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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Rôle de l’extrémité C-terminale dans l’expression du canal calcique Cav1.2 à la membrane plasmique

Le Coz, Florian 07 1900 (has links)
Le canal calcique de type L, Cav1.2, joue un rôle clé dans le couplage excitation-contraction des myocytes ventriculaires. Il a été montré que la sous-unité Cavα1 était sujette à l’épissage alternatif et que ce phénomène pouvait mener à une protéine tronquée en C-terminal au niveau de l’exon 45 (Liao, Yong et al. 2005). D’autres groupes ont étudié différentes délétions au niveau de l’extrémité C-terminale (De Jongh, Warner et al. 1991; Gao, Cuadra et al. 2001). Les courants mesurés dans la configuration cellule entière, était significativement plus grands que le canal « pleine longueur ». Nous avons décidé de tester certaines de ces délétions (ΔC2030, ΔC1935, ΔC1856, ΔC1733, ΔC1700) en présence ou en absence de la sous-unité auxiliaire Cavβ3, susceptible d’interagir avec l’extrémité C-terminale de la sous-unité Cavα1 par l’intermédiaire de son domaine SH3 (Lao, Kobrinsky et al. 2008). Les résultats obtenus dans les ovocytes de Xénope ont mis en évidence que les sous-unités Cavα1.2 tronquées montraient des courants globaux plus élevés que le canal « pleine longueur » en présence de la sous-unité auxiliaire Cavβ3 et que les sous-unités Cavα1.2 tronquées donnaient des courants en absence de la sous-unité Cavβ3 contrairement à la sous-unité Cavα1.2 « pleine longueur ». Afin de vérifier si l’augmentation des courants macroscopiques était le résultat d’une augmentation du nombre de sous-unités Cavα1.2 à la membrane, nous avons choisi de quantifier la fluorescence spécifiquement due à cette sous-unité en utilisant la méthode de cytométrie de flux (FACS : « Fluorescence Activated Cell Sorting »). L’épitope HA a été inséré dans une région extracellulaire de la sous-unité Cavα1 du canal calcique Cav1.2 et un anticorps anti-HA couplé au FITC (« Fluorescein IsoThioCyanate ») a été utilisé pour observer la fluorescence. Nos résultats confirment que la sous-unité Cavα1-HA du canal calcique Cav1.2, s’exprime à la membrane plasmique en présence de la sous-unité auxiliaire Cavβ3, et qu’en absence de celle-ci, ne s’exprime que peu ou pas à la membrane. Les mêmes résultats ont été obtenus pour les trois délétions testées dans les mêmes conditions soit Cavα1.2-HA ΔC1935, Cavα1.2-HA ΔC1856 et Cavα1.2-HA ΔC1733. Ensemble, ces résultats suggèrent que l’augmentation des courants macroscopiques observés après une délétion partielle du C-terminal n’est pas causée par une augmentation du nombre de protéines Cavα1.2 à la membrane. / The L-type calcium channel, Cav1.2, plays an important role in the excitation-contraction coupling of the ventricular myocytes. It has been shown that the alternative splicing of Cavα1.2 subunit could lead to a truncated protein in the C-terminus at exon 45 (Liao, Yong et al. 2005). Many groups have studied deletions in the C-terminus (De Jongh, Warner et al. 1991; Gao, Cuadra et al. 2001). The currents, measured in the whole cell configuration, were significantly higher with the full-length channel. We chose to test some of these deletions (ΔC2030, ΔC1935, ΔC1856, ΔC1733, ΔC1700) in the presence or absence of the Cavβ3 auxiliary subunit which is likely to interact with the C-terminus of the Cavα1.2 subunit through its SH3 domain (Lao, Kobrinsky et al. 2008). The truncated Cavα1.2 subunit, expressed in Xenopus Oocytes, showed macroscopic currents that were greater than those of the full length channel in presence of the Cavβ3 subunit. In addition, the truncated Cavα1.2 subunits displayed currents in the absence of the Cavβ3 subunit in contrast with the Cavα1.2 full length subunit. To investigate whether the larger macroscopic currents resulted in an increase in the number of Cavα1.2 subunits at the plasma membrane, we chose the FACS (« Fluorescence Activated Cell Sorting ») method. An HA-tag was inserted in an extracellular region of the Cavα1.2 subunit and a FITC (« Fluorescein IsoThioCyanate ») coupled anti-HA antibody was used to measure fluorescence. Our results showed that the Cavα1.2-HA subunit of L- type channel is expressed at the plasma membrane in the presence of the Cavβ3 subunit whereas the Cavα1.2-HA subunit is slightly or not expressed at the plasma membrane in its absence. The same results were obtained for the three C-terminal deletions tested under the same conditions (CaVα1.2-HA ΔC1935, CaVα1.2-HA ΔC1856 and CaVα1.2-HA ΔC1733). Taken together, these results suggest that the increased macroscopic currents observed after a partial deletion of the C-terminus is not caused by an increased number of Cavα1.2 proteins expressed at the plasma membrane. Keywords:
62

