Web Observatories: Concepts, State Of The Art & Beyond

The Web Observatories are becoming common Internet practice. They are web sites targeting a community of practitioners, scientists or generally individuals within the context of a focused organization. Their goal is to inform, educate, facilitate the interaction and boost the collaboration of community members. Various existing technologies can be deployed for this purpose. Still, their integration into a coherent informational and collaborative environment remains largely ad hoc. In this paper we attempt to elucidate the concept web observatory and identify its characteristics and practices

A common ontology for multi-dimensional shapes

In recent years, digital shapes have become more and more widespread and have been made available in a plethora of online repositories. A systematic and formal approach for capturing and representing shape-related information is needed to facilitate its reuse and enable the demonstration of useful cross-domain usage scenarios. In this paper we present an ontology for digital shapes, called the Common Shape Ontology (CSO). We discuss the rationale, the requirements and the scope of this ontology, we present in detail its structure and describe the most relevant choices related to its development. Finally, we show how the CSO conceptualization is used in domain-specific application scenarios

Towards Efficient Decentralized Federated Learning

We focus on the problem of efficiently deploying a federated learning training task in a decentralized setting with multiple aggregators. To that end, we introduce a number of improvements and modifications to the recently proposed IPLS protocol. In particular, we relax its assumption for direct communication across participants, using instead indirect communication over a decentralized storage system, effectively turning it into a partially asynchronous protocol. Moreover, we secure it against malicious aggregators (that drop or alter data) by relying on homomorphic cryptographic commitments for efficient verification of aggregation. We implement the modified IPLS protocol and report on its performance and potential bottlenecks. Finally, we identify important next steps for this line of research

Recent papers

<p>My publications</p

CVs

<p>My various vitae</p

Distributed and Adaptive Collaborative Filtering

<p>A review. Perhaps outdated but still very valid. Incomplete at the end.</p

Towards Energy Autarcy at Farming Level

<div> <div> <div> <p>We design, implement and evaluate a software platform that cou- ples the smartness of the irrigation systems with the smartness of the energy sys- tems. The resulting simulation engine allows large scale and very detailed experi- mentation which allow irrigation experts to specify energy effective configurations that lead to the reduction of the irrigation cost through smart utili- zation of renewable energy sources. </p> </div> </div> </div

Smart Energy for Smart Irrigation

<div> <div> <div> <p>We design, implement and evaluate a software platform that couples the smartness of the irrigation systems with the smartness of the energy systems. The resulting simulation engine allows large scale and very detailed experimentation which allow irrigation experts to specify energy ef- fective configurations that lead to the reduction of the irrigation cost through smart utilization of renewable energy sources. </p> </div> </div> </div

Business Intelligence through Machine Learning from Satellite Remote Sensing Data

Several cities have been greatly affected by economic crisis, unregulated gentrification, and the pandemic, resulting in increased vacancy rates. Abandoned buildings have various negative implications on their neighborhoods, including an increased chance of fire and crime and a drastic reduction in their monetary value. This paper focuses on the use of satellite data and machine learning to provide insights for businesses and policymakers within Greece and beyond. Our objective is two-fold: to provide a comprehensive literature review on recent results concerning the opportunities offered by satellite images for business intelligence and to design and implement an open-source software system for the detection of abandoned or disused buildings based on nighttime lights and built-up area indices. Our preliminary experimentation provides promising results that can be used for location intelligence and beyond

Διδακτικές Σημειώσεις Γραμμικής Άλγεβρας

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