Optimal Margin Computation for At-Speed Test

2008 ◽  
Author(s):  
Jinjun Xiong ◽  
Vladimir Zolotov ◽  
Chandu Visweswariah ◽  
Peter A. Habitz
Keyword(s):  
Speed Test

scholarly journals Accuracy Improvement of Stator Inductance Identification Method Based on Low-Frequency Current Injection for Three-Level NPC Inverter-Fed IM Drives in Locked-Rotor Standstill Condition

Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 488
Author(s):  
Yerganat Khojakhan ◽  
Kyoung-Min Choo ◽  
Junsin Yi ◽  
Chung-Yuen Won
Keyword(s):  
Induction Motor ◽  
Low Frequency ◽  
Current Injection ◽  
Heavy Load ◽  
Injection Test ◽  
Low Speed ◽  
Injection Speed ◽  
Speed Test ◽  
Identification Method ◽  
Drive Systems

In this paper, a stator inductance identification process is proposed. The process is based on a three-level neutral-point-clamped (NPC) inverter-fed induction motor (IM) drive with a standstill condition. Previously, a low-speed alternating current (AC) injection test for stator inductance identification was proposed to overcome practical problems in conventional identification methods for three-level NPC inverter-based IM drives. However, the low-speed AC injection test-based identification method has some problems if a heavy load or mechanical brake is connected, as these can forcibly bring the rotor to a standstill during parameter identification. Since this low-speed testing-based identification assumes the motor torque is considerably lower in low-speed operations, some inaccuracy is inevitable in this kind of standstill condition. In this paper, the proposed current injection speed generator is based on the previously studied low-speed test-based stator inductance identification method, but the proposed approach gives more accurate estimates under the aforementioned standstill conditions. The proposed method regulates the speed for sinusoidal low-frequency AC injection on the basis of the instantaneous reactive and air-gap active power ratio. This proposed stator inductance identification method is more accurate than conventional fixed low-frequency AC signal injection identification method for three-level NPC inverter-fed IM drive systems with a locked-rotor standstill condition. The proposed method’s accuracy and reliability were verified by simulation and experiment using an 18.5 kW induction motor.

scholarly journals Cognitive, physical and disability trajectories in community-dwelling elderly people

2021 ◽  
Author(s):  
Ottavia Eleonora Ferraro ◽  
Antonio Guaita ◽  
Simona Villani
Keyword(s):  
Physical Function ◽  
Cumulative Incidence ◽  
Female Gender ◽  
Community Dwelling ◽  
Study Cohort ◽  
Carrier Status ◽  
Speed Test ◽  
Health Trajectories ◽  
Severe Group ◽  
Incidence Of Dementia

Abstract Backgrounds and aims Health trajectories in aging, rather than single time-point assessments, could be early indicators of the onset of conditions such as dementia. The aim of this study was to identify different aging trajectories and to investigate their influence on the cumulative incidence of dementia. Methods We evaluated data referring to 993 elders from the InveCe.Ab study cohort. All subjects were free from dementia at baseline and re-assessed on at least one other occasion thereafter. Cognitive function was assessed using the Mini-Mental State Examination (MMSE), physical function using the Walking Speed Test (WST), and disability on the basis of the Activities of Daily Living (ADL) score. To describe the different courses of the three outcomes combined, the Group-Based Trajectory Model (GBTM) method was applied. We looked for differences in age, gender, education, ApoE-e4 carrier status and obesity, and then investigated the influence of the observed trajectories on the incidence of dementia. Results Three trajectories were identified: a “good” scenario was observed in 703 (70.2%) individuals, who showed substantially stable cognitive and physical function and no disability; an “intermediate” scenario in 248 subjects (25.5%), who recorded a longer walking time, lower MMSE score, and a one-point higher ADL score; and a “severe” scenario in 42 elders (4.3%), who recorded declines in all the outcomes. Female gender, obesity and low education were most represented in the “severe” group. ApoE-e4 carrier status showed no difference between groups. The estimated cumulative incidence of dementia was higher in the “severe” (37%) than in the “intermediate” (7%) and “good” (< 1%) scenarios. Conclusions Using simple measurements, we built different aging trajectories, and observed that the worst performers had the highest incidence of dementia. Better knowledge of trajectories of aging would be useful for preventive interventions aimed at promoting healthier aging.

scholarly journals Monte Carlo Computations on molecular flow in pumping speed test domes

Vacuum ◽  
1967 ◽  
Vol 17 (6) ◽  
pp. 342
Author(s):  
Erhard Fischer ◽  
Hans Mommsen
Keyword(s):  
Monte Carlo ◽  
Molecular Flow ◽  
Speed Test

154 The Feasibility of Assessing Sarcopenia Among Older People with Arm Fracture Using Different Criteria

2021 ◽  
Vol 50 (Supplement_1) ◽  
pp. i12-i42
Author(s):  
K Ibrahim ◽  
M A Mullee ◽  
G Lily Yao ◽  
S Zhu ◽  
M Baxter ◽  
...  
Keyword(s):  
Older People ◽  
Grip Strength ◽  
Sensitivity And Specificity ◽  
Gait Speed ◽  
Speed Test ◽  
Increased Risk ◽  
European Working ◽  
Hand Dynamometer ◽  
Risk Of Falls ◽  
And Gender

