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Author Borja, E.F.; Garay, I.; Vidotto, F. url  doi
openurl 
  Title Learning about Quantum Gravity with a Couple of Nodes Type Journal Article
  Year 2012 Publication Symmetry Integrability and Geometry-Methods and Applications Abbreviated Journal (down) Symmetry Integr. Geom.  
  Volume 8 Issue Pages 015 - 44pp  
  Keywords discrete gravity; canonical quantization; spinors; spinfoam; quantum cosmology  
  Abstract Loop Quantum Gravity provides a natural truncation of the infinite degrees of freedom of gravity, obtained by studying the theory on a given finite graph. We review this procedure and we present the construction of the canonical theory on a simple graph, formed by only two nodes. We review the U(N) framework, which provides a powerful tool for the canonical study of this model, and a formulation of the system based on spinors. We consider also the covariant theory, which permits to derive the model from a more complex formulation, paying special attention to the cosmological interpretation of the theory.  
  Address [Borja, Enrique F.; Garay, Inaki] Univ Erlangen Nurnberg, Inst Theoret Phys 3, D-91058 Erlangen, Germany, Email: efborja@theorie3.physik.uni-erlangen.de;  
  Corporate Author Thesis  
  Publisher Natl Acad Sci Ukraine, Inst Math Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1815-0659 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000303831400001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1018  
Permanent link to this record
 

 
Author Aliaga, R.J.; Guirao, A.J. url  doi
openurl 
  Title On the preserved extremal structure of Lipschitz-free spaces Type Journal Article
  Year 2019 Publication Studia Mathematica Abbreviated Journal (down) Studia Math.  
  Volume 245 Issue 1 Pages 1-14  
  Keywords concave space; extremal structure; Lipschitz-free space; Lipschitz function; metric alignment; preserved extreme point  
  Abstract We characterize preserved extreme points of the unit ball of Lipschitz-free spaces F (X) in terms of simple geometric conditions on the underlying metric space (X, d). Namely, the preserved extreme points are the elementary molecules corresponding to pairs of points p, q in X such that the triangle inequality d (p, q) <= d (p, r) + d (q, r) is uniformly strict for r away from p, q. For compact X, this condition reduces to the triangle inequality being strict. As a consequence, we give an affirmative answer to a conjecture of N. Weaver that compact spaces are concave if and only if they have no triple of metrically aligned points, and we show that all extreme points are preserved for several classes of compact metric spaces X, including Holder and countable compacta.  
  Address [Aliaga, Ramon J.; Guirao, Antonio J.] Univ Politecn Valencia, Inst Univ Matemat Pura & Aplicada, Camino Vera S-N, E-46022 Valencia, Spain, Email: raalva@upvnet.upv.es;  
  Corporate Author Thesis  
  Publisher Polish Acad Sciences Inst Mathematics-Impan Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0039-3223 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000446980500001 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 3753  
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Author Gomez-Cadenas, J.J.; Benlloch-Rodriguez, J.M.; Ferrario, P. doi  openurl
  Title Application of scintillating properties of liquid xenon and silicon photomultiplier technology to medical imaging Type Journal Article
  Year 2016 Publication Spectrochimica Acta Part B Abbreviated Journal (down) Spectroc. Acta Pt. B  
  Volume 118 Issue Pages 6-13  
  Keywords PET; TOF; Liquid xenon; Energy resolution; High sensitivity; Coincidence resolution time (CRT); SiPMs  
  Abstract We describe a new positron emission time-of-flight apparatus using liquid xenon. The detector is based in a liquid xenon scintillating cell. The cell shape and dimensions can be optimized depending on the intended application. In its simplest form, the liquid xenon scintillating cell is a box in which two faces are covered by silicon photomultipliers and the others by a reflecting material such as Teflon. It is a compact, homogenous and highly efficient detector which shares many of the desirable properties of monolithic crystals, with the added advantage of high yield and fast scintillation offered by liquid xenon. Our initial studies suggest that good energy and spatial resolution comparable with that achieved by lutetium oxyorthosilicate crystals can be obtained with a detector based in liquid xenon scintillating cells. In addition, the system can potentially achieve an excellent coincidence resolving time of better than 100 ps.  
