1,688 research outputs found
Validating Multimedia Content Moderation Software via Semantic Fusion
The exponential growth of social media platforms, such as Facebook and
TikTok, has revolutionized communication and content publication in human
society. Users on these platforms can publish multimedia content that delivers
information via the combination of text, audio, images, and video. Meanwhile,
the multimedia content release facility has been increasingly exploited to
propagate toxic content, such as hate speech, malicious advertisements, and
pornography. To this end, content moderation software has been widely deployed
on these platforms to detect and blocks toxic content. However, due to the
complexity of content moderation models and the difficulty of understanding
information across multiple modalities, existing content moderation software
can fail to detect toxic content, which often leads to extremely negative
impacts.
We introduce Semantic Fusion, a general, effective methodology for validating
multimedia content moderation software. Our key idea is to fuse two or more
existing single-modal inputs (e.g., a textual sentence and an image) into a new
input that combines the semantics of its ancestors in a novel manner and has
toxic nature by construction. This fused input is then used for validating
multimedia content moderation software. We realized Semantic Fusion as DUO, a
practical content moderation software testing tool. In our evaluation, we
employ DUO to test five commercial content moderation software and two
state-of-the-art models against three kinds of toxic content. The results show
that DUO achieves up to 100% error finding rate (EFR) when testing moderation
software. In addition, we leverage the test cases generated by DUO to retrain
the two models we explored, which largely improves model robustness while
maintaining the accuracy on the original test set.Comment: Accepted by ISSTA 202
Detecção de pornografia em vídeos através de técnicas de aprendizado profundo e informações de movimento
Orientadores: Anderson de Rezende Rocha, Vanessa TestoniDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: Com o crescimento exponencial de gravações em vídeos disponíveis online, a moderação manual de conteúdos sensíveis, e.g, pornografia, violência e multidões, se tornou impra- ticável, aumentando a necessidade de uma filtragem automatizada. Nesta linha, muitos trabalhos exploraram o problema de detecção de pornografia, usando abordagens que vão desde a detecção de pele e nudez, até o uso de características locais e sacola de pala- vras visuais. Contudo, essas técnicas sofrem com casos ambíguos (e.g., cenas em praia, luta livre), produzindo muitos falsos positivos. Isto está possivelmente relacionado com o fato de que essas abordagens estão desatualizadas, e de que poucos autores usaram a informação de movimento presente nos vídeos, que pode ser crucial para a desambi- guação visual dos casos mencionados. Indo adiante para superar estas questões, neste trabalho, nós exploramos soluções de aprendizado em profundidade para o problema de detecção de pornografia em vídeos, levando em consideração tanto a informação está- tica, quanto a informação de movimento disponível em cada vídeo em questão. Quando combinamos as características estáticas e de movimento, o método proposto supera as soluções existentes na literatura. Apesar de as abordagens de aprendizado em profun- didade, mais especificamente as Redes Neurais Convolucionais (RNC), terem alcançado resultados impressionantes em outros problemas de visão computacional, este método tão promissor ainda não foi explorado suficientemente no problema detecção de pornografia, principalmente no que tange à incorporação de informações de movimento presente no vídeo. Adicionalmente, propomos novas formas de combinar as informações estáticas e de movimento usando RNCs, que ainda não foram exploradas para detecção de pornografia, nem em outras tarefas de reconhecimento de ações. Mais especificamente, nós exploramos duas fontes distintas de informação de movimento: Campos de deslocamento de Fluxo Óptico, que tem sido tradicionalmente usados para classificação de vídeos; e Vetores de Movimento MPEG. Embora Vetores de Movimento já tenham sido utilizados pela litera- tura na tarefa de detecção de pornografia, neste trabalho nós os adaptamos, criando uma representação visual apropriada, antes de passá-los a uma rede neural convolucional para aprendizado e extração de características. Nossos experimentos mostraram que, apesar de a técnica de Vetores de Movimento MPEG possuir uma performance inferior quando utilizada de forma isolada, quando comparada à técnica baseada em Fluxo Óptico, ela consegue uma performance similar ao complementar a informação estática, com a van- tagem de estar presente, por construção, nos vídeos, enquanto se decodifica os frames, evitando a necessidade da computação mais cara do Fluxo Óptico. Nossa melhor aborda- gem proposta supera os métodos existentes na literatura em diferentes datasets. Para o dataset Pornography 800, o método consegue uma acurácia de classificação de 97,9%, uma redução do erro de 