Developing Greenways Under a Top-Down Institutional Structure: A Case Study in the Pearl River Delta, China

Greenways are linear open spaces and networks of lands that are planned, designed and managed for ecological, scenic, recreational and cultural purposes (Little, 1990; Ahern, 1995; Fabos, 1995; Erickson, 2004; Jongman & Pungetti, 2004). Greenways are commonly structured by natural or humanmade features such as rivers, ridgelines, railroads, canals or roads (Erickson, 2004). In the international greenway movement, greenways no longer had only a beautification and recreational function, but expanded to multiple objectives, such as habitat protection, flood hazard reduction, water quality improvement, historical preservation, education and interpretation (Searns, 1995; Tan, 2006). Moreover, the concept of greenways shows high compatibility with diverse forms, which is “a route which is good from an environmental point of view” (Turner, 1998). In China, the modern greenway movement started in 2010, when Guangdong Provincial Government initiated a three-year political campaign to construct the Pearl River Delta (PRD) Greenway Network. In 2014, the PRD greenways had a total length of 8,909 kilometers, connecting all 46 districts/counties in the PRD metropolitan region. The PRD Greenway Network has been assumed to be a feasible and low-cost approach to tackling with Chinese urbanism issues. Consequently, it is becoming an influential model for the greenway development at the national scale. Eleven provinces in China have recently planned or implemented provincial greenways, and many cities are working on municipal greenways. The development of greenways is beginning to stimulate the growth of greenway literature in China. Most of existing studies focus on early efforts and visions of greenway functions and benefits based on western experiences (Yu, Li, & Li, 2006). However, there is a lack of comprehensive profile of the rapidly developed greenways. Therefore, this paper will review the forms, functions and qualities of greenways based on a series of case studies

Developing greenways under a top-down institutional structure: a case study in the Pearl River Delta, China

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Secure Indoor Localization Based on Extracting Trusted Fingerprint

Indoor localization based on WiFi has attracted a lot of research effort because of the widespread application of WiFi. Fingerprinting techniques have received much attention due to their simplicity and compatibility with existing hardware. However, existing fingerprinting localization algorithms may not resist abnormal received signal strength indication (RSSI), such as unexpected environmental changes, impaired access points (APs) or the introduction of new APs. Traditional fingerprinting algorithms do not consider the problem of new APs and impaired APs in the environment when using RSSI. In this paper, we propose a secure fingerprinting localization (SFL) method that is robust to variable environments, impaired APs and the introduction of new APs. In the offline phase, a voting mechanism and a fingerprint database update method are proposed. We use the mutual cooperation between reference anchor nodes to update the fingerprint database, which can reduce the interference caused by the user measurement data. We analyze the standard deviation of RSSI, mobilize the reference points in the database to vote on APs and then calculate the trust factors of APs based on the voting results. In the online phase, we first make a judgment about the new APs and the broken APs, then extract the secure fingerprints according to the trusted factors of APs and obtain the localization results by using the trusted fingerprints. In the experiment section, we demonstrate the proposed method and find that the proposed strategy can resist abnormal RSSI and can improve the localization accuracy effectively compared with the existing fingerprinting localization algorithms

UAV-Assisted Traffic Speed Prediction via Gray Relational Analysis and Deep Learning

Accurate traffic prediction is crucial to alleviating traffic congestion in cities. Existing physical sensor-based traffic data acquisition methods have high transmission costs, serious traffic information redundancy, and large calculation volumes for spatiotemporal data processing, thus making it difficult to ensure accuracy and real-time traffic prediction. With the increasing resolution of UAV imagery, the use of unmanned aerial vehicles (UAV) imagery to obtain traffic information has become a hot spot. Still, analyzing and predicting traffic status after extracting traffic information is neglected. We develop a framework for traffic speed extraction and prediction based on UAV imagery processing, which consists of two parts: a traffic information extraction module based on UAV imagery recognition and a traffic speed prediction module based on deep learning. First, we use deep learning methods to automate the extraction of road information, implement vehicle recognition using convolutional neural networks and calculate the average speed of road sections based on panchromatic and multispectral image matching to construct a traffic prediction dataset. Then, we propose an attention-enhanced traffic speed prediction module that considers the spatiotemporal characteristics of traffic data and increases the weights of key roads by extracting important fine-grained spatiotemporal features twice to improve the prediction accuracy of the target roads. Finally, we validate the effectiveness of the proposed method on real data. Compared with the baseline algorithm, our algorithm achieves the best prediction performance regarding accuracy and stability

