Search

Oxidative stress is an early occurrence in the development of Alzheimer’s disease (AD) and one of its proposed etiologic hypotheses. There is sufficient experimental evidence supporting the theory that impaired antioxidant enzymatic activity and increased formation of reactive oxygen species (ROS) take place in this disease. However, the antioxidant treatments fail to stop its advancement. Its multifactorial condition and the diverse toxicological cascades that can be initiated by ROS could possibly explain this failure. Recently, it has been suggested that cerebral small vessel disease (CSVD) contributes to the onset of AD. Oxidative stress is a central hallmark of CSVD and is depicted as an early causative factor. Moreover, data from various epidemiological and clinicopathological studies have indicated a relationship between CSVD and AD where endothelial cells are a source of oxidative stress. These cells are also closely related to oligodendrocytes, which are, in particular, sensitive to oxidation and lead to myelination being compromised. The sleep/wake cycle is another important control in the proliferation, migration, and differentiation of oligodendrocytes, and sleep loss reduces myelin thickness. Moreover, sleep plays a crucial role in resistance against CSVD, and poor sleep quality increases the silent markers of this vascular disease. Sleep disruption is another early occurrence in AD and is related to an increase in oxidative stress. In this study, the relationship between CSVD, oligodendrocyte dysfunction, and sleep disorders is discussed while focusing on oxidative stress as a common occurrence and its possible role in the onset of AD.

Supervisory systems have become interesting solutions for monitoring the health of home-based people. Frail older people are at high risk of becoming dependent if they are not cared for quickly. Embedded devices at home or on the person are two possible options which, when coupled, allow a more precise knowledge of behaviors and a faster triggering of the alert. The idea still applied is to model the person’s activities or health parameters in a continuous and automated way to detect deviations from the usual behavior. This clinico-technical approach has been developed and tested in different places and by several research teams with a real medical interest in having a longitudinal knowledge of a patient’s behavior. However, prevention and follow-up of home prescriptions must go beyond the purely technological and medical aspects and take economical and organizational dimensions into account. We consider that three types of complementary actions must be implemented: a fundamental action on the scientific and technological level to know how to build, from the data collected, “a profile of user activity;” detecting, in real time, all kinds of deviations from the normal pattern; training and ground demonstrations actions.

The nanoscale localization of individual paramagnetic defects near an electrical circuit is an important step for realizing hybrid quantum devices with strong spin-microwave photon coupling. Here, we demonstrate the fabrication of an array of individual NV centers in diamond near a metallic nanowire deposited on top of the substrate. We determine the relative position of each NV center with $\sim$10\,nm accuracy, using it as a vector magnetometer to measure the field generated by passing a dc current through the wire., 6 pages, 5 figures

Biomarkers for disease diagnosis and prognosis are crucial in clinical practice. They should be objective and quantifiable and respond to specific therapeutic interventions. Optimal biomarkers should reflect the underlying process (pathological or not), be reproducible, widely available, and allow measurements repeatedly over time. Ideally, biomarkers should also be non-invasive and cost-effective. This review aims to focus on the usefulness and limitations of electroencephalography (EEG) in the search for Alzheimer’s disease (AD) biomarkers. The main aim of this article is to review the evolution of the most used biomarkers in AD and the need for new peripheral and, ideally, non-invasive biomarkers. The characteristics of the EEG as a possible source for biomarkers will be revised, highlighting its advantages compared to the molecular markers available so far.

Obesity is known to induce leptin and insulin resistance. Leptin is a peptide hormone synthesized in adipose tissue that mainly regulates food intake. It has been shown that insulin stimulates the production of leptin when adipocytes are exposed to glucose to encourage satiety; while leptin, via a negative feedback, decreases the insulin release and enhances tissue sensitivity to it, leading to glucose uptake for energy utilization or storage. Therefore, resistance to insulin is closely related to leptin resistance. Obesity in middle age has also been related to Alzheimer’s disease (AD). In recent years, the relation between impaired leptin signaling pathway and the onset of AD has been studied. In all this context the role of the blood brain barrier (BBB) is crucial. Slow excitotoxicity happens in AD due to an excess of the neurotransmitter glutamate. Since leptin has been shown to regulate N-methyl-D-aspartate (NMDA) receptors, we want to review the link between these pathological pathways, and how they are affected by other AD triggering factors and its role in the onset of AD.

