Heinen, E
2011-01-01
Cycling is cheaper, healthier and in urban environments often faster than other transport modes. Nevertheless, even at short distances, many individuals do not cycle. This thesis aims to explain why commuters vary in their decision to bicycle. Results indicate that the individual (day-to-day) choice to commute by bicycle is affected by personal attitudes towards cycling to work, social norms, work situation, weather conditions and trip characteristics. Additionally, this thesis provides evide...
Commuter Transport Mode Choice and Typologies in the Bicycle City Copenhagen
Olesen, Anne Vingaard; Kjems, Erik; Reinau, Kristian Hegner;
2016-01-01
“Bicycle Cities” such as Copenhagen can serve as role models: how far can we push the commuter modal shares in the direction of more sustainable transport? This paper presents a study that aims to give a state-of-the-art picture of a Copenhagen that provides wide cycling highways and the political...... will to provide for even more bicycles. We found a ratio of 1:1 of car to bicycle in the greater Copenhagen area, whereas a ratio 2:5 of cars to bicycles existed in the central city - in terms of commuters who both live and work in the city center and who thus have an effective choice between modes due...
Tertiary Student Attitudes to Bicycle Commuting in a Regional Australian University
Whannell, Patricia; Whannell, Robert; White, Richard
2012-01-01
Purpose: The purpose of this paper is to provide executive management at a regional university with empirical data to justify, or otherwise, a substantial outlay of funds to support bicycle commuting as a viable strategy for the reduction of traffic congestion. Design/methodology/approach: A custom designed questionnaire was completed by 270…
Understanding adolescents' intentions to commute by car or bicycle as adults
Sigurdardottir, Sigrun Birna; Kaplan, Sigal; Møller, Mette;
2013-01-01
This study focuses on the intentions of adolescents to commute by car or bicycle as adults. The behavioral model is based on intrapersonal and interpersonal constructs from the theory of planned behavior extended to include constructs from the institutional, community and policy domains. Data from...... a survey among Danish adolescents is analyzed. It is found that car use intentions are related to positive car passenger experience, general interest in cars, and car ownership norms, and are negatively related to willingness to accept car restrictions and perceived lack of behavioral control. Cycling...... intentions are related to positive cycling experience, willingness to accept car restrictions, negative attitudes towards cars, and bicycle-oriented future vision, and are negatively related to car ownership norms. Attitudinal constructs are related to individual characteristics, such as gender, residential...
A portable air sampling system has been used to assess exposures to various substances while commuting by bicycle in an urban area. The major source of pollutants in this situation is motor vehicle exhaust emissions. Carbon monoxide, measured by electrochemical detection, was found at peak concentrations in excess of 62 ppm, with mean values over 16 individual 35-mm journeys being 10.5 ppm. Respirable suspended particulates, averaged over each journey period, were found at higher concentrations (mean 130 μg m-3) than would be expected in indoor situations. Mean exposure to benzene (at 56 μg m-3) and other aromatic volatile organic compounds was also relatively high. The influence of wind conditions on exposure was found to be significant. Commuting exposures to carbon monoxide, respirable suspended particulates, and aromatic VOCs were found to be higher than exposures in a busy high street and on common parkland
‘We are the future’: understanding adolescents’ intentions to commute by car or bicycle as adults
Sigurdardottir, Sigrun Birna; Kaplan, Sigal; Møller, Mette;
This study focuses on the intentions of adolescents to commute by car or bicycle as adults, as key elements towards promoting societal transition towards sustainable modes. The behavioral model is based on the theory of planned behavior combined with positive current travel experience, willingness...... to accept car restrictions, transport-related future vision, environmental concern and social influence. Data are retrieved from a survey among 15-years old Danish adolescents, and are analyzed with structural equation models. Results show: (i) car use intentions are positively related to positive car...... passenger experience, general interest in cars, and car-ownership norms, and are negatively related to willingness to accept car restrictions and perceived lack of behavioral control; (ii) cycling intentions are positively related to positive cycling experience, willingness to accept car restrictions...
Understanding adolescents' intentions to commute by car or bicycle as adults
Sigurdardottir, Sigrun Birna; Kaplan, Sigal; Møller, Mette; Teasdale, Thomas William
2013-01-01
. Cycling intentions are related to positive cycling experience, willingness to accept car restrictions, negative attitudes towards cars, and bicycle-oriented future vision, and are negatively related to car ownership norms. Attitudinal constructs are related to individual characteristics, such as gender...
2013-01-01
Background Bicycle commuting in an urban environment of high air pollution is known to be a potential health risk, especially for susceptible individuals. While risk management strategies aimed to reduce exposure to motorised traffic emissions have been suggested, only limited studies have assessed the utility of such strategies in real-world circumstances. Objectives The potential to lower exposure to ultrafine particles (UFP; < 0.1 μm) during bicycle commuting by reducing proximity to motorised traffic was investigated with real-time air pollution and intermittent acute inflammatory measurements in healthy individuals using their typical higher proximity, and an alternative lower proximity, bicycle commute route. Methods Thirty-five healthy adults (mean ± SD: age = 39 ± 11 yr; 29% female) completed two return trips, one each in the condition of their typical route (HIGH) and a pre-determined alternative route of lower proximity to motorised traffic (LOW); proximity being determined by the proportion of on-road cycle paths. Particle number concentration (PNC) and diameter (PD) were monitored in-commute in real-time. Acute inflammatory indices of respiratory symptoms (as a scalar of frequency from very low to very high / 1 to 5), lung function and spontaneous sputum (for inflammatory cell analyses) were collected immediately pre-commute, and immediately and three hours post-commute. Results In the condition of LOW, compared to in the condition of HIGH, there was a significant decrease in mean PNC (1.91 x e4 ± 0.93 × e4 ppcc vs. 2.95 × e4 ± 1.50 × e4 ppcc; p ≤ 0.001), and the mean frequency of in-commute offensive odour detection (2.1 vs. 2.8; p = 0.019), dust and soot observation (1.7 vs. 2.3; p = 0.038) and nasopharyngeal irritation (1.5 vs. 1.9; p = 0.007). There were no significant differences between LOW and HIGH in the commute distance and duration (12.8 ± 7.1 vs. 12.0 ± 6.9 km and 44 ± 17 vs. 42 ± 17 min, respectively), or other indices of
A Survey on Subway & Foldable Bicycle Commuting: A Case Study in Nanjing%地铁+折叠自行车通勤出行调查——以南京市为例
梁晶; 石飞; 祁毅; 陈曦
2011-01-01
为研究地铁+折叠自行车通勤方式的效果,以南京地铁为例对使用折叠自行车的乘客和普通乘客进行了现场调查和问卷调查.分析相关数据发现:地铁+折叠自行车的通勤方式在南京已获得了较好的实践及市民的广泛认可；与私人小汽车、公共汽车、自行车、地铁+步行等交通方式相比,更加节约出行时间和出行成本,也更加低碳.随着地铁线网的加密,地铁+折叠自行车通勤方式的服务范围可达主城区总面积的92％.为更好地推广这种健康环保的出行方式、鼓励更多的人使用公共交通,从城市及交通规划、设施配置、宣传引导三个层面提出了改进建议.%In order to study the effect of subway plus foldable bicycle commuting, a survey was conducted on subway passengers with and without foldable bicycle through questionnaires and interviews in Nanjing city subway. The results show that subway plus foldable bicycle has been recognized and accepted as a practical commuting travel mode by citizens. Comparing with other travel modes such as private car, bus, bicycle, and subway & walking, the combination of subway and foldable bicycle can reduce travel time and cost, and decrease carbon emission. With the subway network expansion, the subway & bicycle commuting travel can cover 92% Nanjing main urban areas. To better promote this health and environmental friendly travel mode, improvements in urban planning, transportation facility development and public policy are proposed by the paper to encourage high utilization of public transportation.
Exercise bicycle for accumulator charging
Nekvapil, Jan
2014-01-01
Bachelor thesis is about possible solution construction of exercise bicycle with electric part working as a electric source. The first part of document introduces readers to issues about lead acid accumulators and charging, electronically commutated motors and electric converters. The second part shows potential solving constitution of exercise bicycle and we choose components and devices. EC motor will be connected with exercise bicycle by chain transmission. Transfer energy is realized thro...
Walker, Ian; Garrard, Ian; Jowitt, Felicity
2014-03-01
This study looked at whether drivers overtaking a bicyclist changed the proximities of their passes in response to the level of experience and skill signalled by the bicyclist's appearance. Seven outfits were tested, ranging from a stereotypical sport rider's outfit, portraying high experience and skill, to a vest with 'novice cyclist' printed on the back, portraying low experience. A high-visibility bicycling jacket was also used, as were two commercially available safety vests, one featuring a prominent mention of the word 'police' and a warning that the rider was video-recording their journey, and one modelled after a police officer's jacket but with a letter changed so it read 'POLITE'. An ultrasonic distance sensor recorded the space left by vehicles passing the bicyclist on a regular commuting route. 5690 data points fulfilled the criteria for the study and were included in the analyses. The only outfit associated with a significant change in mean passing proximities was the police/video-recording jacket. Contrary to predictions, drivers treated the sports outfit and the 'novice cyclist' outfit equivalently, suggesting they do not adjust overtaking proximity as a function of a rider's perceived experience. Notably, whilst some outfits seemed to discourage motorists from passing within 1m of the rider, approximately 1-2% of overtakes came within 50 cm no matter what outfit was worn. This suggests there is little riders can do, by altering their appearance, to prevent the very closest overtakes; it is suggested that infrastructural, educational or legal measures are more promising for preventing drivers from passing extremely close to bicyclists. PMID:24333770
Revitalization of Cycling in a Former Bicycle Kingdom: Beijing
Zhao, Chunli; Carstensen, Trine Agervig; Olafsson, Anton Stahl;
This paper scrutinizes and analyses the relevant historical policy documents chronologically - from the 1960s to the present - in order to figure out the potentials of revitalizing the bicycle mode share in Beijing. Firstly, we targeted two top-drawer conflicts of the bicycle use, which are travel......- or commuting distance and motorised vehicle-oriented urban development. Secondly, we analysed how the various related policies resulted in the changing landscape of the bicycle mode share, including increasing in the bicycle mode share, created the conflicts and declined the bicycle mode share. The...
S. Sridhar; HARSHENDRA. N. SHET. K
2011-01-01
The running costs of the present vehicles are rising day by day hence common man is looking for an alternate mode of transport, with low fuel and maintenance cost. Solar bicycle is an attempt to meet these needs. It is an environmentally sustainable and zero running cost vehicle. It uses photovoltaic cells to absorb energy from sunlight. The absorbed energy is stored in battery. The hub motor mounted on the rear wheel uses this energy to run the cycle. A fully charged battery gives a mileage ...
Schantz Peter; Wahlgren Lina
2011-01-01
Abstract Background Route environments can positively influence people's active commuting and thereby contribute to public health. The Active Commuting Route Environment Scale (ACRES) was developed to study active commuters' perceptions of their route environments. However, bicycle commuters represent a small portion of the population in many cities and thus are difficult to study using population-based material. Therefore, the aim of this study is to expand the state of knowledge concerning ...
SRIDHAR. S
2011-07-01
Full Text Available The running costs of the present vehicles are rising day by day hence common man is looking for an alternate mode of transport, with low fuel and maintenance cost. Solar bicycle is an attempt to meet these needs. It is an environmentally sustainable and zero running cost vehicle. It uses photovoltaic cells to absorb energy from sunlight. The absorbed energy is stored in battery. The hub motor mounted on the rear wheel uses this energy to run the cycle. A fully charged battery gives a mileage of 15-20 km. It is also provided with manual pedaling which increases the cycle’s mileage further. Average speed of the cycle is 15-18 kmph.
Lina Wahlgren
2014-08-01
Full Text Available Background and Aim: Commuting by bicycle could contribute to public health, and route environments may influence this behaviour. Therefore, the aim of this study is to assess the potential associations between appraisals of the overall route environment as hindering or stimulating for bicycle commuting, with both perceptions of commuting route environmental factors in a suburban area and background factors. Methods: The Active Commuting Route Environment Scale (ACRES was used for the assessment of bicycle commuters’ perceptions and appraisals of their route environments in the suburban parts of Greater Stockholm, Sweden. A simultaneous multiple regression analysis was used to assess the relationship between the outcome variable whether the overall route environment hinders or stimulates bicycle commuting and environmental factors (e.g., exhaust fumes, speeds of motor vehicles, greenery, as well as background factors (sex, age, education, income as predictor variables. Results and Conclusions: The results indicate that in suburban areas, the factors aesthetics, greenery and bicycle paths seem to be, independently of each other, stimulating factors for bicycle commuting. On the other hand, flows of motor vehicles, noise, and low “directness” of the route seem to be hindering factors. A comparison of these results with those obtained from an inner urban area points to the importance of studying different types of built-up areas separately.
Commutative Quaternion Matrices
Kösal, Hidayet Hüda; Tosun, Murat
2013-01-01
In this study, we introduce the concept of commutative quaternions and commutative quaternion matrices. Firstly, we give some properties of commutative quaternions and their Hamilton matrices. After that we investigate commutative quaternion matrices using properties of complex matrices. Then we de?ne the complex adjoint matrix of commutative quaternion matrices and give some of their properties.
The Educational Bias in Commuting Patterns: Micro-Evidence for the Netherlands
Groot, S.P.T.; Groot, de, H.L.F.; Veneri, P.
2012-01-01
This study analyses the relation between education and commuting behaviour of Dutch workers. Results show that, ceteris paribus, higher educated workers commute further, both in terms of distance and time. In addition, higher educated workers are more frequent users of public transport and of bicycles. Furthermore, we find that higher educated workers are relatively more likely to commute towards agglomerated areas and areas that pay relatively high wages, while they are more likely to live i...
Yu, James; Arellano , Secundino; Carrillo , Alma; Cruz , Melinda; Kunitskiy, Dmitriy; Maynigo , Marlo; Sell , Monica
2013-01-01
Project Description: Bicycle detection has become a popular feature of high demand in cities and agencies across the United States. California has recently mandated that all new limit line detector installations as well as modifications to existing limit line detection must provide bicycle detection. This has created the need to develop detection methodologies which are able to detect bicycles as well as differentiate them from vehicles. The objective of this project is to utilize Econolite ...
Basso Puig, Carlos
2014-01-01
The subject of this project is the design of a recumbent bicycle prototype. A recumbent bike is a type of bicycle in which the rider mounts in a reclined position. In order to do this, we will learn about these bicycles by showing the different types there are, its evolution over the years, and so on. After that, it is shown the recumbent bicycle design and all its components. It has been invented the frame and so, it is explained the material choice, a brief anthropometric study and FE...
Giancarlo Bacchieri
2010-10-01
resultado.OBJECTIVE: To evaluate an educational intervention designed to prevent traffic accidents among workers that use the bicycle for commuting. METHODS: A longitudinal intervention study with a stepped wedge implementation was carried out between January 2006 and May 2007. Five neighborhoods with distinct geographic characteristics were selected in the city of Pelotas, Brazil, and 42 census tracts were randomly selected from these neighborhoods. All households were screened for male bicycle commuters, resulting in a sample of 1,133 individuals. The outcomes analyzed were "traffic accidents" and "near accidents". The cyclists were interviewed monthly by phone to record traffic accidents and "near accidents". Every 15 days, from the second month of study, a group of about 60 cyclists was invited to attend the intervention meeting that included an educational component (a talk and a video presentation, distribution of a safety kit (reflective belt & sash, reflective tape and an educational booklet and a bicycle breaks check-up (maintenance performed if necessary. Poisson regression adjusted for time effect was used to assess the intervention effect. RESULTS: Nearly 45% of the cyclists did not attend the intervention. During the study period, 9% of the study individuals reported a traffic accident and 88% reported a "near accident". In total there were 106 accidents and 1,091 near accidents. There was no effect observed from the intervention on either of the outcomes. CONCLUSIONS: The intervention tested was not capable of reducing traffic accidents among bicycle commuters. Lack of interest in safety by commuters and external factors, such as road design and motorist behavior, may have together influenced this result.
Simone, G. A.
1981-03-09
The objective of this Bicycle Promotion Plan is to outline a set of recommendations and supporting strategies for implementation by the US DOE toward increased use of the bicycle for energy conservation. The recommendations are designed in such a way as to function in concert with: (1) bicycle programs administered by other Federal government agencies; and (2) related programs and activities already sponsored by DOE. The approach to preparation of the Plan involved a review of all current and planned bicycle promotion programs at the Federal level as well as a review of the array of lierature on the subject. The UniWorld project staff also interacted with several DOE program offices, in order to determine the extent to which they might appropriately contribute to the implementation of bicycle promotional efforts. A synthesis of all the information gathered was published in January of 1981 as a part of the project (The Bicycle Program Review). Based upon this information and an examination of the barriers to bicycle use identified by bicycle transportation specialists in the field, UniWorld developed a series of the most potentially effective recommendations and program strategies for implementation by DOE. The recommendations address activities that could be undertaken in conjunction with existing DOE programs, new developments that might be considered to fulfill critical needs in the field, and interagency efforts that DOE could play a role in.
Van Dijk, T.
2007-01-01
For almost a century and a half, mathematicians have been racking their brains about the bike. How can a rolling bicycle be so stable of its own accord? Delft researchers now say they have completed the model to end all models. Bicycle manufacturer Batavus intends to use it to make better bikes for
National Commission on Safety Education, Washington, DC.
This material was designed to assist schools in teaching bicycle safety. As the population grows and competition for road space increases, it is more imperative than ever that we concentrate attention on the need for caution among pupil cyclists. The pamphlet: (1) discusses the role of bicycle safety in classroom instruction and in student…
Tin Tin, Sandar; Woodward, Alistair; Thornley, Simon; Langley, John; Rodgers, Anthony; Ameratunga, Shanthi
2010-03-01
Utility cycling provides substantial health, environmental and economic benefits. Despite a favourable trend in leisure-time cycling, cycling is infrequently used for everyday travel needs in New Zealand. This study investigated cyclists' attitudes toward environmental and policy measures that would encourage them to cycle more, particularly for a trip to work. A cross-sectional analysis was undertaken using baseline data obtained from the Taupo Bicycle Study, a web-based longitudinal study. The study population comprised 2469 cyclists, aged 16 years or over, who had enrolled in the 2006 Wattyl Lake Taupo Cycle Challenge. The majority (88%) reported the provision of bicycle lanes as an important factor that would encourage them to cycle more often, followed by bicycle paths (76%), better bicycle security (64%), reduced motor vehicle speed (55%) and bike friendly public transport (38%). Of those who reported travelling to work at least once a week (N = 2223), varying proportions reported shower facilities at work (61%), fewer difficult intersections (43%), rising fuel costs (41%), fewer car parks (27%), bike designed to commute (26%) and rising cost of car parking (25%) as important factors that would encourage them to cycle to work more often. There were important differences in these perceived influences defined by the participants' socio-demographic characteristics and current cycling habits. PMID:19850568
Spectra for commutative algebraists
Greenlees, J. P. C.
2006-01-01
The article is designed to explain to commutative algebraists what spectra (in the sense of algebraic topology) are, why they were originally defined, and how they can be useful for commutative algebra.
Kahle, Lynn; Eriksen, Steen Mandsfelt
2016-01-01
Morten Wagener is a Danish design, and innovator who founded the cargo and personal transportation bicycle company, ”Butchers and Bicycles,”. He identified a business opportunity to improve the future of urban transport. His idea was that most of the trikes) on the market lacked good design, maneuverability and styling. With his engineering and design background, Wagener set out to design a new trike; which would meet the needs of the target market, which his research identified as well- educ...
SHAPES: A new survey on accident risks and injuries in commuter cyclists in Belgium
de Geus, B.; Vandenbulcke, G.; Int Panis, Luc; Torfs, R; Degraeuwe, B.; I Thomas
2009-01-01
The health enhancing effects of regular bicycling (e.g. commuter cycling) are well known, however this health benefit has also a negative aspect especially when safety is neglected. Bicyclists have a higher risk of being injured than any other group of road users. They are “unprotected” in traffic, despite being capable of reaching high speeds. This increases the risk and severity of the injury. Bicycle related injury statistics from police, hospital and insurance statistics are well describe...
