A virtual odometer for a Quadrotor Micro Aerial Vehicle

This paper describes the synthesis and evaluation of a "virtual odometer" for a Quadrotor Micro Aerial Vehicle. Availability of a velocity estimate has the potential to enhance the accuracy of mapping, estimation and control algorithms used with quadrotors, increasing the effectiveness of their applications. As a result of the unique dynamic characteristics of the quadrotor, a dual axis accelerometer mounted parallel to the propeller plane provides measurements that are directly proportional to vehicle velocities in that plane. Exploiting this insight, we encapsulate quadrotor dynamic equations which relate acceleration, attitude and the aerodynamic propeller drag in an extended Kalman filter framework for the purpose of state estimation. The result is a drift free estimation of lateral and longitudinal components of translational velocity and roll and pitch components of attitude of the quadrotor. Real world data sets gathered from two different quadrotor platforms, together with ground truth data from a Vicon system, are used to evaluate the effectiveness of the proposed algorithm and demonstrate that drift free estimates for the velocity and attitude can be obtained

Using hidden markov models to improve floor level localisation

The focus of this paper is on estimating the oor level of a robot/person moving in a multi-oor environment. It demonstrates how in- formation about transitions between oors can be employed within a probabilistic framework to improve the accuracy of oor level estimation. This is achieved by combining a simple linear classifier with a Hidden Markov Model that captures the two basic motion patterns in a multi-oor environment: Within-oor and be-Tween oors, switching from one to the other as oor transition events are detected. Through real-world experiments, we demonstrate the ability of this framework to produce accurate oor level estimates using only RSSI (Received Signal Strength Indicator) measurements, even when operating in an environment with as little as five WiFi access points per oor

Fast, on-board, model-aided visual-inertial odometry system for quadrotor micro aerial vehicles

© 2016 IEEE. The main contribution of this paper is a high frequency, low-complexity, on-board visual-inertial odometry system for quadrotor micro air vehicles. The system consists of an extended Kalman filter (EKF) based state estimation algorithm that fuses information from a low cost MEMS inertial measurement unit acquired at 200Hz and VGA resolution images from a monocular camera at 50Hz. The dynamic model describing the quadrotor motion is employed in the estimation algorithm as a third source of information. Visual information is incorporated into the EKF by enforcing the epipolar constraint on features tracked between image pairs, avoiding the need to explicitly estimate the location of the tracked environmental features. Combined use of the dynamic model and epipolar constraints makes it possible to obtain drift free velocity and attitude estimates in the presence of both accelerometer and gyroscope biases. A strategy to deal with the unobservability that arises when the quadrotor is in hover is also provided. Experimental data from a real-time implementation of the system on a 50 gram embedded computer are presented in addition to the simulations to demonstrate the efficacy of the proposed system

Effects of casoxin 4 on morphine inhibition of small animal intestinal contractility and gut transit in the mouse

Glen S Patten1,2, Richard J Head1, Mahinda Y Abeywardena1,21CSIRO Preventative Health National Research Flagship, Adelaide, Australia; 2CSIRO Food and Nutritional Sciences, Adelaide, AustraliaBackground and aims: Chronic opioid analgesia has the debilitating side-effect of constipation in human patients. The major aims of this study were to: 1) characterize the opioid-specific antagonism of morphine-induced inhibition of electrically driven contraction of the small intestine of mice, rats, and guinea pigs; and 2) test if the oral delivery of small milk-derived opioid antagonist peptides could block morphine-induced inhibition of intestinal transit in mice.Methods: Mouse, rat, and guinea pig intact ileal sections were electrically stimulated to contract and inhibited with morphine in vitro. Morphine inhibition was then blocked by opioid subtype antagonists in the mouse and guinea pig. Using a polymeric dye, Poly R-478, the opioid antagonists casoxin 4 and lactoferroxin A were tested orally for blocking activity of morphine inhibition of gut transit in vivo by single or double gavage techniques.Results: The guinea pig tissue was more sensitive to morphine inhibition compared with the mouse or the rat (IC50 [half maximal inhibitory concentration] values as nmol/L ± SEM were 34 ± 3, 230 ± 13, and 310 ± 14 respectively) (P < 0.01). The inhibitory influence of opioid agonists (IC50) in electrically driven ileal mouse preparations were DADLE ([D-Ala2, D-Leu5]-enkephalin) ≥ met-enkephalin ≥ dynorphin A ≥ DAMGO ([D-Ala2, N-Me-Phe4, Gly-ol5]-enkephalin) > morphine > morphiceptin as nmol/L 13.9, 17.3, 19.5, 23.3, 230, and 403 respectively. The mouse demonstrated predominantly Κ- and δ-opioid receptor activity with a smaller µ-opioid receptor component. Both mouse and guinea pig tissue were sensitive to casoxin 4 antagonism of morphine inhibition of contraction. In contrast to naloxone, relatively high oral doses of the µ-opioid receptor antagonists, casoxin 4 and lactoferroxin A, applied before and after morphine injection were unable to antagonize morphine inhibition of gut transit.Conclusions: Casoxin 4 reverses morphine-induced inhibition of contraction in mice and guinea pigs in vitro but fails to influence morphine inhibition of mouse small intestinal transit by the oral route.Keywords: lactoferroxin A, µ-opioid receptor antagonist, opioid agonist

Model-aided state estimation for quadrotor micro air vehicles amidst wind disturbances

