The present study explores the functions of code-switching and the factors which motivate speakers to use it in the context of informal conversations among educated, multilingual Sindhi women at four colleges in Hyderabad and Kotri, Pakistan. Following on from such scholars as Blom and Gumperz (1972), Gumperz (1982), Myers-Scotton (1993a), Poplack (1980), this study uses a qualitative methodology consisting of audio recordings of informal interactions, the questionnaires filled in by the participants, which reveal their demographic information and observation notes by the researcher during the audio recordings. The data is then analysed using an interpretive approach. The findings provide evidence that code-switching is employed as a language strategy to achieve particular social goals. Multilingual code-switching into Sindhi, Urdu and English and a few instances of Arabic and other local languages provide sufficient evidence of participants' linguistic competence. The majority of participants use Sindhi as their L1 and English as their preferred language for code-switching. However, some participants who are Sindhi by ethnicity but acquired Urdu (their academic language) as their L1 predominantly use Urdu. The findings suggest that the participants use code switching to achieve particular social goals, such as to construct multiple identities, to express anger and humour, to discuss taboo issues and for specific textual functions such as recycling, self-repair, quotation, and idiomatic expressions. In the current study, the motivational extra-linguistic factors for the use of code-switching are historical-socio-economic factors, participants' social networks, conversational topics, and the social status of their interlocutor(s). The intra-linguistic factors consist of speakers' expression of their emotions and their linguistic competence. The most significant factor involved in the presence and absence of the use of codeswitching is the socioeconomic status of the participants. The results show the use of a huge number of English loanwords to fill lexical gaps which exist in Sindhi and Urdu. However, some instances of core borrowing (widespread borrowing in presence of equivalent in native language) from English are also used.

This thesis presents the potential opportunities of global asset allocation and the possible enhancement of these opportunities from using a Markov Switching Model. The thesis extends upon previous conditional asset pricing studies in global asset allocation, such as those done by Ilamnen (1995), Harvey, Solnik and Zhou (1992) and Bilson (1993), where expected future returns are forecast based on conditional variables. The finding of these studies, and many others, are combined with the works on Markov Switching models and market segmentation theories to create a uniform structure for analysing regime switching properties in currencies, international equities and international bond markets. This thesis is segregated into 4 major sections. The chapters 1-4 develop a unified framework that is used in the analysis of markets. The chapters 5-7 are focused on currencies, international equities and international bonds. For each market a model is constructed that is based upon the structure proposed by Frankel and Froot (1988). In this model the market is segmented into two groups ?? value based investors and momentum based investors. To replicate this structure, a two regime Markov Switching model is used, where one regime is constructed as a value regime and the second is constructed as a momentum regime. These models are then compared to linear versions of the models, to see whether there is any additional benefit to the application of regime switching methods. In conjunction with testing the potential benefits of the Markov Regime Switching process, this study also investigates the very nature, or characteristics of regime switching in the international markets. This is undertaken though some alternate models and enhancements to see whether there is any predictability, or characterisations can be made of the switching process. To ensure a comprehensive analysis, several analytical methods have been used, including extensive econometric modelling, statistical analysis of forecasts and portfolio back testing. A number of conclusions can be drawn from the results. Firstly it appears that there is substantial evidence of regime switching in international markets, such as that shown in a Frankel-Froot framework. This in turn has major implication for the understanding of the way in which international markets function, and further the empirical evidence supports many of the anecdotal observations of market based participants. Secondly, there appears to be a strong level of economic relevance to the modelling. The models are shown to generate a theoretical economic profit, which shows that the international markets are only semi efficient. Further, forecasts generated from the Markov Switching models outperform the linear counterparts in economic significance in portfolio tests. However, for both equities and bonds, the general accuracy of the forecast tends to be inferior to the linear counterparts. Finally, the nature of regime switching is investigated in detail, particularly in reference to 3 potential drivers ?? greed, fear and success. The evidence shows that these can help explain the characteristics of regime switching, as in some cases potentially adding economic value. However, it seems that success is more important than a broader economic environment.

