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The aim of' this investigation is to determine the combination of signal coding and modulation for satellite links, that, for a given degree of equipment complexity needed for the detection of the received signal, achieves the best tolerance to noise. Computer simulation tests and theoretical analyses are used to compare the various proposed signal designs The trellis coded M-ary phase-shift-keyed (MPSK) modulation method is introduced as the scheme for which different codes are to be devised. A class of known binary convolutional codes for 8 and 16 PSK signals is studied, and new correlative-level codes using modulo-M arthimetic are designed for MPSK signals. The soft-decision maximum likelihood Viterbi decoding algorithm is considered for the two proposed signal designs, and a more conventional near-maximum likelihood (reduced-state Viterbi) decoding scheme is also investigated for both types of coded signals. Two novel decoding schemes, derived from a more conventional near-maximum likelihood decoder, are proposed for coded 8PSK signals. In both decoders the amount of computation involved in decoding each data-symbol is adjusted to meet the prevailing noise level in transmission. Results of extensive computer simulation tests for both decoding schemes are presented. These results suggest that the new schemes come very close to achieving the maximum likelihood decoding of the coded signals without, however, requiring nearly as much storage and computation per decoded data symbol as does the Viterbi decoder. The carrier-phase synchronisation prob1em in a coherent trellis coded MPSK system is investigated. Eight new rotationally invariant rate-2/3 and rate-3/U convolutional codes for 8 and 16 PSK signals are designed. The new coded MPSK signals, when combined with a simple phase-error correction system proposed for the receiver, are able to tolerate the likely carrier-phase changes in the reference carriers of the coherent demodulation process and therefore avoid the prolonged error bursts that are otherwise caused in the decoded data symbols by such phase shifts. coding gains of the majority of the new codes The asymptotic here are either the same as, or come close to, those of the best known but not rotationally invariant convolutional codes of the same rates.

Intrusive monitoring systems monitor the performance of data communication networks by transmitting and receiving test packets on the network being monitored. Even relatively small periods of monitoring can generate significantly large amounts of data. Primitive network performance data are details of test packets that are transmitted and received over the network under test. Network performance information is then derived by significantly processing the primitive performance data. This information may need to be correlated with information regarding the configuration and status of various network elements and the test stations. This thesis suggests that efficient processing of the collected data may be achieved by reusing and recycling the derived information in the data warehouses and information systems. This can be accomplished by pre-processing the primitive performance data to generate Intermediate Information. In addition to being able to efficiently fulfil multiple information requirements, different Intermediate Information elements at finer levels of granularity may be recycled to generate Intermediate Information elements at coarser levels of granularity. The application of these concepts in processing packet delay information from the primitive performance data has been studied. Different Intermediate Information structures possess different characteristics. Information systems can exploit these characteristics to efficiently re-cycle elements of these structures to derive the required information elements. Information systems can also dynamically select appropriate Intermediate Information structures on the basis of queries posted to the information system as well as the number of suitable Intermediate Information elements available to efficiently answer these queries. Packet loss and duplication summaries derived for different analysis windows also provide information regarding the network performance characteristics. Due to their additive nature, suitable finer granularity packet loss and duplication summaries can be added to provide coarser granularity packet loss and duplication summaries.

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International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California / The current F/A-18 data reduction/analysis system is incapable of meeting increased customer demands. A new system has been developed and is based on new technologies. In the process of developing the new system, the design team had to divorce themselves from the current system and consider what the ideal system would consist of. This was accomplished with great success in the areas of timeliness of data turn around, customer satisfaction, and increased efficiency.

Manning United States Army Reserve (USAR) units are fundamentally different from manning Regular Army (RA) units. A soldier assigned to a USAR unit must live within 75 miles or 90 minutes commute of his Reserve Center (RC). This makes reserve unit positioning a key factor in the ability to recruit to fill the unit. This thesis automates, documents, reconciles, and assembles data on over 30,000 ZIP Codes, over 800 RCs, and over 260 Military Occupational Specialties (MOSs), drawing on and integrating over a dozen disparate databases. This effort produces a single data file with demographic, vocational, and economic data on every ZIP Code in America, along with the six year results of its RA, USAR, sister service recruit production, and MOS suitability for each of the 264 MOSs. Preliminary model development accounts for about 70% recruit production variation by ZIP Code. This thesis also develops models for the top five MOSs to predict the maximum number of recruits obtained from a ZIP Code for that MOS. Examples illustrate that ZIP Codes vary in their ability to provide recruits with sufficient aptitude for technical fields. Two subsequent theses will use those results. One completes the MOS models. The second uses the models as constraints in an optimization model to position RCs. An initial version of the optimization model is developed in this thesis. Together, the three theses will provide a powerful tool for analysis of a strategic-based optimal reserve force stationing. / Lieutenant Colonel, United States Army

