New approaches for content-based analysis towards online social network spam detection

Unsolicited email campaigns remain as one of the biggest threats affecting millions of users per day. Although spam filtering techniques are capable of detecting significant percentage of the spam messages, the problem is far from being solved, specially due to the total amount of spam traffic that flows over the Internet, and new potential attack vectors used by malicious users. The deeply entrenched use of Online Social Networks (OSNs), where millions of users share unconsciously any kind of personal data, offers a very attractive channel to attackers. Those sites provide two main interesting areas for malicious activities: exploitation of the huge amount of information stored in the profiles of the users, and the possibility of targeting user addresses and user spaces through their personal profiles, groups, pages... Consequently, new type of targeted attacks are being detected in those communication means. Being selling products, creating social alarm, creating public awareness campaigns, generating traffic with viral contents, fooling users with suspicious attachments, etc. the main purpose of spam messages, those type of communications have a specific writing style that spam filtering can take advantage of. The main objectives of this thesis are: (i) to demonstrate that it is possible to develop new targeted attacks exploiting personalized spam campaigns using OSN information, and (ii) to design and validate novel spam detection methods that help detecting the intentionality of the messages, using natural language processing techniques, in order to classify them as spam or legitimate. Additionally, those methods must be effective also dealing with the spam that is appearing in OSNs. To achieve the first objective a system to design and send personalized spam campaigns is proposed. We extract automatically users’ public information from a well known social site. We analyze it and design different templates taking into account the preferences of the users. After that, different experiments are carried out sending typical and personalized spam. The results show that the click-through rate is considerably improved with this new strategy. In the second part of the thesis we propose three novel spam filtering methods. Those methods aim to detect non-evident illegitimate intent in order to add valid information that is used by spam classifiers. To detect the intentionality of the texts, we hypothesize that sentiment analysis and personality recognition techniques could provide new means to differentiate spam text from legitimate one. Taking into account this assumption, we present three different methods: the first one uses sentiment analysis to extract the polarity feature of each analyzed text, thus we analyze the optimistic or pessimistic attitude of spam messages compared to legitimate texts. The second one uses personality recognition techniques to add personality dimensions (Extroversion/Introversion, Thinking/Feeling, Judging/ Perceiving and Sensing/iNtuition) to the spam filtering process; and the last one is a combination of the two previously mentioned techniques. Once the methods are described, we experimentally validate the proposed approaches in three different types of spam: email spam, SMS spam and spam from a popular OSN.Hartzailearen baimenik gabe bidalitako mezuak (spam) egunean milioika erabiltzaileri eragiten dien mehatxua dira. Nahiz eta spam detekzio tresnek gero eta emaitza hobeagoak lortu, arazoa konpontzetik oso urruti dago oraindik, batez ere spam kopuruari eta erasotzaileen estrategia berriei esker. Hori gutxi ez eta azken urteetan sare sozialek izan duten erabiltzaile gorakadaren ondorioz, non milioika erabiltzailek beraien datu pribatuak publiko egiten dituzten, gune hauek oso leku erakargarriak bilakatu dira erasotzaileentzat. Batez ere bi arlo interesgarri eskaintzen dituzte webgune hauek: profiletan pilatutako informazio guztiaren ustiapena, eta erabiltzaileekin harreman zuzena izateko erraztasuna (profil bidez, talde bidez, orrialde bidez...). Ondorioz, gero eta ekintza ilegal gehiago atzematen ari dira webgune hauetan. Spam mezuen helburu nagusienak zerbait saldu, alarma soziala sortu, sentsibilizazio kanpainak martxan jarri, etab. izaki, mezu mota hauek eduki ohi duten idazketa mezua berauen detekziorako erabilia izan daiteke. Lan honen helburu nagusiak ondorengoak dira: alde batetik, sare sozialetako informazio publikoa erabiliz egungo detekzio sistemak saihestuko dituen spam pertsonalizatua garatzea posible dela erakustea; eta bestetik hizkuntza naturalaren prozesamendurako teknikak erabiliz, testuen intentzionalitatea atzeman eta spam-a detektatzeko metodologia berriak garatzea. Gainera, sistema horiek sare sozialetako spam mezuekin lan egiteko gaitasuna ere izan beharko dute. Lehen helburu hori lortzekolan honetan spam pertsonalizatua diseinatu eta bidaltzeko sistema bat aurkeztu da. Era automatikoan erabiltzaileen informazio publikoa ateratzen dugu sare sozial ospetsu batetik, ondoren informazio hori aztertu eta txantiloi ezberdinak garatzen ditugu erabiltzaileen iritziak kontuan hartuaz. Behin hori egindakoan, hainbat esperimentu burutzen ditugu spam normala eta pertsonalizatua bidaliz, bien arteko emaitzen ezberdintasuna alderatzeko. Tesiaren bigarren zatian hiru spam atzemate metodologia berri aurkezten ditugu. Berauen helburua tribialak ez den intentzio komertziala atzeman ta hori baliatuz spam mezuak sailkatzean datza. Intentzionalitate hori lortze aldera, analisi sentimentala eta pertsonalitate detekzio teknikak erabiltzen ditugu. Modu honetan, hiru sistema ezberdin aurkezten dira hemen: lehenengoa analisi sentimentala soilik erabiliz, bigarrena lan honetarako pertsonalitate detekzio teknikek eskaintzen dutena aztertzen duena, eta azkenik, bien arteko konbinazioa. Tresna hauek erabiliz, balidazio esperimentala burutzen da proposatutako sistemak eraginkorrak diren edo ez aztertzeko, hiru mota ezberdinetako spam-arekin lan eginez: email spam-a, SMS spam-a eta sare sozial ospetsu bateko spam-a