Nature sets fundamental limits regarding how accurate the amplification of analog signals may be. For instance, a linear amplifier unavoidably adds some noise which amounts to half a photon at best. While for most applications much higher noise levels are acceptable, the readout of microwave quantum systems, such as spin or superconducting qubits, requires noise as close as possible to this ultimate limit. To date, it is approached only by parametric amplifiers exploiting non-linearities in superconducting circuits and driven by a strong microwave pump tone. However, this microwave drive makes them much more difficult to implement and operate than conventional DC powered amplifiers, which so far suffer from much higher noise. Here we present the first experimental proof that a simple DC-powered setup allows for amplification close to the quantum limit. Our amplification scheme is based on the stimulated microwave photon emission accompanying inelastic Cooper pair tunneling through a DC-biased Josephson junction, with the key to low noise lying in a well defined auxiliary idler mode, in analogy to parametric amplifiers., Comment: 6 pages, 4 figures

International audience; Healthcare Systems (HCSs) throughout the world undergo important changes driven by aging populations and advances in biomedical technologies. At the same time, in the current economic climate, many Western countries are struggling to reduce public spending on all kinds of services, including healthcare. With this tension between tightening budgets and skyrocketing costs, many countries are seeking to identify ways of using Information Technology (IT) and Monitoring Technologies (MTs) to improve the efficiencies of HCSs while not reducing, or possibly even improving, the quality of healthcare and their delivery. Many experiments have been in progress since the 1990s. This paper has conducted a review evaluating such HCSs in terms of advantages and drawbacks. The objective of this review is to provide some illustrative publications and works and examples of Health Information Technology (HIT) systems to finally determine the place of biomedical MTs in the future HCS. We present the healthcare delivery system (HCDS) organization with roles of the different stakeholders, state initiatives in healthcare information delivery systems and the new relation between the hospital and the home though a new equilibrium. We mentioned the increasing role of telemedicine (TM), telecare (TLC) and telemonitoring (TLM) and expectations for monitoring the elderly. These expectations lead to preventive approaches based on monitoring technologies and pervasive healthcare (PH) which made healthcare improvements and cost reductions possible. Finally, we show the challenges and opportunities of the hospital versus home healthcare delivery.

While Alzheimer’s disease (AD) classical diagnostic criteria rely on clinical data from a stablished symptomatic disease, newer criteria aim to identify the disease in its earlier stages. For that, they incorporated the use of AD’s specific biomarkers to reach a diagnosis, including the identification of Aβ and tau depositions, glucose hypometabolism, and cerebral atrophy. These biomarkers created a new concept of the disease, in which AD’s main pathological processes have already taken place decades before we can clinically diagnose the first symptoms. Therefore, AD is now considered a dynamic disease with a gradual progression, and dementia is its final stage. With that in mind, new models were proposed, considering the orderly increment of biomarkers and the disease as a continuum, or the variable time needed for the disease’s progression. In 2011, the National Institute on Aging and the Alzheimer’s Association (NIA-AA) created separate diagnostic recommendations for each stage of the disease continuum—preclinical, mild cognitive impairment, and dementia. However, new scientific advances have led them to create a unifying research framework in 2018 that, although not intended for clinical use as of yet, is a step toward shifting the focus from the clinical symptoms to the biological alterations and toward changing the future diagnostic and treatment possibilities. This review aims to discuss the role of biomarkers in the onset of AD.

Today, the monitoring of dependent people is a real challenge. This is mainly due to the increase in the number of elderly and reduction of medical staff. However, works done in recent years in France are faced with obstacle of clinical and industrial validation. In this paper, we propose a monitoring system for dependent persons living alone at home or in an institution 24 h/24. This system is based on a presence multisensor network deployed in the living environment of the monitored person coupled with a wireless identification system. A learning algorithm is implemented in order to define a personalized behavioural model (motions deviation, nocturnal activity, falls, mobility). This model allows the nursing staff monitoring the behaviour through a web application accessed remotely, and also intervention in case of dangerous situations thanks to an alert system. In further, we describe the experiments conducted at the Caussade Local Hospital in France with Alzheimer patients and we present the results of data obtained. Finally, we propose the way for an economic model that would allow to industrialize the system with prospects of clinical validation on a larger cohort of patients.

