5,006 research outputs found
An on-board near-optimal climb-dash energy management
On-board real time flight control is studied in order to develop algorithms which are simple enough to be used in practice, for a variety of missions involving three dimensional flight. The intercept mission in symmetric flight is emphasized. Extensive computation is required on the ground prior to the mission but the ensuing on-board exploitation is extremely simple. The scheme takes advantage of the boundary layer structure common in singular perturbations, arising with the multiple time scales appropriate to aircraft dynamics. Energy modelling of aircraft is used as the starting point for the analysis. In the symmetric case, a nominal path is generated which fairs into the dash or cruise state. Feedback coefficients are found as functions of the remaining energy to go (dash energy less current energy) along the nominal path
Climb-dash real-time calculations
On-board rear-optimal climb-dash energy management, optimal symmetric flight with an intermediate vehicle model, and energy states are presented
Social Workers\u27 Perceptions of Family Preservation Programs
The passage of the Adoptions and Safe Families Act of 1997, with its focus on child safety and concurrent planning, has presented family preservation workers with new challenges and new opportunities. Twenty volunteers from a large comprehensive social service agency were interviewed to determine their experiences with two models of family preservation—Multisystemic Therapy (MST) and Traditional Family Preservation Service (TFPS) or practice as usual. Workers from both programs were able to articulate values consistent with family preservation as important strengths of the programs— keeping families together and empowering families for example. Information from referring agencies was described as variable and not especially useful when working with seriously troubled families, especially as it related to risk and child safety. Both groups indicated that the jargon of family preservation had permeated their agencies, and that working with other agencies was at times a challenge, though for different reasons. Finally, despite some reservations about the effectiveness of short-term treatment with families that face serious challenges, both groups of workers were generally satisfied with family preservation as an approach to practice
Whale by-products for pig feeding
Pig feeding experiments at Denmark Research Station and Muresk Agricultural College in 1951 and 1952, were designed to investigate the value of whalemeal and whale solubles in comparison with meatmeal as protein supplements to a crushed wheat ration. Large quantities of whale solubles are available and, used efficiently, could greatly reduce the present shortage of protein supplements
Biometric evidence that sexual selection has shaped the hominin face.
We consider sex differences in human facial morphology in the context of developmental change. We show that at puberty, the height of the upper face, between the lip and the brow, develops differently in males and females, and that these differences are not explicable in terms of sex differences in body size. We find the same dimorphism in the faces of human ancestors. We propose that the relative shortening in men and lengthening in women of the anterior upper face at puberty is the mechanistic consequence of extreme maxillary rotation during ontogeny. A link between this developmental model and sexual dimorphism is made for the first time, and provides a new set of morphological criteria to sex human crania. This finding has important implications for the role of sexual selection in the evolution of anthropoid faces and for theories of human facial attractiveness
Optimal symmetric flight studies
Several topics in optimal symmetric flight of airbreathing vehicles are examined. In one study, an approximation scheme designed for onboard real-time energy management of climb-dash is developed and calculations for a high-performance aircraft presented. In another, a vehicle model intermediate in complexity between energy and point-mass models is explored and some quirks in optimal flight characteristics peculiar to the model uncovered. In yet another study, energy-modelling procedures are re-examined with a view to stretching the range of validity of zeroth-order approximation by special choice of state variables. In a final study, time-fuel tradeoffs in cruise-dash are examined for the consequences of nonconvexities appearing in the classical steady cruise-dash model. Two appendices provide retrospective looks at two early publications on energy modelling and related optimal control theory
2-An Archaeological Survey of Allegan County, Michigan: 1977 Transect Survey in the Lower Kalamazoo River Valley
Western Michigan University has sponsored archaeological field work in the Kalamazoo River Valley for the last 10 years. For the most part this research has been carried out by the Department of Anthropology\u27s archaeological field school, which has been located in the lower valley during all or portions of 6 field seasons: 1968, 1969, 1973, 1976, 1977 and 1978. Prior to 1976, the Department\u27s field program was directed by Elizabeth Baldwin Garland; and since that time by Garland and William Cremin.
With the inception of the Kalamazoo Basin Archaeological Project in 1976, the research objectives of our program in this universe have necessitated that we initiate systematic site survey as a means of acquiring data which could be used to delineate and explain prehistoric land use patterns. To collect these data, the first in a series of cross-valley transect surveys was conducted in the Hacklander site environs as part of the 1976 field school (Figure 1). On this occasion the survey was supported entirely out of the field school budget. Since then our survey program has been funded by National Register grants obtained through the Michigan History Division, Michigan Department of State
The influence of soccer match play on physiological and physical performance measures in soccer referees and assistant referees
Boundary spanning in the context of stakeholder engagement in collaborative water management
Boundary spanners are individuals able to reach across organizational borders to build relationships and interconnections to help better manage complex problems. What is not clear, however, are the skills that allow boundary spanners to cross diverse scales, sectors, and organizations. To address this gap, we use a qualitative case study approach to examine evidence for how boundary spanning skills are implemented in the context of stakeholder engagement for addressing water challenges in agricultural settings. We employ a hybrid deductive-inductive thematic analysis approach to examine interview data collected with 25 stakeholder participants as well as direct observation of engagement behavior. Interview instruments were designed to elicit responses related to six deductively derived skills of boundary spanning: relationship builder, authentic leadership, trustworthiness, autonomy, perspective-taking, and effective science communication. Our inductive analysis identified evidence for three additional boundary spanning skills. Our study finds that some boundary spanning skills were exhibited more than others, and their frequency of use varied throughout the engagement process, and certain skills were used interchangeably. This research provides guidance on what boundary spanning looks like in action, and thus provides guidance on identifying and enhancing these skills in stakeholder engagement for water resource management
Reduction in Physical Match Performance at the Start of the Second Half in Elite Soccer
Purpose: Soccer referees' physical match performances at the start of the second half (46-60 min) were evaluated in relation to both the corresponding phase of the first half (0-15 min) and players' performances during the same match periods. Methods: Match analysis data were collected (Prozone, UK) from 12 soccer referees on 152 English Premier League matches during the 2008/09 soccer season. Physical match performance categories for referees and players were total distance, high-speed running distance (speed >5.5 m/s), and sprinting distance (>7.0 m/s). The referees' heart rate was recorded from the start of their warm-up to the end of the match. The referees' average distances (in meters) from the ball and fouls were also calculated. Results: No substantial differences were observed in duration (16:42 ± 2:35 vs 16:27 ± 1:00 min) or intensity (107 ± 11 vs 106 ± 14 beats/ min) of the referees' preparation periods immediately before each half. Physical match performance was reduced during the initial phase of the second half when compared with the first half in both referees (effect sizes-standardized mean differences-0.19 to 0.73) and players (effect sizes 0.20 to 1.01). The degree of the decreased performance was consistent between referees and players for total distance (4.7 m), high-speed running (1.5 m), and sprinting (1.1 m). The referees were closer to the ball (effect size 0.52) during the opening phase the second half. Conclusion: Given the similarity in the referees' preparation periods, it may be that the reduced physical match performances observed in soccer referees during the opening stages of the second half are a consequence of a slower tempo of play
- …