lunes, 29 de octubre de 2012

Midterm Exam (IV)

Since 6.002x started, on September 5, I am writing a blog. Now that midterm exam is over, I would comment some measures I took during examination period. I decided to title some entries with the names: midterm exam and midterm exam solutions. I wanted to measure the impact those names had on our 6.002x community. The blog has had a very modest impact. However it has been constant along the weeks. Last entries attracted the attention of many people. Below, I would show some results. The numbers of visitors increase twentyfold.
 India, USA, Spain and El Salvador were the top four. If we consider population ratio, It is surprising that a tiny country like El Salvador (6M) could follow behind India (1200M), USA(300M) and Spain(46M). As I understand a round two dozen of our students are taking 6.002x. I know that very few students in three other universities are following the course. Also I am aware that some alumni are studying 6.002x.

But what were they looking for during the last weekend? Google's blogspot statistic gives a little hint. We see that searched words were related with finding the exam solutions. Some people even wanted specific solution to a given problem.

I understand cheating is stronger in some societies than others. I wonder if this experiment could stimulate values given in MIT honor-code. I would put some extra effort to explain students why it is important to be honest. MIT 6.002x could give us the pleasure to feel better about ourselves.

viernes, 26 de octubre de 2012

6.002x Midterm Exam (III)

Midterm exam was designed to take two hours. I did it in five hours. Before summiting, I double checked all the answers. I have to say I did not prepare myself an exam environment. I had several interruptions and my computer crash once. Below I will describe my timing.

Q1 took me 20 minutes. Rapidly, I jumped over Q2. Then I stopped for dinner with my wife. We watch TV and a friend of us came to the house. So I could only put an hour more, just for solving Q3 (51 minutes). I was so tired, my computer had a severe crash. So I decided to continue the exam next day. 

During this morning, I got stuck with Q4. It took me 1:43 minutes! In Q5 I found my first bug and I decided not to spend much time on it (15 minutes). I continued with Q6 and got my second bug (25 minutes). I had 94% of the exam completed in almost 4 hours. (Q1: 20';Q2: 33';Q3: 51';Q4: 1:43;Q5: 15';Q6: 25'). I spent one more hour chasing two small bugs; But could manage to get just one.

6.002x Midterm Exam (II)

Just a few minutes ago, I  finished midterm exam. I have to say, as I have already said in this blog, that I am retaking 6.002x. Last spring I got 94% in this exam. Today I could barely improve it by 3 points.  I left to the end two bugs to solve with only one chance on each one. But I could only get through one. So I missed my chance to get 100%.

To make a computer grading student exams will be challenging. This whole MOOC experience I have self imposed upon me is making me think about the way I grade students. I am a professor. Along my years of experience I have graded students differently. Let's take for instance the small bug that didn't allow me to get 100%. Probably, In my first years as a teacher I had not given 100% for not having a perfect answer. But now I am getting old, and a little bit wiser, I hope. Looking the way the way the solution has been approached, identifying the bug, I think I should had graded better.

Computeres can not take in consideration all those things professor take in consideration when they are grading exams, papers, and so on. But, wait a minute. Computers, after all, are programmed by professors. So It is just to find the way, to make the grader system better.

jueves, 25 de octubre de 2012

6.002x Midterm Exam (I)

Midterm exam has been opened. Thousands of people around the globe are going to pass through the experience of being tested on Circuits and Electronics. Different ages, different religions, different lenguages, different backgrounds, thousands around this planet have planned to be alone spending some time this weekend working with a computer.

I had  liked to take midterm today, the very first day. But today I have to make a trip to Bahía de Jiquilisco. We are guests in an opening ceremony. Our department, the electrical engineering school, has been working on a community outreach project. We have provided technical support to a photovoltaic electrification project. This year more than fifty rural elementary schools are going to have a very modest photovoltaic system. The very first school to have the new system is in Cantón El Cordoncillo, San Luis La Herradura Municipality. The school is in an island. To get there it will take many hours and different transportation systems.

See if after coming back from my trip I have the energy to start with midterm!

viernes, 19 de octubre de 2012

Vacuum Tube

I knew vacuum tubes did exist. Like I knew dinosaurs once populated the earth. I remember my seventh grade teacher doing the best he could to explain to us evolution and dinosaurs. However, regarding vacuum tubes, nobody took the time to explain to me the part they played in the electronics evolution.

