A Safe-Region Approach to a Moving k-RNN Queries in a Directed Road Network

2017 ◽  
Vol 26 (05) ◽  
pp. 1750071 ◽  
Author(s):  
Kamil Zeberga ◽  
Rize Jin ◽  
Hyung-Ju Cho ◽  
Tae-Sun Chung

In road networks, [Formula: see text]-range nearest neighbor ([Formula: see text]-RNN) queries locate the [Formula: see text]-closest neighbors for every point on the road segments, within a given query region defined by the user, based on the network distance. This is an important task because the user's location information may be inaccurate; furthermore, users may be unwilling to reveal their exact location for privacy reasons. Therefore, under this type of specific situation, the server returns candidate objects for every point on the road segments and the client evaluates and chooses exact [Formula: see text] nearest objects from the candidate objects. Evaluating the query results at each timestamp to keep the freshness of the query answer, while the query object is moving, will create significant computation burden for the client. We therefore propose an efficient approach called a safe-region-based approach (SRA) for computing a safe segment region and the safe exit points of a moving nearest neighbor (NN) query in a road network. SRA avoids evaluation of candidate answers returned by the location-based server since it will have high computation cost in the query side. Additionally, we applied SRA for a directed road network, where each road network has a particular orientation and the network distances are not symmetric. Our experimental results demonstrate that SRA significantly outperforms a conventional solution in terms of both computational and communication costs.

2020 ◽  
pp. 002252662097950
Author(s):  
Fredrik Bertilsson

This article contributes to the research on the expansion of the Swedish post-war road network by illuminating the role of tourism in addition to political and industrial agendas. Specifically, it examines the “conceptual construction” of the Blue Highway, which currently stretches from the Atlantic Coast of Norway, traverses through Sweden and Finland, and enters into Russia. The focus is on Swedish governmental reports and national press between the 1950s and the 1970s. The article identifies three overlapping meanings attached to the Blue Highway: a political agenda of improving the relationships between the Nordic countries, industrial interests, and tourism. Political ambitions of Nordic community building were clearly pronounced at the onset of the project. Industrial actors depended on the road for the building of power plants and dams. The road became gradually more connected with the view of tourism as the motor of regional development.


2021 ◽  
Vol 43 (2) ◽  
pp. 262-278
Author(s):  
Ariane Dupont-Kieffer ◽  
Sylvie Rivot ◽  
Jean-Loup Madre

The golden age of road demand modeling began in the 1950s and flourished in the 1960s in the face of major road construction needs. These macro models, as well as the econometrics and the data to be processed, were provided mainly by engineers. A division of tasks can be observed between the engineers in charge of estimating the flows within the network and the transport economists in charge of managing these flows once they are on the road network. Yet the inability to explain their decision-making processes and individual drives gave some room to economists to introduce economic analysis, so as to better understand individual or collective decisions between transport alternatives. Economists, in particular Daniel McFadden, began to offer methods to improve the measure of utility linked to transport and to inform the engineering approach. This paper explores the challenges to the boundaries between economics and engineering in road demand analysis.


Author(s):  
R. S. Durov ◽  
◽  
E. V. Varnakova ◽  
K. O. Kobzev ◽  
◽  
...  

Introduction. One of the most pressing socio-economic problems is the state of the environment, which affects the living conditions of many people. The article deals with the problem areas of the intersection of 20-ya Liniya street – Sholokhov Avenue in Rostov-on-Don. Problem Statement. The purpose of this paper is to improve environmental safety at the intersection of 20-ya Liniya street – Sholokhov Avenue in Rostov-on-Don by reducing emissions from road transport through the proposed measures to reorganize traffic on this section of the road network. Theoretical Part. The article provides an assessment of environmental and road safety on the road network section before applying the proposed measures. The measures are listed and justified that would help improve the conditions for road transport at the selected intersection and reduce emissions from road transport, which would improve environmental safety. The calculation of environmental indicators was made after the proposed measures to reduce NOx emissions by cars. Conclusion. The article analyzes the environmental indicators before and after the events, and then compares them. Based on the analysis and calculations, it is determined how much the proposed measures to optimize traffic will help reduce NOx emissions by cars.


