Preliminary space mission design under uncertainty

This paper proposes a way to model uncertainties and to introduce them explicitly in the design process of a preliminary space mission. Traditionally, a system margin approach is used in order to take them into account. In this paper, Evidence Theory is proposed to crystallise the inherent uncertainties. The design process is then formulated as an Optimisation Under Uncertainties (OUU). Three techniques are proposed to solve the OUU problem: (a) an evolutionary multi-objective approach, (b) a step technique consisting of maximising the belief for different levels of performance, and (c) a clustering method that firstly identifes feasible regions. The three methods are applied to the BepiColombo mission and their effectiveness at solving the OUU problem are compared

MANAGEMENT OF COYOTES FOR PRONGHORN?

Coyotes (Canis latrans) and pronghorn (Antilocapra americana) have co-existed for thousands of years, but in today\u27s production-oriented society the Pronghorn may need some help periodically. Although pronghorn numbers have rebounded dramatically since the early 20th century, continued management of this species is necessary and may include management of its primarily predator, the coyote. Pronghorn defense mechanisms offer protection from predators, but the coyote\u27s hunting strategies overcome these mechanisms The Trans-Pecos region of Texas holds the greatest numbers of pronghorn In the state. Ranchers in the Trans-Pecos can use predators, such as rainfall; strategies, such as proper livestock stocking rates and pasture deferment; and tools, such as predator control, to help manage pronghorn populations in the presence of coyotes

MANAGEMENT OF COYOTES FOR PRONGHORN?

Coyotes (Canis latrans) and pronghorn (Antilocapra americana) have co-existed for thousands of years, but in today\u27s production-oriented society the Pronghorn may need some help periodically. Although pronghorn numbers have rebounded dramatically since the early 20th century, continued management of this species is necessary and may include management of its primarily predator, the coyote. Pronghorn defense mechanisms offer protection from predators, but the coyote\u27s hunting strategies overcome these mechanisms The Trans-Pecos region of Texas holds the greatest numbers of pronghorn In the state. Ranchers in the Trans-Pecos can use predators, such as rainfall; strategies, such as proper livestock stocking rates and pasture deferment; and tools, such as predator control, to help manage pronghorn populations in the presence of coyotes

Inquiry Into Use and Importance of R&D Tax Incentives in British Columbia

This is a report about the experiences of a sampling of BC companies with Federal R&D tax incentives. It is based on responses to a survey conducted during a workshop sponsored by the Science Council of British Columbia through its SPARK program on the topic of Venture Funding Alternatives: Financial Options for Funding Technology-Based Companies

Mission design for LISA Pathfinder

Here we describe the mission design for SMART-2/LISA Pathfinder. The best trade-off between the requirements of a low-disturbance environment and communications distance is found to be a free-insertion Lissajous orbit around the first co-linear Lagrange point of the Sun-Earth system L1, 1.5x 10^6 km from Earth. In order to transfer SMART-2/LISA Pathfinder from a low Earth orbit, where it will be placed by a small launcher, the spacecraft carries out a number of apogee-raise manoeuvres, which ultimatively place it to a parabolic escape trajectory towards L1. The challenges of the design of a small mission are met, fulfilling the very demanding technology demonstration requirements without creating excessive requirements on the launch system or the ground segment.Comment: 7 pages, 6 figures, 5th International LISA Symposium, see http://www.landisoft.de/Markus-Landgra

FOOD HABITS OF MOUNTAIN LIONS IN THE TRANS-PECOS REGION OF TEXAS

Information regarding mountain lion (Felis concolor) food habits is relatively scarce overall, and this is particularly true in the Trans-Pecos region of Texas. Most information currently available is from Big Bend National Park where livestock are excluded and game animals are not actively managed. This study involved the analysis of 32 mountain lion stomachs collected throughout the Trans-Pecos over a 14 month period. Deer (Odocoileus spp.) and javelina (Tayassu tajacu) were the predominate prey species, each occurring in 39% of the stomachs analyzed. Domestic livestock was found in 9% of the total stomachs and non-game wildlife in 13%. Samples taken from areas with and without livestock differed significantly (P\u3c0.05). Samples from areas with livestock contained deer (50%), javelina (19%), small game (19%), and livestock (12%). Samples from areas without livestock contained javelina (86%) and deer (14%). No differences (P\u3e0.05) in food habits were found between sexes or among seasons of the year

FOOD HABITS OF MOUNTAIN LIONS IN THE TRANS-PECOS REGION OF TEXAS

Information regarding mountain lion (Felis concolor) food habits is relatively scarce overall, and this is particularly true in the Trans-Pecos region of Texas. Most information currently available is from Big Bend National Park where livestock are excluded and game animals are not actively managed. This study involved the analysis of 32 mountain lion stomachs collected throughout the Trans-Pecos over a 14 month period. Deer (Odocoileus spp.) and javelina (Tayassu tajacu) were the predominate prey species, each occurring in 39% of the stomachs analyzed. Domestic livestock was found in 9% of the total stomachs and non-game wildlife in 13%. Samples taken from areas with and without livestock differed significantly (P\u3c0.05). Samples from areas with livestock contained deer (50%), javelina (19%), small game (19%), and livestock (12%). Samples from areas without livestock contained javelina (86%) and deer (14%). No differences (P\u3e0.05) in food habits were found between sexes or among seasons of the year

Electrical expression of spin accumulation in ferromagnet/semiconductor structures

We treat the spin injection and extraction via a ferromagnetic metal/semiconductor Schottky barrier as a quantum scattering problem. This enables the theory to explain a number of phenomena involving spin-dependent current through the Schottky barrier, especially the counter-intuitive spin polarization direction in the semiconductor due to current extraction seen in recent experiments. A possible explanation of this phenomenon involves taking into account the spin-dependent inelastic scattering via the bound states in the interface region. The quantum-mechanical treatment of spin transport through the interface is coupled with the semiclassical description of transport in the adjoining media, in which we take into account the in-plane spin diffusion along the interface in the planar geometry used in experiments. The theory forms the basis of the calculation of spin-dependent current flow in multi-terminal systems, consisting of a semiconductor channel with many ferromagnetic contacts attached, in which the spin accumulation created by spin injection/extraction can be efficiently sensed by electrical means. A three-terminal system can be used as a magnetic memory cell with the bit of information encoded in the magnetization of one of the contacts. Using five terminals we construct a reprogrammable logic gate, in which the logic inputs and the functionality are encoded in magnetizations of the four terminals, while the current out of the fifth one gives a result of the operation.Comment: A review to appear in Mod. Phys. Lett.

Low-thrust approach and gravitational capture at mercury

ABSTRACT BepiColombo, an ESA science mission, will reach Mercury in early 2017. The complex nearly 5-year long transfer consists of 6 flybys and many extended thrust arcs where the spacecraft is accelerated by solar electric propulsion. The thrust level is too low for a capture from a hyperbolic approach. To avoid a single point failure of a classical chemical orbit insertion burn, a trajectory is proposed where the gravity of the Sun is exploited to weakly capture the spacecraft in a Mercury orbit. The arrival conditions are optimised taking into account the interplanetary delta-V and low-cost recovery options in case of a failed orbit insertion. Finally, the navigation aspects for this unusual approach trajectory are studied