3,074 research outputs found
High Performance P3M N-body code: CUBEP3M
This paper presents CUBEP3M, a publicly-available high performance
cosmological N-body code and describes many utilities and extensions that have
been added to the standard package. These include a memory-light runtime SO
halo finder, a non-Gaussian initial conditions generator, and a system of
unique particle identification. CUBEP3M is fast, its accuracy is tuneable to
optimize speed or memory, and has been run on more than 27,000 cores, achieving
within a factor of two of ideal weak scaling even at this problem size. The
code can be run in an extra-lean mode where the peak memory imprint for large
runs is as low as 37 bytes per particles, which is almost two times leaner than
other widely used N-body codes. However, load imbalances can increase this
requirement by a factor of two, such that fast configurations with all the
utilities enabled and load imbalances factored in require between 70 and 120
bytes per particles. CUBEP3M is well designed to study large scales
cosmological systems, where imbalances are not too large and adaptive
time-stepping not essential. It has already been used for a broad number of
science applications that require either large samples of non-linear
realizations or very large dark matter N-body simulations, including
cosmological reionization, halo formation, baryonic acoustic oscillations, weak
lensing or non-Gaussian statistics. We discuss the structure, the accuracy,
known systematic effects and the scaling performance of the code and its
utilities, when applicable.Comment: 20 pages, 17 figures, added halo profiles, updated to match MNRAS
accepted versio
SKA HI end2end simulation
The current status of the HI simulation efforts is presented, in which a self
consistent simulation path is described and basic equations to calculate array
sensitivities are given. There is a summary of the SKA Design Study (SKADS) sky
simulation and a method for implementing it into the array simulator is
presented. A short overview of HI sensitivity requirements is discussed and
expected results for a simulated HI survey are presented.Comment: 7 pages, 6 figues, need skads2009.cls file to late
Real-Time Trigger and online Data Reduction based on Machine Learning Methods for Particle Detector Technology
Moderne Teilchenbeschleuniger-Experimente generieren während zur Laufzeit immense Datenmengen. Die gesamte erzeugte Datenmenge abzuspeichern, überschreitet hierbei schnell das verfügbare Budget für die Infrastruktur zur Datenauslese. Dieses Problem wird üblicherweise durch eine Kombination von Trigger- und Datenreduktionsmechanismen adressiert. Beide Mechanismen werden dabei so nahe wie möglich an den Detektoren platziert um die gewünschte Reduktion der ausgehenden Datenraten so frühzeitig wie möglich zu ermöglichen. In solchen Systeme traditionell genutzte Verfahren haben währenddessen ihre Mühe damit eine effiziente Reduktion in modernen Experimenten zu erzielen. Die Gründe dafür liegen zum Teil in den komplexen Verteilungen der auftretenden Untergrund Ereignissen. Diese Situation wird bei der Entwicklung der Detektorauslese durch die vorab unbekannten Eigenschaften des Beschleunigers und Detektors während des Betriebs unter hoher Luminosität verstärkt. Aus diesem Grund wird eine robuste und flexible algorithmische Alternative benötigt, welche von Verfahren aus dem maschinellen Lernen bereitgestellt werden kann. Da solche Trigger- und Datenreduktion-Systeme unter erschwerten Bedingungen wie engem Latenz-Budget, einer großen Anzahl zu nutzender Verbindungen zur Datenübertragung und allgemeinen Echtzeitanforderungen betrieben werden müssen, werden oft FPGAs als technologische Basis für die Umsetzung genutzt. Innerhalb dieser Arbeit wurden mehrere Ansätze auf Basis von FPGAs entwickelt und umgesetzt, welche die vorherrschenden Problemstellungen für das Belle II Experiment adressieren. Diese Ansätze werden über diese Arbeit hinweg vorgestellt und diskutiert werden
GUARDIANS final report
Emergencies in industrial warehouses are a major concern for firefghters. The large dimensions together with the development of dense smoke that drastically reduces visibility, represent major challenges. The Guardians robot swarm is designed to assist fire fighters in searching a
large warehouse. In this report we discuss the technology developed for a swarm of robots searching and assisting fire fighters. We explain the swarming algorithms which provide the functionality by which the robots react to and follow humans while no communication is required. Next we
discuss the wireless communication system, which is a so-called mobile ad-hoc network. The communication network provides also one of the means to locate the robots and humans. Thus the robot swarm is able to locate itself and provide guidance information to the humans. Together with
the re ghters we explored how the robot swarm should feed information back to the human fire fighter. We have designed and experimented with interfaces for presenting swarm based information to human beings
The Spine of the Cosmic Web
We present the SpineWeb framework for the topological analysis of the Cosmic
Web and the identification of its walls, filaments and cluster nodes. Based on
the watershed segmentation of the cosmic density field, the SpineWeb method
invokes the local adjacency properties of the boundaries between the watershed
basins to trace the critical points in the density field and the separatrices
defined by them. The separatrices are classified into walls and the spine, the
network of filaments and nodes in the matter distribution. Testing the method
with a heuristic Voronoi model yields outstanding results. Following the
discussion of the test results, we apply the SpineWeb method to a set of
cosmological N-body simulations. The latter illustrates the potential for
studying the structure and dynamics of the Cosmic Web.Comment: Accepted for publication HIGH-RES version:
http://skysrv.pha.jhu.edu/~miguel/SpineWeb
UNDERWATER OBJECT DETECTION BASED ON DISTANCE MEASUREMENT USING ULTRASONIC
Detecting the underwater object with Sound Navigation and Ranging (SONAR) in various fields such as fisheries, maritime, oil and gas industry, and autonomous underwater vehicles. SONAR is needed for detecting the underwater object for a larger area by determining object characteristics (e.g. The object sizes and the object types). This thesis also uses a 1-Dimensional technique to identify the underwater object visual information such as the shape of the object. SONAR is a technique for detecting objects that are buried under the water surface by using the sound signal that is reflected on the object to locating the object and knowing the shape of the object.
