HNHacker News
TopNewBestAskShowJobs

jamesbkel

568 karma · joined September 5, 2009

Contact: [my_username] @gmail.com
submissionscomments
jamesbkel··on How to put a VC in the hot seat
I think the idea is that the investor is there to support a talented jockey (entrepreneur) against the turbulence of the horse (new business). Maybe this horse got outraced by another horse/jockey, but if the investor should have faith that the jockey can pick up the saddle and learn how to ride a new horse.

Agreed, not the best analogy... especially because as I understand a lot more is invested in horses than jockeys (in actual competitive horse racing). But, I think that's the point.

jamesbkel··on Stopping Screenlock Smudge Attacks On Android
Did you consider the idea of a combination (circular) lock?

I suppose it may be possible to decipher the stopping points, but if there's a final circle to confirm the code/cover them up, I could see that working.

edit: added "(circular)" to clarify

jamesbkel··on How to do deliberate practice
>Guitar hero has a mode that lets you practice pieces of a song. You can practice each segment to perfection, then play the whole song. This targeted practice should be a lot more effective and still obey the idea of what he's saying.

I guess maybe we understood him differently, because I thought that was the point he was getting at.

Regardless, I agree with the idea of "targeted practice" of each section. It's been awhile since I've done any serious piano playing, but my strategy for perfecting a piece was always to nail the final 4-8 bars 5x in a row. Then I would keep adding another 4-8 bars to the beginning of that and repeat the process until I could play the whole thing through.

I found working from the end to be much more effective than from the start. My guess is that it's less tedious since the new part is at the beginning, so if you're restarting after each mistake, you end up focusing on the new material instead of racing through the old boring material to get to the new stuff.

jamesbkel··on Poll: Should HN display comment scores?
There are already so many comments on this post that I hope this won't get lost in noise nor add to the noise. I did a quick search through the page and I don't think this idea has been addressed... apologies if it has.

I like not having having the score displayed, but I also like the option of seeing the score. My suggestion would be to keep scores off the main page but perhaps add an option to "click and see the score".

Not sure what the perfect solution would be, but to sum it up: scores should be accessible, but with traction.

jamesbkel··on Going Paper-Free for $220
>My desire is to shred junk mail without the indignity of having to open even the fattest faux-hand-addressed envelopes.

My strategy for this is to keep a bucket of that crap and shred every 6 months or so at a pro location. I've considered pulping the docs myself (mostly out of curiosity in the process), but from what I can tell, pragmatically it's more work than it is worth.

jamesbkel··on Going Paper-Free for $220
I've done similar, but just want to reiterate:

>if you're like me, ask them to shred it right then and there

jamesbkel··on 17% of Americans consider themselves Geeks
The main issue with this is there doesn't appear to be a definition of "geek" (aside from that Venn diagram). It's entirely based of respondent connotation of "geek".

In fact, the "Changing Definition of Geek" section makes this abundantly clear. It asks NOTHING about what the definition is. What it does ask is if it's positive/negative to be a geek and if it's a more common phenomena to be a geek now than in the past.

I think it would be better phrased: "Changing Connotation of Geek".

jamesbkel··on Leveraging the Chinese Landlord Principle
Had the exact same situation (Boston, 00's, basically fixed everything that didn't require trained electrician or plumber)... certainly didn't do me any good.
jamesbkel··on Leveraging the Chinese Landlord Principle
As someone who has rented from Chinese landlords at multiple locations as whose father owns property (not Chinese), I don't buy this.

Prompt/early payment aside, I have not experienced this and I've done a lot more apt maintenance than not call about toilets or lightbulbs. First of all, as mentioned in another comment, in both the case of my landlords and my father's business:

>they have full-time maintenance person anyway, so there's no feedback loop.

Unless you're a royal pain in the ass, I doubt they'll raise rent more than they do for anyone else. Otherwise, the delta convenience/hassle isn't enough for them notice or care to give you a deal.

edit: Anecdotally, if you happen to be renting a house from a small property owner who does not have a maintenance worker, then perhaps this may work (not me personally, but a friend). That said, you still probably want to find a place with a proper building manager.

jamesbkel··on Lady Gaga's $0.99 Album Download Overwhelms Amazon
Well, she had a lot of help from the N fans who purchased the album.
jamesbkel··on I refuse to tolerate assholes
http://en.wikipedia.org/wiki/Fundamental_attribution_error

