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Robust analysis and synthesis for uncertain negative-imaginary systemsSong, Zhuoyue January 2011 (has links)
Negative-imaginary systems are broadly speaking stable and square (equal number of inputs and outputs) systems whose Nyquist plot lies underneath (never touches for strictly negative-imaginary systems) the real axis when the frequency varies in the open interval 0 to ∞. This class of systems appear quite often in engineering applications, for example, in lightly damped flexible structures with collocated position sensors and force actuators, multi-link robots, DC machines, active filters, etc. In this thesis, robustness analysis and controller synthesis methods for uncertain negative-imaginary systems are explored. Two new reformulation techniques are proposed that facilitate both the robustness analysis and controller synthesis for uncertain negative-imaginary systems. These reformulations are based on the transformation from negative-imaginary systems to a bounded-real framework via the positive-real property. In the presence of strictly negative-imaginary uncertainty, the robust stabilization problem is posed in an equivalent H∞ control framework; similarly, a negative-imaginary robust performance analysis problem is cast into an equivalent μ-framework. The latter framework also allows robust stability analysis when the perturbations are a mixture of bounded-real and negative-imaginary uncertainties. The proposed two techniques pave the way for existing H∞ control and μ theory to be applied to robustness analysis and controller synthesis for negative-imaginary systems. In addition, a static state-feedback synthesis method is proposed to achieve robust stability of a system in the presence of strictly negative-imaginary uncertainties. The method is developed in the LMI framework, which can be solved efficiently using convex optimization techniques. The controller synthesis method is based on the negative-imaginary stability theorem: a positive feedback interconnection of two negative-imaginary systems is internally stable if and only if the DC loop gain is contractive and at least one of the systems in the interconnected loop is strictly negative-imaginary. Also, in order to handle non-strict negative-imaginary uncertainties, a strongly strictly negative-imaginary lemma is proposed that helps to ensure the strictly negative-imaginary property of the nominal closed-loop system for robustness. To this end, a state-space characterization for strictly negative-imaginary property is given for non-minimal systems where the conditions are convex and hence numerically attractive. The results in this thesis hence facilitate both the robustness analysis and controller synthesis for negative-imaginary systems that quite often arise in practical scenarios. In addition, they can be applied to quantify the worse-case performance for this class of systems. Therefore, the proposed results have important implications in controller synthesis for uncertain negative-imaginary systems that achieve not only robust stabilization but also robust performance.
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Scheduling, spectrum sensing and cooperation in MU-MIMO broadcast and cognitive radio systemsJin, Lina January 2012 (has links)
In this thesis we investigate how to improve the performance of MU-MIMO wireless system in terms of achieving Shannon capacity limit and efficient use of precious resource of radio spectrum in wireless communication. First a new suboptimal volume-based scheduling algorithm is presented, which can be applied in MU-MIMO downlink system to transmit signals concurrently to multiple users under the assumption of perfect channel information at transmitter and receiver. The volume-based scheduling algorithm utilises Block Diagonalisation precoding and Householder reduction procedure of QR factorisation. In comparison with capacity-based suboptimal scheduling algorithm, the volume-based algorithm has much reduced computational complexity with only a fraction of sum-rate capacity penalty from the upper bound of system capacity limit. In comparison with semi-orthogonal user selection suboptimal scheduling algorithm, the volume-based scheduling algorithm can be implemented with less computational complexity. Furthermore, the sum-rate capacity achieved via volume-based scheduling algorithm is higher than that achieved by SUS scheduling algorithm in the