9,455 research outputs found
An approach to market analysis for lighter than air transportation of freight
An approach is presented to marketing analysis for lighter than air vehicles in a commercial freight market. After a discussion of key characteristics of supply and demand factors, a three-phase approach to marketing analysis is described. The existing transportation systems are quantitatively defined and possible roles for lighter than air vehicles within this framework are postulated. The marketing analysis views the situation from the perspective of both the shipper and the carrier. A demand for freight service is assumed and the resulting supply characteristics are determined. Then, these supply characteristics are used to establish the demand for competing modes. The process is then iterated to arrive at the market solution
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Outside the Voucher: Evaluating the Creative Voucher Scheme
This chapter seeks to elaborate on what one might have expected to be the straightforward task of delivering and evaluating Creativeworks London’s (CWL) Creative Voucher scheme.1 What made the project difficult was that the notion of the “creative” voucher has not been used before; it was not a policy developed from a direct evidence base. Moreover, the Creativeworks London project was premised on the delivery of three funding streams of which the vouchers were one; indeed something approaching half of these funds were targeted to resource creative vouchers.
This chapter offers a discussion of how we implemented the creative vouchers, the product of which makes up most of this volume. It also raises the question of what and how one might evaluate vouchers; something, we argue, that does not gain from a reduction to a limited set of quantitative indicators. Indeed, our reflections on the process projected us into a far more exploratory and nuanced narrative account of the vouchers; hence the chapters of this book which represent a range of different facets and experiences of the creative voucher scheme.
Traditional evaluations of innovation and knowledge transfer are based upon simplistic mono-causal models whereby the dominant notion is that knowledge will naturally diffuse from high concentrations to low concentrations: like a gas; this of course is a social physics model. The failure to diffuse evenly, it is normally hypothesized, must be due to some “blockage” or “barrier.” In keeping with mechanical analogies, much policy action is focused on “fixing the plumbing” that is the leaky knowledge pipelines. The challenge is that the logic behind knowledge transfer, let alone policies such as vouchers, are seldom explicitly stated, but rather assumed as common sense.
As we experience the transformation from mass production economies to those based on what are variously termed service economies, knowledge economies, or even cultural economies the physical movement of goods, innovation and ideas materialized as “solutions” (as “technology” has commonly been) has been replaced by weightless or virtual goods: ideas. Physicalist analogies might have been helpful in an old manufacturing economy; it is clear that they are less helpful in either dematerialized production, or the realm of ideas exclusively.
Moreover, the Creativeworks London project was explicitly funded by the Arts and Humanities Research Council (AHRC) with a view to demonstrating the role of what the arts and humanities can contribute to the processes of knowledge transfer between universities and the creative economy (see Chapter One). It is obvious that the arts and humanities favor different approaches to knowledge than that of the sciences; in particular the humanities focus on the nature of human experience and ideas—one might argue that it is the ideal type of knowledge transfer. The humanities has a rather more nuanced and relational perspective on knowledge and human experience than the sciences, focused as they often are on physical processes and outcomes. We saw it as our task to explore and reflect on creative vouchers and meanings.
Whereas the individual voucher stories provide a rich narrative of what the knowledge exchange process “looks like” and at times what it might “feel like,” and what meanings it produces for those involved, this chapter attempts to examine a linked story across the voucher process. It is not seeking to generalize or summarize, rather it explores the voucher process. In this sense we resist the traditional notion of evaluation, arguing that it is necessary to understand the process before we can possibly evaluate it against objectives, personal, institutional or political
High-performance thermionic converter Quarterly progress report, 13 Aug. - 13 Nov. 1965
Fabrication and testing of cesium loaded thermionic converter test vehicl
CSI sensing and control: Analytical and experimental results
Recent work on structural identification and large-angle maneuvers with vibration suppression was presented. The recent work has sought to balance structural and controls analysis activities by involving the analysts directly in the validation and experimental aspects of the research. Some new sensing, actuation, system identification, and control concepts were successfully implemented. An overview of these results is given
High-performance thermionic converter Quarterly progress report, 13 Nov. 1965 - 13 Feb. 1966
Stability and optimization parameters of cesium vapor thermionic converters studied in high performance long life equipment fabrication projec
Methodological advances
The study of population dynamics has long depended on methodological progress. Among many striking examples, continuous time models for populations structured in age (Sharpe & Lotka, 1911) were made possible by progress in the mathematics of integral equations. Therefore the relationship between population ecology and mathematical and statistical modelling in the broad sense raises a challenge in interdisciplinary research. After the impetus given in particular by Seber (1982), the regular biennial EURING conferences became a major vehicle to achieve this goal. It is thus not surprising that EURING 2003 included a session entitled "Methodological advances". Even if at risk of heterogeneity in the topics covered and of overlap with other sessions, such a session was a logical way of ensuring that recent and exciting new developments were made available for discussion, further development by biometricians and use by population biologists.
The topics covered included several to which full sessions were devoted at EURING 2000 (Anderson, 2001) such as: individual covariates, Bayesian methods, and multi–state models. Some other topics (heterogeneity models, exploited populations and integrated modelling) had been addressed by contributed talks or posters. Their presence among "methodological advances", as well as in other sessions of EURING 2003, was intended as a response to their rapid development and potential relevance to biological questions. We briefly review all talks here, including those not published in the proceedings.
