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Aiding Navigation for Groups of Aircraft with Bearing and Distance MeasurementsOlsson, Mattias January 2018 (has links)
This thesis extends previous work on navigational aidingof groups of aircraft, primarily intended for the fighter SAAB JAS 39 Gripen,as long as an aircraft gets GPS signals, it is easy to estimate position, but theGPS is relatively easy to jam, rendering alternative methods of positioning necessary.To use internal sensors measuring accelerations and angular velocities is agood replacement on short terms, but gives a drift in positioning over longer timeperiods. To resolve these issues, we review different possibilities to improve navigation performance bycombining measurement data from different aircraft using a consensus filter.We show that the performance canbe improved by using measurements of distance and angles to other aircraft withinthe group in a distributed filter.The filter is implemented in Matlab and evaluated in different scenarios, and this Extended Kalman-Consensus Filter (EKCF) is compared to a previously proposed solution using an Extended Kalman Filter (EKF). / Det här examensarbetet vidareutvecklar en befintlig algorithm för navigeringsstöttningav grupper av flygplan, främst inriktat på SAAB JAS 39 Gripen. Genomatt kombinera mätdata från olika flygplan kommer vi gå igenom hur man kanförbättra prestanda genom applicering av consensusfilter. Så länge ett plan harGPS-signal är positionering enkelt. Dock är den relativt lätt att störa ut, vilketgör alternativa lösningar för positionering nödvändiga. Att använda interna sensorersom mäter accelerationer och vinkelhastigheter fungerar utmärkt på kortsikt, men ger en drift över en längre tidsperiod.För att lösa de här problemen utvärderar vi olika möjligheter att förbättra navigationsprestandangenom att kombinera mätdata från olika flygplan med hjälpav ett consensusfilter. Vi visar att prestandan kan förbättras genom att användadistans- och vinkelmätningar inom gruppen med distribuerade filter. Filtret ärimplementerat i Matlab med olika scenarier och jämför Extended Kalman-ConsensusFilter (EKCF) med den föregående lösningen med ett Extended Kalman Filter (EKF).
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Consensus Algorithms and Distributed Structure Estimation in Wireless Sensor NetworksJanuary 2017 (has links)
abstract: Distributed wireless sensor networks (WSNs) have attracted researchers recently due to their advantages such as low power consumption, scalability and robustness to link failures. In sensor networks with no fusion center, consensus is a process where
all the sensors in the network achieve global agreement using only local transmissions. In this dissertation, several consensus and consensus-based algorithms in WSNs are studied.
Firstly, a distributed consensus algorithm for estimating the maximum and minimum value of the initial measurements in a sensor network in the presence of communication noise is proposed. In the proposed algorithm, a soft-max approximation together with a non-linear average consensus algorithm is used. A design parameter controls the trade-off between the soft-max error and convergence speed. An analysis of this trade-off gives guidelines towards how to choose the design parameter for the max estimate. It is also shown that if some prior knowledge of the initial measurements is available, the consensus process can be accelerated.
Secondly, a distributed system size estimation algorithm is proposed. The proposed algorithm is based on distributed average consensus and L2 norm estimation. Different sources of error are explicitly discussed, and the distribution of the final estimate is derived. The CRBs for system size estimator with average and max consensus strategies are also considered, and different consensus based system size estimation approaches are compared.
Then, a consensus-based network center and radius estimation algorithm is described. The center localization problem is formulated as a convex optimization problem with a summation form by using soft-max approximation with exponential functions. Distributed optimization methods such as stochastic gradient descent and diffusion adaptation are used to estimate the center. Then, max consensus is used to compute the radius of the network area.
