On Teaching Programming in the Age of the Web

In the last few years a lot of people have been pushing the idea of 'flipping' the classroom experience: have the students view online videos as the homework then use class time for one-on-one help, see, for example, Kahn's video below. I agree it's a great idea, and there is data to support it, but can we do that when teaching programming to University students?

In the last couple of years I have tried to do this for two of my classes. My CSCE 145 is our introduction to programming class. It is taken by both computer majors and non-majors, about 50% for each group. My section alone had about 60 students. I created some Java programming videos which the students could watch at their leisure. With about 60 students, personalized in-class help was not possible, also because the classroom had no computers and the vast majority of students do not lug around a laptop all day with them. So, instead I decided to make the lectures more of an interactive demonstration: I would solve some programming problems in front of them and stop often ask them "how do you solve this?". The class also had a couple of weekly labs where the 60 students were broken up into more manageable groups and the TA's gave them individual help on the programming problems. I learned a couple of things.

1. The videos were watched by about 2/3 of the class. From the surveys I gather that the students that did not watch them where those who already had programming experience; they didn't need them. Thus, the videos were a success, mostly. Looking at the logs I see that the first video was watched the most, then the second one, and so on. So, some students stopped watching. I think I made the mistake of making them about 40mins long each (I wanted to cover 1 chapter in each video). Next time, I will follow Kahn's lead and keep them under 10 minutes and limit each one to more specific topics.
2. The lectures, in which I do a sample programming problem, seemed to be well received, but attendance was still just around 50% (students did not get penalized for not attending lecture). I think it would be more effective to get rid of lectures completely and have more labs, but this would mean I would have to spend 24 hours/week just in lab (12 hours/group with 2 groups of 30 students), so it becomes a significant time commitment. Add to that the time I spend making videos, tests, and homeworks and it quickly becomes 40 hours/week for just that one class. I think a more realistic solution is to pay some of our A-level Seniors to do some of that coaching, but we don't appear to have that kind of money right now.
3. IM works really well. If you to the class blog you will see the "Chat with Jose M Vidal" button. This, along with a pastebin were very useful. For whatever reason, students will not email me their questions, but they will hit me up on the IM. This was a great way to offer when-needed help. At this level students often get stuck with a simple problem, like a missing semicolon or a variable defined in the wrong scope. A student could spend hours trying to figure this out while I can just look at it and in two seconds solve this tiny bug so they can move on rather than giving up out of frustation, which is what many times happens (and then they drop out). With IM they could just send me their pastebin link and I could solve their problem, any time during the day. The only problem was that our schedules are rather off-sync: I sleep from 10-6am while they appear to sleep from 2--10am. Luckily, my TA was able to pick up the night shift.

In my CSCE 242 class I am teaching web applications which is a topic for which there are a lot of online instructional videos. The problem there is choosing which of these videos are good, and deciding on which ones to show at which time. Since this is a software development class, I structured as very heavy on the programming. The class consists of about 13 programming homeworks that, more or less, have the student build a modern complex web application. The class is not yet over, but already I see that:

1. IM has been even more useful in this class. I get at least a couple of question every day.
2. The best help is context-sensitive. Complex programming ideas are easier learned in context. When I grade one of the homeworks and I tell the student "I see how you did this, and it works fine, but look at this other way of doing it. Isn't it soo much simpler?" the lesson is readily learned. At least, that's how it seems to me. I wish I could get some data on this.

Going forward I hope more people like Kahn step up and produce more of these videos. In fact, I want to see better videos with animations, professional voice-overs, professional writers, etc. These videos will be our new Public Library. They will allow me to focus on proving the context-sensitive help that students need. I also see that teaching will continue to move away from 9-5 and become more of a 24/7 on-call type of job. Hopefully, we will have shifts!

Sending Emails from a Google Spreadsheet

I have been using Google Spreadsheet to keep my class grades for a couple of years. It has several advantages over the PC version:

1. I can share the spreadsheet with my TAs so they can enter grades for their labs. We are all always on the same page.
2. Google spreadsheet keeps track of all old revisions, so if any one of us makes a mistake we can always go back to see what the original grade was.
3. It is trivially easy to create a graph of the grades and post a link to it on the class blog. The graph gets updated automatically as the grades change.