  Address [Gomez-Cadenas, J. J.; Benlloch-Rodriguez, J. M.; Ferrario, Paola] Univ Valencia, CSIC, IFIC, E-46003 Valencia, Spain, Email: gomez@mail.cern.ch  
  Corporate Author Thesis  
  Publisher Pergamon-Elsevier Science Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0584-8547 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000374073300002 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 2631  
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Author Conde, D.; Castillo, F.L.; Escobar, C.; García, C.; Garcia Navarro, J.E.; Sanz, V.; Zaldívar, B.; Curto, J.J.; Marsal, S.; Torta, J.M. doi  openurl
  Title Forecasting Geomagnetic Storm Disturbances and Their Uncertainties Using Deep Learning Type Journal Article
  Year 2023 Publication Space Weather Abbreviated Journal (down) Space Weather  
  Volume 21 Issue 11 Pages e2023SW003474 - 27pp  
  Keywords geomagnetic storms; deep learning; forecasting; SYM-H; uncertainties; hyper-parameter optimization  
  Abstract Severe space weather produced by disturbed conditions on the Sun results in harmful effects both for humans in space and in high-latitude flights, and for technological systems such as spacecraft or communications. Also, geomagnetically induced currents (GICs) flowing on long ground-based conductors, such as power networks, potentially threaten critical infrastructures on Earth. The first step in developing an alarm system against GICs is to forecast them. This is a challenging task given the highly non-linear dependencies of the response of the magnetosphere to these perturbations. In the last few years, modern machine-learning models have shown to be very good at predicting magnetic activity indices. However, such complex models are on the one hand difficult to tune, and on the other hand they are known to bring along potentially large prediction uncertainties which are generally difficult to estimate. In this work we aim at predicting the SYM-H index characterizing geomagnetic storms multiple-hour ahead, using public interplanetary magnetic field (IMF) data from the Sun-Earth L1 Lagrange point and SYM-H data. We implement a type of machine-learning model called long short-term memory (LSTM) network. Our scope is to estimate the prediction uncertainties coming from a deep-learning model in the context of forecasting the SYM-H index. These uncertainties will be essential to set reliable alarm thresholds. The resulting uncertainties turn out to be sizable at the critical stages of the geomagnetic storms. Our methodology includes as well an efficient optimization of important hyper-parameters of the LSTM network and robustness tests.  
  Address [Conde, D.; Escobar, C.; Garcia, C.; Garcia, J. E.; Sanz, V.; Zaldivar, B.] Univ Valencia, CSIC, Ctr Mixto, Inst Fis Corpuscular IFIC, Valencia, Spain, Email: Daniel.Conde@ific.uv.es  
  Corporate Author Thesis  
  Publisher Amer Geophysical Union Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes WOS:001104189700001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5804  
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Author SCiMMA and SNEWS Collaborations (Baxter, A.L. et al); Colomer, M. doi  openurl
  Title Collaborative experience between scientific software projects using Agile Scrum development Type Journal Article
  Year 2022 Publication Software-Practice & Experience Abbreviated Journal (down) Softw.-Pract. Exp.  
