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The purpose of this master thesis is to determine whether or not it exist, a model that can describethe reduction in strength, due to missing threads in a bond between a bolt and nut. And how thereduction in strength might effect a wall-shoe assembly, used to connect a wall to another wall or aconcrete base plate. This is done by firstly considering the strength of the entire wall-shoe assembly andthe strength of the bond between the nut and the bolt is then considered. The strength of the entire assembly is calculated using some simple analytical models. The strengthof the bolt is the limiting factor for the assembly given the analytical models. Four FEM-models arethen created, three to evaluate the strength of the bolt and nut assembly, for bolt sized from M6to M60 with thread engagement from one thread to seven threads.  An elastic model without a defined tensile stress limit is proposed. The maximum stress at the sharpgeometry changes (stress concentrations) are used to dimension the maximum allowed load accordingto the von Mises yield criterion.  The yield limit is implemented by introducing a elastic-plastic (without hardening) for three different materials. Where the maximum yield force is determined as the maximum reactionforce on the frictionless support boundary condition, when a displacement is applied. Material hardening is applied according to a bi-linear material model (with hardening). Thereaction force is evaluated and the maximum force and displacement can be determined using thedefinition of property class 8.8 that propose a yield limit of 80 percent of maximum load. The behavior of the anchor bolt when it is pulled out of the concrete was also modeled. To obtain anunderstanding of the pull-out behavior. The FEM-models makes it possible to formulate a simple reduction model, where the bolt failure loadis reduced by the calculated reduction factors. The reduction factors are dependent on the amountof missing thread due to damages or insufficient bolt height. The reduction factors are also highlydependent on the ratio between the rise and bolt diameter. The reduction factors are significantlysmaller when a perfect plastic material model is applied. The failure mode is dependent on the material model, when hardening is applied fewer threads areneeded to achieve bolt failure rather then thread failure, compared to when a ideal plastic materialmodel is applied. The reduction factors are not affected by the material yield limit, the maximal load is however highlydependent on the yield limit. The placement of the missing thread does not effect the reduction factors. They can therefor beused regardless of if threads are missing due to damage or due to partial thread engagement. A test of an M8 bolt was performed to attempt to validate the FEM-model. Due to some inherent flawsin the test procedure no clear conclusion, about the validity of the model can be made. It is howeverclear that missing threads induces risk of failure when tightening the assembly, since the bolt or nutcan be damaged without any clear signs that the assembly is compromised, leading to catastrophicfailure. Reducing the load with the reduction factor model should be done with caution. / Den här masteruppsatsen ämnar att besvara frågeställningen huruvida det finns en modell som kan beskriva den reduktion i hållfasthet, som förorsakas av ett bortfall av iskruvade gängor för ett förband mellan en bult och en mutter. Det görs genom att först betrakta styrkan för hela väggskoförbandet och delförbandet mellan bulten och muttern.  Hållfastheten av hela system som förbanden ämnar att sammanfoga (en vägg med grundplatta/vägg) beräknas. Fyra stycken FEM-modeller konstrueras sedan. Tre för att undersöka hållfastheten för bultar i storlekar mellan M6 och M60, med ett antal hela gängor med fullt ingrepp, i spannet från ett till sju. FEM-modell utan sträckgräns där maxlast beräknas med den maximala effektiva spänningen i modellen. En modell som kommer att visa sig vara bristfällig. FEM-modell där sträckgränsen implementeras för tre material, en elastik-plastisk material model utan härdning används. Den maximalt tillåtna kraften utvärderas med hjälp av reaktionskraften på det friktionsfria stödet. Där den maximalt beräknade antas motsvara förbandets sträckgräns.  En modell med bi-linjärt härdning. Reaktionskraften utvärderas och sambandet för Property Class 8.8 används för att bestämma förbandets maximalt tillåtna last. Alltså att sträckgränsen är 80 procent av brottgränsen. FEM model konstrueras för att få förståelse för hur brott för en ankarbult som dras ut ur betongen uppkommer. FEM-modellerna möjliggör en enkel modell baserat på reduktionsfaktorer där lasten reduceras för förbandet när gängvarv saknas, när gängorna är skadad eller när full mutter inte kan uppnås. Reduktionsfaktorn är lägre när den perfekt-plastiska modell används och större vid hårdnande.  Hur brottet sker ändras med materialmodellen. Den perfekt-plastisk model kräver fler gängor i ingrepp innan bulten går av, jämfört med när materialet kan hårdna vid plastisk deformation. Reduktionsfaktorerna är oberoende av materialets sträckgräns, den maximala lasten kommer dock ändras med sträckgränsen.  Placeringen av den avsaknade gängan verkar inte påverka reduktionsfaktorn, givet att en hel gänga saknas och att lika många gängor saknas.  Ett test med M8 gjordes för att testa bekräfta modellen men på grund av brister i testets utformning kunde inga slutsatser om FEM modellens giltighet göras. Det blev uppenbart att saknade gängor ökar riskan att förbandet brister när det spänns, eftersom gängorna kan förstöras utan utvändiga tecken på att det skett. Detta kan leda till ett plötsligt brott. Användandet av reducerings modellen för maxlast bör därför användas med försiktighet.

