scholarly journals A Unified Methodology for Heartbeats Detection in Seismocardiogram and Ballistocardiogram Signals

Computers ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 41
Author(s):  
Niccolò Mora ◽  
Federico Cocconcelli ◽  
Guido Matrella ◽  
Paolo Ciampolini
Keyword(s):  
Absolute Error ◽  
Average Sensitivity ◽  
Application Range ◽  
Significant Difference ◽  
Temporal Waveform ◽  
Unsupervised Approach ◽  
Single Dataset ◽  
Temporal Annotation ◽  
Fine Tune ◽  
Annotation Errors

This work presents a methodology to analyze and segment both seismocardiogram (SCG) and ballistocardiogram (BCG) signals in a unified fashion. An unsupervised approach is followed to extract a template of SCG/BCG heartbeats, which is then used to fine-tune temporal waveform annotation. Rigorous performance assessment is conducted in terms of sensitivity, precision, Root Mean Square Error (RMSE) and Mean Absolute Error (MAE) of annotation. The methodology is tested on four independent datasets, covering different measurement setups and time resolutions. A wide application range is therefore explored, which better characterizes the robustness and generality of the method with respect to a single dataset. Overall, sensitivity and precision scores are uniform across all datasets ( p > 0.05 from the Kruskal–Wallis test): the average sensitivity among datasets is 98.7%, with 98.2% precision. On the other hand, a slight yet significant difference in RMSE and MAE scores was found ( p < 0.01 ) in favor of datasets with higher sampling frequency. The best RMSE scores for SCG and BCG are 4.5 and 4.8 ms, respectively; similarly, the best MAE scores are 3.3 and 3.6 ms. The results were compared to relevant recent literature and are found to improve both detection performance and temporal annotation errors.

Validating the usefulness of sectorwise regression of visual field in the central 10°

2021 ◽  
pp. bjophthalmol-2020-317391
Author(s):  
Takashi Omoto ◽  
Hiroshi Murata ◽  
Yuri Fujino ◽  
Masato Matsuura ◽  
Takehiro Yamashita ◽  
...  
Keyword(s):  
Visual Field ◽  
Mean Absolute Error ◽  
Open Angle Glaucoma ◽  
Absolute Error ◽  
Open Angle ◽  
Clustering Method ◽  
Significant Difference ◽  
The Mean ◽  
Test Points

AimTo evaluate the usefulness of the application of the clustering method to the trend analysis (sectorwise regression) in comparison with the pointwise linear regression (PLR).MethodsThis study included 153 eyes of 101 patients with open-angle glaucoma. With PLR, the total deviation (TD) values of the 10th visual field (VF) were predicted using the shorter VF sequences (from first 3 to 9) by extrapolating TD values against time in a pointwise manner. Then, 68 test points were stratified into 29 sectors. In each sector, the mean of TD values was calculated and allocated to all test points belonging to the sector. Subsequently, the TD values of the 10th VF were predicted by extrapolating the allocated TD value against time in a pointwise manner. Similar analyses were conducted to predict the 11th–16th VFs using the first 10 VFs.ResultsWhen predicting the 10th VF using the shorter sequences, the mean absolute error (MAE) values were significantly smaller in the sectorwise regression than in PLR. When predicting from the 11th and 16th VFs using the first 10 VFs, the MAE values were significantly larger in the sectorwise regression than in PLR when predicting the 11th VF; however, no significant difference was observed with other VF predictions.ConclusionAccurate prediction was achieved using the sectorwise regression, in particular when a small number of VFs were used in the prediction. The accuracy of the sectorwise regression was not hampered in longer follow-up compared with PLR.

scholarly journals Effect of Stress Ratio and Notch on Fatigue Strength of Commercial Pure Titanium

2020 ◽  
Vol 321 ◽  
pp. 11012
Author(s):  
IWATA Toshiaki
Keyword(s):  
Fatigue Strength ◽  
Fatigue Limit ◽  
Pure Titanium ◽  
Longitudinal Direction ◽  
Structural Members ◽  
Application Range ◽  
Seawater Corrosion ◽  
Significant Difference ◽  
Safe Side ◽  
Cp Ti