  Volume 52 Issue Pages 2077-2096  
  Keywords Agile; cyberinfrastructure; multimessenger astrophysics; scientific computing; software development  
  Abstract Developing sustainable software for the scientific community requires expertise in software engineering and domain science. This can be challenging due to the unique needs of scientific software, the insufficient resources for software engineering practices in the scientific community, and the complexity of developing for evolving scientific contexts. While open-source software can partially address these concerns, it can introduce complicating dependencies and delay development. These issues can be reduced if scientists and software developers collaborate. We present a case study wherein scientists from the SuperNova Early Warning System collaborated with software developers from the Scalable Cyberinfrastructure for Multi-Messenger Astrophysics project. The collaboration addressed the difficulties of open-source software development, but presented additional risks to each team. For the scientists, there was a concern of relying on external systems and lacking control in the development process. For the developers, there was a risk in supporting a user-group while maintaining core development. These issues were mitigated by creating a second Agile Scrum framework in parallel with the developers' ongoing Agile Scrum process. This Agile collaboration promoted communication, ensured that the scientists had an active role in development, and allowed the developers to evaluate and implement the scientists' software requirements. The collaboration provided benefits for each group: the scientists actuated their development by using an existing platform, and the developers utilized the scientists' use-case to improve their systems. This case study suggests that scientists and software developers can avoid scientific computing issues by collaborating and that Agile Scrum methods can address emergent concerns.  
  Address [Baxter, Amanda L.; Clark, Michael; Kopec, Abigail; Lang, Rafael F.; Li, Shengchao; Linvill, Mark W.; Milisavljevic, Danny; Weil, Kathryn E.] Purdue Univ, Dept Phys & Astron, W Lafayette, IN 47907 USA, Email: adepoian@purdue.edu;  
  Corporate Author Thesis  
  Publisher Wiley Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0038-0644 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000830363800001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5305  
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Author Esteve, R.; Toledo, J.F.; Herrero, V.; Simon, A.; Monrabal, F.; Alvarez, V.; Rodriguez, J.; Querol, M.; Ballester, F. doi  openurl
  Title The Event Detection System in the NEXT-White Detector Type Journal Article
  Year 2021 Publication Sensors Abbreviated Journal (down) Sensors  
  Volume 21 Issue 2 Pages 673 - 18pp  
  Keywords xenon TPC; trigger concepts; data acquisition circuits; FPGA  
  Abstract This article describes the event detection system of the NEXT-White detector, a 5 kg high pressure xenon TPC with electroluminescent amplification, located in the Laboratorio Subterraneo de Canfranc (LSC), Spain. The detector is based on a plane of photomultipliers (PMTs) for energy measurements and a silicon photomultiplier (SiPM) tracking plane for offline topological event filtering. The event detection system, based on the SRS-ATCA data acquisition system developed in the framework of the CERN RD51 collaboration, has been designed to detect multiple events based on online PMT signal energy measurements and a coincidence-detection algorithm. Implemented on FPGA, the system has been successfully running and evolving during NEXT-White operation. The event detection system brings some relevant and new functionalities in the field. A distributed double event processor has been implemented to detect simultaneously two different types of events thus allowing simultaneous calibration and physics runs. This special feature provides constant monitoring of the detector conditions, being especially relevant to the lifetime and geometrical map computations which are needed to correct high-energy physics events. Other features, like primary scintillation event rejection, or a double buffer associated with the type of event being searched, help reduce the unnecessary data throughput thus minimizing dead time and improving trigger efficiency.  
