Oksana Shadura

Oksana Shadura
University of Nebraska at Lincoln | NU

Doctor of Philosophy

About

117
Publications
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4,913
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Publications

Publications (117)
Article
Full-text available
Full detector simulation was among the largest CPU consumers in all CERN experiment software stacks for the first two runs of the Large Hadron Collider. In the early 2010s, it was projected that simulation demands would scale linearly with increasing luminosity, with only partial compensation from increasing computing resources. The extension of fa...
Preprint
Full-text available
Full detector simulation was among the largest CPU consumer in all CERN experiment software stacks for the first two runs of the Large Hadron Collider (LHC). In the early 2010's, the projections were that simulation demands would scale linearly with luminosity increase, compensated only partially by an increase of computing resources. The extension...
Preprint
Full-text available
The high energy physics community is discussing where investment is needed to prepare software for the HL-LHC and its unprecedented challenges. The ROOT project is one of the central software players in high energy physics since decades. From its experience and expectations, the ROOT team has distilled a comprehensive set of areas that should see r...
Preprint
C++ Modules come in C++20 to fix the long-standing build scalability problems in the language. They provide an io-efficient, on-disk representation capable to reduce build times and peak memory usage. ROOT employs the C++ modules technology further in the ROOT dictionary system to improve its performance and reduce the memory footprint. ROOT with C...
Preprint
In mathematics and computer algebra, automatic differentiation (AD) is a set of techniques to evaluate the derivative of a function specified by a computer program. AD exploits the fact that every computer program, no matter how complicated, executes a sequence of elementary arithmetic operations (addition, subtraction, multiplication, division, et...
Preprint
We overview recent changes in the ROOT I/O system, increasing performance and enhancing it and improving its interaction with other data analysis ecosystems. Both the newly introduced compression algorithms, the much faster bulk I/O data path, and a few additional techniques have the potential to significantly to improve experiment's software perfo...
Article
Full-text available
The LHC’s Run3 will push the envelope on data-intensive workflows and, since at the lowest level this data is managed using the ROOT software framework, preparations for managing this data are starting already. At the beginning of LHC Run 1, all ROOT data was compressed with the ZLIB algorithm; since then, ROOT has added support for additional algo...
Article
Full-text available
Distinct HEP workflows have distinct I/O needs; while ROOT I/O excels at serializing complex C++ objects common to reconstruction, analysis workflows typically have simpler objects and can sustain higher event rates. To meet these workflows, we have developed a “bulk I/O” interface, allowing multiple events’ data to be returned per library call. Th...
Article
Full-text available
ROOT is a large code base with a complex set of build-time dependencies; there is a significant difference in compilation time between the “core” of ROOT and the full-fledged deployment. We present results on a “delayed build” for internal ROOT packages and external packages. This gives the ability to offer a “lightweight” core of ROOT, later exten...
Article
Full-text available
ROOT has several features which interact with libraries and require implicit header inclusion. This can be triggered by reading or writing data on disk, or user actions at the prompt. Often, the headers are immutable, and reparsing is redundant. C++ Modules are designed to minimize the reparsing of the same header content by providing an efficient...
Article
Full-text available
In mathematics and computer algebra, automatic differentiation (AD) is a set of techniques to evaluate the derivative of a function specified by a computer program. AD exploits the fact that every computer program, no matter how complicated, executes a sequence of elementary arithmetic operations (addition, subtraction, multiplication, division, et...
Article
Full-text available
C++ Modules, one of the new features of C++20, aim to fix the long-standing build scalability problems in the language. They provide an IOefficient, on-disk representation capable to reduce build times and peak memory usage. ROOT already employs the C++ modules technology in its dictionary system to improve performance and reduce the memory footpri...
Preprint
Full-text available
ROOT has several features which interact with libraries and require implicit header inclusion. This can be triggered by reading or writing data on disk, or user actions at the prompt. Often, the headers are immutable, and reparsing is redundant. C++ Modules are designed to minimize the reparsing of the same header content by providing an efficient...
Preprint
Full-text available
ROOT is a large code base with a complex set of build-time dependencies; there is a significant difference in compilation time between the "core" of ROOT and the full-fledged deployment. We present results on a "delayed build" for internal ROOT packages and external packages. This gives the ability to offer a "lightweight" core of ROOT, later exten...
Preprint
The LHCs Run3 will push the envelope on data-intensive workflows and, since at the lowest level this data is managed using the ROOT software framework, preparations for managing this data are starting already. At the beginning of LHC Run 1, all ROOT data was compressed with the ZLIB algorithm; since then, ROOT has added support for additional algor...
Preprint
Distinct HEP workflows have distinct I/O needs; while ROOT I/O excels at serializing complex C++ objects common to reconstruction, analysis workflows typically have simpler objects and can sustain higher event rates. To meet these workflows, we have developed a "bulk I/O" interface, allowing multiple events data to be returned per library call. Thi...
