Добірка наукової літератури з теми "Principe de compensation des perturbations"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся зі списками актуальних статей, книг, дисертацій, тез та інших наукових джерел на тему "Principe de compensation des perturbations".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Статті в журналах з теми "Principe de compensation des perturbations"
1
Jeltsch-Thömmes, Aurich, and Fortunat Joos. "Modeling the evolution of pulse-like perturbations in atmospheric carbon and carbon isotopes: the role of weathering–sedimentation imbalances." Climate of the Past 16, no. 2 (March 4, 2020): 423–51. http://dx.doi.org/10.5194/cp-16-423-2020.
Повний текст джерелаАнотація:
Abstract. Measurements of carbon isotope variations in climate archives and isotope-enabled climate modeling advance the understanding of the carbon cycle. Perturbations in atmospheric CO2 and in its isotopic ratios (δ13C, Δ14C) are removed by different processes acting on different timescales. We investigate these differences on timescales of up to 100 000 years in pulse-release experiments with the Bern3D-LPX Earth system model of intermediate complexity and by analytical solutions from a box model. On timescales from years to many centuries, the atmospheric perturbations in CO2 and δ13CO2 are reduced by air–sea gas exchange, physical transport from the surface to the deep ocean, and by the land biosphere. Isotopic perturbations are initially removed much faster from the atmosphere than perturbations in CO2 as explained by aquatic carbonate chemistry. On multimillennial timescales, the CO2 perturbation is removed by carbonate compensation and silicate rock weathering. In contrast, the δ13C perturbation is removed by the relentless flux of organic and calcium carbonate particles buried in sediments. The associated removal rate is significantly modified by spatial δ13C gradients within the ocean, influencing the isotopic perturbation of the burial flux. Space-time variations in ocean δ13C perturbations are captured by principal components and empirical orthogonal functions. Analytical impulse response functions for atmospheric CO2 and δ13CO2 are provided. Results suggest that changes in terrestrial carbon storage were not the sole cause for the abrupt, centennial-scale CO2 and δ13CO2 variations recorded in ice during Heinrich stadials HS1 and HS4, though model and data uncertainties prevent a firm conclusion. The δ13C offset between the Penultimate Glacial Maximum and Last Glacial Maximum reconstructed for the ocean and atmosphere is most likely caused by imbalances between weathering, volcanism, and burial fluxes. Our study highlights the importance of isotopic fluxes connected to weathering–sedimentation imbalances, which so far have been often neglected on glacial–interglacial timescales.
2
Sun, Tao, Panfeng Wang, Binbin Lian, Sida Liu, and Yapu Zhai. "Geometric accuracy design and error compensation of a one-translational and three-rotational parallel mechanism with articulated traveling plate." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 232, no. 12 (February 1, 2017): 2083–97. http://dx.doi.org/10.1177/0954405416683433.
Повний текст джерелаАнотація:
The demands for advanced and flexible docking equipment are increasing in the fields of aerospace, shipbuilding and construction machinery. Position and orientation accuracy is one of the most important criteria, which would directly affect the docking quality. Taking a novel one-translational and three-rotational docking equipment, referred to as PaQuad parallel mechanism as example, this article proposed an accuracy improvement strategy by geometric accuracy design and error compensation. Drawing mainly on screw theory, geometric error modeling of PaQuad parallel mechanism was first carried out via four independent routes. Joint perturbations and geometric errors were included in each route error twist. Wrenches due to articulated traveling plate were applied to eliminate joint perturbations. Then, geometric accuracy design was implemented at component and substructure levels. The basic principle was to transfer geometric errors into dimensional or geometric tolerance. High-precision machining/assembling techniques were applied to satisfy the tolerance. Finally, error compensation resorting to kinematic calibration was implemented at mechanism level. It can be summarized as identification modeling, measurement planning, and parameter identification and modification. Maximum deviations of PaQuad parallel mechanism before calibration experiment were 0.01 mm, [Formula: see text], [Formula: see text], and [Formula: see text]. And they become 0.01 mm, [Formula: see text], [Formula: see text], and [Formula: see text] after kinematic calibration. Orientation accuracy of PaQuad parallel mechanism has improved one order of magnitude. It proves the effectiveness of accuracy improvement in terms of geometric accuracy design and error compensation.
3
Tang, Peng, Yuehong Dai, and Junfeng Chen. "Nonlinear Robust Control on Yaw Motion of a Variable-Speed Unmanned Aerial Helicopter under Multi-Source Disturbances." Aerospace 9, no. 1 (January 15, 2022): 42. http://dx.doi.org/10.3390/aerospace9010042.
Повний текст джерелаАнотація:
This paper studies the multi-source disturbances attenuation problem on the yaw motion of unmanned aerial helicopter with a variable-speed rotor. The yaw motion subsystem dominated by an electrically-driven tail rotor is firstly introduced, and its trajectory accuracy requires particularly close attention. To this end, we establish a fourth-order yaw error dynamic equation; subsequently, a nonlinear robust control scheme based on optimal H∞ principle is developed, consisting of laws of virtual functions, parameter estimation and a compensation signal. The novelty of this scheme lies in unifying the techniques to deal with the uncertain parameters, noise perturbations, actuator output fault and external airflow turbulence into a simple framework. Stability analysis guarantees that the yaw closed-loop system has the predefined performance of disturbance suppression in the sense of a finite L2-gain. Comparison results with the extended state observer based backstepping controller verify the effectiveness and superior performance of proposed scheme in an aircraft prototype.
4
Grudinin, Viktor S., Valeriy S. Khoroshavin, Alexander V. Zotov, and Sergey V. Grudinin. "Adaptive Iterative Control of Temperature in Greenhouse." Engineering Technologies and Systems 29, no. 3 (September 30, 2019): 383–95. http://dx.doi.org/10.15507/2658-4123.029.201903.383-395.
