Prohibited Volume Avoidance for Aircraft

This thesis describes the development of a pilot override control system that prevents aircraft entering critical regions of space, known as prohibited volumes. The aim is to prevent another 9/11 style terrorist attack, as well as act as a general safety system for transport aircraft. The thesis presents the design and implementation of three core modules in the system; the trajectory generation algorithm, the trigger mechanism for the pilot override and the trajectory following element. The trajectory generation algorithm uses a direct multiple shooting strategy to provide trajectories through online computation that avoid pre-defi ned prohibited volume exclusion regions, whilst accounting for the manoeuvring capabilities of the aircraft. The trigger mechanism incorporates the logic that decides the time at which it is suitable for the override to be activated, an important consideration for ensuring that the system is not overly restrictive for a pilot. A number of methods are introduced, and for safety purposes a composite trigger that incorporates di fferent strategies is recommended. Trajectory following is best achieved via a nonlinear guidance law. The guidance logic sends commands in pitch, roll and yaw to the control surfaces of the aircraft, in order to closely follow the generated avoidance trajectory. Testing and validation is performed using a full motion simulator, with volunteers flying a representative aircraft model and attempting to penetrate prohibited volumes. The proof-of-concept system is shown to work well, provided that extreme aircraft manoeuvres are prevented near the exclusion regions. These hard manoeuvring envelope constraints allow the trajectory following controllers to follow avoidance trajectories accurately from an initial state within the bounding set. In order to move the project closer to a commercial product, operator and regulator input is necessary, particularly due to the radical nature of the pilot override system

Measurement of acceleration while walking as an automated method for gait assessment in dairy cattle