Rôle de l’extrémité C-terminale dans l’expression du canal calcique Cav1.2 à la membrane plasmique

Le Coz, Florian 07 1900 (has links)
Le canal calcique de type L, Cav1.2, joue un rôle clé dans le couplage excitation-contraction des myocytes ventriculaires. Il a été montré que la sous-unité Cavα1 était sujette à l’épissage alternatif et que ce phénomène pouvait mener à une protéine tronquée en C-terminal au niveau de l’exon 45 (Liao, Yong et al. 2005). D’autres groupes ont étudié différentes délétions au niveau de l’extrémité C-terminale (De Jongh, Warner et al. 1991; Gao, Cuadra et al. 2001). Les courants mesurés dans la configuration cellule entière, était significativement plus grands que le canal « pleine longueur ». Nous avons décidé de tester certaines de ces délétions (ΔC2030, ΔC1935, ΔC1856, ΔC1733, ΔC1700) en présence ou en absence de la sous-unité auxiliaire Cavβ3, susceptible d’interagir avec l’extrémité C-terminale de la sous-unité Cavα1 par l’intermédiaire de son domaine SH3 (Lao, Kobrinsky et al. 2008). Les résultats obtenus dans les ovocytes de Xénope ont mis en évidence que les sous-unités Cavα1.2 tronquées montraient des courants globaux plus élevés que le canal « pleine longueur » en présence de la sous-unité auxiliaire Cavβ3 et que les sous-unités Cavα1.2 tronquées donnaient des courants en absence de la sous-unité Cavβ3 contrairement à la sous-unité Cavα1.2 « pleine longueur ». Afin de vérifier si l’augmentation des courants macroscopiques était le résultat d’une augmentation du nombre de sous-unités Cavα1.2 à la membrane, nous avons choisi de quantifier la fluorescence spécifiquement due à cette sous-unité en utilisant la méthode de cytométrie de flux (FACS : « Fluorescence Activated Cell Sorting »). L’épitope HA a été inséré dans une région extracellulaire de la sous-unité Cavα1 du canal calcique Cav1.2 et un anticorps anti-HA couplé au FITC (« Fluorescein IsoThioCyanate ») a été utilisé pour observer la fluorescence. Nos résultats confirment que la sous-unité Cavα1-HA du canal calcique Cav1.2, s’exprime à la membrane plasmique en présence de la sous-unité auxiliaire Cavβ3, et qu’en absence de celle-ci, ne s’exprime que peu ou pas à la membrane. Les mêmes résultats ont été obtenus pour les trois délétions testées dans les mêmes conditions soit Cavα1.2-HA ΔC1935, Cavα1.2-HA ΔC1856 et Cavα1.2-HA ΔC1733. Ensemble, ces résultats suggèrent que l’augmentation des courants macroscopiques observés après une délétion partielle du C-terminal n’est pas causée par une augmentation du nombre de protéines Cavα1.2 à la membrane. / The L-type calcium channel, Cav1.2, plays an important role in the excitation-contraction coupling of the ventricular myocytes. It has been shown that the alternative splicing of Cavα1.2 subunit could lead to a truncated protein in the C-terminus at exon 45 (Liao, Yong et al. 2005). Many groups have studied deletions in the C-terminus (De Jongh, Warner et al. 1991; Gao, Cuadra et al. 2001). The currents, measured in the whole cell configuration, were significantly higher with the full-length channel. We chose to test some of these deletions (ΔC2030, ΔC1935, ΔC1856, ΔC1733, ΔC1700) in the presence or absence of the Cavβ3 auxiliary subunit which is likely to interact with the C-terminus of the Cavα1.2 subunit through its SH3 domain (Lao, Kobrinsky et al. 2008). The truncated Cavα1.2 subunit, expressed in Xenopus Oocytes, showed macroscopic currents that were greater than those of the full length channel in presence of the Cavβ3 subunit. In addition, the truncated Cavα1.2 subunits displayed currents in the absence of the Cavβ3 subunit in contrast with the Cavα1.2 full length subunit. To investigate whether the larger macroscopic currents resulted in an increase in the number of Cavα1.2 subunits at the plasma membrane, we chose the FACS (« Fluorescence Activated Cell Sorting ») method. An HA-tag was inserted in an extracellular region of the Cavα1.2 subunit and a FITC (« Fluorescein IsoThioCyanate ») coupled anti-HA antibody was used to measure fluorescence. Our results showed that the Cavα1.2-HA subunit of L- type channel is expressed at the plasma membrane in the presence of the Cavβ3 subunit whereas the Cavα1.2-HA subunit is slightly or not expressed at the plasma membrane in its absence. The same results were obtained for the three C-terminal deletions tested under the same conditions (CaVα1.2-HA ΔC1935, CaVα1.2-HA ΔC1856 and CaVα1.2-HA ΔC1733). Taken together, these results suggest that the increased macroscopic currents observed after a partial deletion of the C-terminus is not caused by an increased number of Cavα1.2 proteins expressed at the plasma membrane. Keywords:
63

