scholarly journals Gpu-Based Online Track Reconstruction for the Alice Tpc in Run 3 With Continuous Read-Out

2019 ◽  
Vol 214 ◽  
pp. 01050 ◽  
Author(s):  
David Rohr ◽  
Sergey Gorbunov ◽  
Schmidt Ole Marten ◽  
Ruben Shahoyan
Keyword(s):  
Data Compression ◽  
A Priori ◽  
Hardware Accelerators ◽  
Phase Identification ◽  
Track Reconstruction ◽  
Online Processing ◽  
The Status ◽  
Reconstruction Strategy ◽  
Time Projection ◽  
Online Reconstruction

In LHC Run 3, ALICE will increase the data taking rate significantly to 50 kHz continuous read-out of minimum bias Pb—Pb collisions. The reconstruction strategy of the online-offline computing upgrade foresees a first synchronous online reconstruction stage during data taking enabling detector calibration and data compression, and a posterior calibrated asynchronous reconstruction stage. Many new challenges arise, among them continuous TPC read-out, more overlapping collisions, no a priori knowledge of the primary vertex and of location-dependent calibration in the synchronous phase, identification of low-momentum looping tracks, and sophisticated raw data compression. The tracking algorithm for the Time Projection Chamber (TPC) will be based on a Cellular Automaton and the Kalman filter. The reconstruction shall run online, processing 50 times more collisions per second than today, while yielding results comparable to current offline reconstruction. Our TPC track finding leverages the potential of hardware accelerators via the OpenCL and CUDA APIs in a shared source code for CPUs and GPUs for both reconstruction stages. We give an overview of the status of Run 3 tracking including performance on processors and GPUs and achieved compression ratios.

scholarly journals GPU-based reconstruction and data compression at ALICE during LHC Run 3

2020 ◽  
Vol 245 ◽  
pp. 10005
Author(s):  
David Rohr
Keyword(s):  
Data Compression ◽  
Real Time ◽  
Tracking System ◽  
Radiation Detector ◽  
Data Rate ◽  
Transition Radiation Detector ◽  
Real Time Processing ◽  
The Status ◽  
Time Projection ◽  
Online Reconstruction

In LHC Run 3, ALICE will increase the data taking rate significantly to 50 kHz continuous read out of minimum bias Pb-Pb collisions. The reconstruction strategy of the online offline computing upgrade foresees a first synchronous online reconstruction stage during data taking enabling detector calibration, and a posterior calibrated asynchronous reconstruction stage. The significant increase in the data rate poses challenges for online and offline reconstruction as well as for data compression. Compared to Run 2, the online farm must process 50 times more events per second and achieve a higher data compression factor. ALICE will rely on GPUs to perform real time processing and data compression of the Time Projection Chamber (TPC) detector in real time, the biggest contributor to the data rate. With GPUs available in the online farm, we are evaluating their usage also for the full tracking chain during the asynchronous reconstruction for the silicon Inner Tracking System (ITS) and Transition Radiation Detector (TRD). The software is written in a generic way, such that it can also run on processors on the WLCG with the same reconstruction output. We give an overview of the status and the current performance of the reconstruction and the data compression implementations on the GPU for the TPC and for the global reconstruction.

Self and Selves

2017 ◽  
Author(s):  
Ralph C.S. Walker
Keyword(s):  
Personal Identity ◽  
Moral Philosophy ◽  
A Priori ◽  
The Status ◽  
The Subject ◽  
Synthetic A Priori

Kant is committed to the reality of a subject self, outside time but active in forming experience. Timeless activity is problematic, but that can be dealt with. But he holds that the subject of experience is not an object of experience, so nothing can be known about it; this raises a problem about the status of his own theory. But he ought to allow that we can know of its existence and activity, as preconditions of experience: the Critique allows that synthetic a priori truths can be known in this way. However, its identity conditions remain unknowable. Kant’s unity of apperception shares much with Locke’s continuity of consciousness, but does not determine the identity of a thing. Personal identity is bodily identity. Only Kant’s moral philosophy justifies recognizing other selves; it could warrant ascribing a similar status to animals.

Oxford Studies in Epistemology Volume 6

2019 ◽  
Keyword(s):  
Decision Theory ◽  
A Priori ◽  
Formal Epistemology ◽  
Ethics Of Belief ◽  
Naturalized Epistemology ◽  
New Developments ◽  
The Status ◽  
Important Field ◽  
Belief Justification

