Robotic Manipulator Control in the Presence of Uncertainty

openThis research focuses on the problem of manipulator control in the presence of uncertainty and aims to compare different approaches for handling uncertainty while developing robust and adaptive methods that can control the robot without explicit knowledge of uncertainty bounds. Uncertainty is a pervasive challenge in robotics, arising from various sources such as sensor noise, modeling errors, and external disturbances. Effectively addressing uncertainty is crucial for achieving accurate and reliable manipulator control. The research will explore and compare existing methods for uncertainty handling such as robust feedback linearization , sliding mode control and robust adaptive control. These methods provide mechanisms to model and compensate for uncertainty in the control system. Additionally, modified robust and adaptive control methods will be developed that can dynamically adjust control laws based on the observed states, without requiring explicit knowledge of uncertainty bounds. To evaluate the performance of the different approaches, comprehensive experiments will be conducted on a manipulator platform. Various manipulation tasks will be performed under different levels of uncertainty, and the performance of each control approach will be assessed in terms of accuracy, stability, and adaptability. Comparative analysis will be conducted to highlight the strengths and weaknesses of each method and identify the most effective approach for handling uncertainty in manipulator control. The outcomes of this research will contribute to the advancement of manipulator control by providing insights into the effectiveness of different approaches for uncertainty handling. The development of new robust and adaptive control methods will enable manipulators to operate in uncertain environments without requiring explicit knowledge of uncertainty bounds. Ultimately, this research will facilitate the deployment of more reliable and adaptive robotic systems capable of handling uncertainty and improving their performance in various real-world applications.This research focuses on the problem of manipulator control in the presence of uncertainty and aims to compare different approaches for handling uncertainty while developing robust and adaptive methods that can control the robot without explicit knowledge of uncertainty bounds. Uncertainty is a pervasive challenge in robotics, arising from various sources such as sensor noise, modeling errors, and external disturbances. Effectively addressing uncertainty is crucial for achieving accurate and reliable manipulator control. The research will explore and compare existing methods for uncertainty handling such as robust feedback linearization , sliding mode control and robust adaptive control. These methods provide mechanisms to model and compensate for uncertainty in the control system. Additionally, modified robust and adaptive control methods will be developed that can dynamically adjust control laws based on the observed states, without requiring explicit knowledge of uncertainty bounds. To evaluate the performance of the different approaches, comprehensive experiments will be conducted on a manipulator platform. Various manipulation tasks will be performed under different levels of uncertainty, and the performance of each control approach will be assessed in terms of accuracy, stability, and adaptability. Comparative analysis will be conducted to highlight the strengths and weaknesses of each method and identify the most effective approach for handling uncertainty in manipulator control. The outcomes of this research will contribute to the advancement of manipulator control by providing insights into the effectiveness of different approaches for uncertainty handling. The development of new robust and adaptive control methods will enable manipulators to operate in uncertain environments without requiring explicit knowledge of uncertainty bounds. Ultimately, this research will facilitate the deployment of more reliable and adaptive robotic systems capable of handling uncertainty and improving their performance in various real-world applications

Identifying worst case test vectors for FPGA exposed to total ionization dose using design for testability techniques