Heterogeneous landscapes of urban greenways in Shenzhen: Traffic impact, corridor width and land use

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User, Public, and Professional Perceptions of the Greenways in the Pearl River Delta, China

The perception of greenways has been intensively investigated to understand the attitudes of stakeholders and to study the preferences of greenway users. In the Pearl River Delta, there has been a long-term debate on the form and function of greenways in campaign-style development, but few studies have focused on the public perception of greenways. Through both onsite and online investigations, this study obtained first-hand data about the user perceptions of greenways in selected case studies and developed an overall understanding of the public perception of the Pearl River Delta (PRD) greenways. Moreover, to examine the academic debate, we further distributed questionnaires to groups that had professional educational backgrounds related to greenway planning. The results showed that, in contrast with the academic debate, the user, public and professional perceptions were positive toward PRD greenways. Although it has been commonly recognized that bikeways compose the primary form of PRD greenways, the results suggested that the public has multiple needs for greenways, in which the primary demands are recreation and transportation. The investigation also identified many issues in greenway practices regarding the accessibility of greenway spaces, the coherence of nonmotorized routes, and the landscape characteristics of the greenways. Finally, this study suggests that more effort should be placed on the everyday demands of greenways, including accessible recreational resources and safe, comfortable, and coherent nonmotorized routes

Can greenways perform as a new planning strategy in the Pearl River Delta, China?

© 2019 The modern greenway movement in China originated in 2010 when Guangdong Provincial Government launched the Pearl River Delta greenway network. The PRD greenway planning has strategic objectives that respond to issues associated with urbanization in the region. This article presents a conceptual framework that explains the potential impact of several key factors in the planning context on the strategic uses of greenways. The framework is then applied to empirical research carried out in the PRD. The results show that greenway planning is a feasible strategy to promote rural economic development by attracting tourists and promoting the development of service sectors. In general, the PRD greenways function as a social strategy: they create new recreational spaces and provide public goods and facilities in both urban and rural areas. However, the results also show that many greenways lack landscape and ecological strategies and become primarily a transportation strategy that defines space for walking and cycling routes in urban areas. The emerging transportation-led greenways reflect the inconsistency of planning goals and outcomes, which is a compromise to both the centralized administrative system and the inadequacy of greenway resources. This article concludes that although strong leadership is necessary in greenway development, insufficient social participation can undermine the achievement of the goals and priorities of the greenway plan, particularly the ecological goals and functions. How to engage local agencies, interested groups, and affected stakeholders in the planning and decision-making process has become a big challenge for greenway planning in the PRD greenways.status: publishe

User, Public, and Professional Perceptions of the Greenways in the Pearl River Delta, China

status: publishe

Parameters Optimization and Test of Caterpillar Self-Propelled Tiger Nut Harvester Hoisting Device

Aiming at the problem of a poor separation of tiger nut, soil and grass during harvest, a hoisting device consisting of a combined-type hoisting sieve, vibrating wheels and soil roller was designed in combination with the requirements of the planting and harvesting of tiger nut. Through a theoretical analysis of the movement of the mixture of tiger nut, sand and grass in the process of hoisting, the basic law that affects the soil filter rate was determined, and the parameters affecting the soil-sieving rate were determined, and the hoisting angle, linear hoist speed and range of related parameters of vibrating wheels were obtained. Based on the DEM-MBD method, a simulation model of an excavating and hoisting device was built. With the hoisting angle, linear hoist speed, vibrating frequency and vibrating amplitudes of vibrating wheels as test factors, and the soil-sieving rate as test index, an orthogonal rotating-center combination test with four factors and three levels was carried out. The results showed that the influence of various factors on soil-sieving rate was as follows: vibrating frequency of vibrating wheels > linear hoist velocity > vibrating amplitudes of vibrating wheels > hoisting angle. When the vibrating frequency of the vibrating wheels was 9 Hz, the linear hoist speed was 0.66 m/s, vibrating amplitude of vibrating wheels was 25 mm and hoisting angle was 26°; the maximum value of the soil-sieving rate was 42.5%. The optimized parameters were applied to field test for verification, and the soil-sieving rate of the field test was 44.7%, which was better than the simulation test. The research results can provide a theoretical reference for design optimization and simulation analysis of tiger nut harvesters