Blast loads on buildings can originate from accidental explosions or from targeted attacks. Design against blast loads has become an increasingly important topic due to the current political climate. Unfortunately, many older buildings are constructed with unreinforced masonry (URM) walls which are particularly susceptible to out of plane failures caused by blast loads. One solution to increase the safety of these buildings is to retrofit them with advanced materials that can increase their out-of-plane stiffness and resistance. This thesis investigates the potential of using a high-performance shotcrete as a retrofit system for URM walls against blast effects. The shotcrete used in this study is made from Engineered Cementitious Composite (ECC), a special type of fiber-reinforced cementitious material, with high ductility and high energy-absorption capacity. The ECC shotcrete replaces aggregates with synthetic microfibers to increase tensile strength and ductility. A welded wire mesh was embedded in the shotcrete to provide ductile behavior. The testing program includes a total of six large-scale unreinforced masonry wall specimens. Two walls were constructed using concrete masonry unit (CMU) blocks to be retrofitted. The first specimen was built as an infill wall, experiencing no axial load, while the second specimen was built as a load bearing wall, with 10% axial load. Four more walls were built out of stone blocks. Two of the stone walls were controls: one infill and one load bearing (4% axial load). The other two stone walls were retrofit with the shotcrete system: one infill and one load bearing (4% axial load). The blast loads were simulated using the University of Ottawa’s Shock Tube. The walls were restrained at the top and bottom with a shear restraint to induce one way bending. Pressure, displacement and strain data were acquired with the use of pressure gauges, LVDT’s, strain gauges and cameras. The specimens were subjected to gradually increasing blast pressures until failure. The performance of the specimens was observed by analyzing the displacement, crack widths, fragmentation and failure mode. The results indicate the benefits of using ECC shotcrete as a retrofit system. The displacements of the retrofit walls were very small compared to the control walls, and fragments were limited. The specimens with axial load were found to have increased resistance. While the failure mode was brittle for the retrofit walls, this can be avoided with the use of a mesh with a larger area of steel. A SDOF analysis was performed to predict the blast response of the test walls. The analysis was done by generating resistance functions for the walls through analytical models. The analysis was found to agree reasonably well with the experimental data.

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De senaste åren har grafikkorten genomgått en omvandling från renderingsenheter till att klara av generella beräkningar, likt en vanlig processor. Med hjälp av språk som OpenCL blir grafikkorten kraftfulla enheter som går att använda effektivt vid stora beräkningar. Målet med detta examensarbete var att visa krypteringsalgoritmer som passar bra att accelerera med OpenCL på grafikkort. Ytterligare mål var att visa att programmet inte behöver omfattande omskrivning för att fungera i OpenCL. Två krypteringsalgoritmer portades för att kunna köras på grafikkorten. Den första algoritmen AES-256 testades i två olika implementationer, en 8- samt 32-bitars. Den andra krypteringsalgoritmen som användes var ECC ElGamal. Dessa två är valda för visa att både symmetrisk och öppen nyckelkryptering går att accelerera. Resultatet för AES-256 i ECB mod på GPU blev 7 Gbit/s, en accelerering på 25 gånger jämfört med CPU. För elliptiska kurvor ElGamal blev resultatet en acceleration på 55 gånger för kryptering och 67 gånger för avkryptering. Arbetet visar skalärmultiplikation med kurvan B-163 som tar 65us. Båda implementationerna bygger på dataparallellisering, där dataelementen distribueras över tillgänglig hårdvara. Arbetet är utfört på Syntronic Software Innovations AB i Linköping. / Last years, the graphic cards have become more powerful than ever before. A conversion from pure rendering components to more general purpose computing devices together with languages like OpenCL have created a new division for graphics cards. The goal of this thesis is to show that crypthography algorithms are well suited for acceleration with OpenCL using graphics cards. A second goal was to show that C-code can be easily translated into OpenCL kernel with just a small syntax change. The two algorithms that have been used are AES-256 implemented in 8- and 32-bits variants, and the second algorithm is Elliptic Curve Crypthography with the ElGamal scheme. The algoritms are chosen to both represent fast symmetric and the slower public-key schemes. The results for AES-256 in ECB mode on GPU, ended up with a throughtput of 7Gbit/s which is a acceleration of 25 times compared to a CPU. For Elliptic Curve, a single scalar point multiplication for the B-163 NIST curve is computed on the GPU in 65us. Using this in the ElGamal encryption scheme, an acceleration of 55 and 67 times was gained for encryption and decryption. The work has been made at Syntronic Software Innovations AB in Linköping, Sweden.

