1,727 research outputs found

    Undergraduate Catalog of Studies, 2023-2024

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    Undergraduate Catalog of Studies, 2023-2024

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    The Application of Data Analytics Technologies for the Predictive Maintenance of Industrial Facilities in Internet of Things (IoT) Environments

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    In industrial production environments, the maintenance of equipment has a decisive influence on costs and on the plannability of production capacities. In particular, unplanned failures during production times cause high costs, unplanned downtimes and possibly additional collateral damage. Predictive Maintenance starts here and tries to predict a possible failure and its cause so early that its prevention can be prepared and carried out in time. In order to be able to predict malfunctions and failures, the industrial plant with its characteristics, as well as wear and ageing processes, must be modelled. Such modelling can be done by replicating its physical properties. However, this is very complex and requires enormous expert knowledge about the plant and about wear and ageing processes of each individual component. Neural networks and machine learning make it possible to train such models using data and offer an alternative, especially when very complex and non-linear behaviour is evident. In order for models to make predictions, as much data as possible about the condition of a plant and its environment and production planning data is needed. In Industrial Internet of Things (IIoT) environments, the amount of available data is constantly increasing. Intelligent sensors and highly interconnected production facilities produce a steady stream of data. The sheer volume of data, but also the steady stream in which data is transmitted, place high demands on the data processing systems. If a participating system wants to perform live analyses on the incoming data streams, it must be able to process the incoming data at least as fast as the continuous data stream delivers it. If this is not the case, the system falls further and further behind in processing and thus in its analyses. This also applies to Predictive Maintenance systems, especially if they use complex and computationally intensive machine learning models. If sufficiently scalable hardware resources are available, this may not be a problem at first. However, if this is not the case or if the processing takes place on decentralised units with limited hardware resources (e.g. edge devices), the runtime behaviour and resource requirements of the type of neural network used can become an important criterion. This thesis addresses Predictive Maintenance systems in IIoT environments using neural networks and Deep Learning, where the runtime behaviour and the resource requirements are relevant. The question is whether it is possible to achieve better runtimes with similarly result quality using a new type of neural network. The focus is on reducing the complexity of the network and improving its parallelisability. Inspired by projects in which complexity was distributed to less complex neural subnetworks by upstream measures, two hypotheses presented in this thesis emerged: a) the distribution of complexity into simpler subnetworks leads to faster processing overall, despite the overhead this creates, and b) if a neural cell has a deeper internal structure, this leads to a less complex network. Within the framework of a qualitative study, an overall impression of Predictive Maintenance applications in IIoT environments using neural networks was developed. Based on the findings, a novel model layout was developed named Sliced Long Short-Term Memory Neural Network (SlicedLSTM). The SlicedLSTM implements the assumptions made in the aforementioned hypotheses in its inner model architecture. Within the framework of a quantitative study, the runtime behaviour of the SlicedLSTM was compared with that of a reference model in the form of laboratory tests. The study uses synthetically generated data from a NASA project to predict failures of modules of aircraft gas turbines. The dataset contains 1,414 multivariate time series with 104,897 samples of test data and 160,360 samples of training data. As a result, it could be proven for the specific application and the data used that the SlicedLSTM delivers faster processing times with similar result accuracy and thus clearly outperforms the reference model in this respect. The hypotheses about the influence of complexity in the internal structure of the neuronal cells were confirmed by the study carried out in the context of this thesis

    AI: Limits and Prospects of Artificial Intelligence

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    The emergence of artificial intelligence has triggered enthusiasm and promise of boundless opportunities as much as uncertainty about its limits. The contributions to this volume explore the limits of AI, describe the necessary conditions for its functionality, reveal its attendant technical and social problems, and present some existing and potential solutions. At the same time, the contributors highlight the societal and attending economic hopes and fears, utopias and dystopias that are associated with the current and future development of artificial intelligence

    Undergraduate Catalog of Studies, 2022-2023

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    Lost Revenue Recognition in E-commerce: Identifying Causes and Implications

