CRTS, A Must-come Show

Some people said that the 5th CRTS [China International Rail Technology Show 2009] show is a remarkable event in the history of urban rail transit in China. It is not only because 2009 is the 60th anniversary of China＇s National Day, but also the 40th anniversary of China＇s subway construction. To sum up the achievements in forty years in urban rail transit construction, a series of themed activities, approved by Ministry of Housing and Urban-Rural Development of P.R.C. and guided by China Civil Engineering Society,     

走向国际轨道交通市场的上海城建

“As the bellwether in domestic rail transit market, Shanghai Urban Construction （Group） Corporation lights the way for Chinese enterprises of its kind to the outside world. Due to its strategic implementation in international market, it keeps the orientation of industrial development in its grasp and sets the trend for the industry. As a result, not only have earthshaking changes taken place in the corporation itself, but also k shows the achievements of Chinese enterprises. China＇s rail transit design and construction enterprises are striving to succeed overseas,there we concern.”     

Brief Introduction to Journal of Modern Transportation

China’s high-speed rail network expands dramatically and now stretches more than eightthousand kilometers.China owns a set of original high-speed rail technologies and has theadvantages in construction time and cost.Journal of Modern Transportation(JMT),the soletransportation-featuring English periodical in China with both CN and ISSN     

China＇s passenger railway construction in rapid progress

According to the news in Chinese Ministry of Railways website, the construction of Beijing-Shanghai,Wuhan-Guangzhou,Zhengzhou-Xi＇an, Ha＇erbin-Dalian railway and other passenger lines are in full swing. Facing the difficulties of high construction standards, great technology barriers and tight construction schedule, the railway sector stick together, keep boosting the construction in accordance with the ＂Six in One＂ requirements of quality, safety, schedule, investment efficiency, environmental protection and technological innovation, pursuing the objective of first-class engineering qualily, topgrade equipment level, first-rate operation management.     

Recent Advances in Radio Frequency Ablation Techniques of Atrial Fibrillation

Multiple wavelet hypothesis and fibrillatory conduction are believed to be atrial fibrillation＇s pathogenesis. Radio frequency ablation（RFA） technique, a therapy for atrial fibrillation（AF）, applies radio frequency（RF） energy to targeted tissue to make it transmural. Research on AF ablation has already been conducted in China. Currently, there are single-electrode and dual-electrode ablation electrodes. It is discovered that the latter can reduce the treatment time and maintain the ablation shape of the tissue. Clinical application has shown that it has become the first-line treatment option for part of indications patients with AF.     

Preface

High-speed rails （HSR） are playing an important role in the transportation systems across the world. In Japan, the Shinkansens carry more than 250 million passengers each year. In Europe, the trans-European high-speed rail network is in operation. At the beginning of 2011, U.S. President has called for a six-year, $53 billion budget for HSR. Nowadays, China has built the world＇s largest HSR network of over 4 600 miles.     

Evolution assessment of china’s three mega-city regions based on entire-array-polygon method

Mega-city region is the mainstream of global urban development and also the dominant model of the neo urbanization process in China. The Beijing-Tianjin-Hebei area, Yangtze River Delta area and Pearl River Delta area are China＇s three largest and most mature mega-city regions, the status of which represents the general level of the urban and regional development in China. Based on entire-array-polygon method, this paper makes a comprehensive evolution assessment of the three mega-city regions in terms of urban population index, urban economy index, urban life index, urban culture index and urban primacy index. In terms of general developing level, the three mega-city regions have progressed to optimize the structure. With their respective advantages and disadvantages, the three mega-city regions initially realize a ＂diversified＂ regional layout. The difference and gap among the three mega-city regions are obviously decreasing, which contributes to the regional balance of China metropolitan development. The rankings of the three mega-city regions will be in a continuous adjustment. The Beijing-Tianjin-Hebei area is possible to catch up and take the lead.     

A PARALLEL SWITCH FABRIC BASED ON CROSSBAR

With the increase of link rate, the arbitrator of centralized switch fabric becomes too complicated to implement. A parallel switch fabric based on crossbar, named as PSFBC （Parallel Switch Fabric Based on Crossbar）, has been proposed in this paper. PSFBC is composed of k switches whose rate is 1/k of link, these switches exchange cells in parallel; this increases the arbitrator＇s period and make it easy to implement. Load is evenly distributed to each switch with FCFS （First Come First Serve） rule, it can keep the order of cells in one stream. A multi-class queue scheduling policy is used in PSFBC to ensure the quality of realtime streams. Experiments show that the load on each switch in PSFBC is well balanced, its average delay of cells is little and its performance is very close to centralized switch; and with the increase of number of parallel switches, the loss of PSFBC＇s performance keeps very small, it becomes easier to implement.     

