Abstract: Systems and methods which provide for learning, particularly learning in a professional school environment, that allow for interactive question and answer study sessions in the form of learning tutorials and test preparation modules which can be used in conjunction with traditional classroom learning techniques or other learning techniques and provide for improved interactivity and presentation compared to traditional systems.

Abstract: A magnetic sensing device that senses low frequency magnetic fields by using movable flux concentrators that modulate the observed low frequency signal. The concentrator oscillates at a modulation frequency much greater than the observed magnetic field being sensed by the device. The modulation shifts this observed signal to higher frequencies and thus minimizes 1/f-type noise. This is preferably accomplished by the oscillatory motion of a microelectromechanical (MEMS)—type magnetic flux concentrator operated with a magnetic sensor, preferably made on a common substrate. Such a combined device can be used in a magnetometer. Such a device is small, low-cost and has low-power-consumption requirements. The magnetic sensor can be a Hall effect or other type of magnetic sensor. At least one modulating flux concentrator is used with the magnetic sensor.

Abstract: An incriment optical signal from a potential enemy threat is captured by an array of apertures which are connected to a number of broadband filters. The broadband filters have overlapping band pass regions to cover the wavelength spectrum of potential threats, but not with the spectral resolution of a larger number of narrowband filters. To further increase resolution without adding additional filters, each broadband filter is connected to an optical delay line which converts wavelength into a time delay. To enable measurement of the time delay, additional optical lines with no relative delay are connected directly from the apertures. The time difference between when a signal arrives over optical delay lines from the filters and when a signal arrives over optical lines directly from the array of apertures is then reconverted to wavelength to a high degree of resolution.