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rafd

211 karma · joined December 5, 2009

Experienced in ux, software engineering, customer development and the design process.

Partner at Bloom (bloomventures.io)

rafal.dittwald@gmail.com

[ my public key: https://keybase.io/rafd; my proof: https://keybase.io/rafd/sigs/98ypv3KPGqgEkA5oe2hL8zidAiibSOwtdWJ66rCr63I ]

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rafd··on Productivity brought by Clojure [slides]
If you're new to functional programming, I recently gave a talk on applying FP concepts at ClojureNorth:

https://youtu.be/vK1DazRK_a0

The main example I work through is in JavaScript so that Clojure's syntax doesn't get in the way (I love s-expressions, but they're not the point of the talk).

rafd··on My Parents Give Me $28k a Year
AFAIK, many countries do not tax gifts or have an estate tax (ex. Canada).
rafd··on A Year in Clojure
You can use spec to verify that "a value only contains items described in the spec". The core library doesn't make it easy, but spell-spec [1] contains some useful helpers.

[1] https://github.com/bhauman/spell-spec

rafd··on Argue with your customers
We do these sort of surveys a lot with our team. We found that users had a hard time coming up with the ranked list, but found making A vs B comparisons easy.

We slapped together a quick tool that lets you create pairwise surveys and then aggregates their results using the Schulze method (as if it were a preferential election).

We've released it for free: https://decidedly.so

rafd··on Zulip – Open-source, threading-based Slack alternative
That's the approach that we take in Braid chat: https://github.com/braid hat/braid

Works well, although some people are put off by the similarity to Twitter #sigh

rafd··on It’s always windy somewhere: Balancing renewable energy in Europe (2017)
On a simple network, the extra energy is "absorbed" by the remaining hardware components (think: wired getting hotter, etc.), eventually resulting in failure due to operating at higher voltages or currents than designed for.

Most electricity networks have a "system operator" whose job is to keep electricity generated track electricity consumed very closely. (An organization, with many automated systems, not a single person).

In practice, on a large network, the most noticeable side effect would be AC frequency fluctuations. In a severe case of imbalance, sensors/switches on the network would disconnect part of the network to protect the underlying equipment (probably causing blackouts, if not cascading blackouts).

The operator predicts demand and tells each of the many electricity generators how much electricity to generate. Some types of generation are easier to ramp-up o or throttle-down: for example, hydro and natural gas are very easy, while nuclear is not. Residential roof-based solar makes things complicated because it is now a new part of the system that is no longer under the operators control.

Some networks also have access to sinks of energy, the most common being pumped storage (usually in connection to a hydro facility), or even, industrial consumers who are willing to "ramp up" on demand.

On top of all this is usually a market layer (depending if the electricity generation is privatized or not). For example, in Ontario, the IESO (independent electricity system operator) asks for bids every 5 minutes from all the providers, and based on a modified dutch-auction, selects which providers are allowed to produce and sends them the corresponding instructions. Of course, taking into account various other technical requirements to decide who gets to power or not. In this kind of market, nuclear power, because it cannot throttle up or down, typically bids 0 or negative (because the actual price set is based on the last most expensive bid to get in). During some hours of the year, the market price of electricity is sometimes negative, because nuclear is the only bidder. In Ontario, the government phased out all coal production (yay, no more smog!), but... had to build a lot of new natural gas plants to be able to do the fast ramp-up/throttling the network requires on some days of the year. Most of the year, these plants sit idle.

rafd··on Ask HN: “If you build it, they will come” doesn't work. How do we market our app?
Talk to a few people that you would hope would be ideal users of your app -- ask them about their habits and media they consume to better identify potential channels that you could use to reach similar people.

Your earliest users are most likely to be ones who are already doing activities with regards to fashion -- perhaps check out /r/malefashionadvice on reddit and search for other online interest communities. I would bet there are instagram, pinterest and twitter communities around fashion.

Measure the success of your campaigns across channels, and the retention of users across each. You should decide if you plan to grow users by being 'viral' (fast growth, but user's don't stay long) or 'sticky' (slower growth, longer usage).

Any users you get and keep are likely to be the best advocates and already know similar users, so empower/incentivize them to invite the friends they think would be interested -- ideally in some way that is natural to the product. In the ideal case, the product is so good, they will immediately want to tell their friends who would be interested.

