Improved cochlear implant (CI) designs and surgical techniques have allowed CI patients to retain acoustic hearing in the implanted ear post-operatively. These EAS (electric-acoustic stimulation) CI users listen with a combination of acoustic and electric hearing in the same ear. While electric hearing alone improves speech recognition in quiet, preserved acoustic hearing allows EAS CI users to outperform traditional CI users in speech recognition in noise and demonstrate “speech masking release,” an improvement in speech recognition in temporally fluctuating noise relative to steady noise. Masking release is arguably an ecologically valid metric, as listeners often attend to target speech embedded in fluctuating competing speech. Improved speech recognition outcomes have been attributed to the spectral and temporal resolution provided by acoustic hearing. However, the relationship between spectral and temporal resolution and outcomes in EAS CI users is not clear. This study evaluated speech masking release, spectral ripple density discrimination thresholds, and fundamental frequency difference limens (f0DLs) in EAS CI users. Both the ripple and f0DL tasks are thought to measure underlying spectral resolution and temporal fine structure. EAS CI subjects underwent testing in three listening modes: acoustic-only, electric-only, and acoustic+electric. Comparisons across listening modes allowed the benefit provided by acoustic hearing to be quantified. It was hypothesized that speech masking release, spectral ripple density discrimination thresholds, and f0DLs would be poorest with electric-only hearing and would improve in the acoustic-only and acoustic+electric listening modes. This would reflect the benefit of preserved acoustic hearing. It was also hypothesized that speech masking release would correlate with spectral ripple density discrimination thresholds and f0DLs, reflecting the roles of spectral and temporal fine structure cues. Lastly, it was hypothesized that EAS CI users with more residual hearing (lower audiometric thresholds) would perform better on all three tasks. Speech masking release was evaluated using a 12-alternative-forced-choice (AFC) spondee recognition in noise task. The noise was a two-talker and a ten-talker babble presented at -5 dB SNR, and masking release was quantified as the difference in spondee recognition in two-talker babble relative to ten-talker babble. Spectral ripple density discrimination thresholds were assessed in a 3-AFC task using a broadband stimulus that contained spectral peaks and valleys logarithmically spaced on the frequency axis. The spacing between spectral peaks (ripple density) was varied to determine the threshold at which listeners could no longer resolve the individual spectral peaks. F0DLs were assessed via a 3-AFC task using a broadband harmonic complex with a baseline f0 = 110 Hz. The f0 of the test intervals was varied to determine the smallest change in f0 that the listener could detect. Results showed that performance in all three measures was poorest when EAS CI users were tested using electric-hearing only, with significant improvements when tested in the acoustic-only and acoustic+electric listening modes. F0DLs, but not spectral ripple density discrimination thresholds or audiometric thresholds, significantly correlated with speech masking release. Speech masking release also significantly correlated with open-set AzBio sentence recognition in noise scores obtained from clinical records. Results indicated that preservation of residual acoustic hearing allows for speech masking release, likely due to access to temporal fine structure cues provided by residual hearing. The significant correlation between speech masking release and sentence recognition in noise indicates that the ability to extract target speech embedded in temporally fluctuating competing speech is important for speech recognition in noise. Funded by National Institutes of Health/National Institutes on Deafness and Other Communication Disorders (NIH/NIDCD) P50 DC000242, American Speech-Language-Hearing Foundation Student Research Grant, and American Academy of Audiology Student Investigator Research Grant.

<p>Fast addition is essential in many DSP algorithms. Various structures have been introduced to speed up the time critical carry propagation. For high throughput applications, however, it may be necessary to introduce pipelining. In this report the power consumption of four different adder structures, with varying word length and different number of pipeline cuts, is compared. </p><p>Out of the four adder structures compared, the Kogge-Stone parallel prefix adder proves to be the best choice most of the time. The Brent-Kung parallel prefix adder is also a good choice, but the maximal throughput does not reach as high as the maximal throughput of the Kogge-Stone parallel prefix adder.</p>

In der Arbeit wird das Reibungsverhalten an Polymerbürsten im nanoskopischen und makroskopischen Kontakt beschrieben. Besonderes Augenmerk liegt auf den durch Reibung hervorgerufenen Deformationen.

