Pac-Man Paradox

 

Video: https://m.facebook.com/VidAngel/videos/1314290985363781/

dendrogram

A dendrogram (from Greek dendro "tree" and gramma "drawing") is a tree diagram frequently used to illustrate the arrangement of the clusters produced by hierarchical clustering. - source: https://en.wikipedia.org/wiki/Dendrogram

In data mining and statistics, hierarchical clustering (also called hierarchical cluster analysis or HCA) is a method of cluster analysis which seeks to build a hierarchy of clusters. Strategies for hierarchical clustering generally fall into two types:

• Agglomerative: This is a "bottom up" approach: each observation starts in its own cluster, and pairs of clusters are merged as one moves up the hierarchy.
• Divisive: This is a "top down" approach: all observations start in one cluster, and splits are performed recursively as one moves down the hierarchy.

The results of hierarchical clustering are usually presented in a dendrogram.

source: Hierarchical clustering (wikipedia)

 

HSL and HSV (Hue, Saturation and Lightness/Value)

HSL and HSV (Hue, Saturation and Lightness/Value)

HSL and HSV are used in color pickers and sometimes to define gradients for data visualization. The popular GIS program ArcGIS historically applied customizable HSV-based gradients to numerical geographical data. HSL or HSV is often more convenient than RGB. The CSS 3 specification allows web authors to specify colors for their pages directly with HSL coordinates.

http://en.wikipedia.org/wiki/HSL_and_HSV describes the difference between HSL and HSV.

 

Note that HSB (brightness) is not the same as HSL, but is the same as HSV. Curiously, the Microsoft Office HSL color picker labels L “Lum” (luminosity), but appears to be the same as lightness.

 

The blue icons are displayed in grayscale by setting the saturation to zero using CSS.

 

BTW, CSS also offers hsla and rgba, which add the alpha channel to control opacity/transparency.

Panini Projection

The general Panini projection is suitable for architectural subjects, especially interiors. It works best for views with a single central vanishing point -- straight down a city street, or the aisle of a church, for example. It is an excellent 'de-fishing' tool.
 

Sources: http://wiki.panotools.org/The_General_Panini_Projection

nomogram

Graphical calculators such as this are known of nomograms, and are often both an art and a science.

Multiplying with a Parabola! For example,

using y = x²

8 x 5 = 40

Source: http://headinside.blogspot.com/2014/07/multiplying-with-parabola.html

Engineer on WordMap

http://wordmap.co/#engineer

Many of the words have audio pronunciations. Click on a word to hear it spoken.

The Indo-European connection is easily seen (click on the word in India).

The English word ‘mechanic’ is a synonym (click on Greece) and the Arabic-related languages have a word with some similarity to ‘mechanic’: muhundis.

Digital Twin

The concept of a digital representation of a building that can be analyzed prior to actually building it, as embodied by BIM. Digital models can now be dynamic rather than static, thereby staying in sync with the physical objects they are representing. This technology is called “digital twins,” the name coming from the “twinning” of the physical model with the digital. This AECbytes paper explores the technology of digital twins and its potential in the AEC industry to go much further than BIM in terms of impact and benefits.

“digital twin — a concept of having a real-time digital representation of a physical object. Usually, digital data is formed by sensors that continuously monitor changes in environment and report back the updated state in the form of measurements and pictures. … A digital twin is essentially a link between a real world object and its digital representation that is continuously using data from the sensors. All data comes from sensors located on a physical object”

“The digital representation is later used for visualization, modeling, analysis, simulation and further planning.”

“Technologies like augmented reality in construction are emerging to digitalise the construction industry, making it significantly more effective.”

Useful application of digital twins in construction

• Automated progress monitoring
• As-built vs as-designed models
• Resource planning and logistics
• Safety monitoring
• Quality assessment
• Optimization of equipment usage

Getting Data for Digital Twins

• Smartphone Cameras
• Time-Lapse Cameras
• Autonomous UAV and Robots
• Video Surveillance Cameras
• Head-mounted Cameras and Body Cameras

Image data processing algorithms for digital twin creation

• 3D Reconstruction: Conventional Photogrammetry
• 3D Reconstruction: Structure from Motion
• Object Detection and Recognition
• Localization
• Object Tracking

Full article:

Advanced Imaging Algorithms in Digital Twin Reconstruction of Construction Sites

Even an entire city can have a digital twin: Virtual Singapore

 

treemap

Introduced by Ben Shneiderman in 1991, a treemap recursively subdivides area into rectangles. As with adjacency diagrams, the size of any node in the tree is quickly revealed. “Squarified” treemaps use approximately-square rectangles, which offer better readability and size estimation than naïve “slice-and-dice” subdivision.
- D3.js provides a treemap for data visualization.

Seen below, this treemap shows the whole contents of a directory tree on your Windows hard drive. The treemap represents each file as a colored rectangle, the area of which is proportional to the file's size. The rectangles are arranged in such a way, that directories again make up rectangles, which contain all their files and subdirectories. So their area is proportional to the size of the subtrees. The color of a rectangle indicates the type of the file, as shown in the extension list. The cushion shading additionally brings out the directory structure.
- http://windirstat.info/

Personal Note

Back in the late 80s, I read Shneiderman’s book Designing the User Interface, which had a profound effect on me. One rule I still remember is 7 ± 2 because people can generally store 5 – 9 things in their short term memory. In application, this means that menus should have between 5-9 items. More than 9 requires the user to waste extra time sorting through all the options.