The effect of ultrafiltration, diafiltration, and preacidification of milk on the partition of specific milk components between retentate and permeate was studied. Percent retention (for any component Y) was determined as: [ l - (%Y in soln. permeate/%Y in soln. retentate)] X 100 where %Y in soln. = [%Y/(%Y + %H 20)] Simultaneous samples of retentate and permeate were taken at several points during each process. Percent retention of total solids, fat, total protein, rennet clottable nitrogen, lactose, total calcium, ionic calcium, sodium, phosphorous, and riboflavin was determined at each sampling point. Percent retention of β-carotene, vitamin B12, retinol, and zinc was determined at different stages of ultrafiltration only. As UF proceeded, percent retention of total solids, total protein, total calcium, ionic calcium, sodium, phosphorous, and riboflavin increased. Percent retention of lactose was not affected and was 0-4%. Percent retention of fat, rennet clottable nitrogen, zinc, retinal, β-carotene, and vitamin B12 was 99-100%. As diafiltration proceeded, percent retention of total solids, lactose, total calcium, ionic calcium, sodium, phosphorous, and riboflavin increased. Percent retention of these nutrients was increased when compared to ultrafiltration alone. Milks with lower pH values (resulting from preacidification) also had lower percent retention of total calcium and phosphorous than milks with normal pH values. Percent retention of sodium was lower during ultrafiltration and diafiltration of acidified milk when compared to ultrafiltration and diafiltration of normal milk. Percent retention of other nutrients was not affected by acidification. Loss of whey proteins into permeate resulted in a lower recovery of total protein after diafiltration than ultrafiltration alone and ultrafiltration of acidified milk. These proteins were determined to be α-lactogobulin and β-lactogobulin.

Crested wheatgrass (Agropyron cristatum [L.] Gaertn.) is one of the most commonly seeded exotic species in the western United States. Although many degraded Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) plant communities have been seeded with crested wheatgrass during rehabilitation efforts, seed banks of these communities have not been characterized. I sought to characterize and explain the variation among 33 seeded communities in the northeastern Great Basin. Hierarchical clustering and principal components analysis identified four possible seed bank categories in these communities. Seed bank categories varied from high to low crested wheatgrass dominance. The crested wheatgrass-dominated category is a particularly attractive setting to develop management strategies that reduce crested wheatgrass dominance and increase native plant diversity. It is also a common practice to seed crested wheatgrass in mixture with native species after a disturbance to increase diversity. Empirical estimates as to how the density of crested wheatgrass seed and seedlings interfere with native species establishment have not been defined. A greenhouse experiment was established using an addition series design to determine the influence of interference between crested wheatgrass and four important native species. The existence of seed bank categories of Wyoming big sagebrush communities seeded with crested wheatgrass agrees with the hypothesis that seed banks closely resemble floristic composition. In addition, these results support the hypothesis that seed bank composition has a strong influence on succession in these communities, and characterizing seed banks is necessary to develop ecologically based management strategies for seeded Wyoming big sagebrush communities. Interference from crested wheatgrass on many native species suggests that further management practices to enhance diversity in crested wheatgrass-dominated communities are necessary to reduce competition from crested wheatgrass in the seed bank as well as the aboveground vegetation. These results also suggest that the practice of simultaneously seeding native species with crested wheatgrass may likely result in poor native species persistence unless combined seed bank density and seeding rate of crested wheatgrass is sufficiently low.

