1,064 research outputs found
Analysis of gradient projection anti-windup scheme
No full textThe gradient projection anti-windup (GPAW) scheme was recently proposed as an anti-windup method for nonlinear multi-input-multi-output systems/controllers, the solution of which was recognized as a largely open problem in a recent survey paper. This paper analyzes the properties of the GPAW scheme applied to an input constrained first order linear time invariant (LTI) system driven by a first order LTI controller, where the objective is to regulate the system state about the origin. We show that the GPAW compensated system is in fact a projected dynamical system (PDS), and use results in the PDS literature to assert existence and uniqueness of its solutions. The main result is that the GPAW scheme can only maintain/enlarge the exact region of attraction of the uncompensated system.Singapore. DSO National LaboratoriesUnited States. Air Force Office of Scientific Research (grant FA9550-08-1-0086
Geometric properties of gradient projection anti-windup compensated systems
No full textThe gradient projection anti-windup (GPAW) scheme was recently proposed as an anti-windup method for nonlinear multi-input-multi-output systems/controllers, which was recognized as a largely open problem in a recent survey paper. Here, we show that for controllers whose output equation depends only on its state, the GPAW compensated controller achieves exact state-output consistency when appropriately initialized. In a related paper analyzing the GPAW scheme on a simple constrained system, this property was crucial in proving that the GPAW scheme can only maintain/enlarge the exact region of attraction of the uncompensated system. When the nominal controller does not have the required structure, an arbitrarily close approximating controller can be constructed. Further geometric properties of GPAW compensated systems are then presented, which illuminates the role of the GPAW tuning parameter.United States. Air Force Office of Scientific Research (grant FA9550-08-1-0086)Singapore. DSO National Laboratorie
On approximate dynamic inversion and proportional-integral control
No full textApproximate dynamic inversion (ADI) has been established as a method to control minimum-phase, nonaffine-in-control systems. Previous results have shown that for single-input nonaffine-in-control systems, every ADI controller admits a linear proportional-integral (PI) realization that is largely independent of the nonlinear function that defines the system. This paper extends these previous results in three ways. First, we present an extension of ADI that renders the closed loop error dynamics independent of the reference model dynamics. It is then shown that the equivalence between the ADI and PI controllers only holds for the time response when applied to the exact system. Finally, key robustness properties of the two control approaches are compared using linear system techniques. These results indicate that the PI realization is preferable when accurate knowledge of the nonlinear system dynamics is not available, and that the ADI realization would be preferred if time delays are the major limitations in the system
Proportional-integral controllers for minimum-phase nonaffine-in-control systems
No full textWe show that stabilizing tracking proportional-integral (PI)
controllers can be constructed for minimum-phase nonaffine-in-control
systems. The constructed PI controller is an equivalent realization of
an approximate dynamic inversion controller. This equivalence holds
only for the time response when applied to the unperturbed system.
