10,953 research outputs found
Lie algebra and super-affinization of split-octonions
The purpose of this study is to extend the concept of a generalized Lie
algebra, known to the divisional algebra of the octonions , to
split-octonions , which is non-divisional. This is achieved
through the unification of the product of both of the algebras in a single
operation. Accordingly, a notational device is introduced to unify the product
of both algebras. We verify that is a Malcev algebra and we
recalculate known relations for the structure constants in terms of the
introduced structure tensor. Finally we construct the manifestly
super-symmetric affine super-algebra. An
application of the split Lie algebra for a Bagger and Lambert gauge theory
is also discussed.Comment: 17 pages without figure
ENGLISH LANGUAGE FOR SUCCESSFUL INTEGRATION: LEARNING FROM THE BOLOGNA PROCESS
The Bologna Process aims to provide tools to connect the European national educational systems. The purpose of this paper is to analyze what we have learned and what challenges remain today. Since the beginning all participating countries had to agree on a comparable three cycle degree system for undergraduates (Bachelor degrees or Grades) and graduates (Master and PhD degrees) in order to create compatibility and comparability for achieving international competitiveness and a worldwide degree of attractiveness in higher education. The Bologna Declaration, originally signed by 29 countries, has now reached 47 countries, engaged in the process of creating a European Higher Education Area (EHEA), searching to be competitive to launch the European Academia of the 21st Century. The European Credit Transfer and Accumulation System (ECTS) has turned out to be the perfect tool to design, describe, and deliver programs and award higher education qualifications. Markets and European universities are going to be able to compete overseas in the future if the new regulations let them to create profitable business in the education area. As expected, European Universities have responded promptly and actively to the call. In the case of small countries like Spain, it is an opportunity to internationalize Spanish universities; moreover, there is the opportunity for the expansion and consolidation of the Spanish language as the second most important foreign language. The 2009 Report highlights that early teaching of a foreign language is advancing in Europe. In lower secondary education, earlier teaching of English is becoming widespread; and the three Nordic countries, Germany, and the UK are the highest innovation performers. The result is a system of higher education more competitive and more attractive for Europeans and non-Europeans students and scholars. Reform is needed today if Europe wants to match the performance of the best performing higher education systems in the world. The English language seems to be the response in the search for a common European answer to solve common European problems.English, Bologna Process, European Higher Education Area, EHEA, Spanish
Why choose the new I-35W Mississippi River Bridge?
On September 18th 2008, a replacement for the previously collapsed I-35W bridge opened to the public. Consequently, travelers were once again confronted with the opportunity to find better alternatives. The traffic pattern of the Minneapolis road network was likely to readjust, because of the new link addition. However, questions arise about the possible reasons (or components in the route choice process) that are likely to influence travelers crossing the Mississippi, who had to choose among the bridge options, including the new I-35W bridge. Using GPS data and web-based survey collected both before and after the replacement bridge opened, a bridge choice model is estimated using weighted-least squares logit. In this way the proportion of I-35W trips can be estimated depending on the assigned values of the explanatory variables, which include: statistical measures of the travel time distribution experienced by the subjects, alternative diversity, and others. The results showed that travel time savings and reliability were the main reasons for choosing the new I-35W bridge.I-35W Mississippi River Bridge, Route Choice, Route Assignment, Traffic Assignment, Discrete Choice
Value of Travel Time Reliability: A review of current evidence
Travel time reliability is a fundamental factor in travel behavior. It represents the temporal uncertainty experienced by users in their movement between any two nodes in a network. The importance of the time reliability depends on the penalties incurred by the users. In road networks, travelers consider the existence of a trip travel time uncertainty in different choice situations (departure time, route, mode, and others). In this paper, a systematic review of the current state of research in travel time reliability, and more explicitly in the value of travel time reliability is presented. Moreover, a meta-analysis is performed in order to determine the reasons behind the discrepancy among the reliability estimates.variability, reliability, travel time, scheduling.
Value of Reliability: High Occupancy Toll Lanes, General Purpose Lanes, and Arterials
In the Minneapolis-St. Paul region (Twin Cities), the Minnesota Department of Transportation (MnDOT) converted the Interstate 394 High Occupancy Vehicle (HOV) lanes to High Occupancy Toll (HOT) lanes (or MnPASS Express Lanes). These lanes allow single occupancy vehicles (SOV) to access the HOV lanes by paying a fee. This fee is adjusted according to a dynamic pricing system that varies with the current demand. This paper estimates the value placed by the travelers on the HOT lanes because of improvements in travel time reliability. This value depends on how the travelers regard a route with predictable travel times (or small travel time variability) in comparison to another with unpredictable travel times (or high travel time variability). For this purpose, commuters are recruited and equipped with Global Positioning System (GPS) devices and instructed to commute for two weeks on each of three plausible alternatives between their home in the western suburbs of Minneapolis eastbound to work in downtown or the University of Minnesota: I-394 HOT lanes, I-394 General Purpose lanes (untolled), and signalized arterials close to the I-394 corridor. They are then given the opportunity to travel on their preferred route after experiencing each alternative. This revealed preference data is then analyzed using mixed logit route choice models. Three measures of reliability are explored and incorporated in the estimation of the models: standard deviation (a classical measure in the research literature); shortened right range (typically found in departure time choice models); and interquartile range (75th - 25th percentile). Each of these measures represents distinct ways about how travelers deal with different sections of reliability. In all the models, it was found that reliability was valued highly (and statistically significantly), but differently according to how it was defined. The estimated value of reliability in each of the models indicates that commuters are willing to pay a fee for a reliable route depending on how they value their reliability savings.time reliability, GPS, route choice, random utility, I-394 HOT, MnPass, mixed logit
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