This thesis is to observe a SONAR system on detecting the underwater object by obtaining information on the object distance and the object dimension to the data processor. The object detection experiments with different distances are conducted on water medium at Situ-Techno and swimming pool of Telkom University. The objects are alumunium and ceramics. The working frequency of the AJ-SR04M module with a fish finder transducer sensor is 40 KHz with a minimum detection distance of 20 cm and a maximum distance of 800 cm. To use the sensor, we must program the sensor on the microcontroller.
By the performance of underwater object detection at finding the information of the object position distance and the object dimension. The first experiment will show the sensor accuracy value on detecting the object by comparing the actual distance with the reference distance to the object is capable to detecting the object position distance with accuracy level for alumunium position distance is around
92.85% to 98.73% and for ceramics is around 84.61% to 88.71%. The second ex- periment will show the dimension of the object we should determine the horizontal plane and the vertical plane to know the shape of the object and the inclination angle between the first sensor and the second sensor on alumunium is around 21.30? and for ceramics is around 22.60?.
Keywords: Underwater Object Detection, SONAR, Arduino Mega 2560, AJ- SR04M Waterproof Ultrasonic Module
Mechatronic Systems
Mechatronics, the synergistic blend of mechanics, electronics, and computer science, has evolved over the past twenty five years, leading to a novel stage of engineering design. By integrating the best design practices with the most advanced technologies, mechatronics aims at realizing high-quality products, guaranteeing at the same time a substantial reduction of time and costs of manufacturing. Mechatronic systems are manifold and range from machine components, motion generators, and power producing machines to more complex devices, such as robotic systems and transportation vehicles. With its twenty chapters, which collect contributions from many researchers worldwide, this book provides an excellent survey of recent work in the field of mechatronics with applications in various fields, like robotics, medical and assistive technology, human-machine interaction, unmanned vehicles, manufacturing, and education. We would like to thank all the authors who have invested a great deal of time to write such interesting chapters, which we are sure will be valuable to the readers. Chapters 1 to 6 deal with applications of mechatronics for the development of robotic systems. Medical and assistive technologies and human-machine interaction systems are the topic of chapters 7 to 13.Chapters 14 and 15 concern mechatronic systems for autonomous vehicles. Chapters 16-19 deal with mechatronics in manufacturing contexts. Chapter 20 concludes the book, describing a method for the installation of mechatronics education in schools
Simulations of the Microwave Sky
We create realistic, full-sky, half-arcminute resolution simulations of the
microwave sky matched to the most recent astrophysical observations. The
primary purpose of these simulations is to test the data reduction pipeline for
the Atacama Cosmology Telescope (ACT) experiment; however, we have widened the
frequency coverage beyond the ACT bands to make these simulations applicable to
other microwave background experiments. Some of the novel features of these
simulations are that the radio and infrared galaxy populations are correlated
with the galaxy cluster populations, the CMB is lensed by the dark matter
structure in the simulation via a ray-tracing code, the contribution to the
thermal and kinetic Sunyaev-Zel'dovich (SZ) signals from galaxy clusters,
groups, and the IGM has been included, and the gas prescription to model the SZ
signals matches the most recent X-ray observations. Regarding the contamination
of cluster SZ flux by radio galaxies, we find for 148 GHz (90 GHz) only 3% (4%)
of halos have their SZ decrements contaminated at a level of 20% or more. We
find the contamination levels higher for infrared galaxies. However, at 90 GHz,
less than 20% of clusters with M_{200} > 2.5 x 10^{14} Msun and z<1.2 have
their SZ decrements filled in at a level of 20% or more. At 148 GHz, less than
20% of clusters with M_{200} > 2.5 x 10^{14} Msun and z<0.8 have their SZ
decrements filled in at a level of 50% or larger. Our models also suggest that
a population of very high flux infrared galaxies, which are likely lensed
sources, contribute most to the SZ contamination of very massive clusters at 90
and 148 GHz. These simulations are publicly available and should serve as a
useful tool for microwave surveys to cross-check SZ cluster detection, power
spectrum, and cross-correlation analyses.Comment: Sims are now public at
http://lambda.gsfc.nasa.gov/toolbox/tb_cmbsim_ov.cfm; Expanded discussion of
N-body sim and IGM; Version accepted by Ap
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