# tianjara.net | Andrew Harvey's Blog

### Entries from December 2008.

24th December 2008

In the past month or two I've been watching and listening some of Lawrence Lessig's presentations and I've got his books on my reading list. I could do a lot of blogging on those topics but I wanted to focus on one particular thing. As I was reading Code v2 it lead me to think about a copyright issue that is close to me. It deals with the fact that the Board of Studies NSW, a government organisation copyrights (with a very restrictive license) its syllabi. These syllabi document what students should learn as part of their secondary state education HSC courses. These syllabi are material that students use as part of their study.

For the purposes of review here is the license that the syllabi are provided under,

"© 2002 Copyright Board of Studies NSW for and on behalf of the Crown in right of the State of New South Wales. This document contains Material prepared by the Board of Studies NSW for and on behalf of the State of New South Wales. The Material is protected by Crown copyright. All rights reserved. No part of the Material may be reproduced in Australia or in any other country by any process, electronic or otherwise, in any material form or transmitted to any other person or stored electronically in any form without the prior written permission of the Board of Studies NSW, except as permitted by the Copyright Act 1968. School students in NSW and teachers in schools in NSW may copy reasonable portions of the Material for the purposes of bona fide research or study. Teachers in schools in NSW may make multiple copies, where appropriate, of sections of the HSC papers for classroom use under the provisions of the school's Copyright Agency Limited (CAL) licence. When you access the Material you agree:
• to use the Material for information purposes only
• to reproduce a single copy for personal bona fide study use only and not to reproduce any major extract or the entire Material without the prior permission of the Board of Studies NSW
• to acknowledge that the Material is provided by the Board of Studies NSW
• not to make any charge for providing the Material or any part of the Material to another person or in any way make commercial use of the Material without the prior written consent of the Board of Studies NSW and payment of the appropriate copyright fee
• not to modify the Material or any part of the Material without the express prior written permission of the Board of Studies NSW."
Board of Studies NSW

In my opinion this is absurd! This is depriving students access of material that they require for their studies. This is not a private education institution, this is a government public education system. Students need to know what to study, this document tells students what to study, and as this document is not distributed to students (as in students are not provided a hard copy) the only way they can access it is to copy it, but apparently this is illegal!

The above license does give some rights to school students in NSW ("School students in NSW and teachers in schools in NSW may copy reasonable portions of the Material for the purposes of bona fide research or study."), but why only school students in NSW, what about publishers who are providing material to help students in their studies (for example an annotated copy)? Also why limit the amount students can copy to "reasonable portions"? So basically students cannot make whole copies of this document to aid in their studies!

Also why can't anyone remix the document adding their own annotations or commentary and then publish this? And why only for "personal" use? What if I want to provide a remixed copy to anyone who wants it? If the Board is worried that someone may change the document then republish it and someone mistakes this as an official version, then they should not worry. People are not stupid they know that if they want to ensure the reliability of the document they will go to the source. This is not a valid reason for refusing copying of the document.

These documents should be licensed more freely. They should be in-near public domain allowing anyone to do whatever they want with it. I say "near public domain" because I can understand the Board wanting attribution. But apart from that I don't see any other legal constraint that needs to be placed on these documents. Board of Studies, please consider a license such as the Creative Commons Attribution-Share Alike 2.5 Australia License.

I welcome comments on this matter.

12th December 2008

In Terence Tao's latest post he poses three questions. Here are my solutions.

Suppose you are trying to get from one end A of a terminal to the other end B.  (For simplicity, assume the terminal is a one-dimensional line segment.)  Some portions of the terminal have moving walkways (in both directions); other portions do not.  Your walking speed is a constant v, but while on a walkway, it is boosted by the speed u of the walkway for a net speed of v+u.  (Obviously, one would only take those walkway that are going in the direction one wishes to travel in.)  Your objective is to get from A to B in the shortest time possible.
1. Suppose you need to pause for some period of time, say to tie your shoe.  Is it more efficient to do so while on a walkway, or off the walkway?  Assume the period of time required is the same in both cases.
2. Suppose you have a limited amount of energy available to run and increase your speed to a higher quantity v' (or v'+u, if you are on a walkway).  Is it more efficient to run while on a walkway, or off the walkway?  Assume that the energy expenditure is the same in both cases.
3. Do the answers to the above questions change if one takes into account the effects of special relativity?  (This is of course an academic question rather than a practical one.)
Source: Terence Tao, http://terrytao.wordpress.com/2008/12/09/an-airport-inspired-puzzle/

## Q1.

After just thinking about it without any mathematics I was not to sure so I used a mathematical approach. The first thing I did was to draw a diagram,

Admittedly, I did simplify the problem in my diagram, however I am confident that this will not affect the final answer. (How do I prove this? I don't know.) Along with this diagram I also had to define some things in terms of variables.

As shown in the diagram, A is the starting point, B is the ending point, C is an arbitrary point in between which separates the escalator section from the non-escalator sections.

Let, t = time it takes to tie shoe lace v = walking speed u = escalator speed $T_{ac}$ = time it takes to get from A to C $T_{cb}$ = time it takes to get from C to B $T_{ab}$ = time it takes to get from A to B

We also know, $speed = \frac {distance}{time}$.

Now lets consider two scenarios. Scenario A, the person ties their shoe lace in the non-escalator section. Scenario B, the person ties their shoe lace in the escalator section.

