data group
Recently Published Documents


TOTAL DOCUMENTS

165
(FIVE YEARS 80)

H-INDEX

13
(FIVE YEARS 4)

Author(s):  
Anderson G. Costa ◽  
Eudócio R. O. da Silva ◽  
Murilo M. de Barros ◽  
Jonatthan A. Fagundes

ABSTRACT The quality and price of coffee drinks can be affected by contamination with impurities during roasting and grinding. Methods that enable quality control of marketed products are important to meet the standards required by consumers and the industry. The purpose of this study was to estimate the percentage of impurities contained in coffee using textural and colorimetric descriptors obtained from digital images. Arabica coffee beans (Coffea arabica L.) at 100% purity were subjected to roasting and grinding processes, and the initially pure ground coffee was gradually contaminated with impurities. Digital images were collected from coffee samples with 0, 10, 30, 50, and 70% impurities. From the images, textural descriptors of the histograms (mean, standard deviation, entropy, uniformity, and third moment) and colorimetric descriptors (RGB color space and HSI color space) were obtained. The principal component regression (PCR) method was applied to the data group of textural and colorimetric descriptors for the development of linear models to estimate coffee impurities. The selected models for the textural descriptors data group and the colorimetric descriptors data group were composed of two and three principal components, respectively. The model from the colorimetric descriptors showed a greater capacity to estimate the percentage of impurities in coffee when compared to the model from the textural descriptors.


2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Yejin Kim ◽  
Sir-yeon Hong ◽  
Seo-yeon Kim ◽  
Yoo-min Kim ◽  
Ji-Hee Sung ◽  
...  

Abstract Background To compare obstetric and neonatal outcomes in twin pregnancies with or without gestational diabetes mellitus (GDM) before and after changes in GDM diagnostic criteria. Methods This was a retrospective cohort study of 1,764 twin pregnancies including 130 women with GDM (GDM group) and 1,634 women without GDM (non-GDM group). Patients with pregestational diabetes, unknown GDM status, and fetal death at < 24 gestational weeks were excluded. Obstetric and neonatal outcomes were compared between the two groups by two periods: period 1 (1995–2005) and period 2 (2005–2018) when National Diabetes Data Group criteria and Carpenter and Coustan criteria were used for diagnosis of GDM, respectively. Results The incidence of GDM in twin pregnancies increased from 4.0% in period 1 to 9.3% in period 2. Composite obstetric complications rate was significantly higher in the GDM group than that in the non-GDM group during period 1 (72.0% vs. 45.5%, P = 0.009). However, it became comparable during period 2 (60.0% vs. 57.4%, P = 0.601). Interaction between GDM and period indicated a significant differential effect of GDM by period on the rate of composite obstetric complications. The rate of composite neonatal complications was similar between the two groups during both periods. The interaction between GDM and period was not significant. Conclusion After changes of GDM diagnostic criteria, the incidence of GDM increased more than twice, and the rate of composite obstetric complications decreased, but the rate of composite neonatal complications did not change significantly.


2022 ◽  
Vol 11 (1) ◽  
pp. e3811124347
Author(s):  
Camilla Azevedo Silva Magalhães ◽  
Daniele Marano Rocha ◽  
Maria Elisabeth Lopes Moreira

Objetivos: Avaliar as divergências metodológicas entre os estudos que analisaram a associação entre o diabetes mellitus gestacional e a prematuridade. Métodos: A seleção dos artigos foi realizada entre outubro de 2020 e janeiro de 2021 nas bases de dados PubMed, Biblioteca Virtual em Saúde (Lilacs/Bireme/BVS Brasil), Embase e Scopus. Foram utilizados os seguintes descritores: “Gestational Diabetes Mellitus” and “Prematurity” que foram modificados de acordo com as regras de indexação de cada base de dados. Não houve restrição no período de publicação e idioma. Foram selecionados 12 estudos, sendo dois transversais, cinco coortes, quatro casos-controle e um ensaio clínico. Resultados: A maioria dos estudos utilizou o critério do National Diabetes Data Group para diagnóstico do diabetes mellitus gestacional. Dos estudos selecionados, seis observaram associação entre diabetes mellitus gestacional e a prematuridade. Conclusão: Além do impacto da multifatoriedade causal da prematuridade, os estudos que não encontraram associação entre diabetes mellitus gestacional e prematuridade apresentaram diferenças metodológicas, principalmente no que tange a definição, o rastreamento e o diagnóstico de diabetes mellitus gestacional podendo acarretar resultados díspares.


2021 ◽  
Vol 5 (2) ◽  
pp. 85-93
Author(s):  
Arifan Dwi Maulana ◽  
Indra Gita Anugrah

Clustering is an algorithm in a decision support system that functions to organize an object into groups of data. In the clustering process, of course, a cluster centre is needed by the desired data group. However, the clustering process has a problem. Related research states that the results of k-means clustering can influence the selection of cluster centre points. Random selection of cluster centre points can result in different clustering results in the same data group. Not only on k-means, but k-medoids also have the same problem. So that to produce a good cluster, you must start by choosing the right cluster centre. To solve this problem, the Simple Additive Weighting method is used to select the centre point of the cluster. Simple Additive Weighting selects the centre point of the cluster by adding and summarizing the dataset. The summation is done by giving weight to each criterion and each criterion has its alternative value. From this weighted addition, the final value will be obtained. From the sum of SAW, then one of the objects with the highest and lowest values ​​can be taken to serve as the centre of the cluster.


