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Analysis of English Testing Based on Reliability Theory in Language Testing-Taking the English Midterm Test for the First Grade of a Middle School in Hangzhou as an Example
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作者 ZENG Qing-qing 《Journal of Literature and Art Studies》 2024年第7期628-631,共4页
Based on the reliability theory in language testing,this study analyzes the midterm English test of a first grade class in Hangzhou using SPSS software.We will analyze the overall structure and reliability of the test... Based on the reliability theory in language testing,this study analyzes the midterm English test of a first grade class in Hangzhou using SPSS software.We will analyze the overall structure and reliability of the test paper,and use cloze as a representative of objective questions to calculate their difficulty and discrimination,in order to explore the quality of the questions and the mastery of the knowledge learned by students.The purpose of this analysis and research is to improve the quality of exam questions and help teachers get useful information from exam results,thereby improving teaching quality. 展开更多
关键词 English test midterm examination reliability
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Reliability of the K-Force Muscle Controller Dynamometer on Eccentric and Isometric Hip Adduction Strength
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作者 Christos Pippas Antonis Emmanouilidis +2 位作者 Stefanos Karanasios George Koumantakis George Gioftsos 《Open Journal of Therapy and Rehabilitation》 2024年第3期224-235,共12页
Hip adduction strength tests are commonly used in clinical practice to provide an accurate diagnosis of groin injuries. Athletes with reduced adductor muscle strength are at risk of developing groin injuries. Our stud... Hip adduction strength tests are commonly used in clinical practice to provide an accurate diagnosis of groin injuries. Athletes with reduced adductor muscle strength are at risk of developing groin injuries. Our study aimed to evaluate the relative and absolute test-retest reliability of the side-lying eccentric hip adduction strength test and the long-lever adduction squeeze test using the K-Force hand-held dynamometer. Twenty physically active male individuals with a mean age (±SD) of 30.7 (±7.3) years were included. Both tests presented excellent test-retest reliability (Intraclass Correlation Coefficient: 0.77 - 0.95). The best and mean scores of the eccentric and isometric tests presented the smallest test-retest variation (MDC%: 12.8 - 14.9 and MDC%: 14.6 - 18.7, respectively). Our study showed that the K-Force dynamometer has excellent reliability for assessing hip adduction strength in two different testing positions. We suggest the best and mean of three repetitions for clinical practice as they present the lowest variability. Further research evaluating its clinimetric properties in different populations and gender is recommended. 展开更多
关键词 ADDUCTOR GROIN Strength testing DYNAMOMETER reliability
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Aging effect and test-retest reliability of the sinusoidal harmonic acceleration test and velocity step test using nanotorque rotatory chair 被引量:1
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作者 Nourhan Ghoraba Samir Assal Doaa Elmoazen 《Journal of Otology》 CAS CSCD 2023年第3期125-131,共7页
Introduction:Rotatory chair testing has been used to evaluate horizontal canal function.Frequently used tests include sinusoidal harmonic acceleration test(SHAT)and velocity step test(VST).Objectives:Assessment of age... Introduction:Rotatory chair testing has been used to evaluate horizontal canal function.Frequently used tests include sinusoidal harmonic acceleration test(SHAT)and velocity step test(VST).Objectives:Assessment of age effect on the SHAT and VST and assessment of test-retest reliability of the parameters of those two tests.Methods:A prospective study was performed on 100 subjects with no ear or vestibular complaints and normal vestibular evaluation.They were divided into two groups;Group A:below 50 years of age and Group B:50 years of age or above.SHAT was presented at frequencies 0.02,0.04,0.08,0.16,0.32,0.64 Hz with a peak velocity of 60°/s.VST was performed using a maximum velocity of 100°/s with acceleration and deceleration of 200°/s2.Thirty subjects were tested twice to assess reliability.Results:Study participants ranged in age from 20 to 67 years.Regarding group A,the mean age was30.92±7.31 and 55.36±4.61 for group B.No significant differences were found in SHAT parameters between the two groups.As well,there was no significant difference in VST per-rotatory time constant,however,post-rotatory time constant was significantly longer for Group B(P value<0.05).Intraclass correlation coefficient(ICC)values showed moderate to good reliability(ICC 0.5800.818)for SHAT parameters for the lower frequencies and indicated moderate reliability for VST time constant(ICC 0.5090.652).Conclusions:Age has no significant effect on the parameters of SHAT and VST.Test-retest reliability is generally good for both tests. 展开更多
关键词 Rotatory chair testing Sinusoidal harmonic acceleration test Velocity step test Age effect test-retest reliability
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A Planning Method for Operational Test of UAV Swarm Based on Mission Reliability
