Multi-Objective and Multidisciplinary Design Optimisation of Unmanned Aerial Vehicle Systems using Hierarchical Asynchronous Parallel Multi-Objective Evolutionary Algorithms

The overall objective of this research was to realise the practical application of Hierarchical Asynchronous Parallel Evolutionary Algorithms for Multi-objective and Multidisciplinary Design Optimisation (MDO) of UAV Systems using high fidelity analysis tools. The research looked at the assumed aerodynamics and structures of two production UAV wings and attempted to optimise these wings in isolation to the rest of the vehicle. The project was sponsored by the Asian Office of the Air Force Office of Scientific Research under contract number AOARD-044078. The two vehicles wings which were optimised were based upon assumptions made on the Northrop Grumman Global Hawk (GH), a High Altitude Long Endurance (HALE) vehicle, and the General Atomics Altair (Altair), Medium Altitude Long Endurance (MALE) vehicle. The optimisations for both vehicles were performed at cruise altitude with MTOW minus 5% fuel and a 2.5g load case. The GH was assumed to use NASA LRN 1015 aerofoil at the root, crank and tip locations with five spars and ten ribs. The Altair was assumed to use the NACA4415 aerofoil at all three locations with two internal spars and ten ribs. Both models used a parabolic variation of spar, rib and wing skin thickness as a function of span, and in the case of the wing skin thickness, also chord. The work was carried out by integrating the current University of Sydney designed Evolutionary Optimiser (HAPMOEA) with Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) tools. The variable values computed by HAPMOEA were subjected to structural and aerodynamic analysis. The aerodynamic analysis computed the pressure loads using a Boeing developed Morino class panel method code named PANAIR. These aerodynamic results were coupled to a FEA code, MSC.Nastran® and the strain and displacement of the wings computed. The fitness of each wing was computed from the outputs of each program. In total, 48 design variables were defined to describe both the structural and aerodynamic properties of the wings subject to several constraints. These variables allowed for the alteration of the three aerofoil sections describing the root, crank and tip sections. They also described the internal structure of the wings allowing for variable flexibility within the wing box structure. These design variables were manipulated by the optimiser such that two fitness functions were minimised. The fitness functions were the overall mass of the simulated wing box structure and the inverse of the lift to drag ratio. Furthermore, six penalty functions were added to further penalise genetically inferior wings and force the optimiser to not pass on their genetic material. The results indicate that given the initial assumptions made on all the aerodynamic and structural properties of the HALE and MALE wings, a reduction in mass and drag is possible through the use of the HAPMOEA code. The code was terminated after 300 evaluations of each hierarchical level due to plateau effects. These evolutionary optimisation results could be further refined through a gradient based optimiser if required. Even though a reduced number of evaluations were performed, weight and drag reductions of between 10 and 20 percent were easy to achieve and indicate that the wings of both vehicles can be optimised

Analyse effectiviteit van het akkervogelbeheer in Provincie Groningen : Evaluatierapport

De Werkgroep Grauwe Kiekendief en zijn oprichter Ben Koks zijn belangrijke pioniers geweest in het agrarische natuurbeheer. In de loop van de jaren hebben zij – in samenwerking met verschillende universiteiten – onafhankelijk, degelijk en vooral kritisch onderzoek geëntameerd, waarbij niet al van te voren vaststond dat genomen maatregelen wel zouden werken. Dit rapport vat veel van dit belangrijke werk same

Migrating Montagu's harriers frequently interrupt daily flights in both Europe and Africa

Time budgets are a powerful but hitherto seldom used way to study how migrants organise their bi‐annual travels. We studied daily time budgets of travelling Montagu's harriers Circus pygargus, based on GPS tracking data, in which we were particularly interested in how time budgets differ between regions and seasons, and are affected by wind. We found that Montagu's harriers used a relatively broad daily time window for travelling by starting daily travels just after sunrise and ending daily travels just before sunset. Occasionally, flights were extended into the night. Montagu's harriers frequently interrupted their daily flights for on average 1.5 h d–1. These interruptions occurred in all regions and seasons. The tracking data during interruptions suggested two different behaviours: in 41% of all interruptions the birds were moving (presumed foraging,) and in 32% they were stationary (presumed resting; the remaining interruptions could not be classified). The interruptions for foraging indicate that Montagu's harriers have a fly‐and‐forage migration strategy (i.e. combine travelling and foraging on the same day), but the interruptions for resting illustrate that their travels comprise of more than fly‐and‐forage behaviour alone. The large number of interruptions for foraging in the Sahara Desert indicates that this region is less hostile for a migrating raptor than presumed previously. Importantly, harriers spent more time on interruptions for resting on days with stronger headwinds, suggesting that interruptions for resting serve a function of waiting for more favourable weather conditions. Daily variation in time budgets was largely explained by wind; harriers flew more hours per day, and interrupted their flights fewer hours per day, on days they experienced stronger tailwinds. In contrast, time budgets were similar between regions and seasons, suggesting that wind rather than landscape and season shape travel routines of Montagu's harriers

