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关键词： Encoding   Costs   Discrete cosine transforms   Transforms   Quantization (signal)   Telecommunications   Computer science   SHVC   probability   Index Terms   AII-zero block   partial-zero block  

摘要： To seamlessly adapt to time-varying network bandwidths, the Quality Scalable High-Efficiency Video Coding (QSHVC) is developed. However, its coding process is overly complex, and this seriously limits its wide applications in real-time environments. Therefore, it is of great significance to study fast coding algorithms for QSHVC. In this paper, we propose a novel probability-based zero-block early termination algorithm for QSHVC. First, we observed that the generated residual coefficients follow the Laplace distribution if a CU is accurately predicted. According to this observation, we derive the sum of squared differences based All-Zero Block (AZB) decision condition. Second, we develop the Hadamard Transform (HT)-based zero-valued quantized coefficient decision condition to obtain zero-valued quantized coefficients and the corresponding Partial-Zero Block (PZB). Third, the probability of each coding mode and coding depth being chosen as the best ones are combined with both AZBs and PZBs to derive the probability-based early termination condition. The experimental results show that the proposed algorithm can improve the average coding speed by 79.85% with a 0.34% decrease in BDBR.

关键词： Teacher attitudes   teacher beliefs   professional documents  

摘要： Instrument development is an important step towards unlocking the analytical power of teacher attitudes and beliefs towards Computer Science (CS). Teacher dispositions have strong empirical and theoretical ties to teacher motivation, professional choices, and classroom practices. To determine consensus desirable attitudes and beliefs, we analyzed 17 key documents produced by 12 national and international organizations associated with CS and the CS education reformmovement. An analysis of 98 relevant coded segments yielded four dispositional targets: an equity orientation, a teacher growth mindset, and key beliefs regarding (career) outcomes and epistemology of CS. Statements crafted for these targets as well as self-efficacy were reviewed through an expert panel (N = 5) and a pilot study (N = 22) before the T-ABC was administered to elementary teachers in a large grant-funded outreach project (N = 772). Psychometric analysis demonstrates high reliability (Cronbach's alpha = 0.89) and satisfactory extraction and loading onto a three factor model, with CS beliefs, growth mindset, and self-efficacy as major factors. Identification and measurements of teacher dispositions enables further analysis of how teacher beliefs may support or hinder effective practice in CS instruction, how teacher populations may differ, and how identified dispositions may change with exposure to various CS learning experiences.

关键词： Computer science education   high schools   structuration theory   case study  

摘要： In the age of computing, there still exist many schools that do not offer computer science courses. The reason can be esoteric to designers of interventions, curricula, and policies. This study aims to answer the research question: What do school officials perceive as barriers to and supports for offering computer science courses at their school? This article provides a case study of four public high schools in the state of Georgia to better understand the barriers to adopting computer science. Interviews conducted with school principals, counselors, and teachers were thematically analyzed to study each case. The pattern that emerged from these themes is framed by structuration theory, wherein the structures (school policies, resources, and courses) influence the agents (teachers, students, the community), and in turn, the agents influence the structures. This framing provides insights into what attributes can be supports for or barriers against schools offering computer science courses.

关键词： Computer science education   secondary school   teacher professional development   formal learning environments   curriculum development   research practice partnership  

摘要： Context Introducing Computer Science (CS) into formal education can be challenging, notably when considering the numerous stakeholders involvedwhich include the students, teachers, schools, and policy makers. We believe these perspectives should be considered conjointly, which is possible within Research Practice Partnerships (RPPs). RPPs look to bridge research-practice gaps and have seen an increase in the field of education and CS-education. Unfortunately, RPPs are considered to be under-researched, in addition to presenting their own challenges. Objectives To the purpose of assessing how RPPs may support the successful introduction of CS into formal education, we investigate three perspectives (students, teachers, and RPP stakeholders) and their interplay within the context of a multi-institution RPP conducting a pilot program to introduce CS to secondary school students. Methods A mixed methods analysis was employed to triangulate data in a concurrent triangulation design. The data included (i) three surveys distributed over the semester to 106 grade 9 students (ages 12-14), (ii) four teacher-journals, (iii) two interviews and four focus groups with the teachers and representatives of the partner institutions. Findings From the students' perspective, while their self-efficacy increased, their motivation decreased throughout the semester due to a miss-match between their expectations and the course. The findings also indicate that gender biases and heterogeneity are already present in grade 9. From the teachers' perspective, co-constructing the study plan, having access to regular support and collaborating within a community of practice when starting to teach CS all facilitated the teachers' experience. Finally, from the RPP's perspective the collaboration between stakeholders and having researchers evaluate the program were considered to be key elements in the pilot program. However, there appears to be a research-practice gap, in large part due to limited inte