However, one remaining problem was how to give each student his grades without revealing all the grades, which our university frowns upon, even if the names are not posted. The clear answer is to email each student his own grade.

Luckily, Google has a cool feature called Google Apps Script which lets one write JavaScript programs that can access the data on a Google doc and do things like send emails. So, I wrote a short program to automatically send each student his grades.

Installation

To use it you must first set up your grades spreadsheet to look like this one. Note that

1. the first row has a 'name', 'email' and other columns for each item,
2. some columns have the same name as other columns, but with ' Comment' appended, for example: 'Test 1' and 'Test 1 Comment', the comment columns contain any comments you want to give the student
3. the sheets are named 'grades' and 'template'
4. the 'template' sheet contains the template information for building the emails (your message).

Once you have the spreadsheet built, go to 'Tools -> Scripts -> Scripts Editor and cut-and-paste the emailgrades.js script in there. Save it, then close and re-open the spreadsheet (or, run the onOpen method if you know how to do that). You should now see a new menu item on you spreadsheet called 'Class', as shown in the screenshot.

Usage

The 'Send Emails' item will send each student (row) his grades if you choose it when you have no cells selected. If you first select (light blue background box) some cells in the spreadsheet then it will only email the students in the selected rows. You can verify that the emails have been sent by going into your gmail account and checking the 'Sent Mail' folder. It can take several minutes for the emails to start appearing so be patient.

The 'Preview Emails' item is mostly for debugging. It will show you a preview of two of the emails that send emails would send. The 'Show Email Quota' item tells you how many more emails you can send today. Google limits scripts to 500 emails per day to keep spammers from abusing the system. Since my classes have at most 60 students this has not been a problem for me.

If you have any comments, bug reports, or feature requests please post them below.

Resiliency in Supply Chain Networks

Andrew Smith and I have been looking at the problem of resiliency in supply chain networks. That is, given the fact that supply chains are formed by selfish agents who create links with others based on their own local interests, we cannot expect the resulting network to always have the optimal resiliency characteristics. It is quite possible that because everyone is acting myopically—agents care only about their immediate neighbors—that the resulting network will have some bad global properties. The global property Andrew studies first is resiliency, which we define as the ability of the network to withstand the loss of one node.

Andrew presented his paper titled A Practical Multiagent Model for Resilience in Commercial Supply Networks at the latest Agent-Mediated Electronic Conference. He implements a model which generates supply chain networks based on a well-known model from management theory, so the networks' topology should match real world networks, and then examines the resiliency of the resulting networks. The results are not surprising in the general sense (more connections mean more resiliency) but they do give us a quantitative measure of network resiliency.

Below are the slides from his presentation:

Software Engineering Projects

I am often surprised at what a small group of our Senior Computer majors can accomplish in one semester, while taking four other classes, looking for a full time job and, in many cases, also working a part time job. But, they do some pretty amazing things in my CSCE 492 class.

The first group this semester decided to build an iphone app. None of them had any experience with the Mac, or objective-C, or the xcode IDE, nor did any one of them even own a Mac! Still, none of this matters much. They quickly came up to speed on objective-C (which has similarities to many of the languages they learned in other classes) and managed to build a game that is better than many of the games in the app store. I expect their skills will be much in demand. In fact, I know they are.

The second group built a Ruby on Rails applications that interfaced with the Amazon and the Facebook API's and used mysql, jQuery and had other javascript niceties. Only one of the students had experience with Ruby on Rails, and none had used web APIs before. It was another large learning and doing experience.

Still, aside from the technical knowledge they acquired, what they always tell me they learned most is how to work in a team and coordinate their time so as to get large projects like these done. That is not something that can be learned in a lecture.

SeaPort Container Terminal Simulation

Next week I will be presenting our (with Nathan Huynh) paper on agent-based seaport container terminal simulation at the workshop on agents in traffic and transportation.

