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Auswahl der wissenschaftlichen Literatur zum Thema „Periodická regulace“
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Zeitschriftenartikel zum Thema "Periodická regulace"
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Burov, A. A., I. I. Kosenko und V. I. Nikonov. „Spacecraft with Periodic Mass Redistribution: Regular and Chaotic Behaviour“. Nelineinaya Dinamika 18, Nr. 4 (2022): 639–49. http://dx.doi.org/10.20537/nd221222.
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The motion of a spacecraft containing a moving massive point in the central field of Newtonian attraction is considered. Within the framework of the so-called “satellite approximation”, the center of mass of the system is assumed to move in an unperturbed elliptical Keplerian orbit. The spacecraft’s dynamics about its center of mass is studied. Conditions under which the spacecraft rotates about a perpendicular to the plane of the orbit uniformly with respect to the true anomaly are found. Such uniform rotations are achieved using a specially selected rule for changing the position of a massive point with respect to the spacecraft. Necessary conditions for these uniform rotations are studied numerically. An analysis of the nonintegrability of a special class of spacecraft’s rotation is carried out using the method of separatrix splitting. Poincaré sections are constructed for certain parameter values. Several linearly stable periodic motions are pointed out and investigated.
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Sukhov, E. A. „Bifurcation Analysis of Periodic Motions Originating from Regular Precessions of a Dynamically Symmetric Satellite“. Nelineinaya Dinamika 15, Nr. 4 (2019): 593–609. http://dx.doi.org/10.20537/nd190419.
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3
Ming Chen, Ming Chen, Xiangdong Liu Xiangdong Liu, Yuehua Liu Yuehua Liu und Mingwen Zhao Mingwen Zhao. „Characterization of regular periodic surface structure by multi-pulse laser irradiation of a Zinc target“. Chinese Optics Letters 10, Nr. 5 (2012): 051402–51404. http://dx.doi.org/10.3788/col201210.051402.
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4
Wang, W. M., K. P. Rajurkar und K. Akamatsu. „Digital Gap Monitor and Adaptive Integral Control for Auto-Jumping in EDM“. Journal of Engineering for Industry 117, Nr. 2 (01.05.1995): 253–58. http://dx.doi.org/10.1115/1.2803302.
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This paper reports a monitoring and adaptive integral control strategy for EDM to regulate the cycle time of the periodical retraction (jumping) of the tool electrode according to the gap condition. A digital EDM gap monitor has been developed to detect the time ratios of gap states with a resolution of 0.2 μs. The theoretical and experimental analysis of the effect of sensing parameter combinations on control aspects and performance of manual setting, integral control and adaptive integral control methods have been carried out. Experimental verification shows that the proposed system results in higher erosion rate, better machining stability, and complete avoidance of arc damage.
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Švitra, Donatas, und Renata Retkutė. „Dinamic of blood pluripotential stem cell formation processes“. Lietuvos matematikos rinkinys, Nr. II (14.12.1998): 326–33. https://doi.org/10.15388/lmd.1998.37926.
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It has been suspected that periodical haematological deases arise because of abnormalities in the feedback mechanism that regulate blood cell number. It is generally believed that there exist the self maintaiting pluripotential stem cell population (PPSC) capable of producing committed stem cells specialised for the erithroid, myleoid or thromboid cell lines. The production of PPSC is regulated by two types of feedback mechanisms: (1) long range humoral mechanisms; (2) local environmental mechanisms. The property of these feedback mechanisms is the presence of time delays which arise, for example, because of finite cell maturation time. With the help of difference-differential equations the processes of the PPSC production are modeled. The models, which use logistic and Mono lows are linear analised and simulated by computer.
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Bao, Yan Gang, und Xiao Dong Wang. „A Computational Model for Nanoscale Self-Assembly of Monolayer Surfaces“. Solid State Phenomena 121-123 (März 2007): 1033–36. http://dx.doi.org/10.4028/www.scientific.net/ssp.121-123.1033.
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A computational model is proposed to analyze the nanoscale self-assembling phenomenon of monolayers on heterogeneous surfaces. Morse potential is used to describe the pairpotential between molecules or atoms. Minimization of free energy is used to regulate different phases and lattices to form optimized heterogeneous structures of different sizes with periodical patterns. A representative volume element (RVE) is first defined and an optimization algorithm is developed to adjust the positions of particles in it to reduce its potential until global equilibrium is reached. The pair-potential distribution in the monolayer and the substrate layers are studied. It is interesting to observe that the pair-potential distribution in the substrate layers resumes uniformity just a few layers away from the interfacial boundary.
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Ma, Yuchuan, Qiao Wang, Min Ye und Gaoqi Lian. „Robust Control for the Hybrid Energy System of an Electric Loader“. Machines 11, Nr. 4 (04.04.2023): 454. http://dx.doi.org/10.3390/machines11040454.
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With the wide application of electric vehicles and the development of battery technology, pure electric construction machinery (PECM) has received more and more attention due to its high efficiency and no pollution. The working conditions of construction machinery are complex and accompanied by periodical working conditions and heavy load. For electric construction machinery, a heavy load represents an energy supply with a large current. To adapt to the working conditions of PECM, this paper proposes a robust controller to regulate the current of the hybrid energy system (HES) which include the battery and supercapacitor. The V-type operating conditions of a 5-ton pure electric loader are the research focus to analyze the working principles of the HES. The topology and energy flow patterns of the HES are proposed and analyzed. The model of the battery, supercapacitor, and DC/DC converter are depicted, and the robust control method is designed. An electric loader experiment platform is created to verify the effectiveness of the robust control method. Compared with the proportional integral control effect, the experiment results show that the proposed control method had good control performance and could better regulate the current. It can be used as a reference value for other dual energy source PECM.
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Yakymiv, Y. V., und O. M. Bortnyak. „ENERGY EFFICIENCY OF OPERATING MODES OF MAIN OIL PIPELINES WITH PERIODICAL PARTIAL OIL DUMPING“. PRECARPATHIAN BULLETIN OF THE SHEVCHENKO SCIENTIFIC SOCIETY Number, Nr. 2(46) (14.12.2018): 151–60. http://dx.doi.org/10.31471/2304-7399-2018-2(46)-151-160.
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Modern oil transportation systems are characterized by a complex hydraulic structure and geometric configuration, and often require the need for a permanent or periodic pumping or dumping part of the oil flow. The implementation of such transportation technology necessarily leads to changes in the operating conditions of oil pipelines and in accordance with the need to regulate the operation of oil pumping stations. Consequently, determining the patterns of the impact of the process of dumping the part of the oil on the energy parameters of the operation of oil transportation systems is an extremely important task.The influence of periodic dumping the part of oil on the energy efficiency of the operation of main oil pipelines was studied. The impact of volume of discharges on the consumption of power on pumping oil in the system of the main oil pipeline was analyzed. It has been found that with the increase the volume of discharges, the specific consumption of electricity for oil pumping decreases.Based on the carried research, the recommendations on the selection of reliable, safe and optimal pumping modes in terms of cost of electricity for the operation of oil pipelines "Druzhba" in the direction of Mozyr - Brody - Tukholsky pass with periodical partial oil dumping on LPDS "Brody".