I always try to give the benefit of the doubt. I can think of plenty of times where I only realize after the fact that I was distracted/in a bad mood and unduly acted rude towards someone.

jamesbkel··on Poll: Is linkedin only for consultants and the unemployed?
I was recently recruited while employed via LinkedIn, so it's not only for the unemployed. Additionally, it helped me land the job because I saw that the two owners and I had some mutual colleagues from the past. I'm almost certain that we wouldn't have discovered that without LinkedIn (or at least not during the course of the interview).
jamesbkel··on Site replicates effects of psychedelic drugs
Weird. I've never had any problem with visuals inducing nausea or motion sickness, but that (Deep Down, short) made me feel very unwell. Interesting part is the nausea only came on 5-10min later (I'm assuming it was that... aside from HN/Google News and a glass of water, that has been my only stimulus so far today).
jamesbkel··on How Little Sleep Can You Get Away With?
Did the advice apply to just your child or did it also include parental sleep habit advice?
jamesbkel··on Calculating your customers lifetime value (with code)
>what it allows you to do is to estimate the future duration -- saying that your average LTV is the 6 months of average revenue from your existing customers as the article suggests is incomplete, because the portion of customers who haven't lapsed will continue to provide revenue.

I'm almost certain we agree, just want to add two clarifying points for those interested:

+You probably want to try experimenting with different combinations of datasets for left-censored, right-censored and full lifetime cases. Or, at least segmenting that way when you perform the survival analysis (Haven't checked out noahnoahnoah's references yet, so they may mention this).

+Also, the other tricky thing is when it's a subscription service (3,6,12 month sort of thing). Main reason this introduces complications is that you need to account for a "unsubscribe signal" that may not sync well with the next prompt to renew. So rather than predict a survival likelihood at the unit of analysis (I assume monthly, maybe weekly) you need to generate a likelihood for the point in time when the user is prompted to renew (and again, you can also vary that to move it up before the real end of the subscription). It's not particularly hard to grasp at a general level, but it takes a lot of careful thinking of edge cases.*

*That description may be a little convoluted, to simplify: What happens when a 12mo subscription shows signs of leaving only 6mo in?

jamesbkel··on Calculating your customers lifetime value (with code)
Added email info to my username... I thought it was already there. Feel free to contact me.
jamesbkel··on Calculating your customers lifetime value (with code)
I've done some work on CLTV for one of the major online gaming services. Definitely agree with the segmentation by High/Med/Low as well as the deeper analytic segmentation.

One thing I like to tack onto the setup described is a survival analysis. I've done it mostly in SAS due to my clients, but it's just as easy (and free) in R. Essentially I'm using survival analysis to see what signs indicate someone who is likely to leave/downgrade/upgrade.

Can't really go into details, but essentially I was checking on: minutes played / # of friends who played the same games / freq of games purchased / freq of in-game purchases / purchase method (online vs. in-store giftcard) / plus a lot more. This was in order to predict likelihood of renewing at the next subscription term. Ostensibly this was to intervene and make an offer to retain a customer or squeeze more out of them. Can't say for sure what ultimately happened with the analysis and tools I delivered: I do know it helped someone score a new job.

I can't offer any of the original code (but I could write up some of the basic structure if there's some interest).

jamesbkel··on Programming error voided Green Card lottery results
For those interested, here's a nice intro that offers some insight into that question.

http://www.johndcook.com/Beautiful_Testing_ch10.pdf

jamesbkel··on Data Science & The Role of the Data Scientist
The 1790 census thing aside, I think what makes this such a nice infographic is that the creator didn't try to squeeze a bunch of numbers in there. Aside from the the pie chart (which I actually like since it is intentionally used to demonstrate misleading statistics) and a few other cases, it's primarily a written description.(I wish it would provide citations, but I'm satisfied with the accuracy of the information)

It didn't fall into the trap of trying to ornament charts by substituting icon for point on a chart or create 3D or otherwise exotic charts that are nearly impossible to interpret. Simply stuck to telling a story and that seems to work.

[edit: I should add. I definitely fall into the category of "Data Scientist". So while I have a lot of appreciation for quality visualization, I think in this case it was best to stick with a narrative and not try to incorporate anything quantitative into the visuals.]

jamesbkel··on Dear Record Labels: Focus on Buyers, Not Thieves
>1) The increased availability of digital music will lead to an increase in piracy

(not a criticism, I agree it's arguable)

I would suggest that the availability of pirated music is approaching a fairly good level of saturation. It also keeps pace with new releases and in most cases offers a much greater variety of older/niche music.