Basically, we used netlogo to build a simulation of a container seaport terminal, like the one you see on the photo. We focused only on the decision-making process of the cranes. Those large cranes you see have to pick up the containers and place them on the trucks as they arrive. Since the cranes are slow and there are many trucks the crane operators have to trade-off several competing interests when making their decision: trucks want to get out of there as quickly as possible, it takes the crane a long time to travel the length of the seaport, the port manager wants to maximize the number of trucks served but without making any one truck wait too long.

In this paper we tried the more obvious utility functions to see how they performed in a seaport with 2 or 3 cranes. The utility functions used are:

1. distance-based: roughly, go to the nearest truck, but avoid getting on the way of the other cranes,
2. time-based: roughly, serve the trucks on a first-come first-serve based, while trying to stay out of the way of other cranes,
3. a mixture of the above two.

Test results showed that the distance-based won, by a lot. It won not only on the throughput, as it obviously would, but also on the fairness measures, which is not so obvious.

I'll be putting up the netlogo model on my MAS Netlogo models page soon. The slides from the talk I'll deliver on Tuesday are below:

We are currently working on expanding this model, both from a programming, simulate more parts of the supply chain, and the analysis side, put some bounds on the solution quality that can be achieved assuming local control and local information.

What We Should Teach IT Students

Yesterday I attended POSSCON where I saw a talk by Andy Lester on "What We Should Teach IT Students". As the use of the word IT in the title reveals, the target audience for the talk was enterprise developers.

For readers new to the field, enterprise developer is just a type of job. The easiest way to define the term is by pointing out that Blue Cross Blue Shield and Bank of America hire "enterprise developers" while Google, Microsoft, and Valve hire "software engineers". That is, enterprise developers write the software that makes the business run smoothly—process insurance claims—while developers write the software that IS the business—the new version of Windows. From an accounting point of view, enterprise developers are often a cost center for the company while developers are a profit center.

Still, the recommendations are largely applicable to all. He recommends students learn:

1. Source control
2. Bug tracking
3. Compiler (paying attention to the error messages)
4. Make and the philosophy of repeatability
5. Lint / splint or similar static code analyzers
6. Serious editing
7. DRY: Don't Repeat Yourself
8. Defensive programming
9. Maintenance: working on other people's code
10. Manual testing
11. Automated testing
12. Efficiency and why it does not matter
13. Thinking about the: business, project, release, deadline (getting the bigger picture)
14. Teamwork: work well with others

Our curriculum covers all of these, some more than others, and I am in full agreement with all of them.

Some of these, however, I think must be left mostly to the student. I know that learning to use the editor is super important, but I don't think we need an actual class to teach editing! I really can't see myself standing in front of our students for a whole semester telling them "To compile your code, press F8; to indent your code press Ctrl-A then Crtl-I". They know they can just get the list of shortcuts and memorize the ones they need. Still, I do make a point in my classes to stop and explain how I got System.out.println to appear after just typing sysout. Similarly, learning to use a source control or bug tracking system is just not that hard (compared with, say, implementing a compiler). Overall, the students who have not learned to use their editor, or understand compiler errors, or DRY, are generally the few who really don't care about programming, and their grades show it.

Still, I agree that these are all important skills to have.

Andy also said all students should have read Code Complete, which is the required textbook for my 492 class. He also mentioned The Pragmatic Programmer which is also a personal favorite of mine and on my list of recommended books for 492. Of course, we all know they are good because stackoverflow says they are.

Multiagent Systems Introduction

Last week it was my pleasure to give an invited talk at Temple University, part of their Robert M. and Mary Haythornthwaite Foundation Distinguished Lecture Series. I tried to provide a high-level overview of multiagent systems is all about, which is always a huge challenge as the field covers a lot of disparate areas. After some thought, I decided to pick three applications and

1. describe all the issues relevant to the problem,
2. show how we use theory (either algorithms, game theory, or Economics) to get a better understanding of the underlying issues,
3. explain how there is still much engineering that needs to be done because even the best theory or algorithm still millions of details, and software is just a collection of details.