By 2004, microprocessor design focused on multicore scaling"increasing the number of cores per die in each generation "as the primary strategy for improving performance. These multicore processors typically equip multiple memory subsystems to improve data throughput. In addition, these systems employ heterogeneous processors such as GPUs and heterogeneous memories like non-volatile memory to improve performance, capacity, and energy efficiency. With the increasing volume of hardware resources and system complexity caused by heterogeneity, future systems will require intelligent ways to manage hardware resources. Early research to improve performance and energy efficiency on heterogeneous, multi-core, multi-memory systems focused on tuning a single primitive or at best a few primitives in the systems. The key limitation of past efforts is their lack of a holistic approach to resource management that balances the tradeoff between performance and energy consumption. In addition, the shift from simple, homogeneous systems to these heterogeneous, multicore, multi-memory systems requires in-depth understanding of efficient resource management for scalable execution, including new models that capture the interchange between performance and energy, smarter resource management strategies, and novel low-level performance/energy tuning primitives and runtime systems. Tuning an application to control available resources efficiently has become a daunting challenge; managing resources in automation is still a dark art since the tradeoffs among programming, energy, and performance remain insufficiently understood. In this dissertation, I have developed theories, models, and resource management techniques to enable energy-efficient execution of parallel applications through thread and data management in these heterogeneous multi-core, multi-memory systems. I study the effect of dynamic concurrent throttling on the performance and energy of multi-core, non-uniform memory access (NUMA) systems. I use critical path analysis to quantify memory contention in the NUMA memory system and determine thread mappings. In addition, I implement a runtime system that combines concurrent throttling and a novel thread mapping algorithm to manage thread resources and improve energy efficient execution in multi-core, NUMA systems. In addition, I propose an analytical model based on the queuing method that captures important factors in multi-core, multi-memory systems to quantify the tradeoff between performance and energy. The model considers the effect of these factors in a holistic fashion that provides a general view of performance and energy consumption in contemporary systems. Finally, I focus on resource management of future heterogeneous memory systems, which may combine two heterogeneous memories to scale out memory capacity while maintaining reasonable power use. I present a new memory controller design that combines the best aspects of two baseline heterogeneous page management policies to migrate data between two heterogeneous memories so as to optimize performance and energy. / Ph. D.