Electronic structure of doped 2D materials

Fedorov, Alexander 25 May 2016 (has links) (PDF)
Electronic systems are an indivisible part of modern life. Every day, new materials, devices, passive components, antennas for wireless communication are needed to be designed and developed. In particular, flexible and biocompatible wearable devices are urgent required for medical and industrial applications. The great hope lies in the materials with high crystalline quality and flexibility such as graphene and other 2D semiconductors and insulators. Doping is a conventional tool for tailoring of the electronic properties of the functional materials. Here we examine application of the widely used the electron donor species to the graphene and hexagonal boron nitride monolayer (h-BN). For each we determine surface-interface properties and the full electronic band structure using the combination of the surface science methods such as angle-integrated and angle resolved photoemission (XPS, ARPES), electron diffraction (LEED) and photo absorption (XAS). As the result we provided insight into mechanisms underlying the doping gating of the graphene h-BN monolayer by the alkali metals. We fully characterized their surface and interface structure. Finally we studied the interplay between electrons and phonons in the doped graphene and we demonstrated that Ca-doped graphene is the promising candidate for realizing superconductivity in graphene.
64

Electronic structure of doped 2D materials

Fedorov, Alexander 05 April 2016 (has links)
Electronic systems are an indivisible part of modern life. Every day, new materials, devices, passive components, antennas for wireless communication are needed to be designed and developed. In particular, flexible and biocompatible wearable devices are urgent required for medical and industrial applications. The great hope lies in the materials with high crystalline quality and flexibility such as graphene and other 2D semiconductors and insulators. Doping is a conventional tool for tailoring of the electronic properties of the functional materials. Here we examine application of the widely used the electron donor species to the graphene and hexagonal boron nitride monolayer (h-BN). For each we determine surface-interface properties and the full electronic band structure using the combination of the surface science methods such as angle-integrated and angle resolved photoemission (XPS, ARPES), electron diffraction (LEED) and photo absorption (XAS). As the result we provided insight into mechanisms underlying the doping gating of the graphene h-BN monolayer by the alkali metals. We fully characterized their surface and interface structure. Finally we studied the interplay between electrons and phonons in the doped graphene and we demonstrated that Ca-doped graphene is the promising candidate for realizing superconductivity in graphene.
65