Повний текст джерелаАнотація:
Introduction. Creation and development of efficient agricultural complexes providing high yields at minimal time, material, and energy costs is impossible without the use of automatic control systems (ACS), which allow for maintaining the microclimate of the greenhouse with high accuracy. Improvements of the microclimate by ASC are aimed at neutralizing the influence of parametric perturbations of processes inside and outside the greenhouse. Using the example of a temperature control channel in a greenhouse with a heating circuit based on hot piped water supply, an adaptive iterative (search) algorithm for adjusting the components of a proportional-integral-differential (PID) controller in the heating circuit is proposed to ensure the required quality of the control process. Materials and Methods. The management is based on a parametrically uncertain model of temperature in the greenhouse, the structure of which, based on the principle of superposition, is transformed into a form with control and disturbances concentrated on an output coordinate. The use of an adaptive PID controller is based on the real-time analysis of a database containing trends of the controlled process. Using operators of Database Managment System or SQL language, queries evaluate regulation quality in accord with quality assessment. Proportional and differential components of the PID controller are adjusted so that the control system works on the verge of switching to auto-oscillation mode. The resulting static error is compensated by a change in the driving force. Results. Simulation of the real structure of a single-circuit automatic control system with temperature in the greenhouse with built-in regulating, executive and measuring elements, with a delay of a coolant movement was carried out using the software MVTU (SimIn- Tech). The proposed adaptation algorithm, consisting of the additive adjustment of the PID controller coefficients and being conveniently implemented within the SCADA system, was shown to provide the minimum oscillatory temperature maintenance for arbitrary parametric perturbations in the presence of the delay. Discussion and Conclusion. The proposed adaptation algorithm provides for compensation for model uncertainty and disturbances, while achieving the required accuracy of maintaining the temperature in the greenhouse. Results of the study will serve as the basics for development of multi-contour ACS microclimate greenhouses with the examination of the impact and compensation of parametric and structural uncertainty, inertia and nonlinearities of real elements. Our results may be used in many sectors of the national economy to study the general and applied problems of digital adaptive process control.
5
Gottlieb, G. L., and G. C. Agarwal. "Compliance of single joints: elastic and plastic characteristics." Journal of Neurophysiology 59, no. 3 (March 1, 1988): 937–51. http://dx.doi.org/10.1152/jn.1988.59.3.937.
Повний текст джерелаАнотація:
1. Step changes in torque were applied to the elbow or ankle joint of normal human subjects who exerted constant levels of effort. They were instructed to not react to the torque but to allow their limbs to move to a new equilibrium position. In this experimental paradigm, the joint may be characterized by a nonlinear compliant element. The aim of this study was to characterize the elastic properties of the compliant element. 2. Joint elasticity is described by an S-shaped relation between torque and angle (a "compliant characteristic curve"). The stiffness of a joint is greatest for small perturbations and decreases as the size of the perturbation is increased whether the limb is loaded or unloaded from its initial equilibrium. 3. The S shape of the compliant characteristic curve is relatively constant when measured at different initial joint angles from the same initial joint torque. 4. Higher levels of initial muscle torque increase the steepness of the compliant characteristic curve. 5. All changes in initial joint torque and angle preserve the S shape. The inflection point of the characteristic curve is always at the initial equilibrium angle and torque. This shifting of the inflection point of the torque-angle relation implies a fundamental plasticity in joint compliance. The elastic component is not invariant but changes with the joint's initial equilibrium state. 6. Changes in muscle tension and length that result from a perturbation are accompanied by changes in muscle activation. The relationship between perturbation torque and mean equilibrium EMG is similar to that found for voluntary isometric contraction. It is not possible to conclude what proportion of the late EMG response to perturbation is mediated by segmental reflex mechanisms. 7. At the levels of torque used here, changes in joint stiffness are highly correlated with changes in tonic contraction of the muscle opposing the load. This change in stiffness is not the result of antagonist coactivation, which was minimal. 8. The compliant characteristic curves of elbow and ankle are qualitatively similar. The principal difference is due to the greater passive stiffness of the ankle. 9. Our findings are inconsistent with aspects of the theory of invariant characteristics or with models of movement and load compensation that postulate a control scheme based only on the setting of muscle and reflex equilibrium points. The data are also incompatible with models that only control the elastic stiffness of the muscle.
6
Choe, Keith P. "Physiological and molecular mechanisms of salt and water homeostasis in the nematode Caenorhabditis elegans." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 305, no. 3 (August 1, 2013): R175—R186. http://dx.doi.org/10.1152/ajpregu.00109.2013.
Повний текст джерелаАнотація:
Intracellular salt and water homeostasis is essential for all cellular life. Extracellular salt and water homeostasis is also important for multicellular organisms. Many fundamental mechanisms of compensation for osmotic perturbations are well defined and conserved. Alternatively, molecular mechanisms of detecting salt and water imbalances and regulating compensatory responses are generally poorly defined for animals. Throughout the last century, researchers studying vertebrates and vertebrate cells made critical contributions to our understanding of osmoregulation, especially mechanisms of salt and water transport and organic osmolyte accumulation. Researchers have more recently started using invertebrate model organisms with defined genomes and well-established methods of genetic manipulation to begin defining the genes and integrated regulatory networks that respond to osmotic stress. The nematode Caenorhabditis elegans is well suited to these studies. Here, I introduce osmoregulatory mechanisms in this model, discuss experimental advantages and limitations, and review important findings. Key discoveries include defining genetic mechanisms of osmolarity sensing in neurons, identifying protein damage as a sensor and principle determinant of hypertonic stress resistance, and identification of a putative sensor for hypertonic stress associated with the extracellular matrix. Many of these processes and pathways are conserved and, therefore, provide new insights into salt and water homeostasis in other animals, including mammals.