Knowledge Modelling and Learning through Cognitive Networks

One of the most promising developments in modelling knowledge is cognitive network science, which aims to investigate cognitive phenomena driven by the networked, associative organization of knowledge. For example, investigating the structure of semantic memory via semantic networks has illuminated how memory recall patterns influence phenomena such as creativity, memory search, learning, and more generally, knowledge acquisition, exploration, and exploitation. In parallel, neural network models for artificial intelligence (AI) are also becoming more widespread as inferential models for understanding which features drive language-related phenomena such as meaning reconstruction, stance detection, and emotional profiling. Whereas cognitive networks map explicitly which entities engage in associative relationships, neural networks perform an implicit mapping of correlations in cognitive data as weights, obtained after training over labelled data and whose interpretation is not immediately evident to the experimenter. This book aims to bring together quantitative, innovative research that focuses on modelling knowledge through cognitive and neural networks to gain insight into mechanisms driving cognitive processes related to knowledge structuring, exploration, and learning. The book comprises a variety of publication types, including reviews and theoretical papers, empirical research, computational modelling, and big data analysis. All papers here share a commonality: they demonstrate how the application of network science and AI can extend and broaden cognitive science in ways that traditional approaches cannot

Design of an E-learning system using semantic information and cloud computing technologies

Humanity is currently suffering from many difficult problems that threaten the life and survival of the human race. It is very easy for all mankind to be affected, directly or indirectly, by these problems. Education is a key solution for most of them. In our thesis we tried to make use of current technologies to enhance and ease the learning process. We have designed an e-learning system based on semantic information and cloud computing, in addition to many other technologies that contribute to improving the educational process and raising the level of students. The design was built after much research on useful technology, its types, and examples of actual systems that were previously discussed by other researchers. In addition to the proposed design, an algorithm was implemented to identify topics found in large textual educational resources. It was tested and proved to be efficient against other methods. The algorithm has the ability of extracting the main topics from textual learning resources, linking related resources and generating interactive dynamic knowledge graphs. This algorithm accurately and efficiently accomplishes those tasks even for bigger books. We used Wikipedia Miner, TextRank, and Gensim within our algorithm. Our algorithm‘s accuracy was evaluated against Gensim, largely improving its accuracy. Augmenting the system design with the implemented algorithm will produce many useful services for improving the learning process such as: identifying main topics of big textual learning resources automatically and connecting them to other well defined concepts from Wikipedia, enriching current learning resources with semantic information from external sources, providing student with browsable dynamic interactive knowledge graphs, and making use of learning groups to encourage students to share their learning experiences and feedback with other learners.Programa de Doctorado en Ingeniería Telemática por la Universidad Carlos III de MadridPresidente: Luis Sánchez Fernández.- Secretario: Luis de la Fuente Valentín.- Vocal: Norberto Fernández Garcí

