Increasing Endurance of an Autonomous Robot using an Immune-Inspired Framework

This paper describes the implementation of an online immune-inspired framework to help increase endurance of an autonomous robot. Endurance is defined as the ability of the robot to exert itself for a long period of time. The immune-inspired framework provides such capability by monitoring the behavior of the robot to ensure continuous and safe behavior. The immune-inspired framework combines innate and adaptive immune inspired algorithms. Innate uses a dendritic cell based innate immune algorithm, and adaptive uses an instance based B-cell approach. Results presented in this paper shows that when the robot is implemented with the immune-inspired framework, health and survivability of a robot is improved, therefore increasing its endurance

AdS black holes with arbitrary scalar coupling

A general class of axionic and electrically charged black holes for a self-interacting scalar field nonminimally coupled to Einstein gravity with a negative cosmological constant is presented. These solutions are the first examples of black holes with an arbitrary nonminimal coupling $\xi$ in four dimensions. Moreover, due to the presence of two three-forms fields, the topology of the horizon of these black holes is planar. We discuss some properties of these solutions electing particular values of the nonminimal coupling parameter. A special case arises when $\xi=1/4$, for which the gravitational field is confined in a region close to the event horizon. We also show that these black holes emerge from stealth AdS configurations as the axionic fields are switched on, and that they can be generated through a Kerr-Schild transformation. Finally, in the appendix, we extend these results to arbitrary dimension.Comment: 23 page

Laser ignition of iso-octane air aerosols

Iso-octane aerosols in air have been ignited with a focused Nd:YAG laser at pressures and temperatures of 100kPa and 270K and imaged using schlieren photography. The aerosol was generated using the Wilson cloud chamber technique. The droplet diameter, gas phase equivalence ratio and droplet number density were determined. The input laser energy and overall equivalence ratio were varied. For 270mJ pulse energies initial breakdown occurred at a number of sites along the laser beam axis. From measurements of the shock wave velocity it was found that energy was not deposited into the sites evenly. At pulse energies of 32mJ a single ignition site was observed. Overall fuel lean flames were observed to locally extinguish, however both stoichiometric and fuel rich flames were ignited. The minimum ignition energy was found to depend on the likelihood of a droplet existing at the focus of the laser beam

Impact of EU-FDI on economic growth in Middle Eastern countries

This paper develops a simultaneous equations model to test the process of interaction between foreign direct investment, exports and economic growth in three Middle Eastern countries: Egypt, Jordan, Oman, and test for any possible feedback effects. Most of the FDI in these countries flows from the EU. The simultaneous equations model results suggest that higher rates of economic growth result in a greater inflow of foreign capital. The regression results also suggest that interest rate differentials exert a much stronger effect than economic growth on the attraction of foreign capital in the case of Egypt. However, this variable does not seem to play a significant role in the case of Oman. Moreover, the simultaneous equations model results suggest that there is a feedback effect in the relationship between economic growth and capital inflow in all sample countries. A greater inflow of foreign capital leads to growth in the exports of good and services. The expansion in exports leads to growth in GNP, which in turn, encourages the attraction of more foreign capital.peer-reviewe

Control of Solar Thermal Linear Fresnel Collector Plants in Single Phase and Direct Steam Generation Modes

