Effective Caching of Shortest Travel-Time Paths for Web Mapping Mashup Systems

Author(s):  
Detian Zhang ◽  
An Liu ◽  
Gangyong Jia ◽  
Fei Chen ◽  
Qing Li ◽  
...  
Keyword(s):  
Author(s):  
Roger Lloret-Batlle ◽  
Neda Masoud ◽  
Daisik Nam

This paper presents a matching and pricing mechanism for a peer-to-peer ridesharing system that ensures a ride-back for matched riders. This service is thus presented as an alternative to driving alone for daily commuting. The matching algorithm is formulated as a minimum-cost, maximum-flow problem that is exact and quickly solvable on polynomial time. The mechanism modeling is based on the Vickrey–Clarke–Groves (VCG) mechanism that is known to be efficient, incentive compatible, and individually rational. However, VCG runs on a budget deficit in a ridesharing setting. To address this issue, participants were classified into drivers and riders in accordance with a novel multiparameter reserve price that fixes the revenue shortage problem and makes the system financially self-sustainable but in detriment of no longer being efficient. Agents’ utility functions include cost-sharing savings and high-occupancy-vehicle (HOV) travel time savings. The parametric study uses origin–destination demand data from the Southern California Association of Governments, and travel times are extracted from a professional web mapping service. Results show the method has a revenue surplus over most of the reserve-price parameter space and offers high matching rates attributable to the inclusion of HOV travel time savings and reserve-price structure. The reserve prices are drawn from empirical distributions of value of time and unit distance cost.


2019 ◽  
Vol 11 (4) ◽  
pp. 1160 ◽  
Author(s):  
Zhicheng Zheng ◽  
Haoming Xia ◽  
Shrinidhi Ambinakudige ◽  
Yaochen Qin ◽  
Yang Li ◽  
...  

The accessibility of hospital facilities is of great importance not only for maintaining social stability, but also for protecting the basic human right to health care. Traditional accessibility research often lacks consideration of the dynamic changes in transport costs and does not reflect the actual travel time of urban residents, which is critical to time-sensitive hospital services. To avoid these defects, this study considered the city of Kaifeng, China, as an empirical case, and directly acquired travel time data for two travel modes to the hospital in different time periods through web mapping API (Application Program Interface). Further, based on travel time calculations, we compared five baseline indicators. For the last indicator, we used the optimal weighted accessibility model to measure hospital accessibility for each residential area. The study discovered significant differences in the frequency and spatial distribution of hospital accessibility using public transit and self-driving modes of transportation. In addition, there is an imbalance between accessibility travel times in the study area and the number of arrivals at hospitals. In particular, different modes of transportation and different travel periods also have a certain impact on accessibility of medical treatment. The research results shed new light on the accessibility of urban public facilities and provide a scientific basis with which local governments can optimize the spatial structure of hospital resources.


2020 ◽  
Author(s):  
Chi Shen ◽  
Zhongliang Zhou ◽  
Sha Lai ◽  
Li Lu ◽  
Wanyue Dong ◽  
...  

Abstract Background: The Chinese government proposed the "XIAO BING BU CHU CUN, DA BING BU CHU XIAN” initiative in 2016, which states the rate of health care service provided by county hospitals should reach 90% of overall health care service provision. The prerequisite for achieving this goal is that citizens should be able to access county hospitals’ services conveniently and impartially. However, little research has been done on the actual levels of the spatial accessibility of citizens to county hospitals in Western China. Therefore, we aimed to measure the spatial accessibility to county hospitals for county residents and to identify any regional disparities in Shaanxi Province in Western China.Methods: We implemented a novel method – involving utilizing navigation data from the AutoNavi web mapping system (knows as Gaode map in Chinese) – to assess the time and distance from villages and neighborhoods to the county hospitals. The navigation data were collected by request through an application-programming-interface using a web crawler (web data extraction tool) in Python. The shortest driving time and distance were extracted from the navigation data. The travel impedance to the nearest provider (TINP) indicator was used to measure spatial accessibility. Results: The results show that county residents in Western China's Shaanxi Province have poor spatial accessibility to county hospitals. Only 68.8% of villages and neighborhoods are within 60 minutes travel time (based on driving mode) to a county hospital, while 13.4% of such villages and neighborhoods are beyond 90 minutes travel time. Moreover, a significant within-province disparity exists, with residents in the central area enjoying the best accessibility to county hospitals, while the northern and southern areas still need improvements in accessibility.Conclusions: Focused health resource planning is required to improve the spatial accessibility to county hospitals and to eliminate regional disparities. Further studies are called for to integrate the navigation data of web mapping systems with GIS methods to the measure spatial accessibility of health facilities in more complex contexts.


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