Virtual plaster cast : digital 3D modelling of lion paws and tracks using close-range photogrammetry

The ecological monitoring of threatened species is vital for their survival as it provides the baselines for conservation, research and management strategies. Wildlife studies using tracks are controversial mainly due to unreliable recording techniques limited to two-dimensions (2D). We assess close-range photogrammetry as a lowcost, rapid, practical and reliable field technique for the digital three-dimensional (3D) modelling of lion Panthera leo paws and tracks. First, we tested three reconstruction parameters affecting the 3D model quality. We then compared direct measurements on the paws and tracks versus the same measurements on their digital 3D models. Finally, we assessed the minimum number of photographs required for the 3D reconstruction. Masking, auto-calibration and optimization provided higher reconstruction quality. Paws masked semi-automatically and tracks masked manually were characterized by a geometric deviation of 0.23 0.18 cm and 0.50 0.33 cm respectively. Unmasked tracks delineated by means of the contour lines had a geometric deviation of 0.06 0.39 cm. The use of a correction factor reduced the geometric deviation to 0.03 0.20 cm (pad-masked paws), 0.04 0.35 cm (pad-masked tracks) and 0.01 0.39 cm (unmasked tracks). Based on the predicted error, the minimum number of photographs required for an accurate reconstruction is seven (paws) or eight (tracks) photographs. This field technique, using only a digital camera and a ruler, takes less than one minute to sample a paw or track. The introduction of the 3D facet provides more realistic replications of paws and tracks that will enable a better understanding of their intrinsic properties and variation due to external factors. This advanced recording technique will permit a refinement of the current methods aiming at identifying species, age, sex and individual from tracks.National Research Foundation (NRF).http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1469-79982017-02-28hb2016Mammal Research InstituteZoology and Entomolog

Precision scans of the pixel cell response of double sided 3D pixel detectors to pion and x-ray beams

hree-dimensional (3D) silicon sensors offer potential advantages over standard planar sensors for radiation hardness in future high energy physics experiments and reduced charge-sharing for X-ray applications, but may introduce inefficiencies due to the columnar electrodes. These inefficiencies are probed by studying variations in response across a unit pixel cell in a 55μm pitch double-sided 3D pixel sensor bump bonded to TimePix and Medipix2 readout ASICs. Two complementary characterisation techniques are discussed: the first uses a custom built telescope and a 120GeV pion beam from the Super Proton Synchrotron (SPS) at CERN; the second employs a novel technique to illuminate the sensor with a micro-focused synchrotron X-ray beam at the Diamond Light Source, UK. For a pion beam incident perpendicular to the sensor plane an overall pixel efficiency of 93.0±0.5% is measured. After a 10o rotation of the device the effect of the columnar region becomes negligible and the overall efficiency rises to 99.8±0.5%. The double-sided 3D sensor shows significantly reduced charge sharing to neighbouring pixels compared to the planar device. The charge sharing results obtained from the X-ray beam study of the 3D sensor are shown to agree with a simple simulation in which charge diffusion is neglected. The devices tested are found to be compatible with having a region in which no charge is collected centred on the electrode columns and of radius 7.6±0.6μm. Charge collection above and below the columnar electrodes in the double-sided 3D sensor is observed

Identification of the anteroposterior and mediolateral position of lion paws and tracks using 3D geometric morphometrics

Estimating the distribution and status of animal populations is crucial in various fields of biology. Monitoring species via their tracks is controversial due to unreliable recording techniques, manipulator bias and substrate variation. Furthermore, subjective identification of the foot that produces each track can lead to significant errors, for example, when assigning tracks made by different feet from the same individual to different individuals. The aim of this research was to develop an accurate, consistent and objective algorithm to identify the anteroposterior (hind/front) and mediolateral (right/left) position from digital threedimensional (3D) models of African lion (Panthera leo) paws and tracks using geometric morphometrics. We manually positioned 12 fixed landmarks on 132 paws and 182 tracks recorded in 3D using digital close-range photogrammetry. We used geometric morphometrics to evaluate and visualize the shape variation between paws and between tracks along the anteroposterior and mediolateral axes, and between paws and tracks. The identification algorithm using linear discriminant analysis with jack-knifed predictions reached a maximum accuracy of 95.45% and 91.21% for paws and tracks, respectively.We recommend the use of this objective position identification algorithm in future studies where tracks are compared between individual African lions

Legal Challenges Surrounding Maritime Operations in the Mediterranean Sea: Focus on Migrant Flows

Over time the nature of military and maritime operations has shifted from traditional warfare to hybrid type of operations including non-traditional forms of military action such as law enforcement activities. The changing character of operations also impacts the applicable legal framework making the conduct of these operations more challenging from an operators point of view. This article sheds light on the legal challenges that accompany the change in operations to migrant flow operations. A case in point are recent maritime operations focused on migrant flows conducted in de Mediterranean Sea, in particular the European Union mandated Operation Sophia, in which the Royal Netherlands Navy is involved, although not on a continuous basis.

Legal challenges surrounding maritime operations in the Mediterranean Sea: focus on migrant flows

Over time the nature of military and maritime operations has shifted from traditional warfare to hybrid type of operations including non-traditional forms of military action such as law enforcement activities. The changing character of operations also impacts the applicable legal framework making the conduct of these operations more challenging from an operators point of view. This article sheds light on the legal challenges that accompany the change in operations to migrant flow operations. A case in point are recent maritime operations focused on migrant flows conducted in de Mediterranean Sea, in particular the European Union mandated Operation Sophia, in which the Royal Netherlands Navy is involved, although not on a continuous basis.

Linkage between fishes'foraging, market and fish stocks density: Examples from some North Sea fisheries

This study has investigated some properties of fishermen's foraging, using Levy flights theory. The case studies examined were a selection of North Sea Dutch and French vessels, for which catch and effort data were collected on a haul-by-haul basis. Foraging behavior could reasonably be represented by a Levy flight process, characterized by an exponentiation factor ¿, for both fleets. The properties of fishers' foraging were further investigated for the Dutch fleet using time series analysis. Optimal foraging was found with = 1.5, suggesting a slow recovery dynamics of the stocks being harvested. Efficient foraging led to high value per unit effort, while the knowledge of fishing grounds with high stock density is shown to increase foraging efficiency in the short-term future. Only marginal correlations could be found between ¿ and the other explanatory variables considered (fish prices and fishing effort)

NL ARMS Netherlands Annual Review of Military Studies 2018. Coastal Border Control: from data and tasks to deployment and law enforcement

This book provides a comprehensive study of border control: from data analysis and information warfare, frameworks for command and control, and game-theoretic risk management, up to the (optimal) deployment of law enforcement missions. Innovative about this book is that it approaches the subject from several angles, aiming to connect theory and practice of law enforcement missions with risk management and/or quantitative modelling. Some chapters focus on legal challenges and informationwarfare, while others provide quantitative modelling of military asset deployment inthe area of interest, or show the benefits of cooperative wireless sensor networks forborder control. A case study of the Dutch Border Security Team supplements the theory