Distributed sensors allow people to be followed in independent living situations. In this paper, the authors present a multisensor system which allows monitoring elderly people in hospital environment. The system is composed of motion infrared sensors installed in the ceiling, presence sensor in bed and ZigBee tags embedded on the person. From data collected on locations and movements of people, the system determines, through learning, the behavior model and lifestyle. Analysis and decision algorithm in integrated systems provide the functionality to choose actions in order to alert surveillance team and help them by providing historical events record. A web application is also set up to display results of data processing allowing caregivers to monitor patient behavior. Here, they present the system architecture, the technology used, and some preliminary results.

Objective: Extensive efforts have been made in both academia and industry in the research and development of smart wearable systems (SWS) for health monitoring (HM). Primarily influenced by skyrocketing healthcare costs and supported by recent technological advances in micro- and nanotechnologies, miniaturisation of sensors, and smart fabrics, the continuous advances in SWS will progressively change the landscape of healthcare by allowing individual management and continuous monitoring of a patient's health status. Consisting of various components and devices, ranging from sensors and actuators to multimedia devices, these systems support complex healthcare applications and enable low-cost wearable, non-invasive alternatives for continuous 24-h monitoring of health, activity, mobility, and mental status, both indoors and outdoors. Our objective has been to examine the current research in wearable to serve as references for researchers and provide perspectives for future research. Methods: Herein, we review the current research and development of and the challenges facing SWS for HM, focusing on multi-parameter physiological sensor systems and activity and mobility measurement system designs that reliably measure mobility or vital signs and integrate real-time decision support processing for disease prevention, symptom detection, and diagnosis. For this literature review, we have chosen specific selection criteria to include papers in which wearable systems or devices are covered. Results: We describe the state of the art in SWS and provide a survey of recent implementations of wearable health-care systems. We describe current issues, challenges, and prospects of SWS. Conclusion: We conclude by identifying the future challenges facing SWS for HM.

Vitamin E was proposed as treatment for Alzheimer’s disease many years ago. However, the effectiveness of the drug is not clear. Vitamin E is an antioxidant and neuroprotector and it has anti-inflammatory and hypocholesterolemic properties, driving to its importance for brain health. Moreover, the levels of vitamin E in Alzheimer’s disease patients are lower than in non-demented controls. Thus, vitamin E could be a good candidate to have beneficial effects against Alzheimer’s. However, evidence is consistent with a limited effectiveness of vitamin E in slowing progression of dementia; the information is mixed and inconclusive. The question is why does vitamin E fail to treat Alzheimer’s disease? In this paper we review the studies with and without positive results in Alzheimer’s disease and we discuss the reasons why vitamin E as treatment sometimes has positive results on cognition but at others, it does not.

Capacitive RF MEMS switches suffer from reliability issues, originating from mechanical fatigue or dielectric charging. In this work we focus on the charging effect of capacitive RF switches, fabricated on glass substrate with Si 3 N 4 as a dielectric. The drift of the actuation parameters, namely the pull-in/pull-out voltages, are monitored and compared with two failure criteria, in order to estimate the time to failure (TTF). It is shown that the characteristics of the bias signal can significantly influence the switch’s reliability. It is clearly demonstrated that increased actuation bias signal amplitude and duty cycle, can accelerate the switch degradation. Another environmental parameter found to influence the TTF is temperature. An improved predictive model is proposed in order to take into account all these effects.

In an ageing world, maintaining good health and independence for as long as possible is essential. Instead of hospitalization or institutionalization, the elderly and disabled can be assisted in their own environment 24h a day with numerous 'smart' devices. The concept of the smart home is a promising and cost-effective way of improving home care for the elderly and the disabled in a non-obtrusive way, allowing greater independence, maintaining good health and preventing social isolation. Smart homes are equipped with sensors, actuators, and/or biomedical monitors. The devices operate in a network connected to a remote centre for data collection and processing. The remote centre diagnoses the ongoing situation and initiates assistance procedures as required. The technology can be extended to wearable and in vivo implantable devices to monitor people 24h a day both inside and outside the house. This review describes a selection of projects in developed countries on smart homes examining the various technologies available. Advantages and disadvantages, as well as the impact on modern society, are discussed. Finally, future perspectives on smart homes as part of a home-based health care network are presented.

This paper deals with a new integration step for home automation functions: comfort and security, that give higher performances and decrease in installation costs. From experiences on previous projects: ERGDOM, PROSAFE, we focus our discussion on the analysis and specifications of the desirable characteristics for a generic presence sensor. This sensor is thought to be the key element to constitute a learning basis both for comfort and behaviour monitoring. In this article, two technological ways are investigated leading to an industrial device in pyroelectrical approach and to a compatible laboratory's device in thermoelectrical approach. Finally, we discuss about a new tendency which is to introduce at home a mobile mini-robot to improve diagnosis and to give the first assistance to the users.

