How bicycling sharing system usage is affected by land use and urban form: analysis from system and user perspectives

There is a rapid growth of bicycle-sharing systems (BSS) around the world. Cities are supporting these systems as a more sustainable transport mode for short trips. Given the relatively recent adoption of BSS, there is substantial interest in understanding how these systems impact urban transportation. In this paper, we examine the functioning of the hugely successful New York City CitiBike system. We focus on the interaction of BSS with land-use and built environment attributes and the influence of weather condition and temporal characteristics on BSS usage. Towards this end, CitiBike system is analyzed along two dimensions: (1) at the system level, we examine the hourly station level arrival and departure rates using a linear mixed model and (2) at the trip level, we investigate users’ destination station choice preferences after they pick up a bicycle from a station employing a random utility maximization approach. The results highlight clear spatial and temporal differences in the usage of CitiBike by users with annual membership and users with temporary passes. Overall, our analysis provides a framework and useful insights for cities that are planning to install a new bicycle sharing system or to expand an existing syste

How Bicycling Sharing System Usage is Affected by Land Use and Urban Form: Analysis from System and User Perspectives

There is a rapid growth of bicycle-sharing systems (BSS) around the world. Cities are supporting these systems as a more sustainable transport mode for short trips. Given the relatively recent adoption of BSS, there is substantial interest in understanding how these systems impact urban transportation. In this paper, we examine the functioning of the hugely successful New York City CitiBike system. We focus on the interaction of BSS with land-use and built environment attributes and the influence of weather condition and temporal characteristics on BSS usage. Towards this end, CitiBike system is analyzed along two dimensions: (1) at the system level, we examine the hourly station level arrival and departure rates using a linear mixed model and (2) at the trip level, we investigate users\u27 destination station choice preferences after they pick up a bicycle from a station employing a random utility maximization approach. The results highlight clear spatial and temporal differences in the usage of CitiBike by users with annual membership and users with temporary passes. Overall, our analysis provides a framework and useful insights for cities that are planning to install a new bicycle sharing system or to expand an existing system

Modelling cellphone trace travel mode with neural networks using transit smartcard and home interview survey data

This study proposes a framework to impute travel mode for trips identified from cellphone traces by developing a deep neural network model. In our framework, we use the trips from a home interview survey and transit smartcard data, for which the travel mode is known, to create a set of artificial pseudo-cellphone traces. The generated artificial pseudo-cellphone traces with known mode are then used to train a deep neural network classifier. We further apply the trained model to infer travel modes for the cellphone traces from cellular network data. The empirical case study region is Montevideo, Uruguay, where high-quality data are available for all three types of data used in the analysis: a large dataset of cellphone traces, a large dataset of public transit smartcard transactions, and a small household travel survey. The results can be used to create an enhanced representation of origin-destination trip-making in the region by time of day and travel mode

Sonographic and functional characteristics of thyroid nodules in a population of adult people in Isfahan

