speeds. The results of this sensitivity analysis can help improve the operation of this railway system and to help it cope with additional demands in the future. To test our approach a case study of the Rah Ahane Iran (RAI) national railway network has been selected. The absolute capacity levels for this railway network have been determined and the analysis shows that increasing trains speeds may not be entirely cost effective in all circumstances.

Case study: Simulation and control of high frequency noise for commercial vehicle cab considering leak

2019 ◽  
Vol 67 (4) ◽  
pp. 315-329
Author(s):  
Rongjiang Tang ◽  
Zhe Tong ◽  
Weiguang Zheng ◽  
Shenfang Li ◽  
Li Huang
Keyword(s):  
High Frequency ◽  
Commercial Vehicle ◽  
Frequency Noise ◽  
High Frequency Noise ◽  
Simulation And Control ◽  
And Control

What Kind of People Use Carsharing for Commuting? Case Study in Shanghai

2019 ◽  
Vol 2673 (5) ◽  
pp. 770-778 ◽  
Author(s):  
Jianhong Ye ◽  
Daoge Wang ◽  
Hua Zhang ◽  
Hong Yang
Keyword(s):  
High Frequency ◽  
Urban Areas ◽  
Descriptive Analysis ◽  
User Characteristics ◽  
Logistic Regression Models ◽  
Highly Educated ◽  
Suburban Areas ◽  
Commuting Mode ◽  
Study Offer

Carsharing as a service has been growing rapidly worldwide. Its expansion has drawn wide attention in the research community with regard to the underlying driving factors and user characteristics. Despite these extensive investigations, there are still limited studies focusing on the examination of users using carsharing as a commuting mode. The answers to questions such as what kind of people would like to use carsharing for commuting and why they frequently use carsharing to commute are not clear. To enrich our understanding of these problems, this paper aims to investigate carsharing commuters in a mega city. Specifically, it intends to integrate the actual user order data with survey data from 1,920 participants to uncover the characteristics of carsharing commuters. Data from the Evcard carsharing systems in Shanghai were explicitly analyzed. Through descriptive analysis and logistic regression models, the characteristics and critical factors that affect the choice of carsharing as a commuting mode were captured. The results show that: 1. carsharing commuters mostly live or work in suburban areas in which public transport accessibility is limited; 2. carsharing commuters are more likely to be highly educated, in a higher income bracket, and older than other carsharing members; 3. high-frequency carsharing commuters own a reduced number of private cars; and 4. those high-frequency carsharing commuters with higher income are less sensitive to the carsharing costs caused by congestion. The findings in the study offer some insights into carsharing commuters and provide some supportive information for considering policies in developing carsharing systems in urban areas.

Research on SVM Line Loss Rate Prediction Based on Heuristic Algorithm

2013 ◽  
Vol 291-294 ◽  
pp. 2164-2168 ◽  
Author(s):  
Li Tian ◽  
Qiang Qiang Wang ◽  
An Zhao Cao
Keyword(s):  
Support Vector Machine ◽  
Heuristic Algorithm ◽  
Support Vector Machine Model ◽  
Loss Rate ◽  
Heuristic Algorithms ◽  
Support Vector ◽  
Machine Model ◽  
Rate Prediction ◽  
Line Loss

With the characteristic of line loss volatility, a research of line loss rate prediction was imperatively carried out. Considering the optimization ability of heuristic algorithm and the regression ability of support vector machine, a heuristic algorithm-support vector machine model is constructed. Case study shows that, compared with other heuristic algorithms’, the search efficiency and speed of genetic algorithm are good, and the prediction model is with high accuracy.

scholarly journals THE RAILWAY NETWORK AND THE PROCESS OF POPULATION CONCENTRATION IN SPAIN, 1900-2001

2014 ◽  
Vol 32 (3) ◽  
pp. 351-379 ◽  
Author(s):  
Xavier Franch-Auladell ◽  
Mateu Morillas-Torné ◽  
Jordi Martí-Henneberg
Keyword(s):  
Total Population ◽  
Census Data ◽  
Population Distribution ◽  
Historical Analysis ◽  
Railway Network ◽  
Population Concentration ◽  
Central Hypothesis ◽  
Municipal Level