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    openIn order for e-commerce companies to remain financially healthy, revenue recognition is essential. The sector encounters various problems, including slow-loading pages, problematic web resources, and errors, which can result in revenue losses. This research aims to investigate the causes of lost revenue in e-commerce and propose algorithmic solutions to address these challenges. This study examines the impact of slow pages, problematic web resources, and errors on revenue recognition in the e-commerce industry. In this study, real-world data is analyzed and used to identify how these factors negatively impact e-commerce companies' revenue. Additionally, the study proposes a methodology for calculating the potential revenue that could have been recognized in the absence of the identified factors contributing to lost revenue recognition. This methodology incorporates machine learning techniques, and data visualization tools to estimate the extent of revenue loss. The resulting insights provide decision-makers in e-commerce companies with valuable information for optimizing revenue recognition strategies and maximizing financial performance. This research aims to identify the causes of revenue loss in e-commerce. In order to improve revenue recognition accuracy and maximize business performance in the digital marketplace, e-commerce companies will need to develop algorithmic solutions and implement revenue calculation methodologies to address these issues

    Deteção de intrusões de rede baseada em anomalias

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    Dissertação de mestrado integrado em Eletrónica Industrial e ComputadoresAo longo dos últimos anos, a segurança de hardware e software tornou-se uma grande preocupação. À medida que a complexidade dos sistemas aumenta, as suas vulnerabilidades a sofisticadas técnicas de ataque têm proporcionalmente escalado. Frequentemente o problema reside na heterogenidade de dispositivos conectados ao veículo, tornando difícil a convergência da monitorização de todos os protocolos num único produto de segurança. Por esse motivo, o mercado requer ferramentas mais avançadas para a monitorizar ambientes críticos à vida humana, tais como os nossos automóveis. Considerando que existem várias formas de interagir com os sistemas de entretenimento do automóvel como o Bluetooth, o Wi-fi ou CDs multimédia, a necessidade de auditar as suas interfaces tornou-se uma prioridade, uma vez que elas representam um sério meio de aceeso à rede interna do carro. Atualmente, os mecanismos de segurança de um carro focam-se na monitotização da rede CAN, deixando para trás as tecnologias referidas e não contemplando os sistemas não críticos. Como exemplo disso, o Bluetooth traz desafios diferentes da rede CAN, uma vez que interage diretamente com o utilizador e está exposto a ataques externos. Uma abordagem alternativa para tornar o automóvel num sistema mais robusto é manter sob supervisão as comunicações que com este são estabelecidas. Ao implementar uma detecção de intrusão baseada em anomalias, esta dissertação visa analisar o protocolo Bluetooth no sentido de identificar interações anormais que possam alertar para uma situação fora dos padrões de utilização. Em última análise, este produto de software embebido incorpora uma grande margem de auto-aprendizagem, que é vital para enfrentar quaisquer ameaças desconhecidas e aumentar os níveis de segurança globais. Ao longo deste documento, apresentamos o estudo do problema seguido de uma metodologia alternativa que implementa um algoritmo baseado numa LSTM para prever a sequência de comandos HCI correspondentes a tráfego Bluetooth normal. Os resultados mostram a forma como esta abordagem pode impactar a deteção de intrusões nestes ambientes ao demonstrar uma grande capacidade para identificar padrões anómalos no conjunto de dados considerado.In the last few years, hardware and software security have become a major concern. As the systems’ complexity increases, its vulnerabilities to several sophisticated attack techniques have escalated likewise. Quite often, the problem lies in the heterogeneity of the devices connected to the vehicle, making it difficult to converge the monitoring systems of all existing protocols into one security product. Thereby, the market requires more refined tools to monitor life-risky environments such as personal vehicles. Considering that there are several ways to interact with the car’s infotainment system, such as Wi-fi, Bluetooth, or CD player, the need to audit these interfaces has become a priority as they represent a serious channel to reach the internal car network. Nowadays, security in car networks focuses on CAN bus monitoring, leaving behind the aforementioned technologies and not contemplating other non-critical systems. As an example of these concerns, Bluetooth brings different challenges compared to CAN as it interacts directly with the user, being exposed to external attacks. An alternative approach to converting modern vehicles and their set of computers into more robust systems is to keep track of established communications with them. By enforcing anomaly-based intrusion detection this dissertation aims to analyze the Bluetooth protocol to identify abnormal user interactions that may alert for a non conforming pattern. Ultimately, such embedded software product incorporates a self-learning edge, which is vital to face newly developed threats and increasing global security levels. Throughout this document, we present the study case followed by an alternative methodology that implements an LSTM based algorithm to predict a sequence of HCI commands corresponding to normal Bluetooth traffic. The results show how this approach can impact intrusion detection in such environments by expressing a high capability of identifying abnormal patterns in the considered data

