Author: Hyeonsup Lim
Publisher:
ISBN:
Category : Aggregation operators
Languages : en
Pages : 113
Book Description
Data aggregation, which is a process to combine information by defined groups for statistical analysis, summary, data size reduction, or other purposes, has fundamental challenges, such as loss of the original information. Improper data aggregation, such as sampling bias or incorrect calculation of average, may cause misreading of information. In first chapter, it is revealed that the harmonic mean, which is used to calculate space mean speed for fixed segment, has a sampling bias, i.e., overestimation with small samples. The several impact analyses show that the sampling bias is affected by sampling rate, time interval, segment length, and distribution type. If the data aggregation is properly used, it can help us improve analytical efficiency, encounter some of critical problems, or reveal its casualties and other relevant information. Second and third chapters utilize the aggregation of multi-source data to estimate error distributions of data sources and improve accuracy of their measurements. This is a leaping point of evaluating data sources as the proposed model does not require ground truth data. Second chapter focuses more on the methodology, i.e., a modified Approximate Bayesian Computation, incorporated to construct the error distribution with numerous simulations. In the simulated experiment, the proposed model outperformed the alternative approach, which is a conventional way of evaluating data source that is gathering error information by comparing with ground data source. Several sensitivity analyses explore that how the model performance is affected by sample size, number of data sources, and distribution types. The proposed model in chapter II is limited to one dimensional variable, and then the application is expanded to improving the position and distance measurement of connected vehicle environment. The proposed model can be used to further improve the accuracy of vehicle positioning with other existing methods, such as simultaneous localization and mapping (SLAM). The estimation process can be conducted in real-time operation, and the learning process will try to keep improving the accuracy of estimation. The results show that the proposed model noticeably improves the accuracy of position and distance measurements.
Errors and Truths from Transportation Data Aggregation
Author: Hyeonsup Lim
Publisher:
ISBN:
Category : Aggregation operators
Languages : en
Pages : 113
Book Description
Data aggregation, which is a process to combine information by defined groups for statistical analysis, summary, data size reduction, or other purposes, has fundamental challenges, such as loss of the original information. Improper data aggregation, such as sampling bias or incorrect calculation of average, may cause misreading of information. In first chapter, it is revealed that the harmonic mean, which is used to calculate space mean speed for fixed segment, has a sampling bias, i.e., overestimation with small samples. The several impact analyses show that the sampling bias is affected by sampling rate, time interval, segment length, and distribution type. If the data aggregation is properly used, it can help us improve analytical efficiency, encounter some of critical problems, or reveal its casualties and other relevant information. Second and third chapters utilize the aggregation of multi-source data to estimate error distributions of data sources and improve accuracy of their measurements. This is a leaping point of evaluating data sources as the proposed model does not require ground truth data. Second chapter focuses more on the methodology, i.e., a modified Approximate Bayesian Computation, incorporated to construct the error distribution with numerous simulations. In the simulated experiment, the proposed model outperformed the alternative approach, which is a conventional way of evaluating data source that is gathering error information by comparing with ground data source. Several sensitivity analyses explore that how the model performance is affected by sample size, number of data sources, and distribution types. The proposed model in chapter II is limited to one dimensional variable, and then the application is expanded to improving the position and distance measurement of connected vehicle environment. The proposed model can be used to further improve the accuracy of vehicle positioning with other existing methods, such as simultaneous localization and mapping (SLAM). The estimation process can be conducted in real-time operation, and the learning process will try to keep improving the accuracy of estimation. The results show that the proposed model noticeably improves the accuracy of position and distance measurements.