Oxford Studies in Epistemology is a biennial publication offering a regular snapshot of state-of-the-art work in this important field. Under the guidance of a distinguished editorial board composed of leading epistemologists in North America, Europe and Australasia, it publishes exemplary papers in epistemology, broadly construed. Topics within its purview include: (a) traditional epistemological questions concerning the nature of belief, justification, and knowledge, the status of skepticism, the nature of the a priori, etc.; (b) new developments in epistemology, including movements such as naturalized epistemology, feminist epistemology, social epistemology, and virtue epistemology, and approaches such as contextualism; (c) foundational questions in decision-theory; (d) confirmation theory and other branches of philosophy of science that bear on traditional issues in epistemology; (e) topics in the philosophy of perception relevant to epistemology; (f) topics in cognitive science, computer science, developmental, cognitive, and social psychology that bear directly on traditional epistemological questions; and (g) work that examines connections between epistemology and other branches of philosophy, including work on testimony, the ethics of belief, etc. Topics addressed in volume 6 include the nature of perceptual justification, intentionality, modal knowledge, credences, epistemic supererogation, epistemic and rational norms, expressivism, skepticism, and pragmatic encroachment. The various writers make use of a variety of different tools and insights, including those of formal epistemology and decision theory, as well as traditional philosophical analysis and argumentation.

scholarly journals A Compact Muon Tracker for Dynamic Tomography of Density Based on a Thin Time Projection Chamber with Micromegas Readout

Particles ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 333-342
Author(s):  
Ignacio Lázaro Roche
Keyword(s):  
Time Projection Chamber ◽  
Wide Field ◽  
Track Reconstruction ◽  
Long Term Stability ◽  
Societal Issues ◽  
Primary Signal ◽  
And Performance ◽  
Time Projection

Tomography based on cosmic muon absorption is a rising technique because of its versatility and its consolidation as a geophysics tool over the past decade. It allows us to address major societal issues such as long-term stability of natural and man-made large infrastructures or sustainable underwater management. Traditionally, muon trackers consist of hodoscopes or multilayer detectors. For applications with challenging available volumes or the wide field of view required, a thin time projection chamber (TPC) associated with a Micromegas readout plane can provide a good tradeoff between compactness and performance. This paper details the design of such a TPC aiming at maximizing primary signal and minimizing track reconstruction artifacts. The results of the measurements performed during a case study addressing the aforementioned applications are discussed. The current works lines and perspectives of the project are also presented.

Über Gewissen und Gewissheit

2016 ◽  
Vol 64 (4) ◽  
Author(s):  
Dina Emundts
Keyword(s):  
Immanuel Kant ◽  
A Priori ◽  
Categorical Imperative ◽  
Moral Principles ◽  
The Third ◽  
The Status

AbstractThis paper suggests an understanding of the concept of “Gewissen” (conscience) according to which Gewissen is best understood as a receptivity to moral principles that corresponds to certain moral feelings. In the first part of the paper this suggestion is spelled out and alternatives to it are discussed. As is shown in the second part, this suggestion goes back to the thought of Immanuel Kant, but it can be developed even if one does not follow Kant in his understanding of the categorical imperative as an a priori principle. However, if one does not follow Kant with respect to the status of the categorical imperative, there are some interesting consequences for our understanding of conscience and especially for our understanding of its relation to knowledge and certainty. These consequences are discussed in the third part of this paper.

Implementation of a new real time seismicity detector for the Mayotte crisis

2021 ◽  
Author(s):  
Jean-Marie Saurel ◽  
Lise Retailleau ◽  
Weiqiang Zhu ◽  
Simon Issartel ◽  
Claudio Satriano ◽  
...  
Keyword(s):  
Real Time ◽  
Volcanic Activity ◽  
A Priori ◽  
Processing System ◽  
Activity Level ◽  
Phase Identification ◽  
Real Time Processing ◽  
S Waves ◽  
Hypocentral Location ◽  
New Processing

<p>Seismology is one of the main techniques used to monitor volcanic activity worldwide. Seismicity analysis through several seismic sensor deployments has been used to monitor Mayotte volcano crisis since its beginning in May 2018. Because volcanic activity can evolve rapidly, efficient and accurate seismicity detectors are crucial to assess in real-time the activity level of the volcano and, if needed, to issue timely warnings.</p><p> </p><p><span>Traditional real-time seismic processing software, such as EarthWorm or SeisComP, use phase onset pickers followed by a phase association algorithm to declare an event and proceed with its location. Real-time phase pickers usually cannot identify whether the detected phase is a P or S arrival and this decision or assumption is made by the associator. The lack of S arrival has an obvious impact on the hypocentral location quality. S-phases can also help detection on small earthquakes where weak P-phases can be missed.</span></p><p> </p><p><span>We implemented the deep neural network-based method PhaseNet to identify in real-time seismic P and S waves on 3-component seismometers deployed on Mayotte island. We also built an interface to subsequently process PhaseNet results and send pick objects to EarthWorm. We use EarthWorm binder_ew associator module specifically tuned for PhaseNet </span><span><em>a priori</em></span><span> phase identification to detect and locate the events, which are finally archived in a SeisComP database. We implemented this innovative real-time processing system for the REVOSIMA (Reseau de surveillance Volcanologique et Sismologique de Mayotte) hosted at OVPF (Observatoire Volcanologique du Piton de la Fournaise). We assess the robustness of the algorithm by comparing the results to existing automatic and manually detected seismicity catalogs.</span></p><p> </p><p>We show that the existing SeisComP automatic system is outperformed by our new algorithm, both in number of earthquake detections and location reliability. Our implementation also detects more events than the daily manual data screening. While this promising new processing system was first applied to study the Mayotte seismicity, it can be used in any seismic active zone, of volcanic or tectonic origin. Indeed, it will be installed at Martinique volcanic and seismic observatory later this year.</p>