2021 ◽  
Author(s):  
◽  
Alan J. Taylor

<p>The performances of observers in auditory experiments are likely to be affected by extraneous noise from physiological or neurological sources and also by decision noise. Attempts have been made to measure the characteristics of this noise, in particular its level relative to that of masking noise provided by the experimenter. This study investigated an alternative approach, a method of analysis which seeks to reduce the effects of extraneous noise on measures derived from experimental data. Group-Operating-Characteristic (GOC) analysis was described by Watson (1963) and investigated by Boven (1976). Boven distinguished between common and unique noise. GOC analysis seeks to reduce the effects of unique noise. In the analysis, ratings of the same stimulus on different occasions are sunned. The cumulative frequency distributions of the resulting variable define a GOC curve. This curve is analogous to an ROC curve, but since the effects of unique noise tend to be averaged out during the summation, the GOC is less influenced by extraneous noise. The amount of improvement depends on the relative variance of the unique and common noise (k). Higher levels of unique noise lead to greater improvement. In this study four frequency discrimination experiments were carried out with pigeons as observers, using a three-key operant procedure. In other experiments, computer-simulated observers were used. The first two pigeon experiments, and the simulations, were based on known distributions of common noise. The ROCs for the constructed distributions provided a standard with which the GOC curve could be compared. In all cases the analysis led to improvements in the measures of performance and increased the match of the experimental results and the ideal ROC. The amount of improvement, as well as reflecting the level of unique noise, depended on the number of response categories. With smaller numbers of categories, improvement was reduced and k was underestimated. Since the pigeon observers made only "yes" or "no" responses, the results for the pigeon experiments were compared with the results of simulations with known distributions in order to obtain more accurate estimates of k. The third and fourth pigeon experiments involved frequency discrimination tasks with a standard of 450 Hz and comparison frequencies of 500, 600, 700, 800 and 900 Hz, and 650 Hz, respectively. With the multiple comparison frequencies the results were very variable. This was due to the small number of trials for each frequency and the small number of replications. The results obtained with one comparison frequency were more orderly but, like those of the previous experiment, were impossible to distinguish from those which would be expected if there was no common noise. A final set of experiments was based on a hardware simulation. Signals first used in the fourth pigeon experiment were processed by a system made up of a filter, a zero-axis crossing detector and a simulated observer. The results of these experiments were compatible with the possibility that the amount of unique noise in the pigeon experiments overwhelmed any evidence of common noise.</p>


2021 ◽  
Author(s):  
◽  
Alan J. Taylor

<p>The performances of observers in auditory experiments are likely to be affected by extraneous noise from physiological or neurological sources and also by decision noise. Attempts have been made to measure the characteristics of this noise, in particular its level relative to that of masking noise provided by the experimenter. This study investigated an alternative approach, a method of analysis which seeks to reduce the effects of extraneous noise on measures derived from experimental data. Group-Operating-Characteristic (GOC) analysis was described by Watson (1963) and investigated by Boven (1976). Boven distinguished between common and unique noise. GOC analysis seeks to reduce the effects of unique noise. In the analysis, ratings of the same stimulus on different occasions are sunned. The cumulative frequency distributions of the resulting variable define a GOC curve. This curve is analogous to an ROC curve, but since the effects of unique noise tend to be averaged out during the summation, the GOC is less influenced by extraneous noise. The amount of improvement depends on the relative variance of the unique and common noise (k). Higher levels of unique noise lead to greater improvement. In this study four frequency discrimination experiments were carried out with pigeons as observers, using a three-key operant procedure. In other experiments, computer-simulated observers were used. The first two pigeon experiments, and the simulations, were based on known distributions of common noise. The ROCs for the constructed distributions provided a standard with which the GOC curve could be compared. In all cases the analysis led to improvements in the measures of performance and increased the match of the experimental results and the ideal ROC. The amount of improvement, as well as reflecting the level of unique noise, depended on the number of response categories. With smaller numbers of categories, improvement was reduced and k was underestimated. Since the pigeon observers made only "yes" or "no" responses, the results for the pigeon experiments were compared with the results of simulations with known distributions in order to obtain more accurate estimates of k. The third and fourth pigeon experiments involved frequency discrimination tasks with a standard of 450 Hz and comparison frequencies of 500, 600, 700, 800 and 900 Hz, and 650 Hz, respectively. With the multiple comparison frequencies the results were very variable. This was due to the small number of trials for each frequency and the small number of replications. The results obtained with one comparison frequency were more orderly but, like those of the previous experiment, were impossible to distinguish from those which would be expected if there was no common noise. A final set of experiments was based on a hardware simulation. Signals first used in the fourth pigeon experiment were processed by a system made up of a filter, a zero-axis crossing detector and a simulated observer. The results of these experiments were compatible with the possibility that the amount of unique noise in the pigeon experiments overwhelmed any evidence of common noise.</p>


