Physical dynamic simulation of shipboard power system components in a distributed computational environment

Shipboard power systems have different characteristics than the utility power systems. In the Shipboard power system it is crucial that the systems and equipment work at their peak performance levels. One of the most demanding aspects for simulations of the Shipboard Power Systems is to connect the device under test to a real-time simulated dynamic equivalent and in an environment with actual hardware in the Loop (HIL). The real time simulations can be achieved by using multi-distributed modeling concept, in which the global system model is distributed over several processors through a communication link. The advantage of this approach is that it permits the gradual change from pure simulation to actual application. In order to perform system studies in such an environment physical phase variable models of different components of the shipboard power system were developed using operational parameters obtained from finite element (FE) analysis. These models were developed for two types of studies low and high frequency studies. Low frequency studies are used to examine the shipboard power systems behavior under load switching, and faults. High-frequency studies were used to predict abnormal conditions due to overvoltage, and components harmonic behavior. Different experiments were conducted to validate the developed models. The Simulation and experiment results show excellent agreement. The shipboard power systems components behavior under internal faults was investigated using FE analysis. This developed technique is very curial in the Shipboard power systems faults detection due to the lack of comprehensive fault test databases. A wavelet based methodology for feature extraction of the shipboard power systems current signals was developed for harmonic and fault diagnosis studies. This modeling methodology can be utilized to evaluate and predicate the NPS components future behavior in the design stage which will reduce the development cycles, cut overall cost, prevent failures, and test each subsystem exhaustively before integrating it into the system.

DESEO: an active vision system for detection, tracking and recognition

[EN]In this paper, a basic conceptual architecture aimed at the design of Computer Vision System is qualitatively described. The proposed architecture addresses the design of vision systems in a modular fashion using modules with three distinct units or components: a processing network or diagnostics unit, a control unit and a communications unit. The control of the system at the modules level is designed based on a Discrete Events Model. This basic methodology has been used to design a realtime active vision system for detection, tracking and recognition of people. It is made up of three functional modules aimed at the detection, tracking, recognition of moving individuals plus a supervision module.

An active vision system integrating fast and slow processes

[EN]This paper describes an Active Vision System whose design assumes a distinction between fast or reactive and slow or background processes. Fast processes need to operate in cycles with critical timeouts that may affect system stability. While slow processes, though necessary, do not compromise system stability if its execution is delayed. Based on this simple taxonomy, a control architecture has been proposed and a prototype implemented that is able to track people in real-time with a robotic head while trying to identify the target. In this system, the tracking module is considered as the reactive part of the system while person identification is considered a background task.

A C80 DSP-based active vision system for real-time tracking

[EN]Active Vision Systems can be considered as dynamical systems which close the loop around artificial visual perception, controlling camera parameters, motion and also controlling processing to simplify, accelerate and do more robust visual perception. Research and Development in Active Vision Systems [Aloi87], [Bajc88] is a main area of interest in Computer Vision, mainly by its potential application in different scenarios where real-time performance is needed such as robot navigation, surveillance, visual inspection, among many others. Several systems have been developed during last years using robotic-heads for this purpose...

Nuclei of Nearby Active Galaxies: NIR and Sub-mm Views and Finalizing the LINC-NIRVANA Fringe and Flexure Tracking System: Flexure and Temperature Behavior

