This thesis details the development of a custom autopilot system designed specifically for multi-agent robotic missions. The project was motivated by the need for a flexible autopilot system architecture that could be easily adapted to a variety of future multi-vehicle experiments. The development efforts can be split into three categories: algorithm and software development, hardware development, and testing and integration. Over 12,000 lines of C++ code were written in this project, resulting in custom flight and ground control software. The flight software was designed to run on a Gumstix Overo Fire(STORM) computer on module (COM) using a Linux Angstrom operating system. The flight software was designed to support the onboard GN&C algorithms. The ground control station and its graphical user interface were developed in the Qt C++ framework. The ground control software has been proven to operate safely during multi-vehicle tests, and will be an asset in future work. Two TSH GAUI 500X quad-rotors and one Gears Educational Systems SMP rover were integrated into an autonomous swarm. Each vehicle used the Gumstix Overo COM. The C-DUS Pilot board was designed as a custom interface circuit board for the Overo COM and its expansion board, the Gumstix Pinto-TH. While the built-in WiFi capability of the Overo COM served as a communication link to a central wireless router, the C-DUS Pilot board allowed for the compact and reliable integration of sensors and actuators. The sensors used in this project were limited to accelerometers, gyroscopes, magnetometers, and GPS. All of the components underwent extensive testing. A series of ground and flight tests were conducted to safely and gradually prove system capabilities. The work presented in this thesis culminated with a successful three-vehicle autonomous demonstration comprised of two quad-rotors executing a standoff tracking trajectory around a moving rover, while simultaneously performing GPS-based collision avoidance. / text

Research on multi-agent systems performing cooperative tasks has received considerable attention in recent years. Because multiple agents perform cooperative tasks in close proximity, the coordination control of multiple agents to avoid collisions holds one of the critical keys to mission success. The potential function approach has been extensively employed for collision avoidance, but it has one inherent limitation of local minimum. This dissertation proposes a new avoidance strategy for the issue of local minimum. The primary objective of this research is to construct novel potential-function-based control schemes that drive agents from their initial to the goal configurations while avoiding collision with other agents and obstacles. The control schemes enable agents to avoid being trapped at a local minimum by forcing them to exit from the regions that may contain a local minimum. This dissertation consists of three studies, each of which has different technical assumptions. In the first study, all-to-all communication ability among agents is assumed. In addition, each agent is assumed to a priori know the location of all obstacles. In the second study, all-to-all communication ability is again assumed, but each agent is assumed to determine the location of obstacles using a sensor with a limited sensing range. In the third study, limited communication ability is assumed (i.e., each agent exchanges information only with agents within its limited communication range), and each agent is assumed to determine the location of the obstacles using its sensor with a limited sensing range. Relative to existing solutions, the new control schemes presented here have three distinct advantages. First, our avoidance strategy can provide cost-efficient solutions in applications because agents will never be trapped at a local minimum. Second, our control signals are continuous, which allows agents to change their speed in a realistic manner that is consistent with their natural motion traits. Finally, our control scheme allows for setting the upper bound of the velocity of each agent, which guarantees that the speed of agents will never exceed a maximum speed limit. / text

Beijing courtyard is a traditional type of residence in Beijing, China. In ancient times, a courtyard would be occupied by a single, usually large family. Today, Beijing courtyard are still used as housing complexes, however, many lack modern facilities, and also the users of courtyard become multi-families, instead of one single big family. The overpopulation issue also changed the courtyard's appearance and function, reducing its formality, consistency and traditionality, because people living in courtyard started to add extra elements to meet their growing demands. Moreover, because the land value around courtyard is so high that governement can only provide a limited number of public toilet to people living in courtyard, which lead to a poor standard of hygiene in the traditional courtyard area. And also, there are other issues, like lacking necessary facilitiess, inconvenient transportation and negative aspect for historic preservation. In a word, there is a great protential to make people living in the traditional courtyard enjoy a better life. / text

The JavaFlow, a Java DataFlow Machine is a machine design concept implementing a Java Virtual Machine aimed at addressing technology roadmap issues along with the ability to effectively utilize and manage very large numbers of processing cores. Specific design challenges addressed include: design complexity through a common set of repeatable structures; low power by featuring unused circuits and ability to power off sections of the chip; clock propagation and wire limits by using locality to bring data to processing elements and a Globally Asynchronous Locally Synchronous (GALS) design; and reliability by allowing portions of the design to be bypassed in case of failures. A Data Flow Architecture is used with multiple heterogeneous networks to connect processing elements capable of executing a single Java ByteCode instruction. Whole methods are cached in this DataFlow fabric, and the networks plus distributed intelligence are used for their management and execution. A mesh network is used for the DataFlow transfers; two ordered networks are used for management and control flow mapping; and multiple high speed rings are used to access the storage subsystem and a controlling General Purpose Processor (GPP). Analysis of benchmarks demonstrates the potential for this design concept. The design process was initiated by analyzing SPEC JVM benchmarks which identified a small number methods contributing to a significant percentage of the overall ByteCode operations. Additional analysis established static instruction mixes to prioritize the types of processing elements used in the DataFlow Fabric. The overall objective of the machine is to provide multi-threading performance for Java Methods deployed to this DataFlow fabric. With advances in technology it is envisioned that from 1,000 to 10,000 cores/instructions could be deployed and managed using this structure. This size of DataFlow fabric would allow all the key methods from the SPEC benchmarks to be resident. A baseline configuration is defined with a compressed dataflow structure and then compared to multiple configurations of instruction assignments and clock relationships. Using a series of methods from the SPEC benchmark running independently, IPC (Instructions per Cycle) performance of the sparsely populated heterogeneous structure is 40% of the baseline. The average ratio of instructions to required nodes is 3.5. Innovative solutions to the loading and management of Java methods along with the translation from control flow to DataFlow structure are demonstrated. / text

