scholarly journals Multiplex networks in metropolitan areas: generic features and local effects

2015 ◽  
Vol 12 (111) ◽  
pp. 20150651 ◽  
Author(s):  
Emanuele Strano ◽  
Saray Shai ◽  
Simon Dobson ◽  
Marc Barthelemy
Keyword(s):  
New York ◽  
Metropolitan Areas ◽  
Transportation Systems ◽  
Urban Systems ◽  
Street Network ◽  
Multilayer Network ◽  
Large Cities ◽  
Planning Decisions ◽  
Negative Side Effects ◽  
The Impact

Most large cities are spanned by more than one transportation system. These different modes of transport have usually been studied separately: it is however important to understand the impact on urban systems of coupling different modes and we report in this paper an empirical analysis of the coupling between the street network and the subway for the two large metropolitan areas of London and New York. We observe a similar behaviour for network quantities related to quickest paths suggesting the existence of generic mechanisms operating beyond the local peculiarities of the specific cities studied. An analysis of the betweenness centrality distribution shows that the introduction of underground networks operate as a decentralizing force creating congestion in places located at the end of underground lines. Also, we find that increasing the speed of subways is not always beneficial and may lead to unwanted uneven spatial distributions of accessibility. In fact, for London—but not for New York—there is an optimal subway speed in terms of global congestion. These results show that it is crucial to consider the full, multimodal, multilayer network aspects of transportation systems in order to understand the behaviour of cities and to avoid possible negative side-effects of urban planning decisions.

scholarly journals Unraveling the hidden organisation of urban systems and their mobility flows

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Riccardo Gallotti ◽  
Giulia Bertagnolli ◽  
Manlio De Domenico
Keyword(s):  
Metropolitan Areas ◽  
Small World ◽  
Urban Systems ◽  
Small World Networks ◽  
Street Network ◽  
Data Set ◽  
Large Cities ◽  
Functional Organisation ◽  
Dynamical Features ◽  
Quantitative Indicators

AbstractIncreasing evidence suggests that cities are complex systems, with structural and dynamical features responsible for a broad spectrum of emerging phenomena. Here we use a unique data set of human flows and couple it with information on the underlying street network to study, simultaneously, the structural and functional organisation of 10 world megacities. We quantify the efficiency of flow exchange between areas of a city in terms of integration and segregation using well defined measures. Results reveal unexpected complex patterns that shed new light on urban organisation. Large cities tend to be more segregated and less integrated, while their overall topological organisation resembles that of small world networks. At the same time, the heterogeneity of flows distribution might act as a catalyst for further integrating a city. Our analysis unravels how human behaviour influences, and is influenced by, the urban environment, suggesting quantitative indicators to control integration and segregation of human flows that can be used, among others, for restriction policies to adopt during emergencies and, as an interesting byproduct, allows us to characterise functional (dis)similarities of different metropolitan areas, countries, and cultures.

scholarly journals Lost in transportation: Information measures and cognitive limits in multilayer navigation

2016 ◽  
Vol 2 (2) ◽  
pp. e1500445 ◽  
Author(s):  
Riccardo Gallotti ◽  
Mason A. Porter ◽  
Marc Barthelemy
Keyword(s):  
New York ◽  
Transportation Networks ◽  
Transportation Systems ◽  
Traditional View ◽  
Multimodal Transportation ◽  
Large Cities ◽  
Amount Of Information ◽  
Information Measures ◽  
Transportation Modes ◽  
Metropolitan Networks

Cities and their transportation systems become increasingly complex and multimodal as they grow, and it is natural to wonder whether it is possible to quantitatively characterize our difficulty navigating in them and whether such navigation exceeds our cognitive limits. A transition between different search strategies for navigating in metropolitan maps has been observed for large, complex metropolitan networks. This evidence suggests the existence of a limit associated with cognitive overload and caused by a large amount of information that needs to be processed. In this light, we analyzed the world’s 15 largest metropolitan networks and estimated the information limit for determining a trip in a transportation system to be on the order of 8 bits. Similar to the “Dunbar number,” which represents a limit to the size of an individual’s friendship circle, our cognitive limit suggests that maps should not consist of more than 250 connection points to be easily readable. We also show that including connections with other transportation modes dramatically increases the information needed to navigate in multilayer transportation networks. In large cities such as New York, Paris, and Tokyo, more than 80% of the trips are above the 8-bit limit. Multimodal transportation systems in large cities have thus already exceeded human cognitive limits and, consequently, the traditional view of navigation in cities has to be revised substantially.

scholarly journals Modeling of Electrified Transportation Systems Featuring Multiple Vehicles and Complex Power Supply Layout

