scholarly journals Detailed Streetspace Modelling for Multiple Applications: Discussions on the Proposed CityGML 3.0 Transportation Model

2020 ◽  
Vol 9 (10) ◽  
pp. 603
Author(s):  
Christof Beil ◽  
Roland Ruhdorfer ◽  
Theresa Coduro ◽  
Thomas H. Kolbe
Keyword(s):  
Urban Areas ◽  
Smart Cities ◽  
Three Dimensional ◽  
Data Availability ◽  
Minor Role ◽  
Extensive Literature ◽  
Transportation Model ◽  
Potential Applications ◽  
A Minor ◽  
City Models

In the context of smart cities and digital twins, three-dimensional semantic city models are increasingly used for the analyses of large urban areas. While the representation of buildings, terrain, and vegetation has become standard for most city models, detailed spatio-semantic representations of streetspace have played a minor role so far. This is now changing (1) because of data availability, and (2) because recent and emerging applications require having detailed data about the streetspace. The upcoming version 3.0 of the international standard CityGML provides a substantially updated data model regarding the transportation infrastructure, including the representation of the streetspace. However, there already exist a number of other standards and data formats dealing with the representation and exchange of streetspace data. Thus, based on an extensive literature review of potential applications as well as discussions and collaborations with relevant stakeholders, seven key modelling aspects of detailed streetspace models are identified. This allows a structured discussion of representational capabilities of the proposed CityGML3.0 Transportation Model with respect to these aspects and in comparison to the other standards. Subsequently, it is shown that CityGML3.0 meets most of these aspects and that streetspace models can be derived from various data sources and for different cities. Models generated compliant to the CityGML standard are immediately usable for a number of applications. This is demonstrated for some applications, such as land use management, solar potential analyses, and traffic and pedestrian simulations.

scholarly journals CITYGML AND THE STREETS OF NEW YORK - A PROPOSAL FOR DETAILED STREET SPACE MODELLING

2017 ◽  
Vol IV-4/W5 ◽  
pp. 9-16 ◽  
Author(s):  
C. Beil ◽  
T. H. Kolbe
Keyword(s):  
New York ◽  
Urban Areas ◽  
Semantic Representation ◽  
Three Dimensional ◽  
Open Data ◽  
Levels Of Detail ◽  
3D City Model ◽  
Street Space ◽  
Potential Applications ◽  
City Models

Three-dimensional semantic city models are increasingly used for the analysis of large urban areas. Until now the focus has mostly been on buildings. Nonetheless many applications could also benefit from detailed models of public street space for further analysis. However, there are only few guidelines for representing roads within city models. Therefore, related standards dealing with street modelling are examined and discussed. Nearly all street representations are based on linear abstractions. However, there are many use cases that require or would benefit from the detailed geometrical and semantic representation of street space. A variety of potential applications for detailed street space models are presented. Subsequently, based on related standards as well as on user requirements, a concept for a CityGML-compliant representation of street space in multiple levels of detail is developed. In the course of this process, the CityGML Transportation model of the currently valid OGC standard CityGML2.0 is examined to discover possibilities for further developments. Moreover, a number of improvements are presented. Finally, based on open data sources, the proposed concept is implemented within a semantic 3D city model of New York City generating a detailed 3D street space model for the entire city. As a result, 11 thematic classes, such as roadbeds, sidewalks or traffic islands are generated and enriched with a large number of thematic attributes.

scholarly journals FIRST STEPS TOWARDS AN INTEGRATED CITYGML-BASED 3D MODEL OF VIENNA

2016 ◽  
Vol III-4 ◽  
pp. 139-146 ◽  
Author(s):  
G. Agugiaro
Keyword(s):  
Energy Use ◽  
Smart Cities ◽  
Three Dimensional ◽  
3D City Model ◽  
First Results ◽  
Sustainable Energy Systems ◽  
City Model ◽  
Set Up ◽  
The City ◽  
City Models