It was a big surprise to see them in 6.002x. In  a week six's tutorial there was an example with a vacuum triode. I must confess I did not understand its purpose. Gerald Sussman explained that they are used in special applications. I thought those special applications do not play a need on our electrical engineerings. However I though it could be interesting to show students how a vacuum tube works.
I asked our technicians if they kept on stock any vacuum tube. To my surprise, they had plenty of them. Also there was an old vacuum-tube amplitude modulation receiver. So we decided to restore the receiver. It is not a easy task. Today we think we have done a lot of progress. We download the schematics. We look for the tubes. However we still have to find three more tubes. Probably we are going to buy them through eBay.
Regarding this effort, I cannot help to quote Lawrence Summers words: "Part of universities's function is to keep alive man's greatest creations, passing them from generation to generation." Vacuum tube was one of electrical engineering greatest achievements in the past century. Ignoring Vacuum tube it is to ignore one of engineering's greatest creations.

Educational robotic from Ahuachapán

Ahuachapán is the capital city of a department with the same name. It is located in western El Salvador. It holds borders with Guatemala. Ahuachapán has been know for the international geothermal community because since 1970 holds a geothermal power plant. Since a years back, Ahuachapán has done a tremendous effort to attract tourism. Two small countryside towns have started to build a reputation as tourism destinations. Concepción de Ataco, or simply Ataco, has grown a successful tourism industry.  Behind, Apaneca is following the same path.

This week we invited an alumni who has started up an educational robotic business
and an online shop. They are located in Ahuachapán city. They are not producing only software but hardware.
The project called the attention of the geothermal company in Ahuachapán. Their public relation department decided to hire them to give a robotic course for kids. Around twenty school kids have been studying robotics with the software and hardware developed in Ahuachapán.
Almost at the end of the presentation, Vladimir, our former student, told us about how he got to know python (the programming language he has used to build his software). He told us he got to know it in a talk. Like the very one he was given. The difference was that years back he was the young student.

jueves, 18 de octubre de 2012

Women in Engineering (III)

We had the chance to visit again Centro Escolar España. This time We did not have to ask for an invitation. We were asked to give a talk on electrical engineering and to do experiments with electricity.  They gave us a tougher group of girls. Teachers gave us two groups of eighth graders. It was not easy to keep their attention. But when the moment to experiment with electricity came, everything change.
Girls were very enthusiastic about our experiments with electricity. We try made them to interact with our live demonstrations. We took with us an antenna training kit. We showed them the power of electromagnetic energy. Perhaps, the very same experiment Nicola Tesla performed at the end of the nineteen century. 
This effort requires a lot of logistics. We have to carry with us electrical cords, projectors, laptops, lamps, solar panels, circuit boards, and so on.

Normally we begin given a powerpoint presentation. But I have noticed that this has very little if any effect. Girls want to watch us acting as magicians. They want to participate and prove to other peers how brave they are.

martes, 16 de octubre de 2012

Women in Engineering (II)

Today we visited our university radio. We came to talk about several of our initiatives. First, We talked about our project of visiting junior and high female schools. The IEEE student branch has adopted this initiative.For all of us, It was our first experience talking in a radio show. Sometimes, It was a bit claustrophobic. But In general we manage to deliver the message.

Below in the picture, Daniel and Fredy are waiting the beginning of the interview.
We still don't know the impact our effort will have. But one thing it is true, things are not going to change if we  just ignore them. Below, Mauricio talked about the IEEE, university student branch, and the different projects they are working on.
Tomorrow, again, We have to visit a middle school. We have to continue talking about electrical engineer. We are ready to introduce new experiments.

sábado, 13 de octubre de 2012

Is it different this time? (II)

  I am a very skeptical person. I have started to reflect on our own experiments in distance education; experiments that have been carry out here in El Salvador. I recalled that starting my middle school years I used a collection of books called Televisión Educativa. I found out it was the biggest project this country has carry out on distance learning. Héctor Lindo-Fuentes, in a paper entitled: Educational Television in El Salvador and Modernization Theory, describes the project. Also, in his new book, through the perspective of Modernization Theory and using the cold war as a context, Héctor Lindo-Fuentes describes the Televisión Educativa experiment. It had as a laboratory the tiniest nation in Central America.
Héctor starts his book with a story that took place on July 7, 1968. President Lyndon Johnson visited El Salvador. He came to meet all centralamerican presidents. He announce the patronage of Televisión Educativa. And he made a boastful declaration: "you have already made the beginning to being the first nation in all the world with a complete educational television system. And some day we hope the United States can catch up with you."

 I asked Héctor if he sees any prospect of impact in this new dynamic of MOOC.
He said: "I do not think it is a panacea that can easily dismiss the classroom quality. Moreover, it is one thing to teach undergraduate and graduate students. And it is other thing to teach the first years of school". He added: "In short, I think if the instrument is used properly and it is flexible enough to understand their limits much can be done with the remote computer education."

Is it different this time? (I)

Big Bird has recently appeared on the presidential campaign in the USA. An op-ed columnist wrote an article in defense of the big yellow bird: Don’t Mess With Big Bird. Rick Santorum's comment on the Yellow Giant, also called my attention: ‘You can kill things and still like them’.
  Today I did a google search on Big Bird. I discoverd that the bird I once watch on TV was a mexican version. It was called Abelardo Montoya. He was a green, full-bodied Muppet parrot. Plaza Sésamo was a Mexican co-production (1981) of Sesame Street.

