Robustness and Adaptiveness Analysis of Future Fleets

Making decisions about the structure of a future military fleet is a challenging task. Several issues need to be considered such as the existence of multiple competing objectives and the complexity of the operating environment. A particular challenge is posed by the various types of uncertainty that the future might hold. It is uncertain what future events might be encountered; how fleet design decisions will influence and shape the future; and how present and future decision makers will act based on available information, their personal biases regarding the importance of different objectives, and their economic preferences. In order to assist strategic decision-making, an analysis of future fleet options needs to account for conditions in which these different classes of uncertainty are exposed. It is important to understand what assumptions a particular fleet is robust to, what the fleet can readily adapt to, and what conditions present clear risks to the fleet. We call this the analysis of a fleet's strategic positioning. This paper introduces how strategic positioning can be evaluated using computer simulations. Our main aim is to introduce a framework for capturing information that can be useful to a decision maker and for defining the concepts of robustness and adaptiveness in the context of future fleet design. We demonstrate our conceptual framework using simulation studies of an air transportation fleet. We capture uncertainty by employing an explorative scenario-based approach. Each scenario represents a sampling of different future conditions, different model assumptions, and different economic preferences. Proposed changes to a fleet are then analysed based on their influence on the fleet's robustness, adaptiveness, and risk to different scenarios

Dispersion-cancelled imaging with chirped laser pulses

This thesis deals with chirped-pulse interferometry, an interferometric imaging technique with a resolution which is unaffected by the normally detrimental effects of sample dispersion. The thesis begins with some important background definitions and concepts. The properties of ultrafast laser pulses are discussed, and the nonlinear process of sum-frequency generation is defined. Three different interferometric imaging systems introduced, namely optical coherence tomography, quantum optical coherence tomography, and chirped-pulse interferometry. Understanding the first two techniques is key to realizing the benefits provided by the third. In the first experiment a chirped-pulse interferometer is used to image the cells of an onion. This is the first time that a dispersion-cancelled technique has been used to image the interior structure of a biological sample. Laser pulses centred on 810 nm with 90 nm full-width at half-maximum bandwidth are chirped with a spatial light modulator in a 4f-system to create a superposition of frequency-anticorrelated pulses. The chirped pulses are sent into a cross-correlator with a sample of onion in one arm. The cellular structure of the onion is imaged to a depth of 0.5 mm with a resolution of 3.2 ± 0.6 μm. The introduction of 132 fs² of quadratic dispersion in front of the sample does not affect the resolution of the image. A three-dimensional image of the sample's internal structure is created. The second experiment uses a nonlinear chirping function to produce a narrower interference signal in a chirped-pulse interferometer than that given by linearly-chirped pulses; this competes with the inherently narrower signal seen in quantum optical coherence tomography systems. The nonlinear chirping function theoretically narrows the interference signal by 30%, matching the width of the quantum signal. Experimentally, a narrowing of 17% was observed. The nonlinear chirping function was shown to cancel the 132 fs² of unbalanced quadratic dispersion as effectively as the linear function. One of the main sources of background noise in a chirped-pulse interferometer is a narrow-band component of sum-frequency generated light from the interferometer's intense reference beam. This background is at the same frequency and has the same bandwidth as the signal. A third experiment is proposed in which the light in the sample and reference arms of the interferometer is chirped independently. If the light in both arms is a superposition of frequency-anticorrelated pulses with different average frequencies the interferometer should still be dispersion-cancelling, but the narrowband background will shift spectrally from the signal

Robustness and Adaptability Analysis of Future Military Air Transportation Fleets

Making decisions about the structure of a future military fleet is challenging. Several issues need to be considered, including multiple competing objectives and the complexity of the operating environment. A particular challenge is posed by the various types of uncertainty that the future holds. It is uncertain what future events might be encountered and how fleet design decisions will influence these events. In order to assist strategic decision-making, an analysis of future fleet options needs to account for conditions in which these different uncertainties are exposed. It is important to understand what assumptions a particular fleet is robust to, what the fleet can readily adapt to, and what conditions present risks to the fleet. We call this the analysis of a fleet’s strategic positioning. Our main aim is to introduce a framework that captures information useful to a decision maker and defines the concepts of robustness and adaptability in the context of future fleet design. We demonstrate our conceptual framework by simulating an air transportation fleet problem. We account for uncertainty by employing an explorative scenario-based approach. Each scenario represents a sampling of different future conditions and different model assumptions. Proposed changes to a fleet are then analysed based on their influence on the fleet’s robustness, adaptability, and risk to different scenarios

Testing classical and quantum theory with single photons

To date, quantum theory is the most successful physical theory that has been discovered. However, there is still the possibility that an inconsistency between experimental observations and the predictions of quantum theory may one day be found, thus prompting the replacement of quantum theory with a superior, post-quantum theory. To narrow down the scope of possibilities for the true theory that describes nature, one can perform experiments that falsify other physical theories, by demonstrating an incompatibility between experimental observations and the predictions of these theories. This thesis details two such experiments. First we provide relevant background information, beginning with a review of experimental quantum optics. Next, we review noncontextual ontological theories and discuss requirements for experimental tests of such theories. Finally, we discuss the framework of generalised probabilistic theories before introducing the two experiments. The first experiment is a test of noncontextual ontological (or hidden-variable) models of nature. An ontological model of a physical theory is one in which systems have preexisting properties, and a noncontextual ontological model is one in which systems that are indistinguishable experimentally are represented identically in the model. Physical theories that cannot be represented by a noncontextual ontological model are said to be nonclassical; quantum theory is an example of such a physical theory that is nonclassical in this sense. Prior to this thesis, experimental tests of the assumption of noncontextuality had assumed that the experiments were free of both systematic and statistical errors, which is not justifiable for any experiment. We introduce new analytical techniques that allow us to avoid making these assumptions, and perform an experiment with single photons that, with high confidence, rules out the possibility of describing nature with a noncontextual ontological model. The second experiment is a demonstration of self-consistent state and measurement tomography in the framework of generalised probabilistic theories (GPTs). The GPT framework is a very general, operationally-motivated framework for describing a physical theory in terms of the observable events predicted by the theory. We develop a technique for inferring the GPT description of a set of states and measurements directly from experimental data. By analysing our data in this general framework, we are able to test various candidate physical theories of nature. We perform an experiment with single photons, and quantify the size of possible variations between quantum theory and the true physical theory that describes nature

Americar Dreams (An Introduction)

Even though Baudrillard’s catchy piece of advice as for the most effective method of exploring America’s landscapes (both real and imaginary) comes from his postmodernist travelogue limited to its titular country, it is probably difficult for anyone interested in contemporary car cultures not to extend Baudrillard’s praise of the driving experience and perceive it in cognitive rather than transportation terms, not necessarily bounded by national borders. True, American driving culture and all its related contexts—its remarkable history, its contribution to social mobility, its spectacular cars, its mythologies, the list goes on and on—is not only the oldest one historically, but—given its ties with American life-styles, politics, social stratification and the overall consumerist mindset—also the most extreme one. From Henry Ford’s Model T storming millions of American households at the beginning of the 20th century to Elon Musk’s Tesla Roadster shot into space in the second decade of the following one, cars have shaped American horizons, both private and collective, like no other machine. This introductory text presents the concept of the present issue of RIAS as well as the concepts underlying its feature texts

Impact of Decmedetomidine on Opioid and Benzodiazepine Dosing Requirements in Children.

Poster presented at: Annual Update on Pediatric Cardiovascular Disease; February 2008; Scottsdale Arizona