The work presented in my thesis addresses the two cornerstones of modern astronomy: Observation and Instrumentation. Part I deals with the observation of two nearby active galaxies, the Seyfert 2 galaxy NGC 1433 and the Seyfert 1 galaxy NGC 1566, both at a distance of $\sim10$ Mpc, which are part of the Nuclei of Galaxies (NUGA) sample. It is well established that every galaxy harbors a super massive black hole (SMBH) at its center. Furthermore, there seems to be a fundamental correlation between the stellar bulge and SMBH masses. Simulations show that massive feedback, e.g., powerful outflows, in Quasi Stellar Objects (QSOs) has an impact on the mutual growth of bulge and SMBH. Nearby galaxies follow this relation but accrete mass at much lower rates. This gives rise to the following questions: Which mechanisms allow feeding of nearby Active Galactic Nuclei (AGN)? Is this feeding triggered by events, e.g., star formation, nuclear spirals, outflows, on $\sim500$ pc scales around the AGN? Does feedback on these scales play a role in quenching the feeding process? Does it have an effect on the star formation close to the nucleus? To answer these questions I have carried out observations with the Spectrograph for INtegral Field Observation in the Near Infrared (SINFONI) at the Very Large Telescope (VLT) situated on Cerro Paranal in Chile. I have reduced and analyzed the recorded data, which contain spatial and spectral information in the H-band ($1.45 \mic-1.85 \mic$) and K-band ($1.95 \mic-2.45 \mic$) on the central $10\arcsec\times10\arcsec$ of the observed galaxies. Additionally, Atacama Large Millimeter/Sub-millimeter Array (ALMA) data at $350$ GHz ($\sim0.87$ mm) as well as optical high resolution Hubble Space Telescope (HST) images are used for the analysis. For NGC 1433 I deduce from comparison of the distributions of gas, dust, and intensity of highly ionized emission lines that the galaxy center lies $\sim70$ pc north-northwest of the prior estimate. A velocity gradient is observed at the new center, which I interpret as a bipolar outflow, a circum nuclear disk, or a combination of both. At least one dust and gas arm leads from a $r\sim200$ pc ring towards the nucleus and might feed the SMBH. Two bright warm H$_2$ gas spots are detected that indicate hidden star formation or a spiral arm-arm interaction. From the stellar velocity dispersion (SVD) I estimate a SMBH mass of $\sim1.74\times10^7$ \msol. For NGC 1566 I observe a nuclear gas disk of $\sim150$ pc in radius with a spiral structure. I estimate the total mass of this disk to be $\sim5.4\times10^7$ \msol. What mechanisms excite the gas in the disk is not clear. Neither can the existence of outflows be proven nor is star formation detected over the whole disk. On one side of the spiral structure I detect a star forming region with an estimated star formation rate of $\sim2.6\times10^{-3}$ \msol\ yr$^{-1}$. From broad Br$\gamma$ emission and SVD I estimate a mean SMBH mass of $\sim5.3\times10^6$ \msol\ with an Eddington ratio of $\sim2\times10^{-3}$. Part II deals with the final tests of the Fringe and Flexure Tracker (FFTS) for LBT INterferometric Camera and the NIR/Visible Adaptive iNterferometer for Astronomy (LINC-NIRVANA) at the Large Binocular Telescope (LBT) in Arizona, USA, which I conducted. The FFTS is the subsystem that combines the two separate beams of the LBT and enables near-infrared interferometry with a significantly large field of view. The FFTS has a cryogenic system and an ambient temperature system which are separated by the baffle system. I redesigned this baffle to guarantee the functionality of the system after the final tests in the Cologne cryostat. The redesign did not affect any scientific performance of LINC-NIRVANA. I show in the final cooldown tests that the baffle fulfills the temperature requirement and stays $<110$ K whereas the moving stages in the ambient system stay $>273$ K, which was not given for the old baffle design. Additionally, I test the tilting flexure of the whole FFTS and show that accurate positioning of the detector and the tracking during observation can be guaranteed.

Response toolkit to provide an active response against intrusions using Ontology-Based IRS

Los sistemas de respuesta activa tienen por objetivo ejecutar una respuesta en contra de una intrusión de forma automática. Sin embargo, ejecutar una respuesta automáticamente no es una tarea trivial ya que el costo de ejecutar una respuesta podría ser más grande que el efecto que cause la intrusión propiamente dicha. También, el sistema debe contar con un amplio conjunto de acciones de respuesta y un algoritmo que seleccione la respuesta óptima. Este artículo propone un toolkit de respuestas que será integrado a un IRS basado en Ontologías para permitir la ejecución automática de la mejor respuesta cuando una intrusión es detectada. Se presenta un conjunto de respuestas basadas en host y basadas en red que pueden ser ejecutadas por el IRS, dicha ejecución es llevada a cabo mediante agentes basados en plugins que han sido distribuidos en la red. Finalmente, se realiza la verificación del sistema propuesto, tomando como caso de uso un ataque de defacement obteniéndose resultados satisfactorios.