Canadian Precipitation Analysis (CaPA) has been developed by Environment Canada to produce the most accurate near-real-time gridded precipitation estimates. It uses the Global Environmental Multiscale model (GEM) as a background and assimilates the synoptic network of weather stations through Optimal Interpolation. Accurate estimation of gridded precipitation is useful for hydrological modeling, stream ow forecasting, and climate change studies. However, the calibration and validation of hydrologic models requires long temporal coverage of data for a better performance. Since GEM/CaPA data are available only for the recent past (2002-present), the development of historical data sets starting earlier than 2002 becomes important. Using alternative models for producing the atmospheric gridded background is one solution to overcome the short temporal coverage of archived GEM data. This thesis evaluates and analyzes two candidate data sets. ERA-Interim and NARR were selected as potential alternatives to GEM background. The general conclusion of the study is that the use of ERA-Interim and NARR as background elds leads to performance results that are not signi cantly inferior to GEM after assimilation with stations in the CaPA framework. While result with the GEM background remains the best, one can cautiously conclude that for most practical applications, ERA-Interim and/or NARR may be used for the period that predates archived GEM data. The thesis presents a more detailed evaluation of ERA-Interim and NARR for di erent seasons and di erent regions of Canada. / February 2017

QC 351 A7 no. 82 / The object of this study was to determine the utility of polarization -discrimination techniques for active optical processing. A baseline of static performance must be established before these techniques can be applied to real -time processing. The theoretical foundation for an alternative to the Vander Lugt technique of re- cording complex spatial filters had been laid by Marathay in 1969. On the basis of his theory, a photosensitive Vectograph TM technique was investigated, in which the image is produced as a polarization pattern rather than as the silver grain image of conventional photography. (1) Photographic characteristics of sensitized Vectographs were determined. The resolution ( >700 1p /mm) and the gray scale achieved indicate that the Vectograph material can also be used for recording Vander Lugt filters. (2) Theoretical analysis showed that the technique can be used to image and process objects in the same system without removal of the filter. It can also be used to generate halfwave plates for the pupil functions described by Toraldo di Francia for superresolution. (3) The Vectograph can perform addition and subtraction of functions recorded on it; it also is suitable for recording real -bipolar filter functions. (4) Variable- contrast images can be recorded. A variable-contrast Vectograph tar- get (VCVT), developed for optical testing, can not only vary the contrast of the recorded image but also reverse its contrast. In a similar fashion, a spatially variable birefringent filter (SVBF) was developed that permits spatial control of the wave- length of the transmitted light. Static and dynamic electro-optical properties of liquid crystal mixtures of cholesteryl-chloride, cholesteryl-nonanoate, and cholesteryl-oleyl-carbonate were studied to determine their feasibility as the modulator in a proposed photoconductor-liquid crystal sandwich, which would be used as a reversible recording medium. (1) Previous research had indicated that cholesteric liquid crystals are circularly dichroic in a narrow wavelength band. The present work showed that light transmitted within this band is actually elliptically polarized. The degree of ellipticity depends on the relationship between the probing wavelength and the wavelength at which the sample becomes circularly dichroic. Outside this narrow wavelength band, the crystals exhibited pure optical activity. (2) The dynamic electro-optical properties of the cholesteric trimixture were measured. An alternating electric field applied parallel to the helical axis of the liquid crystals resulted in a hysteresis in the electro-optical rotatory power of the crystals. The magnitude of the hysteresis would limit cycling of these liquid crystals to a maximum frequency of ^0.10 Hz. (3) A bias voltage applied to the crystals in an attempt to improve the frequency response resulted in a field- induced memory. When the bias voltage was maintained, the optical rotatory power failed to stabilize. Prolonged exposure to the bias voltage severely diminished the electro-optical rotatory power of the crystals.

