Farrokh Attarzadeh

Comparative evaluation of laboratory teaching in an AC Circuit Analysis course

The AC Circuit Analysis course is a requirement for electrical engineering and electrical engineering technology curricula. In the traditional teaching method, concepts are introduced during lectures. The students conduct experiments to observe these concepts during laboratory. Recently, new techniques based on the CLABS model developed at University of Houston (UH) that rely on real-world problem-based laboratory experiments have been adopted at Texas A&M University-Corpus Christi (TAMU-CC). In this paper, a direct comparison between the traditional method and the new CLABS method within one class at TAMU-CC is reported. The results obtained at UH are presented for a comparative evaluation. The results from TAMU-CC show that CLABS experiments are perceived to have a higher learning impact in new practical applications. Results obtained at UH show high student satisfaction in most aspects of the CLABS pedagogy. This work also revealed challenges in within-class comparative studies.

On optimal defibrillating pulse synthesis

This article proposes a control framework suitable to study the synthesis of electrical signals that bring a flbrillating heart to a nominal (deflbrillated) state so that regular, autonomous cardiac activity resumes. A parallel resistor/capacitor (single RC-circuit) and energy source has been used for over 70 years to describe the hearts deflbrillated state as a condition of reaching nominal threshold potential values represented by the capacitor voltage. The bidomain model adopted in the 1990s was an improvement as it provided 2D and 3D continuum models of cardiac tissue enabling significant advances in modeling electrical cardiac activity. We have spatially discretized a version of the bidomain equations so that the temporal behavior of the transmembrane potential at a point is deduced from an infinite number of first-order differential equations. The connection to a network of RC-circuits is logical and creates opportunities for theoretical and practical modeling and control contributions. A strategy that minimizes a weighted time/energy cost for the single RC-circuit was applied to a multi-RC model. The proposed pulse is agile and energy conscientious thus outperforming the pulse developed to minimize energy consumption alone. The results can also be used to formalize ad-hoc reports that explore the time-energy tradeoff in other defibrillating pulse candidates. In addition, the multi-RC circuit may be used to explore cardiac tissue recovery and multi-path defibrillation. A minimum-time strategy is proposed for the multi-RC circuit to address fast capacitor discharge requirements. These efforts suggest new waveforms to potentially innovate defibrillator design using feedback control.