Gating Networks in Learning Machines for Multimodal Data : Decision Fusion on Single Modality Classifiers

Guðmundsson, Óttar January 2019 (has links)
Different architectures of gating networks that aggregate information from multiple modalities and their suitability for decision fusion is investigated. The research question, how does a gating network for decision fusion in multimodal classification problem compare to other alternatives, is answered by a quantitative and inductive reasoning approach. This is done by training different machine learning methods on individual modalities and fusing their predictions forthe final classification using M-MNIST, a new data set with three modalities (image, audio, and text). The gating networks achieve greater classification accuracy when fusing information from all modalities, in contrast to considering only one modality, or without fusion. The gating network potential is demonstrated by training it on modalities with different levels of classification accuracy where it achieves the highest average normalized gain when scoring the highest validation accuracy of the three fusion methods, where the results indicate that the gating network can suppress noise in the data. Moreover, by adding an additional weak modality to the gating network, the classification accuracy is improved, hinting at that there might be an incentive to use many weak modalities instead of a few strong ones. / Olika arkitekturer för gating-nätverk som aggregerar information från flera olika modaliteter undersöks här, liksom deras lämplighet för användning för att förena olika beslutsunderlag. Forskningsfrågan ”Hur bra står sig ett gating- nätverk för att ensa beslutsunderlag i multimodala klassificeringsproblem?” besvaras med ett kvantitativt och induktivt tillvägagångssätt. Olika maskininlärningsmetoder har tränats på singulära modaliteter och sedan ensa deras prediktioner för klassificering i M-MNIST: en ny ansamling data med tre modaliteter (bild, ljud och text). Nätverket uppnår bättre resultat i klassificeringen när information från alla modaliteter används, än när endast en modalitet används (eller utan ensning). Nätverkets potential har kunnat illustreras genom träning på modaliteter med olika nivåer av klassificeringskapacitet. Det får bästa resultat, mätt i högsta genomsnittliga normaliserade ökning, i samband med högsta valideringsresultat av de tre metoderna för ensning. Här indikerar resultaten att gating-nätverket kan undertrycka brus i datat. Genom att lägga till ytterligare en (svag) modalitet till nätverket så kan klassificeringens kvalitet ökas på, vilket antyder att det kan finnas skäl att använda många svaga modaliteter iställer för få starka modaliteter.
66

Respiratory Motion Correction in PET Imaging: Comparative Analysis of External Device and Data-driven Gating Approaches / Respiratorisk rörelsekorrigering inom PET-avbildning: En jämförande analys av extern enhetsbaserad och datadriven gating-strategi

