36,559 research outputs found

    FACT -- Operation of the First G-APD Cherenkov Telescope

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    Since more than two years, the First G-APD Cherenkov Telescope (FACT) is operating successfully at the Canary Island of La Palma. Apart from its purpose to serve as a monitoring facility for the brightest TeV blazars, it was built as a major step to establish solid state photon counters as detectors in Cherenkov astronomy. The camera of the First G-APD Cherenkov Telesope comprises 1440 Geiger-mode avalanche photo diodes (G-APD aka. MPPC or SiPM) for photon detection. Since properties as the gain of G-APDs depend on temperature and the applied voltage, a real-time feedback system has been developed and implemented. To correct for the change introduced by temperature, several sensors have been placed close to the photon detectors. Their read out is used to calculate a corresponding voltage offset. In addition to temperature changes, changing current introduces a voltage drop in the supporting resistor network. To correct changes in the voltage drop introduced by varying photon flux from the night-sky background, the current is measured and the voltage drop calculated. To check the stability of the G-APD properties, dark count spectra with high statistics have been taken under different environmental conditions and been evaluated. The maximum data rate delivered by the camera is about 240 MB/s. The recorded data, which can exceed 1 TB in a moonless night, is compressed in real-time with a proprietary loss-less algorithm. The performance is better than gzip by almost a factor of two in compression ratio and speed. In total, two to three CPU cores are needed for data taking. In parallel, a quick-look analysis of the recently recorded data is executed on a second machine. Its result is publicly available within a few minutes after the data were taken. [...]Comment: 19th IEEE Real-Time Conference, Nara, Japan (2014

    Emergency TeleOrthoPaedics m-health system for wireless communication links

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    For the first time, a complete wireless and mobile emergency TeleOrthoPaedics system with field trials and expert opinion is presented. The system enables doctors in a remote area to obtain a second opinion from doctors in the hospital using secured wireless telecommunication networks. Doctors can exchange securely medical images and video as well as other important data, and thus perform remote consultations, fast and accurately using a user friendly interface, via a reliable and secure telemedicine system of low cost. The quality of the transmitted compressed (JPEG2000) images was measured using different metrics and doctors opinions. The results have shown that all metrics were within acceptable limits. The performance of the system was evaluated successfully under different wireless communication links based on real data

    The effectiveness of the creativity trigger module in achieving higher levels of creative thinking among prospective teachers

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    The unoptimised level of creative thinking is seen as an issue among Semester 8 prospective teachers in Malaysian Teacher-Education Institutes (IPG). This could impede their teaching of creative thinking as one of the four components of 21st century skills in schools. In relation to this, this study sets out to investigate prior creativity levels of IPG prospective teachers and develop the Creativity Trigger Module (CTM) as a training module for enhancing their creativity. The Torrance Tests of Creative Thinking (TTCT) was used to compare the prior creativity levels of four respondent groups and test the effectiveness of the CTM on five dimensions of figural creativity, namely fluency, originality, elaboration, resistance to premature closure, abstractness of titles, and their overall creativity. A two-stage cluster sampling technique identified two IPGs with 68 respondents in the state of Johor namely, IPG-Kampus Tun Hussein Onn, Batu Pahat (IPGKTHO) as the control group site (34 respondents), and IPG- Kampus Temenggong Ibrahim, Johor Bahru (IPGKTI) as the treatment group site (34 respondents). Mathematics (MT) and Design and Technology (RBT) are the only two specialist subject combinations that provided enough sample size at both test sites. A quasi-experimental research design was used and this involved intact classes. Data analysis was carried out as follows: ANOVA, ANCOVA, and Wilcoxon Signed Rank Test analysis for TTCT scores while data analysis based on the NVivo software was used for the focus group interviews. Findings on prior creativity levels showed average or low creativity levels among all 4 test groups with IPGKTHO and RBT options having significantly higher posttest marks as compared to IPGKTI and MT option respectively. The CTM was found to improve significantly respondents’ posttest marks for the treatment group in all the five dimensions of figural creativity and, their overall creativity. Feedback from respondents revealed positive support for the CTM. In conclusion, the prior creativity of IPG prospective teachers was at an unoptimised level before treatment but the CTM has been successfully developed as an effective resource for enhancing the creative thinking levels among IPG prospective teachers

    Telescience Testbed Pilot Program

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    The Telescience Testbed Pilot Program is developing initial recommendations for requirements and design approaches for the information systems of the Space Station era. During this quarter, drafting of the final reports of the various participants was initiated. Several drafts are included in this report as the University technical reports

    Efficient classification using parallel and scalable compressed model and Its application on intrusion detection

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    In order to achieve high efficiency of classification in intrusion detection, a compressed model is proposed in this paper which combines horizontal compression with vertical compression. OneR is utilized as horizontal com-pression for attribute reduction, and affinity propagation is employed as vertical compression to select small representative exemplars from large training data. As to be able to computationally compress the larger volume of training data with scalability, MapReduce based parallelization approach is then implemented and evaluated for each step of the model compression process abovementioned, on which common but efficient classification methods can be directly used. Experimental application study on two publicly available datasets of intrusion detection, KDD99 and CMDC2012, demonstrates that the classification using the compressed model proposed can effectively speed up the detection procedure at up to 184 times, most importantly at the cost of a minimal accuracy difference with less than 1% on average

    The Design of a System Architecture for Mobile Multimedia Computers

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    This chapter discusses the system architecture of a portable computer, called Mobile Digital Companion, which provides support for handling multimedia applications energy efficiently. Because battery life is limited and battery weight is an important factor for the size and the weight of the Mobile Digital Companion, energy management plays a crucial role in the architecture. As the Companion must remain usable in a variety of environments, it has to be flexible and adaptable to various operating conditions. The Mobile Digital Companion has an unconventional architecture that saves energy by using system decomposition at different levels of the architecture and exploits locality of reference with dedicated, optimised modules. The approach is based on dedicated functionality and the extensive use of energy reduction techniques at all levels of system design. The system has an architecture with a general-purpose processor accompanied by a set of heterogeneous autonomous programmable modules, each providing an energy efficient implementation of dedicated tasks. A reconfigurable internal communication network switch exploits locality of reference and eliminates wasteful data copies
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