Affectation de composantes basée sur des contraintes énergétiques dans une architecture multiprocesseurs en trois dimensions

La lithographie et la loi de Moore ont permis des avancées extraordinaires dans la fabrication des circuits intégrés. De nos jours, plusieurs systèmes très complexes peuvent être embarqués sur la même puce électronique. Les contraintes de développement de ces systèmes sont tellement grandes qu’une bonne planification dès le début de leur cycle de développement est incontournable. Ainsi, la planification de la gestion énergétique au début du cycle de développement est devenue une phase importante dans la conception de ces systèmes. Pendant plusieurs années, l’idée était de réduire la consommation énergétique en ajoutant un mécanisme physique une fois le circuit créé, comme par exemple un dissipateur de chaleur. La stratégie actuelle est d’intégrer les contraintes énergétiques dès les premières phases de la conception des circuits. Il est donc essentiel de bien connaître la dissipation d’énergie avant l’intégration des composantes dans une architecture d’un système multiprocesseurs de façon à ce que chaque composante puisse fonctionner efficacement dans les limites de ses contraintes thermiques. Lorsqu’une composante fonctionne, elle consomme de l’énergie électrique qui est transformée en dégagement de chaleur. Le but de ce mémoire est de trouver une affectation efficace des composantes dans une architecture de multiprocesseurs en trois dimensions en tenant compte des limites des facteurs thermiques de ce système.

Le corps ambivalent dans l'exposition «En imparfaite santé : la médicalisation de l'architecture» (2011-2012)

Le progrès scientifique et technologique n'est pas sans faille – les conséquences imprévues de son application peuvent causer de nouveaux problèmes. Tel est le constat machiavélien sur lequel est fondé le projet En imparfaite santé : la médicalisation de l'architecture du Centre Canadien d'Architecture (2011-2012), présenté sous forme d'exposition et de catalogue. Ce mémoire étudie comment les deux plateformes, la première étant expérientielle et la seconde théorique, formulent une critique du processus de la médicalisation actuelle, lequel est entré dans le champ de l'architecture contemporaine. L’exposition est approchée comme discours et comme installation d’objets pour un public; une attention particulière est alors portée à la scénographie et au parcours du visiteur. D’autres réflexions ont pour objet le graphisme, un outil soutenant le leitmotiv de confrontation. Dans l’étude du catalogue, l’accent est mis sur l’essai d’introduction, qui est implicitement traversé par le concept fondamentalement ambivalent de pharmakon. Le péritexte, l’encadrement physique du contenu principal de l’ouvrage, est aussi examiné. Ensuite, l’analyse comparative propose que chaque plateforme véhicule un propos différent, une stratégie rendue possible par l’ambivalence de la notion de corps, entendue littéralement et métaphoriquement. La conclusion finale du mémoire esquisse une courte proposition de contextualisation, autant de cette dualité que de la remise en question de l’autorité du discours techno-scientifique. Bien qu’En imparfaite santé dirige sa critique envers la persistance de la vision moderniste de l'architecture, nous avançons que le projet concerne tout autant, sinon plus, l'omniprésence actuelle du numérique. Ce dernier, à l’instar de l’architecture moderne, ne modifie pas seulement la conception du corps humain et architectural, il renforce également une croyance positiviste dans la technologie qui n'est pas toujours contrebalancée par la pensée critique.

Projets et utopies au Québec : Les années 1960 et 1970 : entre sculpture et architecture

Depuis la publication de l’Utopia de Thomas More au XVIe siècle, la notion d’utopie s’est vue appropriée par différents domaines d’expression artistique. Bien vite, l’architecture et l’urbanisme en font leur apanage lorsqu’il est question de concilier, en des dessins et des plans, des sociétés idéalisées et leurs représentations. La modernité et les nouvelles technologies modifient les modalités de l’utopie qui tend alors vers l’actualisation de ses modèles en des projets construits. Le XXe siècle est aussi marqué par une abondance de formes et d’idées dont la transmission et le partage sont accélérés par la création de nouveaux médias. Si les années 1960 et 1970 sont le lieu d’émergence de formes expérimentales et de projets utopiques, notamment alimentés par la Révolution tranquille et Mai 68, il est encore difficile au Québec de retracer ces projets en arts et en architecture puisqu’ils sont peu documentés. Par l’étude de la pratique artistique d’Yvette Bisson (1926-), de Robert Roussil (1925-2013) et de Melvin Charney (1935-2012), ce mémoire propose d’observer les différentes tactiques d’appropriation de l’espace auxquelles s’apparentent les modalités de la sculpture de ces trois artistes. Par l’intermédiaire de Michel de Certeau, Henri Lefebvre et Louis Marin, nous chercherons à expliquer quelle est la teneur critique des imaginaires mis en œuvre par les trois artistes pour créer de nouveaux lieux utopiques de la sculpture.

