Solving a Deconvolution Problem in Photon Spectrometry Aleksandrov, D.; Alme, J.; Basmanov, V. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2010, Letnik:
620, Številka:
2
Journal Article
Recenzirano
We solve numerically a deconvolution problem to extract the undisturbed spectrum from the measured distribution contaminated by the finite resolution of the measuring device. A problem of this kind ...emerges when one wants to infer the momentum distribution of the neutral pions by detecting the
π
0
decay photons using the photon spectrometer of the ALICE LHC experiment at CERN
1. The underlying integral equation connecting the sought for pion spectrum and the measured gamma spectrum has been discretized and subsequently reduced to a system of linear algebraic equations. The latter system, however, is known to be ill-posed and must be regularized to obtain a stable solution. This task has been accomplished here by means of the Tikhonov regularization scheme combined with the L-curve method. The resulting pion spectrum is in an excellent quantitative agreement with the pion spectrum obtained from a Monte Carlo simulation.
We propose to use a set of general purpose computing (GPC), communication and multimedia devices such as laptops, tablets, PDAs, smart phones, audio recorders, and camcorders as a distributed array ...signal processing system. A novel scheme is developed to synchronize input and output sampling for a network of distributed multi-channel audio sensors and actuators. IEEE 802.11 wireless network is used to deliver the global clock and data streams to distributed GPC platforms, while an interrupt timestamping mechanism is employed to distribute the common clock between I/O devices. Adaptive statistical processing is applied to reduce the effect of timing errors inevitable on real-life platforms. A prototype of distributed array is implemented based on Intel®Centrino™laptops and experimental results demonstrate a precision in A/D and D/A synchronization better than 50 μs (a couple of samples at 48 kHz).
We propose a novel synchronization scheme for distributed audio-video input and output on heterogeneous general purpose computers (GPC) such as laptops, tablets, PDA, smart telephones, audio ...recorders, and camcorders. These devices typically possess sensors such as microphones and possibly cameras, and actuators such as loudspeakers and displays. In order to combine them wirelessly into a distributed array signal processing system, it is necessary to provide relative time synchronization to sensors and actuators. In this work we propose a setup and an algorithm to synchronize input and output for a network of distributed multichannel audio sensors and actuators connected to GPC. An IEEE 802.11 wireless network is used to deliver the global clock to distributed GPC, while the interrupt mechanism is employed to distribute the clock between I/O devices. Experimental results demonstrate a precision in A/D D/A synchronization precision better than 50 /spl mu/s (a couple of samples at 48 kHz).
The recent emergence of multi-core processors enables a new trend in the usage of computers. Computer vision applications, which require heavy computation and lots of bandwidth, usually cannot run in ...real-time. Recent multi-core processors can potentially serve the needs of such workloads. In addition, more advanced algorithms can be developed utilizing the new computation paradigm. In this paper, we study the performance of an articulated body tracker on multi-core processors. The articulated body tracking workload encapsulates most of the important aspects of a computer vision workload. It takes multiple camera inputs of a scene with a single human object, extracts useful features, and performs statistical inference to find the body pose. We show the importance of properly parallelizing the workload in order to achieve great performance: speedups of 26 on 32 cores. We conclude that: (1) data-domain parallelization is better than function-domain parallelization for computer vision applications; (2) data-domain parallelism by image regions and particles is very effective; (3) reducing serial code in edge detection brings significant performance improvements; (4) domain knowledge about low/mid/high level of vision computation is helpful in parallelizing the workload.
Implementation of energy saving process postharvest processing of grain due to the construction of automatic control systems for the effective operation of which requires knowledge of the behavior of ...the material being processed under the influence factors used. The absence of these data leads to a waste of energy, as well as the decline in the quality of the final product. In this case, drying is often one of the most processes in the production of cereals. This study aimed at obtaining the dynamic properties of the grain mass during drying by electromagnetic waves.