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MohanraoGarud, Aakanksha, und V. G. Bhamre. „A REVIEW PAPER ON STRUCTURAL DAMAGE IDENTIFICATION OF CANTILEVER BEAM BY USING VIBRATION TECHNIQUE, FINITE ELEMENT ANALYSIS & ARTIFICIAL NEURAL NETWORK“. International Journal of Research -GRANTHAALAYAH 3, Nr. 12 (31.12.2015): 125–28. http://dx.doi.org/10.29121/granthaalayah.v3.i12.2015.2896.
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In this review paper structural damage identification work in cantilever beam is done by using the Artificial Neural Network as diagnostic parameter. The study is based on the concept that natural frequency is inversely proportional to the mass of the structure. Thus to regulate the proper condition of structure, periodical frequency measurement is necessary. But in dynamic conditions and in complicated structures frequency measurement is difficult, for the same we reviewed various papers to identify the structural damage using various methods. The factors which affects on the damage of structural parts like crack depth, crack location etc. is also discussed in this work. Natural frequency is measured with the help of fast fourier transform by various authors and artificial neural network is also used for identification of the damage in many papers. So in this review work we studied methods of structural damage identification such as vibrations, finite element analysis and artificial neural network.
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Jafroudi, Maryam. „Climate change and accommodation of water availability in transboundary rivers: lessons learned from the Guadiana basin“. Water Policy 20, Nr. 2 (05.01.2018): 203–17. http://dx.doi.org/10.2166/wp.2018.178.
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Abstract Historically, states have found it useful to regulate their relationship over their shared water resources via treaties. While treaties provide some element of predictability and certainty with regard to the future supplies of water to the riparian states, they also need to incorporate mechanisms that allow flexibility to respond to changes in the quantity of water available for allocation amongst the parties. This requirement is especially relevant when global climate change is causing freshwater resources to shrink. The legal regime of the Guadiana, as an example of a modern legal regime of a transboundary river, includes some provisions that permit the riparian states to accommodate the variability of the Guadiana's streamflow in response to climate change within the water allocation arrangements. The lessons learned from these provisions, which include periodical update of the historical mean precipitation values, updating the flow regime of the rivers and cancelling minimum flow requirements under special circumstances, may contribute to climate-proofing international transboundary agreements within the catchments where climate-change induced water scarcity poses a major threat.
Dissertationen zum Thema "Periodická regulace"
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Yuksel, Can Kutlu. „Simultaneous Time-Delay Compensation and Periodic Control“. Electronic Thesis or Diss., université Paris-Saclay, 2025. http://www.theses.fr/2025UPAST024.
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Il existe différents scénarios dans lesquels on exige qu'un système fonctionne de manière périodique et, par conséquent, un besoin durable d'avoir un contrôleur capable de répondre à cette demande. On peut dire que l'approche la plus courante pour construire ces contrôleurs est le paradigme de conception du contrôle répétitif. Néanmoins, si les systèmes considérés souffrent de retards temporels et/ou de types particuliers de signaux périodiques, les directives du paradigme du contrôle répétitif peuvent être trop strictes et tirées par les cheveux pour être suivies. La thèse cherche des moyens alternatifs de construire le contrôleur dans le cadre du contrôle par modèle interne et étudie les structures ressemblant à celles du contrôle répétitif mais avec des variables libres différentes pour transférer de manière pratique les idées principales du contrôle périodique aux systèmes à retard temporel. La structure de contrôleur IMC proposée consiste en un inverse sans retard du modèle approximant le système, des filtres passe-bas pour assurer la pertinence du contrôleur et des retards temporels pour façonner la réponse en fréquence de la boucle fermée globale. La première proposition de conception utilise des filtres de troisième ordre et des retards groupés pour réaliser la régulation périodique de systèmes approximés par des modèles de premier ordre avec retard temporel. La motivation derrière cela est de répondre à la demande de flexibilité et de commodité dans les applications industrielles. La deuxième approche de conception considère un filtre construit sur la base des zéros et des pôles souhaités pour la sensibilité en boucle fermée. Un avantage notable de cette approche, contrairement à la première, est que les systèmes d'ordre élevé avec des retards peuvent en outre être traités analytiquement. La dernière conception considère un retard distribué ressemblant étroitement aux structures utilisées pour les contrôleurs répétitifs d'ordre élevé. Néanmoins, une différence notable est que les composants de retard groupés dans le retard distribué ne sont pas nécessairement liés à la période du signal ciblé. L'utilisation du retard fait varier le contrôleur de manière linéaire par rapport à ses paramètres, ce qui, par conséquent, favorise une approche de conception basée sur l'optimisation. Enfin, une théorie préliminaire basée sur la paramétrisation de Youla-Kucera est présentée comme une orientation future pour la recherche. Cette théorie révèle que les contrôleurs répétitifs et les contrôleurs basés sur IMC peuvent être considérés comme une réalisation particulière de la paramétrisation. De plus, ce paramètre montre que les méthodes de conception proposées pour le contrôle périodique peuvent être étendues aux systèmes instables à retard infini de dimensionThere are various scenarios where one demands a system to operate in a periodic manner and, therefore, a lasting need to have a controller that can meet this demand. Arguably, the most common approach to construct these controllers is the Repetitive Control design paradigm. Nevertheless, if the considered systems suffer from time-delays and/or particular types of periodic signals, then the guidelines from the repetitive control paradigm may be too strict and far-fetched to follow. The thesis seeks alternative ways of constructing the controller in the Internal Model Control framework and studies the structures resembling that of the repetitive control but with different free-variables to conveniently carry over the main ideas for periodic control to time-delay systems. The proposed IMC controller structure consists of a delay-free inverse of the model approximating the system, low-pass filters to ensure the properness of the controller, and time-delays to shape the frequency response of the overall closed-loop. The first design proposition utilizes third-order filters and lumped delays to achieve the periodic regulation of systems approximated by first-order models with time-delay. The motivation behind this is to meet the demand for flexibility and convenience in industrial applications. The second design approach considers a filter constructed based on the zeros and poles desired for the closed-loop sensitivity. A notable advantage of this approach, in contrast to the first one, is that high-order systems with delays can be additionally addressed analytically. The last design considers a distributed delay closely resembling the structures used for high-order repetitive controllers. Nevertheless, a notable difference is that the lumped delay components within the distributed delay are not necessarily related to the period of the targeted signal. The use of the distributed delay makes the controller vary linearly with respect to its parameters, which, as a consequence, favors an optimization-based design approach. Finally, a preliminary theory based on Youla-Kucera parametrization is presented as a future direction for the research. This theory reveals that repetitive controllers and IMC-based controllers can be viewed as a particular realization of the Youla-Kucera parametrization. Moreover, this parameter shows that the proposed design methods for periodic control can be extended to unstable infinite-dimensional time-delay systems