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作者 Jingyu Wang Ping Jiang Jianjun Qi 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第8期1889-1918,共30页
The unmanned aerial vehicle(UAV)swarm plays an increasingly important role in the modern battlefield,and the UAV swarm operational test is a vital means to validate the combat effectiveness of the UAV swarm.Due to the... The unmanned aerial vehicle(UAV)swarm plays an increasingly important role in the modern battlefield,and the UAV swarm operational test is a vital means to validate the combat effectiveness of the UAV swarm.Due to the high cost and long duration of operational tests,it is essential to plan the test in advance.To solve the problem of planning UAV swarm operational test,this study considers the multi-stage feature of a UAV swarm mission,composed of launch,flight and combat stages,and proposes a method to find test plans that can maximize mission reliability.Therefore,a multi-stage mission reliability model for a UAV swarm is proposed to ensure successful implementation of the mission.A multi-objective integer optimization method that considers both mission reliability and cost is then formulated to obtain the optimal test plans.This study first constructs a mission reliability model for the UAV swarm in the combat stage.Then,the launch stage and flight stage are integrated to develop a complete PMS(Phased Mission Systems)reliability model.Finally,the Binary Decision Diagrams(BDD)and Multi Objective Quantum Particle Swarm Optimization(MOQPSO)methods are proposed to solve the model.The optimal plans considering both reliability and cost are obtained.The proposed model supports the planning of UAV swarm operational tests and represents a meaningful exploration of UAV swarm test planning. 展开更多
关键词 UAV swarm PMS MOQPSO BDD mission reliability operational test planning
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Discussion on the Importance of Reliability and Validity in Language Testing
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作者 李佳 《科技信息》 2010年第29期217-217,411,共2页
When talked about the language testing, we need to focus on the reliability and validity,the paper explains the importance of reliability and validity and why should we focus on them when we make language testing pape... When talked about the language testing, we need to focus on the reliability and validity,the paper explains the importance of reliability and validity and why should we focus on them when we make language testing paper. Also list various factors that affect reliability and validity. 展开更多
关键词 英语学习 学习方法 语言学 语言测试信度
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Reliability and Validity of the English Oral Test
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作者 王芳 《科技信息》 2009年第24期I0126-I0126,I0128,共2页
English oral test aimsto provide a fair and valid measure of a testee'soral proficiency so asto give an accurate description of his/her oral communicative ability.This paper analysesthe validity and reliability of... English oral test aimsto provide a fair and valid measure of a testee'soral proficiency so asto give an accurate description of his/her oral communicative ability.This paper analysesthe validity and reliability of the college entrance English oral test paper of Guangdong province of 2005.In designing an oral test,in order to make the test reliable,the teacher should take the following factors into consideration:test content,test method,testees'mood,rating scales and rater characteristics. 展开更多
关键词 语言学 英语教学 教学方法 翻译
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Research on the overload protection reliability of moulded case circuit-breakers and its test device 被引量:14
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作者 LI Kui LU Jian-guo +2 位作者 WU Yi QIN Zhi-jun YAO Dong-mei 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第3期453-458,共6页
This paper analyzed the reliability and put forward the reliability index of overload protection for moulded case circuit breaker. The success rate was adopted as its reliability index of overload protection. Based on... This paper analyzed the reliability and put forward the reliability index of overload protection for moulded case circuit breaker. The success rate was adopted as its reliability index of overload protection. Based on the reliability index and the reli- ability level, the reliability examination plan was analyzed and a test device for the overload protection of moulded case cir- cuit-breaker was developed. In the reliability test of overload protection, two power sources were used, which reduced the time of conversion and regulation between two different test currents in the overload protection test, which made the characteristic test more accurate. The test device was designed on the base of a Windows system, which made its operation simple and friendly. 展开更多
关键词 Moulded case circuit breakers Overload protection reliability test device
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Reliability testing and reliability analysis of the over-load protective relay 被引量:4
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作者 ZHAO Jing-ying CHEN Hong-jian +2 位作者 LIU Guo-jin ZHANG Yong WU Pin-hua 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第3期475-480,共6页
