Designing a LOGO-based microworld for ratio and proportion

Abstract This paper reports the results of the first part of a study to design, implement and evaluate a LOGO -based microworld for ratio and proportion. The microworld provided pupils (of 12 -13 years-of-age) with pre-written LOGO tools which could be used and explored in terms of their internal and external relationships; pupils were given opportunities to create and explore their own programs. The microworld was implemented in a class of 24 children with the researchers acting as teachers. Evaluation took the form of (i) paper-and-pencil pre- and delayed post-tests; (ii) audio recorded interviews with nine pupils subsequent to both tests; (iii) process data during the microworld implementation.     

Ways of learning in a computer-based environment: some findings of the LOGO Maths Project

Abstract  This paper is derived from the LOGO Maths Project's investigation of the potential of LOGO in the secondary school mathematics classroom (1983–1986). The main focus of the work has been to discover whether and under what conditions the computer language LOGO can be used as an aid to pupils' learning and thinking in mathematics. Longitudinal case studies were undertaken for four pairs of pupils throughout the three years of the project. In addition the research was extended for two years into another eight schools. This paper presents the findings concerned with peer collaboration and the role of the teacher in the LOGO environment. It describes how LOGO work can be used to gain insights into pupils' conceptions of mathematical ideas. It also makes reference to gender issues in the wider context of computer use in the United Kingdom.     

The impact of LOGO on gifted children's achievement and creativity

It was hypothesised that problem solving via the Arabic logo programming environment would enhance gifted children's mathematics achievement and their creativity as measured by their performance on Torrance Tests of Creative Thinking (TTCT) and Mathematical Skills Assessment (MSA). The study findings extend previous research by indicating that problem solving via the LOGO programming environment can enhance mathematics achievement and creativity in figural, as well as verbal, domains. The evaluation of a large number of previous studies on the enhancement of creativity concluded that many of these studies have a positive effect. An implication is that computer environments may offer appropriate special provisions to meet the special needs of gifted children. In addition, this experiment provided some evidence that if gifted children work in pairs the need for teacher intervention to motivate the children is decreased. Also, if gifted children choose their own goals this increases their motivation and task commitment but might also restrict the range of mathematical ideas used.     

An analogue and propositional hybrid model for the perception of computer generated graphical images

This research investigated two alternative models, analogue and propositional, which describe how three-dimensional (3-D) graphical images are represented and stored in human memory. In order to differentiate between the two models, three separate experiments were performed using a variation of the Shepard-Metzler mental rotation paradigm (Shepard and Metzler 1971). For each experiment, the effects of three independent variables on the performance of a 'mental rotation' task were examined: (a) three levels of figure complexity, ( b) three axes of rotation and (c) four angles of rotation. The subjects' task was to compare specific angle, axis or depth versus picture plane rotations for pairs (rotated and non-rotated versions) of 3-D graphic figures displayed on a CRT. The results indicated that response times varied depending on level of figure complexity, axis or angle of rotation. A new hybrid model integrating components of both the analogue and propositional positions is proposed to explain the reaction time data. In this model, analogue processes occur when processing requirements for cognitive tasks are low, whereas propositional processes occur when processing requirements are high. Implications of the results for the internal representation of 3-D images in human memory and for the design of graphic work stations are discussed.     

An investigation of Year 7 pupils learning CONTROL LOGO

Abstract Recommendations for the IT component of the National Curriculum suggested that Key Stage 2 pupils use "IT to control models such as level crossing barriers and traffic lights". This paper describes a 3-year investigation into the use of CONTROL LOGO (and languages with a similar syntax) for control technology in Year 7. It was found that most pupils were able to program simple control sequences using meaningful labels and procedures and that LOGO did assist the acquisition of good programming habits. However, particular difficulties with the LOGO syntax were noted when inputs were being used, and it was concluded that LOGO is unsuitable for this particular purpose.     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

An analogue and propositional hybrid model for the perception of computer generated graphical images