High target utilisation sputtering (HiTUS) is a relatively new thin film deposition technique that generates a high density plasma remotely from the sputter target. This method has been employed firstly to investigate FePt and FePtN thin films for high density data storage media applications and secondly to investigate the production of a GMR/PZT hybrid structure (multi-ferroism) for improvements to magneto-resistive read-sensor devices in hard disk drives and potentially for other novel multi-ferroic applications. The magnetic and structural properties of FePt and FePtN films, prepared by the HiTUS method, on both silicon and glass substrates have been investigated before and after annealing at temperatures in the range of 300 to 800 ◦C. It is shown that during thermal annealing there is a degradation in magnetic properties of the FePt films at around 400 ◦C due to the formation of silicides as the thermal processing promotes the reaction of the film with the substrate. However, in the FePtN samples coercivity values continue to rise with annealing temperatures above 400 ◦C. XRD analysis confirms that silicide formation is suppressed in films containing nitrogen up to 800 ◦C. Using the HiTUS technique, there is evidence that L10 ordering of FePt has occured at annealing temperature of 400 ◦C with in plane and out of plane coercivities of 7180 Oe and 6300 Oe respectively. Finally, it is shown that HiTUS is capable of depositing ultra thin multilayer GMR structures onto a variety of substrates; silicon, glass, flexible kapton film and PZT. It is interesting to find that the GMR ratio obtained on kapton film (14.39 %) is almost as high as that on silicon (16.15 %), with much scope for improve- ment. Multi-ferroic composite films consisting of the GMR multilayer structure [Co(8 °A)/Cu(21 °A)]×20/Co(12 °A) on PZT substrates were fabricated and magneto- electric coupling effects explored. It was found that AC voltages applied across the composite GMR/PZT structure produced a marked decrease in the coercivity of the GMR layer. However, DC voltages did not produce any measurable magnetic effects. Careful investigation revealed that the reduction in coercivity observed during AC measurements was, in fact, due to sample heating effects.

With advances in imaging and communication systems, there is increased use of multi-dimensional images. Examples include multi-view image/video, hyperspectral image/video and dynamic volume imaging in CT/MRI/Ultrasound. These datasets consume even larger amounts of resources for transmission or storage compared to 2-D images. Hence, it is vital to have efficient compression methods for multi-dimensional images. In this dissertation, first, a JPEG2000 Part-2 compliant scheme is proposed for compressing multi-dimensional datasets for any dimension N>=3. Secondly, a novel view-compensated compression method is investigated for remote visualization of volumetric data. Experimental results indicate superior compression performance compared to state-of-the-art compression standards. Thirdly, a new scalable low complexity coder is designed that sacrifices some compression efficiency to get substantial gain in throughput. Potential use of the scalable low complexity coder is illustrated for two applications: Airborne video transmission and remote volume visualization.

Distributed simulations have been widely applied as the method to study complex systems which are analytically intractable and numerically prohibitive to evaluate. However it is not a trivia task to develop distributed simulations. Besides distributed simulations may introduce difficulties for analysis due to decentralized, heterogeneous data sources. It is important to integrate these data sources seamlessly for analysis. In applications for system design, it is required to explore the alternatives of hardware components, algorithms, and simulation models. How to enable these operations conveniently is critical for the distributed system as well. All these challenges raise the need of a workbench that facilitates rapid composition, evaluation, modification and validation of components in a distributed system.This dissertation proposes a platform for these challenges, which we refer to the SPEED-CS platform. The architecture of the platform consists of multiple layers that include network layer, component management layer, components layer, and modeling layer. It is a multi-agent system (MAS), containing static agents and mobile agents. The mobile agent is referred as the Data Exchange Agent, which is able to visit sub-simulations and has the intelligence to find the useful data for output analysis. Experiments show that the MAS requires much less network bandwidth than the "centralized" system does, in which simulations report data to output analyst.The application of the SPEED-CS platform is extended to handle systems with dynamic data sources. We demonstrate that the platform can be used for parallel reality applications where simulation parameters can be updated according to real-time sensor information. Data exchange agents are involved to manage the collection, dissemination, and analysis of data from dynamic data sources including simulations and/or physical systems.The SPEED-CS platform is also implemented to integrate simulations and optimizations. The system is able to provide services to facilitate distributed computing, event services, naming services, and component management. One of the important features is that the component sets can be updated and enlarged with different models adding in. This feature enables the platform to work as a testbed to explore alternatives of system designs.Finally we conclude this dissertation with several future research topics.

