Nook sales crashed by over 66 percent during 2013 holiday season

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On Thursday, Barnes & Noble announced that “device and accessories sales” plummeted to $88.7 million during the October through December 2013 holiday period, a drop of 66.7 percent. The company attributed the drop to “lower unit selling volume and lower average selling prices.” Of course, that’s prime shopping season, when most retailers see a spike in sales. The company added that “digital content sales” were $36.5 million during the same time frame, a drop of 27.3 percent.

via Nook sales crashed by over 66 percent during 2013 holiday season | Ars Technica.

Weaknesses – Bitcoin

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An attacker that controls more than 50% of the network’s computing power can, for the time that he is in control, exclude and modify the ordering of transactions. This allows him to:

  • Reverse transactions that he sends while he’s in control. This has the potential to double-spend transactions that previously had already been seen in the block chain.
  • Prevent some or all transactions from gaining any confirmations
  • Prevent some or all other miners from mining any valid blocks

via Weaknesses – Bitcoin.

With less than 50%, the same kind of attacks are possible, but with less than 100% rate of success. For example, someone with only 40% of the network computing power can overcome a 6-deep confirmed transaction with a 50% success rate.

Many eyes on Earth

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By contrast, the swarm satellites’ cameras will always be on, photographing everything in their path and, owing to their numbers, will pass over the same points on Earth with a frequency of hours to a few days, depending on latitude.

The biggest customers of conventional commercial imaging satellites are governments, in particular intelligence agencies and the military. Prices can be prohibitive for many other potential users, including researchers,

via Many eyes on Earth : Nature News & Comment.

Because the swarms are still to be launched, scientists have yet to fully assess the quality of the imagery. But the satellites’ spatial resolutions of 1–5 metres are much higher than those of most scientific satellites. Landsat, NASA’s Earth-observation workhorse, for example, has a resolution of 15–100 metres depending on the spectral frequency, with 30 metres in the visible-light range.

How Not To Sort By Average Rating

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PROBLEM: You are a web programmer. You have users. Your users rate stuff on your site. You want to put the highest-rated stuff at the top and lowest-rated at the bottom. You need some sort of “score” to sort by.

via How Not To Sort By Average Rating.

CORRECT SOLUTION: Score = Lower bound of Wilson score confidence interval for a Bernoulli parameter

Say what: We need to balance the proportion of positive ratings with the uncertainty of a small number of observations. Fortunately, the math for this was worked out in 1927 by Edwin B. Wilson. What we want to ask is: Given the ratings I have, there is a 95% chance that the “real” fraction of positive ratings is at least what? Wilson gives the answer. Considering only positive and negative ratings (i.e. not a 5-star scale), the lower bound on the proportion of positive ratings is given by:

Backtracking, justifications, and the shitty shoe shuffle, but how will the world respond?

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As I know many of you know Huawei were investigated by the American Congress and we were given a “clean bill of health”. Well as journalists and analysts said “lots of ifs buts and maybe’s but no evidence of wrongdoing”, or my favourite “a report for vegetarians, no meat”, so in my definition no evidence of wrongdoing is a clean bill of health. Based on this lack of evidence of any wrongdoing, the American Congress said that Huawei should not be allowed into America, so based on all of these revelations, and there will be many more on America, should all other Governments ban American technology companies, especially Cisco and Juniper given their position in critical infrastructures?

via PRISM: Backtracking, justifications, and the shitty shoe shuffle, but how will the world respond? – John Suffolk.

a P2P microblogging platform

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This paper proposes a new microblogging architecture based on peer-to-peer networks overlays. The proposed platform is comprised of three mostly independent overlay networks. The first provides distributed user registration and authentication and is based on the Bitcoin protocol. The second one is a Distributed Hash Table DHT overlay network providing key/value storage for user resources and tracker location for the third network. The last network is a collection of possibly disjoint “swarms” of followers, based on the Bittorrent protocol, which can be used for efficient near-instant notification delivery to many users. By leveraging from existing and proven technologies, twister provides a new microblogging platform offering security, scalability and privacy features. A mechanism provides incentive for entities that contribute processing time to run the user registration network, rewarding such entities with the privilege of sending a single unsolicited “promoted” message to the entire network. The number of unsolicited messages per day is defined in order to not upset users.

via [1312.7152] twister – a P2P microblogging platform.

 

Reverse engineering my bank’s security token

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The toolset

Reverse engineering Android apps requires a few software tools. Here’s what I used for this project:

  • Android SDKProvides the adb command-line tool, which can pull APKs, data files and settings from the phone.
  • dex2jarConverts Android’s Dalvik executables into JARs, which are easier to reverse engineer.
  • JD, JD-GUIAn excellent Java bytecode decompiler.
  • EclipseA Java IDE to validate discoveries during the reverse engineering process.

via Reverse engineering my bank’s security token | Thiago Valverde.

Malicious advertisements served via Yahoo

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Clients visiting yahoo.com received advertisements served by ads.yahoo.com. Some of the advertisements are malicious. Those malicious advertisements are iframes hosted on the following domains:

  • blistartoncom.org (192.133.137.59), registered on 1 Jan 2014
  • slaptonitkons.net (192.133.137.100), registered on 1 Jan 2014
  • original-filmsonline.com (192.133.137.63)
  • funnyboobsonline.org (192.133.137.247)
  • yagerass.org (192.133.137.56)

via Malicious advertisements served via Yahoo | Fox-IT International blog.

The Mathematics of Gamification

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At Foursquare, we have a simple, first-principles based method of resolving proposed venue attribute updates. We can gauge each Superuser’s voting accuracy based on their performance on honeypots (proposed updates with known answers which are deliberately inserted into the updates queue). Measuring performance and using these probabilities correctly is the key to how we assign points to a Superuser’s vote.

The Math

Let’s make this more concrete with some math.

via The Mathematics of Gamification | Foursquare Engineering Blog.

Who won the 22nd IOCCC

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Here are the names and categories for the winners of the 22nd IOCCC:

via Who won the 22nd IOCCC.

IOCCC=International Obfuscated C Code Contest

The source for all the entries should compile and run.  I liked this one: Most catty

 horizontal_cat concatenates files horizontally and write the output to stdout. Each input file is padded with spaces on the right so that the original text alignments are preserved.