A study of the validity and reliability of the Teacher Homework Involvement Scale: A psychometric evaluation

The aim of the present investigation is to validate the Teacher Homework Involvement Scale (THIS) based on the data from 918 secondary school students. Using a randomized split of the sample, we performed exploratory factor analysis (EFA) on Group 1 (n = 459) and confirmatory factor analysis (CFA) on Group 2 (n = 459). The results indicated that the THIS consisted of three distinct yet related subscales: Homework Quality, Feedback Quality, and Autonomy Support. In addition, the present investigation found an adequate level of factor loading invariance across gender. Results further revealed that, in line with theoretical expectations, the THIS were positively related to motivational belief (value belief and expectancy belief), homework behavior (effort, management, and completion), and math achievement.     

An interspecies computational study on limb lengthening

Distraction osteogenesis is a surgical technique that produces large volumes of new bone by gradually separating two osteotomized bone segments. A previously proposed mechanical-based model that includes the effect of pre-traction stresses (stress level in the gap tissue before each distraction step) during limb lengthening is used here. In the present work, the spatial and temporal patterns of tissue distribution during distraction osteogenesis in different species (sheep, rabbit) and in the human are compared numerically to predict experimental results. Interspecies differential characteristics such as size, distraction protocol, and rate of distraction, among others, are chosen according to experiments. Tissue distributions and reaction forces are then analysed as indicators of the healing pattern. The results obtained are in agreement with experimental findings regarding both tissue distribution and reaction forces. The ability of the model to qualitatively predict the two animal models and the human healing pattern in distraction osteogenesis indicates its potential in understanding the influence of mechanics in this complex process.     

MUSCLE FORCE MEASUREMENT SYSTEM FOR LONG-TERM MONITORING DURING DISTRACTION OSTEOGENESIS

Distraction osteogenesis is a procedure in orthopedics for skeletal lengthening. This operation sometimes causes clinical complications such as paralysis and pain related to the rate and extent of distraction. Therefore, a tension-force monitoring system is mandatory to control optimal lengthening. We developed a portable, low-power consumption system to continuously monitor the distracted tensions during the distraction osteogenesis period on the tibias of four male New Zealand white rabbits. The lengthening rate was 1mm per day at frequencies of once a day in one rabbit, and of three successive steps in the others. The system indicates the distraction measured by force, which is considered to be more physiological in nature rather than by distance. Radiographs were also taken for comparison. The results showed that the system was stable and approximate to being ideal. The measured distract-tension recovered to a steady state faster at the frequency of 1mm a day in three steps, rather than once per day. During the duration of the entire operation, each single lengthening induced more extensive force than that of one-day totals. The integer tension gradually increased until 15 days and tended to be stable. The radiographic examinations also revealed that the tibias healed well after the lengthening; consequently, a dispensable X-ray might be mostly replaced by the system monitoring. This system might be helpful to monitor force measurement for the improvement of distraction osteogenesis.     

Investigating the reliability and validity of the Multidimensional Emotional Empathy Scale

The aim of the present study was to investigate the reliability and validity of the Multidimensional Emotional Empathy Scale (MDEES). Using a sample of British young people, we investigated the reliability of the scale, as well as the convergent and divergent validity with standardized measures of IQ and working memory. There was good internal consistency between the items in each subscale. With respect to validity, only the Emotional Suffering and Positive Sharing subscales were significantly related to verbal IQ; no other MDEES subscales were significantly associated with nonverbal IQ or working memory. The findings also suggest that the MDEES is a reliable and valid measure of emotional empathy and captures skills distinct from IQ and working memory.     

A study of the cracking sounds from the metacarpophalangeal joint

The familiar cracking sounds produced by distraction of the metacarpophalangeal joints were studied using accelerometers and a computerized signal analysis system. The joints were distracted in a controlled manner using a motorized device which simultaneously monitored the load on the joint and its extension. The load and extension parameters and those from the signal analysis were used to examine diurnal variation, the effects of multiple distractions, distraction speed, hand temperature and loading between distractions, and to show that in many cases, the energy contained in a crack signal, expressed as a ratio of the articular cartilage volume, exceeded a known level needed to produce articular cartilage damage.     