This paper presents and discusses the results regarding the initial steps (selection, analysis, preparation and eventual integration of a number of datasets) for the creation of an integrated, semantic, three-dimensional, and CityGML-based virtual model of the city of Vienna. CityGML is an international standard conceived specifically as information and data model for semantic city models at urban and territorial scale. It is being adopted by more and more cities all over the world. <br><br> The work described in this paper is embedded within the European Marie-Curie ITN project “Ci-nergy, Smart cities with sustainable energy systems”, which aims, among the rest, at developing urban decision making and operational optimisation software tools to minimise non-renewable energy use in cities. Given the scope and scale of the project, it is therefore vital to set up a common, unique and spatio-semantically coherent urban model to be used as information hub for all applications being developed. This paper reports about the experiences done so far, it describes the test area and the available data sources, it shows and exemplifies the data integration issues, the strategies developed to solve them in order to obtain the integrated 3D city model. The first results as well as some comments about their quality and limitations are presented, together with the discussion regarding the next steps and some planned improvements.

scholarly journals City Maker: Reconstruction of Cities from OpenStreetMap Data for Environmental Visualization and Simulations

2019 ◽  
Vol 8 (7) ◽  
pp. 298 ◽  
Author(s):  
I. Alihan Hadimlioglu ◽  
Scott A. King
Keyword(s):  
Emergency Management ◽  
Urban Areas ◽  
Smart Cities ◽  
Data Availability ◽  
Data Formats ◽  
3D Processing ◽  
Environmental Simulations ◽  
Simulation Parameters ◽  
The City ◽  
Different Sources

Recent innovations in 3D processing and availability of geospatial data have contributed largely to more comprehensive solutions to data visualization. As various data formats are utilized to describe the data, a combination of layers from different sources allow us to represent 3D urban areas, contributing to ideas of emergency management and smart cities. This work focuses on 3D urban environment reconstruction using crowdsourced OpenStreetMap data. Once the data are extracted, the visualization pipeline draws features using coloring for added context. Moreover, by structuring the layers and entities through the addition of simulation parameters, the generated environment is made simulation ready for further use. Results show that urban areas can be properly visualized in 3D using OpenStreetMap data given data availability. The simulation-ready environment was tested using hypothetical flooding scenarios, which demonstrated that the added parameters can be utilized in environmental simulations. Furthermore, an efficient restructuring of data was implemented for viewing the city information once the data are parsed.

Combining dynamic city sensors to build a three-dimensional thermal environment cloud information system for smart cities

Impact ◽  
2020 ◽  
Vol 2020 (6) ◽  
pp. 26-28
Author(s):  
Kochiu Wu
Keyword(s):  
Information System ◽  
Urban Areas ◽  
Chinese Culture ◽  
Energy Savings ◽  
Thermal Environment ◽  
Smart Cities ◽  
Three Dimensional ◽  
Policy Makers ◽  
University Of Technology ◽  
New Information

Professors Ko-Chiu Wu, Chih-Hong Huang and Hsiao-Tung Chang from the National Taipei University of Technology and Chinese Culture University are combining dynamic city sensors to build a 3D thermal environment cloud information system for smart cities. They seek to uncover new information about urban heat island (UHI) by describing the dynamic phenomena underway. The ultimate aim of this study is to survey the thermal environment data in the horizontal and vertical interspace of urban areas. The data and insight the team gathers will be extremely useful to policy makers and city planners, as well as designing urban spaces with the comfort of citizens in mind, it is hoped they will be able to mitigate the effects of UHI and even make energy savings using the 3D maps.

scholarly journals Flow Topology of Three-Dimensional Spherical Flame in Shock Accelerated Flows

2016 ◽  
Vol 2016 ◽  
pp. 1-12
Author(s):  
Yuejin Zhu ◽  
Lei Yu ◽  
Gang Dong ◽  
Jianfeng Pan ◽  
Zhenhua Pan
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Joint Probability ◽  
Reflected Shock Wave ◽  
Minor Role ◽  
Flow Topology ◽  
Reflected Shock ◽  
Compression And Expansion ◽  
Scale Turbulence ◽  
A Minor