abstract: Error correcting systems have put increasing demands on system designers, both due to increasing error correcting requirements and higher throughput targets. These requirements have led to greater silicon area, power consumption and have forced system designers to make trade-offs in Error Correcting Code (ECC) functionality. Solutions to increase the efficiency of ECC systems are very important to system designers and have become a heavily researched area. Many such systems incorporate the Bose-Chaudhuri-Hocquenghem (BCH) method of error correcting in a multi-channel configuration. BCH is a commonly used code because of its configurability, low storage overhead, and low decoding requirements when compared to other codes. Multi-channel configurations are popular with system designers because they offer a straightforward way to increase bandwidth. The ECC hardware is duplicated for each channel and the throughput increases linearly with the number of channels. The combination of these two technologies provides a configurable and high throughput ECC architecture. This research proposes a new method to optimize a BCH error correction decoder in multi-channel configurations. In this thesis, I examine how error frequency effects the utilization of BCH hardware. Rather than implement each decoder as a single pipeline of independent decoding stages, the channels are considered together and served by a pool of decoding stages. Modified hardware blocks for handling common cases are included and the pool is sized based on an acceptable, but negligible decrease in performance. / Dissertation/Thesis / Masters Thesis Computer Science 2015

Ce travail de recherche est basé sur la technologie Ultra Large Bande (ULB), en particulier pour des applications bas débit (standard IEEE 802.15.4) tels que les réseaux de capteurs, les transmissions WPAN ou encore WBAN. La modélisation et la conception d’un récepteur non cohérent ULB pour les communications radio impulsionnelles ont été réalisées. Un des facteurs les plus importants dans les communications ULB est la sensibilité du récepteur, qui détermine la portée de transmission maximale. Un autre facteur aussi important est la consommation d’énergie qui influence directement la durée de vie de la source d’alimentation (batterie). Dans ce contexte, nous présentons dans le chapitre I une introduction sur la technologie ULB et ses diverses applications. Le chapitre II présente la modélisation au niveau système ainsi que d’une étude comparative des récepteurs non cohérents basés sur la détection d’énergie et la pseudo-Détection d’énergie. Dans le chapitre III sont présentés la méthode de conception et de réalisation d’un récepteur non cohérent ULB dans la bande de 3-5 GHz, ainsi que les résultats de mesure et ses performances en termes de sensibilité et de consommation d’énergie. Finalement, le chapitre IV présente une étude théorique sur les différents modes de fonctionnement du transistor MOS afin de mieux comprendre le fonctionnement de chaque bloc du récepteur. Cela permet de proposer de nouvelles architectures pour la détection d’énergie. Enfin, à partir de ces études nous réalisons l’optimisation du récepteur en termes de sensibilité et de consommation d’énergie. / This research is based on Ultra Wide Band (UWB) technology, in particularly for low-Rate applications such as sensor network, WPAN and WBAN (for the standard IEEE 802.15.4). The model and design of a non coherent receiver for UWB impulse radio communications has been completed. One of the most important factors in the UWB communications is the receiver sensitivity which determines the maximum transmission range. Another important factor is the energy consumption that determines the lifetime of the power source (battery). In this context, we present in Chapter I an introduction to UWB technology and its different applications. Chapter II deals with a modeling at the system level of non-Coherent receivers as well as a comparative study based on the energy detection and pseudo energy detection. In Chapter III is presented the method of design and implementation of a non-Coherent UWB receiver in the band of 3-5 GHz, as well as measurement results and performance in terms of sensitivity and power consumption. Finally, Chapter IV presents a theoretical study on the different modes of operation of the MOS transistor to understand the operation of each block of the receiver. This allows us to show the new architectures for energy detection and perform the optimization of receiver in terms of sensitivity and power consumption.

