San Francisco | EPFL Graph Search

San Francisco (ˌsæn_fɹənˈsɪskoʊ; ), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the fourth most populous city in California, with 808,437 residents, and the 17th most populous city in the United States . The city covers a land area of at the end of the San Francisco Peninsula, making it the second most densely populated large U.S. city after New York City and the fifth-most densely populated U.S. county, behind only four of the five New York City boroughs. Among the 91 U.S. cities proper with over 250,000 residents, San Francisco was ranked first by per capita income and sixth by aggregate income . Colloquial nicknames for San Francisco include Frisco, San Fran, The , and SF. San Francisco was founded on June 29, 1776, when settlers from New Spain established the Presidio of San Francisco at the Golden Gate, and the Mission San Francisco de Asís a

Du savetier au financier: la famille Borel, de Neuchâtel à San Francisco

The Borel Family From Neuchâtel to San Francisco : From shoemaker to banker Did you know that the Cable Car was owned by Swiss citizens? BACKTRACKING : PRIVATE FINANCING OF PUBLIC METROPOLITAN INFRASTRUCTURES Executive Summary: Did you know that one of San Francisco most famous fixtures, the Cable car, was owned by Swiss citizens? Through this detailed study of the Borel family, and its business and investment plans we will observe an example of private financing of public metropolitan infrastructures in the 19th Century and see if it can teach us lessons for tomorrow’s needs? TOPICS Looking at today’s infrastructures, one does not always remember how much work contracting firms had to accomplish in order to produce our contemporary standard of urban comfort . What is to be said of yesterday’s planners or engineers and the credit they deserve? We often hear stories of local events brought to epic proportions, but who are the responsible players who really proved the feasibility of regional infrastructures? Who actually did support, sponsor or finance such achievements? The present study is a trial to propose a new view over such apparently hidden business phenomenons. This research shows us an inspiring case-study of local entrepreneurs who gather key success-factors. The author concentrates on the economic aspect of infrastructure financing to which modern metropolitan society owes its specific urban growth. Contemporary challenges such as job creation, globalisation, technology transfer and local economic development are all interconnected to metropolitan development. XIXTH CENTURY METROPOLITAN INFRASTRUCTURES FINANCING Le Temps, 30th July 1998, D. Masmejan : «Alfred Borel, Auguste’s elder son, enters the finance world. He meets an extraordinary businessman fate. His understanding of the economic impact of the Californian Gold Rush allows him to seize the opportunity of the westward American expansionism. He sails to San Francisco in 1855 where he is the founder of the «Alfred Borel & Company», followed in 1856 by a Mortgage fund (the “Caisse Hypothécaire” bank). The same year sees the foundation of Credit Suisse in Zurich. Alfred Borel investment bank participates in very important infrastructure projects in California and elsewhere in the second half of the XIXth century. At first, its investment into the worldwide famous San Francisco Cable Car is marginal and then becomes overwhelming. Other investments include the “Los Angeles Railway Company” or the “United Railroad Company”, the San Francisco Waterworks, other banks and real estate.» DETAILED RESEARCH ALLOWING TO UNDERSTAND FINANCIAL DECISION MAKING The author reviews financial decision-making through personal correspondence and private accounting in some of those completely documented yearly archives. The «sixth Switzerland» well-connected to the Presbyterian «Huguenot International» cosmopolitan network leads us to detailed research and discoveries. The accounting of 1866 to 1884 goes through the 3rd and 4th San Francisco City real estate crises that the mortgage bankers Borel brothers had to endure. Alfred Borel faced the 2nd Californian real estate crisis (which resulted from the first loss of public interest in gold mines in the years 1854-1858). Then he went back to Switzerland after the death of his father and uncles in order to reconstitute the Swiss end of the pipe connecting his bank’s investors to the Borel family network. He left duty of the day-to-day San Francisco business to his younger brother Antoine after having set up asset management rules. Together both brothers explored new ways of diversifying the investment of the funds they are managing and place them into infrastructures networks. Taking shares «upstream» into equipment industries (for instance the wire works delivering the precise traction rope of cable cars) or other real estate assets, allowed them to guarantee superior interests payments to European investors or creditors in comparison with other financial markets. This anticyclical economic strategy set up their financial success that occurred during the 5th local economic recession, which coincides with the beginning of the big worldwide Victorian economic crisis (1880-1895). UNIQUE SPECIFICITY OF THIS RESEARCH This research process is rarely accomplished in engineering and architecture schools, construction and infrastructures institutes or research centers. The integrity of construction professionals precludes their questioning « where does the whole process originate from?». Builders ultimately considered themselves as «honest craftsmen» that have to dedicate their energy and resources to the proper technical execution of the clients wishes and orders. Customers duty is then to write the project’s specifications and thus to initiate its process. The author of this case-study demonstrates the feasibility of comparisons between similar structural change periods in the XIXth century and the years 1990-2000. Hence, a new theme of interdisciplinary studies for engineers could be implemented by promoting this systemic approach between urban infrastructure financiers, suppliers and users. Last but not least, the insider observations and outsider revelations which are featured in this work are seldom considered in an engineering historical approach. It is not often that an author with a contemporary outsider vision has access to family archives that entirely document bicentennial confidential banker correspondence.

