This thesis work shows the advantages of applying exergy-based analysis and optimization methods to the synthesis/design and operation an Advanced Aircraft Fighter (AAF) with three subsystems: a Propulsion Subsystem (PS), an Environmental Control Subsystem (ECS), and an Airframe Subsys-tem - Aerodyanmics (AFS-A) is used to illustrate these advantages. Thermodynamic (both energy and exergy), aerodynamic, geometric, and physical models of the components comprising the subsystems are developed and their interactions defined. An exergy-based parametric study of the PS and its components is first performed in order to show the type of detailed information on internal system losses. This is followed by a series of constrained, system synthesis/design optimizations based on five different objective functions, which define energy-based and exergy-based measures of performance. A first set of optimizations involving four of the objectives (two energy-based and two exergy-based) are performed with only PS and ECS degrees of freedom. Losses for the AFS-A are not incorporated into the two exergy-based objectives. The results show that as expected all four objectives globally produce the same optimum vehicle.A second set of optimizations is then performed with AFS-A degrees of freedom and again with two energy- and exergy-based objectives. However, this time one of the exergy-based objectives incorporates AFS-A losses directly into the objective. The results are that this latter objective produces a significantly better optimum vehicle. Thus, an exergy-based approach is not only able to pinpoint where the greatest inefficiencies in the system occur but produces a superior optimum vehicle as well by accounting for irreversibility losses in subsystems (e.g., the AFS-A) only indirectly tied to fuel usage. / Master of Science

Le bégaiement est un trouble complexe, qu'il est encore difficile de définir de manière satisfaisante et complète. Outre les symptômes secondaires, et comportements accompagnateurs, des facteurs langagiers peuvent interférer avec ce trouble. Des difficultés dans les compétence phonologiques pourraient être concomitantes, voire en interaction avec le bégaiement, avec notamment dans la parole adulte, un impact non négligeable de la complexité phonologique. Par ailleurs, des difficultés coarticulatoires seraient au cœur du bégaiement. Mais les résultats des différentes études sont très disparates, tant dans la parole des enfants que dans celle des adultes qui bégaient. Enfin, l'influence du feedback auditif est surprenante puisque toute modification de ce type de feedback a un pouvoir améliorant chez un certain nombre de personnes. Ce constat questionne la définition du bégaiement en tant que trouble de la production et l'oriente plutôt vers un trouble perceptivo-moteur. Cette thèse se propose d'étudier la parole fluente et disfluente de personnes bègues françaises et italiennes. Etant donné que les différences entre personnes qui bégaient et personnes fluentes, apparaissent essentiellement quand le système moteur est soumis à un facteur déstabilisant, nous avons choisi d'étudier l'adaptation du comportement coarticulatoire lorsque la complexité phonologique augmente. Nous avons également voulu analyser l'impact de la modification du feedback auditif sur le comportement coarticulatoire. Enfin, nous avons étudié le rôle de la complexité phonologique sur les disfluences notamment, dans une situation de dialogue autour d'une image. Des adultes et des enfants, italiens, et français, bègues et fluents ont été enregistrés dans 4 situations de parole : lectures, discours spontané, tâche de répétition, et tâche de description d'image. Toutes ces tâches ont été réalisées dans deux conditions perceptives : une condition normale, et une condition avec feedback auditif modifié. En condition perceptive normale, la coarticulation des personnes qui bégaient est plus faible que celle des personnes fluentes. La langue semble jouer également un rôle important puisque les personnes qui bégaient des deux langues ne se comportent pas toujours de la même manière vis-à-vis de leurs homologues fluents. Le comportement coarticulatoire des personnes bègues semble également sensible à l'augmentation de la complexité phonologique. Les résultats sous feedback auditifs modifiés apparaissent contradictoires. Par ailleurs, les disfluences pourraient être influencées par la complexité phonologique, mais cette influence semble dépendre de la sévérité du bégaiement et de l'âge du sujet. Des perspectives cliniques sont évoquées. / Stuttering is a complex (complicated-intricate) disorder, and it is difficult to give a satisfactory and complete definition of it. As well as secondary symptoms and entailed comportments, language factors can interfere in this disorder. Difficulties in phonological competence might be concomitant if not interactive in stuttering, with, mainly in adult language, an inconsiderable impact of the phonological complexity Furthermore, the coarticulatory difficulties might be at the core of stuttering. But the results of different studies diverge on the subject when both children and adults' stuttering are considered. And let us note that the influence of the auditory-feedback is surprising as every change in this feedback seems to have an improving power in an appreciable number of patients. So the definition of stuttering, being a production disorder, can be questioned. Stuttering rather appears as a perceptual motor disorder. The aim of this thesis is to study the fluent and disfluent language in French and Italian stutterers knowing that the differences between stutterers and fluent persons mainly appear when the motor system is conditional to a destabilizing factor. We chose to study how the coarticulatory behavior adapts when the phonological complexity increases. We also tried to analyze how the modification of the auditory-feedback influences the coarticulatory behavior. And we studied the part played by the phonological complexity on disfluencies mainly in a situation of dialogue over a picture. Italian and French adults and children stutterers and their fluent counterparts were registered placed in four different situations of language: reading, spontaneous speech, repetitive task and picture description and in two perceptive conditions: a normal one and one with modified auditory-feedback. When placed in normal perceptive condition, the stutterers' coarticulation is weaker than that of their fluent counterparts. Besides, the language seems to play an important role since Italian and French stutterers have not the same response towards their fluent counterparts. Let us note that this stutterers' coarticulatory comportment is also sensitive to the increase of the phonological complexity. The results we have when the auditory-feedback is altered are contradictory. Disfluency could also be influenced by phonological complexity but this influence seems to be dependent on the acuteness of the stuttering as well as on the stutterer's age. A significant clinical breakthrough is evoked

Um estudo prévio descreveu uma cepa de Escherichia coli enteropatogênica (EPEC) do sorotipo O142:H34 (Ec48/66) que apresentava o padrão de adesão agregativa (AA), característico de E. coli enteroagregativa (EAEC), e os genes eae e aatA. O objetivo deste estudo foi avaliar o papel de fímbrias no padrão AA dessa cepa. A mesma aderiu no padrão AA nas linhagens HeLa, HEp-2, HT-29 e T84, além de causar a lesão A/E em células HeLa e HT-29. Foi detectada a presença dos genes que compõem o operon da fímbria AAF/I de EAEC e da fímbria E. coli common pilus (ECP). Ambos os operons foram sequenciados mostrando alta identidade com os operons presentes em EAEC (agg) e EPEC (ecp). Mutantes nos genes aggC e ecpC mantiveram o padrão AA e a capacidade de causar a lesão A/E em células HeLa. O mutante em aggC apresentou diminuição significativa da adesão. Análises filogenéticas posicionaram essa cepa em um grupo constituído por EPEC. A cepa Ec48/66 é uma EPEC atípica que expressa o padrão AA, o qual é parcialmente dependente de uma variante de AAF/I, mas não de ECP. / A previous study described a strain of enteropathogenic Escherichia coli (EPEC), serotype O142:H34 (Ec48/66), presenting the aggregative adherence pattern (AA), typical of enteroaggregative E. coli (EAEC), and the eae and aatA genes. The aim of this study was to evaluate the role of fimbriae in the AA pattern of Ec48/66. This strain presented the AA pattern in HeLa, HEp-2, HT-29 and T84 cells, and the ability to cause the A/E lesion in HeLa and HT-29 cells. The presence of the genes comprising the operons of AAF/I fimbriae and E. coli common pilus (ECP) was detected. Both operons were sequenced showing high identity with the operons present in EAEC (agg) and EPEC (ecp). Mutants in the aggC and ecp genes maintained the AA pattern and the ability to cause the A/E lesion in HeLa cells. The aggC mutation significantly reduced the adherence. Phylogenetic analyzes located the strain in the group consisting of EPEC. The Ec48/66 strain is an atypical EPEC expressing the AA pattern, which is partially dependent on a variant of AAF/I, but not on ECP.