MIMO case. Then, a two-step scheduling algorithm is proposed, which can be used in the MU-MIMO system and under the assumption that channel state information is known to the receiver, but it is not known to the transmitter and the system under the feedback resource constraint. Assume that low bits codebook and high bits codebook are stored at the transmitter and receiver. The users are selected by using the low bits codebook; subsequently the BD precoding vectors for selected users are designed by employing high bits codebook. The first step of the algorithm can alleviate the load on feedback uplink channel in the MU-MIMO wireless system while the second step can aid precoding design to improve system sum-rate capacity. Next, a MU-MIMO cognitive radio (CR) wireless system has been studied. In such system, a primary wireless network and secondary wireless network coexist and the transmitters and receivers are equipped with multiple antennas. Spectrum sensing methods by which a portion of spectrum can be utilised by a secondary user when the spectrum is detected not in use by a primary user were investigated. A Free Probability Theory (FPT) spectrum sensing method that is a blind spectrum sensing method is proposed. By utilizing the asymptotic behaviour of random matrix based on FPT, the covariance matrix of transmitted signals can be estimated through a large number of observations of the received signals. The method performs better than traditional energy spectrum sensing method. We also consider cooperative spectrum sensing by using the FPT method in MU-MIMO CR system. Cooperative spectrum sensing can improve the performance of signal detection. Furthermore, with the selective cooperative spectrum sensing approach, high probability of detection can be achieved when the system is under false alarm constraint. Finally, spectrum sensing method based on the bispectrum of high-order statistics (HOS) and receive diversity in SIMO CR system is proposed. Multiple antennas on the receiver can improve received SNR value and therefore enhance spectrum sensing performance in terms of increase of system-level probability of detection. Discussions on cooperative spectrum sensing by using the spectrum sensing method based on HOS and receive diversity are presented.
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Modulation of Neuropeptide Release via Voltage-Dependent and -Independent Signaling in Isolated Neurohypophysial Terminals: a DissertationVelazquez-Marrero, Cristina M. 28 April 2008 (has links)
This thesis details my examination of several mechanisms for modulation of neuropeptide release via voltage-dependent and voltage-independent intraterminal signaling in isolated neurohypophysial terminals. The first part of this work characterizes depolarization-induced neuropeptide release in the absence of extracellular calcium. The goal of this project was to examine the relationship between depolarization-induced release of intracellular calcium stores and depolarization-secretion coupling of neuropeptides. We demonstrate that depolarization in the absence of extracellular calcium induced by either High K+ or electrical stimulation induces a rise in [Ca2+]i and subsequent neuropeptide release from Hypothalamic Neurohypophysial System (HNS) terminals. A portion of extracellular calcium-independent neuropeptide release is due to intraterminal calcium, but the remaining depolarization-induced release may be due to calcium-independent voltage-dependent (CIVD) release (Zhang and Zhou, 2002; Zhang et al., 2004; Yang et al., 2005). Nevertheless, our results clearly show that extracellular calcium is notnecessary for depolarization-induced neuropeptide secretion from these CNS terminals.
In addition, I investigated the role of internal calcium stores in mediating μ-opioid inhibition of voltage-gated calcium channels (VGCCs). Inhibition of VGCCs via μ-opioid agonists has been shown to reduce neuropeptide release in response to High K+ stimulation of isolated terminals (Bicknell et al., 1985b; Russell et al., 1993; van Wimersma Greidanus and van de Heijning, 1993; Munro et al., 1994; Ortiz-Miranda et al., 2003; Russell et al., 2003; Ortiz-Miranda et al., 2005). My findings show μ-opioid inhibition, of VGCC and High K+-mediated rise in [Ca2+]i, are via a voltage-independent diffusible second-messenger targeting release of calcium from ryanodine-sensitive stores, possibly mediated via the cyclic ADP ribose signaling pathway.
