Private university Updated 2025-07-16
Read the full article
Erhu player Updated 2025-07-16
Read the full article
Privacy coin legality Updated 2025-07-16
Read the full article
Super Mario World Updated 2025-07-16
Read the full article
Wall Street Updated 2025-07-16
Read the full article
Universal Turing machine Updated 2025-07-16
View more
A Turing machine that simulates another Turing machine/input pair that has been encoded as a string.
In other words: an emulator!
The concept is fundamental to state several key results in computer science, notably the halting problem.
Read the full article
Foundation series Updated 2025-07-16
Read the full article
Fraudster Updated 2025-07-16
Read the full article
Tree representation Updated 2025-07-16
View more
This section is about ways in which you can represent a tree.
Trees are a specific type of graph, so any graph representation also provides a way to represent a tree.
Therefore this section will focus only on methods specific to tress, and which cannot be used for graphs in general.
Read the full article
Sponsor Ciro Santilli's work on OurBigBook.com / Updates Updated 2025-07-16
Read the full article
Mutation Updated 2025-07-16
Read the full article
An overview of recent non-standard Bitcoin transactions by 0xB10C Updated 2025-07-16
View more
Read the full article
PayPal founder Updated 2025-07-16
Read the full article
Search engine optimization Updated 2025-07-16
Read the full article
Vacuum engineering Updated 2025-07-16
View more
Video 1.
Air-tight vs. Vacuum-tight by AlphaPhoenix (2020)
Source. Shows how to debug a leak in an ultra-high vacuum system. Like every other area of engineering, you basically bisect the machine! :-) By Brian Haidet, a PhD at University of California, Santa Barbara.
Read the full article
Public university Updated 2025-07-16
Read the full article
Apache Jena CLI tools setup Updated 2025-07-16
View more
The CLI tools don't appear to be packaged for Ubuntu 23.10? Annoying... There is a package libapache-jena-java but it doesn't contain any binaries, only Java library files.
To run the CLI tools easily we can download the prebuilt:
sudo apt install openjdk-22-jre
wget https://dlcdn.apache.org/jena/binaries/apache-jena-4.10.0.zip
unzip apache-jena-4.10.0.zip
cd apache-jena-4.10.0
export JENA_HOME="$(pwd)"
export PATH="$PATH:$(pwd)/bin"
and we can confirm it works with:
sparql -version
which outputs:
Apache Jena version 4.10.0
If your Java is too old then then running sparql with the prebuilts fails with:
Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.UnsupportedClassVersionError: arq/sparql has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:756)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:473)
        at java.net.URLClassLoader.access$100(URLClassLoader.java:74)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:369)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:363)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:362)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
        at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:621)
Build from source is likely something like:
sudo apt install maven openjdk-22-jdk
git clone https://github.com/apache/jena --branch jena-4.10.0 --depth 1
cd jena
mvn clean install
TODO test it.
If you make the mistake of trying to run the source tree without build:
git clone https://github.com/apache/jena --branch jena-4.10.0 --depth 1
cd jena
export JENA_HOME="$(pwd)"
export PATH="$PATH:$(pwd)/apache-jena/bin"
it fails with:
Error: Could not find or load main class arq.sparql
as per: users.jena.apache.narkive.com/T5TaEszT/sparql-tutorial-querying-datasets-error-unrecognized-option-graph
Read the full article
Privacy coin vs cryptocurrency tumbler Updated 2025-07-16
View more
Read the full article
3D file format Updated 2025-07-16
View more
Read the full article
Polymer Updated 2025-07-16
Read the full article

Unlisted articles are being shown, click here to show only listed articles.