Existují různé scénáře, kdy je vyžadováno, aby systém fungoval periodickým způsobem, a proto existuje trvalá potřeba mít regulátor, který tuto poptávku dokáže splnit. Pravděpodobně nejběžnějším přístupem ke konstrukci těchto regulátorů je návrhové paradigma opakovaného řízení. Pokud však uvažované systémy trpí časovými zpožděními a/nebo určitými typy periodických signálů, pak mohou být pokyny z paradigmatu opakovaného řízení příliš přísné a přitažené za vlasy, než aby se daly dodržovat. Práce hledá alternativní způsoby konstrukce regulátoru v rámci Internal Model Control a studuje struktury podobné repetitivnímu řízení, ale s různými volnými proměnnými, aby bylo možné pohodlně přenést hlavní myšlenky periodického řízení do systémů s časovým zpožděním. Navrhovaná struktura IMC regulátoru sestává z bezprodlevové inverze k modelu aproximujícího systém, dolních propustí pro zajištění správnosti regulátoru a časových zpoždění pro tvarování frekvenční odezvy celkové uzavřené smyčky. První návrh návrhu využívá filtry třetího řádu a koncentrovaná zpoždění pro dosažení periodické regulace systémů aproximované modely prvního řádu s časovým zpožděním. Motivací je splnit požadavky na flexibilitu a pohodlí v průmyslových aplikacích. Druhý návrhový přístup uvažuje filtr konstruovaný na základě nul a pólů požadovaných pro citlivost v uzavřené smyčce. Významnou výhodou tohoto přístupu, na rozdíl od prvního, je to, že systémy vyššího řádu se zpožděním lze dodatečně řešit analyticky. Poslední návrh uvažuje s distribuovaným zpožděním, které se velmi podobá strukturám používaným pro opakující se regulátory vysokého řádu. Nicméně významný rozdíl je v tom, že koncentrované složky zpoždění v rámci distribuovaného zpoždění nemusí nutně souviset s periodou cíleného signálu. Použití zpoždění způsobí, že regulátor se lineárně rozloží s ohledem na jeho parametry, což v důsledku upřednostňuje přístup návrhu založený na optimalizaci. Nakonec je představena předběžná teorie založená na parametrizaci Youla-Kucera jako budoucí směr výzkumu. Tato teorie odhaluje, že na repetitivní regulátory a regulátory založené na IMC lze pohlížet jako na konkrétní realizaci parametrizace Youla-Kucera. Tento parametr navíc ukazuje, že navrhované metody návrhu pro periodické řízení lze rozšířit na nestabilní systémy s nekonečně velkým časovým zpožděním
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Li, Chen. „Ultrafast laser-induced nanostructuring of metals in regular patterns“. Thesis, Lyon, 2016. http://www.theses.fr/2016LYSES019/document.
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Les structures périodiques de surface induites par laser femtoseconde(fs-LIPSS) attirent l'attention scientifique et technique en raison de la possibilité de produire des nanostructures en dessous de la longueur d'onde optique. Ces éléments sont essentiels pour l'ingénierie de surface et les procédés, notamment en tribologie, mouillabilité, la mécanique, le marquage et la lutte contre la contrefaçon. Selon le régime d'interaction laser, en particulier la fluence du laser, le nombre d'impulsions et le type de matériaux, les impulsions ultracourtes peuvent induire des basses et des hautes fréquences spatiales-LIPSS (LSFL et HSFL), avec l'orientation perpendiculaire (┴E) ou parallèle (║E) à la polarisation du laser. Compte tenu de leur potentiel pour la nano-fabrication, ce travail se concentre sur les mécanismes potentiels de formation des LIPSS, en particulier la formation des HSFL sur les alliages métalliques. Afin d'étudier les indices optiques transitoires de matériaux excités dans la formation fs-LIPSS, nous avons d'abord développé de l’ellipsométrie résolue en temps afin de mesurer les indices optiques dynamiques des matériaux excités. Ainsi, nous avons obtenu un aperçu de la dynamique de la fonction diélectrique intrinsèquement liée à la configuration électronique et au réseau cristallin. Des simulations de premiers principes sont ensuite utilisées pour révéler la façon dont la configuration électronique change au cours de l'excitation, responsable d’indices optiques transitoires. Les effets des indices optiques transitoires sont pris en compte dans les mécanismes de formation de LIPSS. Sur la base d’expériences de formations des fs-LIPSS sur six matériaux différents, incluant du tungstène métallique, du silicium semiconducteur, de la silice fondue diélectrique, un superalliage monocristallin CMSX-4, un alliage amorphe de Zr-BMG et son alliage cristallin correspondant Zr-CA, nous étudions les mécanismes de formation des LIPSS dans le domaine électromagnétique par des simulations de différences finies dans le domaine temporel (FDTD), liées à la distribution d'énergie électromagnétique suivie par la dynamique de l'excitation optique et par l'évolution de la topologie avec le nombre d’impulsions et les matériaux. Nous nous concentrons sur l'origine électromagnétique de la formation des LIPSS et révélons un facteur principal potentiel de leur formation. Elle peut être expliquée par la modulation de l'énergie déposée sur la surface par des effets électromagnétiques. La modulation de l'énergie provient principalement de l'interférence entre le laser incident et les ondes de surface diffusées (pour LSFL ( ┴ E)), complétée par l'interférence entre les ondes de surface diffusées (pour HSFL (┴E)). Spécialement, pour HSFL (║E) sur Zr-CA, nous avons proposé que les scénarios de formation reposent sur des processus individuels d’exaltation anisotrope du champ. La topologie de surface, évoluant avec le nombre d'impulsions laser, induit une modulation d'énergie déposée sur la surface définie et amplifiée par la rétroactionFemtosecond laser-induced periodic surface structures (fs-LIPSS) attract the scientific and technical attention due to the ability to produce nanostructures below the optical wavelength. These are essential for surface engineering and treatment, notably in tribology, wettability, mechanics, marking and counterfeiting. Depending on the regime of laser interaction, particularly on the laser fluence, pulse number and material type, ultrashort pulses can induce the low- and high-spatial-frequency-LIPPS (LSFL and HSFL), with the orientation perpendicular (┴E) or parallel (║E) to the laser polarization. Considering their potential in the nano-manufacturing, this work focuses on potential mechanisms for LIPSS formation, especially HSFL formation on the metallic alloys. In order to investigate the transient optical indices of excited materials in fs-LIPSS formation, we first developed time-resolved ellipsometry to measure dynamic optical indices of excited materials. Thus we gain insights in the dynamics of the dielectric function where this is intrinsically related to the electronic configuration and lattice structure. First principle simulations are then used to reveal how the electronic configuration changes during the excitation, responsible for the transient optical indices. The effects of transient optical indices are considered in the LIPSS formation mechanisms. Based on the experiments of fs-LIPSS formations on six different materials, involving metal tungsten, semiconductor silicon, dielectric fused silica, single-crystal superalloy CMSX-4, amorphous alloy Zr-BMG and its corresponding crystal alloy Zr-CA, we investigate the LIPSS formation mechanisms in the electromagnetic domain by finite-difference time-domain (FDTD) simulations, related to the electromagnetic energy distribution followed by the dynamics of optical excitation, evolving topologies with pulse number and materials.We focus on the electromagnetic origin of LIPSS formation and reveal a potential primary factor for LIPSS formation. LIPSS formation can be explained by deposited energy modulation on surface via electromagnetic effects. The energy modulation mainly comes from the interference between incident laser and scattered surface wave (for LSFL(┴E)), being complemented by the interference between scattered surface waves (for HSFL(┴E)). Specially, for HSFL (║E) on Zr-CA, we proposed that the formation scenarios rely on individual anisotropic field-enhancement processes. The evolving surface topology with laser pulse number leads to a feedback-driven energy modulation deposited on surface
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Yun-Jhen und 吳昀臻. „Factors associated with regular periodical papanicolaus smear screening in Keelung City women“. Thesis, 2009. http://ndltd.ncl.edu.tw/handle/53974148836046823610.