Finally, two average consensus based distributed estimation algorithms are introduced: distributed degree distribution estimation algorithm and algorithm for tracking the dynamics of the desired parameter. Simulation results for all proposed algorithms are provided. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2017
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Consensus control for multi-agent sytems with input delayWang, Chunyan January 2016 (has links)
This thesis applies predictor-based methods for the distributed consensus control of multi-agent systems with input delay. "Multi-agent systems" is a term used to describe a group of agents which are connected together to achieve specified control tasks over a communication network. In many applications, the subsystems or agents are required to reach an agreement upon certain quantities of interest, which is referred to as "consensus control". This input delay may represent delays in the network communication. The main contribution of this thesis is to provide feasible methods to deal with the consensus control for general multi-agent systems with input delay. The consensus control for general linear multi-agent systems with parameter uncertainties and input delay is first investigated under directed network connection. Artstein reduction method is applied to deal with the input delay. By transforming the Laplacian matrix into the real Jordan form, delay-dependent conditions are derived to guarantee the robust consensus control for uncertain multi-agent systems with input delay. Then, the results are extended to a class of Lipschitz nonlinear multi-agent systems and the impacts of Lipschitz nonlinearity and input delay in consensus control are investigated. By using tools from control theory and graph theory, sufficient conditions based on the Lipschitz constant are identified for proposed protocols to tackle the nonlinear terms in the system dynamics. Other than the time delay, external disturbances are inevitable in various practical systems including the multi-agent systems. The consensus disturbance rejection problems are investigated. For linear multi-agent systems with bounded external disturbances, Truncated Predictor Feedback (TPF) approach is applied to deal with the input delay and the H_infinity consensus analysis is put in the framework of Lyapunov analysis. Sufficient conditions are derived to guarantee the H_infinity consensus in time domain. Some disturbances in real engineering problems have inherent characteristics such as harmonics and unknown constant load. For those kinds of disturbances in Lipschitz nonlinear multi-agent systems with input delay, Disturbance Observer-Based Control (DOBC) technique is applied to design the disturbance observers. A new predictor-based control scheme is constructed for each agent by utilizing the estimate of the disturbance and the prediction of the relative state information. Sufficient delay-dependent conditions are derived to guarantee consensus with disturbance rejection.
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Fusion d'informations incertaines sans commensurabilité des échelles de référence / Incommensurable ranked belief bases mergingRossit, Julien 10 July 2009 (has links)
Le problème de fusion d’informations survient dès qu’il faut prendre en compte des bases de données distribuées, des systèmes multi-agents ou des informations distribuées en général. La plupart des approches de fusion proposées dans la littérature reposent sur des opérateurs d'agrégation : ceux-ci combinent les degrés de cohérence des différentes interprétations vis-à-vis des sources à fusionner, eux-même fortement dépendants des poids que ces sources accordent à leurs propres croyances. Mais lorsque les sources ne partagent pas une signification commune des poids qu'elles utilisent, quel sens cela a-t-il de comparer ou d'agréger ces mêmes poids ? Ainsi, nous étudions dans cette thèse différentes approches de fusion de croyances en l'absence de commensurabilité des échelles utilisées. Nous proposons tout d'abord une première méthode, reposant sur la notion d'échelle compatible, que nous appliquons à des opérateurs basés sur la somme et sur le maximum. Les opérateurs résultants peuvent être caractérisés au moyen d’un ensemble infini d’échelles compatibles, mais également au moyen de relations de type Pareto sur l’ensemble des mondes possibles. Puis nous étudions plus particulièrement certaines familles d’échelles compatibles afin de caractériser des opérateurs moins prudents et prenant en compte l'intensité des poids. Nous fournissons une analyse complète de la production des inférences et de la rationalité des opérateurs de fusion définis. En particulier, nous proposons la notion de consensus, souhaitable en l'absence de l'hypothèse de commensurabilité et vérifiée par la plupart de nos opérateurs. / The problem of merging multiple-source information is crucial for many applications, in particular when one requires to take into account several potentially conflicting pieces of information, such as distributed databases frameworks, multi-agent systems, or distributed information in general. The relevant pieces of information are provided by different sources and all existing pieces of information have to be confronted to obtain a global and coherent point of view. This problem is well-known as the data fusion problem. Most of existing merging methods are based on the following assumption: ranks associated with beliefs are commensurable from one source to another. This commensurability assumption can be too strong for several applications: comparing or combining ranks does not make sense if sources do not share the same meaning of scales. This thesis proposes different solutions to the problem of incommensurability for ranked beliefs merging. Our first main contribution consists of proposing a natural way to restore commensurability relying on the notion of compatible scales. The second one directly defines a partial pre-order between interpretations in a way similar to the one based on the Pareto criterion. Moreover, this thesis introduces several inference relations based on some selection functions of compatible scales. We analyze the impact of these selection functions on the satisfaction of rational postulates, and on the prudence of merging operators. In particular we introduce a stronger version of the fairness postulate, called the consensus postulate. We show that most of our defined merging operators constitute consensual approaches.
