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Sean Leather
Worked at Anue Systems
Attends Utrecht University
Lives in Pretoria, South Africa
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Sean Leather

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Cool Chattanooga history.
Harriet Whiteside was one of the richest people in Chattanooga, and the legacy of her controversial railway still shapes Lookout Mountain to this day.
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Sean Leather

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The story of our (somewhat powerless) lives in South Africa: planning our time around blackout schedules.
Sub-Saharan Africa’s power generating capacity amounts to less than South Korea’s, and a quarter of it is unproductive at any given moment because of the continent’s aging infrastructure.
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Sean Leather

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Interesting concept and description of a Prelude substitute
subhask - Type safe interface for working in subcategories of Hask
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Jim Stuttard's profile photo
 
+Charles Wells +John Baez Mike's deep learning library project is based on the Rosetta paper so I bet he'd like to know if you have any useful comments on his formulations. He's at Riverside.
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Sean Leather

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Alright, I'm annoyed.

Telkom [1] — probably the largest telephone and Internet provider in South Africa and the only ADSL choice we have for our location — is inserting HTML into websites that I visit.

[1] https://en.wikipedia.org/wiki/Telkom_(South_Africa)

First, see the screenshot here. The image is http://images.telkomsa.net/ibn/90_s.png .

Second, consider the following HTML found in the same website.

This is the <div> for the overlay shown:

<div id="n_882998037" style="position: fixed; z-index: 9999999999; bottom: 0px; right: 0px;"><img src="http://images.telkomsa.net/ibn/90_s.png" style="width: 250px; height: auto; margin: 20px; padding: 15px; overflow: hidden; border-radius: 10px; box-shadow: rgb(0, 0, 0) 3px 3px 20px 2px; background: none 0% 0% repeat scroll white;"><a href="#" style="font-family: 'Arial Black'; font-weight: bold; font-size: 20px; text-decoration-line: none; position: fixed; right: 20px; margin-right: 5px; margin-top: 20px; color: rgb(128, 128, 128);">×</a></div>

This looks like something used to record the URL of the site holding the inserted HTML (URL elided):

<img src="http://196.25.211.41/ev/882998037.png?0=50fc073bb429a4eb303a6420235e9381&amp;1=delivered&amp;2=<url-visited>" style="display: none;">

I believe these indicate the status of the overlay (“displayed” or “autoclosed”):

<img src="http://196.25.211.41/ev/882998037.png?0=50fc073bb429a4eb303a6420235e9381&amp;1=displayed&amp;2=" style="display: none;">

<img src="http://196.25.211.41/ev/882998037.png?0=50fc073bb429a4eb303a6420235e9381&amp;1=autoclosed&amp;2=" style="display: none;">

Third, consider the following script:

http://196.25.211.41/n/50fc073bb429a4eb303a6420235e9381.js?q=%2FP0p7VooS5OltsQRJup5Kg%3D%3D%7C1435050755%7Ce718e8319f2883d1950358cbdf305f4f&url=http%3A%2F%2Fwww.google-analytics.com%2Fanalytics.js

I didn't find this in the rendering of the site, but I did see it in the Sources tab of Chrome's debugger. It appears to include the URL of a script in the page. Here is another for http://www.sabc.co.za/wps/portal/SABC/SABCHOME :

http://196.25.211.41/n/50fc073bb429a4eb303a6420235e9381.js?q=EScVDZ8A9f7Qxd3n17pxzQ%3D%3D%7C1435052196%7C2b7eb01a412a27c40f8b33260fb05520&url=http%3A%2F%2Fwww.sabc.co.za%2Fwps%2Fmenu%2Fmenu_service.js

Finally, how do I know 196.25.211.41 is from Telkom? For one thing, it is almost unheard of to find links to the same IP address on multiple websites from different domains. But, more concretely, sites such as the following indicate Telkom SA as the owner:

http://www.dnsstuff.com/tools#ipInformation|type=ipv4&&value=196.25.211.41
http://whois.urih.com/record/196.25.211.41/

See also: https://www.google.com/search?q=196.25.211.41

To conclude, I just discovered this because Telkom started showing me these overlays, but I don't know how long they've been doing this. After visiting several sites, I've found that they don't insert the code everywhere, but I don't know which sites do or do not get this treatment.

There are ways to get around this, but the more important question for me is: should this be allowed? I think it should be illegal. It's a violation of my rights as a consumer of the Internet. I should know, at the very least, that the data I request from a website will be transferred to me without mutilation by my service provider. (There are always third-party hacking/phishing concerns, of course, but those should also be illegal.) Now that I know that my ISP is corrupting the data of webpages, how can I believe it will provide me any unsecured webpage without suspecting it of altering the data in transit? Fundamentally, how can I trust what I see and do online?

In a related conclusion, this adds to my conviction that we need to roll out HTTPS ASAP to every website and deprecate the unsecured HTTP, which can allow for this. It's not a solution to every potential problem, but it can help a lot.
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Lennart Kolmodin's profile photoSean Leather's profile photo
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Telkom doesn't block any protocols as far as I know. I suspect they may be throttling some, but I've never experienced any blocking.

