This article presents a comprehensive framework for determining the location of road weather information system （RWIS） stations over a regional road network. In the proposed methodology, the region is divided into a...This article presents a comprehensive framework for determining the location of road weather information system （RWIS） stations over a regional road network. In the proposed methodology, the region is divided into a grid of equal-sized zones which are considered as the minimum spatial unit for allocating a candidate set of RWIS stations. These zones are ranked according to a set of pre-specified criteria that reflect the needs for, and potential benefits from, real-time RWIS, including road surface temperature variability, precipitation, network traffic, and collision patterns. A case study based on the existing RWIS network in the province of Ontario was conducted to illustrate the major features of the proposed method and evaluate the implications of alternative loca- tion selection criteria. The findings of the study suggest that it is feasible to develop a systematic process for locating RWIS stations using an integrated location criterion to capture multiple factors being considered in prac- tice. The study has also revealed the need to establish quantitative models for estimating the benefit of real-time information from RWIS stations, which is the foundation of a cost-benefit-based RWIS location optimization model.展开更多
In this research we proposed a strategy for location privacy protection which addresses the issues related with existing location privacy protection techniques. Mix-Zones and pseudonyms are considered as the basic bui...In this research we proposed a strategy for location privacy protection which addresses the issues related with existing location privacy protection techniques. Mix-Zones and pseudonyms are considered as the basic building blocks for location privacy; however, continuously changing pseudonyms process at multiple locations can enhance user privacy. It has been revealed that changing pseudonym at improper time and location may threat to user's privacy. Moreover, certain methods related to pseudonym change have been proposed to attain desirable location privacy and most of these solutions are based upon velocity, GPS position and direction of angle. We analyzed existing methods related to location privacy with mix zones, such as RPCLP, EPCS and MODP, where it has been observed that these methods are not adequate to attain desired level of location privacy and suffered from large number of pseudonym changes. By analyzing limitations of existing methods, we proposed Dynamic Pseudonym based multiple mix zone(DPMM) technique, which ensures highest level of accuracy and privacy. We simulate our data by using SUMO application and analysis results has revealed that DPMM outperformed existing pseudonym change techniques and achieved better results in terms of acquiring high privacy with small number of pseudonym change.展开更多
A safety management system was established to provide for continuously improved safety levels of the non-urban roads in Israel. One of the main functions of the system lies in the identification and treatment of HL （...A safety management system was established to provide for continuously improved safety levels of the non-urban roads in Israel. One of the main functions of the system lies in the identification and treatment of HL （hazardous locations） on existing roads. In line with the state-of-the art in road safety, the HL identification is based on an empirical Bayes evaluation, where an HL is recognized using a high positive difference between the number of accidents expected at the site and that predicted for similar sites. The latter is estimated using safety performance functions that were developed for local conditions, including single- and dual-carriageway road sections, and various types of intersections： signalized/non-signalized, three- and four-legged. The procedure of HL identification is applied annually, serving as a basis for the working programs on road infrastructure improvements. Positive safety effects of such improvements were recently reported in the country. These activities comply with the Road Infrastructure Safety Directive that was recently introduced in the European Union.展开更多
Location advantages of ports refer to the current developments of ports based on their conditions, such as geographic location, traffic accessibility and hinterland economy, etc., and the spatial pattern of ports’ lo...Location advantages of ports refer to the current developments of ports based on their conditions, such as geographic location, traffic accessibility and hinterland economy, etc., and the spatial pattern of ports’ location advantages reflects the spatial distributions, the regularities and the correlations among their conditions for development. A good understanding of the spatial patterns of ports’ location advantages can help to better identify the relative advantages of ports, position ports’ functions and make strategic plans for development. This paper selected 1259 ports from 63 countries along the Maritime Silk Road as research objects and builds an accessing model to analyze their location advantages on the bases of six factors: the influence of strategic shipping pivot, the competitiveness of port location potential, port network status, the influence of city, the influence of traffic trunk, and road network density in hinterland. The study has the following three findings. Firstly, the location advantages of ports show a 'high-low-high' distribution pattern from the west to the east, displaying an obvious 'core-periphery' regionalized distribution. Secondly, most ports have high location advantages, mainly located in Strait of Malacca, the United Arab Emirates, northern Mediterranean coastal region and China-Japan region, the top 10 ports are mainly located in Singapore, China, Malaysia and Japan, indicating that the shipping industry in Asia-Pacific region has stepped to the far front of the global competition;slow economic growths, wars, far away from the Belt and Road countries or bad climate have low location advantages, mainly located in African coastal areas, Oceania, Northeast Europe and Russia. Thirdly, compared with the landward location advantages, the seaward location advantages have a higher influence, and different indicators of location advantages have different influences on the evaluation results, the competitiveness of port location potential being the core indicator.展开更多
基金funded by the Aurora Programfunded by National Sciences and Engineering Research Council of Canada (NSERC)Ontario Ministry of Transportation (MTO)
文摘This article presents a comprehensive framework for determining the location of road weather information system （RWIS） stations over a regional road network. In the proposed methodology, the region is divided into a grid of equal-sized zones which are considered as the minimum spatial unit for allocating a candidate set of RWIS stations. These zones are ranked according to a set of pre-specified criteria that reflect the needs for, and potential benefits from, real-time RWIS, including road surface temperature variability, precipitation, network traffic, and collision patterns. A case study based on the existing RWIS network in the province of Ontario was conducted to illustrate the major features of the proposed method and evaluate the implications of alternative loca- tion selection criteria. The findings of the study suggest that it is feasible to develop a systematic process for locating RWIS stations using an integrated location criterion to capture multiple factors being considered in prac- tice. The study has also revealed the need to establish quantitative models for estimating the benefit of real-time information from RWIS stations, which is the foundation of a cost-benefit-based RWIS location optimization model.
