158 research outputs found
GPS-SLAM: An augmentation of the ORB-SLAM algorithm
This work presents Global Positioning System-Simultaneous Localization and Mapping (GPS-SLAM), an augmented version of Oriented FAST (Features from accelerated segment test) and Rotated BRIEF (Binary Robust Independent Elementary Features) feature detector (ORB)-SLAM using GPS and inertial data to make the algorithm capable of dealing with low frame rate datasets. In general, SLAM systems are successful in case of datasets with a high frame rate. This work was motivated by a scarce dataset where ORB-SLAM often loses track because of the lack of continuity. The main work includes the determination of the next frame’s pose based on the GPS and inertial data. The results show that this additional information makes the algorithm more robust. As many large, outdoor unmanned aerial vehicle (UAV) flights save the GPS and inertial measurement unit (IMU) data of the capturing of images, this program gives an option to use the SLAM algorithm successfully even if the dataset has a low frame rate
On the apsidal motion of BP Vulpeculae
BP Vulpeculae is a bright eclipsing binary system showing apsidal motion. It
was found in an earlier study that it shows retrograde apsidal motion which
contradicts theory. In this paper we present the first light curve of the
system and its light curve solution as well as seven new times of the minima
from the years 1959-1963. This way we could expanded the baseline of the
investigation to five decades. Based on this longer baseline we concluded that
the apsidal motion is prograde agreeing with the theoretical expectations and
its period is about 365 years and the determined internal structure constant is
close to the theoretically expected one.Comment: accepted for New Astronomy; two figure
Adsorption of organic acids on magnetite nanoparticles, pH-dependent colloidal stability and salt tolerance
The adsorption of different organic acids and their influence on the pH-dependent charging, salt tolerance and so the colloidal stability of magnetite nanoparticles are compared. Adsorption isotherms of citric acid - CA, gallic acid - GA, poly(acrylic acid) - PAA, poly(acrylic-co-maleic acid) - PAM and humic acid - HA were measured. The pH-dependent charge state of MNPs was characterized by electrophoretic mobility and their aggregation by dynamic light scattering. The salt tolerance was tested in coagulation kinetic experiments. Although the adsorption capacities, the type of bonding (either H-bonds or metal ion-carboxylate complexes) and so the bond strengths are significantly different, the following general trends have been found. Small amount of organic acids at pH. <. ~8 (the pH of PZC of magnetite) - relevant condition in natural waters - only neutralize. s the positive charges, and so promotes the aggregation and sedimentation of nanoparticles. Greater amounts of organic acid, above the charge neutralization, cause the sign reversal of particle charge, and at high overcharging promote stabilization and dispersing. The thicker layer of PAA, PAM and HA provides better electrosteric stability than CA and GA. GA undergoes surface polymerization, thereby improving stabilization. The organic acids studied here eliminate completely the pH sensitivity of amphoteric magnetite, but only the polyanionic coverage provides significant increase in resistance against coagulating effects of salts at neutral pH commonly prevailing in natural waters
Atomic Layer Deposition (ALD) to Mitigate Tin Whisker Growth and Corrosion Issues on Printed Circuit Board Assemblies
This paper presents the results of a research program set up to evaluate atomic layer deposition (ALD) conformal coatings as a method of mitigating the growth of tin whiskers from printed circuit board assemblies. The effect of ALD coating process variables on the ability of the coating to mitigate whisker growth were evaluated. Scanning electron microscopy and optical microscopy were used to evaluate both the size and distribution of tin whiskers and the coating/whisker interactions. Results show that the ALD process can achieve significant reductions in whisker growth and thus offers considerable potential as a reworkable whisker mitigation strategy. The effect of ALD layer thickness on whisker formation was also investigated. Studies indicate that thermal exposure during ALD processing may contribute significantly to the observed whisker mitigation
A mikroflóra és a bélnyálkahártya kölcsönhatása az irritábilis bél, irritábilis szem és irritábilis elme szindróma kórtanában és kezelésében
Accumulating clinical evidence supports co-morbidity of irritable bowel, irritable eye and irritable mind symptoms. Furthermore, perturbation of the microbiota-host symbiosis (dysbiosis) is considered a common pathogenic mechanism connecting gastrointestinal, ocular and neuropsychiatric symptoms. Consequently, maintaining or restoring microbiota-host symbiosis represents a new approach to treat these symptoms or to prevent their relapses. Current treatment approach assigned a primary role to live probiotics alone or in combination with prebiotics to enhance colonization of beneficial bacteria and to strengthen the symbiosis. However, several papers showed major benefits of heat-killed probiotics as compared to their live counterparts on both intestinal and systemic symptoms. Recently, in addition to killing probiotics, in a proof of concept study lysates (fragments) of probiotics in combination with vitamins A, B, D and omega 3 fatty acids were successfully tested. These findings suggested a conceptual change in the approach addressed to both the microbiota and host as targets for intervention. Orv. Hetil., 2014, 155(37), 1454-1460