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碩士中山醫學大學
公共衛生學系碩士班
97
Objectives: The purpose of this study was to analysis the relationship between regular papanicolaus (pap) smear screening and the experience of the "Keelung Community-based Integrated Screening" (KCIS) in Keelung City women over 30 years. Methods: The data of this study were draw from 2000 to 2007 Keelung Community-based Integrated Screening (KCIS) and records of pap smear in the Bureau of Health Promotion. 90,382 records were included. The dependent variable was behavior of regular papanicolaus (pap) smear screening. The independents included social-demographic variables, family disease history, personal disease history, and health behaviors. The main statistic method was logistic regression, using SAS 9.1 version package. Results: Women who had experience of KCIS had higher rate of regular pap smear screening than who had not. In KCIS participants, women who were higher levels education and have a spouse, had family disease history, never smoking, and exercise behavior more likely to have regular pap smear screening. Conclusion: The study found that women who had experience of KCIS, highly educated, have a spouse, have a family disease history, have no individual history of chronic illness, never smoking and have exercise behavior were more likely to receive regular pap smear screening. Encourage women to participate KCIS may could effectively promote women to receive regularly pap smear screening in addition to health education and advocacy strategies.
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Liao, Ting-De, und 廖庭德. „Chaos and regular pulses generated by quasi-periodic states in dual-feedback semiconductor laser“. Thesis, 2018. http://ndltd.ncl.edu.tw/handle/d382ff.
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碩士元智大學
光電工程學系
106
In this thesis, nonlinear dynamics of single-mode distributed feedback (DFB) semiconductor laser subject to dual feedback composed of both optical feedback and optoelectronic feedback to investigate experiment. By carefully adjusting the operational conditions, such as optical and optoelectronic feedback strength, delay lengths of optical and optoelectronic feedback loops, various dynamical states are found. The dynamical states shown in individual system are observed in the hybrid schemes, including period-one (P1) oscillation, quasi-periodic (QP) oscillation and pulsation, regular pulsation (RP), chaotic oscillation (CO) and pulsation (CP). As increasing the optical feedback strength, a quasi-periodic route to chaos is observed while other parameters are fixed. Furthermore, potential applications in generation of broadband chaos and stabilized regular pulses generated from quasi-periodic states are studied. The QP state is firstly generated by pure OEF system and then applied an additional OF system to obtain the chaos and regular pulses by tuning the controllable conditions of optical feedback strength and delay time. To explore the microwave signals generated by quasi-periodic states in the dual feedback system, we also measure suppression ratio of unwanted frequency side peak, RF spectral linewidth, and the single-side band (SSB) phase noise in frequency domain. On the other hand, the corresponding time series are also considered and discussed by calculating the amplitude variation of regular pulses and pulse widths. Moreover, a side peak suppression ratio of about 53 dB is achieved when applying the hybrid feedback scheme. The amplitude variation of regular pulses of 0.00440 is observed and the pulse-width is approximately 0.12 ns which is smaller than those coefficient when applying individual OF and OEF system. The improved percentage of averaged amplitude variation in regular pulses of around 78.3 % is also obtained. Furthermore, the complexity of chaotic waveforms generated by hybrid feedback system are discussed and calculated.
Bücher zum Thema "Periodická regulace"
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Cooper, Stuart. Regulation - the movie: A semiotic study of the periodic review of UK regulated industry. Birmingham: Aston Business School, Aston University, 1998.
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Daly, Donna, und Christopher Chapple. Anatomy, neurophysiology, and pharmacological control mechanisms of the bladder. Herausgegeben von Christopher R. Chapple. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780199659579.003.0034.
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The lower urinary tract has two main functions; the collection and low pressure storage of urine and periodical controlled elimination of urine at an appropriate time. In order to achieve continence during bladder filling and storage and produce efficient and effective bladder emptying, there is accurate coordination between opening and closing of the urethral sphincters and contraction of the detrusor smooth muscle. The process of micturition has two phases: the storage/filling phase and the voiding phase. The analogy for the transition between these two phases has been described as an on-off circuit, rather akin to flicking a light switch, between synchronous bladder contraction and urethral outlet relaxation, and vice versa. These phases are regulated by a complex, integration of somatic and autonomic efferent and afferent mechanisms that coordinate the activity of the bladder and urethra. This chapter provides an overview of our current understanding of these complex mechanisms.
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Huffaker, Ray, Marco Bittelli und Rodolfo Rosa. Entropy and Surrogate Testing. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198782933.003.0005.
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Reconstructing real-world system dynamics from time series data on a single variable is challenging because real-world data often exhibit a highly volatile and irregular appearance potentially driven by several diverse factors. NLTS methods help eliminate less likely drivers of dynamic irregularity. We set a benchmark for regular behavior by investigating how linear systems of ODEs are restricted to exponential and periodic dynamics, and illustrating how irregular behavior can arise if regular linear dynamics are corrupted with noise or shift over time (i.e., nonstationarity). We investigate how data can be pre-processed to control for the noise and nonstationarity potentially camouflaging nonlinear deterministic drivers of observed complexity. We can apply signal-detection methods, such as Singular Spectrum Analysis (SSA), to separate signal from noise in the data, and test the signal for nonstationarity potentially corrected with SSA. SSA measures signal strength which provides a useful initial indicator of whether we should continue searching for endogenous nonlinear drivers of complexity. We begin diagnosing deterministic structure in an isolated signal by attempting to reconstructed a shadow attractor. Finally, we use the classic Lorenz equations to illustrate how a deterministic nonlinear system of ODEs with at least three equations can generate observed irregular dynamics endogenously without aid of exogenous shocks or nonstationary dynamics.
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Wang, Bin. Intraseasonal Modulation of the Indian Summer Monsoon. Oxford University Press, 2018. http://dx.doi.org/10.1093/acrefore/9780190228620.013.616.
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The strongest Indian summer monsoon (ISM) on the planet features prolonged clustered spells of wet and dry conditions often lasting for two to three weeks, known as active and break monsoons. The active and break monsoons are attributed to a quasi-periodic intraseasonal oscillation (ISO), which is an extremely important form of the ISM variability bridging weather and climate variation. The ISO over India is part of the ISO in global tropics. The latter is one of the most important meteorological phenomena discovered during the 20th century (Madden & Julian, 1971, 1972). The extreme dry and wet events are regulated by the boreal summer ISO (BSISO). The BSISO over Indian monsoon region consists of northward propagating 30–60 day and westward propagating 10–20 day modes. The “clustering” of synoptic activity was separately modulated by both the 30–60 day and 10–20 day BSISO modes in approximately equal amounts. The clustering is particularly strong when the enhancement effect from both modes acts in concert. The northward propagation of BSISO is primarily originated from the easterly vertical shear (increasing easterly winds with height) of the monsoon flows, which by interacting with the BSISO convective system can generate boundary layer convergence to the north of the convective system that promotes its northward movement. The BSISO-ocean interaction through wind-evaporation feedback and cloud-radiation feedback can also contribute to the northward propagation of BSISO from the equator. The 10–20 day oscillation is primarily produced by convectively coupled Rossby waves modified by the monsoon mean flows. Using coupled general circulation models (GCMs) for ISO prediction is an important advance in subseasonal forecasts. The major modes of ISO over Indian monsoon region are potentially predictable up to 40–45 days as estimated by multiple GCM ensemble hindcast experiments. The current dynamical models’ prediction skills for the large initial amplitude cases are approximately 20–25 days, but the prediction of developing BSISO disturbance is much more difficult than the prediction of the mature BSISO disturbances. This article provides a synthesis of our current knowledge on the observed spatial and temporal structure of the ISO over India and the important physical processes through which the BSISO regulates the ISM active-break cycles and severe weather events. Our present capability and shortcomings in simulating and predicting the monsoon ISO and outstanding issues are also discussed.
