A circuit design of baseband transceiver for direct sequence ultra-wide band system is presented in this thesis. A low complexity Viterbi decoder is also proposed. This Viterbi decoder circuit is based on compare-select-add unit and trace-forward architecture. The decision bit operator is reduced to one adder and this can lower down the hardware complexity. Further, two trace-forward operators are used in the survivor management unit. Only two single port SRAM¡¦s with a length of T are applied for reducing the area of memory. The chip is implemented by TSMC standard 0.18-£gm 1P6M CMOS process with core area 1.061 ¡Ñ 1.069 mm2. The post-layout simulation with 1.8V supply at 25 shows that the proposed direct sequence ultra-wide band system of baseband transceiver chip can work above 141 MHz with 86.41 mW power dissipation.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references. Also available in electronic version. Access restricted to campus users.

Thesis (M. Phil.)--University of Hong Kong, 1987.

Thesis (M. Phil.)--University of Hong Kong, 1977.

The objective of the thesis is to investigate the trace formulas and their applications on Hecke eigenvalues, especially on the distribution of Hecke eigenvalues. This thesis is divided into two parts.. In the first part of the thesis, a review is firstly carried out for the equidistribution of Hecke eigenvalues as primes vary and for the expected size of the error term in this equidistribution problem. Then the Kuznetsov trace formula is applied to prove a result on the size of the error term in the asymptotic distribution formula of Hecke eigenvalues. These eigenvalues become equidistributed with respect to the p-adic Plancherel measures as Hecke eigenforms vary. Next, this problem is generalized to Satake parameters of GL2 representations with prescribed supercuspidal local representations. Such a generalization is novel to the case of classical automorphic forms. To achieve this result, a trace formula of Arthur-Selberg type with a couple of key refinements is used. In the second part of the thesis, a density theorem is proved which counts the number of exceptional nontrivial zeros of a family of symmetric power L-functions attached to primitive Maass forms in the critical strip. In addition, a large sieve inequality of Elliott-Montgomery-Vaughan type for primitive Maass forms is established. The density theorem and large sieve inequality have many applications. For instance, they are used to prove statistical results on Hecke eigenvalues of primitive Maass forms and the extreme values of the symmetric power L-functions attached to primitive Maass forms. / published_or_final_version / Mathematics / Doctoral / Doctor of Philosophy

Trace element compositions, expressed as ratios relative to Ca (Mg/Ca, Sr/Ca and Ba/Ca), in drip water and modern speleothem calcite were measured at multiple sites within a single cave system (Natural Bridge Caverns) in central Texas. These measurements are used to investigate how water and calcite compositions respond to changes in climate. Drip water trace element ratios respond to changes in climate and in soil, vadose zone and/or in-cave processes, which are in turn influenced by climate. It is commonly assumed that speleothem calcite directly reflects these changes in the drip water composition. To test this assumption, this study quantifies the partitioning of trace elements into speleothem calcite in a natural cave setting. To determine the controls on calcite trace element ratios, empirical partition coefficients (K [subscript D]) for Mg, Sr, and Ba are measured using a unique time series of water and modern calcite geochemistry at two drip sites. One drip site, dominantly supplied by conduit flow, has relatively invariant calcite trace element compositions that reflect correspondingly small variations in drip water chemistry. A second drip site, supplied by a combination of conduit and diffuse flow, exhibits a seasonal change in drip water composition due to changes in cave-air CO₂ concentrations. The drip water seasonality at this site is recorded in the calcite trace element compositions; however the partitioning of Mg/Ca from drip water to calcite is not controlled by the same mechanism(s) that control Sr/Ca and Ba/Ca partitioning. Results of this study indicate that the partitioning of Mg changes with drip water Mg concentration, temperature and location of the calcite relative to the point of drip impact. Calcite Sr/Ca and Ba/Ca ratios are more strongly influenced by changes in cave-air CO₂ that cause changes in CO₂ degassing, affecting calcite precipitation. This element specific partitioning complicates the interpretation of speleothem trace element records, since calcite Mg/Ca and Sr/Ca may not always covary even at drip sites that experience PCP. Although there is a strong correlation between Mg/Ca and Sr/Ca ratios in the drip water at these sites, there is considerable scatter between these two values in calcite. Average K [subscript D] values at both sites fall within the range of previous theoretical and empirical studies and are 0.025, 0.12 and 0.15 for Mg, Sr and Ba respectively. It is important to note that not all trace element partitioning is controlled by the same mechanism, since this has implications for interpretations of hydrologic processes from speleothems. / text

Das als Trace bezeichnete nicht-invasive Aufzeichnen von Systemzuständen, während ein eingebettetes System unter realen Einsatzbedingungen in Echtzeit läuft und mit der Systemumgebung interagiert, ist ein wichtiger Teil von Softwaretests. Die Notwendigkeit für den On-Chip-Trace resultiert aus der rückläufigen Einsetzbarkeit etablierter Werkzeuge für den Off-Chip-Trace. Ein wesentlicher Bestandteil von On-Chip-Trace-Architekturen ist die Volumenreduktion der Tracedaten in deren Entstehungsgeschwindigkeit direkt auf dem Chip. Der Schwerpunkt liegt auf dem Trace des Instruktionsflusses von Prozessoren. Der aktuelle Stand der Forschung zeigt zwei Ausprägungen. Bei einfachen Lösungen ist der Kompressionsfaktor zu klein. Aufwendigere Lösungen liefern einen unvollständigen Instruktionstrace, wenn auch sequentielle Befehle bedingt ausgeführt werden. Bisher existieren keine Lösungen, die einen vollständigen Instruktionstrace mit hoher Kompression realisieren. Diese Lücke wird in der vorliegenden Arbeit geschlossen. Der systematische Entwurf der neuen On-Chip-Trace-Architektur beginnt mit der umfassenden Analyse typischer Benchmarkprogramme. Aus den Ergebnissen werden grundlegende Entwurfsentscheidungen abgeleitet. Diese Bitsequenzen von Ausführungsbits, die bei der bedingten Befehlsausführung entstehen, und die Zieladressen ausgeführter indirekter Sprünge werden in unabhängigen Kompressoren verarbeitet. Ein nachgeschalteter Kompressor für die Messages der anderen beiden Kompressoren ist optional und kann die Kompression weiter steigern. Diese Aufteilung stellt ein architektonisches Novum dar. Die Kompression von Bitsequenzen ist bisher ein weitestgehend unbehandeltes Feld. Implementiert worden ist hierfür ein gleitendes Wörterbuch mit der Granularität von Einzelbits. Die Vergleiche mit den untersuchten existierenden Architekturen zeigen die Überlegenheit der neuen Architektur bei der Kompression. Ein vollständiger Instruktionstrace ist für Prozessoren mit und ohne bedingt ausführbaren sequentiellen Befehlen realisiert worden.

The trace element content of clinkers (and possibly of cements) can be used to identify the manufacturing factory. The Mg, Sr, Ba, Mn, Ti, Zr, Zn and V content of clinkers give detailed information for the determination of the origin of clinkers produced in different factories. However, for the analysis of such complex data there is a need for algorithmic tools for the visualization and clustering of the samples. This paper proposes a new approach for this purpose. The analytical data are transformed into a twodimensional latent space by factor analysis (probabilistic principal component analysis) and dendograms are constructed for cluster formation. The classification of South African clinkers is used as an illustrative example for the approach.

No description available.

No description available.