7
Cline, T. W. "Evidence that sisterless-a and sisterless-b are two of several discrete "numerator elements" of the X/A sex determination signal in Drosophila that switch Sxl between two alternative stable expression states." Genetics 119, no. 4 (August 1, 1988): 829–62. http://dx.doi.org/10.1093/genetics/119.4.829.
Повний текст джерелаАнотація:
Abstract The primary signal for Drosophila sex determination is the number of X chromosomes relative to the number of sets of autosomes. The present report shows that the numerator of this X/A signal appears to be determined by the cumulative dose of a relatively limited number of discrete X-linked genetic elements, two of which are sisterless-a and sisterless-b. This discovery regarding the nature of the sex determination signal grew out of previous studies of both the likely X/A signal target (the feminizing switch gene, Sex-lethal) and two positive regulators of that target gene (sis-a and daughterless). Combinations of genetic perturbations in these three genes had been shown to have synergistic effects. A model proposed in part to account for these interactions generated a large variety of strong predictions for sex-specific synergistic interactions that would be diagnostic for X/A numerator elements and could distinguish them from other components of the sex determination system. All these predictions, as well as other predictions for X/A numerator elements, are shown here to be fulfilled. The most compelling observations involve sexually reciprocal viability effects of duplications of wild-type genes: combinations of sis-a+, sis-b+ and/or Sxl+ duplications are lethal to males but rescue females from the otherwise lethal effects of changes in other components of the sex determination machinery. The many interactions described here illustrate an important principle that may seem counter-intuitive: perturbations of the sex determination signal for Drosophila generally will not appear to affect adult sexual phenotype. This principle follows from the fact that Sxl is involved in dosage compensation as well as sex determination, and from important aspects of the nature and timing of Sxl's regulation both by the X/A signal and by Sxl's own products (positive autoregulation). These factors mask potential effects on adult sexual differentiation by causing the premature death of cells and/or individuals. The fact that the vast array of results presented here conform to this principle is strong evidence in favor of a "binary state" model for Sxl regulation by the X/A signal. This model is favored over an alternative "multiple state" hypothesis that was proposed by others in a different study of the X/A signal. In that same study it was concluded that region 3E8-4F11 of the X chromosome contained especially potent X/A numerator elements.(ABSTRACT TRUNCATED AT 400 WORDS)
8
Kanbur, Ravi. "Économie du développement et principe de compensation." Revue internationale des sciences sociales 175, no. 1 (2003): 29. http://dx.doi.org/10.3917/riss.175.0029.
Повний текст джерела
9
Limarchenko, O., O. Nefedov, and O. Sirenko. "VERIFICATION OF THE CONTROL ALGORITHM FOR RESERVOIRS WITH LIQUID BASED ON THE COMPENSATION OF THE FORCE RESPONSE IN DIFFERENT RANGES OF MANIFESTATION OF NONLINEARITIES." Bulletin Taras Shevchenko National University of Kyiv. Mathematics Mechanics, no. 1 (41) (2020): 51–56. http://dx.doi.org/10.17721/1684-1565.2020.01-41.12.51-56.
Повний текст джерелаАнотація:
Problem about motion of a reservoir with liquid with a free surface is considered based on the compensation of a force response of the liquid on reservoir walls. Such an approach is selected since usual methods of control of mechanical system motion are mostly intended for linear systems of relatively small dimension. However, models of dynamics of the combined motion of reservoirs with liquid are described with relatively high-dimensional nonlinear systems ordinary differential equations. For obtaining the mathematical model of combined motion of a reservoir with liquid with a free surface we use the Hamilton–Ostrogradskiy variational principle, for which it is possible to determine analytically all internal forces of interaction of system component parts. Namely using this algorithm, we determine the main vector of forces of the liquid pressure on reservoir walls (force response of liquid). The algorithm of the motion control of the reservoir with liquid is based on the inclusion of the compensation of the liquid force response to controlling actions, this reduces the motion of the system reservoir–liquid, where the effect of forces from oscillating liquid on the reservoir motion is eliminated. This algorithm was tested for problems of impulse and vibration disturbance of the translational motion of the system in the horizontal plain. We consider the disturbance of the system motion by a force rectangular impulse applied to the reservoir wall, the duration of the impulse is lesser than a quarter of the period of a liquid free oscillations according to the first normal mode. Amplitudes of the impulse were selected with the purpose of analysis of the behavior of the controlled system in different ranges of manifestation of nonlinearities. We state the problem to verify the accuracy of this algorithm for three ranges of manifestation of nonlinear properties in the system, namely, for the linear range (amplitudes of waves on a free surface h do not exceed 0,1 of the radius of a free surface ( <0,1R); for the weakly nonlinear range ( <0,2R) and for the strongly nonlinear range with maximum amplitudes of waves about =0,32R. Numerical modeling enables the determination of errors of developed algorithm, which does not exceed 0,5 %, although they insignificantly increase with the increase of amplitudes of oscillations on a free surface of liquid. At the same time perturbations on a free surface of liquid for the controlled motion are always greater than for the uncontrolled motion.
10
Neufeld, Chris, Pascal van Lieshout, and David Purcell. "Articulatory compensation to second formant perturbations." Journal of the Acoustical Society of America 133, no. 5 (May 2013): 3342. http://dx.doi.org/10.1121/1.4805647.
Повний текст джерелаДисертації з теми "Principe de compensation des perturbations"
1
Qaraai, Youssef. "Compensation des perturbations étalables et contrôle protecteur des zones vulnérables." Perpignan, 2008. http://www.theses.fr/2008PERP0819.