Electronic devices often operate in harsh environments which contain a variation of radiation sources. Radiation may cause different kinds of damage to proper operation of the devices. Their sources can be found in terrestrial environments, or in extra-terrestrial environments like in space, or in man-made radiation sources like nuclear reactors, biomedical devices and high energy particles physics experiments equipment. Depending on the operation environment of the device, the radiation resultant effect manifests in several forms like total ionizing dose effect (TID), or single event effects (SEEs) such as single event upset (SEU), single event gate rupture (SEGR), and single event latch up (SEL). TID effect causes an increase in the delay and the leakage current of CMOS circuits which may damage the proper operation of the integrated circuit. To ensure proper operation of these devices under radiation, thorough testing must be made especially in critical applications like space and military applications. Although the standard which describes the procedure for testing electronic devices under radiation emphasizes the use of worst case test vectors (WCTVs), they are never used in radiation testing due to the difficulty of generating these vectors for circuits under test. For decades, design for testability (DFT) has been the best choice for test engineers to test digital circuits in industry. It has become a very mature technology that can be relied on. DFT is usually used with automatic test patterns generation (ATPG) software to generate test vectors to test application specific integrated circuits (ASICs), especially with sequential circuits, against faults like stuck at faults and path delay faults. Surprisingly, however, radiation testing has not yet made use of this reliable technology. In this thesis, a novel methodology is proposed to extend the usage of DFT to generate WCTVs for delay failure in Flash based field programmable gate arrays (FPGAs) exposed to total ionizing dose (TID). The methodology is validated using MicroSemi ProASIC3 FPGA and cobalt 60 facility

Efficient and Virtualized Scheduling for OFDM-Based High Mobility Wireless Communications Objects

Services providers (SPs) in the radio platform technology standard long term evolution (LTE) systems are enduring many challenges in order to accommodate the rapid expansion of mobile data usage. The modern technologies demonstrate new challenges to SPs, for example, reducing the cost of the capital and operating expenditures while supporting high data throughput per customer, extending battery life-per-charge of the cell phone devices, and supporting high mobility communications with fast and seamless handover (HO) networking architecture. In this thesis, a variety of optimized techniques aimed at providing innovative solutions for such challenges are explored. The thesis is divided into three parts. The first part outlines the benefits and challenges of deploying virtualized resource sharing concept. Wherein, SPs achieving a different schedulers policy are sharing evolved network B, allowing SPs to customize their efforts and provide service requirements; as a promising solution for reducing operational and capital expenditures, leading to potential energy savings, and supporting higher peak rates. The second part, formulates the optimized power allocation problem in a virtualized scheme in LTE uplink systems, aiming to extend the mobile devices’ battery utilization time per charge. While, the third part extrapolates a proposed hybrid-HO (HY-HO) technique, that can enhance the system performance in terms of latency and HO reliability at cell boundary for high mobility objects (up to 350 km/hr; wherein, HO will occur more frequent). The main contributions of this thesis are in designing optimal binary integer programmingbased and suboptimal heuristic (with complexity reduction) scheduling algorithms subject to exclusive and contiguous allocation, maximum transmission power, and rate constraints. Moreover, designing the HY-HO based on the combination of soft and hard HO was able to enhance the system performance in term of latency, interruption time and reliability during HO. The results prove that the proposed solutions effectively contribute in addressing the challenges caused by the demand for high data rates and power transmission in mobile networks especially in virtualized resources sharing scenarios that can support high data rates with improving quality of services (QoSs)

Review: Management of anterior urethral strictures with buccal mucosa: Our pioneering experience

Urethral stricture management is a challenging surgery. Multiplicity of techniques means that none of them is ideal. No single technique is appropriate for all situations and the successful surgeon should have a store of operations to choose from according to each specific case. This review aims to provide an update on the different uses of buccal mucosal graft as a reconstructive and replacement tool for anterior urethral strictures management.Keywords: Anterior urethral strictures; Urethroplasty; Buccal mucosa graf

The photophysical properties of chromophores assembled into metal-organic framework thin-films

