The in-vivo observation of the neural activities generated by a large number of closely located neurons is believed to be crucial for understanding the nervous system. Moreover, the functional electrical stimulation of the central nervous system is an effective method to restore physiological functions such as limb control, sound sensation, and light perception. The Deep Brain Stimulation (DBS) is being successfully used in the treatment of tremor and rigidity associated with advanced Parkinson's disease. Cochlear implants have also been employed as an effective treatment for sensorineural deafness by means of delivering the electrical stimulation directly to the auditory nerve. The most significant contribution of this PhD study is the development of next-generation microprobes for the simultaneous stimulation and recording of the cortex and deep brain structures. For intracortical applications, millimetre length multisite microprobes that are rigid enough to penetrate into the cortex while integrated with flexible interconnection cables are demanded. In chronic applications, the flexibility of the cable minimizes the tissue damage caused by the relative micro-motion between the brain and the microprobe. Although hybrid approaches have been reported to construct such neural microprobes, these devices are brittle and may impose severe complications if they break inside the tissue. In this project, MEMS fabrication processes were employed to produce non-breakable intracortical microprobes with an improved structural design. These 32 channel devices are integrated with flexible interconnection cables and provide enough mechanical strength for penetration into the tissue. Polyimide-based flexible implants were successfully fabricated and locally reinforced at the tip with embedded 15 µm-thick gold micro-needles. In DBS applications, centimetre long microprobes capable of stimulating and recording the neural activity are required. The currently available DBS probes, manufactured by Medtronic, provide only four cylindrical shaped electrode sites, each 1.5 mm in height and 1.27 mm in diameter. Although suitable for the stimulation of a large brain volume, to measure the activity of a single neuron but to avoid measuring the average response of adjacent cells, recording sites with dimensions in the range of 10 - 20 µm are required. In this work, novel Three Dimensional (3D) multi channel microprobes were fabricated offering 32 independent stimulation and recording electrodes around the shaft of the implant. These microprobes can control the spatial distribution of the charge injected into the tissue to enhance the efficacy and minimize the adverse effects of the DBS treatment. Furthermore, the device volume has been reduced to one third the volume of a conventional Medtronic DBS lead to significantly decrease the tissue damage induced by implantation of the microprobe. For both DBS and intracortical microprobes, the impedance characteristics of the electrodes were studied in acidic and saline solutions. To reduce the channel impedance and enhance the signal to noise ratio, iridium (Ir) was electroplated on gold electrode sites. Stable electrical characteristics were demonstrated for the Ir and gold electrodes over the course of a prolonged pulse stress test for 100 million cycles. The functionality and application potential of the fabricated microprobes were confirmed by the in-vitro measurements of the neural activity in the mouse hippocampus. In order to reduce the number of channels and simplify the signal processing circuitry, multiport electrostatic-actuated switch matrices were successfully developed, fabricated, and characterized for possible integration with neural microprobes to construct a site selection matrix. Magnetic-actuated switches have been also investigated to improve the operation reliability of the MEMS switching devices.

Thesis (Ph. D.)--University of California, San Diego, 1999. / Vita. Includes bibliographical references.

Zugl.: Göteborg, Handelshögskolan, Diss., 2007

Thesis (Ph. D.)--University of California, San Diego, 1997. / Vita. Includes bibliographical references.

Thesis (M.B.A.)--University of Hong Kong, 1981. / Also available in print.

No presente trabalho, as peças Noche (número 3) e Huarache (número 4) das oito que integram a Suíte Carteles de Miguel Bernal Jiménez (México: 1910-1956) serviram de base para analisar e comparar três gravações de pianistas mexicanos e seis gravações de três pianistas brasileiros. As gravações foram analisadas com relação ao andamento e suas micro flutuações (timing), visando os aspectos comuns e discrepâncias como ponto de partida das várias possibilidades interpretativas. Foi avaliada a influência das análises e das escutas de gravações dos pianistas mexicanos apresentadas aos pianistas brasileiros. As gravações dos pianistas mexicanos já estavam disponíveis publicamente. Os pianistas brasileiros concordaram voluntariamente em participar deste estudo gravando duas vezes as duas peças: antes e depois de conhecerem os dados básicos tais como título e compositor, as análises estruturais, as análises retóricas e as gravações dos pianistas mexicanos. Os dados extraídos das gravações foram analisados através de softwares especializados e revelaram semelhanças de variações de andamento na peça Noche (Adagio) com respeito à análise estrutural apresentada. Em referência à análise retórica não foram detectados traços comuns. Com respeito à peça Huarache: (Allegro pesante) não foram encontradas semelhanças na variação dos andamentos adotados. Os gráficos gerados das gravações dos pianistas brasileiros permitiram estabelecer a existência de semelhanças e diferenças no desempenho do andamento, como resultado da influência das informações disponibilizadas. Não foi possível estabelecer um padrão de comportamento do andamento baseado em semelhanças entre interpretações de pianistas mexicanos e brasileiros. / This work presents the analyses and comparison of three Mexican pianists’ recordings and six Brazilian pianists’ recordings of two pieces, Noche (No. 3) and Huarache (No. 4), from the eight movement Suite Carteles by Miguel Bernal Jiménez (México 1910- 1956). The analyses aimed at establishing both similarities and differences as a starting point for several performing possibilities based on findings of tempo and timing. The study evaluated the influence of the analyses and the listening of Mexican pianists’ recordings presented to the Brazilian pianists. Mexican pianists’ recordings were previously available to public access. The Brazilian pianists agreed voluntarily to participate in this study by recording the pieces twice: before and after receiving basic information such as title and composer, structural and rhetorical analysis as well as the recordings of Mexican pianists. The analyses of data extracted from recordings through specialized software showed similarities in tempo variations for the piece Noche (Adagio) in light of the structural analysis presented to the Brazilian participants. Rhetorical analyses presented to same group of participants did not seem to affect the results, there were no traceable differences. Results also point to a lack of discernible patterns for Huarache, the faster piece. Graphs generated from recordings by the Brazilian pianists show both similarities and differences in the timing and this can be attributed to the influences from analytical and recorded information. Finally, results point to wide differences in tempo, timing and overall understanding of the two groups.