Повний текст джерелаАнотація:
Cette thèse concerne l'étude de quelques concepts introduits dans le cadre de l'analyse régionale des Systèmes à Paramètres Distribués. En particulier, les problèmes de compensation des perturbations étalables et protection des zones vulnérables y sont traités. Lorsqu'un système distribué subit une perturbation étalable, certaines zones données (vulnérables) peuvent être atteintes par les effets de cette perturbation. Pour de telles zones nous montrons, en un premier temps, comment remédier à ces effets lorsque celles-ci sont atteintes. Ensuite, nous considérons le problème du contrôle protecteur qui consiste à pouvoir protéger de telles zones avant qu'elles ne soient atteintes. Plusieurs caractérisations de ces deux types de contrôles (remédiable et protecteur) sont données. Les résultats obtenus pour les systèmes linéaires, sont étendus à une certaine classe de systèmes distribués non linéaires. Pour illustrer ces concepts, quelques exemples et applications sont considérésThis thesis is related to the study of some concepts introduced in the regional analysis of distributed parameters systems. Particularly, problems of compensation of the spreadable disturbances and protection of the vulnerable areas are considered. When a distributed system undergoes a spreadable disturbance, some given zones (vulnerable) can be reached by the disturbance effect. For such a zones, we show in the first time, how to remedy at this effect when these zones are reached. Moreover, we consider the problem of protector control which consists in being able to protect such a zones before that they will be reached. Several characterizations of these two controls (remediable and protector) are given. The obtained results for the linear systems are extended to a class of nonlinear systems. To illustrate these concepts, some examples and applications are considered
2
Danion, Frédéric. "Compensation volontaire de perturbations dynamiques lors de mouvements rythmiques chez l'homme." Aix-Marseille 1, 1997. http://www.theses.fr/1997AIX11072.
Повний текст джерелаАнотація:
L'ensemble de ces travaux s'interesse aux problemes fondamentaux poses par les capacites d'adaptation intentionnelle des activites rythmiques, qui associees aux capacites d'adaptation reflexe, conferent leur efficacite a ces comportements. Pour etudier les capacites d'adaptation intentionnelle, nous avons eu l'idee d'associer deux protocoles : un premier, dit de compensation, qui consiste a maintenir un mouvement malgre un changement de force externe, et un deuxieme, dit de non-intervention, dans lequel le sujet doit se laisser faire (i. E. Ne pas resister). Le travail experimental comporte deux parties. La premiere partie est consacree a l'activite locomotrice pour son aspect hautement fonctionnel. Deux experiences ont ete realisees pour etudier les strategies mises en place par des sujets humains permettant de maintenir leur vitesse de marche 1) malgre une contrainte elastique posee entre la taille et le bout du pied (facilitant la flexion de la jambe) et, 2) malgre une resistance a l'avancement (facilitant la dissipation des forces propulsives) augmentant lineairement et durant 3 secondes. Dans la deuxieme partie, nous avons conserve notre interet pour la compensation en temps reel, mais cette fois-ci lors d'un mouvement rythmique du coude, plus simple du point de vue de son systeme effecteur. L'idee principale qui ressort de ce travail est que la compensation volontaire d'une perturbation mecanique peut s'effectuer de deux facons non exclusives : 1) grace a la plasticite de la synergie neuromusculaire, c'est-a-dire des moyens de production), et 2) grace a la plasticite des modes de controle du mouvement.
3
Diop, Sette. "Théorie de l'élimination et principe du modèle interne en automatique." Paris 11, 1989. http://www.theses.fr/1989PA112209.
Повний текст джерелаАнотація:
Deux questions d'automatique théorique sont abordées dans ce rapport : l'élimination et le principe du modèle interne. L'élimination consiste en la transformation d'une représentation d'un système où figure une variable latente en une représentation équivalente (c'est-à-dire du même système) où ne figure plus cette variable. Cette question a été longuement discutée dans la littérature consacrée aux systèmes linéaires constants par des auteurs comme J. C. Willems, H. Blomberg and R. Ylinen, H. H. Rosenbrock, etc. Nous montrons ici que la théorie algébrique différentielle de l'élimination permet de la résoudre presque complètement pour des systèmes aussi généraux que ceux descriptibles par des équations différentielles algébriques à coefficients (constants ou non) dans un corps différentiel de caractéristique nulle. Vues les considérations précédentes la théorie de l'élimination est en fait une technique clé qui peut être utile dans nombre d'autres questions d'automatique dès lors qu'il s'agit d'éliminer une variable arbitraire dans un système d'équations. En particulier, on établit le lien avec le principe du modèle interne. Ce dernier concerne, à l'origine, le classique problème de régulation. Il énonce une propriété de structure nécessaire de tout compensateur destiné à réguler un système sous une condition de régulation tenant compte de signaux de référence et de perturbation, appelés variables exogènes. Succinctement, on peut dire (l'énoncé précis est donné) qu'on montre que tout compensateur d'un système devant assurer une condition de régulation donnée, doit être tel que le système compensé contienne une copie du modèle des variables exogènes. Cette question a d'abord été étudiée par E. J. Davison, puis par W. M. Wonham ct ses collaborateurs. La méthode utilisée ainsi que les résultats que nous obtenons contribuent à éclairer cette théorie. Le résultat essentiel se réduit à un test qui peut être effectué grâce à la procédure d'élimination introduite auparavantThis report is concerned with two problems of control theory: elimination and internal model principle. Elimination consists of transforming a system representation with latent variable into another representation which no longer has a latent variable but which is equivalent to the previous representation, i. E. Which is of the same system. This question has been discussed at length in the literature concerned with constant linear systems by authors such as J. C. Willems, H. Blomberg and R. Ylinen, H. H. Rosenbrock, etc. We show that the differential algebraic elimination theory provides an almost complete solution to the problem for systems which can be described by differential algebraic equations with constant or non-constant coefficients in a differential field of characteristic zero. After dealing with the above question, we note that elimination theory is a key-tool which may serve to solve other control theory problems, since the basic problem is to eliminate an arbitrary variable in a system of equations. This is especially the link with the internal model principle. The latter is initially concerned with the standard regulator problem. It states a necessary structure property of any compensator designed to regulate a system under some regulation condition invoking reference and disturbance signals, called exogenous variables. Roughly, we may say that any compensator which satisfies a regulation condition must be such that the compensated system contains a copy of the exogenous variable model (the exact statement is given). This question has been addressed by E. J. Davison, W. M. Wonham et al. Our method and results improve on this theory. The main result can be reduced to a test which can be made by means of the previous elimination procedure
4
Riopel, Mathieu. "Mise en fonction d'un spectromètre HREELS basé sur le principe de compensation de la dispersion." Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25077/25077.pdf.