Transition to a cyclable city: policies and variables affecting cycling commuting
Muñoz López, Begoña; López Suárez, Elena; Monzón de Cáceres, Andrés
2014-01-01
The growing interest in achieving the objectives of cycling policies has increased the need to know the key variables that influence the use of the bicycle for daily mobility. This paper makes a contribution in this research line by examining a varying nature of variables – objective and psychological - and their influence on cycling commuting in the context of a “climber cycling city”: Vitoria-Gasteiz (Spain). Statistical differences of the variables were determined between cycling commut...
Pedersenn, Pia; Breitenstein, Marcus Lindgaard; Nilsson, Asbjørn Lupo
2014-01-01
The research area involves the cycling culture in Denmark. Cycling is one of the main forms of transport in Denmark today, and it has been a big part of Denmark’s culture since the early 20th century. This project specifically looks at bicycle helmets. Today in Denmark, there is no legislation demanding cyclists to wear helmets. However we would like to investigate what the government’s stance is concerning bicycle helmets. The project will begin by looking at the efficiency of helmets. Some ...
Commutative combinatorial Hopf algebras
Hivert, F.; Novelli, J. -C.; Thibon, J. -Y.
2006-01-01
We propose several constructions of commutative or cocommutative Hopf algebras based on various combinatorial structures, and investigate the relations between them. A commutative Hopf algebra of permutations is obtained by a general construction based on graphs, and its non-commutative dual is realized in three different ways, in particular as the Grossman-Larson algebra of heap ordered trees. Extensions to endofunctions, parking functions, set compositions, set partitions, planar binary tre...
Mulalic, Ismir; Ommeren, Jos N. van; Pilegaard, Ninette
2011-01-01
income tax reductions associated with commuting do not apply, one kilometre increase in commuting distance induces a wage increase of about 0.42%, suggesting an hourly compensation of about half of the hourly net wage. Our findings are consistent with wage bargaining theory and suggest a bargaining power...
Mulalic, Ismir; Ommeren, Jos N. van; Pilegaard, Ninette
2011-01-01
We examine the causal effect of commuting distance on workers' wages in a quasi-natural experiments setting using information on all workers in Denmark. We account for endogeneity of distance by using changes in distance that are due to firms’ relocations. For the range of commuting distances whe...
Kahle, Lynn; Eriksen, Steen Mandsfelt
2016-01-01
Morten Wagener is a Danish design, and innovator who founded the cargo and personal transportation bicycle company, ”Butchers and Bicycles,”. He identified a business opportunity to improve the future of urban transport. His idea was that most of the trikes) on the market lacked good design......, maneuverability and styling. With his engineering and design background, Wagener set out to design a new trike; which would meet the needs of the target market, which his research identified as well- educated individuals who were very interested in aesthetics. Furthermore, Wagener was convinced that trikes were...... between order and delivery. From a marketing perspective, one of the differentiating factors of Morten’s product is the quality of the ride (compared to competing products) and so his marketing team coined the slogan “Built-to-Tilt” because even though it’s a trike it feels like riding a two...
Electric power generating bicycle
Brito, Nuno; Ribeiro, Luís; Esteves, João Sena
2006-01-01
It is manifest the growing interest in both personal health and environmental issues. The device described on this paper contemplates both aspects: generating environment-friendly electric power while keeping fit. A car alternator excited through a 12V battery is coupled to a mountain bicycle, and this arrangement enables the lighting of six halogen lamps, if a cyclist pedals fast enough. Such a machine gives rise to the thought of a self-powered gymnasium. Considerable physical effort is req...
Envelopes of Commutative Rings
Rafael PARRA; Manuel SAOR(I)N
2012-01-01
Given a significative class F of commutative rings,we study the precise conditions under which a commutative ring R has an F-envelope.A full answer is obtained when.F is the class of fields,semisimple commutative rings or integral domains.When F is the class of Noetherian rings,we give a full answer when the Krull dimension of R is zero and when the envelope is required to be epimorphic.The general problem is reduced to identifying the class of non-Noetherian rings having a monomorphic Noetherian envelope,which we conjecture is the empty class.
Hazrat, R; Vavilov, N A; Zhang, Z
2011-01-01
In the present paper we discuss some recent versions of localisation methods for calculations in the groups of points of algebraic-like and classical-like groups. Namely, we describe relative localisation, universal localisation, and enhanced versions of localisation-completion. Apart from the general strategic description of these methods, we state some typical technical results of the conjugation calculus and the commutator calculus. Also, we state several recent results obtained therewith, such as relative standard commutator formulae, bounded width of commutators, with respect to the elementary generators, and nilpotent filtrations of congruence subgroups. Overall, this shows that localisation methods can be much more efficient, than expected.
Non-commutative P-1-bundles over commutative schemes
Van den Bergh, Michel
2012-01-01
In this paper we develop the theory of non-commutative P-1-bundles over commutative (smooth) schemes. Such non-commutative P-1-bundles occur in the theory of D-modules but our definition is more general. We can show that every non-commutative deformation of a Hirzebruch surface is given by a non-commutative P-1-bundle over P-1 in our sense.
The evaluation of bicycle paths on bridges
Wang, Hwa-chyi; De Backer, Hans; Lauwers, Dirk; Chang, SK Jason
2016-01-01
Bicycle accidents have increasingly caused casualties and property damage. Many countries have therefore started to pay more attention to designing the space of bicycle paths. However, few studies have focused on the design of bicycle continuity between each bicycle path. In this study, the concept of using both spatial crash probability (P) and crash severity index (CSI) is introduced to address the bicycle safety issue on bridges in Central Business Districts (CBDs). Bicycle paths on bridge...
US Agency for International Development — This dataset is the USAID portion of a larger dataset developed by OMB to better understand and to quanity the carbon footprint of the daily commute of government...
Aste, Andreas
2013-01-01
A simple exposition of the rarely discussed fact that a set of free boson fields describing different, i.e. kinematically different particle types can be quantized with mutual anticommutation relations is given by the explicit construction of the Klein transformations changing anticommutation relations into commutation relations. The analogous situation for two independent free fermion fields with mutual commutation or anticommutation relations is briefly investigated.
Commutation and Darboux transformation
M V Prabhakar; H Bhate
2015-11-01
In this paper we show that the Darboux transformation for a large class of nonlinear evolution equations arises due to factorization and commutation. The factorization and commutation has been pointed out earlier for Schrödinger operator. We show that it extends to a large class of nonlinear differential equations which admit Lax pairs including Boussinesq, Davey–Stewartson, Bogoyavlensky–Schiff and -wave interaction equation.
Sequences of commutator operations
Aichinger, Erhard
2012-01-01
Given the congruence lattice L of a finite algebra A with a Mal'cev term, we look for those sequences of operations on L that are sequences of higher commutator operations of expansions of A. The properties of higher commutators proved so far delimit the number of such sequences: the number is always at most countably infinite; if it is infinite, then L is the union of two proper subintervals with nonempty intersection.
The Bicycle Assembly Line Game
Klotz, Dorothy
2011-01-01
"The Bicycle Assembly Line Game" is a team-based, in-class activity that helps students develop a basic understanding of continuously operating processes. Each team of 7-10 students selects one of seven prefigured bicycle assembly lines to operate. The lines are run in real-time, and the team that operates the line that yields the…
Computational commutative and non-commutative algebraic geometry
Cojocaru, S; Ufnarovski, V
2005-01-01
This publication gives a good insight in the interplay between commutative and non-commutative algebraic geometry. The theoretical and computational aspects are the central theme in this study. The topic is looked at from different perspectives in over 20 lecture reports. It emphasizes the current trends in commutative and non-commutative algebraic geometry and algebra. The contributors to this publication present the most recent and state-of-the-art progresses which reflect the topic discussed in this publication. Both researchers and graduate students will find this book a good source of information on commutative and non-commutative algebraic geometry.
Bicycle Rider Control: Observations, Modeling & Experiments
Kooijman, J.D.G.
2012-01-01
Bicycle designers traditionally develop bicycles based on experience and trial and error. Adopting modern engineering tools to model bicycle and rider dynamics and control is another method for developing bicycles. This method has the potential to evaluate the complete design space, and thereby dev
Ried-Larsen, M; Grøntved, A; Østergaard, L; Cooper, A R; Froberg, K; Andersen, L B; Møller, N C
2015-10-01
The aim of the study was to investigate the associations between bicycling and carotid arterial stiffness, independent of objectively measured moderate-and-vigorous physical activity. This cross-sectional study included 375 adolescents (age 15.7 ± 0.4 years) from the Danish site of the European Youth Heart Study. Total frequency of bicycle usage was assessed by self-report, and carotid arterial stiffness was assessed using B-mode ultrasound. After adjusting for pubertal status, body height, and objectively measured physical activity and other personal lifestyle and demographic factors, boys using their bicycle every day of the week displayed a higher carotid arterial compliance {standard beta 0.47 [95% confidence interval (CI) 0.07-0.87]} and distension [standard beta 0.38 (95% CI -0.04 to 0.81)]. Boys using their bicycle every day of the week furthermore displayed a lower Young's elastic modulus [standard beta -0.48 (95% CI -0.91 to -0.06)]. Similar trends were observed when investigating the association between commuter bicycling and carotid arterial stiffness. These associations were not observed in girls. Our observations suggest that increasing bicycling in adolescence may be beneficial to carotid arterial health among boys. PMID:25156494
[Prevention of bicycle accidents].
Zwipp, H; Barthel, P; Bönninger, J; Bürkle, H; Hagemeister, C; Hannawald, L; Huhn, R; Kühn, M; Liers, H; Maier, R; Otte, D; Prokop, G; Seeck, A; Sturm, J; Unger, T
2015-04-01
For a very precise analysis of all injured bicyclists in Germany it would be important to have definitions for "severely injured", "seriously injured" and "critically injured". By this, e.g., two-thirds of surgically treated bicyclists who are not registered by the police could become available for a general analysis. Elderly bicyclists (> 60 years) are a minority (10 %) but represent a majority (50 %) of all fatalities. They profit most by wearing a helmet and would be less injured by using special bicycle bags, switching on their hearing aids and following all traffic rules. E-bikes are used more and more (145 % more in 2012 vs. 2011) with 600,000 at the end of 2011 and are increasingly involved in accidents but still have a lack of legislation. So even for pedelecs 45 with 500 W and a possible speed of 45 km/h there is still no legislative demand for the use of a protecting helmet. 96 % of all injured cyclists in Germany had more than 0.5 ‰ alcohol in their blood, 86 % more than 1.1 ‰ and 59 % more than 1.7 ‰. Fatalities are seen in 24.2 % of cases without any collision partner. Therefore the ADFC calls for a limit of 1.1 ‰. Some virtual studies conclude that integrated sensors in bicycle helmets which would interact with sensors in cars could prevent collisions or reduce the severity of injury by stopping the cars automatically. Integrated sensors in cars with opening angles of 180° enable about 93 % of all bicyclists to be detected leading to a high rate of injury avoidance and/or mitigation. Hanging lamps reduce with 35 % significantly bicycle accidents for children, traffic education for children and special trainings for elderly bicyclists are also recommended as prevention tools. As long as helmet use for bicyclists in Germany rates only 9 % on average and legislative orders for using a helmet will not be in force in the near future, coming up campaigns seem to be necessary to be promoted by the Deutscher
Cabré Viñeta, Anna
2010-01-01
The purpose of this study is to make an electrical bicycle. As this bike has an electrical motor, it will not be used as a sport method, the main idea is to use it as a public transport so people can move from side to side of the city without traffic, without pollution and without getting tired. Once selected the purpose of the bicycle, it is necessary to take into account the main features that it must have. A bicycle used as a transport around the city needs to be easy to ...
Jafari, Abolfazl
2015-01-01
We obtain generalized spatial non-commutativity consists in other than the Minkowski space time. We develop coordinates non-commutativity into more general manifolds by exploiting the translator and its manipulated form in the quantum mechanics level. Also, we employed an established local framework on a tangent space time in order to consider all of the expansions in first order of the Riemann's curvature tensor. The important point of this article is to use the homomorphism between the Minkowski and pseudo Riemann's manifolds.
Frobenius Splitting in Commutative Algebra
Smith, Karen E.; ZHANG, WENLIANG
2014-01-01
This is a survey of Frobenius splitting techniques in commutative algebra, based on the first author's lectures at the introductory workshop for the special year in commutative algebra at MSRI in fall 2012.
Hyperholomorphic functions on commutative algebras
Pogorui, Anatoliy A.
2006-01-01
In this paper we study properties of hyperholomorphic functions on commutative finite algebras. It is investigated the Cauchy-Riemann type conditions for hyperholomorphic functions. We prove that a hyperholomorphic function on a commutative finite algebra can be expanded in a Taylor series. We also present a technique for computing zeros of polynomials in some commutative algebras.
Design of Electric Bicycle Controller
Jie Cong
2009-01-01
This article introduces a sort of intelligent brushless DC motor driver and its concrete application in electric bicycle, and discusses the hardware and software design scheme of the controller, and realizes the speed control, over-current protection and battery under-voltage protection of the brushless DC motor. And the experiment result indicates that the control effect is good, and it could fulfill the application requirement of electric bicycle.
Control for an Autonomous Bicycle
Getz, Neil H.; Marsden, J. E.
1995-01-01
The control of nonholonomic and underactuated systems with symmetry is illustrated by the problem of controlling a bicycle. We derive a controller which, using steering and rear-wheel torque, causes a model of a riderless bicycle to recover its balance from a near fall as well as converge to a time parameterized path in the ground plane. Our construction utilizes new results for both the derivation of equations of motion for nonholonomic systems with symmetry, as well as the control of undera...
Workshop on Commutative Algebra
Simis, Aron
1990-01-01
The central theme of this volume is commutative algebra, with emphasis on special graded algebras, which are increasingly of interest in problems of algebraic geometry, combinatorics and computer algebra. Most of the papers have partly survey character, but are research-oriented, aiming at classification and structural results.
Ambrozie, Calin-Grigore; Müller, Vladimír
Basel: Springer, 2015 - (Alpay, D.), s. 1093-1124 ISBN 978-3-0348-0666-4 Institutional support: RVO:67985840 Keywords : commuting multioperator * dilation * von Neumann inequality Subject RIV: BA - General Mathematics http://link.springer.com/referenceworkentry/10.1007%2F978-3-0348-0667-1_58
Schantz Peter
2011-01-01
Full Text Available Abstract Background Route environments can positively influence people's active commuting and thereby contribute to public health. The Active Commuting Route Environment Scale (ACRES was developed to study active commuters' perceptions of their route environments. However, bicycle commuters represent a small portion of the population in many cities and thus are difficult to study using population-based material. Therefore, the aim of this study is to expand the state of knowledge concerning the criterion-related validity of the ACRES and the representativity using an advertisement-recruited sample. Furthermore, by comparing commuting route environment profiles of inner urban and suburban areas, we provide a novel basis for understanding the relationship between environment and bikeability. Methods Bicycle commuters from Greater Stockholm, Sweden, advertisement- (n = 1379 and street-recruited (n = 93, responded to the ACRES. Traffic planning and environmental experts from the Municipality of Stockholm (n = 24 responded to a modified version of the ACRES. The criterion-related validity assessments were based on whether or not differences between the inner urban and the suburban route environments, as indicated by the experts and by four existing objective measurements, were reflected by differences in perceptions of these environments. Comparisons of ratings between advertisement- and street-recruited participants were used for the assessments of representativity. Finally, ratings of inner urban and suburban route environments were used to evaluate commuting route environment profiles. Results Differences in ratings of the inner urban and suburban route environments by the advertisement-recruited participants were in accord with the existing objective measurements and corresponded reasonably well with those of the experts. Overall, there was a reasonably good correspondence between the advertisement- and street-recruited participants' ratings
Simulation of Population-Based Commuter Exposure to NO2 Using Different Air Pollution Models
Martina S. Ragettli
2014-05-01
Full Text Available We simulated commuter routes and long-term exposure to traffic-related air pollution during commute in a representative population sample in Basel (Switzerland, and evaluated three air pollution models with different spatial resolution for estimating commute exposures to nitrogen dioxide (NO2 as a marker of long-term exposure to traffic-related air pollution. Our approach includes spatially and temporally resolved data on actual commuter routes, travel modes and three air pollution models. Annual mean NO2 commuter exposures were similar between models. However, we found more within-city and within-subject variability in annual mean (±SD NO2 commuter exposure with a high resolution dispersion model (40 ± 7 µg m−3, range: 21–61 than with a dispersion model with a lower resolution (39 ± 5 µg m−3; range: 24–51, and a land use regression model (41 ± 5 µg m−3; range: 24–54. Highest median cumulative exposures were calculated along motorized transport and bicycle routes, and the lowest for walking. For estimating commuter exposure within a city and being interested also in small-scale variability between roads, a model with a high resolution is recommended. For larger scale epidemiological health assessment studies, models with a coarser spatial resolution are likely sufficient, especially when study areas include suburban and rural areas.
Employee commute options guidance
The Clean Air Act Amendments of 1990 (CAAA) require severe and extreme ozone nonattainment areas and serious carbon monoxide nonattainment areas to establish programs aimed at reducing commute trips to the worksites of large employers. The concerns that lead to the inclusion of the Employee Commute Options (ECO) provision in the Act are that more people are driving than ever before and they are driving longer distances. The purpose of the guidance is to inform the affected State and local jurisdictions of the Clean Air Act requirement, to provide guidance on preparing an approvable State Implementation Plan (SIP) revision, and to discuss various approaches which may help areas achieve Clean Air Act targets through implementation strategies that are the least burdensome and costly to both affected employers and employees
Hazrat, R.; Zhang, Z.
2011-01-01
Let A be a quasi-finite R-algebra (i.e., a direct limit of module finite algebras) with identity. Let I_i, i=0,...,m, be two-sided ideals of A, \\GL_n(A,I_i) the principal congruence subgroup of level I_i in GL_n(A) and E_n(A,I_i) be the relative elementary subgroup of level I_i. We prove a multiple commutator formula [E_n(A,I_0),\\GL_n(A,I_1),& \\GL_n(A, I_2),..., \\GL_n(A, I_m)] = [E_n(A,I_0),E_n(A,I_1),E_n(A, I_2),..., E_n(A, I_m)], which is a broad generalization of the standard commutator fo...
Probing deformed quantum commutators
Rossi, Matteo A. C.; Giani, Tommaso; Paris, Matteo G. A.
2016-07-01
Several quantum gravity theories predict a minimal length at the order of magnitude of the Planck length, under which the concepts of space and time lose their physical meaning. In quantum mechanics, the insurgence of such a minimal length can be described by introducing a modified position-momentum commutator, which in turn yields a generalized uncertainty principle, where the uncertainty on position measurements has a lower bound. The value of the minimal length is not predicted by theories and must be estimated experimentally. In this paper, we address the quantum bound to the estimability of the minimal uncertainty length by performing measurements on a harmonic oscillator, which is analytically solvable in the deformed algebra induced by the deformed commutation relations.
Hazrat, R.; Stepanov, A. V.; Vavilov, N. A.; Zhang, Z.
2011-01-01
In the present paper we discuss some recent versions of localisation methods for calculations in the groups of points of algebraic-like and classical-like groups. Namely, we describe relative localisation, universal localisation, and enhanced versions of localisation-completion. Apart from the general strategic description of these methods, we state some typical technical results of the conjugation calculus and the commutator calculus. Also, we state several recent results obtained therewith,...