检测水中含油浓度的传感器研究

】根据光的散射规律和水中含油浓度的检测特点,论述了水中含油浓度检测传感器和水中含油浓度的测量电路的设计原理和工作原理,提出了检测传感器设计中的若干关键性技术问题的解决方法和几个管理要点。     

A study of the validity and reliability study of the homework purpose scale: A psychometric evaluation

This paper describes the initial psychometric evaluation of the Homework Purpose Scale (HPS), taking an illustration form practice in one country where it is used. The Homework Purpose Scale was designed to measure homework purpose. Both exploratory and confirmatory factor analyses were performed on samples of undergraduate students (N = 443). Results showed that the factor structure of the Turkish version of the HPS (where the study was carried out) was largely similar to the original one in the US. Moreover, each subscale demonstrated high internal consistency, and as predicted was correlated with theoretically related homework measures and other relevant constructs, along with displaying temporal stability. In brief, initial results indicate that the version of the HPS used here is a reliable and valid multidimensional measure for determining homework purpose.     

Impact of traffic environment and cognitive workload on older drivers’ behavior in simulated driving

As the use of in-vehicle technologies became more popular, there is concern about a concomitant increase in driver distraction arising from their use. While the introduction of voice recognition systems is intended to reduce the distraction due to manual operation of these units, a significant proportion of the distraction associated with their use may arise not from the manual manipulation but rather the cognitive consequences. It is also known that the risk of inattentive driving varies with age. In this study, the impact of cognitive workload and traffic environments on older drivers’ behavior was investigated in a driving simulator. To assess the impact of advancing age on driving performance degradation under a dual task condition, the performance of 63 drivers, divided into younger (20–29) and older (60–69) age groups, was evaluated. The authors also considered driving behavioral differences in the context of urban and highway driving, appropriately counterbalanced. At a specified location in the two scenarios, subjects were asked to complete a series of auditory tasks of increasing complexity. Comparisons of younger and older drivers’ driving performance, including forward velocity, speed control, standard deviation of lane position and steering wheel reversal rate, were conducted. Results indicated that age and traffic environment impact both driving performance and compensatory behavior during dual task conditions.     

教育与个人主义问题

人是自由的人，也是独立的人。无论对于个人、大学、还是民族，独立人格能保证自由思想，能自由思想是保有独立人格的主要表现。因此可以提出这样的“个人主义”：任何个人都是独立的自己，每个人都可发展，从而更富有、更智慧、更高大，而富有了的个人可以更多地贡献社会。教育中可以奉行这种个人主义：每个学生是每个学生自己；每个学生都有权发展和丰富自己：盼望发展了的学生能够有效地为自己的民族服务，为变革社会而努力。     

A heuristic threshold policy for fault detection and diagnosis in multivariate statistical quality control environments

In this paper, a heuristic threshold policy is developed to detect and classify the states of a multivariate quality control system. In this approach, a probability measure called belief is first assigned to the quality characteristics and then the posterior belief of out-of-control characteristics is updated by taking new observations and using a Bayesian rule. If the posterior belief is more than a decision threshold, called minimum acceptable belief determined using a heuristic threshold policy, then the corresponding quality characteristic is classified out-of-control. Besides using a different approach, the main difference between the current research and previous works is that the current work develops a novel heuristic threshold policy, in which in order to save sampling cost and time or when these factors are constrained, the number of the data gathering stages is assumed limited. A numerical example along with some simulation experiments is given at the end to demonstrate the application of the proposed methodology and to evaluate its performances in different scenarios of mean shifts.     

Application of the transmissibility concept in transfer path analysis

In recent years, there has been a renewed interest in developing faster and simpler transfer path analysis (TPA) methods. A dominant class of these new approaches, often referred to as Operational Path Analyses (OPA), is designed to achieve this goal by using only operational data in conjunction with the application of the transmissibility concept. Despite the reduction in measurement time and complexity, these suffer from a number of limitations, such as problems related to the estimation of transmissibility, or the unreliability of the results due to cross-coupling between path inputs, etc., which makes them prone to errors. Some of these only apply to one specific method, while others are common to all transmissibility based approaches. The goal of this paper is to identify and describe these limitations and point out the potential dangers of applying such methods without taking these into account.     

