As technology has scaled into nanometer regime, manufacturing variations have emerged as a major limiter of performance (timing) in VLSI circuits. Issues related to timing are addressed in the first part of the dissertation. Statistical Static Timing Analysis (SSTA) has been proposed to perform full-chip analysis of timing under uncertainty such as manufacturing variations. In this dissertation, we propose an efficient sparse-matrix framework for a path-based SSTA. In addition to an efficient framework for doing timing analysis, to improve the accuracy of the timing analysis one needs to address the accuracy of: waveform modeling, and gate delay modeling. We propose a technique based on Singular Value Decomposition (SVD) that accurately models the waveform in a timing analyzer. To improve the gate delay modeling, we propose a closed form expression based on the centroid of power dissipation. This new metric is inspired by our key observation that the Sakurai-Newton (SN) delay metric can be viewed as the centroid of current. In addition to accurately analyzing the timing of a chip, improving timing is another major concern. One way to improve timing is to scale down the threshold voltage (Vth). But scaling down increases the subthreshold leakage current exponentially. Sleep transistors have been proposed to reduce leakage current while maintaining performance. We propose a path-based algorithm to size the sleep transistor to reduce leakage while maintaining the required performance. In the second part of dissertation we address power grid and thermal issues that arise due to the scaling of integrated circuits. In the case of power grid simulation, we propose fast and efficient techniques to analyze the power grid with accurate modeling of the transistor network. The transistor is modeled as a switch in series with an RC and the switch itself is modeled behaviorally. This model allows more accurate prediction of voltage drop compared to the current source model. In the case of thermal simulation, we address the issue of ignoring the nonlinearity of thermal conductivity in silicon. We found that ignoring the nonlinearity of thermal conductivity may lead to a temperature profile that is off by 10° C.

Abstract In recent years, the amount of electronic communication has grown enormously. This has posed some new problems in information security. In particular, the methods in cryptography have been under much scrutiny. There are several basic primitives that modern cryptographic protocols utilise. One of these is hash functions, which are used to compute short hash values from messages of any length. In this thesis, we study the security of hash functions from two different viewpoints. First of all, we analyse the security of the Very Smooth Hash against preimage attacks. We develop an improved method for finding preimages of Very Smooth Hash, compare this method with existing methods and demonstrate its efficiency with practical results. Furthermore, we generalise this method to the discrete logarithm variants of the Very Smooth Hash. Secondly, we describe the methods for finding multicollisions in traditional iterated hash functions and give some extensions and improvements to these. We also outline a method for finding multicollisions for generalised iterated hash functions and discuss the implications of these findings. In addition, we generalise these multicollision finding methods to some graph-based hash functions. / Tiivistelmä Viime vuosina digitaaliseen tiedonsiirtoon perustuva tiedonsiirto on yleistynyt valtavasti. Tästä on seurannut monia uusia tietoturvaongelmia. Tässä yhteydessä erityisesti tiedon suojaamiseen käytetyt kryptografiset menetelmät ovat olleet tarkastelun kohteena. Hash-funktiot ovat yksi käytetyimmistä työkaluista nykyisissä kryptografisissa protokollissa. Tässä väitöskirjassa tarkastellaan hash-funktioiden turvallisuutta kahden eri tutkimusongelman kautta. Aluksi tutkitaan Very Smooth Hash -funktion turvallisuutta alkukuvien löytämistä vastaan. Alkukuvien löytämiseksi esitetään parannettu menetelmä, jota arvioidaan teoreettisilla ja käytännöllisillä menetelmillä. Tämä parannettu menetelmä yleistetään koskemaan myös Very Smooth Hashin muunnoksia, jotka perustuvat diskreetin logaritmin ongelmaan. Toisena tutkimuskohteena ovat iteroitujen hash-funktioiden yleistykset ja monitörmäykset. Aluksi esitellään perinteisiin iteroituihin hash-funktioihin liittyviä monitörmäysmenetelmiä. Tämän jälkeen tutkitaan iteroitujen hash-funktioiden yleistyksiä ja osoitetaan, että aiemmat monitörmäysmenetelmät voidaan laajentaa koskemaan myös näitä yleistyksiä. Lopuksi tutkitaan graafeihin perustuviin hash-funktioihin liittyviä monitörmäysmenetelmiä ja osoitetaan, että iteroitujen hash-funktioiden monitörmäysmenetelmä voidaan osittain yleistää koskemaan myös graafeihin perustuvia hash-funktioita.