Finding an effective and repeatable marketing strategy can require as much thought and effort as the product itself.

rafd··on Lost Posture: Why Indigenous Cultures Don't Have Back Pain
FYI, even in the paleolithic era, if you lived past 15, the life expectancy was 54. [1]

Using average lifespan in your argument portrays a world where no-one lives to their 50s. When in actuality, most adults died in their 50s (but there was a very high level of child mortality which brings down the average).

[1] http://en.wikipedia.org/wiki/Life_expectancy

rafd··on Dateparser: Python parser for human readable dates
Huh! Just last week I did a survey of NLP Date Parsing libraries. If you're looking got something similar in other languages, see:

https://docs.google.com/spreadsheets/d/1dKt0R247B8Mx5sFXd7ht...

rafd··on Algorithm for Capturing Pokémon
We can get a more useful translation than "you need approximately 6 balls on average", here's how:

The process of capturing is a Bernoulli process [0]: each time you throw the ball, there is a P chance of catching it, and it is independent of subsequent throws.

Chance of catching, given 1 ball = P Chance of not-catching, give 1 ball = (1 - P) Chance of not-catching, given 6 balls = (1 - P)^6

For P = 17.5%, the chance that you don't catch your Mewtwo with 6 balls is 31% (which agrees with your observation that it often took more than 6 balls).

Let's try for 10 balls: (1-0.175)^10 = 0.15 (still a 15% chance of not catching it).

It's never certain! Even with 100 balls, there's a very slim chance you won't catch it.

[0] https://en.wikipedia.org/wiki/Bernoulli_process

rafd··on How to Cut the Poverty Rate in Half
I'm supportive of basic income, but slightly apprehensive of side effects. I think it would have to be rolled-in gradually so as not to shock the economic system.

Some other potential pros not mentioned in the article: - lowers barriers to entrepreneurship - allows parents to stay home and take care of young children - lowers barriers for re-education - could reduce costs of social services (through elimination of complex programs)

Side effects I'm curious about: - how will BI impact minimum wage? - how will BI impact entry level jobs? - how will BI impact cost of basic goods?

Also, the 'poverty line' should actually be location dependent because of the difference in food and rent costs in different places. Should BI be location dependent too?

rafd··on Startup Common Sense
On the one hand, entertainment products are difficult to capture by the current startup rhetoric because (1) the audience/market is broad, (2) the user doesn't have a problem (well, perhaps "boredom"), both of which put a damper on the customer development method.

Nonetheless, there's still a lot to apply. Identifying early adopter players and a channel to them, measuring retention and other analytics, iterating and releasing frequently, creating a viral loop -- these are all concepts that apply to game dev.

At some point, I think most games do try a "big launch" because ads and top 10 lists is how a majority of people find new games (even indie games now have the Humble Bundle as a consolidated channel). Another reason for big launches is the fake market dynamics of the app store: a one time boost when launching, and a positive feedback loop for downloads. But even with big launches, a lot of testing and tweaking is done internally (and it's standard practice on the app store to test the release in single markets, likes say Canada, because the app store stats are independent for each market)

rafd··on Ask HN: What are you working on?
Mobile educational language games: http://penyopal.com Our latest is a mystery game that you play by speaking: https://itunes.apple.com/ca/app/speak-mandarin-chinese-priva...

Also working on a startup board game modeled after Agricola.

rafd··on The Top Free-to-Play Monetization Tricks
I experimented with a pay-what-you-want model for a language learning game, and it was always hugely motivating to see players choose to pay 4.99 instead of 0.99. Financially, half of our income has come from players paying more than they need.

On behalf of non-coercive indie game devs, thank you!

rafd··on GeoGuessr: Guess the location from Google street view
Tip: cars drive on the left in Australia, so road signs and posts will be on the left.
rafd··on Log In or Create Account
It's not widespread because it adds extra steps for those who do remember their password (switch tab, wait for email, open email, click link), or for those who don't have their email client open (go to gmail.com, log in, open email, click link).

Marco's audience likely reads the magazine from within the appe (where the practice is keep the user logged in indefinitely) or they always have their email client open.

rafd··on In the Future Everything Will Be A Coffee Shop
It may be an issue of timing. Online shopping only took off in the last decade; the batch of consumers born after 1990 will have been exposed to internet shopping since childhood and will need much less convincing of buying anything online (than those who grew up used to buying things in stores).
rafd··on Show HN: QR Pixel encodes pixel art in QR codes.
It's difficult to draw white pixels with a (Macbook) touchpad. Allow for Ctrl+Click ?
rafd··on Mobiles for 65+. Need your input.
Thanks for the input. We'll put a lot of effort into the education aspect.