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8196
Author(s):  
Aleksander Jakubowski ◽  
Leszek Jarzebowicz ◽  
Mikołaj Bartłomiejczyk ◽  
Jacek Skibicki ◽  
Slawomir Judek ◽  
...  
Keyword(s):  
Power Supply ◽  
Power Transmission ◽  
Computation Time ◽  
Transportation Systems ◽  
Urban Systems ◽  
Modeling Methodology ◽  
Novel Approach ◽  
Multiple Vehicles ◽  
Traction Power Supply ◽  
The Impact

The paper proposes a novel approach to modeling electrified transportation systems. The proposed solution reflects the mechanical dynamics of vehicles as well as the distribution and losses of electric supply. Moreover, energy conversion losses between the mechanical and electrical subsystems and their bilateral influences are included. Such a complete model makes it possible to replicate, e.g., the impact of voltage drops on vehicle acceleration or the necessity of partial disposal of regenerative braking energy due to temporary lack of power transmission capability. The modeling methodology uses a flexible twin data-bus structure, which poses no limitation on the number of vehicles and enables modeling complex traction power supply structures. The proposed solution is suitable for various electrified transportation systems including suburban and urban systems. The modeling methodology is applicable i.a. to Matlab/Simulink, which makes it broadly available and customizable, and provides short computation time. The applicability and accuracy of the method were verified by comparing simulation and measurement results on an exemplary trolleybus system operating in Pilsen, Czech Republic. Simulation of daily operation of an area including four supply sections and maximal simultaneous number of nine vehicles showed a good conformance with the measured data, with the difference in the total consumed energy not exceeding 5%.

scholarly journals Sensitivity of street network capacity under the rain impact: case study of Belgrade

Transport ◽  
2017 ◽  
Vol 33 (2) ◽  
pp. 470-477 ◽  
Author(s):  
Ivan Ivanović ◽  
Jadranka Jović
Keyword(s):  
Urban Transportation ◽  
Weather Conditions ◽  
Network Capacity ◽  
Research Area ◽  
Transportation System ◽  
Transportation Systems ◽  
Street Network ◽  
Adverse Weather ◽  
Demand Sensitivity ◽  
The Impact

It is generally know that adverse weather conditions cause changes in urban transportation system. Research of weather impact on the urban transportation system was additionally intensified by actualisation of climate changes problem. In urban area, precipitation may reduce the efficiency of transportation systems, since it often results in larger travel times and higher congestion levels in street networks. Therefore, it is important to examine the impact of precipitation on the urban street capacity. In accordance with climate characteristics of research area, the focus of this paper was on the rain impact. Impact of rain was analysed only in the context of transport supply, and not of transport demand. Sensitivity of the street network capacity was chosen to represent transportation system supply. It was analysed through the changes in saturation flow rate under the rain. Results of the research have shown significant sensitivity of street network capacity on the rain impact. Moreover, the rain impact was quantified by the capacity sensitivity coefficients, which were implemented in procedure of capacity calculation.

INNOVATIVE ARCHITECTURAL IDEAS OF THE FUTURE DWELLINGS

2020 ◽  
Vol 2 (2) ◽  
pp. 67-75
Author(s):  
Dzhyhil Yu. ◽  
Keyword(s):  
Personal Responsibility ◽  
Traffic Noise ◽  
Modern World ◽  
Future Research ◽  
Housing Design ◽  
Residential Architecture ◽  
Planning Decisions ◽  
National University ◽  
Methodological Principles ◽  
The Impact

Residential architecture has one of the most conservative styles based on its specifics. However, today this type of architecture seeks to actively respond to changes in the modern world. These changes are caused by multiple factors, among them are: technological and information progress; lack of resources and environmental pollution; military conflicts and population migration etc. The purpose of this article is to summarize the experience of the Department of Architectural Environment of Lviv Polytechnic National University over housing issues and outline the methodological principles of innovation in designing both individual houses and the architectural environment of residential formations. While writing this article, we analyzed the 15-year experience of Architectural Environment's Department diploma projects. The unique feature of these projects is the priority on the design of the environment. The evolution of diploma project topics is revealed on multiple distinctive examples such as the reconstruction of old buildings in Lviv and the construction of prefabricated homes and container-type housing. Futuristic settlements are represented in projects such as “The Ocean Settlements” and “Prykarpatsk - the City of Future”. Research projects were developed to study current trends in housing design and the impact of innovative technologies on planning decisions. These projects discoursed the protection of housing from traffic noise and issues related to environmental preservation. Innovative architectural ideas of future housing, developed by students in these projects, are based on a combination of aesthetic, technical, and social components of architecture. The conclusion indicates that when educating future architects, it is important to teach them the basics of the craft, as well as the ability to defend their innovative ideas. The emphasis is placed on the importance of educating the architect's personal responsibility for their own design solutions. It is stated that professional motivation and the ability to constantly renew previously acquired knowledge and skills will be among the main tasks in training future architects.

