The Origin of the Composite Wheeled Vehicle, Two-Wheeled Trailer, and Tracked Vehicle Vibration Schedules in MIL-STD-810D/E

1997 ◽  
Vol 40 (2) ◽  
pp. 31-37
Author(s):  
William Connon
Keyword(s):  
Development Process ◽  
Normal Operation ◽  
Test Time ◽  
Test Scenario ◽  
Final Test ◽  
Test Procedures ◽  
Vibration Data ◽  
Wheeled Vehicle ◽  
Test Operations ◽  
Schedule Development

In the early and mid-1980s, a concerted effort was made at the Aberdeen Test Center (then Combat Systems Test Activity) to collect vibration data on a wide variety of vehicles to create laboratory vibration test schedules. The initial schedules were published in MIL-STD-810D and were updated for publication in MIL-STD-810E and ITOP (International Test Operations Procedure) 1-2-601. Although the vehicles used for schedule development are listed in the documents and a test scenario is described, little information has been published describing how the test levels compare with the actual measured levels and how the test courses used compare with the terrain likely to be encountered in the vehicle's normal operation. This paper describes the data acquisition and analysis efforts to show where and how measurements were made and how the final test levels relate to the actual measured levels. It will also describe the test courses used and show how they relate to "civilian sector" conditions such as operation on an unpaved road. The purpose of the paper is to provide an understanding of the physical severity represented by the test procedures used and the amount of conservatism and level exaggeration (to reduce test time) built into the schedule development process.

scholarly journals THE USE OF WEB-BASED EXAM (WBE) TO OPTIMIZE STUDENTS� TESTING RESULT

2018 ◽  
Vol 6 (2) ◽  
pp. 41
Author(s):  
Abdul Ngafif
Keyword(s):  
Answer Sheet ◽  
Access Point ◽  
Test Time ◽  
Testing System ◽  
Research Model ◽  
Final Test ◽  
Web Based ◽  
Whole Process ◽  
System 2 ◽  
Exam System

This research was conducted based on theproblems found during the mid and final test by using paper and pen test; those are the students tend to do cheating, the sleepy supervisors, the inconsistency of test time, and the risk of losing the answer sheet. Therefore, the goals of the research are; 1) to make an appropriate WBE testing system, 2) to know the cheating rate of the students, 3) to find out the effectiveness of the system, and 4) to inform the benefits that might be taken by the WBE testing system�s users. By applyingRnD research model, the researcher applies a concept called web-based exam system which uses three main tools to run the system (teacher�s laptop as the server, WBE software, and access point to communicate the server and the user). The results indicated that the system reduces the students� cheating rate 100%. Then, from the questionnaire given, the teacherstend to likeusing WBE testing system because they can monitor the whole process of the test from his own laptop and the result of the test will be analyzed and be saved automatically in his laptop. Moreover, it reduces time consumption and paper use.Keywords: web-based exam, testing system, testing result, cheating, software

scholarly journals Automated Smartphone Threshold Audiometry: Validity and Time Efficiency

2017 ◽  
Vol 28 (03) ◽  
pp. 200-208 ◽  
Author(s):  
Jessica van Tonder ◽  
De Wet Swanepoel ◽  
Faheema Mahomed-Asmail ◽  
Hermanus Myburgh ◽  
Robert H. Eikelboom
Keyword(s):  
Repeated Measures ◽  
Cost Effective ◽  
Test Time ◽  
Test Duration ◽  
Test Procedures ◽  
Paired Samples ◽  
Significant Difference ◽  
Effective Option ◽  
Adolescent Sample ◽  
Air Conduction

AbstractSmartphone-based threshold audiometry with automated testing has the potential to provide affordable access to audiometry in underserved contexts.To validate the threshold version (hearTest) of the validated hearScreen™ smartphone-based application using inexpensive smartphones (Android operating system) and calibrated supra-aural headphones.A repeated measures within-participant study design was employed to compare air-conduction thresholds (0.5–8 kHz) obtained through automated smartphone audiometry to thresholds obtained through conventional audiometry.A total of 95 participants were included in the study. Of these, 30 were adults, who had known bilateral hearing losses of varying degrees (mean age = 59 yr, standard deviation [SD] = 21.8; 56.7% female), and 65 were adolescents (mean age = 16.5 yr, SD = 1.2; 70.8% female), of which 61 had normal hearing and the remaining 4 had mild hearing losses.Threshold comparisons were made between the two test procedures. The Wilcoxon signed-ranked test was used for comparison of threshold correspondence between manual and smartphone thresholds and the paired samples t test was used to compare test time.Within the adult sample, 94.4% of thresholds obtained through smartphone and conventional audiometry corresponded within 10 dB or less. There was no significant difference between smartphone (6.75-min average, SD = 1.5) and conventional audiometry test duration (6.65-min average, SD = 2.5). Within the adolescent sample, 84.7% of thresholds obtained at 0.5, 2, and 4 kHz with hearTest and conventional audiometry corresponded within ≤5 dB. At 1 kHz, 79.3% of the thresholds differed by ≤10 dB. There was a significant difference (p < 0.01) between smartphone (7.09 min, SD = 1.2) and conventional audiometry test duration (3.23 min, SD = 0.6).The hearTest application with calibrated supra-aural headphones provides a cost-effective option to determine valid air-conduction hearing thresholds.