Lindström Söraas, Nina January 2023 (has links)
Positron Emission Tomography (PET) is pivotal in medical imaging but is prone to artifactsfrom physiological movements, notably respiration. These motion artifacts both degradeimage quality and compromise precise attenuation correction. To counteract this, gatingstrategies partition PET data in synchronization with respiratory cycles, ensuring each gatenearly represents a static phase. Additionally, a 3D deep learning image registration modelcan be used for inter-gate motion correction, maximizing the use of the full acquired data. Thisstudy aimed to implement and evaluate two gating strategies: an external device-based approachand a data-driven centroid-of-distribution (COD) trace algorithm, and assess their impact on theperformance of the registration model. Analysis of clinical data from four subjects indicated thatthe external device approach outperformed its data-driven counterpart, which faced challengesin real-patient settings. Post motion compensation, both methods achieved results comparableto state-of-the-art reconstructions, suggesting the deep learning model addressed some data-driven method limitations. However, the motion corrected outputs did not exhibit significantimprovements in image quality over state-of-the-art standards. / Positronemissionstomografi (PET) är fundamentalt inom medicinsk avbildning men påverkasav artefakter orsakade av fysiologiska rörelser, framför allt andning. Dessa artefakter påverkarbildkvaliteten negativt och försvårar korrekt attenueringskorrigering. För att motverka dettakan tekniker för rörelsekorrigering tillämpas. Dessa innefattar gating-tekniker där PET-dataförst synkroniseras med andningscykeln för att därefter segmenterateras i olika så kalladegater som representerar en specifick respiratorisk fas. Vidare kan en 3D djupinlärningsmodellanvändas för att korrigera för rörelserna mellan gaterna, vilket optimerar användningen av allinsamlad data. Denna studie implementerade och undersökte två gating-tekniker: en externenhetsbaserad metod och en datadriven ”centroid-of-distribution (COD)” spår-algoritm, samtanalyserade hur dessa tekniker påverkar prestandan av bildregistreringsmodellen. Utifrånanalysen av kliniska data från fyra patienter visade sig metoden med den externa enhetenvara överlägsen den datadrivna metoden, som hade svårigheter i verkliga patient-situationer.Trots detta visade bildregistreringsmodellen potential att delvis kompensera för den datadrivnametodens begränsningar, då resultatet från båda strategeierna var jämförbara med befintligaklinisk bildrekonstruktion. Dock kunde ingen markant förbättring i bildkvalitet urskiljas av derörelsekorrigerade bilderna jämfört med nuvarande toppstandard.
67