基金supported by the National Natural Science Foundation of China (Grant No.61401040,Grant No.61372110)
文摘In this research we proposed a strategy for location privacy protection which addresses the issues related with existing location privacy protection techniques. Mix-Zones and pseudonyms are considered as the basic building blocks for location privacy; however, continuously changing pseudonyms process at multiple locations can enhance user privacy. It has been revealed that changing pseudonym at improper time and location may threat to user's privacy. Moreover, certain methods related to pseudonym change have been proposed to attain desirable location privacy and most of these solutions are based upon velocity, GPS position and direction of angle. We analyzed existing methods related to location privacy with mix zones, such as RPCLP, EPCS and MODP, where it has been observed that these methods are not adequate to attain desired level of location privacy and suffered from large number of pseudonym changes. By analyzing limitations of existing methods, we proposed Dynamic Pseudonym based multiple mix zone(DPMM) technique, which ensures highest level of accuracy and privacy. We simulate our data by using SUMO application and analysis results has revealed that DPMM outperformed existing pseudonym change techniques and achieved better results in terms of acquiring high privacy with small number of pseudonym change.
文摘A safety management system was established to provide for continuously improved safety levels of the non-urban roads in Israel. One of the main functions of the system lies in the identification and treatment of HL （hazardous locations） on existing roads. In line with the state-of-the art in road safety, the HL identification is based on an empirical Bayes evaluation, where an HL is recognized using a high positive difference between the number of accidents expected at the site and that predicted for similar sites. The latter is estimated using safety performance functions that were developed for local conditions, including single- and dual-carriageway road sections, and various types of intersections： signalized/non-signalized, three- and four-legged. The procedure of HL identification is applied annually, serving as a basis for the working programs on road infrastructure improvements. Positive safety effects of such improvements were recently reported in the country. These activities comply with the Road Infrastructure Safety Directive that was recently introduced in the European Union.
基金Major Program of National Social Science Fund of China,No.20&ZD070。
文摘Location advantages of ports refer to the current developments of ports based on their conditions, such as geographic location, traffic accessibility and hinterland economy, etc., and the spatial pattern of ports’ location advantages reflects the spatial distributions, the regularities and the correlations among their conditions for development. A good understanding of the spatial patterns of ports’ location advantages can help to better identify the relative advantages of ports, position ports’ functions and make strategic plans for development. This paper selected 1259 ports from 63 countries along the Maritime Silk Road as research objects and builds an accessing model to analyze their location advantages on the bases of six factors: the influence of strategic shipping pivot, the competitiveness of port location potential, port network status, the influence of city, the influence of traffic trunk, and road network density in hinterland. The study has the following three findings. Firstly, the location advantages of ports show a 'high-low-high' distribution pattern from the west to the east, displaying an obvious 'core-periphery' regionalized distribution. Secondly, most ports have high location advantages, mainly located in Strait of Malacca, the United Arab Emirates, northern Mediterranean coastal region and China-Japan region, the top 10 ports are mainly located in Singapore, China, Malaysia and Japan, indicating that the shipping industry in Asia-Pacific region has stepped to the far front of the global competition;slow economic growths, wars, far away from the Belt and Road countries or bad climate have low location advantages, mainly located in African coastal areas, Oceania, Northeast Europe and Russia. Thirdly, compared with the landward location advantages, the seaward location advantages have a higher influence, and different indicators of location advantages have different influences on the evaluation results, the competitiveness of port location potential being the core indicator.
文摘动态路网k近邻(kNN)查询是许多基于位置的服务(LBS)中的一个重要问题。针对该问题,提出一种面向动态路网的移动对象分布式kNN查询算法DkNN(Distributed kNN)。首先,将整个路网划分为部署于集群中不同节点中的多个子图;其次,通过并行地搜索查询范围所涉及的子图得到精确的kNN结果;最后,优化查询的搜索过程,引入查询范围剪枝策略和查询终止策略。在4个道路网络数据集上与3种基线算法进行了充分对比和验证。实验结果显示,与TEN~*-Index(Tree dEcomposition based kNN~*Index)算法相比,DkNN算法的查询时间减少了56.8%,路网更新时间降低了3个数量级。DkNN算法可以快速响应动态路网中的kNN查询请求,且在处理路网更新时具有较低的更新成本。