The over-load protective relay is widely used directly affects the safe running of a motor. The reliability for motor protection. The reliability of the over-load protective relay testing and reliability analysis of t... The over-load protective relay is widely used directly affects the safe running of a motor. The reliability for motor protection. The reliability of the over-load protective relay testing and reliability analysis of the over-load protective relay is an important way to improve the reliability of products. In this paper, the reliability test method of the over-load protective relay is studied, and the reliability tests of the typical products are carried out on a reliability tester developed by authors. In terms of the testing results, the reliability analysis is finished. The failure reasons are found and the measures are put forward to improve the reliability of the products. 展开更多
关键词 Over-load protective relay Protective success analysis ratio Sampling and checking plan reliability testing reliability analysis
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Empirical Measurement of the Software Testing and Reliability 被引量:1
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作者 ZouFeng-zhong XuRen-zuo 《Wuhan University Journal of Natural Sciences》 EI CAS 2004年第1期23-26,共4页
The meanings of parameters of software reliabi- lity models are investigated in terms of the process of the software testing and in terms of other measurements of software. Based on the investigation, the empirical e... The meanings of parameters of software reliabi- lity models are investigated in terms of the process of the software testing and in terms of other measurements of software. Based on the investigation, the empirical estimation of the parameters is addressed. On one hand, these empirical estimates are also measurements of the software, which can be used to control and to optimize the process of the software development. On the other hand, by treating these empirical estimates as Bayes priors, software reliability models are extended such that the engineers’ experience can be integrated into and hence to improve the models. 展开更多
关键词 software reliability MODELS software testing prior Bayesian analysis
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Reliability and Validity Test of Questionnaire on the Adaptation Strategy of Cryosphere Changes in Arid Inland River Basin
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作者 WANG Ying-wei1, LIU Shou-dong1, DENG Mao-zhi2,3 1. School of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044, China 2. Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China 3. State Key Laboratory of Cryospheric Sciences, Chinese Academy of Sciences, Lanzhou 730000, China 《Meteorological and Environmental Research》 CAS 2011年第4期1-4,8,共5页
[Objective] The aim was to test the reliability and validity of questionnaire on the adaptation strategy of cryosphere changes in arid inland river basin. [Method] A questionnaire on 'the adaptation strategy of cr... [Objective] The aim was to test the reliability and validity of questionnaire on the adaptation strategy of cryosphere changes in arid inland river basin. [Method] A questionnaire on 'the adaptation strategy of cryosphere changes in arid inland river basin' was carried out in Urumchi River basin and Aksu River basin, and its reliability and validity were tested by means of statistical method, so as to investigate the stability and accuracy of questionnaire. [Result] Reliability analysis of questionnaire showed that the split-half reliability coefficient of questionnaire in Urumchi River basin and Aksu River basin was 0.729 and 0.750, respectively, and Cronbach’s α reliability coefficient was 0.613 and 0.616, respectively, which revealed that the questionnaire had good equivalence and internal consistency which reflected good reliability and stability. According to validity analysis on questionnaire, there was significant correlation between the score of most questions and questionnaire, and it indicated that questionnaire had high content validity. There were 8 common factors collected from 26 questions, which were summarized as agricultural planting, agricultural water conservation, life satisfaction, cultivated land variation, social integration sense, climate and cryosphere changes, capital input improved by environment and family economic condition, respectively. Meanwhile, the contribution rate of various questions in corresponding indexes was higher, and reflected structure was in full accord with questionnaire content, which revealed that questionnaire owned good construct validity. [Conclusion] With higher stability and accuracy, the questionnaire could determine the desired topic and content and was suitable for the study on the perception of common people and choices of adaptive strategy under cryosphere changes in arid inland river basin in northwestern China. 展开更多
关键词 Cryosphere changes Adaptive strategy QUESTIONNAIRE reliability and validity test China
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Test-Retest Reliability, Convergent Validity and Practice Effects of the RBANS in a Memory Clinic Setting: A Pilot Study
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作者 Yanhong Dong Claire L. Thompson +3 位作者 Shi Huey Joanne Tan Leon Ben Swie Lim Wanshin Pang Christopher Li-Hsian Chen 《Open Journal of Medical Psychology》 2013年第4期11-16,共6页