I've considered paying for a VPN. I've used ssh tunneling to the US, but the connection was unbearably slow. The latency getting in and out of Africa is really bad. Given that, I haven't been motivated to do more research on the matter.

Sean Leather

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If you can't find a place to park, just make your own. #SouthAfricanQuirk
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I think that is just a truck quirk. :)
 
Lots of juicy tidbits here.
GHC has implemented "The Applicative Monad Proposal", meaning the Applicative typeclass is now a superclass of Monad . This is a breaking change and your programs will need to be updated. Please see the GHC 7.10 Migration Guide on the GHC wiki. GHC has implemented the "Burning Bridges Proposal", ...
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Sean Leather

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#HeForShe  
The movement for gender equality was originally conceived as a struggle led only by women for women. In recent years men have begun to stand-up in addressing inequalities and discrimination faced by women and girls. A Solidarity Movement for Gender Equality. Now it's time to unify our efforts.
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Have them in circles
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Sean Leather

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An excellent problem. Give it a shot!
A short game sheds light on government policy, corporate America, and why no one likes to be wrong.
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Sean Leather

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In general, I'm wary of mergers, but Telkom needs some competition in the wired segment. See my previous posts on Telkom's ADSL web page hijacking.
Industry regulators have approved Vodacom's bid to buy Neotel, along with its fixed-line network, making it a formidable competitor to Telkom.
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Sean Leather

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Investools (from TD Ameritrade) is an email spammer without shame.

First, they say “you will not receive further correspondence from Investools at this email address.” Next, they back-step that statement by asking you to “allow 30 days for this to take effect.” Finally, they continue to send you email, which I can only presume will stop 30 days after the first time I unsubscribed.

And the above only hold true for some emails from Investools that include an unsubscribe link. For another category of emails that links to your account preferences, disabling all email sending preferences does not actually prevent any emails from getting sent to you. There is also no mention of allowing 30 days for the change to take effect.

At first, I avoided reporting Investools emails as spam to Google, because I did, after all, subscribe to the service. However, I have come to the conclusion that their emails are definitely spam as they continue to email me despite me performing the action that instructs them to stop. It is absurd that any instruction to cease correspondence should take 30 days to take effect.
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Robert Byrne's profile photoSean Leather's profile photo
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Wow, definitely negative. ;)

Sean Leather

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Applied Functional Programming (AFP) Summerschool
Utrecht, Netherlands
6 - 17 July 2015

The summerschool teaches at both beginner and advanced levels via lectures and lab exercises. More info can be found here:

λ http://www.utrechtsummerschool.nl/courses/science/applied-functional-programming-in-haskell
λ http://foswiki.cs.uu.nl/foswiki/USCS
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Sean Leather

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A strange place with strange people, but a very good article nonetheless...
 
Wow, the US is such a strange place!
Textbook watchdogs Mel and Norma Gabler are good, sincere, dedicated people, who just may be destroying your child’s education.
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I would say decent, sure. But rational? Not in general, no.
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Education
  • Utrecht University
    present
  • University of Texas at Austin
  • Washington University in St. Louis
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Introduction
I'm a PhD student in Computer Science at Utrecht University in the Netherlands. I've been in school for most of my life. One of these days, I'll figure out what I'm going to do once I get out.
Work
Occupation
PhD Student
Employment
  • Anue Systems
  • IBM
  • Cray
  • Rockwell Collins
  • Boeing
Places
Map of the places this user has livedMap of the places this user has livedMap of the places this user has lived
Currently
Pretoria, South Africa
Previously
Utrecht, Netherlands - Austin, TX, USA - St. Louis, MO, USA - Chattanooga, TN, USA
Sean Leather's +1's are the things they like, agree with, or want to recommend.
The Amazing Story of Lookout Mountain’s Forgotten Incline Railway | Root...
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Harriet Whiteside was one of the richest people in Chattanooga, and the legacy of her controversial railway still shapes Lookout Mountain to

Vodacom-Neotel deal should worry Telkom, says analyst
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Industry regulators have approved Vodacom's bid to buy Neotel, along with its fixed-line network, making it a formidable competitor to Telko

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subhask - Type safe interface for working in subcategories of Hask

But didn’t Hitler grow up to be Hitler?
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Low hanging fruit today, but here's Televangelist Pat Robertson's advice to the mother who just lost her baby: As far as God’s concerned, He

Dark Mail Technical Alliance
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Our Mission. To bring the world our unique end-to-end encrypted protocol and architecture that is the 'next-generation' of private and secur

Folding the Hakama
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How to Fold the Hakama. Step 1 hakama1. Hold the koshi-ita under the chin, and the front of the hakama with your left hand. Move the gusset

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Follows industry-accepted best practices, Tells users about government data demands, Discloses policies on data retention, Discloses governm

Estonia: A Model for e-Government | June 2015 | Communications of the ACM
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Over the next decade, the population of Estonia is expected to soar more than 600% as the country becomes the first in the world to open its

Amazing maps show where Americans come from and who we really are today ...
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You'll never look at the country quite the same way after seeing these maps

Galapagos tortoise, aged 150, put down in California - BBC News
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A 150-year old Galapagos tortoise has been put down in California after suffering from arthritis and numerous other ailments.

