Thesis--Wisconsin. / Includes bibliographical references (leaves 110-111).

Despite a large investment, the majority of countries especially the UK demonstrate a slow adoption of broadband. In order to enhance the adoption and use of broadband this research examines the factors influencing the decisions of household consumers. This research aims to address the two main areas of concern: first, to investigate consumer-level factors affecting the adoption of broadband in UK households; and second, to understand the usage of broadband and its impact upon household consumers in the UK. This research adopted a quantitative approach that was executed in the following steps. First, it developed a conceptual model by selecting and justifying relevant constructs from appropriate theories and models related to technology adoption, usage and impact. Second, it operationalised the constructs by developing and validating the research instrument by employing the content validity, reliability and construct validity approach. Finally, it empirically validated and refined the conceptual model by employing a survey research approach. The findings suggested that all the constructs included in the conceptual model, except knowledge, significantly influence the consumers when adopting broadband in a UK household. The significant constructs include relative advantage, utilitarian outcomes, hedonic outcomes, primary influence, facilitating conditions resources and self-efficacy. The rate and variety of Internet usage is significantly higher for broadband consumers than narrowband ones. It was also found that significantly more numbers of broadband consumers perceived changes in time allocation patterns on various daily life activities than narrowband ones. This research contributes towards theory, practice and policy. The contribution of this research towards theory is that it integrates and determines the appropriate information systems (IS) literature in order to enhance knowledge of technology adoption from the consumers' perspectives. An added contribution to theory is the development and validation of a research instrument that future studies can utilise to examine broadband and other similar technologies in household context. Considering the slow adoption of broadband, this research also provides implications for policy makers and the providers of broadband in order to encourage and promote homogenous adoption and usage.

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Yau Chi-kit. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 149-151). / Abstracts in English and Chinese. / Abstract / Acknowledgements / Table of Contents / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Background Theory --- p.5 / Chapter 2.1 --- Power Dividers and Couplers --- p.5 / Chapter 2.1.1 --- 3dB Wilkinson Power Divider --- p.5 / Chapter 2.1.2 --- Branch Line Coupler --- p.9 / Chapter 2.2 --- Balanced Amplifier --- p.11 / Chapter 2.2.1 --- Working Mechanism of Balanced Amplifier --- p.11 / Chapter 2.2.2 --- Effects of Coupler's Phase Imbalance and Gain Mismatch --- p.15 / Chapter 2.3 --- Low Temperature Co-fired Ceramic (LTCC) Technology --- p.21 / Chapter 2.3.1 --- Overview of LTCC Technology --- p.21 / Chapter 2.3.2 --- LTCC Material Properties and Performance --- p.23 / Chapter 2.3.3 --- Advantages and Disadvantages of LTCC Technology --- p.24 / Chapter Chapter 3 --- LTCC Basic Components Characterization --- p.27 / Chapter 3.1 --- Embedded Capacitors --- p.28 / Chapter 3.1.1 --- Vertical Structure for Embedded Capacitors --- p.28 / Chapter 3.1.2 --- Shunt Capacitor --- p.29 / Chapter 3.1.3 --- Series Capacitor --- p.45 / Chapter 3.2 --- Embedded Inductors --- p.54 / Chapter 3.2.1 --- Shunt Inductor --- p.54 / Chapter 3.2.2 --- Series Inductor --- p.61 / Chapter Chapter 4 --- Design Methodology for LTCC Integrated Passive Devices (IPD) --- p.69 / Chapter 4.1 --- LTCC Circuit Design Roadmap --- p.70 / Chapter 4.2 --- Design of a 1.88GHz Lumped Element 3dB Branch Line Coupler --- p.73 / Chapter 4.2.1 --- Vertical Structure --- p.73 / Chapter 4.2.2 --- Design Specifications --- p.74 / Chapter 4.2.3 --- Schematic Design --- p.74 / Chapter 4.2.4 --- Design Library --- p.79 / Chapter 4.2.5 --- Commercial EM Simulator --- p.83 / Chapter 4.2.6 --- Layout and Optimization Designs --- p.89 / Chapter 4.3 --- Design of a 1.88GHz Lumped Element 3dB Wilkinson's Power Divider with 90° phase difference between two outputs --- p.96 / Chapter 4.4 --- 3-port Measurement Technique --- p.106 / Chapter Chapter 5 --- Noise Analysis and Noise Parameters Measurement --- p.110 / Chapter 5.1 --- Noise Figure of an Amplifier --- p.110 / Chapter 5.2 --- Noise Correlation Matrices --- p.114 / Chapter 5.2.1 --- Definition --- p.114 / Chapter 5.2.2 --- Transformation of Representation --- p.116 / Chapter 5.2.3 --- Connection of Correlation Matrices --- p.117 / Chapter 5.3 --- Noise Characterization --- p.118 / Chapter 5.3.1 --- Conventional Measurement Technique --- p.118 / Chapter 5.3.2 --- Determination of Noise Parameters Using Four Nonsingular Measurements --- p.119 / Chapter 5.3.3 --- A De-embedding Technique for Extracting Noise Parameters --- p.121 / Chapter Chapter 6 --- Design of a 1.88GHz LTCC Balanced LNA --- p.126 / Chapter 6.1 --- Design Specifications --- p.126 / Chapter 6.2 --- Design of LTCC D.C. Biasing Circuit --- p.128 / Chapter 6.3 --- Stability Consideration --- p.129 / Chapter 6.4 --- Matching Networks Design --- p.133 / Chapter 6.4.1 --- Input Matching Network --- p.133 / Chapter 6.4.2 --- Output Matching Network --- p.136 / Chapter 6.5 --- Design of the LTCC Balanced LNA --- p.140 / Chapter Chapter 7 --- Conclusion and Future Work --- p.148 / References --- p.149 / Author's Publication --- p.152 / Appendix A Even and Odd Modes Analysis for Power Dividers --- p.153 / Appendix B TRL Calibration Technique --- p.162