Of the challenges facing the improvement of human health, none has taken the forefront quite like the endeavor to discover novel treatments for heart disease. As heart disease has now become the leading cause of death throughout the world [1], the medical community has made incredible strides in the mission to treat atherosclerosis which is the major contributor to heart disease. Very Low Density Lipoproteins (VLDL) are secreted by the liver and subsequently converted to Low Density Lipoproteins (LDL). Many factors contribute to the narrowing of the arterial walls, however oxidized LDL is the main factor that leads to the deposition of plaque, leading to atherosclerosis pathologies. Recently, a main focus of research into atherosclerotic processes has been the synthesis and trafficking of VLDL in hepatocytes. The rate-limiting step for the secretion of VLDL from the liver has been determined to be the transport of VLDL from the endoplasmic reticulum (ER) to the Golgi apparatus. VLDL molecules are transported in a specialized transport vesicle the Very Low Density Lipoprotein Transport Vesicle (VTV) [2]. VLDL’s core protein, apolipoproteinB-100 (apoB100), is initially lipidated in the ER, and then subsequently delivered to the Golgi apparatus where the VLDL molecule undergoes maturation involving further lipidation and glycosylation of apoB100. Oxysterol Binding Proteins (OSBP) and the sub family OSBP Related Proteins (ORP) have been implicated in many different trafficking processes, mainly the trafficking of sterols, cholesterol, and lipids. Recently, ORP 10 was shown to be a negative regulator of apoB100 secretion in growth medium [3]. Using co-immunoprecipitation, the current study shows that ORP 10 interacts with VLDL’s core protein apoB100 directly. Employing an in vitro budding assay, we show that the blocking of ORP 10 with a specific antibody against ORP10 increases VTV formation from the ER. Given that the ER to Golgi pathway is the rate-limiting step in overall VLDL secretion, these findings support the conclusion that ORP 10 is a negative regulator of VLDL trafficking between the ER and Golgi, and that this process is mediated by the ORP 10 protein binding with apoB100.

One of the most important electrical requirements in high performance electronic systems or high speed integrated circuits, is to process larger numbers of electrical signals at much higher speeds. Signal propagation delay must be minimized in order to maximize signal velocities. Therefore, material with low dielectric constant and low dissipation factor is being sought. In this thesis research measurements of dielectric constant and dissipation factor were performed on commercially available polyimides that are used in multilayer interconnect structures. Capacitor structures with a polyimide dielectric were measured up to a 1GHz frequency and 220°C temperature. Polyimides were concluded to be compatible for use in high performance systems such as multilayer interconnect structures.

Urinvägsinfektioner är den näst vanligaste anledningen till antibiotikaförskrivning i Sverige. För diagnos av UVI i urinkultur med standardmetoden krävs 18 - 48 timmar och ytterligare 24 timmar i odling tills resultaten för antimikrobiell känslighetstestning är tillgängliga. Direktresistensmetoden ger svar 24 timmar tidigare än standardmetoden. Studiens syfte var att utvärdera direktresistensmetoden (in-housemetod) från mikrobiologiska laboratoriet Unilabs, Skövde på urinodlingar från patientprover och jämföra den med EUCAST-diskdiffusionsmetod. I denna studie användes 334 bakteriestammar från urinodlingar; E. coli (n=211) E. faecalis (n=45), Klebsiella spp (n=37), P. mirabilis (n= 17) och övriga gramnegativa bakteriestammar (n=24). Direktresistensmetoden och EUCAST diskdiffusionsmetod har utförts parallellt på alla bakteriestammar och sex olika antibiotikatyper testades. Hämningszonernas diameter lästes av och placerades i rätt S, I, R kategori för respektive antibiotikum. Från sammanlagt 1674 testade antibiotikalappar hittades 23 avvikelser där E. coli representerade 13 av dessa. Mecillinam var det antibiotikum där flest avvikelser noterades, totalt tio stycken. Överensstämmelsen mellan de två metoderna var 98,6% från 1674 testade antibiotikalappar. Direktresistensmetoden leder till att patienten få ett svar 24 timmar tidigare än med EUCAST diskdiffusionsmetoden där svaret inkluderar även resistensbestämning. / Urinary tract infections are the second most common reason for prescription of antibiotics in Sweden. Diagnosis of UTIs in urine culture by the standard method requires 18 to 48 hours and an additional 24 hours until antimicrobial testing is available. The direct resistance method provides answers 24 hours earlier than the standard method. The aim of the study was to evaluate the direct resistance method (in-house method) from the microbiological laboratory Unilabs, Skövde on urine cultures from patient samples and compare it with the EUCAST disc diffusion method. For this study, 334 bacterial strains from urinary cultures were used; E. coli (n = 211) E. faecalis (n = 45), Klebsiella spp (n = 37), P. mirabilis (n = 17) and other gram-negative rods (n = 24). The direct resistance method and the EUCAST disk diffusion method were performed in parallel on all bacterial strains and six different types of antibiotics were tested. The diameter of the inhibition zones was measured and categorized according to S, I, R for each antibiotic. From a total of 1674 tested antibiotics 23 discrepancies were found where E. coli represented 13 of these. Mecillinam was the antibiotic where most discrepancies were noted, a total of ten. The agreement between the two methods was 98,6% from 1674 tested antibiotics. The direct resistance method allows a response to the patient 24 hours earlier than the EUCAST disc diffusion method.