You Have Your History, I Have Mine
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Good riddance to a scripted past populated by heroic stick figures in iffy moralistic parables. But is there nothing we can agree on?

Docker Docs
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Mac OS X. You can install Docker using Boot2Docker to run docker commands at your command-line. Choose this installation if you are familiar

South Africa’s cheapest bank accounts
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Worker union Solidarity has released its latest Bank Charges report, ranking the cheapest bank accounts in South Africa across all income gr

The American Medical Association is finally taking a stand on quacks lik...
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A new policy adopted at the association's annual meeting this week will create guidelines for media doctors and pathways of discipline for t

IT salaries in South Africa – what people really earn
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The MyBroadband salary survey reveals the average salaries of South African IT and telecommunications professionals

African Undersea Cables
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Update April 2015 French version now available. Cliquez ici pour la version française. Please contact me if you'd like a copy of the map in

Ally Skills Tutorial at ICFP
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I just signed up for the Ally Skills Tutorial at ICFP, and if you are (1) a man who (2) will be at ICFP in Vancouver, I encourage you to sig

Adblock Plus and (a little) more: Adblock Browser is here
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Adblock Browser is here · 2015-05-20 11:07 by Ben Williams. Today we are pleased to announce Adblock Browser for Android, our first foray in

Well-kept, finely decorated environment with a convenient location for visiting Gold Reef City and other areas of southern Johannesburg. We are a couple who stayed one night over a weekend in July to go to the Gold Reef City Casino to see a show. The facilities were mostly comfortable. Our main complaint was that our deluxe double room was cold. The large bedroom was heated by one wall panel heater, which is not sufficient in the middle of the South African winter. Naturally, the bathroom floor and shower walls, being tile, were also cold, but this is not unusual for these kinds of houses. The owners were pleasant and helpful. I enjoyed talking to Eddie about cricket and to his friendly bird who visited my shoulder. The breakfast food was simple but fine. We do think the logistics of breakfast could be done better. There was some confusion about where to find items for drinking tea and eating cereal. Other parties had problems with their orders. Perhaps it would be better to arrange not just the time of breakfast but also the order the day before the meal. Overall, the experience was not too unpleasant. We might consider returning to Villa Lugano in the summertime.
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Public - 11 months ago
reviewed 11 months ago
The Rhino and Lion Nature Reserve is a nice place to go for a day trip to see some animals. It's kind of like a big zoo without all of the cages except for the big predators, who have large separate fenced areas for each group (brown lions, wild dogs, white lions, and cheetahs). However, the reserve is not so big that you won't see everything in a day. Unlike the Kruger National Park, you don't have to drive around for hours wondering if you'll see lions. On the other hand, the reserve is not as wild as the park, and much of that mystique is missing. Be sure to plan your trip in advance. Look up the lion feeding time and other events. These are important for getting the most out of your trip. If you have a utility vehicle or 4x4, definitely bring it. None of the roads are paved, and in some areas, e.g. the cheetahs, you will really struggle in a 2-door hatchback like we had. Overall, we enjoyed it. The staff was helpful. The food at the Boma Restaurant was pretty good. If you're staying in the Johannesburg/Pretoria area and want to see some wild animals, you should check out the Rhino and Lion Nature Reserve.
• • •
Public - 11 months ago
reviewed 11 months ago
Fabulous! My fiancée (now wife) booked the honeymoon package at Elephant Hide in Knysna. First of all, let's put aside the fact that Knysna is gorgeous and completely worth your while. There's plenty to see and do. It's one of the rare places that I actually want to visit again. Let me just say that Elephant Hide is unbelievably fantastic. The people (Ryan, Mandy, Fish, and Eliot) are all very nice, helpful, and accommodating. The room was extremely comfortable. The view of the lagoon from our bedroom, bathroom, AND shower room was outstanding. The breakfast was delicious. And the location is very convenient while also being very quiet. Oh, and I'm told that the package price was pretty good, too. I would definitely recommend Elephant Hide to anyone. I'd also stay there again, myself.
• • •
Public - a year ago
reviewed a year ago
36 reviews
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Map
Map
A great place to learn about snakes and other creepy crawlies. James, our tour guide, was very knowledgeable and made it a fun and enjoyable experience. He even convinced my wife (who doesn't like snakes) to hold a Burmese python!
Public - a year ago
reviewed a year ago
Great burger and grilled tiger prawns. Superb view from every table.
Public - a year ago
reviewed a year ago
Nice place. Not fancy, just right.
Appeal: Very GoodFacilities: Very GoodService: Very Good
Public - 2 years ago
reviewed 2 years ago