Wahlgren Lina
2012-03-01
Full Text Available Abstract Background Route environments may influence people's active commuting positively and thereby contribute to public health. Assessments of route environments are, however, needed in order to better understand the possible relationship between active commuting and the route environment. The aim of this study was, therefore, to assess the potential associations between perceptions of whether the route environment on the whole hinders or stimulates bicycle commuting and perceptions of environmental factors. Methods The Active Commuting Route Environment Scale (ACRES was used for the assessment of bicycle commuters' perceptions of their route environments in the inner urban parts of Greater Stockholm, Sweden. Bicycle commuters (n = 827 were recruited by advertisements in newspapers. Simultaneous multiple regression analyses were used to assess the relation between predictor variables (such as levels of exhaust fumes, noise, traffic speed, traffic congestion and greenery and the outcome variable (hindering - stimulating route environments. Two models were run, (Model 1 without and (Model 2 with the item traffic: unsafe or safe included as a predictor. Results Overall, about 40% of the variance of hindering - stimulating route environments was explained by the environmental predictors in our models (Model 1, R2 = 0.415, and Model 2, R 2= 0.435. The regression equation for Model 1 was: y = 8.53 + 0.33 ugly or beautiful + 0.14 greenery + (-0.14 course of the route + (-0.13 exhaust fumes + (-0.09 congestion: all types of vehicles (p ≤ 0.019. The regression equation for Model 2 was y = 6.55 + 0.31 ugly or beautiful + 0.16 traffic: unsafe or safe + (-0.13 exhaust fumes + 0.12 greenery + (-0.12 course of the route (p ≤ 0.001. Conclusions The main results indicate that beautiful, green and safe route environments seem to be, independently of each other, stimulating factors for bicycle commuting in inner urban areas. On the other hand, exhaust
Valuing public investments to support bicycling
Götschi, Thomas; Hintermann, Beat
2014-01-01
We develop a framework for assessing the net benefits of investments to promote bicycling, which explicitly accounts for internal costs of bicycling. We apply our model to eight Swiss cities using data from the Swiss national travel survey and find that increasing the level of bicycling by reducing internal costs leads to inframarginal benefits that exceed the net benefits from the additional bicycling. We further find that Swiss cyclists only partially internalize health benefits, which aff...
2010-10-01
... 45 Public Welfare 1 2010-10-01 2010-10-01 false Bicycles. 3.27 Section 3.27 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION CONDUCT OF PERSONS AND TRAFFIC ON THE NATIONAL INSTITUTES OF HEALTH FEDERAL ENCLAVE Traffic Regulations § 3.27 Bicycles. A person may not operate a bicycle, motorbike, or similar vehicle...
2010-07-01
... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Bicycles. 13.1324 Section 13.1324 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL... (egda) § 13.1324 Bicycles. Within the EGDA, the use of a bicycle is prohibited except on the...
2010-07-01
... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Bicycles. 13.1126 Section 13.1126 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL... § 13.1126 Bicycles. Use of a bicycle is prohibited on the Forest Loop, Bartlett River and Bartlett...
Radar channel balancing with commutation
Doerry, Armin Walter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2014-02-01
When multiple channels are employed in a pulse-Doppler radar, achieving and maintaining balance between the channels is problematic. In some circumstances the channels may be commutated to achieve adequate balance. Commutation is the switching, trading, toggling, or multiplexing of the channels between signal paths. Commutation allows modulating the imbalance energy away from the balanced energy in Doppler, where it can be mitigated with filtering.
EP BICYCLE POOL - VIGNETTES 2002
EP-SMI Help Desk
2002-01-01
The vignettes (insurance certificates) for 2002 become obligatory from 1 June. If you have a bicycle from the EP Pool, please bring it to the EP-SMI Help Desk (Building 124) on any working day up to 31 May between 8h.30 - 12h.00 or 13h.30 - 17h.30. EP-SMI Help Desk
Challenges in Computational Commutative Algebra
Abbott, John
2006-01-01
In this paper we consider a number of challenges from the point of view of the CoCoA project one of whose tasks is to develop software specialized for computations in commutative algebra. Some of the challenges extend considerably beyond the boundary of commutative algebra, and are addressed to the computer algebra community as a whole.
George Hess
Full Text Available Many global challenges, including obesity, health care costs, and climate change, could be addressed in part by increasing the use of bicycles for transportation. Concern about the safety of bicycling on roadways is frequently cited as a deterrent to increasing bicycle use in the USA. The use of effective signage along roadways might help alleviate these concerns by increasing knowledge about the rights and duties of bicyclists and motorists, ideally reducing crashes. We administered a web-based survey, using Twitter for recruitment, to examine how well three US traffic control devices communicated the message that bicyclists are permitted in the center of the travel lane and do not have to "get out of the way" to allow motorists to pass without changing lanes: "Bicycles May Use Full Lane" and "Share the Road" signage, and Shared Lane Markings on the pavement. Each was compared to an unsigned roadway. We also asked respondents whether it was safe for a bicyclist to occupy the center of the travel lane. "Bicycles May Use Full Lane" signage was the most consistently comprehended device for communicating the message that bicyclists may occupy the travel lane and also increased perceptions of safety. "Share the Road" signage did not increase comprehension or perceptions of safety. Shared Lane Markings fell somewhere between. "Bicycles May Use Full Lane" signage showed notable increases in comprehension among novice bicyclists and private motor vehicle commuters, critical target audiences for efforts to promote bicycling in the USA. Although limited in scope, our survey results are indicative and suggest that Departments of Transportation consider replacing "Share the Road" with "Bicycles May Use Full Lane" signage, possibly combined with Shared Lane Markings, if the intent is to increase awareness of roadway rights and responsibilities. Further evaluation through virtual reality simulations and on-road experiments is merited.
Combinatorics and commutative algebra
Stanley, Richard P
1996-01-01
Some remarkable connections between commutative algebra and combinatorics have been discovered in recent years. This book provides an overview of two of the main topics in this area. The first concerns the solutions of linear equations in nonnegative integers. Applications are given to the enumeration of integer stochastic matrices (or magic squares), the volume of polytopes, combinatorial reciprocity theorems, and related results. The second topic deals with the face ring of a simplicial complex, and includes a proof of the Upper Bound Conjecture for Spheres. An introductory chapter giving background information in algebra, combinatorics and topology broadens access to this material for non-specialists. New to this edition is a chapter surveying more recent work related to face rings, focusing on applications to f-vectors. Included in this chapter is an outline of the proof of McMullen's g-conjecture for simplicial polytopes based on toric varieties, as well as a discussion of the face rings of such special ...
Rossi, Matteo A C; Paris, Matteo G A
2016-01-01
Quantum gravity theories predict a minimal length at the order of magnitude of the Planck length, under which the concepts of space and time lose every physical meaning. In quantum mechanics, the insurgence of such minimal length can be described by introducing a modified position-momentum commutator, which in turn yields a generalized uncertainty principle, where the uncertainty on the position measurement has a lower bound. The value of the minimal length is not predicted by theories and must be evaluated experimentally. In this paper, we address the quantum bound to estimability of the minimal uncertainty length by performing measurements on a harmonic oscillator, which is analytically solvable in the deformed algebra of the Hilbert subspace.
Macroscopic modeling of pedestrian and bicycle crashes: A cross-comparison of estimation methods.
Amoh-Gyimah, Richard; Saberi, Meead; Sarvi, Majid
2016-08-01
The paper presents a cross-comparison of different estimation methods to model pedestrian and bicycle crashes. The study contributes to macro level safety studies by providing further methodological and empirical evidence on the various factors that influence the frequency of pedestrian and bicycle crashes at the planning level. Random parameter negative binomial (RPNB) models are estimated to explore the effects of various planning factors associated with total, serious injury and minor injury crashes while accounting for unobserved heterogeneity. Results of the RPNB models were compared with the results of a non-spatial negative binomial (NB) model and a Poisson-Gamma-CAR model. Key findings are, (1) the RPNB model performed best with the lowest mean absolute deviation, mean squared predicted error and Akaiki information criterion measures and (2) signs of estimated parameters are consistent if these variables are significant in models with the same response variables. We found that vehicle kilometers traveled (VKT), population, percentage of commuters cycling or walking to work, and percentage of households without motor vehicles have a significant and positive correlation with the number of pedestrian and bicycle crashes. Mixed land use is also found to have a positive association with the number of pedestrian and bicycle crashes. Results have planning and policy implications aimed at encouraging the use of sustainable modes of transportation while ensuring the safety of pedestrians and cyclist. PMID:27209153
Characterisation of Electric Bicycles Performances
Cappelle, Jan; Lataire, Philippe; Maggetto, Gaston; Meeusen, Roman; Kempenaers, Farid
2002-01-01
The proposed paper reports on characterisation work performed in the scope of the E-tour project. This project has already been presented at EVS-18. At the ‘Vrije Universiteit Brussel’ different EPACs (Electric Power Assisted Cycles) are put at the public’s disposal for testing. To quantify the performances of these electrical bicycles we want to link the subjective experienced driving comfort to some measurable objective parameters. For this purpose we converted a treadmill in...
Topics in commutative ring theory
Watkins, John J
2009-01-01
Topics in Commutative Ring Theory is a textbook for advanced undergraduate students as well as graduate students and mathematicians seeking an accessible introduction to this fascinating area of abstract algebra. Commutative ring theory arose more than a century ago to address questions in geometry and number theory. A commutative ring is a set-such as the integers, complex numbers, or polynomials with real coefficients--with two operations, addition and multiplication. Starting from this simple definition, John Watkins guides readers from basic concepts to Noetherian rings-one of
Commutative and Non-commutative Parallelogram Geometry: an Experimental Approach
Bertram, Wolfgang
2013-01-01
By "parallelogram geometry" we mean the elementary, "commutative", geometry corresponding to vector addition, and by "trapezoid geometry" a certain "non-commutative deformation" of the former. This text presents an elementary approach via exercises using dynamical software (such as geogebra), hopefully accessible to a wide mathematical audience, from undergraduate students and high school teachers to researchers, proceeding in three steps: (1) experimental geometry, (2) algebra (linear algebr...
Commutative and Non-commutative Parallelogram Geometry: en Experimental Approach
Bertram, Wolfgang
2013-01-01
By ''parallelogram geometry'' we mean the elementary, ''commutative'', geometry corresponding to vector addition, and by ''trapezoid geometry'' a certain ''non-commutative deformation'' of the former. This text presents an elementary approach via exercises using dynamical software (such as geogebra), hopefully accessible to a wide mathematical audience, from undergraduate students and high school teachers to researchers, proceeding in three steps: (1) experimental geometry, (2) algebra (linea...
Approximate double commutants in von Neumann algebras
Hadwin, Don
2011-01-01
Richard Kadison showed that not every commutative von Neumann subalgebra of a factor von Neumann algebra is equal to its relative double commutant. We prove that every commutative C*-subalgebra of a centrally prime C*-algebra $B$ equals its relative approximate double commutant. If $B$ is a von Neumann algebra, there is a related distance formula.
Intelligent Power Assist Algorithms for Electric Bicycles
Fan, Xuan
2010-01-01
This dissertation considers intelligent power-assist algorithm designs for electric bicycles. Traditional electric power-assist bicycles (EPBs) employ proportional power-assist strategy. The ratio is usually set to 1:1, which means that the motor will provide the same amount of assistive torque as the amount of the human's pedaling torque. This strategy is too rigid and does not consider the interaction between the bicycle, the human and the environment. Intelligent power-assist algorithms ar...
Bicycle lessons, activity participation and empowerment
Kloof, A. van der; Bastiaanssen, K.; Martens, C.J.C.M.
2014-01-01
This paper addresses the impact of bicycle lessons for immigrant and refugee women on bicycle use and activity participation. Especially non-Western immigrant and refugee women have been identified as one of the population groups most likely to experience accessibility problems and, subsequently, transport-related social exclusion. The bicycle offers considerable potential to increase the mobility of these women. Hence, in the Netherlands and elsewhere, governments and non-governmental organi...
Autonomous Bicycle: The First Self Balanced Ride
Ånnestad, Dag Christian
2011-01-01
The idea of an autonomous bicycle originates from Jens G. Balchen who wanted to make an unmanned autonomous bicycle. The idea was picked up by Amund Skavhaug who extended the idea with the concept of using an inverted pendulum to simulate a leaning rider. The previous attempts to develop a bicycle capable of performing an autonomous ride has so far all ended in failure. The main reason for the Department of Engineering Cybernetics is to develop such a bicycle is for use in recruitment and mot...
Opechowski's theorem and commutator groups
It is shown that the conditions of application of Opechowski's theorem for double groups of subgroups of O(3) are directly associated to the structure of their commutator groups. Some characteristics of the structure of classes are also discussed. (Author)
Vlist, van der, Kevin; Rouwendal, J.
2002-01-01
This paper studies the interaction between commuting, job mobility, and housing mobility. Many conventional models assume that the employment location has priority over the residential location and that the latter is adapted to the former. This implies that commutes which start with a job change will often be short lived because of a change in residential location that soon follows. It is also often supposed that the change in residential location is made with the intention to avoid long comm...
Bernardoni, S.; Iseli, A.; Munafo, S.
2009-12-15
The municipal, regional and national authorities wanted to assess the potential of electric-assisted bicycles in the Geneva region. A survey performed by the University of Geneva is reported. The following points were investigated: (i) Who uses an electric bicycle? (ii) How is an electric bicycle used? (iii) Why is an electric bicycle purchased? (iv) How many people could potentially use an electric bicycle in the Geneva region? (v) How much energy would be saved and what fraction of the carbon dioxide emissions would be avoided thanks to electric bicycles in the region? Some interesting results: Most current electric bicycle users are women and live in Geneva outskirts. Most users have an academic degree or equivalent and have a good job. Most of them have also a car and other bicycles without electric motor. The main uses of electric bicycles is commuting between house and job locations, leisure activities and shopping. The average annual distance per electric bicycle is about 3000 km. The majority of the electric bicycles in use are limited to 25 km/h and can be driven without any license. The users wish an extension of the bicycle track network along the roads and of the protected parking areas. The number of potential users in the City of Geneva is estimated to 9% or 15,600 new users and to 10% or 43,000 new users in the suburbs. In 2030, 7,500,000 litres-equivalent of gasoline could be annually saved in the region and more than 16,000 tons CO{sub 2} emissions avoided.
2010-07-01
... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Bicycle use. 13.914 Section 13.914 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL... in public parking areas, or on trails and areas designated for bicycle use by the Superintendent....
A study on electric bicycle energy efficiency
Ivan EVTIMOV
2015-09-01
Full Text Available The paper presents a construction of an experimental electric bicycle for evaluation of the energy efficiency. The bicycle is equipped with onboard computer which can store the information about motion and energy consumption. The result concerning power, energy consumption, recharging during brake process, etc. are given. Energy consumption for 3 typical city routes is studied.
Bicycle parking preferences: costs versus walking time
Molin, E.J.E.; Maat, K.
2014-01-01
Successful bicycle stimulating policies may increase the need for bicycle parking capacity, especially at main railway stations located in city centers. A potential solution for this problem involves combining paid surveyed indoor parking near the platforms and free open-air parking without surveill
Bicycle helmet use and bicycling-related injury among young Canadians: an equity analysis
2013-01-01
Introduction Cycling is a major activity for adolescents in Canada and potential differences exist in bicycling-related risk and experience of injury by population subgroup. The overall aim of this study was to inform health equity interventions by profiling stratified analytic methods and identifying potential inequities associated with bicycle-related injury and the use of bicycle helmets among Canadian youth. The two objectives of this study were: (1) To examine national patterns in bicycle ridership and also bicycle helmet use among Canadian youth in a stratified analysis by potentially vulnerable population subgroups, and (2) To examine bicycling-related injury in the same population subgroups of Canadian youth in order to identify possible health inequities. Methods Data for this study were obtained from the 6th cycle (2009/10) of the Health Behaviour in School-aged Children (HBSC) study, which is a general health survey that was completed by 26,078 students in grades 6–10 from 436 Canadian schools. Based on survey responses, we determined point prevalence for bicycle ridership, bicycle helmet use and relative risks for bicycling-related injury. Results Three quarters of all respondents were bicycle riders (n=19,410). Independent factors associated with bicycle ridership among students include being male, being a younger student, being more affluent, and being a resident of a small town. Among bicycle riders, 43% (95%CI ± 0.6%) reported never wearing and 32% (± 0.6%) inconsistently wearing a helmet. Only 26% (± 0.5%) of students reported always wearing a bicycle helmet. Helmets were less frequently used among older students and there were also important patterns by sex, geographic location and socioeconomic status. Adjusting for all other demographic characteristics, boys reported 2.02-fold increase (95% CI: 1.61 to 1.90) and new immigrants a 1.35-fold increase (95%CI: 1.00 to1.82) in the relative risk of bicycling-related injury in the past 12 months
Beijing Bicycle - Stories from a Transformative Space
Bagger-Petersen, Mai Corlin
2012-01-01
production of space that reveals how transnational and translocal mechanisms affect the cinematic language, transforming the images and stories chosen for the cinematic representation. Wang Xiaoshuai’s Beijing Bicycle (Shiqi Sui de Danche) (2001) is a result of transnational currents weaving the carpet of...... the global. Beijing Bicycle is thematically similar to Vittorio de Sicas neorealist classic Bicycle Thieves (1948) and Akira Kurosawas filmnoir classic Stray Dog (1949). Both films describe a disillusioned post-war society in an impoverished Italy and a humiliated Japan respectively. The stories told...... Xiaoshuai’s Beijing Bicycle can be understood as the result of stories-so-far, as the cinematic representation of the globalized ”space” within the setting of the national. Beijing Bicycle is a production of space as well as a space of production, since it tells a new story in the trajectory of stories...
STRESS ANALYSIS OF BICYCLE FRAME
Mr.M.V.Pazare
2014-06-01
Full Text Available This paper deals with the stress analysis of bicycle frame by using Finite Element Method. The analysis is carried out in Ansys, The F.E.A. results are compared with theoretical results. In theoretical analysis the frame is treated as truss like structure and the stresses in various members of frame like top tube, down tube, seat tube, chain stay and seat stay are determined, considering various condition like, static start up, steady state paddling, vertical impact, horizontal impact, rear wheel braking. Also Finite Element Analysis is done considering the above conditions. From the analysis it is found that there is a good agreement between analytical and F.E.A. results. Result of all the cases reveals that maximum stress is found in top tube of the bicycle frame as compared to other frame members and is equal to 24.84 MPa which is less than yield strength in tension (i.e.Syt = 290 MPa for the material (aluminum T 6061 selected.
Toshihiro Osaragi
2015-07-01
Full Text Available In the aftermath of a devastating earthquake, public transportation is presumed paralyzed and thus unavailable; large numbers of people are expected to experience difficulty in commuting. In recent years, implementation of district continuity plans (DCPs and business continuity plans (BCPs has become a major concern for local governments and private firms, respectively. In this paper, we propose a pair of simulation models seeking to examine business commutation networks in terms of their possible obstruction and eventual restoration. The first of these model commuting intentions by analyzing individual daily commutes. The second offers a mobility model of commuters’ physical endurance for travel alternatives on foot or by bicycle. Next, we proceed to gauge the number of commuters likely to experience difficulty and adjudge their spatial distribution while taking into account such attributes as gender and employment. Lastly, we attempt to assess rates and patterns in the reduction of commutation constraints based on simulations that assume a restoration of rail infrastructure or its equivalent.