Even when restricted to unperturbed minimum-phase linear time invariant
systems, their closed loop robustness properties differ. This
shows that in general, properties that do not define the equivalence relation
for systems/controllers are not preserved under such equivalence
transformations.Singapore. DSO National LaboratoriesUnited States. Air Force Office of Scientific Research (AFOSR grant FA9550-08-1-0086
Interpretasi aksi teo-ecology dan transendentalisme terhadap pelestarian lingkungan
No full textThis research presents a reading of the aspects of religious transidentalism in presenting the narrative of environmental preservation. Certainly in that context, the author tries to illustrate with teo-ecology construction based on quranic insights. Therefore, man as a subject, occupies a wide space in realizing the idea of godliness and humanistics in managing the nature and environment that God has given. Result of this study provides a major argument against the meaning of the Quran as the basis of environmental Teo-Ecology which contributes the deepest contribution, so that environmental preservation is always encouraged. In addition, in environmental preservation is necessary also the construction of ecological ethics humanizes the environment itself, so that a balance arises there. Lastly, it is no less important to elicit an attitude of transcendentalism in man that as god's representative on Earth must have mentally managed the environment well
Identity and Friendship in Hsu-Ming Teo´s Behind the Moon (2000)
No full textIn her second novel, Behind the Moon (2000), Hsu-Ming Teo explores the identity construction of three teenage friends and how they defy the notion of the „ideal‟ Australian as a heterosexual, Protestant, white, English-speaking, Australian-born of British ancestry young adult person. Set in the western suburbs of Sydney in the 1990s, the three friends are an example of the multicultural society of the time: Justin Cheong, the son of a Chinese-Singaporean family who arrived in Australia with the Business Migration Programme; Tien Ho, a refugee girl of Chinese-Vietnamese and Afro-CajunCreole-American ancestry; and Nigel „Gibbo‟ Gibson, the son of an Anglo-Australian father and an English mother. The novel tackles different relations among these characters and their families during their teenage years and especially as young adults. This paper seeks to analyse the evolution of the identities of Justin, Tien and „Gibbo‟ through the notions of belonging, gender construction and sexuality. In order to do so, the main theories applied will be the insights on homosexuality and on masculinities of Maria Pallotta-Chiarolli (1995) and Raewyn W. Connell (1995) and Manuel Castellsʼ (2010) identity construction theor
Real-Time Motion Planning With Applications to Autonomous Urban Driving
No full textThis paper describes a real-time motion planning algorithm, based on the rapidly-exploring random tree (RRT) approach, applicable to autonomous vehicles operating in an urban environment. Extensions to the standard RRT are predominantly motivated by: 1) the need to generate dynamically feasible plans in real-time; 2) safety requirements; 3) the constraints dictated by the uncertain operating (urban) environment. The primary novelty is in the use of closed-loop prediction in the framework of RRT. The proposed algorithm was at the core of the planning and control software for Team MIT's entry for the 2007 DARPA Urban Challenge, where the vehicle demonstrated the ability to complete a 60 mile simulated military supply mission, while safely interacting with other autonomous and human driven vehicles.Defense Advanced Research Projects Agency (Program: Urban Challenge, DARPA Order No. W369/00, Program Code: DIRO
Massimo Cacciari y la onto-teo-logía
No full textEs tracta de presentar a un autor com Massimo Cacciari en el marc del que Heidegger va anomenar onto-teo-logia com aquella manera d’interpretar el pensament filosòfic (ontològic) i teològic des de els inicis de la filosofia fins a Nietzsche. Heidegger insisteix al llarg de la seva obra en allò que ha quedat per pensar: l’Ésser. Subratlla aquesta carència com quelcom que afecta al destí de l’ésser i a la pròpia finitud humana. La tradició ha deixat ‘impensada’ la diferència de l’ésser de l’existent i l’existent. Aquesta carència demana, per tant, un ‘pas enrere’ en el que situar de bell nou a la ‘metafísica’. Cacciari es situa en el mateix punt de partida que Heidegger, però el filòsof italià explora una via que va ser pràcticament oblidada per Heidegger: el neoplatonisme. Al llarg d’aquesta investigació veurem, per tant, com els màxims representants del que Heidegger va anomenar onto-teo-logia son tornats a pensar des de una òptica ‘nova’ per Massimo Cacciari. El nihilisme detectat per Heidegger com l’encadenament d’una ‘metafísica general’ i una ‘metafísica especial’ pot ser revisat des dels comentaris al Parmènides de Plató de la gran tradició neoplatònica. Cacciari comença des de Kant per, en una mena de regressió en el temps, tornar a aquell lloc que la filosofia reclama com ‘amor al Bé’ i que la Crítica kantiana hauria menyspreat com una ‘volada cap a un lloc ignot’. Es tracta de reivindicar, al parer de Cacciari, el lloc de la intuïció filosòfica sense oblidar el que el mateix Heidegger ja va detectar com a paradigma onto-teo-lògic. La teologia, des d’aquesta perspectiva neoplatònica, pot ser revisada per convertir-se en una digne dialogant de la filosofia. Els desenvolupaments teològics no poden ser entesos sense el que el neoplatonisme va plantejar en el seu insistent desenvolupament de les apories del Parmènides. L’idealisme post-kantià (Hegel, Fichte) es ‘criticat’ i rebutjat des de la filosofia positiva de Schelling.