Titanium alloys such as Ti-6Al-4V are widely used in the aerospace domain worldwide; consequently, they have been extensively investigated, and the accumulated data has facilitated their use in the construction of structural members. In contrast, commercial pure (CP) Ti, which is cheaper than Ti alloys is widely used in the general industry, especially in the marine domain in Japan because it exhibits superior seawater corrosion resistance and biocompatibility. However, CP titanium has a strong anisotropy and consists of an hcp crystal structure; therefore, the strength data are insufficient owing to its short use history as a structural material, and some of its mechanical material properties remain unclear. Herein, the effect of mean stress and stress concentration on the fatigue strength of CP Grade 2 titanium was evaluated for the application range expansion of CP titanium. The results indicated that the fatigue limit in the longitudinal direction was 80–84% that in the transverse direction for smooth specimens. However, no significant difference was noted in the fatigue limit in both the directions for notched specimens. Furthermore, it was noted that it is necessary to apply at least Sa-0.5Su line to design the safe side in CP Grade 2 titanium.

scholarly journals Criterion-Related Validity of Knee Joint-Position-Sense Measurement Using Image Capture and Isokinetic Dynamometry

2015 ◽  
Vol 24 (1) ◽  
Author(s):  
Nicola Relph ◽  
Lee Herrington
Keyword(s):  
Knee Joint ◽  
Knee Flexion ◽  
Cost Effective ◽  
Absolute Error ◽  
Knee Extension ◽  
Position Sense ◽  
Joint Position Sense ◽  
Joint Position ◽  
Image Capture ◽  
Significant Difference

Context: Clinicians require portable, valid, and cost-effective methods to monitor knee joint-position-sense (JPS) ability. Objective: To examine the criterion-related validity of image-capture JPS measures against an isokinetic-dynamometer (IKD) procedure. Design: Random crossover design providing a comparison of knee JPS measures from image capture and IKD procedures. Participants: 10 healthy participants, 5 female, age 28.0 ± 13.29 y, mass 60.3 ± 9.02 kg, height 1.65 ± 0.07 m, and 5 male, 29.6 ± 10.74 y, mass 73.6 ± 5.86 kg, height 1.75 ± 0.07 m. Main Outcome Measures: The dependent variables were absolute error scores (AES) provided by 2 knee directions (flexion and extension). The independent variables were the method (image capture and IKD). Results: There was no significant difference between clinical and IKD AED into knee-extension data (P = .263, r = 0.55). There was a significant difference between clinical and IKD AES into knee-flexion data (P = .016, r =.70). Conclusions: Analysis of photographic images to assess JPS measurements using knee flexion is valid against IKD techniques. However, photo-analysis measurements provided a lower error score using knee-extension data and thus may provide an optimal environment to produce maximal knee JPS acuity. Therefore, clinicians do not need expensive equipment to collect representative JPS ability.

Prediction Models for the Erector Spinae Muscle Cross-Sectional Area

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Celal Gungor ◽  
Ruoliang Tang ◽  
Richard F. Sesek ◽  
Kenneth Bo Foreman ◽  
Sean Gallagher ◽  
...  
Keyword(s):  
Prediction Models ◽  
Absolute Error ◽  
Cross Sectional Area ◽  
Erector Spinae ◽  
Low Back ◽  
Sectional Area ◽  
Cross Sectional ◽  
Erector Spinae Muscle ◽  
Significant Difference ◽  
Mri Scans

Accurate and reliable “individualized” low back erector spinae muscle (ESM) data are of importance to estimate its force producing capacity. Knowing the force producing capacity, along with spinal loading, enhances the understanding of low back injury mechanisms. The objective of this study was to build regression models to estimate the ESM cross-sectional area (CSA). Measurements were taken from axial-oblique magnetic resonance imaging (MRI) scans of a large historical population [54 females and 53 males at L3/L4, 50 females and 44 males at L4/L5, and 41 females and 35 males at L5/S1 levels]. Results suggest that an individual's ESM CSA can be accurately estimated based on his/her gender, height, and weight. Results further show that there is no significant difference between the measured and estimated ESM CSAs, and expected absolute error is less than 15%.

scholarly journals Positional differences in anticipation timing, reaction time and dynamic balance of American football players

2020 ◽  
Vol 24 (5) ◽  
pp. 227-239
Author(s):  
Halil İ. Ceylan ◽  
Ahmet R. Günay
Keyword(s):  
Reaction Time ◽  
Dynamic Balance ◽  
Absolute Error ◽  
American Football ◽  
Football Players ◽  
Balance Performance ◽  
Significant Difference ◽  
Visual Reaction ◽  
Test Result ◽  
Anterior Posterior

