283 research outputs found
Soft biometrics and their application in person recognition at a distance
Get PDFSoft biometric information extracted from a human body (e.g., height, gender, skin color, hair color, and so on) is ancillary information easily distinguished at a distance but it is not fully distinctive by itself in recognition tasks. However, this soft information can be explicitly fused with biometric recognition systems to improve the overall recognition when confronting high variability conditions. One significant example is visual surveillance, where face images are usually captured in poor quality conditions with high variability and automatic face recognition systems do not work properly. In this scenario, the soft biometric information can provide very valuable information for person recognition. This paper presents an experimental study of the benefits of soft biometric labels as ancillary information based on the description of human physical features to improve challenging person recognition scenarios at a distance. In addition, we analyze the available soft biometric information in scenarios of varying distance between camera and subject. Experimental results based on the Southampton multibiometric tunnel database show that the use of soft biometric traits is able to improve the performance of face recognition based on sparse representation on real and ideal scenarios by adaptive fusion rules
TypeFormer: transformers for mobile keystroke biometrics
No full textThe broad usage of mobile devices nowadays, the sensitiveness of the information contained in them, and the shortcomings of current mobile user authentication methods are calling for novel, secure, and unobtrusive solutions to verify the users’ identity. In this article, we propose TypeFormer, a novel transformer architecture to model free-text keystroke dynamics performed on mobile devices for the purpose of user authentication. The proposed model consists in temporal and channel modules enclosing two long short-term memory recurrent layers, Gaussian range encoding, a multi-head self-attention mechanism, and a block-recurrent transformer layer. Experimenting on one of the largest public databases to date, the Aalto mobile keystroke database, TypeFormer outperforms current state-of-the-art systems achieving equal error rate values of 3.25% using only five enrolment sessions of 50 keystrokes each. In such way, we contribute to reducing the traditional performance gap of the challenging mobile free-text scenario with respect to its desktop and fixed-text counterparts. To highlight the design rationale, an analysis of the experimental results of the different modules implemented in the development of TypeFormer is carried out. Additionally, we analyse the behaviour of the model with different experimental configurations such as the length of the keystroke sequences and the amount of enrolment sessions, showing margin for improvement.</p
Complexity-based biometric signature verification
No full textOn-line signature verification systems are mainly based on two approaches: feature- or time functions-based systems (a.k.a. global and local systems). However, new sources of information can be also considered in order to complement these traditional approaches, reduce the intra-class variability and achieve more robust signature verification systems against forgers. In this paper we focus on the use of the concept of complexity in on-line signature verification systems. The main contributions of the present work are: 1) classification of users according to the complexity level of their signatures using features extracted from the Sigma LogNormal writing generation model, and 2) a new architecture for signature verification exploiting signature complexity that results in highly improved performance. Our proposed approach is tested considering the BiosecurID on-line signature database with a total of 400 users. Results of 5.8.0 an analysis of the optimal time functions for each complexity level is performed providing practical insights for the application of signature verification in real scenarios
Detection of AI-Generated Synthetic Faces
No full textIn recent years there have been astonishing advances in AI-based synthetic media generation. Thanks to deep learning methods it is now possible to generate visual data with a high level of realism. This is especially true for human faces. Advanced deep learning tools allow one to easily change some specific attributes of a real face or even create brand new identities. Although this opens up a large number of new opportunities, just think of the entertainment industry, it also undermines the trustworthiness of media content and supports the spread of fake identities over the internet. In this context, there is a fundamental need to develop robust and automatic tools capable of distinguishing synthetic faces from real ones. The scientific community is making a huge research effort in this field, proposing several interesting approaches. However, a universal detector is yet to come. Fundamentally, the research in this field is like a cat and mouse game, with new detectors that are designed to deal with powerful synthetic face generators, while the latter keep improving to produce more and more realistic images. In this chapter we will present the most effective techniques proposed in the literature for the detection of synthetic faces. We will analyze their rationale, present real-world application scenarios, and compare different approaches in terms of accuracy and generalization ability
The symbols in the poetry of ruben dario
No full text碩士本論文主要分為三個章節，第一章，何為象徵符號？本章節主要藉由象徵理論學家，威爾伯 (Wilbur Marshall Urban)、弗萊(Northrop Frye)、托多羅夫(Tzvetan Todorov)、賽洛特(Juan-Eduardo Cirlot)以及其他學者的相關文獻解釋象徵符號的定義以及象徵符號在文學作品中的定義。
第二章針對達里歐的生平、作品以及達里歐在現實主義時期的重要性為論述重點。筆者根據達里歐的生平以及生長年代來了解他的作品特色，達里歐一生多采多姿，尤其感情方面更為豐富，這些人生際遇皆影響達里歐的寫作風格。達里歐不只是詩人，也是歷史的見證者，從他的作品中可以看到政治歷史的變化趨勢。達里歐著作極為豐富，筆者在本章節挑選三本可以代表達里歐的作品：《藍》(Azul)、《每日詩》(Prosas profanes)以及《生命與希望之歌》(Cantos de vida y esperanza)。達里歐與現實主義有著密不可分的關係，他的寫作風格不僅受到現實主義作家的影響，同時也是影響現實主義作家的重要人士之一。
第三章筆者不僅針對達里歐的詩集作品分析，同時也分析其散文作品，如《稀奇》(Los raros)。筆者將經常出現於達里歐作品中的象徵符號分為三個部分：顏色符號、禽鳥符號和寶石符號。顏色符號部分主要分析的顏色為藍色、綠色、白色以及黑色。禽鳥符號則針對天鵝、鴿子、孔雀和老鷹。而最後的寶石符號則以珠寶、寶石、鑽石、琥珀、黃金和水晶為主要分析內容。
最後筆者希望藉由這篇論文的研究，能讓大家了解象徵符號經由作家的詮釋，即使相同的符號，也擁有不同的意義。此外也希望大家能透過此篇論文認識文學史上重要的拉丁美洲作家盧本達里歐先生。In this thesis we explore definitions of symbols and the life of the author in the book of Ruben Dario. Dario is an author who emphasized the importance of the use of symbols though out his books. Therefore we might consider him as a master specialized in writing with symbols.