També presentem en aquest treball la crítica d’Emmanuel Levinas a un pensament sobre Déu en els termes en els que Heidegger el va presentar, és a dir, un Déu pensat només en els termes de la onto-teo-logia. La present investigació es divideix, per tant, en dos parts fonamentals: Heidegger i el paradigma onto-teo-lògic com el desenvolupament especulatiu del nihilisme i la alternativa que E. Levinas proposa a aquest plantejament per considerar una possibilitat no ontològica sobre un pensament sobre Déu (l’Altre): una possibilitat ètica (el rostre de l’altre des del que ‘veure’ l’Altre) i una segona part on presentem la trilogia fonamental de Cacciari (Dell’Inizio, Della Cosa Ultima i Labirinto Filosofico) com a interrogació ‘especulativa’ de tall neoplatònic del paradigma detectat per Heidegger.
He afegit tres apèndixs que intenten posar de relleu altres maneres d’enfocar el tema plantejat. Un apèndix dedicat al pensament del teòleg Zizioulas, un segon apèndix dedicat a les objeccions que va suscitar l’obra (Dell’Inizio) de Cacciari a Itàlia i un altre dedicat al plantejament tomista sobre el tema des de l’òptica de E. Gilson.Se trata de presentar a un autor como Massimo Cacciari enmarcándolo en lo que Heidegger llamó la onto-teo-logía como aquella manera de interpretar el pensamiento filósófico (ontológico) y teológico desde los albores de la filosofía hasta Nietzsche. Heidegger insiste a lo largo de su obra en aquello que ha quedado ‘impensado’: el Ser. Subraya esta carencia como algo que afecta al destino del ‘ser’ y a la propia finitud humana. La tradición ha dejado ‘impensada’ la diferencia del ser del ente y el ente. Esta carencia requiere, por tanto, un ‘paso atrás’ en el que situar de nuevo a la ‘metafísica’. Cacciari se situa en el mismo punto de partida del que Heidegger partió, pero el filósofo italiano explora una vía que fue prácticamente olvidada por Heidegger: el neoplatonismo. A lo largo de esta investigación veremos, por tanto, como los máximos representantes de lo que Heidegger llamó onto-teo-logía son repensados desde una óptica ‘nueva’ por Massimo Cacciari. El nihilismo detectado por Heidegger como el encadenamiento de una ‘metafísica general’ y una ‘metafísica especial’ puede ser revisado desde los comentarios al Parménides de Platón de la gran tradición neoplatónica. Cacciari parte de Kant para, en una especie de regresión en el tiempo, volver a aquel lugar que en filosofía se reclama como ‘amor al Bien’ y que la Crítica kantiana habría despreciado como un ‘vuelo hacia un lugar ignoto’. Se trata de reivindicar, al parecer de Cacciari, el lugar de la intuición filosófica sin olvidar lo que el mismo Heidegger ya detectó como pardigma onto-teo-lógico. La teología, vista desde esta vertiente neoplatónica, puede ser revisitada para ser una ‘digna’ dialogante de la filosofía. Los desarrollos teológicos no pueden ser entendidos sin lo que el neoplatonismo planteó en su insistente desarrollo de las aporías del Parménides. El idealismo post-kantiano (Hegel, Fichte) es ‘criticado’ y ‘rechazado’ desde la filosofía positiva de Schelling.