Dynamic model of underwater snake-like robot using Kane’s method

In this paper, a dynamic model for an underwater snake-like robot is developed based on Kane＇s dynamic equations. This methodology allows construction of the dynamic model simply and incrementally. The partial velocity is deduced. The forces which contribute to dynamics are determined by Kane＇s approach. The generalized active forces and the generalized inertia forces are deduced. The model developed in this paper includes inertia force, inertia moment, gravity, control torques, and three major hydrodynamic forces： added mass, profile drag and buoyancy. The equations of hydrodynamic forces are deduced. Kane＇s method provides a direct approach for incorporating external environmental forces into the model. The dynamic model developed in this paper is obtained in a closed form which is well suited for control purposes. It is also computationally efficient and has physical insight into what forces really influence the system dynamics. The simulation result shows that the proposed method is feasible.     

Multiple mental tasks classification based on nonlinear parameter of mean period using support vector machines

Mental tusk classification is one of the most important problems in Brain-computer interface. This paper studies the classification of five-class mental tusks. The nonlinear parameter of mean period obtained from frequency domain information was used as features for classification implemented by using the method of SVM （support vector machines）. The averaged classification accuracy of 85. 6% over 7 subjects was achieved for 2-second EEG segments. And the results for EEG segments of 0.5s and 5.0s compared favorably to those of Garrett＇s. The results indicate that the parameter of mean period represents mental tusks well for classification, Furthermore, the method of mean period is less computationally demanding, which indicates its potential use for online BCI systems.     

Computational method for prestress developing of tensile cable-net structures

The prestress developing of tensile cable-net structures is a state transforming process from the initial unstressed state to the final prestressed state, and it is rather complicated because the elastic deformation is normally coupled with the kinematic mechanism movement. Firstly, the basic equations of prestress developing by moving boundary joint are derived from the total potential energy equation. Secondly, the presumed initial tension is proposed to impose into the elements and avoid the singularity of global stiffness matrix. And the self-stress mode which is calculated from the equilibrium matrix with singular value decomposition is employed as basically presumed initial tension. By applying boundary movement increment, an iterative computation is developed to calculate the updating geometric configuration and tension evolution. Finally, the MATLAB program is coded from the presented method, and numerical examples indicate that this computational method is effective and has theoretical significance and valuable guide to design and construction of tensile cable-net structure.     

Design of rail pressure tracking controller for novel fuel injection system

This paper proposes a rail pressure tracking controller based on a novel common rail system. A mathematical model, based on physical equations, is developed and used for feed forward control design. Rail pressure peak sampling mechanism is designed to remove the disturbance of rail pressure due to fuel injection. An enhanced tracking differentiator is designed to get smooth tracking signal and exact differential signal from signal with noise. Double loop control strategy is designed to decouple the system and to improve dynamic performance of the system. Experimental results indicate that fluctuation of rail pressure is within ±1 MPa in steady condition, while within ±3 MPa in transient condition, which verifies the effectiveness of the proposed rail pressure control strategy.     

An enhanced safe distance car-following model

Gipps＇ model, a well-known safe distance car-following model, has a very strict restriction on the car-following behavior that the following vehicle has to maintain the exact safe distance to the leading vehicle to avoid rear crash. However, this restriction is not consistent with the real traffic condition. Due to that, an enhanced safe distance car-following model is proposed first, and then calibrated and evaluated using the field data. Furthermore, the simulation is conducted to analyze the characteristics of the new model. The results of evaluation and simulation illustrate that the proposed model has higher simulation accuracy than the original Gipps＇ model, and can reproduce the stable flow and shock wave phenomena that are very common in real traffic. Moreover, the simulation results also prove that the enhanced model can better stabilize the traffic flow than Gipps＇ model.     

Southwest Jiaotong University to Build a ＂National Rail Transit Laboratory＂

In the morning of May 5, the world＇s first high-speed railway built in collapsible loess region, Zhengzhou-Xi＇an Passenger Dedicated Line Shaanxi Section formally entered into track-laying stage, In Lintong working site, two 500-meterlong and 30-ton-weigh rail was successful laid on unballasted track after careful testing, marking the initiation of track-laying stage,     

Influence of Angle of Attack and Lateral Force between Wheel and Rail on Wear of Rail--a Laboratory Study

Angle of attack and lateral force are two important parameters influencing wheel-rail wear. This paper deals with the question of influences of the angle of attack and the lateral force on the wear of rail. A series of experiments are conducted on 1/4 JD-1 Wheel/Rail Tribology Simulation Facility. The angles of attack selected in the tests are 0°16′30″, 0°37′40″ and 1°0′0″ respectively. The lateral forces selected in the tests are 0.694 kN, 1.250 kN and 2.083 kN, respectively corresponding to the lateral forces of 25 kN, 45 kN and 75 kN measured in the field, with the aim of keeping the same ratio of L/V between laboratory and field conditions. It is found that the larger the angle of attack is, the more serious the wear of rail is. The relation of rail wear rate versus angle of attack is non-linear, and the relation of rail wear rate versus lateral force is approximately linear. The influence of angle of attack is more serious than that of lateral force. For the tractive wheelset, the wear index involving linear and quadratic function terms of angle of attack has good agreement with the limited experimental data. Some conclusions are given.     