Time resolved scanning Kerr microscopy (TRSKM) has been used to study a number of different magnetic systems. Firstly, partially built hard disk writer structures, with a multilayered yoke formed from 4 repeats of a NiFe(~1 nm)/CoFe(50 nm) bilayer, and with three coil windings underneath, were studied by TRSKM with unipolar driving pulses. Dynamic images of the in-plane magnetization suggest an underlying closure domain equilibrium state. This state is found to be modified by application of a bias magnetic field and also during pulse cycling, leading to different magnetization rotation and relaxation behaviour within the tip region. Studies of a further three yokes with the same stack structure, but with only one coil winding at different positions beneath the yoke, yielded dynamic images of “flux beaming” in a channel parallel to the driving field. The magnetic contrast was strongest when the active coil was located near the centre of the yoke, while relaxation after removal of the excitation was most complete when the active coil was located near the confluence region. These results confirm the need for a multi-turn coil to ensure effective flux propagation along the entire length of the yoke. Furthermore, a structure with a NiFe/CoFe/Ru/NiFe/CoFe synthetic antiferromagnetic (SAF) yoke was studied as a bipolar current pulse with 1MHz repetition rate was delivered to the coil. The component of magnetization parallel to the symmetry axis of the yoke was compared at the pole and above a coil winding in the centre of the yoke. The two responses are in phase as the pulse rises, but the pole piece lags the yoke as the pulse falls. The Kerr signal is smaller within the yoke than within the confluence region during pulse cycling. This suggests funneling of flux into the confluence region. Dynamic images acquired at different time delays showed that the relaxation is faster in the centre of the yoke than in the confluence region, perhaps due to the different magnetic anisotropy in these regions. Although the SAF yoke is designed to support a single domain to aid flux conduction, no obvious flux beaming was observed, suggesting the presence of a more complicated domain structure. The SAF yoke writer hence provides relatively poor flux conduction but good control of rise time compared to single layer and multi-layered yokes studied previously. Secondly, vortex dynamics within arrays of square ferromagnetic nano-elements have been studied using TRSKM with coherent microwave excitation. It is shown that TRSKM can be used to detect vortex gyration in square nanomagnets with a lateral size (250nm) that is smaller than the diameter (300nm) of the focused laser beam. In an array with large element separation and negligible dipolar interaction, TRSKM images acquired at a fixed point in the microwave cycle reveal differences in the phase of the dynamic response of individual nanomagnets. While some variation in phase can be attributed to dispersion in the size and shape of elements, the circulation and polarization of the vortex are also shown to influence the phase. In an array with element separation smaller than the optical spot size, strong magneto optical response was observed within small clusters of elements. Micromagnetic simulations performed for 2 x 2 arrays of elements show that a certain combination of circulation and polarization values is required to generate the observed magneto-optical contrast. Thirdly, polar TRSKM has been used to directly observe magnetostatically coupled transverse domain walls (TDWs) in a pair of closely spaced, curved nanowires (NWs). Kerr images of the precessional response revealed a minimum in the Kerr signal due to the TDW in the region of closest NW separation. When the TDWs were ejected from the NW pair, the minimum in the Kerr signal was no longer observed. By imaging this transition, the static decoupling field was estimated to lie between 38 and 48 Oe, in good agreement with a simple micromagnetic model. This work provides a novel technique by which DC and microwave assisted decoupling fields of TDWs may be explored in NW pairs of different width, separation, and curvature. Fourth, time resolved magneto-optical Kerr effect and phase modulated X-ray ferromagnetic resonance measurements have been performed on a CoO/Py bilayer for different temperatures, RF frequency, and CoO thickness. Kerr hysteresis loops did not show any evidence of exchange bias for temperatures between 200K and 330K for any thickness of CoO, but the coercivity was found to increase with increasing CoO thickness and decreasing temperature. Magneto-optical FMR and XFMR data showed some asymmetry with respect to the sign of the bias field, but the amplitude of the signals decreased rapidly with decreasing temperature. The results are consistent with the appearance of frustrated antiferromagnetic order within the CoO during field cooling.

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