This pilot study examined the psychometric properties and clinical utility of a brief neuropsychological instrument (Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The test-retest reliabil... This pilot study examined the psychometric properties and clinical utility of a brief neuropsychological instrument (Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The test-retest reliability, practice effects and convergent validity of RBANS were examined in participants without objective cognitive impairment. The tests were administered at two time points at approximately a two weeks’ interval, with 30 cognitively intact participants with a mean age of 63.3 ± 5.8 years. Adequate test-retest reliabilities were found for RBANS subtests, index and total scale scores with significant gain scores in immediate memory and visuospatial function. The RBANS showed good convergent validity and the RBANS supplemented with executive and language measures (Colour Trails Test and 30-item modified Boston Naming Test, respectively) demonstrated excellent convergent validity with a formal neuropsychological battery. This pilot study has provided the preliminary evidence of reliability and convergent validity of the RBANS. Additionally, it also provides insight on the practice effects so that clinicians may assess significant changes in RBANS subtests and domain indexes for clinical practice. 展开更多
关键词 RBANS NEUROPSYCHOLOGICAL tests test-REtest reliability Validity Practice Effect
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An Empirical Study on the Reliability and Validity of English Tests
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作者 张妮 《西安翻译学院学报》 2017年第2期61-64,共4页
The paper makes a study on six parts, namely, speaking, writing, sentence, cloze, reading and listening in an English test with students at two different proficiency levels. Their score data were studied through relia... The paper makes a study on six parts, namely, speaking, writing, sentence, cloze, reading and listening in an English test with students at two different proficiency levels. Their score data were studied through reliability analysis, validity analysis, factor analysis and analysis of variance ( ANOVA) to conduct the validation of this English test. The paper tries to explore the score data internal consistency, group difference recognition to maintain the objectivity and accuracy in English tests. 展开更多
关键词 reliability and Validity ENGLISH testS ASSESSMENT STATISTICAL Methods
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Effect of slake durability on time dependent swelling behavior of red-bed siltstone in Sichuan Basin
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作者 JIA Qinji Ruben Angel GALINDO AIRES +1 位作者 LIU Xiaoming XU Haifeng 《Journal of Mountain Science》 SCIE CSCD 2024年第9期3123-3138,共16页
The swelling behavior of red-bed rocks is a significant factor in the abnormal uplift of subgrades for high-speed railways constructed on the red stratum in the Sichuan Basin,China.The prime objective of this paper is... The swelling behavior of red-bed rocks is a significant factor in the abnormal uplift of subgrades for high-speed railways constructed on the red stratum in the Sichuan Basin,China.The prime objective of this paper is to investigate the impact of mineralogical composition,moisture content,and overburden load on the time-dependent unconfined and oedometric swelling behavior of red-bed siltstone in the context of differences in the slake durability.Twenty samples were prepared for the swelling test,with eleven used for the unconfined swelling and slake index tests and nine for the oedometric swelling test.The temporal dependency of swelling is characterized by the viscosity coefficient of water absorption in a proposed swelling model.Results indicate that the swelling deformation of red-bed rocks is due to a combination of hydration swelling within the rock matrix and crack expansion caused by air breakage.In the unconfined swelling test,the final axial swelling strain of red-bed rocks decreases linearly with increasing slake index,while the viscosity coefficient increases exponentially with the slake index.In the oedometric swelling test,red-bed rocks with lower slake durability show greater sensitivity to lateral constraint and overburden load compared to those with higher slake durability. 展开更多
关键词 Rock swelling Slake durability Time effect Unconfined swelling test Oedometric swelling test
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Evaluation Test Research of DR Inspection System for Circumferential Welds in Long Distance Pipeline
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作者 WANG Changjiang WANG Xue +4 位作者 ZHANG Shimin ZHAO Yan LYU Xinyu ZHONG Qian ZHOU Guangyan 《材料导报》 EI CAS CSCD 北大核心 2024年第22期223-229,共7页
Digital radiographic(DR)testing equipment has been widely promoted and applied in the inspection of circumferential welds in oil and gas pipelines.In order to establish a comprehensive quality control system for digit... Digital radiographic(DR)testing equipment has been widely promoted and applied in the inspection of circumferential welds in oil and gas pipelines.In order to establish a comprehensive quality control system for digital radiographic testing and fully evaluate the integrated system inspection ability of equipment,personnel,and processes,a scientific and standardized evaluation method to the system is very necessary.Here investigates the precedents of relevant non-destructive testing evaluation methods at home and abroad,considers the testing characteristics of DR equipment,develops a complete set of DR testing system evaluation procedures.It deeply studies the adaptability methods of program processes from defect production to slicing processing and data statistical