Step-Stress Accelerated Random Vibration Life Testing

2010 ◽  
Vol 118-120 ◽  
pp. 606-610 ◽  
Author(s):  
Fu Qiang Sun ◽  
Xiao Yang Li ◽  
Jing Rui Zhang ◽  
Tong Min Jiang
Keyword(s):  
Parameter Estimation ◽  
Sample Size ◽  
Stress Level ◽  
Random Vibration ◽  
Normal Operation ◽  
Test Time ◽  
Life Testing ◽  
Vibration Testing ◽  
Testing Method ◽  
Technical Basis

In order to reduce the sample size and test time, a step-stress accelerated random vibration life testing (ARVLT) method is presented. And the method of parameter estimation is also proposed. Through this testing method, the exaggeration factor K can be obtained rapidly, so that the result can be used as the technical basis of conducting an equivalent accelerated vibration testing of the product. In addition, the reliability of the product under the normal operation stress level can be extrapolated.

scholarly journals An Improved Dual-Kurtogram-Based T 2 Control Chart for Condition Monitoring and Compound Fault Diagnosis of Rolling Bearings

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Zhiyuan Jiao ◽  
Wei Fan ◽  
Zhenying Xu
Keyword(s):  
Fault Diagnosis ◽  
Control Chart ◽  
Condition Monitoring ◽  
Control Limit ◽  
Normal Operation ◽  
Multivariate Statistical ◽  
Statistical Process ◽  
Envelope Analysis ◽  
Spectral Kurtosis ◽  
Vibration Data

Condition monitoring and compound fault diagnosis are crucial key points for ensuring the normal operation of rotating machinery. A novel method for condition monitoring and compound fault diagnosis based on the dual-kurtogram algorithm and multivariate statistical process control is established in this study. The core idea of this method is the capability of the dual-kurtogram in extracting subbands. Vibration data under normal conditions are decomposed by the dual-kurtogram into two subbands. Then, the spectral kurtosis (SK) of Subband I and the envelope spectral kurtosis (ESK) of Subband II are formulated to construct a control limit based on kernel density estimation. Similarly, vibration data that need to be monitored are constructed into two subbands by the dual-kurtogram. The SK of Subband I and the ESK of Subband II are calculated to derive T 2 statistics based on the covariance determinant. An alarm will be triggered when the T 2 statistics exceed the control limit and suitable subbands for square envelope analysis are adopted to obtain the characteristic frequency. Simulation and experimental data are used to verify the feasibility of the proposed method. Results confirm that the proposed method can effectively perform condition monitoring and fault diagnosis. Furthermore, comparison studies show that the proposed method outperforms the traditional T 2 control chart, envelope analysis, and empirical mode decomposition.

scholarly journals Pengembangan Buku Ajar Akidah Akhlak untuk Meningkatkan Pemahaman Siswa Madrasah

2019 ◽  
Vol 3 (2) ◽  
pp. 362-375
Author(s):  
Zainuddin Zainuddin
Keyword(s):  
Learning Outcomes ◽  
Error Rate ◽  
Development Process ◽  
T Test ◽  
Test Results ◽  
Final Test ◽  
Test Result

Based on the development process and the test results of the target, it can be concluded as follows (1) result of this activity in the form of textbook of Akidah Akhlak for Madrasah Ibtidaiyah, (2) average learning outcomes in the final test after using textbook increased to 77.25% compared with 67.00% of average learning outcomes in the final test before using textbook. Refers to the T-test and Sig (2-tailed) test result is 0.001 after being compared with the received error rate is 0.05, the developed textbook has been effective.

scholarly journals Estudo Comparativo de Tecnologias de Desenvolvimento front-end paraWeb

2021 ◽  
Author(s):  
Matheus De Souza ◽  
Eduardo Alves da Silva
Keyword(s):  
User Interfaces ◽  
Development Process ◽  
Web Applications ◽  
Use Case ◽  
Test Scenario ◽  
User Interactions ◽  
Advantages And Disadvantages ◽  
Front End ◽  
Startup Time ◽  
Web Systems