Purpose: The aim of this study was to compare the coinciding anticipation timing (CAT), reaction time and dynamic balance performances of American football players according to their playing positions. Material: Thirty-five American football players, who train at least 3 days a week, and compete in Universities Protected Football 1st League, participated in this study, voluntarily. The players were divided into two playing positions: offensive (17 players, mean age: 20.76 ± 1.30 years) and defensive (18 players, mean age: 21.94 ± 2.87 years). The CAT at different stimulus speeds (6 mph, 12 mph), reaction time (visual, auditory, mixed), and dynamic balance performance (anterior-posterior, medial-lateral, perimeter lenght) were measured in the laboratory environment. The CAT, reaction time, and dynamic balance performance of players were determined by Bassin Anticipation Timer, Newtest 1000, and Technobody Prokin-200, respectively. Results: The data obtained were analyzed in SPSS (20.0) program. Firstly, the raw data for CAT performance (6mph, 12 mph) were converted to absolute error score. According to Shapiro-Wilk test result, the all data showed normal distribution. Independent Sample t test was used to determine the differences between the two playing positions. In addition, the effect size between the two playing positions was calculated in parameters with showing significant differences, and Cohen’s d (1988) values were taken into account. Compared with the defensive players (20.15±3.81 ms), the absolute error scores at fast stimulus speeds (12 mph) of offensive players (17.45±3.48 ms) was found to be significantly lower (t(33) =-2.181, p=.036). The visual reaction time of offensive players (318.11± 17.47 ms) was significantly shorter than defensive players (340.58± 32.60 ms, t(26322) =-2.560, p=.017). In terms of dynamic balance parameters such as perimeter lenght, anterior-posterior, and medial-lateral, there was no statistically significant difference between the playing positions (p>0.05). Conclusions: Perceptual-cognitive characteristics such as CAT, and reaction time performance differ according to the playing positions, and this difference may be related to the physical, and cognitive demands required by their playing positions.

scholarly journals Comparison between refractive outcome of primary piggy back intraocular lens versus secondary lens iris claw lens in posterior microphthalmos

2018 ◽  
Author(s):  
Abdelhamid Elhofi ◽  
Hany Ahmed Helaly ◽  
Amr Said
Keyword(s):  
Intraocular Lens ◽  
Absolute Error ◽  
Refractive Outcome ◽  
Significant Difference ◽  
Manifest Refraction ◽  
Safety Parameters ◽  
Other Regarding ◽  
Posterior Microphthalmos ◽  
Piggyback Iol ◽  
Iris Claw

Abstract Purpose: to compare the refractive outcome of 2 different methods of intraocular lens implantation in cases of posterior microphthalmos, primary piggy back IOLs versus secondary iris claw lenses. Methods: This study was a retrospective interventional comparative study that included 60 eyes of 30 patients. The included patients had bilateral microphthalmos with high axial hyperopia and had undergone a lens based surgical procedure for hyperopia correction. The included patients were equally divided into two groups. The first group had undergone refractive lens exchange (RLE) with primary piggyback IOL implantation. The second group undergone RLE with maximum available IOL power implanted followed by a secondary implantation of Artisan iris-fixated IOL (Ophtec B.V., Groningen, The Netherlands). Results: The 2 groups were highly comparable to each other regarding the mean age, axial length (AL), manifest refraction (MR), and K readings. Postoperative, there was a statistically significant difference between the 2 groups regarding the manifest refraction spherical equivalent (MRSE), mean absolute error (MAE), and uncorrected distance visual acuity (UDVA). There was no significant difference between the 2 groups regarding the CDVA. At 36 months, 20 % and 73 % of eyes were within + 0.5 D of intended refraction at 36 months in 1ry piggy back and 2ry Artisan groups respectively. Fifty-three % and 93 % of eyes were within + 1.0 D of intended refraction at 36 months in 1ry piggy back and 2ry Artisan groups respectively (p = 0.001). Conclusion: secondary procedure with implantation of iris-fixated intraocular lens yielded very good results for treatment of axial hyperopia in cases of posterior microphthalmos. The primary piggyback IOL showed less satisfactory results with cases of under correction and the possible complication of inter-lenticular opacification. Both groups showed good safety parameters.

scholarly journals EVALUASI DATA CLIMATE HAZARDS GROUP INFRARED PRECIPITATION WITH STATION (CHIRPS) DENGAN DATA PEMBANDING AUTOMATIC WEATHER STATIONS (AWS) DALAM MENGESTIMASI CURAH HUJAN HARIAN DI PROVINSI PAPUA BARAT