In the era of information technology, the elderly and disabled can be monitored with numerous intelligent devices. Sensors can be implanted into their home for continuous mobility assistance and non-obtrusive disease prevention. Modern sensor-embedded houses, or smart houses, cannot only assist people with reduced physical functions but help resolve the social isolation they face. They are capable of providing assistance without limiting or disturbing the resident's daily routine, giving him or her greater comfort, pleasure, and well-being. This article presents an international selection of leading smart home projects, as well as the associated technologies of wearable/implantable monitoring systems and assistive robotics. The latter are often designed as components of the larger smart home environment. The paper will conclude by discussing future challenges of the domain.

In this paper, we are interested in “good practices” of Systems Engineering synthesized in processes of Systems Engineering. We will show that it necessarily exists gaps between the processes described by standards of Systems Engineering and such they are applied in industry. These gaps can create a loss of “good properties” detrimental to a good management of projects. By a modeling and a formal validation of processes, we will show it is possible of insure a conservation of these properties, or at least to verify they appear in effectively applied processes.

A new planar structure of solid propellant micro-rocket for micro-spacecraft and micro-air-vehicle applications is reported in this paper. We have successfully fabricated an array of micro-rockets using MEMS technology. For a low-power consumption, the micro-igniter used here is a resistor deposited on a low tensile stress thin membrane to ensure a good heat transfer to the propellant. Experimental tests of ignition and microcombustion employing double-base (DB) solid propellant mixed with black-powder (BP) are reported and discussed. Tests have showed successful and continuum combustion of about 1.3 mm diameter during few 100 ms from BP ratio in the mixture (x) of 10%. Thrust force delivered by considered structure dimensions, is ranging from 0.1 to 1 mN for x = 10%, 20% and 30%. We expect that this planar structure will deliver a suitable thrust force of few 10 mN when reducing micro-nozzle throat dimensions.

International audience; Too many industrial projects still fail, mainly due to the managerial techniques used. Indeed, organizational processes are more or less specifically mentioned in systems engineering standards, but in practice, project managers tend to rely more on their own standards, which sometimes set forth practices that do not align with those of the systems engineering domain, hence the reported discrepancies that very often lead to project failure. Thus, we argue that, to improve the companies’ competitiveness when developing new products, cooperation between processes related to system development and project management is key to achieving performance and success. This article presents arguments that tend to support this assertion and introduces an ongoing project to develop both a method and tool that aim to integrate both domains.

A wireless miniature ignition system has been developed for secure micro ignition applications. The power and data are transmitted using electromagnetic radio frequency waves between two closely coupled coils. The distance between the two coils is of 200 μm. High frequency (13.56 MHz) has been used enabling us to use coils made with PCB technology with only three copper wires with a separation between turns of 120 μm. A fully integrated prototype has been built and tested. It is 3 mm thick and has a section area close to 40 mm 2 (7 mm of diameter). When the command occurs, the system assures the application of enough electrical power (150 mW) to ignite a pyrotechnical powder in contact with the resistor of the ignition system. The measured electromagnetic energy transfer efficiency is up to 50% in normal environmental conditions (air surrounded). The difference between the experimental electromagnetic energy transfer efficiency and model prediction (67%) is due to bad coupling. The implemented solution to increase the electromagnetic energy transfer efficiency is to surround the coils with a magnetic polymer: it increases the energy transfer efficiency up to 72% in the air.

We proposed a safe MEMS pyrotechnical igniter made of one micro igniter and three single-use electrothermal micro switches. One ON–OFF micro switch is used to arm the pyrotechnical initiator. One OFF–ON micro switch is used to disarm the pyrotechnical initiator by cutting its electrical connections from the power supply. A second ON–OFF micro switch definitively removes the pyrotechnical initiator's ignition capability. Switches are based on electrothermal mechanisms and consist in breaking one electrical connection (ON–OFF switching), or micro soldering locally two electrical connections (OFF–ON switching). The ON–OFF switching based on the decomposition of GAP energetic material requires 500 mW during 30 ms. The OFF–ON switch using a O350 µm Sn/Pb ball requires a minimum of 200 mW during 5 s to create a good intermetallic layer and therefore a good electrical contact. The fabrication process of both switches and igniter is based on classic MEMS technology steps including LPCVD, PECVD, copper electro deposition and plasma etching steps. Fabrication yield reaches 99%.