Voltage-gating and assembly of split Kv10.1 channels

Tomczak, Adam 22 April 2016 (has links)
No description available.
68

Management of Respiratory Motion in Radiation Oncology

Vedam, Subrahmanya 01 January 2002 (has links)
Respiratory motion poses significant problems in the radiotherapy of tumors located at sites (lung, liver, pancreas, breast) that are affected by such motion. Effects of respiratory motion on the different stages of the radiotherapy process (imaging, treatment planning and treatment delivery), has formed the focus of significant research over the last decade. Results from such research have revealed that respiratory motion affects the instantaneous position of almost all structures in the thorax and abdomen to different degrees based on their corresponding anatomic location and muscular attachments. As an example, diaphragm motion was found to be of the order of 1.5 cm, predominantly in the superior-inferior (SI) direction during normal breathing. This indicates a similar magnitude of motion for tumors located in the lower lobes of the lung and in the abdomen.The conventional method of accounting for such motion is to add a margin (based on an estimate of the expected range of organ motion) around the clinical target volume (CTV) that is delineated from the image data. This margin also includes errors due beam-bony anatomy alignment during radiation delivery and errors in patient position between simulation and subsequent treatment delivery sessions. Such a margin estimate may or may not encompass the "current" extent of motion exhibited by the tumor, resulting in either a higher dose to the surrounding normal tissue or a potential cold spot in the tumor volume. Several clinical studies have reported the existence of a direct relationship between the reduction in mean dose to the lung and the incidence of radiation induced pneumonitis. Therefore, subjecting additional normal lung tissue to high dose radiation by adding large margins based on organ motion estimates may result in an increased risk of radiation induced lung injury.Monitoring and accounting for respiratory motion can however potentate a reduction in the amount of normal tissue that receives high dose radiation, thereby decreasing the probability of normal tissue complication and also increasing the possibility for dose escalation to the actual tumor volume. The management (monitoring and accounting) of respiratory motion during radiation oncology forms the primary theme of this dissertation.Specific aims of this thesis dissertation include (a) identifying the deleterious effects of respiratory motion on conventional radiation therapy techniques (b) examining the different solutions that have been proposed to counter the deleterious effects of respiratory motion during radiotherapy (c) summarizing the relevant work conducted at our institution as part of this thesis in addressing the issue of respiratory motion and (d) visualizing the future direction of research in the management of respiratory motion in radiation oncology.Among the various techniques available to manage respiratory motion in radiation oncology such as respiratory gated and breath hold based radiotherapy, our research initially focused on respiratory gated radiotherapy, employing a commercially available external marker based real time position monitoring system. Multiple session recordings of simultaneous diaphragm motion and external marker motion revealed a consistent linear relationship between the two signals indicating that the external marker motion (along the anterior-posterior (AP) direction) could be used as a "surrogate" for motion of internal anatomy (along the SI direction). The predictability of diaphragm motion based on such external marker motion both within and between treatment sessions was also determined to be of the order of 0.1 cm.Analysis of the parameters that affected the accuracy and efficacy of respiratory gated radiotherapy revealed a direct relationship between the amount of residual motion and the width of the "gate" window. It also followed therefore that a trade-off existed between the width of the "gate" and the accuracy of gated treatments and also the overall "Beam ON" time. Further, gating during exhale was found to be more reproducible than gating during inhale. Although, it was evident that a reduction in the width of the "gate" implied a reduction in the margins added around the clinical target volume (CTV), such a reduction was limited by setup error.A study of the potential gains that could be derived from respiratory gating (based on motion phantom experimental set up) indicated a potential CTV-PTV margin reduction of 0.2-1.1 cm while employing gating alone in combination with an electronic portal imaging device, thus decreasing the amount of healthy tissue receiving radiation. In addition, gating also improved the quality of images obtained during simulation by reducing the amount of motion artifacts that are typically seen during conventional spiral CT imaging.Imparting some form of training was hypothesized to better enable patients to breathe in a reproducible fashion, which was further thought to increase the accuracy and efficacy of gated radiotherapy, especially when the "gate" was set close to the inhale portion of the breathing cycle. An analysis of breathing patterns recorded from five patients over several sessions under conditions of normal quiet breathing, breathing with audio instructions and breathing with visual feedback indicated that training improved the reproducibility of amplitude or frequency of patient breathing cycles.An initial exploration into respiration synchronized radiotherapy was thought to facilitate realization of reduced margins without having to hold the radiation beam delivery during a breathing cycle (as is the case with gating). A feasibility study based on superimposition of respiratory motion of a tumor (simulated by a sinusoidal motion oscillator) onto the initial beam aperture as formed by the multileaf collimator (MLC) revealed that tumor dose measurements obtained with such a set up were equivalent to those delivered to a static tumor by a static beam.Finally, a feasibility study for a method to acquire respiration synchronized images of a motion phantom and a patient (in order to perform respiration synchronized treatment planning and delivery) yielded success in the form of a 4D CT data set with reduced motion artifacts.In summary, respiratory gated radiotherapy and respiration synchronized are both viable approaches to account for respiratory motion during radiotherapy. While respiratory gated radiotherapy has been successfully implemented in some centers, several technical advances are required to enable similar success in the implementation of respiration synchronized radiotherapy. However, the potential clinical gains that can be obtained from either of the above approaches and their relative contributions to margin reduction will determine their future applicability as routine treatment procedures.
69

Design optimization for obtaining zero defects in steel casting

Purkar, Pranit Pramod January 2019 (has links)
This thesis is about the design of the gating system and selection of proper alloy for defects free (grate bar) casting. The gating system plays an important role in casting manufacturing process. The gating system has different elements like pouring cup, sprue, well, runner, riser, and ingates. The function of the gating system is to provide molten metal to the mould cavity through different gating system elements.  Casting is a metal shaping process which is used to produce a cast component. The casting process depends upon the material, type of pattern, mould and various techniques like sand casting, investment casting, die casting, squeeze casting and lost foam casting. The sand mould casting process is used in this report. The casting process is used for making small to large cast parts, complicated shapes, and precision parts, etc. Making a casting without defects is an important requirement for its strength. The effective and efficient design of the gating system is necessary for making defects free castings. There are various defects like shrinkage cavity, porosity, pinholes, blowholes and incomplete filling that may occur in sand casting. The simulation software like Magma Soft and Nova Flow Solid are used to predict the possible defects in the casting. The uses of the simulation improve product quality and increase productivity. It also helps to reduce the rejection rate by identifying and controlling defects. This work is done at AB Bruzaholms Bruk as part of master thesis work at Jönköping University, Sweden. The company provides all the necessary data for simulation purposes. The design of the gating system is finalized as per company requirements and needs. The research questions that have been answered in this report based on the following points. 1) What does zero-defect mean? 2) Which is the best design among the ones that are prepared and simulated? 3) Which is the best alloy combination for casting parts that give defects free casting and better fluidity and filling?
70

