scholarly journals An Efficient Method of Sharing Mass Spatio-Temporal Trajectory Data Based on Cloudera Impala for Traffic Distribution Mapping in an Urban City

Sensors ◽  
2016 ◽  
Vol 16 (11) ◽  
pp. 1813 ◽  
Author(s):  
Lianjie Zhou ◽  
Nengcheng Chen ◽  
Sai Yuan ◽  
Zeqiang Chen
Keyword(s):  
Efficient Method ◽  
Trajectory Data ◽  
Traffic Distribution ◽  
Urban City ◽  
Distribution Mapping ◽  
Spatio Temporal ◽  
Temporal Trajectory

Online Approach for Spatio-Temporal Trajectory Data Reduction for Portable Devices

2013 ◽  
Vol 28 (4) ◽  
pp. 597-604 ◽  
Author(s):  
Heemin Park ◽  
Young-Jun Lee ◽  
Jinseok Chae ◽  
Wonik Choi
Keyword(s):  
Data Reduction ◽  
Portable Devices ◽  
Trajectory Data ◽  
Spatio Temporal ◽  
Temporal Trajectory

scholarly journals Safe contact tracing for COVID-19: A method without privacy breach using functional encryption techniques based-on spatio-temporal trajectory data

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0242758
Author(s):  
Wooil Kim ◽  
Hyubjin Lee ◽  
Yon Dohn Chung
Keyword(s):  
Early Detection ◽  
South Korea ◽  
Contact Tracing ◽  
Functional Encryption ◽  
Trajectory Data ◽  
The Public ◽  
Privacy Breach ◽  
Spatio Temporal ◽  
Temporal Trajectory ◽  
Tracing Method

The COVID-19 pandemic has spread all over the globe. In the absence of a vaccine, a small number of countries have managed to control the diffusion of viruses by early detection and early quarantine. South Korea, one of the countries which have kept the epidemics well-controlled, has opened the infected patients’ trajectory to the public. Such a reaction has been regarded as an effective method, however, serious privacy breach cases have been issued in South Korea. Furthermore, some suspected contacts have refused to take infection tests because they are afraid of being exposed. To solve this problem, we propose a privacy-preserving contact tracing method based on spatio-temporal trajectory which can be practically used in many quarantine systems. In addition, we develop a system to visualize the contact tracing workflow.

scholarly journals A Hybrid Method to Incrementally Extract Road Networks Using Spatio-Temporal Trajectory Data

2020 ◽  
Vol 9 (4) ◽  
pp. 186
Author(s):  
Yunfei Zhang ◽  
Zexu Zhang ◽  
Jincai Huang ◽  
Tingting She ◽  
Min Deng ◽  
...  
Keyword(s):  
Hybrid Method ◽  
Human Life ◽  
Rapid Development ◽  
Road Networks ◽  
Urban Traffic ◽  
Force Model ◽  
Trajectory Data ◽  
Incremental Change ◽  
Spatio Temporal ◽  
Temporal Trajectory

With the rapid development of urban traffic, accurate and up-to-date road maps are in crucial demand for daily human life and urban traffic control. Recently, with the emergence of crowdsourced mapping, a surge in academic attention has been paid to generating road networks from spatio-temporal trajectory data. However, most existing methods do not explore changing road patterns contained in multi-temporal trajectory data and it is still difficult to satisfy the precision and efficiency demands of road information extraction. Hence, in this paper, we propose a hybrid method to incrementally extract urban road networks from spatio-temporal trajectory data. First, raw trajectory data were partitioned into K time slices and were used to initialize K-temporal road networks by a mathematical morphology method. Then, the K-temporal road networks were adjusted according to a gravitation force model so as to amend their geometric inconsistencies. Finally, road networks were geometrically delineated using the k-segment fitting algorithm, and the associated road attributes (e.g., road width and driving rule) were inferred. Several case studies were examined to demonstrate that our method can effectively improve the efficiency and precision of road extraction and can make a significant attempt to mine the incremental change patterns in road networks from spatio-temporal trajectory data to help with road map renewal.

scholarly journals Safe contact tracing for COVID-19: A method without privacy breach using functional encryption techniques based-on spatio-temporal trajectory data

2020 ◽  
Author(s):  
Wooil Kim ◽  
Hyubjin Lee ◽  
Yon Dohn Chung
Keyword(s):  
Early Detection ◽  
South Korea ◽  
Contact Tracing ◽  
Functional Encryption ◽  
Trajectory Data ◽  
The Public ◽  
Privacy Breach ◽  
Spatio Temporal ◽  
Temporal Trajectory ◽  
Tracing Method

The COVID-19 pandemic has spread all over the globe. In the absence of a vaccine, a small number of countries have managed to control the diffusion of viruses by early detection and early quarantine. South Korea, one of the countries which have kept the epidemics well-controlled, has opened the infected patients' trajectory to the public. Such a reaction has been regarded as an effective method, however, serious privacy breach cases have been issued in South Korea. Furthermore, some suspected contacts have refused to take infection tests because they are afraid of being exposed. To solve this problem, we propose a privacy-preserving contact tracing method based on spatio-temporal trajectory which can be practically used in many quarantine systems. In addition, we develop a system to visualize the contact tracing workflow.