2021 ◽  
Author(s):  
Jawaher Abdulaziz Hamad Al-Juraywi

The present study investigated pragmatic transfer in the refusals of advanced Saudi learners of English as a foreign language (SEFL) in terms of the frequency and content of the emantic formulas, and whether their refusals correspond more to those of Saudi native speakers of Arabic (NSA) or native speakers of English (NSE). A total of 45 female subjects participated in the study and were divided into three groups: advanced SEFL as the target group (n = 15), NSA as a baseline data group (n = 15), and NSE as a baseline data group (n = 15). The study employed a mixed-method data collection approach consisting of a Discourse Completion Test (DCT) and semi-structured interviews. The collected data were analyzed quantitatively and qualitatively using the chi-square test and descriptive statistics. The results of the study revealed that pragmatic transfer was evident in the refusals of the SEFL group in both the frequency and content of semantic formulas. Moreover, the SEFL group’s realization of the speech act of refusal corresponded more to the NSA group than the NSE group. The analysis revealed that the SEFL group’s use of the direct refusal strategies, indirect refusal strategies, and adjuncts to refusals either resembled or approximated the NSA group’s use of the strategies to refuse all of the four stimulus types: requests, invitations, offers, and suggestions. Both the SEFL and NSA groups used the direct refusal strategies in a similar pattern; they used the direct strategies significantly less with interlocutors of a lower and higher social status, and significantly more with interlocutors of an equal social status. Furthermore, the content of the semantic formulas used by the SEFL group corresponded more to the content of the semantic formulas used by the NSA group in terms of the degree of specificity and the choice of the type of specific excuses. The SEFL group significantly approximated the NSA group’s use of both specific and unspecific excuses; they used three categories of specific excuses in a similar frequency: family, health, and personal preferences or needs.


2021 ◽  
pp. 1-85
Author(s):  
Jawaher Abdulaziz Hamad Al-Juraywi

The present study investigated pragmatic transfer in the refusals of advanced Saudi learners of English as a foreign language (SEFL) in terms of the frequency and content of the emantic formulas, and whether their refusals correspond more to those of Saudi native speakers of Arabic (NSA) or native speakers of English (NSE). A total of 45 female subjects participated in the study and were divided into three groups: advanced SEFL as the target group (n = 15), NSA as a baseline data group (n = 15), and NSE as a baseline data group (n = 15). The study employed a mixed-method data collection approach consisting of a Discourse Completion Test (DCT) and semi-structured interviews. The collected data were analyzed quantitatively and qualitatively using the chi-square test and descriptive statistics. The results of the study revealed that pragmatic transfer was evident in the refusals of the SEFL group in both the frequency and content of semantic formulas. Moreover, the SEFL group’s realization of the speech act of refusal corresponded more to the NSA group than the NSE group. The analysis revealed that the SEFL group’s use of the direct refusal strategies, indirect refusal strategies, and adjuncts to refusals either resembled or approximated the NSA group’s use of the strategies to refuse all of the four stimulus types: requests, invitations, offers, and suggestions. Both the SEFL and NSA groups used the direct refusal strategies in a similar pattern; they used the direct strategies significantly less with interlocutors of a lower and higher social status, and significantly more with interlocutors of an equal social status. Furthermore, the content of the semantic formulas used by the SEFL group corresponded more to the content of the semantic formulas used by the NSA group in terms of the degree of specificity and the choice of the type of specific excuses. The SEFL group significantly approximated the NSA group’s use of both specific and unspecific excuses; they used three categories of specific excuses in a similar frequency: family, health, and personal preferences or needs.


Author(s):  
Manfred Daum ◽  
Detlev Gotta

The most precise values of the mass of the negatively charged pion have been determined from several measurements of X-ray wavelengths for transitions in pionic atoms at PSI. The Particle Data Group gives the average m_{\pi^-}mπ− = (139.570 61 \pm± 0.000 24) MeV/c^22.


Author(s):  
Manfred Daum ◽  
Peter-R. Kettle

The most precise value for the pion mass was determined from a precision measurement at PSI of the muon momentum in pion decay at rest, \pi^+ \rightarrow \mu^+ + \nu_{\mu}π+→μ++νμ. The result is m_{\pi^+} = 139.570\,21(14)mπ+=139.57021(14)~MeV/c^22. This value is more precise, however, in agreement with the recent compilation of the Particle Data Group for m_{\pi^-}mπ−. The agreement of m_{\pi^+}mπ+ with the recent measurement. This yields a new quantitative measure of CPT invariance in the pion sector: (m_{\pi^+} - m_{\pi^-})/m_{\pi}(\mbox{av}) = (-2.9 \pm 2.0)\cdot 10^{-6}(mπ+−mπ−)/mπ(av)=(−2.9±2.0)⋅10−6, an improvement by two orders of magnitude.


Sign in / Sign up

Export Citation Format

Share Document