998 research outputs found

    Towards a Global Controller Design for Guaranteed Synchronization of Switched Chaotic Systems

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    This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.In this paper, synchronization of identical switched chaotic systems is explored based on Lyapunov theory of guaranteed stability. Concepts from robust control principles and switched linear systems are merged together to derive a sufficient condition for synchronization of identical master-slave switched nonlinear chaotic systems and are expressed in the form of bilinear matrix inequalities (BMIs). The nonlinear controller design problem is then recast in the form of linear matrix inequalities (LMIs) to facilitate numerical computation by standard LMI solvers and is illustrated by appropriate examples

    Stabilization Based Networked Predictive Controller Design for Switched Plants

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    This is the author accepted manuscript. The final version is available from IEEE via the DOI in this record.Stabilizing state feedback controller has been designed in this paper for a switched DC motor plant, controlled over communication network. The switched system formulation for the networked control system (NCS) with additional switching in a plant parameter along with the switching due to random packet losses, have been formulated as few set of non-strict Linear Matrix Inequalities (LMIs). In order to solve non-strict LMIs using standard LMI solver and to design the stabilizing state feedback controller, the Cone Complementary Linearization (CCL) technique has been adopted. Simulation studies have been carried out for a DC motor plant, operating at two different sampling times with random switching in the moment of inertia, representing sudden jerks

    Parkinson\u27s Disease, Amantadine Hydrochloride Therapy and Dopa Metabolites

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    In an attempt to clarify the effect of amantadine hydrochloride therapy in Parkinson\u27s disease, dopa metabolites were measured in the urine of 15 patients who were taking this medication. The results indicated that patients on amantadine therapy had lower urinary levels of epinephrine plus norepinephrine than either normal individuals or parkinsonian patients not receiving amantadine. Patients who developed livedo reticularis during amantadine therapy showed a small but significant increase in urinary dopamine levels and a similar decrease in dopac levels, when compared to other patients on amantadine who did not develop livedo reticularis

    New multi-proxy record shows potential impacts of precipitation on the rise and ebb of Bronze Age and imperial Persian societies in southeastern Iran

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    The Achaemenids and Sasanian ‘Persian’ Empires were significant political, economic, and social forces in the Late Bronze Age and Late Antiquity Eurasia, respectively, which have left marks on the heritage of the Mediterranean and Middle Eastern world. While attention is often focused on military and political conditions when discussing the prosperity and decline of these imperial powers, their realms, which crossed a variety of environmental settings, were highly dependent on the predictability of rainfall that drove agriculture and effective provisioning. Here, we present a multi-proxy sedimentological, geochemical, and palynological record from a 2.5-m long peat deposit near the excavation site in Konar Sandal near Jiroft in southeastern Iran, covering 4000-850 cal yr BP. Around 3950 cal yr BP a wet period prevailed based on elemental ratios, stable C isotope, pollen, and diagnostic lipids. Between 3900 and 3300 cal yr BP, wet/semi-wet conditions developed with the appearance of Cerealia-type pollen. Dry and windy conditions followed (ca. 3300-2900 cal yr BP), which coincided with the Siberian anticyclones and climatic shifts developing in the Eastern Mediterranean region. Consequently, the Bronze Age settlements around Jiroft, dependent on agriculture, underwent a steady decline. A prolonged wet period followed (ca. 2900-2300 cal yr BP) with the abundance of Sparganium-type pollen and the aquatic lipid proxy (Paq). This change coincided with intensive agricultural practices and the flourishing of the powerful Median and Achaemenid empires. The shift to high Ti/Al ratios coeval with the lowest δ13COM values suggests an increase in aeolian activity and dry conditions ca. 2100-1650 cal yr BP. The Jiroft valley again experienced wet conditions between 1550 and 1300 cal yr BP, which overlapped with the economic prosperity of the middle to late Sasanian empire. The paleoenvironmental reconstruction indicates that wet periods and intensive agriculture coincide with the Persian empires' zenith, political influence, and economic affluence. Therefore, contextualized and detailed paleoenvironmental records are desirable to explore the interplay of political and climatic factors in the development and fragmentation of the ancient settlements and imperial powers in Eurasian history.1. Introduction 2. Geographical setting 3. Materials and methods 3.1. Sampling, magnetic susceptibility, and grain size analysis 3.2. Radiocarbon analyses 3.3. Elemental and mineralogical analyses 3.4. C/N and stable isotope analyses 3.4.1. Lipid extraction 3.5. Pollen analysis 4. Results 4.1. Age-depth model and chronology 4.2. Units 4.2.1. Unit 1 (U 1; 250-189 cm; ca. 4000-3550 cal yr BP) 4.2.2. Unit 2 (U 2; 189-164 cm; ca. 3550-3300 cal yr BP) 4.2.3. Unit 3 (U 3; 164-134 cm; ca. 3300-2900 cal yr BP) 4.2.4. Unit 4 (U 4; 134-106 cm; ca. 2900-2300 cal yr BP) 4.2.5. Unit 5 (U 5; 106-61 cm; ca. 2300-1550 cal yr BP) 4.2.6. Unit 6 (U 6; 61-10 cm; ca. 1550-850 cal yr BP) 5. Discussion 5.1. Paleoclimate preceding the decline of the Jiroft civilization 5.2. The Late Bronze Age decline in Jiroft 5.3. Rise and fall of the Persian Empire 5.3.1. The pre-Islamic period and recent times 6. Conclusion

    On an exact solution of the Thomas-Fermi equation for a trapped Bose-Einstein condensate with dipole-dipole interactions

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    We derive an exact solution to the Thomas-Fermi equation for a Bose-Einstein condensate which has dipole-dipole interactions as well as the usual s-wave contact interaction, in a harmonic trap. Remarkably, despite the non-local anisotropic nature of the dipolar interaction the solution is an inverted parabola, as in the pure s-wave case, but with a different aspect ratio. Various properties such as electrostriction and stability are discussed.Comment: 11 pages, 5 figure

    Project MOSI: rationale and pilot-study results of an initiative to help protect zoo animals from mosquito-transmitted pathogens and contribute data on mosquito spatio–temporal distribution change

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    Mosquito-borne pathogens pose major threats to both wildlife and human health and, largely as a result of unintentional human-aided dispersal of their vector species, their cumulative threat is on the rise. Anthropogenic climate change is expected to be an increasingly significant driver of mosquito dispersal and associated disease spread. The potential health implications of changes in the spatio-temporal distribution of mosquitoes highlight the importance of ongoing surveillance and, where necessary, vector control and other health-management measures. The World Association of Zoos and Aquariums initiative, Project MOSI, was established to help protect vulnerable wildlife species in zoological facilities from mosquito-transmitted pathogens by establishing a zoo-based network of fixed mosquito monitoring sites to assist wildlife health management and contribute data on mosquito spatio-temporal distribution changes. A pilot study for Project MOSI is described here, including project rationale and results that confirm the feasibility of conducting basic standardized year-round mosquito trapping and monitoring in a zoo environment
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