Article
Full-text available
The GeantV R & D approach is revisiting the standard particle transport simulation approach to be able to benefit from "Single Instruction, Multiple Data" (SIMD) computational architectures or extremely parallel systems like coprocessors and GPUs. The goal of this work is to develop a mechanism for optimizing the programs used for High-Energy Physi...
Article
Full-text available
The development of the GeantV Electromagnetic (EM) physics package has evolved following two necessary paths towards code modernization. A first phase required the revision of the main electromagnetic physics models and their implementation. The main objectives were to improve their accuracy, extend them to the new high-energy frontier posed by the...
Article
Full-text available
SIMD acceleration can potentially boost by factors the application throughput. Achieving efficient SIMD vectorization for scalar code with complex data flow and branching logic, goes however way beyond breaking some loop dependencies and relying on the compiler. Since the refactoring effort scales with the number of lines of code, it is important t...
Article
Full-text available
The ROOT software framework is foundational for the HEP ecosystem, providing multiple capabilities such as I/O, a C++ interpreter, GUI, and math libraries. It uses object-oriented concepts and build-time components to layer between them. We believe that a new layering formalism will benefit the ROOT user community. We present the modularization str...
Article
Full-text available
Foundational software libraries such as ROOT are under intense pressure to avoid software regression, including performance regressions. Continuous performance benchmarking, as a part of continuous integration and other code quality testing, is an industry best-practice to understand how the performance of a software product evolves. We present a f...
Article
Full-text available
ROOT is a data analysis framework broadly used in and outside of High Energy Physics (HEP). Since HEP software frameworks always strive for performance improvements, ROOT was extended with experimental support of runtime C++ Modules. C++ Modules are designed to improve the performance of C++ code parsing. C++ Modules offers a promising way to impro...
Article
The paper shows that high energy physics (FEV) and nuclear physics research are not possible without the use of large computing power and special software for data processing, modeling, and analysis. Combining the classic implementation of evolutionary algorithms with non-teacher machine learning creates a powerful approach that can effectively opt...
Preprint
Full-text available
ROOT is a core HEP framework which is used broadly in and outside HEP. As HEP software frameworks always strive for performance, ROOT was extended with experimental support for using C++ modules during runtime. C++ modules are designed in part to improve the performance of parsing C++. As ROOT is parsing and interpreting C++ during runtime, C++ mod...
Preprint
Full-text available
The ROOT software framework is foundational for the HEP ecosystem, providing capabilities such as IO, a C++ interpreter, GUI, and math libraries. It uses object-oriented concepts and build-time components to layer between them. We believe additional layering formalisms will benefit ROOT and its users. We present the modularization strategy for ROOT...
Preprint
Full-text available
Foundational software libraries such as ROOT are under intense pressure to avoid software regression, including performance regressions. Continuous performance benchmarking, as a part of continuous integration and other code quality testing, is an industry best-practice to understand how the performance of a software product evolves over time. We p...
Article
Full-text available
In the fall 2016, GeantV went through a thorough community evaluation of the project status and of its strategy for sharing the R&D results with the LHC experiments and with the HEP simulation community in general. Following this discussion, GeantV has engaged onto an ambitious 2-year road-path aiming to deliver a beta version that has most of the...
Article
We report measurements of the inclusive J/ψ yield and average transverse momentum as a function of charged-particle pseudorapidity density dNch/dη in p–Pb collisions at sNN=5.02TeV with ALICE at the LHC. The observables are normalised to their corresponding averages in non-single diffractive events. An increase of the normalised J/ψ yield with norm...
Article
Full-text available
This letter presents the first measurement of jet mass in Pb–Pb and p–Pb collisions at sNN=2.76 TeV and sNN=5.02 TeV, respectively. Both the jet energy and the jet mass are expected to be sensitive to jet quenching in the hot Quantum Chromodynamics (QCD) matter created in nuclear collisions at collider energies. Jets are reconstructed from charged...
Article
Full-text available
GeantV is a complex system based on the interaction of different modules needed for detector simulation, which include transport of particles in fields, physics models simulating their interactions with matter and a geometrical modeler library for describing the detector and locating the particles and computing the path length to the current volume...
Article
Full-text available
The recent progress in parallel hardware architectures with deeper vector pipelines or many-cores technologies brings opportunities for HEP experiments to take advantage of SIMD and SIMT computing models. Launched in 2013, the GeantV project studies performance gains in propagating multiple particles in parallel, improving instruction throughput an...
Article
Full-text available
An intensive R&D and programming effort is required to accomplish new challenges posed by future experimental high-energy particle physics (HEP) programs. The GeantV project aims to narrow the gap between the performance of the existing HEP detector simulation software and the ideal performance achievable, exploiting latest advances in computing te...