Bibliography: leaves 249-260.

A new formalism is presented for calculating the mean intensity spectrum and angular power spectrum of gamma-rays or neutrinos from extragalactic annihilating dark matter, taking into account the dependence of the relative motions of the annihilating particles on the annihilation cross section. To model the large scale dark matter distribution of mass and relative velocities, the halo distribution model is comprehensively summarized, and extended to include a universal radial profile of the particles' velocity variance, based on results from N-body computer simulations of dark matter halos. A velocity variance profile, associated with the NFW density profile, is proposed by enforcing a power-law profile of the pseudo phase-space density. This allows the large-scale velocity distribution to be described by virialized, gravitationally bound dark matter halos, as opposed to thermal motions used to describe the velocity distribution in the early Universe. The recent particle motion history of the Universe is presented for the described model. Sample extragalactic gamma-ray intensities from dark matter annihilation are shown for dark matter annihilating with p-wave, according to a relative-velocity-weighted annihilation cross section sigmav = a + bv^2, for constants a and b, with examples taken from supersymmetric models. For thermally produced dark matter, the p-wave suppresses the signal intensity. If b/a > 10^6, the p-wave hardens the intensity spectrum by an estimated factor of 1 + (6b/a)delta_I (E_gamma), and increases the angular power spectrum by a factor also depending on new coefficients (delta_Cl)^(1) (E_gamma ) and (delta_Cl)^(2) (E_gamma ). The energy-dependence of the new p-wave coefficients delta_I , (delta_Cl)^(1) (E_gamma ), and (delta_Cl)^(2) (E_gamma ) are shown for various annihilation spectra. Sample intensity spectra are also presented for Sommerfeld-enhanced annihilation. The intensity of neutrinos from dark matter annihilation is also considered. The variations between the dark matter annihilation signals for different particle phenomenologies suggest that particle physics constraints are possible from an observed indirect detection signal. Calculations of the annihilation signal from the galactic halo are also shown. The extragalactic signal's intensity is found to be consistent in magnitude with the galactic intensity?within the uncertainty of the models of the dark matter distribution?when looking out from the galactic plane. This suggests that the total cosmic signal may have significant contributions from both components.