The aims were to determine whether measures of acceleration of the legs and back of dairy cows while they walk could help detect changes in gait or locomotion associated with lameness and differences in the walking surface. In 2 experiments, 12 or 24 multiparous dairy cows were fitted with five 3-dimensional accelerometers, 1 attached to each leg and 1 to the back, and acceleration data were collected while cows walked in a straight line on concrete (experiment 1) or on both concrete and rubber (experiment 2). Cows were video-recorded while walking to assess overall gait, asymmetry of the steps, and walking speed. In experiment 1, cows were selected to maximize the range of gait scores, whereas no clinically lame cows were enrolled in experiment 2. For each accelerometer location, overall acceleration was calculated as the magnitude of the 3-dimensional acceleration vector and the variance of overall acceleration, as well as the asymmetry of variance of acceleration within the front and rear pair of legs. In experiment 1, the asymmetry of variance of acceleration in the front and rear legs was positively correlated with overall gait and the visually assessed asymmetry of the steps (r ≥0.6). Walking speed was negatively correlated with the asymmetry of variance of the rear legs (r=−0.8) and positively correlated with the acceleration and the variance of acceleration of each leg and back (r ≥0.7). In experiment 2, cows had lower gait scores [2.3 vs. 2.6; standard error of the difference (SED)=0.1, measured on a 5-point scale] and lower scores for asymmetry of the steps (18.0 vs. 23.1; SED=2.2, measured on a continuous 100-unit scale) when they walked on rubber compared with concrete, and their walking speed increased (1.28 vs. 1.22m/s; SED=0.02). The acceleration of the front (1.67 vs. 1.72g; SED=0.02) and rear (1.62 vs. 1.67g; SED=0.02) legs and the variance of acceleration of the rear legs (0.88 vs. 0.94g; SED=0.03) were lower when cows walked on rubber compared with concrete. Despite the improvements in gait score that occurred when cows walked on rubber, the asymmetry of variance of acceleration of the front leg was higher (15.2 vs. 10.4%; SED=2.0). The difference in walking speed between concrete and rubber correlated with the difference in the mean acceleration and the difference in the variance of acceleration of the legs and back (r ≥0.6). Three-dimensional accelerometers seem to be a promising tool for lameness detection on farm and to study walking surfaces, especially when attached to a leg.The aims were to determine whether measures of acceleration of the legs and back of dairy cows while they walk could help detect changes in gait or locomotion associated with lameness and differences in the walking surface. In 2 experiments, 12 or 24 multiparous dairy cows were fitted with five 3-dimensional accelerometers, 1 attached to each leg and 1 to the back, and acceleration data were collected while cows walked in a straight line on concrete (experiment 1) or on both concrete and rubber (experiment 2). Cows were video-recorded while walking to assess overall gait, asymmetry of the steps, and walking speed. In experiment 1, cows were selected to maximize the range of gait scores, whereas no clinically lame cows were enrolled in experiment 2. For each accelerometer location, overall acceleration was calculated as the magnitude of the 3-dimensional acceleration vector and the variance of overall acceleration, as well as the asymmetry of variance of acceleration within the front and rear pair of legs. In experiment 1, the asymmetry of variance of acceleration in the front and rear legs was positively correlated with overall gait and the visually assessed asymmetry of the steps (r ≥0.6). Walking speed was negatively correlated with the asymmetry of variance of the rear legs (r=−0.8) and positively correlated with the acceleration and the variance of acceleration of each leg and back (r ≥0.7). In experiment 2, cows had lower gait scores [2.3 vs. 2.6; standard error of the difference (SED)=0.1, measured on a 5-point scale] and lower scores for asymmetry of the steps (18.0 vs. 23.1; SED=2.2, measured on a continuous 100-unit scale) when they walked on rubber compared with concrete, and their walking speed increased (1.28 vs. 1.22m/s; SED=0.02). The acceleration of the front (1.67 vs. 1.72g; SED=0.02) and rear (1.62 vs. 1.67g; SED=0.02) legs and the variance of acceleration of the rear legs (0.88 vs. 0.94g; SED=0.03) were lower when cows walked on rubber compared with concrete. Despite the improvements in gait score that occurred when cows walked on rubber, the asymmetry of variance of acceleration of the front leg was higher (15.2 vs. 10.4%; SED=2.0). The difference in walking speed between concrete and rubber correlated with the difference in the mean acceleration and the difference in the variance of acceleration of the legs and back (r ≥0.6). Three-dimensional accelerometers seem to be a promising tool for lameness detection on farm and to study walking surfaces, especially when attached to a leg.Peer reviewe

Behavioral changes in dairy cows with mastitis

Mastitis is a frequent and painful disease in dairy cows. However, pain detection and alleviation in mastitic cows has been overlooked. The objectives of this study were to measure behavioral changes in dairy cows with clinical mastitis and to investigate the effect of intramammary infusion of an antibiotic on lying behavior and behavior during milking. In experiment 1, 42 lactating cows were used: 14 mastitic cows and 28 control cows. Mastitic and control cows were subjected to an evaluation of pain responses on d 1 (mastitis detection day), and 2, 3, and 7d after the last antibiotic treatment (d 10+). The antibiotic treatment was administered to mastitic cows twice a day, starting on d 1, for at least 3 consecutive days. Behavioral changes were evaluated by measuring lying behavior, reactivity during milking (stepping, lifting, and kicking), weight distribution, and hock-to-hock distance. Overall, mastitic cows spent less time lying down on d 2 compared with control cows. The percentage of time lying on the mastitic quarter side did not differ significantly between mastitic and control cows. No differences were observed between control and mastitic cows on the number of steps per 24h on each day. Restless behavior during milking did not differ between treatments. Restless behaviors differed significantly within mastitic cows between days. Frequency of kicks per minute was higher on d 1 compared with d 2, frequency of lifts was higher on d 1 and 2 compared with d 10+, and frequency of steps was higher on d 2 compared with d 10+. The variability of weight that mastitic cows applied to the leg on the mastitic quarter side was higher on d 1 than on d 10+. For control cows, the variability in weight applied to the homologous leg of the mastitic quarter side leg was higher on d 1 compared with d 2 and 3. The hock-to-hock distance did not differ between treatments. Mild clinical mastitis might not cause sufficient pain to observe marked changes in behaviors. However, cows showed differences in lying time and reactivity during milking and slight differences in the laterality of lying. To further develop methodologies for assessing pain in mastitic cows, it is worth applying the methodologies used in this study to cows with moderate to severe mastitis, followed by their validation using analgesic treatment, to ensure that any change is a pain-specific behavior rather than a simple reflex. In experiment 2, no effect of intramammary infusion of the antibiotic was observed on lying behavior or behavior during milking. Cows with mild clinical mastitis present behavioral changes in lying behavior and at milking time, which could be associated with discomfort

