Understanding the Fourier transform » #AltDevBlogADay. Yes, I realize that after reading the title of this post, 99% of potential readers just kept scrolling. So to the few of you who clicked on it, welcome! Don’t worry, this won’t take long. A very long time ago, I was curious how to detect the strength of the bass and treble in music, in order to synchronize some graphical effects. I had no idea how to do such a thing, so I tried to figure it out, but I didn’t get very far. What I found was the Discrete Fourier Transform (DFT), which looks like this: This formula, as anyone can see, makes no sense at all. Eventually, I was able to visualize how it works, which was a bit of a lightbulb for me. Disclaimer: my math skills are pitch-patch at best, and this is just intended to be an informal article, so please don’t expect a rigorous treatment.
A quick bit of background – what does the Fourier transform do? The picture on the left shows 3 cycles of a sine wave, and the picture on the right shows the Fourier transform of those samples. Eventually Consistent - Revisited. I wrote a first version of this posting on consistency models about a year ago, but I was never happy with it as it was written in haste and the topic is important enough to receive a more thorough treatment. ACM Queue asked me to revise it for use in their magazine and I took the opportunity to improve the article. This is that new version.
Eventually Consistent - Building reliable distributed systems at a worldwide scale demands trade-offs between consistency and availability. At the foundation of Amazon's cloud computing are infrastructure services such as Amazon's S3 (Simple Storage Service), SimpleDB, and EC2 (Elastic Compute Cloud) that provide the resources for constructing Internet-scale computing platforms and a great variety of applications. Under the covers these services are massive distributed systems that operate on a worldwide scale.
Historical Perspective In the mid-'90s, with the rise of larger Internet systems, these practices were revisited. Client-side Consistency. Age of the Algorithm. Content farms depend heavily on search engines for traffic. Photograph by Marc Rimmer. SOUTH BEND, Ind. —Tony Bucciferro put the Michigan State Spartans on his back Sunday and spurred them to a 3–0 win over the Notre Dame Fighting Irish (7–11) at Frank Eck Stadium.Bucciferro kept the Fighting Irish off the board during his nine innings of work for Michigan State (12–4). He struck out five and allowed one walk and three hits. This generic piece of sports reporting is remarkable for only one reason: a computer algorithm wrote it.
Simply put, an algorithm is a series of instructions that, if properly followed, can lead to the solution of a problem. As computers have become faster and more powerful—and as the costs of storage and bandwidth have plummeted—there is virtually no limit to the specificity, size and complexity of computer algorithms. The algorithm that changed the world was developed in 1998 by two Stanford doctoral students named Larry Page and Sergey Brin. I began my rewrite. Techno-optimism. ‘‘Are you optimistic or pessimistic about the future?’’ It’s a question I get asked so often that I have a little canned response I can rattle off without thinking: ‘‘In order to be an activist, you have to be both: pessimistic enough to believe that things will get worse if left unchecked, optimistic enough to believe that if you take action, the worst can be prevented.’’
But there’s more to it than that. I’ve been called a techno-utopian. I don’t know about that, but I’ll at least cop to ‘‘techno-optimist.’’ To understand techno-optimism, it’s useful to look at the free software movement, whose ideology and activism gave rise to the GNU/Linux operating system, the Android mobile operating system, the Firefox and Chrome browsers, the BSD Unix that lives underneath Mac OS X, the Apache web-server and many other web- and e-mail-servers and innumerable other technologies. ‘‘Bug Description: Microsoft has a majority market share in the new desktop PC marketplace.
This isn’t new. Electronic Frontier Foundation | Defending Freedom in the Digital World. Mob-sourcing: the prejudice of crowds. As more web content is crowd sourced and crowd moderated, are we seeing only the wisdom of crowds? No, we're also seeing their prejudice. The Internet reflects both the good and ugly in human nature. Mob-erating the web Over the weekend I listed some stuff on Craigslist. Later an anonymous person wrote saying that I looked like a business and would be flagged in violation of the Craigslist terms of use. They said the fact that I accepted credit cards was a “bright line.