In the plenary talk, Pradel et al. (in prep.) developed GOF tests for multi–state models. Until recently, the only goodness–of–fit procedures for multistate models were ad hoc, and non optimal, involving use of standard tests for single state models (Lebreton & Pradel, 2002). Pradel et al. (2003) proposed a general approach based in particular on mixtures of multinomial distributions. Pradel et al. (in prep.) showed how to decompose tests into interpretable components as proposed by Pollock et al. (1985) for the Cormack–Jolly–Seber model Pledger et al. (in prep.) went on in their thorough exploration of models with heterogeneity of capture (Pledger & Schwarz, 2002; Pledger et al., 2003), by considering the use of finite mixture models for the robust design. Given the level of details in demographic traits presently addressed by capture–recapture, the problem of heterogeneity, once apparently settled by fairly reassuring messages (Carothers, 1973, 1979), is becoming again a central issue, with potential disastrous consequences if improperly handled.
Heterogeneity models, that bear also a relationship to "multi–event models" (Pradel, in press), will thus certainly be increasingly useful. Pollock, Norris, and Pledger (in prep.) reviewed the capture–recapture models as applied to community data (Boulinier et al., 1998) and developed general removal and capture–recapture models when multiple species are sampled to estimate community parameters. Because of unequal delectability between species, these approaches bear a clear relationship to heterogeneity models, which will be more and more a reference for comparative studies of communities and "macroecology" (Gaston & Blackburn, 2000).
Bonner & Schwarz (2004) proposed a capture–recapture model with continuous individual covariates changing over time more fully developed in Bonner & Schwarz (2004). The difficulty here is to set up a sub–model predicting the covariate value when an individual is not captured. While multi–state models permit an ad hoc treatment by categorizing the covariate, Bonner and Schwarz bring a sound answer by considering the covariate obeys a Markov chain with continuous state–space.
Otis & White (2004) presented a thorough, simulation–based, investigation of two approaches used to test the contrasting hypotheses of additive and compensatory hunting mortality based on band recovery data. The two approaches are the usual ultra–structural model and a new one based on a random effects model. This paper can be viewed as part of a revival of studies of the dynamics of exploited populations, in the broad sense, including the study of man–induced mortality in the framework of conservation biology (Lebreton, in press). This revival is a direct consequence of the increasing impact of man on the biosphere and of continuing methodological progress (Ferson & Burgman, 2000). The use of random effects models (see also Schaub & Lebreton, 2004) directly builds upon the seminal work by Anderson and Burnham (1976).
Stauffer presented a Winbugs implementation of the Cormack–Jolly–Seber model that complemented other presentations in the conference and the short course. Finally, Morgan, Besbeas, Thomas, Buckland, Harwood, Duck and Pomery, proposed a thorough and timely review of integrated modelling, i.e., in our context, of models considering simultaneously capture–recapture demographic information and census information. These methods were covered in other sessions, in relation to Bayesian methodology. Integrated modelling appears indeed to be the logical way of combining all pieces of information arising from integrated monitoring, and as one of the great methodological challenges for our community in the years to come (Besbeas et al., 2002).
Methodological progress in population dynamics is apparently still on an upward trajectory and we look forward to many exciting contributions at future EURING conferences
Dissipation enhanced vibrational sensing in an olfactory molecular switch
Motivated by a proposed olfactory mechanism based on a
vibrationally-activated molecular switch, we study electron transport within a
donor-acceptor pair that is coupled to a vibrational mode and embedded in a
surrounding environment. We derive a polaron master equation with which we
study the dynamics of both the electronic and vibrational degrees of freedom
beyond previously employed semiclassical (Marcus-Jortner) rate analyses. We
show: (i) that in the absence of explicit dissipation of the vibrational mode,
the semiclassical approach is generally unable to capture the dynamics
predicted by our master equation due to both its assumption of one-way
(exponential) electron transfer from donor to acceptor and its neglect of the
spectral details of the environment; (ii) that by additionally allowing strong
dissipation to act on the odorant vibrational mode we can recover exponential
electron transfer, though typically at a rate that differs from that given by
the Marcus-Jortner expression; (iii) that the ability of the molecular switch
to discriminate between the presence and absence of the odorant, and its
sensitivity to the odorant vibrational frequency, are enhanced significantly in
this strong dissipation regime, when compared to the case without mode
dissipation; and (iv) that details of the environment absent from previous
Marcus-Jortner analyses can also dramatically alter the sensitivity of the
molecular switch, in particular allowing its frequency resolution to be
improved. Our results thus demonstrate the constructive role dissipation can
play in facilitating sensitive and selective operation in molecular switch
devices, as well as the inadequacy of semiclassical rate equations in analysing
such behaviour over a wide range of parameters.Comment: 12 pages, 6 figures, close to published version, comments welcom
Mixing ratios of trace gases in the austral polar atmosphere during August and September of 1987
Mixing ratios are presented for a number of long-lived trace gases in the austral polar atmosphere during August and September of 1987. The recent discovery of a 12-year trend of increasing depletion of ozone over the Antarctic Continent in the spring of each year led to numerous theoretical interpretations and several scientific expeditions to the region. The results herein were obtained as part of a major effort involving penetration of the region of ozone depletion by NASA's multi-instrumented aircraft. One of the 14 instruments on the high-altitude ER-2 aircraft collected pressurized air samples between latitudes of 53 degrees and 72 degrees south at pressure altitudes up to 21 km in a series of 12 flights from Punta Arenas, Chile, over the Palmer Peninsula. The sampling system, located in the nose section of ER-2, has an inlet tube in the free airstream, a metal-bellows air pump, and 14 specially treated 1.6 l stainless-steel canisters for containing the pressurized air at 350 kPa. A typical flight profile consisted of a southbound path on the 428 K potential temperature surface, a descent to a pressure altitude of 13.7 km, a climb to the 460 K surface, and return on this surface. Mixing ratios for the trace gases were obtained from gas chromatographic analyses of the pressurized air samples. Of the species measured, the mixing ratios for CH4, CO, N2O, CF2 Cl2, CFCl3, CH3, CCl3, CCl4, and C2F3Cl3 are reported here
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