Повний текст джерела
5
Pradels, Grégory. "Etalonnage en orbite d'accéléromètres ultrasensibles pour un test du Principe d'Equivalence à 10-15." Paris 6, 2003. http://www.theses.fr/2003PA066267.
Повний текст джерела
6
Moumeni, Abdelkader. "Étude d'un problème de perturbations singulières à propos d'une équation d'évolution non classique." Nancy 1, 1992. http://www.theses.fr/1992NAN10105.
Повний текст джерелаАнотація:
Dans ce travail, l'étude porte sur l'existence, et le comportement asymptotique, de la solution d'un problème d'évolution non classique qui entre dans la catégorie des problèmes dits problèmes de perturbations singulières, avec des conditions aux bords non usuelles. Ce problème régit les petites oscillations d'un système élastique constitué de deux milieux en interaction. Par exemple, une membrane élastique rectangulaire, fixée sur trois de ses cotés, le quatrième coté étant solidaire d'une tige élastique. On suppose que l'inertie de la membrane est négligeable par rapport à celle de la tige et l'on cherche alors un développement asymptotique du mouvement lorsque l'inertie de la membrane tend vers zéro. En d'autres termes, on cherche comment les vibrations de la membrane perturbent celles de la tige. On étudié également le comportement asymptotique des éléments propres d'un operateur perturbé qui intervient dans la formulation variationnelle du problème décrit ci-dessus. On montre qu'il existe deux groupes de valeurs caractéristiques tel que l'un tend vers les valeurs propres d'un problème classique (problème de Dirichlet) et l'autre vers les valeurs propres d'un problème non classique (les conditions aux bords sont données par des équations aux dérivées partielles)
7
Lombard, Latune Julie. "La compensation écologique : du principe de non perte nette de biodiversité à son opérationnalisation - analyse de l'action collective." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLA040/document.
Повний текст джерелаАнотація:
Titre : La compensation écologique : du principe de non perte nette de biodiversité à son opérationnalisation – analyse de l’action collectiveMots clés : Compensation écologique, action collective, effets spatio-temporels, Non perte nette de biodiversité.Résumé : En France la compensation écologique des impacts résiduels sur la biodiversité a pour objectif l'atteinte de la non perte nette de biodiversité. Un cadre normatif énonçant une dizaine de principes permet théoriquement d'atteindre cet objectif.Nous étudions donc la mise en œuvre de la compensation écologique à travers trois projets de LGV. Nous analysons le jeu d'acteur autour de cette mise en œuvre grâce aux théories de l'action collective, et notamment grâce au cadre analytique de la Traduction proposé par M. Callon. Cette première analyse nous permet de comprendre en quoi la compensation est un objet socio-technique. Nous mettons en évidence que de nombreux acteurs aux intérêts divergents se mobilisent pour mettre en place la compensation écologique. Nous montrons qu’il y a une tension entre la mobilisation des acteurs et les exigences écologiques, ces deux aspects ne sont pas toujours compatibles. La durée des cahiers de charges et la rétribution des propriétaires fonciers, chargés de la mise en œuvre de la compensation écologique est déterminante à la fois pour la mobilisation des humains et des nons humains (biodiversité). Nous nous interrogeons ensuite sur les effets spatiaux temporels de l’action collective et de sa capacité à tendre vers une non perte nette de biodiversité. Nous montrons que les mesures n’ont pas pu être effectives avant le démarrage des impacts. La gestion du foncier en France semble pour le moment difficilement compatible avec une mise en œuvre de la compensation non anticipée très en amont. Nous montrons que la majorité des sites de mesures de compensation sont de petites tailles, bien que des espaces de grandes tailles semblent davantage vertueux d’un point de vue écologique. Enfin nous montrons que la pérennité des mesures de compensations peut être appréhendée à différents niveaux suivant (i) le type de maîtrise foncière (acquisition, conventionnement); (ii) les contrats de mesures de compensation (durée, contenu de ces derniers – les sanctions en cas de manquement aux obligations influent sur le maintien des mesures) ; (iii) la gestion du renouvellement de ces contrats; (iv) la vocation des propriétaires des sites (une entreprises publique ou privée de construction n’a pas comme rôle au départ de conserver la biodiversité, tandis qu’une association naturaliste en a la vocation) ; (v) la pérennité des structures et les assurances quant au devenir des sites de mesures de compensation en cas de faillite; (vi) le suivi et le contrôle l’application de la compensationIn France, the objective of ecological compensation for residual impacts on biodiversity is to achieve no net loss of biodiversity. A normative framework setting out about ten principles theoretically makes it possible to achieve this objective.We are therefore studying the implementation of biodiversity offset through three High Speed Railway projects. We analyze the actor's game around this implementation through the theories of collective action, and in particular the analytical framework of Translation proposed by M. Callon. This first analysis allows us to understand how biodiversity offset is a socio-technical object. We highlight that many actors with diverging stakes are mobilizing to implement ecological compensation. We show that there is a tension between the mobilization of actors and ecological requirements, these two aspects are not always compatible. The duration of the environmental services specifications and the associated retribution of landowners, who set-up biodiversity offset specification, is decisive for both human and non-human (biodiversity) mobilization. We then question the temporal spatial effects of collective action and its ability to achieve a net loss of biodiversity. We show that the measures could not be effective before the impacts began. Land management in France seems for the moment to be difficult to reconcile with the implementation of unanticipated biodiversity offset at a very early stage. We show that the majority of biodiversity offset sites are small in size, although larger areas seem more virtuous for biodiversity. Finally, we show that the sustainability of biodiversity offset measures can be assessed at different levels depending on (i) the type of land control (acquisition, agreement); (ii) biodiversity offset contracts (duration, content of the latter - sanctions in the event of failure to comply with obligations influence the maintenance of the measures); (iii) the management of the renewal of these contracts; (iv) the vocation of the owners of the sites (a public or private construction company does not initially have the role of conserving biodiversity, whereas an environmental NGO has the vocation); (v) the sustainability of the structures and assurances as to the future of the biodiversity offset measures sites in the event of bankruptcy; (vi) the monitoring and control of the implementation
8
Chapon-Le, Brethon Aurélie. "Le principe d'égalité entre créanciers." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMR088.