Effects of sand and straw bedding on the lying behavior, cleanliness, and hoof and hock injuries of dairy cows

"This experiment compared the effects of sand and straw bedding in free stalls on resting time, cleanliness, hock injuries, and hoof health of dairy cows and tested whether cow preferences for a bedding material depended on the familiarity with the material. A total of 52 dairy cows were kept either on straw bedded concrete stalls or sand stalls for at least 21 wk. The lying behavior was observed, and hock lesions, hoof health, and cleanliness of the cows and stalls were measured. A 5-d preference test between sand and straw stalls was conducted at the end of the experiment. The total daily duration of lying was longer for cows on straw bedding than on sand bedding (straw 749 +/- 16 vs. sand 678 +/- 19 min). During the preference test, cows that had been kept on straw bedding preferred lying in straw stalls [straw 218.7 (133.4 to 239.7) vs. sand 9.0 min (2.8 to 44.8)]; however, cows that had been kept on sand showed no preference [straw 101.3 (51.7 to 205.9) vs. sand 94.3 min (54.1 to 156.1, median and interquartile range)]. Although there were no differences in the dirtiness of stalls, the cows using straw stalls were dirtier than cows using sand stalls [straw 6.04 (5.39 to 6.28) vs. sand 4.19 (3.62 to 5.16)]. At the end of experiment the severity of hock lesions was lower for cows on sand than for cows on straw [sand 0.5 (0.0 to 1.0) vs. straw 1.0 (1.0 to 2.0)]. The improvement in overall hoof health over the observation period was greater for cows kept on sand compared with cows kept on straw [sand -2.00 (-3.75 to -0.25) vs. straw 0.00 (-2.00 to 2.00)]. Straw bedding increased the time that cows spend lying, and cows preferred straw stalls to sand stalls. However, previous experience with sand reduces avoidance of sand stalls. Sand stalls were advantageous for cow cleanliness and health; hock lesions and claw diseases healed more quickly for cows using sand stalls compared with straw.""This experiment compared the effects of sand and straw bedding in free stalls on resting time, cleanliness, hock injuries, and hoof health of dairy cows and tested whether cow preferences for a bedding material depended on the familiarity with the material. A total of 52 dairy cows were kept either on straw bedded concrete stalls or sand stalls for at least 21 wk. The lying behavior was observed, and hock lesions, hoof health, and cleanliness of the cows and stalls were measured. A 5-d preference test between sand and straw stalls was conducted at the end of the experiment. The total daily duration of lying was longer for cows on straw bedding than on sand bedding (straw 749 +/- 16 vs. sand 678 +/- 19 min). During the preference test, cows that had been kept on straw bedding preferred lying in straw stalls [straw 218.7 (133.4 to 239.7) vs. sand 9.0 min (2.8 to 44.8)]; however, cows that had been kept on sand showed no preference [straw 101.3 (51.7 to 205.9) vs. sand 94.3 min (54.1 to 156.1, median and interquartile range)]. Although there were no differences in the dirtiness of stalls, the cows using straw stalls were dirtier than cows using sand stalls [straw 6.04 (5.39 to 6.28) vs. sand 4.19 (3.62 to 5.16)]. At the end of experiment the severity of hock lesions was lower for cows on sand than for cows on straw [sand 0.5 (0.0 to 1.0) vs. straw 1.0 (1.0 to 2.0)]. The improvement in overall hoof health over the observation period was greater for cows kept on sand compared with cows kept on straw [sand -2.00 (-3.75 to -0.25) vs. straw 0.00 (-2.00 to 2.00)]. Straw bedding increased the time that cows spend lying, and cows preferred straw stalls to sand stalls. However, previous experience with sand reduces avoidance of sand stalls. Sand stalls were advantageous for cow cleanliness and health; hock lesions and claw diseases healed more quickly for cows using sand stalls compared with straw.""This experiment compared the effects of sand and straw bedding in free stalls on resting time, cleanliness, hock injuries, and hoof health of dairy cows and tested whether cow preferences for a bedding material depended on the familiarity with the material. A total of 52 dairy cows were kept either on straw bedded concrete stalls or sand stalls for at least 21 wk. The lying behavior was observed, and hock lesions, hoof health, and cleanliness of the cows and stalls were measured. A 5-d preference test between sand and straw stalls was conducted at the end of the experiment. The total daily duration of lying was longer for cows on straw bedding than on sand bedding (straw 749 +/- 16 vs. sand 678 +/- 19 min). During the preference test, cows that had been kept on straw bedding preferred lying in straw stalls [straw 218.7 (133.4 to 239.7) vs. sand 9.0 min (2.8 to 44.8)]; however, cows that had been kept on sand showed no preference [straw 101.3 (51.7 to 205.9) vs. sand 94.3 min (54.1 to 156.1, median and interquartile range)]. Although there were no differences in the dirtiness of stalls, the cows using straw stalls were dirtier than cows using sand stalls [straw 6.04 (5.39 to 6.28) vs. sand 4.19 (3.62 to 5.16)]. At the end of experiment the severity of hock lesions was lower for cows on sand than for cows on straw [sand 0.5 (0.0 to 1.0) vs. straw 1.0 (1.0 to 2.0)]. The improvement in overall hoof health over the observation period was greater for cows kept on sand compared with cows kept on straw [sand -2.00 (-3.75 to -0.25) vs. straw 0.00 (-2.00 to 2.00)]. Straw bedding increased the time that cows spend lying, and cows preferred straw stalls to sand stalls. However, previous experience with sand reduces avoidance of sand stalls. Sand stalls were advantageous for cow cleanliness and health; hock lesions and claw diseases healed more quickly for cows using sand stalls compared with straw."Peer reviewe