No presente trabalho, as peças Noche (número 3) e Huarache (número 4) das oito que integram a Suíte Carteles de Miguel Bernal Jiménez (México: 1910-1956) serviram de base para analisar e comparar três gravações de pianistas mexicanos e seis gravações de três pianistas brasileiros. As gravações foram analisadas com relação ao andamento e suas micro flutuações (timing), visando os aspectos comuns e discrepâncias como ponto de partida das várias possibilidades interpretativas. Foi avaliada a influência das análises e das escutas de gravações dos pianistas mexicanos apresentadas aos pianistas brasileiros. As gravações dos pianistas mexicanos já estavam disponíveis publicamente. Os pianistas brasileiros concordaram voluntariamente em participar deste estudo gravando duas vezes as duas peças: antes e depois de conhecerem os dados básicos tais como título e compositor, as análises estruturais, as análises retóricas e as gravações dos pianistas mexicanos. Os dados extraídos das gravações foram analisados através de softwares especializados e revelaram semelhanças de variações de andamento na peça Noche (Adagio) com respeito à análise estrutural apresentada. Em referência à análise retórica não foram detectados traços comuns. Com respeito à peça Huarache: (Allegro pesante) não foram encontradas semelhanças na variação dos andamentos adotados. Os gráficos gerados das gravações dos pianistas brasileiros permitiram estabelecer a existência de semelhanças e diferenças no desempenho do andamento, como resultado da influência das informações disponibilizadas. Não foi possível estabelecer um padrão de comportamento do andamento baseado em semelhanças entre interpretações de pianistas mexicanos e brasileiros. / This work presents the analyses and comparison of three Mexican pianists’ recordings and six Brazilian pianists’ recordings of two pieces, Noche (No. 3) and Huarache (No. 4), from the eight movement Suite Carteles by Miguel Bernal Jiménez (México 1910- 1956). The analyses aimed at establishing both similarities and differences as a starting point for several performing possibilities based on findings of tempo and timing. The study evaluated the influence of the analyses and the listening of Mexican pianists’ recordings presented to the Brazilian pianists. Mexican pianists’ recordings were previously available to public access. The Brazilian pianists agreed voluntarily to participate in this study by recording the pieces twice: before and after receiving basic information such as title and composer, structural and rhetorical analysis as well as the recordings of Mexican pianists. The analyses of data extracted from recordings through specialized software showed similarities in tempo variations for the piece Noche (Adagio) in light of the structural analysis presented to the Brazilian participants. Rhetorical analyses presented to same group of participants did not seem to affect the results, there were no traceable differences. Results also point to a lack of discernible patterns for Huarache, the faster piece. Graphs generated from recordings by the Brazilian pianists show both similarities and differences in the timing and this can be attributed to the influences from analytical and recorded information. Finally, results point to wide differences in tempo, timing and overall understanding of the two groups.