Metallorganische Gerüste (MOFs) sind poröse Hybridmaterialien, die aus einem Metallzentrum bestehen, verbunden über Koordinationsbindungen mit einem organischen Linker. Nahezu unendliche Möglichkeiten der Metall-Linker-Kombination haben bisher zu einer großen Anzahl von MOF-Strukturen (>100.000) mit unterschiedlichen Strukturtopologien geführt. Die Eigenschaften von MOFs können durch eine durchdachte Auswahl der Metallzentren und organischen Linker abgestimmt werden, um MOFs spezifisch für bedarfsgerechte Anwendungen zu entwickeln. Bezugnehmend auf die weit fortgeschrittenen Anwendungen, ist die Herstellung von Festkörper-MOFs mittels der herkömmlichen Solvothermal-Methode nicht immer zielführend. Heterogene Morphologie, schwächere Anbindung an das Substrat und eine hohe Fehlstellendichte , wie in Festkörper-MOFs vorhanden, beeinflussen stark die Struktur-Eigenschafts Korrelation. Ein Ansatz zur Herstellung monolithischer kristalliner MOFs mit gut kontrollierten Dicke ist das Schicht-für-Schicht (LbL – layer-by-layer) -Verfahren über das Flüssigphasen-Epitaxie-Technik. In dieser Arbeit habe ich diese Technik verwendet, um hochkristalline, monolithische und orientierte SURMOF Strukturen aufzubauen. Eine hier verwendete Art von organischem Linker nennt sich photoaktive Verbindungen. Die räumliche Anordnung dieser photoaktiven Moleküle in der SURMOF-Plattform lieferte also hervorragende photophysikalische Eigenschaften. In der vorliegenden Arbeit habe ich ein Bianthrylchromophor untersucht, das mit metallkoordinierenden Gruppen ausgestattet ist, um einen photolumineszierenden oberflächenverankerten MOF -Dünnfilm (SURMOF) auf Zn-bianthrylbasis zu konstruieren. Die Zn-bianthryl-SURMOF haben eine gestapelte 2D-Schichtstruktur, die bei Anregung mit ultraviolettem (UV) Licht eine Cyan-Lumineszenz zeigt. In Reaktion auf die verlängerte UV-Bestrahlung in der Umgebungsbedingungen, zeigte der SURMOF auf Zn-bianthrylbasis jedoch eine deutliche Änderung der optischen Eigenschaften des Grund- und des angeregten Zustands, ohne seine Kristallstruktur zu verlieren. Eine detaillierte spektroskopische Untersuchung unter Verwendung von UV-Vis, FTIR, Raman, EPR und NEXAFS zeigte die Bildung der stabilen oxidierten Produkte von Bianthryl (Endoperoxid-Bianthryl) im SURMOF. Die vorliegende Studie identifiziert die Schlüsselfaktoren des Bianthryloxidationsprozesses, die einen selbstsensibilisierten photochemischen Weg beinhalten. Auch redoxaktive metallorganische Gerüste (MOFs) auf Viologenbasis haben in den letzten Jahren unter dem Gesichtspunkt intelligenter optisch aktiver Materialien großes Interesse gefunden. Hier wird ein Dicarboxylat-funktionalisiertes Viologen, 1,1‵-Bis (4- (carbonsäure) phenyl) - [4,4‵-bipyridin] -1,1‵-diiumdichlorid (viologen), als Linker zum Aufbau von SURMOF-Dünnfilmen unter Verwendung eines Schicht-für-Schicht-Flüssigphasen-Epitaxie-Verfahrens hergestellt. Diese Technik erzeugt ein hochkristallines, orientiertes SURMOF-2 auf Viologenbasis. Der orientierte, monolithische, kristalline SURMOF-Dünnfilm zeigt im Vergleich zu den zuvor beschriebenen Pulver-MOFs auf Viologenbasis eine schnell reversible Photochromie. Die Photochromie im SURMOF wird mittels UV-Vis, EPR und XPS untersucht

Evaluation of Four Novel Imported and Egyptian Curly and Non-Curly Leafed Parsley Genotypes for Yield and Essential Oil Composition Under The Egyptian Sandy Soil Growing Conditions