Colostrum Intake by Newborn Piglets

Colostrum intake by newborn piglets was studied by weighing piglets every 10 min for their first 1-4 h with the sow, and their cumulative weight increases were used as estimates of colostrum intake. In seven litters, four piglets were monitored for 4 h beginning about 2 h after the birth of the first piglet in order to determine if colostrum is available continuously or released in discrete ejections. There was little synchrony between litter-mates in their intake in the first hour, but by the second hour of monitoring (starting about 3 h after farrowing began), much of the colostrum was released in discrete ejections and piglets achieved most of their intake during the few 10-min intervals when an ejection occurred. To examine the effect of birth sequence, four piglets were added to the udder each hour for 3 consecutive hours. Piglets added in the last hour showed a small but significant tendency (P \u3c 0.05) to obtain less colostrum than those added in the middle of the sequence. In nine litters, three piglets were confined to posterior and three to anterior teats for 1.5 h to examine the effect of teat position. Those on posterior teats had slightly but significantly (P = 0.02) lower estimated intake than piglets on anterior teats. Although low-birth-weight piglets, late-born piglets, and piglets sucking only posterior teats tended to obtain less colostrum, the differences were small, and most piglets obtained an amount of colostrum consistent with normal serum immunoglobulin concentratio

Nutritive and Nonnutritive Sucking and the Temporal Organization of the Suckling Behavior of Domestic Piglets

