从线路技术指标及性质定位方面分析城市常规公交线路存在的主要问题,提出线路调整优化的11条原则.分析城市公交线路的技术指标和效益指标,选择调整优化线路.对调整优化线路从线路客流分担率、复线系数-客流量关系图、平均满载率调整值-复线系数关系图进行综合分析,选择待调整优化站点.考虑现状场站布局、线路布设、线网密度、客流分布对待调整线路进行调整优化,对于具有多重性质的线路可对其进行适当拆分并合理调整.实例应用表明,该方法操作方便,提高了调整线路及整个线网的运行质量.

Aiming at contradictory expense relationship between highway charging system and vehicle waiting services,reasonably design and control highway charging system,analyze optimum service rate in charging system,establish queuing model and infer equation of higher degree for optimum service rate.Estimate the initial value by utilizing MATLAB fitting function curve graph,adopt Netwon iterative method to solve the equation,i.e.optimum service rate in charging system,thus solving the contradiction of expenses between highway charging system and vehicle waiting service so as to minimum the sum consumed.Combining with the practice,discuss the most economic and reasonable service rate in queue of M / M /1 / ∞ / ∞ / FCFS.The result shows that the practicality of this method is strong and the accuracy is high.

Based on the theory of fuzzy neural network and hierarchical intelligent control, establish system architecture of freeway multi-ramp control, put forward coordination control algorithm of multi-ramp, provide a systemic solution method to realize multi-ramp intelligent control. This method is relatively simple and easy to expand, simultaneity independent on specific freeway mathematical models, possess well adaptability. Moreover use the Matlab software carry through simulation, simulation result show that the algorithm is feasible and effective.

交通工程双语教学在交通运输人才的培养中具有重要的地位,双语教学方法的研究既有必要性又有紧迫性.根据高等学校的教育目标,结合知识结构的要求,立足于本课程教学实践中的体会,通过交通工程学双语教学的教学体系建设、教学方法研究及教学实践效果分析,提出了交通工程学双语教学的教学思路,以期取得较好的教学效果.

To ensure traffic flow on urban expressway running safely and efficiently and perfect the designing standard of interchange spacing, it is necessary to study the length of acceleration and deceleration lane on urban expressway. Based on the vehicles' running characteristics, the acceleration lane was divided into three sections, namely acceleration section, waiting merging section and width transition section. Applying dynamics theory, the models calculating the length of acceleration section and width transition section were got. By combining probability theory and differential method and taking main lane traffic volume into consideration, the model calculating the length of waiting merging section was established as well. Then, the twice deceleration theory put forward by AASHTO(American Association of State Highway and Transportation Officials) was adopted to analyze the vehicles' running process on deceleration lane. The deceleration lane was divided into three sections, too, i.e. width transition section, the first and second deceleration section. Applying the dynamics theory again, the model calculating the length of width transition section was got. Applying dynamics theory and taking drivers' driving comfort into consideration, the models calculating the length of the first and second deceleration section were established as well. And then, taking mainline lane vehicles' time headway distribution and mainline lane and ramp vehicles' velocity combination into consideration, the length values of acceleration and deceleration lane on urban expressway were calculated. The calculation results indicate that the length of acceleration and deceleration lane increases with the increase of mainline lane vehicles' velocity and decreases with the increase of ramp vehicles' velocity.

Aims at the complex and dynamic nature of traffic flow in mountain expressway tunnel, through the analysis of change characteristics of traffic flow, based on BP network improve the existing expressway traffic flow model, this thesis puts forward the Elman dynamic neural network model of traffic flow predicting in mountain expressway tunnel. In practice, this model has the strong operational, we adopt it to simulate and forecast the traffic flow of JingZhu expressway ShaoGuan section, reach the purpose of theory and reality unify. Through the analysis of the traffic flow characteristics this thesis could provide a viable research idea for the rational and orderly flowing of tunnel traffic flow.