Novos tratamentos térmicos e a otimização dos processos de conformação têm contribuído para o desenvolvimento de microestruturas multifásicas com excelente combinação de ductilidade e resistência mecânica. Parte dessa melhoria depende da presença de austenita retida, de sua estabilidade e fração volumétrica. O presente trabalho tem como objetivo caracterizar a evolução da microestrutura e comportamento das propriedades mecânicas do aço dual phase classe 600 (DP 600), após tratamentos térmicos intercríticos de têmpera e partição (Q&P) e reversão da martensita, assim como tratamentos termomecânicos de simulação física da estampagem a quente (HS), variando a deformação em 10% (HS 10) e 30% (HS 30), e combinando estampagem a quente com subsequente tratamento de têmpera e partição (HSQ&P). Duas condições microestruturais de partida diferentes foram utilizadas nos tratamentos térmicos. Para os tratamentos térmicos e termomecânicos Q&P, HS e HSQ&P a microestrutura de partida foi a bifásica (ferrita e martensita). Já para o tratamento térmico de reversão a microestrutura de partida foi modificada para martensítica. Os tratamentos puramente térmicos foram realizados no dilatômetro Bähr do Laboratório de Transformações de Fase (LTF); entretanto, os tratamentos termomecânicos foram feitos no simulador termomecânico Gleeble®, acoplado à linha de difração de raios X (XTMS) do Laboratório Nacional de Nanotecnologia (LNNano). A análise microestrutural foi feita com suporte de microscopia ótica (MO) e eletrônica de varredura (MEV-FEG), EBSD, e difração de raios X in situ e convencional. Avaliaram-se as propriedades mecânicas por ensaio de tração em corpos de prova sub-size e endentação instrumentada. As amostras Q&P, HS e HSQ&P foram submetidas a ensaios exploratórios de resistência ao trincamento por hidrogênio (HIC) segundo a norma NACE TM0284. Adicionalmente, foi feita a medição de hidrogênio ancorado na microestrutura estudada, após tratamentos, utilizando a técnica de dessorção térmica disponível no LNNano. A avaliação das mudanças microestruturais e de propriedades mecânicas após tratamentos térmicos foram discutidas separadamente para cada microestrutura de partida. Os resultados dos processos Q&P, HS e HSQ&P no aço, mostraram que a evolução da microestrutura levou a formação de uma microestrutura mais complexa do que a microestrutura ferrítico-martensítica simples do material como recebido. A complexa microestrutura é dada pela formação de ferrita epitaxial durante a etapa de tratamento intercrítico, ferrita induzida por deformação (DIFT) na etapa de deformação em alta temperatura e bainita na etapa de partição. Essa mistura microestrutural levou a variações na relação das frações volumétricas de ferrita e martensita em relação às frações iniciais do aço, assim como na presença de austenita retida e sua estabilidade. Com base nos resultados é possível afirmar que o processo Q&P produz um aumento nas propriedades mecânicas do material. Por outro lado, após o ensaio de HIC todas as amostras apresentaram susceptibilidade ao trincamento; contudo, a severidade do dano foi maior nas amostras deformadas HS 30. Os ensaios preliminares de dessorção mostraram maior aprisionamento de hidrogênio em armadilhas reversíveis nas amostras HSQ&P e irreversíveis na amostra HS 30. Na segunda parte, os resultados do tratamento de reversão sugerem que, em geral, a microestrutura do aço processado compreende uma morfologia em ripas de ferrita intercrítica, martensita e filmes de austenita retida. A maior temperatura de reversão intercrítica resultou em menor fração de ferrita intercrítica. Por outro lado, a temperatura intercrítica de reversão influenciou significativamente a estabilidade da austenita retida. Uma alta fração de austenita retida foi obtida a uma temperatura ligeiramente acima da temperatura Ac1. Um segundo ciclo de reversão promoveu a difusão de C e Mn para a austenita revertida tornando-a mais estável a temperatura ambiente. / Novel Heat Treatments and the optimization of the forming processes have contributed to the development of multiphase microstructures with attractive combinations of ductility and mechanical resistance. This improvement partially depends on the presence, stability and volume fraction of retained austenite. The objective of this work is to characterize the evolution of the microstructure and mechanical properties of a class 600 dual phase steel (DP 600), as a function of the thermal and thermomechanical history. Two initial microstructures were used in this study. A ferritic-martensitic microstructure was used as the starting condition for inter-critical heat treatments followed by quenching and partitioning (Q&P) and for the thermomechanical simulations of the hot stamping (HS) process. The latter applying deformations of 10% (HS 10) and 30% (HS 30) combining hot stamping with subsequent quenching and partition (HSQ&P). The thermal cycles were performed in a Bähr dilatometer at the Laboratory of Phase Transformations (LTF), then duplicated using a Gleeble® thermomechanical simulator, coupled to the X-ray Scattering and Thermo-mechanical Simulation beamline (XTMS) at the Brazilian Nanotechnology National Laboratory (LNNano). The microstructural analysis was performed using optical microscopy (MO) and scanning electron (SEM-FEG), Electron Backscatter Diffraction (EBSD), and in situ and conventional X-ray diffraction. The mechanical properties were evaluated by tensile testing on sub-size specimens and by instrumented macro-nano indentation tests. The evolution of the microstructure and mechanical properties for each starting microstructure was discussed separately. The Q&P, HS and HSQ&P samples were submitted to exploratory tests of resistance to hydrogen induced cracking (HIC) according to NACE TM0284. Additionally, hydrogen measurements were performed for the microstructures obtained after Q&P and HDQ&P using the thermal desorption technique at LNNano. After Q&P, HS and HSQ&P, the resultant microstructure was more complex than the as-received ferritic-martensitic condition. Such complexity comes from the formation of epitaxial ferrite from the former ferritic phase during the intercritical treatment step, the deformation induced ferrite (DIFT) and the bainite formation during the partitioning step. This led to variations in the volumetric fraction of ferrite and martensite in relation to the initial fractions of the as-received condition, as well as the presence of retained austenite and its stability upon cooling. The Q&P process increased the mechanical properties of the material. On the other hand, all microstructures showed susceptibility to hydrogen cracking after 72 hours of H2S exposure tests. However, the damage was more severe for the HS samples with 30% of deformation. The preliminary desorption tests showed greater hydrogen trapping in reversible traps after HSQ&P and in irreversible traps for the HS with 30% deformation. A second set of experiments was conducted for a different microstructure consisting of a fully martensitic matrix as the initial condition. After intercritical reversion, the resultant microstructure comprised intercritical lath-like ferrite, martensite laths and retained austenite films. The higher the intercritical reversion temperature, the smaller the fraction of intercritical ferrite. On the other hand, the transformation temperature significantly influenced the stability of the retained austenite. The highest fraction of retained austenite was obtained when the transformation occurred slightly above the Ac1 temperature. A double intercritical reversion cycle promoted the diffusion of C and Mn to the reversed austenite making it more stable upon cooling to room temperature, leading to a better combination of strength and ductility.

