An analysis of short haul air passenger demand, volume 2

Several demand models for short haul air travel are proposed and calibrated on pooled data. The models are designed to predict demand and analyze some of the motivating phenomena behind demand generation. In particular, an attempt is made to include the effects of competing modes and of alternate destinations. The results support three conclusions: (1) the auto mode is the air mode's major competitor; (2) trip time is an overriding factor in intermodal competition, with air fare at its present level appearing unimportant to the typical short haul air traveler; and (3) distance appears to underly several demand generating phenomena, and therefore, must be considered very carefully to any intercity demand model. It may be the cause of the wide range of fare elasticities reported by researchers over the past 15 years. A behavioral demand model is proposed and calibrated. It combines the travel generating effects of income and population, the effects of modal split, the sensitivity of travel to price and time, and the effect of alternative destinations satisfying the trip purpose

Absolute calibration of the LOPES antenna system

Radio emission in extensive air showers arises from an interaction with the geomagnetic field and is subject of theoretical studies. This radio emission has advantages for the detection of high energy cosmic rays compared to secondary particle or fluorescence measurement methods. Radio antennas like the LOPES30 antenna system are suited to investigate this emission process by detecting the radio pulses. The characteristic observable parameters like electric field strength and pulse length require a calibration which was done with a reference radio source resulting in an amplification factor representing the system behavior in the environment of the KASCADE-Grande experiment. Knowing the amplification factor and the gain of the LOPES antennas LOPES30 is calibrated absolutely for systematic analyses of the radio emission.Comment: 5 pages, Proceedings of International Workshop on Acoustic and Radio EeV Neutrino detection Activities: ARENA, May 17-19, 2005, DESY Zeuthe

Single-qubit unitary gates by graph scattering

We consider the effects of plane-wave states scattering off finite graphs, as an approach to implementing single-qubit unitary operations within the continuous-time quantum walk framework of universal quantum computation. Four semi-infinite tails are attached at arbitrary points of a given graph, representing the input and output registers of a single qubit. For a range of momentum eigenstates, we enumerate all of the graphs with up to $n=9$ vertices for which the scattering implements a single-qubit gate. As $n$ increases, the number of new unitary operations increases exponentially, and for $n>6$ the majority correspond to rotations about axes distributed roughly uniformly across the Bloch sphere. Rotations by both rational and irrational multiples of $\pi$ are found.Comment: 8 pages, 7 figure

Understandig the Role of Scenarios in Swiss Energy Research

Energy scenarios link long-term policy goals to near-term decisions and may thus guide the transition to more sustainable energy systems. Yet, systematic empirical analyses of how energy scenarios are understood and used by relevant actors are rare. This working paper addresses the situation in Switzerland, where several competing public energy scenarios have been developed by different organisations in reaction to the government’s decision to phase out nuclear power. The analysis focuses on the energy research community, which has a double role in the dissemination of scenario-based insights: On the one hand, researchers develop energy scenarios which may in turn be used by decision-makers in policy and industry to create or assess action alternatives. On the other hand, many researchers are scenario users themselves. We conducted 13 structured in-depth interviews with energy researchers. The sample covers a wide scope of institutions and disciplinary backgrounds, including economics, engineering, geography, sociology, and law. We find that while most researchers do use energy scenarios, there are, essentially, two contrasting types of scenario use among them: One group of researchers, which we labelled divers, is interested in very specific data and assumptions that it wants to fully understand. A second group, which we labelled sailors, refers to the results of a scenario analysis in a more general manner. We identified different interpretations of scenario content between sailors and divers. These discrepancies are a result of the highly specialised modelling activities on which energy scenarios are based. Implicit knowledge that is generated during the process of developing energy sce-narios is inaccessible to most scenarios users. We therefore conclude the study with a discussion about the usefulness of participative stakeholder involvement and scenario documentation that is adjusted to the interests and competencies of its users. Because energy scenarios increasingly serve as a scientifically derived information basis for societal debates about energy transitions, their use needs to be studied more extensively

Course-based Science Research Promotes Learning in Diverse Students at Diverse Institutions

Course-based research experiences (CREs) are powerful strategies for spreading learning and improving persistence for all students, both science majors and nonscience majors. Here we address the crucial components of CREs (context, discovery, ownership, iteration, communication, presentation) found across a broad range of such courses at a variety of academic institutions. We also address how the design of a CRE should vary according to the background of student participants; no single CRE format is perfect. We provide a framework for implementing CREs across multiple institutional types and several disciplines throughout the typical four years of undergraduate work, designed to a variety of student backgrounds. Our experiences implementing CREs also provide guidance on overcoming barriers to their implementation