EPFL1999

Spatial and Temporal Analysis of Congestion in Urban Transportation Networks

Yuxuan Ji

Research on congestion and propagation in large urban city networks has been mainly based on microsimulations of link-level traffic dynamics. However, both the unpredictability of travel behaviors and high complexity of accurate physical modeling remain challenging and simulation results may be far time consuming and not realistic. It has been recently shown that amacroscopic fundamental diagram (MFD) linking space-mean network flow, density and speed exists in the urban transportation networks under some conditions. An MFD is further well defined if the network is homogeneous with links of similar properties. This collective behavior concept can also be utilized to introduce simple control strategies to improve mobility in homogeneous city centers without the need for details in individual links. However many real urban transportation networks are heterogeneous with different levels of congestion. In order to study the existence of MFD and the feasibility of simple control strategies to improve network performance in heterogeneously congested networks, this thesis mainly focuses on three issues: (1) static partitioning of traffic networks, (2) congestion propagation and dynamic partitioning, and (3) the effect of network structure on congestion propagation. Firstly, we study the static partitioning of transportation networks based on the spatial features of congestion during a specific time period. A partitioning mechanism which consists of three consecutive algorithms, is designed to minimize the variance of link densities while maintaining the spatial compactness of the clusters. Secondly we explore the dynamics of traffic conditions and thus the corresponding dynamic partitioning scheme. We reveal the hidden information during the process of congestion formation by exploring empirical data from large-scale urban networks. Specifically, we aim at studying the spatiotemporal relation of congested links, observing congestion propagation from an macroscopic perspective, and finally identifying critical congestion regimes to aid the design of peripheral control strategies. Finally, we study the formation of traffic congestion by simulation in large scale cities with different network structures. A parsimonious model of congestion propagation is developed and validated by real data in San Francisco in US and Shenzhen in China (20000 taxis with 30 million logs per day). The effect of network structure on congestion propagation is investigated by simulations conducted in a variety of network structures.

EPFL2014

An urban ecohydrological model to quantify the effect of vegetation on urban climate and hydrology (UT&C v1.0)

Paolo Burlando, Matthias Roth

Increasing urbanization is likely to intensify the urban heat island effect, decrease outdoor thermal comfort, and enhance runoff generation in cities. Urban green spaces are often proposed as a mitigation strategy to counteract these adverse effects, and many recent developments of urban climate models focus on the inclusion of green and blue infrastructure to inform urban planning. However, many models still lack the ability to account for different plant types and oversimplify the interactions between the built environment, vegetation, and hydrology. In this study, we present an urban ecohydrological model, Urban Tethys-Chloris (UT&C), that combines principles of ecosystem modelling with an urban canopy scheme accounting for the biophysical and ecophysiological characteristics of roof vegetation, ground vegetation, and urban trees. UT&C is a fully coupled energy and water balance model that calculates 2 m air temperature, 2 m humidity, and surface temperatures based on the infinite urban canyon approach. It further calculates the urban hydrological fluxes in the absence of snow, including transpiration as a function of plant photosynthesis. Hence, UT&C accounts for the effects of different plant types on the urban climate and hydrology, as well as the effects of the urban environment on plant well-being and performance. UT&C performs well when compared against energy flux measurements of eddy-covariance towers located in three cities in different climates (Singapore, Melbourne, and Phoenix). A sensitivity analysis, performed as a proof of concept for the city of Singapore, shows a mean decrease in 2 m air temperature of 1.1 ∘C for fully grass-covered ground, 0.2 ∘C for high values of leaf area index (LAI), and 0.3 ∘C for high values of Vc,max (an expression of photosynthetic capacity). These reductions in temperature were combined with a simultaneous increase in relative humidity by 6.5 %, 2.1 %, and 1.6 %, for fully grass-covered ground, high values of LAI, and high values of Vc,max, respectively. Furthermore, the increase of pervious vegetated ground is able to significantly reduce surface runoff.

2020