Natural categories seem to be comprised of clustered stimuli that contain a myriad of correlated features; birds, for example, tend to fly, have wings, lay eggs, and make nests. Nonetheless, the evidence that people use these correlations during intentional category learning is overwhelmingly negative (Murphy, 2002). People do, however, show evidence of correlational sensitivity during other types of category learning tasks (e.g., feature prediction). The usual explanation is that intentional category learning tasks promote rule use, which discards the correlated feature information; whereas, other types of category learning tasks promote exemplar storage, which preserves correlated feature information. However, all of the intentional category learning tasks employed to examine correlational sensitivity to date have only used deterministic mappings of stimuli to categories (i.e., each stimulus belongs to only one category). The current thesis is concerned primarily with the effects introducing the probabilistic assignment of stimuli to categories on the acquisition of different types of correlational knowledge. If correlational knowledge depends on whether or not people selectively attend to the correlation then probabilistic reinforcement, which is predicted to increase attention shifting (Kruschke & Johansen, 1999), should lead to increased correlational sensitivity. The first paper of this thesis confirms that selective attention provides a way to explain the presence or absence of correlational knowledge in different tasks. However, selective attention models have been unable to account for tasks in which people use the correlation between a non-relevant cue and regions of the category space to switch between the application of multiple rules. This phenomenon, known as knowledge partitioning, is explored in the second paper of this thesis. This thesis also extends the empirical implications of the first two papers to existing research (see included paper 3) and also provides recommendations of how utilize this conceptualization of knowledge for practitioners in the applied setting (see included paper 4). Finally, in addition to increasing attention shifting, probabilistic feedback is also assumed to result in an attenuation of learning over time (Kruschke & Johansen, 1999); the fifth paper in this thesis provides empirical confirmation that people attenuate learning in response to unavoidable error.

