Significant correlation between school myopia and postural parameters of students while studying

This study examined the posture of young students while studying and its relation to the degradation of naked vision. Subjects were 19 young students (mean age=13.2±2.2 yr). The posture while studying was quantitatively analyzed, along with a comparison made with visual functions. The subjects' posture was monitored from the front and lateral views using a video camera. The parameters were viewing distance (cm), neck angle (degree), vertical gaze direction (degree) and viewing angle (degree). Each parameter was measured by frame analysis of the video images. A significant relationship arose between the viewing distance and eye accommodation (diopter), near point (cm), viewing angle and neck angle (p<0.01). Based on the results presented herein, we can conclude that poor posture, particularly decreased neck angle, is significantly related to the degradation of naked vision.Relevance to industryThis study examined the ergo-ophthalmological problem of posture of young students while studying. Because of the difference of height and weight between young students and adults, there is a possibility of bad influence on the posture of young students when using VDT. This awareness has caused concern for product liability of VDT workstations in its developers.     

Influence on the propulsive performance due to the difference in the fin shape of a robotic manta

This paper experimentally investigates the influence on the propulsive performance by the difference in the fin shape of a robotic manta. Five kinds of fin shapes, i.e., a rectangle, a triangle, a trapezoid, and two right triangles, are used in experiment to measure the forward speed of the robot, where two types of right triangle are discriminated, depending on the arrangement of the right angle part and each fin area is assumed to be approximately equal, and the number of fin rays is the same at all the fins. It is proved that a significant difference in propulsive speed arises depending on the difference in the fin shape. Some experiments are additionally conducted to examine the influence on the propulsive speed and its efficiency, due to the parameter change of a progressive wave in the fin.     

ZSM5-Y型分子筛催化剂复配体系裂化性能数值研究

采用流动和反应耦合模型模拟ZSM5-Y复配催化剂体系在提升管反应器内的催化裂化过程。结果表明,重油催化裂化反应主要发生在喷嘴附近,该处有45%的重油转化为汽油和柴油。对于ZSM5-Y型复配催化剂体系,ZSM5加入沸石催化剂的显然影响着汽油和液化气的产率,反应产物中柴油馏分及重油馏分的产率基本上不受影响。加入少量择形催化剂便大大降低提升管反应器汽油馏分收率,并提高液化气收率,但汽油与液化气产率显著变化仅发生在择形催化剂加量较小的时候,一旦超过10%以后,对气油和液化气的产率影响反而较小。     

Is a schools’ performance related to technical change? – A study on the relationship between innovations and secondary school productivity

This paper examines the relation between innovations and productivity in Dutch secondary schools. Innovation clusters are directly included in the production model. In order to correct for differences between schools, we add school type, region and year controls. The results indicate that process innovations, teacher professionalization innovations and education chain innovations are positively related to productivity, whereas new courses innovations and pedagogic innovations are negatively related to productivity. The results also show that innovations are directly related to productivity, but also through student performance. The positive results of teacher professionalization, education chain and process innovations are similar to what is found elsewhere in the literature.     

A correlation study between automated program repair and test-suite metrics

Automated program repair is increasingly gaining traction, due to its potential to reduce debugging cost greatly. The feasibility of automated program repair has been shown in a number of works, and the research focus is gradually shifting toward the quality of generated patches. One promising direction is to control the quality of generated patches by controlling the quality of test-suites used for automated program repair. In this paper, we ask the following research question: “Can traditional test-suite metrics proposed for the purpose of software testing also be used for the purpose of automated program repair?” We empirically investigate whether traditional test-suite metrics such as statement/branch coverage and mutation score are effective in controlling the reliability of generated repairs (the likelihood that repairs cause regression errors). We conduct the largest-scale experiments of this kind to date with real-world software, and for the first time perform a correlation study between various test-suite metrics and the reliability of generated repairs. Our results show that in general, with the increase of traditional test suite metrics, the reliability of repairs tend to increase. In particular, such a trend is most strongly observed in statement coverage. Our results imply that the traditional test suite metrics proposed for software testing can also be used for automated program repair to improve the reliability of repairs.     

MMORPGS and cognitive performance: A study with 1280 Brazilian high school students

The present paper attempts to empirically study the cognitive impacts of Massive Multiplayer Online Role-Playing Games (MMORPGs) in uncontrolled contexts in light of the Cognitive Mediation Networks Theory, a new model of human intelligence that aims to explain cognition as the result of brain activity combined with the information-processing done by external structures such as tools, social groups and culture. A sample of 1280 students Brazilian high school students answered a form inquiring about socio-demographic information plus the use of computer games, and also was submitted to a short knowledge exam and a mini psychometric test. The findings indicated that, due to their underlying structure and sociocultural nature, MMORPGs are associated to a greater level of insertion into the Digital Age, higher levels of logical-numerical performance, and better scholastic ability. Finally, suggestions are made for future studies on the subject.     