Article
Full-text available
In two-particle angular correlation measurements, jets give rise to a near-side peak, formed by particles associated to a higher-pT trigger particle. Measurements of these correlations as a function of pseudorapidity (Δη) and azimuthal (Δφ) differences are used to extract the centrality and pT dependence of the shape of the near-side peak in the pT...
Article
Full-text available
The measurement of two-particle angular correlations is a powerful tool to study jet quenching in a pT region inaccessible by direct jet identification. In these measurements pseudorapidity (Δη) and azimuthal (Δφ) differences are used to extract the shape of the near-side peak formed by particles associated with a higher pT trigger particle (1<pT,t...
Article
Full-text available
The production cross sections for prompt charmed mesons \(\mathrm{D^0}\), \(\mathrm{D^+}\), \(\mathrm{D^{*+}}\) and \(\mathrm{D_s^+}\) were measured at mid-rapidity in proton–proton collisions at a centre-of-mass energy \(\sqrt{s}=7~{\mathrm {TeV}}\) with the ALICE detector at the Large Hadron Collider (LHC). D mesons were reconstructed from their...
Article
Full-text available
Two-particle angular correlations were measured in pp collisions at s=7 TeV for pions, kaons, protons, and lambdas, for all particle/anti-particle combinations in the pair. Data for mesons exhibit an expected peak dominated by effects associated with mini-jets and are well reproduced by general purpose Monte Carlo generators. However, for baryon–ba...
Article
Full-text available
The production of beauty hadrons was measured via semi-leptonic decays at mid-rapidity with the ALICE detector at the LHC in the transverse momentum interval 1<pT< 8 GeV/c in minimum-bias p-Pb collisions at \( \sqrt{s_{\mathrm{NN}}}=5.02 \) TeV and in 1.3 < pT< 8 GeV/c in the 20% most central Pb-Pb collisions at \( \sqrt{s_{\mathrm{NN}}}=2.76 \) Te...
Article
Full-text available
The production of K*(892)0 and ϕ(1020) mesons in proton-proton (pp) and lead-lead (Pb-Pb) collisions at sNN=2.76TeV has been analyzed using a high luminosity data sample accumulated in 2011 with the ALICE detector at the Large Hadron Collider (LHC). Transverse momentum (pT) spectra have been measured for K*(892)0 and ϕ(1020) mesons via their hadron...
Article
Full-text available
We present the first azimuthally differential measurements of the pion source size relative to the second harmonic event plane in Pb-Pb collisions at a center-of-mass energy per nucleon-nucleon pair of sNN=2.76 TeV. The measurements have been performed in the centrality range 0%–50% and for pion pair transverse momenta 0.2<kT<0.7 GeV/c. We find tha...
Article
The transverse momentum distributions of the strange and double-strange hyperon resonances (Σ (1385) ±, Ξ (1530) ⁰) produced in p–Pb collisions at sNN=5.02 TeV were measured in the rapidity range - 0.5 < yCMS< 0 for event classes corresponding to different charged-particle multiplicity densities, ⟨ dNch/dηlab⟩. The mean transverse momentum values a...
Article
We present results on transverse momentum (pT) and rapidity (y) differential production cross sections, mean transverse momentum and mean transverse momentum square of inclusive J / ψ and ψ(2 S) at forward rapidity (2.5 < y< 4) as well as ψ(2 S) -to-J / ψ cross section ratios. These quantities are measured in pp collisions at center of mass energie...
Article
Full-text available
This is an addendum to the article JHEP11 (2015) 205 [1]. The figures 3 (right), 4 (right) and 5 are updated with published results on non-prompt J/ψ-meson production from the CMS collaboration [2]. Open image in new window
Article
Full-text available
The first study of ϕ-meson production in p–Pb collisions at forward and backward rapidity, at a nucleon–nucleon centre-of-mass energy sNN=5.02 TeV, has been performed with the ALICE apparatus at the LHC. The ϕ-mesons have been identified in the dimuon decay channel in the transverse momentum (pT) range 1<pT<7 GeV/c, both in the p-going (2.03<y<3.53...
Article
Full-text available
Electrons from heavy-flavour hadron decays (charm and beauty) were measured with the ALICE detector in Pb–Pb collisions at a centre-of-mass of energy . The transverse momentum ( ) differential production yields at mid-rapidity were used to calculate the nuclear modification factor in the interval GeV/c. The shows a strong suppression compared to bi...
Article
Full-text available
At sufficiently high temperature and energy density, nuclear matter undergoes a transition to a phase in which quarks and gluons are not confined: the quark–gluon plasma (QGP). Such an exotic state of strongly interacting quantum chromodynamics matter is produced in the laboratory in heavy nuclei high-energy collisions, where an enhanced production...