  Address [Esteve Bosch, Raul; Toledo Alarcon, Jose F.; Herrero Bosch, Vicente; Alvarez Puerta, Vicente; Rodriguez Samaniego, Javier; Ballester Merelo, Francisco] Univ Politecn Valencia, CSIC, Inst Instrumentac Imagen Mol I3M, Ctr Mixto, Camino Vera S-N, Valencia 46022, Spain, Email: rauesbos@eln.upv.es;  
  Corporate Author Thesis  
  Publisher Mdpi Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000611719600001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4693  
Permanent link to this record
 

 
Author Real, D.; Calvo, D.; Diaz, A.; Salesa Greus, F.; Sanchez Losa, A. doi  openurl
  Title A Narrow Optical Pulse Emitter Based on LED: NOPELED Type Journal Article
  Year 2022 Publication Sensors Abbreviated Journal (down) Sensors  
  Volume 22 Issue 19 Pages 7683 - 15pp  
  Keywords short optical pulse; optical instrumentation  
  Abstract Light sources emitting short pulses are needed in many particle physics experiments using optical sensors as they can replicate the light produced by the particles being detected and are also an important calibration and test element. This work presents NOPELED, a light source based on LEDs emitting short optical pulses with typical rise times of less than 3 ns and Full Width at Half Maximum lower than 7 ns. The emission wavelength depends on the model of LED used. Several LED models have been characterized in the range from 405 to 532 nm, although NOPELED can work with LED emitting wavelengths outside of that region. While the wavelength is fixed for a given LED model, the intensity and the frequency of the optical pulse can be controlled. NOPELED, which also has low cost and simple operation, can be operated remotely, making it appropriate for either different physics experiments needing in-place light sources such as astrophysical neutrino detectors using photo-multipliers or positron emission tomography devices using scintillation counters, or, beyond physics, applications needing short pulses of light such as protein fluorescence or chemodetection of heavy metals.  
  Address [Real, Diego; Calvo, David; Salesa Greus, Francisco; Sanchez Losa, Agustin] Univ Valencia, IFIC Inst Fis Corpuscular, CSIC, C Catedrat Jose Beltran 2, Paterna 46980, Spain, Email: real@ific.uv.es;  
  Corporate Author Thesis  
  Publisher Mdpi Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000867935300001 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 5381  
Permanent link to this record
 

 
Author Real, D.; Calvo, D.; Zornoza, J.D.; Manzaneda, M.; Gozzini, R.; Ricolfe-Viala, C.; Lajara, R.; Albiol, F. doi  openurl
  Title Fast Coincidence Filter for Silicon Photomultiplier Dark Count Rate Rejection Type Journal Article
  Year 2024 Publication Sensors Abbreviated Journal (down) Sensors  
  Volume 24 Issue 7 Pages 2084 - 12pp  
  Keywords time-to-digital converters; neutrino telescopes; silicon photomultipliers; dark noise rate filtering  
  Abstract Silicon Photomultipliers find applications across various fields. One potential Silicon Photomultiplier application domain is neutrino telescopes, where they may enhance the angular resolution. However, the elevated dark count rate associated with Silicon Photomultipliers represents a significant challenge to their widespread utilization. To address this issue, it is proposed to use Silicon Photomultipliers and Photomultiplier Tubes together. The Photomultiplier Tube signals serve as a trigger to mitigate the dark count rate, thereby preventing undue saturation of the available bandwidth. This paper presents an investigation into a fast and resource-efficient method for filtering the Silicon Photomultiplier dark count rate. A low-resource and fast coincident filter has been developed, which removes the Silicon Photomultiplier dark count rate by using as a trigger the Photomultiplier Tube input signals. The architecture of the coincidence filter, together with the first results obtained, which validate the effectiveness of this method, is presented.  
  Address [Real, Diego; Calvo, David; Zornoza, Juan de Dios; Manzaneda, Mario; Gozzini, Rebecca; Albiol, Francisco] CSIC Univ Valencia, IFIC Inst Fis Corpuscular, C Catedrat Jose Beltran 2, Paterna 46980, Spain, Email: real@ific.uv.es;  
  Corporate Author Thesis  
  Publisher Mdpi Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes WOS:001201226600001 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 6063  
Permanent link to this record
 

 
Author Martin-Luna, P.; Esperante, D.; Prieto, A.F.; Fuster-Martinez, N.; Rivas, I.G.; Gimeno, B.; Ginestar, D.; Gonzalez-Iglesias, D.; Hueso, J.L.; Llosa, G.; Martinez-Reviriego, P.; Meneses-Felipe, A.; Riera, J.; Regueiro, P.V.; Hueso-Gonzalez, F. doi  openurl
  Title Simulation of electron transport and secondary emission in a photomultiplier tube and validation Type Journal Article
  Year 2024 Publication Sensors and Actuators A-Physical Abbreviated Journal (down) Sens. Actuator A-Phys.  