Akkerrandenbeheer niet de sleutel tot succes voor de Veldleeuwerik in Oost-Groningen

De Veldleeuwerik, ooit een van de meest verbreide en talrijkste vogels van het boerenland, holt in aantallen achteruit. We staan er bij en kijken er naar, want goed broedbiologisch onderzoek naar de achteruitgang van de Veldleeuwerik in Nederland is schaars, laat staan pogingen om de achteruitgang te keren. Een uitzondering hierop is het langdurige veldleeuwerikenonderzoek in Oost- Groningen. Naast monitoring en onderzoek wordt hier ook agrarisch natuurbeheer getest. Akkerranden, stukjes extensieve ruigte die intensief boerenland omzomen, lijken de succesformule voor bijvoorbeeld de Grauwe Kiekendief te zijn, maar is deze maatregel ook het ei van Columbus voor de Veldleeuwerik

Collision risk of Montagu's Harriers Circus pygargus with wind turbines derived from high-resolution GPS tracking

Flight behaviour characteristics such as flight altitude and avoidance behaviour determine the species‐specific collision risk of birds with wind turbines. However, traditional observational methods exhibit limited positional accuracy. High‐resolution GPS telemetry represents a promising method to overcome this drawback. In this study, we used three‐dimensional GPS tracking data including high‐accuracy tracks recorded at 3‐s intervals to investigate the collision risk of breeding male Montagu's Harriers Circus pygargus in the Dutch–German border region. Avoidance of wind turbines was quantified by a novel approach comparing observed flights to a null model of random flight behaviour. On average, Montagu's Harriers spent as much as 8.2 h per day in flight. Most flights were at low altitude, with only 7.1% within the average rotor height range (RHR; 45–125 m). Montagu's Harriers showed significant avoidance behaviour, approaching turbines less often than expected, particularly when flying within the RHR (avoidance rate of 93.5%). For the present state, with wind farms situated on the fringes of the regional nesting range, collision risk models based on our new insights on flight behaviour indicated 0.6–2.0 yearly collisions of adult males (as compared with a population size of c. 40 pairs). However, the erection of a new wind farm inside the core breeding area could markedly increase mortality (up to 9.7 yearly collisions). If repowering of the wind farms was carried out using low‐reaching modern turbines (RHR 36–150 m), mortality would more than double, whereas it would stay approximately constant if higher turbines (RHR 86–200 m) were used. Our study demonstrates the great potential of high‐resolution GPS tracking for collision risk assessments. The resulting information on collision‐related flight behaviour allows for performing detailed scenario analyses on wind farm siting and turbine design, in contrast to current environmental assessment practices. With regard to Montagu's Harriers, we conclude that although the deployment of higher wind turbines represents an opportunity to reduce collision risk for this species, precluding wind energy developments in core breeding areas remains the most important mitigation measure

Eerste resultaten van het jaarrond volgen van Blauwe Kiekendieven broedend in het Oost-Groningse akkerland

Blauwe Kiekendieven zien we tegenwoordig vaker in de winter dan in de zomer. Het gaat uitermate slecht met de Nederlandse broedvogels en als er niets gebeurt zullen we de soort binnen afzienbare tijd als broedvogel verliezen. De voormalige bolwerken op de Waddeneilanden zijn zo goed als verlaten. Een hoopvolle ontwikkeling vormt de vestiging van de Blauwe Kiekendief in het Oost- Groningse akkerbouwgebied. In 2012-2013 werden drie van deze broedvogels uitgerust met UvA-BiTS GPS-loggers. A small breeding population (3-5 pairs) of Hen Harriers recently established in the east of the province of Groningen, the Netherlands, in large scale arable farmland. We equipped three adults, two males and one female, with UvA-BiTS GPS loggers to study home ranges and habitat use throughout the year (Fig. 1). One breeding male could be tracked during two subsequent summers (late nestling phase in 2012, prebreeding and incubation phase in 2013 (Fig. 2)). Although he nested in the same area, he used different home ranges in these subsequent years (overlap only 21%). Habitat use was similar between years. Most time was spent in (winter) cereals (60%) and grassland (22%), two crops that dominate in the study area (availability is 42 and 24%, respectively). Moreover, set-aside habitats, which are especially created and managed for breeding harriers, were preferred (4% used, 1% available). One breeding pair was tracked after their nest failed (Fig. 4). These non-breeding birds occupied much smaller summer home ranges. In addition, they used set-aside habitat much more intensively (up to 22%), until the start of the cereal harvest when they switched to using cereal stubbles. During the summer the female made three subsequent trips to Northwest Germany (Fig. 3). One male spent the winter in Spain, in an agricultural area near Olivenza (Fig. 6). Autumn and spring migration took 98 and 14 days, including 81 and 1 stopover days, respectively. The other individuals (one male and one female) spent the winter near the breeding area (Fig. 5). Loggers could not record positions during mid-winter as solar panels could not keep the batteries charged. Habitat use in winter was dominated by grassland (62%). Set-aside was also preferred (5%). The female made an 8-day mid-winter excursion to a nearby wetland area (Weerribben, Fig. 5)