Johnson Space Center's Free Range Bicycle Program.- Fall 2015 Intern Report
Lee-Stockton, Willem
2015-01-01
NASA's Johnson Space Center is a big place, encompassing 1,620 acres and more than a hundred buildings. Furthermore, there are reportedly 15 thousand employees, all of which have somewhere to be. To facilitate the movement of all these people JSC has historically relied on human power. Pedaling their way towards deep space, bicycles have been the go to method. Currently there are about 200 Free Range Bicycles at JSC. Free Range Bicycles belong to nobody, except NASA, and are available for anybody to use. They are not to be locked or hidden (although frequently are) and the intention is that there will always be a bike to hop on to get where you're going (although it may not be the bike you rode in on). Although not without its own shortcomings, the Free Range Bicycle Program has continued to provide low cost, simple transportation for NASA's JSC. In addition to the approximately 200 Free Range Bicycles, various larger divisions (like engineering) will often buy a few dozen bikes for their team members to use or individuals will bring their own personal bike to either commute or use on site. When these bicycles fall into disrepair or are abandoned (from retirees etc) they become a problem at JSC. They are an eye sore, create a safety hazard and make it harder to find a working bike in a time of need. The Free Range Program hopes to address this first problem by "tagging out" abandoned or out of service bicycles. A bright orange "DO NOT OPERATE" tag is placed on the bike and given a serial number for tracking purposes. See picture to the right. If the bike has an active owner with intentions to repair the bike the bottom of the tag has instructions for how to claim the abandoned bicycle. After being tagged the owner of the bicycle has 30 days to claim the bicycle and either haul it off site or get it repaired (and labeled) in accordance with Johnson's Bicycle Policy. If the abandoned bicycle is not claimed within 30 days it becomes the property of the Government. The
P-commutative topological *-algebras
If P(A) denotes the set of all continuous positive functionals on a unital complete Imc *-algebra and S(A) the extreme points of P(A), and if the spectrum of an element χ Ε A coincides with the set {f(χ): f Ε S(A)}, then A is shown to be P-commutative. Moreover, if A is unital symmetric Frechet Q Imc *-algebra, then this spectral condition is, in fact, necessary. Also, an isomorphism theorem between symmetric Frechet P-commutative Imc *-algebras is established. (author). 12 refs
On CNC Commuting Contractive Tuples
T Bhattacharyya; J Eschmeier; J Sarkar
2006-08-01
The characteristic function has been an important tool for studying completely non-unitary contractions on Hilbert spaces. In this note, we consider completely non-coisometric contractive tuples of commuting operators on a Hilbert space $\\mathcal{H}$. We show that the characteristic function, which is now an operator-valued analytic function on the open Euclidean unit ball in $\\mathbb{C}^n$, is a complete unitary invariant for such a tuple. We prove that the characteristic function satisfies a natural transformation law under biholomorphic mappings of the unit ball. We also characterize all operator-valued analytic functions which arise as characteristic functions of pure commuting contractive tuples.
Duality for commutative group stacks
Brochard, Sylvain
2014-01-01
We study in this article the dual of a (strictly) commutative group stack $G$ and give some applications. Using the Picard functor and the Picard stack of $G$, we first give some sufficient conditions for $G$ to be dualizable. Then, for an algebraic stack $X$ with suitable assumptions, we define an Albanese morphism $a_X : X\\to A^1(X)$ where $A^1(X)$ is a torsor under the dual commutative group stack $A^0(X)$ of $Pic_{X/S}$. We prove that $a_X$ satisfies a natural universal property. We give ...
Differential operators on non-commutative algebras
Hazewinkel, Michiel
2013-01-01
There is a relatively well-known description of the algebra of (higher order) left differential operators on commutative algebras. This note gives a construction of similar flavor for algebras of differential operators on not necessarily commutative algebras.
Commutative subalgebras of the Grassmann algebra
Domokos, M.; Zubor, M.
2014-01-01
The maximal dimension of a commutative subalgebra of the Grassmann algebra is determined. It is shown that for any commutative subalgebra there exists a commutative subalgebra which is spanned by monomials and has the same dimension. It follows that the maximal dimension of a commutative subalgebra can be expressed in terms of the maximal size of an intersecting system of subsets of odd size in a finite set.
Survey of options on legalizing bicycling (VB)
Zwahlen, Jurg; Sulewski, Sharon; Sacovitch, Stephen;
1999-01-01
opposition against the proposal was.The goal of this project was to identify categories of users that were opposed to bicycling on the Dosseringen of the Østerbro and Nørrebro District lakes in Copenhagen. The identification of the opposition and its strength, rationale and organization was in terms of age......, gender, residency, frequency of use and their utilization of the area (i.e. walking, jogging, bicycling) as compared to the support for bicycling in the area. This was an Interactive Qualifying Project (IQP), that was designed to merge technical and scientific knowledge with society, and stresses the...
Non-commutative and commutative vacua effects in a scalar torsion scenario
Haidar Sheikhahmadi
2015-10-01
Full Text Available In this work, the effects of non-commutative and commutative vacua on the phase space generated by a scalar field in a scalar torsion scenario are investigated. For both classical and quantum regimes, the commutative and non-commutative cases are compared. To take account the effects of non-commutativity, two well known non-commutative parameters, θ and β, are introduced. It should be emphasized, the effects of β which is related to momentum sector has more key role in comparison to θ which is related to space sector. Also the different boundary conditions and mathematical interpretations of non-commutativity are explored.
Segal algebras in commutative Banach algebras
INOUE, Jyunji; TAKAHASI, Sin-Ei
2014-01-01
The notion of Reiter's Segal algebra in commutative group algebras is generalized to a notion of Segal algebra in more general classes of commutative Banach algebras. Then we introduce a family of Segal algebras in commutative Banach algebras under considerations and study some properties of them.
8 CFR 211.5 - Alien commuters.
2010-01-01
... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Alien commuters. 211.5 Section 211.5 Aliens...: IMMIGRANTS; WAIVERS § 211.5 Alien commuters. (a) General. An alien lawfully admitted for permanent residence.... An alien commuter engaged in seasonal work will be presumed to have taken up residence in the...
A study of commuter airline economics
Summerfield, J. R.
1976-01-01
Variables are defined and cost relationships developed that describe the direct and indirect operating costs of commuter airlines. The study focused on costs for new aircraft and new aircraft technology when applied to the commuter airline industry. With proper judgement and selection of input variables, the operating costs model was shown to be capable of providing economic insight into other commuter airline system evaluations.
Database improvements for motor vehicle/bicycle crash analysis
Lusk, Anne C; Asgarzadeh, Morteza; Farvid, Maryam S
2015-01-01
Background: Bicycling is healthy but needs to be safer for more to bike. Police crash templates are designed for reporting crashes between motor vehicles, but not between vehicles/bicycles. If written/drawn bicycle-crash-scene details exist, these are not entered into spreadsheets. Objective: To assess which bicycle-crash-scene data might be added to spreadsheets for analysis. Methods: Police crash templates from 50 states were analysed. Reports for 3350 motor vehicle/bicycle crashes (2011) w...
Siroos Ahmadi
2013-07-01
The main goal of this research is to investigate relationship between attitude toward bicycle and using bicycle among the men in Isfahan. Based on the descriptive research findings, mean using bicycle score is low in Iran. This situation is not satisfactory for a metropolis such as Isfahan that has an increasing population and motor vehicles, and also has many difficulties in urban base facilities and must be changed. In addition to mean attitude toward bicycle is high that is an opportunity for urban planners. Inferential findings show that attitude toward bicycle has a significant impact on using bicycle. In other words, increase attitude toward bicycle means an increase in using bicycle for short trips. This research finding theoretically confirm relation between attitude and behavior. Moreover it is compatible with results of the research that show there is significant relationship between attitude toward bicycle and using bicycle. There is an inverse significant relationship between age and using bicycle and with rising age using bicycle is decreased. This research finding shows that urban infrastructure in Isfahan for using bicycle is not available and consequently with rising age, bicycle risk is increased. There is a direct significant relationship between income rate and using bicycle and with increasing income rate, using bicycle is also increased. This research finding is rooted in social prestige bicycle and higher classes prefer to use motor vehicle for transportation instead of bicycle. There is a significant relationship between marital status and using bicycle and single men use bicycle more than married men but there is no significant relationship between education level and using bicycle. This research findings show that with rising education level in spite of rising income, using bicycle is not decreased. And finally there is no significant relationship between employed and unemployed persons in using bicycle. On the basis of the evidences such
Pedaling into high gear for bicycle policy in Canada : lessons from bike summit 2008 in Toronto
The 2008 bike summit provided a forum for the discussion of international and Canadian best practices related to bicycles and bicycling policy. The aim of the summit was to assist communities across Canada to improve conditions for cycling in the urban environment and help to generate a cultural shift towards greater acceptance of cycling on roads. This paper discussed lessons learned during the summit and outlined new methods of improving cycling in communities. The City of London has recently increased the amount of cyclists using its roads by 200 per cent. Cycling infrastructure is more affordable than constructing major public transit or road infrastructure. Savings in healthcare costs will be accrued over time as a result of the healthier lifestyles promoted by regular cycling activity. Bicycle trips can help to alleviate over-demand on heavy transit routes. Encouraging commuters to cycle will also reduce the amounts of greenhouse gases (GHGs) emitted in urban areas. Lane width reductions will help to reduce speeds as drivers are forced to pay more attention when driving. Public bike sharing programs and bike stations are now being used in many North American cities. It was concluded that strong advocacy is needed to ensure the growth and acceptance of cycling in urban centres. 23 figs
Workers' marginal costs of commuting
van Ommeren, Jos; Fosgerau, Mogens
2009-01-01
This paper applies a dynamic search model to estimate workers' marginal costs of commuting, including monetary and time costs. Using data on workers' job search activity as well as moving behaviour, for the Netherlands, we provide evidence that, on average, workers' marginal costs of one hour of...
2010-07-01
... routes designated for bicycle use; provided, however, that the Board may close any Presidio Trust road or... consistent with the protection of natural, scenic and aesthetic values, safety considerations and...
2010-07-01
... road or parking area to bicycle use pursuant to the criteria and procedures of §§ 1.5 and 1.7 of this... consistent with the protection of a park area's natural, scenic and aesthetic values, safety...
Non-Commutative Q-Binomial Formula
Nalci, Sengul; Pashaev, Oktay
2012-01-01
In this paper, we found new q-binomial formula for Q-commutative operators. Expansion coefficients in this formula are given by q-binomial coefficients with two bases (q,Q), determined by Q-commutative q-Pascal triangle. Our formula generalizes all well-known binomial formulas in the form of Newton, Gauss, symmetrical, non-commutative and Binet-Fibonacci binomials. By our non-commutative q-binomial, we introduce q-analogue of function of two non-commutative variables, which could be used in s...
Design of Controller in Electric Bicycle
Zhidong Zhang; Jingfeng Shen; Baohui Li
2011-01-01
Base on PIC16F72, a design of brushless DC motor controller strategy applied to the electric bicycle control system was presented in the paper. Through analyzed some possible problems when electric bicycle running daily. Function of over-current protection, under-voltage protection and helping were accomplished. Schematic diagrams of each function and drive circuit were given in the paper, the controller was debugged in rated voltage 36V and power rating 250W brushless DC motor, experiment tu...
Profiling bicycle tourists: a case of Croatia
Kovačić, Nataša
2015-01-01
Purpose – The purpose of the primary research is to gather information about the behaviour of bicycle tourism demand. Primarily by studying domestic bicycle tourists, the research results were expected to provide valuable market parameters, comparable with the determinants of previous relevant studies. Design and Methodology – Research was carried out by surveying different segments of bicyclists, recognized in earlier conceptual contributions. Electronic data collection techniques were ap...
A note on maximal commutators and commutators of maximal functions
Mujdat, A.; Gogatishvili, Amiran; Koca, K.; Mustafayev, R.
2015-01-01
Roč. 67, č. 2 (2015), s. 581-593. ISSN 0025-5645 R&D Projects: GA ČR GA13-14743S; GA ČR GA201/08/0383 Institutional support: RVO:67985840 Keywords : macimal operator * commutator * BMO Subject RIV: BA - General Mathematics Impact factor: 0.615, year: 2014 http://projecteuclid.org/euclid.jmsj/1429624595
Is the three-foot bicycle passing law working in Baltimore, Maryland?
Love, David C; Breaud, Autumn; Burns, Sean; Margulies, Jared; Romano, Max; Lawrence, Robert
2012-09-01
Maryland (MD) recently became one of fourteen states in the United States to enact a traffic law requiring motor vehicles to pass bicyclists at a distance of greater than three feet. To our knowledge, motorist compliance with the law has never been assessed. This study measured the distance between overtaking motor vehicles and cyclists [e.g. vehicle passing distance (VPD)], to develop baseline metrics for tracking implementation of the three-foot passing law in Baltimore, MD and to assess risk factors for dangerous passes. During September and October 2011, cyclists (n=5) measured VPD using a previously published video technique (Parkin and Meyers, 2010). Cyclists logged a total of 10.8h of video footage and 586 vehicle passes on 34 bicycle commuting trips. The average trip lasted 19.5±4.9 min and cyclists were passed on average 17.2±11.8 times per trip. VPDs of three feet or less were common when cycling in standard lanes (17%; 78 of 451 passes) and lanes with a shared lane marking (e.g. sharrows) (23%; 11 of 47 passes). No passes of three feet or less occurred in bicycle lanes (0 of 88 passes). A multiple linear regression model was created, which explained 26% of the variability in VPD. Significant model variables were lane width, bicycle infrastructure, cyclist identity, and street identity. Interventions, such as driver education, signage, enforcement, and bicycle infrastructure changes are needed to influence driving behavior in Baltimore to increase motorist compliance with the three-foot law. PMID:22664711
Real structures on almost-commutative spectral triples
Ćaćić, Branimir
2012-01-01
We refine the reconstruction theorem for almost-commutative spectral triples to a result for real almost-commutative spectral triples, clarifying, in the process, both concrete and abstract definitions of real commutative and almost-commutative spectral triples. In particular, we find that a real almost-commutative spectral triple algebraically encodes the commutative *-algebra of the base manifold in a canonical way, and that a compact oriented Riemannian manifold admits real (almost-)commut...
Non-commutative Nash inequalities
Kastoryano, Michael [NBIA, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Temme, Kristan [Institute for Quantum Information and Matter, California Institute of Technology, Pasadena California 91125 (United States)
2016-01-15
A set of functional inequalities—called Nash inequalities—are introduced and analyzed in the context of quantum Markov process mixing. The basic theory of Nash inequalities is extended to the setting of non-commutative L{sub p} spaces, where their relationship to Poincaré and log-Sobolev inequalities is fleshed out. We prove Nash inequalities for a number of unital reversible semigroups.
Commuting graphs of matrix algebras
The commuting graph of a ring R, denoted by Γ(R), is a graph whose vertices are all non- central elements of R and two distinct vertices x and y are adjacent if and only if xy = yx. The commuting graph of a group G, denoted by Γ(G), is similarly defined. In this paper we investigate some graph theoretic properties of Γ(Mn(F)), where F is a field and n ≥ 2. Also we study the commuting graphs of some classical groups such as GLn(F) and SLn(F). We show that Γ(Mn(F)) is a connected graph if and only if every field extension of F of degree n contains a proper intermediate field. We prove that apart from finitely many fields, a similar result is true for Γ(GLn(F)) and Γ(SLn(F)). Also we show that for two fields E and F and integers m, n ≥> 2, if Γ(Mm(E)) ≅ Γ(Mn(F)), then m = n and vertical bar E vertical bar = vertical bar F vertical bar. (author)
Street lighting disturbs commuting bats.
Stone, Emma Louise; Jones, Gareth; Harris, Stephen
2009-07-14
Anthropogenic disturbance is a major cause of worldwide declines in biodiversity. Understanding the implications of this disturbance for species and populations is crucial for conservation biologists wishing to mitigate negative effects. Anthropogenic light pollution is an increasing global problem, affecting ecological interactions across a range of taxa and impacting negatively upon critical animal behaviors including foraging, reproduction, and communication (for review see). Almost all bats are nocturnal, making them ideal subjects for testing the effects of light pollution. Previous studies have shown that bat species adapted to foraging in open environments feed on insects attracted to mercury vapor lamps. Here, we use an experimental approach to provide the first evidence of a negative effect of artificial light pollution on the commuting behavior of a threatened bat species. We installed high-pressure sodium lights that mimic the intensity and light spectra of streetlights along commuting routes of lesser horseshoe bats (Rhinolophus hipposideros). Bat activity was reduced dramatically and the onset of commuting behavior was delayed in the presence of lighting, with no evidence of habituation. These results demonstrate that light pollution may have significant negative impacts upon the selection of flight routes by bats. PMID:19540116
Public Bicycle Share Programs and Head Injuries
Pless, Barry; Moore, Lynne; Nathens, Avery B.; Hunte, Garth; Rivara, Frederick P.
2014-01-01
Objectives. We evaluated the effect of North American public bicycle share programs (PBSPs), which typically do not offer helmets with rentals, on the occurrence of bicycle-related head injuries. Methods. We analyzed trauma center data for bicycle-related injuries from 5 cities with PBSPs and 5 comparison cities. We used logistic regression models to compare the odds that admission for a bicycle-related injury would involve a head injury 24 months before PBSP implementation and 12 months afterward. Results. In PBSP cities, the proportion of head injuries among bicycle-related injuries increased from 42.3% before PBSP implementation to 50.1% after (P < .01). This proportion in comparison cities remained similar before (38.2%) and after (35.9%) implementation (P = .23). Odds ratios for head injury were 1.30 (95% confidence interval = 1.13, 1.67) in PBSP cities and 0.94 (95% confidence interval = 0.79, 1.11) in control cities (adjusted for age and city) when we compared the period after implementation to the period before. Conclusions. Results suggest that steps should be taken to make helmets available with PBSPs. Helmet availability should be incorporated into PBSP planning and funding, not considered an afterthought following implementation. PMID:24922150
Rail commuting duration and passenger stress.
Evans, Gary W; Wener, Richard E
2006-05-01
Over 100 million Americans commute to work every weekday. Little is known, however, about how this aspect of work, which may indeed be the most stressful aspect of the job for some, affects human health and well-being. The authors studied a sample of 208 male and female suburban rail commuters who took the train to Manhattan, New York. The greater the duration of the commute, the larger the magnitude of salivary cortisol elevations in reference to resting baseline levels, the less the commuter's persistence on a task at the end of the commute, and the greater the levels of perceived stress. These effects were not moderated by gender. Commuting stress is an important and largely overlooked aspect of environmental health. PMID:16719613
Non-commutativity in polar coordinates
Edwards, James P
2016-01-01
We reconsider the fundamental commutation relations for non-commutative $\\mathbb{R}^{2}$ described in polar coordinates with non-commutativity parameter $\\theta$. Previous analysis found that the natural transition from Cartesian coordinates to polars led to a representation of $\\left[\\hat{r}, \\hat{\\varphi}\\right]$ as an everywhere diverging series. We compute the Borel resummation of this series, showing that it can subsequently be extended throughout parameter space and hence provide an interpretation of this commutator. Our analysis provides a complete solution for arbitrary $r$ and $\\theta$ that reproduces the earlier calculations at lowest order. We compare our results to previous literature in the (pseudo-)commuting limit, finding a surprising spatial dependence for the coordinate commutator when $\\theta \\gg r^{2}$. We raise some questions for future study in light of this progress.
Commutative Hopf algebras of permutations and trees
Hivert, F.; Novelli, J. -C.; Thibon, J. -Y.
2005-01-01
We propose several constructions of commutative or cocommutative Hopf algebras based on various combinatorial structures, and investigate the relations between them. A commutative Hopf algebra of permutations is obtained by a general construction based on graphs, and its non-commutative dual is realized in three different ways, in particular as the Grossman-Larson algebra of heap ordered trees. Extensions to endofunctions, parking functions, set partitions, planar binary trees and rooted fore...
Product and Commutativity of Slant Toeplitz Operators
Chaomei LIU; Yufeng LU
2013-01-01
In this paper,the product and commutativity of slant Toeplitz operators are discussed.We show that the product of kth1-order slant Toeplitz operators and kth2-order slant Toeplitz operators must be a (k1k2)th-order slant Toeplitz operator except for zero operators,and the commutativity and essential commutativity of two slant Toeplitz operators with different orders are the same.
The Quantum Commutator of a Perfect Fluid
Roberts, Mark D.
1998-01-01
A perfect fluid is quantized by the canonical method. The constraints are found and this allows the Dirac brackets to be calculated. Replacing the Dirac brackets with quantum commutators formally quantizes the system. There is a momentum operator in the denominator of some coordinate quantum commutators. It is shown that it is possible to multiply throughout by this momentum operator. Factor ordering differences can result in a viscosity term. The resulting quantum commutator algebra is \\vspa...
Bicycling to school improves the cardiometabolic risk factor profile
Ostergaard, Lars; Børrestad, Line A B; Tarp, Jakob;
2012-01-01
To investigate whether bicycling to school improves cardiometabolic risk factor profile and cardiorespiratory fitness among children.......To investigate whether bicycling to school improves cardiometabolic risk factor profile and cardiorespiratory fitness among children....