Background and purpose:Stroke is a heavy economic and health burden for the patients and society. This study aimed to evaluate hospital length of stay (LOS) by admission characteristics and costs correlated with medical insurance status for cerebral infarction in a medium-sized city in China.Methods:A total of 557 consecutive patients with principal diagnosis of cerebral infarction were enrolled. Admission characteristics, LOS, and costs were retrospectively analyzed.Results:The mean LOS was 18.5 days (median, 16 days). Our analysis demonstrated that medical insurance status, stroke severity (National Institutes of Health Stroke Scale score, Functional Independence Measure cognitive and motor score, Glasgow coma scale), Oxfordshire Community Stroke Project (OCSP) classification, some comorbidities (coronary heart disease, chronic obstructive pulmonary disease, and hyperlipemia), and raised leukocytes were the main explanatory factors for LOS by stepwise multiple regression model. The mean per patient costs were US$ 983.0, and mean daily costs US$ 67.0. Drugs were the most expensive cost subtype, all subtypes costs except non-medical care were significantly higher in patients with state medicine than in those with new cooperative medical scheme (NCMS) (P < 0.001).Conclusion:Stroke severity, OCSP classification, raised leukocytes on admission, some comorbidities, and medical insurance status may help to predict LOS for patients with cerebral infarction. Healthcare expenditures were heavy burdens to inhabitants. State medicine patients could shorten unnecessary LOS to improve the resources allocation and cost-efficiency.

Defining equivalent people group to describe the non-motorized vehicles' and pedestrians' effect on motor vehicles, traffic flow priority of urban road unsignalized T-intersection was ranked renewedly, and it was divided into five grades. Then based on gap acceptance theory, potential capacity models of each subordinate traffic flow were established. By means of probability theory, the adjustment factor of equivalent people groups to motor traffic flow was obtained. Taking prior traffic flows' effects on subordinate traffic flows into consideration, movement capacity models of subordinate traffic flows were established. Based on the analysis above, the capacity calculation model of Urban Road Unsignalized T-intersection was obtained. Case study indicates that the capacity of motor vehicles was greatly reduced because of the non-motorized vehicles' and pedestrians' effect.

This paper quantitatively analyzes the effect of road section crosswalks on urban road capacity and the running characteristics of pedestrians, bicycles, and electric bicycles when they pass through a crosswalk were also studied. The equivalent people group was also defined to describe the common effects of pedestrians, bicycles, and electric bicycles on vehicles’ running. Taking sample stability and application convenience into consideration, an analysis period of 15 minutes was adopted. Then, by means of statistical analysis, the values of equivalent people number, average equivalent people groups’ time headway, and equivalent people groups’ number of each 15 minutes were obtained. By means of a regression analysis, the 11 kinds of regression models between 15 minutes equivalent people number and average equivalent people groups’ time headway, and the 11 kinds of regression models between 15 minutes equivalent people number and equivalent people groups’ number were obtained. Based on the correlation coefficient values and application convenience, the inverse function was adopted to describe the relationship between equivalent people number and average equivalent people groups’ time headway, and the cubic function was adopted to describe the relationship between equivalent people number and equivalent people groups’ number. And then, the method of time resource occupancy was adopted to analyze the effect of pedestrians, bicycles, and electric bicycles on urban road capacity, and the adjustment factors under the condition of whether there is a signal for pedestrians to pass through a crosswalk were obtained. Research indicates that the average equivalent people groups’ time headway decreases with the increase of equivalent people number, and the equivalent people groups’ number firstly increases and then decreases with the increase of equivalent people number. Case study indicates that when the traffic volume of pedestrians, bicycles, and electric bicycles is relatively high, signal control can effectively reduce the impact of road section crosswalks on urban road capacity.