Computer architects continue to push the limits of modern microprocessors. By using techniques such as out-of-order execution, branch prediction, and dynamic scheduling, designers have found ways to speed execution. However, growing architectural complexity has led to unsustained development and testing times. Shrinking feature sizes are causing increased wire resistances and signal propagation, thereby limiting a design's scalability. Indeed, the method of exploiting instruction-level parallelism (ILP) within applications is reaching a point of diminishing returns. One approach to the aforementioned challenges is the Single-Chip Message-Passing (SCMP) Parallel Computer, developed at Virginia Tech. SCMP is a unique, tiled architecture aimed at thread-level parallelism (TLP). Identical cores are replicated across the chip, and global wire traces have been eliminated. The nodes are connected via a 2-D grid network and each contains a local memory bank. This thesis presents the design and analysis of three high-performance applications for SCMP. The results show that the architecture proves itself as a formidable opponent to several current systems. / Master of Science

This dissertation introduces two novel techniques, OSF and PBR, to improve the performance of Sparse Matrix-vector Multiply (SMVM) kernels, which dominate the runtime of iterative solvers for systems of linear equations. SMVM computations that use sparse formats typically achieve only a small fraction of peak CPU speeds because they are memory bound due to their low flops:byte ratio, they access memory irregularly, and exhibit poor ILP due to inefficient pipelining. We particularly focus on improving the flops:byte ratio, which is the main limiter on performance, by exploiting recurring structures or sub-structures in matrices. Our techniques also support micro-architecture level optimizations to further improve performance. Operation Stacking Framework (OSF) stacks problems in large ensemble computations, which run the same sparse kernel using an identical matrix structure, such that they share a single copy of the indexing information to significantly reduce memory bandwidth usage. OSF provides performance improvements of up to 1.94x on an AMD Opteron compared to the CSR method. We validate performance results using hardware event counters, which demonstrate significantly improved cache and pipeline utilization. Pattern-based Representation (PBR) exploits recurring block nonzero patterns by generating custom code for each recurring block pattern. In this way, no indexing data for individual nonzero elements are read from memory, reducing the overall size of the indices by up to 98%. Our code generator emits highly tuned codes that utilize SSE vectorization and software prefetching. PBR accurately identifies a block size that achieves optimal or near-optimal performance using a linear multiple regression performance model. On recent multicore machines, PBR provides performance improvements of up to 3.4x sequentially and 5x in parallel, compared to the CSR method. The PBR library we provide converts matrices at runtime, allowing our method to be used as a drop-in replacement for existing methods. We compare PBR's overhead relative to its benefits and show that PBR is beneficial for many applications that repetitively call the SMVM kernel for the same matrix structure. / Ph. D.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Safety critical systems are systems where its failures can cause irreparable damage for this reason the development of safety critical systems involves safety issues and require rigorous validation in the certification process. Certification processes are expensive and lengthy to follow laws and rigorous rules. With the continuous evolution provided by general purpose programming languages, ease of learning, and the use of these languages in industry and academy, researches have been performed aiming to adapt general purpose programming languages for use in safety-critical applications. The purpose of these adaptations is to reduce the scope of commands found in general purpose languages in order to develop safety critical systems, for example, to avoid or reduce the use of recursions. Some examples of these adaptations include the Real Time Specification for Java (RTSJ), developed in 1998 and Safety Critical Java. SCJ uses objects and concepts defined by the RTSJ focusing on the development of safetycritical applications. In SCJ, the concept of missions is deployed where each mission consists of schedulable objects defined by the RTSJ. The portability of a Java application is one of the main factors for choosing this language. However, there is great difficulty in finding virtual machines for embedded safety-critical systems, therefore it is difficult to benefit from the portability provided by the Java virtual machine in this context. Nevertheless, an application developed in the C++ programming language can be executed directly on the device without using a virtual machine. This work presents a translation of the Safety Critical Java to the C++ programming language, maintaining the behaviour of objects that implement the concept of missions for SCJ in C++. This enables the execution of safety-critical applications in embedded devices without the use of a virtual machine. / Sistemas críticos são sistemas em que suas falhas podem causar danos irreparáveis como colocar a vida de pessoas em risco e por este motivo envolve questões de segurança e exige uma validação rigorosa no processo de certificação. Processos de certificação são caros e demorados que seguem leis e regras rigorosas. Com a evolução contínua proporcionada por linguagens de programação de propósito geral, a facilidade de aprendizado, assim como a utilização destas linguagens na indústria e acadêmia, pesquisas vem sendo realizadas com o intuito de adaptar linguagens de programação de propósito gerais para serem utilizadas em aplicações críticas de tempo real. O objetivo destas adaptações é de tornar o escopo de comandos das linguagens para desenvolvimento de sistemas críticos mais restritos, como por exemplo, ao evitar ou reduzir a utilização de recursões. Alguns exemplos dessas adaptações são a Especificação de Tempo Real Java (Real Time Specification for Java - RTSJ) desenvolvida no ano de 1998, e a Safety Critical Java (SCJ) que utiliza objetos e conceitos definidos pela RTSJ com enfoque no desenvolvimento de aplicações para sistemas críticos. Na SCJ foi implementado o conceito de missões onde cada missão é composto por objetos escalonáveis definidos pela RTSJ. A portabilidade de uma aplicação desenvolvida em Java é um dos principais fatores dos quais desenvolvedores desejam utilizá-la. Todavia, existe uma grande dificuldade de encontrar máquinas virtuais para sistemas críticos embarcados, dificultando a portabilidade da qual a linguagem Java fornece. Por outro lado, uma aplicação desenvolvida na linguagem de programação C++ pode ser executada diretamente no dispositivo sem a necessidade de utilizar uma máquina virtual. Por este motivo, nesta dissertação é apresentada uma tradução da especificação Safety Critical Java na linguagem de programação C++, com o objetivo de manter o comportamentos de uma aplicação desenvolvida em SCJ e assim possibilitando a execução de uma aplicação com requisitos temporais em diversos dispositivos embarcados.