Um estudo prévio descreveu uma cepa de Escherichia coli enteropatogênica (EPEC) do sorotipo O142:H34 (Ec48/66) que apresentava o padrão de adesão agregativa (AA), característico de E. coli enteroagregativa (EAEC), e os genes eae e aatA. O objetivo deste estudo foi avaliar o papel de fímbrias no padrão AA dessa cepa. A mesma aderiu no padrão AA nas linhagens HeLa, HEp-2, HT-29 e T84, além de causar a lesão A/E em células HeLa e HT-29. Foi detectada a presença dos genes que compõem o operon da fímbria AAF/I de EAEC e da fímbria E. coli common pilus (ECP). Ambos os operons foram sequenciados mostrando alta identidade com os operons presentes em EAEC (agg) e EPEC (ecp). Mutantes nos genes aggC e ecpC mantiveram o padrão AA e a capacidade de causar a lesão A/E em células HeLa. O mutante em aggC apresentou diminuição significativa da adesão. Análises filogenéticas posicionaram essa cepa em um grupo constituído por EPEC. A cepa Ec48/66 é uma EPEC atípica que expressa o padrão AA, o qual é parcialmente dependente de uma variante de AAF/I, mas não de ECP. / A previous study described a strain of enteropathogenic Escherichia coli (EPEC), serotype O142:H34 (Ec48/66), presenting the aggregative adherence pattern (AA), typical of enteroaggregative E. coli (EAEC), and the eae and aatA genes. The aim of this study was to evaluate the role of fimbriae in the AA pattern of Ec48/66. This strain presented the AA pattern in HeLa, HEp-2, HT-29 and T84 cells, and the ability to cause the A/E lesion in HeLa and HT-29 cells. The presence of the genes comprising the operons of AAF/I fimbriae and E. coli common pilus (ECP) was detected. Both operons were sequenced showing high identity with the operons present in EAEC (agg) and EPEC (ecp). Mutants in the aggC and ecp genes maintained the AA pattern and the ability to cause the A/E lesion in HeLa cells. The aggC mutation significantly reduced the adherence. Phylogenetic analyzes located the strain in the group consisting of EPEC. The Ec48/66 strain is an atypical EPEC expressing the AA pattern, which is partially dependent on a variant of AAF/I, but not on ECP.

Modern architectures support multiple size pages to facilitate applications that use large chunks of contiguous memory either for buffer allocation, application specific memory management, in-memory caching or garbage collection. Most general purpose processors support larger page sizes, for e.g. x86 architecture supports 2MB and 1GB pages while PowerPC architecture supports 64KB, 16MB, 16GB pages. Such larger size pages are also known as superpages or huge pages. With the help of huge pages TLB reach can be increased significantly. The Linux kernel can transparently use these huge pages to significantly bring down the cost of TLB translations. With Transparent Huge Pages (THP) support in Linux kernel the end users or the application developers need not make any change to their application. Memory fragmentation which has been one of the classical problems in computing systems for decades is a key problem for the allocation of huge pages. Ubiquitous huge page support across architectures makes effective fragmentation management even more critical for modern systems. Applications tend to stress system TLB in the absence of huge pages, for virtual to physical address translation, which adversely affects performance/energy characteristics in long running systems. Since most kernel pages tend to be unmovable, fragmentation created due to their misplacement is more problematic and nearly impossible to recover with memory compaction. In this work, we explore physical memory manager of Linux and the interaction of kernel page placement with fragmentation avoidance and recovery mechanisms. Our analysis reveals that not only a random kernel page layout thwarts the progress of memory compaction; it can actually induce more fragmentation in the system. To address this problem, we propose a new allocator which takes special care for the placement of kernel pages. We propose a new region which represents memory area having kernel as well as user pages. Using this new region we introduce a staged allocator which with change in fragmentation level adapts and optimizes the kernel page placement. Later we introduce Illuminator which with zero overhead outperforms default kernel in terms of huge page allocation success rate and compaction overhead with respect to each huge page. We also show that huge page allocation is not a one dimensional problem but a two fold concern with how the fragmentation recovery mechanism may potentially interfere with the page clustering policy of allocator and worsen the fragmentation. Our results show that with effective kernel page placements the mixed page block counts reduces upto 70%, which allows our system to allocate 3x-4x huge pages than the default Kernel. Using these additional huge pages we show up to 38% improvement in terms of energy consumed and reduction in execution time up to 39% on standard benchmarks.