Presentamos además la crítica de Emmanuel Levinas a un pensamiento sobre Dios en los términos en los que Heidegger lo presentó, es decir, un Dios sólo pensado en los términos de la onto-teo-logía. La presente investigación se divide, por tanto, en dos partes fundamentales: Heidegger y el paradigma onto-teo-lógico como el desarrollo especulativo del nihilismo y la alternativa que E. Levinas propone a tal planteamiento por considerar una posibilidad no ontológica sobre un pensamiento sobre Dios (el Otro): una posibilidad ética (el rostro del otro desde el que ‘ver’ al Otro) y una segunda parte donde presentamos la trilogía fundamental de Cacciari (Dell’Inizio, Della Cosa Ultima y Labirinto Filosofico) como un cuestionamiento ‘especulativo’ de corte neoplatónico del paradigma detectado por Heidegger.
He añadido tres apéndices que intentan poner de relieve otros modos de enfocar el tema planteado. Un apéndice dedicado al pensamiento del teólogo Zizioulas, un segundo apéndice dedicado a las objeciones que suscitó la obra (Dell’Inizio) de Cacciari en Italia y otro dedicado al planteamiento tomista sobre el tema desde la óptica de E. Gilson.It is my intention to present author Massimo Cacciari in relation to what Heidegger called onto-theo-logy, as one way of interpreting the philosophical (ontological) and theological thinking, from the dawn of philosophy to Nietzsche. Heidegger insists throughout his work on what has been “unthinkable”, that is to say, the Being. The philosopher emphasises this lack as something that affects the fate of the “being” and our human finitude. The tradition has left behind a gap, in terms of the difference between the being entity and the entity itself. This deficiency requires, therefore, a 'step back' in order to place 'metaphysics' again. Cacciari is positioned at the same starting point from which Heidegger departed, but the Italian philosopher explores a way that was almost forgotten by Heidegger: Neoplatonism. Throughout this investigation we will see, therefore, how the main referents of what Heidegger called onto-theo-logy are studied from a 'new' perspective by Massimo Cacciari. The nihilism detected by Heidegger as the continuum of 'general metaphysics' and 'special metaphysics' can be revised from the comments on Plato's Parmenides in the great neoplatonic tradition. Cacciari departs from Kant, in a sort of regression in time, back to the common place that in philosophy is defined as 'love of the Good' and Kant's Critique would have despised as a «flight to nowhere». We intend to claim, pointing at Cacciari's particular perception, the place for philosophical intuition, while taking into account what Heidegger himself conceived as the onto-theo-logical paradigm. Theology, viewed from this neoplatonic perspective, may be revisited to become a dialogical counterpart of philosophy. These theological developments cannot be understood without the insistent advances raised by Neoplatonism in the paradoxes of Parmenides. The post-Kantian Idealism (Hegel, Fichte) is 'criticized' and 'rejected' from the positive philosophy of Schelling.
We present here, furthermore, Emmanuel Levinas's criticism of the thinking about God in the way Heidegger had submitted it, that is to say, a God thought only in onto-theo-logical terms. This research will, therefore, consist of two major parts: Heidegger and the onto-theo-logical paradigm, as the speculative proposal of nihilism and the alternative proposed by E. Levinas, where he suggests a non-ontological approach to the idea of God (the Other one), i.e., an ethical approach (the face of someone else from which we can see the Other one); and a second part, where we will introduce the basic trilogy of Cacciari (Dell'Inizio, Della Cosa Ultima and Labirinto Filosofico), as a speculative neoplatonic questioning of the paradigm posited by Heidegger.
