Analysis of symmetry breaking in quartz blocks using superstatistical random matrix theory

We study the symmetry breaking of acoustic resonances measured by Ellegaard et al., Phys. Rev. Lett. 77, 4918 (1996), in quartz blocks. The observed resonance spectra show a gradual transition from a superposition of two uncoupled components, one for each symmetry realization, to a single component well represented by a Gaussian orthogonal ensemble (GOE) of random matrices. We discuss the applicability of superstatistical random-matrix theory to the final stages of the symmetry breaking transition. A comparison is made between different formula of the superstatistics and a pervious work [Abd El-Hady et al, J. Phys. A: Math. Theor. 35, 2361 (2002)], which describes the same data by introducing a third GOE component. Our results suggest that the inverse-chi-square superstatistics could be used for studying the whole symmetry breaking process.Comment: 11 pages, 1 figur

Sequential random selection relaying for energy efficient wireless sensor networks

In a wireless sensor network with relaying capability, intermediate relay nodes are with limited energy budget. To maximize lifetime of relay nodes, selective relay strategies, requiring full channel state information (CSI), are used to utilizes the best relaying channel. Pilot overhead on relay nodes lifetime is reduced by assuming pilot transmission from destination instead of relay nodes. This is only valid if channel reciprocity is assumed. It is evident that channel reciprocity is not valid for low cost simple transceivers, such as sensor node transceivers. In this paper a novel sequential random (SR) selective cooperative relay strategy is proposed in amplify and forward (AF) relay networks for applications with non reciprocal links. The outage probability of SR strategy is derived and its average lifetime, average number of pilot signals per transmitted message, and average transmit energy per message are simulated. SR strategy uses less number of pilots than selective cooperative relay strategies (S-CRSs). A dynamic transmit power threshold is adopted for the proposed SR strategy to improve its performances. In contrast to S-CRSs, in which each relay knows its CSI to the destination before every transmission, SR acquires CSI on the need-to-know basis and significantly outperforms the lifetime of S-CRSs for large number of relays and relatively good channel conditions. The proposed SR selects relay nodes in a distributed manner which makes it suitable for heterogeneous ad-hoc sensor networks in which some relays have processing capabilities and less restricted energy supply, i.e. these relays can act as the intermediate destinations.Scopu

The impact of authentic complex engineering design experience for k-12 students on 21st century attributes and perceptions towards STEM fields (Evaluation, Strand 3)

Recent studies showed that embedding engineering at K-12 level has a positive impact on stimulating interest in- and improving learning outcomes of science and mathematics, and development of 21st Century skills. Engineering activities are used as a way for displaying an authentic applicability of taught math and science in K-12 students in real applications. In this context, an outreach activity, namely Life is Engineering Program (LIEP) was launched in 2009 by the College of Engineering at Qatar University with particular focus on Qatari male students. In LIEP, K-12 students in the 10th and 11th grade work on assembling racing cars over a period of six months throughout an accompanying program of activities, engineering workshops and seminars, and finally a race is conducted in an international racing circuit located in Qatar. The methodology of the assessment included analysis of 2 surveys each of 16 questions (including demographics, open-ended, and Likert scale up type of questions). Surveys were delivered to both LIEP participating students (Sample no. N= 57) and LIEP non-participating Qatari students (sample no. N= 51). Experimental group outcomes against Control group outcomes were analyzed; findings indicate statistical significance in perceptions towards development of significant set of 21st century competencies. Perceptions towards STEM fields were more positive for the experimental group than the control group for the majority of measuring items, however statistical significance was detected in fewer items. The paper provides further details on the LIEP outreach program, as well as the assessment, its methodology and initial findings and planned actions American Society for Engineering Education, 2015.Scopu

Contributions of competition based complex engineering design experience to leadership development in engineering students

Engineering design activities provide students an opportunity to develop a number of skills. Engineering design experiences not only help students to acquire practical or technical skills, but also may enhance a number of soft (non-technical) attributes and competencies, little is investigated on the impact of engineering design on leadership development. Shell Eco Marathon (SEM) competition is a venue whereby engineering students compete on designing an energy-efficient car that is able to travel furthest given distance within a given time using the least amount of energy. The competition is composed of two categories: First one is a prototype oriented, which focuses on maximum efficiency while passenger comfort takes a back seat. The second category is Urban Concept class that encourages more practical designs. In this paper, analysis of contribution of a complex engineering design experience such as SEM on leadership attributes development is provided. This paper starts with a review on leadership attributes, as well as, recent developments and efforts of incorporating leadership themes in engineering education. Then an overview of the Shell Eco-Marathon competition is provided, with some details on historical background and global organizational structure. Methodology of the impact of SEM on leadership development is then highlighted, and detailed analysis is provided. Impact analysis of the SEM Design Competition incorporates evaluation of data collected through questionnaire with participating students. The paper then discusses students own opinions on leadership skills enhancement spanned over 3 main categories; personality traits, motives, and cognitive factors. The paper concludes with recommendations emerging from the investigation for engineering education academics and engineering curriculum developers.Scopu