On the stability of a bicycle on rollers
Cleary, Patricia A [Department of Geosciences, University of Wisconsin-Parkside, Kenosha, WI 53141 (United States); Mohazzabi, Pirooz, E-mail: pirooz.mohazzabi@uwp.edu [Department of Physics, University of Wisconsin-Parkside, Kenosha, WI 53141 (United States)
2011-09-15
Riding a bicycle on the newest form of indoor training, rollers, presents a unique experiment on bicycle stability. The stability factors eliminated by riding on rollers are discussed in terms of refined handling and control of the centre of mass on a bicycle. This paper is intended for undergraduate physics majors as well as any other general readership interested in the dynamics of bicycle stability.
On the Stability of a Bicycle on Rollers
Cleary, Patricia A.; Mohazzabi, Pirooz
2011-01-01
Riding a bicycle on the newest form of indoor training, rollers, presents a unique experiment on bicycle stability. The stability factors eliminated by riding on rollers are discussed in terms of refined handling and control of the centre of mass on a bicycle. This paper is intended for undergraduate physics majors as well as any other general…
An Analysis of Florida Physical Educators' Knowledge of Bicycle Laws
Connaughton, Daniel P.; Egberts, John B.; Spengler, J. O.; Zhang, James J.; Jin, Liyan
2012-01-01
Bicycling among youth is a popular activity, but like all modes of travel it is not without risk. Florida has a particularly high rate of bicycle-related fatalities and injuries. To reduce such risks, the Florida Department of Transportation and Florida Department of Education have developed a youth bicycle safety educational program (Florida…
Calculation of the commutator anomaly
It is well-known that, for the non-Abelian gauge theory coupled to the chiral fermions, which is described by a Lagrangian, the anomaly of the non-Abelian current is given by the descent form of the Chern-Simon five form; D*Ja = (-1/24π2)tr[d(AdA + 1/2A3)], where A = Aμdxμ = -itaAμadxμ. Recently, Faddeev argued that, for such an anomalous system, the gauge symmetry would be represented in a generalized sense of projective representation; V(g1)V(g2)Ψ(A) = exp[iα2(g1, g2; A)] X V(g1g2)Ψ(A), where Ψ(A) is the wave functional and the phase factor α2 depends on both the group elements and the gauge field configuration A. Here, it is convenient to consider the infinitesimal version of the above argument. The generator of infinitesimal gauge transformation in the temporal gauge A0 = 0 is given by Ga(x) = δiEia + gfabcAibEic - gΨ-barγ0taΨ, and the infinitesimal form of the previous product rule can be written as the equal time commutation relation; [Ga(x), Gb(y)] = ifabcGc(x)δ3(x-y) + ab(x,y,A), where is related to α2. In this equation, the first term is what is expected as the normal commutation relation of the generator, while the second term is an anomaly, which is designated here as the commutator anomaly. Then the present study concentrates on operations to determine the anomaly term. (Nogami, A.)
Successful Swiss solar bicycles in Australia
The article takes a look at the Swiss 'Spirit of Bike' team's success in the 'Power Challenge' race across Australia using solar-bicycles based on commercially available models. Apart from the sporting aspects of race, technical details on the cycles and their supply of solar power are given. Also, the history behind the success of the team is presented and the monitoring of man (and woman) and machine during the race is described. The article also discusses the electric bicycles that are commercially available and the potential of these energy-efficient vehicles in Switzerland
Kakde, Mahesh
2014-01-01
In this short note we partially answer a question of Fukaya and Kato by constructing a $q$-expansion with coefficients in a non-commutative Iwasawa algebra whose constant term is a non-commutative p-adic zeta function.
Commutative Moufang loops and alternative algebras
Grishkov, Alexander N.; Shestakov, Ivan P.
2008-01-01
We compute the orders of free commutative Moufand loops of exponent 3 with $n\\leq 7$ free generators and find embeddings of such loops into a loop of invertible elements of the free commutative alternative algebra with identity $x^3=0$.
Universal Lie algebra extensions via commutative structures
Yanovski, A B
2001-01-01
We consider some special type extensions of an arbitrary Lie algebra, which we call universal extensions. We show that these extensions are in one-to-one correspondence with finite dimensional associative commutative algebras. We also construct a special kind of these extensions, that correspond to a finite commutative monoids.
Commutativity and ideals in category crossed products
Öinert, Per Johan; Lundström, Patrik
2010-01-01
In order to simultaneously generalize matrix rings and group graded crossed products, we introduce category crossed products. For such algebras we describe the centre and the commutant of the coefficient ring. We also investigate the connection between on the one hand maximal commutativity of the...
Non-commutative Kerr black hole
Di Grezia, Elisabetta; Esposito, Giampiero
2009-01-01
This paper applies the first-order Seiberg-Witten map to evaluate the first-order non-commutative Kerr tetrad. The classical tetrad is taken to follow the locally non-rotating frame prescription. We also evaluate the tiny effect of non-commutativity on the efficiency of the Penrose process of rotational energy extraction from a black hole.
Happiness and Satisfaction with Work Commute
Olsson, Lars E.; Garling, Tommy; Ettema, Dick; Friman, Margareta; Fujii, Satoshi
2013-01-01
Research suggests that for many people happiness is being able to make the routines of everyday life work, such that positive feelings dominate over negative feelings resulting from daily hassles. In line with this, a survey of work commuters in the three largest urban areas of Sweden show that satisfaction with the work commute contributes to…
On the Skill of Balancing While Riding a Bicycle
Cain, Stephen M; Ashton-Miller, James A.; Perkins, Noel C.
2016-01-01
Humans have ridden bicycles for over 200 years, yet there are no continuous measures of how skill differs between novice and expert. To address this knowledge gap, we measured the dynamics of human bicycle riding in 14 subjects, half of whom were skilled and half were novice. Each subject rode an instrumented bicycle on training rollers at speeds ranging from 1 to 7 m/s. Steer angle and rate, steer torque, bicycle speed, and bicycle roll angle and rate were measured and steering power calcula...
Children and bicycles: what is really happening? Studies of fatal and non-fatal bicycle injury.
Acton, C. H.; Thomas, S; Nixon, J. W.; Clark, R; Pitt, W R; Battistutta, D.
1995-01-01
OBJECTIVES: The objectives of the study were to ascertain the causes of accidents, injuries, and deaths in children who ride bicycles. Fatality and injury rates were also studied in order to compare with other studies. METHODS: Two studies of children were undertaken in children aged less than 15 years. In the first (retrospective fatality study), children who died as a result of a bicycle incident during the period 1981-92 were reviewed. In the second (prospective injury study) data were obt...
Solutions to the Triangular Bicycle Flags Problem
Hartweg, Kim
2005-01-01
Students in a fifth-grade general education class and a second-grade gifted class participated in the Triangular Bicycle Flags problem. The results indicated that providing students with geometric experiences at the correct van Hiele level is necessary for helping students move from one level of understanding to the next.
What do we know about bicycle helmets?
Bogerd, C.P. Halldin, P. Houtenbos, M. Otte, D. Rossi, R.M. Walker, L. Willinger, R. & Shinar, D.
2012-01-01
Cycling is an excellent sustainable alternative to driving for many journeys. But cyclists have fewer safety options than car-users, with a helmet being the main safety device that is available. However, there are indications that increasing bicycle helmet usage through legislation causes confoundin
Bicyclic semigroups of left I-quotients
Ghroda, Nassraddin
2011-01-01
In this article we study left I-orders in the bicyclic monoid $\\mathcal{B}$. We give necessary and sufficient conditions for a subsemigroup of $\\mathcal{B}$ to be a left I-oreder in $\\mathcal{B}$. We then prove that any left I-order in $\\mathcal{B}$ is straight.
Inferring Passenger Type from Commuter Eigentravel Matrices
Legara, Erika Fille
2015-01-01
A sufficient knowledge of the demographics of a commuting public is essential in formulating and implementing more targeted transportation policies, as commuters exhibit different ways of traveling. With the advent of the Automated Fare Collection system (AFC), probing the travel patterns of commuters has become less invasive and more accessible. Consequently, numerous transport studies related to human mobility have shown that these observed patterns allow one to pair individuals with locations and/or activities at certain times of the day. However, classifying commuters using their travel signatures is yet to be thoroughly examined. Here, we contribute to the literature by demonstrating a procedure to characterize passenger types (Adult, Child/Student, and Senior Citizen) based on their three-month travel patterns taken from a smart fare card system. We first establish a method to construct distinct commuter matrices, which we refer to as eigentravel matrices, that capture the characteristic travel routines...
Safety effects of permanent running lights for bicycles
Madsen, Jens Chr. Overgaard; Andersen, T.; Lahrmann, Harry
2013-01-01
3845 cyclists was carried out in Odense, Denmark in order to examine, if permanent running lights mounted to bicycles would improve traffic safety for cyclists. The permanent running lights were mounted to 1845 bicycles and the accident rate was recorded through 12 months for this treatment group and...... 2000 other bicyclists, the latter serving as a control group without bicycle running lights. The safety effect of the running lights is analysed by comparing incidence rates – number of bicycle accidents recorded per man-month – for the treatment group and the control group. The incidence rate......, including all recorded bicycle accidents with personal injury to the participating cyclist, is 19% lower for cyclists with permanent running lights mounted; indicating that the permanent bicycle running light significantly improves traffic safety for cyclists. The study shows that use of permanent bicycle...
Canonical commutation relation preserving maps
We study maps preserving the Heisenberg commutation relation ab-ba=1. We find a one-parameter deformation of the standard realization of the above algebra in terms of a coordinate and its dual derivative. It involves a non-local 'coordinate' operator while the dual 'derivative' is just the Jackson finite-difference operator. Substitution of this realization into any differential operator involving x and d/dx results in an isospectral deformation of a continuous differential operator into a finite-difference one. We extend our results to the deformed Heisenberg algebra ab-qba=1. As an example of potential applications, various deformations of the Hahn polynomials are briefly discussed. (author)
Weaving commutators: beyond Fock space
Arzano, Michele
2012-01-01
The symmetrization postulate and the associated Bose/Fermi (anti)-commutators for field mode operators are among the pillars on which local quantum field theory lays its foundations. They ultimately determine the structure of Fock space and are closely connected with the local properties of the fields and with the action of symmetry generators on observables and states. We here show that the quantum field theory describing relativistic particles coupled to three dimensional Einstein gravity as a topological defect must be constructed using a deformed algebra of creation and annihilation operators. This reflects a non-trivial group manifold structure of the classical momentum space and a modification of the Leibniz rule for the action of symmetry generators governed by Newton's constant. We outline various arguments suggesting that, at least at the qualitative level, these three-dimensional results could also apply to real four-dimensional world thus forcing us to re-think the ordinary multiparticle structure ...
Traffic conflicts on bicycle paths: a systematic observation of behaviour from video
Horst, A.R.A. van der; Goede, M. de; Hair-Buijssen, S.H.H.M. de; Methorst, R.
2014-01-01
In The Netherlands, on bicycle paths, single-bicycle accidents, bicycle-bicycle and bicycle-moped accidents constitute a considerable share of all bicyclist injuries. Over three quarters of all hospitalised bicyclist victims in the Netherlands cannot be directly related to a crash with motorised tra
On the interrelations between migration and commuting
Lukić Vesna
2013-01-01
Full Text Available In this paper, we emphasise the significance of studying the interrelations between commuting and migration. The aim of the paper is to point out the factors which affect these interrelations (demographic and socio-economic characteristics of migrants and commuters, labour market, real estate market, information, life style, etc., with the special emphasis on the role of commuting distance onto the chosen mobility type. Besides theorethical frameworks and results of the selected foreign researches up to date, the overview of research of interrelations between migration and commuting in Serbia has also been presented. While earlier studies conducted by Gawryszenski (1978, Termote (1980 and Reitsma&Vergoossen (1987 pointed to the replacement of migration types between each other within country, in recent literature the interaction between migration and commuting has been studied in a trans-boundary context of the contemporary EU. Modern trend of long distance commuting instead of migration and the concept of substitution/replacement regarding migration and commuting have also been discussed. In Serbia, there is a positive correlation between commuting outflows and immigration in rural settlements of Vojvodina province. Namely, commuting and migration are complement, which is the characteristic of both processes sub-urbanisation and ex-urbanisation (Lukić, 2012. In addition to ownership of real estate and previous migration experience, marital status influenced the chosen mobility type in Serbia as well. Adjustment to changes of Serbian labour market is mostly conducted via migration (Miletić, Lukić, Miljanović, 2011. Interrelations between migration and commuting are very significant due to the tendency of transformation of some commuters into migrants. This process has its consequences, both on demographic as well as the overall socio-economic development of the area of commuters’ origin and destination. However, even though the surveys
Two-dimensional black holes and non-commutative spaces
We study the effects of non-commutative spaces on two-dimensional black hole. The event horizon of two-dimensional black hole is obtained in non-commutative space up to second order of perturbative calculations. A lower limit for the non-commutativity parameter is also obtained. The observer in that limit in contrast to commutative case see two horizon
Exploratory mapping of commuter flows in England and Wales
Nielsen, Thomas Alexander Sick; Harder, Henrik
2008-01-01
The paper uses the origin–destination commute data published from the 1991 and 2001 Census to explore the developments in commuting and interaction patterns within England and Wales. Focus is on the geographical variations and a map of commuter flows is presented. Commuting is stretched out along a...
Theurel, J; Theurel, A; Lepers, R
2012-01-01
The present study compared the physiological responses and the subsequent cognitive performance when riding an electrically assisted (EB) versus a classical (CB) bicycle. Oxygen uptake, heart rate and leg extensor muscles electromyographic (EMG) activity were recorded in 10 subjects during a 30-min intermittent cycling exercise performed with EB versus CB. Cognitive performance was evaluated by a mail sorting test, performed at rest and after each cycling session. Averaged oxygen uptake and heat rate were significantly (P cycling than during CB cycling. The EMG activities of the vastus lateralis, rectus femoris and gastrocnemius medialis muscles were significantly (P cycling than during EB cycling. The time to complete the mail sorting test was significantly (P cycling than after CB cycling. Because EB cycling reduced muscle strains and physiological stress, it might offer benefits for those using bicycles in their work, such as postal workers and police officers. STATEMENT OF RELEVANCE: This study compared physiological and cognitive responses when riding an electrically assisted versus a classical bicycle. The results showed that the electrically assisted bicycle led to reduced muscle strains and physiological stress and, therefore, might offer benefits for those using bicycles in their work, such as postal workers and police officers. PMID:22506555
Fatal falls from bicycles: a case report.
Venara, A; Mauillon, D; Gaudin, A; Rouge-Maillart, C; Jousset, N
2013-03-10
Though rare occurrences, fatal falls from bicycles are generally linked to the absence of a protective helmet and/or a collision with another vehicle. The case presented here is exceptional due to its circumstances and the consequences of the accident: a fall with no obstacle at a low speed that brought about multiple traumas and the death of a cyclist wearing a protective helmet. Comparing this against a review of cyclist accidentology literature, this case is unique. The increased use of autopsy in terms of forensic accidentology is to be encouraged so as not to misunderstand the possibility of such lesion-based consequences following a simple fall from a bicycle. PMID:23312586
Giancarlo Bacchieri
2005-10-01
Full Text Available Um estudo transversal de base-populacional foi realizado em Pelotas, sul do Brasil, objetivando pesquisar os determinantes e padrões de utilização da bicicleta como modo de transporte para o trabalho. Foram também descritos os acidentes ocorridos nos últimos 12 meses no deslocamento de ida e volta para o trabalho e a utilização de equipamentos de segurança na bicicleta. A amostra incluiu 1.705 trabalhadores com 15 anos ou mais de idade, residentes na zona urbana, que utilizavam modos de transporte para o trabalho. Análises bruta e ajustada foram realizadas por meio de regressão de Poisson, considerando o efeito do delineamento. A prevalência de utilização da bicicleta foi de 17,2% (IC95%: 15,4-19,0. Trabalhadores homens, com baixa escolaridade e nível econômico mais baixo apresentaram as maiores prevalências. Menos de 1,0% das bicicletas possuía os equipamentos de segurança exigidos pelo Código de Trânsito Brasileiro e 15,0% não tinham freios. Aproximadamente 6,0% desses trabalhadores sofreram acidentes de trânsito com lesões corporais nos últimos 12 meses. Concluímos que trabalhadores que utilizam bicicleta como modo de transporte são prioritários para intervenções preventivas relacionadas a acidentes de trânsito.A population-based cross-sectional study was conducted in Pelotas, southern Brazil, focusing on the determinants and patterns of bicycle use as a mode of commuting by workers. Accidents during commuting and use of safety equipment were also studied. The sample included 1,705 workers (> 15 years of age living in the urban area of Pelotas and using various modes of transportation during commuting. Crude and adjusted analyses were performed using Poisson regression, taking the design effect into account. Prevalence of bicycle use was 17.2% (95%CI: 15.4%-19.0%. Male workers and those with low schooling and low income presented higher prevalence. Less than 1.0% of the bicycles featured the safety equipment
Maximum Estrada Index of Bicyclic Graphs
Wang, Long; Wang, Yi
2012-01-01
Let $G$ be a simple graph of order $n$, let $\\lambda_1(G),\\lambda_2(G),...,\\lambda_n(G)$ be the eigenvalues of the adjacency matrix of $G$. The Esrada index of $G$ is defined as $EE(G)=\\sum_{i=1}^{n}e^{\\lambda_i(G)}$. In this paper we determine the unique graph with maximum Estrada index among bicyclic graphs with fixed order.
The Optimal Choice of Commuting Speed: Consequences for Commuting Time, Distance and Costs
van Ommeren, Jos; Dargay, Joyce
2004-01-01
This discussion paper resulted in a publication in the 'Journal of Transport Economics and Policy', 2006, 40(2), 279-296. In this paper, we derive a structural model for commuting speed. We presume that commuting speed is chosen to minimise commuting costs, which encompass both monetary and time costs. At faster speed levels, the monetary costs increase, but the time costs fall. Using data from Great Britain, we demonstrate that the income elasticity of commuting speed is 0.126. The ratio of ...
Covariant non-commutative space-time
Heckman, Jonathan J.; Verlinde, Herman
2015-05-01
We introduce a covariant non-commutative deformation of 3 + 1-dimensional conformal field theory. The deformation introduces a short-distance scale ℓp, and thus breaks scale invariance, but preserves all space-time isometries. The non-commutative algebra is defined on space-times with non-zero constant curvature, i.e. dS4 or AdS4. The construction makes essential use of the representation of CFT tensor operators as polynomials in an auxiliary polarization tensor. The polarization tensor takes active part in the non-commutative algebra, which for dS4 takes the form of so (5, 1), while for AdS4 it assembles into so (4, 2). The structure of the non-commutative correlation functions hints that the deformed theory contains gravitational interactions and a Regge-like trajectory of higher spin excitations.
Covariant non-commutative space–time
Jonathan J. Heckman
2015-05-01
Full Text Available We introduce a covariant non-commutative deformation of 3+1-dimensional conformal field theory. The deformation introduces a short-distance scale ℓp, and thus breaks scale invariance, but preserves all space–time isometries. The non-commutative algebra is defined on space–times with non-zero constant curvature, i.e. dS4 or AdS4. The construction makes essential use of the representation of CFT tensor operators as polynomials in an auxiliary polarization tensor. The polarization tensor takes active part in the non-commutative algebra, which for dS4 takes the form of so(5,1, while for AdS4 it assembles into so(4,2. The structure of the non-commutative correlation functions hints that the deformed theory contains gravitational interactions and a Regge-like trajectory of higher spin excitations.
Opportunities and benefits. [commuter air travel
Galloway, T. L.
1983-01-01
The service characteristics and changes affecting commuter airline operations are summarized. Community and passenger considerations are addressed and the benefits identified in NASA-sponsored aircraft studies are discussed.
2000-01-01
Imagine you have just arrived at CERN. You are from Russia or Japan and have no car but you do need to get around and do not like depending on public transport. What do you do? You go to the EP Service Point (Building 124) and meet Boris Cabaud to get a CERN bicycle. Use of the bicycle is free but you have to fill in an application form which needs to be signed by your Group or Division Secretary. Then the application is filled in, you are put on the waiting list and it might take you from one to four weeks to get your bike depending on the season. Normally the bikes are only for Users in the EP division as they are paid for by the EP budget, says Boris, but some other divisions have made arrangements to cover the costs. Boris takes care of 350 bicycles at present. Each bike can be lent for maximum one year. During the winter the bikes can be stored in building 301 as it is difficult to ride them in the snow. If a bike is broken or lost all costs will be billed to the group or team account of the bo...
