Network Structure and Design in the Deregulated U.S. Airline Industry: an Argument for Re-Regulation?

This paper develops a model to explain and analyze the evolution of network structure (connectivity)and design (flight frequency, aircraft size, prices) in the post-deregulation U.S. airline industry. We show that legacy carriers choice of Hub-and-Spoke networks and the emergence of low cost carriers (LCCs) operating Point-to-Point networks were optimal choices. We demonstrate that LCCs need not necessarily charge lower prices, and their entry impacted legacy carriers’ prices in all markets, even those where there is no direct competition. We show that in response to entry, legacy carriers optimally lower flight frequency, leading to longer wait times between flights for which passengers are compensated by lower prices; conversely, if the entrant later exits, legacy carriers raise flight frequency and therefore prices, which may erroneously appear to be predatory pricing when in fact it is the consequence of optimal network redesign. Finally, we demonstrate that even though low cost carriers lower prices, total social welfare with competing network structures can also be lowered. In other words, the poor financial performance of legacy carriers is not due to their inefficiency per se but due to an efficient Hub-and-Spoke network undermined by competition from inefficient Point-to-Point networks. We argue that social welfare may have been, and still can be, higher if entry and exit in air passenger travel industry is regulated.Networks, Airlines, Regulation

Parliament Square and cultural balance of power in Britain

It seems that the debate on Cecil Rhodes’ legacy in particular and the legacy left by the British Empire in former colonies in general, has now come to an end; the University of Oxford has very recently declared that the statue will remain (The Guardian 2016). The fiery debate, initiated by Oxford students in the “Rhodes Must Fall” campaign has attracted a great deal of popular attention. Public figures as different as Naomi Wolf and Harry Mount have rallied together to plea against the statue’s removal, accusing the students of “suppressing free speech” and of having a “hypersensitive” and “unsophisticated” attitude to the world (Wolf 2016; Mount 2016)

Competitive multi-agent search

textWhile evolutionary computation is well suited for automatic discovery in engineering, it can also be used to gain insight into how humans and organizations could perform more effectively. Using a real-world problem of innovation search in organizations as the motivating example, this dissertation formalizes human creative problem solving as competitive multi-agent search. It differs from existing single-agent and team-search problems in that the agents interact through knowledge of other agents' searches and through the dynamic changes in the search landscape caused by these searches. The main hypothesis is that evolutionary computation can be used to discover effective strategies for competitive multi-agent search. This hypothesis is verified in experiments using an abstract domain based on the NK model, i.e. partially correlated and tunably rugged fitness landscapes, and a concrete domain in the form of a social innovation game. In both domains, different specialized strategies are evolved for each different competitive environment, and also strategies that generalize across environments. Strategies evolved in the abstract domain are more effective and more complex than hand-designed strategies and one based on traditional tree search. Using a novel spherical visualization of the fitness landscapes of the abstract domain, insight is gained about how successful strategies work, e.g. by tracking positive changes in the landscape. In the concrete game domain, human players were modeled using backpropagation, and used as opponents to create environments for evolution. Evolved strategies scored significantly higher than the human models by using a different proportion of actions, providing insights into how performance could be improved in social innovation domains. The work thus provides a possible framework for studying various human creative activities as competitive multi-agent search in the future.Computer Science

Antonius C. G. M. Robben and Alexander Laban Hinton, 2023, Perpetrators Encountering Humanity’s Dark Side

In Perpetrators Encountering Humanity’s Dark Side, two veteran anthropologists provide the discipline with a set of practical lessons for conducting fieldwork with interlocutors who have participated in mass atrocities. These lessons are based on the “practical wisdom” – what the authors also term as phronesis by borrowing from ancient Greek (p. 5) - that they have developed through their decades of research in Argentina and Cambodia, where two politically different kinds of authoritarian regimes unleashed programmes of mass violence on their populations in the 1970s. The book begins with a desire to address “anthropology’s lack of methodological reflection on encounters with perpetrators of mass violence in the field,” but is far more than a methods guide. The book is in part ethnographic self-analysis and in part a Socratic dialogue involving the authors. It begins with theoretical reflections on what perpetration means (Introduction), and continues to examine the problems that ethnographers face when conducting research with agents of violence (Part I including Chapters 1 and 2), the marks that these violent interlocutors leave on the researchers (Part II including Chapters 3 and 4), and the problem of ethnographically writing about difficult and violent subjects (Part III including Chapters 5 and 6). Each part is introduced by interludes which set out the themes examined in the subsequent chapters

Unsettled crossings: underpass journeys in an English town

What kinds of ‘sensory configurations’ (Thomas, 2010), and moral orders, are created in places that are simultaneously formed and rendered marginal by infrastructures of hegemonic automobility? In this paper, we explore this question with reference to one micro-site we have encountered in our current study of security and everyday life in an English town – Macclesfield in Cheshire. That site is the Gas Road underpass, a key pedestrian route between the town centre and the east of the town on the other side of its busiest road. Underpasses are generic urban artefacts, mundane features of necessity, of light and darkness, of entry and exit, of solitude and transient encounter. This residual place is for many users one to be passed through, often quite quickly, without particular engagement. It is, on the other hand, also a regular gathering point for the homeless and young people, and a focus for intervention by local authorities, responding to concerns about public drinking and other undesired activities. The underpass provokes concerned talk among residents about the safety of those who (have to) use it, and unsettled debate among local decision-makers over how to beautify, illuminate, regulate, or otherwise improve it. In the paper, we use film, photographs, interviews and in situ observation, to explore the contested ways in which this place is sensed. We argue for a situated understanding of how this residual space unsettles the town’s sense of place, and for acknowledgment of how history and landscape shape the local meanings of such places and journeys