This paper explores the interest to join system design and project management methods and tools. Our motivation is to prevent the obvious incompatibilities between technical objectives and socio-economical requirements in the enterprise. What we recommend is to work on a generic unique model based on the classical top down design steps, to which costs models and non-functional requirements are associated. Project management thus appears as an activity of diagnosis and optimisation, allowing to choose certain realisations between the different possible scenarios and to optimise the management by an allocation of tolerances, which is calculated for each supplier on the base of a global objective. This analysis concludes on the interest of two complementary tools : the evolutionary algorithms to arbitrate the scenarios, and the Monte-Carlo methods for the allocation of tolerances.

Electrical circuits can behave quantum mechanically when decoherence induced by uncontrolled degrees of freedom is sufficiently reduced. Recently, different nanofabricated superconducting circuits based on Josephson junctions have achieved a degree of quantum coherence sufficient to allow the manipulation of their quantum state with NMR-like techniques. Because of their potential scalability, these quantum circuits are presently considered for implementing quantum bits, which are the building blocks of the proposed quantum processors. We have operated such a Josephson qubit circuit in which a long coherence time is obtained by decoupling the qubit from its readout circuit during manipulation. We report pulsed microwave experiments which demonstrate the controlled manipulation of the qubit state.

The development of a lumped parameter model is described for the performances prediction of a solid propellant micro-scale rocket. A micro-scale rocket consists of a combustion chamber containing the propellant, a converging and a diverging part to accelerate the gas generated by the propellant combustion. The input modelling parameters are the geometrical features of the rockets, the propellant characteristics and the ambient conditions. The output results are the temperature, the pressure, the volumic mass of the gas in the combustion chamber and the resulting thrust as a function of time. To illustrate the computational results, the performances of one micro-rocket investigated at LAAS for micro-propulsion application have been evaluated. The micro-rocket has a throat diameter of 108 μm, a chamber diameter of 850 μm, a chamber length of 1500 mm, a convergent length of 500 μm and a diverging length of 500 μm. The computational results give a chamber pressure of ∼5 bar and a thrust value of ∼3 mN at steady state. To illustrate the capabilities of the model, Section 3.3 discussed two points: • The influence of the heat loss on the thrust force; • The influence of the diverging part design on the thrust force. Results show that the divergent length has an interest and must be optimised when the external pressure is closed to vacuum, whereas the diverging part length has no effect on the thrust results when the external pressure is atmospheric.

The integration of propellant within a silicon micromachined systems enables the realization of a new class of MEMS devices called microscale rocket. These new devices seem to respond to a real need in the field of high energetic microscale actuation. Their main originality is the use of only one solid propellant loaded in a small tank micromachined in a ceramic or silicon substrate. The structure consists of a sandwich of three micromachined silicon substrates: nozzles, igniters and propellant chambers. The thrust force issued from the combustion of the solid propellant ranges from 1 mN to a few mN. Just by geometrical and dimensional considerations, it is possible to adapt the thrust impulse depending on the application requirements. One identified application of microrockets is space with the realization of microscale thrusters for the control of the attitude or/and the station keeping of very small satellite. In a first part of the paper, we present the process of fabrication and the assembling of microthrusters as well as the specific equipment developed to load the solid propellant into microcavities. On a second part, we present briefly the modeling tools developed to predict the thruster performances.

We have used the kinetic Monte Carlo technique to investigate the intermixing mechanisms during the heteroepitaxial growth of semiconductors. We have shown that the temperature increases the intermixing between the substrate and deposited film, while an increasing growth rate inhibits this intermixing. We have also observed that intermixing is reduced when the energetics becomes unfavorable, i.e. with high lattice mismatches or hard-deposited materials.

We discuss a qubit circuit based on the single Cooper-pair transistor (which consists of two ultrasmall Josephson junctions in series) connected in parallel with a large Josephson junction. The switching of this junction out of its zero-voltage state is used to readout the qubit. We report measurements of the discriminating power of the readout process, and we discuss its back-action on the qubit.