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This thesis describes the theory behind elliptic-curve Diffie-Hellman key exchanges. All the way from the definition of a group until how the operator over an elliptic curve forms an abelian group. This is illustrated with clear examples. After that a smaller study is made to determine if there is a connection betweenthe size of the underlying field, the amount of points on the curve and the order of the points to determine how hard it is to find out the secret key in elliptic-curve Diffie-Hellman key exchanges. No clear connection is found. Since elliptic curves over extension fields have more computational heavy operations, it is concluded that these curves serve no practical use in elliptic-curve Diffie-Hellman key exchange. / Denna rapport går igenom teorin bakom Diffie-Hellmans nyckelutbyte över elliptiska kurvor. Från definitionen av en grupp hela vägen till hur operatorn över en elliptisk kurva utgör en abelsk grupp gås igenom och görs tydligt med konstruktiva exempel. Sedan görs en mindre undersökning av sambandet mellan storleken av den underliggande kroppen, antal punkter på kurvan och ordning av punkterna på kurvan, det vill säga svårigheten att hitta den hemliga nyckeln framtagen med Diffie-Hellmans nyckelutbyte för elliptiska kurvor. Ingen tydlig koppling hittas. Då elliptiska kurvor över utvidgade kroppar har mer beräkningstunga operationer dras slutsatsen att dessa kurvor inte är praktiska inom Diffie-Hellman nyckelutbyte över elliptiska kurvor.

Objective: This purpose of this study was to describe pediatric medical residents' knowledge of oral health and dental-referral behavior and to examine factors that may influence whether providers can identify tooth decay, provide risk assessment or refer children to dental providers. The objective was to provide baseline data of pediatric medical residents prior to receiving the oral health education and training in the provision of preventive oral health services.Methods: This project utilized a cross-sectional prospective cohort study design. An oral health knowledge and referral behavior questionnaire was delivered to pediatric medical residents in training at two academic health centers. This project aimed to describe pediatric medical residents' knowledge of oral health and dental referral behavior as measured by the questionnaire. This study was designed to provide baseline information for a larger project called "Bright Smiles" developed by the Virginia Department of Health's Division of Dental Health. The self-administered questionnaire focused on extracting knowledge and opinions of residents and faculty in selected areas of infant oral- health services along with their confidence in providing these services. Results: The frequency of dental examinations correlated with how often providers see tooth decay in infants and toddlers. The frequency of examining for signs of dental decay was correlated with confidence in detecting tooth decay. The frequency of assessing the potential for developing tooth decay in infants and toddlers was correlated with the providers' confidence in evaluating risk of tooth decay. All above findings were correlated to a statistically significant value. Conclusion: Providers, while able to identify tooth decay in infants and toddlers, lack confidence in the ability to refer children to dental providers and the ability to perform certain aspects of oral-health risk assessment.

In many parallel programs, run-time data redistribution is usually required to enhance data locality and reduce remote memory access on the distributed memory multicomputers. For the heterogeneous computation environment, irregular data redistributions can be used to adjust data assignment. Since data redistribution is performed at run-time, there is a performance trade-off between the efficiency of the new data distribution for a subsequent phase of an algorithm and the cost of redistributing array among processors. Thus, efficient methods for performing data redistribution are of great importance for the development of distributed memory compilers for data-parallel programming languages. For the regular data redistribution, two approaches are presented in this dissertation, indexing approach and packing/unpacking approach. In the indexing approach, we propose a generalized basic-cycle calculation (GBCC) technique to efficiently generate the communication sets for a BLOCK-CYCLIC(s) over P processors to BLOCK-CYCLIC(t) over Q processors data redistribution. In the packing/unpacking approach, we present a User-Defined Types (UDT) method to perform BLOCK-CYCLIC(s) to BLOCK-CYCLIC(t) redistribution, using MPI user-defined datatypes. This method reduces the required memory buffers and avoids unnecessary movement of data. For the irregular data redistribution, in this dissertation, an Essential Cycle Calculation (ECC) method will be presented. The above methods are originally developed for one dimension array. However, the multi-dimension array can also be performed by simply applying these methods dimension by dimension starting from the first (last) dimension if array is in column-major (row-major).

The unprecedented demand for performance in the latest technologies will ultimately require changes in the way we design cache. Emerging high density embedded memories such as Spin-Transfer Torque Random Access Memory (STTRAM) have emerged as a possible candidate for universal memory due to its high speed, low power, non-volatility, and low cost. Although attractive, STTRAM is susceptible to contactless tampering through malicious exposure to magnetic field with the intention to steal or modify the bitcell content. In this thesis, we explore various attack techniques on STTRAM and then propose a novel array-based sensor to detect the polarity and magnitude of such attacks and then propose two design techniques to mitigate the attack. With our research, we have been able to successfully implement and accurately detect an attack while providing sufficient compensation window (few ns to ~100 us) to enable proactive protection measures. Finally, we show that variable-strength ECC can adapt correction capability to tolerate failures with various strength of an attack.