  Volume 365 Issue Pages 114859 - 10pp  
  Keywords Photomultiplier tube; Photodetector; Proton therapy; Monte Carlo simulation; Measurement  
  Abstract The electron amplification and transport within a photomultiplier tube (PMT) has been investigated by developing an in-house Monte Carlo simulation code. The secondary electron emission in the dynodes is implemented via an effective electron model and the Modified Vaughan's model, whereas the transport is computed with the Boris leapfrog algorithm. The PMT gain, rise time and transit time have been studied as a function of supply voltage and external magnetostatic field. A good agreement with experimental measurements using a Hamamatsu R13408-100 PMT was obtained. The simulations have been conducted following different treatments of the underlying geometry: three-dimensional, two-dimensional and intermediate (2.5D). The validity of these approaches is compared. The developed framework will help in understanding the behavior of PMTs under highly intense and irregular illumination or varying external magnetic fields, as in the case of prompt gamma-ray measurements during pencil-beam proton therapy; and aid in optimizing the design of voltage dividers with behavioral circuit models.  
  Address [Martin-Luna, Pablo; Esperante, Daniel; Fuster-Martinez, Nuria; Gimeno, Benito; Gonzalez-Iglesias, Daniel; Llosa, Gabriela; Martinez-Reviriego, Pablo; Meneses-Felipe, Alba; Hueso-Gonzalez, Fernando] CSIC UV, Inst Fis Corpuscular IFIC, C Catedrat Jose Beltran 2, Paterna 46980, Spain, Email: pablo.martin@uv.es  
  Corporate Author Thesis  
  Publisher Elsevier Science Sa Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0924-4247 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:001131902700001 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 5876  
Permanent link to this record
 

 
Author Garcia Navarro, J.E.; Fernandez-Prieto, L.M.; Villaseñor, A.; Sanz, V.; Ammirati, J.B.; Diaz Suarez, E.A.; Garcia, C. doi  openurl
  Title Performance of Deep Learning Pickers in Routine Network Processing Applications Type Journal Article
  Year 2022 Publication Seismological Research Letters Abbreviated Journal (down) Seismol. Res. Lett.  
  Volume 93 Issue Pages 2529-2542  
  Keywords  
  Abstract Picking arrival times of P and S phases is a fundamental and time‐consuming task for the routine processing of seismic data acquired by permanent and temporary networks. A large number of automatic pickers have been developed, but to perform well they often require the tuning of multiple parameters to adapt them to each dataset. Despite the great advance in techniques, some problems remain, such as the difficulty to accurately pick S waves and earthquake recordings with a low signal‐to‐noise ratio. Recently, phase pickers based on deep learning (DL) have shown great potential for event identification and arrival‐time picking. However, the general adoption of these methods for the routine processing of monitoring networks has been held back by factors such as the availability of well‐documented software, computational resources, and a gap in knowledge of these methods. In this study, we evaluate recent available DL pickers for earthquake data, comparing the performance of several neural network architectures. We test the selected pickers using three datasets with different characteristics. We found that the analyzed DL pickers (generalized phase detection, PhaseNet, and EQTransformer) perform well in the three tested cases. They are very efficient at ignoring large‐amplitude transient noise and at picking S waves, a task that is often difficult even for experienced analysts. Nevertheless, the performance of the analyzed DL pickers varies widely in terms of sensitivity and false discovery rate, with some pickers missing a significant percentage of true picks and others producing a large number of false positives. There are also variations in run time between DL pickers, with some of them requiring significant resources to process large datasets. In spite of these drawbacks, we show that DL pickers can be used efficiently to process large seismic datasets and obtain results comparable or better than current standard procedures.  
  Address  
  Corporate Author Thesis  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5500  
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