OMG!  I got pulled off my usual job of doing a bunch of things and have been focused on getting students involved in the Imagine Cup Software Design Invitational in the United States.  Then it was Christmas and I ate to many cookies, etc.  Finally I ignored my one comment from a int19h, and when you get as few comments as I do, everyone is precious!

Int19h ask about my previous blog:

"This is one of the differences between functional programming (F#, OCAML) and imperative  programming (C#, VB.NET, Java), the concept of identifiers is not really supported in the imperative languages, although there are constants.

Can you explain what you mean by "the concept of identifiers is not supported"? Try as I might, I cannot parse this in such a way as to produce some meaning."

Fair enough int19h, just what in the heck was I saying?  Well, if I had wrote my next blog on the day I thought about it, instead of focusing like a laser on getting the students involved with Imagine Cup (hopefully my manager is reading that!).  The concept of the identifier in F# could be explained with this quote from Chris Smith's blog entry,  F# in 20 Minutes:

"...using the term ‘value’ to refer to identifiers rather than ‘variable’.  The reason for this is that types in F# are immutable by default, meaning that once they are created they cannot be changed. This may seem like a severe limitation, but immutability actually prevents some classes of bugs. In addition, immutable data is inherently thread safe meaning you don’t need to worry about sync locks in order to make your code parallelizeable."

 

What is an "Identifier"?  Identifiers give names to values in F# for reference later in a program.  You would use the keyword 'let', in the following manner, no semi-colon:

let x = 15

When a value is assigned to an identifier, it never changes in a functional program. The style is to refer to this construct as identifiers and not variables, see the book "Foundations of F#", by Robert Pickering.

Functions and Values in F# are treated exactly the same, also, functions in F# supports passing less arguments than the function supports, which is referred to as partial or curried functions.   For more information on this see  this excellent Podwyski's blog entry.

 

Are you interested in loading up F# and Visual Studio  but don't want to buy or load the full version of Visual Studio?  This is a great way to learn about the Visual Studio Shell and to get started with F#, if you have VS Pro or VS team system, then you only need to load up F#, unless you want to add Visual Studio Shell to your development tools, go ahead and load it.

First download and install the Visual Studio Shell:

Microsoft Visual Studio 2008 Shell (integrated mode) Redistributable Package

Then download and install F# CTP:

Microsoft F#, September 2008 Community Technology Preview

Have fun, make sure to check out the various blogs out there, so much good stuff, so little time!

F# has many interesting features, such as the use of lists, maps, and so forth. There are many blogs and websites dedicated to discussing the computer science side of F#, and for good reason the language supports these types of efforts. However, what about the rest of the computational users, for instance engineering students who are studying physics and want to generalize their homework problems in case they can use them when they are interns or are working after the leave school. After all, the homework that you do does serve a purpose other than getting a grade in class.

Please note that any discussion about using F# in my blogs are simply to illustrate the use of F# and not to make a statement that it is better than any other language or system such as Mathematica or Matlab, in fact F# is designed to work with those products as a friendly kind of language.

To get started, let’s take a look at how one F# can be used a very basic Ohm’s Law problem.

Let's take a look at a simple problem of electrical resistance.

Using Ohm’s law, Voltage= Current divide by Resistance or V=IR. If we know the total resistance and voltage, then current equals voltage divided by total resistance.

Let's use a circuit made up of three resistors that equal 40 ohms, 50 ohms and 60 ohms that are connected to a voltage source  of 3 volts. To determine the current then I would divide the total voltage by the total resistance.

• The equation would look like: current = voltage/(Resistor1 + Resistor2 + Resistor3).

Let’s write a simple F# program and a C# program to do the calculation:

Both sets of code look pretty much the same, and if we want to use it to solve circuits, we would have to insert the new values every time. In the next blog entry, we will take a look at using Excel for our input system.  It isn't pretty, nor is it practical, but it does give us a basis of a simple application that can be built on over a number of blogs.  Like many academic

F# form of the calculation (Formatting is correct)	C# form of the calculation (Formatting is correct)
#light open System let v1=3.0 let r1=40.0 let r2=50.0 let r3=60.0 let i1=v1/(r1+r2+r3) Console.WriteLine(i1) Console.Read()	using System;     class SeriesResistance     {         static void Main(string[] args)         {             double v1 = 3;             double r1 = 40;             double r2 = 50;             double r3 = 60;             double i1;             i1 = v1 / (r1 + r2 + r3);             Console.WriteLine(i1);             Console.Read();         }     }

problems we are starting simple, but since we are talking about real components like resistors that you might buy from Radio Shack or Fry's, there could be variations in values, the battery could vary between 2.50 volts (Ni-Cads) and 3.0 volts (Alkaline), plus the battery will vary with use as well.  How do we model this kind of variations.  How can we improve the input of the resistors, etc. 

If you want to learn more about F# and how to use it to do lists, etc. take a look at the other blogs such as Don Syme, Chris Smith and http://www.hubfs.com. This blog will be utilize for me to figure out how to use F# to solve engineering and scientific problems that non-computer science and computer science students both might be interested in.

