Exploring the Relationship Between Average Speed, Speed Variation, and Accident Rates Using Spatial Statistical Models and GIS

2013 ◽  
Vol 5 (1) ◽  
pp. 27-45 ◽  
Author(s):  
Mohammed Quddus
Keyword(s):  
Statistical Models ◽  
Average Speed ◽  
Speed Variation ◽  
Accident Rates ◽  
The Relationship

scholarly journals Does Revitalizing the Center of Mid-Sized French Cities Reduce GHG Emissions from Commuting?

2021 ◽  
Vol 13 (4) ◽  
pp. 1851
Author(s):  
Alexis Poulhès ◽  
Angèle Brachet
Keyword(s):  
Land Use Planning ◽  
Statistical Models ◽  
Total Population ◽  
Ghg Emissions ◽  
Low Carbon ◽  
Trip Distance ◽  
Working People ◽  
Shrinking City ◽  
The Relationship ◽  
Positive Effect

Mid-sized cities are usually considered in the literature to be shrinking cities. Some policies promote right-sizing and others promote revitalization. The relationship between land-use planning and mobility having been established, the present research issue is focused on whether a policy of revitalizing the centers of mid-sized cities is favorable to low-carbon mobility. Our study investigates commuting trips through two indicators: commuting trip distance and car modal share. The increase in total population, the increase in the number of jobs per resident, the decrease in the unemployment rate, the increase in the rate of executives, the increase in the rate of working people in the population and the decrease in the residential vacancy rate all come from the censuses of 2006 and 2016. Statistical models based on individuals in 113 mid-sized cities, in which sociodemographic variables are introduced, show that at the level of agglomerations, no indicator has a simultaneously positive effect in the center and in the urban periphery. No indicator is entirely positive or negative on GHG emissions from commuting trips. While the increase in GHG emissions from commuting trips between 2006 and 2016 is significant in mid-sized cities (18%), a shift toward shrinking city centers is insufficient to change this trajectory.

scholarly journals Hedging Activities Information and Risk Management Committee Effectiveness: Malaysian evidence

2018 ◽  
Author(s):  
Azrul Bin Abdullah ◽  
Ku Nor Izah Ku Ismail
Keyword(s):  
Risk Management ◽  
Corporate Governance ◽  
Significant Influence ◽  
Statistical Models ◽  
Voluntary Disclosure ◽  
Annual Reports ◽  
Management Committee ◽  
Corporate Governance Mechanisms ◽  
The Relationship ◽  
Risk Management Committee

This study examines the extent of information about hedging activities disclosures within the annual reports of Main Market companies listed on Bursa Malaysia. The extent of hedging activities disclosures is captured through a 32-item-template, which consists of a mandatory and voluntary disclosure scores. The results of this study indicate that the extent of information on hedging activities disclosure is still insufficient among the sampled companies even though the disclosure scored is quite high. This study also examines the relationship between the existence of risk management committee (RMC), its characteristics and the extent of information on hedging activities disclosure in two separate statistical models. The regression results imply that the existence of RMC is positive but does not significantly influence the extent of information on hedging activities disclosure. However its characteristics (i.e. RMC independence and RMC meeting) have a significant influence. The findings may provide some meaningful insights to regulators, policymakers and researchers, towards the establishment of RMC as a part of the internal corporate governance mechanisms. In addition to its existence, the effectiveness of RMC also needs to be emphasised.

On the realizability of pressure–strain closures

2014 ◽  
Vol 755 ◽  
pp. 535-560 ◽  
Author(s):  
Aashwin A. Mishra ◽  
Sharath S. Girimaji
Keyword(s):  
Statistical Models ◽  
Flow Stability ◽  
Mean Flow ◽  
Model Formulation ◽  
Closure Model ◽  
Two Component ◽  
The Mean ◽  
The Relationship ◽  
Rapid Pressure ◽  
Domain Of Validity

