基于Logistic曲线和Gompertz曲线的最优组合沉降预测模型及其应用

地基的全过程沉降量与时间呈S形曲线关系，可用Logistic模型和Gompertz模型较好地描述。根据I_ogistic曲线和Gompertz曲线的共性和个性，引用最优加权组合建模理论，以组合模型的对数误差平方和最小为目标函数来确定最优的加权系数，建立了最优加权几何平均组合沉降预测模型。通过工程实例，验证了该最优组合沉降预测模型的可行性。对比计算结果表明，最优组合沉降预测模型的精度不仅比Logistic模型和Gompertz模型的预测精度要高，而且可靠性也优于各个单一预测的模型，是地基沉降观测资料的一种有效分析方法。     

公交驾驶员心理状况影响因素分析与疾病判别模型

为对公交驾驶员心理疾病实现精准干预,维护乘客生命及公共交通安全,本文通过分析公 交驾驶员心理状况影响因素构建心理疾病类型判别模型。选用由基本信息、身体状况、生活状 态、驾驶行为、组织认同感、人格特征以及职业压力与工作倦怠问卷组成的公交驾驶员心理健康 状况调查问卷,对400名城市公交驾驶员展开问卷调查研究,通过皮尔逊相关性检验分析心理状 况影响因素,利用K-means聚类算法和多元Logistic回归模型判别和分析心理疾病,提出相应干 预措施。结果表明：人格冷怒和驾驶行为、身体状况、生活状态、组织认同感显著正相关,职业压 力与工作倦怠和这4个影响因素显著负相关,相关性均较强,因此,构建心理疾病判别模型时排除 与多个影响因素均呈较强相关性的人格冷怒、职业压力与工作倦怠这两个影响因素;被调查的公 交驾驶员中,心理状态良好型、轻度心理疾病型、严重心理疾病型占比分别为52%、34%、14%;公 交驾驶员心理疾病类型与身体状况、驾驶行为以及生活状态显著正相关,与驾驶行为的相关性最 强,身体状况次之,生活状态最弱。     

What are the determinants in making people free riders in proof-of-payment transit systems? Evidence from Italy

Nowadays, in proof-of-payment transit systems, fare evasion is provoking strong interest in public transport companies (PTCs) due to the relevant economic losses, social inequity and increased levels of violence affecting personal security. Therefore, there is the need to recognize possible fare evaders. By using 2177 on-board personal interviews, gathered from an Italian PTC, and logistic regression models, we isolate determinants of possible free-rider passengers and, hence, those whom it might be advisable to target in order to capitalize on the effect of the application of countermeasures on fare evasion put forward by the local PTC. We show that males, younger than 26 years, with a low education level, unemployed and/or students and without an alternative mode of transport other than the bus are more probably fare evaders. Moreover, people who make trips of shorter than 15 min, who are systematic users and are not satisfied with the service are possible fare evaders. Finally, we found that a low level of inspection, knowledge of fines and previous ticket violations are determinants which make people more prone to evade fares. These outcomes are very useful, because, to the best of our knowledge, they represent the first empirical contribution showing the determinants which help evaluate the propensity to be a fare evader, in probabilistic terms. Moreover, they could help PTCs understand who might be a fare evader, in order to anticipate suitable countermeasures.     

Modeling taxi drivers’ decisions for improving airport ground access: John F. Kennedy airport case

Taxi service is an important component of airport ground access, which affects the economic competitiveness of an airport and its potential positive impact on the surrounding region. Airports across the globe experience both taxi shortages and excesses due to various factors such as the airport’s proximity to the city center, timing and frequency of flights, and the fare structure. Since taxi drivers are independent entities whose decisions affect the taxi supply at airports, it is important to understand taxi drivers’ decision mechanisms in order to suggest policies and to maintain taxi demand and supply equilibrium at the airports. In this paper, New York City (NYC) taxi drivers’ decisions about airport pick-ups or cruising for customers at the end of each trip is modeled using logistic regression based on a large taxi GPS dataset. The presented approach helps to quantify the potential impacts of parameters and to rank their influence for policy recommendations. The results reveal that spatial variables (mainly related to proximity) have the highest impact on taxi drivers’ airport pickup decisions, followed by temporal, environmental and driver-shift related variables. Along with supplementary information from unstructured taxi driver interviews, the model results are used to suggest policies for the improvement of John F. Kennedy (JFK) airport’s ground access and passenger satisfaction, i.e. the implementation of taxi driver frequent airport server punch cards and a time-specific ride share program.     