We divide the thesis into three chapters. In the first chapter, we give details to the definition of the symbols. According to scholars like Urban, Frye, Todorov and Cirlot, we are able to understand symbols in forms of signs, images and words. The concept of the symbols is relatively comprehensive, taking into consideration that a symbol is not always a sign; in fact, it is much more than a sign.
In the second chapter, we describe Ruben Dario about his life, literary works and the times when he lived. His life was interesting, colorful and varied. He was not only a poet but a public figure, having been an ambassador of Nicaragua in Spain. Dario wrote many pieces and each was important to him. Based on his narration, there are three books that can represent Ruben Dario, Azul, Prosas profanas and Cantos de vida y esperanza.
Dario was the master of Modernism, mainly because of the great influence of Latin America. Not only did Ruben Dario influence the poets of Modernism but was influenced by other poets in the same period.
In the last chapter we examine the symbols in the poetry of Dario and we divided the symbols into three parts: the colors, birds and precious stones. The first part, we examine the colors. There are blue, green, and black. In the second part, we deal with the symbols of birds, including swans, pigeons, peacocks and eagles. And in the last part, we talk about precious stones. We analyze the symbols of agate, ruby, diamond, crystal and gold. Finally, we end up with the conclusions and bibliography.INTRODUCCION 1
Motivo y objetivo 1
Metodologia de trabajo 3
CAPITULO I: ¿QUE SON LOS SIMBOLOS? 5
1.1 Teorias del simbolo 6
1.2 Los simbolos en la literatura 15
CAPITULO II: RUBEN DARIO Y SU OBRA POETICA 22
2.1 Vida 22
2.2 Obra literaria 28
2.3 Ruben Dario y el Modernismo 35
CAPITULO III: LOS SIMBOLOS EN LA POESIA DE RUBEN DARIO 40
3.1 Colores 40
3.2 Aves 45
3.3 Piedras preciosas 59
CONCLUSION 72
BIBLIOGRAFIA 77
ANEXOS 83學號: 698120028, 學年度: 10
A Survey of Privacy Vulnerabilities of Mobile Device Sensors
Get PDFThe number of mobile devices, such as smartphones and smartwatches, is
relentlessly increasing to almost 6.8 billion by 2022, and along with it, the
amount of personal and sensitive data captured by them. This survey overviews
the state of the art of what personal and sensitive user attributes can be
extracted from mobile device sensors, emphasising critical aspects such as
demographics, health and body features, activity and behaviour recognition,
etc. In addition, we review popular metrics in the literature to quantify the
degree of privacy, and discuss powerful privacy methods to protect the
sensitive data while preserving data utility for analysis. Finally, open
research questions a represented for further advancements in the field
M-GaitFormer: Mobile biometric gait verification using Transformers
Get PDFMobile devices such as smartphones and smartwatches are part of our everyday life, acquiring large amount of personal information that needs to be properly secured. Among the different authentication techniques, behavioural biometrics has become a very popular method as it allows authentication in a non-intrusive and continuous way. This study proposes M-GaitFormer, a novel mobile biometric gait verification system based on Transformer architectures. This biometric system only considers the accelerometer and gyroscope data acquired by the mobile device. A complete analysis of the proposed M-GaitFormer is carried out using the popular available databases whuGAIT and OU-ISIR. M-GaitFormer achieves Equal Error Rate (EER) values of 3.42% and 2.90% on whuGAIT and OU-ISIR, respectively, outperforming other state-of-the-art approaches based on popular Convolutional Neural Networks (CNNs) and Recurrent Neural Networks (RNNs)
Exploring Transformers for Behavioural Biometrics: A Case Study in Gait Recognition
Get PDFBiometrics on mobile devices has attracted a lot of attention in recent years
as it is considered a user-friendly authentication method. This interest has
also been motivated by the success of Deep Learning (DL). Architectures based
on Convolutional Neural Networks (CNNs) and Recurrent Neural Networks (RNNs)
have been established to be convenient for the task, improving the performance
and robustness in comparison to traditional machine learning techniques.
However, some aspects must still be revisited and improved. To the best of our
knowledge, this is the first article that intends to explore and propose novel
gait biometric recognition systems based on Transformers, which currently
obtain state-of-the-art performance in many applications. Several
state-of-the-art architectures (Vanilla, Informer, Autoformer, Block-Recurrent
Transformer, and THAT) are considered in the experimental framework. In
addition, new configurations of the Transformers are proposed to further
increase the performance. Experiments are carried out using the two popular
public databases whuGAIT and OU-ISIR. The results achieved prove the high
ability of the proposed Transformer, outperforming state-of-the-art CNN and RNN
architectures
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