Effect of Polymer Architecture on the Structural and Biophysical Properties of PEG-PLA Nanoparticles

Polymers made of poly(ethylene glycol) chains grafted to poly(lactic acid) chains (PEG-g-PLA) were used to produce stealth drug nanocarriers. A library of comb-like PEG-g-PLA polymers with different PEG grafting densities was prepared in order to obtain nanocarriers with dense PEG brushes at their surface, stability in suspension, and resistance to protein adsorption. The structural properties of nanoparticles (NPs) produced from these polymers by a surfactant-free method were assessed by DLS, zeta potential, and TEM and were found to be controlled by the amount of PEG present in the polymers. A critical transition from a solid NP structure to a soft particle with either a “micelle-like” or “polymer nano-aggregate” structure was observed when the PEG content was between 15 to 25% w/w. This structural transition was found to have a profound impact on the size of the NPs, their surface charge, their stability in suspension in presence of salts as well as on the binding of proteins to the surface of the NPs. The arrangement of the PEG-g-PLA chains at the surface of the NPs was investigated by 1H NMR and X-ray photoelectron spectroscopy (XPS). NMR results confirmed that the PEG chains were mostly segregated at the NP surface. Moreover, XPS and quantitative NMR allowed quantifying the PEG chain coverage density at the surface of the solid NPs. Concordance of the results between the two methods was found to be remarkable. Physical-chemical properties of the NPs such as resistance to aggregation in saline environment as well as anti-fouling efficacy were related to the PEG surface density and ultimately to polymer architecture. Resistance to protein adsorption was assessed by isothermal titration calorimetry (ITC) using lysozyme. The results indicate a correlation between PEG surface coverage and level of protein interactions. The results obtained lead us to propose such PEG-g-PLA polymers for nanomedecine development as an alternative to the predominant polyester-PEG diblock polymers.

Effect of polymer architecture on Curcumin 1 encapsulation and release from PEGylated polymer nanoparticles: toward a drug delivery nano-platform to the CNS

We developed a nanoparticles (NPs) library from poly(ethylene glycol)–poly lactic acid comb-like polymers with variable amount of PEG. Curcumin was encapsulated in the NPs with a view to develop a delivery platform to treat diseases involving oxidative stress affecting the CNS. We observed a sharp decrease in size between 15 and 20% w/w of PEG which corresponds to a transition from a large solid particle structure to a “micelle-like” or “polymer nano-aggregate” structure. Drug loading, loading efficacy and release kinetics were determined. The diffusion coefficients of curcumin in NPs were determined using a mathematical modeling. The higher diffusion was observed for solid particles compared to “polymer nano-aggregate” particles. NPs did not present any significant toxicity when tested in vitro on a neuronal cell line. Moreover, the ability of NPs carrying curcumin to prevent oxidative stress was evidenced and linked to polymer architecture and NPs organization. Our study showed the intimate relationship between the polymer architecture and the biophysical properties of the resulting NPs and sheds light on new approaches to design efficient NP-based drug carriers.

Analysis and Design of an Adaptive Polynomial Predistorter with the Loop Delay Estimator

Most adaptive linearization circuits for the nonlinear amplifier have a feedback loop that returns the output signal oj'tne eunplifier to the lineurizer. The loop delay of the linearizer most be controlled precisely so that the convergence of the linearizer should be assured lot this Letter a delay control circuit is presented. It is a delay lock loop (ULL) with it modified early-lute gate and can he easily applied to a DSP implementation. The proposed DLL circuit is applied to an adaptive linearizer with the use of a polynomial predistorter, and the simulalion for a 16-QAM signal is performed. The simulation results show that the proposed DLL eliminates the delay between the reference input signal and the delayed feedback signal of the linearizing circuit perfectly, so that the predistorter polynomial coefficients converge into the optimum value and a high degree of linearization is achieved

Indian Mathematics Related to Architecture and Other Areas With Special Reference to Kerala

Department of Mathematics, Cochin University of Science and Technology

Energy Management in Wireless Sensor Networks: A Crosslayer,Channel Adaptive Approach Towards Performance Optimization

The proliferation of wireless sensor networks in a large spectrum of applications had been spurered by the rapid advances in MEMS(micro-electro mechanical systems )based sensor technology coupled with low power,Low cost digital signal processors and radio frequency circuits.A sensor network is composed of thousands of low cost and portable devices bearing large sensing computing and wireless communication capabilities. This large collection of tiny sensors can form a robust data computing and communication distributed system for automated information gathering and distributed sensing.The main attractive feature is that such a sensor network can be deployed in remote areas.Since the sensor node is battery powered,all the sensor nodes should collaborate together to form a fault tolerant network so as toprovide an efficient utilization of precious network resources like wireless channel,memory and battery capacity.The most crucial constraint is the energy consumption which has become the prime challenge for the design of long lived sensor nodes.

