302,096 research outputs found
Combining System Dynamics and Performance Management to Support Sustainable Urban Transportation Planning
In a global context characterized by a growing and rapid urbanization, achieving a good performance in the urban transportation domain is closely linked to the pursuit of sustainability, seen as the ability to satisfy social needs â i.e. improving quality of life â without compromising the ability of the future generation to satisfy theirs. Addressing sustainability assumes to deal with certain social characteristics â namely pluralism, institutional fragmentation and uncertainty â that makes the challenge complex. In order to deal with this complexity, literature embarked the road of developing detailed models to support planning activities and decision-making processes. However, a number of limits raised with reference to the usefulness of these models to planning processes. This paper suggests an innovative planning approach tailored to complex urban transportation systems. This approach is based on the Performance Management theory and the System Dynamics modelling
The Use of Historical Data in Rule-Based Modelling for Scenarios to Improve Resilience within the Building Stock
Digital documentation has become integral to the preservation, analysis and communication of historical sites. New platforms are now being developed that involve complex 3D models and allow the analysis of spatial data. These include procedural modelling, a technique that enables the rapid development of âdynamicâ 3D environments, and generation of simulations for entire cities, resulting in low cost, high resolution 3D city models. Though procedural modelling has been used in the context of archaeology to ârecreateâ cities at specific historic time points, the use of historical data in the development of rule-based procedural models for current cities has been little explored. Here, we test the extent to which construction age data, historical building regulations and architectural knowledge can be used in the generation of procedural rules, and the level of detail and potential impact that these models may have. Rather than creating an accurate representation of the city, we instead seek to simulate the way in which urban areas are likely to behave under certain conditions, in order to test what-if? planning scenarios. This allows us to explore more flexible ways of digitally âcreatingâ cities, past and present, and to gain insights into underlying ârulesâ that govern their physical form
Private Sector and Waste Management in Delhi: A Political Economy Perspective
Due to their size and rapid growth, large cities in developing countries are increasingly challenged by burgeoning waste generation. Waste management, however, has traditionally provided employment opportunities to the many urban poor in the informal sector. These traditional models, working largely in parallel with state?led interventions, are under pressure because they fail to address the waste management crisis. This failure, coupled with the lack of capacities of local governments, has paved the way for formal private sector participation. We examine the case of Delhi where a complex interplay of competing approaches have accompanied efforts of urban local bodies, civil society and the private sector (informal and formal) at finding a sustainable working solution. Our analysis of the complex relationship within the private sector players, and between private and public actors, provides novel insights into potential contribution of publicâprivate partnerships for effective waste management in developing countries
Modeling the Effect of Urbanization on Climate and Dust Generation Over Desert Cities
abstract: Understanding and predicting climate changes at the urban scale have been an important yet challenging problem in environmental engineering. The lack of reliable long-term observations at the urban scale makes it difficult to even assess past climate changes. Numerical modeling plays an important role in filling the gap of observation and predicting future changes. Numerical studies on the climatic effect of desert urbanization have focused on basic meteorological fields such as temperature and wind. For desert cities, urban expansion can lead to substantial changes in the local production of wind-blown dust, which have implications for air quality and public health. This study expands the existing framework of numerical simulation for desert urbanization to include the computation of dust generation related to urban land-use changes. This is accomplished by connecting a suite of numerical models, including a meso-scale meteorological model, a land-surface model, an urban canopy model, and a turbulence model, to produce the key parameters that control the surface fluxes of wind-blown dust. Those models generate the near-surface turbulence intensity, soil moisture, and land-surface properties, which are used to determine the dust fluxes from a set of laboratory-based empirical formulas. This framework is applied to a series of simulations for the desert city of Erbil across a period of rapid urbanization. The changes in surface dust fluxes associated with urbanization are quantified. An analysis of the model output further reveals the dependence of surface dust fluxes on local meteorological conditions. Future applications of the models to environmental prediction are discussed.Dissertation/ThesisDoctoral Dissertation Mechanical Engineering 201
Final report: Workshop on: Integrating electric mobility systems with the grid infrastructure
EXECUTIVE SUMMARY:
This document is a report on the workshop entitled âIntegrating Electric Mobility
Systems with the Grid Infrastructureâ which was held at Boston University on November 6-7
with the sponsorship of the Sloan Foundation. Its objective was to bring together researchers
and technical leaders from academia, industry, and government in order to set a short and longterm research agenda regarding the future of mobility and the ability of electric utilities to meet
the needs of a highway transportation system powered primarily by electricity. The report is a
summary of their insights based on workshop presentations and discussions. The list of
participants and detailed Workshop program are provided in Appendices 1 and 2.