Abstract Introduction Osteoporosis and sarcopenia often co-exist (osteo-sarcopenia) and both are associated with increased risk of falls and fractures. Early identification and treatment of sarcopenia among older people with fragility arm fractures could prevent further fractures. This study evaluated the feasibility of assessing sarcopenia in a fracture clinic. Methods People aged 65+ years with arm fracture attending fracture clinics in one acute trust were recruited. Sarcopenia was assessed using gait speed, grip strength with unfractured arm (hand dynamometer using appropriate cut off adjusted for age and gender), skeletal muscle mass index SMI (Bioimpedance BIA), SARC-F questionnaire, the European Working Group on Sarcopenia in Older People (EWGSOP) I and II criteria. The sensitivity and specificity of each measure was calculated against the EWGSOP II criteria as the standard reference. Results 100 patients (Mean age 75 years±7.2; 80 female) were recruited. Sarcopenia was identified among 4% (EWGSOP I), 5% (SMI), 13% (EWGSOP II), 16% (gait speed test), 18% (SARC-F) and 39% (grip strength) and was more prevalent among men. SARC-F had the best sensitivity and specificity (100% and 96% respectively) when compared to the EWGSOP II criteria. Sensitivity and specificity for the remaining measures were respectively (100%, 71%) for grip strength, (75%, 94%) for gait speed, (25%, 97%) with SMI and (25%, 99%) for EWGSOP I. Time needed to complete the assessments was 1–2 minutes for gait speed, grip strength and SARC-F; five minutes for BIA test, and nine minutes when EWGSOP I and II criteria were applied. Data were complete for grip strength and SARC-F. Missing data was reported among 2% for gait speed, 8% for BIA test, 8% for EWGSOP II and 10% for EWGSOP I. Conclusion It was feasible to assess sarcopenia in fracture clinics and SARC-F was a quick, simple and sensitive tool suitable for routine use.

scholarly journals Viability of gait speed test in hospitalized elderly patients

2016 ◽  
Vol 42 (3) ◽  
pp. 196-202 ◽  
Author(s):  
Bruno Prata Martinez ◽  
Anne Karine Menezes Santos Batista ◽  
Isis Resende Ramos ◽  
Júlio Cesar Dantas ◽  
Isabela Barboza Gomes ◽  
...  
Keyword(s):  
Elderly Patients ◽  
Gait Speed ◽  
Repeated Measures ◽  
Maximum Speed ◽  
Actual Performance ◽  
Physical Test ◽  
Speed Test ◽  
The Third ◽  
Hospitalized Elderly ◽  
Hospitalized Elderly Patients

ABSTRACT Objective: The gait speed test (GST) is a physical test that can predict falls and aid in the diagnosis of sarcopenia in the elderly. However, to our knowledge, there have been no studies evaluating its reproducibility in hospitalized elderly patients. The objective of this study was to evaluate the safety and reproducibility of the six-meter GST (6GST) in hospitalized elderly patients. Methods: This repeated measures study involved hospitalized elderly patients (≥ 60 years of age) who underwent the 6GST by the fifth day of hospitalization, were able to walk without assistance, and presented no signs of dyspnea or pain that would prevent them from performing the test. The 6GST was performed three times in sequence, with a rest period between each test, in a level corridor. Gait speed was measured in meters/second. Reproducibility was assessed by comparing the means, intraclass correlation coefficients (ICCs) and Bland-Altman plots. Results: We evaluated 110 elderly patients in a total of 330 tests. All participants completed all of the tests. The comparisons between the speeds obtained during the three tests showed high ICCs and a low mean bias (Bland-Altman plots). The correlation and accuracy were greatest when the mean maximum speed was compared with that obtained in the third test (1.26 ± 0.44 m/s vs. 1.22 ± 0.44 m/s; ICC = 0.99; p = 0.001; mean bias = 0.04; and limits of agreement = −0.27 to 0.15). Conclusions: The 6GST was proven to be safe and to have good reproducibility in this sample of hospitalized elderly patients. The third measurement seems to correspond to the maximum speed, since the first two measurements underestimated the actual performance.

Research on Speed Test System of Ultrasonic Motor

2018 ◽  
Author(s):  
JieJi Zheng ◽  
Ning Chen ◽  
Chao Qi ◽  
XiKai Jiao ◽  
ShiXun Fan ◽  
...  
Keyword(s):  
Ultrasonic Motor ◽  
Test System ◽  
Speed Test

scholarly journals Tactile Occupant Detection Sensor for Automotive Airbag

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5288
Author(s):  
Naveen Shirur ◽  
Christian Birkner ◽  
Roman Henze ◽  
Thomas M. Deserno
Keyword(s):  
High Speed ◽  
Tactile Sensors ◽  
Low Velocity ◽  
Speed Test ◽  
Multi Stage ◽  
The Matrix ◽  
Contact Data ◽  
Single Sensor ◽  
Matrix Sensor ◽  
Contact Position

Automotive airbags protect occupants from crash forces during severe vehicle collisions. They absorb energy and restrain the occupants by providing a soft cushion effect known as the restraint effect. Modern airbags offer partial restraint effect control by controlling the bag’s vent holes and providing multi-stage deployment. Full restraint effect control is still a challenge because the closed-loop restraint control system needs airbag–occupant contact and interaction feedback. In this work, we have developed novel single and matrix capacitive tactile sensors to measure the occupant’s contact data. They can be integrated with the airbag surface and folded to follow the dynamic airbag shape during the deployment. The sensors are tested under a low-velocity pendulum impact and benchmarked with high-speed test videos. The results reveal that the single sensor can successfully measure occupant–airbag contact time and estimate the area, while the contact position is additionally identified from the matrix sensor.

Sign in / Sign up

Export Citation Format

Share Document