The flow topologies of compressible large-scale distorted flames are studied by means of the analysis of the invariants of the velocity gradient tensor (VGT). The results indicate that compressibility plays a minor role in the distorted flame zone. And the joint probability density function (p.d.f.) of the Q-R diagram appears as a teardrop shape, which is a universal feature of turbulence. Therefore, the distorted flame exhibits the characteristic of large-scale turbulence combustion, especially behind the reflected shock wave, while the p.d.f. of the QS⁎-QW diagram implies that the dissipation is enhanced in the compression and expansion regions, where it is higher than that when P=0. Furthermore, we identify that the flame evolution is dominated by rotation by means of a quantitative statistical study, and the SFS topology is the predominant flow pattern. Not surprisingly, negative dilatation could suppress the unstable topologies, whereas positive dilatation could suppress the stable topologies.

scholarly journals COVID, CITIES and CLIMATE: Historical Precedents and Potential Transitions for the New Economy

Urban Science ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 32 ◽  
Author(s):  
Peter Newman AO
Keyword(s):  
Global Economy ◽  
New Technologies ◽  
Smart Cities ◽  
New Economy ◽  
Minor Role ◽  
Cultural Changes ◽  
Strong Base ◽  
Regenerative Development ◽  
A Minor ◽  
Economic Transitions

The 2020 collapse of the global economy due to the Covid-19 pandemic has enabled us to think about long term trends and what the future could hold for our cities and regions, especially due to the climate agenda. The paper sets out the historical precedents for economic transitions after collapses that unleash new technologically based innovation waves. These are shown to be associated with different energy and infrastructure priorities and their transport and resulting urban forms. The new technologies in the past were emerging but mainstreamed as the new economy was built on new investments. The paper suggests that the new economy, for the next 30 years, is likely to be driven by the Paris Agreement and Sustainable Development Goals (SDGs) agendas (summarised as zero carbon–zero poverty) and will have a strong base in a cluster of innovative technologies: renewable energy, electromobility, smart cities, hydrogen-based industry, circular economy technologies, and biophilic urbanism. The first three are well underway, and the other three will need interventions if not cultural changes and may miss being mainstreamed in this recovery but could still play a minor role in the new economy. The resulting urban transformations are likely to build on Covid-19 through “global localism” and could lead to five new features: (1) relocalised centres with distributed infrastructure, (2) tailored innovations in each urban fabric, (3) less car dependence, (4) symbiotic partnerships for funding, and (5) rewritten manuals for urban professionals. This period needs human creativity to play a role in revitalising the human dimension of cities. The next wave following this may be more about regenerative development.

scholarly journals Exploring the role of City Networks in supporting urban resilience to COVID-19 in conflict-affected settings

Open Health ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 1-20
Author(s):  
Kristen Meagher ◽  
Nassim El Achi ◽  
Gemma Bowsher ◽  
Abdulkarim Ekzayez ◽  
Preeti Patel
Keyword(s):  
Thematic Analysis ◽  
Urban Areas ◽  
Minor Role ◽  
Urban Resilience ◽  
Global Challenges ◽  
Conflict Settings ◽  
A Minor ◽  
National Governments ◽  
Global Population

Abstract Background: It is estimated that by 2050, almost 70 percent of the global population will be residing in urban areas. In recent years, cities have become central in tackling key urban challenges and have demonstrated greater flexibility in policymaking and innovation than national governments. Cities are currently more inclined to learn from each other via networks, partnerships, and pairings to develop solutions to many global challenges including pandemics such as COVID-19. Aim: To explore the role cities and city networks present in supporting urban resilience to pandemics focusing on conflict-affected settings. Methods: A desk-based literature review of academic and grey sources was conducted followed by thematic analysis. Results: Although most COVID-19 response plans have been developed and implemented by governments, the pandemic has revealed the significant potential for city networks in providing platforms for knowledge sharing and coordination of mitigation plans to address pandemic-specific interventions. We found that in conflict settings, city networks continue to play only a minor role, if any, compared to humanitarian and informal actors. Conclusion: City networks have the potential to contribute to strengthening global collaborative approaches to pandemic responses, but this has not been given sufficient investment and even less so in conflict-affected settings. It is essential for these networks to be integrated within a wider multidisciplinary and multisectoral platform that includes academics, humanitarian and informal actors.

