Non-thermal radiation of black hole off canonical typicality

We study the Hawking radiation of black holes by considering the canonical typicality. For the universe consisting of black holes and their outer part, we directly obtain a non-thermal radiation spectrum of an arbitrary black hole from its entropy, which only depends on a few external qualities (known as hairs), such as mass, charge, and angular momentum. Our result shows that the spectrum of the non-thermal radiation is independent of the detailed quantum tunneling dynamics across black hole horizon. We prove that the black hole information paradox is naturally resolved by taking account the correlation between black hole and its radiation in our approach.Comment: 5 pages, 1 figure, pulished on Europhysics Letters, comments are welcome

Mobile App Design for Teaching and Learning: Educators’ Experiences in an Online Graduate Course

This research explored how educators with limited programming experiences learned to design mobile apps through peer support and instructor guidance. Educators were positive about the sense of community in this online course. They also considered App Inventor a great web-based visual programming tool for developing useful and fully functioning mobile apps. They had great sense of empowerment through developing unique apps by using App Inventor. They felt their own design work and creative problem solving were inspired by the customized mobile apps shared by peers. The learning activities, including sharing customized apps, providing peer feedback, composing design proposals, and keeping design journals (blogging), complemented each other to support a positive sense of community and form a strong virtual community of learning mobile app design. This study helped reveal the educational value of mobile app design activities and the web-based visual programming tool, and the possibility of teaching/learning mobile app design online. The findings can also encourage educators to explore and experiment on the potential of incorporating these design learning activities in their respective settings, and to develop mobile apps for their diverse needs in teaching and learning

Online Graduate Students’ Preferences of Discussion Modality: Does Gender Matter?

Audio/video discussion has been used increasingly in online courses due to its affordances in enhancing online communication. However, whether learners of different characteristics can benefit from this discussion modality has not been investigated extensively. This study examined whether gender plays a role in learners’ preferences and perceptions of audio/video discussion as compared to text discussion. The survey data of thirty-six participants’ perceptions were collected and studied after they participated in an audio/video discussion activity. The findings show that females preferred audio/video discussion more than males did, and more females reported that audio/video discussion strengthened their connection with peers. The top three benefits of audio/video discussion perceived by females and males are presented in this paper. Overall, using audio/video discussion to augment online communication and to connect learners is likely to be more effective and perceived more positively by female students than male students. The findings in this study could provide implications for sound pedagogical decisions that satisfy student preferences

Learners’ Interpersonal Beliefs and Generated Feedback in an Online Role-Playing Peer-Feedback Activity: An Exploratory Study

Peer feedback affords interaction and critical thinking opportunities for learners in online courses. However, various factors prevent learners from taking advantage of these promising benefits. This study explored learners’ perceptions of the interpersonal factors in a role-playing peer-feedback activity, and examined the types of peer feedback that learners generated when playing a role. Participants were 16 graduate students engaged in an online role-playing peer-feedback activity. The results from survey responses revealed learners’ positive interpersonal beliefs, including psychological safety and trust, toward the role-playing peer-feedback activity. In addition, more than sixty percent of the participants reported being more comfortable critiquing peers’ work when playing a role. The content analysis of the peer-feedback entries indicated that learners were able to generate highly constructive feedback entries. In addition to adding supportive comments, those feedback entries identified problems, asked questions, and provided suggestions. The results show that role-play strategy has great potential to enhance learners’ interpersonal beliefs in peer-feedback activity and their feedback quality

Design-Grounded Assessment: A Framework and a Case Study of Web 2.0 Practices in Higher Education

This paper synthesises three theoretical perspectives, including sociocultural theory, distributed cognition, and situated cognition, into a framework to guide the design and assessment of Web 2.0 practices in higher education. In addition, this paper presents a case study of Web 2.0 practices. Thirty-seven online graduate students participated in a small-group collaborative concept mapping activity using Web 2.0 applications (e.g. Webspiration) to construct sophisticated understanding of instructional design processes. The analysis of this case focuses on different assessment strategies adopted to ensure students\u27 successful participation in such technology-rich collaborative context. This case study concludes that a shared goal needs to be in place to establish a purpose of collaboration. The collaborative nature of learning afforded by Web 2.0 applications needs to be acknowledged through the award of grades. That is, both the processes and products of collaborative knowledge construction need to be assessed and formally graded at individual and group levels. This paper also suggests several potential assessment strategies that may enhance smoother Web 2.0 practices, and discusses some possible challenges associated with those strategies

Microblogging for Strengthening a Virtual Learning Community in an Online Course

This paper examines how a microblogging tool (i.e., Twitter) can be effectively used to strengthen a virtual learning community (VLC) in the two sections of a fully online graduate course. Students in this course were consisted of K-12 teachers, school technology specialists, corporate trainers, and military personnel. The microblogging activities were designed to allow quick peer interaction to build the momentum of social learning in the VLC. In this study, we collected quantitative data on sense of community through a Likert scale survey, and rich qualitative data on students\u27 perception about microblogging activities. It was found that students’ sense of community was generally high and students were positive about their microblogging experiences. In addition, microblogging was found to be useful and valuable in sustaining students\u27 learning by doing such as sharing real-world design examples, critiquing design examples with technical knowledge learned in class, and quick and short commenting with peer support in a VLC. Based on the findings, the authors aim to provide design suggestions for educators and instructional designers to incorporate this social web tool in strengthening virtual learning communities in a meaningful and engaging way

Peer Feedback to Facilitate Project-Based Learning in an Online Environment

There has been limited research examining the pedagogical benefits of peer feedback for facilitating project-based learning in an online environment. Using a mixed method approach, this paper examines graduate students’ participation and perceptions of peer feedback activity that supports project-based learning in an online instructional design course. Our findings indicate that peer feedback can be implemented in an online learning environment to effectively support project-based learning. Students actively participated in the peer feedback activity and responded positively about how the peer feedback activity facilitated their project-based learning experiences. The results of content analysis exploring the peer feedback reveal that learners were mostly supportive of peers’ work and they frequently asked questions to help advance their peers’ thinking. The implications and challenges of implementing peer feedback activity in an online learning environment are discussed

A multi-task learning CNN for image steganalysis

Convolutional neural network (CNN) based image steganalysis are increasingly popular because of their superiority in accuracy. The most straightforward way to employ CNN for image steganalysis is to learn a CNN-based classifier to distinguish whether secret messages have been embedded into an image. However, it is difficult to learn such a classifier because of the weak stego signals and the limited useful information. To address this issue, in this paper, a multi-task learning CNN is proposed. In addition to the typical use of CNN, learning a CNN-based classifier for the whole image, our multi-task CNN is learned with an auxiliary task of the pixel binary classification, estimating whether each pixel in an image has been modified due to steganography. To the best of our knowledge, we are the first to employ CNN to perform the pixel-level classification of such type. Experimental results have justified the effectiveness and efficiency of the proposed multi-task learning CNN