© 2014 IEEE. This paper extends the recently developed Model-Aided Visual-Inertial Fusion (MA-VIF) technique for quadrotor Micro Air Vehicles (MAV) to deal with wind disturbances. The wind effects are explicitly modelled in the quadrotor dynamic equations excluding the unobservable wind velocity component. This is achieved by a nonlinear observability of the dynamic system with wind effects. We show that using the developed model, the vehicle pose and two components of the wind velocity vector can be simultaneously estimated with a monocular camera and an inertial measurement unit. We also show that the MA-VIF is reasonably tolerant to wind disturbances, even without explicit modelling of wind effects and explain the reasons for this behaviour. Experimental results using a Vicon motion capture system are presented to demonstrate the effectiveness of the proposed method and validate our claims

Localization of conductivity towards scalable and sustainable wearable electronics

Localized conductivity on fabrics is envisioned to make a shift in sustainable wearable electronics. Among the wearable electronics, localized conductivity has not been widely reported yet. Hence, we report a simple way to localize conductivity on polyester fabrics using reduced Graphene Oxide (rGO). Coupling agent, (3-aminopropyl) triethoxysilane (APTES) was used to change the chemically dormant nature of polyester fabrics, which made easy networking with GO. Then, the GO coating was substantially reduced to rGO, accomplishing conductive tracks on fabrics. rGO coated fabric showed a surface resistivity of 320 Ω/□. Even after 20 washing cycles, a significant change in surface resistivity was not observed which signifies a good wash fastness. APTES created a covalent bond network between rGO and polyester, which was proven by FTIR. This cost effective and sustainable method endows the electronic textile industry with a rapid improvement towards scalable production

Preliminary study on herpetofaunal diversity of Nilgala forest area in Monaragala district, Sri Lanka

Nilgala ForestArea (NFA) is one of the largest and important forest area in Monaragala District, UvaProvince. It contain 12,432 hectares and lies within 7° 08' - 7° 14' NL and 81 D 16' - 81020' EL. Itselevation range between 200m to 700m within the Irindahela, Hangale, Yakun hela (highest point 700rn), Hamapola, Badangarnuwa, Keenagoda, Makada, Karadugala, Kukulagoda, Ewalahela, Gorikkadahills. The mean annual rainfall varies between where the average annual rainfall 1500mm - 2000mm(rain during northeast monsoon). while the mean annual temperature of the area is 28 DC - 31°C.The vegetation comprised with lowland tropical moist semi evergreen forest and savannah forest,home gardens and small patch paddy cultivations. The dominant tree species are Aralu (Terminaliachebulav, Bulu iTerminalia bellirica) and Nelli iPhyllanthus emblicay. Other than biodiversity,Nilgala is rich of archaeological monuments, such as prehistoric, proto-historic and historical Buddhistmonasteries.During the two-year study period, total number of 70 reptile species were and 19 amphibian speciesrecorded. Reptiles include 44 genera of 17 families and 20 (28.5%) endemic species. Amphibianfauna contain 13 genera including 4 families and 6 (31.5%) endemic species. 41.4% (29) of reptilesand 26.3% (5) of Amphibians listed as 'Nationally Threatened' in the 1999 IUCN National threatenedlist. Out of70 species 38 (54.2%) are Serpentoid reptiles (11 endemics) and 32 (45.7%) species areof Tetrapod reptiles (9 endemics). Among the recorded species, 11 Serpentoid, 3 Tetrapod, and 2amphibians have not been recorded by previous workers. Furthermore seven unidentified specieswere also recorded during the survey, which probably include new amphibian species belonging togenus Nannophrys. Human activities such as man-made fire, ilIegallogging, extensive use of chemicalsfor agriculture, forest clearing for chena cultivation and road kills were identified as a main threat forthe natural habitats as well as faunal species.

Improved Mitochondrial Function with Diet-Induced Increase in Either Docosahexaenoic Acid or Arachidonic Acid in Membrane Phospholipids

Mitochondria can depolarize and trigger cell death through the opening of the mitochondrial permeability transition pore (MPTP). We recently showed that an increase in the long chain n3 polyunsaturated fatty acids (PUFA) docosahexaenoic acid (DHA; 22:6n3) and depletion of the n6 PUFA arachidonic acid (ARA; 20:4n6) in mitochondrial membranes is associated with a greater Ca2+ load required to induce MPTP opening. Here we manipulated mitochondrial phospholipid composition by supplementing the diet with DHA, ARA or combined DHA+ARA in rats for 10 weeks. There were no effects on cardiac function, or respiration of isolated mitochondria. Analysis of mitochondrial phospholipids showed DHA supplementation increased DHA and displaced ARA in mitochondrial membranes, while supplementation with ARA or DHA+ARA increased ARA and depleted linoleic acid (18:2n6). Phospholipid analysis revealed a similar pattern, particularly in cardiolipin. Tetralinoleoyl cardiolipin was depleted by 80% with ARA or DHA+ARA supplementation, with linoleic acid side chains replaced by ARA. Both the DHA and ARA groups had delayed Ca2+-induced MPTP opening, but the DHA+ARA group was similar to the control diet. In conclusion, alterations in mitochondria membrane phospholipid fatty acid composition caused by dietary DHA or ARA was associated with a greater cumulative Ca2+ load required to induced MPTP opening. Further, high levels of tetralinoleoyl cardiolipin were not essential for normal mitochondrial function if replaced with very-long chain n3 or n6 PUFAs