December 14, 2014

ANU-ASTRO3x The Violent Universe

Tags: , ,

The series of introductory astronomy courses from ANU at EdX continues with ANU-ASTRO3x The Violent Universe, covering high-energy events and the remnants of stellar explosions. The structure of the course is exactly the same as Part 1 on Great Unsolved Mysteries and Part 2 on Exoplanets. It is a 9-week course with about an hour per week of video lectures. There are also mini-tests and a homework assignment each week with a final exam. The exam is based on a “mystery” universe nullifying real-world knowledge and forcing the student to fall back on basic principles. The lectures are almost a conversational back-and-forth between the presenters Paul Francis and Brian Schmidt (with pictures and notes appearing projected behind them).

The course starts by looking at Sirius B. In the 1800’s it was determined that Sirius (the brightest star in the sky) was wobbling and must be orbiting another small body with a mass about the same of our Sun. This led to the discovery of white dwarf stars. These stars are about as heavy as the Sun, but only as large as the Earth. They also have a tendency to accrete disks of matter from any larger and less dense companions. This in turn can result in dwarf novae, where instability in the accretion disc causes a burst of energy; and, classical novae when hydrogen from the disc builds up on the white dwarf, eventually exploding. White dwarves can also cause the much large type Ia supernovae, where enough material accretes on the white dwarf to start carbon fusion and a runaway thermonuclear explosion. Other types of supernovae result from large stars (much larger than our Sun) reaching the end of their life and exploding after their core collapses. The remnant of such an event is a neutron star or maybe even a black hole.

The difficulty level of these courses only seems to decrease. It is now so easy I didn’t feel there was any value in spending the time to complete the assessments – just watching the videos seemed enough. The lectures still run through the basic maths at the algebraic level (no calculus), but the assignment is often a multiple choice question or much simpler maths question.

Entertaining and informative videos, not sure about the value of the assessment and resulting certification.

December 7, 2014

Game Reviews


In a burst of enthusiasm for games right before the last Steam Summer Sale (in June) I played a number of games in my library in an attempt to increase the played game percentage. Now 15% of my Steam library has been played (up from 10% beforehand). It would take a lot of time to clear that backlog! However, in a fit of perversity, most of the games I played in that burst were games I was unlikely to enjoy – so it didn’t take too long to decide to abandon them. Anyway, from best to worst, here are my short reviews from those games.

As before my ranking system falls into 3 broad categories: games I have finished or want to finish; games I played for a while, but may or may not play again; and, games I deleted from my spacious hard drive after an hour or so.

Mark of the Ninja is stylish 2D side-scroller action game with a stealth mechanic. You are a ninja investigating an attack upon your dojo. Thus you creep and swing your way through various buildings avoiding, or if necessary, quietly disposing of the guards. Guards can detect you via line of sight (so disabling lights, or going through the ducting is very handy) or noise. It is very easy to see what is happening and how your actions affect the guards. Very impressive UI design. Puzzles seem to be logical and combat is dangerous and to be avoided. The game is also beautiful, done in a cartoonish style – mainly in black with occasional flashes of bright colour. I intend to complete this game.

Dust: An Elysian tale is another pretty hand drawn 2D sidescroller action game, but instead of stealth the player just fights their way through the huge mass of enemies that assault them. There is a semblance of story, as the player struggles to recover their memory as monsters roam the countryside, but it seems fairly unnecessary. Basically it is fight, fight, fight. And the fighting is surprisingly fun. The player’s avatar reacts nicely to commands and feels powerful, with the special actions being particularly destructive in their devastating effects. My only concern is how quickly I progressed through the game. While entertaining, none of the battles were challenging – every fight was won with ease, and I’m not a great gamer. I stopped about half way through, and am not sure whether I will return.

Read the rest of this entry

November 23, 2014

Concealed Intent Update


Have you heard of the sunken cost fallacy? It is where people base their decisions on historical costs rather than future benefits. It is logically incorrect as events or costs incurred previously are in the past and should not affect people’s next decisions. However, it is very common.

Right now, I may be falling foul of this fallacy, but I don’t care! I must finish Concealed Intent!

Work on the game is continuing. It has been just over 2 years of my life now, and I think it is finally nearing completion. To that end, I have set a deadline of the beginning of March next year. That is not a random date, it is when the Game Developer’s Conference is held, which I will attend. I still think that is an achievable date. Although when I look at the the screenshot from last week (above) I still see so many things that have yet to be done. It appears to be an ever expanding list of todo items, as finishing one task presents many previously unconsidered tasks! I have heard it said that no game is finished – they are all just abandoned when “good enough”!

Soon I will be ready for another round of testing. So if you have previously said you are interested, I hope to contact you, probably in the new year for some early beta testing (I’ll put you on the Concealed Intent mailing list).

