492 research outputs found
Introducing User Feedback-based Counterfactual Explanations (UFCE)
Machine learning models are widely used in real-world applications. However,
their complexity makes it often challenging to interpret the rationale behind
their decisions. Counterfactual explanations (CEs) have emerged as a viable
solution for generating comprehensible explanations in eXplainable Artificial
Intelligence (XAI). CE provides actionable information to users on how to
achieve the desired outcome with minimal modifications to the input. However,
current CE algorithms usually operate within the entire feature space when
optimizing changes to turn over an undesired outcome, overlooking the
identification of key contributors to the outcome and disregarding the
practicality of the suggested changes. In this study, we introduce a novel
methodology, that is named as user feedback-based counterfactual explanation
(UFCE), which addresses these limitations and aims to bolster confidence in the
provided explanations. UFCE allows for the inclusion of user constraints to
determine the smallest modifications in the subset of actionable features while
considering feature dependence, and evaluates the practicality of suggested
changes using benchmark evaluation metrics. We conducted three experiments with
five datasets, demonstrating that UFCE outperforms two well-known CE methods in
terms of \textit{proximity}, \textit{sparsity}, and \textit{feasibility}.
Reported results indicate that user constraints influence the generation of
feasible CEs.Comment: preprint of paper submitted to IJCIS Springe
Spectral emissivity and temperature maps of the Solfatara crater from DAIS hyperspectral images
Quantitative maps of surface temperature and spectral emissivity have been retrieved on the Solfatara crater at Pozzuoli (Naples) from remote sensing hyperspectral data. The present study relies on thermal infrared images collected on July 27, 1997 by the DAIS hyperspectral sensor owned by the German aerospace center (DLR). The Emissivity Spectrum Normalization method was used to make temperature and emissivity estimates. Raw data were previously transformed in radiance and corrected for the atmospheric contributions using the MODTRAN radiative transfer code and the sensor response functions. During the DAIS flight a radiosonde was launched to collect the atmospheric profiles of pressure, temperature and humidity used as input to the code. Retrieved temperature values are in good agreement with temperature measurements performed in situ during the campaign. The spectral emissivity map was used to classify the image in different geo-mineralogical units with the Spectral Angle Mapper method. Areas of geologic interest were previously selected using a mask obtained from an NDVI image calculated with two channels of the visible (red) and the near infrared respectively
Spectral emissivity and temperature maps of the Solfatara crater from DAIS hyperspectral images
Quantitative maps of surface temperature and spectral emissivity have been retrieved on the
Solfatara crater at Pozzuoli (Naples) from remote sensing hyperspectral data. The present study
relies on thermal infrared images collected on July 27, 1997 by the DAIS hyperspectral sensor,
owned by the German aerospace center (DLR). The Emissivity Spectrum Normalization method
was used to make temperature and emissivity estimates. Raw data were previously transformed in
radiance and corrected for the atmospheric contributes using the MODTRAN radiative transfer code
and the sensor response functions. During the DAIS flight a radiosonde was launched to collect the
atmospheric profiles of pressure, temperature and humidity used as input to the code. Retrieved
temperature values are in good agreement with temperature measures performed in situ during the
campaign. The spectral emissivity map was used to classify the image in different geomineralogical
units with the Spectral Angle Mapper method. Areas of geologic interest were
previously selected using a mask obtained from an NDVI image calculated with two channels of the
visible (red) and the near infrared respectively
Toward enriched Cognitive Learning with XAI
As computational systems supported by artificial intelligence (AI) techniques
continue to play an increasingly pivotal role in making high-stakes
recommendations and decisions across various domains, the demand for
explainable AI (XAI) has grown significantly, extending its impact into
cognitive learning research. Providing explanations for novel concepts is
recognised as a fundamental aid in the learning process, particularly when
addressing challenges stemming from knowledge deficiencies and skill
application. Addressing these difficulties involves timely explanations and
guidance throughout the learning process, prompting the interest of AI experts
in developing explainer models. In this paper, we introduce an intelligent
system (CL-XAI) for Cognitive Learning which is supported by XAI, focusing on
two key research objectives: exploring how human learners comprehend the
internal mechanisms of AI models using XAI tools and evaluating the
effectiveness of such tools through human feedback. The use of CL-XAI is
illustrated with a game-inspired virtual use case where learners tackle
combinatorial problems to enhance problem-solving skills and deepen their
understanding of complex concepts, highlighting the potential for
transformative advances in cognitive learning and co-learning.Comment: 10 pages, 2 figure
Direct Measures of Path Delays on Commercial FPGA Chips
We present a general technique for measuring the propagation delay on the internal wires of FPGA chips. The measure is based on the comparison between the operating frequencies of two ring oscillators that differ only for the structure under test, that is included (or not) in the loop. Experimental results are presented for a device of the Xilinx XC4000 family
A Score Index System for a Semi-Quantitative Assessment of Inhalation Risks at Contaminated Sites