AbstractThe realizability condition for statistical models of turbulence is augmented to ensure that not only is the Reynolds stress tensor positive semi-definite, but the process of its evolution is physically attainable as well. The mathematical constraints due to this process realizability requirement on the rapid pressure strain correlation are derived. The resulting constraints reveal important limits on the inter-component energy transfer and the consequent flow stability characteristics, as a function of the mean flow. For planar mean flows, the realizability constraints are most stringent for the case of purely sheared flows rather than elliptic flows. The relationship between the constraints and flow stability is explained. Process realizability leads to closure model guidance not only at the two-component (2C) limit of turbulence (as in the classical realizability approach) but throughout the anisotropy space. Consequently, the domain of validity and applicability of current models can be clearly identified for different mean flows. A simple framework for incorporating these process realizability constraints in model formulation is outlined.

The Frequency Analysis of the Crankshaft’s Speed Variation: A Reliable Tool for Diesel Engine Diagnosis

2000 ◽  
Vol 123 (2) ◽  
pp. 428-432 ◽  
Author(s):  
D. Taraza ◽  
N. A. Henein ◽  
W. Bryzik
Keyword(s):  
Diesel Engine ◽  
Data Acquisition System ◽  
Angular Speed ◽  
Internal Clock ◽  
Gas Pressure ◽  
Torsional Stiffness ◽  
Complex Nature ◽  
Average Speed ◽  
Speed Variation ◽  
Shaft Encoder

The speed variation of the crankshaft may be easily and accurately measured using a shaft encoder and counting the pulses of the internal clock of the data acquisition system. If the crankshaft would be a rigid body, the variation of its angular speed could be directly correlated to the total gas-pressure torque. Actually, the variation of the crankshaft’s speed has a complex nature being influenced by the torsional stiffness of the cranks, the mass moments of inertia of the reciprocating masses and the average speed and load of the engine. Analyzing only the lower harmonic orders of the speed variation spectrum can filter out the distortions produced by the dynamic response of the crankshaft. The information carried by these harmonic orders permits to establish correlations between measurements and the average gas pressure torque of the engine, and to detect malfunctions and identify faulty cylinders.

Relationship Between Volume-to-Capacity Ratios and Accident Rates

1997 ◽  
Vol 1581 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Min Zhou ◽  
Virginia P. Sisiopiku
Keyword(s):  
Traffic Volume ◽  
The Other ◽  
Explanatory Factors ◽  
Traffic Conflict ◽  
Single Vehicle ◽  
Driver Inattention ◽  
Detroit Area ◽  
Accident Rates ◽  
The Relationship ◽  
Shaped Pattern

The general relationships between hourly accident rates and hourly traffic volume/capacity ( v/c) ratios were examined. A 26 km (16 mi) segment of Interstate I-94 in the Detroit area was selected as the study segment. The v/c ratios were calculated from average hourly traffic volume counts collected in 1993 and 1994 from three permanent count stations. Accident rates were derived from hourly distributed number of accidents in the same 2 years. The correlation between v/c values and accident rates follows a general U-shaped pattern. The study of all observed accidents combined indicates that accident rates are highest in the very low hourly v/c range, decrease rapidly with increasing v/c ratio, and then gradually increase as the v/c ratio continues to increase. U-shaped models also explain the relationship between v/c and accident rates for weekdays and weekend days, multivehicle, rear-end, and property-damage-only accidents. On the other hand, single-vehicle, fixed-object, and turnover accidents, and accidents involving injury and fatality follow a generally decreasing trend with increasing v/c ratio. Traffic conflict is viewed as a major contributing factor to high accident rates observed in the high v/c range, whereas night conditions and driver inattention were identified as explanatory factors for the occurrence of high accident rates in the low v/c ranges.

scholarly journals Detection of the Lactate Threshold in Runners: What is the Ideal Speed to Start an Incremental Test?

