1,720,965 research outputs found
Contrasting Deepfakes Diffusion via Contrastive Learning and Global-Local Similarities
No full textDiscerning between authentic content and that generated by advanced AI methods has become increasingly challenging. While previous research primarily addresses the detection of fake faces, the identification of generated natural images has only recently surfaced. This prompted the recent exploration of solutions that employ foundation vision-and-language models, like CLIP. However, the CLIP embedding space is optimized for global image-to-text alignment and is not inherently designed for deepfake detection, neglecting the potential benefits of tailored training and local image features. In this study, we propose CoDE (Contrastive Deepfake Embeddings), a novel embedding space specifically designed for deepfake detection. CoDE is trained via contrastive learning by additionally enforcing global-local similarities. To sustain the training of our model, we generate a comprehensive dataset that focuses on images generated by diffusion models and encompasses a collection of 9.2 million images produced by using four different generators. Experimental results demonstrate that CoDE achieves state-of-the-art accuracy on the newly collected dataset, while also showing excellent generalization capabilities to unseen image generators. Our source code, trained models, and collected dataset are publicly available at: https://github.com/aimagelab/CoDE
Adapt to Scarcity: Few-Shot Deepfake Detection via Low-Rank Adaptation
Get PDFThe boundary between AI-generated images and real photographs is becoming increasingly narrow, thanks to the realism provided by contemporary generative models. Such technological progress necessitates the evolution of existing deepfake detection algorithms to counter new threats and protect the integrity of perceived reality. Although the prevailing approach among deepfake detection methodologies relies on large collections of generated and real data, the efficacy of these methods in adapting to scenarios characterized by data scarcity remains uncertain. This obstacle arises due to the introduction of novel generation algorithms and proprietary generative models that impose restrictions on access to large-scale datasets, thereby constraining the availability of generated images. In this paper, we first analyze how the performance of current deepfake methodologies, based on the CLIP embedding space, adapt in a few-shot situation over four state-of-the-art generators. Being the CLIP embedding space not specifically tailored for the task, a fine-tuning stage is desirable, although the amount of data needed is often unavailable in a data scarcity scenario. To address this issue and limit possible overfitting, we introduce a novel approach through the Low-Rank Adaptation (LoRA) of the CLIP architecture, tailored for few-shot deepfake detection scenarios. Remarkably, the LoRA-modified CLIP, even when fine-tuned with merely 50 pairs of real and fake images, surpasses the performance of all evaluated deepfake detection models across the tested generators. Additionally, when LoRA CLIP is benchmarked against other models trained on 1,000 samples and evaluated on generative models not seen during training it exhibits superior generalization capabilities
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Benchmarking BERT-based Models for Latin: A Case Study on Biblical References in Ancient Christian Literature
Get PDFTransformer-based language models like BERT have revolutionized Natural Language Processing (NLP) research, but their application to historical languages remains underexplored. This paper investigates the adaptation of BERT-based embedding models for Latin, a language central to the study of the sacred texts of Christianity. Focusing on Jerome’s Vulgate, pre-Vulgate Latin translations of the Bible, and patristic commentaries such as Augustine’s De Genesi ad litteram, we address the challenges posed by Latin’s complex syntax, specialized vocabulary, and historical variations at the orthographic, morphological, and semantic levels. In particular, we propose fine-tuning existing BERT-based embedding models on annotated Latin corpora, using self-generated hard negatives to improve performance in detecting biblical references in early Christian literature in Latin. Experimental results demonstrate the ability of BERT-based models to identify citations of and allusions to the Bible(s) in ancient Christian commentaries while highlighting the complexities and challenges of this field. By integrating NLP techniques with humanistic expertise, this work provides a case study on intertextual analysis in Latin patristic works. It underscores the transformative potential of interdisciplinary approaches, advancing computational tools for sacred text studies and bridging the gap between philology and computational analysis
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Safe-CLIP: Removing NSFW Concepts from Vision-and-Language Models
Get PDFLarge-scale vision-and-language models, such as CLIP, are typically trained on web-scale data, which can introduce inappropriate content and lead to the development of unsafe and biased behavior. This, in turn, hampers their applicability in sensitive and trustworthy contexts and could raise significant concerns in their adoption. Our research introduces a novel approach to enhancing the safety of vision-and-language models by diminishing their sensitivity to NSFW (not safe for work) inputs. In particular, our methodology seeks to sever "toxic" linguistic and visual concepts, unlearning the linkage between unsafe linguistic or visual items and unsafe regions of the embedding space. We show how this can be done by fine-tuning a CLIP model on synthetic data obtained from a large language model trained to convert between safe and unsafe sentences, and a text-to-image generator. We conduct extensive experiments on the resulting embedding space for cross-modal retrieval, text-to-image, and image-to-text generation, where we show that our model can be remarkably employed with pre-trained generative models. Our source code and trained models are available at: https://github.com/aimagelab/safe-clip
Wiki-LLaVA: Hierarchical Retrieval-Augmented Generation for Multimodal LLMs
Get PDFMultimodal LLMs are the natural evolution of LLMs and enlarge their capabilities so as to work beyond the pure textual modality. As research is being carried out to design novel architectures and vision-and-language adapters in this paper we concentrate on endowing such models with the capability of answering questions that require external knowledge. Our approach termed Wiki-LLaVA aims at integrating an external knowledge source of multimodal documents which is accessed through a hierarchical retrieval pipeline. Relevant passages using this approach are retrieved from the external knowledge source and employed as additional context for the LLM augmenting the effectiveness and precision of generated dialogues. We conduct extensive experiments on datasets tailored for visual question answering with external data and demonstrate the appropriateness of our approach
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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