Publisher:
ISBN:
Category : Aggregation operators
Languages : en
Pages : 113
Book Description
Data aggregation, which is a process to combine information by defined groups for statistical analysis, summary, data size reduction, or other purposes, has fundamental challenges, such as loss of the original information. Improper data aggregation, such as sampling bias or incorrect calculation of average, may cause misreading of information. In first chapter, it is revealed that the harmonic mean, which is used to calculate space mean speed for fixed segment, has a sampling bias, i.e., overestimation with small samples. The several impact analyses show that the sampling bias is affected by sampling rate, time interval, segment length, and distribution type. If the data aggregation is properly used, it can help us improve analytical efficiency, encounter some of critical problems, or reveal its casualties and other relevant information. Second and third chapters utilize the aggregation of multi-source data to estimate error distributions of data sources and improve accuracy of their measurements. This is a leaping point of evaluating data sources as the proposed model does not require ground truth data. Second chapter focuses more on the methodology, i.e., a modified Approximate Bayesian Computation, incorporated to construct the error distribution with numerous simulations. In the simulated experiment, the proposed model outperformed the alternative approach, which is a conventional way of evaluating data source that is gathering error information by comparing with ground data source. Several sensitivity analyses explore that how the model performance is affected by sample size, number of data sources, and distribution types. The proposed model in chapter II is limited to one dimensional variable, and then the application is expanded to improving the position and distance measurement of connected vehicle environment. The proposed model can be used to further improve the accuracy of vehicle positioning with other existing methods, such as simultaneous localization and mapping (SLAM). The estimation process can be conducted in real-time operation, and the learning process will try to keep improving the accuracy of estimation. The results show that the proposed model noticeably improves the accuracy of position and distance measurements.
Estimating Aggregation Errors in Transportation Problems
Author: Nancy K. Keith
Publisher:
ISBN:
Category : Physical distribution of goods
Languages : en
Pages : 44
Book Description
Publisher:
ISBN:
Category : Physical distribution of goods
Languages : en
Pages : 44
Book Description
Consequences of Certain Data Errors in the Transportation Planning Process
Author: Ralph Wildy Zimmer
Publisher:
ISBN:
Category : Traffic surveys
Languages : en
Pages : 296
Book Description
Publisher:
ISBN:
Category : Traffic surveys
Languages : en
Pages : 296
Book Description
Analysis of Errors Due to Demand Data Aggregation in the Set Covering and Maximal Covering Location Problems
Author: John Richard Current
Publisher:
ISBN:
Category : Error analysis (Mathematics)
Languages : en
Pages : 14
Book Description
Publisher:
ISBN:
Category : Error analysis (Mathematics)
Languages : en
Pages : 14
Book Description
A Guidebook for Using American Community Survey Data for Transportation Planning
Author: National Cooperative Highway Research Program
Publisher: Transportation Research Board
ISBN: 0309099110
Category : American community survey
Languages : en
Pages : 285
Book Description
Explores incorporating the U.S. Census Bureau's American Community Survey (ACS) data into the transportation planning processes at national, state, metropolitan, and local levels. The report examines ACS data and products and demonstrates their uses within a wide range of transportation planning applications.
Publisher: Transportation Research Board
ISBN: 0309099110
Category : American community survey
Languages : en
Pages : 285
Book Description
Explores incorporating the U.S. Census Bureau's American Community Survey (ACS) data into the transportation planning processes at national, state, metropolitan, and local levels. The report examines ACS data and products and demonstrates their uses within a wide range of transportation planning applications.
International Encyclopedia of Transportation
Author:
Publisher: Elsevier
ISBN: 0081026722
Category : Law
Languages : en
Pages : 4418
Book Description
In an increasingly globalised world, despite reductions in costs and time, transportation has become even more important as a facilitator of economic and human interaction; this is reflected in technical advances in transportation systems, increasing interest in how transportation interacts with society and the need to provide novel approaches to understanding its impacts. This has become particularly acute with the impact that Covid-19 has had on transportation across the world, at local, national and international levels. Encyclopedia of Transportation, Seven Volume Set - containing almost 600 articles - brings a cross-cutting and integrated approach to all aspects of transportation from a variety of interdisciplinary fields including engineering, operations research, economics, geography and sociology in order to understand the changes taking place. Emphasising the interaction between these different aspects of research, it offers new solutions to modern-day problems related to transportation. Each of its nine sections is based around familiar themes, but brings together the views of experts from different disciplinary perspectives. Each section is edited by a subject expert who has commissioned articles from a range of authors representing different disciplines, different parts of the world and different social perspectives. The nine sections are structured around the following themes: Transport Modes; Freight Transport and Logistics; Transport Safety and Security; Transport Economics; Traffic Management; Transport Modelling and Data Management; Transport Policy and Planning; Transport Psychology; Sustainability and Health Issues in Transportation. Some articles provide a technical introduction to a topic whilst others provide a bridge between topics or a more future-oriented view of new research areas or challenges. The end result is a reference work that offers researchers and practitioners new approaches, new ways of thinking and novel solutions to problems. All-encompassing and expertly authored, this outstanding reference work will be essential reading for all students and researchers interested in transportation and its global impact in what is a very uncertain world. Provides a forward looking and integrated approach to transportation Updated with future technological impacts, such as self-driving vehicles, cyber-physical systems and big data analytics Includes comprehensive coverage Presents a worldwide approach, including sets of comparative studies and applications