Hybrid Power System Intelligent Operation and Protection Involving Distributed Architectures and Pulsed Loads

Efficient and reliable techniques for power delivery and utilization are needed to account for the increased penetration of renewable energy sources in electric power systems. Such methods are also required for current and future demands of plug-in electric vehicles and high-power electronic loads. Distributed control and optimal power network architectures will lead to viable solutions to the energy management issue with high level of reliability and security. This dissertation is aimed at developing and verifying new techniques for distributed control by deploying DC microgrids, involving distributed renewable generation and energy storage, through the operating AC power system. To achieve the findings of this dissertation, an energy system architecture was developed involving AC and DC networks, both with distributed generations and demands. The various components of the DC microgrid were designed and built including DC-DC converters, voltage source inverters (VSI) and AC-DC rectifiers featuring novel designs developed by the candidate. New control techniques were developed and implemented to maximize the operating range of the power conditioning units used for integrating renewable energy into the DC bus. The control and operation of the DC microgrids in the hybrid AC/DC system involve intelligent energy management. Real-time energy management algorithms were developed and experimentally verified. These algorithms are based on intelligent decision-making elements along with an optimization process. This was aimed at enhancing the overall performance of the power system and mitigating the effect of heavy non-linear loads with variable intensity and duration. The developed algorithms were also used for managing the charging/discharging process of plug-in electric vehicle emulators. The protection of the proposed hybrid AC/DC power system was studied. Fault analysis and protection scheme and coordination, in addition to ideas on how to retrofit currently available protection concepts and devices for AC systems in a DC network, were presented. A study was also conducted on the effect of changing the distribution architecture and distributing the storage assets on the various zones of the network on the system’s dynamic security and stability. A practical shipboard power system was studied as an example of a hybrid AC/DC power system involving pulsed loads. Generally, the proposed hybrid AC/DC power system, besides most of the ideas, controls and algorithms presented in this dissertation, were experimentally verified at the Smart Grid Testbed, Energy Systems Research Laboratory. All the developments in this dissertation were experimentally verified at the Smart Grid Testbed.

An Islanding Detection Method based on Impedance Estimation and Grid Identification for Grid-Tie Distributed Power Generation Systems

Power system policies are broadly on track to escalate the use of renewable energy resources in electric power generation. Integration of dispersed generation to the utility network not only intensifies the benefits of renewable generation but also introduces further advantages such as power quality enhancement and freedom of power generation for the consumers. However, issues arise from the integration of distributed generators to the existing utility grid are as significant as its benefits. The issues are aggravated as the number of grid-connected distributed generators increases. Therefore, power quality demands become stricter to ensure a safe and proper advancement towards the emerging smart grid. In this regard, system protection is the area that is highly affected as the grid-connected distributed generation share in electricity generation increases. Islanding detection, amongst all protection issues, is the most important concern for a power system with high penetration of distributed sources. Islanding occurs when a portion of the distribution network which includes one or more distributed generation units and local loads is disconnected from the remaining portion of the grid. Upon formation of a power island, it remains energized due to the presence of one or more distributed sources. This thesis introduces a new islanding detection technique based on an enhanced multi-layer scheme that shows superior performance over the existing techniques. It provides improved solutions for safety and protection of power systems and distributed sources that are capable of operating in grid-connected mode. The proposed active method offers negligible non-detection zone. It is applicable to micro-grids with a number of distributed generation sources without sacrificing the dynamic response of the system. In addition, the information obtained from the proposed scheme allows for smooth transition to stand-alone operation if required. The proposed technique paves the path towards a comprehensive protection solution for future power networks. The proposed method is converter-resident and all power conversion systems that are operating based on power electronics converters can benefit from this method. The theoretical analysis is presented, and extensive simulation results confirm the validity of the analytical work.