Wstęp: Celem badania była ocena cech sonograficznych zmian ogniskowych tarczycy u mieszkańców Isfahanu, obszaru w cenralnym Iranie, który wcześniej charakteryzował się niedoborem jodu. Materiał i metody: W przekrojowym badaniu przeprowadzonym w 2006 roku wybrano próbę liczącą 2523 dorosłych osób (wiek > 20 lat) metodą wielostopniowego losowania grupowego. Spośród tej grupy, 263 ochotników poddano badaniom sonograficznym. Badanie tarczycy przeprowadzili doświadczeni specjaliści w zakresie ultrasonografii. Ponadto oznaczono stężenia T3, T4, T3RU, TSH, TPO Ab i Tg Ab w surowicy oraz wydalanie jodu z moczem. Wyniki: Kobiety stanowiły 46% grupy poddanej badaniom sonograficznym (n = 263). Średnia wieku wynosiła 35,5 lat (zakres 20-64 lat). Mediana stężenia jodu w moczu wynosiła 19.4 μg/dl. Obecność zmian ogniskowych tarczycy wykazano w badaniu sonograficznym u 22,4% osób z badanej grupy; u 30% kobiet i 16,3% mężczyzn (OR = 2,2; p = 0,01). Częstość występowania zmian ogniskowych tarczycy zwiększała się z wiekiem (p = 0,006). Zmiany ogniskowe tarczycy występowały częściej u osób z niedoczynnością tarczycy niż w grupie z eutyreozą (35,1% v. 20,5%, OR = 2,1; p = 0,04). Nie stwierdzono korelacji między stężeniem jodu w moczu ani stężeniem autoprzeciwciał a występowaniem zmian ogniskowych tarczycy w badaniu sonograficznym. Wnioski: Częstość występowania zmian ogniskowych tarczycy oceniana na podstawie wyników badania sonograficznego jest nadal duża w badanej populacji, mimo prawidłowego stężenia jodu w moczu. (Endokrynol Pol 2010; 61 (2): 188-191)Introduction: The aim of this study was to investigate the current status of sonographic characteristics of thyroid nodules in Isfahan, a previously iodine deficient area in central Iran. Material and methods: In a cross-sectional study conducted in 2006, 2523 adult people (age > 20 years) were selected by a multistage clustering sampling method. Of these people, 263 volunteered persons were underwent sonographic evaluation. Thyroid examination was done by two expert sonographers. Serum T3, T3, T3RU, TSH, TPO Ab and Tg Ab, and urinary iodine were measured. Results: Forty-six per cent of the 263 people were women. Their mean age was 35.5 years with a range of 20-64 years. Median urinary iodine was 19.4 μg/dL. The prevalence of thyroid nodules on sonography was 22.4% in the whole group; 30% in women and 16.3% in men (OR = 2.2, P = 0.01). The prevalence of thyroid nodules increased with age (P = 0.006). The prevalence of thyroid nodules was higher in hypothyroid people than in euthyroid people (35.1% v. 20.5%, OR = 2.1, P = 0.04). Neither urinary iodine nor autoantibody concentrations correlated with the prevalence of thyroid nodules in sonography. Conclusions: The prevalence of thyroid nodule by sonography is still high despite relatively normal urinary iodine in this population. (Pol J Endocrinol 2010; 61 (2): 188-191

How land-use and urban form impact bicycle flows: Evidence from the bicycle-sharing system (BIXI) in Montreal

ABSTRACT Installed in 2009, BIXI is the first major public bicycle-sharing system in Montreal, Canada. The BIXI system has been a success, accounting for more than one million trips annually. This success has increased the interest in exploring the factors affecting bicycle-sharing flows and usage. Using data compiled as minute-by-minute readings of bicycle availability at all the stations of the BIXI system between April and August 2012, this study contributes to the literature on bicycle-sharing. We examine the influence of meteorological data, temporal characteristics, bicycle infrastructure, land use and built environment attributes on arrival and departure flows at the station level using a multilevel approach to statistical modeling, which could easily be applied to other regions. The findings allow us to identify factors contributing to increased usage of bicycle-sharing in Montreal and to provide recommendations pertaining to station size and location decisions. The developed methodology and findings can be of benefit to city planners and engineers who are designing or modifying bicycle-sharing systems with the goal of maximizing usage and availability

Impacts of COVID-19 on the Energy System

This Briefing Paper explores the impact the COVID-19 pandemic had on the UK’s energy sector over the course of the first government-mandated national lockdown that began on 23 March 2020. Research from several aspects of the Integrated Development of Low-carbon Energy Systems (IDLES) programme at Imperial College London is presented in one overarching paper. The main aim is to determine what lessons can be learnt from that lockdown period, given the unique set of challenges it presented in our daily lives and the changes it brought about in energy demand, supply, and use. Valuable insights are gained into how working-from-home policies, electric vehicles, and low-carbon grids can be implemented, incentivised, and managed effectively

Theory and Development of Near-field Plates.

The widespread use of the electromagnetic near field, in applications ranging from high resolution imaging devices to wireless power transfer systems, has called for focusing devices with higher resolutions and larger focal lengths. This demand, however, faces a major obstacle: the diffraction limit. Due to this limit, subwavelength resolutions are only possible at near-field distances. A novel solution is proposed for overcoming the diffraction limit: near-field plates (NFPs). NFPs are non-periodically patterned surfaces that can form desired subwavelength patterns at specified near-field distances. They are simple to fabricate, robust to inherent losses, and allow the near field pattern to be stipulated. Given these advantages, they show great promise as a simple and effective method for tailoring the electromagnetic near field. In this thesis, the first reported NFP is introduced and its operation is analytically studied. The NFP concept is then advanced through several phases, addressing a major issue in each phase. NFPs suitable for practical applications are introduced, and their design and operation are described. Their ability to tailor the electromagnetic near field is verified through full-wave simulations and experiments. Finally, application areas of NFPs such as near-field probing and imaging, biomedical devices, and wireless power transfer systems are discussed.PhDElectrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/97828/1/smfimani_1.pd

