This is a good crisp summary that doesn't shy away from technical detail but steps through the major elements of blockchain technology with clarity and precision. The sections on blockchain components (section 3) and consensus models (section 4) are particularly strong. It even comes with a fun blockchain use case flowchart.
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Today we'll take a brief look at blockchain. Although presented as a type of currency, blockchain is in essence a graph technology. It creates a record of transactions by chaining them together such that you cannot change or revise one transaction without revising or changing all transactions. Because this is expensive and in some cases impossible, blockchain becomes a permanent record of transactions.
Topics in Distributed Ledger Technology
This is a presentation I gave twice this fall, summarizing some of the major themes in blockchain, describing how it works, surveying a number of applications, and discussing issues related to its use. https://www.downes.ca/presentation/495
The Blockchain Papers
This is a very large resource shared as a Google Doc assembling a lot of the reading I have done on blockchain over the last year or so. I am constantly contributing to it (and welcome suggestions or ideas for additional resources). Here's the link: https://docs.google.com/document/d/1DX5nYbkd5mQ81xrLggovceIkE43rCFrOMbFLYUkBhZQ/edit#
Building a Blockchain
I also built my own toy blockchain engine last spring. Here it is: https://halfanhour.blogspot.com/2018/03/building-blockchain.html It steps the reader through fundamental concepts of a blockchain and the major elements of a blockchain engine.
This is just the Beginning
Although this is the only day in the course dedicated specifically to blockchain, really what we should see is that blockchain is just one step in the narrative we've already been developing while talking about linked data and cloud technology, and a narrative that will continue through the remaining weeks of the course. As with the other topics in the course, it is possible to dive very deeply into the subject. From the perspective of E-Learning, though, the idea is to get an overview of what is happening and seek to apply it to a projection of likely trends in the next decade or so.
A reminder that this week's guest is Ben Werdmuller - the founder of Elgg, the founder of Known, and now working with Matter. We'll talk a bit about his work in the past but I'm far more interested to know where he sees the future of initatives like IndieWeb taking us in the years ahead. Please note that because of my travel on Wednesday, we will be having our chat on Thursday, November 8.
This week's task has three parts
- Create a model graph of some aspect of the E-Learning 3.0 course (it doesn't have to be an actual graph, only a representation of what an actual graph might look like. We've already seen, eg., graphs on the relations between people in the course. Could there be other types of graphs?
- In your model, consider how the states of the entities in that graph might vary. Consider not only how nodes might vary (eg., a person might have a different height over time) but also how the edges might vary (eg., a person might have a different strength of relation (calculated how?) with another person over time).
- In your model, consider how knowledge about the changes in states in the graph might be used.
No Newsletter Wednesday
Wednesday is a travel day for me, so we'll resume on Thursday.
This podcast transcript provides a level-headed overview of blockchain technologies focusing especially on the trade-offs the use of blockchain entails (for example: less efficient databases in exchange for immutability). There's also a nice table depicting the major use cases for blockchain. And there's a nice look at the different motivations for employing blockchain.
This is a long (136 page PDF) and detailed report on blockchains in education. The authors work slowly and deliberately in their pursuit of accuracy and clarity, which results in a presentation that will be easily understood by most readers. There is a wealth of examples in the document describing use cases, scenarios and pilot projects, and companies involved in the space.
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