随着交通运输技术的快速发展,作为系统介绍交通运输知识的交通工程学的教学改革势在必行。交通工程学这门课程理论性和实践性都较强,采用传统的方式教学,难以取得好的教学效果。根据高等学校的教育目标,结合知识结构的要求,立足于本课程教学实践中的体会,本文从课程教学中存在的问题及课堂教学的内容、方法和手段、实践环节等方面,提出了改革的思路,以期取得较好的效果。

To ensure main road traffic flow running smoothly, traffic volume condition for left-turn forbidden was analyzed. Defining equivalent people group to describe the non-motorized vehicles' and pedestrians' effect on vehicles, traffic flow priority of urban road unsignalized T-intersection was ranked renewedly, it was divided into five grades. Based on gap acceptance theory, potential capacity calculation models of each subordinate traffic flow were obtained. Taking prior traffic flow's effects on subordinate traffic flow into consideration, movement capacity models of subordinate traffic flows were established. Based on the analysis above, traffic volume condition for left-turn forbidden was got, namely, when the left-turn traffic volume is larger than the left-turn capacity, it is needed to taking left-turn forbidden. Case study indicates that the capacity calculation methods and traffic volume condition for left-turn forbidden are accord with the traffic flow running reality.

Aims at the issue of passenger turnover structure, based on Markov theory building the multi-product alternative forecast model, obtained the future passenger turnover structure under the stable state trend of transportation development. In practice this method has the strong feasibility, through the prediction of the passenger turnover this thesis could provide a viable research ideas for the harmonious order of passenger transport structure.

<正>随着我国交通事业的迅猛发展,各地区交通量的迅速增长,许多高速公路出现了交通拥挤、服务水平下降及事故频发等现象,形成诸多交通隐患,因而对高速公路进行改扩建的需求日趋强烈。对高速公路进行改扩建,在交通组织中既要高

Analysis the function of the queuing theory in highway charging system, in order to design and control the highway charging system reasonably, solve the cost antinomy which between the highway charging system and vehicles waiting for service, propitious to optimize resource collocate and save energy sources, and increase the economic and social benefit. This thesis discuss the application of optimum service rate in highway charging system, the object of optimize is to make the cost of the highway charging system and vehicles waiting for service minimum. First, we analysis the expense of optimum service rate in highway charging system, and then build up the queue model, educe high rank equation, make use of the MATLAB to draw a curve diagram, estimate the initial value, and use Newton iterative method, the result is the optimize service rate of the charging system, this method is very simple and accurate. Finally, we combine the specific instances to discuss the most economic and rational service rate in the queue of M/M/1/∞/∞/FCFS. The result shows that this method accords with the fact.

Water-specific aquaporins (AQP), such as the prototypical mammalian AQP1, stringently exclude the passage of solutes, ions, and even protons. Supposedly, this is accomplished by two conserved regions within the pore, a pair of canonical asparagine-proline-alanine (NPA) motifs, the central constriction, and an aromatic/arginine (ar/R) constriction, the outer constriction. Here, we analyzed the function of three residues in the ar/R constriction (Phe-56, His-180, and Arg-195) in rat AQP1. Individual or joint replacement of His-180 and Arg-195 by alanine and valine residues, respectively (AQP1-H180A, AQP1-R195V, and AQP1-H180A/R195V), did not affect water permeability. The double mutant AQP1-H180A/R195V allowed urea to pass. In line with the predicted solute discrimination by size, replacement of both Phe-56 and His-180 (AQP1-F56A/H180A) enlarged the maximal diameter of the ar/R constriction 3-fold and enabled glycerol and urea to pass. We further show that ammonia passes through all four AQP1 mutants, as determined (i) by growth complementation of yeast deletion strains with ammonia, (ii) by ammonia uptake from the external solution into oocytes, and (iii) by direct recordings of ammonia induced proton currents in oocytes. Unexpectedly, removal of the positive charge in the ar/R constriction in AQP1-R195V and AQP1-H180A/R195V appeared to allow the passage of protons through AQP1. The data indicate that the ar/R constriction is a major checkpoint for solute permeability, and that the exquisite electrostatic proton barrier in AQPs comprises both the NPA constriction as well as the ar/R constriction.