2015 ◽  
Vol 45 (1) ◽  
pp. 217-224 ◽  
Author(s):  
José Luiz Dantas ◽  
Christian Doria
Keyword(s):  
Blood Lactate ◽  
Lactate Threshold ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Endurance Athletes ◽  
Incremental Test ◽  
Average Speed ◽  
Third Stage ◽  
The Relationship ◽  
The Ideal

Abstract Incremental tests on a treadmill are used to evaluate endurance athletes; however, no criterion exists to determine the intensity at which to start the test, potentially causing the loss of the first lactate threshold. This study aimed to determine the ideal speed for runners to start incremental treadmill tests. The study consisted of 94 runners who self-reported the average speed from their last competitive race (10-42.195 km) and performed an incremental test on a treadmill. The speeds used during the first three test stages were normalised in percentages of average competition speed and blood lactate concentration was analysed at the end of each stage. The relationship between speed in each stage and blood lactate concentration was analysed. In the first stage, at an intensity corresponding to 70% of the reported average race speed, only one volunteer had blood lactate concentration equal to 2 mmol·L-1, and in the third stage (90% of the average race speed) the majority of the volunteers had blood lactate concentration ≥2 mmol·L-1. Our results demonstrated that 70% of the average speed from the subject’s last competitive race - from 10 to 42.195 km - was the best option for obtaining blood lactate concentration <2 mmol·L-1 in the first stage, however, 80% of the average speed in marathons may be a possibility. Evaluators can use 70% of the average speed in competitive races as a strategy to ensure that the aerobic threshold intensity is not achieved during the first stage of incremental treadmill tests.

scholarly journals Multi-lane Changing Model with Coupling Driving Intention and Inclination

2017 ◽  
Vol 29 (2) ◽  
pp. 185-192 ◽  
Author(s):  
Jiangfeng Wang ◽  
Chang Gao ◽  
Zhouyuan Zhu ◽  
Xuedong Yan
Keyword(s):  
Risk Factor ◽  
Lane Changing ◽  
Traffic Demand ◽  
Average Speed ◽  
Slowing Down ◽  
Behavioural Characteristics ◽  
Proposed Model ◽  
Density Flow ◽  
The Impact ◽  
The Relationship

Considering the impact of drivers’ psychology and behaviour, a multi-lane changing model coupling driving intention and inclination is proposed by introducing two quantitative indices of intention: strength of lane changing and risk factor. According to the psychological and behavioural characteristics of aggressive drivers and conservative drivers, the safety conditions for lane changing are designed respectively. The numerical simulations show that the proposed model is suitable for describing the traffic flow with frequent lane changing, which is more consistent with the driving behaviour of drivers in China. Compared with symmetric two-lane cellular automata (STCA) model, the proposed model can improve the average speed of vehicles by 1.04% under different traffic demands when aggressive drivers are in a higher proportion (the threshold of risk factor is 0.4). When the risk factor increases, the average speed shows the polarization phenomenon with the average speed slowing down in big traffic demand. The proposed model can reflect the relationship among density, flow, and speed, and the risk factor has a significant impact on density and flow.

STUDENTS’ EMERGENT ARTICULATIONS OF STATISTICAL MODELS AND MODELING IN MAKING INFORMAL STATISTICAL INFERENCES

2017 ◽  
Vol 16 (2) ◽  
pp. 116-143
Author(s):  
HANA MANOR BRAHAM ◽  
DANI BEN-ZVI
Keyword(s):  
Statistical Models ◽  
Statistics Education ◽  
Fundamental Aspect ◽  
School Students ◽  
Real World Data ◽  
Research Journal ◽  
Statistical Inferences ◽  
Exploratory Data ◽  
The Relationship ◽  
Models And Modeling

A fundamental aspect of statistical inference is representation of real-world data using statistical models. This article analyzes students’ articulations of statistical models and modeling during their first steps in making informal statistical inferences. An integrated modeling approach (IMA) was designed and implemented to help students understand the relationship between sample and population, as well as reasoning with models and modeling. We explore the articulations of a pair of primary school students, who had previously participated in the Connections Project exploratory data analysis (EDA) activities, and suggest an emergent conceptual framework for reasoning with statistical models and modeling. We shed light on ideas of statistical models and modeling that can emerge among primary students and how they articulate those ideas. Implications for teaching and research are discussed. First published November 2017 at Statistics Education Research Journal Archives

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