In research, there is a need to have a set of ethics.  Software, as well as Electrical Engineers are ask to follow the ethics:

http://www.acm.org/about/code-of-ethics/#sect1 , the high level considerations are:

1. General Moral Imperatives

1.1 Contribute to society and human well-being.

1.2 Avoid harm to others.

1.3 Be honest and trustworthy.

1.4 Be fair and take action not to discriminate.

1.5 Honor property rights including copyrights and patent.

1.6 Give proper credit for intellectual property.

1.7 Respect the privacy of others

1.8 Honor Confidentiality

 

As you follow along on this blog, please keep in mind these ethics.

Hopefully you gave the code from Friday a try, Popfly should be used for that type of code, since there is that banner that advises people to not input their password, etc.  Now that you have run your tests, make sure to change your site or remove it.

Using Visual Studio 2008 Web Developer Express (let's call it Web Dev) I am able to connect to Popfly and use the Web Dev tool to connect with Popfly.  I am also able to share code directly with you.  However, for now, lets dig into the code.

If your Javascript is a little weak, and even professional software developers like Dan Waters sometimes have issues with javascript.  The best source that I know, that is also free, is the ECMASCRIPT Standard!  You might ask, ECMASCRIPT, what does that have to do with javascript?  The ECMA Standard is based on several originating technologies, the most well known being JavaScript (Netscape) and JScript (Microsoft).  Bottom line: ECMASCRIPT = javascript

Why is this important? ECMASCRIPT is the standard and programming standards are often good sources for figuring out how to make programs work.  This is true for C# and some other languages.  Other languages like Java (which is not the same as javascript, although the syntax is similar) and Visual Basic.NET are not programming languages that have a standard.  This means you have to search for assistance with companies like Sun (stock symbol: JAVA) or Microsoft (stock symbol: MSFT).  To get the ECMASCRIPT standard (which will help you with learning javascript) go to click here and then from the Adobe ribbon, click on the "save icon" , save this file to your harddrive, it is 188 pages, and worth the paper if you printed it out.  The ECMAScript standard though is weak on examples, for code examples you will need to go to other sites.

If you are using the Web Dev tool, you will notice that there are a series of "functions", in javascript this is a way to organize the programs flow in memory.  These functions are also correctly referred to as methods.  There are other software items that are called functions as well, for now we will work with the method kind of software items. 

What do we have in our example? A process to do the sign-in for the receiver and sender, both have to be in the other's contact list.  Also, we have now achieved the "nudge", we haven't figured out how to use it yet, but we a code example.  To work through a tutorial, which I can't get to work, let me know if you get it to work:

http://msdn.microsoft.com/en-us/library/cc298455.aspx, this example is pretty simple, and I recommend that you look at it.

This is the code that we use to create the sign-in control

This code: signin = new Microsoft.Live.Messenger.UI.SignInControl('signinframe', privUrl, chanUrl, 'en-US'); signin.add_authenticationCompleted(authenticationCompleted); Generates the control shown below:

To authenticate the user the following code is used:

_user = new Microsoft.Live.Messenger.User(e.get_identity());

_user.add_signInCompleted(signInCompleted);

_user.signIn(null);

Then to complete the sign-in:

if (e.get_resultCode() === Microsoft.Live.Messenger.SignInResultCode.success)
{
document.getElementById('userInfo').innerHTML = '<p>' + _user.get_address().get_address() + ' is now signed in.</p>';
}

 

However, as a person who is attempting to commercialize a research concept, you would what to understand how the code works, but you wouldn't do the code.  You would likely note down that you need a software designer who knows javascript and C#. 

Stay tuned for the next blog entry, we will take a look at the "nudge" and how we can use the Windows Live Messenger Library to call managed functions.  Since XNA is part of the managed code, we are getting closer to driving our Xbox controller with a nudge from Live Messenger.

It can be difficult to get started, and fortunately there is a web page that you can use to start experimenting with an accessible web page.  You will have to use the View Source to check out the code, on IE7 you would use the Page button and then select the "View Source" you will see the HTML.  It is a bunch of code, but if you are able to work with javascript and HTML, then this will be a great way to start experimenting with building your own IM graphical user interface (GUI).  Think about it, you could create a device that people who can't see or hear could use to communicate with people on the Internet!  All of this from an idea from Microsoft External Research.

To utilize the example code (this will just work with the Instant Messager, not the nudge), navigate to: http://wlmlhelloworld.mslivelabs.com/

You will need two Live IDs, one to send and one to receive.

Well, let's take a look what we need to do in the immediate future:

1. We have a place to experiment with the Live Instant Messager, you will need to have two IMs to be able to use this to start your experimentation.

2. We need to figure out where we can put our code, I think we can use http://www.popfly.com for your web page hosting, but you will need to download and install VS 2008 Visual Web Dev Express, and then install the Popfly explorer. 

3. Follow the instructions at the URL: http://msdn.microsoft.com/en-us/library/cc298455.aspx

Where we are going longer term:

1. We will have to investigate how XNA works, this will gives us easy access to the XBox controller through Windows.

2. Make sure to get an XBox controller, wired for Windows XP, and a cheap way to go for Vista which can use either wired or wireless.  But Wireless is very cool.