As obscurity seems to be the greatest enemy of the indie game developer, I have also begun to get the good word out on Concealed Intent. There is a blog at Gamasutra and soon other places too. Plus many social media accounts as detailed below. If you have any other ideas where I should promote the game, please let me know!

Concealed Intent Contact Details:

November 11, 2014



Reading stories about the British government beginning to pay down some of its World War I debts reminded me of my old job. I know a few people who are probably quite happy this is finally happening. This is not because they believe the UK has too much debt and needs to pay it off, but because it will make their jobs just a little easier, as it would have for me five years ago.

The background is that the UK raised a very large amount of debt to pay for fighting WWI. Soon after the war was finished the debt was refinanced into “consols” (along with some older bonds). These consols are perpetual bonds (we used to call them “perps”) – a very rare form of debt where the original debt need never be paid back (it is the government’s choice). Instead they just pay interest for ever (“in perpetuality”), unlike normal government bonds which mature and the principal repaid after some set period of time (commonly 5, 10, or 20 years). Thanks to inflation and a low rate of interest, it has never been in the financial interest of the UK government to cancel their consols (and thus repay the principal) – it is very cheap debt. Presumably right now is the unusual occasion when interest rates are so low that paying off the consols makes sense (at least I hope so). Of course it is also good publicity for a government strongly associated with austerity to pay off such symbolic long-term debts.

These consols and other perps comprise a vanishingly small fraction of UK debt and an even smaller proportion of traded debt (as the debt holders don’t tend to sell them very often). Someone working in UK and European bonds could pretend they don’t exist, and 99% of the time this would not be a problem. Then there is the other 1% of the time. Perpetual bonds have a different set of calculations for working out their price and other maturity dependent values. When writing code for pricing and trading bonds, testing should include perps to check they are correctly handled. In the fast paced world of front-office IT, this extra checking is sometimes forgotten. Normally nothing untoward happened as a result. However, errors did occur, normally days after the code was released (as it takes that long for a perp transaction to occur). I was lucky enough never to have that particular problem while working in a bank, although I did something similar once with uncommon yield-quoted bonds and felt like an idiot for forgetting such instruments existed (but it never happened again – I always tested with them after that).

So congratulations to the technical people writing fixed income pricing and trading systems. With the consols gone there is failure point removed. Hopefully soon your code will be simpler and all the if (isPerp) { ... blocks can be deleted.

November 1, 2014



Playing Eve has really made me think about the financials of online gaming with regards to digital goods. Like most online games, Eve bans real money trading (RMT). That is, buy or selling of in-game items for real-world money is forbidden. The exception being that it is ok to buy PLEX (game time vouchers that can be used in-game) from Eve or approved affiliates. A non-approved reseller, Somer, was recently shutdown.

This intrigues me. It seems to me that real-world trading would make players more engaged in a game. Second Life made a virtue of RMT and didn’t seem to suffer ill affects from the policy (their problems seem to originate in being over-hyped). So why do nearly all MMOs ban the practice? Is it because the companies want to control the market for selling these goods themselves? Maybe partially, but having a resale value only increases the possible primary sale price and increases demand. I’m not sure this is the main reason. Perhaps there are legal issues? I’m no lawyer, so this is possible. An online investigation discovered another possible reason – avoiding professionals.

If it is possible to earn money from playing the game (through RMT), then some people may find that that playing intensively results in enough money to live (or thrive). This is definitely possible, even although the activity is banned, gold farming in many games is profitable enough to make a living. The now closed Diablo 3 auction house suffered a similar problem. Some players acquired huge amount of loot and then sold it so cheaply that other players without the same interest in grinding would just buy it from them.

The problem seems to originate in the standard mechanics of such games. In-game rewards come from endlessly repeatable activities – usually as loot. Why get rewards for killing creatures? Why do those creatures respawn over and over again? Why do the creatures have all this great stuff on them (instead of leaving it at home) and why don’t they use it? In some games, why can players carry so much? It is because these loot-based rewards promote people playing – perform an action, get a reward. Companies that produce these games want to discourage professionalism so other players have a chance to partake in this gamification. Introducing scarcity by limiting the spawning of enemies would make the situation worse as this would make the resulting rewards even more valuable.

To have RMT and reduce professionalism, these games would need to stop repetition of gameplay as the basis for rewards – like Minecraft. Or, stop repetition of the core gameplay, by perhaps time-limiting players (but then a pro might have many characters or a whole team). Or, co-opt the professionals’ activities into creating content for other players. This last options seems the best, but is it possible or even desirable? Eve manages it a little with its null sec sovereignity and corporations, but at the expense of large-scale player-vs-player gameplay (which brings its own problems). I suspect the far easier option is to just ban RMT.