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Budování institucí v postkonfliktních oblastech: Pátrání po legitimních institucích v Kosovu / Institution Building in Post-Conflict Areas: The Quest for Legitimate Institutions in KosovoSemenov, Andrej January 2020 (has links)
The pivotal argument of this thesis is that, due to specific circumstances, Kosovo operates as an EU protectorate. Firstly, the political status of Kosovo deeply divides the UN members, including the major powers, which makes unilateral decisions ineffective. This implies that neither side can achieve maximalist demands, and thus further negotiations are required. Secondly, both representatives of Kosovo and Serbia expressed hope that their future is in the EU. Both sides are ready to compromise their legal and/or political status and welcome a solution under the formula: Kosovo to be independent of Serbia even if it means that Kosovo is not a sovereign state; and, Serbia not to recognise Kosovo, even if it means that Serbia loses authority over the region. Thirdly, the great powers, led by the USA and Russia, decided that the conflict and the political status of Kosovo should be facilitated by the EU. This decision, accompanied by the ICJ decision that Kosovo's solution should be sought through the EU political channels, gives the EU role of a moral agent. Finally, while the EU protects Kosovo in international affairs, it also requires from Serbia to recognise Kosovo's institutions and local autonomy.
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Learning Gene Regulatory Networks Computationally from Gene Expression Data Using Weighted ConsensusFujii, Chisato 16 April 2015 (has links)
Gene regulatory networks analyze the relationships between genes allowing us to un- derstand the gene regulatory interactions in systems biology. Gene expression data from the microarray experiments is used to obtain the gene regulatory networks. How- ever, the microarray data is discrete, noisy and non-linear which makes learning the networks a challenging problem and existing gene network inference methods do not give consistent results. Current state-of-the-art study uses the average-ranking-based consensus method to combine and average the ranked predictions from individual methods. However each individual method has an equal contribution to the consen- sus prediction. We have developed a linear programming-based consensus approach which uses learned weights from linear programming among individual methods such that the methods have di↵erent weights depending on their performance. Our result reveals that assigning di↵erent weights to individual methods rather than giving them equal weights improves the performance of the consensus. The linear programming- based consensus method is evaluated and it had the best performance on in silico and Saccharomyces cerevisiae networks, and the second best on the Escherichia coli network outperformed by Inferelator Pipeline method which gives inconsistent results across a wide range of microarray data sets.
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A Consensus Curriculum for Laboratory Management Training for Pathology ResidentsWeiss, Ronald L., McKenna, Barbara J., Lord-Toof, Melissa, Thompson, Nancie Noie, Datnow, Brian, Dysert, Peter A., Inamdar, Kedar V., Kaul, Karen L., Kirkley, Scott A., Mullersman, Jerald E., Roseff, Susan D., Stanton, Constance A., Stowell, Christopher P., Terrazas, Enrique, Zander, Dani S. 01 November 2011 (has links)
Through the combined efforts of the American Pathology Foundation (APF), the American Society for Clinical Pathology (ASCP), and the Program Directors Section (PRODS) of the Association of Pathology Chairs (APC), a needs assessment was performed via a survey on the PRODS listserv, workshops at the APC/PRODS annual meetings in 2009 and 2010, and a Work Group of representatives of APF, ASCP, and PRODS. Residency program needs and resource constraints common to training pathology residents in practice and laboratory management were identified. In addition, a consensus curriculum for management training was created to serve as a resource for residency training program directors and others. The curriculum was converted into a "wiki" design tool for use by program directors, residents, and faculty.
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Pressure Ulcers: Avoidable or Unavoidable? Results of the National Pressure Ulcer Advisory Panel Consensus ConferenceBlack, Joyce M., Edsberg, Laura E., Baharestani, Mona M., Langemo, Diane, Goldberg, Margaret, McNichol, Laurie, Cuddigan, Janet 01 February 2011 (has links)
Although pressure ulcer (PrU) development is now generally considered an indicator for quality of care, questions and concerns about situations in which they are unavoidable remain. Considering the importance of this issue and the lack of available research data, in 2010 the National Pressure Ulcer Advisory Panel (NPUAP) hosted a multidisciplinary conference to establish consensus on whether there are individuals in whom pressure ulcer development may be unavoidable and whether a difference exists between end-of-life skin changes and pressure ulcers. Thirty-four stakeholder organizations from various disciplines were identified and invited to send a voting representative. Of those, 24 accepted the invitation. Before the conference, existing literature was identified and shared via a webinar. A NPUAP task force developed standardized consensus questions for items with none or limited evidence and an interactive protocol was used to develop consensus among conference delegates and attendees. Consensus was established to be 80% agreement among conference delegates. Unanimous consensus was achieved for the following statements: most PrUs are avoidable; not all PrUs are avoidable; there are situations that render PrU development unavoidable, including hemodynamic instability that is worsened with physical movement and inability to maintain nutrition and hydration status and the presence of an advanced directive prohibiting artificial nutrition/hydration; pressure redistribution surfaces cannot replace turning and repositioning; and if enough pressure was removed from the external body the skin cannot always survive. Consensus was not obtained on the practicality or standard of turning patients every 2 hours nor on concerns surrounding the use of medical devices vis-à-vis their potential to cause skin damage. Research is needed to examine these issues, refine preventive practices in challenging situations, and identify the limits of prevention.