Understanding bicycle sharing systems: user and system insights from three cities in North America

A bicycle-sharing system (BSS) is a public transportation service in which bicycles are available for renting within a service area for a short period of time. Many benefits of BSS have led to their growth around the world recently. However, due to the relatively recent adoption of BSS, there is very little research exploring how people consider these systems within the existing transportation alternatives. Further, it is of substantial interest for transportation professionals to identify contributing factors to the BSS demand. The objective of this dissertation is to examine BSS from both system and user perspectives to provide useful insights on how these innovative public systems influence the urban transportation. The BSS analyzed are from three North American cities: Montreal, Chicago, and New York City. Within the systems perspective, the dissertation addresses three research questions. First, the research quantifies the influence of meteorological data, temporal characteristics, bicycle infrastructure, land use and built environment attributes on BSS usage at the station level using multilevel linear mixed modeling approach. Second, the dissertation explores the presence of spatial and temporal correlations across BSS usage dimensions by developing panel spatial error and panel spatial lag models. Finally, the dissertation examines the influence of BSS infrastructure installation decision endogeneity on the "true" impact of BSS infrastructure on BSS usage through the development of a joint multi-level mixed model.In terms of user perspective, the dissertation studies BSS behavior at a trip level to examine bicyclists' destination preferences. Specifically, the decision process involved in identifying destination locations after picking up a bicycle at a BSS station is studied. The analyses are presented in two chapters. First, a random utility maximization approach is developed that assumes an individual who picks up a bicycle at one of the stations makes destination station choice based on a host of attributes including individual's characteristics, time of the day, and destination station attributes. Second, in order to account for BSS trips heterogeneity, an advanced model that probabilistically assigns trips to different segments and estimates segment-specific destination choice models for each segment is proposed. This model can also consider the effect of fixed attributes across destinations such as users or origins attributes in the decision process.The dissertation also investigates the influence of sample size on system and user perspectives models by evaluating the impact of sample size on model estimates, inference measures, and predictive performance. The analyses show that the impact of sample size on parameters estimated is stronger than that of the impact on prediction performance. Overall, the dissertation results present several interesting findings including the distinct travel behavior of annual members compared to users with temporary passes, the use of BSS for the daily commute to and from work, and the distinguished travel patterns for BSS in weekends. The results also highlight the importance of BSS system attributes such as stations' capacity and location.L'objectif principal de cette dissertation est d'examiner les SVLS d'un point de vue systémique, ainsi que de la perspective des usagers, afin de contribuer à notre compréhension de ces systèmes innovateurs, et comment ils influencent nos systèmes de transports urbains. Cette dissertation examine les SVLS de trois villes Nord-Américaines : BIXI à Montréal, au Canada; DIVVY à Chicago, et CitiBike à New York aux États-Unis.D'un point de vue systémique, cette dissertation se penche sur trois questions. Premièrement, ce document quantifie l'influence de données météorologiques, temporelles, d'infrastructure cyclable, de l'utilisation du territoire, et de l'environnement urbain sur l'utilisation des SVLS, à travers l'usage de modèles linéaires multi-niveaux mixtes. Deuxièmement, la présence de corrélations spatio-temporelles dans l'usage des SVLS est investiguée grâce au développement de modèles panels d'erreur spatiale et de délai spatial. Troisième, nous explorons la présence et l'influence de l'endogénéité de la décision d'installer de l'infrastructure de SVLS sur le « véritable » impact de l'infrastructure de SVLS sur l'utilisation des SVLS. En termes de perspective de l'usager, cette dissertation étudie le comportement des SVLS au niveau de trajets individuels afin d'examiner les choix de destination des cyclistes. Spécifiquement, le processus de décision impliqué dans le choix d'une destination après avoir choisi un vélo à une station de SVLS est étudié. Cette dissertation investigue aussi l'influence de la taille des échantillons sur les perspectives d'usager et du système. Spécifiquement, une évaluation systématique de l'impact de la taille des échantillons sur les résultats des modèles, des mesures d'inférence, et la capacité de prédiction est proposée