关键词： Graphics processing units   Memory management   Data transfer   Parallel processing   Lead   Computer science   Sparse matrices   Data reuse   GPU memory oversubscription   graph computing   partition-based method   zero-copy  

摘要： Graph analytics are widely used including recommender systems, scientific computing, and data mining. Meanwhile, GPU has become the major accelerator for such applications. However, the graph size increases rapidly and often exceeds the GPU memory, incurring severe performance degradation due to frequent data transfers between the main memory and GPUs. To relieve this problem, we focus on the utilization of data in GPUs by taking advantage of the data reuse across iterations. In our studies, we deeply analyze the memory access patterns of graph applications at different granularities. We have found that the memory footprint is accessed with a roughly sequential scan without a hotspot, which infers an extremely long reuse distance. Based on our observation, we propose a novel framework, called Liberator, to exploit the data reuse within GPU memory. In Liberator, GPU memory is reserved for the data potentially accessed across iterations to avoid excessive data transfer between the main memory and GPUs. For the data not existing in GPU memory, a Merged and Aligned memory access manner is employed to improve the transmission efficiency. We also further optimize the framework by parallel processing of data in GPU memory and data in the main memory. We have implemented a prototype of the Liberator framework and conducted a series of experiments on performance evaluation. The experimental results show that Liberator can significantly reduce the data transfer overhead, which achieves an average of 2.7x speedup over a state-of-the-art approach.

关键词： Continuing professional development   CPD   teacher professional development   computer science   computing education  

摘要： As technology and curricula continue to evolve and develop, the prevalence and effectiveness of continuing professional development (CPD) opportunities for computer science teachers is becoming increasingly more important. However, key questions remain about what the characteristics are for effective CPD in this context. Through the presentation of existing literature and the qualitative analysis of interviews with 32 employees from 13 English colleges (n = 14 computer science lecturers, 10 course leaders, and 8 members of senior leadership), this article answers the following question: What are the characteristics of effective continuing professional development for computer science teachers in the 16-18 sector? Existing literature indicates how CPD benefits from (1) knowledge development and application to classroom teaching;(2) self-efficacy development and measurement;(3) observation, feedback, and reflection;(4) collaboration and communities of practice;(5) sufficient time;and (6) institution support. Meanwhile, the thematic analysis of interview data led to the creation of five overarching themes: (1) computer science CPD should address various knowledge domains, (2) CPD requires institutional support, (3) CPD should be engaging, (4) computer science CPD should involve a combination of activities, and (5) CPD should be measurable. This qualitative article also presents interview excerpts and contributes to computing education research and practice by presenting a set of 30 guidelines that outlines the characteristics of effective CPD in the context of computer science teachers in the 16-18 sector. These guidelines could be beneficial for both CPD providers and educators in ensuring CPD opportunities are designed more effectively and with an understanding of both parties' needs.

关键词： Black engineering students   STEM   Transfer student adjustment  

摘要： Black engineering transfer students face unique challenges while navigating the transfer process from a community college to a 4-year institution. The purpose of this paper is to better understand the experiences of these students and the ways in which they adjust to the 4-year school. We identify specific challenges noted by Black engineering transfer students in their experiences related to: (1) heuristics of teaching and learning that they had to adapt to in order to successfully navigate new campus environments;(2) information gaps that students encountered in what faculty seemed to expect them to already know;and (3) problems in having to adjust to the differences in the academic demands of the 4-year engineering program. In addition to unpacking our findings along these specific domains, we attend to the potential impact of having these challenges in a large, urban, metropolitan area. © 2022, The Author(s), under exclusive licence to Springer Nature B.V.