Distributed optimization and games over networks: a system theoretical perspective

Several decision and control tasks involve networks of cyber-physical systems that need to be coordinated and controlled according to a fully-distributed paradigm involving only local communications without any central unit. This thesis focuses on distributed optimization and games over networks from a system theoretical perspective. In the addressed frameworks, we consider agents communicating only with neighbors and running distributed algorithms with optimization-oriented goals. The distinctive feature of this thesis is to interpret these algorithms as dynamical systems and, thus, to resort to powerful system theoretical tools for both their analysis and design. We first address the so-called consensus optimization setup. In this context, we provide an original system theoretical analysis of the well-known Gradient Tracking algorithm in the general case of nonconvex objective functions. Then, inspired by this method, we provide and study a series of extensions to improve the performance and to deal with more challenging settings like, e.g., the derivative-free framework or the online one. Subsequently, we tackle the recently emerged framework named distributed aggregative optimization. For this setup, we develop and analyze novel schemes to handle (i) online instances of the problem, (ii) ``personalized'' optimization frameworks, and (iii) feedback optimization settings. Finally, we adopt a system theoretical approach to address aggregative games over networks both in the presence or absence of linear coupling constraints among the decision variables of the players. In this context, we design and inspect novel fully-distributed algorithms, based on tracking mechanisms, that outperform state-of-the-art methods in finding the Nash equilibrium of the game.

Human Herpesvirus Infections Of The Central Nervous System: Laboratory Diagnosis Based On Dna Detection By Nested Pcr In Plasma And Cerebrospinal Fluid Samples.

Infections of the central nervous systems (CNS) present a diagnostic problem for which an accurate laboratory diagnosis is essential. Invasive practices, such as cerebral biopsy, have been replaced by obtaining a polymerase chain reaction (PCR) diagnosis using cerebral spinal fluid (CSF) as a reference method. Tests on DNA extracted from plasma are noninvasive, thus avoiding all of the collateral effects and patient risks associated with CSF collection. This study aimed to determine whether plasma can replace CSF in nested PCR analysis for the detection of CNS human herpesvirus (HHV) diseases by analysing the proportion of patients whose CSF nested PCR results were positive for CNS HHV who also had the same organism identified by plasma nested PCR. In this study, CSF DNA was used as the gold standard, and nested PCR was performed on both types of samples. Fifty-two patients with symptoms of nervous system infection were submitted to CSF and blood collection. For the eight HHV, one positive DNA result-in plasma and/or CSF nested PCR-was considered an active HHV infection, whereas the occurrence of two or more HHVs in the same sample was considered a coinfection. HHV infections were positively detected in 27/52 (51.9%) of the CSF and in 32/52 (61.5%) of the plasma, difference not significant, thus nested PCR can be performed on plasma instead of CSF. In conclusion, this findings suggest that plasma as a useful material for the diagnosis of cases where there is any difficulty to perform a CSF puncture.

Teste de banco com carga continua para analise do volume de oxigenio (VO2) predito e analisado por tempo de esforço em pessoas treinadas (TRD), ativas (ATV) e destreinadas (DTR) a partir dos 13 anos : proposta de validação

Universidade Estadual de Campinas . Faculdade de Educação Física

Natural rubber latex used as drug delivery system in guided bone regeneration (GBR)

In this work, we propose natural rubber latex (NRL) membranes as a protein delivery system. For this purpose Bovine Serum Albumin (BSA) was incorporated into the latex solution for in vitro protein delivery experiments. Different polymerization temperatures were used, from -10 to 27 °C, in order to control the membrane morphology. These membranes were characterized by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), as well as the Lowry Method to measure the BSA release. SEM and AFM microscopy analysis showed that the number, size and distribution of pores in NRL membranes can be varied, as well as its overall morphology. We have found that the morphology of the membrane is the predominant factor for higher protein release, compared with pore size and number of pores. Results demonstrated that the best drug-delivery system was the membrane polymerized at RT (27 °C), which does release 66% of its BSA content for up to 18 days. Our results indicate that NRLb could be used in the future as an active membrane that could accelerate bone healing in GBR.

