To Dissect a Mockingbird:A Graphical Notation for the Lambda Calculus with Animated Reduction David C Keenan, 27-Aug-1996 last updated 10-May-200 The lambda calculus, and the closely related theory of combinators, are important in the foundations of mathematics, logic and computer science. This paper provides an informal and entertaining introduction by means of an animated graphical notation. Introduction In the 1930s and 40s, around the birth of the "automatic computer", mathematicians wanted to formalise what we mean when we say some result or some function is "effectively computable", whether by machine or human. A "computer", originally, was a person who performed arithmetic calculations. The "effectively" part is included to indicate that we are not concerned with the time any particular computer might take to produce the result, so long as it would get there eventually. They wanted to find the simplest possible system that could be said to compute.
We create concept maps, a type of model, to explore and learn about complex information spaces. By showing everything—the forest and the trees—in a single view, concept maps help people create mental models and clarify thoughts. We create concept maps to share understanding— with our clients, peers, and others interested in the subjects. Please note: many of our concept maps are poster size. They can be printed at smaller sizes (11 x 17), but may be difficult to read. A few of the maps have been printed and are available through our office.
with TwitterFriends you can ... * find out the hidden network of Twitter contacts that are really relevant for you. * visualize the network of your relevant contacts and their contacts * see who of your Twitter friends are online this very moment * read some stats about your Twitter account * take a look at the most conversational Twitterers or those who are posting the most links To see your relevant network and some stats about your tweeting behavior compared to other Twitter users, just enter your (or another) Twitter username: * Darren Rowse of Problogger Blog Tips wrote a nice review on TwitTip and calls TwitterFriends a "great Twitter statistics tool". Thanks, Darren! * Jason Annas even created a video explaining TwitterFriends. I think this is a great introduction to the tool, but see for yourself:
Q-tools The list below attempts to define a set of “Q-tools” that may be used to generate, sort, classify and perform operations on information. This is not intended to be an exhaustive list, but more of a starting point for discussion. I have also added some alternative names for each Q-tool. PrismA prism is a question that divides information into smaller groups. The purpose of a prism is to break down information into categories or subgroups. An example might be “What are the parts of this system?” Prisms are used extensively in scientific inquiry. They are also used in organization design to map the departments and sub-departments of a company. An example question used in this activity might be “What roles are required to deliver this functionality?” To create a prism, define a question that can be used to divide a unit of information into its constituent parts. Alternative names: Divider, separator, splitter, brancher.
Here’s a visualization concept I came up with a while back to look at the way search engines and word-of-mouth affects hit frequency on the iBiblio web-traffic log. iBiblio consists of around 420 sites. Each one of the circles you see represents one of the websites. The size of each pie slice inside grows with respect to the number of hits by individual search engines (see the legend for which ones). The size of the circle grows with respect to the overall number of hits by people other than search engines. Hits are counted by number of unique incoming IP addresses per day. Links get drawn between cliques of websites where more than 1/4th of the unique IP addresses are the same on that day, meaning, more or less, that those sites often share traffic. The total amount of data was around 10TB and the visualization took about a day to process into a static animation. The original is meant to run on a wall-sized (16′x9′) or on our specialized visualization dome.
With all that scope for reasonable disagreement, is there anything we can all agree on? How much of the hierarchy in the medal table is indisputable, and how much depends on your point of view? So we want to say that one country has done strictly better than another if the medal score of the latter can be transformed into the former by a sequence of medal additions and medal upgrades. A bit of thought shows that this is exactly equivalent to defining a partial order on triples of medals, in which a triple (G,S,B) is considered at least as good as another triple (g,s,b) if and only if it satisfies the three conditions * G ≥ g * G + S ≥ g + s * G + S + B ≥ g + s + b