Article
Full-text available
We present the first measurement of the two-particle transverse momentum differential correlation function, P2≡⟨ΔpTΔpT⟩/⟨pT⟩2, in Pb-Pb collisions at sNN=2.76 TeV. Results for P2 are reported as a function of the relative pseudorapidity (Δη) and azimuthal angle (Δφ) between two particles for different collision centralities. The Δϕ dependence is fo...
Article
Full-text available
The azimuthal correlations of D mesons with charged particles were measured with the ALICE apparatus in pp collisions at \({\sqrt{s}}=7~\mathrm {TeV}\) and p–Pb collisions at \({\sqrt{{{s}}_{\scriptscriptstyle {\mathrm{NN}}}}}=5.02~\mathrm {TeV}\) at the Large Hadron Collider. \(\mathrm{D}^{0}\), \({\mathrm{D}^{+}}\), and \({\mathrm{D}^{*+}}\) meso...
Article
Full-text available
The production of muons from heavy-flavour hadron decays in p–Pb collisions at sNN=5.02 TeV was studied for 2<pT<16 GeV/c with the ALICE detector at the CERN LHC. The measurement was performed at forward (p-going direction) and backward (Pb-going direction) rapidity, in the ranges of rapidity in the centre-of-mass system (cms) 2.03<ycms<3.53 and −4...
Article
Full-text available
Particle identification is an important feature of the ALICE detector at the LHC. In particular, for particle identification via the time-of-flight technique, the precise determination of the event collision time represents an important ingredient of the quality of the measurement. In this paper, the different methods used for such a measurement in...
Article
Full-text available
The W and Z boson production was measured via the muonic decay channel in proton-lead collisions at sNN=5.02 TeV at the Large Hadron Collider with the ALICE detector. The measurement covers backward (−4.46 < ycms < −2.96) and forward (2.03 < ycms < 3.53) rapidity regions, corresponding to Pb-going and p-going directions, respectively. The Z-boson p...
Article
Full-text available
The inclusive J/ψ production has been studied in Pb–Pb and pp collisions at the centre-of-mass energy per nucleon pair , using the ALICE detector at the CERN LHC. The J/ψ meson is reconstructed, in the centre-of-mass rapidity interval and in the transverse-momentum range , via its decay to a muon pair. In this Letter, we present results on the incl...
Article
Full-text available
A detailed study of pseudorapidity densities and multiplicity distributions of primary charged particles produced in proton–proton collisions, at \(\sqrt{s} =\) 0.9, 2.36, 2.76, 7 and 8 TeV, in the pseudorapidity range \(|\eta |<2\), was carried out using the ALICE detector. Measurements were obtained for three event classes: inelastic, non-single...
Article
Full-text available
At sufficiently high temperature and energy density, nuclear matter undergoes a transition to a phasein which quarks and gluons are not confined: the Quark-Gluon Plasma (QGP) [1]. Such an extremestate of strongly-interacting QCD (Quantum Chromo-Dynamics) matter is produced in the laboratorywith high-energy collisions of heavy nuclei, where an enhan...
Conference Paper
Machine learning for complex multi-objective problems (MOP) can substantially speedup the discovery of solutions belonging to Pareto landscapes and improve Pareto front accuracy. Studying convergence speedup of multi-objective search on well-known benchmarks is an important step in the development of algorithms to optimize complex problems such as...
Article
Full-text available
Background: In the context of the investigation of the quark gluon plasma produced in heavy-ion collisions, hadrons containing heavy (charm or beauty) quarks play a special role for the characterization of the hot and dense medium created in the interaction. The measurement of the production of charm and beauty hadrons in proton–proton collisions,...
Article
Full-text available
We report the measurements of correlations between event-by-event fluctuations of amplitudes of anisotropic flow harmonics in nucleus-nucleus collisions, obtained for the first time using a new analysis method based on multiparticle cumulants in mixed harmonics. This novel method is robust against systematic biases originating from nonflow effects...
Article
Full-text available
We present measurements of two-particle correlations with neutral pion trigger particles of transverse momenta 8<pTtrig<16 GeV/c and associated charged particles of 0.5<pTassoc<10 GeV/c versus the azimuthal angle difference Δφ at midrapidity in pp and central Pb-Pb collisions at sNN=2.76 TeV with ALICE. The new measurements exploit associated charg...
Article
Full-text available
The GeantV project aims to research and develop the next-generation simulation software describing the passage of particles through matter. While the modern CPU architectures are being targeted first, resources such as GPGPU, Intel© Xeon Phi, Atom or ARM cannot be ignored anymore by HEP CPU-bound applications. The proof of concept GeantV prototype...
Article
Full-text available
The recent emergence of hardware architectures characterized by many-core or accelerated processors has opened new opportunities for concurrent programming models taking advantage of both SIMD and SIMT architectures. GeantV, a next generation detector simulation, has been designed to exploit both the vector capability of mainstream CPUs and multi-t...