" I wrote and said I was a brand-new customer of SquareUp.com, a company that enables smart phone owners to accept credit card payments. The next morning Craigslist sent me an e-mail saying my posting was deleted. Craigslist has its own minimal requirements: no pet sales, no sales of illegal merchandise, etc. For example, one man's listing for a low mileage 35-year-old car was apparently flagged because readers thought he wanted too much money for it.
The study isn't proof that crowd-moderators are biased against gays. Tummeling & the Twitter Chat: A Network Map of #IDEACHAT by ORGNET.COM. Network Weaving. Sunday Post on Crypto, Trust, and Political Action on the Web — Outsourced to David P. Reed « The Inverse Square Blog. I’m a lurker (mostly) on a listserv for MIT’s Center for Future Civic Media (C4), which pops up some fascinating discussions about news, social networking, and political life on and through the web. That announcement was followed by the effective end of the project, which had aimed at providing political dissidents secure ways to communicate. That sequence of events led to considerable back and forth among the C4 community, in part looking at the perennial problem of hype in the tech/software world outpacing reality. The more significant strand to the convesation (it seemed to me) focused on something else: the underlying issue of whether or not it is possible to produce a genuinely secure set-up that could enable the kind of sunlight the Iranian dissidents sought (and needed) and their supporters outside Iran hoped to provide.
The shorter, just to get you going: computer/information security depends on two factors: the technical/technological and the human. And now to the whole thing: Internet Explorer cannot display the webpage. Viral Ideas are grassroots innovations that start at the edges of networks and industries, take only small investments to begin, yet build through social and technical opportunism to swamp entrenched, vertically integrated companies.
True virality scales without bound, entails small startup costs, and grows in power with adoption. Spreadsheets are an example: they came from an apartment, began on the Apple II, and each new user refined them for others. Viral Spaces research is about places where people communicate, both at a distance and locally, with each other. We develop technologies of connection. Our goal is to demonstrate ideas that facilitate discourse between real people in real places where networks and computing enhance that dialogue. This can entail creative interactions as well as transactional ones. The Croquet Project. ...a new open source software platform for creating deeply collaborative multi-user online applications. It features a network architecture that supports communication, collaboration, resource sharing, and synchronous computation among multiple users.
Using Croquet, software developers can create powerful and highly collaborative multi-user 2D and 3D applications and simulations. For Mac, Linux, and Windows Platforms! In order to reduce the load on our servers, the Croquet SDK is being made available via BitTorrent. Click here for more information on BitTorrent. News/Events Croquet SDK 1.0 Beta is available! Julian Lombardi and David P. Several Croquet-related papers were recently delivered at The Fourth International Conference on Creating, Connecting and Collaborating through Computing (C5 2006).
Click here for more news about Croquet. Dpr. What do we teach when we teach science in school? And really, why do we teach science that way? I’ve personally never been quite sure whether I’m more of a scientist, engineer, or mathematician. The public lumps these all together for some reason, perhaps because they all appear to deal with concepts that are expressed in terms that must be learned carefully, because they certainly are not wired into our brains, and they aren’t the basis of popular culture either, unlike literature, art, history, sports, etc.
The science we teach is pretty old. We don’t teach kids ancient Greek and French cave drawing first, do we? I’ve heard lots of reasons for teaching “old” science, and old models and definitions taught as facts, over the years, and the reasonsnever really made a lot of sense. What got me bugged about this issue was reading a really fascinating book I’ve recommended to many people recently: The Blind Spot: Science and the Crisis of Uncertainty by William Byers. 2) Is there nothing? David P. Reed Biography. Dr. David P. Reed enjoys architecting the information space in which people, groups and organizations interact. He is well known as a pioneer in the design and construction of the Internet protocols, distributed data storage, and PC software systems and applications. He is co-inventor of the end-to-end argument, often called the fundamental architectural principle of the Internet.