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The Legitimacy of Selected Watershed Organizations in the Midwestern United StatesHall, Bruce Martin 01 December 2013 (has links) (PDF)
Legitimacy in natural resource management refers to the degree to which citizens accept and comply with stated goals and policies. Lack of legitimacy can threaten collaborative-based watershed groups that rely on voluntary compliance to achieve their water quality goals. These groups are locally-based, and sprouted up due to the complexities and political barriers that have prevented better control of non-point, or diffuse, pollution off the landscape and into streams and lakes. One of the most cited requirements for legitimacy in natural resource collaborations is inclusive representation. An exploratory study of several watershed groups in Wisconsin and Illinois uncovered a worrisome exclusion of key stakeholders in the watershed along with an absence of certain demographic groups. Key underrepresented stakeholders included farmers, federal government officials, and national environmental groups. The absence of farmer participation is especially troubling considering the large amount of agricultural land contained within two of the basins studied. In addition, the voluntary nature of watershed group collaboration led to a stilted demographic base, with white males of higher income and education dominating the process. Public participation in watershed groups has been cited numerous times in the literature as a key ingredient of legitimacy, yet it seems that the citizens in the watershed rely on elected officials for their representation. Results from this survey uncovered a lack of participation by elected officials, however, and this provided another barrier to inclusive and high-quality representation in watershed organizations. Another common feature of watershed collaborations is consensus decision-making, but these consensus groups often exhibited exclusion of "difficult" stakeholders, as well as self-exclusion of people who lacked patience with the time-consuming nature of the process. Survey results also indicated that some people felt contentious issues were being avoided in an attempt to reach consensus, as was documented in the literature. Accountability was an identified as a threat to legitimacy in both the focus groups and surveys, and there were doubts about follow-through once projects were agreed upon. Umbrella organizations that provided capacity-building and scientific expertise would often switch to other funded projects, and some wondered if outcomes could be maintained. Government was often cited in the surveys and focus groups as an entity that can be used to foster accountability, but the same respondents seemed to detest more government regulation while embracing accountability. Overall, respondents seemed conflicted about the role of government in these collaborations. Lack of trust was found to be very intense in the two Wisconsin watersheds, due mostly to run-ins with the Department of Natural Resources (DNR). Lack of trust spurred participation in watershed groups, particularly, when property owners lived lakeside. Meetings would become crowed as landowners wary of regulation or restrictions on their property came to protect their turf. While lack of trust may encourage participation, it also reduces overall legitimacy in the three watersheds studied in this paper, and still appears to be a large stumbling block to legitimacy despite many years of effort. Scientific uncertainty regarding sources of pollutants added to distrust between municipalities in the Illinois watershed, and this was exacerbated by a paucity of monitoring stations and baseline data. The watershed groups studied in this paper were three of the most successful and long-standing collaborations in this region -- and benefitted from effective leadership, capacity-building at multiple scales, transparency, and quality representation. But even in these groups many red flags emerged to threaten legitimacy, and hence the long-term sustainability and success of such groups. More research is needed to test some of the ideas uncovered here, but relying on a voluntary-approach to deal with the insidious problem of non-point source pollution may be a recipe for disaster. Alternative management strategies must be developed to combat runoff pollution, and it seems that more regulation and strict benchmarks should be instituted at the local level --- and be nested within larger scales at the state, regional, and federal level. In this type of strategy the local government would provide the "sticks" with land-use controls and pollution fees, and the state could be a source of "carrots" in the way of funding for projects.
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Modification of Weight Bias: Examining the Effects of Social Influence on the Expession of Anti-Fat AttitudesHarper, Jessica C. 25 August 2009 (has links)
No description available.
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