Author(s):  
Yao Liu ◽  
Jianmai Shi ◽  
Zhong Liu ◽  
Jincai Huang ◽  
Tianren Zhou

A novel high-voltage powerline inspection system is investigated, which consists of the cooperated ground vehicle and drone. The ground vehicle acts as a mobile platform that can launch and recycle the drone, while the drone can fly over the powerline for inspection within limited endurance. This inspection system enables the drone to inspect powerline networks in a very large area. Both vehicle’ route in the road network and drone’s routes along the powerline network have to be optimized for improving the inspection efficiency, which generates a new two-layer point-arc routing problem. Two constructive heuristics are designed based on “Cluster First, Rank Second” and “Rank First, Split Second”. Then local search strategies are developed to further improve the quality of the solution. To test the performance of the proposed algorithms, practical cases with different-scale are designed based on the road network and powerline network of Ji’an, China. Sensitivity analysis on the parameters related with the drone’s inspection speed and battery capacity is conducted. Computational results indicate that technical improvement on the inspection sensor is more important for the cooperated ground vehicle and drone system.


2012 ◽  
Vol 22 (6) ◽  
pp. 405-411
Author(s):  
Mohammad Reza Jelokhani-Niaraki ◽  
Ali Asghar Alesheikh ◽  
Abbas Alimohammadi ◽  
Abolghasem Sadeghi-Niaraki

In recent years, the development of the GIS-T (Geographic Information System for Transportation) applications has gained much attention, providing the transportation planners and managers with in-depth knowledge to achieve better decisions. Needless to say, developing a successful GIS for transportation applications is highly dependent on the design of a well-structured data model. Dynamic segmentation (DS) data model is a popular one being used more and more for different GIS-T analyses, serving as a data model that splits linear features into new set of segments wherever its attributes change. In most cases, the sets of segments presenting a particular attribute change frequently. Transportation managers place great importance on having regular update and revision of segmented data to ensure correct and precise decisions are made. However, updating the segmented data manually is a difficult task and a time-consuming process to do, demanding an automatic approach. To alleviate this, the present study describes a rule-based method using topological concept to simply update road segments and replace the manual tasks that users are to carry out. The proposed approach was employed and implemented on real road network data of the City of Tehran provided by the Road Maintenance and Transportation Organization (RMTO) of Iran. The practical results demonstrated that the time, cost, human-type errors, and complexity involved in update tasks are all reduced. KEYWORDS: GIS-T, dynamic segmentation, segment, automatic update, change type, rule


Author(s):  
Yi Li ◽  
Weifeng Li ◽  
Qing Yu ◽  
Han Yang

Urban traffic congestion is one of the urban diseases that needs to be solved urgently. Research has already found that a few road segments can significantly influence the overall operation of the road network. Traditional congestion mitigation strategies mainly focus on the topological structure and the transport performance of each single key road segment. However, the propagation characteristics of congestion indicate that the interaction between road segments and the correlation between travel speed and traffic volume should also be considered. The definition is proposed for “key road cluster” as a group of road segments with strong correlation and spatial compactness. A methodology is proposed to identify key road clusters in the network and understand the operating characteristics of key road clusters. Considering the correlation between travel speed and traffic volume, a unidirectional-weighted correlation network is constructed. The community detection algorithm is applied to partition road segments into key road clusters. Three indexes are used to evaluate and describe the characteristic of these road clusters, including sensitivity, importance, and IS. A case study is carried out using taxi GPS data of Shanghai, China, from May 1 to 17, 2019. A total of 44 key road clusters are identified in the road network. According to their spatial distribution patterns, these key road clusters can be classified into three types—along with network skeletons, around transportation hubs, and near bridges. The methodology unveils the mechanism of congestion formation and propagation, which can offer significant support for traffic management.


2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Tolesa Hundesa Muleta ◽  
Legesse Lemecha Obsu

In this paper, the analyses of traffic evolution on the road network of a roundabout having three entrances and three exiting legs are conducted from macroscopic point of view. The road networks of roundabouts are modeled as a merging and diverging types 1×2 and 2×1 junctions. To study traffic evolution at junction, two cases have been considered, namely, demand and supply limited cases. In each case, detailed mathematical analysis and numerical tests have been presented. The analysis in the case of demand limited showed that rarefaction wave fills the portion of the road network in time. In the contrary, in supply limited case, traffic congestion occurs at merging junctions and shock wave propagating back results in reducing the performance of a roundabout to control traffic dynamics. Also, we illustrate density and flux profiles versus space discretization at different time steps via numerical simulation with the help of Godunov scheme.


Author(s):  
Yuichiro KANEKO ◽  
Kazuhisa OGIWARA ◽  
Hisashi TAKAGI ◽  
Katsuhiro ITO ◽  
Tetsuya MATSUSHIMA

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