1,721,157 research outputs found
An Approach to the Study of Money and Nonmoney Exchange Structures
No full textWallace, Neil. (1971). An Approach to the Study of Money and Nonmoney Exchange Structures. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/54247
The Stability of Models of Money and Growth with Perfect Foresight
No full textSargent, Thomas J.; Wallace, Neil. (1972). The Stability of Models of Money and Growth with Perfect Foresight. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/54327
Rational Expectations and the Dynamics of Hyperinflation
No full textSargent, Thomas J.; Wallace, Neil. (1972). Rational Expectations and the Dynamics of Hyperinflation. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/54631
Identification and Estimation of a Model of Hyperinflation with a Continuum of "Sunspot" Equilibria
No full textThis paper constructs a model with two structural equations: the government
budget constraint and a linear version of Cagan's portfolio balance equation.
the model contains a continuum of equilibria with "sunspot equilibria." Closed
forms for the solutions are found. Even though there is a continuum of equilibria,
the model is overidentified econometrically, so that the model restricts
time series data on price levels and currency stocks. We describe how the free
parameters of the model can be estimated, including some parameters that serve
to index particular members of the continuum of equilibria. The sunspot equilibria
hold out some promise of explaining anomalies in the observed behavior of
inflation and real balances during hyperinflations.Sargent, Thomas J.; Wallace, Neil. (1985). Identification and Estimation of a Model of Hyperinflation with a Continuum of "Sunspot" Equilibria. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/55489
European Student Moon Orbiter solar electric propulsion subsystem architecture: an all–electric spacecraft
No full textThis paper presents the Phase A study of the Solar Electric Propulsion subsystem selected for the ESA European Student Moon Orbiter enhanced microsatellite, performed at QinetiQ under ESA funding. To minimise mass, a so-called "all electric" approach is adopted based around the re-use of the GOCE T5 gridded ion engine and the introduction of Hollow Cathode Thrusters (HCTs) for attitude control functions. Three different subsystem architectures are considered and analyzed with reference to the mass, cost, risk and level of integration between the HCTs and the T5. The favoured system architecture that best meets the various requirements adopts a shared tank and gas flow controller between the HCTs and the T5, with power being supplied from two dedicated power processing units. The possibility of reducing the propellant requirement by using an engine gimbal mechanism is also presented. The study also demonstrates how an increase in the T5 specific impulse to higher values than used on GOCE does not offer substantial system-level mass savings in this particular case
Emitter depletion measurement and modeling in the T5&T6 Kaufman-type ion thrusters
No full textThis paper presents some of the aspects of a program undertaken by Qineti Q to characterize and determine the depletion rates and predict life time of its cathode technology. It reports on a long duration test performed on the T5 (15,000 hours) and a series of shorter tests on the T6 (800hours and 4000hours) including the results of destructive post test examinations and insert depletion measurements. The program also includes a modeling of insert depletion by Southampton University which has currently produced good agreement with measured depletion on the 15,000 hour T5 insert. Two tests have also been carried out on the T6 cathode to determine an end of life condition. An accelerated lifetest where the insert temperature was increased by 20oC has to date accumulated 3790 hours of operation. This is equivalent to 30,320hours with an 8×acceleration factor or 60,640hours assuming a 16× acceleration factor. Another test was also undertaken with two grossly depleted T6 inserts (25% and 50% depleted). Both cathodes although grossly depleted still behaved nominally. All the results give a degree of confidence in the compatibility of the T6 thruster cathode with future high impulse mission lifetime requirements
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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