This thesis presents design automation methodologies for extensible processor platforms in application specific domains. The work presents first a single processor approach for customization; a methodology that can rapidly create different processor configurations by the removal of unused instructions sets from the architecture. A profile directed approach is used to identify frequently used instructions and to eliminate unused opcodes from the available instruction pool. A coprocessor approach is next explored to create an SoC (System-on-Chip) to speedup the application while reducing energy consumption. Loops in applications are identified and accelerated by tightly coupling a coprocessor to an ASIP (Application Specific Instruction-set Processor). Latency hiding is used to exploit the parallelism provided by this architecture. A case study has been performed on a JPEG encoding algorithm; comparing two different coprocessor approaches: a high-level synthesis approach and our custom coprocessor approach. The thesis concludes by introducing a heterogenous multi-processor system using ASIPs as processing entities in a pipeline configuration. The problem of mapping each algorithmic stage in the system to an ASIP configuration is formulated. We proposed an estimation technique to calculate runtimes of the configured multiprocessor system without running cycle-accurate simulations, which could take a significant amount of time. We present two heuristics to efficiently search the design space of a pipeline-based multi ASIP system and compare the results against an exhaustive approach. In our first approach, we show that, on average, processor size can be reduced by 30%, energy consumption by 24%, while performance is improved by 24%. In the coprocessor approach, compared with the use of a main processor alone, a loop performance improvement of 2.57x is achieved using the custom coprocessor approach, as against 1.58x for the high level synthesis method, and 1.33x for the customized instruction approach. Energy savings are 57%, 28% and 19%, respectively. Our multiprocessor design provides a performance improvement of at least 4.03x for JPEG and 3.31x for MP3, for a single processor design system. The minimum cost obtained using our heuristic was within 0.43% and 0.29% of the optimum values for the JPEG and MP3 benchmarks respectively.

In airline scheduling a variety of planning and operational decision problems have to be solved. In this thesis we consider the problems aircraft routing and crew pairing: aircraft and crew must be allocated to flights of a schedule in a minimal cost way. Although these problems are not independent, they are usually formulated as independent mathematical optimisation models and solved sequentially. This approach might lead to a suboptimal allocation of aircraft and crew, since a solution of one of the problems may restrict the set of feasible solutions of the problem solved subsequently. Also, in minimal cost solutions, aircraft and crew are highly utilised and short turn around times are usually used for aircraft and crew. If such a solution is used in operations, a short delay of one flight can cause very severe disruptions of the schedule later in the day due to the lack of buffer times. We formulate an integrated aircraft routing and crew pairing model that can generate solutions that incur small costs and are also robust to typical stochastic variability in airline operations. We propose two new solution methods to solve the integrated model. The first approach is an optimisation based heuristic approach that is capable of generating good quality solutions quickly, the second approach can solve the integrated model to optimality. In an extension of the integrated model we allow the departure times of some flights in the schedule to vary in some time window. This creates additional flexibility that leads to aircraft routing and crew pairing solutions with improved cost and robustness compared to the integrated model without time windows. Using data from domestic Air New Zealand schedules, we evaluate the benefits of the approaches on real world problem instances. Our solutions satisfy all rules imposed for these problems and are ready to be implemented in practice. We generate solutions that dramatically improve the cost and robustness of solutions obtained by existing methods.

