Search results for "missing"
showing 10 items of 174 documents
Observation of Higgs Boson Decays to WW* with Dilepton and Missing Transverse Momentum Events in the ATLAS Detector
2015
This thesis presents a wide range of studies that go from energy reconstruction at the cell level in TileCal performance reconstruction of the E/T measurement in ATLAS, and finishing with the discovery of the Higgs boson decaying into a pair of W bosons. The reconstruction of the energy, as well as the time, in the TileCal cells is provided by the OF algorithm. These measurements are the inputs for object reconstruction algorithms which base their logic on the signal over noise ratio. In this light, the determination of the cell noise is crucial for an accurate event recons- truction in ATLAS. The impact of the TileCal noise constants has been evaluated through the performance of topocluste…
Monitoring and data quality assessment of the ATLAS liquid argon calorimeter
2014
The liquid argon calorimeter is a key component of the ATLAS detector installed at the CERN Large Hadron Collider. The primary purpose of this calorimeter is the measurement of electron and photon kinematic properties. It also provides a crucial input for measuring jets and missing transverse momentum. An advanced data monitoring procedure was designed to quickly identify issues that would affect detector performance and ensure that only the best quality data are used for physics analysis. This article presents the validation procedure developed during the 2011 and 2012 LHC data-taking periods, in which more than 98% of the proton-proton luminosity recorded by ATLAS at a centre-of-mass ener…
CLUSTERING INCOMPLETE SPECTRAL DATA WITH ROBUST METHODS
2018
Abstract. Missing value imputation is a common approach for preprocessing incomplete data sets. In case of data clustering, imputation methods may cause unexpected bias because they may change the underlying structure of the data. In order to avoid prior imputation of missing values the computational operations must be projected on the available data values. In this paper, we apply a robust nan-K-spatmed algorithm to the clustering problem on hyperspectral image data. Robust statistics, such as multivariate medians, are more insensitive to outliers than classical statistics relying on the Gaussian assumptions. They are, however, computationally more intractable due to the lack of closed-for…
Impact of the terrestrial reference frame on the determination of the celestial reference frame.
2022
Currently three up-to-date Terrestrial Reference Frames (TRF) are available, the ITRF2014 from IGN, the DTRF2014 from DGFI-TUM, and JTRF2014 from JPL. All use the identical input data of space-geodetic station positions and Earth orientation parameters, but the concept of combining these data is fundamentally different. The IGN approach is based on the combination of technique solutions, while the DGFI is combining the normal equation systems. Both yield in reference epoch coordinates and velocities for a global set of stations. JPL uses a Kalman filter approach, realizing a TRF through weekly time series of geocentric coordinates. As the determination of the CRF is not independent of the T…
Search for pair production of first or second generation leptoquarks in proton-proton collisions at sqrt(s)=7 TeV using the ATLAS detector at the LHC
2011
This paper describes searches for the pair production of first or second generation scalar leptoquarks using 35 pb−1 of proton-proton collision data recorded by the ATLAS detector at √s=7 TeV. Leptoquarks are searched in events with two oppositely-charged muons or electrons and at least two jets, and in events with one muon or electron, missing transverse momentum and at least two jets. After event selection, the observed yields are consistent with the predicted backgrounds. Leptoquark production is excluded at the 95% CL for masses MLQ<376 (319) GeV and MLQ<422 (362) GeV for first and second generation scalar leptoquarks, respectively, when assuming the branching fraction of a leptoquark…
Toolbox for Distance Estimation and Cluster Validation on Data With Missing Values
2022
Missing data are unavoidable in the real-world application of unsupervised machine learning, and their nonoptimal processing may decrease the quality of data-driven models. Imputation is a common remedy for missing values, but directly estimating expected distances have also emerged. Because treatment of missing values is rarely considered in clustering related tasks and distance metrics have a central role both in clustering and cluster validation, we developed a new toolbox that provides a wide range of algorithms for data preprocessing, distance estimation, clustering, and cluster validation in the presence of missing values. All these are core elements in any comprehensive cluster analy…
Feasibility of the Allergy Questionnaire for Athletes (AQUA © ) in pediatric age
2018
A burden of respiratory and allergic symptoms up to almost 60% has been observed in young and adult athletes, influencing physical performances1 . The Allergy Questionnaire for Athletes (AQUA©) is a validated screening tool for the prediction of the atopic status in adult athletes2 ; it was recently tested in Belgian young elite athletes (12-14 years old)3 , but its actual feasibility and suitability for children and adolescent was not evaluated. Indeed, there is evidence that children are prone to employ "satisficing" response strategies, answering every question positively/negatively, or simply not answering4 . Therefore, the present cross-sectional survey was carried out to assess feasib…
P-1294 - Utility of the world health organization disability assessment schedule II in schizophrenia
2012
Aim The World Health Organization Disability Assessment Schedule II (WHODAS II) was developed for assessing disability. This study provides data on the validity and utility of the Spanish version of the WHODAS II in a large sample of patients with schizophrenia. Methods The sample included 352 patients with a schizophrenia spectrum disorder. They completed a comprehensive assessment battery including measures of psychopathology, functionality and quality-of-life. A sub-sample of 36 patients was retested after six months to assess its temporal stability. Results Participation in society (6.3%) and Life activities (4.0%) were the domains with the highest percentage of missing data. The intern…
"Postfit yields Y(4S)" of "Search for $B^{+}\to K^{+}\nu\bar{\nu}$ decays using an inclusive tagging method at Belle II"
2022
Yields in on-resonance data and as predicted by the simultaneous fit to the on- and off-resonance data, corresponding to an integrated luminosity of 63 and 9 fb$^{−1}$, respectively. The predicted yields are shown individually for charged and neutral B-meson decays and the five continuum background categories. The leftmost three bins belong to the first control region (CR1) with BDT$_{2} \in [0.93; 0.95]$ and the other nine bins correspond to the signal region (SR), three for each range of BDT$_{2} \in [0.95; 0.97; 0.99; 1.0]$. Each set of three bins is defined by $p_{T}(K^{+}) \in [0.5; 2.0; 2.4; 3.5] \rm{GeV}/c^{2}$.
"Postfit yields off-resonance" of "Search for $B^{+}\to K^{+}\nu\bar{\nu}$ decays using an inclusive tagging method at Belle II"
2022
Yields in off-resonance data and as predicted by the simultaneous fit to the on- and off-resonance data, corresponding to an integrated luminosity of 63 and 9 fb$^{−1}$, respectively. The predicted yields are shown individually for the five continuum background categories. The leftmost three bins belong to the third control region (CR3) with BDT$_{2} \in [0.93; 0.95]$ and the other nine bins correspond to the second control region (CR2), three for each range of BDT$_{2} \in [0.95; 0.97; 0.99; 1.0]$. Each set of three bins is defined by $p_{T}(K^{+}) \in [0.5; 2.0; 2.4; 3.5] \rm{GeV}/c^{2}$.