scholarly journals A novel social distancing analysis in urban public space: A new online spatio-temporal trajectory approach

2021 ◽  
Vol 68 ◽  
pp. 102765
Author(s):  
Jie Su ◽  
Xiaohai He ◽  
Linbo Qing ◽  
Tong Niu ◽  
Yongqiang Cheng ◽  
...  
Keyword(s):  
Public Space ◽  
Urban Public Space ◽  
Social Distancing ◽  
Trajectory Approach ◽  
Spatio Temporal ◽  
Temporal Trajectory

scholarly journals Measuring Accessibility Based on Improved Impedance and Attractive Functions Using Taxi Trajectory Data

2020 ◽  
Vol 13 (1) ◽  
pp. 112
Author(s):  
Helai Huang ◽  
Jialing Wu ◽  
Fang Liu ◽  
Yiwei Wang
Keyword(s):  
Waiting Time ◽  
Urban Areas ◽  
Transportation Systems ◽  
Trajectory Data ◽  
Peak Period ◽  
Important Indicator ◽  
Destination Attractiveness ◽  
Urban Accessibility ◽  
Spatio Temporal ◽  
Taxi Trajectory

Accessibility has attracted wide interest from urban planners and transportation engineers. It is an important indicator to support the development of sustainable policies for transportation systems in major events, such as the COVID-19 pandemic. Taxis are a vital travel mode in urban areas that provide door-to-door services for individuals to perform urban activities. This study, with taxi trajectory data, proposes an improved method to evaluate dynamic accessibility depending on traditional location-based measures. A new impedance function is introduced by taking characteristics of the taxi system into account, such as passenger waiting time and the taxi fare rule. An improved attraction function is formulated by considering dynamic availability intensity. Besides, we generate five accessibility scenarios containing different indicators to compare the variation of accessibility. A case study is conducted with the data from Shenzhen, China. The results show that the proposed method found reduced urban accessibility, but with a higher value in southern center areas during the evening peak period due to short passenger waiting time and high destination attractiveness. Each spatio-temporal indicator has an influence on the variation in accessibility.

scholarly journals Extracting Stops from Spatio-Temporal Trajectories within Dynamic Contextual Features

2021 ◽  
Vol 13 (2) ◽  
pp. 690
Author(s):  
Tao Wu ◽  
Huiqing Shen ◽  
Jianxin Qin ◽  
Longgang Xiang
Keyword(s):  
Moving Objects ◽  
Major Effect ◽  
Location Based Services ◽  
Trajectory Data ◽  
The Road ◽  
Contextual Features ◽  
Novel Approach ◽  
Gps Trajectories ◽  
Time Distance ◽  
Spatio Temporal

Identifying stops from GPS trajectories is one of the main concerns in the study of moving objects and has a major effect on a wide variety of location-based services and applications. Although the spatial and non-spatial characteristics of trajectories have been widely investigated for the identification of stops, few studies have concentrated on the impacts of the contextual features, which are also connected to the road network and nearby Points of Interest (POIs). In order to obtain more precise stop information from moving objects, this paper proposes and implements a novel approach that represents a spatio-temproal dynamics relationship between stopping behaviors and geospatial elements to detect stops. The relationship between the candidate stops based on the standard time–distance threshold approach and the surrounding environmental elements are integrated in a complex way (the mobility context cube) to extract stop features and precisely derive stops using the classifier classification. The methodology presented is designed to reduce the error rate of detection of stops in the work of trajectory data mining. It turns out that 26 features can contribute to recognizing stop behaviors from trajectory data. Additionally, experiments on a real-world trajectory dataset further demonstrate the effectiveness of the proposed approach in improving the accuracy of identifying stops from trajectories.

Forest path condition monitoring based on crowd-based trajectory data analysis

2020 ◽  
pp. 1-18
Author(s):  
Francisco Arcas-Tunez ◽  
Fernando Terroso-Saenz
Keyword(s):  
Information Acquisition ◽  
Road Network ◽  
Road Networks ◽  
Trajectory Data ◽  
Country Road ◽  
Wide Range ◽  
Sport Activities ◽  
Path Condition ◽  
Spatio Temporal ◽  
The City

The development of Road Information Acquisition Systems (RIASs) based on the Mobile Crowdsensing (MCS) paradigm has been widely studied for the last years. In that sense, most of the existing MCS-based RIASs focus on urban road networks and assume a car-based scenario. However, there exist a scarcity of approaches that pay attention to rural and country road networks. In that sense, forest paths are used for a wide range of recreational and sport activities by many different people and they can be also affected by different problems or obstacles blocking them. As a result, this work introduces SAMARITAN, a framework for rural-road network monitoring based on MCS. SAMARITAN analyzes the spatio-temporal trajectories from cyclists extracted from the fitness application Strava so as to uncover potential obstacles in a target road network. The framework has been evaluated in a real-world network of forest paths in the city of Cieza (Spain) showing quite promising results.

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