There are several JavaScript technologies intended to assist in theconstruction of web systems user interfaces. Choose the most suitablefor a new project can be a difficult task. Three of these technologieshave gained prominence: Angular, Vue and React. All focusedon the front-end development of web applications. In order to facilitatethe process of decision making about which technology is themost suitable in a new project, this work establishes a comparativestudy of the three most used JavaScript technologies currently andto highlight the advantages and disadvantages of each one. Thiswork adopted performance, size and support for different browsersto carry out an experimental comparative study. An applicationwas developed as a use case and replicated in each of the technologies,in order to analyze the development process and the resultsunder the same set of tests. A software to perform the tests in anautomated way was implemented to collect the performance resultsusing the Google Chrome browser. It was possible to identify whichtechnology is most suitable in each test scenario. For example, theAngular framework performed better in 8 out of 10 scenarios evaluated,despite having a longer startup time and build size of theapplication compared to React and Vue. It is estimated that Angularloads more information in the initialization process to make thestate of the application “more prepared” for user interactions

Loudspeaker-based sound reproduction for evaluating noise transmission into the car cabin

2021 ◽  
Vol 263 (6) ◽  
pp. 886-893
Author(s):  
Matthieu Kuntz ◽  
Gregor-Johannes Müller ◽  
Peter Kalinke ◽  
Bernhard U. Seeber
Keyword(s):  
Development Process ◽  
Sound Field ◽  
Sound Quality ◽  
Anechoic Chamber ◽  
Test Procedures ◽  
Field Recording ◽  
Testing Facility ◽  
Airborne Noise ◽  
Reference Measurements ◽  
Key Parameter

Virtual and laboratory-based design techniques can accelerate the development process over conventional prototype-and-field-test procedures. In car acoustics, the transmission of outside airborne noise into the cabin needs to be understood and managed. Here, we evaluate the accuracy of sound field recording and reproduction techniques for investigating the transmission of airborne noise into the driver's cabin of a car. Reference measurements of a real sound field, generated by a truck with idling engine to create a realistic scenario, were carried out in a semi-anechoic chamber. The reference sound field was recorded inside and around a test car. Additionally, a spatial recording of the reference sound field was carried out and used to reproduce the reference sound field over a loudspeaker array in a different, fully anechoic chamber, where the sound field was again measured inside and around the same test car. A comparison of the measured loudness inside the test car shows that this key parameter for sound quality could be reproduced rather faithfully over a loudspeaker array in a controlled testing facility.

Determining the Transport Properties of Rock Specimens Using an Improved Laboratory Through-Diffusion Technique

2006 ◽  
Vol 932 ◽  
Author(s):  
M. Zhang ◽  
M. Takeda ◽  
H. Nakajima
Keyword(s):  
Diffusion Coefficient ◽  
Transport Properties ◽  
Effective Diffusion Coefficient ◽  
Effective Diffusion ◽  
Capacity Factor ◽  
Test Time ◽  
Test Procedures ◽  
Geological Materials ◽  
Concentration Changes ◽  
Through Diffusion

ABSTRACTThe safe disposal of radioactive nuclear wastes using multi-barrier systems requires a good understanding of their transport properties in geological materials. When groundwater flow is very slow, the most important mechanisms of transport and retardation are diffusion through and sorption onto geological materials, and an evaluation of relevant parameters, particularly the effective diffusion coefficient and rock capacity factor (or sorption coefficient), is of fundamental importance to any safety assessment. Although laboratory diffusion tests can be used to determine these two parameters, conventional through-diffusion testing has some limitations, such as the need for a relatively long test time, cumbersome test procedures and the possibility of errors due to differences between analytical assumptions and actual test conditions. In this paper, we offer a rigorous solution to the through-diffusion test. Boundary conditions are improved by taking into account concentration changes in both the source and the measurement cells. A companion approach for back-calculating the effective diffusion coefficient and rock capacity factor is also proposed. The effectiveness and advantages of this improved technique are demonstrated using experimental data derived from a sedimentary rock sample taken from a research site in Japan.

Do You Know that Your Accelerated Vibration Test Requirement Is Correct?

2012 ◽  
Vol 55 (1) ◽  
pp. 68-79
Author(s):  
Dustin Aldridge
Keyword(s):  
Theory And Practice ◽  
Accelerated Testing ◽  
Test Time ◽  
Vibration Test ◽  
Complete Understanding ◽  
Test Procedures ◽  
Time Compression ◽  
Testing Theory ◽  
Many Sources ◽  
Development And Validation

Vibration test time-compression methods have existed for decades and are well-documented. However, not all practitioners are aware of how these methods were developed and the proper utilization of the developed theory. While many sources have attempted to clarify the methodology, there is confusion on many points. The objective of this paper is to help new vibration test engineers understand accelerated testing theory and practice. The lab is a valuable training ground, but sometimes the subtleties are not communicated. A more complete understanding of the theory and practice of vibration test time-compression methods is needed when translating contract requirements into test procedures used in product development and validation.

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