Shared orchestration within and beyond the classroom

With the introduction of personal computer devices such as smartphones and tablets into school classrooms, teachers have the added task of orchestrating complex dynamic systems of students interacting with networked technologies. One approach to managing the interactions is to add an orchestration system that enables a teacher view and control each student device. An alternative is to share responsibility for orchestration between the teacher, the students, and the technology. In this form of orchestration, the teacher and all the students have similar computer toolkits designed to guide the students through a productive learning activity. An advantage is that the teacher can hand over control to the students to continue the learning activity outside the classroom, assisted by the Activity Guide software.     

Open Collaboration within Corporations Using Software Forges

A software forge is a tool platform for collaborative software development, similar to integrated CASE environments. Unlike CASE tools, however, software forges have been designed for the software development practices of the open source community. The authors discuss their experiences using a software forge to bring open source best practices into corporations. They present the design principles and benefits of a firm-internal software forge and include a case study of how one project at SAP benefitted significantly from being on the forge.     

Embedded blended learning within an Algebra classroom: a multimedia capture experiment

This two‐group, pretest‐posttest, quasi‐experimental study compared secondary students' learning of Algebra II materials over a 4‐week period when identical instruction by the same teacher was delivered through either embedded blended learning (treatment group; n = 32) or a live‐lecture classroom (control group; n = 24). For both groups, instruction was delivered in a normal classroom setting. A math test and a student survey were used to measure students' learning of Algebra II and satisfaction with the instruction. Students in the treatment group showed significantly greater gains in Algebra II test scores and evaluated their learning experiences significantly more positively than did the control group. The great majority (80%) of students in the treatment group preferred the embedded blended learning over traditional live lectures for future learning of math. Students' responses to open‐ended survey questions suggested that students in the treatment group appreciated the: (a) ability to control the pace of instruction; (b) new role of the classroom teacher; (c) lack of distraction in the blended learning environment; and (d) accessibility of the embedded multimedia lessons outside the classroom. This study suggests that screen‐capture instructional technology can be used towards establishing a teacher‐based, embedded blended learning environment within a secondary algebraic classroom.     

Key establishment in large dynamic groups using one-way function trees

We present, implement, and analyze a new scalable centralized algorithm, called OFT, for establishing shared cryptographic keys in large, dynamically changing groups. Our algorithm is based on a novel application of one-way function trees. In comparison with the top-down logical key hierarchy (LKH) method of Wallner et al., our bottom-up algorithm approximately halves the number of bits that need to be broadcast to members in order to rekey after a member is added or evicted. The number of keys stored by group members, the number of keys broadcast to the group when new members are added or evicted, and the computational efforts of group members, are logarithmic in the number of group members. Among the hierarchical methods, OFT is the first to achieve an approximate halving in broadcast length, an idea on which subsequent algorithms have built. Our algorithm provides complete forward and backward security: Newly admitted group members cannot read previous messages, and evicted members cannot read future messages, even with collusion by arbitrarily many evicted members. In addition, and unlike LKH, our algorithm has the option of being member contributory in that members can be allowed to contribute entropy to the group key. Running on a Pentium II, our prototype has handled groups with up to 10 million members. This algorithm offers a new scalable method for establishing group session keys for secure large-group applications such as broadcast encryption, electronic conferences, multicast sessions, and military command and control.     

A simple fingerprinting scheme for large user groups

Digital fingerprinting is an emerging technology to protect multimedia data from piracy, where each distributed copy is labeled with unique identification information. In coded fingerprinting, each codeword of the anti-collusion code is used to represent a user’s fingerprint. In real-world applications, the number of potential users can be very large and hence, the used anticollusion code should be easy to construct and have as many codewords as possible. This paper proposes a simple coded fingerprinting scheme, where the anticollusion code is constructed with an identity matrix. The main advantage of our scheme is its simplicity, as a large number of fingerprints can easily be generated to accommodate a large number of users. To improve collusion resistance, some transformations are performed on the original fingerprint in the embedding phase and the corresponding inverse transformations are performed on the extracted sequence in the detection phase.     

Robotics in the classroom

This article presents an integrated approach for incorporating robotics into secondary education with the objective of further engaging students through an exciting application of math, computers, and science. One of the principal objectives of this university-based outreach effort is to promote the creation of independent programs at the secondary-school level in New Mexico by providing a structured set of resources from which the schools may begin. These resources include an adaptable mobile robot kit with detailed do-it-your-self online instructions, various Web-based course offerings with material directed to both secondary students and teachers, and a personnel support structure, including college engineering faculty, secondary teachers, practicing engineers, undergraduate engineering students, and junior-high and high-school students. An outreach program to integrate robotics into secondary education.     