Thesis advisor: Michael J. Naughton / Thesis advisor: John E. Ebel / Determining accurate source parameters of small magnitude earthquakes is important to understand the source physics and tectonic processes that activate a seismic source as well as to make more accurate estimates of the probabilities of the recurrences of large earthquakes based on the statistics of smaller earthquakes. The accurate determination of the focal depths and focal mechanisms of small earthquakes is required to constrain the potential seismic source zones of future large earthquakes, whereas the accurate determination of seismic moment is required to calculate the sizes (best represented by moment magnitudes) of earthquakes. The precise determination of focal depths, moment magnitudes and focal mechanisms of small earthquakes can help greatly advance our knowledge of the potentially active faults in an area and thus help to produce accurate seismic hazard and risk maps for that area. Focal depths, moment magnitudes and focal mechanisms of earthquakes with magnitudes Mw 4.0 and less recorded by a sparse seismic network are usually poorly constrained due to the lack of an appropriate method applicable to find these parameters with a sparse set of observations. This dissertation presents a new method that can accurately determine focal depths, moment magnitudes and focal mechanisms of earthquakes with magnitudes between Mw 4.0 and Mw 2.5 using the broadband seismic waveforms recorded by the local and regional seismic stations. For the determination of the focal depths and the moment magnitudes, the observed seismograms as well as synthetic seismograms are filtered through a bandpass filter of 1-3 Hz, whereas for the determination of the focal mechanisms, they are filtered through a bandpass filter of 1.5-2.5 Hz. Both of these frequency passbands have a good signal-to-noise ratio (SNR) for the small earthquakes of the magnitudes that are analyzed in this dissertation. The waveforms are processed to their envelopes in order to make the waveforms relatively simple for the modeling. A grid search is performed over all possible dip, rake and strike angles and as well as over possible depths and scalar moments to find the optimal value of the focal depth and the optimal value of the scalar moment. To find the optimal focal mechanism, a non-linear moment-tensor inversion is performed in addition to the coarse grid search over the possible dip, rake and strike angles at a fixed value of focal depth and a fixed value of scalar moment. The method of this dissertation is tested on 18 aftershocks of Mw between 3.70 and 2.60 of the 2011 Mineral, Virginia Mw 5.7 earthquake. The method is also tested on 5 aftershocks of Mw between 3.62 and 2.63 of the 2013 Ladysmith, Quebec Mw 4.5 earthquake. Reliable focal depths and moment magnitudes are obtained for all of these events using waveforms from as few as 1 seismic station within the epicentral distance of 68-424 km with SNR greater or equal to 5. Similarly, reliable focal mechanisms are obtained for all of the events with Mw 3.70-3.04 using waveforms from at least 3 seismic stations within the epicentral distance of 60-350 km each with SNR greater or equal to 10. Tests show that the moment magnitudes and focal depths are not very sensitive to the crustal model used, although systematic variations in the focal depths are observed with the total crustal thickness. Tests also show that the focal mechanisms obtained with the different crustal structures vary with the Kagan angle of 30o on average for the events and the crustal structures tested. This means that the event moment magnitudes and event focal mechanism determinations are only somewhat sensitive to the uncertainties in the crustal models tested. The method is applied to some aftershocks of the Mw 7.8, 2015 Gorkha, Nepal earthquake which shows that the method developed in this dissertation, by analyzing data from eastern North America, appears to give good results when applied in a very different tectonic environment in a different part of the world. This study confirms that the method of modeling envelopes of seismic waveforms developed in this dissertation can be used to extract accurate focal depths and moment magnitudes of earthquakes with Mw 3.70-2.60 using broadband seismic data recorded by local and regional seismic stations at epicentral distances of 68-424 km and accurate focal mechanisms of earthquakes with Mw 3.70-3.04 using broadband seismic data recorded by local and regional seismic stations at epicentral distances of 60-350 km. / Thesis (PhD) — Boston College, 2019. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Physics.