Applying riding-posture optimization on bicycle frame design.
Hsiao, Shih-Wen; Chen, Rong-Qi; Leng, Wan-Lee
2015-11-01
Customization design is a trend for developing a bicycle in recent years. Thus, the comfort of riding a bike is an important factor that should be paid much attention to while developing a bicycle. From the viewpoint of ergonomics, the concept of "fitting object to the human body" is designed into the bicycle frame in this study. Firstly, the important feature points of riding posture were automatically detected by the image processing method. In the measurement process, the best riding posture was identified experimentally, thus the positions of feature points and joint angles of human body were obtained. Afterwards, according to the measurement data, three key points: the handlebar, the saddle and the crank center, were identified and applied to the frame design of various bicycle types. Lastly, this study further proposed a frame size table for common bicycle types, which is helpful for the designer to design a bicycle. PMID:26154206
Active commuting to school in Portuguese adolescents: Using PALMS to detect trips
Pizarro, Andreia Nogueira; Schipperijn, Jasper; Andersen, Henriette Bondo;
2016-01-01
Abstract The declining levels of physical activity (PA) have led to active commuting to school (ACS) being seen as a key strategy to increase PA levels in school-aged children. In Portugal, no data exists on the patterns of this behavior, an essential step for developing evidence-based and...... effective interventions. The purpose of this study is to explore the travel to school behavior using an objective methodology. Methods 155 adolescents (mean age 15.9±1.1 years) wore an accelerometer and a GPS for 7 consecutive days. Home and school addresses were geocoded to identify home-school trips. The...... web-based tool PALMS was used to combine GPS and accelerometer data, categorize Moderate to Vigorous Physical Activity (MVPA) and classify trip mode of home-school trips into: walking, bicycling or vehicle. Results 609 trips were identified as home-school trips. Walking was the most frequent trip mode...
Homotopy Invariant Commutative Algebra over fields
Greenlees, J. P. C.
2016-01-01
These notes illustrates the power of formulating ideas of commutative algebra in a homotopy invariant form. They can then be applied to derived categories of rings or ring spectra. These ideas are powerful in classical algebra, in representation theory of groups, in classical algebraic topology and elsewhere. The notes grew out of a series of lectures given during the `Interactions between Representation Theory, Algebraic Topology and Commutative Algebra' (IRTATCA) at the CRM (Barcelona) in S...
How do motorways shape commuting patterns?
Hovgesen, Henrik Harder; Nielsen, Thomas Alexander Sick
2004-01-01
urbanization and spatial interaction patterns in the last 20 years. This paper presents results on how the building of the motorway network has shaped spatial interactions patterns in Denmark over a ten year period. The question asked is how travel time reductions and changing motorway access is related to...... change in the commute pattern. And whether the relations between these factors and commuting are a new course of development or a continuation of past trends....
Studying commuting behaviours using collaborative visual analytics
Beecham, R.; J. Wood; Bowerman, A.
2014-01-01
Mining a large origin–destination dataset of journeys made through London’s Cycle Hire Scheme (LCHS), we develop a technique for automatically classifying commuting behaviour that involves a spatial analysis of cyclists’ journeys. We identify a subset of potential commuting cyclists, and for each individual define a plausible geographic area representing their workplace. All peak-time journeys terminating within the vicinity of this derived workplace in the morning, and originating from this ...
Black Hole with Non-Commutative Hair
Klimcik, C; Kolnik, P.; Pompos, A.
1993-01-01
The specific nonlinear vector $\\sigma$-model coupled to Einstein gravity is investigated. The model arises in the studies of the gravitating matter in non-commutative geometry. The static spherically symmetric spacetimes are identified by direct solving of the field equations. The asymptotically flat black hole with the ``non-commutative'' vector hair appears for the special choice of the integration constants, giving thus another counterexample to the famous ``no-hair'' theorem.
New commutation relations for quantum gravity
Soo, Chopin
2016-01-01
A new set of fundamental commutation relations for quantum gravity is presented. The basic variables are the eight components of the unimodular part of the spatial dreibein and eight SU(3) generators which correspond to Klauder's momentric variables. The commutation relations are not canonical, but they have well defined group theoretical meanings. All fundamental entities are dimensionless; and quantum wave functionals are preferentially selected to be in the dreibein representation.
Fertility and commuting behaviour in Germany
Johannes Huinink; Michael Feldhaus
2012-01-01
"Fertility behavior is closely related to other dimensions of the individual life course, which are strongly interrelated themselves. Regarding the impact of job-related spatial mobility, empirical findings show a negative correlation between having children and commuting, particularly for women. Up to now, fertility intentions have not been thoroughly investigated in this respect. Longitudinal studies are lacking, too. In this paper, the effects of commuting arrangements of men and women on ...
Non-commutativity measure of quantum discord
Guo, Yu
2016-01-01
Quantum discord is a manifestation of quantum correlations due to non-commutativity rather than entanglement. Two measures of quantum discord by the amount of non-commutativity via the trace norm and the Hilbert-Schmidt norm respectively are proposed in this paper. These two measures can be calculated easily for any state with arbitrary dimension. It is shown by several examples that these measures can reflect the amount of the original quantum discord. PMID:27122226
Non-commutativity measure of quantum discord.
Guo, Yu
2016-01-01
Quantum discord is a manifestation of quantum correlations due to non-commutativity rather than entanglement. Two measures of quantum discord by the amount of non-commutativity via the trace norm and the Hilbert-Schmidt norm respectively are proposed in this paper. These two measures can be calculated easily for any state with arbitrary dimension. It is shown by several examples that these measures can reflect the amount of the original quantum discord. PMID:27122226
Zhao, De; Wang, Wei; Li, Zhibin; Shan, Xiaonian; Sun, Xin
Bicycle facilities are quite common in China but there are not enough quantitative methods to evaluate the Level of Service (LOS) of bicycle roadways. The number of passing events, which considers the interactions between bicyclists, has been proved to be a proper indicator for evaluating bicycle LOS under the special traffic and roadway conditions in China. The primary objective of this study is to propose a model considering the delay effects of passing events and rider's overtaking motivation. Field data was collected on South Zhongshan Road and Huaihai Road in Nanjing city of China with 639 bicyclists investigated. Then a new mathematical model was built to evaluate those effects through probability and regression analyses. It was found that the delay effect of passing events and rider's overtaking motivation are significant influencing factors which cannot be omitted. Correlation test shows the fitted relationship is greater between the model prediction and field data comparing with the previous model.
Will a bicycle friendly policy make passenger travel more sustainably?
Christensen, Linda; Jensen, Thomas Christian
2009-01-01
The purpose of this paper is to analyse the possibility to transfer a larger part of the short car trips to walking or bicycling in order to obtain environmental and health benefits. The project contains a logistic choice model used to explain which circumstances are particularly important for choosing walking and bicycling, and how very different instruments can promote walking and bicycling at the expense of short car trips. Furthermore, the paper describes the most important factors when c...
Technical analysis and market study of electric bicycles
Matasyan, Artur
2015-01-01
This thesis project was done in collaboration with a Prismattery LLC, which is based in Tallinn, Estonia and is interested in entering the market of electric bicycles. For that reason in this report a detailed study concerning the market of electrical bicycles, its current situation and trends were performed and a promising target market was indicated. The market study showed that although in different countries the specifications and preferred types of electric bicycles may vary,...
Bicycle-Sharing System Analysis and Trip Prediction
Zhang, Jiawei; Pan, Xiao; Li, Moyin; Yu, Philip S.
2016-01-01
Bicycle-sharing systems, which can provide shared bike usage services for the public, have been launched in many big cities. In bicycle-sharing systems, people can borrow and return bikes at any stations in the service region very conveniently. Therefore, bicycle-sharing systems are normally used as a short-distance trip supplement for private vehicles as well as regular public transportation. Meanwhile, for stations located at different places in the service region, the bike usages can be qu...
Non-commutativity in the brain.
Tweed, D B; Haslwanter, T P; Happe, V; Fetter, M
1999-05-20
In non-commutative algebra, order makes a difference to multiplication, so that a x b not equal to b x a. This feature is necessary for computing rotary motion, because order makes a difference to the combined effect of two rotations. It has therefore been proposed that there are non-commutative operators in the brain circuits that deal with rotations, including motor circuits that steer the eyes, head and limbs, and sensory circuits that handle spatial information. This idea is controversial: studies of eye and head control have revealed behaviours that are consistent with non-commutativity in the brain, but none that clearly rules out all commutative models. Here we demonstrate non-commutative computation in the vestibulo-ocular reflex. We show that subjects rotated in darkness can hold their gaze points stable in space, correctly computing different final eye-position commands when put through the same two rotations in different orders, in a way that is unattainable by any commutative system. PMID:10353248
Non-commutative standard model: model building
A non-commutative version of the usual electro-weak theory is constructed. We discuss how to overcome the two major problems: (1) although we can have non-commutative U(n) (which we denote by U*(n)) gauge theory we cannot have non-commutative SU(n) and (2) the charges in non-commutative QED are quantized to just 0,±1. We show how the latter problem with charge quantization, as well as with the gauge group, can be resolved by taking the U*(3) x U*(2) x U*(1) gauge group and reducing the extra U(1) factors in an appropriate way. Then we proceed with building the non-commutative version of the standard model by specifying the proper representations for the entire particle content of the theory, the gauge bosons, the fermions and Higgs. We also present the full action for the non-commutative standard model (NCSM). In addition, among several peculiar features of our model, we address the inherentCP violation and new neutrino interactions. (orig.)
Potential risk and its influencing factors for separated bicycle paths.
Xu, Cheng; Yang, Ying; Jin, Sheng; Qu, Zhaowei; Hou, Lei
2016-02-01
In this paper, we propose two potential risk indicators to define and evaluate the safety of bicycle path at the microscopic level. Field bicycle data were collected from three survey sites under different traffic conditions. These two risk indicators based on speed dispersion were proposed and calculated during each 5-min interval. The risk influences of various widths of bicycle path and traffic conditions were analyzed by using one-way ANOVA. We further proposed a generalized linear model (GLM) for modeling and analyzing the relationships between bicycle risks and v/c ratio and percentages of electric bicycles, male cyclists, young cyclists, and loaded cyclists. The stepwise regression models were applied for determination of coefficients. The results show that the influences of gender and age of cyclists on potential risks are not significant. The risks increase with the width of bicycle path and percentage of electric bicycles, while only for wider bicycle path (4-lane case in this study), the risks are associated with whether or not cyclists are loaded. The findings could contribute for analysis and evaluation of the safety for bicycle path. PMID:26647016
Qiu, Jianjun
2013-01-01
In this paper, the Composition-Diamond lemma for commutative algebras with multiple operators is established. As applications, the Gr\\"obner-Shirshov bases and linear bases of free commutative Rota-Baxter algebra, free commutative $\\lambda$-differential algebra and free commutative $\\lambda$-differential Rota-Baxter algebra are given, respectively. Consequently, these three free algebras are constructed directly by commutative $\\Omega$-words.
Fertility and Commuting Behaviour in Germany
Johannes Huinink
2012-12-01
Full Text Available Fertility behaviour is closely related to other dimensions of the individual life course, which are strongly interrelated themselves. Regarding the impact of job-related spatial mobility, empirical findings show a negative correlation between having children and commuting, particularly for women. Up to now, fertility intentions have not been thoroughly investigated in this respect. Longitudinal studies are lacking, too. In this paper, the effects of commuting arrangements of men and women on the intention of having a child within the next two years as well as the probability of realising this intention are addressed. The assumption is, that after accounting for other important factors (employment status, level of qualification, type of consensual union, number of children, residential mobility, medium- and long-distance commuting is negatively related to the fertility intention of women and its realisation. For men, effects are assumed to be nonexistent or even slightly positive. Longitudinal data from the first three waves of the German “Panel Analysis of Intimate Relationships and Family Dynamics” (pairfam are used to test the hypotheses. Firstly, a cross-sectional, multivariate probit-regression (with correlated errors on the intention to have a child within two years, on being childless and on medium- and long- distance commuting is applied. The model shows no significant correlation between commuting and the intention to have a child; it does however show a correlation between medium- and long distance commuting and the probability of women to be childless. Secondly, a longitudinal difference model on changing fertility intentions between panel wave 1 and wave 3 is estimated. For women, a positive effect can be found of interrupting medium- and long-distance commuting or, surprisingly, continuing medium- and long-distance commuting on the intention to have a child within two years. Thirdly, for men and women who reported a fertility
Sidsel L Domazet
Full Text Available To examine objectively measured physical activity level, organized sports participation and active commuting to school in relation to mathematic performance and inhibitory control in adolescents.The design was cross-sectional. A convenient sample of 869 sixth and seventh grade students (12-14 years was invited to participate in the study. A total of 568 students fulfilled the inclusion criteria and comprised the final sample for this study. Mathematic performance was assessed by a customized test and inhibitory control was assessed by a modified Eriksen flanker task. Physical activity was assessed with GT3X and GT3X+ accelerometers presented in sex-specific quartiles of mean counts per minute and mean minutes per day in moderate-to-vigorous physical activity. Active commuting and sports participation was self-reported. Mixed model regression was applied. Total physical activity level was stratified by bicycling status in order to bypass measurement error subject to the accelerometer.Non-cyclists in the 2nd quartile of counts per minute displayed a higher mathematic score, so did cyclists in the 2nd and 3rd quartile of moderate-to-vigorous physical activity relative to the least active quartile. Non-cyclists in the 3rd quartile of counts per minute had an improved reaction time and cyclists in the 2nd quartile of counts per minute and moderate-to-vigorous physical activity displayed an improved accuracy, whereas non-cyclists in the 2nd quartile of counts per minute showed an inferior accuracy relative to the least active quartile. Bicycling to school and organized sports participation were positively associated with mathematic performance.Sports participation and bicycling were positively associated with mathematic performance. Results regarding objectively measured physical activity were mixed. Although, no linear nor dose-response relationship was observed there was no indication of a higher activity level impairing the scholastic or cognitive
Dias Batista, Edgard
2010-01-01
Bicycle-sharing programs are a new trend in urban transportation. The main difference of a bicycle-sharing program with a regular bicycle rental is that is possible to get a bicycle in one station and return it in any other station. There are many models of bicycle sharing, each model with its pros and cons. This study analyzes the bicycle-sharing models in order to build a proposal of a bicycle-sharing program suitable for Brazilian median cities. The study begins with an overview of bicycle...
On the Commuting Graph Of Non-commutative Rings of order( p^nq
Ebrahim Vatandoost
2014-07-01
Full Text Available Let $R$ be a non-commutative ring with unity. The commuting graphof $R$ denoted by $\\Gamma(R$, is a graph with vertex set$R\\setminus Z(R$ and two vertices $a$ and $b$ are adjacent iff$ab=ba$. In this paper, we consider the commuting graph of non-commutativerings of order $pq $ and $p^2q$ with $Z(R=0$ and non-commutative rings withunity of order $p^3q$. It is proved that $C_R(a$ is a commutative ring for every$0 \
Bicycle Helmet Laws are Associated with a Lower Fatality Rate from Bicycle-Motor Vehicle Collisions
Meehan, William P.; Lee, Lois K.; Fischer, Christopher M.; Mannix, Rebekah C.
2013-01-01
Objective To assess the association between bicycle helmet legislation and bicycle-related deaths sustained by children involved in bicycle-motor vehicle collisions. Study design We conducted a cross sectional study of all bicyclists aged 0-16 years included in the Fatality Analysis Reporting System (FARS) who died between January 1999 and December 2010. We compared fatality rates per age-specific state populations between states with helmet laws and those without helmet laws. We used a clustered Poisson multivariate regression model to adjust for factors previously associated with rates of motor vehicle fatalities: elderly driver licensure laws, legal blood alcohol limit ( 0.08 between states with helmet laws and those without helmet laws. The mean unadjusted rates of fatalities were lower in states with helmet laws (2.0/1,000,000 vs. 2.5/1,000,000; p= 0.03). After adjusting for potential confounding factors, states with mandatory helmet laws continued to be associated with a lower rate of fatalities (adjusted Incidence Rate Ratio 0.84; 95% CI 0.70, 0.98). Conclusions Bicycle helmet safety laws are associated with a lower incidence of fatalities among child bicyclists involved in motor vehicle collisions. PMID:23706604
Commutative deductive systems of pseudo BCK-algebras
Ciungu, Lavinia Corina
2016-01-01
In this paper we generalize the axiom systems given by M. Pa{\\l}asi\\'nski, B. Wo\\'zniakowska and by W.H. Cornish for commutative BCK-algebras to the case of commutative pseudo BCK-algebras. A characterization of commutative pseudo BCK-algebras is also given. We define the commutative deductive systems of pseudo BCK-algebras and we generalize some results proved by Yisheng Huang for commutative ideals of BCI-algebras to the case of commutative deductive systems of pseudo BCK-algebras. We prove...
Connections between migrations and commuting in Vojvodina
Lukić Vesna
2012-01-01
Full Text Available Various forms of population mobility are usually studied independently and thus lacking information if there is a connection between migration processes and if so, whether it is positive or negative. Based on the correlation method, this paper presents a study of the relationship between migration and commuting by the example of Vojvodina. Population and economic activities in Vojvodina are unevenly distributed and mainly concentrated to certain areas. Considering that the majority of rural population is no longer engaged in agriculture and that there are not enough local jobs in rural areas, numerous rural residents commute to work to cities. So, the majority of commuting flows in Vojvodina are flows of labour force from rural to urban areas. Results of statistical analysis, based on data about migrations to rural settlements of Vojvodina and data about divergent commuters, have shown a positive correlation between the two types of population mobility for all observed settlements (defined as addition, and that a significant proportion of migration variations can be explained by variations in the scope of commuting flows.
Dynamics and local policy in labour commuting
Samo Drobne
2012-01-01
Full Text Available Background: In the paper, the influence of the selected parameters, which are population, travel time to work by car, employment rate and average gross earnings, to labour commuting flows in Slovenia is analysed for the period 2000 – 2009. Furthermore, the dynamics of the analysed parameters have been studied to be implemented in the local policy application. Objectives: The main goal of this research has been to study the stickiness and attractiveness of Slovenian municipalities regarding the analysed parameters to support local labour commuting policy. Methods/Approach: The influence of the analysed parameters to the labour commuting flows has been studied in the extended gravity model. The change of the influence of parameters on commuting flows has been studied separately for each year in the analysed period. Additionally, the calculation of the extended gravity model has been performed for the whole analysed period. Results: The results show that the analysed parameters more attracted than dispatched the inter-municipal labour commuting flows in Slovenia in the study period. The results of the study of the dynamics of the analysed parameters have been implemented in the case study at the local level. Conclusions: The results provide the important empirical contribution to physical planners at the state, regional and/or local level for creating development policies. The results show that some factors in the gravity model can be compensated with the change of the others and vice-versa.
On Wiener polarity index of bicyclic networks
Ma, Jing; Shi, Yongtang; Wang, Zhen; Yue, Jun
2016-01-01
Complex networks are ubiquitous in biological, physical and social sciences. Network robustness research aims at finding a measure to quantify network robustness. A number of Wiener type indices have recently been incorporated as distance-based descriptors of complex networks. Wiener type indices are known to depend both on the network’s number of nodes and topology. The Wiener polarity index is also related to the cluster coefficient of networks. In this paper, based on some graph transformations, we determine the sharp upper bound of the Wiener polarity index among all bicyclic networks. These bounds help to understand the underlying quantitative graph measures in depth.
Bicycle braking friction measurements on winter roads
Rekilä, Katja
2015-01-01
This master’s thesis study has been carried out during a student exchange in the Norwegian University of science and technology in the Research Centre for Winter maintenance. The master’s thesis consists of two parts: I) a process report and II) a manuscript for a scientific paper. In addition, appendix is marked as part III. Bicycling is considered an attractive way of traveling since it improves health, is flexible and often fastest mode of travelling in urban areas. Therefore it is bec...