On the scaling of feedback algorithms for very large multicast groups

Feedback from multicast group members is vital for many multicast protocols. In order to avoid feedback implosion in very large groups feedback algorithms with well-behaved scaling-properties must be chosen. In this paper, we analyse the performance of three typical feedback algorithms described in the literature. Apart from the basic trade-off between feedback latency and response duplicates we especially focus on the algorithms’ sensitivity to the quality of the group size estimation. Based on this analysis we propose a generalised framework for feedback algorithms and especially give recommendations for the choice of well-behaved feedback mechanisms that are suitable for very large groups.     

一种适合大型动态多播的密钥管理方案

分析了已有基于两层结构的密钥管理方案的优缺点,在此基础上综合了上述方案和PE方案的特点,提出了一个新的密钥管理方案,并给出了相应的更新算法。通过对本方案和其他方案的密钥存储量、加密计算量、网络通信量等性能的分析结果表明,该方案在组控制器和子组控制器方面都具有良好的通信效率、较低的计算开销和可扩展性,适用于大型的动态多播环境。     

Databases in the classroom*

Handling information on a variety of media from difference sources has always been an integral part of learning. Children now have the opportunity to use information-handling programs on microcomputers that support the existing curriculum and open up new possibilities for self-directed enquiry learning. This paper summarizes the background to the development of the QUEST ‘family’ of programs and demonstrates the way they are used in History and Geography. Comparisons are also made with other database programs.     

一种适合大群组的完全匿名的短群签名*

基于CS98加密方案和SDH假设,提出一种新的三元组(A,x,y)的零知识证明协议,并基于此协议构造了一种可证明安全的短群签名方案。该方案具有INDCCA2完全匿名性,允许新成员动态加入,并且群管理员不能伪造任何成员的签名,具有不可陷害性。签名长度仅为1 534 bit。     

On finite groups with large degrees of irreducible character

Let G be a finite nontrivial group with an irreducible complex character χ of degree d = χ(1). According to the orthogonality relation, the sum of the squared degrees of irreducible characters of G is the order of G. N. Snyder proved that, if G = d(d + e), then the order of the group G is bounded in terms of e for e > 1. Y. Berkovich demonstrated that, in the case e = 1, the group G is Frobenius with the complement of order d. This paper studies a finite nontrivial group G with an irreducible complex character Θ such that G ≤ 2Θ(1)² and Θ(1) = pq where p and q are different primes. In this case, we have shown that G is a solvable group with an Abelian normal subgroup K of index pq. Using the classification of finite simple groups, we have established that the simple non-Abelian group, the order of which is divisible by the prime p and not greater than 2p ⁴ is isomorphic to one of the following groups: L ₂(q), L ₃(q), U ₃(q), S _z(8), A ₇, M ₁₁, and J ₁.     

An intelligent system for monitoring students' engagement in large classroom teaching through facial expression recognition

Students' disengagement problem has become critical in the modern scenario due to various distractions and lack of student-teacher interactions. This problem is exacerbated with large offline classrooms, where it becomes challenging for teachers to monitor students' engagement and maintain the right-level of interactions. Traditional ways of monitoring students' engagement rely on self-reporting or using physical devices, which have limitations for offline classroom use. Student's academic affective states (e.g., moods and emotions) analysis has potential for creating intelligent classrooms, which can autonomously monitor and analyse students' engagement and behaviours in real-time. In recent literature, a few computer vision based methods have been proposed, but they either work only in the e-learning domain or have limitations in real-time processing and scalability for large offline classes. This paper presents a real-time system for student group engagement monitoring by analysing their facial expressions and recognizing academic affective states: ‘boredom,’ ‘confuse,’ ‘focus,’ ‘frustrated,’ ‘yawning,’ and ‘sleepy,’ which are pertinent in the learning environment. The methodology includes certain pre-processing steps like face detection, a convolutional neural network (CNN) based facial expression recognition model, and post-processing steps like frame-wise group engagement estimation. For training the CNN model, we created a dataset of the aforementioned facial expressions from classroom lecture videos and added related samples from three publicly available datasets, BAUM-1, DAiSEE, and YawDD, to generalize the model predictions. The trained model has achieved train and test accuracy of 78.70% and 76.90%, respectively. The proposed methodology gave promising results when compared with self-reported engagement levels by students.     