Finally, we have added three appendices with the attempt to emphasize other possible approaches to the issue proposed. An appendix is devoted to the thought of theologian Zizioulas; a second appendix deals with the objections raised to Cacciari's work, Dell'Inizio, in Italy; and the final appendix is devoted to the Thomist approach to our issue from E. Gilson's perspective
Gradient projection anti-windup scheme
No full textThesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 205-217).It is a well-recognized fact that control saturation affects virtually all practical control systems. It leads to controller windup, which degrades/limits the system's closed-loop performance, and may cause catastrophic failures if it induces instability. Anti-windup compensation is one of two main approaches to mitigate the effects of windup, and is conceptually and practically attractive. For the idealized case of constrained linear time invariant (LTI) plants driven by LTI controllers, numerous anti-windup schemes exist. However, most practical control systems are inherently nonlinear, and anti-windup compensation for nonlinear systems remains largely an open problem. To this end, we propose the gradient projection anti-windup (GPAW) scheme, which is an extension of the conditional integration method to multi-input-multi-output (MIMO) nonlinear systems, using Rosen's gradient projection method for nonlinear programming. It achieves controller state-output consistency by projecting the controller state onto the unsaturated region induced by the control saturation constraints. The GPAW-compensated controller is a hybrid controller defined by the online solution to either a combinatorial optimization subproblem, a convex quadratic program, or a projection onto a convex polyhedral cone problem. We show that the GPAW-compensated system is obtained by modifying the uncompensated system with a passive operator. Qualitative weaknesses of some existing anti-windup results are established, which motivated a new paradigm to address the anti-windup problem. It is shown that for a constrained first order LTI plant driven by a first order LTI controller, GPAW compensation can only maintain/enlarge its region of attraction (ROA). In this new paradigm, we derived some ROA comparison and stability results for MIMO nonlinear as well as MIMO LTI systems. The thesis is not that the GPAW scheme solves a centuries-old open problem of immense practical importance, but rather, that it provides a potential path to a solution. We invite the reader to join us in this quest at the confluence of nonlinear systems, hybrid systems, projected dynamical systems, differential equations with discontinuous right-hand sides, combinatorial optimization, convex analysis and optimization, and passive systems.by Chun Sang Justin Teo.Sc.D
Overcoming the biological barriers to intravenous delivery of stem cells and drugs for the treatment of vascular-related diseases
No full textDefective vasculature is one of the hallmarks of many diseases ranging from restricted blood flow in ischemia to abnormal blood vessel growth in cancer. Intravenous administration is particularly beneficial to patients with vascular-related diseases which are not easily accessible by the conventional methods. Therapeutics delivered via this route, however, must overcome the barriers along the way from the entry into the bloodstream to the target destination. To maximize the therapeutic efficacy, this dissertation investigates the use of polymeric nanoparticles to improve the transport of intravenously administered therapeutics and their accumulation in the diseased sites.
The first part of this dissertation focuses on the delivery of mesenchymal stem cells to ischemic tissue. Chapter 2 presents the use of nanoparticles capable of enhancing the ability of stem cells to migrate across defective vascular walls. The surface of stem cells was tethered with particles that sustainably released stromal cell-derived factor-1α. Intravenously injected stem cells consequently exhibited a higher migration ability to ischemic muscle. The strategy of surface tethering was then applied towards protecting stem cells in the oxidative diseased sites, as presented in Chapter 3. The nanoparticles are devised to rapidly discharge antioxidant epigallocatechin gallate in response to elevated levels of hydrogen peroxide. The stem cells survived in sub-lethal concentrations of hydrogen peroxide and maintained their angiogenic potential in vivo.
The second part of this dissertation looks at the delivery of doxorubicin to cancer cells. Chapter 4 presents the design strategies of nanoparticles for an enhanced release of entrapped doxorubicin within cancer cells. By incorporating moieties sensitive to the intracellular signals of cancer cells, drug release from the particles was significantly accelerated, giving rise to superior in vivo antitumor efficacy. Ultimately, the results of this dissertation will greatly contribute to improving the therapeutic outcome of numerous vascular-related diseases.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2020-08-01The student, Jyeyng Teo, accepted the attached license on 2018-07-02 at 15:47.The student, Jyeyng Teo, submitted this Dissertation for approval on 2018-07-02 at 16:05.This Dissertation was approved for publication on 2018-07-06 at 08:58.DSpace SAF Submission Ingestion Package generated from Vireo submission #12703 on 2018-09-27 at 11:34:02Made available in DSpace on 2018-09-27T16:47:16Z (GMT). No. of bitstreams: 2
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