Acquisition of control information in a wind shear

When an aircraft encounters a change of air mass it may experience a change in horizontal wind sufficient to cause appreciable change in airspeed and, therefore, in lift. It may also suffer a change in vertical wind and, therefore, in vertical speed. The adverse combination of these effects may result in a significant excursion below the correct vertical profile and this may be especially serious if it happens during the latter part of an approach. Appropriate action should then be taken very quickly to avoid a situation from which the aircraft can scarcely recover, implying that suitable information needs to be readily accessible to the pilot. The purpose of this paper is to explore circumstances in which it is difficult to meet this requirement in conventionally equipped aircraft, because of time factors affecting the flow of information

Head-up display in the non-precision approach

The problem of head-up guidance for an aircraft making an instrument approach without glide slope information is discussed. Requirements for path control are considered for each section of the approach profile and a head-up display is developed to meet these needs. The display is an unreferenced flight director which is modified by adding a ground referenced symbol as an alternative guidance component. The director is used for holding altitude in the first segment and for descent at a controlled rate in the second segment. It is used in the third segment to maintain the minimum decision altitude while assessing the approach situation. This is done by means of occasional brief changes to the referenced symbol. In the final segment a visual approach is made with the referenced symbol used continuously for path control. The display is investigated experimentally in simulated approaches made by three pilots. The results show a fair agreement between objective and subjective estimates of the quality of landing decisions

An experimental evaluation of head-up display formats

Three types of head-up display format are investigated. Type 1 is an unreferenced (conventional) flight director, type 2 is a ground referenced flight path display, and type 3 is a ground referenced director. Formats are generated by computer and presented by reflecting collimation against a simulated forward view in flight. Pilots, holding commercial licenses, fly approaches in the instrument flight mode and in a combined instrument and visual flight mode. The approaches are in wind shear with varied conditions of visibility, offset, and turbulence. The displays are equivalent in pure tracking but there is a slight advantage for the unreferenced director in poor conditions. Flight path displays are better for tracking in the combined flight mode, possibly because of poor director control laws and the division of attention between superimposed fields. Workloads is better for the type 2 displays. The flight path and referenced director displays are criticized for effects of symbol motion and field limiting. In the subjective judgment of pilots familiar with the director displays, they are rated clearly better than path displays, with a preference for the unreferenced director. There is a fair division of attention between superimposed fields

Algorithmic Debugging of Real-World Haskell Programs: Deriving Dependencies from the Cost Centre Stack

Existing algorithmic debuggers for Haskell require a transformation of all modules in a program, even libraries that the user does not want to debug and which may use language features not supported by the debugger. This is a pity, because a promising ap- proach to debugging is therefore not applicable to many real-world programs. We use the cost centre stack from the Glasgow Haskell Compiler profiling environment together with runtime value observations as provided by the Haskell Object Observation Debugger (HOOD) to collect enough information for algorithmic debugging. Program annotations are in suspected modules only. With this technique algorithmic debugging is applicable to a much larger set of Haskell programs. This demonstrates that for functional languages in general a simple stack trace extension is useful to support tasks such as profiling and debugging

A pearl on SAT solving in Prolog

A succinct SAT solver is presented that exploits the control provided by delay declarations to implement watched literals and unit propagation. Despite its brevity the solver is surprisingly powerful and its elegant use of Prolog constructs is presented as a programming pearl

A conformal head-up display for the visual approach

The degree of conformity used in matching a superimposed display to its visual background is considered in relation to the information available for vertical guidance and control during a purely visual approach. The information may be represented by individual symbols or combined in a single symbol, and the relative merits of these methods are discussed. A fully conformal display format is developed for the purpose of showing both the position and direction of the flight path, with provision for the effects of disturbances, ILS compatibility, and control needs. The field of view needed for all conditions and phases of the visual approach with a fully conformal display is studied in relation to the limitations of conventional collimator systems. Methods are discussed which depend on deviation of the sight line, and on windshield reflection of the uncollimated image of a simple pointer. Limited flight tests show some promise for the uncollimated method

Independent component analysis (ICA) applied to dynamic oxygen-enhanced MRI (OE-MRI) for robust functional lung imaging at 3 T.

PURPOSE: Dynamic lung oxygen-enhanced MRI (OE-MRI) is challenging due to the presence of confounding signals and poor signal-to-noise ratio, particularly at 3 T. We have created a robust pipeline utilizing independent component analysis (ICA) to automatically extract the oxygen-induced signal change from confounding factors to improve the accuracy and sensitivity of lung OE-MRI. METHODS: Dynamic OE-MRI was performed on healthy participants using a dual-echo multi-slice spoiled gradient echo sequence at 3 T and cyclical gas delivery. ICA was applied to each echo within a thoracic mask. The ICA component relating to the oxygen-enhancement signal was automatically identified using correlation analysis. The oxygen-enhancement component was reconstructed, and the percentage signal enhancement (PSE) was calculated. The lung PSE of current smokers was compared with nonsmokers; scan-rescan repeatability, ICA pipeline repeatability, and reproducibility between two vendors were assessed. RESULTS: ICA successfully extracted a consistent oxygen-enhancement component for all participants. Lung tissue and oxygenated blood displayed the opposite oxygen-induced signal enhancements. A significant difference in PSE was observed between the lungs of current smokers and nonsmokers. The scan-rescan repeatability and the ICA pipeline repeatability were good. CONCLUSION: The developed pipeline demonstrated sensitivity to the signal enhancements of the lung tissue and oxygenated blood at 3 T. The difference in lung PSE between current smokers and nonsmokers indicates a likely sensitivity to lung function alterations that may be seen in mild pathology, supporting future use of our methods in patient studies

