图象中可见水印的误差控制

Different digital watermarking techniques and their applications are briefly reviewed.Solution to a practical problem with visible image marking is presented,together with experimental results and discussion.Main focusis on reduction of error caused by the mark addition and subtraction.Image classification based on its mean gray level and adjustment of out-of-range gray levels are implemented.     

Impact case studies: what accounts for the need for numbers in impact evaluation?

ABSTRACT

The UK Research Excellence Framework (REF) introduced impact as an indicator in the evaluation of higher education research quality in 2014. Impact case studies (ICS) are the basis of this evaluation. ICS use narrative explanations of how research causes ‘benefits to society’. This article analyses the evolving roles of the ICS and the relationships of ICS with various stakeholders. It draws on insights from legitimacy theory, Porter’s analysis of the social meaning of objectivity, and the insight from economist Alan Goodhart on the dysfunctional transformation of indicators into targets. It highlights the challenges to ICS evaluators and shows how a spiral of mistrust can both undermine but also cause demand for numbers. It explores whether impact narratives represent an escape from dominant research evaluation metrics and concludes that they do not.     

Relationship of play and language patterns among Singaporean pre‐school children in homes and classrooms

This paper reports the findings of a study aimed at investigating the relationship between Singaporean preschool children's play and language patterns. Observations of 56 children (aged between 4.0 and 6.0 years) from middle and lower‐middle income families at play in a standardised setting in their classrooms and in their homes were videotaped and analysed using two play measures and five language measures. Analysis of parental data revealed positive attitudes towards child play and high involvement in children's play. High Caldwell HOME scores revealed homogeneity in home environments for stimulating child learning and cognitive development. Few significant differences as a function of age, sex or SES were found. Correlational data demonstrated the utility of specific play and language measures. Higher levels of play and higher levels of language were correlated.     

Teaching Integration: How Certain Instructional Moves May Undermine the Potential Conceptual Value of the Riemann Sum and the Riemann Integral

Past research in calculus education has shown that Riemann sum-based conceptions of the definite integral, such as the multiplicatively based summation (MBS) conception, can have important value in interpreting and making sense of certain types of definite integral expressions. However, additional research has shown that students tend to not draw on the MBS conception, even in situations where it would be advantageous to do so. In this study we examine how introductory instruction on integration, in which explicit attention is given to the Riemann sum and Riemann integral, may be related to students’ tendency to not use the MBS conception. In particular, it appears that some calculus instructors may make instructional moves in their classrooms that directly undermine the time the instructors had spent developing the Riemann sum and Riemann integral concepts. In doing so, students may perceive these concepts only as calculational procedures, rather than as a potential source of conceptual meaning.     

Research Report RECSAM: Computers in Education Project,Singapore Study

From 1986 to 1988, Regional Centre for Education in Science and Mathematics (RECSAM) at Penang organised the Computers in Education Project with financial support from the Australian Government. The aim of the Project was to provide information on the use of computers in education among SEAMEO countries. Such information, it was thought, could be useful for educators who needed to formulate sound policies regarding the introduction, management, and use of computers in schools and the roles of computers in education in general. Six countries took part in this project including a team from Singapore.     

Effects of consistency and adequacy of language information on understanding elementary mathematics word problems

Two types of elementary mathematics word problems involving different linguistic structures were devised to examine the understanding and solution of these problems by 91 Grade 3, 4, and 5 children divided into “more able” and “less able” subgroups. One task consisted of 12 consistent and 12 inconsistent language problems on the basic processes of addition, subtraction, multiplication and division. Another task consisted of a total of 36 word problems with 12 items each containing adequate, inadequate, and redundant information, respectively, for problem solution. Subsidiary tasks of general ability, vocabulary, reading comprehension, mathematics concepts, reflection on mathematics learning, and working memory were also administered to provide estimates of the contribution of these “nonmathematics” tasks to the solution of elementary mathematics problems. Analyses of variance and covariance of group data showed significant main effects of grade, consistency, and adequacy of linguistic information in problem solution. Word problems containing inconsistent information were more difficult than those with consistent information. Further, word problems containing inadequate and redundant information were more difficult to classify, and for the children to explain, than those items with just enough information. Interviews with 12 individual children provided further insight into their strategies for problem solutions. Both cognitive and developmental perspectives are important for mathematics learning and teaching for children with or without learning disabilities.     

波普尔科学方法论对高校工科教学改革的启迪

通过对波普尔科学方法论的认识，探讨该思想对高校工科教学改革的启示，指出其假说模式对于培养高校创新型人才的积极意义，结合教学实践给出了教学改革的几点建议。     

Practicum teachers’ use of mobile technology as measured by the technology acceptance model

ABSTRACT

This study utilized the Technology Acceptance Model (TAM) to examine practicum teachers’ current use of mobile technology and their intentions of use in the future. A survey was conducted to better understand the relationship between practicum teachers and their potential assimilation of technology into classroom practice. The survey questionnaire was administered to 100 undergraduate students at [institute withheld], [country withheld]’s teacher preparatory university. The following four key constructs of the TAM were assessed: perceived ease of use (PEU), perceived usefulness (PU), subjective norm (SN), and behavioural intention to use (BIU). The impact of practicum teachers’ gender and academic subjects on their acceptance of technology were also investigated. The present study found strong links between PEU and PU. While practicum teachers perceived mobile technology as being useful and intended to use it in their classrooms, BIU was not significantly impacted by PEU, PU, or SN. The data also suggested that gender did not affect BIU while practicum teachers’ academic subjects might be an indicator of their future intentions to use mobile technology. With these findings, recommendations are made to further improve the integration of mobile technology in classroom practice.     

Scaling up of Continual Professional Development for Mathematics Problem Solving in Singapore Schools

The more ambitious an educational innovation, the greater the challenge in scaling up. In this paper, we focus on the scaling up of an ambitious pedagogical practice—mathematics problem solving as a regular feature in the classroom. We adopt a long-term approach to continual professional development (CPD) that began with intensive work with one school before we broadened the programme to four other schools which span the spectrum of schools in Singapore. To evaluate this overall design, we examine the current state of each school’s capacity in sustaining mathematics problem-solving instruction. In particular, we study and report findings on these areas: the readiness of teachers, the instructional materials and supporting structures. Based on the findings, we reflect on our CPD strategies and our theory of action which guided the CPD programme.