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Uncategorized

Create a European city map with population density

Datasets: – Urban morphological zones 2000 (EU): https://www.eea.europa.eu/data-and-maps/data/urban-morphological-zones-2000-2 – Population count (World): http://sedac.ciesin.columbia.edu/data/set/gpw-v4-population-count-rev10/ – Administrative regions (World): http://gadm.org/ The map is European since the “urban” data from the European Environmental Agency (EEA) only covers Europe. Caveats The UMZ data ended up in PostGIS with srid 900914. You can use prj2epsg.org to convert the contents of […]

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Uncategorized

How to create a world-wide PostgreSQL database of administrative regions

The GADM database contains geographical data for administrative regions, e.g. countries, regions and municipalities. As always, once you have the data in the right format, it is easy to import it into a database. The data is available from GADM in several formats. All data has the coordinate reference system in longitude/latitude and theWGS84 datum. […]

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Uncategorized

How to assess computers on your local area network

I teach children how to programm and do other things with technology in an organisation called Coding Pirates in Denmark, which aims to be a kind of scout movement for geeks. A best seller among the kids is learning how to hack and I see this as a unique opportunity to convey some basic human […]

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Uncategorized

Urban Mining – Gold from Airbags,

Airbag sensors There is a small amount of gold inside the Airbag sensor. The sensor contains a small gold-plated marble, which amounts to some tiny amount of gold. Integrated Chips One kilogram of chips contains 1-8 grams of gold (according to Archimedes Channel on YouTube). Judging from the video they look for gold in the […]

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recycling

Urban Mining – Platinum from Road-side Dust

These guys found that road-side dust contains 1000 DKK worth of platinum per 1 ton of dust. Cody explains that this concentration of platinum equals the amount found in good-quality platinum ore. Does the stretch of road matter? In a word, yes. The user Jafromobile commented that a car is likely to eject platinum particulates […]

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Hardware Robots

Urban Mining – Steel Scraps

While I intuitively like the concept of Urban Mining – we have all these precious raw materials within easy reach of robots – I know nothing about it. I want to remedy that with the best ignorance cure of all: YouTube! Please, see an exteneded list of videos at the bottom of this post. The […]

Categories
AI Machine Learning

How to do backpropagation in Numpy

I have adapted an example neural net written in Python to illustrate how the back-propagation algorithm works on a small toy example. My modifications include printing, a learning rate and using the leaky ReLU activation function instead of sigmoid. import numpy as np   # seed random numbers to make calculation # deterministic (just a […]

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Family

My Dad’s Early Life Story

In this post I will give a brief overview of my father’s (Georgios Kefaloukos) many activities in the early part of his life. After dinner today I decided to ask him about his life story, and took as many notes as I could. My writing may seem like a glorified enumeration of his many occupations […]

Categories
AI

No one in ad tech needs to know your name

I work in the ad tech industry, which means that I track people online for a living. Mainly, I do it because the industry has interesting computer science problems and because the job pays well. I will not defend ad tech. Mainly because ad tech is not important enough to humanity to defend. However, I […]

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Food

My recipe for dal

I love dal. Here is my simple recipe, which draws it’s inspiration from both India and the Mediterranean Region. Ingredients: – 200-300 g split red lentils – 1 onion – 2-3 cloves of garlic – 1 can of crushed tomatoes – coriander seeds – cumin – fresh mint – fresh coriander – water – salt […]