Compositional Explanation of Types and Algorithmic Debugging of Type Errors

The type systems of most typed functional programming languages are based on the Hindley-Milner type system. A practical problem with these type systems is that it is often hard to understand why a program is not type correct or a function does not have the intended type. We suggest that at the core of this problem is the difficulty of explaining why a given expression has a certain type. The type system is not defined compositionally. We propose to explain types using a variant of the Hindley-Milner type system that defines a compositional type explanation graph of principal typings. We describe how the programmer understands types by interactive navigation through the explanation graph. Furthermore, the explanation graph can be the foundation for algorithmic debugging of type errors, that is, semi-automatic localisation of the source of a type error without even having to understand the type inference steps. We implemented a prototype of a tool to explore the usefulness of the proposed methods

The formation and function of the neutrophil phagosome.

Neutrophils are the most abundant circulating leukocyte and are crucial to the initial innate immune response to infection. One of their key pathogen-eliminating mechanisms is phagocytosis, the process of particle engulfment into a vacuole-like structure called the phagosome. The antimicrobial activity of the phagocytic process results from a collaboration of multiple systems and mechanisms within this organelle, where a complex interplay of ion fluxes, pH, reactive oxygen species, and antimicrobial proteins creates a dynamic antimicrobial environment. This complexity, combined with the difficulties of studying neutrophils ex vivo, has led to gaps in our knowledge of how the neutrophil phagosome optimizes pathogen killing. In particular, controversy has arisen regarding the relative contribution and integration of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-derived antimicrobial agents and granule-delivered antimicrobial proteins. Clinical syndromes arising from dysfunction in these systems in humans allow useful insight into these mechanisms, but their redundancy and synergy add to the complexity. In this article, we review the current knowledge regarding the formation and function of the neutrophil phagosome, examine new insights into the phagosomal environment that have been permitted by technological advances in recent years, and discuss aspects of the phagocytic process that are still under debate

Improving system of distribution local railway junction in cars

Проведено аналіз перспективних напрямків удосконалення технології розвезення місцевих вагонів у залізничному вузлі. Виконано огляд наукових праць вітчизняних та зарубіжних вчених, що займаються тематикою вдосконалення та ефективного нормування передавального руху, оптимізації взаємодії та підвищення ефективності функціонування залізничних станцій у вузлах. В роботі поставлено завдання оптимізації розвозу місцевих вагонів у розвиненому залізничному вузлі. Складена залежність для визначення сумарного часу знаходження місцевого вагону у вузлі. Удосконалено математичну модель, алгоритм якої, незалежно від складності, конфігурації, кореспонденції та інших місцевих умов розвинених вузлів, дозволяє визначити оптимальне місце концентрації технічної роботи з місцевими вагонами відповідно до обраних параметрів та критеріїв оцінки.Проведен анализ перспективных направлений усовершенствования технологии развоза местных вагонов в железнодорожном узле. Выполнен обзор научных трудов отечественных и зарубежных ученых, которые занимаются тематикой совершенствования и эффективного нормирования передаточного движения, оптимизации взаимодействия и повышения эффективности функционирования железнодорожных станций в узлах. В работе поставлено задание оптимизации розвоза местных вагонов в развитом железнодорожном узле. Составленная зависимость для определения суммарного времени нахождения местного вагона в узле. Усовершенствована математическая модель, алгоритм которой, независимо от сложности, конфигурации, корреспонденции и других местных условий развитых узлов, позволяет определить оптимальное место концентрации технической работы с местными вагонами в соответствии с избранными параметрами и критериями оценки.The analysis promising areas of improvement technologies deliver a local carriages railway junction. A survey scientific works domestic and foreign scientists involved subjects Streamlining and standardization of gear movement, optimizing interaction and improve the efficiency railway stations in knots. In this paper, the task optimization local commercial cars in developed railway junction. Compiled dependence to determine the total time spent in the local car site. Improved mathematical model, an algorithm which, regardless of complexity, configuration, correspondence and other local conditions developed nodes to determine optimum concentration technical work with local cars according to selected parameters and benchmarks. Analysis local circulation vahonopotoku showed that most time the car is idle for trucks and industrial plants. Given the above, it can be argued that the current development industry and research necessary technologies of local coaches in major junctions