I always try to buy what I can, but sometime it's not an option.

jamesbkel··on Eureqa - detecting equations and hidden mathematical relationships in data
I played around with this about a year or so ago. It's a neat little program, but I'm not sure how practical it really is for fitting models in most cases. It could be useful for some very light exploratory work, but one would have to follow up with some more rigorous analysis.

That said, Andrew Gelman posted his thoughts on it awhile back.

http://www.stat.columbia.edu/~cook/movabletype/archives/2009... http://www.stat.columbia.edu/~cook/movabletype/archives/2009...

jamesbkel··on How I got into YC as a non-technical single founder
"Have a mindmap with the answers to all the questions they might ask."

Really loved this piece of advice and highly recommend. It's something I always do before an interview/presentation/important talk.

1) As Alex mentions, this is FAR more useful in the moment than a list of bullet points or the like.

2) Like a lot of note-taking, I find that the act of thinking about and creating the mindmap has advantages in and of itself. Often the act of carefully creating it means that I don't actually need to refer to it later. I personally find this with a lot of note taking. I spend a lot of time carefully taking notes - generally a bunch of notes, comments and citations connected by a bunch of lines in different colored inks, kind of a mix of "traditional" note taking and a bit of a mindmap. The time I spend really thinking about how to best present and relate all the ideas on a single page often leads to internalizing the content so well that I never really need the notes unless I'm coming back months later.

jamesbkel··on U.S. State Department adding intrusive questions for US passport apps
Exactly, from what I cant tell, this would make it easier to get a passport w/o a birth certificate since rather than deal with a traditional "bureaucratic investigation" (as BB calls it) you can fill this out in an afternoon.
jamesbkel··on Dropship — successor to torrents?
I've been doing the same, but on a very small scale. Mostly sending a funny episode of some show to a group of friends or occasionally sending a movie to my folks. I don't doubt that if I was mass distributing these files it would attract attention.

Also, wouldn't breaking the hash nullify one of the ostensible advantages of this method (the de-dupe of the stored files)? If the goal is solving global file distribution, making each copy of every originally-identical file unique - and therefore requiring n times the storage - isn't a viable solution.

jamesbkel··on Mac vs PC infographic
Would be nice if they gave actual percentages in place of the "x% more likely". Not particularly useful if I don't know the baseline.
jamesbkel··on Ask PG: How has voting habit/volume changed since being hidden?
This could become very confusing on new comments with several layers of response/conversation going on. That said, I like the spirit of the idea.
jamesbkel··on Company was hosting cardiac patient monitoring on EC2
I wish they offered some more detail on how important/life-threatening this is. Are we talking monitoring as in "detect signs of impending/occurring cardiac event and notify emergency services"? Or is this monitoring in a longitudinal sense, assisting physicians to look at trends in their patients? If it is the later case, is data stored on the device until it's uploaded, or is it simply lost if the connection fails?

Still, not really forgivable to be 100% AWS, but it's a very different story if this is primarily a recording device vs. a monitoring device.

jamesbkel··on Apple is not “recording your moves”
I've been playing around with the source today (planning to take a closer look at the file itself tomorrow). While there are definitely a fair amount of anomalie, even without removing the intended obfuscation in iPhoneTracker it still tells a good story. After adjusting the accuracy of the GPS grid and changing the animation to daily, it was easy to track where I had been.

It would probably be hard to track to any specific address (that's what I am looking into now) but by matching date with the coordinates it was trivial to see where I went for: 4th of July, my friends bachelor party and wedding, Halloween, Thanksgiving and New Year's Eve... among other events.

jamesbkel··on Why Leaves Really Fall Off Trees
As I understand, they are referring to the belief that wind was the mechanism by which the "dead" leaves fall off of the branches, not that wind in and off itself would blow leaves off of trees. According to the article, it appears that the trees actively dispose of the old leaves, rather than passive removal via wind.
jamesbkel··on Poll: Display points on comments?
I quickly scanned for another reference to this, but didn't see anything - pardon if a duplicate.

It seems that you can vote for both options. After I voted, the other choice still has the 'upvote arrow'. I didn't try to see if it worked since I don't want to vote for the other option.

Is this intended? I never noticed on any other polls, but maybe I just wasn't paying attention.

← PreviousPage 5 of 9Next →