<p>This thesis describes the design of fast JPEG processing accelerators for a DSP processor. </p><p>Certain computation tasks are moved from the DSP processor to hardware accelerators. The accelerators are slave co processing machines and are controlled via a new instruction set. The clock cycle and power consumption is reduced by utilizing the custom built hardware. The hardware can perform the tasks in fewer clock cycles and several tasks can run in parallel. This will reduce the total number of clock cycles needed. </p><p>First a decoder and an encoder were implemented in DSP assembler. The cycle consumption of the parts was measured and from this the hardware/software partitioning was done. Behavioral models of the accelerators were then written in C++ and the assembly code was modified to work with the new hardware. Finally, the accelerators were implemented using Verilog. </p><p>Extension of the accelerator instructions was given following a custom design flow.</p>

<p>This thesis describes an optimising compiler for translating from SMV to CLP(B). The optimisation is aimed at reducing the number of required variables in order to decrease the size of the resulting BDDs. Also a partitioning of the transition relation is performed. The compiler uses an internal representation of a FSM that is built up from the SMV description. A number of rewrite steps are performed on the problem description such as encoding to a Boolean domain and performing the optimisations. </p><p>The variable reduction heuristic is based on finding sub-circuits that are suitable for reduction and a state space search is performed on those groups. An evaluation of the results shows that in some cases the compiler is able to greatly reduce the size of the resulting BDDs.</p>

<p>H.264/AVC is a new video compression standard designed for future broadband network. Compared with former video coding standards such as MPEG-2 and MPEG-4 part 2, it saves up to 40% in bit rate and provides important characteristics such as error resilience, stream switching etc. However, the improvement in performance also introduces increase in computational complexity, which requires more powerful hardware. At the same time, there are several image and video coding standards currently used such as JPEG and MPEG-4. Although ASIC design meets the performance requirement, it lacks flexibility for heterogeneous standards. Hence reconfigurable DSP processor is more suitable for media processing since it provides both real-time performance and flexibility. </p><p>Currently there are several single scalar DSP processors in the market. Compare to media processor, which is generally SIMD or VLIW, single scalar DSP is cheaper and has smaller area while its performance for video processing is limited. In this paper, a method to promote the performance of single scalar DSP by attaching hardware accelerators is proposed. And the bottleneck for performance promotion is investigated and the upper limit of acceleration of a certain single scalar DSP for H.264/AVC decoding is presented. </p><p>Behavioral model of H.264/AVC decoder is realized in pure software during the first step. Although real-time performance cannot be achieved with pure software implementation, computational complexity of different parts is investigated and the critical path in decoding was exposed by analyzing the first design of this software solution. Then both functional acceleration and addressing acceleration were investigated and designed to achieve the performance for real-time decoding using available clock frequency within 200MHz.</p>

<p>In this thesis a method for solving the Generalized Assignment Problem (GAP) is described. It is based on a reformulation of the original problem into a Set Partitioning Problem (SPP), in which the columns represent partial solutions to the original problem. For solving this problem, column generation, with systematic overgeneration of columns, is used. Conditions that guarantee that an optimal solution to a restricted SPP is optimal also in the original problem are given. In order to satisfy these conditions, not only columns with the most negative Lagrangian reduced costs need to be generated, but also others; this observation leads to the use of overgeneration of columns.</p><p>The Generalized Assignment Problem has shown to be NP-hard and therefore efficient algorithms are needed, especially for large problems. The application of the proposed method decomposes GAP into several knapsack problems via Lagrangian relaxation, and enumerates solutions to each of these problems. The solutions obtained from the knapsack problems form a Set Partitioning Problem, which consists of combining one solution from each knapsack problem to obtain a solution to the original problem. The algorithm has been tested on problems with 10 agents and 60 jobs. This leads to 10 knapsack problems, each with 60 variables.</p>