Uno de los campos más importantes de la Electrónica de Potencia es el de los convertidores de potencia conmutados, que debido a sus características de alto rendimiento energético, reducido tamaño, posibilidades de regulación del factor de potencia y de elevación de tensión, etc., están presentes en un gran número de las etapas de alimentación de los equipos electrónicos actuales.Las mejoras tecnológicas en ámbitos como el de la integración de circuitos han permitido importantes reducciones en el tamaño de los equipos (por ejemplo en los ordenadores). Sin embargo, este proceso de reducción de tamaño que, además, suele venir unido a unas especificaciones más rígidas en cuanto a costes, rendimiento, seguridad y prestaciones en general, no se ha producido en igual medida en las etapas de alimentación. El estudio de los convertidores conmutados es por lo tanto un campo necesitado de esfuerzos de investigación y desarrollo.Para potencias superiores a 25 W, y especialmente en potencias superiores a 150 W, una de las estrategias utilizadas para mejorar las prestaciones de los convertidores es el uso del denominado "interleaving" o entrelazado , definido como la puesta en paralelo de N convertidores idénticos desfasando sus señales de control de forma uniforme a lo largo del periodo de conmutación.Con el objetivo principal de reducir al máximo los rizados de la tensión de salida y de la corriente de entrada, en esta tesis se estudian casos particulares de "interleaving" en estructuras convertidoras continua-continua que utilizan el convertidor elevador ("boost") como célula básica y cuyas tensiones de salida son, idealmente y operando en modo de conducción continua, múltiplos enteros positivos de la tensión de entrada, de ahí la denominación de multiplicadores de tensión que aparece en el título de tesis propuesto. Posteriormente se analizan las posibilidades de regulación de tensión que presentan algunos de los casos de estudio, a costa de incrementar los rizados.

Fast addition is essential in many DSP algorithms. Various structures have been introduced to speed up the time critical carry propagation. For high throughput applications, however, it may be necessary to introduce pipelining. In this report the power consumption of four different adder structures, with varying word length and different number of pipeline cuts, is compared. Out of the four adder structures compared, the Kogge-Stone parallel prefix adder proves to be the best choice most of the time. The Brent-Kung parallel prefix adder is also a good choice, but the maximal throughput does not reach as high as the maximal throughput of the Kogge-Stone parallel prefix adder.

Power management components can be found in a host of different applications ranging from portable hand held gadgets to modern avionics to advanced medical instrumentations, among many other applications. Low-dropout (LDO) linear regulators are particularly popular owing to their: ease of use, low cost, high accuracy, low noise, and high bandwidth. With all its glory, however, it tends to underperform switched-mode power supplies (SMPS) when with comes to power conversion efficiency, although the later generates a lot of ripple at its output. With the growing need to improve system efficiency (hence longer battery life) without degrading system performance, many high end (noise sensitive) applications such as data converters, RF transceivers, precision signal conditioning, among others, use high efficiency SMPS with LDO regulators as post-regulators for rejecting the ripple generated by SMPS. This attribute of LDO regulators is known as power supply rejection (PSR). With the trend towards increasing switching frequency for SMPS, to minimize PC board real estate, it is becoming ever more difficult for LDO regulators to suppress the associate high frequency ripple since at such high frequencies, different parasitic components of the LDO regulator start to deteriorate its PSR performance. There have been a handful of different techniques suggested in the literature that can be used to achieve good PSR performance at higher frequencies. However, each of these techniques suffers from a number of drawbacks ranging from reduced efficiency to increased cost to increased solution size, and with the growing demand for higher efficiency and smaller power supplies, these techniques have their clear limitations. The objective of this research project is to develop a novel current-mode LDO regulator that can achieve good high frequency PSR performance without suffering from the afore mentioned drawbacks. The proposed architecture was fabricated using a proprietary 1.5 um Bipolar process technology, and the measurement results show a PSR improvement of 20dB (at high frequencies) over conventional regulators. Moreover, the proposed LDO regulator requires a small 15nF output capacitor for stability, which is far smaller than some of the currently used techniques.