### Scenario A:

$T_{ac}=T_{ab}+T_{bc}=\left (t+\frac{d_1}{v}\right )+\left (\frac{d_2}{v+u}\right )$

### Scenario B:

$T_{ac}=T_{ab} + T_{bc}=\left ( \frac{d_1}{v}\right )+T_{bc}$ Now let $d_3 = \mbox{distance traveled in} d_2 \mbox{while the person is tieing their shoe lace.}\\ \ =vt$ $\therefore \mbox{walking on escalator time for time } t_2 = \frac {d_2 - vt}{v+u}$

I shall now make some reasonable assumptions (also formalising things a bit more),

All variables are real, and we shall assume that the person has time to tie their shoe lace while on the escalator. I.e. $t \le \frac{d_2}{u}$

I shall denote $T_A$ to be $T_{ac}$ from scenario A and $T_B$ to be $T_{ac}$ from scenario B. Now to see which is larger $T_A$ or $T_B$ we can examine the sign of $T_A - T_B$. If it is positive then $T_A > T_B$, if it is negative then $T_A < T_B$.

By some algebra $T_A - T_B = \frac{vt}{v+u}$ and as $v, u, t > 0$,  $T_A - T_B > 0$. Hence $T_B < T_A$. Therefore it would be more efficient pause for a moment while on an escalator walkway.\

## Q2.

I will take a similar approach for Q2, examining the two cases and then comparing the resultant time.

(I'll re-edit the post when I get around to working out the solution)

Tags: mathematics.
12th December 2008

I just checked the junk mail box of my hotmail email account, inside I find an email with subject "Imagine Cup - Thank you for registering.‏" from "admin@imaginecup.com". So I go to imaginecup.com and it turns out that the web site comes under the Microsoft umbrella, that same Microsoft that Hotmail falls under. I find it quite odd that Microsoft flags its own email as spam. I should note that I did acutally register for this email, so it was not quite spam. Althought I do realise (although I'm just guessing) that the spam tag that this email was assigned was probably automatically generated from other users marking it as spam.

No tags
7th December 2008

As reported here and here the government will reportedly be issuing NSW years 9-12 students will a free laptop each. If this is true and if the government goes ahead with it there are some issues I think need addressing. As reported in The Age, "Next year NSW would begin rolling out lightweight, three-quarter sized laptops to the 197,000 students in years 9 to 12 with a lightweight." A lot of the issues depend if students will leave the laptops at school or home, or take them to and from every day. However as reported by The Age, Ms Verity Firth the NSW Minister for Education and Training said "That means the kids can bring their laptop in, open it up at their desk and just use it" So lets assume that either students will have to take them to and from school everyday, or can by choice. The first problem I see is if every 9-12 kid in the state has a high chance of having a laptop in their bag then street crime may rise and students may be mugged for their laptop. Unfortunately streets are not yet safe enough. Ms Firth reportedly also said, "It will be connected to the Department of Education network. As it is security coded there will be no impetus to steal one of these, because you won't be able to get access to the network." I can't see how this would technically work, and I very much doubt that it would work. Short of being stolen, what is stopping kids selling the laptop for cash?

Another issue is (more so for year 9-10 rather than 11-12) but I think a lot of students will not look after their laptop. Have you seen a group of year 9 kids, some throw bags around, others get tread on, and on a crammed school bus or crammed corridor some guy will just push everyone like sardines in between a rugby union scrum. Books inside bags can survive this, but laptops stand no chance. Schools will also have to up their security (although this is a good thing) as in the past and probably still now you would be refused to enter a certain classroom unless you left your bag outside in the corridor open to thefts.

They are some of the major concerns I have, but also students will just end up playing games, watching movies, instant messaging, emailing, surfing the web (although not so much due to the locked down nature of the DET provided internet) instead of doing school work or listening to the teachers, though I'm not sure if these things are good or bad. Because these technologies could also be using in a more relevant learning related way. For instance what would be better for the student, reading up the topic on Wikipedia instead of not making sense what the teacher is saying; instant messaging a friend about something the teacher just said instead of talking out loud and disrupting the teacher. I think we should not move so quickly to say this kind of behaviour should be condoned or discouraged rather more discussion about it should occur. This is a whole different argument and whole different matter to what I was originally trying to explore in this post, but although the technology is changing these kinds of things have been happening in the past and will continue to happen in the future. The thing that does change when you introduce technology into the classroom is that instead of the teacher being able to see if you are reading a maths textbook or science fiction novel, the teacher can no longer tell what you are doing on your laptop. These are some of the benefits of laptops in the classroom, however I think more discussion is needed.

Additionally, what will  happen when specific software is needed for a particular lesson. For example AutoCAD for a technical drawing class. You can't remove the classroom PCs yet as they would be the ones with the software installed and licensed on. There may be ways around this though.

The Age reported that "The roll out would cost $2,245 per student". Putting aside network infrastructure$2245 does sound a little too much for a mini-laptop. Currently you can get a HP DV5-1004AX (FK680PA) (CPU: AMD X2 Duo Core 2.0Ghz, RAM: 2GB DDR2, HDD: 320GB SATA, Graphic: ATI Mobile 3450 VGA dedicated 256MB, Screen: 15.4” WXGA (1280 x 800), DVD Burner Lightscribe, Card Reader, WiFi 802.11N, Gigabit LAN...) for $999, minus the cost of Microsoft Vista if you opt for a free OS like Linux. At that is not bulk buying. The$2245 per student may have changed, or may include other costs that may explain a bit more, but it is way too much for just the laptop.

Lastly the internet available at DET schools is mostly useless due to over-blocking sites on the internet. So the use of the laptops would be severely limited by this, although that is another matter entirely.

UPDATE: So it seems I have finally leant something. I should have gone straight to the source, the Premier's Media Release. After reading it I see how the media can change views. For instance "The computers will cost around $500 per unit with running costs bringing the cost per student to$2245.", which is not how I interpreted the media outlets stories.

Tags: education, politics.