On April 15th, Mr. Morasse’s Algebra 1 first and third period students visited the computer lab to solve “Quadratic Equations” using Matlab. They observed equations by plotting with Matlab’s “plot” and “ezplot” commands. They found the vertex and computed the axis of symmetry of an equation. Later they were introduced to the roots of the equation. We used “roots” command to compute the roots of an equation. The last Matlab command they learnt and practiced was “polyval” which allowed them to compute y points for known x points. They worked on a problem which required the steps they were introduced to solve quadratic equations using Matlab.
Megha Sunny, myself and Prof Thompson wrote a paper, titled ”Human Computer Interface Virtual Acoustic Display Using Gyroscopic Sensors” . This work was accepted for 14th IEEE DSP workshop and was published in IEEE proceedings. On April 14th, I presented our study to Mr. Iarrapino’s Engineering students. Engineering students, in general, are interested in engineering applications.
Our study is on modeling Head Related Transfer Function, its simulation, and using it as a real-time system by collecting head-angle data using a Wii-Remote Motion Plus device.
We had enjoyable time. during the presentation. The students listened the talk and responded. I really appreciated the effort they put into understanding and following what we are trying to accomplish. They seemed interested in our paper’s being accepted for a conference, the trip, the idea behind sound localization, idea of modifying headphone sound, mathematical modeling, and search for a low cost head tracking device. At the end of the presentation, we had the short demo on how the application looks and sounds like, and how its used.
On March 31st, Algebra1 first and third period students worked on a “Resonance” experiment in the physics lab as the part of “Waves and Vibes in Action” program.
We spent 15-20 min on the concept of resonance in a previous class. The objective of the experiment was to find the natural frequency (in our case it was the fundamental frequency. The students weren’t asked to find the harmonics) of air in a closed pipe. Another step (objective) of this experiment is to observe the standing wave, and its nodes and antinodes during the resonance.
GK12 Fellow Elaine Vejar was with us. She helped the students with their experiments, and answered their questions. Mr. Morasse and I appreciate her help. It was possible to give attention to each group.
Each setup had 3-5 students. Visual Analyzer was used both to generate sine waves and display the signals received by microphone. We used long pipes to keep the frequency lower. Each pipe had a speaker connected to one end. The other end was covered with a lid twith a small hole in the center. This allowed the students to use a long microphone ( a small microphone that is connected to a rod) to be pushed into the pipe to observe the waves in the pipe. The students increased the frequency of the generated sine wave till they observed the highest amplitude point. They calculated the wavelength using speed of sound and frequency. They were not asked to use the “2*length of the pipe” formula due to the damping effects. As the last step of the experiment they were asked to find the first node the microphone reaches during the resonance.
The experiments of the first period weren’t as successful due to partially ready set-ups before the students’ arrival. I summarized the expected results before the class ended since not all of the four groups had results. The experiments for the third period went very well. The students finished the experiments before the end of the class.
Freshman physics is currently on waves. Freshman students observed mechanical waves in their physics classes.
On March 10, we had a computer lab for Algebra 1 honors classes. The subject was “Waves on a String”. The students worked with an interactive software application that simulates wave behavior on a string. They had worksheets to guide them during the class. They were expected to make their own conclusions through this guided study. However, I tried to summarize the expected observations at the end of the class.
The link to the simulation we have used:
http://phet.colorado.edu/sims/wave-on-a-string/wave-on-a-string_en.html
I tried to introduce some new words, and their meaning during the class such as reflection, transmission, attenuation, boundary conditions, hard boundary, and soft boundary.
Students were to observe:
- The wave phase change of the reflected wave for fixed and loose ends.
- The wavelength times frequency is wave speed.
- The wave speed changes when the tension of string changes. Speed increases when the tension increases.
Students seem to like the class. Most of them put sincere effort in answering the questions on their worksheets.
Mr. Iarrapino’s engineering students were working on preparing presentations on African-American inventors. Most students were searching on whom to choose when I visited the class. I saw a student was reading about Jim West. I thought Prof Thompson would be happy to see that.
On March 3rd, Algebra 1 students studied “Edge Detection” in the computer lab. Students were introduced to steps of basic gradient edge detection. We talked about what is meant with edge detection, and why it might be useful. We thought about how we trace outlines ourselves, and how we can apply this to pixels. I described edge as a noticeable change in intensity. How could we find this change on a 3×3 matrix, as a subset of image? We went through the local average of sum of differences in x and y directions. After concept of total magnitude for rate of intensity change, and showing the results for a sample small binary image of a rectangle, the second step was using a threshold. Anything smaller than threshold was assigned to be zero and the rest – edges to be one.
This section was followed by experimenting Matlab image calls: imread, imshow, rgb2gray and edge. Because the algorithm they were introduced was Prewitt Filter, we used the same in Matlab. The students were asked to change threshold to see the results, but they did not have the time to apply it.
