cRedit-based and reputation retrieval system

The Journal of Supercomputing - The challenge of a mobile ad-hoc network (MANET) or hybrid wireless network (HWN) is that every node must rely on others to forward its messages, but selfish nodes...     

MEMIS: A Mobile-Supported English-Medium Instruction System

Education is one of the most important elements in our lives, as it provides a direct gain in knowledge. Thus, in order to provide better academic achievement, more and more instructors are adapting collaborative learning to their classes. However, two major problems lurk behind collaborative learning. First, it is difficult to apply collaborative learning because students tend to engage passively with traditional lectures. As a result, interactive technologies such as clickers have been applied to increase interactive learning and raise the rate of interaction. Nevertheless, these interactive technologies still have some limitations, such as limited mobility, high costs, setup issues, technical difficulties, and little support of higher-order thinking skills. Second, recently there has been an increasing number of EMI (English as Medium of Instruction) courses added to university course offerings in countries where English is not the first language. The goal of these courses is to support university internationalization and address the global status of English. However, it is even harder to achieve in-class interaction in large EMI lecture courses. In addition, some studies argue that EMI courses might affect the overall learning of course content because of students’ poor lecture comprehension and passive engagement in class.In order to address the limitations of interactive technologies, encourage more collaborative learning, facilitate greater in-class interaction in large lecture courses, and resolve students’ poor lecture comprehension in EMI courses, the author introduces MEMIS (Mobile-Supported English-Medium Instruction System), which includes both a T&S (Teachers & Students) mobile app and an EMI pedagogical method. The author first provides detailed implementation and all the features of the T&S mobile app, which improves students’ perceptions of classroom participation and in-class interaction. Then the author explains how she develops her EMI pedagogy such that it utilizes the features of the T&S mobile app to: 1) increase students’ overall learning in her EMI course, 2) develop students’ construction of knowledge and higher-order thinking, and 3) achieve all six cognitive processes from Bloom’s revised taxonomy. The author adapts a quasi-experimental design, statistically analyzes the effectiveness of both exam scores and final grades between a control group and an experimental group, and then asks students to evaluate their experiences and provide feedback about MEMIS. Based on both statistical results and students’ overall feedback, the author confirms that MEMIS is an effective approach that improves lecture comprehension, encourages more class engagement, promotes collaborative learning, and achieves better learning outcomes.     

Protecting against malicious and selective forwarding attacks for P2P search & retrieval system

With recent advances in networking technology, emerging networks continue to play an increasing role in the lives of most users. The Internet search and retrieval system is so powerful that it helps us to share information and perspectives from across the world. However, the threat of censorship exists on some centralized search engines, since all of their information is currently controlled by these sites administrators. The restriction and control of information are pervasive enough within governments and organizations to censor or intrude on even the most free and uncontrolled communication media. For this reason, the Peer-to-Peer (P2P) search and retrieval system is designed to resist censorship over the network. Nevertheless, its decentralized nature makes it very difficult to infer information that cannot be measured directly, such as the proportion of subverted and selfish nodes. Moreover, the situation is even more challenging when the network becomes extremely large. Hence, I propose a dynamic adaptive algorithm that can: 1) tackle the censorship and security issues; 2) determine the proportion of subverted and selfish nodes; 3) defend against malicious and selective forwarding attacks by appropriately adjusting the number of requests to ensure high match probability; 4) guarantee robustness and scalability even with different random networks and varied network sizes. In several experiments, I demonstrate that my algorithm can effectively and accurately estimate these metrics and manage the system, even when the network has a large proportion of malicious nodes, a large proportion of selfish nodes, or a mere partial view of network membership.     

Optimization of polymer light emitting devices using TiOx electron transport layers and prism sheets

The internal and external efficiency of polymer light emitting devices were found can be simultaneously improved by insertion a high refractive index material, titanium oxide (TiO_x), to the emission layer and a prism sheet attached to the substrate. The TiO_x layer increased the internal efficiency due to a better electron injection and hole confinement. However, it led a wider angular emission profile with more photons trapped in the substrate. By using the prism sheet, those trapped light was efficiently coupled to the air. The extraction efficiency enhancement was increased from 33.1% to 54.4% and the overall current efficiency was improved up to 86%.     

Maintaining censorship resistance in the iTrust network for publication,search and retrieval

This paper presents the architecture of the iTrust system together with algorithms for maintaining censorship resistance. In iTrust, metadata describing documents, and requests containing keywords, are distributed to randomly chosen nodes in the iTrust network. If a node receives a request containing keywords that match metadata it holds, it sends the URL of the matching document to the requesting node, which then retrieves the document from the source node. A novel detection algorithm estimates the proportion of operational nodes in the iTrust network, by comparing the empirical probabilities of the number of responses received for a node’s request with the analytical probabilities for a match, for various proportions of operational nodes. A novel defensive adaptation algorithm increases the number of nodes to which the requests are distributed, in order to maintain the same high probability of a match when some of the nodes are non-operational or malicious as when all of the nodes are operational. Extensive experimental evaluations demonstrate the effectiveness of the architecture and the algorithms for maintaining censorship resistance in the iTrust network.     