基于文化遗传算法求解柔性作业车间调度问题

在分析柔性作业车间调度问题特性的基础上,提出了一种采用主群体空间和信仰空间的双层进化结构的调度算法。该算法采用优良调度方案的知识信息构成信仰空间;提出一种二维矩阵的集成编码;基于工序顺序编码和基于机器分配编码的两种交叉和变异算子在主群体空间进行传统的遗传操作;通过具有自学习特点的相似性选择算子,使子代更好地继承父代的优良特征。通过典型算例的计算实验,表明算法在计算效率和求解质量上均具有较好的效果。     

假肢手恒定力量输出的诱发肌电反馈控制研究

肌电假肢手的连续动态控制有益于提高假肢手的使用性能和用户对假肢手的交互控制能力,产生持续稳定的力量是假肢手需要完成的一种常见任务,但是疲劳、注意力分散等诸多因素都可能导致肌电信号发生变化从而影响假肢手稳定力量输出。本文提出了一种基于电刺激诱发肌电的假肢手稳定力量输出控制方法,通过电刺激尺神经诱发肌电信号对假肢手恒定力量输出进行持续控制。为验证方法可行性,招募了7名健康被试,首先测试了稳定抓握过程中注意力分散对屈肌肌电活动水平的影响,并确定电刺激强度与诱发肌电(M波)幅度的关系模型;在此基础上,测试了电刺激在注意力分散过程中是否能诱发出预期的肌电信号。结果表明注意力分散会引起肌电信号幅度下降,通过电刺激方法可以得到恒定的肌电输出;同时,通过调节刺激参数可以控制诱发肌电强度,可为肌电假肢手的稳定力量输出提供有效的控制信号。     

A study of the fouling characteristics of EGR coolers in diesel engines

Diesel emission regulations have recently become more severe. An important goal in diesel engine research is the development of methods to reduce the emissions of NOx and PM (particulate matter). Cooled EGR (exhaust gas recirculation) system has been widely used to reduce the NOx and PM emissions of light-duty diesel engines. In this study, numerical analyses, rig tests and engine tests were performed to assess how changes in internal shape characteristics can improve the heat exchange efficiencies of EGR coolers. The heat exchange efficiencies of EGR coolers have been numerically and experimentally measured during a fouling process. The results show that the second type of oval EGR cooler tested (oval #2) exhibited better heat exchange efficiency than either the first type of oval EGR cooler was tested (oval #1) or the shell and tube cooler examined. The turbulence generated in exhaust gas flows by the wavy-finned design of the oval EGR coolers facilitated PM desorption that allows these coolers to self-purify. With respect to the two similar oval EGR coolers, the cooler with fin pitch 4 mm has better efficiency than the cooler with fin pitch 6 mm due to differences in the heat transfer areas of these coolers. Both CFD analyses involving extreme conditions of engine operation and engine fouling tests involving conditions experienced during vehicular operation indicate that the two oval coolers differed by less than 4% with respect to both initial heat transfer efficiency and heat transfer efficiency after a 78-hour fouling test.     

一种基于粗糙集和模式识别的旋转机械故障诊断方法

提出了一种基于粗糙集理论和模式识别的旋转机械故障诊断方法。该方法包括模式学习和模式匹配 2个过程 ,模式学习用粗糙集方法学习已知故障样本中的标准模式 ,即故障诊断规则 ,模式匹配把待诊断对象和标准模式进行匹配从而进行故障诊断。文中提出的学习方法考虑了样本中的重复对象和冲突对象 ,使获得的诊断规则能够覆盖所有的已知故障样本 ;在模式匹配时 ,根据条件匹配的程度、规则的置信度和诊断结论阈值获得诊断结论和结论置信度 ,从而使得到的结论更客观。最后通过实验验证了该方法的有效性。     

A new FMEA method by integrating fuzzy belief structure and TOPSIS to improve risk evaluation process

