Performance calculations of rocket tri-propellant systems.

This thesis document was issued under the authority of another institution, not NPS. At the time it was written, a copy was added to the NPS Library collection for reasons not now known.  It has been included in the digital archive for its historical value to NPS.  Not believed to be a CIVINS (Civilian Institutions) title.http://www.archive.org/details/performancecalcu00simsU.S. Navy (U.S.N.) author

Duality Theory And the Consistent Estimation Of Technological Parameters: Why Cost Function Estimation Can Be Wrong

In this article we show that technological parameter estimates obtained by estimating a cost function that is derivable as the dual of a production function can be biased and inconsistent if the stochastic structure of the model arises from certain types of behavioural assumptions made about rational agents. We consider a specific example in which firms are uncertain about prices. We show that when actual prices differ from expected prices and firms have to make decisions on the basis of their expectations, the inherited stochastic specification of the dual system is highly non-linear in the disturbance terms making consistent parameter estimation impossible by conventional methods. This is demonstrated by a Monte Carlo simulation study of two text-book examples using synthetic data. It is also shown that this type of result can arise when the researcher derives the error structure from the assumption that agents make optimization errors.cost functions; duality; estimation

PHYSIOLOGICAL FACTORS REGULATING APPETITE IN THE LESSER SPOTTED DOGFISH SHARK, SCYLIORHINUS CANICULA (L.)

Some aspects of digestive and systemic function were investigated in relation to their role in the peripheral regulation of appetite in juvenile and adult, S. canicula. This study represents the first evaluation of the physiological factors that contribute to the control of shark appetite. Daily food intake trials on both juvenile and adult dogfish showed repeatable, self-regulated feeding rhythms indicating the existence of an endogenous component to food intake control. After dogfish consumed satiation meals of 7% wet body weight (wbw) the appetite return increased at constant rates as deprivation time increased. The relative rate of food processing was 50% faster in juveniles than adults. The pattern of gastric emptying of squid diet was exponential and dependent on the degree of stomach fullness, with meals of different size being emptied at different relative rates. It was also shown that dogfish were capable of shunting undigested food into the intestine soon after consumption of large meals. There was inverse proportionality between rate of gastric evacuation and appetite return rate indicating the importance of the physiological perception of relative stomach emptiness in the establishment of appetite. Gastric emptying rates were not influenced by changes in the digestible energy level of the diet, which suggests this shark exhibits a predominantly bulk dependent feeding pattern. Increases in post-prandial metabolism or specific dynamic action (SDA) did not seemingly alter the rate of appetite return in dogfish, though SDA and appetite return were shown to be closely linked metabolic processes. The SDA process in dogfish may have a saturation level determined by cellular metabolism rather than by the respiratory system. The levels of plasma glucose remained uniform after food consumption. The concentrations of triglycerides and protein in plasma were closely controlled post-prandially, suggesting a possible role for these metabolites as systemic signals of metabolic satiety. The results of this investigation are discussed with regard to the multifactorial control of appetite in sharks and the possible use of physiological studies of appetite in the further understanding of fish feeding strategies.Marine Biological Association of the United Kingdo

Effects of extrinsic rewards and social comparison on inhibitory control in adults with ADHD symptoms.

The current study was an attempt to understand the links between reward processes, upward social comparisons, and behavioral inhibition in adults with ADHD and ADHD symptoms. Studies have shown that motivation can improve inhibitory control in children with ADHD, but little has been done to show the same effect in adults with ADHD. Additionally, social rewards such as praise and positive feedback have been shown to improve inhibitory control in children with ADHD, though not as strongly as tangible rewards. The current study used monetary rewards as well as false information regarding the performance of other participants to elicit an upwards social comparison. Monetary rewards had the greatest effect on the speed of inhibitory control in the ADHD group. Social comparison did not significantly improve the speed of response inhibition in the ADHD group, and in fact seemed to hurt accuracy. On the other hand, it did improve the speed of response inhibition for the non-ADHD control group. Neither monetary rewards nor the social comparison manipulation significantly affected the accuracy of the participants. Overall, the ADHD and control groups performed similarly. Future research needs to examine any differences that may exist in how individuals with ADHD symptoms use social comparison information when compared to their non-ADHD counterparts

High Data Rates for AubieSat-2 A & B, Two CubeSats Performing High Energy Science in the Upper Atmosphere