Detailed video recordings of the suckling behavior of one piglet from each of four litters were analyzed to determine how the components of piglet suckling behavior are organized in relation to the time of milk ejection and the temporal pattern of grunting by the sow. Early in the suckling episode, most piglets massaged the udder with their snouts, and then changed gradually to sucking the teats with slow mouth movements (1-2/sec). The piglets then had a distinct phase of sucking with rapid mouth movements (4-5/sec) which began suddenly and lasted about 5 to 15 sec. The weight gains of piglets removed at different times, showed that piglets consumed milk during the fast sucking but not during the preceding slow sucking, regardless of how much slow sucking had occurred. Three of the four sows showed a characteristic increase in rate of grunting about 20 to 25 sec before fast sucking began. The piglets\u27 change from massaging to slow sucking often coincided with the increase in grunt rate, but the timing of the transition varied greatly. This suggests that the change in grunting is one but not the only cue used by the piglets to time their suckling behavior. During the slow, nonnutritive sucking, mouth movements were highly variable in duration, with occasional short bursts of rapid mouth movements. This contrasted with the more uniform duration of fast sucking movements. Evidently, in piglets, nutritive and nonnutritive sucking differ in both rate and temporal patterning

Effect of floor type on the performance, physiological and behavioural responses of finishing beef steers

peer-reviewedBackground:The study objective was to investigate the effect of bare concrete slats (Control), two types of mats [(Easyfix mats (mat 1) and Irish Custom Extruder mats (mat 2)] fitted on top of concrete slats, and wood-chip to simulate deep bedding (wood-chip placed on top of a plastic membrane overlying the concrete slats) on performance, physiological and behavioral responses of finishing beef steers. One-hundred and forty-four finishing steers (503 kg; standard deviation 51.8 kg) were randomly assigned according to their breed (124 Continental cross and 20 Holstein–Friesian) and body weight to one of four treatments for 148 days. All steers were subjected to the same weighing, blood sampling (jugular venipuncture), dirt and hoof scoring pre study (day 0) and on days 23, 45, 65, 86, 107, 128 and 148 of the study. Cameras were fitted over each pen for 72 h recording over five periods and subsequent 10 min sampling scans were analysed. Results: Live weight gain and carcass characteristics were similar among treatments. The number of lesions on the hooves of the animals was greater (P < 0.05) on mats 1 and 2 and wood-chip treatments compared with the animals on the slats. Dirt scores were similar for the mat and slat treatments while the wood-chip treatment had greater dirt scores. Animals housed on either slats or wood-chip had similar lying times. The percent of animals lying was greater for animals housed on mat 1 and mat 2 compared with those housed on concrete slats and wood chips. Physiological variables showed no significant difference among treatments. Conclusions: In this exploratory study, the performance or welfare of steers was not adversely affected by slats, differing mat types or wood-chip as underfoot material

Boredom-like states in mink and their behavioural correlates: a replicate study

Scientists and laypeople have long expressed concern that animals in non-enriched, unchanging environments might experience boredom. However, this had attracted little empirical study: the state is difficult to assess without verbal self-reports, and spontaneous behavioural signs of boredom can vary in humans, making it hard to identify signs likely to be valid in other species. We operationally define boredom as a negative state that causes an increased, generalised interest in diverse stimuli. Previously, we demonstrated that this state existed in mink housed in non-enriched cages, compared to those in preferred, stress-reducing enriched enclosures; and that this heightened interest in stimuli positively correlated with time spent lying still but awake, while negatively correlating with locomotor stereotypic behaviour. However, these results needed replication. The current study tested for the same effects, in a new cohort of 20 male mink, by presenting 11 stimuli ranging from those predicted to typically be aversive (e.g. predator cues) to those predicted to be rewarding (e.g. food rewards; moving objects to chase). Where housing treatments differed, non-enriched mink were again more interested in the stimuli presented, spending longer oriented towards and in contact with them (e.g. for aversive stimuli: F1,9=6.27, p=0.034 and F1,9=8.24, p=0.019, respectively). Lying still but awake again correlated with interest in the stimuli (shorter latencies to contact rewarding stimuli: F1,17=3.70, p=0.036; in enriched mink only, more time oriented to and in contact with all stimuli: F1,8=9.49, p=0.015 and F1,8=15.9, p=0.004). In contrast, the previous correlations with stereotypic behaviour were not replicated. We therefore conclude that mink housed in non-enriched cages likely experience boredom-like states, and that time spent lying still while awake could potentially be used as a cage-side indicator of these states. We also suggest how future researchers might address further fundamental and practical questions about animal boredom, in mink and other species