    An empirical investigation of the relationship between integration, dynamic capabilities and performance in supply chains

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    This research aimed to develop an empirical understanding of the relationships between integration, dynamic capabilities and performance in the supply chain domain, based on which, two conceptual frameworks were constructed to advance the field. The core motivation for the research was that, at the stage of writing the thesis, the combined relationship between the three concepts had not yet been examined, although their interrelationships have been studied individually. To achieve this aim, deductive and inductive reasoning logics were utilised to guide the qualitative study, which was undertaken via multiple case studies to investigate lines of enquiry that would address the research questions formulated. This is consistent with the author’s philosophical adoption of the ontology of relativism and the epistemology of constructionism, which was considered appropriate to address the research questions. Empirical data and evidence were collected, and various triangulation techniques were employed to ensure their credibility. Some key features of grounded theory coding techniques were drawn upon for data coding and analysis, generating two levels of findings. These revealed that whilst integration and dynamic capabilities were crucial in improving performance, the performance also informed the former. This reflects a cyclical and iterative approach rather than one purely based on linearity. Adopting a holistic approach towards the relationship was key in producing complementary strategies that can deliver sustainable supply chain performance. The research makes theoretical, methodological and practical contributions to the field of supply chain management. The theoretical contribution includes the development of two emerging conceptual frameworks at the micro and macro levels. The former provides greater specificity, as it allows meta-analytic evaluation of the three concepts and their dimensions, providing a detailed insight into their correlations. The latter gives a holistic view of their relationships and how they are connected, reflecting a middle-range theory that bridges theory and practice. The methodological contribution lies in presenting models that address gaps associated with the inconsistent use of terminologies in philosophical assumptions, and lack of rigor in deploying case study research methods. In terms of its practical contribution, this research offers insights that practitioners could adopt to enhance their performance. They can do so without necessarily having to forgo certain desired outcomes using targeted integrative strategies and drawing on their dynamic capabilities

    The Witcraft of Seeing Things Differently : Hyperdetermined Humor, Unusual Viewpoints, and Narrative Rhetoric in Terry Pratchett's Discworld Novels