Solar Electric Bicycle Body Modeling and Simulation
Zhikun Wang
2013-10-01
Full Text Available A new solar electric bicycle design and study were carried out on in this paper. Application of CAD technology to establish three-dimension geometric model, using the kinetic analysis on the frame and other parts for numerical simulation and static strength analysis for the vehicle model design, virtual assembly, complete frame dynamics analysis and vibration analysis, with considering other factors, first on the frame structure improvement, second on security of design calculation analysis and comparison, finally get the ideal body design.
Arizona Traffic Safety Education, K-8. Bicycle Safety, Grade 3.
Mesa Public Schools, AZ.
One in a series designed to assist Arizona elementary and junior high school teachers in developing children's traffic safety skills, this curriculum guide for grade 3 contains seven lessons on bicycles and an appendix on conducting a bicycle rodeo. Introductory information provided for the teacher includes basic highway safety concepts, stressing…
77 FR 39927 - Vehicles and Traffic Safety-Bicycles
2012-07-06
... bicycle operator subject to most of the other traffic regulations in Part 4. 52 FR 10675, April 2, 1987... Responses to Public Comments The NPS published the proposed rule at 73 FR 76987 (December 18, 2008) and a... the special regulation requirement to ensure maximum public input on decisions to allow bicycle use...
Bicycle facilities on road segments and intersections of distributor roads.
2008-01-01
A sustainably safe road environment requires bicycle facilities that separate motorized traffic from relatively vulnerable road users like cyclists. Research indicates that on distributor roads the road sections with adjoining or separate bicycle tracks are safer than the road sections without any b
Bicycle Freewheeling with Air Drag as a Physics Experiment
Janssen, Paul; Janssens, Ewald
2015-01-01
To familiarize first-year students with the important ingredients of a physics experiment, we offer them a project close to their daily life: measuring the effect of air resistance on a bicycle. Experiments are done with a bicycle freewheeling on a downhill slope. The data are compared with equations of motions corresponding to different models…
Infiuence of Bicycle Traffic on Capacity of Typical Signalized Intersection
CHEN Xiaoming; SHAO Chunfu; YUE Hao
2007-01-01
Bicycle traffic has a significant effect on the capacity of signalized intersections. This paper divides the influence of bicyclists on vehicular flow into four types with the time durations estimated based on probability, shock wave, and gap acceptance theory. Vehicular saturation flow rate is predicted for various conditions on the basis of the speed-flow curve for the capacity of typical intersections influenced by bicycle traffic.The model overcomes the limitations of the Highway Capacity Manual (HCM, 2000) method for left-turns due to data collection, and takes into account the effect of trapped bicycles on the through vehicular traffic.The numerical results show that the left-turn and through capacities predicted by the model are lower than those of the HCM method. The right-turn capacity is close to that of the HCM method at Iow bicycle volumes and higher than that of the HCM method at high bicycle volumes.
Will a bicycle friendly policy make passenger travel more sustainably?
Christensen, Linda; Jensen, Thomas Christian
The purpose of this paper is to analyse the possibility to transfer a larger part of the short car trips to walking or bicycling in order to obtain environmental and health benefits. The project contains a logistic choice model used to explain which circumstances are particularly important for...... choosing walking and bicycling, and how very different instruments can promote walking and bicycling at the expense of short car trips. Furthermore, the paper describes the most important factors when choosing between bicycling and walking and car driving, respectively, in case of trips of up to 22 km...... and bicycling. The study shows that instruments that improve the cyclists’ speed and increase the car drivers’ time consumption and costs will influence the competition conditions significantly. The total transfer potential will be between 12 and 16 % of the car trips in case of short tours...
Bicyclic Peptide Inhibitor of Urokinase-Type Plasminogen Activator
Roodbeen, Renée; Paaske, Berit; Jiang, Longguang;
2013-01-01
The development of protease inhibitors for pharmacological intervention has taken a new turn with the use of peptidebased inhibitors. Here, we report the rational design of bicyclic peptide inhibitors of the serine protease urokinase-type plasminogen activator (uPA), based on the established...... monocyclic peptide, upain-2. It was successfully converted to a bicyclic peptide, without loss of inhibitory properties. The aim was to produce a peptide cyclised by an amide bond with an additional stabilising across-the-ring covalent bond. We expected this bicyclic peptide to exhibit a lower entropic...... burden upon binding. Two bicyclic peptides were synthesised with affinities similar to that of upain-2, and their binding energetics were evaluated by isothermal titration calorimetry. Indeed, compared to upain-2, the bicyclic peptides showed reduced loss of entropy upon binding to uPA. We also...
Survey of how staff commute to work
2014-01-01
A survey was initiated by the Canton of Geneva (Direction Générale des Transports) and the Swiss Permanent Mission to the United Nations, and is aimed at better understanding how staff in International Organisations commute to/from work so as to better plan future works (road access, public transport, etc.). The ILO, WHO, UNAIDs, Global Fund, IFRC, CERN and UNOG are taking part in this important survey. People living in Switzerland or France are invited to respond to this survey. The purpose of this survey is to better understand: - your commuting habits, - your willingness to explore alternative commuting options, - your expectations and needs. All data provided to this external company (www.mobilidee.ch) will be kept confidential and will only be used for this particular study. CERN has received all guarantees of confidentiality from this company. Many thanks for your collaboration! GS Department
Commutative algebra constructive methods finite projective modules
Lombardi, Henri
2015-01-01
Translated from the popular French edition, this book offers a detailed introduction to various basic concepts, methods, principles, and results of commutative algebra. It takes a constructive viewpoint in commutative algebra and studies algorithmic approaches alongside several abstract classical theories. Indeed, it revisits these traditional topics with a new and simplifying manner, making the subject both accessible and innovative. The algorithmic aspects of such naturally abstract topics as Galois theory, Dedekind rings, Prüfer rings, finitely generated projective modules, dimension theory of commutative rings, and others in the current treatise, are all analysed in the spirit of the great developers of constructive algebra in the nineteenth century. This updated and revised edition contains over 350 well-arranged exercises, together with their helpful hints for solution. A basic knowledge of linear algebra, group theory, elementary number theory as well as the fundamentals of ring and module theory is r...
Beating the traffic with commuting alternatives
NONE
1995-05-01
This pamphlet describes how, by encouraging commuting options, local governments can help reduce air pollution, fuel consumption, and traffic congestion. Minimizing these problems makes the community more appealing to businesses, residents, and visitors and boosts the local economy. Approaches to alternative transportation are as varied as the communities devising and using them. But the critical factor is initiative from local governments, often one of communities largest employers. They can use and promote commuting alternatives among their employees. Local governments can also promote alternative transportation among other employers and the general public. They can provide information on commuting options, improve the infrastructure, and use local authority to require and reward those changes necessary to make alternative transportation a widely accepted part of community life. Best of all, local governments can lead by example and establish a template for other employers to follow.
Structural design of a composite bicycle fork
Highlights: • Case study about composite bicycle fork design. • Special requirements for a Student Team project. • FE model to evaluate stiffness, strength and potential failure modes. • Comparison of two manufacturing approaches. • FE model stiffness validation on the manufactured fork. - Abstract: Despite the wide literature on the mechanical behaviour of carbon/epoxy composites, it is rare to find practical methodological approaches in finite element design of structural components made by laminate layup. Through the case study of a special bicycle fork needed in a Student Team prototype, this paper proposes a simplified methodology as starting point for educational and manufacturing purposes. In order to compare two manufacturing solutions in terms of stiffness, strength and failure mode, a numerical model was implemented. Since the project requirements imposed to avoid standard destructive testing, the model validation was based on a posteriori linear stiffness comparison with the manufactured component. The slight discrepancies between experimental and numerical results were discussed in order to check their origin and to assess the reliability of the model. The overall methodology, even if complain with only a part of the safety standard requirements, shows to be reliable enough and can be the basis for further extension and refinement
The Design of Sport Bicycle Speed Odometer
Dongbing Liu
2013-04-01
Full Text Available As bicycle sport equipment, a sport bike needs a speed and distance measuring device, due to the characteristic of road cycling, thereby mastering the state of motion. According to external conditions such as temperature, wind speed, the bike can make the appropriate adjustment to achieve the best movement effect. The bicycle speed odometer is a major accessibility tool that satisfies with needs of the people with fast development. This study elaborated a bike speed odometer design based on Hall element, taking AT89C52 single chip as the core, measuring speed with A44E Hall sensor, to finish the bike mileage/speed measurement and statistics by displaying bike mileage and speed in real time. By using the Hall elements, the hardware of speed odometer input the number of pulse of per circle into the single-chip computer system. Then the signal processed by the single-chip computer displays. The software is programmed with assembly language and modular design idea. The design of the hardware circuit is simple and the subroutine has universal property, which fully meet the design requirements and possess a wide range of application and dissemination value.
Noncommutative Grobner Bases for Almost Commutative Algebras
Li, Huishi
2007-01-01
Let $K$ be an infinite field and $K =K$ the free associative algebra generated by $X=\\{X_1,...,X_n\\}$ over $K$. It is proved that if $I$ is a two-sided ideal of $K$ such that the $K$-algebra $A=K /I$ is almost commutative in the sense of [3], namely, with respect to its standard $\\mathbb{N}$-filtration $FA$, the associated $\\mathbb{N}$-graded algebra $G(A)$ is commutative, then $I$ is generated by a finite Gr\\"obner basis. Therefor, every quotient algebra of the enve...
Two Approaches to Non-Commutative Geometry
Kisil, V V
1997-01-01
Looking to the history of mathematics one could find out two outer approaches to Geometry. First one (algebraic) is due to Descartes and second one (group-theoretic)--to Klein. We will see that they are not rivalling but are tied (by Galois). We also examine their modern life as philosophies of non-commutative geometry. Connections between different objects (see keywords) are discussed. Keywords: Heisenberg group, Weyl commutation relation, Manin plain, quantum groups, SL(2, R), Hardy space, Bergman space, Segal-Bargmann space, Szeg"o projection, Bergman projection, Clifford analysis, Moebius transformations, functional calculus, Weyl calculus (quantization), Berezin quantization, Wick ordering, quantum mechanics.
A somewhat gentle introduction to differential graded commutative algebra
Beck, Kristen A.; Sather-Wagstaff, Sean
2013-01-01
Differential graded (DG) commutative algebra provides powerful techniques for proving theorems about modules over commutative rings. These notes are a somewhat colloquial introduction to these techniques. In order to provide some motivation for commutative algebraists who are wondering about the benefits of learning and using these techniques, we present them in the context of a recent result of Nasseh and Sather-Wagstaff. These notes were used for the course "Differential Graded Commutative ...
A reconstruction theorem for almost-commutative spectral triples
Ćaćić, Branimir
2012-01-01
We propose an expansion of the definition of almost-commutative spectral triple that accommodates non-trivial fibrations and is stable under inner fluctuation of the metric, and then prove a reconstruction theorem for almost-commutative spectral triples under this definition as a simple consequence of Connes's reconstruction theorem for commutative spectral triples. Along the way, we weaken the orientability hypothesis in the reconstruction theorem for commutative spectral triples, and follow...
On strongly clean matrices over commutative clean rings
Burgess, Walter
2014-01-01
The literature about strongly clean matrices over commutative rings is quite extensive. The sharpest results are about matrices over commutative local rings, for example those by Borooah, Diesl and Dorsey. The purpose of this note is to show that, using Pierce sheaf techniques, many of the known results about matrices over commutative local rings can be extended to those over commutative clean rings in general.
Kraemer, John D; Roffenbender, Jason S; Anderko, Laura
2012-08-01
Bicycle-sharing programs are increasingly popular and have the potential to increase physical activity and decrease air pollution, but anecdotal evidence suggests helmet use is lower among users of bicycle-sharing programs than cyclists on private bicycles. We conducted a cross-sectional study to assess helmet use among users of a bicycle-sharing program in Washington, DC. Helmet use was significantly lower among cyclists on shared bicycles than private bicycles, highlighting a need for targeted helmet promotion activities. PMID:22698021
Roffenbender, Jason S.; Anderko, Laura
2012-01-01
Bicycle-sharing programs are increasingly popular and have the potential to increase physical activity and decrease air pollution, but anecdotal evidence suggests helmet use is lower among users of bicycle-sharing programs than cyclists on private bicycles. We conducted a cross-sectional study to assess helmet use among users of a bicycle-sharing program in Washington, DC. Helmet use was significantly lower among cyclists on shared bicycles than private bicycles, highlighting a need for targeted helmet promotion activities. PMID:22698021
Non-Commutative Formal Groups In Positive Characterstic
Leitner, Frederick
2006-01-01
We describe geometric non-commutative formal groups in terms of a geometric commutative formal group with a Poisson structure on its splay algebra. We describe certain natural properties of such Poisson structures and show that any such Poisson structure gives rise to a non-commutative formal group.
The maximal commutative subalgebra of a Leavitt path algebra
Canto, Cristóbal Gil; Nasr-Isfahani, Alireza
2015-01-01
For any unital commutative ring $R$ and for a graph $E$, we identify a maximal commutative subalgebra of the Leavitt path algebra of $E$ with coefficients in $R$. Besides we are able to characterize injectivity of representations which gives a generalization of Cuntz-Krieger uniqueness theorem, and by other hand, to generalize and simplify the result about commutative Leavitt path algebras over fields.
Improving bicycle safety: The role of paediatricians and family physicians.
Leblanc, John C; Huybers, Sherry
2004-05-01
Cycling is a complex activity requiring motor, sensory and cognitive skills that develop at different rates from childhood to adolescence. While children can successfully ride a two-wheeled bicycle at age five or six, judgment of road hazards are poor at that age and matures slowly until adult-like judgment is reached in early adolescence. Safe cycling depends on the care, skills and judgment of cyclists and motorists; roadway design that promotes safe coexistence of bicycles and motor vehicles; and the use of safety devices, including bicycle helmets, lights and reflective tape. Whereas, research into optimal roadway design and educational programs for drivers to improve road safety has yielded contradictory results, the benefits of bicycle helmet use and programs to enhance their use have been clearly shown. This paper has the following objectives for paediatricians and family physicians: To understand the relationship between bicycle safety and children's motor and cognitive skills.To understand the effectiveness and limitations of strategies to improve bicycle safety.To describe activities to promote bicycle safety that physicians can undertake in clinical settings and in the community. PMID:19657515
Young tableaux and homotopy commutative algebras
Dubois-Violette, Michel; Popov, Todor
2012-01-01
A homotopy commutative algebra, or $C_{\\infty}$-algebra, is defined via the Tornike Kadeishvili homotopy transfer theorem on the vector space generated by the set of Young tableaux with self-conjugated Young diagrams. We prove that this $C_{\\infty}$-algebra is generated in degree 1 by the binary and the ternary operations.
First steps in brave new commutative algebra
Greenlees, J. P. C.
2006-01-01
This is an expository account of completion and local cohomology in brave new commutative algebra, especially as it applies to completion theorems and their duals in equivariant topology. The first part is fairly direct, but the second considers Morita theory and Gorenstein ring spectra. This draws on work of the author with Benson, Dwyer, Iyengar and May, amongst others.
Poincare duality and commutative differential graded algebras
Lambrechts, Pascal; Stanley, Don
2007-01-01
We prove that every commutative differential graded algebra whose cohomology is a simply-connected Poincare duality algebra is quasi-isomorphic to one whose underlying algebra is simply-connected and satisfies Poincare duality in the same dimension. This has application in particular to the study of CDGA models of configuration spaces on a closed manifold.
Algebra cohomology over a commutative algebra revisited
Pirashvili, Teimuraz
2003-01-01
The aim of this paper is to give a relatively easy bicomplex which computes the Shukla, or Quillen cohomology in the category of associative algebras over a commutative algebra $A$, in the case when $A$ is an algebra over a field.
Special functions and q-commuting variables
Koornwinder, Tom H.
1996-01-01
This paper is mostly a survey, with a few new results. The first part deals with functional equations for q-exponentials, q-binomials and q-logarithms in q-commuting variables and more generally under q-Heisenberg relations. The second part discusses translation invariance of Jackson integrals, q-Fourier transforms and the braided line.
(non)commutative f-un geometry
Bruyn, Lieven Le
2009-01-01
Stressing the role of dual coalgebras, we modify the definition of affine schemes over the 'field with one element'. This clarifies the appearance of Habiro-type rings in the commutative case, and, allows a natural noncommutative generalization, the study of representations of discrete groups and their profinite completions being our main motivation.
Non-commutative Sylvester's determinantal identity
Konvalinka, Matjaz
2007-01-01
Sylvester's identity is a classical determinantal identity with a straightforward linear algebra proof. We present a new, combinatorial proof of the identity, prove several non-commutative versions, and find a $\\beta$-extension that is both a generalization of Sylvester's identity and the $\\beta$-extension of the MacMahon master theorem.
The telescope conjecture for semihereditary commutative rings
Bazzoni, Silvana
2013-01-01
The paper has been withdrawn, since there is a mistake in Proposition 5.2. The result on the telescope conjecture for semihereditary rings is correct, but the characterization of the smashing subcategories of the derived category of commutative rings is not complete.
Non-commutative arithmetic circuits with division
Hrubeš, Pavel; Wigderson, A.
2015-01-01
Roč. 11, Article 14 (2015), s. 357-393. ISSN 1557-2862 EU Projects: European Commission(XE) 339691 - FEALORA Institutional support: RVO:67985840 Keywords : arithmetic circuits * non-commutative rational function * skew field Subject RIV: BA - General Mathematics http://theoryofcomputing.org/articles/v011a014/
Z-polynomials and ring commutativity
Buckley, S.M.; McHale, D.
2012-01-01
We characterise polynomials f with integer coefficients such that a ring with unity R is necessarily commutative if f(x) is central for all x Ɛ R. We also solve the corresponding problem without the assumption that the ring has a unity.
Minimal Varieties of Representable Commutative Residuated Lattices
Horčík, Rostislav
2012-01-01
Roč. 100, č. 6 (2012), s. 1063-1078. ISSN 0039-3215 R&D Projects: GA ČR GAP202/10/1826 Institutional research plan: CEZ:AV0Z10300504 Keywords : commutative residuated lattice * subvariety lattice * minimal variety * substructural logic * maximally consistent logic Subject RIV: BA - General Mathematics Impact factor: 0.342, year: 2012
Commutative monads as a theory of distributions
Kock, Anders
2012-01-01
It is shown how the theory of commutative monads provides an axiomatic framework for several aspects of distribution theory in a broad sense, including probability distributions, physical extensive quantities, and Schwartz distributions of compact support. Among the particular aspects considered...... here are the notions of convolution, density, expectation, and conditional probability....
Anomalous commutator corrections to sum rules
In this paper we consider the contributions of anomalous commutators to various QCD sum rules. Using a combination of the Bjorken-Johnson-Low limit with the operator product expansion the results are presented in terms of the vacuum condensates of gauge-invariant operators. It is demonstrated that the anomalous contributions are non-negligible and reconcile various apparently contradictory calculations
Non-commutative arithmetic circuits with division
Hrubeš, Pavel; Wigderson, A.
2015-01-01
Roč. 11, Article 14 (2015), s. 357-393. ISSN 1557-2862 EU Projects: European Commission(XE) 339691 - FEALORA Institutional support: RVO:67985840 Keywords : arithmetic circuits * non-commutative rational function * skew field Subject RIV: BA - General Mathematics http://theoryofcomputing.org/ articles /v011a014/
Hermiticity of quantum observables versus commutation relations
In order to obtain sum rules and spectral representations the Hermiticity property = of observables is used. It is shown that for certain Ψ and Φ the property turn out to be inconsistent with the commutation relations that contain Α. The known Schwinger paradox is explained by this inconsistency
A Cohomology Theory for Commutative Monoids
María Calvo-Cervera
2015-10-01
Full Text Available Extending Eilenberg–Mac Lane’s cohomology of abelian groups, a cohomology theory is introduced for commutative monoids. The cohomology groups in this theory agree with the pre-existing ones by Grillet in low dimensions, but they differ beyond dimension two. A natural interpretation is given for the three-cohomology classes in terms of braided monoidal groupoids.
Spin in the path integral: anti-commuting versus commuting variables
Scholtz, F. G.; Theron, A. N.; Geyer, H. B.
