Comparison of supervised learning statistical methods for classifying commercial beers and identifying patterns

In this study, 13 properties (alcohol-, real extract-, flavonoid-, anthocyanin, glucose, fructose, maltose, sucrose content, EBC [European Brewery Convention] and L*a*b* color, bitterness) of 21 beers (alcohol-free pale lagers, alcohol-free beer-based mixed drinks, beer-based mixed drinks, international lagers, wheat beers, stouts, fruit beers) were determined. In the first step, multiple factor analysis (MFA) was performed for the whole data and five clusters (target classes) were determined; then, a bootstrapping was applied to establish a balanced data so as every cluster should contain 100 samples and the total sample size is 500. In the second step, 12 supervised learning algorithms (random trees [RND], Quinlan's C4.5 decision tree algorithm [C4.5], Iterative Dichotomiser 3 algorithm [ID3], cost-sensitive decision tree algorithm [CSMC4], cost-sensitive classification tree [CSCRT], k-nearest neighbors algorithm [KNN], radial basis function [RBF], multilayer perceptron neural network [MLP], prototype nearest neighbor [PNN], linear discriminant analysis [LDA], naïve Bayes with continuous variables [NBC], partial least squares discriminant analysis [PLS-DA]) were applied to classify each brand into the target classes. Furthermore, several error rates were calculated: re-substitution error rate (RER), cross-validated error rate (CV), bootsrap error (BOOT), leaveone-out (LOO), and train-test error rate (TRAIN). The MFA could discriminate five groups, which can be characterized by some analytical parameters, and the other multivariate methods performed similarly. The methods can be discriminated best based on the BOOT, CV, and LOO. The best estimation methods are the C4.5, CSMC4, and CSCRT; these performed best along the flavonoid content and EBC color. It identified that the methods most sensitive to the properties are the NBC. The classification ability fluctuated greatly in the case of three properties (glucose, maltose, sucrose). A remarkable fluctuation has been experienced in the case of L*a*b* color parameters, flavonoid content, EBC color, and bitterness by NBC method

How to objectively determine the color of beer?

Beer color is an important sensory attribute, the first one that the consumer observes. There are two standard methods accepted for determining the color of these products, one related to the European Brewery Convention (EBC) and the other is the Standard Reference Method (SRM). Both methods are based on absorbance, but in case of the more and more popular fruit beers these methods give false result since these products appear in varied colors and have different spectra than regular beers. In this study 39 different types of beers were investigated, including fruit beers and beer based mixed drinks to compare their color in CIE 1976 L*a*b* color space, absorption-based colors and transmission spectra. DE*ab values of products with less than 5% EBC difference ranged from 4.5 to 17.4. There were magnitude differences in the transmission spectra of these products, fruit beers showed different tendencies due to the added fruit or fruit juice. The highest DE*ab value belonged to two traditional Weissbiers. Absorption-based methods are not able in many cases to differentiate between products which have nearly the same EBC or SRM color but visually are different. A multi-wavelength method would be reasonable to be developed for more objective and accurate beer color determination

Dipper-like variability of the Gaia alerted young star V555 Ori

V555 Ori is a T Tauri star, whose 1.5 mag brightening was published as a Gaia science alert in 2017. We carried out optical and near-infrared photometric, and optical spectroscopic observations to understand the light variations. The light curves show that V555 Ori was faint before 2017, entered a high state for about a year, and returned to the faint state by mid-2018. In addition to the long-term flux evolution, quasi-periodic brightness oscillations were also evident, with a period of about 5 days. At optical wavelengths both the long-term and short-term variations exhibited colourless changes, while in the near-infrared they were consistent with changing extinction. We explain the brightness variations as the consequence of changing extinction. The object has a low accretion rate whose variation in itself would not be enough to reproduce the optical flux changes. This behaviour makes V555 Ori similar to the pre-main sequence star AA Tau, where the light changes are interpreted as periodic eclipses of the star by a rotating inner disc warp. The brightness maximum of V555 Ori was a moderately obscured ($A_V$=2.3 mag) state, while the extinction in the low state was $A_V$=6.4 mag. We found that while the Gaia alert hinted at an accretion burst, V555 Ori is a standard dipper, similar to the prototype AA Tau. However, unlike in AA Tau, the periodic behaviour was also detectable in the faint phase, implying that the inner disc warp remained stable in both the high and low states of the system.Comment: Accepted to MNRA

Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV

Probing effective field theory operators in the associated production of top quarks with a Z boson in multilepton final states at root s=13 TeV

Peer reviewe

Measurements of Higgs boson production cross sections and couplings in the diphoton decay channel at root s=13 TeV

Measurements of Higgs boson production cross sections and couplings in events where the Higgs boson decays into a pair of photons are reported. Events are selected from a sample of proton-proton collisions at root s = 13TeV collected by the CMS detector at the LHC from 2016 to 2018, corresponding to an integrated luminosity of 137 fb(-1). Analysis categories enriched in Higgs boson events produced via gluon fusion, vector boson fusion, vector boson associated production, and production associated with top quarks are constructed. The total Higgs boson signal strength, relative to the standard model (SM) prediction, is measured to be 1.12 +/- 0.09. Other properties of the Higgs boson are measured, including SM signal strength modifiers, production cross sections, and its couplings to other particles. These include the most precise measurements of gluon fusion and vector boson fusion Higgs boson production in several different kinematic regions, the first measurement of Higgs boson production in association with a top quark pair in five regions of the Higgs boson transverse momentum, and an upper limit on the rate of Higgs boson production in association with a single top quark. All results are found to be in agreement with the SM expectations.Peer reviewe

Observation of tW production in the single-lepton channel in pp collisions at root s=13 TeV

A measurement of the cross section of the associated production of a single top quark and a W boson in final states with a muon or electron and jets in proton-proton collisions at root s = 13 TeV is presented. The data correspond to an integrated luminosity of 36 fb(-1) collected with the CMS detector at the CERN LHC in 2016. A boosted decision tree is used to separate the tW signal from the dominant t (t) over bar background, whilst the subleading W+jets and multijet backgrounds are constrained using data-based estimates. This result is the first observation of the tW process in final states containing a muon or electron and jets, with a significance exceeding 5 standard deviations. The cross section is determined to be 89 +/- 4 (stat) +/- 12 (syst) pb, consistent with the standard model.Peer reviewe

Measurements of the Electroweak Diboson Production Cross Sections in Proton-Proton Collisions at root s=5.02 TeV Using Leptonic Decays

The first measurements of diboson production cross sections in proton-proton interactions at a center-of-mass energy of 5.02 TeV are reported. They are based on data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 302 pb(-1). Events with two, three, or four charged light leptons (electrons or muons) in the final state are analyzed. The WW, WZ, and ZZ total cross sections are measured as sigma(WW) = 37:0(-5.2)(+5.5) (stat)(-2.6)(+2.7) (syst) pb, sigma(WZ) = 6.4(-2.1)(+2.5) (stat)(-0.3)(+0.5)(syst) pb, and sigma(ZZ) = 5.3(-2.1)(+2.5)(stat)(-0.4)(+0.5) (syst) pb. All measurements are in good agreement with theoretical calculations at combined next-to-next-to-leading order quantum chromodynamics and next-to-leading order electroweak accuracy

Search for lepton-flavor violating decays of the Higgs boson in the mu tau and e tau final states in proton-proton collisions at root s=13 TeV

A search is presented for lepton-flavor violating decays of the Higgs boson to mu t and et. The dataset corresponds to an integrated luminosity of 137 fb(-1) collected at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV. No significant excess has been found, and the results are interpreted in terms of upper limits on lepton-flavor violating branching fractions of the Higgs boson. The observed (expected) upper limits on the branching fractions are, respectively, B(H -> mu t) e tau) < 0.22(0.16)% at 95% confidence level.Peer reviewe