171,826 research outputs found

    Introductory programming: a systematic literature review

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    As computing becomes a mainstream discipline embedded in the school curriculum and acts as an enabler for an increasing range of academic disciplines in higher education, the literature on introductory programming is growing. Although there have been several reviews that focus on specific aspects of introductory programming, there has been no broad overview of the literature exploring recent trends across the breadth of introductory programming. This paper is the report of an ITiCSE working group that conducted a systematic review in order to gain an overview of the introductory programming literature. Partitioning the literature into papers addressing the student, teaching, the curriculum, and assessment, we explore trends, highlight advances in knowledge over the past 15 years, and indicate possible directions for future research

    An impulsive noise analyser using amplitude probability distribution (APD) for broadband-wired communication

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    Electromagnetic interference or noise which is of impulsive nature is known to affect data communication performance. It is useful to correlate the characteristics of the noise with the bit error probability (BEP). The amplitude probability distribution (APD) has been proposed within CISPR for characterisation of the impulsive noise. However, there is no analyser available to perform direct measurement of the noise within the bandwidth of asymmetric digital subscriber line (ADSL2+) communication. This research presents a novel development of APD analyser for measurements of impulsive noise emission and its impact on ADSL2+ communication. A unique noise APD pattern is obtained from each measurement of noise emission from different electrical and electronic appliances. It is vital to have correct measurement set-up, signal power level, sampling rate, sample points and filter characterisation in order to acquire accurate data representation of the noise patterns. The APD graph is generated by the analyser using the APD algorithm method which employs the envelope sampling technique from actual probability. The noises are characterised using α-stable distribution which exhibits its own distinct APD parameters. The APD curve can be related with the single modulation scheme communication channel performance for estimation of bit error probability. The analyser has been developed successfully with dynamic range of 70 dB higher than the 60 dB CISPR 16 requirement, 0.02 dB amplitude resolution compared to 0.25 dB CISPR 16 requirement and 0.59 dB amplitude accuracy compared with the CISPR 16 standard of +/- 2.7 dB. In addition, the limits for noise in copper cable have been proposed for estimating the severity of the interference towards digital communication performance in ADSL2+ system. An advantage of the analyser is its ability to not only record the noise but the ability to regenerate back the noise which can be used for further analysis. In conclusion, the analyser can provide a comprehensive platform for impulsive noise interference verification towards ADSL2+ communication performance

    A systematic review of protocol studies on conceptual design cognition: design as search and exploration

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    This paper reports findings from the first systematic review of protocol studies focusing specifically on conceptual design cognition, aiming to answer the following research question: What is our current understanding of the cognitive processes involved in conceptual design tasks carried out by individual designers? We reviewed 47 studies on architectural design, engineering design and product design engineering. This paper reports 24 cognitive processes investigated in a subset of 33 studies aligning with two viewpoints on the nature of designing: (V1) design as search (10 processes, 41.7%); and (V2) design as exploration (14 processes, 58.3%). Studies on search focused on solution search and problem structuring, involving: long-term memory retrieval; working memory; operators and reasoning processes. Studies on exploration investigated: co-evolutionary design; visual reasoning; cognitive actions; and unexpected discovery and situated requirements invention. Overall, considerable conceptual and terminological differences were observed among the studies. Nonetheless, a common focus on memory, semantic, associative, visual perceptual and mental imagery processes was observed to an extent. We suggest three challenges for future research to advance the field: (i) developing general models/theories; (ii) testing protocol study findings using objective methods conducive to larger samples and (iii) developing a shared ontology of cognitive processes in design

    Mathematics teachers’ professional knowledge

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    This paper addresses the study of teachers’ knowledge, beliefs, conceptions and practices, presenting some illustrations from the area of problem solving. In mathematics education, the teacher has attracted much less work than the student. This may be due, in part, to the different knowledge base of interest in each case. Regarding students, we are concerned with their learning of mathematics. The nature of mathematical knowledge is itself problematic, yet that does not seem to raise too many difficulties for our work. Regarding teachers, it is much less clear what is the specific knowledge (nec-essary for teaching mathematics) that we should be looking at. Is it knowledge of math-ematics content? Of mathematics pedagogy? Of students’ cognitive processes? Some mixture of several of these? In the first part of the paper I will briefly review work done on teachers’ professional knowledge and related concepts within and outside PME. Then, I will present cases taken from empirical research and discuss a few concepts used in our investigations. And in the final part I will contrast some general frameworks to study mathematics teachers’ professional knowledge and draw some perspectives for future work
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