This master’s thesis deals with the obtuse-angled cone crushers especially about design of the individual parts of the adjustment mechanism. Most space is devoted to functional calculation and subsequent technical construction of the new design of obtuse-angled crusher where the output setting is adjusted using the motion thread and hydraulic locking system for compensating the thread clearance. The parameters are chosen with regard to the already established older types of cone crushers produced by PSP Engineering, a.s. An inseparable part is the calculation verifying the functionality of the motion thread and gearing. Another essential part of this work are stress analysis of the slot adjusting mechanism design using finite element method and considering two states - adjusting of the slot and crushing itself.

This thesis is focused on smart buildings where communication and automatization technologies are deployed. It includes overview and description of frequently applied network protocols in smart homes and their side by side comparison with an emphasis on Thread networking protocol. The next chapters describe details and parameters of used development boards provided by NXP Semiconductors and their implementation in a smart home model. Subsequent chapters are focused on hardware and software components which are the basis for smart home model’s internal workings. The last chapter highlights how a physical model of a smart home was developed with suggestions for future improvements.

Master of Science / Department of Horticulture, Forestry, and Recreation Resources / Jack D. Fry / Dollar spot, caused by Sclerotinia homoeocarpa F.T. Bennett, and silvery-thread moss (Bryum argenteum Hedw.) are pests affecting creeping bentgrass (Agrostis stolonifera L.) that typically require pesticide inputs. New strategies for pest management may reduce chemical inputs. The objectives of these 2009-2010 field studies were to evaluate: 1) creeping bentgrass cultivars for dollar spot susceptibility; 2) alternative chemical controls for silvery-thread moss; and 3) the response of silvery-thread moss to nitrogen (N) sources. During peak dollar spot development, ‘Declaration’, ‘A-4’, and ‘Crenshaw’ had 7.5, 139.4, and 288.9 infection centers m[superscript]-2 under fairway and 2.1, 27.2, and 106.9 infection centers m[superscript]-2 under putting green conditions, respectively. Two spring and two fall spot applications of sodium or potassium bicarbonate (45 g a.i. L[superscript]-1), premixed essential oil, and broadcast applications of carfentrazone-ethyl at 0.09 kg a.i. ha[superscript]-1 suppressed moss 39% to 55% compared to untreated in 2009. Spot sprays of sodium or potassium bicarbonate, and essential oil, were phytotoxic to creeping bentgrass and required up to 8 or 18 days, respectively, to return to acceptable quality. Fertilization with liquid urea (N at 16.3 kg ha[superscript]-1 biweekly, 210 kg ha[superscript]-1 annually) resulted in 147%, 150%, and 155% more moss than fertilization with IBDU, organic N, and granular urea, respectively, and 156% more moss compared to untreated. Fertilization with urea (liquid or granular) resulted in the best creeping bentgrass color. Averaged across the entire season, plots treated with organic N had unacceptable color in 2009. Nitrogen concentrations in moss tissue ranged from 0.4% to 1.0% and were always significantly lower than N concentrations observed in creeping bentgrass (1.1% to 2.1%), regardless of treatment. In 2010, moss treated with liquid urea had higher tissue N concentrations (1.0%) than untreated moss (0.5%) or that fertilized with IBDU (0.4%). In summary, use of dollar spot-resistant creeping bentgrass cultivars could reduce fungicide requirements. Bicarbonate and essential oil products can reduce moss severity at a similar level to carfentrazone-ethyl, but rates and/or application methods need to be optimized to avoid injury to creeping bentgrass. Applications of liquid urea enhanced moss coverage in creeping bentgrass compared to other N sources.