Blog Post
The Myth of a Hacker-Proof IoT
I was recently invited to give a presentation on security for Internet of Things networking at infocomm 16. While I discussed the topic and scope with the organizers, I didn’t have a good catchy title prepared, so the organizers took it upon themselves to submit one for me: “Hacker-Proof IoT.” Easy, right? While I would… View Article
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How To Speed Up Python Code With Cython & PyPy: Part 1
When a Python program runs too slowly for our liking, there are several ways to speed it up. Our expert recently spent some time experimenting with two of the most popular tools: Cython and PyPy. This two-part post begins by delving into Cython.
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Building a Home Automation System (For Fun)
You’ll find that a lot of engineers like to tinker. In addition to the projects we work on for clients or employers, a lot of us like to put our skills to the test when it comes to our own homes, too. In my case, I wanted to try my hand at creating a home… View Article
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Your Phone’s for Footballin’: Compression Efficiency Matters Again
It’s likely that delivery efficiency is going to get more important in the future.
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What is CRC Networking? Understanding the Cyclic Redundancy Check
CRC stands for Cyclic Redundancy Check — an error-detecting code used to determine if a block of data has been corrupted. The mathematics behind CRCs may initially appear daunting, but don’t have to be. Our engineer presents an alternative explanation useful to the software implementor of CRCs.
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Spectral Analysis with the DFT
You may have encountered spectral analysis. The basic idea is to take a waveform, in our case an audio clip, and determine which frequency components are in it. This post provides a very brief overview of the Discrete Fourier Transform (DFT), spectrograms and DFT spectral analysis.
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ElcomSoft’s Hack of Image Authentication
There was some interesting news yesterday about the cracking of an image authentication mechanism built into Nikon cameras. The hack was announced in what seemed to me like a rather adolescent post on the ElcomSoft company blog: ElcomSoft Co. Ltd. researched Nikon’s Image Authentication System, a secure suite validating if an image has been altered… View Article
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Transforms for Video Compression, Part 3: The DCT and Why Transforming Is Valuable
The use of transforms in data compression algorithms is at least 40 years old. The goal of this three-part series of posts is to provide the mathematical background necessary for understanding transforms and to explain why they are a valuable part of many compression algorithms. I’m focusing on video since that’s my particular interest. Part… View Article
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Transforms for Video Compression, Part 2: Matrix Representation and 2D Transforms
The use of transforms in data compression algorithms is at least 40 years old. The goal of this three-part series of posts is to provide the mathematical background necessary for understanding transforms and to explain why they are a valuable part of many compression algorithms. I’m focusing on video since that’s my particular interest. Part… View Article
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Transforms for Video Compression, Part 1: Vectors, the Dot Product and Orthonormal Bases
The use of transforms in data compression algorithms is at least 40 years old. The goal of this three-part series of posts is to provide the mathematical background necessary for understanding transforms and to explain why they are a valuable part of many compression algorithms. I’ll focus on video since that’s my particular interest. Part… View Article
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Irrational Optimism and Project Planning
I read an article in the Wall Street Journal a couple of months ago that resonated strongly with me. Although the article deals with the problem of project planning for infrastructure projects, it’s really about irrational optimism. Why is it that infrastructure projects always cost more and take longer than expected? (As anyone reading this… View Article
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The Math Behind Analog Video Resolution
The world is moving in the direction of HDTV, but NTSC “standard def” signals are still common for many reasons and will remain so. One important reason is that cameras that output NTSC are widely available and cheap! Many applications, including a lot of security applications, simply don’t require the resolution of HDTV — and… View Article
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