PA4: Contributed Session

Room: Old Main Academic Center 3090

Webex Link

Chair: Ghodsieh Ghanbari

Diana Andone, Politehnica University of Timisoara

Time: 4:00 pm - 4:20 pm (CST)

Title: Educational Activities for Students’ Computational Thinking Skills


During the past decades, many university educational activities in information and communication technologies have evolved from strictly developing computer programs to solving problems creatively using computational thinking skills. Assigning students to create visualizations, design multimedia, analyze data, perform simulations, and navigate online content are among the several tasks from which students can understand and experience underlying computing concepts. These tasks train students to develop skills in computational thinking. This paper describes several educational activities developed by the Politehnica University of Timisoara (UPT), Romania and one jointly with Bentley University (BU), USA.

TalkTech is a learning collaborative study, which since 2008, has paired students enrolled in a first-year introductory technology course at BU in the United States with fourth-year multimedia students from UPT in Romania, to research and discuss current technologies and create digital media artifacts (from website, to augmented and virtual reality) that develop computational thinking and digital literacy skills. International Digital Media Student Contest is run yearly, since 2016 by UPT and encourages students’ development of out of the box, interactive applications in graphics, websites, mobile apps, Internet of Things, audio and video production areas.

At the end of these activities, students answered surveys and participated in focus groups. Some, returning after years into the university as alumni, mention their development and career choices, influenced by the computational thinking abilities they gained during these extra-curricular activities. The paper analysis these results and presents further possible ideas of our study on how different education activities influence students’ abilities.

(joint work with Mark Frydenberg and Radu Vasiu)

Sebastian AvramPolitehnica University of Timisoara

Time: 4:20 pm - 4:40 pm (CST)

Title: Design and Development of 1st and 2nd order differential filters using numerical simulation with Scattering Parameters


This article presents the design and development of 1st and 2nd order differential passive filters using scattering parameters (S-Parameters). The main motivations for designing and developing these filters are: the need of conducted noise filtering for medical devices in the context of strong conducted EMI (Electromagnetic interference), conducted noise filtering for devices that might interfere or are affected by power line communication (PLC) and there is no article which approaches this subject completely and detailed.

In the design phase of the passive filter, we have measured the components (inductors and capacitors) using a vector network analyser (Touchstone® files) and we have used S-matrix parameters for numerical simulation (matrix calculation). In the development phase we have built and measured the filters. The measurement results are similar with the numerical simulation/ calculation.

The following filter properties and characteristics are in the focus of this article

- Attenuation/ Transfer characteristic

- Cut off Frequency

- Input and Output Impedance

The design and development methods presented in this paper can be extended to filters of higher order.

(joint work with Radu Vasiu and Stefania Avram)

Mircea Gurbina, Politehnica University of Timisoara

Time: 4:40 pm - 5:00 pm (CST)

Title: Exact Mathematical Analysis of dc-dc Converters Employing PID Controllers


A new method for analyzing dc-dc converters stability in closed loop operation is developed. A generalized discrete model is proposed consisting of two nonlinear vector equations: the state equation and the nondynamic constraint. After model linearization, the classical technique using the characteristic multipliers can be applied. Several problems were solved regarding:

1. The nondynamic constraint derivation

2. The steady-state operation point calculation

3. Verifying that the parameters defining the steady-state operation point are located in the linear region and are not in the proximity of a saturated vicinity

4. Partial derivatives determination and Jacobian calculation

The above concepts have been easily implemented in MATLAB® allowing:

1. Determination of the parameter value for which instability occurs

2. To demonstrate that instability is installed with a Neimark-Sacker bifurcation.

3. To prove that the proposed exact method predicts a much larger stable region, 327% higher compared to that predicted by the traditional approach. This is important because it allows designing a significant higher bandwidth controller, with improved dynamic features

4. The method can be applied to any dc-dc topology

The theoretical considerations were accurately validated by computer simulation.