Ein wesentlicher Unterschied erneuerbarer Energiequellen zu fossilen Energieträgern liegt in der zeitlichen Verfügbarkeit. Im Gegensatz zu fossil angetriebenen Prozessen lässt sich die Energiezufuhr nicht regeln. Dies stellt vor allem die Solarenergie vor eine wesentliche Herausforderung. Die Sonne als Energiequelle unterliegt nicht nur tages bzw. jahreszeitlichen Schwankungen, sie ist oft auch nicht vorhersehbar. Dieser scheinbar kleine Unterschied zur fossilen Energiegewinnung, hat zu weitreichenden Forschungsak tivitäten in verschiedenen Bereichen der Wissenschaft und des Ingenieurwesens geführt, darunter die Entwicklung von Speichertechnologien und hybrider Systeme, die Abbildung des dynamischen Verhaltens, insbesondere im Teillastbetrieb und nicht zu Letzt die entsprechende Ausarbeitung verschiedener Regelsysteme. Das Hauptziel der vorliegenden Arbeit ist die Entwicklung geeigneter Regelgesetze für solarthermische Anlagen um der intermittierenden Natur der Sonne als Energieressource gerecht zu werden. Eine gute Regelung erhöht den Solarertrag, reduziert Stillstände, bietet eine optimierte Wahl des Betriebspunktes und garantiert die Stabilität und Robustheit des Systems, mit der Personen und Anlagensicherheit als oberste Priorität. Die Thesis gliedert sich in zwei Hauptteile. Der erste Teil beinhaltet die Regelungstechnik konzentrierender, solarthermischer Systeme mit einphasigen Strömungen. Als wesentliche Regelgröße dient die Kollektoraustritttemperatur. Mehrere Regelsysteme wurden unter verschiedenen Rahmenbedingungen und Prozessanforderungen experimentell getestet. Eine erweiterte PID-Regelung mit geeigneten Vorsteuerungsschleifen zeigt sehr gute Resultate, zudem lässt sich die Gestaltung und Umsetzung des Regelsystems einfach halten. Der zweite Teil der Arbeit widmet sich dem Regelsystem im solaren Direktverdampfungsbetrieb. Hierbei ist die Hauptregelgröße der benötigte Dampfdruck an der Prozessschnittstelle. Im Direktverdampfungsbetrieb wird die Anlage als Mehrgrößenregelsystem betrachtet. Zwei Regelkonzepte wurden mit der vorliegenden Arbeit entwickelt und getestet. Eines der Konzepte basiert auf einer erweiterten PID-Regelung mit Vorsteuerung. Dieses wurde erfolgreich umgesetzt und unter Realbedingungen über mehrere Jahre intensiv getestet. Das zweite Konzept stützt sich auf die Theorie der modellbasierten, Modellprädiktive Regelung (MPC). Hierbei handelt es sich um ein komplexes, entwicklungsintensives, Regelkonzept. Der wesentliche Vorteil ist die universelle Anwendbarkeit, mit reduziertem Aufwand für Implementierung, Bewirtschaftung und Inbetriebnahme. Die vorliegende Thesis zeigt, dass sich trotz der komplexen Dynamik solarthermischer Grossanlagen mit den vorgeschlagenen Regelkonzepten eine zuverlässige, robuste und wartungsarme Energieversorgung bewerkstelligen lässt

Adaptive and Online Health Monitoring System for Autonomous Aircraft

Good situation awareness is one of the key attributes required to maintain safe flight, especially for an Unmanned Aerial System (UAS). Good situation awareness can be achieved by incorporating an Adaptive Health Monitoring System (AHMS) to the aircraft. The AHMS monitors the flight outcome or flight behaviours of the aircraft based on its external environmental conditions and the behaviour of its internal systems. The AHMS does this by associating a health value to the aircraft's behaviour based on the progression of its sensory values produced by the aircraft's modules, components and/or subsystems. The AHMS indicates erroneous flight behaviour when a deviation to this health information is produced. This will be useful for a UAS because the pilot is taken out of the control loop and is unaware of how the environment and/or faults are affecting the behaviour of the aircraft. The autonomous pilot can use this health information to help produce safer and securer flight behaviour or fault tolerance to the aircraft. This allows the aircraft to fly safely in whatever the environmental conditions. This health information can also be used to help increase the endurance of the aircraft. This paper describes how the AHMS performs its capabilities

Attitudes of Private Firms in GCC Countries Towards Employing Indian Nationals: A Case Study

This paper tries to find out how private firms engaged in different economic activities in GCC countries differ in terms of their preference ratings of various attributes of Indian employees

Rapidly reconfigurable optical phase encoder-decoders based on fiber Bragg gratings

We demonstrate the capacity for fast dynamic reconfiguration of optical code-division multiple access (OCDMA) phase en/decoders based on fiber Bragg gratings and a thermal phase-tuning technique. The tuning time between two different phase codes is measured to be less than 2 s. An OCDMA system using tunable-phase decoders is compared with a system using fixed-phase decoders and, although the system using fixed-phase decoders exhibits a shorter output autocorrelation pulsewidth and lower sidelobes, the system using tunable-phase decoders has advantages of flexibility and a more relaxed requirement on the input pulsewidth