In the past decade, ultrashort laser sources have had a decisive impact on material processing for photonic applications. The technique is usually restricted to the elemental association of an ultrashort source with a focusing lens. It is thus limited in the achievable bulk modifications. Accompanying studies of material modifications in space and time, we propose here that automated spatio-temporal tailoring of the laser pulses is an efficient manner to overcome these limitations. More precisely, we demonstrate the generation of multiple processing foci for synchronous photomachining of multiple devices in the bulk. Thus, we report on the parallel photowriting of waveguides, light couplers, light dividers in 2D/3D in fused silica glass. We show that the domain of photowriting can be extended to deep focusing. We indicate that this can be achieved by wavefront shaping or temporal profile tailoring conducted by an evolutionary optimization loop. We also have unveiled a singular interaction regime where regular structuring takes place before the focal region. For the first time, the dynamics of the energy coupling to the glassy matrix is evaluated for various temporal pulse profiles. Enhanced energy confinement in the case of picosecond pulses is confirmed by characterization of the transient electronic gas and of the subsequent pressure. These pump-probe studies were carried out with a self-build time-resolved microscopy system with temporally shaped pump irradiation. We also developed a new method based on the Drude model to differentiate the electronic and matrix contributions to the contrast of the microscopy images.

International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / We explore the idea of matching a scaling function - the basic building block of a wavelet function - to a desired spectrum. This would allow the scaling function to be used as the signal pulse for a digital communication system that is matched to the channel, avoiding problems such as energy loss or noise amplification due to spectral nulls. An unconstrained parameterization of the scaling function coefficients represents the scaling functions. This parameterization is adapted using gradient descent. Tests indicate that the adaptation is able to capture major features of a desired spectrum, including spectral nulls and major lobes.

Future NASA plans to launch large space strucutres solicit the need for effective vibration control schemes which can solve the unique problems associated with unwanted residual vibration in flexible spacecraft. In this work, a unique method of input command shaping called impulse shaping is examined. A theoretical background is presented along with some insight into the methdos of calculating multiple mode sequences. The Middeck Active Control Experiment (MACE) is then described as the testbed for hardware experiments. These results are shown and some of the difficulties of dealing with nonlinearities are discussed. The paper is concluded with some conclusions about calculating and implementing impulse shaping in complex nonlinear systems.

Input shaping and Proportional-Integral-Derivative (PID) feedback control are simple, easy-to-implement and generally low cost control strategies. Considering this, it is remarkable that they are also very effective control techniques. In fact, a majority of the world's feedback controllers utilize PID (or the subset PD) control. In addition, input shaping has seen significant use on real-world machines such as cranes, micro-mills, coordinate measuring machines, computer disc drive manufacturing machines, spacecraft, etc. However, despite similarities in effectiveness and ease of implementation, input shaping and PID feedback control are fundamentally different strategies. Input shaping is an anticipatory control scheme capable of enabling quick, low-vibration motions. PID feedback control is reactive in nature, and it is primarily required to deal with problems such as modeling errors, disturbances and nonlinearities. Of course, PID control is also used to reduce vibrations (as in the case of input shaping). But, because it is a reactive controller, it is slower than input shaping at eliminating motion-induced vibration. Given their effectiveness and practicality, as well as the fact that they address important and complimentary control issues, it would be advantageous to combine these two control strategies. The result would still be practical and effective, yet would now address a range of system phenomenon beyond that which is capable by either of the individual control techniques. However, there is a definite gap in the state-of-the-art technology for combining these techniques. For example, little research has addressed the intelligent combination of traditional, outside-the-loop input shaping and PID feedback control. In addition, only a few researchers have attempted to place input shaping filters within feedback loops. This research studies the intelligent combination of input shaping and PID feedback control by developing a concurrent design procedure for outside-the-loop input shaping/PID feedback combinations and by analyzing the effect of placing input shaping filters within feedback loops.

The present experiment compared two methods of training a simple arm position using auditory feedback: capture and search. The participants were four right-handed female college students. During capture, auditory feedback was delivered by the experimenter after the participant moved along a single axis into the target position. During search, auditory feedback was produced by the computer after the participant left clicked a mouse inside the target location. The results of a multi-element design showed that participants performed more accurately during capture training than search training. Pre-training and post-training probes, during which no auditory feedback was provided, showed similar fluctuations in accuracy across probe types. A retention check, performed seven days after the final training session, showed higher accuracy scores for search than capture, across all four participants. These findings suggest that TAGteach should incorporate an approach similar to search training to improve training outcomes.

Of the approximately 3.9 million dogs that enter US animal shelters each year, many exhibit behaviors related to fear, which can affect their likelihood of adoption. Current dog training procedures to treat fear include counterconditioning and desensitization, which can often take months or years to show any behavior change and do not teach specific behaviors aimed to increase the dog's chance of being adopted. The current study used a negative reinforcement shaping procedure to teach fearful dogs to approach and and interact with people. The results showed that constructional fear treatment increased the amount of time the dog spent at the front of the kennel, and increased sniffing, tail wagging, and accepting petting for all 3 participants.

