12,551 research outputs found
Performance, physiological, and oculometer evaluation of VTOL landing displays
A methodological approach to measuring workload was investigated for evaluation of new concepts in VTOL aircraft displays. Physiological, visual response, and conventional flight performance measures were recorded for landing approaches performed in the NASA Visual Motion Simulator (VMS). Three displays (two computer graphic and a conventional flight director), three crosswind amplitudes, and two motion base conditions (fixed vs. moving base) were tested in a factorial design. Multivariate discriminant functions were formed from flight performance and/or visual response variables. The flight performance variable discriminant showed maximum differentation between crosswind conditions. The visual response measure discriminant maximized differences between fixed vs. motion base conditions and experimental displays. Physiological variables were used to attempt to predict the discriminant function values for each subject/condition trial. The weights of the physiological variables in these equations showed agreement with previous studies. High muscle tension, light but irregular breathing patterns, and higher heart rate with low amplitude all produced higher scores on this scale and thus represent higher workload levels
ON THE FACILITATIVE ROLE OF THE ECONOMIST IN ECONOMIC DEVELOPMENT - CASE STUDY OF A GEORGIA SHRIMP HARBOR INVESTMENT
Community/Rural/Urban Development,
Energy-balance climate models
An introductory survey of the global energy balance climate models is presented with an emphasis on analytical results. A sequence of increasingly complicated models involving ice cap and radiative feedback processes are solved and the solutions and parameter sensitivities are studied. The model parameterizations are examined critically in light of many current uncertainties. A simple seasonal model is used to study the effects of changes in orbital elements on the temperature field. A linear stability theorem and a complete nonlinear stability analysis for the models are developed. Analytical solutions are also obtained for the linearized models driven by stochastic forcing elements. In this context the relation between natural fluctuation statistics and climate sensitivity is stressed
Early assessment of the UK innovation investment fund
The UK Innovation Investment Fund (UKIIF), announced by the UK Government in June 2009, is a venture capital fund of funds that aims to drive economic growth and create highly skilled jobs by investing in innovative businesses where there are significant growth opportunities. The UKIIF attempts to mark a step change in the UK venture capital (VC) market by establishing a substantial fund of funds that will replicate the best US funds by making investments at all business stages, with the market scale that can build companies with global reach. The underlying funds within the UKIIF fund of funds will invest in technology based businesses in strategically important sectors to the UK including digital technologies, life sciences1, clean technology2 and advanced manufacturing.
This research provides an early assessment of the lessons learned in implementing and delivering the UKIIF ahead of the main evaluation and provides early indications of the extent to which it is addressing market failures in the UK VC market and contributing to business growth
The effect of a scanning flat fold mirror on a CMB B-mode experiment
We investigate the possibility of using a flat-fold beam steering mirror for
a CMB B-mode experiment. An aluminium flat-fold mirror is found to add
0.075% polarization, which varies in a scan synchronous way. Time-domain
simulations of a realistic scanning pattern are performed, and the effect on
the power-spectrum illustrated and a possible method of correction applied.Comment: 8 pages, 5 figures. Accepted for publication in Rev Sci Ins
Assessment of different urban traffic control strategy impacts on vehicle emissions
This paper investigates the influence of traffic signal control strategy on vehicle emissions, vehicle journey time and total throughput flow within a single isolated four-armed junction. Two pre-timed signal plans are considered, one with two-stages involving permissive-only opposing turns and the other with four-stages which has no conflicting traffic. Additionally, the increase in efficiency by utilising actuated signal timing where green time is re-optimised as flow values vary is investigated. A microscopic traffic simulation model is used to model flows and AIRE (Analysis of Instantaneous Road Emissions) microscopic emissions model is utilised to out- put emission levels from the flow data. A simple junction model shows that the two-stage signal plan is more efficient in both emis- sions and journey time. However, as the level of opposed turning vehicles and conflicting movement increases, the two-stage model moves to being the inferior signal plan choice and the four-stage plan outputs fewer emissions than the two-stage plan. A real-world example of a four-armed junction has been used in this study and from the traffic survey data and existing junction layout; it is rec- ommended that a two-stage plan is used as it produces lower amounts of emissions and shorter journey times compared to a four-stage plan. The results also show that nitrogen oxides (NOx) are the most sensitive to changes in flow followed by carbon dioxide (CO2), Black Carbon and then particulate matter (PM10)