Robotic contour tracking with adaptive feedforward control by fuzzy online tuning

Industrial robots have great importance in manufacturing. Typical uses of the robots are welding, painting, deburring, grinding, polishing and shape recovery. Most of these tasks such as grinding, deburring need force control to achieve high performance. These tasks involve contour following. Contour following is a challenging task because in many of applications the geometry physical of the targeted contour are unknown. In addition to that, achieving tasks as polishing, grinding and deburring requires small force and velocity tracking errors. In order to accomplish these tasks, disturbances have to be taken account. In this thesis the aim is to achieve contour tracking with using fuzzy online tuning. The fuzzy method is proposed in this thesis to adjust a feedforward force control parameter. In this technique, the varying feedforward control parameter compensates for disturbance effects. The method employs the chattering of control signal and the normal force and tangential velocity errors to adjust the control term. Simulations with the model of a direct drive planar elbow manipulator are used to last proposed technique

Evaluation of the Injury Experiences of Healthcare Worker and the Measures taken, in a Training and Research Hospital

Aim: Healthcare workers frequently carry out invasive procedures as part of their jobs. Regarding this situation, they are at risk for stab injuries and also for infectious diseases such as primarily hepatitis infections and Immune Deficiency Syndrome (HIV) depending on the contact of blood and body fluids to mucous membranes. Applying the infection control measures effectively is very important to reduce the risk of transmission. In this study, it was aimed to evaluate the occupational injuries in our hospital and to ensure the relevant measures by determining whether the necessary precautions were taken. Mehtod: Healthcare workers injuries which were occurred at Recep Tayyip Erdoğan University Education and Research Hospital between 2016 and 2018 were investigated retrospectively. After the records of the infection control committee were examined retrospectively in the first two years, the rate of injury was found to be high, once a month, by the Infectious Diseases Specialist, Medical Microbiology Specialist and Infection Control Committee. Face-to-face training seminars were given to reduce the changes in the data in the last three months of 2018, when the training was given. Results: A total of 220 healthcare workers were included in our study in 3 years. The average age of the workers was 26.4 ± 4.1 years, and the female / male ratio was found as 143/77. In all three years, injuries were seen most commonly in nurses, second in intern students. After the trainings, the greatest reduction in the injury rates was observed in injectör needle sting injuries. Among the hospital staff, the greatest decrease in the injuries was observed in the cleaning staff Conclusion: Healthcare workers should be followed up that whether or not take protective measures such as primarly active and passive immune prophylaxis and carry out infection control measures correctly and effectively, against the occupationally transmitted diseases. Feedback should be received for this purpose and in case of deficiencies, it should be ensured to raise awareness by regular and continuous trainings.Keywords: Education, awareness, healtcare injuryDOI: 10.7176/JHMN/75-0

A reconfigurable antenna with beam steering and beamwidth variability for wireless communications

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.A reconfigurable antenna (RA) capable of steering its beam into the hemisphere corresponding to ¿ ¿ {-40°,0°,40°}, Ø ¿ {0°,45°,90°,-45°}, and of changing 3-dB beamwidth, where ¿3dB ¿ (40°,100°), Ø ¿ {45°,90°,-45°} for broadside direction is presented. The RA operating in 5 GHz band consists of a driven patch antenna with a parasitic layer placed above it. The upper surface of the parasitic layer has two pixelated metallic strips, where each strip has four pixels. The pixels connected via PIN diode switches enable to change the current distribution on the antenna providing the desired modes of operation. A prototype RA was characterized indicating an average gain of 8 dB. Measured and simulated impedance and radiation patterns agreed well. The proposed RA offers an efficient solution by using less number of switches compared to other RAs. The system level simulations for a 5G orthogonal frequency division multiple access system show that the RA improves capacity/coverage trade-off significantly, where the RA modes and users are jointly determined to create proper beamwidth and directivity at the access point antennas. For a hotspot scenario, the presented RA provided 29% coverage and 16% capacity gain concurrently.Peer ReviewedPostprint (author's final draft

CalibFPA: A Focal Plane Array Imaging System based on Online Deep-Learning Calibration

Compressive focal plane arrays (FPA) enable cost-effective high-resolution (HR) imaging by acquisition of several multiplexed measurements on a low-resolution (LR) sensor. Multiplexed encoding of the visual scene is typically performed via electronically controllable spatial light modulators (SLM). An HR image is then reconstructed from the encoded measurements by solving an inverse problem that involves the forward model of the imaging system. To capture system non-idealities such as optical aberrations, a mainstream approach is to conduct an offline calibration scan to measure the system response for a point source at each spatial location on the imaging grid. However, it is challenging to run calibration scans when using structured SLMs as they cannot encode individual grid locations. In this study, we propose a novel compressive FPA system based on online deep-learning calibration of multiplexed LR measurements (CalibFPA). We introduce a piezo-stage that locomotes a pre-printed fixed coded aperture. A deep neural network is then leveraged to correct for the influences of system non-idealities in multiplexed measurements without the need for offline calibration scans. Finally, a deep plug-and-play algorithm is used to reconstruct images from corrected measurements. On simulated and experimental datasets, we demonstrate that CalibFPA outperforms state-of-the-art compressive FPA methods. We also report analyses to validate the design elements in CalibFPA and assess computational complexity