Risk assessment of contaminated sites is typically applied following a tiered approach with increasing levels of complexity. In the standard risk-based corrective action (RBCA) procedure issued by the American Society for Testing and Materials (ASTM), the site-specific evaluation is carried out using fate and transport models that require a relatively large amount of input data. In this work, we introduce a site-specific score index system for a preliminary assessment of the inhalation risks related to contaminants in soil or groundwater that resembles the modeling approaches typically adopted for chemical risk assessment in the field of industrial hygiene. In the developed system, a risk index for the outdoor and indoor volatilization pathways is calculated as the ratio between the calculated concentration at the point of exposure for the contaminant of concern and the corresponding acceptable concentration in air. The concentration at the point of exposure for each contaminant of concern is estimated through simple algorithms that involve a limited number of indexes that depend on the parameters that affect the exposure scenario. This qualitative assessment is then converted into a semi-quantitative approach by introducing scaling factors that were calibrated using the ASTM RBCA fate and transport models. The procedure was validated against the standard RBCA procedure by performing a simple Monte Carlo analysis with 10,000 simulations with randomly varying site-specific parameters. The developed score index system resulted in a conservative estimate of the risks, with percentages of false negatives lower than 1% and false positives lower than 15%. This means that the developed system allows one to screen out sites from further evaluations in more than 80% of cases, while ensuring a conservative estimate of the expected risks. The application to a real case study of a contaminated site confirmed the suitability of the developed approach
L’utilizzo delle protesi endoscopiche nella patologia dell’apparato digerente
L’utilizzo di protesi ad introduzione per via endoscopica per patologie dell’apparato digerente sia benigne che maligne ha avuto negli ultimi anni un considerevole sviluppo. Il posizionamento delle endoprotesi è ben tollerato dai pazienti, non necessita di anestesia e comporta rischi relativamente minimi. Le nuove protesi metalliche autoespansibili permettono di risolvere stenosi anche molto serrate senza quasi mai necessità di dilatazione, con riduzione dei rischi che da questa derivano. Viene riportata una revisione dell’esperienza di protesizzazione per patologie dell’apparato digerente e vengono discussi le indicazioni, i limiti e le complicanze, sulla scorta dei dati dalla letteratura internazionale
Analyses of TIMS and AVIRIS data, integrated with field and laboratory spectra, for lithological and mineralogical interpretation of Vulcano Island, Italy
Vulcano Island is part of the Eolian archipelago, located about 25 km from the northeast coast of Sicily. The archipelago comprises seven major volcanic islands, two of which are active volcanoes (Vulcano and Stromboli). Vulcano covers an area of about 50 square km, and is about 10 km long. Explosive volcanic activity has predominated in the geological evolution of Vulcano Island, and there is no evidence that this pattern has ceased. Rather, the current situation is one of unrest, so a strict regimen of continuous geophysical and geochemical monitoring has been undertaken over the last decade. Though the year-round population of Vulcano is small (under 1000), during the summer the island becomes a very popular resort, and has thousands of additional tourists at any time throughout the high season, thus substantially increasing the number of people potentially at risk from an explosive eruption or other hazards such as noxious gas emissions (e.g., CO2, H2S, SO2). During the past ten years, remote sensing data have been repetitively acquired with optical and microwave airborne sensors. The present work shows the preliminary results of a study based on the integration of various remote sensing data sets with field spectroscopy, and other laboratory analyses, for the geological and geomorphological mapping of the island. It is hoped that such work will also usefully contribute to the evaluation of the volcanic hazard potential of the islands as well as to the evaluation of the status of its current activity
The gamma-ray burst monitor for Lobster-ISS
Lobster-ISS is an X-ray all-sky monitor experiment selected by ESA two years
ago for a Phase A study (now almost completed) for a future flight (2009)
aboard the Columbus Exposed Payload Facility of the International Space
Station. The main instrument, based on MCP optics with Lobster-eye geometry,
has an energy passband from 0.1 to 3.5 keV, an unprecedented daily sensitivity
of 2x10^{-12} erg cm^{-2}s$^{-1}, and it is capable to scan, during each orbit,
the entire sky with an angular resolution of 4--6 arcmin. This X-ray telescope
is flanked by a Gamma Ray Burst Monitor, with the minimum requirement of
recognizing true GRBs from other transient events. In this paper we describe
the GRBM. In addition to the minimum requirement, the instrument proposed is
capable to roughly localize GRBs which occur in the Lobster FOV (162x22.5
degrees) and to significantly extend the scientific capabilities of the main
instrument for the study of GRBs and X-ray transients. The combination of the
two instruments will allow an unprecedented spectral coverage (from 0.1 up to
300/700 keV) for a sensitive study of the GRB prompt emission in the passband
where GRBs and X-Ray Flashes emit most of their energy. The low-energy spectral
band (0.1-10 keV) is of key importance for the study of the GRB environment and
the search of transient absorption and emission features from GRBs, both goals
being crucial for unveiling the GRB phenomenon. The entire energy band of
Lobster-ISS is not covered by either the Swift satellite or other GRB missions
foreseen in the next decade.Comment: 6 pages, 4 figures. Paper presented at the COSPAR 2004 General
Assembly (Paris), accepted for publication in Advances in Space Research in
June 2005 and available on-line at the Journal site
(http://www.sciencedirect.com/science/journal/02731177), section "Articles in
press
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