关键词： Handwriting recognition   Features extraction   Transfer-learning   CNN   Concatenation technique  

摘要： Handwriting recognition is a multi-step process that includes data collection, preprocessing, feature extraction, and classification in order to create a final prediction. This process becomes more and more delicate when dealing with the scriptures of college or secondary school learners. The primary purpose of this research is to offer an improved model for classifying images of computer science words vocabulary written by learners. Indeed, the aim is to develop a reliable handwriting recognition system for the benefit of the educational field. The proposed recognition model based on the combination of four pre-trained CNNs models, namely ResNet50 V2, MobileNet V2, ResNet101 V2, and Xception. Our earlier established Computer Science Vocabulary Dataset (CSVD) is used to build and validate the proposed concatenated model. Then, we have applied preprocessing operations to reduce irregularities, like fuzzy letters and distorted undefined symbols. The proposed CNN model is trained on the concatenated features generated by the four pre-trained CNNs using a parallel deep feature extraction approach. To evaluate the performance of our recognition system, we have used different common evaluation measures. The average accuracy of the proposed system for handwritten words vocabulary is 99.97%, and the overall loss rate is 3.56%. In addition, these performances have been compared with alternative state-of-the-art models and better performance has been observed.

关键词： Active learning   computer science engineering (CSE)   higher education   model of empathy   perspective taking (PT)   professional skills   transversal competence  

摘要： Contribution: This article proposes and applies a new systemic 3-D model and a methodology for empathy awareness and development, integrating different partial approaches found in the literature for developing empathy as a transversal ***: Empathy is a competence linked to collaboration and teamwork. Perspective taking (PT) is an important component of empathy and it is key for professionals today. Even though empathy is valued in computer science engineering (CSE) courses, it is not yet fully addressed as an integral part of the training *** Outcomes: Both the model and the methodology are put into practice with a group of first-year CSE students, highlighting the possibilities of the proposal for this course of studies. The experience presented here is an example of a classroom activity in which awareness and PT are addressed, as key components, in relation to the collaborative work toward achieving *** Design: The methodological proposal is applied to guide educators' decisions so that they can work on empathy in the classroom. Responses to several standardized and ad-hoc questionnaires by students from two universities are ***: The results revealed low to medium empathy levels in participating students, but a higher perception of their own empathic ability. The proposed methodology allows students to become aware of and develop some initial changes in relation to empathy, particularly in its PT component, through classroom work.

关键词： Imaging and sensing   Imaging techniques   Computer science   Optical sensors  

摘要： Image sensors capable of capturing individual photons have made tremendous progress in recent years. However, this technology faces a major limitation. Because they capture scene information at the individual photon level, the raw data is sparse and noisy. Here we propose CASPI: Collaborative Photon Processing for Active Single-Photon Imaging, a technology-agnostic, application-agnostic, and training-free photon processing pipeline for emerging high-resolution single-photon cameras. By collaboratively exploiting both local and non-local correlations in the spatio-temporal photon data cubes, CASPI estimates scene properties reliably even under very challenging lighting conditions. We demonstrate the versatility of CASPI with two applications: LiDAR imaging over a wide range of photon flux levels, from a sub-photon to high ambient regimes, and live-cell autofluorescence FLIM in low photon count regimes. We envision CASPI as a basic building block of general-purpose photon processing units that will be implemented on-chip in future single-photon cameras. The sparse, noisy, and distorted raw photon data captured by single-photon cameras make it difficult to estimate scene properties under challenging illumination conditions. Here, the authors present Collaborative photon processing for Active Single-Photon Imaging (CASPI), a technology-agnostic, application-agnostic, and training-free photon processing pipeline for high-resolution single-photon cameras.