This paper will discuss a proposed CubeSat size (3 Units / 6 Units) telemetry system concept being developed at Marshall Space Flight Center (MSFC) in cooperation with Auburn University. The telemetry system incorporates efficient, high-bandwidth communications by developing flight-ready, low-cost, PROTOFLIGHT software defined radio (SDR) payload for use on CubeSats. The current telemetry system is slightly larger in dimension of footprint than required to fit within a 0.75 Unit CubeSat volume. Extensible and modular communications for CubeSat technologies will provide high data rates for science experiments performed by two CubeSats flying in formation in Low Earth Orbit. The project is a collaboration between the University of Alabama in Huntsville and Auburn University to study high energy phenomena in the upper atmosphere. Higher bandwidth capacity will enable high-volume, low error-rate data transfer to and from the CubeSats, while also providing additional bandwidth and error correction margin to accommodate more complex encryption algorithms and higher user volume

Tactically Extensible and Modular Communications X-Band TEMCOM-X

This paper will discuss a CubeSat size (3U) telemetry system concept being developed at Marshall Space Flight Center (MSFC) in cooperation with the U.S. Department of the Army and Dynetics Corporation. This telemetry system incorporates efficient, high-bandwidth communications by developing flight-ready, low-cost, Proto-flight software defined radio (SDR) and Electronically Steerable Patch Array (ESPA) antenna subsystems for use on platforms as small as CubeSats and unmanned aircraft systems (UASs). Higher bandwidth capacity will enable high-volume, low error-rate data transfer to and from tactical forces or sensors operating in austere locations (e.g., direct imagery download, unattended ground sensor data exfiltration, interlink communications)

Flip Paths Between Lattice Triangulations

Diagonal flip paths between triangulations have been studied in the combinatorial setting for nearly a century. One application of flip paths to Euclidean distance geometry and Moebius geometry is a recent, simple, constructive proof by Connelly and Gortler of the Koebe-Andreev-Thurston circle packing theorem that relies on the existence of a flip path between any two triangulation graphs. More generally, length and other structural quantities on minimum (length) flip paths are metrics on the space of triangulations. In the geometric setting, finding a minimum flip path between two triangulations is NP-complete. However, for two lattice triangulations, used to model electron spin systems, Eppstein and Caputo et al. gave algorithms running in $O\left(n^2\right)$ time, where $n$ is the number of points in the point-set. Their algorithms apply to constrained flip paths that ensure a set of \emph{constraint} edges are present in every triangulation along the path. We reformulate the problem and provide an algorithm that runs in $O\left(n^{\frac{3}{2}}\right)$ time. In fact, for a large, natural class of inputs, the bound is tight, i.e., our algorithm runs in time linear in the length of this output flip path. Our results rely on structural elucidation of minimum flip paths. Specifically, for any two lattice triangulations, we use Farey sequences to construct a partially-ordered sets of flips, called a minimum flip \emph{plan}, whose linear-orderings are minimum flip paths between them. To prove this, we characterize a minimum flip plan that starts from an equilateral lattice triangulation - i.e., a lattice triangulation whose edges are all unit-length - and \emph{forces a point-pair to become an edge}. To the best of our knowledge, our results are the first to exploit Farey sequences for elucidating the structure of flip paths between lattice triangulations.Comment: 24 pages (33 with appendices), 8 figure

Software Defined Radios - Architectures, Systems and Functions

Software Defined Radio is an industry term describing a method of utilizing a minimum amount of Radio Frequency (RF)/analog electronics before digitization takes place. Upon digitization all other functions are performed in software/firmware. There are as many different types of SDRs as there are data systems. Software Defined Radio (SDR) technology has been proven in the commercial sector since the early 90's. Today's rapid advancement in mobile telephone reliability and power management capabilities exemplifies the effectiveness of the SDR technology for the modern communications market. In contrast the foundations of transponder technology presently qualified for satellite applications were developed during the early space program of the 1960's. SDR technology offers potential to revolutionize satellite transponder technology by increasing science data through-put capability by at least an order of magnitude. While the SDR is adaptive in nature and is "One-size-fits-all" by design, conventional transponders are built to a specific platform and must be redesigned for every new bus. The SDR uses a minimum amount of analog/Radio Frequency components to up/down-convert the RF signal to/from a digital format. Once analog data is digitized, all processing is performed using hardware logic. Typical SDR processes include; filtering, modulation, up/down converting and demodulation. This presentation will show how the emerging SDR market has leveraged the existing commercial sector to provide a path to a radiation tolerant SDR transponder. These innovations will reduce the cost of transceivers, a decrease in power requirements and a commensurate reduction in volume. A second pay-off is the increased flexibility of the SDR by allowing the same hardware to implement multiple transponder types by altering hardware logic - no change of analog hardware is required - all of which can be ultimately accomplished in orbit. This in turn would provide high capability and low cost transponder to programs of all sizes