Grenzen und Möglichkeiten der (paepckeschen) Hermeneutik

2021 ◽  
pp. 395-428
Author(s):  
Philippe Forget
Keyword(s):  
Conceptual Framework ◽  
A Priori ◽  
Theory And Practice ◽  
Contrastive Analysis ◽  
The Status ◽  
Functional Orientation ◽  
Human Orientation ◽  
The Relationship

After the author explicates how his academic relationship to Paepcke began in the 1970s, he proceeds to discuss critically the latter’s reflections on language and translation. Latent contradictions in Paepcke’s conceptual framework and in his understanding of the relationship between theory and practice are brought to the fore. This conceptual tension shows that Paepcke’s understanding of and approach to dealing with texts is problematic. Using concrete examples, the author demonstrates that Paepcke did not rely on the text as the criterion for constituting meaning. Rather Paepcke relied on historically mediated conceptual constructs which were given the status of authoritative units of sense, and these units guided Paepcke in his process of establishing the meaning of the whole. The reason for this can be found in unreflected preliminary decisions that are seen as “a priori evidence.” This also explains why Paepcke’s real achievement lies in the contrastive analysis of comprehensive concepts – of traditionally rich concepts developed over the course of time (human orientation) as well as in rationalized contemporary language (functional orientation).

Physics and Ontology in Spinoza: The Enigmatic Response to Tschirnhaus

2020 ◽  
pp. 27-49
Author(s):  
Alexandre Matheron
Keyword(s):  
A Priori ◽  
Mathematical Physics ◽  
Physical Universe ◽  
The Status

What is Spinoza’s relationship to the mathematical physics that followed from the Galilean revolution? In this essay, Matheron reconstructs Spinoza’s response to his interlocutor, Tschirnhaus, regarding the status of the concept of extension in Spinoza’s philosophy and, in particular, its difference from Descartes’s concept of extension. But, as Maheron notes, Spinoza nonetheless encountered difficulties in his response to Tschirnhaus, namely, his need to reformulate his ontology of power by once again rewriting the opening of the Ethics as well as redefine the status of physics. The successive drafts of the Ethics show Spinoza working towards a clearer and more concise account of his ontology of power, which holds that God as absolutely infinite causal substance has the power to produce anything and everything that is conceivable without contradiction. But does it then follow that the laws of the physical universe are deducible a priori? Matheron investigates Spinoza’s attempts to address this question and concludes with a discussion of Spinoza’s relevance for more contemporary developments in science.

Williamson on the A Priori and the Analytic

2020 ◽  
pp. 78-85
Author(s):  
Paul Boghossian ◽  
Timothy Williamson
Keyword(s):  
A Priori ◽  
A Posteriori ◽  
The Status

This essay criticizes Williamson’s attempt, in his book, The Philosophy of Philosophy, to undermine the interest of the a priori–a posteriori distinction. Williamson’s argument turns on several large claims. The first is that experience often plays a role intermediate between evidential and merely enabling, and that this poses a difficulty for giving a theoretically satisfying account of the distinction. The second is that there are no constitutive understanding–assent links. Both of these claims are subjected to detailed scrutiny. In particular, it is argued that Williamson’s case of the deviant logician, Simon, fails to constitute an intelligible counterexample to the status of conjunction elimination as an understanding–assent link for ‘and’.

scholarly journals First Demonstration of a Pixelated Charge Readout for Single-Phase Liquid Argon Time Projection Chambers

Instruments ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 9 ◽  
Author(s):  
Jonathan Asaadi ◽  
Martin Auger ◽  
Antonio Ereditato ◽  
Damian Goeldi ◽  
Umut Kose ◽  
...  
Keyword(s):  
Single Phase ◽  
Signal To Noise Ratio ◽  
Liquid Argon ◽  
Track Reconstruction ◽  
3D Tracking ◽  
3D Space ◽  
Time Projection Chambers ◽  
Event Reconstruction ◽  
Phase Liquid ◽  
Time Projection

Traditional charge readout technologies of single-phase Liquid Argon Time projection Chambers (LArTPCs) based on projective wire readout introduce intrinsic ambiguities in event reconstruction. Combined with the slow response inherent in LArTPC detectors, reconstruction ambiguities have limited their performance, until now. Here, we present a proof of principle of a pixelated charge readout that enables the full 3D tracking capabilities of LArTPCs. We characterize the signal-to-noise ratio of charge readout chain to be about 14, and demonstrate track reconstruction on 3D space points produced by the pixel readout. This pixelated charge readout makes LArTPCs a viable option for high-multiplicity environments.

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