根面龋的危险因素Logistic回归分析

目的分析引起根面龋的危险因素。方法采用分层随机抽样方法,对唐山市600名40岁以上中老年人进行口腔健康检查,数据应用SAS 8.0软件进行Logistic多因素回归分析。结果Logistic多因素回归分析表明年龄、口腔牙石指数、义齿修复和牙龈退缩4个因素是中老年人根面龋的相关危险因素,竖式刷牙、使用含氟牙膏是根龋的保护性因素。结论年龄、口腔牙石指数、义齿修复和牙龈退缩是根面龋的相关危险因素。     

物流企业信息化水平评估体系研究

简述了建立企业信息化水平评价体系的意义及其应当遵循的原则.提出了物流企业信息化水平评估指标体系,并对各个指标进行相关分析.     

Estimation of the determinants of bicycle mode share for the journey to work using census data

A model is presented that relates the proportion of bicycle journeys to work for English and Welsh electoral wards to relevant socio-economic, transport and physical variables. A number of previous studies have exploited existing disaggregate data sets. This study uses UK 2001 census data, is based on a logistic regression model and provides complementary evidence based on aggregate data for the determinants of cycle choice. It suggests a saturation level for bicycle use of 43%. Smaller proportions cycle in wards with more females and higher car ownership. The physical condition of the highway, rainfall and temperature each have an effect on the proportion that cycles to work, but the most significant physical variable is hilliness. The proportion of bicycle route that is off-road is shown to be significant, although it displays a low elasticity (+0.049) and this contrasts with more significant changes usually forecast by models constructed from stated preference based data. Forecasting shows the trend in car ownership has a significant effect on cycle use and offsets the positive effect of the provision of off-road routes for cycle traffic but only in districts that are moderately hilly or hilly. The provision of infrastructure alone appears insufficient to engender higher levels of cycling.

Logistic modeling of the equilibrium speed-density relationship

The fundamental diagram, as the graphical representation of the relationships among traffic flow, speed, and density, has been the foundation of traffic flow theory and transportation engineering. Seventy-five years after the seminal Greenshields model, a variety of models have been proposed to mathematically represent the speed-density relationship which underlies the fundamental diagram. Observed in these models was a clear path toward two competing goals: mathematical elegance and empirical accuracy. As the latest development of such a pursuit, this paper presents a family of speed-density models with varying numbers of parameters. All of these models perform satisfactorily and have physically meaningful parameters. In addition, speed variation with traffic density is accounted for; this enables statistical approaches to traffic flow analysis. The results of this paper not only improve our understanding of traffic flow but also provide a sound basis for transportation engineering studies.     

Modeling wrong-way crashes and fatalities on arterials and freeways

Wrong way driving (WWD) research and mitigation measures have primarily focused on limited access facilities. This is most likely due to the higher incidence of fatal WWD crashes with dramatic consequences on freeways, media attention, and a call for innovative solutions to address the problem. While public agencies and published literature address WWD incidence on freeway systems, the crash analyses on non-limited access facilities, i.e., arterial corridors, remains untouched. This research extends previous works and attempts to provide many new perspectives on arterial WWD incidence. In particular, one work showed that while WWD fatalities are more likely to occur on freeways, the likelihood of these crashes is higher on arterials. Hence this work with univariate and multivariate analyses of WWD and non-WWD crashes, and fatal and non-fatal WWD incidents. Results show the impressive negative impacts of alcohol use, driver defect, nighttime and weekend incidence, poor street lighting, low traffic volumes, rural geography, and median and shoulder widths. The objective here is to highlight the need for paying greater attention to WWD crashes on arterial corridors as is done with fatal WWD incidents on freeway systems. It suffices to say that while engineering countermeasures should evolve from the traditional signing and pavement markings to connected vehicle technology applications, there is a clear and compelling need to focus on educational campaigns specifically targeting drunken driving, and enforcement initiatives with an objective to mitigate WWD in the most efficient manner possible.     

Factors associated with crashes due to overcorrection or oversteering of vehicles

The objective of this research is to identify factors associated with crashes due to overcorrection or oversteering of vehicles. Crash data was collected from 2011 to 2013 for the State of North Carolina in the United States. Logistic regression modeling was used to analyze crash data because of the dichotomous nature of the dependent variable (overcorrection or oversteering). The crash involvement due to overcorrection or oversteering of a vehicle decreased as the age of the driver increased. Drivers are 2.22 times more likely to overcorrect or oversteer when ill, 3.44 times more likely to overcorrect or oversteer when under fatigue, and 1.61 times more likely to overcorrect or oversteer when fallen asleep compared to normal physical conditions. Overall, driver characteristics and speed limit tend to play a major role in overcorrection or oversteering of vehicles. Programs to reduce impaired driving might help in the reduction of overcorrection or oversteering related crash fatalities or injuries. Additionally, training and driver education programs focusing on identified factors associated with crashes due to overcorrection or oversteering of vehicles will benefit drivers on how to respond during emergency or panic situations.