No presente trabalho, as peças Noche (número 3) e Huarache (número 4) das oito que integram a Suíte Carteles de Miguel Bernal Jiménez (México: 1910-1956) serviram de base para analisar e comparar três gravações de pianistas mexicanos e seis gravações de três pianistas brasileiros. As gravações foram analisadas com relação ao andamento e suas micro flutuações (timing), visando os aspectos comuns e discrepâncias como ponto de partida das várias possibilidades interpretativas. Foi avaliada a influência das análises e das escutas de gravações dos pianistas mexicanos apresentadas aos pianistas brasileiros. As gravações dos pianistas mexicanos já estavam disponíveis publicamente. Os pianistas brasileiros concordaram voluntariamente em participar deste estudo gravando duas vezes as duas peças: antes e depois de conhecerem os dados básicos tais como título e compositor, as análises estruturais, as análises retóricas e as gravações dos pianistas mexicanos. Os dados extraídos das gravações foram analisados através de softwares especializados e revelaram semelhanças de variações de andamento na peça Noche (Adagio) com respeito à análise estrutural apresentada. Em referência à análise retórica não foram detectados traços comuns. Com respeito à peça Huarache: (Allegro pesante) não foram encontradas semelhanças na variação dos andamentos adotados. Os gráficos gerados das gravações dos pianistas brasileiros permitiram estabelecer a existência de semelhanças e diferenças no desempenho do andamento, como resultado da influência das informações disponibilizadas. Não foi possível estabelecer um padrão de comportamento do andamento baseado em semelhanças entre interpretações de pianistas mexicanos e brasileiros. / This work presents the analyses and comparison of three Mexican pianists’ recordings and six Brazilian pianists’ recordings of two pieces, Noche (No. 3) and Huarache (No. 4), from the eight movement Suite Carteles by Miguel Bernal Jiménez (México 1910- 1956). The analyses aimed at establishing both similarities and differences as a starting point for several performing possibilities based on findings of tempo and timing. The study evaluated the influence of the analyses and the listening of Mexican pianists’ recordings presented to the Brazilian pianists. Mexican pianists’ recordings were previously available to public access. The Brazilian pianists agreed voluntarily to participate in this study by recording the pieces twice: before and after receiving basic information such as title and composer, structural and rhetorical analysis as well as the recordings of Mexican pianists. The analyses of data extracted from recordings through specialized software showed similarities in tempo variations for the piece Noche (Adagio) in light of the structural analysis presented to the Brazilian participants. Rhetorical analyses presented to same group of participants did not seem to affect the results, there were no traceable differences. Results also point to a lack of discernible patterns for Huarache, the faster piece. Graphs generated from recordings by the Brazilian pianists show both similarities and differences in the timing and this can be attributed to the influences from analytical and recorded information. Finally, results point to wide differences in tempo, timing and overall understanding of the two groups.

In this dissertation, a systematic modeling study has been conducted to investigate the microwaveassisted magnetic recording (MAMR) and its related physics. Two different modeling approaches including effective field modeling and recording signal-to-noise ratio (SNR) modeling has been conducted to understand the MAMR mechanism on segmented thin film granular medium. First the background information about perpendicular magnetic recording (PMR) and its limitation has been introduced. The motivation of studying MAMR is to further improve the recording area density capacity (ADC) of the hard disk drive (HDD) and to overcome the theoretical limitation of PMR. The development of recording thin film medium has also been discussed especially the evolvement of the multilayer composite medium. Since the spin torque oscillator (STO) is the essential component in MAMR, different STO structures have been discussed. The relation between STO setting (thickness, location and frequency) to the ac field distribution has also been explored. In effective field modeling, both head configuration and medium structure optimization have been investigated. The head configuration study includes the effective field distribution in relation to the fieldgeneration- layer thickness, location, and frequency. Especially an interesting potential erasure is detected due to the imperfect circularity of the ac field. Several approaches have been proposed to prevent the erasure. Meanwhile, notched and graded segmentation structure have been compared through effective field analysis in terms of the field gradient and track width. It has been found that MAMR with notched Hk distribution is able to achieve both high field gradient and narrow track width simultaneously. In recording SNR modeling, first the behavior of MAMR with single layer medium has been studied and three phases have been discovered. As proceed to the multi-layer medium, a practical issue which is MAMR with insufficient ac field power and high medium damping has been introduced. Since the fabrication of STO with high ac power is highly difficult, the issue has been investigated from the medium side which is through an optimized medium structure, the provided ac field can be utilized more efficiently. It has been found that more segmentation on upper part of the grain to fit the ac field yields more efficient ac field power usage. Following this scenario, the graded and notched segmentation structure have been studied in terms of SNR and track width. The traditional dilemma between recording SNR and track width in the conventional PMR is partially solve using MAMR with notched segmentation structure.

This paper is about my investigation of early bluegrass recording techniques and the processes they used. After doing some extensive research, and compiling a database of black and white photographs from the time period, I felt I had enough information to assemble a team to try and produce the sounds, tonal qualities, and energy those recordings have. So John Kornhauser, Joshua Gooding, Hunter Berry, Sarah Griffin, along with myself, went to BigTone studios and tracked for two four hour sessions. BigTone studios has all of the vintage microphones, tape recorders, echo chambers, and out board equipment I need to replicate the same signal chain that was used on the early recordings. After the recording process, I mixed and mastered the songs to match the early recordings as closely as possible. We also recorded one song at ETSU’s studio that was all digital with new equipment to show the differences in the sound of analog versus digital recording. I have included both so that you can listen to each and determine for yourself if there is an audible difference, and if that difference is worth pursuing.