Furthermore, I detail a different intracellular messenger pathway mediating the κ-opioid inhibition of VGCC and High K+-mediated rise in [Ca2+]ii. In contrast to the μ-opioid inhibition, κ-receptor activation is coupled to a voltage-dependent membrane-delimited pathway. Inhibition of neuropeptide release via both endogenous and exogenous κ-opioid agonists has been extensively studied (Bicknell et al., 1985a; Nordmann et al., 1986a; Wammack and Racke, 1988; Munro et al., 1994; Ingram et al., 1996; Rusin et al., 1997a). My investigation shows that the κ-inhibition of VGCC is voltage-dependent and is furthermore, relieved within the context of a physiological burst of action potentials (APs). This physiologically-evoked, activity-dependent modulation of VGCC and subsequent release, represents an important mechanism for short-term synaptic plasticity at the level of the terminals. Given the ubiquitous nature of voltage-dependent G-protein signaling in the CNS, our results may prove important in understanding modulatory effects of specific bursting patterns throughout the CNS. In the last 30 years the neurohypophysial system has proven to be an excellent system to study the complexities of depolarization-secretion coupling (DSC). There have been many advances in our understanding of the underlying mechanisms involved and their physiological implications. The current work focuses on two important features of DSC; voltage and calcium. Although in many ways these two are intrinsically linked through VGCC activation, we have found that in isolated HNS terminals that is not always the case. We have further found that when voltage and calcium influx are linked during DSC, modulation by opioids may or may not be linked to activity-dependent relief depending on the opioid receptor activated. This finding has important implications in neuropeptide release during patterned stimulation in vivo. As I will discuss further, many factors play into the complexities of the regulatory mechanisms involving release. As investigations into this remarkable field continue, I hope to have contributed a valuable piece to the puzzle.
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Automatizace rozvodny VN s využitím řídicího systému COM600 a standardu IEC61850 / Medium voltage substation automation using control system COM600 and standard IEC61850Havelka, Tomáš January 2016 (has links)
This work deals with problematic of standard IEC61850, mainly with chapter IEC 61850-9-2 LE which is commonly known as Process bus communication. There are described advanced tools of the control system COM600 with detail description of their configuration in this work. It also deals with configuration of IEC 61850-9-2 LE with Relion family protection relays and its implementation to the control system COM600. The main aim of this work is focused on configuration of IEC 61850-9-2 standard with protection relays, configuration and detail description of COM600 advanced tools, description of Logic processor, further custom design and appliaction configuration global reset of Logic procesor in control system COM600.
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Ženský hlas v současné praxi historicky poučené interpretace barokní hudby v České republice / Female Voice in Contemporary Czech Practice of Historically Informed Interpretation of Baroque MusicJägerová, Monika January 2018 (has links)
This thesis explores specific ways of using female singing voice in subculture of historically informed performance of baroque music in the Czech republic. The thesis is based on principles of cultural theory and cultural analysis. Main source for my research were interviews from the years 2015 and 2016 held with female singers specialized in historically informed performance, and my own living experience first as voice student, later as a performer in the field of baroque music. I explore ways of fulfilling fundamental demand of the subculture for "historical authenticity" (which is usually defined as "how did the music sound at the time of its origin"). I come to key term of "naturalness" and I further explore how this concept is embodied by the singers, how it affects the sound of the voice and aesthetic expectations of the singers and also listeners. I put the experience of "authentic" and "natural" interpretation of baroque music in context of thinking about pleasure, especially in terms of jouissance and plaisir described by Roland Barthes.
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PERIPHERALLY RESTRICTED OPIOID CONJUGATES AND ITS USE AS PHARMACOLOGICAL PROBES AND POTENTIAL THERAPEUTICSTuhin, Md Tariqul Haque 01 January 2022 (has links)
Opioid-induced constipation (OIC) is one of the major adverse effects of opioid analgesics used by millions of patients each year. While progress has been made, there remains a significant unmet medical need in the treatment of OIC. Major gaps remain in our understanding of the role of the gastrointestinal tract and central nervous system (CNS) in precipitating OIC. For the last four decades, numerous investigations to study the sites of action of opioid analgesics have utilized peripherally acting mu-opioid receptor antagonists (PAMORAs), which have been incorrectly believed to have limited penetration across the blood-brain barrier (BBB). Several preclinical and clinical reports indicate that significant amounts of PAMORAs penetrate the BBB quite readily. As a result, the usage of current PAMORAs have resulted in misunderstandings of the role of the CNS and gastrointestinal tract in causing side effects such as opioid-induced constipation (OIC).