MOS photodetectors based on Au-nanorod doped graphene electrodes

By using Au-nanorod (Au-NR) doped graphene as a transparent conducting electrode, Si-based metal-oxide-semiconductor (MOS) photodetectors (PDs) exhibit high external quantum efficiency (EQE) and fast response time. It is found that upon adding Au-NRs to the graphene, a significant increase in EQE is observed for both planar and Si-nanotip (Si-NT) MOS PDs. The planar Si-based MOS PDs reveal a notable photoresponse with an EQE of 49% at the peak wavelength of 530 nm under zero bias and an EQE of 66% at the peak wavelength of 600 nm under - 0.4 V bias. For the Si-NTs MOS PD, it exhibits a relatively high EQE of 71% under - 4 V bias due to the effect of light trapping arising from the nature of the Si-NT array.     

Mobile Decentralized Search and Retrieval Using SMS and HTTP

Events over the past year have demonstrated the utility of mobile devices for coordinating mass gatherings and organizing protests in support of social change. However, governments have countered by censoring or disabling centralized search services and social networking sites. This paper describes a decentralized search and retrieval system, named iTrust, that provides resistance against the vulnerabilities of centralized services. It describes the iTrust with SMS interface and the iTrust SMS-HTTP bridge, which enable any SMS-capable mobile phone to communicate with and obtain information from HTTP nodes in the iTrust network. It also describes the iTrust over SMS protocol, which enables mobile phones to communicate directly with each other and share information in a peer-to-peer fashion bypassing the Internet. The paper also describes the Android user interface, which builds on the basic SMS capabilities of mobile phones and offers a user-friendly way of accessing the iTrust with SMS or iTrust over SMS implementation. Finally, the paper presents a performance evaluation of the iTrust search and retrieval system.     

TCR: a trustworthy and churn-resilient academic distribution and retrieval system in P2P networks

As the number of people using the internet has surged over the past few years, more and more people are choosing to share and retrieve information online. There are several decentralized retrieval applications that provide file-sharing platforms for exactly this purpose. However, these applications cannot guarantee churn resilience, trustworthiness, or low cost of retrieval. Therefore, in this paper, we present a system called trustworthy and churn-resilient academic distribution and retrieval system in P2P networks, or TCR, which: (1) ensures that information will not be centralized by central network administrators; (2) utilizes LSH to classify nodes with similar research topics into a local subnetwork, and applies routing algorithms with trust score equations to determine the next trustworthy node to forward the message, thus ensuring each node can accurately and efficiently find its trustworthy nodes within only a few hops; (3) provides a trustworthy management system that itself deals in trustworthiness, ensuring that even when there is a large proportion of malicious nodes, the system can still detect and punish misbehaving nodes; (4) guarantees that nodes can still retrieve the desired files even when in high-churn networks. We finally demonstrate that our TCR entails low message costs, provides high match rates, detects malicious nodes, and ensures churn resilience and search efficiency when compared to other P2P retrieval systems.

     

The study of tactile feeling and It's expressing vocabulary

Tactile feeling is an important sense of people's use of products in our daily life. However, how people express and verbalize their tactile feeling has hardly been systematically studied. Thus, the purpose of this study is to investigate how people describe their tactile feeling and how this expression will be affected by visual experience. To achieve the purpose a focus interview was conducted for this study. A set of 51 samples of various textures based on a literature review and a pilot study was prepared as reference stimuli in the interview to evoke respondents' tactile feeling and experience. Six blind and 5 blindfolded respondents were recruited for the interview. In each interview session the respondent was guided and encouraged by the interviewer to exhaustively describe his/her tactile feeling on freely touching the reference samples only, without the aid of vision. The Kawakita Jiro method (KJ method) then was used to sort, classify and analyze the collected vocabularies of tactile feeling. The results showed that the expressed vocabularies of tactile feeling can be classified into five dimensions: “objective/measurable”, “evaluative/aesthetic”, “social status and positions”, “emotional” and “interface quality”. Among them, vocabularies of “objective/measurable” and “interface quality” were the most frequently mentioned by respondents, while those of the “evaluative/aesthetic” were the least. The expressed vocabularies between the blind and the blindfolded respondents were also found to be significantly different in the five dimensions.     

Giant white and blue light emission from Al(2)O(3) and ZnO nanocomposites

A new and general approach enabling us to amplify not only the bandgap emission of ZnO nanorods but also the defect emission of Al(2)O(3) is proposed. The light intensity of the band edge emission of ZnO nanorods can be improved by as much as 19 times after the decoration of Al(2)O(3) layers. Moreover, white light emission arising from Al(2)O(3) defects in ZnO/Al(2)O(3) nanostructures also shows a large enhancement factor of 12 times. Our new strategy offers an alternative possibility to create strong white and blue light-emitting devices.