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UC Berkeley transportation seminar series

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  • asha.weinstein@sjsu.edu
    UC Berkeley s Institute of Transportation Studies organizes a series of talks on transportation each Friday at 4 p.m., during the academic year. While some of
    Message 1 of 1 , Feb 17, 2003
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      UC Berkeley's Institute of Transportation Studies organizes a series of
      talks on transportation each Friday at 4 p.m., during the academic year.
      While some of the talks are quite technical (oriented to an engineering
      audience), others are of interest to planners. You can find the schedule
      at:

      http://www.ce.berkeley.edu/Programs/Transportation/Transoc/TransSem_SP03

      Below you will also find abstract for some of the talks coming up. I
      particularly recommend the one on e-commerce by Patricia Mokhtarian, a
      professor at UC Davis.

      Asha


      Asha Weinstein
      Department of Urban and Regional Planning
      San José State University
      One Washington Square
      San Jose, CA 95192-0185
      email: asha.weinstein@...
      phone: 408-924-5853

      __________

      February 21, 2003
      David Levinson
      How Networks Grow
      First the research empirically examines the growth of a highway network
      based on the present and historical conditions of the network, traffic
      demand, demographic characteristics, project costs, and budget. The
      effects of expanding a link on its upstream and downstream neighbors, as
      well as on parallel links are also considered. Results show that high
      capacity links are less likely to be expanded and a higher budget results
      in more links being expanded, supporting the underlying economic theory.
      Increasing usage of a highway has a significant effect on the expansion
      corroborating the induced supply hypothesis. Second we explore the
      question more abstractly, modeling the dynamics of the orientation of
      major roads in a network to understand the basic properties of
      transportation networks. Localized investment rules ?revenue produced by
      traffic on a link is invested for that link? own development ?are
      employed. Under reasonable parameters, these investment rules, coupled
      with traveler behavior, and underlying network topology result in the
      emergence of a hierarchical pattern. Hypothetical networks subject to
      certain conditions are tested with this model to explore the network
      properties. Though hierarchies seem to be designed by planners and
      engineers, the results show that they are intrinsic properties of
      networks. Also, the results show that roads, specific routes with
      continuous attributes, are emergent properties of transportation networks.

      February 28, 2003
      Patricia L. Mokhtarian
      A Conceptual Analysis of The Transportation Impacts of B2c E-Commerce
      This paper discusses, at a conceptual level, a number of issues related
      to the evaluation of the transportation and spatial impacts of
      e-shopping. We review the comparative advantages of store shopping and
      e-shopping, and conclude that neither type uniformly dominates the other.
      We identify the building blocks of the shopping process, and note that
      information and communications technologies are making possible the
      spatial and temporal fragmentation and recombination of those elements. We
      analyze future shopping-related changes in transportation as the net
      outcome of four different fundamental causes that can be viewed
      hierarchically:
      (1) changes in shopping mode share (i.e. shifts in the proportion of
      shopping activities conducted through store shopping, e-shopping and other
      modes), keeping the volume of goods purchased and per capita consumption
      spending constant;
      (2) changes in the volume of goods purchased, keeping per capita
      consumption spending constant;
      (3) changes in per capita consumption spending, independent of demographic
      changes; and
      (4) demographic changes.
      Some factors result in reduced travel while others lead to increased
      travel. The combined outcome of all factors does not appear to support
      any hope that e-shopping will reduce travel on net; to the contrary there
      may be negative impacts due to increased travel, even if those impacts are
      likely to be localized and/or small in magnitude for the most part. Thus,
      on the whole, we are likely (with some exceptions) to see continued
      adoption of both store shopping and e-shopping. Consumers will blend both
      forms as they conduct a sequence of shopping activities, and retailers
      will blend both in marketing to and serving customers. Assessing the
      transportation impacts of e-shopping even in the short term, let alone
      the long term presents some formidable measurement challenges.
      Nevertheless, those challenges are worthy of our most creative efforts at
      solution.

      March 14, 2003
      Frank S. Koppelman
      Advances in Discrete Choice Modeling
      Random utility maximization discrete choice models are widely used in
      transportation and other fields to represent the choice of one among a set
      of mutually exclusive alternatives. The decision maker, in each case, is
      assumed to choose the alternative with the highest utility to him/her. The
      utility to the decision maker of each alternative is not completely known
      by the modeler; thus, the modeler represents the utility by a
      deterministic portion which is a function of the attributes of the
      alternative and the characteristics of the decision-maker and an additive
      random component which represents unknown and/or unobservable components
      of the decision maker's utility function.
      Early development of choice models was based on the assumption that the
      error terms were multivariate normal or independently and identically Type
      I extreme value (gumbel) distributed. The multivariate normal assumption
      leads to the multinomial probit (MNP) model; the independent and identical
      gumbel assumption leads to the multinomial logit (MNL) model. The probit
      model allows complete flexibility in the variance-covariance structure of
      the error terms but estimation and application requires numerical
      integration of a multi-dimensional normal distribution. The multinomial
      logit probabilities can be evaluated directly but the assumption that the
      error terms are independently and identically distributed across
      alternatives and cases (individuals, households or choice repetitions)
      places important limitations on the competitive relationships among the
      alternatives. Developments in the structure of discrete choice models have
      been directed at either reducing the computational burden associated with
      the multinomial probit model or increasing the flexibility of extreme
      value models. Development of the Mixed Logit Model (XML) combines the
      advantages of logit and probit models while limiting the degree of
      computational complexity associated with the probit model.
      March 21, 2003
      Diego Klabjan
      Due to the flight disruptions in operations, the crew scheduling cost at
      the end of a month is substantially higher than the projected cost in
      planning. We present a model that yields more robust crew schedules in
      planning. Besides the objective of minimizing the cost, we introduce the
      objective of maximizing the number of crew that can be swapping in
      operations. We present a solution methodology for solving the resulting
      model. The produced crew schedules are evaluated with a simulation.
      Several possible extensions and directions will be discussed.

      April 4, 2003
      Geoffrey D. Gosling

      The Global Aviation Information Network (GAIN) is an international
      industry/government partnership established to promote and facilitate the
      voluntary collection and sharing of safety information by and among users
      in the international aviation community to improve safety. The seminar
      will discuss recent trends in international aviation safety, the challenge
      facing efforts to further improve aviation safety, and the importance of
      sharing safety information in these efforts. The presentation will then
      describe the organizational structure of the GAIN program, including the
      activities of the various working groups and their recent products, and
      the role of research in support of the GAIN program undertaken by the
      National Center of Excellence for Aviation Operations Research over the
      past six years. The presentation will conclude by describing some of the
      findings of recent site visits to airline flight safety departments to
      identify and document the state of the art in the collection and analysis
      of flight safety data, including the capabilities of various analytical
      tools in use by different airlines, and suggest opportunities for future
      research to improve the capabilities of these tools.
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