Recently, he discovered Reed's Law, a scaling law for group-forming network architectures. Along with Metcalfe's Law, Reed's Law has significant implications for large-scale network business models. His current areas of personal research are focused on densely scalable, mobile, and robust RF network architectures and highly decentralized systems architectures. Research Career Beginning in the year 2001, Dr. He also made major contributions to research on security and resource management in time-shared, multiprocessor computer systems as part of the Multics project. As a student at MIT, Dr. Dr. MondoNet, a global wireless mesh network. MondoNet, a global wireless mesh network Sepp Hasslberger 7th May 2011 According to an article in ITWire A team from Rutgers University is trying to create the next generation version of the Internet, dubbed MondoNet, based on a global mesh of wireless access points that would be resistant to surveillance and state censorship and control.
The head of the project, Aram Sinnreich, is an assistant professor at Rutgers University’s School of Communication and Information. Introducing MondoNet: The censor-proof, unsurveillable network There is a draft paper – Weaving a New ‘Net: A Mesh-Based Solution for Democratising Networked Communications – which is soon to be published, that explains the concept of MondoNet. The ten ‘social specifications’ given for the proposed new net are: 10 Social Specifications for a Democratized Network 1. Arts and Culture - Jonathan Shapiro on ‘The Tyranny of Dead Ideas’ Jonathan Shapiro on ‘The Tyranny of Dead Ideas’ Posted on Mar 27, 2009 By Jonathan Shapiro Matt Miller is a one-man economic stimulus package. His ambitious new book, “The Tyranny of Dead Ideas: Letting Go of the Old Ways of Thinking to Unleash a New Prosperity,” has more intriguing proposals packed into it than might be found in a month of congressional debates.
“America’s economy is about to face its most severe test in nearly a century … [yet] our business and political leaders are doing next to nothing to prepare us to cope with what lies ahead,” Miller writes. The Tyranny of Dead Ideas By Matt Miller Times Books, 272 pages The proof is in their actions. The first step, Miller argues, is to recognize that “our entire economic and political culture remains in thrall to a set of `Dead Ideas’ about how a modern economy should work.” The problem is not in the stars, or even our institutions, but rather in our heads.
Miller lists the dead ideas that cloud our thinking: New and Improved Comments. Single Point of Failure. A single point of failure (SPOF) is a part of a system that, if it fails, will stop the entire system from working.[1] They are undesirable in any system with a goal of high availability or reliability, be it a business practice, software application, or other industrial system.
Overview[edit] Systems can be made robust by adding redundancy in all potential SPOFs. For instance, the owner of a small tree care company may only own one wood chipper. If the chipper breaks, he may be unable to complete his current job and may have to cancel future jobs until he can obtain a replacement. Redundancy can be achieved at various levels. The assessment of a potential SPOF involves identifying the critical components of a complex system that would provoke a total systems failure in case of malfunction. Computing[edit] In computing, redundancy can be achieved at the internal component level, at the system level (multiple machines), or site level (replication). Other fields[edit] See also[edit] Concepts: Aramis, or the Love of Technology: Bruno Latour. Computer Chips Seem Poised to Shrink Again. A Moore’s Law for Technology Services? - Bits Blog - NYTimes.com#more-4687#more-4687. Could there be a kind of Moore’s Law that would cover predictable advancement in complex technology consulting services?
It’s a question that people familiar with the services business might find comical and perplexing. Services engagements are called engagements for a reason. They’re often one-off hand-holding proposals with indefinite ends. So it seems tough for a company to claim any type of consistent improvement in services performance where a client could expect to see, say, twice as much efficiency every couple of years. But I.B.M. — who else? That’s right. In industry parlance, a service system could be anything from a company to a university, a government body or a water management plant.
I.B.M.’s big push these days revolves around making these types of service systems smarter. Mr. “We build these very, very complex systems, and they have these unintended consequences we didn’t foresee,” Mr. Such talk sounds borderline techno-utopian, although Mr. The problem with the iPad and Facebook. I loved Napster. I saw Napster as a fundamentally important social innovation when it came out in 1999. These thoughts were brought to my mind as I recently heard of Shawn Fanning and his new venture.
