Design and implementation of a smart dual axis sun tracker based on astronomical equations

This paper presents a new design algorithm for stand-alone solar tracking system based on ATMEL Microcontroller. The proposed idea of the design is based on astronomical equations to determine the position of the sun in the sky at any time of the day to calculate the tilt angle and polar angle for the two axis tracking purposes. The system is capable of tracking the sun properly at any position on the earth because of the general nature of the algorithm used in the design. At the same time the system reliability, cost effectiveness, precision and flexibility are taken into consideration

Desıgn of a control and data acquısıtıon system for a multı-mode solar trackıng farm

This paper presents a combination network design for a solar tracking farm consisting of n-solar tracking systems. Serial communication protocol has been adopted for this network with developed strategy to make the farm expandable for possible future extension. The master control unit is responsible for managing all the trackers of the sun location in multi-tracking mode, diagnosis all the trackers for any faults and give complete information about the produced power by each of the solar tracking system. This network protocols is designed to deal with the error control, congestion control and flow control for data transmission in the network

EFL teachers’ practices while teaching reading comprehension in Jordan: Teacher development implications

This study investigated in-service English as foreign language (EFL) teachers’ practices while teaching reading comprehension at schools. Thirty EFL teachers were observed to identify their current practices and teaching quality. To triangulate the trustworthiness of the data, out of those thirty, ten EFL teachers were interviewed. The observation data were analyzed using descriptive statistic particularly frequencies and percent, and the interview data were analyzed using thematic content analysis. The findings of the study revealed that teachers taught students reading comprehension traditionally. Most of the observed and interviewed teachers knew the names of the reading comprehension strategies and the stages of teaching reading comprehension. However, they did not know how to employ and practice them. Based on the results, it is necessary to design professional development programs to empower EFL teachers on how to present these strategies and to conduct further research on this topic while considering other variables, like experience and the nature of curricula

Effects of employing in-service EFL teachers strategy-based instruction on their performance of teaching listening comprehension in Amman-Jordan

This study investigated the effect of a proposed training program based on strategy-based instruction (SBI) on EFL female teachers' performance in teaching listening comprehension. The participants of the study were 36 EFL female teachers who were purposefully chosen by EFL supervisors from schools in Amman. The participants were randomly divided into two groups: 18 EFL teachers in the experimental group who were trained according to the proposed training program and 18 teachers in the control group who were received a conventional training program. A teaching listening comprehension scale and an observation checklist were used as research tools. Analysis of covariance (ANCOVA) was employed to identify any statistically significant differences between the two groups on teachers' performance in teaching listening comprehension. The findings revealed that the teaching performance in listening comprehension of female EFL teachers in the experimental group outperformed the control group, and employed most of the SBI when the participants were observed. Based on the results of the study, the researcher recommends that future research be investigated on the effect of research-based strategies on teacher effectiveness in teaching other language skills

Gallium-67 Scintigraphy in the Era of Positron Emission Tomography and Computed Tomography : Tertiary centre experience

Objectives: Although 18F-fluorodeoxyglucose positron emission tomography (PET)/computed tomography (CT) has largely replaced the use of gallium-67 (67Ga) scintigraphy in the evaluation and follow-up of lymphoma patients, 67Ga scans are still of value, particularly in countries where no PET/CT service is available. The current study presents the experience of a tertiary care centre using 67Ga scintigraphy for the evaluation of lymphomas and infections. Methods: A retrospective review was conducted of all 67Ga scans performed between 2007 and 2011 at the Royal Hospital in Muscat, Oman. Images and reports of 67Ga scans were compared to clinical and radiological follow-up data including CT and PET/CT scans and biopsies when available. Results: A total of 74 patients were referred for 67Ga scintigraphy during this period with 12 patients excluded due to lack of follow-up data, resulting in 62 patients. Among these patients, 90 67Ga scans were performed, including 59 for lymphoma, 29 for infection and two for sarcoidosis assessment. Of the infection assessment scans, 22 were performed to assess pyrexia of unknown origin and seven for follow-up after known infections. Sensitivity and specificity were found to be 80% and 88%, respectively, for the lymphoma assessment scans. For the infection assessment scans, sensitivity and specificity were reported to be 80% and 100%, respectively. Conclusion: Results from this study were consistent with other reported rates of 67Ga scan sensitivity and specificity in the evaluation of lymphomas and infections. This indicates that 67Ga scintigraphy is a useful tool for these types of evaluations when PET/CT services are not available

Combined Positron Emission Tomography and Computed Tomography : Option or necessity?

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Energy Efficient Network Function Virtualisation in 5G Networks

Once the dust settled around 4G, 5G mobile networks become the buzz word in the world of communication systems. The recent surge of bandwidth-greedy applications and the proliferation of smart phones and other wireless connected devices has led to an enormous increase in mobile traffic. Therefore, 5G networks have to deal with a huge number of connected devices of different types and applications, including devices running life-critical applications, and facilitate access to mobile resources easily. Therefore given the increase in traffic and number of connected devices, intelligent and energy efficient architectures are needed to adequately and sustainably meet these requirements. In this thesis network function virtualisation is investigated as a promising paradigm that can contribute to energy consumption reduction in 5G networks. The work carried out in this thesis considers the energy efficiency mainly in terms of processing power consumption and network power consumption. Furthermore, it considers the energy consumption reduction that can be achieved by optimising the locations of virtual machines running the mobile 5G network functions. It also evaluates the consolidation and pooling of the mobile resources. A framework was introduced to virtualise the mobile core network functions and baseband processing functions. Mixed integer linear programming optimisation models and heuristics were developed minimise the total power consumption. The impact of virtualisation in the 5G front haul and back haul passive optical network was investigated by developing MILP models to optimise the location of virtual machines. A further consideration is caching the contents close to the user and its impact on the total power consumption. The impact of a number of factor on the power consumption were investigated such as the total number of active users, the backhaul to the fronthaul traffic ratio, reduction/expansion in the traffic due to baseband processing, and the communication between virtual machines. Finally, the integration of network function virtualisation and content caching were introduced and their impact on improving the energy efficiency was investigated

Resilient Back Propagation Algorithm for Breast Biopsy Classification Based on Artificial Neural Networks

Non

Primary User Emulation Attacks: A Detection Technique Based on Kalman Filter

Cognitive radio technology addresses the problem of spectrum scarcity by allowing secondary users to use the vacant spectrum bands without causing interference to the primary users. However, several attacks could disturb the normal functioning of the cognitive radio network. Primary user emulation attacks are one of the most severe attacks in which a malicious user emulates the primary user signal characteristics to either prevent other legitimate secondary users from accessing the idle channels or causing harmful interference to the primary users. There are several proposed approaches to detect the primary user emulation attackers. However, most of these techniques assume that the primary user location is fixed, which does not make them valid when the primary user is mobile. In this paper, we propose a new approach based on the Kalman filter framework for detecting the primary user emulation attacks with a non-stationary primary user. Several experiments have been conducted and the advantages of the proposed approach are demonstrated through the simulation results.Comment: 14 pages, 9 figure