Abstract

This research investigated two alternative models, analogue and propositional, which describe how three-dimensional (3-D) graphical images are represented and stored in human memory. In order to differentiate between the two models, three separate experiments were performed using a variation of the Shepard-Metzler mental rotation paradigm (Shepard and Metzler 1971). For each experiment, the effects of three independent variables on the performance of a ‘mental rotation’ task were examined: (a) three levels of figure complexity, ( b) three axes of rotation and (c) four angles of rotation. The subjects' task was to compare specific angle, axis or depth versus picture plane rotations for pairs (rotated and non-rotated versions) of 3-D graphic figures displayed on a CRT. The results indicated that response times varied depending on level of figure complexity, axis or angle of rotation. A new hybrid model integrating components of both the analogue and propositional positions is proposed to explain the reaction time data. In this model, analogue processes occur when processing requirements for cognitive tasks are low, whereas propositional processes occur when processing requirements are high. Implications of the results for the internal representation of 3-D images in human memory and for the design of graphic work stations are discussed.     

Light-actuated water droplet motions on ZnO nanorods

Water droplets were either pushed or pulled with an ultra-violet (UV) light on vertically aligned ZnO nanorods. Steric acid-immobilized ZnO nanorods grown on quartz substrates exhibit a hydrophobic surface possessing high contact angles between water droplets and the substrates. Exposure of UV onto droplets on ZnO NRs led to reduction of contact angles and resulted the internal circulating flows inside the droplets. Droplets located at different sites under the spot of the UV light created different magnitudes of contact angle changes and the internal circulating flows which allowed us to push the droplets away or pull the droplets toward the centre of the UV spot.     

Inversion of the Baseline Incline Angle for Tiangong-2 Interferometric Imaging Radar Altimeter

Tiangong-2 Interferometric Imaging Radar Altimeter(InIRA) is the first wide-swath radar altimeter adopting small incidences angles with short baseline.The knowledge of the roll angle of the baseline is crucial for measuring the wide-swath Sea Surface Height(SSH) with centimeter-level accuracy.In this work,we aim to validate the technique of baseline angle determination from spaceborne nadir interferometric echoes which has been tested by airborne experiment.According to the observation geometry,the interferometric phases of nadir echoes acquired by Tiangong-2 Imaging Radar Altimeter(InIRA) are related to the roll angle of the baseline,so it should be possible for us to retrieve the incline angle from the interferometric phases under some ocean conditions not so high.In order to do so,the Tiangong-2 was tilted about 5° so as to realize a 0° baseline and in this way,a lot of data was collected.In this paper,we present the retrieved roll angles and compare them with the measured angles by the platform.Due to the Earth is an ellipsoid,and the control of the Tiangong-2 is referring to the Earth center,while the retrieved roll angle is referring to the nadir point on the Earth surface,there is a systematic error related to the orbit,and after calibration of which,the expected results are obtained：two measurements agree with each other very well not only for the measured trend but also for the standard bias between them.     

基于西门子LOGO!的洗衣机自动控制系统设计

西门子LOGO!是介于PLC和继电器之间的可编程逻辑控制器,它适应控制技术市场细分的趋势,简单灵活,易于设计、维护。采用西门子LOGO!作为全自动洗衣机的控制器,对整个系统进行了创造性的设计,方便了职业教育的控制技术教学,也为LOGO!步入洗衣机控制领域做出了有益的尝试。     

基于Web2.0的《网络技术与实践》课程网站的设计与实现

随着计算机网络的发展,网页上的交互性大大增强,本文基于ASP.NET2.0设计实现了<网络技术与实践>的网络课程网站,培养了学生的自主学习能力和创新精神,加强了师生互动.其中的在线实验室24小时开放,学生在校园内随时随地在校园任何一个地方都可以通过校园网络登录在线实验室,进行组网技术的学习.     

多人网络虚拟现实儿童科普系统的设计研究

针对传统儿童科普教育存在的沉浸感薄弱、知识传输方式单一的问题,设计基于多人网络虚拟现实(VR)技术的儿童科普系统.系统的设计采用模块化的构建方式,主要分为网络联机模块和虚拟现实科普教育业务控制模块.在网络联机模块中,建立起服务器,教师机,学生机之间的信息通信,实现多人信息的加载和多人空间位置的实时同步.虚拟现实科普教育...     