Composite repetition-aware data structures

In highly repetitive strings, like collections of genomes from the same species, distinct measures of repetition all grow sublinearly in the length of the text, and indexes targeted to such strings typically depend only on one of these measures. We describe two data structures whose size depends on multiple measures of repetition at once, and that provide competitive tradeoffs between the time for counting and reporting all the exact occurrences of a pattern, and the space taken by the structure. The key component of our constructions is the run-length encoded BWT (RLBWT), which takes space proportional to the number of BWT runs: rather than augmenting RLBWT with suffix array samples, we combine it with data structures from LZ77 indexes, which take space proportional to the number of LZ77 factors, and with the compact directed acyclic word graph (CDAWG), which takes space proportional to the number of extensions of maximal repeats. The combination of CDAWG and RLBWT enables also a new representation of the suffix tree, whose size depends again on the number of extensions of maximal repeats, and that is powerful enough to support matching statistics and constant-space traversal.Comment: (the name of the third co-author was inadvertently omitted from previous version

A computer simulation of Tampa International Airport's landside terminal and shuttles

Cover titleApril 1976TOPSIM, a terminal simulation package developed at M.I.T., was used to simulate Tampa's landside terminal and to study its capacity-congestion characteristics as traffic levels increase. Tampa has no congestion problems at present, processing 5 million passengers per year, but may in the future. TOPSIM indicates that congestion arises at the ticket counters and on the critical segments of the elevator cycle when annual traffic volumes reach 14+ million passengers. TOPSIM's modular design has sufficient flexibility to handle a variety of airport layouts without major reprogramming effort. The package was previously used to simulate passenger flows for hypothetical "Metroport" terminals (handling passenger volumes similar to LaGuardia) and for Eastern Airlines' terminal at Logan. It produces performance statistics on passenger movements (such as total distance walked and time spent standing in queues), and on facilities (such as utilization of ticket booths). TOPSIM's application to Tampa demonstrates its ability to handle other than "shuttle" oriented terminals. In fact, it can theoretically simulate any terminal regardless of trip type or mode, since the passenger processing routine is similar for most terminals

The purpose of mess in action research: building rigour though a messy turn

Mess and rigour might appear to be strange bedfellows. This paper argues that the purpose of mess is to facilitate a turn towards new constructions of knowing that lead to transformation in practice (an action turn). Engaging in action research - research that can disturb both individual and communally held notions of knowledge for practice - will be messy. Investigations into the 'messy area', the interface between the known and the nearly known, between knowledge in use and tacit knowledge as yet to be useful, reveal the 'messy area' as a vital element for seeing, disrupting, analysing, learning, knowing and changing. It is the place where long-held views shaped by professional knowledge, practical judgement, experience and intuition are seen through other lenses. It is here that reframing takes place and new knowing, which has both theoretical and practical significance, arises: a 'messy turn' takes place

From risk to vulnerability : the role of perceived adaptive capacity for the acceptance of contested infrastructure

Infrastructure projects such as repositories for nuclear waste or hazardous waste sites impose risks (in the form of potential burdens or losses) over extensive timescales. These risks change dynamically over time and so, potentially, does their management. Societies and key actors go through learning processes and subsequently may be better able to deal with related challenges. However, social scientific research on the acceptance of such projects is mainly concerned with (static) risk perception issues and does not include dynamic aspects. Adaptive capacity, which is part of the concept of vulnerability, therefore represents a promising complementing facet for this line of research. The aim of this paper is to examine the role of perceived adaptive capacity for the acceptance of contested long-term infrastructure for the two issues of nuclear and hazardous waste. In an online experimental survey (N = 300) examining either the acceptance of a nuclear waste repository or of a hazardous waste site we demonstrate that i) perceived adaptive capacity can be separated empirically as a psychological construct from risk and benefit perception, and ii) perceived adaptive capacity explains a significant additional share of variance in the acceptance of both waste types beyond risk and benefit perception. Furthermore, we report what adaptation mechanisms of perceived adaptive capacity participants expect to occur in the future. We conclude that such a dynamic perspective yields important insights in understanding individual decision-making regarding long-term infrastructure projects