Four novel parsley genotypes (Moskurl 2 Petra, Moskurl 2 KRA USA, Gewone Dai 3 Rial 10, and Bravour) were imported from Netherlands to be planted and evaluated along with the Egyptian local variety “Egyptian” in the sandy soil under the Middle Egypt growing conditions. Three of the four introduced genotypes are curly-leafed varieties and one is non-curly leafed “Gewone Dai 3 Rial 10” as well as the Egyptian is a non-curly leafed variety. The aims of this experiment were to evaluate and study the growth characteristics (e.g. plant height, plant fresh and dry weights and fresh yield of leaves/m2) and some chemical properties of these genotypes (e.g. TSS and essential oil contents, essential oil composition and leaves content of chlorophyll a, b, and carotenoids) after adaptation and growing during the two successive winter seasons of 2013/2014 and 2014/2015. All introduced genotypes grew very well under these conditions and showed a very acceptable vegetative growth, profitable yield and high levels of volatile oils rich in anticancer and flavor responsible compounds and their horticultural and chemical proprieties were compared with those of the Egyptian local variety. The obtained data are very promising for Egyptian parsley growers to produce these new imported varieties in order to meet the increasing demand of parsley fresh and dry processed products with different shapes and different tastes of the Egyptian and foreign markets

Wave Interaction With Epsilon-znd-Mu-Near-Zero (emnz) Platforms and Nonreciprocal Metastructures

The concept of metamaterials has offered platforms for unconventional tailoring and manipulation of the light-matter interaction. In this dissertation, we explore several concepts and designs within this scope. We investigate some of the electromagnetic characteristics of the concept of “static optics”, i.e., wave interaction with structures in which both the relative effective permittivity and permeability attain near-zero values at a given operating frequency and thus the spatial distributions of the electric and magnetic fields exhibit curl-free features, while the fields are temporally dynamic. Using such structures, one might in principle ‘open up’ and ‘stretch’ the space, and have regions behaving electromagnetically as ‘single points’ despite being electrically large. We study some of the wave-matter interaction in these platforms and suggest possible designs for implementation of such structures in different frequency regimes and experimentally verify our findings in the microwave regime. Another research direction that is explored in this dissertation is the development of some nonreciprocal metaplatforms. We investigate theoretically an approach through which one-way electromagnetic wave flow can be achieved using properly designed nonlinearity combined with structural asymmetry. The approach is rather general and applicable for any desired frequency regime and opens doors for high performance “electromagnetic diodes” and nonreciprocal metasurfaces and metastructures. We also theoretically study the usage of time-dependent materials in achieving wave flow isolation within plasmonic waveguides environments. We also provide physical remarks on our various findings

Median sternotomy in penetrating cardiac trauma , does it make a difference ?

Background: Studies comparing the outcomes of left lateral thoracotomy and median sternotomy in the management of penetrating cardiac trauma in the Egyptian setting are lacking, which motivated us to conduct the current study. This study aimed to compare the perioperative and short-term outcomes between median sternotomy and left anterior thoracotomy in the management of patients with penetrating cardiac injuries. Methods: A total of 40 patients with penetrating cardiac trauma were included: 34 were males (85%), and 6 were females (15%). The mean age was 35.00 ± 10.83 years. Patients were allocated into two groups: Group A (n= 20) was managed with median sternotomy, and Group B (n= 20) was managed with left lateral thoracotomy. The study outcomes included operative time, intraoperative blood loss, postoperative pain score, duration of mechanical ventilation, length of ICU stay, postoperative complications and mortality. Results: The right ventricle was the most common injury site (60% vs. 50%, p= 0.619 in Groups A and B, respectively). Left lateral thoracotomy was associated with longer operation times [3750 (1500 – 6000) vs. 185 (70 - 260) mins, p= 0.002]. Left lateral thoracotomy patients had longer ICU stays [5 (2 – 7) vs. 3 (2 – 5) days, p= 0.004] and hospital stays [7 (4 – 12) vs. 5 (4 – 7) days, p= 0.001]. There were no differences in wound infection, pericardial effusion, or mortality between the groups. The pain score was lower in the median sternotomy group postoperatively from day 2 to day 7. Conclusion: Median sternotomy was associated with a significant decrease in operation time, blood loss, pain score, duration of ICU stay, and hospitalization period. The median sternotomy approach could be preferred over the thoracotomy approach in patients with penetrating cardiac injury