 

Finally, as we move into Labor Day weekend, since I don't have many readers, so please make sure to not drink and drive.  It is really true that buzz driving is drunk driving, and the fines for DUI are very high, in California the fines and court costs can reach $13,000 or more.  Have fun, take chances, but drinking and driving isn't risky it's stupid.  Of course if you live in a city with good public transportation like Boston, New York, Seattle or Philadelphia, lucky you.

 

Work on this project this weekend, we can hook up our code through the Visual Web Dev 2008 with the Popfly Explorer installed, and that is JUST COOL!

There have been a bunch of movies and even more stories where the bad guys or good guys are able to interact physically at a distance.  Usually there is violence involved, but what kind of fun can we have?  Well I am assuming that everyone who wants to take apart their Xbox controller to use it in our research have ordered it or are waiting till the weekend to get it from Game Stop or some place like that.  Research isn't any fun if we can't use the final product would it?  Also it wouldn't last long if there is no profit or benefit.

For now let's start talking about sensor touch and how you as a researcher could make it happen:

 

If you were an Intern or at your job, and your customer or manager asks you if it is possible to have the XBox Controller respond to a nudge from someone on IM, how would you approach this problem?

First, I would have to make some assumptions:

• The IM uses a standard that I can look at in a single location
• That the IM has an application programming interface (also known as API)
• That there is some way to connect to the XBox Controller

Then I would have look at the Sensor Touch, do I have to have two way capabilities to reach the goals of the researchers at Microsoft.  No, initially I can cut back a little and just have one touch through the "nudge" concept.  I don't have to go both ways.

Some questions for you:

1. Does Microsoft Instant Messenger have a standard?

2. Does the Microsoft Instant Messenger have an API?

3. Is there a way for us to use the XBox Controller?

Remember if you have an XP, you will need to get the WIRED controller to follow through with this research.

A final note: I have not prepared material ahead for this discussion, so as we move through the effort, you and I are exploring these technological concepts together.  I hope that you will have as much fun as I am having!

Well the Olympics continue and the Chinese are really showing off their abilities with a real leadership in Gold Medals.  And it is a good thing that Michael Phelps, a resident of California, showed up since it appears that he currently has won a large percentage of the US Gold Medals.  Gymnastics is about the ability of the performer to do specific actions, the outer edge of performance is difficult to measure.  With swimming, is it possible to estimate the edge of performance.  Simulations can be made from these estimates and strokes, clothing, etc. can be modified using the simulations.

Male swimmers are taller now, inches count in the swim events, Mark Spitz is less than 2 meters tall, Michael Phelps is much taller.  This gives Phelps an edge. 

What other factors would you use to simulate a swimmer?  Would your swimmer simulation have to be different for males versus females?  I would think so, male shoulders tend to be wider, this modifies the aerodynamic drag.  What other factors could vary the surface simulations for swimmers?

The image to the right, is from: http://tinyurl.com/gwu-seas.  Rajat Mittal, PhD, heads up the team of 10 researchers that make up the Flow Simulations and Analysis Group (FSAG) at George Washington University. The group's primary focus is analyzing the physics of complex flows using numerical simulations, at least it was in 2005. 

What kind of classes do you need to study in high school to be able to work on interesting problems like this in college and as an occupation?  Physics, AP Math, AP Computer Science oriented classes would be the ones you strive for.  If you have already left high school and think that this would be cool to do, but didn't prepare well enough, think about attending your community college and explore taking a series of math classes and programming classes to get you knowledgeable about what you need to know.  You can usually transfer these classes to a four year university.

How does this information relate to the wind/air tunnel research I talked about in my earlier posting?  Once the roughness of the material is determined, a team like the researchers at GWU would then be able to modify the surface of the swimming simulation to match the material's qualities.  The software would then be run and the output changed into a graphic like the one shown here.

How does Microsoft Research work with these types of simulations?  Microsoft Research has fostered the development of many of the approaches to graphics through improvements in the way that programmers work and utilize tools.  The programming tools that have come out of Microsoft Research, such as F# are leading edge approaches to simplification of programming large simulations.  Take a look at this URL for all of the projects that Microsoft Reseach has been working on: http://research.microsoft.com/research/default.aspx, all of them could be used in creating a swimming simulation.  After all wouldn't you like for your country or state to be able to knock out the Gold at the Olympics sometime in the future?  You can be a part of this by becoming smarter and more skilled at math and technology and then helping the swimmers to improve by creating useful simulations.  We can do this at any age, and use the public educational facilities to explore how to expand our knowledge about Math and Science, most countries support this type of exploration through subsidized classes.

Where else can you use this information?  In game design, graphics design, medicine, programming and engineering.

If you are interested in this type of material, please make sure you are studying online or in class, and write programs using the free tools from Microsoft. 

So to get started, Right now, click this URL and read about F#, download it, use it: http://research.microsoft.com/fsharp/fsharp.aspx?0sr=a this is an interesting tool, especially if you are a TI graphing calculator freak.