Driver drowsiness is a major cause of traffic crashes all over the world. The real time detection and assessment of driver impairment through non-intrusive driver drowsiness detection system is a real challenge. Within this paper a quick overview of former development related with driver monitoring system is given. Then latest developments and results concerning sensing capabilities and diagnostic are presented. Finally some promising results are presented.

We have developed and measured a high-gain quantum-limited microwave parametric amplifier based on a superconducting lumped LC resonator with the inductor L including an array of 8 superconducting quantum interference devices (SQUIDs). This amplifier is parametrically pumped by modulating the flux threading the SQUIDs at twice the resonator frequency. Around 5 GHz, a maximum gain of 31 dB, a product amplitude-gain x bandwidth above 60 MHz, and a 1 dB compression point of -123 dBm at 20 dB gain are obtained in the non-degenerate mode of operation. Phase sensitive amplification-deamplification is also measured in the degenerate mode and yields a maximum gain of 37 dB. The compression point obtained is 18 dB above what would be obtained with a single SQUID of the same inductance, due to the smaller nonlinearity of the SQUID array., 7 pages, 4 figures, 23 references

Product Lifecycle Management (PLM) tools are widely used by the industry. However, they are not sufficient to guarantee the success of projects and too many projects still fail. Industrial groups have argued that these failures may be related to the managerial techniques used. Indeed organizational processes are more or less specifically mentioned in Systems Engineering (SE) standards but in practice project managers tend to rely more on their own standards which sometime set forth practices not in line with those of the SE domain, hence the reported discrepancies which very often lead to project failure. Thus to improve the companies' competitiveness when developing new products, cooperation between processes related to system development and Project Management (PM) is key to getting performance and success. This paper presents arguments which tend to support this theory and introduces an ongoing project of method and tool that aim at integrating both domains.

We report the efficient coupling of a $50\,\Omega$ microwave circuit to a high impedance conductor. We use an impedance transformer consisting of a $\lambda/4$ co-planar resonator whose inner conductor contains an array of superconducting quantum interference devices (SQUIDs), providing the resonator with a large and tunable lineic inductance $\mathcal{L}\sim 80 \mu_0$, resulting in a large characteristic impedance $Z_C\sim 1\,\mathrm{k}\Omega$. The impedance matching efficiency is characterized by measuring the shot noise power emitted by a dc biased high resistance tunnel junction connected to the resonator. We demonstrate matching to impedances in the $15$ to $35\,\mathrm{k}\Omega$ range with bandwidths above $100\,\mathrm{MHz}$ around a resonant frequency tunable in the $4$ to $6\,\mathrm{GHz}$ range., Comment: Published in Applied Physics Letters

With the development of microspacecraft technology micropropulsion concepts are introduced for course correction and orbit insertion as well as attitude control of the microspacecraft. In this context, we have introduced a new concept of MEMS-based technology microthruster responding to the spatial constraints (volume constraints, high level of integration) and MEMS characteristics (miniaturization, low cost, mass production). The originality of these new thrusters is the use of only one solid propellant loaded in a small tank micromachined in a ceramic, glass or silicon substrate and the fabrication of arrays of N independent microthrusters in the same chip. The structure consists of a sandwich of three micromachined silicon substrates: nozzles, igniters and propellant chambers. The thrust force generated can be set from a few hundred µN to a few tens of mN by geometrical and dimensional considerations. In this paper we present the fabrication and assembly of one prototype: it is an array of 36 microthrusters that proved the technological feasibility of this new concept of small-scale thrusters. We also investigate the influence of nozzle geometry on the performances of our thruster.

Using the Monte Carlo technique, we have developed a model for the Atomic Scale Simulation of the formation of extended defects under irradiation by means of a personal computer. Three types of reactions are assumed to take place: vacancy-interstitial recombination, association of point defects to form a new extended defect, point defect-extended defect reaction leading to the growth of extended defects. Periodic boundary conditions are used to simulate an infinite lattice and the surface effect is not considered. The results are compared with those obtained by using the chemical rate theory and with experimental data on CdTe. It is shown that atomic scale simulation may leads to microscopic results that cannot be reached by solving the usual sets of equations. In particular, the spatial distribution of dislocation loops, in agreement with TEM experimental observations, and the indications about the distribution of vacancies around the dislocation loops. It is also shown that a strong correlation exists between the relative positions of extended defects and point defects and that they influence one another.