The Impact of High-Speed Rail on the Spatial Structure of Chinese Urban Agglomerations

2020 ◽  
Vol 46 (3) ◽  
pp. 379-397
Author(s):  
Chunyang Wang
Keyword(s):  
High Speed ◽  
River Delta ◽  
City Size ◽  
High Speed Rail ◽  
Local Conditions ◽  
Urban Agglomerations ◽  
Large Cities ◽  
Spatial Systems ◽  
Economic Concentration ◽  
The Impact

This paper measures the spatial evolution of urban agglomerations to understand be er the impact of high-speed rail (HSR) construction, based on panel data from fi ve major urban agglomerations in China for the period 2004–2015. It is found that there are signi ficant regional diff erences of HSR impacts. The construction of HSR has promoted population and economic diff usion in two advanced urban agglomerations, namely the Yang e River Delta and Pearl River Delta, while promoting population and economic concentration in two relatively less advanced urban agglomerations, e.g. the middle reaches of the Yang e River and Chengdu–Chongqing. In terms of city size, HSR promotes the economic proliferation of large cities and the economic concentration of small and medium-sized cities along its routes. HSR networking has provided a new impetus for restructuring urban spatial systems. Every region should optimize the industrial division with strategic functions of urban agglomeration according to local conditions and accelerate the construction of inter-city intra-regional transport network to maximize the eff ects of high-speed rail across a large regional territory.

Roundtable Discussion of the Impact of the 4th World Symposium on Pulmonary Hypertension

2009 ◽  
Vol 8 (2) ◽  
pp. 89-94
Author(s):  
Robyn J. Barst ◽  
Marc Humbert ◽  
Ivan M. Robbins ◽  
Lewis J. Rubin ◽  
Robyn J. Park
Keyword(s):  
New York ◽  
Pulmonary Hypertension ◽  
Vascular Diseases ◽  
Assistant Professor ◽  
Associate Professor ◽  
Future Research ◽  
Columbia University ◽  
School Of Medicine ◽  
Maryland School ◽  
The Impact

A discussion among attendees of the 4th World Symposium on Pulmonary Hypertension took place to share “an insider's look” into the current and future research and treatment implications in pulmonary hypertension. Myung H. Park, MD, guest editor of this issue of Advances in Pulmonary Hypertension, Assistant Professor of Medicine and Director, Pulmonary Vascular Diseases Program, Division of Cardiology, University of Maryland School of Medicine, Baltimore, moderated the discussion. Participants included Robyn Barst, MD, Professor Emerita, Columbia University, New York; Marc Humbert, MD, PhD, Universite Paris-Sud, French Referal Center for Pulmonary Hypertension, Hopital Antoine-Beclere, Assistance Publique Hopitaux de Paris, Clamart, France; Ivan Robbins, MD, Associate Professor of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee; and Lewis J. Rubin, MD, Clinical Professor, Department of Medicine, University of California, San Diego.

COVID-19: Time-Dependent Effective Reproduction Number and Sub-notification Effect Estimation Modeling (Preprint)

2020 ◽  
Author(s):  
Eduardo Atem De Carvalho ◽  
Rogerio Atem De Carvalho
Keyword(s):  
New York ◽  
Reproduction Number ◽  
Moving Average ◽  
Real Data ◽  
Time Dependent ◽  
Initial Value ◽  
Health Authorities ◽  
Reproduction Numbers ◽  
Effect Estimation ◽  
The Impact

BACKGROUND Since the beginning of the COVID-19 pandemic, researchers and health authorities have sought to identify the different parameters that govern their infection and death cycles, in order to be able to make better decisions. In particular, a series of reproduction number estimation models have been presented, with different practical results. OBJECTIVE This article aims to present an effective and efficient model for estimating the Reproduction Number and to discuss the impacts of sub-notification on these calculations. METHODS The concept of Moving Average Method with Initial value (MAMI) is used, as well as a model for Rt, the Reproduction Number, is derived from experimental data. The models are applied to real data and their performance is presented. RESULTS Analyses on Rt and sub-notification effects for Germany, Italy, Sweden, United Kingdom, South Korea, and the State of New York are presented to show the performance of the methods here introduced. CONCLUSIONS We show that, with relatively simple mathematical tools, it is possible to obtain reliable values for time-dependent, incubation period-independent Reproduction Numbers (Rt). We also demonstrate that the impact of sub-notification is relatively low, after the initial phase of the epidemic cycle has passed.

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