1,721,004 research outputs found
Spectrum sensing optimisation for dynamic primary user signal
No full textWe propose a multi-layer spectrum sensing optimisation algorithm to maximise sensing efficiency by computing the optimal sensing and transmission durations for a fast changing, dynamic primary user. Dynamic primary user traffic is modelled as a random process, where the primary user changes states during both the sensing period and transmission period to reflect a more realistic scenario. Furthermore, we formulate joint constraints to correctly reflect interference to the primary user and lost opportunity of the secondary user during the transmission period. Finally, we implement a novel duty cycle based detector that is optimised with respect to PU traffic to accurately detect primary user activity during the sensing period. Simulation results show that unlike currently used detection models, the proposed algorithm can jointly optimise the sensing and transmission durations to simultaneously satisfy the optimisation constraints for the considered primary user traffic
Orientation analysis for antenna diversity using circular polarization
No full textTraditional polarization diversity systems have relied on the distribution of obstacles within the mobile medium to achieve signal decorrelation and power coupling between orthogonal polarizations. If the channel does not facilitate adequate power coupling, signal diversity is suboptimal because signal contribution from the polarization with lesser power is limited. Further, due to the presence of a dominant polarization, the signal power received in the orthogonal polarizations becomes a function of the transmitter orientation. The use of circular polarization at the transmitter is proposed to facilitate power coupling and alleviate the branch power imbalance between the vertical and horizontal polarizations. The analysis shows that if circular polarization is used, the branch power imbalance between the vertical and horizontal polarizations can be significantly lower than linear polarization, and that the cross polarization discrimination becomes independent of the transmitter orientation. The proposed antenna configuration to achieve circular polarization allows for polarization diversity to be implemented in the uplink and downlink
Holistically approaching curriculum renewal: A case study of the Queensland University of Technology
No full textThere are still many programs in Australia and overseas where curricula comprise largely 20th Century-relevant graduate outcomes, framed in 20th Century learning and teaching approaches. A ‘Dynamic and Deliberative Model for Curriculum Renewal’ (DDMCR) model exists for undertaking such curriculum renewal that draws on the experiences of educators around the world, however there are few experiences to date in applying this model. At the Queensland University of Technology, the 2012 accreditation by Engineers Australia observed that, despite being exposed to relevant discipline-specific engineering curriculum and practice, students did not seem to be aware of the relevance of sustainable development to their degree, beyond first year exposure. In addressing this feedback, level 8 Australian Qualifications Framework, and drawing ideas from the DDMCR model, faculty senior management undertook a full review of the engineering curriculum
Detection of dynamic primary user with cooperative spectrum sensing
No full textIn this paper we demonstrate that existing cooperative spectrum sensing formulated for static primary users cannot accurately detect dynamic primary users regardless of the information fusion method. Performance error occurs as the sensing parameters calculated by the conventional detector result in sensing performance that violates the sensing requirements. Furthermore, the error is accumulated and compounded by the number of cooperating nodes. To address this limitation, we design and implement the duty cycle detection model for the context of cooperative spectrum sensing to accurately calculate the sensing parameters that satisfy the sensing requirements. We show that longer sensing duration is required to compensate for dynamic primary user traffic
Velocity Estimation in Cellular Systems Based on the Time-Frequency Characteristics of the Received Signal
No full textStrategies to engage engineering students in group project work
No full textProject focused group work is significant in developing social and personal skills as well as extending the ability to identify, formulate and solve engineering problems. As a result of increasing undergraduate class sizes, along with the requirement for many students to work part-time, group projects, peer and collaborative learning are seen as a fundamental part of engineering education. Group formation, connection to learning objectives and fairness of assessment has been widely reported as major issues that leave students dissatisfied with group project based units. Several strategies were trialled including a study of formation of groups by different methods across two engineering disciplines over the past 2 years. Other strategies involved a more structured approach to assessment practices of civil and electrical engineering disciplines design units. A confidential online teamwork management tool was used to collect and collate student self and peer assessment ratings and used for both formative feedback as well as assessment purposes. Student satisfaction and overall academic results in these subjects have improved since the introduction of these interventions. Both student and staff feedback highlight this approach as enhancing student engagement and satisfaction, improved student understanding of group roles, reducing number of dysfunctional groups whilst requiring less commitment of academic resources
Effect of group formation on performance, task management and social loafing
No full textEngineering graduates of today are required to adapt to a rapidly changing work environment. In particular, they are expected to demonstrate enhanced capabilities in both mono-disciplinary and multi-disciplinary teamwork environments. Engineering education needs, as a result, to further focus on developing group work capabilities amongst engineering graduates. Over the last two years, the authors trialed various group work strategies across two engineering disciplines. In particular, the effect of group formation on students' performance, task management, and social loafing was analyzed. A recently developed online teamwork management tool, Teamworker, was used to collect students' experience of the group work. Analysis showed that students who were allowed to freely allocate to any group were less likely to report loafing from other team members, than students who were pre-allocated to a group. It also showed that performance was more affected by the presence or absence of a leader in pre-allocated rather than free-allocated groups
Detecting Bearing Faults Using Blind Deconvolution and High Frequency Resonance Technique
No full textFrom work placement to employability: A whole-of-course framework
No full textThis paper presents a framework that encompasses work integrated learning but does not focus solely on work experience placement for the development of employability skills. A student and program lifecycle approach has been adopted to assist the journey of the student from novice to emerging professional, and key to this is the development of self-knowledge through critical reflection, that is, an understanding of personal strengths, challenges, needs and strategies for growth in a rapidly changing work environment. The importance of this is confirmed in both national and global contexts where “entry level roles for young people are disappearing” and 70% of all jobs are being radically changed by automation (Foundation for Young Australians, 2015). Engineers are involved at the centre of these changes as well as being impacted by them. And require ever more integrated and flexible resources and systems to connect and assure their learning
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