64,4% quando comparado com o estado da arte (94,1% de acu- rácia neste dataset). Quando consideramos o dataset Pornography 2k, mais desafiador, nosso melhor método consegue um acurácia de 96,4%, reduzindo o erro de classificação em 14,3% em comparação ao estado da arte (95,8%)Abstract: With the exponential growth of video footage available online, human manual moderation of sensitive scenes, e.g., pornography, violence and crowd, became infeasible, increasing the necessity for automated filtering. In this vein, a great number of works has explored the pornographic detection problem, using approaches ranging from skin and nudity de- tection, to local features and bag of visual words. Yet, these techniques suffer from some ambiguous cases (e.g., beach scenes, wrestling), producing too much false positives. This is possibly related to the fact that these approaches are somewhat outdated, and that few authors have used the motion information present in videos, which could be crucial for the visual disambiguation of these cases. Setting forth to overcome these issues, in this work, we explore deep learning solutions to the problem of pornography detection in videos, tak- ing into account both the static and the motion information available for each questioned video. When incorporating the static and motion complementary features, the proposed method outperforms the existing solutions in the literature. Although Deep Learning ap- proaches, more specifically Convolutional Neural Networks (CNNs), have achieved striking results on other vision-related problems, such promising methods are still not sufficiently explored in pornography detection while incorporating motion information. We also pro- pose novel ways for combining the static and the motion information using CNNs, that have not been explored in pornography detection, nor in other action recognition tasks before. More specifically, we explore two distinct sources of motion information herein: Optical Flow displacement fields, which have been traditionally used for video classifica- tion; and MPEG Motion Vectors. Although Motion Vectors have already been used for pornography detection tasks in the literature, in this work, we adapt them, by finding an appropriate visual representation, before feeding a convolution neural network for feature learning and extraction. Our experiments show that although the MPEG Motion Vectors technique has an inferior performance by itself, than when using its Optical Flow coun- terpart, it yields a similar performance when complementing the static information, with the advantage of being present, by construction, in the video while decoding the frames, avoiding the need for the more expensive Optical Flow calculations. Our best approach outperforms existing methods in the literature when considering different datasets. For the Pornography 800 dataset, it yields a classification accuracy of 97.9%, an error re- duction of 64.4% when compared to the state of the art (94.1% in this dataset). Finally, considering the more challenging Pornography 2k dataset, our best method yields a clas- sification accuracy of 96.4%, reducing the classification error in 14.3% when compared to the state of the art (95.8% in the same dataset)MestradoCiência da ComputaçãoMestre em Ciência da ComputaçãoFuncampCAPE
A Domain Specific Language for Digital Forensics and Incident Response Analysis
One of the longstanding conceptual problems in digital forensics is the dichotomy between the need for verifiable and reproducible forensic investigations, and the lack of practical mechanisms to accomplish them. With nearly four decades of professional digital forensic practice, investigator notes are still the primary source of reproducibility information, and much of it is tied to the functions of specific, often proprietary, tools.
The lack of a formal means of specification for digital forensic operations results in three major problems. Specifically, there is a critical lack of:
a) standardized and automated means to scientifically verify accuracy of digital forensic tools;
b) methods to reliably reproduce forensic computations (their results); and
c) framework for inter-operability among forensic tools.
Additionally, there is no standardized means for communicating software requirements between users, researchers and developers, resulting in a mismatch in expectations. Combined with the exponential growth in data volume and complexity of applications and systems to be investigated, all of these concerns result in major case backlogs and inherently reduce the reliability of the digital forensic analyses.
This work proposes a new approach to the specification of forensic computations, such that the above concerns can be addressed on a scientific basis with a new domain specific language (DSL) called nugget. DSLs are specialized languages that aim to address the concerns of particular domains by providing practical abstractions. Successful DSLs, such as SQL, can transform an application domain by providing a standardized way for users to communicate what they need without specifying how the computation should be performed.
