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971.
One of the more significant errors in the history of science occurred during the “marginal revolution” in economics near the end of the nineteenth century. Rather than explicitly recognize in basic theory that the happiness we seek to maximize in life originates within oneself, the early theorists formulated their equations as though human satisfaction resided in external things-as in so much utility (economist's term for satisfaction) per pound of sugar. Over the past 125 years, economists have developed mainstream mathematical economics on this incorrect basis resulting in the ill-founded neoclassical Equilibrium Theory. Because of this error economic theory is fundamentally timeless. The present theory, in its canonical form, corrects the early marginalist's error by identifying utility (time-integrated pleasure) exclusively with the stream-of-consciousness attending (expected) mental and physical activity. Time is now explicit in basic theory, thereby allowing, for the first time, the substantive computer-modeling of time-dependent, small- and large-scale economic systems. Furthermore, this new approach is methodologically compatible with mainstream sociology and institutional economics, allowing increased interdisciplinary cooperation that may influence policy and thereby affect industry and markets. And safety engineering stands to benefit from the accommodation of neuropsychology in understanding human error in the supervision and control of technology 相似文献
972.
A possible variant presented for solving the equation of motion of a rotating flow is more general with respect to the variants known in the literature. On the basis of the simultaneous solution of the equations of motion and energy, the temperature fields are determined under changes of the rotation nature. 相似文献
973.
Aeronautical telemetry using multiple-antenna transmitters 总被引:1,自引:0,他引:1
Jensen M.A. Rice M.D. Anderson A.L. 《IEEE transactions on aerospace and electronic systems》2007,43(1):262-272
The placement of multiple antennas on an air vehicle is one possible practice for overcoming signal obstruction created by vehicle maneuvering during air-to-ground transmission. Unfortunately, for vehicle attitudes where more than one of these antennas has a clear path to the receiving station, this practice also leads to self-interference nulls, resulting in dramatic degradation in the average signal integrity. This paper discusses application of unitary space-time codes such as the Alamouti transmit diversity scheme and unitary differential space-time codes to overcome the self-interference effect observed in such systems. The mathematical foundations of these techniques within the context of this application as well as computational performance gains associated with their implementation are provided. Issues such as the cost of channel estimation for trained techniques as well as the throughput performance of nondifferential and differential schemes for realistic air-vehicle motion are analyzed 相似文献
974.
Jui Tsun Hung Robertazzi T.G. 《IEEE transactions on aerospace and electronic systems》2004,40(3):968-982
Recursive analytical expressions for speedup and solution time for a multilevel tree sequentially processing a divisible load under cut through switching are developed. Such cut through switching is shown to be more efficient than store and forward switching. Aerospace applications include sensor networks, radar, and satellite imagery processing. 相似文献
975.
976.
A numerical investigation of the melt flow and heat and mass transfer is carried out at the crystal growth under zero gravity, when the melt detachment from ampoule walls, crystal vibration, and various magnetic fields are active. Specific features of the melt flow are demonstrated depending on the size of a detachment zone adjacent to the crystallization boundary. The velocity of the averaged flow generated by crystal vibration is determined as a function of the vibration intensity. It is shown that the crystal vibration cannot compensate a thermal capillary flow (caused by detachment of the melt from the ampoule wall) and reduce the macrosegregation of impurities. It is shown that the application of steady and rotating magnetic fields are inefficient for all ampoule methods of crystal growth under microgravity conditions. 相似文献
977.
L. G. Blomberg J. A. Cumnock 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2004,33(12):2161-2165
Mercury has a small but intriguing magnetosphere. In this brief review, we discuss some similarities and differences between Mercury’s and Earth’s magnetospheres. In particular, we discuss how electric and magnetic field measurements can be used as a diagnostic tool to improve our understanding of the dynamics of Mercury’s magnetosphere. These points are of interest to the upcoming ESA-JAXA BepiColombo mission to Mercury. 相似文献
978.
Solar wind turbulence during the solar cycle deduced from Galileo coronal radio-sounding experiments
A.I. Efimov L.N. Samoznaev M.K. Bird I.V. Chashei D. Plettemeier 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008
Seven coronal radio-sounding campaigns were carried out during the active lifetime of the Galileo spacecraft in the years 1994–2002. The observational data analyzed in the present work are S-band frequency fluctuation measurements recorded during the solar conjunctions at different phases of solar activity cycle #23, specifically: periods near solar maximum (three conjunctions), near solar minimum (three conjunctions) and during the ascending phase (one conjunction). These data are all applicable to low heliographic latitudes, i.e. to the slow solar wind. The rms frequency fluctuation and power-law index of the frequency fluctuation temporal spectra are determined as a function of heliocentric distance. The turbulence power spectrum tends to be flatter inside ca. 20 solar radii during all phases of the solar cycle. This coincides with a transition in the flow from the inner acceleration region to the outer region of constant velocity. The radial falloff rate and absolute level of the rms frequency fluctuation are essentially invariant over the solar cycle. 相似文献
979.
Exact multisensor dynamic bias estimation with local tracks 总被引:2,自引:0,他引:2
Xiangdong Lin Bar-Shalom Y. Kirubarajan T. 《IEEE transactions on aerospace and electronic systems》2004,40(2):576-590
An exact solution is provided for the multiple sensor bias estimation problem based on local tracks. It is shown that the sensor bias estimates can be obtained dynamically using the outputs of the local (biased) state estimators. This is accomplished by manipulating the local state estimates such that they yield pseudomeasurements of the sensor biases with additive noises that are zero-mean, white, and with easily calculated covariances. These results allow evaluation of the Cramer-Rao lower bound (CRLB) on the covariance of the sensor bias estimates, i.e., a quantification of the available information about the sensor biases in any scenario. Monte Carlo simulations show that this method has significant improvement in performance with reduced rms errors of 70% compared with commonly used decoupled Kalman filter. Furthermore, the new method is shown to be statistically efficient, i.e., it meets the CRLB. The extension of the new technique for dynamically varying sensor biases is also presented. 相似文献
980.
In preparation for the flyby of the Rosetta spacecraft, the state of the knowledge of 21 Lutetia and 2867 Steins obtained
by ground based observations is reported. Preliminary determination of shape and/or size, rotational properties and taxonomic
types are presented for both asteroids. The dusty environment of the targets has been studied in order to help in defining
safe fly-by trajectories without the risk of damaging collisions. The expected science return from the asteroid fly-by is
also discussed. 相似文献