2021 ◽  
Vol 10 (1) ◽  
pp. 64
Author(s):  
Budiyono Budiyono ◽  
Arif Faisol
Keyword(s):  
Pearson Correlation ◽  
Daily Rainfall ◽  
Absolute Error ◽  
Satellite Observation ◽  
Probability Of Detection ◽  
T Test ◽  
Data Recording ◽  
Significant Difference ◽  
West Papua ◽  
Weather Stations

This research aims to evaluate the CHIRPS data in estimating daily rainfall in West Papua compared with automatic weather stations (AWS) data recording. The data used in this research are daily CHIRPS data and AWS daily data recording 1996 to 2020 from AWS Rendani–Manokwari, AWS Jefman–Raja Ampat, AWS Torea–Fakfak, and AWS Kaimana–Kaimana. CHIRPS data were evaluated using the Point to Pixel method based on numerical and categorical parameters i.e., root mean square error (RMSE), mean error (ME), mean absolute error (MAE), Pearson correlation (r), probability of detection (POD), critical success index (CSI), and T-test. The research showed that CHIRPS had a significant difference to AWS data in estimating daily rainfall in West Papua based on a T-test. However CHIRPS has a moderate accuracy in estimating daily rainfall in West Papua with RMSE = 8.59 mm, ME=2.75 mm, and MAE = 5.15 mm and had a moderate positive correlation with AWS data with r= 0.43. Besides, CHIRPS has good accuracy in detecting rain events in West Papua indicated by a POD = 0.72 and CSI = 0.43. Therefore, CHIRPS data can be used as an alternative solution for providing rainfall data in West Papua.   Keywords:  satellite observation, rainfall predictor, point to pixel 

scholarly journals Precision orientation herbicide spraying against weeds in plastic-mulched fields of spring hybrid millet

2019 ◽  
pp. 837
Author(s):  
Meijun Guo ◽  
Xi-e Song ◽  
Jie Shen ◽  
Jianming Wang ◽  
Xiatong Zhao ◽  
...  
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Comprehensive Evaluation ◽  
Foxtail Millet ◽  
Good Option ◽  
Weed Species ◽  
Efficacy Evaluation ◽  
Application Range ◽  
Significant Difference ◽  
Herbicide Treatments

Foxtail millet (Setaria italic [L.] P. Beauv.) is an important food and fodder crop that is cultivated worldwide. However, weeds severely inhibit the growth of spring foxtail millet, and no suitable herbicide or method is available for weed control in foxtail millet fields. Field experiments were conducted to evaluate the efficacy of various herbicides and their safety toward hybrid foxtail millet, that is, ‘Zhangzagu 10’. The present study was conducted using seven herbicides applied by precision orientation spraying between plastic mulches in a foxtail millet field. All herbicide treatments exhibited no significant difference on foxtail millet shoot and root biomass. No difference in grain yield was observed among herbicide treatments, including MCPA (2-methyl-4-chlorophenoxyacetic acid), mesotrione, acetochlor, trifluralin, and pendimethalin, at the recommended dosage in field efficacy evaluation trial. For the same herbicide, the tendency of weed control increased with the increase in herbicide concentration. Following this finding, all herbicides applied at the highest dosage controlled weeds by 92.06% compared with the other treatments utilizing lower concentration. At the same concentration level, mesotrione controlled all weed populations was the highest observed among all herbicides, followed by prometryne and MCPA. Mesotrione controlled all weeds by at least 76.85%, exhibiting the highest weed injury among the herbicides and satisfying the requirement for weed species control. Finally, comprehensive analyses showed that mesotrione at 0.8 L ha-1, yielded the highest comprehensive evaluation value in foxtail millet field. Thus, this herbicide can be a good option in controlling weeds in foxtail millet field. This new model can aid in protecting hybrid ‘Zhangzagu 10’ foxtail millet seeds or seedlings against herbicide damage and is a good option in expanding the application range of herbicide in foxtail millet.

scholarly journals Performance Assessment of a Variable-Rate Fertilizer Applicator

2019 ◽  
Vol 11 (2) ◽  
pp. 25
Author(s):  
Ruixiu Sui
Keyword(s):  
Control System ◽  
Tap Water ◽  
Absolute Error ◽  
Application Rate ◽  
Actual Application ◽  
Application Rates ◽  
Significant Difference ◽  
Lower Variation ◽  
Spray Control ◽  
Fertilizer Solution