Reduzindo o consumo de energia em MPSoCs heterogêneos via clock gating / Reducing energy consumption in heterogeneous MPSoCs through clock gating

Motta, Rodrigo Bittencourt January 2008 (has links)
Nesse trabalho é apresentada uma arquitetura que habilita a geração de MPSoCs (Multiprocessors Systems-on-Chip) heterogêneos escaláveis, baseados em barramento, suportando ainda o uso de diferentes organizações de memória. A comunicação entre as tarefas é especificada por meio de uma estrutura de memória compartilhada, que evita colisões e promove ganhos energéticos através do disparo dinâmico de clock gating. Também é introduzida a técnica DCF (Dynamic Core Freezing), que incrementa a eficiência energética do MPSoC tirando proveito dos ciclos ociosos dos processadores durante os acessos à memória. Mais, a combinação das organizações de memória propostas habilita a exploração de migração de tarefas na arquitetura proposta, por meio da troca de contexto das tarefas na memória compartilhada. Além disso, é mostrado o simulador de alto-nível, baseado na arquitetura proposta, criado com o propósito de extrair os ganhos energéticos propiciados com o uso do clock gating e da técnica DCF. O simulador aceita como entrada arquivos de trace de execução de aplicações Java, com os quais ele gera um novo arquivo contendo o mapeamento das instruções encontradas nos arquivos de trace para diferentes classes de instrução. Dessa forma, podem ser modeladas diferentes arquiteturas de processadores, usando o arquivo com o mapeamento para simular o MPSoC. Mais, o simulador habilita ainda a exploração das diferentes organizações de memória da arquitetura proposta, de maneira que se pode estimar o seu impacto no número de instruções executadas, contenções no barramento, e consumo energético. Experimentos baseados em uma aplicação sintética, executando em um MPSoC composto por diferentes versões de um processador Java mostram um grande aumento na eficiência energética com um custo mínimo em área. Além disso, também são apresentados experimentos baseados em aplicações do benchmark SPECjvm98, que mostram o impacto causado na eficiência energética quando o tipo de aplicação é alterado. Mais, os experimentos mostram drásticos ganhos energéticos obtidos com a aplicação da técnica DCF sobre as memórias do MPSoC. / In this work we present an architecture that enables the generation of bus-based, scalable heterogeneous Multiprocessor Systems-on-Chip (MPSoCs), supporting different memory organizations. Intertask communication is specified by means of a shared memory structure that assures collision avoidance and promotes energy savings through a dynamic clock gating triggering. We also introduce a Dynamic Core Freezing (DCF) technique, which boosts energy savings taking advantage of processor idle cycles during memory accesses. Moreover, the combination of the memory organizations enables the architecture to exploit easy task migration by means of the task context saving in the shared data memory. Moreover, we show the high-level simulator, based on the proposed architecture, created in order to extract the energy savings enabled with the clock gating and the DCF techniques. The simulator accepts as input execution trace files of Java applications, from which it generates a new file that contains the mapping of the instructions found in the trace file for different instruction classes. This way, we can model different processor architectures, using the mapping file to simulate the MPSoC. Also, the simulator enables us to experiment with different memory organizations to estimate their impact on the executed instructions, bus contention, and energy consumption. As case study we have modeled different versions of a Java processor in order to experiment with different execution patterns over different memory organizations. Experiments based on a synthetic application running on an MPSoC containing different versions of a Java processor show a large improvement in energy efficiency with a minimal area cost. Besides that, we also present experiments based on applications of the SPECjvm98 benchmark, which show the impact on the energy efficiency when we change the application type. Moreover, the experiments show a huge improvement in the energy efficiency when applying the DCF technique to the MPSoC memories.

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