In this study the plane elasticity problem for a nonhomogeneous layer containing a crack perpendicular to the boundaries is considered. It is assumed that the Young’s modulus of the medium varies continuously in the thickness direction. The problem is solved under three different loading conditions, namely fixed grip, membrane loading, and bending applied to the layer away from the crack region. Mode I stress intensity factors are presented for embedded as well as edge cracks for various values of dimensionless parameters representing the size and the location of the crack and the material nonhomogeneity. Some sample results are also given for the crack-opening displacement and the stress distribution.

In this study an unconstrained elastic layer under statically self-equilibrating thermal or residual stresses is considered. The layer is assumed to be a functionally graded material (FGM), meaning that its thermo-mechanical properties are assumed to be continuous functions of the thickness coordinate. The layer contains an embedded or a surface crack perpendicular to its boundaries. Using superposition the problem is reduced to a perturbation problem in which the crack surface tractions are the only external forces. The dimensions, geometry, and loading conditions of the original problem are such that the perturbation problem may be approximated by a plane strain mode I crack problem for an infinite layer. After a general discussion of the thermal stress problem, the crack problem in the nonhomogeneous medium is formulated. With the application to graded coatings and interfacial zones in mind, the thickness variation of the thermo-mechanical properties is assumed to be monotonous. Thus, the functions such as Young's modulus, the thermal expansion coefficient, and thermal conductivity may be expressed by appropriate exponential functions through a two-parameter curve fit. The crack problem is reduced to art integral equation with a generalized Cauchy kernel and solved numerically. After giving some sample results regarding the distribution of thermal stresses, stress intensity factors for embedded and surface cracks are presented. Also included are the results for a crack/contact problem in a FGM layer that is under compression near and at the surface and tension in the interior region.

The primary objective of this paper is to study the influence of the structure and thickness of the interfacial regions on the strain energy release rate in bonded isotropic or orthotropic materials containing collinear interface cracks. The problem is formulated in terms of a system of singular integral equations of the second kind which is solved by using a relatively simple and efficient technique. A number of examples are given for various crack geometries and material combinations. The results show that the effect of the properties and the relative thickness of the interfacial region on the stress intensity factors and the strain energy release rate can be highly significant.

In this paper the plane strain problem for two bonded orthotropic layers containing a crack perpendicular to the laminate surfaces is considered. After deriving the integral equation for the general problem, the solution is obtained for three main crack geometries, namely an embedded crack, a surface crack and a crack terminating at the interface under a remotely applied membrane load or bending moment. For the crack terminating at the interface the necessary asymptotic analysis is carried out, the characteristic equation to determine the power of stress singularity β is obtained, and the influence of the material parameters on β is examined. The main results given in the paper consist of the stress intensity factors obtained for various crack geometries, material combinations and loading conditions.

In this paper the fracture mechanics of orthotropic materials containing collinear interface cracks is considered. The primary objective is to study the influence of the thickness and the structure of the interfacial regions on the crack driving force. The interfacial region is assumed to be a relatively thin orthotropic elastic layer. The stress intensity factors or the strain energy release rates are assumed to be the main measure of the crack driving force. A relatively simple and efficient method is presented to solve the related elasticity problem. The results are obtained for a wide range of actual material combinations. In order to study the influence of the structure of the interfacial zone, the problem is also solved for isotropic and orthotropic materials bonded through a layer with hypothetically selected material properties. The results show that the effect of the thickness, the mechanical properties and the material orientation of the interfacial zone on the strain energy release rate could be very significant. An interesting and a rather useful result obtained from the collinear crack solutions is that the strain energy release rates for multiple cracks in bonded orthotropic materials with or without an interfacial layer may be predicted by using the results obtained for an isotropic homogeneous plane provided that the normalization factors are selected properly.