1994-01-01
We discuss the equivalence between the path integral representations of spin dynamics for anti-commuting (Grassmann) and commuting variables and establish a bosonization dictionary for both generators of spin and single fermion operators. The content of this construction in terms of the representations of the spin algebra is discussed in the path integral setting. Finally it is shown how a `free field realization' (Dyson mapping) can be constructed in the path integral.
The frequency of single-bicycle crashes (SBCs) in countries with varying bicycle mode shares
Schepers, Paul; Agerholm, Niels; Amoros, Emmanuelle;
In order to encourage cycling, we need to reduce the hazards that cyclists face. Single-bicycle crashes or ‘bicycle-only crashes’ are falls and obstacle collisions in which only one cyclist is involved. Between 60 and 95% of cyclists admitted to hospital or treated at an emergency...... department are victims of single-bicycle crashes. As proportion of the total number of traffic casualties the share exceeds 20% in most countries with medium to high levels of cycling. This paper discusses the prevalence of the problem and describes measures that may both reduce the...
Use and activity levels on newly built bicycle playgrounds
Schipperijn, Jasper; Hansen, Christine Kier; Rask, Simon
2015-01-01
Increasing the use of urban green space (UGS) as well as increasing cycling could potentially help address the growing inactivity problem. Three bicycle playgrounds were designed based on a participatory process and afterwards constructed in the UGS along a cycle-route on the historic outer defence...... close to one of the sites. A future study involving objective before and after measures when a new bicycle playground is build will be needed to reveal if bicycle playgrounds can provide additional activity to its users, or ‘just’ a different type of activity, in a different location....
Efficiency of choice set generation methods for bicycle routes
Halldórsdóttir, Katrín; Rieser-Schussler, Nadine; Axhausen, Kay W.;
2014-01-01
The current study analyses the efficiency of choice set generation methods for bicycle routes and proposes the extension of cost functions to bicycle-oriented factors not limited to distance and time. Three choice set generation methods for route choice were examined in their ability to generate...... scenic routes, dedicated cycle lanes, and road type. Data consisted of 778 bicycle trips traced by GPS and carried out by 139 persons living in the Greater Copenhagen Area, in Denmark. Results suggest that both the breadth first search on link elimination and the doubly stochastic generation function...
Symbolic derivation of bicycle kinematics with toroidal wheels
Wang Everett X.
2015-01-01
Full Text Available Bicycle kinematics with toroidal wheels is presented in this paper. Using symbolic mathematic tool Maple, we obtain two holonomic and four nonholonomic constraint equations due to front and rear wheels of a bicycle. We show that the two holonomic constraints cannot be expressed in quartic form for bicycle rear body pitch angle unless the minor (crown radius of the torus are the same for both the front and rear wheels. In addition, we show that all the constraints can be written in differential form, from which a constraint matrix is constructed, according to standard procedure for developing dynamics in robotics.
Bamboo Bicycle – Past or Future?
Suzana Jakovljević
2016-01-01
Full Text Available In this article the experiment was carried out to establish tensile strength values of two different bamboo species, which are obtained by the static tensile test. The tensile strength results of two tested species Tonkin Cane and Ku Zhu bamboo are presented and compared with traditional materials used for bicycle frame to determine their suitability for designing a frame. Physiology and other properties of bamboo were elaborated as well. The purpose of this study was to gain more knowledge on bamboo and prove his suitability in use as an alternative for ecologically unacceptable materials. Therefore, application of the natural materials is essential for the sustainable development. The fact that they have unlimited resources the use of bamboo has great potential and this article explains why.
Bicyclic graphs with maximal revised Szeged index
Li, Xueliang
2011-01-01
The revised Szeged index $Sz^*(G)$ is defined as $Sz^*(G)=\\sum_{e=uv \\in E}(n_u(e)+ n_0(e)/2)(n_v(e)+ n_0(e)/2),$ where $n_u(e)$ and $n_v(e)$ are, respectively, the number of vertices of $G$ lying closer to vertex $u$ than to vertex $v$ and the number of vertices of $G$ lying closer to vertex $v$ than to vertex $u$, and $n_0(e)$ is the number of vertices equidistant to $u$ and $v$. Hansen used the AutoGraphiX and made the following conjecture about the revised Szeged index for a connected bicyclic graph $G$ of order $n \\geq 6$:
Bicycling induced pudendal nerve pressure neuropathy.
Silbert, P L; Dunne, J W; Edis, R H; Stewart-Wynne, E G
1991-01-01
Pudendal neuropathies are well recognised as part of more generalised peripheral neuropathies; however, focal abnormalities of the pudendal nerve due to cycling-related injuries have been infrequently reported. We describe two patients who developed pudendal neuropathies secondary to pressure effects on the perineum from racing-bicycle saddles. Both were male competitive athletes, one of whom developed recurrent numbness of the penis and scrotum after prolonged cycling; the other developed numbness of the penis, an altered sensation of ejaculation, with disturbance of micturition and reduced awareness of defecation. Both patients improved with alterations in saddle position and riding techniques. We conclude that pudendal nerve pressure neuropathy can result from prolonged cycling, particularly when using a poor riding technique. PMID:1821826
The effect of tyre and rider properties on the stability of a bicycle
Bulsink, V.E.; Doria, A.; Belt, van de, M.; Koopman, H.F.J.M.
2015-01-01
To work towards an advanced model of the bicycle-rider-environment system, an open-loop bicycle-rider model was developed in the commercial multibody dynamics software ADAMS. The main contribution of this article to bicycle dynamics is the analysis of tyre and rider properties that influence bicycle stability. A system identification method is used to extract linear stability properties from time domain analysis. The weave and capsize eigenmodes of the bicycle-rider system are analysed. The e...
Exploring characteristics and motives of long distance commuter cyclists
Hansen, Karsten Bruun; Sick Nielsen, Thomas
2014-01-01
, commuter cyclists (45 km from home to work) have more mobility options, higher incomes, and a longer education than other commuter cyclists. The main motive for longer distance cycling is physical exercise, followed by reduced costs and time used for traveling. The long distance commuter cyclists surveyed......Longer distance cycling is a commuting mode that contributes to sustainability and public health objectives, but little is known about current long distance cyclist's motives. The paper explores longer distance commuter cyclists, their characteristics, practice and motives. Longer distance...
Schepers, Paul; Agerholm, Niels; Amoros, Emmanuelle; Benington, Rob; Bjørnskau, Torkel; Dhondt, Stijn; de Geus, Bas; Hagemeister, Carmen; Loo, Becky P. Y.; Niska, Anna
2015-01-01
Objectives To study cyclists’ share of transport modes (modal share) and single-bicycle crashes (SBCs) in different countries in order to investigate if the proportion of cyclist injuries resulting from SBCs is affected by variation in modal share. Methods A literature search identified figures...... SBC casualties among the total number of road crash casualties increases proportionally less than the increase in bicycle modal share. Conclusions While most fatal injuries among cyclists are due to motor vehicle–bicycle crashes, most hospital admissions and emergency department attendances result...
Fluid Mechanics of a High Performance Racing Bicycle Wheel
Mercat, Jean-Pierre; Cretoux, Brieuc; Huat, Francois-Xavier; Nordey, Benoit; Renaud, Maxime; Noca, Flavio
2013-11-01
In 2012, MAVIC released the most aerodynamic bicycle wheel on the market, the CXR 80. The french company MAVIC has been a world leader for many decades in the manufacturing of bicycle wheels for competitive events such as the Olympic Games and the Tour de France. Since 2010, MAVIC has been in a research partnership with the University of Applied Sciences in Geneva, Switzerland, for the aerodynamic development of bicycle wheels. While most of the development up to date has been performed in a classical wind tunnel, recent work has been conducted in an unusual setting, a hydrodynamic towing tank, in order to achieve low levels of turbulence and facilitate quantitative flow visualization (PIV). After a short introduction on the aerodynamics of bicycle wheels, preliminary fluid mechanics results based on this novel setup will be presented.
Associations between bicycling and carotid arterial stiffness in adolescents
Ried-Larsen, M; Grøntved, A; Østergaard, Lars;
2015-01-01
The aim of the study was to investigate the associations between bicycling and carotid arterial stiffness, independent of objectively measured moderate-and-vigorous physical activity. This cross-sectional study included 375 adolescents (age 15.7 ± 0.4 years) from the Danish site of the European...... Youth Heart Study. Total frequency of bicycle usage was assessed by self-report, and carotid arterial stiffness was assessed using B-mode ultrasound. After adjusting for pubertal status, body height, and objectively measured physical activity and other personal lifestyle and demographic factors, boys...... using their bicycle every day of the week displayed a higher carotid arterial compliance {standard beta 0.47 [95% confidence interval (CI) 0.07-0.87]} and distension [standard beta 0.38 (95% CI -0.04 to 0.81)]. Boys using their bicycle every day of the week furthermore displayed a lower Young's elastic...
The safety impact of a yellow bicycle jacket
Lahrmann, Harry; Madsen, Tanja Kidholm Osmann
2016-01-01
The hypothesis of this project is that the safety of cyclists can be improved by increasing their visibility in traffic. This is explored by testing whether or not a high-visibility bicycle jacket (colour and reflectors) will increase the safety of cyclists. The project has been carried out as a...... randomized controlled trial with 6,800 volunteer cyclists. After random selection, half of the group – the test group – got the bicycle jacket at once and promised to wear it each time they biked during a year. The other half of the group composed a control group that got the bicycle jacket after the closing...... of the project, i.e. after a year. The safety effect of the bicycle jacket was analysed by comparing the number of self-reported accident for the test and control group. The self-reported accidents showed that the test group had 38 % fewer personal injury accidents with other road users – so...
Interventions in Bicycle Infrastructure, Lessons from Dutch and Danish Cases
van Goeverden, K.; Nielsen, Thomas Alexander Sick; Harder, Henrik;
2015-01-01
evident. At the time, in both countries large scale interventions in bicycle infrastructure were introduced and evaluated extensively in order to create knowledge on efficient promoting of cycling in urban areas. The interventions included the construction of new bicycle routes on urban arterials in some...... larger cities and an area wide comprehensive upgrade of the bicycle network one medium sized city (Delft). The evaluations were based on before and after studies where in the case of Delft also a long-term after study was performed. The evaluations produced a wealth of information about the impacts of...... interventions in bicycle infrastructure on travel choices, safety, design appreciation, and other factors. These clarify under which conditions certain measures are effective or not and inform about the effectiveness of improving a single route versus upgrading a whole network. The information from the studies...
Vehicle exhaust is a major source of air pollution in metropolitan cities. Commuters are exposed to high traffic-related pollutant concentrations. Public transportation is the most popular commuting mode in Hong Kong and there are about 10.8 million passenger trips every day. Two-thirds of them are road commuters. An extensive survey was conducted to measure carbon monoxide in three popular passenger commuting modes, bus, minibus, and taxi, which served, respectively, 3.91 million, 1.76 million and 1.31 million passenger trips per day in 1998. Three types of commuting microenvironments were selected: urban-urban, urban-suburban and urban-rural. Results indicated that in-vehicle CO level increased in the following order: bus, minibus and taxi. The overall average in-vehicle CO level in air-conditioned bus, minibus and taxi were 1.8, 2.9 and 3.3ppm, respectively. The average concentration level between air-conditioned buses (1.8ppm) and non-air-conditioned buses (1.9ppm) was insignificant. The fluctuation of in-vehicle CO level of non-air-conditioned vehicle followed the variation of out-vehicle CO concentration. Our result also showed that even in air-conditioned vehicles, the in-vehicle CO concentration was affected by the out-vehicle CO concentration although there exists a smoothing out effect. The in-vehicle CO level was the highest in urban-suburban commuting routes and was followed by urban-urban routes. The in-vehicle CO level in urban-rural routes was the lowest. The highest CO level was recorded after the vehicle traversed through tunnel.. The average CO exposure level of public road transportation commuters in Honk Kong was lower than most other cities. Factors governing the CO levels were also discussed. (Author)
Improving bicycle safety: The role of paediatricians and family physicians
LeBlanc, John C.; Huybers, Sherry
2004-01-01
Cycling is a complex activity requiring motor, sensory and cognitive skills that develop at different rates from childhood to adolescence. While children can successfully ride a two-wheeled bicycle at age five or six, judgment of road hazards are poor at that age and matures slowly until adult-like judgment is reached in early adolescence. Safe cycling depends on the care, skills and judgment of cyclists and motorists; roadway design that promotes safe coexistence of bicycles and motor vehicl...
Modeling the Distribution Characteristics of Urban Public Bicycle Rental Duration
Shuichao Zhang; Kangkang He; Sheng Dong; Jibiao Zhou
2016-01-01
In order to model the distribution characteristics of public bicycle rental durations, individual journey data for three cities in China (Ningbo, Hangzhou, and Beijing), for weekdays, was obtained. The distribution curves for public bicycle rental duration in the three cities were found to be extremely similar, with small differences among the weekdays. The basic parameters such as the average rental duration, the rental duration corresponding to the maximum rental frequency, and the rental d...
BICYCLE TRANSPORT IN URBAN TRANSPORT OF KONYA CITY
LORASOKKAY, Mehmet Ali; AĞIRDIR, M. Levent
2011-01-01
The use of motor vehicles in the cities of Turkey is increasing with every passing day due to the cities rapidly expanding in Turkey. The share of environment-friendly transportation types entirely based on manpower such as pedestrian and bicycle transports in urban areas continuously decreases due to expanding urban residential areas. For urban transportation, bicycle is an individual, independent and fast transportation vehicle similar to motor vehicles in terms of its properties such as it...
On the Skill of Balancing While Riding a Bicycle.
Cain, Stephen M; Ashton-Miller, James A; Perkins, Noel C
2016-01-01
Humans have ridden bicycles for over 200 years, yet there are no continuous measures of how skill differs between novice and expert. To address this knowledge gap, we measured the dynamics of human bicycle riding in 14 subjects, half of whom were skilled and half were novice. Each subject rode an instrumented bicycle on training rollers at speeds ranging from 1 to 7 m/s. Steer angle and rate, steer torque, bicycle speed, and bicycle roll angle and rate were measured and steering power calculated. A force platform beneath the roller assembly measured the net force and moment that the bicycle, rider and rollers exerted on the floor, enabling calculations of the lateral positions of the system centers of mass and pressure. Balance performance was quantified by cross-correlating the lateral positions of the centers of mass and pressure. The results show that all riders exhibited similar balance performance at the slowest speed. However at higher speeds, the skilled riders achieved superior balance performance by employing more rider lean control (quantified by cross-correlating rider lean angle and bicycle roll angle) and less steer control (quantified by cross-correlating steer rate and bicycle roll rate) than did novice riders. Skilled riders also used smaller steering control input with less variation (measured by average positive steering power and standard deviations of steer angle and rate) and less rider lean angle variation (measured by the standard deviation of the rider lean angle) independent of speed. We conclude that the reduction in balance control input by skilled riders is not due to reduced balance demands but rather to more effective use of lean control to guide the center of mass via center of pressure movements. PMID:26910774
On the Skill of Balancing While Riding a Bicycle.
Stephen M Cain
Full Text Available Humans have ridden bicycles for over 200 years, yet there are no continuous measures of how skill differs between novice and expert. To address this knowledge gap, we measured the dynamics of human bicycle riding in 14 subjects, half of whom were skilled and half were novice. Each subject rode an instrumented bicycle on training rollers at speeds ranging from 1 to 7 m/s. Steer angle and rate, steer torque, bicycle speed, and bicycle roll angle and rate were measured and steering power calculated. A force platform beneath the roller assembly measured the net force and moment that the bicycle, rider and rollers exerted on the floor, enabling calculations of the lateral positions of the system centers of mass and pressure. Balance performance was quantified by cross-correlating the lateral positions of the centers of mass and pressure. The results show that all riders exhibited similar balance performance at the slowest speed. However at higher speeds, the skilled riders achieved superior balance performance by employing more rider lean control (quantified by cross-correlating rider lean angle and bicycle roll angle and less steer control (quantified by cross-correlating steer rate and bicycle roll rate than did novice riders. Skilled riders also used smaller steering control input with less variation (measured by average positive steering power and standard deviations of steer angle and rate and less rider lean angle variation (measured by the standard deviation of the rider lean angle independent of speed. We conclude that the reduction in balance control input by skilled riders is not due to reduced balance demands but rather to more effective use of lean control to guide the center of mass via center of pressure movements.
Test verification and design of the bicycle frame parameters
Zhang, Long; Xiang, Zhongxia; Luo, Huan; Tian, Guan
2015-07-01
Research on design of bicycles is concentrated on mechanism and auto appearance design, however few on matches between the bike and the rider. Since unreasonable human-bike relationship leads to both riders' worn-out joints and muscle injuries, the design of bicycles should focus on the matching. In order to find the best position of human-bike system, simulation experiments on riding comfort under different riding postures are done with the lifemode software employed to facilitate the cycling process as well as to obtain the best position and the size function of it. With BP neural network and GA, analyzing simulation data, conducting regression analysis of parameters on different heights and bike frames, the equation of best position of human-bike system is gained at last. In addition, after selecting testers, customized bikes based on testers' height dimensions are produced according to the size function. By analyzing and comparing the experimental data that are collected from testers when riding common bicycles and customized bicycles, it is concluded that customized bicycles are four times even six times as comfortable as common ones. The equation of best position of human-bike system is applied to improve bikes' function, and the new direction on future design of bicycle frame parameters is presented.
Bicycle helmet use and non-use - recently published research.
Uibel, Stefanie; Müller, Daniel; Klingelhoefer, Doris; Groneberg, David A
2012-01-01
Bicycle traumata are very common and especially neurologic complications lead to disability and death in all stages of the life. This review assembles the most recent findings concerning research in the field of bicycle traumata combined with the factor of bicycle helmet use. The area of bicycle trauma research is by nature multidisciplinary and relevant not only for physicians but also for experts with educational, engineering, judicial, rehabilitative or public health functions. Due to this plurality of global publications and special subjects, short time reviews help to detect recent research directions and provide also information from neighbour disciplines for researchers. It can be stated that to date, that although a huge amount of research has been conducted in this area more studies are needed to evaluate and improve special conditions and needs in different regions, ages, nationalities and to create successful prevention programs of severe head and face injuries while cycling.Focus was explicit the bicycle helmet use, wherefore sledding, ski and snowboard studies were excluded and only one study concerning electric bicycles remained due to similar motion structures within this review. The considered studies were all published between January 2010 and August 2011 and were identified via the online databases Medline PubMed and ISI Web of Science. PMID:22632628
Schepers, Paul; Agerholm, Niels; Amoros, Emmanuelle;
2015-01-01
Objectives To study cyclists’ share of transport modes (modal share) and single-bicycle crashes (SBCs) in different countries in order to investigate if the proportion of cyclist injuries resulting from SBCs is affected by variation in modal share. Methods A literature search identified figures...... (largely from western countries) on SBC casualties who are fatally injured, hospitalised or treated at an emergency department. Correlation and regression analyses were used to investigate how bicycle modal share is related to SBCs. Results On average, 17% of fatal injuries to cyclists are caused by SBCs...... SBC casualties among the total number of road crash casualties increases proportionally less than the increase in bicycle modal share. Conclusions While most fatal injuries among cyclists are due to motor vehicle–bicycle crashes, most hospital admissions and emergency department attendances result...
Domazet, Sidsel L; Tarp, Jakob; Huang, Tao;
2016-01-01
OBJECTIVES: To examine objectively measured physical activity level, organized sports participation and active commuting to school in relation to mathematic performance and inhibitory control in adolescents. METHODS: The design was cross-sectional. A convenient sample of 869 sixth and seventh grade...... students (12-14 years) was invited to participate in the study. A total of 568 students fulfilled the inclusion criteria and comprised the final sample for this study. Mathematic performance was assessed by a customized test and inhibitory control was assessed by a modified Eriksen flanker task. Physical...... level was stratified by bicycling status in order to bypass measurement error subject to the accelerometer. RESULTS: Non-cyclists in the 2nd quartile of counts per minute displayed a higher mathematic score, so did cyclists in the 2nd and 3rd quartile of moderate-to-vigorous physical activity relative...