We have developed a transthyretin-based novel drug delivery approach for restricting the passage of small molecules across the BBB. Our approach involves endowing the opioid agonist/antagonist with the selective transthyretin ligand, AG10. The newly synthesized naloxone- and oxycodone-based conjugates have demonstrated superior peripheral selectivity, improved pharmacokinetics, and efficacy in rats compared to other clinically used PAMORAs. Here we present chemical synthesis, in vitro binding and stability studies, as well as pharmacokinetic and pharmacodynamic evaluations of the AG10-opioid conjugates in rats. Our AG10-based PAMORA allowed us to obtain new insights into the important role of mu-opioid receptors in the central nervous system (CNS) in causing constipation. Additionally, our results demonstrate for the first time that synergy between mu-opioid receptors in the central nervous system and the gastrointestinal tract is crucial to the understanding of OIC and the development of effective treatment regimens. These findings contradict prior ideas that OIC was caused by a mechanism that involves primarily the gastrointestinal mu-opioid receptors. Moreover, we confirmed our findings by a AG10-oxycodone conjugate, a peripherally restricted opioid agonist. This molecule demonstrated the predominant role of CNS in OIC precipitation.
The newly synthesized AG10-opioid conjugates represent a novel class of pharmacological probes that will aid in our understanding of OIC and other undesirable adverse effects of opioids. In addition, these conjugates have been evaluated for their potential therapeutic value in the preclinical studies. Collectively our approach to limit the BBB penetration of opioids will contribute to develop safer and more effective opioid medications.
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Long-Term Opiate-Induced Adaptations in Lateral Paracapsular Neurons of the Basolateral AmygdalaWerner, Sara Jane 09 April 2020 (has links)
Increases in basolateral amygdala (BLA) activity drive avoidance-seeking behavior that may be associated with stress induced drug seeking. Activity of BLA pyramidal neurons is regulated by local and paracapsular gamma aminobutyric acid (GABA) interneurons. The lateral paracapsular interneurons (LPCs) border the external capsule, receive dense cortical/thalamic input and provide feed-forward inhibition onto BLA principle neurons. The GABAergic LPCs also express high concentrations of g-protein coupled µ-opioid receptors (MORs). Therefore, the effects of opiates on LPC activity and local GABA release were examined. Fluorescently double labeled LPCs were observed in glutamate decarboxylase (GAD) 65-mcherry/GAD67-green fluorescent protein (GFP) transgenic mice. Whole-cell electrophysiology experiments demonstrated that acute exposure to [D-Ala2, N-Me-Phe4, Gly5-ol]-enkephalin (DAMGO; a synthetic selective MOR agonist), reduced LPC firing and spontaneous inhibitory postsynaptic current (sIPSC) frequency in LPCs, with no apparent effect on spontaneous excitatory currents (sEPSCs). Current injection induced firing in LPC neurons, but less effectively than in saline controls. Morphine-exposed mice (10mg/kg/day, across 5 days, 1-2 days off) had increased sIPSCs compared to saline-injected controls, as well as enhanced adenylyl cyclase (AC) activity. Together these data show that LPC neurons are a highly sensitive targets for opiate-induced inhibition, and that long-term opiate exposure results in impaired LPC excitability, possibly contributing to anxiety observed during opiate withdrawal.
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Šifrování telefonních hovorů / Encrypting Landlines Phone CommunicationVávra, Jakub January 2008 (has links)
This master's thesis is about making draft and implementing land-line phone call encryption using FITkit. The ultimate goal is to find suitable compression and encryption methods, implement or adapt them for FITkit board and create functional solution.
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Robust adaptive beamforming for clutter rejection on atmospheric radars / 大気レーダーのための適応的クラッター抑圧手法Hashimoto, Taishi 23 September 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第20034号 / 情博第629号 / 新制||情||109(附属図書館) / 33130 / 京都大学大学院情報学研究科通信情報システム専攻 / (主査)教授 佐藤 亨, 教授 守倉 正博, 教授 山本 衛 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM
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Adaptation of First-Person Narrative Literature: Revisiting <i>Kazoku gēmu</i> (1981) and <i>The Family Game</i> (1983)Zhang, Xiyue January 2019 (has links)
No description available.
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