Lift and drag characteristics of flexible pitching and heaving wings

There is a pressing need for Micro Air Vehicles (MAV) that are light, powerful, and efficient to perform military reconnaissance missions and search and rescue operations. These MAVs have length scales on the order of 10 cm, where traditional steady flight wing designs perform poorly. An alternative flight mechanism is the unsteady flapping employed by birds, bees, and insects. This unsteady motion has been shown to be more effective in generating lift and reducing drag forces. Current research into unsteady flapping flight has been primarily focused on the translational heaving and rotational pitching motion of rigid wings. The purpose of this research is to investigate how the kinematics of flapping wings of variable trailing edge flexibility affect flight performance as measured by lift and drag. To investigate this a custom built motion apparatus was used to pitch and heave the wings over a range of conditions. The forces on these wings were measured with a pair of load cells attached to the base of the pitching and heaving device that capture the axial and normal loads on the wing. The effect of changing the non-dimensional heaving amplitude, non-dimensionalized by the chord length, was found by changing the amplitude of the translational heaving motion. Similarly, the pitching amplitude was tested over a range of conditions from non-pitching to pitching with an amplitude of 20 degrees. The central angle that the wing pitched about was advanced from -20 degrees to 20 degrees to explore the role of average angle in unsteady flapping flight. The frequency of the pitching and heaving motion was increased from 0.25 Hz to 0.625 Hz. The major findings from this research are that the Lift/Drag ratio increased with an increase in pitching amplitudes for all flexibilities. The moderately flexible wing performed best for all central angles, with the peak lift occurring when the central angle was at its maximum. The Lift/Drag ratio peaked for a central angle of zero, as the drag was at its minimum. Increasing the heaving amplitude caused slight decreases in lift and drag forces. The reduced frequency decreased the lift and the drag slightly. For all trials the effect of flexibility was small compared to the effect of kinematics

Measures of weight distribution of dairy cows to detect lameness and the presence of hoof lesions

There is increasing interest in automated methods of detecting lame cows. Hoof lesion data and measures of weight distribution from 61 lactating cows were examined in this study. Lame cows were identified with different numerical rating scores (NRS) used as thresholds (NRS \u3e3 and NRS ≥3.5) for lameness. The ratio of weight applied to a pair of legs (LWR) when the cow was standing was calculated using a special weigh scale, and the cows were gait scored using a 1 to 5 NRS. Hoof lesions were scored and the cows placed into 1 of 4 mutually exclusive categories of hoof lesion: a) no lesions, b) moderate or severe hemorrhages, c) digital dermatitis, and d) sole ulcers. Regression analysis and receiver operating characteristic (ROC) curves were used to analyze the relation between hoof lesions and LWR. A clear relationship was found between NRS and LWR for the cows with sole ulcers (R2 = 0.79). The LWR could differentiate cows with sole ulcers from sound cows with no hoof lesions [area under the curve (AUC) = 0.87] and lame cows from nonlame cows with lameness thresholds NRS \u3e3 (AUC = 0.71) and NRS ≥3.5 (AUC = 0.88). There was no relationship between LWR and NRS for cows with digital dermatitis. Measurement of how cows distribute their weight when standing holds promise as a method of automated detection of lameness