We have performed atomic scale simulations of heteroepitaxial growth of thin films using the valence force field approximation and Monte Carlo techniques. The case of CdTe/(001)GaAs is considered. Our simulations indicate valley formation presenting (111) facets with unstable bottoms in the early stages of the growth. This roughening is a source of dislocation, as it appears to relax the elastic energy of the deposited layers by formation of V-grooves. We have used a calculated RHEED as an in situ control of deposited layers. Finally, we present the influence of an imperfect surface in the morphology of the deposited films.

MEMS-based microthrusters are now introduced and fabricated to meet micropropulsion requirements especially for the attitude control of the nanosatellites. The key to the development of these microsystems lies in the generation of extremely accurate thrust level. This is made possible by modelling tools capable of predicting the processes inside the thruster during the subsonic combustion and of computing the theoretical performance of the systems. In this paper, we present a new model based on the computation of the unsteady gas flow inside the microthruster. The results show the evolution of the gas pressure, velocity and gas volume at each section of the thruster and at each step in the propulsion process. The final aim of this study is to obtain a model package capable of predicting the level of the exhaust thrust of any subsonic microthruster for any given geometrical features. For a glycidyle azide polymer (GAP)-based microthruster, the calculations yield the best subsonic micronozzle design: the divergent length ranges from three to seven times the throat radius for a divergence angle of 12°. The chamber-to-throat section ratio must be comprised between 5 and 10. Modelling results also show that, for a 4-mm combustion diameter thruster, the thrust force ranges from 2.5 to 75 mN, depending on geometrical characteristics.

In this paper, we investigate the modeling of dry silicon thermal oxidation in the light of the model capabilities and the trends in microelectronics. We show how a combined use of different models can be made in a way to generate process simulations that are strongly related to microscopic physical phenomena. In conjunction with experimental literature data, first principle calculations have been carried out with the objective of isolating some elementary oxidation mechanisms, i.e. basic atomic movements and their corresponding activation energies. This preliminary list of mechanisms is discussed in detail. A growth mechanism allowing the oxide defect generation is proposed. We then present Monte Carlo calculations with the implemented mechanisms where at least three silicon layers are oxidized. Finally, we introduce a macroscopic formulation of these mechanisms via the Chemical Rate Theory.

We have performed an atomic-scale simulation of (100) thin films heteroepitaxial growth of semiconductors with zincblende structure by associating a Monte Carlo technique with an energy model based on the valence force field approximation. It is shown that grooves showing (111) facets are formed in the early stages of the growth owing to enhanced interlayer migrations. The strain relief can be achieved within a few atomic layers, in agreement with experimental observations.

This paper presents a new hybrid diagnostic methodology. This new hybrid system involves statistical pre-processing, Artificial Neural Networks (ANN) and Fuzzy Logic (FL). The statistical pre-processing of data allows outliers to be eliminated (filtering) and dimensional reduction while keeping the most important data. Then, each process state is learned by one of the original constructive algorithms discussed: Multidimensional Fuzzy Sets (MFS) which fuzzyfies binary ANN or Generalized Radial Basis Functions (GRBF) learned by the Estimation Maximization (EM) algorithm. The final step is the final decision by Fuzzy Logic algorithms, in which an automatic defuzzification method is proposed. These methodologies produce some parameters which allows real-time to be performed.

This paper presents a new technique for thinning down up to 10 m and handling various semiconductor devices, and transferring them onto host substrates. An optimized mechanical lapping is used to remove the wafer backside after the fabrication process by way of a cavity-wafer. The original transfer technique based on the different thermal properties of waxes or epoxy layers is described, and the electrical results obtained on test devices are presented.

In this paper, we present a new way to perform actuation through the use of forces produced by pyrotechnic combustion. After describing the functioning of this so-called pyrotechnic actuator, we present the modelling of the combustion ignition in order to find an optimal ignition system enabling minimization of ignition energy. Good agreement between experience and simulation is obtained and characterizations of the pyrotechnic actuator give an idea of its performances in terms of gas yield and forces developed. The low cost and the use of a classic microtechnology process as well as the excellent ratio between the energy produced over the power consumption give good prospects for these actuators.

In this paper, the diagnostic part of the SAVE system is described. It is composed of three main diagnostic subsystems 1) behavioural diagnosis, 2) physical diagnosis and 3) critical diagnosis. Each subsystem uses different sensors on-board the vehicle and the information is placed in a hierarchical order and mixed to obtain a general diagnosis. A model (black-box), learned off line, is compared on line to the actual driver's performance. Owing to the inherent difficulty of this problem, the model is created by using Statistical and Artificial Intelligence algorithms (Neural Networks and Fuzzy Logic). Laboratory experiments were made and yielded a success rate in excess of 95%. On-line experiments have started using the SAVE demonstrators in which the system is able to differentiate between the driving behaviour of two persons with a success rate of 98% under the same real traffic conditions.