This thesis focuses on the evolution of the Internet system. It examines the dynamics of competing and collaborating technologies in the invention and development of computer networking technologies in general. In particular, it examines the negotiations among social groups with different economic and political interests in designing the Internet system. This system has been shaped by competition and collaboration between the US and other countries (other regions) reflecting their different institutional arrangements in the telecommunications sector and the dynamics of uneven power relationships. Population dynamics, i.e. similarities and differences in the growth and pervasiveness of the Internet system between regions and countries, are also examined to uncover how the co-evolution between technological system and social, cultural, and economic systems countries influenced by global and local interplay. This thesis combines techno-economic and socio-technological approaches in technology studies to address the 'localisation' of a technological system, how a system adapted to or was influenced by the local context of its application. This research focuses on empirical evidence about the evolution of the Internet system, recognizing that the Internet system is one instance of a large technological system. In addition, the political economy perspective provides a foundation for an integrated analysis of the local situation and the wider power structure which illustrates the economic and political interests that are embedded in the design and development of the Internet system. The main research questions are how have political and economic interests shaped the evolution of the Internet system and why does the outcome of the Internet system's development vary across countries? The Internet system emerged from one of the early experimental computer networks in the US, the UK and France during the development of packet switching technology and it involved mainly computer scientists. The development of packet switching technologies has been shaped by battles for control between network operators and computer manufacturers as a consequence of technological convergence; and between telecommunication operators and advanced users (e.g. computer engineers and scientists in the case of the Internet system) in the process of institutional change in telecommunications sector. The analysis shows how these battles were guided by different interests and strategies between, notably, the US and European countries. The analysis of the population dynamics of Internet system development confirms its uneven development between countries following regional, economic and cultural routes. It also confirms that the international spread of the Internet network is influenced by different choices of ICTs and non-linear relationships between competing technologies. The sources of uneven development of the Internet system are founded in the global expansion of the Internet system. These sources are shown to include: asymmetric development of research networks between regions and countries, the effects of the different economic and political interests of the US (and European countries) in connecting the Internet to other countries and regions, the US-centered network design and the international financial settlement regime for the Internet in addition to the existing technological and economic gaps and cultural differences between countries that influence the localisation of the Internet system. The empirical findings that emerge from the econometric modelling demonstrate that knowledge production and distribution capabilities, global integration efforts, economic strength and equality of income distribution, size of social system, telecommunication policies, science and technology policies, prices for access and using of the Internet, all influence the localisation of the Internet system. The thesis contests many accounts of the diffusion of the Internet that are based on 'technological inevitability' and the 'universality' of the technical methods chosen.

As the rapid evolution in semiconductor technology, transistors’ feature size has reached to 22nm and below, which brings great impact to analog and mixed-signal circuits. As the significant bridge connecting the analog world and digital system, data converter suffers from nonlinearity resulting from mismatch among its unit components. The smaller transistors are, the larger relative mismatch among them becomes. However, using larger transistors leads to more area cost and power consumption. Therefore, researchers have been working hard on how to alleviate the mismatch issue. In recent years, Dynamic Element Matching (DEM) becomes a popular approach that can significantly improve linearity, especially Spurious-free Dynamic Range (SFDR), of a data converter system. The basic idea of DEM is to shuffle the usage pattern of unit elements so that the mismatch error is no longer correlated to the input signal. Thus, DAC’s linearity will be improved. Generally, DEM Nyquist-rate DAC does mismatch scrambling, which smooths distortions resulting from mismatch into white noise. DEM Delta-Sigma DAC does mismatch shaping, which pushes distortions away from the signal band, typically lower frequencies. In this thesis, we focused on mismatch-shaping Delta-Sigma DACs. Two of those various algorithms are implemented logically and physically. With placement and routing information, we got more accurate result on the speed and power dissipation. The comparison shows the tradeoff among number of quantization levels, mismatch-shaping order, and hardware complexity. / text

When light encounters scattering materials such as biological tissue, white paint or clouds, it gets randomly scattered in all directions, which traditionally has been seen as a barrier for imaging techniques (reducing their resolution) or sensing, due to the reduction of the penetration depth of light. However, in recent years it has been shown that scattering might not necessarily be an impediment, and that the knowledge of the properties of multiple scattering can be indeed useful for imaging, sensing and other applications. In the first part of this thesis (Chapters 2 to 5) we study the implications of manipulating the light incident on a multiply scattering material. We experimentally show how by actively controlling the output light of a bad quality laser we manage to not only improve its beam quality, but also in an energy-efficient way, in comparison with traditional methods. In a different experiment presented in this thesis, we show how the active control of the light incident on a scattering material can be useful to improve sensing through scattering media, by means of increasing the transmission and energy deposited inside (Chapter 5). In the final part of the thesis we present the first experimental observation of intensity correla- tions between transmitted and reflected patterns from a scattering material (Chapter 6), exploring how it depends on the parameters of the scattering medium. In the last part of the thesis (Chapter 7) we present a new imaging technique based on the use of the intensity correlations described in the previous chapter, opening new possibilities to non-invasive imaging through highly scattering materials.

Residual vibrations degrade the performance of many systems. Due to the lightweight and flexible nature of space structures, controlling residual vibrations is especially difficult. Also, systems such as the Space Shuttle remote Manipulator System have frequencies that vary significantly based upon configuration and loading. Recently, a technique of minimizing vibrations in flexible structures by command input shaping was developed. This document presents research completed in developing a simple, closed- form method of calculating input shaping sequences for two-mode systems and a system to adapt the command input shaping technique to known changes in system frequency about the workspace. The new techniques were tested on a three-link, flexible manipulator.