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Daudon, Michel, und Paul Jungers. Uric acid stones. Herausgegeben von Mark E. De Broe. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780199592548.003.0202_update_001.
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Uric acid (UA) stones are typically red-orange and often appear as sand/ gravel though they may be large. They are totally radiolucent. They account for about 10% of all kidney stones in most countries, and up to 20% in some populations. It is twice as frequent in males, prevalence increases with age, and it is two to three times higher in patients with type 2 diabetes or with features of the metabolic syndrome. Factors that induce the formation of UA stones are a low urine volume, hyperuricosuria, and, more importantly, a permanently low urine pH (< 5). Indeed, below its pKa of 5.35 at 37°C, UA is in non-dissociated form, whose solubility is at best 100 mg/L, whereas urinary UA excretion normally exceeds 600 mg/day and may exceed 1g/day.Because UA solubility increases up to approximately 500 mg/L at urine pH > 6, urine alkalinization, with a target pH of 6.5–7, is the cornerstone of medical treatment. This most often allows dissolution of existing stones and prevention of recurrent stone formation so that urological intervention is infrequently needed. The preferred agent for alkalinization is potassium citrate (30–60 mEq/day in divided doses), because potassium urate is twice more soluble than sodium urate. However, in patients with poor gastric tolerance to potassium citrate or contraindication to potassium supplements, sodium bicarbonate is an acceptable alternative. Limitation of animal proteins, purine-rich foods (including beer), alcoholic drinks and acidified beverages (sodas) are useful measures, together with large fluid intake (> 2–2.5 L/day). Allopurinol may be indicated in cases of symptomatic hyperuricaemia. Regular observance of alkalinisation, with periodic controls of urine pH by the patient, is needed to prevent the rapid formation of UA stones. Patients affected by UANL, especially if overweight, should be evaluated for type 2 diabetes or glucose intolerance and managed accordingly.
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Omstedt, Anders. The Development of Climate Science of the Baltic Sea Region. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190228620.013.654.
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Dramatic climate changes have occurred in the Baltic Sea region caused by changes in orbital movement in the earth–sun system and the melting of the Fennoscandian Ice Sheet. Added to these longer-term changes, changes have occurred at all timescales, caused mainly by variations in large-scale atmospheric pressure systems due to competition between the meandering midlatitude low-pressure systems and high-pressure systems. Here we follow the development of climate science of the Baltic Sea from when observations began in the 18th century to the early 21st century. The question of why the water level is sinking around the Baltic Sea coasts could not be answered until the ideas of postglacial uplift and the thermal history of the earth were better understood in the 19th century and periodic behavior in climate related time series attracted scientific interest. Herring and sardine fishing successes and failures have led to investigations of fishery and climate change and to the realization that fisheries themselves have strongly negative effects on the marine environment, calling for international assessment efforts. Scientists later introduced the concept of regime shifts when interpreting their data, attributing these to various causes. The increasing amount of anoxic deep water in the Baltic Sea and eutrophication have prompted debate about what is natural and what is anthropogenic, and the scientific outcome of these debates now forms the basis of international management efforts to reduce nutrient leakage from land. The observed increase in atmospheric CO2 and its effects on global warming have focused the climate debate on trends and generated a series of international and regional assessments and research programs that have greatly improved our understanding of climate and environmental changes, bolstering the efforts of earth system science, in which both climate and environmental factors are analyzed together.Major achievements of past centuries have included developing and organizing regular observation and monitoring programs. The free availability of data sets has supported the development of more accurate forcing functions for Baltic Sea models and made it possible to better understand and model the Baltic Sea–North Sea system, including the development of coupled land–sea–atmosphere models. Most indirect and direct observations of the climate find great variability and stochastic behavior, so conclusions based on short time series are problematic, leading to qualifications about periodicity, trends, and regime shifts. Starting in the 1980s, systematic research into climate change has considerably improved our understanding of regional warming and multiple threats to the Baltic Sea. Several aspects of regional climate and environmental changes and how they interact are, however, unknown and merit future research.
Buchteile zum Thema "Periodická regulace"
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Gilvear, D. J. „Suspended Solids Transport within Regulated Rivers Experiencing Periodic Reservoir Releases“. In Regulated Streams, 245–55. Boston, MA: Springer US, 1987. http://dx.doi.org/10.1007/978-1-4684-5392-8_16.
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Contopoulos, G., und E. Grousouzakou. „Regular and Irregular Periodic Orbits“. In The Dynamical Behaviour of our Planetary System, 33–56. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-011-5510-6_3.
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Roussarie, Robert. „Bifurcations of Regular Limit Periodic Sets“. In Bifurcation of Planar Vector Fields and Hilbert’s Sixteenth Problem, 51–90. Basel: Birkhäuser Basel, 1998. http://dx.doi.org/10.1007/978-3-0348-8798-4_4.
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Roussarie, Robert. „Bifurcations of Regular Limit Periodic Sets“. In Bifurcations of Planar Vector Fields and Hilbert's Sixteenth Problem, 51–90. Basel: Springer Basel, 1998. http://dx.doi.org/10.1007/978-3-0348-0718-0_4.
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Celletti, Alessandra. „Regular and Chaotic Dynamics of Periodic and Quasi-Periodic Motions“. In Space Manifold Dynamics, 113–32. New York, NY: Springer New York, 2009. http://dx.doi.org/10.1007/978-1-4419-0348-8_3.
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Banakh, Liudmila Ya, und Mark L. Kempner. „Vibrations of Regular Systems with Periodic Structure“. In Foundations of Engineering Mechanics, 41–78. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-03126-7_3.
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Inoue, Yusuke, Kenji Hashimoto und Hiroyuki Seki. „Semidirect Product Decompositions for Periodic Regular Languages“. In Developments in Language Theory, 173–88. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-66159-4_13.
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Belyakov, Vladimir. „Approximate Description of Interaction of Radiation with Regular Media“. In Diffraction Optics of Complex-Structured Periodic Media, 25–39. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-319-43482-7_2.
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Nakatani, Naoki, Jia-Jia Zheng und Shigeyoshi Sakaki. „Approach of Electronic Structure Calculations to Crystal“. In The Materials Research Society Series, 209–55. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-0260-6_11.