Reaction-diffusion stochastic lattice model for a predator-prey system

We have the purpose of analyzing the effect of explicit diffusion processes in a predator-prey stochastic lattice model. More precisely we wish to investigate the possible effects due to diffusion upon the thresholds of coexistence of species, i. e., the possible changes in the transition between the active state and the absorbing state devoid of predators. To accomplish this task we have performed time dependent simulations and dynamic mean-field approximations. Our results indicate that the diffusive process can enhance the species coexistence.

Analysis of mangrove forest succession, using sediment cores: a case study in the Cananéia -Iguape coastal system, São Paulo Brazil

Sediment cores are an essential tool for the analysis of the dynamics of mangrove succession. Coring was used to correlate changes in depositional environments and lateral sedimentary facies with discrete stages of forest succession at the Cananéia-Iguape Coastal System in southeastern Brazil. A local level successional pattern was examined based on four core series T1) a sediment bank; T2) a smooth cordgrass Spartina alterniflora bank; T3) an active mangrove progradation fringe dominated by Laguncularia racemosa, and; T4) a mature mangrove forest dominated by Avicennia schaueriana. Cores were macroscopically described in terms of color, texture, sedimentary structure and organic components. The base of all cores exhibited a similar pattern suggesting common vertical progressive changes in depositional conditions and subsequent successional colonization pattern throughout the forest. The progradation zone is an exposed bank, colonized by S. alterniflora. L. racemosa, replaces S. alterniflora as progradation takes place. As the substrate consolidates A. schaueriana replaces L. racemosa and attains the greatest structural development in the mature forest. Cores collected within the A. schaueriana dominated stand contained S. alterniflora fragments near the base, confirming that a smooth cordgrass habitat characterized the establishment and early seral stages. Cores provide a reliable approach to describe local-level successional sequences in dynamic settings subject to drivers operating on multiple temporal and spatial scales where spatial heterogeneity can lead to multiple equilibria and where similar successional end-points may be reached through convergent paths.

Er : YAG laser, ultrasonic system, and curette produce different profiles on dentine root surfaces: An in vitro study

Objective: The aim of the present study was to compare the in vitro effects of the Er:YAG laser, an ultrasonic system, and manual curette on dentine root surface by roughness and micro-morphological analysis. Materials and Methods: Thirty-six flattened bovine roots were randomly assigned to one of the following groups: group 1 (n = 12): Er: YAG laser ( 2940 nm), 120 mJ/pulse, 10 Hz, 8.4 J/cm(2); group 2 ( n = 12): ultrasonic system; and group 3 ( n = 12): manual curette. The mean surface roughness (Ra) of each sample was measured using a profilometer before and after the treatments. The micro-morphology of the treated and untreated ( control) root surfaces was evaluated with scanning electron microscopy (SEM) at 50 x and 1000 x magnification. Results: Analysis with the profilometer showed that for equal times of instrumentation, the smoothest surfaces were produced by the Er: YAG laser and the ultrasonic system, followed by the curette ( p < 0.05). Morphological analyses demonstrated that treatment with the Er: YAG laser produced some areas with an irregular surface, craters, and ablation of the intertubular dentin. The smear layer was removed and dentine tubules were opened by both curettes and the ultrasonic system. The micro-morphology of the dentine root surface after ultrasonic treatment, however, demonstrated randomly distributed areas cratering. Conclusion: All instruments increased the roughness of the dentine root surface after treatment; however, the curette produced rougher surfaces than the other devices. SEM analysis revealed distinct root surface profiles produced by the three devices.