The first group of students did not getmuch out of this class as the second group. I did not realize they did not know what threshold is, and it needed further explanation. Also I knew some students, just kept typing from the print outs they received. After discussing my worries that the Matlab practice is not fulfilling its purpose with Mr. Morasse, he came up with a very good suggestion. During the second class, I had slides only for the theory section. For Matlab, we projected Matlab command window, and I entered what we were teaching. The second group of students were asked questions such as the next command, or the input arguments for the function. That went very well. I believe they learnt what was planned to be taught. We will follow the same format in the next classes.
On February 17th, we had a 20 min introduction and discussion on resonance and natural frequencies.
Our small discussion started with watching a you-tube clip on explaining how and why sound can break a glass.
The link to the clip: http://www.youtube.com/watch?v=JDnNmLkQ3Bc
Later we watched the Tacoma Narrows Bridge collapse. This was a silent and short clip. Students were asked to make connection between the bridge collapse and the breaking glass.
I showed the students a Barton’s pendulum that I had built. My version had 6 pendulums, including the driver pendulum. The driver pendulum had a heavier bob. The other 5 pendulums had two shorter pendulums than the driver, one the same length, and two longer pendulums. When the driver starts to swing, the pendulum with the same length string is expected to display the highest amplitude (largest back and forth path of motion). It was an interesting display. However, pendulums are very complicated really, although this design is there to serve the purpose. The set-up brings many other questions to mind (such as phase certain differences between the driver and driven pendulums).
I enjoyed working on it and displaying it though. Its was a mistake for me not to use much lighter bobs for the driven pendulums. They were supposed to be paper cups. I used light and heavy nuts (nuts of “nuts and bolts”). I got the idea from this web site:
http://www.fas.harvard.edu/~scdiroff/lds/OscillationsWaves/BartonsPendulum/BartonsPendulum.html
We reviewed the formula for pendulum period, and saw that the two pendulums with the same length string should have the same oscillation frequency. Therefore, the oscillation of heavier pendulum can drive the other to resonance, and that is the reason that it has the highest amplitude of oscillation. Although, this all sounds good little change in the display fails the point, and my very homemade pendulum was quiet fragile.
Hi all,
I am writing this in regards to our latest meeting’s subject at Lowell High. While I was driving home after meeting, I came up with some ideas, and I am hoping you can find them worthwhile to put in practice.
All the ideas about after school programs on certain subjects, and having exhibitions and demos of science and technical subjects such as nanotechnology, robots are great ideas. These can reach mostly to students who have some interest in engineering and science. It can show that science and engineering can be fun, and be educational.
However, engineering (I will talk about engineering since I am an engineer) has a missing link. I believe the way to repair it is to show its humanitarian side. I suggest a day or a week (better) of exhibitions that can be placed in Lowell High School cafeteria, with a theme “Be the change you want to see in the world” (of course this can be something else but I think the idea is : “It is time to pitch in”). The event can list challenging problems to be solved, but in an motivating way rather than depressing . There can be information on current projects, and stories from real people. I think Dr. Jack’s idea on a arranging science/engineering project competition was a good one, and can be part of this event. I will try to come up with more specific ideas. Young people can afford ideals, and should be encouraged to have them.
Algebra 1 honors classes are learning about systems of equations. On Friday, February 4th, the students visited the computer lab to learn how to solve “Systems of Equations” using Matlab. We used symbolic math, and ezplot. After introduction to symbolic math and an example, we solved a word problem. The students got little frustrated with their typos and not knowing what their mistakes are, but I believe this is a good practice.
Due to Winter Festival, the traffic on Thursday and Friday was bad. I left my home quiet early on Friday, and yet couldn’t make it on time. Mr. Morasse started the class without waiting too long for my arrival. Both classes finished the lecture somewhat on time.
Although, the workshop was a combination of DSP and SPE studies and lectures, I thought mentioning about two student studies in SPE session for the blog.
There were three student papers in the best student paper award lecture series. I would like to write about a couple of them.
I found the study “Teaching signal processing according to what your students know” by Geoffrey Herman (from University of Illinois at Urbana-Champaign) useful, and interesting. His paper collected his steps on his teaching approach and observations. The idea was to put together the best of online and in-classroom teaching. The short lectures were presented on You-Tube, with a short multiple-choice assesment. The lecturer went through the answers to these questions to understand what the students knew. The class time was spent to do the homework, and students were allowed to work in groups and discuss.
The second work is “An introduction to machine learning for students in secondary education” by Steve Essinger and Gail Rosenger (Drexel University). This study used Machine Language application to be used by students. The system catogirezesd the inputs. Students feed the system with features specific to the input (bactaria, coins, recycling material) etc. The output was the identification of the input’s category. I couldn’t understand how much students were involved in selecting and applying the machine learning algorithm. It seemed as an interesting work.
Uncategorized | Ayse Savoy | 
April 26, 2011 10:11 pm | 
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