Failure mode and effect analysis (FMEA) model is a technique used to evaluate the risk. This paper aimed to propose a new FMEA model combining technique for order of preference by similarity to ideal solution (TOPSIS) and belief structure to overcome the shortcomings of the traditional index of FMEA. In this paper, the fuzzy belief TOPSIS method is combined with FMEA to introduce a belief structure FMEA to describe the expert knowledge by a number of linguists as a grammatical phenomenon. Moreover, the weights of components in FMEA index can be different from each other. Therefore, the flexibility of assigning weight to each factor in this method is more compatible to the real decision-making situation. In other word, TOPSIS method is applied to determine the preference of alternatives versus risk criteria. Using linguistic terms in the fuzzy belief approach, the risk factors described a more meaningful value and decision-makers’ judgment is assigned with belief degrees through evaluation of factors. Finally, a numerical case study about the preference of cause failures of steel production process is provided to illustrate the process of proposed method, and then result and discussion is performed for each case.     

Safety analysis of discrete event systems using a simplified Petri net controller

This paper deals with the problem of forbidden states in discrete event systems based on Petri net models. So, a method is presented to prevent the system from entering these states by constructing a small number of generalized mutual exclusion constraints. This goal is achieved by solving three types of Integer Linear Programming problems. The problems are designed to verify the constraints that some of them are related to verifying authorized states and the others are related to avoiding forbidden states. The obtained constraints can be enforced on the system using a small number of control places. Moreover, the number of arcs related to these places is small, and the controller after connecting them is maximally permissive.     

Effect of twisting hamstring tendon grafts on strength and joint laxity through the range of knee movement

Twisting or braiding of hamstring tendon grafts for use in anterior cruciate ligament reconstructions has been advocated to increase their strength and stiffness under load. In this study, a two-dimensional model was used to determine the failure strength of twisted and parallel grafts and associated knee laxity under simulated physiological loading conditions. For validation, mechanical tests of tendon grafts were also simulated with these models. The simulated physiological loading of the graft models showed that knees with twisted grafts had greater laxity than knees with parallel grafts, although there was little difference in failure load between the two graft configurations. The tensile loading of the graft models showed little difference in failure load when the tendons were modelled using line segments. When the tendons were considered as three-dimensional helical elements, which more accurately describe the tendon structure, the failure load of the twisted graft decreased significantly. This research provided no evidence to support the belief that a twisted tendon graft is a superior graft configuration relative to a parallel tendon graft.     

A method for the identification of hydraulic damper characteristics from steady velocity inputs

The research presented in this paper investigates the possibility of precise experimental identification of steady damper characteristics. The paper considers velocity sensitive and nominally symmetric hydraulic dampers. The proposed identification methodology is based on a piecewise constant velocity excitation. One goal of the paper is to analyze the transient nature of the damper response in the context of finite permissible piston displacements and first order transient effects due to elastic elements in the damper structure. The proposed methodology is formalized in a framework suitable for experimental design, allowing the detailed study of steady state damper performance. The second goal of the paper is to demonstrate the practical application of the proposed methodology. It is applied to the case of a safety critical hydraulic damper used for stability augmentation in production helicopters. The research work presented shows that this methodology can be used for identification in a finite but relatively wide range of piston velocities. The case study demonstrates a successful example of damper property identification where the resulting characteristics prove useful as a tool for model validation. Finally, the identification results are related to the results of a more traditional test with harmonic piston excitation.     

A mixed FEM and lumped-parameter dynamic model for evaluating the modal properties of planetary gearboxes

Planetary gearboxes are extensively used in mechatronic applications due to their compactness and high reduction ratios. The complex kinematic of such systems and the requirement of low-vibration-gears suggest studying these gearboxes with appropriate dynamic models. To this purpose, a planar lumped parameter model with 18 degrees of freedom was implemented. Model parameters such as the stiffness of the bearings and the gear meshes were calculated using dedicated FEM simulations. Two different gearbox configurations were simulated and experimentally tested. The compared results showed a good agreement. The main goal of the research was to assess the validity of such methodology for the prediction of the system eigenfrequencies. Additionally, from a kinematic analysis of the gearbox it was possible to individuate the self-excitation frequencies. The overlapping of these self-excited frequencies with the eigenfrequencies of the system was individuated as the major cause of the gearbox noise.