The "future 65+" is something we're thinking about; it's maybe too soon to go after them directly (existing services meet their needs pretty well), but it's part of our long term vision to deliver services to older people used to mobiles.

rafd··on Mobiles for 65+. Need your input.
Thanks for your insights.

A lot of the problem seems to be marketing and getting-started help and not just technology.

Based on our conversations with older people, we've been seeing a higher interest in tablets than other computer technology; the interaction model of tablets seems to match non-tech-savvy users' mental models much better. Direct manipulation (just touch it!) and not having to worry about files, folders, and the OS makes it much more approachable... but like you said, a demo is still needed to convince them. Have you or your friends had any experience with tablets?

We'll look into how far we can push voice-to-text, and we'll avoid 'boomer' henceforth. Thanks again.

rafd··on Portable sunshine: Earbuds that shine light into your ears
A 100W incandescent has a color temperature of about 3000 K, while the sun is 5700 K, so yes, it does appear more yellow. Because both incandescents and the sun are essentially black bodies, their color temperature is their actual temperature (the filament in an incandescent is about 3000 K).

Other light sources, such as white LEDs can produce 5700 K light, but their spectrum is actually much different from solar. They can get away with emulating 5700 K with only two or three wavelengths, while a black body emits approximately continuously throughout the wavelengths (this is due to the way correlated colour temperature is calculated; incandescents and the sun waste a lot of energy on non-visible infrared wavelenghts).

For electricity efficiency purposes, LEDs are great, because they don't waste electricity generating wavelengths we don't see (or ones that are cancelled out by other wavelengths). But for SAD, white light is likely not the requirement; our eyes have cells that have different sensory response based on wavelength -- apparent colour is an afterthought. Some of these cells are thought to affect SAD through melatonin inhibition, so the big question would be: what wavelengths are these cells most sensitive too, so we can optimize lights for them? Some cursory googling says that the jury is still out on that one.

tl;dr: colour temperature of light isn't what we should be optimizing for when dealing with SAD, because our eyes have spectrum sensors, not colour sensors. Be wary of marketing hype because you can likely get away with $1 lightbulbs, instead of $300 lamps.

rafd··on Portable sunshine: Earbuds that shine light into your ears
Off-the-shelf incandescents should do the job: the resulting spectrum matches daylight best compared to other sources (you get close to full spectrum black body radiation, like from the sun). It just becomes a question of supplying enough, but a 100W lamp (or two) near your work area may be enough to boost your mood. I'm no expert on SAD, but from the lighting physics side, "daylight" lamps sound like a scam.
rafd··on Introducing Asana: The Modern Way to Work Together
1. A task can belong to a number of projects. You could have projects for backlog, in progress, etc. and move a task between these (no drag/drop, but can be changed in the task panel)

2. Use tags instead, and use the tag filtering options.

rafd··on Introducing Asana: The Modern Way to Work Together
Tips:

Take advantage of keyboard shortcuts, it's what makes Asana feel so quick.

Asana lets you do things your own way (ie. it doesn't dictate a project management style), but a little structure is useful. Read their 'Best Practices:' http://help.asana.com/customer/portal/articles/84980-best-pr...

rafd··on I'm a serial over committer
I have the same problem: 'yes' is so much easier to say than 'no,' but the quantity of my projects is affecting the quality, and I don't like it.

Derek Sivers has a suggested approach for over-committers: "Hell yeah, or no." It's helped me cut down on my projects (and leaves me with more awesome things to work on, on average). Give it a read: http://sivers.org/hellyeah

rafd··on WebGL X-Wing
Same situation. Strange...
rafd··on Stypi (YC S11) Is Etherpad Reborn
Looks like they're using Ace underneath too. (http://ace.ajax.org/)
rafd··on How Dropbox sacrifices user privacy for cost savings
My take-away is this:

"What this means, is that from the comfort of their desks, law enforcement agencies or copyright trolls can upload contraband files to Dropbox, watch the amount of bandwidth consumed, and then obtain a court order if the amount of data transferred is smaller than the size of the file."

This, I think is significant, especially if Dropbox is advertising security, privacy and encryption. As the author mentions, the ToS are being updated to reflect the above possibility ("if Dropbox receives a warrant, it has the ability to remove its own encryption to provide data to law enforcement").

rafd··on Apple AirTunes private key extracted
Works great! Many thanks for the port.
rafd··on Canadians Just Became World's Biggest Internet Losers.
"Regulation of natural monopolies." Wikipedia goes into it better than I can: http://en.wikipedia.org/wiki/Natural_monopoly#Regulation
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