Workflow Management Systems (WfMSs) are used to support the modelling, analysis, and enactment of business processes. The key benefits WfMSs seek to bring to an organisation include improved efficiency, better process control and improved customer service, which are realised by modelling rigidly structured business processes that in turn derive well-defined workflow process instances. However, the proprietary process definition frameworks imposed by WfMSs make it difficult to support (i) dynamic evolution and adaptation (i.e. modifying process definitions during execution) following unexpected or developmental change in the business processes being modelled; and (ii) exceptions, or deviations from the prescribed process model at runtime, even though it has been shown that such deviations are a common occurrence for almost all processes. These limitations imply that a large subset of business processes do not easily translate to the 'system-centric' modelling frameworks imposed. This research re-examines the fundamental theoretical principles that underpin workflow technologies to derive an approach that moves forward from the productionline paradigm and thereby offers workflow management support for a wider range of work environments. It develops a sound theoretical foundation based on Activity Theory to deliver an implementation of an approach for dynamic and extensible flexibility, evolution and exception handling in workflows, based not on proprietary frameworks, but on accepted ideas of how people actually perform their work activities. The approach produces a framework called worklets to provide an extensible repertoire of self-contained selection and exception-handling processes, coupled with an extensible ripple-down rule set. Using a Service-Oriented Architecture (SOA), a selection service provides workflow flexibility and adaptation by allowing the substitution of a task at runtime with a sub-process, dynamically selected from its repertoire depending on the context of the particular work instance. Additionally, an exceptionhandling service uses the same repertoire and rule set framework to provide targeted and multi-functional exception-handling processes, which may be dynamically invoked at the task, case or specification level, depending on the context of the work instance and the type of exception that has occurred. Seven different types of exception can be handled by the service. Both expected and unexpected exceptions are catered for in real time. The work is formalised through a series of Coloured Petri Nets and validated using two exemplary studies: one involving a structured business environment and the other a more creative setting. It has been deployed as a discrete service for the well-known, open-source workflow environment YAWL, and, having a service orientation, its applicability is in no way limited to that environment, but may be regarded as a case study in service-oriented computing whereby dynamic flexibility and exception handling for workflows, orthogonal to the underlying workflow language, is provided. Also, being open-source, it is freely available for use and extension.

This master thesis explores how blockchain technologies can be utilized within the financial sector with focus on how to store both private and public information on the blockchain. The capital market is looking into ways of cutting down administrative work through streamlining the financial process by using blockchain technologies. Public key encryption together with hash functions and a consensus mechanism make up the basis for creating a shared trustless database system. The thesis was conducted by extensive research concerning cryptographic topics, and a literature study was made to compare existing solutions. This was done in order to come up with a new design which suggests how to utilize blockchain technologies in order to create private transactions. The design solves issues regarding key management and how to handle both private and public information on the blockchain. The proposed design is an extension of Visigon's existing permissioned blockchain, and it introduces different roles within the peer to peer network as well as a concept of having regulating nodes that together with the involved bank's nodes handle the process of private transactions. Private transactions are encrypted by using symmetric keys and thereafter recorded on the blockchain. In conclusion blockchain technology might not be the most suitable database system for banks to keep transactions private. Future solutions should consider the best attributes of blockchain technologies and create a new system with the single purpose of being a tool for the financial market.

This thesis describes important existing cryptocurrencies and their basis principles. Especially it describes differences between this cryptocurrencies and theid basis principles. Also describes posibilites for analysis of Bitcoin blockchain. Next part describes improvments of tool for blockchain analysis. Futher it describes cryptocurrency analyzing tool, and it's implemented extensions.

This diploma thesis deals with elektrical power quality in DC grids. Electrical power is commodity and therefore it must be represented not just with quantitative, but also with qualitative parameters. Nowadays, there is an increasing demand for bigger implementation of renewable energy sources and more efficient power systems, which motivates installation of DC grids. However, development of DC grids is decelerated by lack of standardization alson in power quality. The work includes definition of power quality parameters and their measurement methodology.