Hybrid human-AI driven open personalized education

Attaining those skills that match labor market demand is getting increasingly complicated as prerequisite knowledge, skills, and abilities are evolving dynamically through an uncontrollable and seemingly unpredictable process. Furthermore, people's interests in gaining knowledge pertaining to their personal life (e.g., hobbies and life-hacks) are also increasing dramatically in recent decades. In this situation, anticipating and addressing the learning needs are fundamental challenges to twenty-first century education. The need for such technologies has escalated due to the COVID-19 pandemic, where online education became a key player in all types of training programs. The burgeoning availability of data, not only on the demand side but also on the supply side (in the form of open/free educational resources) coupled with smart technologies, may provide a fertile ground for addressing this challenge. Therefore, this thesis aims to contribute to the literature about the utilization of (open and free-online) educational resources toward goal-driven personalized informal learning, by developing a novel Human-AI based system, called eDoer. In this thesis, we discuss all the new knowledge that was created in order to complete the system development, which includes 1) prototype development and qualitative user validation, 2) decomposing the preliminary requirements into meaningful components, 3) implementation and validation of each component, and 4) a final requirement analysis followed by combining the implemented components in order develop and validate the planned system (eDoer). All in all, our proposed system 1) derives the skill requirements for a wide range of occupations (as skills and jobs are typical goals in informal learning) through an analysis of online job vacancy announcements, 2) decomposes skills into learning topics, 3) collects a variety of open/free online educational resources that address those topics, 4) checks the quality of those resources and topic relevance using our developed intelligent prediction models, 5) helps learners to set their learning goals, 6) recommends personalized learning pathways and learning content based on individual learning goals, and 7) provides assessment services for learners to monitor their progress towards their desired learning objectives. Accordingly, we created a learning dashboard focusing on three Data Science related jobs and conducted an initial validation of eDoer through a randomized experiment. Controlling for the effects of prior knowledge as assessed by the pretest, the randomized experiment provided tentative support for the hypothesis that learners who engaged with personal eDoer recommendations attain higher scores on the posttest than those who did not. The hypothesis that learners who received personalized content in terms of format, length, level of detail, and content type, would achieve higher scores than those receiving non-personalized content was not supported as a statistically significant result

Low-cost methodologies and devices applied to measure, model and self-regulate emotions for Human-Computer Interaction

En aquesta tesi s'exploren les diferents metodologies d'anàlisi de l'experiència UX des d'una visió centrada en usuari. Aquestes metodologies clàssiques i fonamentades només permeten extreure dades cognitives, és a dir les dades que l'usuari és capaç de comunicar de manera conscient. L'objectiu de la tesi és proposar un model basat en l'extracció de dades biomètriques per complementar amb dades emotives (i formals) la informació cognitiva abans esmentada. Aquesta tesi no és només teòrica, ja que juntament amb el model proposat (i la seva evolució) es mostren les diferents proves, validacions i investigacions en què s'han aplicat, sovint en conjunt amb grups de recerca d'altres àrees amb èxit.En esta tesis se exploran las diferentes metodologías de análisis de la experiencia UX desde una visión centrada en usuario. Estas metodologías clásicas y fundamentadas solamente permiten extraer datos cognitivos, es decir los datos que el usuario es capaz de comunicar de manera consciente. El objetivo de la tesis es proponer un modelo basado en la extracción de datos biométricos para complementar con datos emotivos (y formales) la información cognitiva antes mencionada. Esta tesis no es solamente teórica, ya que junto con el modelo propuesto (y su evolución) se muestran las diferentes pruebas, validaciones e investigaciones en la que se han aplicado, a menudo en conjunto con grupos de investigación de otras áreas con éxito.In this thesis, the different methodologies for analyzing the UX experience are explored from a user-centered perspective. These classical and well-founded methodologies only allow the extraction of cognitive data, that is, the data that the user is capable of consciously communicating. The objective of this thesis is to propose a methodology that uses the extraction of biometric data to complement the aforementioned cognitive information with emotional (and formal) data. This thesis is not only theoretical, since the proposed model (and its evolution) is complemented with the different tests, validations and investigations in which they have been applied, often in conjunction with research groups from other areas with success

Online failure prediction in air traffic control systems

This thesis introduces a novel approach to online failure prediction for mission critical distributed systems that has the distinctive features to be black-box, non-intrusive and online. The approach combines Complex Event Processing (CEP) and Hidden Markov Models (HMM) so as to analyze symptoms of failures that might occur in the form of anomalous conditions of performance metrics identified for such purpose. The thesis presents an architecture named CASPER, based on CEP and HMM, that relies on sniffed information from the communication network of a mission critical system, only, for predicting anomalies that can lead to software failures. An instance of Casper has been implemented, trained and tuned to monitor a real Air Traffic Control (ATC) system developed by Selex ES, a Finmeccanica Company. An extensive experimental evaluation of CASPER is presented. The obtained results show (i) a very low percentage of false positives over both normal and under stress conditions, and (ii) a sufficiently high failure prediction time that allows the system to apply appropriate recovery procedures

Linked Open Data - Creating Knowledge Out of Interlinked Data: Results of the LOD2 Project

Database Management; Artificial Intelligence (incl. Robotics); Information Systems and Communication Servic