Due to the fast growing communication need, the required capacity of the optical fiber network has been more than doubled every year. The technology breakthrough in dry fiber fabrication opens the possibility for fiber bandwidth from 1.3 £gm to 1.6 £gm. The fast increasing demand of communication capacity results in the emergence of wavelength division multiplexing (WDM) technology, enabling tens or even hundreds of channels with different wavelengths transmitted simultaneously on an optical fiber, which results in the need for ultra-broadband optical amplifier. Cr4+:YAG has a strong spontaneous emission spectrum covers from 1.3 £gm to 1.6 £gm. In addition, its absorption spectrum is between 0.9 £gm to 1.2 £gm, which matches the pumping wavelength of current erbium doped optical amplifier. Such fiber is, therefore, eminently suitable for optical amplifier applications. In this thesis, we introduce the development of ultra-broadband optical amplifier using the Cr4+:YAG double-clad crystal fiber, which is grown by the laser-heated pedestal growth (LHPG) technique. Try to use passive tence theoretical models and numerical simulations to know we can get more than 2 dB gross gain when signal propagations two times in Cr4+:YAG double-clad crystal fiber. With the butt-coupling method, a net gain of 0.0 dB is demonstrated at 1.3W bi-directional pump power and signal double pass in Cr4+:YAG double-clad crystal fiber at present. In the future, in order to reduce pump excited-state-absorption. We attempt to use clad-pump or side-pump scheme instead of core-pump scheme, to choose pumping wavelength at 925 nm instead of 1064 nm and to use side deposition of Yb2O3 and CuO . At the same time, we will continue to fabricate small-core-diameter Cr4+:YAG DCF to achieve a single-mode fiber and to extend its length to improve gain performance.

This thesis develops an automatic lighting supervisory system (ALSS) which integrates the broadband power line communication (BPLC). The microprocessor, power line communication module and other hardware/firmware are applied in the ALSS to execute the optimal electric energy and lighting control to improve the energy usage efficiency. The ALSS consists of energy control module, BPLC module, and terminal control center. Energy control module provides the functions of electric power measurement, on/off control and lighting control. Furthermore, bidirectional communication between energy control unit and control center is possible via the usage of BPLC communication module. In this thesis, a terminal control center supports the functions of monitoring, recording and alarming. Also, it can allow users to adjust the setting values of the energy control module. Finally, the proposed ALSS is installed to a real lighting system to verify its effectiveness and value.

In this thesis, carrier dynamics and broadband THz enhancement of photoconduction based THz system are studied with double pulses pump-probe and THz system. The carrier dynamics behavior of the second pulse excitation almost remain unchanged for various temporal spacing of double pulses excitation (from 264fs to 276fs). This is attributed to faster carrier life time of material (around 270fs). Meanwhile, broadband THz enhancement is also investigated under various chirp and temporal spacing of two excitation pulses using shaping pulse THz-TDS system. Compared to typical narrowband THz enhancement, enhanced broadband THz signal both in temporal profile and power is observed at specific temporal spacing and chirp of two excitation pulses. Suitable mechanics is also discussed in this thesis.