A study of academic performance of business school graduates using neural network and statistical techniques

Over the past several years, there is tremendous increase in the number of applicants to business schools and hence adequately measuring the potential of these students with regard to their academic performance is an important process of admission decision for any business school. In the present study, an analysis is carried out to predict the academic performance of business school graduates using neural networks and traditional statistical techniques and results are compared to evaluate the performance of these techniques. The underlying constructs in a traditional business school curriculum are also identified and its relevance with the various elements of admission process is presented.     

Web服务QoS与用户位置的相关性实证研究

如何为用户准确预测Web服务的QoS是最近的一个热点研究问题.考虑到Web服务的QoS可能受用户具体位置的影响,一些工作提出了位置感知的Web服务QoS预测方法.然而,很少有工作在实践中针对Web服务QoS与用户位置的相关性进行具体验证.提出了一套对Web服务QoS与用户位置的关系进行验证的方法,并使用真实的Web服务QoS数据集进行了实验.实验与分析发现:用户位置越邻近,他们在相同Web服务上观察到的QoS越相似;反过来也是如此.这些结果表明Web服务QoS与用户位置之间具有较强的相关性,可以为位置感知的Web服务QoS预测方法提供很好的依据.     

A study of a modified VDT-stand arrangement

Abstract

The aim of this study was to establish an optimal keyboard and data space arrangement for data-entry operators using a VDT. The location of the keyboard and data was investigated in two ways:

(1) An experimental model with a straight-line arrangement of operator, keyboard, data to be entered and screen. Entry data in that model were located between the keyboard and the screen, on a special inclined support. A sliding ruler, making reading easier, was an additional piece of equipment of the support. The keyboard was placed in front of the desk, below its surface.

(2). A traditional model with a lateral arrangement of operator, keyboard, screen and with data to be entered either on the right or on the left of the keyboard.

The test carried out to compare the two arrangements proved the assumption that there is a difference in operators’efficiency depending on the type of arrangement used. While operating the straight-line VDT stand operators were more efficient than when using the lateral one and found the former arrangement more comfortable.     

Media composition and narrative performance at school

Abstract  POGO is a distributed learning environment that allows children to create stories by connecting physical and virtual worlds. The environment is composed of several interactive tools that children use to compose, edit and perform stories. Together with teachers, five pedagogical objectives were defined as goals to be achieved in narrative. The pedagogical objectives drove the entire POGO design process and constituted a solid reference for the different evaluations undertaken during the project. This paper, after a brief introduction and a presentation of the POGO world, illustrates how the interaction with the POGO Tools supports the fulfilment of the pedagogical objectives.     

Fractal evaluations of fish school movements in simulations and real observations

Fish schools behave like a single organism, and this offers considerable survival advantages. In our simulations, a fish school is well organized, without a leader, and behaves like a single creature depending solely on the interactions among individuals. This kind of system can be said to be typical of “complex systems.” In this article, it is shown that fractal evaluation is useful to understand the features of fish school movements. We make clear the validity of fractal analyses to quantify fish school movements through evaluations of simulated fish school movements andsardine movements. These fractal analyses show that we need two different fractal dimensions (D ₁,D ₂) to understand the features of fish school movements:D ₁ corresponds to thesmaller coarsening levels, andD ₂ corresponds to thelarge coarsening levels. The linear analyses in log-log space give an excellent fit with both the simulated movements and the sardine school movements. In approaching complex systems or complex behaviors, fractal analyses have attracted wide attention in mathematics, physical sciences, and information science. The fractal evaluations here convince us that we are coming close to understanding the structure of complex movements of animals. This work was presented, in part, at the Sixth International Symposium on Artificial Life and Robotics, Tokyo, Japan, January 15–17, 2001     

基于背部轮廓相关系数算法的淡水鱼种类识别研究

针对淡水鱼种类的自动识别问题,利用机器视觉技术,提出一种基于鱼体背部轮廓相关系数算法的鱼体种类识别方法。首先根据采集的鲫、草鱼、鳊、鲤四种淡水鱼图片,将图像处理方法应用到鱼体背部轮廓的提取上,并采用最小二乘算法对鱼体背部轮廓进行曲线拟合,建立这四种淡水鱼的背部轮廓数学模型;接着对要识别的鱼体,通过机器视觉技术获得鱼体轮廓,并计算提取的鱼体轮廓与建立的四种鱼背部轮廓数学模型的相关系数值,达到对鱼体种类自动识别目地;最后采用提出的方法对市场随机选取的各60条活鱼进行了测试,测试结果表明,该算法简单,识别准确率较高,能够为淡水鱼种类识别方法提供新的思路,提高水产养殖的自动化水平。     