Повний текст джерелаАнотація:
Depuis l'Antiquité, le principe d'égalité entre créanciers apparaît comme le principe fondateur des procédures collectives. Il permet de répartir de manière juste les actifs d'un débiteur impécunieux. Pourtant, l'existence et la portée de la norme sont sans cesse contestées. Les multiples réformes de la matière et ses nouvelles orientations économiques, la place grandissante du droit des sûretés, ainsi que l'internationalisation des procédures, ont contribué a renforcer les controverses autour du traitement égalitaire des créanciers. Les débats relatifs aux manifestations de l'égalité en droit de l'insolvabilité révèlent toutefois une problématique plus profonde liée a l'insuffisante définition de ce que constitue le principe d'égalité en procédure collective. Or, la notion d'égalité est ambivalente, il ne peut dès lors exister une unique signification du principe. Par ailleurs, l'égalité entre créanciers n'est pas qu'une simple règle mais constitue un véritable principe général du droit. Son caractère éminemment supérieur impose qu'il soit observé dans les différentes étapes de la procédure collective. Malgré les modifications législatives successives, il est possible de constater que le principe d'égalité entre créanciers constitue toujours la pierre angulaire du droit de l'insolvabilité. Les éléments traditionnels de la discipline collective demeurent et s'appliquent aujourd'hui sans distinction à tous les créanciers. Bien que l'élaboration de traitements différenciés soit de plus en plus récurrente, elle n'entraîne pas systématiquement une rupture d'égalité injustifiée. La rupture d'égalité formelle est admise des lors que les régimes différents mènent à la réalisation des objectifs des procédures ou visent à la protection d'intérêts supérieurs. Mais les vives critiques quant à la réalité du principe et les contestations portant sur ses manifestations ne sont pas toutes infondées. Le législateur à organisé un certain nombre de traitements privilégiés illégitimes, afin de satisfaire les intérêts personnels de quelques créanciers. Or, le respect du principe d'égalité est primordial en procédure collective pour repartir le poids de la dette du débiteur et renforcer l'impératif de moralisation du droit des affairesSince ancient times, equality between creditors appears to be the core principle of insolvency proceedings. It allows for a fairly sharing of the debtor's assets. However, existence and scope of that application standard are persistently contested. Many reforms, new economic orientations of the subject, added to the increasing place that securities law takes and the globalization of procedures have contributed to strengthen the debate around creditor's rights. Discussions about equality in the insolvency law though disclose a specific problem, due to an inadequate definition of equality principle in insolvency proceedings. More than anything, the concept of equality is ambivalent ; therefore, a single meaning for the principle is unmanageable. Furthermore, equality between creditors is not a plain rule but represents a full-fledged principle of law. That higher nature requires to be enforced at each stage of proceedings. In spite of subsequent amendments, the principle of equality between creditors appears to be the cornerstone of insolvency law. Traditional elements of the collective discipline remain and apply equality to all creditors. Development for differentiated treatments do not systematically lead to an unwarranted breach of equality. The breach of formal equality is accepted if the schemes carry out the proceedings objectives, or aim for protection of the best interests. Strong critics concerning the principle, and challenges about the expression are not unfounded for most. The legislator staged a number of unjust privileged treatments, with the aim of satisfying the personal interest of a few creditors. However, compliance with equality is essential in bankruptcy law for the purposes of sharing the assets and liabilities of the debt, and strengthen the imperative of moralization in business law
9
Vaissière, Anne-Charlotte. "Le recours au principe de compensation écologique dans les politiques publiques en faveur de la biodiversité : enjeux organisationnels et institutionnels : cas des écosystèmes aquatiques marins et continentaux." Thesis, Brest, 2014. http://www.theses.fr/2014BRES0028/document.