This is the first effort to build a DSL for (digital) forensic computations with the following research goals:
1) provide an intuitive formal specification language that covers core types of forensic computations and common data types;
2) provide a mechanism to extend the language that can incorporate arbitrary computations;
3) provide a prototype execution environment that allows the fully automatic execution of the computation;
4) provide a complete, formal, and auditable log of computations that can be used to reproduce an investigation;
5) demonstrate cloud-ready processing that can match the growth in data volumes and complexity
Crowdsourcing subjective annotations using pairwise comparisons reduces bias and error compared to the majority-vote method
How to better reduce measurement variability and bias introduced by
subjectivity in crowdsourced labelling remains an open question. We introduce a
theoretical framework for understanding how random error and measurement bias
enter into crowdsourced annotations of subjective constructs. We then propose a
pipeline that combines pairwise comparison labelling with Elo scoring, and
demonstrate that it outperforms the ubiquitous majority-voting method in
reducing both types of measurement error. To assess the performance of the
labelling approaches, we constructed an agent-based model of crowdsourced
labelling that lets us introduce different types of subjectivity into the
tasks. We find that under most conditions with task subjectivity, the
comparison approach produced higher scores. Further, the comparison
approach is less susceptible to inflating bias, which majority voting tends to
do. To facilitate applications, we show with simulated and real-world data that
the number of required random comparisons for the same classification accuracy
scales log-linearly with the number of labelled items. We also
implemented the Elo system as an open-source Python package.Comment: Accepted for publication at ACM CSCW 202
CHORUS Deliverable 2.2: Second report - identification of multi-disciplinary key issues for gap analysis toward EU multimedia search engines roadmap
After addressing the state-of-the-art during the first year of Chorus and establishing the existing landscape in
multimedia search engines, we have identified and analyzed gaps within European research effort during our second year.
In this period we focused on three directions, notably technological issues, user-centred issues and use-cases and socio-
economic and legal aspects. These were assessed by two central studies: firstly, a concerted vision of functional breakdown
of generic multimedia search engine, and secondly, a representative use-cases descriptions with the related discussion on
requirement for technological challenges. Both studies have been carried out in cooperation and consultation with the
community at large through EC concertation meetings (multimedia search engines cluster), several meetings with our
Think-Tank, presentations in international conferences, and surveys addressed to EU projects coordinators as well as
National initiatives coordinators. Based on the obtained feedback we identified two types of gaps, namely core
technological gaps that involve research challenges, and “enablers”, which are not necessarily technical research
challenges, but have impact on innovation progress. New socio-economic trends are presented as well as emerging legal
challenges
Data-Centric Governance
Artificial intelligence (AI) governance is the body of standards and
practices used to ensure that AI systems are deployed responsibly. Current AI
governance approaches consist mainly of manual review and documentation
processes. While such reviews are necessary for many systems, they are not
sufficient to systematically address all potential harms, as they do not
operationalize governance requirements for system engineering, behavior, and
outcomes in a way that facilitates rigorous and reproducible evaluation. Modern
AI systems are data-centric: they act on data, produce data, and are built
through data engineering. The assurance of governance requirements must also be
carried out in terms of data. This work explores the systematization of
governance requirements via datasets and algorithmic evaluations. When applied
throughout the product lifecycle, data-centric governance decreases time to
deployment, increases solution quality, decreases deployment risks, and places
the system in a continuous state of assured compliance with governance
requirements.Comment: 26 pages, 13 figure
2016 Armstrong Student Scholar Symposium Oral Presentations Abstracts
2006 Armstrong Student Scholar Symposium Oral Presentations Abstract
Recent Advances in Social Data and Artificial Intelligence 2019
The importance and usefulness of subjects and topics involving social data and artificial intelligence are becoming widely recognized. This book contains invited review, expository, and original research articles dealing with, and presenting state-of-the-art accounts pf, the recent advances in the subjects of social data and artificial intelligence, and potentially their links to Cyberspace
Department of Computer Science Activity 1998-2004
This report summarizes much of the research and teaching activity of the Department of Computer Science at Dartmouth College between late 1998 and late 2004. The material for this report was collected as part of the final report for NSF Institutional Infrastructure award EIA-9802068, which funded equipment and technical staff during that six-year period. This equipment and staff supported essentially all of the department\u27s research activity during that period
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