Potential defense applications of expert systems

The authors provide an overview of expert systems and how they may effect the development of future defense applications. Military uses of computers are outlined, and expert-systems fundamentals are described. Artificial research and development efforts by the military are examined, and potential military applications are discussed. Expert systems efforts at NASA, by the US Air Force, and for the Strategic Defence Initiative are considered     

Preliminary data of the thermal regime and circulation in the upper mesosphere and mesopause

Circulation and thermal structure for the 90–95 km region is described on the basis of the joint analysis of direct and indirect sounding data. Mean season charts of the 0.001 mb surface were compiled using data from meteor trials, ionospheric drifts, rocket launchings and data of the rotational temperature of hydroxyl emission.     

Some aspects of the application of the bunch of MPD engines

In the present work, the asymptotic dependence of the reservation multiplicity on the failure danger diminution coefficient in both cases of reservation replacement and continually acting reserver is investigated. The comparison of the method of reservation for different multiplicities with the method of diminution of the failure intensity, related to the mean performance time shows that the decrease of the failure intensity of the plazma engine is the most rational. Nevertheless, there is a value of the time flight for which even a simple duplication is better than arbitrarily large, though finite, failure intensity decrease of the engine. The reliability of coupled MOD-thrusters is verified experimentally. The specific character of the thruster V-I curves and, in particular, their increase in the pubricrcrisis region, yield normally working couples, conformly to many types of feed sources with weakly decreasing of constant V-I characteristics. The parallel connection of a second thruster is shown to double the customed current and, as a consequence the thruster intermediary regimes of the thruster and the dynamics of switching on and by breaking the electric line and stopping the propellant rate flow are investigated.     

Telerobotics: problems and research needs

With major emphasis on simulation, a university laboratory telerobotics facility permits problems to be approached by groups of graduate students. Helmet-mounded displays provide realism; the slaving of the display to the human operator's viewpoint gives a sense of `telepresence' that may be useful for prolonged tasks. Using top-down 3-D model control of distant images allows distant images to be reduced to a few parameters to update the model used for display to the human operator in a preview model to circumvent, in part, the communication delay. Also, the model can be used as a format for supervisory control and permit short-term local autonomous operations. Image processing algorithms can be made simpler and faster without trying to construct sensible images from the bottom. Control studies of telerobots lead to preferential manual control modes and, in this university environment, to basic paradigms for human motion and thence, perhaps, to redesign of robotic control, trajectory path planning, and rehabilitation prosthetics. Speculation as to future industrial drives for this telerobotic field suggests efficient roles for government agencies such as NASA     

A noise insensitive solution to an ambiguity problem in spectralestimation

The instantaneous frequency measurement (IFM) receiver is capable of measuring the center frequency of single frequency pulses over a wide range (bandwidth) of center frequencies. Because of various constraints, the frequency resolution requirement results in long correlator delay times that reduce the single correlator bandwidth. A large bandwidth can be achieved only if two or more correlators are used. The problem of estimating frequency is then reduced to the simultaneous congruence problem of number theory. A design procedure is presented for solving the congruence problem for a given amount of noise protection, a stated frequency resolution, a minimum bandwidth, and a fixed level of precision (bits) in the IFM receiver     

Confirmation of gravisensitivity in the slime mold physarum polycephalum under near weightlessness

We have investigated Physarum polycephalum, a unicellular organism with no special gravity receptors, on its ability to react to gravity. The first experiments were 0 g-simulation experiments on the fast-rotating clinostat conducted with plasmodial strands of this acellular slime mold. In these earth-bound experiments the observed parameters were periodicity of the contractions and dilatations of the strand's ectoplasm as well as the periodicity and velocity of the striking cytoplasmic (endoplasmic) shuttle streaming. During 0 g-simulation these parameters showed significant changes indicating the existence of a gravisensitivity of the slime mold.

The Space-Shuttle experiment (ESA-Biorack in D 1-Mission) should demonstrate the validity of the 0 g-simulation on the fast-rotating clinostat. The experiment was designed in a way enabling the registration of the same parameters as on the clinostat (using the light microscope in combination with a photo diode and a cinecamera). Only one of the two planned measurement sessions was fully successful and provided us with data confirming the results gained on the fast-rotating clinostat: The slime mold showed under real near weightlessness in the D 1-Space Shuttle Mission a transient frequency increase in its contraction rhythmicity and a (steady) increase in the streaming velocity of its endoplasm.     

Effects of prolonged exposure to space flight factors for 175 days on lettuce seeds

We have studied the effects of prolonged (up to 175 days) exposure of $\text{Lactuca sativa}$ seeds to space flight factors, including primary cosmic radiation heavy ions. The data obtained evidence a significant fourfold increase ofs pontaneous mutagenesis in seeds both with regard to the total number of aberrant cells as well as the formation of single cells with multiple aberrations. Comparison of the present experiment with earlier works shows that the frequency of such aberrations increases with the duration of the flight.     

On the conditions of gas inclusions formation in melts under zero gravity state (after “Pirin” experiment)

Thermodynamics relations have been considered under which gas inclusions may form in melts (closed systems), due to both volatility of components and the presence of dissolved gases. It has been shown that in the melts with sufficient volatility of components, gas inclusions may form under equilibrium conditions if the ampoule is wetted well by the melt, whereas in case of low wettability they form under non-equilibrium state only. The foaming in the tellurium-selenium system has been analysed (“Pirin”, KP-4 experiment).In the melts containing dissolved gases, gas inclusions form under conditions of deviation from equilibrium and it is the main mechanism of outgassing. It has been demonstrated that the melt foaming method using hydrid compounds may be applied to the materials exhibiting a hysteresis of temperature dependence of diluted hydrogen concentration. Production of foam aluminium under zero gravity state has been considered as an example (“Pirin”, SP-3 experiment).     

Asymptotic Reproducibility in Nonlinear Systems and Attitude Control of Gyrostat

A control law is presented for asymptotic function reproducibility in a class of nonlinear-systems such that the output of the system asympotically tends to a given function. The controller consists of a prefilter and a servocompensator. Based on this result, a nonlinear feedback control law for the attitude control of a satellite containing symmetric rotors, in a circular orbit, is derived. In the closed-loop system, given trajectories of pitch, yaw, and roll angles are asymptotically followed, and set point control of attitude is accomplished. Digital simulation results are presented to show the capability of the nonlinear controller.