An Error-Localization, Validation and Optimization Tool for Embedded Code Augmentation: an Architecture Oriented Approach

Embedded systems are usually designed for a single or a specified set of tasks. This specificity means the system design as well as its hardware/software development can be highly optimized. Embedded software must meet the requirements such as high reliability operation on resource-constrained platforms, real time constraints and rapid development. This necessitates the adoption of static machine codes analysis tools running on a host machine for the validation and optimization of embedded system codes, which can help meet all of these goals. This could significantly augment the software quality and is still a challenging field.Embedded systems are usually designed for a single or a specified set of tasks. This specificity means the system design as well as its hardware/software development can be highly optimized. Embedded software must meet the requirements such as high reliability operation on resource-constrained platforms, real time constraints and rapid development. This necessitates the adoption of static machine codes analysis tools running on a host machine for the validation and optimization of embedded system codes, which can help meet all of these goals. This could significantly augment the software quality and is still a challenging field.Embedded systems are usually designed for a single or a specified set of tasks. This specificity means the system design as well as its hardware/software development can be highly optimized. Embedded software must meet the requirements such as high reliability operation on resource-constrained platforms, real time constraints and rapid development. This necessitates the adoption of static machine codes analysis tools running on a host machine for the validation and optimization of embedded system codes, which can help meet all of these goals. This could significantly augment the software quality and is still a challenging field.Embedded systems are usually designed for a single or a specified set of tasks. This specificity means the system design as well as its hardware/software development can be highly optimized. Embedded software must meet the requirements such as high reliability operation on resource-constrained platforms, real time constraints and rapid development. This necessitates the adoption of static machine codes analysis tools running on a host machine for the validation and optimization of embedded system codes, which can help meet all of these goals. This could significantly augment the software quality and is still a challenging field.This dissertation contributes to an architecture oriented code validation, error localization and optimization technique assisting the embedded system designer in software debugging, to make it more effective at early detection of software bugs that are otherwise hard to detect, using the static analysis of machine codes. The focus of this work is to develop methods that automatically localize faults as well as optimize the code and thus improve the debugging process as well as quality of the code.Validation is done with the help of rules of inferences formulated for the target processor. The rules govern the occurrence of illegitimate/out of place instructions and code sequences for executing the computational and integrated peripheral functions. The stipulated rules are encoded in propositional logic formulae and their compliance is tested individually in all possible execution paths of the application programs. An incorrect sequence of machine code pattern is identified using slicing techniques on the control flow graph generated from the machine code.An algorithm to assist the compiler to eliminate the redundant bank switching codes and decide on optimum data allocation to banked memory resulting in minimum number of bank switching codes in embedded system software is proposed. A relation matrix and a state transition diagram formed for the active memory bank state transition corresponding to each bank selection instruction is used for the detection of redundant codes. Instances of code redundancy based on the stipulated rules for the target processor are identified.This validation and optimization tool can be integrated to the system development environment. It is a novel approach independent of compiler/assembler, applicable to a wide range of processors once appropriate rules are formulated. Program states are identified mainly with machine code pattern, which drastically reduces the state space creation contributing to an improved state-of-the-art model checking. Though the technique described is general, the implementation is architecture oriented, and hence the feasibility study is conducted on PIC16F87X microcontrollers. The proposed tool will be very useful in steering novices towards correct use of difficult microcontroller features in developing embedded systems.

Speech sample estimation from composite zerocrossings and encoding via adaptive switching of transforms

This thesis investigates the potential use of zerocrossing information for speech sample estimation. It provides 21 new method tn) estimate speech samples using composite zerocrossings. A simple linear interpolation technique is developed for this purpose. By using this method the A/D converter can be avoided in a speech coder. The newly proposed zerocrossing sampling theory is supported with results of computer simulations using real speech data. The thesis also presents two methods for voiced/ unvoiced classification. One of these methods is based on a distance measure which is a function of short time zerocrossing rate and short time energy of the signal. The other one is based on the attractor dimension and entropy of the signal. Among these two methods the first one is simple and reguires only very few computations compared to the other. This method is used imtea later chapter to design an enhanced Adaptive Transform Coder. The later part of the thesis addresses a few problems in Adaptive Transform Coding and presents an improved ATC. Transform coefficient with maximum amplitude is considered as ‘side information’. This. enables more accurate tfiiz assignment enui step—size computation. A new bit reassignment scheme is also introduced in this work. Finally, sum ATC which applies switching between luiscrete Cosine Transform and Discrete Walsh-Hadamard Transform for voiced and unvoiced speech segments respectively is presented. Simulation results are provided to show the improved performance of the coder

