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With the application of machine learning rapidly gaining popularity in computer science and other fields, neural network techniques have successfully simulated the performance of in-service pavements as they are efficient in predicting and solving nonlinear relationships and in dealing with uncertain large-area pavement problems. In this paper, we address the problem of the optimal timing of preventive maintenance of asphalt pavements to accurately predict the condition index (pavement condition index, PCI) of highway asphalt pavements and develop a highly accurate, long-period, multifactor prediction model with the suitability of preventive maintenance at its core. The prediction model is called differential evolution particle swarm optimization back propagation (DEPSO-BP) neural network, and the input dimension of the prediction model is determined by gray correlation analysis (GCA), and DEPSO is used to improve the search efficiency of BP neural network and the asphalt pavement usage performance with parameter continuity prediction model. Finally, the Qinglan Highway (G22) PCI of Gansu Province, China, is selected for example validation, and the prediction results are compared with those of the four models. The results show that the multifactor prediction model based on DEPSO-BP neural network has good generalization ability. This model is important for improving the economic efficiency of road maintenance, and can be used in the long-cycle process to provide model reference and scientific basis for the subsequent road maintenance budget application and decision-making scheme. [ABSTRACT FROM AUTHOR]

Transfer between the metro (underground railway system) and buses is standard in many cities, and the simultaneous arrival of these two modes can provide passengers with a smoother transfer experience. However, previous synchronous transfer studies rarely consider different public transport modes simultaneously. This paper presents an optimization model that maximizes the number of metro and bus network synchronizations considering the connection level. An improved algorithm that combines simulated annealing (SA) and artificial bee colony (ABC) is proposed. The best nectar source position in history is combined with the SA operation. The ABC and simulated annealing and improved artificial bee colony (SA–IABC) algorithms are used to solve the model using the Nanmendou metro station and the bus stations within 1.2 km around it in Fuzhou City, China. The results show that ABC and improved SA–IABC algorithms increase the synchronization times of the metro and bus network by 17% and 24% on average, respectively, without expanding the departure frequency. [ABSTRACT FROM AUTHOR]

Work zones which are usually referred to as traffic bottlenecks or critical points may lead to reductions in both operational performance and safety. Researchers have conducted extensive studies on speed characteristics in freeway work zones. However, most of these studies are based on simulation data or are travel direction-based rather than lane-based. By utilizing the video recording capability of drones, this paper aims to provide methodologies and the workflow in exploring the vehicular speed characteristics in freeway work zones with considerations for lane and location deviations. A four-to-three lane work zone on Huhang Expressway between Downtown Shanghai and Songjiang in China was selected for data collection. Then free flow speed variation pattern is analyzed, a speed prediction model is proposed, and the speed–flow relationship is investigated on each lane at nine virtual sections along the work zone. It is found that the merging area affects the speeds mainly in the segment from 200 m upstream of the taper to the start of the activity area, which is the most important risk area in the work zone, and the speed characteristics depend on vehicle types (trucks versus automobiles) as well as lane locations. It is also showed that drones are valuable and effective tools for data collection for vehicular speed characteristics analysis in freeway work zones and it is easy to extract the information needed. [ABSTRACT FROM AUTHOR]

Limited by the low-frequency data acquisition, vehicle global positioning system (GPS) data are difficult to implement in the area of microtraffic simulation. Based on the functional design of mobile phone positioning technology, mobile phones can be used to acquire bus GPS data every second. In this paper, an analytical model is proposed to determine the parameters of signal coordination for bus priority along an arterial based on GPS data of mobile phones. First, bus priority evaluation indicators are established using bus GPS data, which are acquired by mobile phones. Second, the signal timing parameters of the arterial road are optimized, and a preliminary timing plan is developed by evaluating small changes in the plan. Finally, the corresponding final plan is developed using VISSIM micro simulation software. The feasibility of the analytical model is verified by simulating an actual arterial in Fuzhou city, China. [ABSTRACT FROM AUTHOR]

Light emitting diode (LED) traffic signs have been deployed on many urban roadways recently. However, a lack of uniform engineering criteria for the luminance level of LED traffic signs in China brought up consequences such as inaccurate recognition of signs for drivers as well as potential traffic accidents. This paper explores the possible luminance range of LED traffic signs through full-scale field static experiments. Visual recognition distance, character height, character stroke, sign background color, sign dimension, and sign complexity degree are taken into account. The visual recognition luminance value required for drivers are recorded. Experiment results reveal that: for character symbol, the background color of the board and character strokes have no significant effect on driver's visual recognition performance; for graphic symbol, the higher of graphic complex degree, the higher luminance value required for driver to recognize. This study summarizes the luminance thresholds of different kinds of LED signs for different roadway classes. The findings of this study would provide reference for future design of LED traffic signs. [ABSTRACT FROM AUTHOR]

Beijing is located in a semiarid region, and water shortage is a common problem in the city. Along with the rapid increase in water demand, due to fast socioeconomic development and an increase in population, a shortage of water resources and a deterioration of the water environment have become obstacles to sustainable socioeconomic development in Beijing. In the long run, sustainable water resources management, water conservation, and completion of the south to north water diversion project will solve the problem. This paper introduces the water resources situation in Beijing; analyzes future water demand; and discusses the actions of water saving, nontraditional water resources exploitation, wetland construction, and water environment protection. The paper also explains the importance of the south to north water diversion project and the general layout of the water supply strategy, water distribution system, and methods to efficiently use the diverted water in Beijing. [ABSTRACT FROM AUTHOR]

Reflective cracking distresses frequently occur on the hot mix asphalt (HMA) overlay due to the movements of the underlying Portland cement concrete (PCC). Rubblization was proven in North America to be an effective approach among slab fracturing technologies for solving the premature reflective cracking problem. This paper presents the procedure of applying the rubblization technology in HMA overlay design in a research effort in China to develop the Chinese standard. In the study, the validity of rubblization was analyzed by a trench survey and sieve tests; the layer moduli of the composite subgrade and rubblized concrete slab were determined using FWD and plate bearing tests and a conversion chart; the thickness design for the HMA overlay over the rubblized PCC pavement was conducted using a Chinese version mechanistic-empirical design process; and finally the in-service monitoring over the pavements built using the developed procedure was conducted to test the validity of the procedure. [ABSTRACT FROM AUTHOR]

By integrating the vehicle tracking system, discrete-event simulation algorithm, and evolutionary optimization algorithm, we developed HKCONSIM-Realtime, a decision-support platform created specifically for handling ready-mixed concrete operations. This platform is capable of (1) tracking the positions of concrete trucks and monitoring the motion and status of concrete deliveries in real time, (2) transforming the tracking records into data that provide updated input to simulation, and (3) optimizing the operations and logistics of concrete production based on simulation of the production system using the most current data. This paper presents an overview of the design and development of (1) the hardware and software modules, (2) the data flow and processing throughout the system, and (3) the role of the system in providing interactive, effective support for the human operator to attain cost efficiency. Case studies are given to demonstrate the functionality and application of the prototype system. [ABSTRACT FROM AUTHOR]

This paper illustrates the importance of river ice accumulations in changing river channel geometry based on field investigations carried out at the Hequ gauging station on the Yellow River in China. A relationship is established between riverbed deformation and ice accumulation. [ABSTRACT FROM AUTHOR]