Graduation date: 1995

A 4 × 4 photonic switch matrix was designed, fabricated and characterized. The photonic switch matrix was based on microring resonator (MR) and was fabricated on relatively low-cost silicon-on-insulator (SOI). Independent wavelength channel switching was accomplished by thermo-optic tuning of the MRs through highly localized resistive micro-heaters. The device was fabricated using the relatively mature silicon fabrication technology. Waveguide patterns were defined with high definition eBeam lithography, etching was done in a reactive-ion etching chamber, and the top cladding SiO2 layer was deposited through plasma-enhanced chemical vapor deposition. Finally, resistive Nichrome micro-heaters were deposited locally directly above each MR to offer the dynamic tuning capability. The strong optical confinement offered by the high index contrast between silicon and SiO2 makes it possible to fabricate micrometer-sized MRs with acceptable optical power loss caused by the small bending radii. The MRs were designed with a uniform diameter of 10 µm to support a wide free spectral range. All waveguides have a design dimension of 450 nm × 250 nm to allow operation exclusively in the fundamental mode at the 1.55 µm wavelength. A FSR of 18 nm with a spectral linewidth of 0.1 nm were observed for the fabricated MRs offering high wavelength selectivity. The device exhibits virtually no thermal crosstalk between adjacent channels, showing no output peak wavelength shift at 0.01 nm wavelength measurement precision by thermally tuning an adjacent MR with electric current as high as 7 mA, which is equivalent to about 2.5 nm in resonance wavelength tuning. The device showed a tuning delay time of about 1 ms. The overall bare chip size of the device is 20 mm × 4 mm. We demonstrated through this work a wavelength selective photonic switch device using low-cost SOI technology that is compact and easy to fabricate. It shows high potential for further development into high port-count photonic switch matrix.

Thesis (M.C.E.)--University of Delaware, 2006. / Principal faculty advisor: Ardeshir Faghri, Dept. of Civil & Environmental Engineering. Includes bibliographical references.

Todays supercomputers employ the fastest processors incorporating the latest VLSI technology. Unfortunately, usable system performance is often limited by excessive interprocessor latency. To overcome this bottleneck, this thesis explores the use of all-optical path interconnection networks using a new topology defined by Coke Reed [31]. This work overcomes limitations of previous optical networks through a novel use of defection routing to minimize latency and allow more processors to collaborate on the same application and dataset. In this thesis research, the data vortex is formally characterized and tested for performance. Extra angles serve as virtual buffers to provide required system performance, even under asymmetric mode operation. The data vortex is compared to two well-known interconnection networks (omega and butterfly) using metrics of average latency and message acceptance rate. The data vortex is shown to outperform the comparison networks, with a 20-50% higher acceptance rate and comparable average latency. The impact of angle size is also studied, and a new, synchronous mode of operation is proposed where additional angles are added to increase the virtual buffering of the network. The tradeoff between virtual buffering and angle resolution backpressure is explored, and an optimal point is found at the 1:6 I/O to non-I/O (virtual buffering) angle ratio. The new mode and optimal angle count are used to form data vortex networks that perform as well as larger networks with fewer total nodes. Finally, hierarchical layering with data vortex clusters is proposed and compared to a single-level data vortex. In todays technology, similar performance is attained at high network communication locality loads (> 2/3), and a 19% latency reduction is obtained at the highest locality loads (> 95%) for current optical switching technology. For projected future technology, the clustered system is shown to yield up to a 55% reduction in latency for applications with 2/3 or better locality.

Task-switching studies are a popular measure of executive control, yet the influence of stimulus repetition in these studies is less well recognized. One theory from the literature states that stimuli associated with a certain response interfere with processing of those same stimuli in another task, contributing to task switching costs (Waszak, Hommel, &Allport, 2003). The current study varied stimulus repetition in younger and older adults and found that the previous task associated with a stimulus does influence overall performance but did not find the expected interaction of switch and repetition conditions. Results of this study extend our information about the role of stimulus repetition in task-switching studies as well as how this repetition relates to age differences in switch costs.

This research studied the polarization switching during theturned on of a VCSEL. The switching periods and beam profilewere investigated by the variation of the driving current and heat sink temperature of the laser. The laser would present a series of polarization switching before it achieved the stable state. At a laser¡¦s current of 5.5 mA, the laser first output in Y-polarization for a period of T1 after the laser was turned on. Then the laser switched to X-polarization and maintained for a period of T2. In the third period of T3, the laser switched to Y-polarization and followed by a final switch to X-polarization. We found that the switching periods would decrease under higher temperature and larger driving current, while the ratio of T2 /T1 and T3/T2 did not change, approximating to a constant of e2.We also found that the beam profile of X-polarization would change periodically with a period of 0.32 mA in the region of 3.5 to 6.0 mA. These results will help to understand the mechanism of the polarization switching when the laser is turned on.

Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 104-108). Also available on the World Wide Web.

Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2004. / Verriest, Erik, Committee Member ; Wardi, Yorai, Committee Member ; Yezzi, Anthony, Committee Member ; Wang, Yang, Committee Member ; Egerstedt, Magnus, Committee Chair. Vita. Includes bibliographical references (leaves 80-85).