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Proxmox cluster on distant bare metal servers
I run a Proxmox cluster with three nodes that are set up on three rented bare-metal servers from OVH in different datacenters. This is a pretty unusual setup, because bare-metal rental companies to not allow bridging on their network interface. Bridging in a typical racked cluster In this context, bridging means that a single physical…
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Repairing a key fob with a broken button
A family member mentioned that she had a broken key fob for her garage door, in which the left button was inoperative. It seemed very likely that the switch itself was broken, so I offered to replace it. However, I did not have time to source a new switch, so I opted to wire a…
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Predicting Home Energy Consumption, the Data-Driven Way
At Hello Watt, we help residential energy consumers reduce their energy bills through various means. This involves estimating their electricity and gas consumption based on information we collect either over the phone or through a form. We developed Consumption Calculator, a new model that works very similarly to the previous model except its coefficients are…
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Domain Knowledge Aids in Signal Disaggregation; the Example of the Cumulative Water Heater
In this article we present an unsupervised low-frequency method aimed at detecting and disaggregating the power used by Cumulative Water Heaters (CWH) in residential homes. Our model circumvents the inherent difficulty of unsupervised signal disaggregation by using both the shape of a power spike and its temporal pattern to identify the contribution of CWH reliably.…
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Video and motion analysis with Skope
Over 2020 and 2021 I did hardware and software prototyping for Sites Technologies, using Raspberry Pi cameras with video processing, and IMU sensors with machine learning. This project also involved server infrastructure.
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The nightmare of Shingled Magnetic Recording for NAS drives
IT systems are like onions, they have layers. And when the bottom-most layer fails, everything follows. This is the story of our experience with WD Red hard disk drives at Hello Watt, and how even while following good practices of system administration, deceptive advertising can cause your business to lose weeks of work.
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Optimization of Google Ads bidding taking into account our influence on the market
In this article, we give a brief overview of the Google Ads platform from the point of view of an advertiser as well as its available performance indicators and controls. We show how a simple portfolio optimization method indicates we can increase our ad returns significantly. Finally, we design a more complex model that takes…
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PBCS: Efficient Exploration and Exploitation Using a Synergy between Reinforcement Learning and Motion Planning
The exploration-exploitation trade-off is at the heart of reinforcement learning (RL). However, most continuous control benchmarks used in recent RL research only require local exploration. This led to the development of algorithms that have basic exploration capabilities, and behave poorly in benchmarks that require more versatile exploration. For instance, as demonstrated in our empirical study,…
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The problem with DDPG: understanding failures in deterministic environments with sparse rewards
In environments with continuous state and action spaces, state-of-the-art actor-critic reinforcement learning algorithms can solve very complex problems, yet can also fail in environments that seem trivial, but the reason for such failures is still poorly understood. In this paper, we contribute a formal explanation of these failures in the particular case of sparse reward…
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Curiosity rover in Kerbal Space Program with working rocker-bogie suspension and differential
It’s always a privilege doing what I love for a living. This past two months I’ve been on Curiosity’s next-of-kin at the NASA Jet Propulsion Lab in Pasadena. On a boring evening, I started to try making a working Curiosity rover in Kerbal Space Program. The main two challenges were the rocker-bogie suspension and its…
Guillaume Matheron
Data scientist, PhD in computer science