The original Internet was designed as a peer-to-peer system, like Napster was. Up until around 1993, the Internet had only one model of connectivity. Computers were assumed to be always on and always connected. The goal of the original Arpanet after 1969 was to share computing resources through integrating networks and allowing every host to be an equal player. Reach together with symmetry and equality were the things that made the Internet such a radical social innovation. The explosion of the Internet in 1993 – 1994 was largely the result of the web browser and a different logic: the client-server protocol.
It was not about symmetry and equality any more. The client-server model was not the only development that changed usage patterns. Thank you Larry Lessig, Clay Shirky and Andy Oram. xWeb. BEinGRID - Business Experiments in Grid: BEinGRID. Visualizing the Wikileaks Data.
Vision Statement: Mapping the Social Internet. WHAT WE CANNOT PREDICT - An EDGE Special Event. Internet electricity use is huge, but industry isn't worried - May. 3. Tomboy : Simple note taking. What is Bitcoin? - We Use Coins. Games. Track Google Sidewiki Comments Via RSS. Gears. Google Buzz and hybrid blogging - O'Reilly Radar. Blogging Software, Business Blogs & Blog Services at TypePad.com. Fring. Product Managers & Marketers: What The Internet of Things Means For You. Optimized » Blog Archive » Umeshisms. Social Steganography: Learning to Hide in Plain Sight. Social Steganography: Learning to Hide in Plain Sight. The 'Web Squared' Era - Forbes.com.
UK Startup Failbetter Games: Steampunk, Storytelling, Flowcharts, and Twitter as a Gaming Platform. US CIO Kundra Calls for Web 2.0 Co-Creation of Knowledge With Citizens. A Little Perspective (Digg, Twitter, Facebook) Version 4. Virulent Word of Mouse. Grassroots Mapping: tools for participatory and activist cartography. A-Z of the new technology, new products, new trends changing agriculture. Cutting back on your long list of passwords. The Art of Analog Computing | Elastika. Swype Reinvents Typing on Touch-Screen Phones. Mapping, Circumventing, Translating, Sharing. Cell Phones, Microwaves And The Human Health Threat. Byliner.
The New York Times’ R&D Lab has built a tool that explores the life stories take in the social space. SocialCalc Comes Out of Beta, Marking 30th Anniversary of VisiCalc, the first Spreadsheet Technology - ReadWriteEnterprise. The Litl Webbook: A more social computing device. Alan Sugar: iPod Will Die - Worst Predictions. Time Explorer. Today’s CAD Packs a Lot: TimeCompression.com. Book - VisMaster. Combinatorial Auctions. Genetic Programming and Data Structures. Conference on Systems Engineering Research. Piazzza Gives Classmates An Online Forum To Trade Their Knowledge.
View the iPad as a magazine opportunity, not a container. Snap to the graph, not the grid. Self-Reconfigurable Robots. Technology Review: Blogs: Jason Pontin's blog: Davos Day 3: Technology Is Like Magic. What Defines a Meme? Required reading – An anthropological introduction to YouTube | FreshNetworks Blog. Analytics X - Home. Infotention Part One: Dashboards, Radars, Filters. Linked data creates a new lens for examining the U.S. Civil War. Fix reviews' grammar, improve sales - A Computer Scientist in a Business School. A Computer Scientist in a Business School. Infotention Part Two: Building Information Dashboards. Non-Randomness in Coin Flipping. Official SCAR Manual. Esther Dyson - Net World. Weekend Project: Experiment with Chrome OS by Installing "Vanilla" to a USB Drive.
FP-RosenfeldEvan - CS448B Data Visualization. Theory and practice of provenance. The power of random- Seemingly loopy technique could dramatically improve communications networks. Ushahidi :: Crowdsourcing Crisis Information (FOSS) The Ushahidi Blog. Twitter as Good as a Telephone Survey? Plugging water leaks with data. 66% of American adults have a home broadband connection in 2010, little changed from the 63% who did so in 2009. Gallager codes. The Problems With ‘Platforms’ The Politics of 'Platforms' Problems with Unscientific Security. "intelligent" Stamps and the Maturation of Augmented Reality. Lost in the Cloud. Why speed matters.
Data. Networks.