Numerical study of interference between simple-shape bodies in hypersonic flows

Hypersonic rarefied-gas flows near two side-by-side plates and cylinders, toroidal balloon, plate and cylinder over a plane surface, and plate behind a cylinder in argon, nitrogen, oxygen, and carbon dioxide have been studied numerically using the direct simulation Monte-Carlo technique under the transition flow conditions at Knudsen numbers from 0.004 to 10. Strong influences of the geometrical factor (the ratio of a distance between bodies to a body length) and the Knudsen number on the flow structure about the bodies (shock-wave shapes, the configuration of subsonic flow zones), skin friction, pressure distribution, lift, and drag have been found.     

On the correlation between size and metric validity

Empirical validation of code metrics has a long history of success. Many metrics have been shown to be good predictors of external features, such as correlation to bugs. Our study provides an alternative explanation to such validation, attributing it to the confounding effect of size. In contradiction to received wisdom, we argue that the validity of a metric can be explained by its correlation to the size of the code artifact. In fact, this work came about in view of our failure in the quest of finding a metric that is both valid and free of this confounding effect. Our main discovery is that, with the appropriate (non-parametric) transformations, the validity of a metric can be accurately (with R-squared values being at times as high as 0.97) predicted from its correlation with size. The reported results are with respect to a suite of 26 metrics, that includes the famous Chidamber and Kemerer metrics. Concretely, it is shown that the more a metric is correlated with size, the more able it is to predict external features values, and vice-versa. We consider two methods for controlling for size, by linear transformations. As it turns out, metrics controlled for size, tend to eliminate their predictive capabilities. We also show that the famous Chidamber and Kemerer metrics are no better than other metrics in our suite. Overall, our results suggest code size is the only “unique” valid metric.     

Display-control compatibility: the relationship between performance and judgments of performance

This study examined whether people can judge the usability of display-control mappings. Participants identified one of two alternatives which were presented in a questionnaire. Several types of stimuli were tested, ranging from simple shapes to semantic stimuli. Choices were found to be predominately correct when usability was defined by an unambiguous spatial relationship between displays and controls. In contrast, estimates were less accurate for items which did not solely rely on spatial congruence. The findings were interpreted in terms of the factors that need to be considered for judgments to be free of error.     

Display-control compatibility: the relationship between performance and judgments of performance

This study examined whether people can judge the usability of display-control mappings. Participants identified one of two alternatives which were presented in a questionnaire. Several types of stimuli were tested, ranging from simple shapes to semantic stimuli. Choices were found to be predominately correct when usability was defined by an unambiguous spatial relationship between displays and controls. In contrast, estimates were less accurate for items which did not solely rely on spatial congruence. The findings were interpreted in terms of the factors that need to be considered for judgments to be free of error.     

Applying computer stereovision algorithms to study of correlation between face asymmetry and human vision pathology

Problem of human vision pathology diagnostics is being studied with the aid of computer vision technology. Hardware-software complex developed for this research is described. Several face asymmetry evaluation algorithms are analyzed. Relationship between asymmetry measure and medical diagnosis data is investigated.     

Assessing the performance of normal-based and REML-based confidence intervals for the intraclass correlation coefficient

Using normal distribution assumptions, one can obtain confidence intervals for variance components in a variety of applications. A normal-based interval, which has exact coverage probability under normality, is usually constructed from a pivot so that the endpoints of the interval depend on the data as well as the distribution of the pivotal quantity. Alternatively, one can employ a point estimation technique to form a large-sample (or approximate) confidence interval. A commonly used approach to estimate variance components is the restricted maximum likelihood (REML) method. The endpoints of a REML-based confidence interval depend on the data and the asymptotic distribution of the REML estimator. In this paper, simulation studies are conducted to evaluate the performance of the normal-based and the REML-based intervals for the intraclass correlation coefficient under non-normal distribution assumptions. Simulated coverage probabilities and expected lengths provide guidance as to which interval procedure is favored for a particular scenario. Estimating the kurtosis of the underlying distribution plays a central role in implementing the REML-based procedure. An empirical example is given to illustrate the usefulness of the REML-based confidence intervals under non-normality.