5,019 research outputs found

    Progress on Intelligent Guidance and Control for Wind Shear Encounter

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    Low altitude wind shear poses a serious threat to air safety. Avoiding severe wind shear challenges the ability of flight crews, as it involves assessing risk from uncertain evidence. A computerized intelligent cockpit aid can increase flight crew awareness of wind shear, improving avoidance decisions. The primary functions of a cockpit advisory expert system for wind shear avoidance are discussed. Also introduced are computational techniques being implemented to enable these primary functions

    An expert system for wind shear avoidance

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    A study of intelligent guidance and control concepts for protecting against the adverse effects of wind shear during aircraft takeoffs and landings is being conducted, with current emphasis on developing an expert system for wind shear avoidance. Principal objectives are to develop methods for assessing the likelihood of wind shear encounter (based on real-time information in the cockpit), for deciding what flight path to pursue (e.g., takeoff abort, landing go-around, or normal climbout or glide slope), and for using the aircraft's full potential for combating wind shear. This study requires the definition of both deterministic and statistical techniques for fusing internal and external information , for making go/no-go decisions, and for generating commands to the manually controlled flight. The program has begun with the development of the WindShear Safety Advisor, an expert system for pilot aiding that is based on the FAA Windshear Training Aid; a two-volume manual that presents an overview , pilot guide, training program, and substantiating data provides guidelines for this initial development. The WindShear Safety Advisor expert system currently contains over 200 rules and is coded in the LISP programming language

    Systematic innovation and the underlying principles behind TRIZ and TOC

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    Innovative developments in the design of product and manufacturing systems are often marked by simplicity, at least in retrospect, that has previously been shrouded by restrictive mental models or limited knowledge transfer. These innovative developments are often associated with the breaking of long established trade-off compromises, as in the paradigm shift associated with JIT & TQM, or the resolution of design contradictions, as in the case of the dual cyclone vacuum cleaner. The rate of change in technology and the commercial environment suggests the opportunity for innovative developments is accelerating, but what systematic support is there to guide this innovation process. This paper brings together two parallel, but independent theories on inventive problem solving; one in mechanical engineering, namely the Russian Theory of Inventive Problem Solving (TRIZ) and the other originating in manufacturing management as the Theory of Constraints (TOC). The term systematic innovation is used to describe the use of common underlying principles within these two approaches. The paper focuses on the significance of trade-off contradictions to innovation in these two fields and explores their relationship with manufacturing strategy development

    Learning from the experts: exploring playground experience and activities using a write and draw technique.

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    BACKGROUND: Qualitative research into the effect of school recess on children's physical activity is currently limited. This study used a write and draw technique to explore children's perceptions of physical activity opportunities during recess. METHODS: 299 children age 7-11 years from 3 primary schools were enlisted. Children were grouped into Years 3 & 4 and Years 5 & 6 and completed a write and draw task focusing on likes and dislikes. Pen profiles were used to analyze the data. RESULTS: Results indicated 'likes' focused on play, positive social interaction, and games across both age groups but showed an increasing dominance of games with an appreciation for being outdoors with age. 'Dislikes' focused on dysfunctional interactions linked with bullying, membership, equipment, and conflict for playground space. Football was a dominant feature across both age groups and 'likes/dislikes' that caused conflict and dominated the physically active games undertaken. CONCLUSION: Recess was important for the development of conflict management and social skills and contributed to physical activity engagement. The findings contradict suggestions that time spent in recess should be reduced because of behavioral issues

    New concept in brazing metallic honeycomb panels

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    Aluminum oxide coating provides surface which will not be wetted by brazing alloy and which stops metallic diffusion welding of tooling materials to part being produced. This method eliminates loss of tooling materials and parts from braze wetting and allows fall-apart disassembly of tooling after brazing

    Bessel beam propagation: Energy localization and velocity

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    The propagation of a Bessel beam (or Bessel-X wave) is analyzed on the basis of a vectorial treatment. The electric and magnetic fields are obtained by considering a realistic situation able to generate that kind of scalar field. Specifically, we analyze the field due to a ring-shaped aperture over a metallic screen on which a linearly polarized plane wave impinges. On this basis, and in the far field approximation, we can obtain information about the propagation of energy flux and the velocity of the energy.Comment: 6 pages, 4 figure

    Leadership in Groups: Social Networks and Perceptions of Formal and Informal Leaders

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    The labors of organizational and behavioral science researchers have resulted in a literature robust in the study of leadership and social networks. Empirical examination of both topics has shown significant organizational outcomes, but breadth is lacking both within and between the disciplines. Studies of leadership have seen the preponderance of the effort focused on formal leaders, while most social network studies examine only one informal structure. Moreover, there exists a paucity of studies, which have sought to examine the interrelationships between leadership and social networks. In an effort to address these voids, this thesis investigated: 1) The concurrent existence of multiple social networks, 2) How leaders, both formal and informal, are positioned within the networks, 3) How leader positions in the network change over time, 4) How network positioning affects group members\u27 perceptions of formal leader performance, and 5) How a member\u27s position in the network relates to peer selection as an informal leader. The Expressive-Instrumental Leadership Model, based on behavioral science theory and past empirical studies, was proposed as a means of investigation. A population of 431 military students and instructors was surveyed seven times over a period of eight weeks to gather longitudinally-based social networks data. Additionally, both instructors and students were peer-rated on their leadership performance. The results were statistically analyzed and compared to outcomes predicted by the model. The results showed partial support for the proposed model as three of six hypotheses were supported. Partial support was found for remaining hypotheses, with unique environmental factors possible impacting study results. The author proposed further study of the model to gain additional insight

    A Geographic Information System Assessment Method for Fire Management: Identifying Fire Danger Areas

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    In partnership with the USDA Forest Service and the Utah Division of Forestry, Fire, and State Lands, a geographic information system (GIS) was used to create a wildland fire assessment methodology. GIS layers (or themes) include topography, infrastructure, vegetation, climate, sensitive natural values, and fire history. Two phases of assessment are presented: a preliminary analysis designed for planning use at the landscape level, and a detailed analysis for site-specific use. Results of the phase 1 assessment are density grids delineating areas of high fire occurrence and suggesting to managers where a phase 2 assessment is needed. By using the environmental, human, and topographic information listed earlier, probability maps of wildland fire occurrence were developed with a GIS and multiple logistic regression. In both cases, high fire danger areas can be overlaid with protection areas (natural or human-made value areas) to identify critical fire danger areas. Because GIS is commonly used in land management, it facilitates the sharing and updating of geographic information between resource professionals of different agencies and organizations. Local officials will be able to use GIS spatial and tabular data for planning, zoning, and fire ordinance development. Land management specialists can locate, prioritize, and target high and critical fire danger areas for presuppression mitigation efforts such as prescribed fires, defensible-space projects, and fire-break construction (e.g., greenbelts, parkways). Furthermore, GIS assessment layers can be manipulated and exported to create the required raster GIS data themes for FARSITE (a fire growth simulator). Fire managers will be able to spatially predict fire spread, intensity, and behavior under complex topographic and climatic conditions. This method, combined with the expertise of fire specialists, offers an improved and cost-effective assessment technique for wildland fire management
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