There is considerable interest in thin-film microheaters for decreasing the power consumption in portable applications. In this paper, we present the study of new stacked thin membranes (SiO 2 /SiN 1.2 ) supporting the heating element (polysilicon resistor). The great interest of using SiN 1.2 deposited onto a SiO 2 layer is the improvement in mechanical properties of the membrane, leading to a fabrication yield very close to 100%. Microheaters fabricated with a 1.6 mm × 1.6 mm square and 0.7 μm thick SiO 2 /SiN 1.2 membrane give promising results in terms of power consumption; 230°C is reached with an electrical power of 50 mW.

Achieving individual qubit readout is a major challenge in the development of scalable superconducting quantum processors. We have implemented the multiplexed readout of a four transmon qubit circuit using non-linear resonators operated as Josephson bifurcation amplifiers. We demonstrate the simultaneous measurement of Rabi oscillations of the four transmons. We find that multiplexed Josephson bifurcation is a high-fidelity readout method, the scalability of which is not limited by the need of a large bandwidth nearly quantum-limited amplifier as is the case with linear readout resonators., 7 pages, 6 figures, and 31 references

Part 1: Knowledge Discovery and Sharing; International audience; This paper puts forward several evolutions in methodological approaches to « project management». Firstly, it aims to bring closer the founding models of different engineering approachesincluding systems engineering and project management recommendations to allow fora greater continuity and enhanced management coherence,from beginning to end of the project. It focuses on operating a generic process, called DECWAYS, based on handling management requirements:(1)analyze the requirements to arrive at a complete inventory of the final product ;(2)associate with each one of these requirements ,an « indicator » setting a target objective for completion, supplemented by a risk function detailing the risk at hand based on the deviation relative to this target objective; (3)share and allocate the responsibility for requirements follow-up between the project team leaders; (4) organize and coordinate the follow up of these indicators throughout the product development as proof of a good work management and,(5) finally, validate the total completion of the target objectivesthrough the final prediction/completion conformity of these indicators. Based on this, several operational recommendations are explained and the practicality of DECWAYS embodying these principles is demonstrated using an experimental example for the design/planning of an electronic key.

In this paper, we model first the heating performance of a silicon micromachined microheater. The pros and cons of the use of a stacked dielectric membranes instead of p ++ -Si membranes are discussed, either in terms of electrical consumption, or in terms of emperature homogeneity. Then, we realize and characterize two examples among the simulated structures. This allows some practical problems during the fabrication, essentially due to mechanical breakdown, to be demonstrated. A general agreement between results is found. This study shows significant promise in the development of stacked dielectric membranes.

We have investigated the kinetics of heteroepitaxial growth with large lattice mismatch by associating the Monte Carlo technique with an energy model based on valence force field (VFF) approximation. The energy model allows the acceleration of the atomic motions as a function of local strain energy and a relaxation of most stressed positions. We have observed the roughening of the surface followed by the formation of (111) facets, the apparition of highly mobile atoms in interstitial positions on these facets and the reaction between these atoms. The reactions are seen to lead to stabilized nuclei with dangling bonds which are at the origin of point defects or extended defects in the growing layer.

Once the in board smart multisensor danger detection copilot system defined (1992). LAAS-CNRS has investigated different methodological approaches to realise the diagnosis. Three complementary directions have been identified : a. The following of the driving mistakes in terms of trafiic regulations (1992); b. The evaluation time of the reactivity capability of the driver. We have studied Autoregressive Moving Average (ARMA), (1993) and c. The driving procedural analysis on which we are working in this contribution (1994). We are now planning to introduce a pre-metric by Principal Component Analysis (PCA). Experiment : A driver realises several times the experiment which consists of negotiating a cross-roads.

We report results of atomic scale simulations used to study the dynamics of epitaxial growth of GaAs and, in particular, the oscillations of the photoemission current. We have simulated growth of GaAs using a monoatomic As source. The photoemission oscillations are found to depend on the growth conditions in the same manner as do reflection high-energy electron diffraction (RHEED) intensity oscillations.