Public and private decisions made in the coming decade will direct profound changes in
the way people and goods are moved and the ability of clean energy sources â primarily
delivered in the form of electricity â to power these new systems. Decisions need to be made
quickly because of rapid advances in technology, and the growing recognition that meeting
climate goals requires rapid and dramatic action. The blunt fact is, however, that the pace of
innovation, and the range of business models that can be built around these innovations, has
grown at a rate that has outstripped our ability to clearly understand the choices that must be
made or estimate the consequences of these choices. The group of people assembled for this
Workshop are uniquely qualified to understand the options that are opening both in the future of
mobility and the ability of electric utilities to meet the needs of a highway transportation system
powered primarily by electricity. They were asked both to explain what is known about the
choices we face and to define the research issues most urgently needed to help public and
private decision-makers choose wisely. This report is a summary of their insights based on
workshop presentations and discussions.
New communication and data analysis tools have profoundly changed the definition of
what is technologically possible. Cell phones have put powerful computers, communication
devices, and position locators into the pockets and purses of most Americans making it possible
for Uber, Lyft and other Transportation Network Companies to deliver on-demand mobility
services. But these technologies, as well as technologies for pricing access to congested
roads, also open many other possibilities for shared mobility services â both public and private â
that could cut costs and travel time by reducing congestion. Options would be greatly expanded
if fully autonomous vehicles become available. These new business models would also affect
options for charging electric vehicles. It is unclear, however, how to optimize charging
(minimizing congestion on the electric grid) without increasing congestion on the roads or
creating significant problems for the power system that supports such charging capacity.
With so much in flux, many uncertainties cloud our vision of the future. The way new
mobility services will reshape the number, length of trips, and the choice of electric vehicle
charging systems and constraints on charging, and many other important behavioral issues are
critical to this future but remain largely unknown. The challenge at hand is to define plausible
future structures of electric grids and mobility systems, and anticipate the direct and indirect
impacts of the changes involved. These insights can provide tools essential for effective private ... [TRUNCATED]Workshop funded by the Alfred P. Sloan Foundatio
Simulating city growth by using the cellular automata algorithm
The objective of this thesis is to develop and implement a Cellular Automata
(CA) algorithm to simulate urban growth process. It attempts to satisfy the
need to predict the future shape of a city, the way land uses sprawl in the
surroundings of that city and its population. Salonica city in Greece is
selected as a case study to simulate its urban growth. Cellular automaton
(CA) based models are increasingly used to investigate cities and urban
systems. Sprawling cities may be considered as complex adaptive systems,
and this warrants use of methodology that can accommodate the space-time
dynamics of many interacting entities. Automata tools are well-suited for
representation of such systems. By means of illustrating this point, the
development of a model for simulating the sprawl of land uses such as
commercial and residential and calculating the population who will reside in
the city is discussed
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Towards Rapid Generation and Visualisation of Large 3D Urban Landscapes for Mobile Device Navigation
In this paper a procedural 3D modelling solution for mobile devices is presented based on scripting algorithms allowing for both the automatic and also semi-automatic creation of photorealistic quality virtual urban content. The combination of aerial images, GIS data, 2D ground maps and terrestrial photographs as input data coupled with a user-friendly customized interface permits the automatic and interactive generation of large-scale, accurate, georeferenced and fully-textured 3D virtual city content, content that can be specially optimized for use with mobile devices but also with navigational tasks in mind. Furthermore, a user-centred mobile virtual reality (VR) visualisation and interaction tool operating on PDAs (Personal Digital Assistants) for pedestrian navigation is also discussed. Via this engine, the import and display of various navigational file formats (2D and 3D) is supported, including a comprehensive front-end user-friendly graphical user interface providing immersive virtual 3D navigation
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A roadmap for China to peak carbon dioxide emissions and achieve a 20% share of non-fossil fuels in primary energy by 2030
As part of its Paris Agreement commitment, China pledged to peak carbon dioxide (CO2) emissions around 2030, striving to peak earlier, and to increase the non-fossil share of primary energy to 20% by 2030. Yet by the end of 2017, China emitted 28% of the world's energy-related CO2 emissions, 76% of which were from coal use. How China can reinvent its energy economy cost-effectively while still achieving its commitments was the focus of a three-year joint research project completed in September 2016. Overall, this analysis found that if China follows a pathway in which it aggressively adopts all cost-effective energy efficiency and CO2 emission reduction technologies while also aggressively moving away from fossil fuels to renewable and other non-fossil resources, it is possible to not only meet its Paris Agreement Nationally Determined Contribution (NDC) commitments, but also to reduce its 2050 CO2 emissions to a level that is 42% below the country's 2010 CO2 emissions. While numerous barriers exist that will need to be addressed through effective policies and programs in order to realize these potential energy use and emissions reductions, there are also significant local environmental (e.g., air quality), national and global environmental (e.g., mitigation of climate change), human health, and other unquantified benefits that will be realized if this pathway is pursued in China
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