In all of the previous pipelining methods such as conventional pipelining, wave pipelining, and mesochronous pipelining, a data wave propagating on the combinational circuit is sampled whenever it arrives to a synchronization stage. In this study, a new wave-pipelining methodology named as Wave Component Sampling Method (WCSM), is proposed. In this method, only the component of a wave, whose maximum and minimum delay difference exceeds the tolerable value, is sampled, and the other components continue to propagate on the circuit. Therefore, the total number of registers required for synchronization decreases significantly. For demonstrating the effectiveness of the proposed WCSM, an 8x8 bit carry save In all of the previous pipelining methods such as conventional pipelining, wave pipelining, and mesochronous pipelining, a data wave propagating on the combinational circuit is sampled whenever it arrives to a synchronization stage. In this study, a new wave-pipelining methodology named as Wave Component Sampling Method (WCSM), is proposed. In this method, only the component of a wave, whose maximum and minimum delay difference exceeds the tolerable value, is sampled, and the other components continue to propagate on the circuit. Therefore, the total number of registers required for synchronization decreases significantly. For demonstrating the effectiveness of the proposed WCSM, an 8x8 bit carry save adder (CSA) multiplier is implemented using 0.18&micro / m CMOS technology. A generic transmission gate logic block with optimized output delay variation depending on the input pattern is designed and used in all of the sub blocks of the multiplier. Post layout simulation results show that, this multiplier can operate at a speed of 3GHz, using only 70 latches. Comparing with the mesochronous pipelining scheme, the number of the registers is decreased by 41% and the total power of the chip is also decreased by 9.5% without any performance loss. An ultra high speed full pipelined CSA multiplier with an operating frequency of 5GHz is also implemented with WCSM. The number of registers is decreased by 45%, and the power consumption of the circuit is decreased by 18.4% comparing with conventional or mesochronous pipelining methods. WCSM is also applied to different multiplier structures employing booth encoders, Wallace trees, and carry look-ahead adders. Comparing full pipelined 8x8 bit WCSM multiplier with the conventional pipelined multiplier, the number of registers in the implementation of booth encoder, Wallace tree, and carry look-ahead adder is decreased by 30%, 51%, and %62, respectively.

No description available.

Made available in DSpace on 2016-03-15T19:37:41Z (GMT). No. of bitstreams: 1 Jorge Enrifque Samanes Cardenas.pdf: 3561395 bytes, checksum: ba28ce6fbd3bd0e1573255ccacb30d17 (MD5) Previous issue date: 2012-02-17 / Fundo Mackenzie de Pesquisa / Deep amplitude minima are observed in the daily records of Very Low Frequency (VLF, between 3 - 30 kHz) wave amplitudes. Amplitude minima are attributed to modal interference and modal conversion of waves propagating in the Earth - Ionosphere waveguide. The time of amplitude minima is related with the localization of the Terminator line and, therefore, is denominated of Terminator Time or TT time. In this work, we developed a methodology based on the monitoring of TT time to infer the distance of modal interference D and its temporal variation in relation to atmospheric and natural phenomena. For this purpose, we used data provided by the South America VLF Network (SAVNET) to the period 2007 - 2011. The results showed that the methodology is a promising tool to study the dynamics of the lower ionosphere, by means of the daily values of the undisturbed nighttime ionospheric height(hN). We identified short-term and long-term time variations of hN, where the long-term variation is possibly related with the solar activity cycle. We propose the use of this method to search for seismic- electromagnetic effects, and that it should be applied to medium and short propagation paths. Using the Long Wave Propagation Capability (LWPC) code, we simulated TT times and the results show good agreement with the observations, so a value for nighttime height hN = 88 km is suggested. This work will contribute to a greater viability of the use of the VLF technique for the study of the lower ionosphere and the forcings acting on this region of the atmosphere. / Pronunciados mínimos de amplitude são observados nos registros diários de sinais de muito baixa frequência ou VLF (do inglês Very Low Frequency, entre 3 - 30 kHz). A presença destes mínimos é atribuída a interferência e conversão modal de ondas se propagando no guia de onda Terra - Ionosfera. Os tempos de ocorrência destes mínimos são relacionados com a localização do Terminadouro e, por isso, são denominados de tempos de Terminadouro ou Tempos TT. Neste trabalho, desenvolvemos uma metodologia baseada no monitoramento dos tempos TT para inferir a distância de interferência modal D, e sua variabilidade temporal em relação a fenômenos atmosféricos e naturais. Para isso, utilizamos dados fornecidos pela rede SAVNET (South America VLF Network) durante o período 2007 - 2011. Os resultados mostraram que a metodologia é relevante para estudar a dinâmica da baixa ionosfera, através da obtenção de valores diários da altura noturna hN. Identificamos variabilidades de curto e longo período para hN, sendo estas últimas relacionadas ao ciclo de atividade solar. O método deverá ser aplicado à procura de efeitos sismo-eletromagnéticos utilizando caminhos com comprimento médios ou curtos. Foram realizadas simulações dos tempos TT, utilizando o código Long Wave Propagation Capability (LWPC), que mostraram boa concordância com as observações, sugerindo um valor de hN = 88 km para a altura noturna da baixa ionosfera. Os resultados apresentados neste trabalho contribuem para uma maior viabilização do uso da técnica de VLF, para o estudo da baixa ionosfera e os forçantes que agem sobre esta região da atmosfera terrestre.