ABSTRACTThis paper proposes a methodology for quantifying the territorial impact on population distribution of the railway. The central hypothesis is that access to railway services provides the best-connected areas with a long-term comparative advantage over others that are less accessible. Carrying out a historical analysis and providing comparable data at the municipal level allows us to determine the extent to which the railway has fostered the concentration of population within its immediate surroundings. The case study presented here is that of Spain between 1900 and 2001, but the same methodology could equally be applied to any other country for which the required data are available. In this case, key data included a Geographic Information System with information about both the development of the railway network and census data relating to total population at the municipal level. The results obtained suggest the relevance of this methodology, which makes it possible to identify the periods and areas in which this influence was most significant.

HFTViz: Visualization for the exploration of high frequency trading data

2021 ◽  
pp. 147387162110649
Author(s):  
Javad Yaali ◽  
Vincent Grégoire ◽  
Thomas Hurtut
Keyword(s):  
Portfolio Management ◽  
High Frequency ◽  
High Speed ◽  
High Frequency Trading ◽  
Domain Experts ◽  
Risk Return ◽  
Visualization Tools ◽  
Liquidity Measures ◽  
Trading Volumes

High Frequency Trading (HFT), mainly based on high speed infrastructure, is a significant element of the trading industry. However, trading machines generate enormous quantities of trading messages that are difficult to explore for financial researchers and traders. Visualization tools of financial data usually focus on portfolio management and the analysis of the relationships between risk and return. Beside risk-return relationship, there are other aspects that attract financial researchers like liquidity and moments of flash crashes in the market. HFT researchers can extract these aspects from HFT data since it shows every detail of the market movement. In this paper, we present HFTViz, a visualization tool designed to help financial researchers explore the HFT dataset provided by NASDAQ exchange. HFTViz provides a comprehensive dashboard aimed at facilitate HFT data exploration. HFTViz contains two sections. It first proposes an overview of the market on a specific date. After selecting desired stocks from overview visualization to investigate in detail, HFTViz also provides a detailed view of the trading messages, the trading volumes and the liquidity measures. In a case study gathering five domain experts, we illustrate the usefulness of HFTViz.

Generation of extra and very low-frequency (ELF/VLF) radiation by ionospheric electrojet modulation using high-frequency (HF) heating waves

2002 ◽  
Vol 68 (4) ◽  
pp. 267-284 ◽  
Author(s):  
S. P. KUO
Keyword(s):  
High Frequency ◽  
Thermal Instability ◽  
Loss Rate ◽  
Inelastic Collision ◽  
Modulation Frequency ◽  
Low Frequency ◽  
Heating Power ◽  
Very Low Frequency ◽  
Hf Heating ◽  
Heating Wave

Extra and very low-frequency (ELF/VLF) wave generation by modulated polar electrojet currents is studied numerically. Through Ohmic heating by the amplitude-modulated high-frequency heating wave, the conductivity and thus the current of the electrojet are modulated accordingly to set up the ionospheric antenna current. Stimulated thermal instability, which can further enhance the electrojet current modulation, is studied. It is first analysed analytically to determine the threshold heating power for its excitation. The nonlinear evolutions of the generated ELF/VLF waves enhanced by the instability are then studied numerically. Their spectra are also evaluated. The field intensity of the emission at the fundamental modulation frequency is found to increase with the modulation frequency in agreement with the Tromso observations. The efficiency enhancement by the stimulated thermal instability is hampered by inelastic collisions of electrons with neutral particles (mainly due to vibration excitation of N2), which cause this instability to saturate at low levels. However, the electron inelastic collision loss rate drops rapidly to a low value in the energy regime from 3.5 to 6 eV. As the heating power exceeds a threshold level, significant electron heating enhanced by the instability is shown, which indeed causes a steep drop in the electron inelastic collision loss rate. Consequently, this instability saturates at a much higher level, resulting to a near step increase (of about 10–13 dB depending on the modulation wave form) in the spectral intensity of ELF radiation. The dependence of the threshold power of the HF heating wave on the modulation frequency is determined.

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