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AbstractNowadays, the importance of molecular crystals and solids with regular structures is increasing in both basic chemistry and applied fields. However, theoretical studies of those systems based on electronic structure theories have been limited. Although density functional theory (DFT) calculations using generalized gradient approximation type functional under periodic boundary condition is effective for such theoretical studies, we need some improvements for calculating the dispersion interaction and the excited state of crystals. Accordingly, in this chapter, two methods for calculating the electronic structures of molecular crystals are discussed: cluster-model/periodic-model (CM/PM)-combined method and quantum mechanics/periodic-molecular mechanics (QM/periodic-MM) method. In the CM/PM-combined method, an infinite crystal system is calculated by the DFT method under periodic boundary condition, and important moieties, which are represented by CMs, are calculated by either DFT method with hybrid-type functionals or wave function theories such as the Møller–Plesset second-order perturbation theory (MP2), spin-component-scaled-MP2, and coupled-cluster singles and doubles theory with perturbative triples (CCSD(T)). This method is useful for gas adsorption into crystals such as metal–organic frameworks. In the QM/periodic-MM method, an important moiety is calculated using a QM method such as the DFT method with hybrid-type functionals and wave function theories, where the effects of the crystal are incorporated into the QM calculation via the periodic MM method using a classical force field. This method is useful for theoretical studies of excited states and chemical reactions. The applications of these methods in the following processes are described in this chapter: adsorption of gas molecules on metal–organic frameworks, chemical reactions in crystals, and luminescence of the crystals of transition metal complexes. To the best of our knowledge, the theoretical calculations conducted in this chapter show one of the successful approaches of electronic structure theories to molecular crystals, because of the reasonable and practical approximations.
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Awrejcewicz, J., A. V. Krysko, I. V. Papkova, N. P. Erofeev und V. A. Krysko. „Chaotic Dynamics of Structural Members Under Regular Periodic and White Noise Excitations“. In Lecture Notes in Computer Science, 25–32. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-57099-0_3.
Der volle Inhalt der QuelleKonferenzberichte zum Thema "Periodická regulace"
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Panfilova, Ekaterina V., Artem R. Ibragimov, Olesya M. Ibragimova, Konstantin R. Min'ko, Cao Van Hoa und Ilya O. Azarnin. „Technological Cycle of the Periodic Structures Controlled Formation Based on the Microparticle Regular Arrays“. In 2025 7th International Youth Conference on Radio Electronics, Electrical and Power Engineering (REEPE), 1–5. IEEE, 2025. https://doi.org/10.1109/reepe63962.2025.10970961.
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Annadorai, Karthik, und Adam Darwin. „Effect of THPS on Discharge Water Quality - a Lessons Learned Study“. In CORROSION 2010, 1–10. NACE International, 2010. https://doi.org/10.5006/c2010-10251.
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Abstract Biocides typically have an adverse impact on overboard water. THPS (tetrakishydroxymethyl phosphonium sulfate), one of the most commonly used biocides offshore has a similar effect on produced water. The effect of THPS on seawater used for hydrotesting and bulk storage is seldom studied and rarely documented. The effect of temperature, pH, water depth, dissolved oxygen concentration and various ions in the system is important to note. Once a certain volume of water is treated with any chemical, it is now deemed to be chemically treated seawater which cannot be discharged unless verified using the NOEC (No Observable Effect Concentration) testing method. This experience will provide a detailed understanding of the discharge of chemically treated seawater as well as the interaction of THPS with potential ions in the matrix. Additionally, regular sampling and associated analyses will be presented that demonstrate the degradation and half-life of the THPS molecule in varying temperatures. Periodic sampling of the THPS chemical in the seawater has provided a detailed understanding of the half-life degradation of the chemical. The interaction of the chemical with the cations present in the system and subsequent aversion to the neutralization reaction with hydrogen peroxide has also been studied and presented.
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Mills, Zachary Grant, Basat Aziz und Alexander Alexeev. „Designing Active Surface Structures to Regulate Heat Transport in Microchannels“. In ASME 2012 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/smasis2012-8121.
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We used three dimensional computer simulations to examine heat transport in a microchannel that encompasses a periodic array of biomimetic synthetic cilia. We modeled two different configurations of tilted cilia. Both configurations consisted of a grid of evenly spaced cilia with length L and square cross-section 0.1L×0.1L. The cilia were spaced at a distance δx between cilium rows and the inter-cilia spacing in the rows was fixed at δz = 0.25L for one configuration and δz = 0.5L for the other. The channel was filled with a viscous fluid and its top and bottom walls were maintained at different temperatures. The cilia were attached to the bottom channel wall at a specific angle and were actuated by a periodic external force applied vertically to their free ends. The periodical beating of cilia induces fluid mixing inside the fluid that facilitates heat transport. To model this multi-component system, we employed a thermal lattice Boltzmann model coupled with the lattice spring model. In order to investigate how the active cilia affect the heat transfer between the channel walls we varied three parameters in the system. Specifically, we systematically changed the tilt of the cilia, the spacing between cilia and the oscillation frequency of the cilia. Our investigations have allowed us to determine the optimal conditions for using cilia to increase the heat flux from a heated surface. Our findings could be useful for developing new methods for temperature control in microscale devices.
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Medeiros e Sa, Asla, Luiz Henrique de Figueiredo und Jose Ezequiel Soto Sanchez. „Synthesizing Periodic Tilings of Regular Polygons“. In 2018 31st SIBGRAPI Conference on Graphics, Patterns and Images (SIBGRAPI). IEEE, 2018. http://dx.doi.org/10.1109/sibgrapi.2018.00009.
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Sánchez, José Ezequiel Soto, Asla Medeiros e Sá und Luiz Henrique de Figueiredo. „On periodic tilings with regular polygons“. In Anais Estendidos da Conference on Graphics, Patterns and Images. Sociedade Brasileira de Computação - SBC, 2021. http://dx.doi.org/10.5753/sibgrapi.est.2021.20025.
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The thesis describes a simple integer-based computational representation for periodic tilings of regular polygons using complex numbers, which is now the state of the art for these objects. Several properties of this representation are discussed, including elegant and efficient strategies for acquisition, reconstruction, rendering, and automatic crystallographic classification by symmetry detection. The thesis also describes a novel strategy for the enumeration and generation of triangle-square tilings via equivalence with edge-labeled hexagonal graphs. The equivalence provide triangle-square tilings with an algebraic structure that allows an unfolding interpretation.
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Luo, Albert C. J., und Lidi Chen. „Grazing Bifurcation and Periodic Motion Switching in a Piecewise Linear, Impacting Oscillator Under a Periodical Excitation“. In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-80076.
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The grazing bifurcation and periodic motion switching of the harmonically forced, piecewise linear system with impacting are investigated. The generic mappings based on the discontinuous boundaries are introduced. Furthermore, the mapping structures are developed for the analytical prediction of periodic motions in such a system. The local stability and bifurcation conditions for specified periodic motions are obtained. The regular and grazing, periodic motions are illustrated. The grazing is the origin of the periodic motion switching for this system. Such a grazing bifurcation cannot be estimated through the local stability analysis. This model is applicable to prediction of periodic motions in nonlinear dynamics of gear transmission systems.
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Paredes, Victor, und Ayonga Hereid. „Dynamic Locomotion of a Lower-Limb Exoskeleton Through Virtual Constraints Based ZMP Regulation“. In ASME 2020 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/dscc2020-3170.