For posterity sake, below are the slides I used. The slides contain as little text as possible, which I think generally makes for a better talk.

Learning Java Videos

Last semester I taught CSCE 145, our introduction to Java programming class. For that class I created a set of videos that teach the basics of Java programming using Eclipse as an IDE. The videos were very popular with students, especially those really new to programming. So, if you are a student interested in learning to program, go check them out.

CSCE 145: Chapter 1: Introduction to Java from Jose Vidal on Vimeo.

Current Research Talk

This Friday at 2:30pm in 300 S. Main B102 I will be given an informal talk about our current research projects for our CSCE 791 class. This is open to anyone else who is interested. It will be a long rambling and highly disorganized version of my previous 7 minute talk.

Ongoing Research Projects

Every year our department has 7-minute madness presentations in which we faculty present our ongoing research. It is a great opportunity to hear about all the innovative research going on in our department (especially in the area of multiagent systems, of course :-). The slides from my 7-minute talk are below.

For those of you who could not make it, and since I ran out of time after just a couple of slides, I write a bit about each project below.

We have a lot of papers published on distributed combinatorial auctions, especially on bidding algorithms for the PAUSE auction. This work was done with Benito Mendoza who received his PhD in May and is now working at Exxon on multiagent simulations. I continue to work on this topic but with a slightly different focus: viewing these distributed auctions as negotiation networks.

The iCoach project is with prof. Sara Wilcox from the department of exercise science. Chuck Burris, and undergraduate, has been developing on the Google App Engine a webapp that will send customized SMS messages to users by first gathering information from the user's phone, pedometer, and online information (where he is, via GPS, how much he has moved, via pedomenter or accelerometer, what his plans are, via his google calendar, etc.). There is a lot of information about us on the net, and the new smartphones will give us even more. However, aside from collecting and displaying this information back to the user in a pretty graph, there has been very little research done in to how to use this information to improve our lives. That is what we study. Our initial system is being designed to monitor, educate, and coach first-time pregnant women.

The wikitheoria is another Google App Engine webapp we are building, and by "we" I mean Jon Mayhak and Jason Rikard. The project is with prof. Barry Markovsky from the Sociology department and can be summarized as "wikepdia meets stackoverflow for sociologists, with added semantic structure". Our goal is to build a site that will enable and encourage sociologists to post their models using a common ontology (set of terms with agreed-upon definitions). The common ontology will also be developed on the site. The current site is currently being tested by forcing a graduate class of sociologists to use it.

The port simulation project is very new and its joint work with prof. Nathan Huynh from the department of Civil Engineering. Nathan is an expert in ports and trucking problems. In our initial collaboration we are looking at the problem of how the crane operators in a port should act or cooperate. The job of a crane operator is to pick up those big containers, one at a time, and put them on the trucks as the trucks arrive. The containers can be stacked up so sometimes the crane operators have to do some re-stacking of the containers, which wastes a lot of time. We are building an agent-based simulation of this problem and trying to find best strategies for the operators.

Andrew Smith is a new PhD student who has already written a paper on supply chain resiliency. Using standard models of supply-chain formation we generated sample chains and then tested these topologies for resiliency to single-point attacks. That is, if one node goes down how does that affect the network as a whole. In the paper (not yet published) we present a numerical measure of resiliency and our test results show how it varies given the number of relationship resources (a measure of sociability) and size.

Andrew is also continuing his work with Karim Mahrous from Sandia National Labs on media dispersion and influence as part of his PhD thesis. This is another agent-based modeling project, albeit a much larger one for which we only have to develop small parts of the code, which aims to model how news travels in a social network. The project will cover everything from broadcast media, to multicast media (twitter), to one-on-one via electronic (SMS) or good ol fashioned conversations over lunch.

So, if you are a graduate student and find these ideas interesting, you can sign up for my Multiagent Systems class in the Spring which will cover the basic background knowledge needed to build, and understand, multiagent systems. If you are from a funding agency or company with a few bucks to spare for research, I would love to hear from you!