Sicherung der logistikqualität
Der nachfolgende Beitrag beleuchtet einen Forschungs- und Ausbildungsschwerpunkt der drei kooperierenden Universitäten. Dabei geht es um die Erforschung der Nutzung des Methoden vorrats (Vgl. [1]) von Qualitätsmanagement und Logistik im jeweils anderen Applikationsbereich. Die Forschungsarbeiten werden seit 2003 systematisch und arbeitsteilig durch-geführt. Durch synergetische Verknüpfung und zu leistende Systematisierungen sollen die bekannten Einsatzgebiete erweitert bzw. modifiziert sowie gänzlich neue Einsatzgebiete erschlossen werden. Gleichzeitig soll ein wesentlicher Beitrag zur Sicherung der Qualität in der Logistik geleistet werden.Um das gesammelte Wissen unmittelbar in der Aus- und Weiterbildung zu nutzen, wurde das Manuskript für ein gemeinsames Lehrbuch „Qualitätssicherung in der Logistik“ in den Sprachen ungarisch und deutsch fertig gestellt. Darüber hinaus werden erprobte Methoden in die gemeinsame webbasierte Methodendatenbank mlog eingestellt und für eine multivariate Nutzung zur Verfügung gestellt.Дана робота висвітлює дослідницькі й освітні завдання трьох університетів, що співробітничають між собою. При цьому мова йде про дослідження використання наявностей, що є в наявності (див [1]) керування якістю й логістики в інших сферах застосування. Дослідницькі роботи ведуться з 2003 року систематично й на основі поділу праці. Шляхом синегретического об'єднання й систематизації варто розширити, тобто модифікувати відомі області застосування, а також відкрити зовсім нові області застосування. Одночасно варто внести значний вклад у забезпечення якості в логістиці. Для того щоб використати накопичені знання безпосередньо в процесі навчання або підвищення кваліфікації, був підготовлений рукопис для загального навчального посібника "Забезпечення якості в логістиці" на угорській і німецькій мовах. Із цією метою були встановлені випробувані методи в електронному банку даних, які були підготовлені для безпосереднього використання
Simulating Dynamical Features of Escape Panic
One of the most disastrous forms of collective human behaviour is the kind of
crowd stampede induced by panic, often leading to fatalities as people are
crushed or trampled. Sometimes this behaviour is triggered in life-threatening
situations such as fires in crowded buildings; at other times, stampedes can
arise from the rush for seats or seemingly without causes. Tragic examples
within recent months include the panics in Harare, Zimbabwe, and at the
Roskilde rock concert in Denmark. Although engineers are finding ways to
alleviate the scale of such disasters, their frequency seems to be increasing
with the number and size of mass events. Yet, systematic studies of panic
behaviour, and quantitative theories capable of predicting such crowd dynamics,
are rare. Here we show that simulations based on a model of pedestrian
behaviour can provide valuable insights into the mechanisms of and
preconditions for panic and jamming by incoordination. Our results suggest
practical ways of minimising the harmful consequences of such events and the
existence of an optimal escape strategy, corresponding to a suitable mixture of
individualistic and collective behaviour.Comment: For related information see http://angel.elte.hu/~panic,
http://www.helbing.org, http://angel.elte.hu/~fij, and
http://angel.elte.hu/~vicse
Parabolic Target-Space Interior-Point Algorithm for Weighted Monotone Linear Complementarity Problem
In this paper, we revisit the main principles for constructing polynomial-time primal-dual interior-point algorithms (IPAs). Starting from the break-through paper by Gonzaga (1989), their development was related to the barrier methods, where the objective function was added to the barrier for the feasible set. With this construction, using the theory of self-concordant functions proposed by Nesterov and Nemirovski (1994), it was possible to develop different variants of IPAs for a large variety of convex problems. However, in order to solve the initial problem, the most efficient primal-dual methods need to follow several central paths (up to three), which correspond to different stages of the solution process. This multistage structure of the methods significantly reduces their efficiency. In this paper, we come back to the initial idea by Renegar (1988) of using the methods of centers. We implement it for the weighted Linear Complementarity Problem (WLCP), by extending the framework of Parabolic Target Space (PTS), proposed by Nesterov (2008) for primal-dual Linear Programming Problems. This approach has several advantages. It starts from an arbitrary strictly feasible primal-dual pair and travels directly to the solution of the problem in one stage. It has the best known worst-case complexity bound. Finally, it works in a large neighborhood of the deviated central path, allowing very large steps. The latter ability results in a significant acceleration in the end of the process, confirmed by our preliminary computational experiments
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