Progress in high-speed train technology around the world

This is a review of high-speed train development in the sense of technology advances all over the world. Three generations of high-speed trains are classified according to their technical characteristics and maximum operating speed. Emphasis is given to the newly developed high-speed train in China, CRH380. The theoretical foundations and future development of CRH380 are briefly discussed.

Application of artificial neural networks for operating speed prediction at horizontal curves: a case study in Egypt

Horizontal alignment greatly affects the speedof vehicles at rural roads. Therefore, it is necessary toanalyze and predict vehicles speed on curve sections.Numerous studies took rural two-lane as research subjectsand provided models for predicting operating speeds.However, less attention has been paid to multi-lane highwaysespecially in Egypt. In this research, field operatingspeed data of both cars and trucks on 78 curve sections offour multi-lane highways is collected. With the data, correlationbetween operating speed （V85） and alignment isanalyzed. The paper includes two separate relevant analyses.The first analysis uses the regression models toinvestigate the relationships between V85 as dependentvariable, and horizontal alignment and roadway factors asindependent variables. This analysis proposes two predictingmodels for cars and trucks. The second analysisuses the artificial neural networks （ANNs） to explore theprevious relationships. It is found that the ANN modelinggives the best prediction model. The most influential variableon V85 for cars is the radius of curve. Also, for V85 fortrucks, the most influential variable is the median width.Finally, the derived models have statistics within theacceptable regions and they are conceptually reasonable.

Design Strategy of Highway Speed Transition Section

In this paper,combined with the relevant speed theory and characteristics of the law,the current highway speed transition design problems are studied and analyzed.In the process of specific analysis,mainly combined with the characteristics of different types of highway speed changes and road section design requirements,this paper studies and analyzes the design methods of different types of highway speed transition section.And on this basis,according to the design principles and requirements of highway operation speed transition section,the paper summarizes the matters needing attention in the design of highway operation speed transition section,in order to provide certain reference value for relevant personnel.

Speeding Up the Transformation of the Operational Mechanism And Further Developing the International Market

According to customs statistics, China’s exports of machinery and electric products in 1996 were worth US$ 48.21 billion, an increase of 9.9 percent over the preceding year, and 8.4 percent higher than the growth rate of the nation’s total exports. The proportion of machinery and electric product exports in the nation’s total foreign trade volume\ increased from 29.5 percent in 1995 to 31.9 percent in 1996, a growth at 2.4 percent.

The Effect of the Operational Parameters on the Draft Requirement of Ripping in a Sandy Clay Soil

This study set out to investigate the effect of operational parameters (i.e. ripping depth and operational speed) during a ripping operation on the draft requirement during ripping in a sandy-clay soil. Field experiments, laboratory tests and numerical modelling techniques were utilised to observe how the draft force varied with changing values of the operational parameters. The discrete element method in the EDEM AcademicTM software platform was employed to model the soil en-masse to obtain a virtual experimentation platform on which different treatments combing different settings of the operational parameters were investigated. Statistical methods, including ANOVA, regression analysis and the student t-test were applied to establish the significance of the effect of the operational parameters on the draft requirement;statistical analysis revealed that the draft increased linearly with the ripping depth and operating speed suggesting that they are directly proportional. Lower values of the ripping depth and operating speed were found to give the minimum amount of the draft requirement.

A Review of Sensorless Control Methods for AC Motor Drives

In recent years,the application of sensorless AC motor drives is expanding in areas ranging from industrial applications to household electrical appliances.As is well known,the advantages of sensorless motor drives include lower cost,increased reliability,reduced hardware complexity,better noise immunity,and less maintenance requirements.With the development of modern industrial automation,more advanced sensorless control strategies are needed to meet the requirements of applications.For sensorless motor drives at low-and zero-speed operation,inverter nonlinearities and motor parameter variation have significant impact on the stability of control system.Meanwhile,high observer’s bandwidth is required in high-speed region.This paper introduces the state of art of recent progress in sensorless AC motor drives.In addition,this paper presents the sensorless control strategies we investigated for practical industrial and household applications.Both advanced sensorless drives of induction motor(IM)and permanent magnet synchronous motor(PMSM)are presented in this paper.

Analyses of maximum-speed path definition at single-lane roundabouts

The process of designing roundabouts is an iterative process through which, in several checks, the design elements of a roundabout get optimized. Existing regulations for roundabouts involve swept path analyses, sight distance analyses and speed analyses of vehicles passing through the roundabout. Speed analyses are done mostly based on two models, Dutch and American. Each of these two models, in their own way takes into account design elements of the roundabouts, and the US model also envisions the construction of vehicle paths through the roundabout. Main assumption of both models is that vehicle paths through roundabouts consist of few connected radii. US models for path definition takes into account safety distances from marked lines and geometric elements（curbs） at the entrance and exit and through roundabout. Experimentally determined elements of the vehicle path through the roundabout, do not correspond to those recommendations. Comparison of the measured speed at the roundabouts and speed calculated according to aforementioned models at several roundabouts in Croatia, showed a significant difference. An experimental research was conducted as a first step in developing a new model for operating speed through roundabouts. The research aimed to define the basic path elements of vehicle movement in the roundabout at which the maximum speed is achieved. Results of the study are presented in this paper.