The objective of this study was to test the performance of a Field-IQ sprayer control system which was interfaced with a John Deere liquid fertilizer applicator. The sprayer control system includes Case IH FM-1000 display integrated with DGPS, Field-IQ spray control with full harness, flowmeter and auto-range valve, and the pump. Tap water was used to simulate the UAN 32% nitrogen fertilizer solution in the test. A total of 120 samples from 8 rows of the applicator in 5 application rates (34, 67, 101, 135, and 168 kg/ha) were collected, and the data were analyzed for application uniformity and application rate accuracy of the system. Results showed the greatest variation from the application rate baseline among the rows was 10.1% and occurred at a swath-end row with the lowest application rate of 34 kg/ha. The rows in the middle section of the swath had the lower variation than the rows at the two swath-ends. The application uniformity increased as the application rate increased. The absolute error of application rate ranged from 1.3% to 6.5% with an average of 3.76%. There was no significant difference between the selected application rate and actual application rate (p &gt; 0.8686).

scholarly journals Análise e Correlação da Distância Percorrida no Teste de Caminhada de Seis Minutos com a Distância Prevista por Meio de Três Equações de Referência

2017 ◽  
Vol 19 (1) ◽  
pp. 25
Author(s):  
Ivete Alonso Bredda Saad ◽  
Laís Bacchin de Oliveira ◽  
Eliana Pereira de Melo Costa ◽  
Mariana Borges de Oliveira ◽  
Bruna Scharlack Vian
Keyword(s):  
Mean Squared Error ◽  
Mean Absolute Error ◽  
Absolute Error ◽  
Work Capacity ◽  
Work Capacity Evaluation ◽  
Walk Distance ◽  
Squared Error ◽  
Significant Difference ◽  
Minute Walk Distance ◽  
Minute Walk

O teste de caminhada de seis minutos - TC6’- é amplamente utilizado para avaliação da capacidade física e do prognóstico de diversas doenças, em que a distância percorrida no TC6’ (DTC6’) é uma das principais variáveis para interpretá-lo. Vários estudos desenvolveram equações para obter a distância predita no TC6’ - DPTC6’, porém as equações de predição mais conhecidas na literatura foram desenvolvidas com indivíduos saudáveis. O objetivo deste estudo foi analisar e correlacionar a DTC6’com a DPTC6’ por meio das equações de Enright et al. e Iwama et al. em pacientes com doenças do aparelho respiratório e/ou cardiovascular e verificar o comportamento da variável idade entre as diferentes faixas etárias da população estudada. Foram analisados 350 testes realizados em indivíduos de 18 a 86 anos, separados em seis grupos por faixa etária. Calculou-se a correlação, o erro quadrático médio e erro absoluto médio para comparar DTC6’ com a DPTC6’ pelas equações. Observou-se correlação média positiva entre as DTC6’ e DPTC6’. Houve diferença estatisticamente significante (p<0.0001) entre as DTC6’ entre jovens e idosos. Os menores valores totais de erro quadrático médio e erro absoluto médio foram de Iwama et al. Concluiu-se que as três equações se correlacionam em intensidades parecidas com as distâncias percorridas. A variável idade interferiu nos resultados. A equação de Iwama et al. foi a que melhor previu a DTC6’ nos indivíduos em questão até os 50 anos de idade se assemelhando a equação de Enright e Sherrill nos grupos mais velhos. A equação de Troosters et al. superestimou a DTC6’ em todos os grupos etários.Palavras-chave: Doenças Respiratórias. Testes Respiratórios. Avaliação da Capacidade de Trabalho.AbstractThe six-minute walk test (6MWT) is widely used for evaluation of physical capacity and prognosis of various diseases and the six-minute walk distance (6MWD) is one of the main variable to interpret it. Several studies have developed equations to obtain the six-minute walk distance predicted values (6MWDP), however, the most known prediction equations in the literature were developed with healthy subjects. The aim of this study was to analyze and correlate the 6MWD to 6MWDP by three references equations for prediction, Enright et al. and Iwama et al. 350 tests performed were analyzed in patients aged18 to 86 years old, divided into six groups. Correlation, mean squared error and mean absolute error were calculated to compare the 6MWD to 6MWDP by the equations. There was a positive correlation between the average of 6MWD and 6MWDP. There was a significant difference (p <0.0001) in 6MWD between young and elderly people. The lowest total values of mean squared error and mean absolute error were from Iwama et al. It was concluded that the three predictive equations correlate in similar intensities with the distances walked. Iwamaet al.’s equation was the one that best predicts the 6MWD in groups with individuals up to 50 years old and was similar to Enright and Sherrill equation in older groups. Troosters et al. equation overestimated the 6MWD in all age groups.Keywords: Respiratory Tract Diseases. Breathing Tests. Work Capacity Evaluation.

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