209 research outputs found
Structured Knowledge Representation for Image Retrieval
We propose a structured approach to the problem of retrieval of images by content and present a description logic that has been devised for the semantic indexing and retrieval of images containing complex objects. As other approaches do, we start from low-level features extracted with image analysis to detect and characterize regions in an image. However, in contrast with feature-based approaches, we provide a syntax to describe segmented regions as basic objects and complex objects as compositions of basic ones. Then we introduce a companion extensional semantics for defining reasoning services, such as retrieval, classification, and subsumption. These services can be used for both exact and approximate matching, using similarity measures. Using our logical approach as a formal specification, we implemented a complete clientserver image retrieval system, which allows a user to pose both queries by sketch and queries by example. A set of experiments has been carried out on a testbed of images to assess the retrieval capabilities of the system in comparison with expert users ranking. Results are presented adopting a well-established measure of quality borrowed from textual information retrieval
URANUS: Radio Frequency Tracking, Classification and Identification of Unmanned Aircraft Vehicles
Safety and security issues for Critical Infrastructures are growing as
attackers adopt drones as an attack vector flying in sensitive airspaces, such
as airports, military bases, city centers, and crowded places. Despite the use
of UAVs for logistics, shipping recreation activities, and commercial
applications, their usage poses severe concerns to operators due to the
violations and the invasions of the restricted airspaces. A cost-effective and
real-time framework is needed to detect the presence of drones in such cases.
In this contribution, we propose an efficient radio frequency-based detection
framework called URANUS. We leverage real-time data provided by the Radio
Frequency/Direction Finding system, and radars in order to detect, classify and
identify drones (multi-copter and fixed-wings) invading no-drone zones. We
adopt a Multilayer Perceptron neural network to identify and classify UAVs in
real-time, with % accuracy. For the tracking task, we use a Random Forest
model to predict the position of a drone with an MSE , MAE
, and . Furthermore, coordinate regression is
performed using Universal Transverse Mercator coordinates to ensure high
accuracy. Our analysis shows that URANUS is an ideal framework for identifying,
classifying, and tracking UAVs that most Critical Infrastructure operators can
adopt
Automatic Support for Verification of Secure Transactions in Distributed Environment using Symbolic Model Checking
Electronic commerce needs the aid of software tools to check the validity of business processes in order to fully automate the exchange of information through the network. Symbolic model checking has been used to formally verify specifications of secure transactions in a system for business-to-business applications. The fundamental principles behind symbolic model checking are presented along with techniques used to model mutual exclusion of processes and atomic transactions. The computational resources required to check the example process are presented, and the faults are detected through symbolic verification
Semantic Blockchain to Improve Scalability in the Internet of Things
Generally scarce computational and memory resource availability is a well known problem for the IoT, whose intrinsic volatility makes complex applications unfeasible. Noteworthy efforts in overcoming unpredictability (particularly in case of large dimensions) are the ones integrating Knowledge Representation technologies to build the so-called Semantic Web of Things (SWoT). In spite of allowed advanced discovery features, transactions in the SWoT still suffer from not viable trust management strategies. Given its intrinsic characteristics, blockchain technology appears as interesting from this perspective: a semantic resource/service discovery layer built upon a basic blockchain infrastructure gains a consensus validation. This paper proposes a novel Service-Oriented Architecture (SOA) based on a semantic blockchain for registration, discovery, selection and payment. Such operations are implemented as smart contracts, allowing distributed execution and trust. Reported experiments early assess the sustainability of the proposal
Machine-learned Adversarial Attacks against Fault Prediction Systems in Smart Electrical Grids
In smart electrical grids, fault detection tasks may have a high impact on
society due to their economic and critical implications. In the recent years,
numerous smart grid applications, such as defect detection and load
forecasting, have embraced data-driven methodologies. The purpose of this study
is to investigate the challenges associated with the security of machine
learning (ML) applications in the smart grid scenario. Indeed, the robustness
and security of these data-driven algorithms have not been extensively studied
in relation to all power grid applications. We demonstrate first that the deep
neural network method used in the smart grid is susceptible to adversarial
perturbation. Then, we highlight how studies on fault localization and type
classification illustrate the weaknesses of present ML algorithms in smart
grids to various adversarial attacksComment: Accepted in AdvML@KDD'2
Counterfactual Fair Opportunity: Measuring Decision Model Fairness with Counterfactual Reasoning
The increasing application of Artificial Intelligence and Machine Learning
models poses potential risks of unfair behavior and, in light of recent
regulations, has attracted the attention of the research community. Several
researchers focused on seeking new fairness definitions or developing
approaches to identify biased predictions. However, none try to exploit the
counterfactual space to this aim. In that direction, the methodology proposed
in this work aims to unveil unfair model behaviors using counterfactual
reasoning in the case of fairness under unawareness setting. A counterfactual
version of equal opportunity named counterfactual fair opportunity is defined
and two novel metrics that analyze the sensitive information of counterfactual
samples are introduced. Experimental results on three different datasets show
the efficacy of our methodologies and our metrics, disclosing the unfair
behavior of classic machine learning and debiasing models
Formalizing Multimedia Recommendation through Multimodal Deep Learning
Recommender systems (RSs) offer personalized navigation experiences on online
platforms, but recommendation remains a challenging task, particularly in
specific scenarios and domains. Multimodality can help tap into richer
information sources and construct more refined user/item profiles for
recommendations. However, existing literature lacks a shared and universal
schema for modeling and solving the recommendation problem through the lens of
multimodality. This work aims to formalize a general multimodal schema for
multimedia recommendation. It provides a comprehensive literature review of
multimodal approaches for multimedia recommendation from the last eight years,
outlines the theoretical foundations of a multimodal pipeline, and demonstrates
its rationale by applying it to selected state-of-the-art approaches. The work
also conducts a benchmarking analysis of recent algorithms for multimedia
recommendation within Elliot, a rigorous framework for evaluating recommender
systems. The main aim is to provide guidelines for designing and implementing
the next generation of multimodal approaches in multimedia recommendation
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