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Abstract Robotic lower-limb exoskeletons have the potentials to assist individuals with paraplegia to perform normal ambulatory functions and to provide exceptional health benefits. While modern-day hardware for exoskeletons is becoming more powerful, there are still significant challenges in implementing a practical exoskeleton motion control framework that helps paraplegic individuals to complete regular ambulatory tasks stably, safely, and efficiently without the use of arm-crutches. Inspired by the current development in dynamic walking controllers for a bipedal robot, this paper proposes a Hybrid Zero Dynamics (HZD) based control approach for powered lower-limb exoskeletons to achieve dynamic hand-free locomotion. Due to the unmodelled dynamics and exerted forces from the user upon the exoskeleton, the model-based approaches such as Hybrid Zero Dynamics struggles when implementing on the actual hardware. In this paper, we systematically formulate a virtual-constraints-based regulation framework in order to robustly stabilize the system around a stable periodic gait within the HZD framework. This regulator is then used to regulate the zero moment point (ZMP) to improve the lateral stability of the bipedal robot by indirectly regulating the center of mass (CoM) position of the exoskeleton due to the lack of available force sensors at the bottom of the feet. The proposed approach presents a general structure with which the virtual constraints can be heuristically regulated to satisfy the stability condition imposed by the ZMP criteria without compromising the hybrid invariance of the walking gaits. The effectiveness of the regulators was demonstrated through stable walking of a powered lower-limb exoskeleton in simulation and experimentation.
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Lehman, Mario M., L. De Pasquale, D. Patrignani und J. L. Pombo. „Filtering a periodical component of a regular fractal using speckle“. In Lasers and Optics in Manufacturing III, herausgegeben von Philippe Refregier und Rolf-Juergen Ahlers. SPIE, 1997. http://dx.doi.org/10.1117/12.281292.
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Angulo, R. F. „Periodic and chaotic scattering of classical particles on regular surfaces“. In Modeling complex systems. AIP, 2001. http://dx.doi.org/10.1063/1.1386877.
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Alexeev, Alexander, Rajat Ghosh, Gavin A. Buxton, O. Berk Usta und Anna C. Balazs. „Using Actuated Cilia to Regulate Motion of Microscopic Particles“. In ASME 2010 First Global Congress on NanoEngineering for Medicine and Biology. ASMEDC, 2010. http://dx.doi.org/10.1115/nemb2010-13227.
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Marine animals use microscopic elastic filaments, or cilia, to capture food particles that are suspended in the surrounding solution [1, 2]. In the respiratory tract, active cilial layers facilitate the transport of particulates such as dust or mucous. These motile cilia experience the surrounding fluid as a highly viscous, low Reynolds number environment, where the effects of inertia are negligible [2]. Nevertheless, by oscillating in a periodic, time-irreversible manner, the elastic cilia can generate net currents within the fluid and thereby, effectively transport and direct microscopic particles. The behavior of these biological cilia provides a useful design concept for creating microfluidic devices where actuated “synthetic cilia” would regulate the movement of micrometer-sized particles, such as biological cells and polymeric microcapsules.
Berichte der Organisationen zum Thema "Periodická regulace"
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Vaughn, Tim. PR179-22600-R03 Evaluation of High Flow Sampler Technologies. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), September 2024. http://dx.doi.org/10.55274/r0000087.
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Operators may be obligated to measure certain emission sources for regulatory, reporting, or internal environmental and/or maintenance programs. high-flow samplers remain the most useful and accurate tool for direct measurement of fugitive and vented emissions in the field. Certain regulated sources require periodic measurement with a high-flow sampler; thus, their use is likely to continue even as new alternative technologies mature. Several new samplers are currently available commercially and development work on prototype units is ongoing. This report will describe the performance and user experience during a battery of tests performed in both laboratory and field-like settings. Two commercial units (AddGlobe GFM 2.0, and Semtech HiFlow 2) and one prototype unit (CSU OS-HFS V2) were tested.
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Vaughn, Tim. PR179-22600-R02 Evaluation of High Flow Sampler Technologies. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), September 2024. http://dx.doi.org/10.55274/r0000086.
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Operators may be obligated to measure certain emission sources for regulatory, reporting, or internal environmental and/or maintenance programs. High flow samplers remain the most useful and accurate tool for direct measurement of fugitive and vented emissions in the field. Certain regulated sources require periodic measurement with a high flow sampler; thus, their use is likely to continue even as new alternative technologies mature. Several new samplers are currently available commercially and development work on prototype units is ongoing. This report will describe the performance and user experience during a battery of tests performed in both laboratory and field-like settings. Two commercial units (AddGlobe GFM 2.0, and Semtech HiFlow 2) and two prototype units (CSU OS-HFS V2, and GRTgaz/RICE HFS Venturi V2) were tested.
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Lehtimaki, Susanna, Aisling Reidy, Kassim Nishtar, Sara Darehschori, Andrew Painter und Nina Schwalbe. Independent Review and Investigation Mechanisms to Prevent Future Pandemics: A Proposed Way Forward. United Nations University International Institute for Global Health, April 2021. http://dx.doi.org/10.37941/rr/2021/1.
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The COVID-19 pandemic has created enormous challenges for national economies, livelihoods, and public services, including health systems. In January 2021, the World Health Organization proposed an international treaty on pandemics to strengthen the political commitment towards global pandemic preparedness, control, and response. The plan is to present a draft treaty to the World Health Assembly in May 2021. To inform the design of a support system for this treaty, we explored existing mechanisms for periodic reviews conducted either by peers or an external group as well as mechanisms for in-country investigations, conducted with or without country consent. Based on our review, we summarized key design principles requisite for review and investigation mechanisms and explain how these could be applied to pandemics preparedness, control, and response in global health. While there is no single global mechanism that could serve as a model in its own right, there is potential to combine aspects of existing mechanisms. A Universal Periodic Review design based on the model of human rights treaties with independent experts as the authorized monitoring body, if made obligatory, could support compliance with a new pandemic treaty. In terms of on-site investigations, the model by the Committee on Prevention of Torture could lend itself to treaty monitoring and outbreak investigations on short notice or unannounced. These mechanisms need to be put in place in accordance with several core interlinked design principles: compliance; accountability; independence; transparency and data sharing; speed; emphasis on capabilities; and incentives. The World Health Organization can incentivize and complement these efforts. It has an essential role in providing countries with technical support and tools to strengthen emergency preparedness and response capacities, including technical support for creating surveillance structures, integrating non-traditional data sources, creating data governance and data sharing standards, and conducting regular monitoring and assessment of preparedness and response capacities.
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McCarthy, James, Jeffrey Panek und Tom McGrath. PR-312-12206-R02 FTIR Formaldehyde Measurement at Turbine NESHAP and Ambient Levels. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), April 2018. http://dx.doi.org/10.55274/r0011476.
