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xjtian

19 karma · joined March 11, 2013

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xjtian··on Candy Crush is NP-hard
Direct link to PDF: http://arxiv.org/pdf/1403.1911v1.pdf
xjtian··on University of Maryland Data Breach
I'm a student at UMD right now, and pretty frustrated to find out about this. IMO, the university should do a lot more than just providing a year's worth of credit monitoring, because once that year is up and people forget/choose not/can't afford to renew, chances are 90% of those records are going to be easy pickings for identity thieves.

300,000 SSN's, names, and DoB's is one helluva haul though. At least no academic records were compromised, god forbid anybody takes a look at my grades before making off with my identity! \s

xjtian··on OS X Mavericks kernel_task eating 100% CPU
I've been running into this problem with my 2013 MBA. It happens on wake, and the only that fixes it is a reboot. I'm getting pretty fed up with the issue since it's tanking my battery life and there seems like nothing I can do to fix it permanently.
xjtian··on Plain English explanation of Big O
The "too much time has passed" bound on each iteration guarantees that you don't end up running an iteration forever, and makes the algorithm O(2^N), since the number of programs up to N bits long is 2^(N+1) - 1.
xjtian··on CrossFit's Dirty Little Secret
The vast majority of Crossfitters are not at a level of physical fitness and mental toughness that would put them at risk of rhabdo after a WOD. They'd throw in the towel long before "meeting Uncle Rhabdo" under most normal circumstances.

However, certain external factors can affect the risk - high humidity, heat, improper hydration, and poor nutrition can significantly increase the chance of catching rhabdo from a workout. It sounds like the subject of this post got caught up in the competitiveness of the workout, turned a deaf ear to what her body was telling her that day, and paid the price for it. It's a mistake that many inexperienced athletes make when thrust into a competitive setting, and most of the time only ends with "meeting Pukey" or some really bad DOMS the next morning, but the specifics of this circumstance (pushup-overhead couplet sounds like a stupidly dangerous WOD, plus a "warm Texas evening") lead to a significantly worse outcome.

xjtian··on Algorithms, Part I: Kevin Wayne and Robert Sedgewick
I found the video lectures for this course extraordinarily boring compared to the Stanford algorithms courses taught by Roughgarden. Sedgewick is a brilliant computer scientist, but those videos really put me to sleep.

Both classes are still solid offerings from Coursera, but having gone through both levels of both, I'd recommend the Stanford ones first.

Also, I don't know if this has changed, but the programming assignments required a custom Java installation provided by Princeton with a bunch of extra packages specifically for the course. I found that a little weird compared to the Stanford class's approach of just giving you an input file and verifying the output provide (ala a coding competition).

xjtian··on Google+ spamming people every 2 weeks to put up a profile photo
For the iOS gmail app you can choose to be notified for all new mail or "primary" only. I'm not sure about using a built-in client like the Mail app though.
xjtian··on Write Your Notes In Markdown, Open Source Them On GitHub
I've been taking notes in LaTeX and keeping them in source control recently. I still prefer to take notes during lectures by hand, but usually within a week of a lecture I'll transcribe them into TeX. It takes a lot of extra time, but taking notes twice like this helps me remember the material better so I don't have to cram before exams.

All the notes I've taken so far are at https://github.com/xjtian/class_notes. There's some cleanup/updating I've been meaning to do for a while but I haven't gotten around to it (summer).

xjtian··on [dead]
It's a sad situation, and the officer never should have fired his sidearm at the dog, but to be fair to them, they didn't just shoot the dog with no provocation - the dog lunges 2 or 3 times at the officers with clear aggressive intent before it's shot. There are a million different things these officers could have done a lot better in this situation, like not arresting the videographer in the first place, or using pepper spray or some other nonlethal means to subdue the animal, but it wasn't like the officer walked up to the dog and shot it execution-style.

The dog's last lunge toward the officer who killed it was very fast and aggressive, and the officer had just a split second to react. He probably just reacted on a fight-or-flight instinct, and unfortunately, in this instance, it ended with lethal force.

If I was in the same situation at that split second, I might have done the same thing. I was once chased and attacked by an aggressive dog before, and I rank it as one of the most terrifying experiences in my life. Being attacked by an animal with clear intent to harm or even kill you is just so primally scary that there's no way to think and react rationally - you just do whatever you can to get away and survive.

It's a pretty crappy situation all around, and I feel terrible for the owner of the dog. I still blame the officers for initiating the situation, but I do understand why the officer reacted the way he did.

xjtian··on Buying the new MacBook Air
MBA's really are the best ultrabooks money can buy right now. I'd say the X1 Carbon from Lenovo comes close, except if you want comparable specs you'll have to shell out a lot more cash, and that's pretty much the same story with all other ultrabooks out there right now - if you want comparable form factor and hardware to the MBA, it's going to cost a lot more.
xjtian··on GeoGuessr: Guess the location from Google street view
I allowed myself to Google everything and got 23,100 points. I got 3 out of the 5 locations basically exactly correct. The challenge is here: http://www.geoguessr.com/?s=eyJ0b3RhbFBvaW50cyI6MjMxNjgsInZl...
xjtian··on A Better To-Do List: The 1-3-5 Rule
Sometimes it's not so straightforward to split up large into many small tasks. A lot of the time these steps will depend on other unpredictable factors, which leads to a lot of backtracking and adjusting my to-do list down the road when I should be working.

I'm a fan of iteratively processing my projects, deciding just the next one or two steps every time I process my tasks. I find that if I let my to-do lists balloon in size, I have less motivation to actually clear it out. But that's just me. In the end it's all about making the right decision based on how you know your brain works.

xjtian··on A Better To-Do List: The 1-3-5 Rule
I use an app called pocket informant on my phone. It's a nice all-in-one organizer that supports GTD-style tasks and syncs with my Google calendar.
xjtian··on A Better To-Do List: The 1-3-5 Rule
I think the rigidity of this system is its biggest drawback, as is the case with most productivity systems. For example, if I have two large projects that I need to get done and I only write down one, the other is going to keep nagging at me in the back of my head while I'm working and distract my focus. If I write both of them down, then I've deviated from the system, which in my experience means that by the end of the week, it'll just devolve into a vanilla to-do list grouped by the 'size' of tasks.

That's mainly why I switched to GTD for all of my to-do lists and projects. Because my inbox holds literally every task or to-do item that pops into my head during the day, I never have that distracting "am I forgetting something?" feeling during the day. I can process and sort my inbox whenever I have free time, and the flexibility in deciding which tasks should be made into projects, next actions, etc... means that the system always fits my schedule no matter how unpredictable or crazy it is, instead of me having to fit my schedule into the system.