Modified Block Adaptive Predictive Coder For Speech Processing

This thesis investigated the potential use of Linear Predictive Coding in speech communication applications. A Modified Block Adaptive Predictive Coder is developed, which reduces the computational burden and complexity without sacrificing the speech quality, as compared to the conventional adaptive predictive coding (APC) system. For this, changes in the evaluation methods have been evolved. This method is as different from the usual APC system in that the difference between the true and the predicted value is not transmitted. This allows the replacement of the high order predictor in the transmitter section of a predictive coding system, by a simple delay unit, which makes the transmitter quite simple. Also, the block length used in the processing of the speech signal is adjusted relative to the pitch period of the signal being processed rather than choosing a constant length as hitherto done by other researchers. The efficiency of the newly proposed coder has been supported with results of computer simulation using real speech data. Three methods for voiced/unvoiced/silent/transition classification have been presented. The first one is based on energy, zerocrossing rate and the periodicity of the waveform. The second method uses normalised correlation coefficient as the main parameter, while the third method utilizes a pitch-dependent correlation factor. The third algorithm which gives the minimum error probability has been chosen in a later chapter to design the modified coder The thesis also presents a comparazive study beh-cm the autocorrelation and the covariance methods used in the evaluaiicn of the predictor parameters. It has been proved that the azztocorrelation method is superior to the covariance method with respect to the filter stabf-it)‘ and also in an SNR sense, though the increase in gain is only small. The Modified Block Adaptive Coder applies a switching from pitch precitzion to spectrum prediction when the speech segment changes from a voiced or transition region to an unvoiced region. The experiments cont;-:ted in coding, transmission and simulation, used speech samples from .\£=_‘ajr2_1a:r1 and English phrases. Proposal for a speaker reecgnifion syste: and a phoneme identification system has also been outlized towards the end of the thesis.

An adaptive cluster based routing scheme for mobile wireless sensor networks

Clustering schemes improve energy efficiency of wireless sensor networks. The inclusion of mobility as a new criterion for the cluster creation and maintenance adds new challenges for these clustering schemes. Cluster formation and cluster head selection is done on a stochastic basis for most of the algorithms. In this paper we introduce a cluster formation and routing algorithm based on a mobility factor. The proposed algorithm is compared with LEACH-M protocol based on metrics viz. number of cluster head transitions, average residual energy, number of alive nodes and number of messages lost

Channel Adaptive MAC Protocol with Traffic-Aware Distributed Power Management in Wireless Sensor Networks-Some Performance Issues

In Wireless Sensor Networks (WSN), neglecting the effects of varying channel quality can lead to an unnecessary wastage of precious battery resources and in turn can result in the rapid depletion of sensor energy and the partitioning of the network. Fairness is a critical issue when accessing a shared wireless channel and fair scheduling must be employed to provide the proper flow of information in a WSN. In this paper, we develop a channel adaptive MAC protocol with a traffic-aware dynamic power management algorithm for efficient packet scheduling and queuing in a sensor network, with time varying characteristics of the wireless channel also taken into consideration. The proposed protocol calculates a combined weight value based on the channel state and link quality. Then transmission is allowed only for those nodes with weights greater than a minimum quality threshold and nodes attempting to access the wireless medium with a low weight will be allowed to transmit only when their weight becomes high. This results in many poor quality nodes being deprived of transmission for a considerable amount of time. To avoid the buffer overflow and to achieve fairness for the poor quality nodes, we design a Load prediction algorithm. We also design a traffic aware dynamic power management scheme to minimize the energy consumption by continuously turning off the radio interface of all the unnecessary nodes that are not included in the routing path. By Simulation results, we show that our proposed protocol achieves a higher throughput and fairness besides reducing the delay

A Generic Software Architecture for a Domain Specific Distributed Embedded System

In this paper, we have evolved a generic software architecture for a domain specific distributed embedded system. The system under consideration belongs to the Command, Control and Communication systems domain. The systems in such domain have very long operational lifetime. The quality attributes of these systems are equally important as the functional requirements. The main guiding principle followed in this paper for evolving the software architecture has been functional independence of the modules. The quality attributes considered most important for the system are maintainability and modifiability. Architectural styles best suited for the functionally independent modules are proposed with focus on these quality attributes. The software architecture for the system is envisioned as a collection of architecture styles of the functionally independent modules identified