Logo building blocks: Student teachers using computer-based mathematics apparatus

We describe experiments in which student teachers, who have been identified by their college of education as needing mathematical help, undertook a computer-based elementary maths course. Our objectives were to assess the effect of this work on the students' mathematical performance and attitude.The students were given hands-on experience of the programming language LOGO, which included both writing simple programs and running pre-defined procedures, such as those for illustrating the multiplication of fractions pictorially. The computer was used as a piece of mathematics apparatus with which the students could experiment: it did not take any tutorial or managerial role.A variety of mathematics performance and attitude tests were administered pre and post, and the results are described and analysed. Some evidence for the success of the approach is shown, though the experiments underline the enormous difficulty of helping this kind of student.     

Investigating the impact of an integrated approach to the development of preservice teachers' technological pedagogical content knowledge (TPACK)

The purpose of this study is to describe an integrated pedagogical approach, aimed at advancing preservice teachers' learning on the use of technology and investigate its impact on participants' knowledge (i.e., TPACK) and practice. The integrated approach juxtaposes an educational technology course with methods courses and field experience through careful instructional design. Both quantitative and qualitative data were collected. Quantitative data were collected through a pre-post administration of the Survey of Preservice Teachers' Knowledge of Teaching and Technology. Qualitative data were collected through open-ended survey responses and preservice teacher case narratives reporting on the design and implementation of technology-integrated lessons in a field placement. Finding revealed that participants experienced significant gains in all TPACK constructs. Further, findings indicated that participants applied their knowledge in practice though there was variability in the ways in which knowledge domains were represented in participants' narratives. Findings have implications for teacher education programs and for researchers interested in the development and assessment of preservice teacher knowledge of teaching with technology.     

The strategies and interactions of young children in LOGO tasks

Abstract  The present study analysed the strategies and interactions of 60 7-year-old children working on LOGO tasks in gender pairs (girls, boys and boy/ girls). The results revealed that initially there were significant differences on some performance variables, based on gender, in one of the tasks. However, these disappeared when the task was changed to one with a focus on accuracy. By the end of the study differences in performance were found to be associated with the application of higher order strategies for problem-solving. The research investigated the nature of the early differences between the groups by examining the strategies and interactions of the pairs of children. The study highlights the importance of considering both the type of task and performance over a reasonable period of time when describing the nature and extent of young children's learning when problem solving in a novel environment.     

基于斜投影及先验信息的波达方向估计算法

提出一种应用于正交频分复用智能天线系统中的波达方向估计算法。该算法利用实际环境中基站与周围建筑物之间已知的角度信息,基于MUSIC算法的最小二乘思想,引入斜投影算子估计未知角度。理论和仿真实验证明,该算法是对未知角度的无偏估计,适用于分辨与已知角度相差很小的未知角度值,较传统的MUSIC算法有明显优势。     

Turtle geometry in computer graphics and computer-aided design

LOGO is a programming language incorporating turtle graphics, originally devised for teaching computing to young children in elementary and middle schools. Here, we advocate the use of LOGO to help introduce some of the basic concepts of computer graphics and computer-aided design to undergraduate and graduate students in colleges and universities. We shall show how to motivate affine coordinates and affine transformations, fractal curves and iterated function systems, relaxation methods and subdivision schemes from elementary notions in turtle geometry and turtle programming.     

Estimation of skew angles for scanned documents based on piecewise covering by parallelograms

We propose a fast and robust skew estimation method for scanned documents that estimates skew angles based on piecewise covering of objects, such as textlines, figures, forms, or tables. The method first divides a document image into a number of non-overlapping slabs in which each object is covered by parallelograms. It then estimates the skew angle based on these parallelograms or, equivalently, their complementary regions. Putting our method to a systematic test and comparing it with some alternatives, we find that it yields favorable results in terms of accuracy, sensitivity to non-textual objects, effectiveness in dealing with documents of unspecified reading order, and computational efficiency. Some work is also conducted to find an effective way to further shorten its computation time at the expense of an extremely small loss of accuracy.