Investigation of Through-Flow Hypothesis in a Turbine Cascade Using a 3D Navier-Stokes Computation

1993 ◽  
Author(s):  
G. Perrin ◽  
F. Leboeuf
Keyword(s):  
Kinetic Energy ◽  
Three Dimensional ◽  
Radial Pressure ◽  
Momentum Balance ◽  
Navier Stokes ◽  
Minor Role ◽  
Passage Vortex ◽  
Spatial Fluctuations ◽  
Flow Variables ◽  
A Minor

The results of a computation, performed with a three-dimensional Navier-Stokes computation at ONERA, have been averaged in the blade-to-blade direction; the spatial fluctuations around the averaged flow variables have also been determined. It has then been possible to estimate all terms in the average components of the momentum equations. The comparison of the two-dimensional balances of these three equations shows that the shear stress play a minor role in the momentum balance, except on the dissipation of the passage vortex kinetic energy downstream of the blade trailing edges. The kinetic energy of the spanwise component of the velocity spatial fluctuations has a very strong influence on the radial pressure gradient; it introduces a convection effect. This is a key effect for all these balances.

Primary and secondary instabilities in the wake of a cylinder with free ends

1997 ◽  
Vol 332 ◽  
pp. 295-339 ◽  
Author(s):  
Christophe Dauchy ◽  
Jan Dušek ◽  
Philippe Fraunié
Keyword(s):  
Aspect Ratio ◽  
Limit Cycle ◽  
Three Dimensional ◽  
Secondary Instability ◽  
Instability Threshold ◽  
Three Dimensions ◽  
Finite Cylinder ◽  
Minor Role ◽  
A Minor ◽  
Primary Instability

The wake of a finite cylinder with free ends and an aspect ratio of 21.4 is simulated in three-dimensions and analysed theoretically. Close to the primary-instability threshold, the flow is shown to settle on a limit cycle with a uniform frequency throughout the flow-field. About 20% above the primary-instability threshold, a secondary instability sets in and the limit cycle becomes unstable. The new attractor of the flow can be identified as a limit T2-torus characterized by two incommensurate frequencies. One of them is shown to evolve continuously from the primary-instability frequency, the other one, about 17 times smaller near the secondary-instability threshold, generates a slow modulation of the oscillations in the wake. The limit cycle and the limit torus are described in terms of their Fourier expansion and the spatial distribution of the most relevant Fourier components is investigated. The theoretical analysis and numerical results given shed some light on the mechanisms underlying a number of known but not satisfactorily explained three-dimensional effects in wakes of finite cylinders such as the ambiguity in the dominant Strouhal frequency, the existence of zones with different frequencies spanwise in the wake, the discreteness of coexisting frequencies observed in the wake as well as the spatial uniformity of the beating period. They moreover explain the Reynolds number variation of these effects and identify the recirculation around the cylinder ends as basically responsible for the onset of the secondary instability. The results are compared to the case of a cylinder with aspect ratio of 10.7 to determine the basic trends in aspect ratio dependence. It is shown that qualitatively the same behaviour is obtained, but that the secondary-instability threshold is shifted significantly upward to about twice the primary-instability threshold. Simulations of the wake of a finite NACA wing with incidence show that the form of the cross-section plays a minor role.

Investigation of Throughflow Hypothesis in a Turbine Cascade Using a Three-Dimensional Navier–Stokes Computation

1995 ◽  
Vol 117 (1) ◽  
pp. 126-132
Author(s):  
G. Perrin ◽  
F. Leboeuf
Keyword(s):  
Kinetic Energy ◽  
Three Dimensional ◽  
Radial Pressure ◽  
Momentum Balance ◽  
Navier Stokes ◽  
Minor Role ◽  
Passage Vortex ◽  
Spatial Fluctuations ◽  
Flow Variables ◽  
A Minor

The results of a computation, performed with a three-dimensional Navier–Stokes computation at ONERA, have been averaged in the blade-to-blade direction; the spatial fluctuations around the averaged flow variables have also been determined. It has then been possible to estimate all terms in the average components of the momentum equations. The comparison of the two-dimensional balances of these three equations shows that the shear stress plays a minor role in the momentum balance, except on the dissipation of the passage vortex kinetic energy downstream of the blade trailing edges. The kinetic energy of the spanwise component of the velocity spatial fluctuations has a very strong influence on the radial pressure gradient; it introduces a convection effect. This is a key effect for all these balances.

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