Array audio-visual signal processing algorithms require time-synchronized capture of AV-data on distributed platforms. In addition, the geometry of the array of cameras, microphones, speakers and ...displays is often required. In this chapter we present a novel setup involving network of wireless computing platforms with sensors and actuators onboard, and algorithms that can provide both synchronized I/O and self-localization of the I/O devices in 3D space. The proposed algorithms synchronize input and output for a network of distributed multi-channel audio sensors and actuators connected to general purpose computing platforms (GPCs) such as laptops, PDAs and tablets. IEEE 802.11 wireless network is used to deliver the global clock to distributed GPCs, while the interrupt timestamping mechanism is employed to distribute the clock between I/O devices. Experimental results demonstrate a precision in A/D D/A synchronization precision better than 50 μs (a couple of samples at 48 kHz). We also present a novel algorithm to automatically determine the relative 3D positions of the sensors and actuators connected to GPCs. A closed form approximate solution is derived using the technique of metric multidimensional scaling, which is further refined by minimizing a non-linear error function. Our formulation and solution account for the errors in localization, due to lack of temporal synchronization among different platforms. The performance limit for the sensor positions is analyzed with respect to the number of sensors and actuators as well as their geometry. Simulation results are reported together with a discussion of the practical issues in a real-time system.
The Siberian Traps volcanism is widely considered the main cause of the end-Permian mass extinction, the greatest biological crisis in the Earth history. While the extinction is interpreted as ...catastrophic and sudden with estimates of duration of approximately 35–40 thousand years from marine strata in South China, various lines of evidence have emerged for a more complex, prolonged, and diachronous extinction pattern. We present here the results of a multidisciplinary study of the Permian-Triassic continental transition in the Kuznetsk Basin, Russia. The region is proximal to the Siberian Traps LIP and the detrimental effects of the flood basalt volcanism in the Kuznetsk Basin may have been of similar scale as in the main area of the Siberian Traps distribution (Tunguska and Taymyr regions). Whereas earlier work has placed the Permian-Triassic boundary position between the coal-bearing Tailugan Formation and the volcanoclastic Maltsev Formation, here we revised the traditional model using three independent methods: radioisotopic CA-IDTIMS U-Pb zircon ages, δ13Corg isotope values and paleomagnetic proxies. The regional extinction of the humid-dominated forest flora (cordaites) and the aridity-induced biotic turnover in the Kuznetsk Basin occurred 820 kyr earlier than the end-Permian extinction event recorded in South China at 251.94 Ma. The biota in Kuznetsk Basin at the turnover subsequently diversified (with some exceptions) across the Permian-Triassic transition.
By compiling a large taxonomic database, we find that marine and terrestrial biotic diversity in Siberia progressively increased from the beginning of the Permian up to the middle Roadian (early Guadalupian global glacial event). After that time, the diversity at the species and generic level progressively and slowly declined towards the aforementioned latest Changhsingian (252.76 Ma) biotic turnover. Starting from this time, the biota rapidly diversified in the latest Changhsingian and Early-Middle Triassic. We suggest that the Permian-Triassic mass extinction mostly occurred in the tropics and subtropics due to the strong climatic warming, which was relatively low in late Changhsingian and gradually but quickly extends in the latest Changhsingian to an abnormally high temperature and extremely low oxygenated water in the oceans that was deadly for most marine animals. The warm climate shift poleward during Permian-Triassic transition in the middle-high latitudes caused the replacement (turnover) of the humid-related biotas by the dry climate-related and more diverse communities, which continued to expand throughout the Triassic in both marine and terrestrial habitats. The pattern of the Permian-Triassic event in both marine and terrestrial habitats was more intricate in terms of extinction, turnover, and diversity of biota within the different climatic zones and environmental habitats than has been generally considered.
•Permian-Triassic transition in Kuznetsk Basin (Russia) constrained with CA-IDTIMS dates.•Regional biota evolutionary turnover in the region occurs 820 kyr earlier than in South China.•The biota in Kuznetsk Basin diversified across the Permian-Triassic transition.•Permian-Triassic extinction mostly occurs in the tropics due to the strong climatic warming.•Siberian basalts as a cause of the extinction at the P-T boundary remain questionable.