This thesis presents the development of calibration and data-reduction algorithms for non-conventional multi-hole pressure probes. The algorithms that have been developed for conventional 5- and 7-hole probes are not optimal for probes with port arrangements (on the probe tip) that are non-conventional. Conventional algorithms utilize the axisymmetry of the port distribution pattern to define the non-dimensional pressure coefficients. These coefficients are typically defined specifically for these patterns, but fail to correctly represent different patterns of port arrangements, such as patterns without axisymmetry or regularity. The algorithms introduced herein can handle any pattern of port arrangement, from axisymmetric and regular to random. Moreover, they eliminate the need to separate the measurement domain of a probe to "low-angle" and "high-angle" regimes, typical in conventional 5- and 7-hole-probe algorithms that require two different sets of pressure coefficient definitions and procedures. Additionally, the algorithms have been formulated such that they facilitate redundancy implementations, especially in applications where such redundancy is important, such as air-data systems. The developed algorithms are first applied to a non-conventional probe, a nearly omni-directional 18-hole probe, and demonstrate very high flow measurement accuracy. Subsequently, the algorithms were applied to a new 12-hole, nearly omni-directional, flow velocity measurement probe capable of measuring reversed flows. The new 12-hole design offers several advantages over a previously developed, 18-hole, nearly omni-directional probe. The probe is optimized in the sense that, regardless of the flow direction, it allows calculation of the 4 unknown flow quantities, i.e. the two flow angles, the velocity magnitude and the static pressure, with the minimum necessary number of holes/ports on the probe tip. This probe also has a non-conventional arrangement of its pressure ports and therefore the new calibration and data-reduction algorithms can be effectively employed. With theoretically generated pressure data for the 12-hole probe, the coefficient definitions are analyzed and found to be well-behaved.

Syftet med uppsatsen är att analysera Gunnar Sjöbloms modell om programrealisering utifrån ett fall, Östersjömiljardprojektet, samt att följa upp modellen med aspekten om Multi-level governance. Detta görs med hjälp av tre frågeställningar. För att uppfylla syftet har jag med hjälp av en textanalys bearbetat material hämtat från Rikslex, Riksdagens arkiv, i form av propositioner, motioner, betänkande, och protokoll. Den teoretiska utgångspunkten har tagits ifrån Gunnar Sjöbloms modell som bygger på partistrategi i ett flerpartisystem. Partiernas främsta mål är att uppnå programrealisering. För att åstadkomma detta krävs inflytande på tre arenor: väljararenan, den interna arenan och den parlamentariska arenan.Östersjömiljardprojektet var ett förslag i sysselsättningspropositionen 1995 som byggde på att en miljard kronor skulle ingå i en fond avsatt för att främja svensk export inom områdena livsmedel, energi, ömsesidigt kunskapsutbyte, stärkt infrastruktur samt samarbete för att miljöskydd runt Östersjön. De områden som ingår i projektet är nordvästra Ryssland, Estland, Lettland, Litauen samt Polen. Resultatet visar att Sjöbloms modell är hållbar för det valda fallet. För att avgöra om det är ett fall av multi-level governance krävs ytterligare forskning på vilka påtryckningar utanför den politiska arenan som var betydande för beslutet.

One of the applications where the use of robots can be beneficial is Wilderness Search and Rescue (WiSAR), which involves the search for a possibly mobile but non-trackable lost person (i.e., the target) in wilderness environments. A mobile target implies that the search area grows continuously and potentially without bound. This fact, combined with the presence of typically rugged, varying terrain and the possibility of inclement weather, poses a considerable challenge to human Search and Rescue (SAR) personnel with respect to the time and effort required to perform the search and the danger entailed to the searchers. Mobile robots can be advantageous in WiSAR due to their ability to provide consistent performance without getting tired and their lower susceptibility to harsh weather conditions compared to humans. Thus, a coordinated team of robots that can assist human SAR personnel by autonomously performing searches in WiSAR scenarios would be of great value. However, to date, a suitable multi-robot coordination methodology for autonomous search that can satisfactorily address the issues relevant to WiSAR is lacking. The objective of this Dissertation is, thus, to develop a methodology that can autonomously coordinate the search strategy of a multi-robot team in wilderness environments to locate a moving target that is neither continuously nor intermittently observed during the search process. Three issues in particular are addressed: (i) target-location prediction, (ii) robot deployment, and (iii) robot-path planning. The corresponding solution approaches devised to address these issues incorporate the influence of varying terrain that may contain a priori known and unknown obstacles, and deal with unique target physiology and psychology as well as found clues left behind by the target. The solution methods for these three tasks work seamlessly together resulting in a tractable MRC methodology for autonomous robotic WiSAR. Comprehensive simulations have been performed that validate the overall proposed methodology. Moreover, the tangible benefits provided by this methodology were further revealed through its comparison with an alternative search method.