Field margins as foraging habitat for skylarks (Alauda arvensis) in the breeding season

Agri-environment schemes have been established in many European countries to counteract the ongoing decline of farmland birds. In this study, the selection of foraging habitat by breeding skylarks was examined in relation to agri-environmental management on Dutch farmland. Field margin use was quantified and, based on the observed flight distances, the appropriateness of the current spatial arrangement of field margins in the study landscape was evaluated. Skylarks preferred field margins for foraging over all other habitat types relative to their surface area within the territories. The visiting rate of field margins decreased with increasing distance to the nest, and especially dropped markedly when the distance between the nest and a field margin exceeded 100 m. Analysis of the current spatial arrangement of field margins in the landscape suggested that the area of skylark breeding habitat within 100 m of a field margin could be increased by 46%. This was due to the placement of field margins alongside unsuitable breeding habitat and to the positioning of field margins at short distances from each other. The efficiency of agri-environmental management for skylarks can likely be improved by a more careful spatial arrangement of field margins in the landscape

Do field margins enrich the diet of the Eurasian Skylark Alauda arvensis on intensive farmland?

To help restore food availability for birds, arable field margins (extensively managed strips of land sown with grasses and forbs) have been established on European farmland. In this study we describe the effect of field margins on the diet of Eurasian Skylark nestlings and adults living on intensively managed Dutch farmland. We tested the hypotheses that field margins offer a higher diversity of invertebrate prey than intensively managed crops, and that the diet of nestlings receiving food from field margins will therefore be more diverse than that of other nestlings. Field margins had a greater variety of invertebrate prey groups to offer than the intensively managed crops. Coleoptera were the most frequently and most abundantly eaten prey group by both adults and nestlings. Together, Coleoptera, Diptera, Lepidoptera, Hymenoptera and Araneae accounted for 91% of the nestling diet. Nestlings ate larger prey items and a larger proportion of larvae than adults. Almost 75% of both adults and nestlings consumed plant material, perhaps indicating a scarcity of invertebrate resources. When provided with food from field margins, the mean number of invertebrate orders in the nestling diet increased significantly from 4.7 to 5.5 and the number of families from 4.2 to 5.8 per sample. Thus, birds that used field margins for foraging could indeed provide their young with more invertebrate prey groups than birds only foraging in crops and grassland

The SUPER study: protocol for a randomised controlled trial comparing follicle-stimulating hormone and clomiphene citrate for ovarian stimulation in intrauterine insemination

Contains fulltext : 174671.pdf (publisher's version ) (Open Access)OBJECTIVE: To study the effectiveness of four cycles of intrauterine insemination (IUI) with ovarian stimulation (OS) by follicle-stimulating hormone (FSH) or by clomiphene citrate (CC), and adherence to strict cancellation criteria. SETTING: Randomised controlled trial among 22 secondary and tertiary fertility clinics in the Netherlands. PARTICIPANTS: 732 women from couples diagnosed with unexplained or mild male subfertility and an unfavourable prognosis according to the model of Hunault of natural conception. INTERVENTIONS: Four cycles of IUI-OS within a time horizon of 6 months comparing FSH 75 IU with CC 100 mg. The primary outcome is ongoing pregnancy conceived within 6 months after randomisation, defined as a positive heartbeat at 12 weeks of gestation. Secondary outcomes are cancellation rates, number of cycles with a monofollicular or with multifollicular growth, number of follicles >14 mm at the time of ovulation triggering, time to ongoing pregnancy, clinical pregnancy, miscarriage, live birth and multiple pregnancy. We will also assess if biomarkers such as female age, body mass index, smoking status, antral follicle count and endometrial aspect and thickness can be used as treatment selection markers. ETHICS AND DISSEMINATION: The study has been approved by the Medical Ethical Committee of the Academic Medical Centre and from the Dutch Central Committee on Research involving Human Subjects (CCMO NL 43131-018-13). Results will be disseminated through peer-reviewed publications and presentations at international scientific meetings. TRIAL REGISTRATION NUMBER: NTR4057