Повний текст джерелаАнотація:
La compensation écologique, envisagée dans le respect de la séquence éviter-réduire-compenser les impacts, cherche à apporter des réponses à la crise actuelle d’érosion de la biodiversité. L’objectif de la thèse est de comprendre quels sont les enjeux organisationnels et institutionnels de la mise en œuvre du principe de compensation écologique pour les impacts sur les écosystèmes aquatiques marins et continentaux en Europe et aux Etats-Unis. La thèse mobilise le cadre théorique de l’économie néo-institutionnelle. Les organisations de type hiérarchique (compensation au cas par cas) ont pour principales limites d’avoir une efficacité écologique discutable et de ne pas permettre le suivi et le contrôle des mesures compensatoires ce qui conduit souvent à ce que la compensation ne soit pas ou peu mise en œuvre. Aux Etats-Unis, les banques de compensation consistent en une réponse anticipée et mutualisée aux dommages à l’environnement. Il s’agit d’une forme organisationnelle alternative hybride fortement régulée à mi-chemin entre la hiérarchie et le marché. Cependant, les acteurs ont des stratégies collectives et individuelles qui engendrent des négociations ayant des conséquences sur les enjeux de développement économique et de maintien des objectifs de conservation de la biodiversité. Le système des banques de compensation crée un double phénomène de redistribution des coûts de transaction et de diminution de ceux-ci mais il semble que l’évolution de l’ensemble du cadre d’application de la compensation écologique américain permet aujourd’hui une complémentarité institutionnelle entre ces deux formes organisationnelles plutôt qu’une disparition des formes hiérarchiquesBiodiversity offset, as the last step of the mitigation hierarchy (avoid/reduce/offset), aims to address the current biodiversity loss crisis. The main goal of this PhD, which relies on the new institutional economics approach as a theoretical framework, is to understand the organizational and institutional issues of implementing biodiversity offsets policies for impacts on continental and offshore wetlands in Europe and the United-States. Hierarchical organizations (i.e. permittee responsible mitigation) often lead to little to no implementation of biodiversity offsets because the ecological effectiveness of case-by-case compensatory measures is unproven and the monitoring and control of numerous measures are difficult. In the United-States, the mitigation banking system aims to compensate for multiple small impacts on wetlands by carrying out restoration projects on fewer but larger wetland areas in order to reach the goal of no net loss of biodiversity. This hybrid organizational form is highly regulated and therefore stands halfway between hierarchical and market organizations. However, actors have individual and collective strategies that generate negotiations with consequences on economic development and biodiversity conservation stakes. The mitigation banking system leads to a decrease of transaction costs and a change of the actors bearing them. It seems that the evolution of the whole framework of biodiversity offsets policy implementation in the United-States leans toward an institutional complementarity between these two organizational forms rather than a disappearance of hierarchical organizations
10
Ginhoux, Romuald. "Compensation des mouvements physiologiques en chirurgie robotisée par commande prédictive." Phd thesis, Université Louis Pasteur - Strasbourg I, 2003. http://tel.archives-ouvertes.fr/tel-00004633.
Повний текст джерелаАнотація:
Il existe aujourd'hui de nombreux systèmes robotiques commerciaux pour l'assistance au geste chirurgical. Les interventions d'orthopédie, de neurologie, de chirurgie laparoscopique ou cardiaque peuvent désormais être assistées par des systèmes mécaniques et informatiques. Depuis les premiers robots d'aide au geste chirurgical dérivés des robots industriels, aux robots actuels, l'objectif est de développer des systèmes d'aide aux gestes médicaux et chirurgicaux qui apportent des bénéfices importants au chirurgien et au patient. Dans ce contexte, ce travail de thèse s'intéresse plus particulièrement à l'aide au geste chirurgical en chirurgie mini-invasive robotisée. La problématique abordée est de permettre à un robot chirurgical de compenser mécaniquement les mouvements physiologiques de l'organe ou du tissu opéré, afin de proposer au chirurgien une zone de travail virtuellement immobile. En effet, ces mouvements sont des perturbations pour le chirurgien qui télé-manipule un robot, car il doit les compenser lui-même à chaque fois qu'une tâche précise est requise à la surface d'un organe ou d'un tissu, en les accompagnant manuellement quand c'est possible. Ceci limite aujourd'hui le développement, entre autres, des opérations à coeur battant. L'objectif est de proposer un système de commande qui permette au robot de se déplacer de façon synchronisée avec l'organe et d'accompagner ainsi son mouvement. Ce travail se restreint aux mouvements physiologiques dus à la respiration et aux battements du coeur. Ceux-ci sont périodiques avec une période qui ne varie pas pendant l'intervention. Le principe utilisé pour commander le déplacement du robot est celui de l'asservissement visuel direct rapide, où les images d'une caméra d'observation endoscopique sont traitées en temps réel, avec une cadence d'asservissement jusqu'à 500 images par seconde. Le robot est commandé à l'aide de lois de commande prédictives dans lesquelles des modèles internes simples du robot et des mouvements à filtrer sont inclus. Les développements présentés dans cette thèse sont illustrés par deux ensembles de résultats, pour la compensation des mouvements respiratoires du foie d'une part, et le suivi du coeur battant d'autre part. Des dispositifs expérimentaux ont été mis en place autour d'un robot médical Aesop (Computer Motion, USA) et un prototype de robot chirurgical de la société Sinters de Toulouse. Des expériences de laboratoire et des tests in vivo en conditions chirurgicales réelles ont été réalisés.
Частини книг з теми "Principe de compensation des perturbations"
1
FAKHRI, S., D. PELISSON, and D. GUITTON. "Compensation for Perturbations of Gaze and Role of Vestibular Signals in Gaze Control." In Information Processing Underlying Gaze Control, 53–63. Elsevier, 1994. http://dx.doi.org/10.1016/b978-0-08-042506-1.50010-2.