calculation for digital radiographic testing evaluation.To check the repeatability and reliability of the detectable system,five process welds with 200 real metallographic defects were fabricated in the laboratory.From the detected results,the DR system has good repeatability in image quality,and the detectable defect size reaches 0.85 mm under achieving 90%detection probability at a confidence level of 95%,the error of detected defect length is±2 mm,and the error of detected defect localization is±5 mm.The qualitative and quantitative detection of defects are accurate and reliable.The test further confirmed the reliable detection ability of the DR detection system,and fully validated the scientific and practical evaluation method designed.The research on the evaluation test method can serve as an important link in the quality control system for the on-site application of digital ray equipment in long-distance pipelines.The designed program,test,and evaluation content can serve as an important basis for the formulation of relevant specifications or standards. 展开更多
关键词 digital ray evaluation test REPEATABILITY reliability
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Analysis on the development of chemically-improved soil in railway engineering
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作者 Feng Chen Zhongjin Wang +1 位作者 Dong Zhang Shuai Zeng 《Railway Sciences》 2024年第2期216-226,共11页
Purpose-Explore the development trend of chemically-improved soil in railway engineering.Design/methodology/approach–In this paper,the technical standards home and abroad were analyzed.Laboratory test,field test and ... Purpose-Explore the development trend of chemically-improved soil in railway engineering.Design/methodology/approach–In this paper,the technical standards home and abroad were analyzed.Laboratory test,field test and monitoring were carried out.Findings–The performance design system of the chemically-improved soil should be established.Originality/value–On the basis of the performance design,the test methods and standards for various properties of chemically-improved soil should be established to evaluate the improvement effect and control the engineering quality. 展开更多
关键词 durability DEFORMATION Engineering properties Chemically-improved soil Performance design test method
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Test-retest strength reliability of the Electronic Push/Pull Dynamometer (EPPD) in the measurement of the quadriceps and hamstring muscles on a new chair
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作者 Mikhled F. Maayah Mohammad D. Al-Jarrah +7 位作者 Saad S. El Zahrani Ali H. Alzahrani Emad T. Ahmedv Amr A. Abdel-Aziem Gopichandran Lakshmanan Nabeel A. Almawajdeh Muhsen B. Alsufiany Yaser O. M. Abu Asi 《Open Journal of Internal Medicine》 2012年第2期123-128,共6页
Background: Test-retest strength reliability of the Electronic Push/Pull Dynamometer (EPPD) in the measurement of the extensor and flexor muscles on a new constructed chair. The objective of the study was to assess re... Background: Test-retest strength reliability of the Electronic Push/Pull Dynamometer (EPPD) in the measurement of the extensor and flexor muscles on a new constructed chair. The objective of the study was to assess reliability of Electronic Push/Pull Dynamometer in the measurement of the knee flexion and extension at 90° and 60° on a new constructed chair. The aims of the author: To assess reliability of Electronic Push/Pull Dynamometer in the measurement of the knee flexion and extension at 90° and 60° on a new constructed chair. Design: A test-retest reliability study. Subjects: One hundred healthy students male and female (mean age, 21y). Methods: Maximum isometric strength of the quadriceps and hamstring muscle groups was measured using the EPPD were recorded at 60° and 90° for 3 trials on 2 occasions. Reliability was assessed with the Intraclass correlation coefficient (ICC), mean and standard deviation (SD) of measurements, and smallest real differences were calculated for the maximum and for the mean and work of the 3 repetitions. Results: Mean strength ranged from 50.44 kg for knee flexion to 55.76 kg for knee extension 50.44 kg to 61.98 kg at 90° hip flexion. Test-retest reliability Intraclass correlation coefficients (ICCs) ranged from 0.85 to 0.99. ICCs for test-retest reliability ranged from 0.780 to 0.998. Conclusions: The results of the reliability study indicate that the EPPD in reliable dynamometer to use in determining lower limb muscle force production. It can be used to measure disease progression and to evaluate changes in knee extension and flexion strength at the individual patient level. 展开更多
关键词 Muscle Strength reliability test-REtest Hand-Held DYNAMOMETER ELECTRONIC Pull/Push DYNAMOMETER
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Interpretation of Key Concepts in Language Testing: Validity, Validation and Reliability
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作者 黄丽娜 《海外英语》 2013年第21期262-263,共2页
Language testing is an important link in language teaching,in this paper,the two important criteria of language test the reliability and validity has carried on the detailed elaboration,in order to a language teacher ... Language testing is an important link in language teaching,in this paper,the two important criteria of language test the reliability and validity has carried on the detailed elaboration,in order to a language teacher proposition and evaluation test more scientific. 展开更多