  However, the name Big Bird was foreign to me. I barely recalled Sesame Street. What I really remember are my childhood days in the coffee plantation. The place where we grew up as campesinos. Working for the land lord who sponsored our school.
At school, In 1983, when I started Tercer Ciclo, Junior High, we had a TV. I barely can remember us using it. The TV was an inherited from a fifteen years old project. The project was called Televisión Educativa and it was run by the ministry of education.

I do not have any memory of the lectures they made us to watch. But I remember one thing. My aunt, the woman who raised me, and I climbed up San Salvador Volcano. We were looking for second hand books. The ones that support  the TV programs. In the coffee plantation we did not use the concept of going to  a book store to buy books. We asked neighbors through the plantation and through others coffee plantations who had previously used the books. Each neighbor we asked for made us to go up and up through the volcano. I do not remember if that day we had success. But,  I remember that we got the books.

By 1983, Televisión Educativa probably was dying. Years later, I remeber myself browsing through Televisión Educativa books. Sadly, finding that we covered barely half of the material.

Television Educativa started as a project sponsored by Lyndon Johnson's administration. It was a very aggressive project which involved Stanford scientists. Even Big Bird played a part on that iniciative.

viernes, 12 de octubre de 2012


Juan is one of our two technicians. He joined the electrical department back in the middle eighties. He is very skillful with his hands. He is very good finding bug on hardware. Today, meanwhile we were preparing next week experiment, I portrayed him with my camera.
The lamp, he uses to work, looked like a kind of heiligenschein, a saint crown. The picture made me think about Juan's character. He is an extremely naive person who would never harm anybody. He is a very helpful technician. But we have to find the way to keep him motivated.
I asked him to help me to prepare an experiment for next week. And he found in the experiment a way to prove me he knew many things about vacuum tubes.

So for next week experiments we are going to resuscitate vacuum tubes that have been kept in stock for more than three decades.

martes, 9 de octubre de 2012

Dead or alive!

As a way to keep Circuits and Electronics alive I decided to publish a fake old west poster. As a joke, I offered one million dollars for whom could resolve homework H6P2. I do not know if somebody will take the poster seriously. But, what I really hope is to called 6.002x-ers' attention.
H6P2 is very interesting in itself. It shows the way to have resistor using a transistor. As a consequence, it shows the way to reduce the size of consumers electronics.

sábado, 6 de octubre de 2012

Small Signal

It has been four weeks since Circuits and Electronics started. I have noticed that some students have given up. There are others that are doing a terrific job. But there is a group that are on the verge to give up. In order to help them I organized an open exposition with experiments on small signal. In addition, I wrote on paper the exercises that were published as tutorials in week four in the first 6.002x. All the exercises were published on a wall so students could look at them.
Also, I had the idea to explain the small signal concept using a LC circuit as a frequency demodulator. We generate the FM signal using two old signal generators---one as a carrier and the other as a band base generator. We use an LC amplitude modulated tuner.

In addition we used a thermistor, as part of a wheatstone bridge, to illustrate the possibility to measure microwave power.
I have noticed that public demos have attracted the attention of our students. I have started to call it nomadic circus approach.

Women in Engineering

Last Wednesday we started something, we hope, it could be a long term program. We visited a neighbor school. In two shifts the school hosts around 1200 female teens. Almost 600 students for each shift. The name of the school is Escuela España. It is a kind of Middle school. It works as a junior high school.
Several months ago, I proposed to some students at our department to start a program for encouraging women to study electrical engineering. There were several ideas on the table. We discussed whether to focus on girl schools, mixed schools, elementary schools, middle schools, high schools, public schools, private schools and so on. I proposed them to focus on female middle schools. Beyond to encourage the study of electrical engineering we want to encourage the study of math and sciences. In my opinion, to do that at high school level will be to late.
We also talked about if this idea could be framed among the IEEE student branch initiatives. We agreed on that. Also, students will fulfill their university mandatory social outreach.

The school principal sent us to talk to senior middle school students. Not all of them will continue studying high school. Probably half of them will continue studying. Perhaps less than a quarter of them will finish high school. For those who are going to continued in high schools they have to make a choice. The salvadoran high schools system has something called bachillerato técnico which gives basic professional  training to students.

So if this female teens are attracted for the study of engineering they could enrolled in high schools that give training in electricity, computer, electronics and so on.

The experience to communicate the electrical engineering field to female teens was new for everybody. But in general everything was ok. Teens were very motivated. Electrical engineering students were open to explain every question that was asked at them. Also teachers asked us to come back next week.