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When natural gas is combusted, formaldehyde is formed as an intermediate product as methane is converted to CO2 during combustion. Formaldehyde is regulated by the U.S. EPA as a hazardous air pollutant (HAP) under National Emission Standards for Hazardous Air Pollutants (NESHAP) regulations, and both turbines and reciprocating engines are listed source categories where EPA is required to develop regulations. NESHAPs have been adopted for natural gas-fired combustion turbines and reciprocating internal combustion engines (RICE), with initial regulations in 2004 that included a 91 parts per billion (ppb) standard for new turbines at "major source" facilities. However, the Turbine NESHAP was "stayed" by EPA as the agency considered whether natural gas-fired turbines should be regulated (i.e., whether those turbines would be "delisted" or removed from the rule). In response to a legal challenge regarding EPA's failure to meet Clean Air Act mandated schedules, EPA recently indicated that it plans to initiate a required periodic review of the Turbine NESHAP and that review will also address the delisting request. The "residual risk and technology review" (RTR) for the Turbine NESHAP will likely be conducted in 2018. Revisions to the regulation may be proposed when that review process is complete. Formaldehyde is ubiquitous (e.g., naturally formed through atmospheric chemistry even if not directly emitted), and there is also the potential that atmospheric levels and atmospheric chemistry are not adequately understood. Earlier pipeline industry testing of turbine formaldehyde emissions using refined methods indicated exhaust formaldehyde below 100 ppb and near the method detection limit. Anecdotal data from that test program showed ambient levels comparable to turbine exhaust in some cases, with naturally occurring emissions from an adjacent corn field resulting in ambient concentrations higher than formaldehyde exhaust levels. Evidence of "high" ambient formaldehyde levels (relative to turbine exhaust) may provide context and a counterargument to restrictive formaldehyde regulations. Understanding turbine formaldehyde emissions as compared to ambient levels is challenged by the ability to measure formaldehyde concentrations less than 100 parts per billion (ppb). Extractive Fourier Transform Infrared (FTIR) methods were developed for combustion exhaust formaldehyde measurement. However, measuring the ultra-low levels from turbines, commensurate with the NESHAP standard, will likely pose challenges. This project measured ambient formaldehyde levels using FTIR testing for comparison to the NESHAP standard. Significant challenges for conducting such measurements are apparent, which presents technical questions related to the feasibility of implementing emissions tests for the Turbine NESHAP standard.
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Newton, Ronald, Joseph Riov und John Cairney. Isolation and Functional Analysis of Drought-Induced Genes in Pinus. United States Department of Agriculture, September 1993. http://dx.doi.org/10.32747/1993.7568752.bard.
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Drought is a common factor limiting timber production in the U.S. and Israel. Loblolly (Pinus taeda) and alleppo pine (Pinus halepensis) seedling survival is reduced when out planted, and growth and reproduction are often hindered by periodic droughts during later stages of tree development. Molecular and gene responses to drought stress have not been characterized. The objectives were to characterize drought-induced gene clones from these pines, to determine the effects of a growth regulator on drought tolerance, ABA levels, and drought-induced gene expression in alleppo pine, and to develop procedures for loblolly pine transformation. Nearly 20 cDNA clones influenced by gradual, prolonged drought stress have been isolated. Many of these have been shown to be induced by drought stress, whereas several others are down-regulated. These are the first drought-induced genes isolated from a pine species. Two genomic clones (lp5-1 and lp3-1) have been sequenced and characterized, and each has been found to be associated with a gene family. Clone lp5 appears to code for a cell wall protein, and clone lp3 codes for a nuclear protein. The former may be associated with changing the elastic properties of the cell wall, while the latter may be involved in signal transduction and/or protection from desiccation in the nucleus. Clone lp3 is similar to a drought-induced gene from tomato and is regulated by ABA. Several DNA sequences that are specific to induction during growth-retardation in alleppo pine by uniconazole have been identified. The active DNA species is now being identified. Promoters from genomic clones, lp3 and lp5, have been sequenced. Both are functional when fused with the gus reporter gene and transferred to other plant tissues as well as responding to a simulated drought stress. Through exodeletion analysis, it has been established that the promoter ABRE element of lp3 responds to ABA and that drought-induction of lp3 expression may also involve ABA. Stable tobacco transformants carrying either the lp5 or the lp3 promoter fused to a reporter gus gene have been obtained. The lp5lgus fusion was expressed at several stages of tobacco development and differentiation including the reproductive stage. There was no difference in phenotype between the transformants and the wild type. Embryogenesis procedures were developed for slash pine, but attempts to couple this process with gene transfer and plantlet transformation were not successful. Transformation of pine using Agrobacterium appears tractable, but molecular data supporting stable integration of the Agrobacterium-transferred gene are still inconclusive.
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Ahammad, Ronju, und Francisco X. Aguilar. Socio-economic indicators for the assessment of sustainability in the Swedish forest sector, and linkages with the national environmental quality objectives. SLU Future forests, Swedish University of Agricultural Sciences, 2024. http://dx.doi.org/10.54612/a.6cbejge10k.
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Sweden’s Environmental Quality Objectives (EQOs) have been adopted to help describe the environment the country wishes to achieve, and are a promise to future generations of clean air, a healthy living environment, and rich opportunities to enjoy nature. Here, we assessed selected socio-economic indicators adapted from the Montréal Process for the Conservation and Sustainable Management of Temperate and Boreal Forests (MP) to examine trends in the Swedish forest sector of direct relevance to the EQOs. We did this with the aim of raising awareness about important socio-economic dimensions related to the EQOs, and to explore the linkages between the EQOs and the forest bioeconomy. We focused on the forest sector because of its central importance to meeting the EQOs, and fundamental social and economic roles it plays in Swedish society. The MP was chosen as our guiding framework because it was developed to assess national-level sustainable forest conservation and management, thus, incorporating critical economic, environmental and social dimensions. We applied a mixed methods approach based on a literature review, analyses of national and multilateral databases, and consultation with experts to identify and interpret selected indicators. We identified forest sector socio-economic indicators relevant to the EQOs related to forest property and ownership, economic value and consumption of wood and wood products, employment, wood energy, access to greenery, per capita forest availability, and cultural values. Interpretation of national-level indicators estimated for the 2000-2020 period point to overall progress toward maintaining forest conservation and production areas and a sector that has added substantial economic value through the processing of wood and wood products. Forests are an importance source of renewable energy and increasingly support the location of non-wood energy sources through the placement of wind power mills across forested lands. Downward trends were observed in fewer forest owners, a shrinking workforce, and per capita forest area which might be explained by processes of bequeathing, higher industry efficiencies and continued population growth. Selected indicators related to production forests, wood energy, per capita protected forests and cultural importance suggest these can directly support relevant EQOs including living forests, limited climate impact, rich plant and animal life. Through exports and hiring foreign workers, the Swedish forest sector has kept a direct linkage with the consumption of wood products abroad and in supporting economic wellbeing in lesser-developed nations through wages from forestry and non-wood seasonal employment, respectively. There is limited current information on cultural aspects such as heritage values and reindeer herding. Available data suggest a declining trend in damages to cultural remains within forest felling areas. We recommend regular and periodic assessment of the cultural and conservation values for Swedish forests to strengthen the ability to assess social and ecological sustainability relevant to the EQOs.
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PR-396-113704-R01 Automated Floating Roof Seal Integrity Reporting - Ph 1 - Reg Review Methods of Seal Gap. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), Februar 2012. http://dx.doi.org/10.55274/r0010755.
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Describes the development of an automated system that can effectively replace the currently regulated periodic in-service and out-of-service inspections of the Internal Floating Roofs (IFR) in Above ground Storage Tanks (ASTs). As a first step in this direction, it is important to review the current regulatory landscape and develop an understanding of how the regulators plan to evolve the compliance requirements and inspection procedures.