关键词 LANGUAGE testing STandARD reliability validity
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Validity and Reliability of an English Test Paper in Junior Middle School
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作者 轩慧芳 《海外英语》 2012年第18期103-105,共3页
Test plays an important role in our lives in that it can cause backwash towards our teaching and learning.Thus the pur pose of the present study is to examine the quality of an English test paper in a junior middle sc... Test plays an important role in our lives in that it can cause backwash towards our teaching and learning.Thus the pur pose of the present study is to examine the quality of an English test paper in a junior middle school of Urumqi according to the language test theories.Through the data collection and analyses,the results indicate that the test paper is a medium-level test and the reliability is suitable.From the correlation analysis,we can see that each part has a high correlation value to the total,indicat ing that all of them contribute to generate language proficiency. 展开更多
关键词 LANGUAGE test validity reliability
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Measuring Reliability of A Web Portal Based on Testing Profile
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作者 Malik Muhammad Ali Shahid Shahida Sulaiman +7 位作者 Mohammed Al-Sarem Aqeel Ur Rahman Salman Iqbal Rab Nawaz Bashir Arfat Ahmad Khan Momen M.Alrawi Rashiq R.Marie Settawit Poochaya 《Computers, Materials & Continua》 SCIE EI 2023年第3期6641-6663,共23页
Conventionally,the reliability of a web portal is validated with generalized conventional methods,but they fail to provide the desired results.Therefore,we need to include other quality factors that affect reliability... Conventionally,the reliability of a web portal is validated with generalized conventional methods,but they fail to provide the desired results.Therefore,we need to include other quality factors that affect reliability such as usability for improving the reliability in addition to the conventional reliability testing.Actually,the primary objectives of web portals are to provide interactive integration of multiple functions confirming diverse requirements in an efficient way.In this paper,we employ testing profiles tomeasure the reliability through software operational profile,input space profile and usability profile along with qualitative measures of reliability and usability.Moreover,the case study used for verification is based on aweb application that facilitates information and knowledge sharing among its online members.The proposed scheme is compared with the conventional reliability improvement method in terms of failure detection and reliability.The final results unveil that the computation of reliability by using the traditional method(utilizing failure points with the assistance of Mean Time Between Failures(MTBF)and Mean Time To Failure(MTTF)becomes ineffective under certain situations.Under such situations,the proposed scheme helps to compute the reliability in an effective way.Moreover,the outcomes of the study provide insight recommendations about the testing and measurement of reliability for Web based software or applications. 展开更多
关键词 Software usability software reliability web portals software testing software testing profile
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Mechanical Test and Meso-Model Numerical Study of Composite Rubber Concrete under Salt-Freezing Cycle
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作者 Mingkai Sun Yanan Wang +3 位作者 Pingwei Jiang Zerong Song Zhan Gao Jiaming Xu 《Journal of Renewable Materials》 SCIE EI 2023年第2期643-668,共26页
A composite rubber concrete(CRC)was designed by combining waste tire rubber particles with particle sizes of 3~5 mm,1~3 mm and 20 mesh.Taking the rubber content of different particle sizes as the influencing factors,t... A composite rubber concrete(CRC)was designed by combining waste tire rubber particles with particle sizes of 3~5 mm,1~3 mm and 20 mesh.Taking the rubber content of different particle sizes as the influencing factors,the range and variance analysis of the mechanical and impermeability properties of CRC was carried out by orthogonal test.Through analysis,it is concluded that the optimal proportion of 3~5 mm,1~3 mm,and 20 mesh particle size composite rubber is 1:2.5:5.5 kinds of CRC and 3 kinds of ordinary single-mixed rubber concrete(RC)with a total content of 10%~20%were designed under this ratio,and the salt-freezing cycle test was carried out with a concentration of 5%Na 2 SO4 solution.The physical and mechanical damage laws during 120 salt-freezing cycles are obtained,and the corresponding damage prediction model is established according to the experimental data.The results show that:on the one hand,the composite rubber in CRC produces a more uniform“graded”structure,forms a retractable particle group,and reduces the loss of mechanical properties of CRC.On the other hand,colloidal particles with different particle sizes are used as air entraining agent to improve the pore structure of concrete and introduce evenly dispersed bubbles,which fundamentally improves the durability of concrete.Under the experimental conditions,the CRC performance is the best when the overall content of composite rubber is 15%. 展开更多
关键词 Waste rubber composite rubber concrete orthogonal test mechanical properties durability
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