Study of predicting breakdown voltage of stator insulation in generator based on BP neural network

The breakdown voltage plays an important role in evaluating residual life of stator insulation in generator. In this paper, we discussed BP neural network that was used to predict the breakdown voltage of stator insulation in generator of 300 MW/18 kV. At first the neural network has been trained by the samples that include the varieties of dielectric loss factor tan δ, the partial discharge parameters and breakdown voltage. Then we tried to predict the breakdown voltage of samples and stator insulations subjected to multi-stress aging by the trained neural network. We found that it＇s feasible and accurate to predict the voltage. This method can be applied to predict breakdown voltage of other generators which have the same insulation structure and material.     

Wavelet moment invariants extraction of underwater laser vision image

Wavelet moment invariants are constructed for object recognition based on the global feature and local feature of target, which are brought for the simple background of the underwater objects, complex structure, similar form etc. These invariant features realize the multi-dimension feature extraction of local topology and invariant transform. Considering translation and scale invariant characteristics were ignored by conventional wavelet moments, some improvements were done in this paper. The cubic B-spline wavelets which are optimally localized in space-frequency and close to the forms of Li＇s （or Zernike＇s） polynomial moments were applied for calculating the wavelet moments. To testify superiority of the wavelet moments mentioned in this paper, generalized regression neural network （GRNN） was used to calculate the recognition rates based on wavelet invariant moments and conventional invariant moments respectively. Wavelet moments obtained 100% recognition rate for every object and the conventional moments obtained less classification rate. The result shows that wavelet moment has the ability to identify many types of objects and is suitable for laser image recognition.     

Empirical Estimation of Term Structure of Interbank Rates in China

Nelson-Siegel model （ NS model） and 2 extended NS models were compared by using daily interbank government bond data Based on the grouping of bonds according to the residual term to maturity, the empirical research proceeded with in-sample and outof-sample tests. The results show that the 3 models are almost equivalent in estimating interbank term structure of interest rates. Within the term to maturities between 0 and 7 years, the gap of the absolute errors of the 3 models between in-sample and out-of-sample is smRller than 0.2 Yuan, and the absolute values of the in-sample and out-of-sample errors are smaller than 0. 1 Yuan, so the estimation is credible. Within the term to maturities between 7 and 20 years, the gap of the absolute errors of the 3 models between in-sample and out-of-sample is larger than 0.4 Yuan, and the absolute values of the in-sample and out-of-sample errors are larger than 1.0 Yuan, so the estimation is incredible.     

Leave the expressway or not？ Impact of dynamic information

This study investigates drivers＇ diversion decision behavior under expressway variable message signs that provide travel time of both an expressway route and a local street route. Both a conventional cross-sectional logit model and a mixed logit model are developed to model drivers＇ response to travel time information. It is based on the data collected from a stated preference survey in Shanghai, China. The mixed logit model captures the heterogeneity in the value of ＂travel time＂ and ＂number of traffic lights＂ and accounts for correlations among repeated choices of the same respondent. Results show that travel time saving and driving experience serve as positive factors, while the number of traffic lights on the arterial road, expressway use frequency, being a middle-aged driver, and being a driver of an employer-provided car serve as negative factors in diversion. The mixed logit model obviously outperforms the cross-sectional model in dealing with repeated choices and capturing heterogeneity regarding the goodness-of-fit criterion. The significance of standard deviations of random coefficients for travel time and number of traffic lights evidences the existence of hetero- geneity in the driver population. The findings of this study have implications for future efforts in driver behaviormodeling and advanced traveler information system assessment.     

Real-Time Method for Detecting Harmonic and Reactive Currents of Single-Phase Circuits

According to the characteristics of single-phase circuits and demand of using active filter for real-time detecting harmonic and reactive currents, a detecting method based on Fryze＇s power definition is proposed. The results of theoretical analysis and simula- tion show that the proposed method is effective in realtime detecting of instantaneous harmonic and reactive currents in single-phase circuits. When only detecting the total reactive currents, this method does not need a phase-locked loop circuit, and it also can be used in some special applications to provide different compensations on the ground of different requirements of electric network. Compared with the other methods based on the theory of instantaneous reactive power, this method is simple and easy to realize.