Sudo remote auditing JSON plugin

This plugin for Sudo 1.83 and later reports all input (detects and omits password input) and output during each Sudo session to a remote TLS 1.2+ endpoint.


The format is Newline-Delimited JSON (ndjson), with one line per input or output event. If the TLS connection fails, the fall-back mechanism is a local log file for each Sudo session stored as “〈log-dir〉/〈id〉.ndjson” .

It runs on IBM AIX and Linux.

Port of Elasticsearch and Logstash to IBM AIX

First I ported ES and LS version 7.0.1. Then as new versions came out I ported 7.1.1, 7.2.0, and 7.4.0.

The customer needed to use Elasticsearch 6 and Logstash 6 (or later) under AIX 6 and 7, on IBM’s J9 Java platform.


As I started working on this I found out that there had recently been a release of OpenJDK for AIX 7 but it was not enough in this case.

FOP XML→PDF position tracker

Tracks the location of objects from the input XML into the PDF produced by Apache FOP (Formatting Objects Processor), for instance to know at which page to find a specific item.


The customer is a company that offers financial document management to their customers. Their document processing pipeline extracts and normalizes the content from various inputs, and uses Apache FOP for building the PDF views.

They needed to track the page in the produced PDF where specific elements were rendered.

Nigerian Oil Spill Monitor

→Demonstration, →Documentation

The software system used by the Nigerian National Oil Spill Detection and Response Agency (NOSDRA) for recording, mapping and monitoring oil spills. Allows the citizens and other stakeholders check the accuracy of those reports at


This work was done for the British NGO Stakeholder Democracy Network (SDN).

Try it out at the development site which includes the latest prototype features and enhancements:

Official site operated by SDN until April 2019, now by NOSDRA:

Nigerian Gas Flare Tracker

→Demonstration, →Documentation

A web application that, from satellite measurements, identifies gas flares in Nigeria, and estimates the energy wasted, value of gas burnt, missing fees (penalties for gas flaring are seldom enforced), potential for electricity generation, and CO₂ emissions.


This 2018 edition is the successor of the first Nigerian Gas Flare Tracker (GFT) I made in 2014, which was an adaptation of the Nigerian Oil Spill Monitor (OSM).

This work was done for the British NGO Stakeholder Democracy Network (SDN).

Official site operated by SDN until April 2019, now by NOSDRA:

eLearning Multi-Agent System

Developed for the German Research Center for Artificial Intelligence (DFKI).


The task was to design and implement a multi-agent system based on JADE that could be used for integrating the work of the project partners (academic research institutions from France and Germany), and then integrate the Learning Management System ILIAS as part of the system.

The integration was achieved by using "liaison" agents: small Java components that when linked into each partner's software gave it an agent representative in the system.

There was a liaison agent for each of the components:

  • ILIAS Learning Management System adapted by the DFKI
  • I-FLEG 3D virtual environment from INRIA
  • Dialog Manager from the University of Saarland
  • French and German chatbots for testing, based on AIML, not part of the project

Each agent can report the learner's progress using SCORM messages, a custom XML encoding of the standard SCORM API. I also built demonstration content for the project as SCORM packages to be loaded into the ILIAS LMS.

The learner agent has an AgentSpeak brain provided by Jason.

EC-TEL 2012 Conference poster in English

XML to JSON streaming converter

Reads a stream of XML files and writes a stream of line-oriented JSON according to a mapping file that describes which data to extract, and how to encode it in JSON.


It was done for Tahi Data Services (TDS) LTD PTE of Singapore. They needed to stream XML auditing logs from Solaris 9/10 and Oracle 11 to an aggregator that requires JSON format, and it has to work on legacy systems where only Java 5 is available.

Tutorial Toolkit

Tutorial feedback overlays for Java applications, just 24 KB compressed.


The translucent blue layer is a stencil that prevents the user from interacting with the components under it, making it easier for them to focus on the active components.

The screenshot shows a note-style call-out (another style is thought bubble) with four target buttons in the application (arrows), and one button for proceeding to the next step in the tutorial.

It's enough to specify the note content and targets, and Tutorial Toolkit finds the proper place for the call-out so that they don't get occluded, using a bespoke single-pass constraint solver.

This work was done in one month for the London Knowledge Lab, and was used in the MiGen project. It can be seen briefly in the video MiGen: Unlocking Algebra at 3'20" and 4'22".

Download (GPL license) TTK 1.0

Under dist/lib/ there is a ready to use JAR file: launch the demo application from the screenshot with

java -jar dist/lib/TTK-20121008.jar

Technical documentation in English

D3 animated multi-lingual chart

An example of a small, focused just-in-time component.


The bars grow from the bottom, the donuts grow clockwise, and all charts are multi-lingual.

The code for the different chart types (bar, multibar, donut) is encapsulated in the Charts object used for the example in the picture.

It was written from scratch in one day for a Belgian web design agency, using D3.js

VideoLecture player

Multi-stream web video player for interactive piano lessons.


The screenshot shows (paused) a live webcam RTMP stream, an MP4 H.264 video HTTP stream, an FLV video RTMP stream, and an F4V video HTTP stream. All can play at the same time and it uses either the Flash plug-in or HTML5 video.

This work was done in two weeks for the German Research Center for Artificial Intelligence (DFKI)

Manual in English