BuddyBeads: techno-jewelry for non-verbal communication within teenager girls groups

The extremity in teenagers’ attitudes and actions coupled with the opportunities of mobile communication creates new behaviors and re-shapes existing ones. But, however meaningful the phone is in teenagers’ lives, it is not designed to support their need for emotional communication and group identity. The BuddyBeads project suggests alternative communication forms among teenagers, which emphasize their social structures, behaviors and needs. BuddyBeads are techno-jewelry items that facilitate non-verbal and emotional communication among group members, through codes and signals which the group decided upon together. Each group member has a matching jewelry piece and can use it to communicate her emotional state to the other group members.     

Implementing flipped classroom using digital media: A comparison of two demographically different groups perceptions

Flipped classroom is a relatively new model in education that primarily focuses on learner-centered instructions. In other words, the model allows both management and teachers to build a more active and dynamic learning environment on the campus. The current paper tries to document the implementation of the flipped classroom model in two big data courses. Here, the course contents have been curated from a couple of websites with different contents including videos and short books as well as reports. The mixed-method approach was applied while analyzing the student perceptions in demographically two different groups. It was found that students of both groups responded positively to the flipped classroom, with each focusing on their specific goals. Consequently, the first group focused on the academic achievement whereas the second group with managerial jobs focused on solving problems in their workplaces. Students of both groups, although preferred TED talks and documentaries, they were opposed to university-like videos and O'Reilly short books and reports. Meanwhile, the use of English language contents turned out to be both a challenge and an opportunity for students.     

Content-Centered Collaboration Spaces in the Cloud

Emphasizing communication, collaborative work, and community, the authors envision a cloud-based platform that inverts the traditional application-content relationship by placing content rather than applications at the center, enabling users to rapidly build customized solutions around their content items. The future of collaboration will focus on building and sustaining communities around content, tasks, and ideas. Hosted entities known as content spaces will support ecosystems of users and developers around this content. To make their case, the authors review the dominant trends in computing that motivate the exploration of new approaches for content-centered collaboration and discuss ways to address certain core problems for users and organizations.     

Characterizing communication networks in a web-based classroom: Cognitive styles and linguistic behavior of self-organizing groups in online discussions

In this study, we explore the cognitive style profiles and linguistic patterns of self-organizing groups within a web-based graduate education course to determine how cognitive preferences and individual behaviors influence the patterns of information exchange and the formation of communication hierarchies in an online classroom. Network analysis was performed on communication data collected from 1131 student messages posted in 19 asynchronous online discussion forums to determine centrality, clique membership, and core-periphery structure in the communication networks. The social network data were examined in relation to the students' cognitive style profiles, which were assessed using the Kirton Adaption-Innovation Inventory (KAI) (32 and 33). The cognitive style composition of small cliques (dyadic and triadic) was found to be highly heterogeneous, often with large cognitive gaps between clique members, which suggests that web-based environments may mask cognitive style differences that have been shown to create conflict in face-to-face interactions. In addition, the cognitive style mean of the students in the core of the network was found to be significantly more adaptive than that of the periphery group. To further characterize the nature of the communicative interactions, automated linguistic analysis was used to analyze the students' writing samples. Interestingly, students in the core of the social network demonstrated a significantly higher usage of several language features associated with individuals who actively promote enhanced group performance and cohesion. For our sample, the linguistic behaviors of students in the core of the social network, coupled with their more adaptive cognitive style preferences, suggest that these students may inherently place greater value on fostering group cohesion than those in the periphery.     

Casting shadows in the science classroom

Abstract

Research in mathematics and science education frequently directs one's attention to the limited content knowledge of elementary pre‐service teachers. It is believed, however, that research of this nature leads to a deficit approach to understanding more about the teaching and learning of these subjects. In addition to focusing on the knowers of school mathematics and science, there is a call to acknowledge the problematic nature of knowing (in) mathematics and science. In this paper, the metaphor of shadows is used in a critical exploration of what it means to know and how the cultures of classrooms have shaped these images of knowing. Through the voices of pre‐service teachers, this paper directs one's attention to objects that cast shadows on the learning and knowing of mathematics and science. Three such shadow‐casting objects discussed in this paper are textbooks, teachers, and gendered ideology. The paper seeks to critically illuminate the problematic nature of what it means to know (in) mathematics and science by examining the shadowy texture of unquestioned ideologies.     

基于大型动态多播群组的分层虚拟动态子群密钥管理方案

在互联网高速发展的今天,密钥管理越来越被人们重视,对组通信密钥方面的研究早已开始,而现实中密钥子群的研究成果较少.分层虚拟动态子群密钥管理方案是对大型动态多播群组提出了一种分别基于子组和子组成员两个层次建立一级虚拟动态子组子群和二级虚拟动态成员子群的方法,解决了大型群组子群建立效率低下的问题.