Publisher: Elsevier
ISBN: 0081026722
Category : Law
Languages : en
Pages : 4418
Book Description
In an increasingly globalised world, despite reductions in costs and time, transportation has become even more important as a facilitator of economic and human interaction; this is reflected in technical advances in transportation systems, increasing interest in how transportation interacts with society and the need to provide novel approaches to understanding its impacts. This has become particularly acute with the impact that Covid-19 has had on transportation across the world, at local, national and international levels. Encyclopedia of Transportation, Seven Volume Set - containing almost 600 articles - brings a cross-cutting and integrated approach to all aspects of transportation from a variety of interdisciplinary fields including engineering, operations research, economics, geography and sociology in order to understand the changes taking place. Emphasising the interaction between these different aspects of research, it offers new solutions to modern-day problems related to transportation. Each of its nine sections is based around familiar themes, but brings together the views of experts from different disciplinary perspectives. Each section is edited by a subject expert who has commissioned articles from a range of authors representing different disciplines, different parts of the world and different social perspectives. The nine sections are structured around the following themes: Transport Modes; Freight Transport and Logistics; Transport Safety and Security; Transport Economics; Traffic Management; Transport Modelling and Data Management; Transport Policy and Planning; Transport Psychology; Sustainability and Health Issues in Transportation. Some articles provide a technical introduction to a topic whilst others provide a bridge between topics or a more future-oriented view of new research areas or challenges. The end result is a reference work that offers researchers and practitioners new approaches, new ways of thinking and novel solutions to problems. All-encompassing and expertly authored, this outstanding reference work will be essential reading for all students and researchers interested in transportation and its global impact in what is a very uncertain world. Provides a forward looking and integrated approach to transportation Updated with future technological impacts, such as self-driving vehicles, cyber-physical systems and big data analytics Includes comprehensive coverage Presents a worldwide approach, including sets of comparative studies and applications
Geographic Information Systems for Transportation
Author: Harvey J. Miller
Publisher: Oxford University Press, USA
ISBN: 9780195123944
Category : Science
Languages : en
Pages : 474
Book Description
GIS data and tools are revolutionizing transportation research and decision making, allowing transportation analysts and professionals to understand and solve complex transportation problems that were previously impossible. Here, Miller and Shaw present a comprehensive discussion of fundamental geographic science and the applications of these principles using GIS and other software tools. By providing thorough and accessible discussions of transportation analysis within a GIS environment, this volume fills a critical niche in GIS-T and GIS literature.
Publisher: Oxford University Press, USA
ISBN: 9780195123944
Category : Science
Languages : en
Pages : 474
Book Description
GIS data and tools are revolutionizing transportation research and decision making, allowing transportation analysts and professionals to understand and solve complex transportation problems that were previously impossible. Here, Miller and Shaw present a comprehensive discussion of fundamental geographic science and the applications of these principles using GIS and other software tools. By providing thorough and accessible discussions of transportation analysis within a GIS environment, this volume fills a critical niche in GIS-T and GIS literature.
Improving Transportation Information Resilience
Author: Yueyue Fan
Publisher:
ISBN:
Category :
Languages : en
Pages : 37
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 37
Book Description
Solving Transportation Problems Via Aggregation
Author: Richard Winthrop Taylor
Publisher:
ISBN:
Category : Transportation
Languages : en
Pages : 60
Book Description
This paper deals with the solution of large scale transportation problems by aggregation as a special case of constraint and variable aggregation in linear programming. Using cluster analysis, an appropriate form of aggregation will be used. If the bounds developed at this point are not tight enough, a suitable unaggregation step will be specified. Computational results are presented. (Author).
Publisher:
ISBN:
Category : Transportation
Languages : en
Pages : 60
Book Description
This paper deals with the solution of large scale transportation problems by aggregation as a special case of constraint and variable aggregation in linear programming. Using cluster analysis, an appropriate form of aggregation will be used. If the bounds developed at this point are not tight enough, a suitable unaggregation step will be specified. Computational results are presented. (Author).
Urban Transportation Abstracts
Author:
Publisher:
ISBN:
Category : Urban transportation
Languages : en
Pages : 596
Book Description
Publisher:
ISBN:
Category : Urban transportation
Languages : en
Pages : 596
Book Description