Повний текст джерелаТези доповідей конференцій з теми "Principe de compensation des perturbations"
1
Neufeld, Chris, David Purcell, and Pascal Van Lieshout. "Articulatory compensation to second formant perturbations." In ICA 2013 Montreal. ASA, 2013. http://dx.doi.org/10.1121/1.4800692.
Повний текст джерела
2
Ama, S. T., Y. Okado, Y. Maeda, M. Iwasaki, and H. Hirai. "Adaptive deadbeat feedforward compensation for robust positioning performance against plant perturbations." In 2013 IEEE International Conference on Mechatronics (ICM). IEEE, 2013. http://dx.doi.org/10.1109/icmech.2013.6519122.
Повний текст джерела
3
De Veuster, Christophe, Artashes Yavrian, Yvon L. M. Renotte, Yves F. Lion, Tigran V. Galstian, and Roger A. Lessard. "Compensation of object beam perturbations in interferometric measurements with a phase conjugation mirror." In Lasers and Materials in Industry and Opto-Contact Workshop, edited by Michel Piche. SPIE, 1998. http://dx.doi.org/10.1117/12.326648.
Повний текст джерела
4
Janschek, Klaus, Valerij Tchernykh, Serguei Dyblenko, Gregory Flandin, and Bernd Harnisch. "Compensation of focal plane image motion perturbations with optical correlator in feedback loop." In Remote Sensing, edited by Roland Meynart, Steven P. Neeck, and Haruhisa Shimoda. SPIE, 2004. http://dx.doi.org/10.1117/12.565341.
Повний текст джерела
5
Horvath, Roland, George T. Flowers, and Jerry Fausz. "Passive Balancing for Rotor Systems Using Pendulum Balancers." In ASME 2005 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/detc2005-84194.
Повний текст джерелаАнотація:
An analytical, numerical and experimental investigation of the dynamic behavior of a passive balancing system is presented. Due to the system constraints and dynamic characteristics, this system is capable of combined static and dynamic mass balancing. This work is an extension of previous studies in which ball-balancing systems were used to reduce harmful vibration caused by radial perturbation in the principal axis of inertia. In the present research, the imbalance compensation problem is divided into axial and radial components. A spherical suspension was applied at the rotational axis that allows the rotating disk to tilt, thus eliminating coupled dynamic centrifugal forces caused by the axial mass imbalance. In a fashion similar to earlier ball balancing systems, in this study the balancing balls were replaced by two single pendulums suspended in the geometrical axis of a disk in order to compensate for radial unbalance. The governing equations are developed, which results in a set of cross-coupled nonlinear differential equations, which are analyzed in detail. An experimental study is also conducted to validate and test the conclusions of the analysis and simulation work.
6
Kuczenski, Brandon, William C. Messner, and Philip R. LeDuc. "Controlled Waveform Chemical Stimulus of Cellular Subdomains for System Identification." In ASME 2008 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2008. http://dx.doi.org/10.1115/sbc2008-193053.
Повний текст джерелаАнотація:
The dynamic behavior of cells is a subject of extensive investigation. Current attempts to model and describe cell behavior show similarity to traditional engineering models of dynamic systems, often making use of the same vocabulary and principles (e.g. amplification, feedback, regulation, instability). A significant difference between biological dynamic systems and engineered ones is that the latter often feature a designed compensator whose dynamic behavior modulates the dynamic response of the system through closed-loop feedback control. In biological systems, by contrast, the feedback is often implicit, and the investigator has no direct control over modulations which are internal to the system. Although disruptive techniques like synthetic siRNA [1] or genetic modification can certainly change cellular behavior, in some cases it is desirable to probe the dynamics of cellular processes without changing their essential operation, or without substantial delay between applying a perturbation and observing its effects.
7
Moura, Jairo, and Martin Hosek. "Neural Network Based Perturbation Identification Approach for High Accuracy Tracking Control of Robotic Manipulators." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-41179.
Повний текст джерелаАнотація:
This paper proposes an approach for high accuracy tracking control of a robotic manipulator in the presence of model perturbations. The proposed approach designs a neural network for estimation and compensation of the modeling errors, also referred to as perturbations. Experiments are carried out on a five-axis direct-drive robotic manipulator for automated pick-place operations in semiconductor manufacturing applications. It is shown that the proposed approach can substantially improve the robot tracking and settling performance of the original computed torque algorithm implemented.
8
Gysling, D. L., and E. M. Greitzer. "Dynamic Control of Rotating Stall in Axial Flow Compressors Using Aeromechanical Feedback." In ASME 1994 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1994. http://dx.doi.org/10.1115/94-gt-292.
Повний текст джерелаАнотація:
Dynamic control of rotating stall in an axial flow compressor has been implemented using aeromechanical feedback. The control strategy developed used an array of wall jets, upstream of a single-stage compressor, which were regulated by locally reacting reed valves. These reed valves responded to flowfield pressure perturbations associated with the small amplitude perturbations that precede rotating stall. The valve design was such that the combined system, compressor plus reed valve controller, was stable under operating conditions that had been unstable without feedback. A 10% decrease in the stalling flow coefficient was achieved using the control strategy, and the stable flow range was extended with no noticeable change in the steady state performance of the compression system. The experimental demonstration is the first use of aeromechanical feedback to extend the stable operating range of an axial flow compressor. It is also the first use of local feedback and dynamic compensation techniques to suppress rotating stall. The design of the experiment was based on a two-dimensional stall inception model which incorporated the effect of the aeromechanical feedback. The physical mechanism for rotating stall in axial flow compressors was examined with focus on the role of dynamic feedback in stabilizing compression system instability. The effectiveness of the aeromechanical control strategy was predicted, and experimentally demonstrated, to depend on a set of non-dimensional control parameters that determine the interaction of the control strategy and the rotating stall dynamics.