Geographic analysis of multiple sensor data from the NASA/USGS earth resources program
Qualitative and quantitative analyses were made of multi-sensor data acquired during aircraft missions. While the principal analysis effort was concentrated on imagery taken over test sites in Southern California, data were also studied from records acquired on missions over test sites at Phoenix, Chicago, Asheville, and New Orleans. The objectives of the analyses were: (1) to determine the capabilities of ten remote sensors in identifying the elements of information necessary in conducting geographic investigations in land use analysis, urban problems, surface energy budget, and soil moisture; (2) to determine the feasibility of using these sensors for these purposes at orbital altitudes; and (3) to collate and analyze ground and air data previously collected and assemble it in a format useful in the accomplishment of cost effectiveness studies
Empirical constraints on vacuum decay in the stringy landscape
It is generally considered as self evident that the lifetime of our vacuum in
the landscape of string theory cannot be much shorter than the current age of
the universe. Here I show why this lower limit is invalid. A certain type of
``parallel universes'' is a necessary consequence of the string-landscape
dynamics and might well allow us to ``survive'' vacuum decay. As a consequence
our stringy vacuum's lifetime is empirically unconstrained and could be very
short. Based on this counter-intuitive insight I propose a novel type of
laboratory experiment that searches for an apparent violation of the
quantum-mechanical Born rule by gravitational effects on vacuum decay. If the
lifetime of our vacuum should turn out to be shorter than 6 x 10^{-13} seconds
such an experiment is sufficiently sensitive to determine its value with
state-of-the-art equipment.Comment: 13 pages, 2 figures, proposes a laboratory experimen
Ecology of Thysanoptera within Cabbage Fields
The occurrence and species composition of thrips within cabbage fields were studied during 1981 and 1982. Temporal differences in abundance and species composition depended on the spatial relationship of cabbage fields to cereal and forage crops. Sticky traps within cabbage fields recorded peak flights of thrips during maturation and senescence of adjacent wheat or oat fields and cutting of adjacent alfalfa and red clover fields. These data indicate several important findings regarding the ecology of thrips in general and the possible management of Thrips tabaci Lindeman in particular. First, although there are large numbers of thrips in cabbage fields during certain time periods (e.g., maturation or harvesting of crops), most will not be T. tabaci and need not be of concern to cabbage growers. Second, there are significant differences in thrips phenology and species composition in cabbage fields, and these differences appear to be dependent on phenology and management of adjacent field and forage crops. Third, although many other species are present, T. tabaci appears to be present in adequate numbers to infest cabbage at the critical period of head formation. This critical period occurs at different times depending on area, planting date, variety, and weathe
Overwintering of the Onion Thrips, Thrips tabaci (Thysanoptera: Thripidae), in New York
A survey of overwintering thrips and the potential for Thrips tabaci Lindeman to overwinter in upstate New York were investigated during the winters of 1982-83 and 1983-84. Six species—T. tabaci, Anaphothrips obscurus (Müller), Chirothrips manicatus Haliday, Limothrips denticornis (Haliday), Frankltniella tenuicornis (Uzel), and Aptinothrips rufus (Gmelin)—were able to survive as adults in the vegetation sampled, but only Anaphothripini survived as larvae. T. tabaci adults overwinter within winter wheat, alfalfa, and weedy vegetation, and these overwintering females are capable of ovipositing on these plants during the spring. Winter wheat, oats, and alfalfa were the best oviposition and reproduction hosts we examine
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