Generating Synthetic Time-Series Data For Smart-Building Knowledge Graphs Using Generative Adversarial Networks

[This blog post is based on Jesse van Haaster‘s bachelor thesis Artificial Intelligence at VU]

Knowledge Graphs represent data as triples, connecting related data points. This form of representation is widely used for various applications, such as querying information and drawing inferences from data. For fine-tuning such applications, actual KGs are needed. However, in certain domains like medical records or smart home devices, creating large-scale public knowledge graphs is challenging due to privacy concerns. To address this, generating synthetic knowledge graph data that mimics the original while preserving privacy is highly beneficial.

Jesse’s thesis explored the feasibility of generating meaningful synthetic time series data for knowledge graphs. He specifically does this in the smart building / IoT domain, building on our previous work on IoT knowledge graphs, including OfficeGraph.

To this end, two existing generative adversarial networks (GANs), CTGAN and TimeGAN, are evaluated for their ability to produce synthetic data that retains key characteristics of the original OfficeGraph dataset. Jesse compared among other things the differences in distributions of values for key features, such as humidity, temperature and co2 levels, seen below.

Key value distributions for CTGAN-generated data vs original data
Key value distributions for TimeGAN-generated data vs original data

The experiment results indicate that while both models capture some important features, neither is able to replicate all of the original data’s properties. Further research is needed to develop a solution that fully meets the requirements for generating meaningful synthetic knowledge graph data.

More details can be found in Jesse’s thesis (found below) and his Github repository https://github.com/JaManJesse/SyntheticKnowledgeGraphGeneration

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HEDGE-IoT project kickoff

The HorizonEurope project HEDGE-IoT started January 2024. The 3.5 year project will build on existing technology to develop a Holistic Approach towards Empowerment of the DiGitalization of the Energy Ecosystem through adoption of IoT solutions. For VU, this project allows us to continue with the research and development initiated in the InterConnect project on data interoperability and explainable machine learning for smart buildings.

Researchers from the User-Centric Data Science group will participate in the project mostly in the context of the Dutch pilot, which will run in Arnhems Buiten, the former testing location of KEMA in the east of the Netherlands. In the pilot, we will collaborate closely with the other Dutch partners: TNO and Arnhems Buiten. At this site, an innovative business park is being realized that has its own power grid architecture, allowing for exchange of data and energy, opening the possibility for various AI-driven services for end-users.

VU will research a) how such data can be made interoperable and enriched with external information and knowledge and b) how such data can be made accessible to services and end-users through data dashboards that include explainable AI.

The image above shows the Arnhems Buiten buildings and the energy grid (source: Arnhems Buiten)

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Explainable AI using visual Machine Learning

The InterConnect project gathers 50 European entities to develop and demonstrate advanced solutions for connecting and converging digital homes and buildings with the electricity sector. Machine Learning (ML) algorithms play a significant role in the InterConnect project. Most prominent are the services that do some kind of forecasting like predicting energy consumption for (Smart) devices and households in general. The SAREF ontology allows us to standardize input formats for common ML approaches and that explainability can be increased by selecting algorithms that inherently have these features (e.g. Decision Trees) and by using interactive web environments like Jupyter Notebooks a convenient solution for users is created where step by step the algorithmic procedures can be followed and visualized and forms an implementation example for explainable AI.

Read more, and watch our live demonstration video on the InterConnect project page.

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Simulating creativity in GANs with IoT

[This blog post is based on the Artificial Intelligence MSc thesis project from Fay Beening, supervised by myself and Joost de Boo, more information can be found on Fay’s website]

Recently, generative art has been one of the fields where AI, especially deep learning has caught the public eye. Algorithms and online tools such as Dall-E are able to produce astounding results based on large artistic datasets. One class of algorithms that has been at the root of this success is the Generative Adversarial Network (GAN), frequently used in online art-generating tools because of their ability to produce realistic artefacts.

but, is this “””real””” art? is this “””real””” creativity?

To address this, Fay investigated current theories on art and art education and found that these imply that true human creativity can be split into three types: 1) combinational, 2) explorative and 3) transformative creativity but that it also requires real-world experiences and interactions with people and the environment. Therefore, Fay in her thesis proposes to combine the GAN with an Internet of Things (IoT) setup to make it behave more creative.

Arduin-based prototype (image from Fay’s thesis)

She then designed a system that extends the original GAN with an interactive IoT system (implemented in an Arduino-based prototype) to simulate a more creative process. The prototype of the design showed a successful implementation of creative behaviour that can react to the environment and gradually change the direction of the generated images.

Images shown to the participant during the level of creativity task. Images 2 and 6 are creative GAN generated images. Images 1 and 5 are human-made art. Images 3 and 4 are online GAN generated art.

The generated art was evaluated based on their creativity by doing task-based interviews with domain experts. The results show that the the level to which the generated images are considered to be creative depends heavily on the participant’s view of creativity.

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Interconnect Project kickoff

On 1 October 2019, the Horizon2020 Interconnect project has started. The goal of this huge and ambitious project is to achieve a relevant milestone in the democratization of efficient energy management, through a flexible and interoperable ecosystem where distributed energy resources can be soundly integrated with effective benefits to end-users.

To this end, its 51 partners (!) will develop an interoperable IOT and smart-grid infrastructure, based on Semantic technologies, that includes various end-user services. The results will be validated using 7 pilots in EU member states, including one in the Netherlands with 200 appartments.

The role of VU is to develop in close collaboration with TNO extend and validating the SAREF ontology for IOT as well as and other relevant ontologies. VU will lead a task on developing Machine Learning solutions on Knowledge graphs and extend the solutions towards usable middle layers for User-centric ML services in the pilots, specifically in the aforementioned Dutch pilot, where VU will collaborate with TNO and VolkerWessel iCity and Hyrde.

Interconnect team photo, taken at the location of the kickoff meeting: the FC Porto stadium

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