No description available.

No description available.

A solar spectroradiometer is an instrument used for measuring the transmitted solar radiation on a quasi-continuous basis. An existing computer controlled solar spectroradiometer system has been modified and made operable. Test measurements have shown that the signal to noise ratio (which is time of day and wavelength dependent) is at an acceptable level. The chief use of the spectroradiometer will be for atmospheric transmittance studies, which will require calibration of the instrument. Strategies for calibrating the instrument have been discussed.

The method of measuring the energy of a charged particle by means of the total amount of ionisation it produces in a gas, through which it passes, is well established. Gas filled devices may be subdivided into (a) current ionisation chambers and (b) pulse ionisation chambers, proportional counters and Geiger counters. Proportional counters in a very crude form were used by Rutherford and Geiger in 1908. Soon afterwards the Geiger counter was developed, which after considerable improvement by Geiger and Müller in 1928, became the well known Geiger-Müller counter. In fact the three gas filled devices mentioned in (b) can be achieved with the same counter by using it with different applied voltages. If the applied voltage on a typical cylindrical counter is varied and the output pulse height is measured for a fixed number of ion pairs liberated in the gas, a characteristic curve of the form shown in Fig.(1) will be obtained. With voltages between say v₁ and v₂, the field strength is just sufficient to collect all the ion-pairs and no new ion-pairs are liberated, so the pulse height will remain constant. This is the region of pulse ionization chambers where the gas gain is unity. As the voltage is further increased to between v₂ and v₃ both elastic and inelastic collisions take place and the pulse height increases exponentially.

by Ng Yee Kong. / Chinese title in romanization: Mo chong ji guang ruo fu she fa ce liang gao zhu wu bo mo di dao wen xi shu. / Thesis (M.Ph.)--Chinese University of Hong Kong, 1987. / Bibliography: leaves 148-150.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Digitized by Kansas Correctional Industries

Graduation date: 1999 / Best scan available.

Graduation date: 2001

A novel method of human presence detection using passive millimeter-wave sensors is presented. The method focuses on detecting a standing human from a moving platform in a cluttered outdoor environment using millimeter-wave radiometry, which has not been attempted before. Ka-band radiometers are used in total power mode as well as correlation mode, which ideally responds well to self-luminous objects such as humans. The intrinsic radiative power from a human is derived as well as the responses of the total power and correlation mode. The application of correlation radiometer theory to the detection of self-luminous objects at close range is presented in the context of human presence detection. Modifications and additions to techniques developed in radio astronomy and remote sensing for close range terrestrial situations are developed and discussed. The correlation radiometer fringe frequency is analyzed in the context of the scanning beam detection system and is estimated using MUSIC and ESPRIT. Detection and classification of humans is accomplished using a Naïve Bayesian classifier. The performance of the classifier is measured using the F1-measure and the receiver operating characteristic. / text