Size Reduction of Tunable Micromachined Filters for High Speed Operations

The size reduction of tunable micromachined filters is carried out for high-speed wavelength tuning. We fabricated micromachined filters having a miniature structure with an air gap of 300 run and a short cantilever of 45 urn, exhibiting fast response of below 3 us.

Beijing department stores speed up the development of chain operation

As the capital regional consumer market enhanced, a growing number of department stores ,supermarkets chose chain operating mode. ey occupy market by chain operation. At present, "Multi combination + differentiated management " has become a effective commercial expansion path of development. According to reporter statistics, including the Parkson shopping center, Guiyou Plaza, Blue Island, Cuiwei Plaza, Xidan shopping mall, Dangdai shopping mall , Wangfujing department store ,

Impact of combined alignments and adverse weather conditions on vehicle skidding

Roadways in Wyoming are characterized by challenging horizontal profiles,vertical profiles,a combination of the two and adverse weather conditions,all of which affect vehicle stability.In this study,we investigated the impact of different operating speeds when negotiating combined horizontal and vertical curves under unfavorable environmental conditions on Wyoming’s interstates via vehicle dynamics simulation software.The simulation tools provided the acting forces on each tire of the vehicle and the side friction(skidding)margins.This allowed for examining the interaction between vehicle dynamics and road geometry in such alignments.Also,linear regression analysis was implemented to investigate the skidding margins based on the simulation results to demonstrate when a vehicle is more likely to deviate from its desired trajectory.Specifically,this examines the contributing factors that significantly influence the skidding margins.The results indicated that:1)the skidding margins are dramatically decreased by adverse weather conditions even with lower degree of curvature and gradient values of combined curves and more particularly at higher operating speeds conditions.Increasing the vehicle speed on the curve by 10%,the skidding margin dropped by 15%.2)Compared to heavy trucks and sports utility vehicles(SUVs),passenger cars require the highest side friction demand.3)The effect of applying brakes on vehicle stability depends on the road surface condition;applying the brakes on snowy road surfaces increases the potential of vehicle skidding especially for heavy trucks.This study assessed the curve speed limits and showed how important to assign safe and appropriate limits speed since the skidding likelihood is significantly sensitive to the vehicle speeds.This study is beneficial to Wyoming’s roadway agencies since hazardous sections having combined horizontal and vertical curves are identified.Also,critical situations that require additional attention from law enforcement agencies are pinpointed.Finally,recommendations that are valuable to roadway agencies are made based on this study’s findings.

Experimental analysis of operational data for roundabouts through advanced image processing

Roundabout is still the focus of several investigations due to the relevant number of variables affecting their operational performances(i.e.,capacity,safety,emissions).To develop reliable models,investigations should be supported by devices and relate d sensors to extract variables of interest(i.e.,flow,speed,gap,lag,follow-up time,vehicle classification and trajectory).Notwithstanding that several sensors and technolo gies are currently used for data collection,most of them present limitations.The paper presents the investigation carried out to survey vehicle movem ents at roundabouts as a comprehensive video image analysis system is able to derive the origin/destination(O/D)matrix,compile a vehicle classification,track individual vehicle trajectories together with corresponding speeds and accelerations along paths.To this end,the authors collected video-sequences that were analysed with a piece of software developed for that task.To minimize the problems due to perspective distortion,environmental effects,and obstructions,a number of camera set-up configurations were adopted with equipment being placed on central or external poles,and on permanent fixtures such as raised working platforms outside the confines of the intersection area.Performance of those installation set-ups with different vehicle tracking strategies has been evaluated.Particularly,speed has been successfully related to trajectory tortuosity,the result of which emphasizes the tremendous potential of image analysis and opens up to further studies on the evaluation of the operational effects of roundabout geometrics.

Dynamic parameters of vehicles under heterogeneous traffic stream with non-lane discipline:An experimental study

On the heterogeneous and no lane disciplined traffic, the abreast maneuver of vehicles depends upon the driver behavior, vehicle type and most importantly the traffic parameters such as vehicle speed and acceleration. Hence, the drivers have two basic tasks while driving, first is to control the vehicle＇s position along longitudinal direction of motion and second is to control the vehicle＇s position along lateral direction i.e. the width of the roadway. The relation between the dynamic parameters （speed and lateral/longitudinal acceleration）, can very well represent the driving behavior of vehicles in mixed with weak or no lane disciplined traffic. Hence, the study of longitudinal and lateral control of vehicles in a comprehensive manner is necessary. In the present paper, driving behavior of vehicles are studied by analyzing longitudinal and lateral acceleration/deceleration （A/D） with operating speed of vehicles on different straight roadway sections. Data are collected from five major cities of India using GPS based instrument （Video-VBOX） mounted on five different type of vehicles. The probability distribution of longitudinal A/D and the lateral acceleration are analysed, and their relationship with operating speed of vehicles are studied on roads with a different number of lanes for different vehicle types. A two-term exponential and linear relationship with operating speed are observed for lateral and longitudinal A/D respectively.