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    Sir Terry Pratchettin maineikasta ja menestynyttä Discworld-romaanisarjaa luonnehditaan yleensä koomiseksi fantasiaksi, ja vaikka sitä on aiemmin tutkittu etupäässä fantasiakirjallisuutena, niin fantasiamiljöön lisäksi toinen näiden kirjojen silmiinpistävä piirre on huumorin ylenpalttinen runsaus. Tässä väitöskirjassa olen valinnut harvinaisemman lähestymistavan tutkiessani Discworld-romaaneja ensisijaisesti humoristisena kirjallisuutena, ja sen mukaisesti väitöskirjani keskeisimpänä tavoitteena on tutkia Terry Pratchettin huumorin poetiikkaa. Tarkemmin sanottuna olen asettanut tässä väitöskirjassa tehtäväkseni kartoittaa Terry Pratchettin huumorille ominaisimmat komiikan keinot ja tutkia, mikä tekee Discworld-romaaneista hauskoja. Discworld-romaaneille ominainen huumorin runsaus koostuu humorististen kuvausten ja koomisten kohtausten tiheän esiintymisen lisäksi komiikan keinojen laajasta valikoimasta. Tässä väitöskirjassa väitän, että Terry Pratchettin huumori on hyperdeterminoitua, mikä tarkoittaa, että hän yhdistelee erilaisia komiikan keinoja samassa kuvauksessa tai kohtauksessa. Siksi Pratchettin huumorin poetiikkaa käsittelevä väitöskirjani on samalla myös tutkimus hyperdeterminoidun huumorin rakentumisesta. Selkeyttääkseni huumorin hyperdeterminaation rakentumista jaottelen komiikan keinot neljään kategoriaan: tilanteellisiin, kontekstuaalisiin, rakenteellisiin ja tyylillisiin. Sovellan tätä jaottelua väittämällä, että humoristista kuvausta tai koomista kohtausta voidaan perustellusti sanoa hyperdeterminoiduksi silloin, kun siinä yhdistellään komiikan keinoja useammasta kuin yhdestä kategoriasta. Pidän Pratchettin huumorille ominaisten komiikan keinojen kartoittamista yhtenä tämän väitöskirjan keskeisimmistä kontribuutioista kirjallisen huumorin tutkimukselle. Tilanteellisista komiikan keinoista tarkastelen Discworld-romaaneista löytämiäni esimerkkejä draamallisesta ironiasta ja absurdista logiikasta. Kontekstuaalisista komiikan keinoista käsittelen Pratchettin parodiaa ja satiiria, kun taas rakenteellisista komiikan keinoista tutkin, kuinka Pratchett käyttää paraprosdokiania, bathosta, toistuvia piloja (”figgin”) ja koomisia alaviitteitä. Tyylillisistä komiikan keinoista tutkailen Pratchettin koomisia kielikuvia (hyperbolia, metaforia, vertauksia ja personifikaatioita), hänen sanaleikkejään (paronomasia, antanaklasis, sanataskut ja kaksikieliset sanaleikit) sekä Pratchettin koomisia eufemismeja. Lisäksi osoitan väitöskirjassani, että Terry Pratchettin huumorille on ominaista kulttuuristen kliseiden (eli tuttujen kulttuuri-ilmiöiden, totunnaisten ajattelutapojen ja vakiintuneiden esittämisen konventioiden) esittäminen humoristisen epätavallisista näkökulmista käsin. Discworld-romaaneissa Pratchett siirtää erilaisia oman maailmamme kulttuuri-ilmiöitä Discworld-nimiseen (suom. Kiekkomaailma) fantasiamaailmaansa, ja tämän maailmojen törmäyttämisen seurauksena kulttuuriset kliseet näyttäytyvät lukijalle samanaikaisesti tuttuina ja koomisen outoina. Tällaiset humoristiset näkökulmat vahvistavat osaltaan huumorin hyperdeterminaatiota. Samalla kun fantasiamiljöö mahdollistaa kahden maailman koomisen törmäyttämisen ja oman maailmamme kulttuuristen kliseiden peilaamisen toisen maailman avulla, huumori toisaalta mahdollistaa Kiekkomaailmassa normaalia fantasiaa vapaamman mielikuvituksen lennon, eikä monia Discworld-romaaneissa kuvattuja asioita, tapahtumia ja ilmiöitä voisi esiintyä maailmoissa, jotka eivät rakennu absurdin logiikan, kulttuurisilla kliseillä leikittelyn ja koomisen liioittelun kaltaisten todellisuuta vääristävien periaatteiden luoman ”taikuuden” varaan. Komiikan keinojen moninaisuuden, hyperdeterminoidun huumorin ja epätavallisten näkökulmien lisäksi tutkin väitöskirjassani sitä, millaisia arvottavia asenteita kertojan humoristiset näkökulmat ja humoristisiin kuvauksiin sisältyvät henkilöhahmojen tunnereaktiot paljastavat. Tulkitsen tällaisen arvottavan huumorin kirjalliseksi retorisen vaikuttamisen keinoksi, jonka avulla kirjailija pyrkii ohjailemaan lukijansa hyväksyviä ja paheksuvia asenteita. Useimmiten Pratchettin huumori on kulttuurikriittistä, eli parodista ja satiirista, mutta toisinaan humoristiset näkökulmat esittävät todellisen maailman kulttuuri-ilmiöitä myönteisinä ja ihailtavina. Väitän tutkimuksessani, että kirjallisuuden retoriikka perustuu tällaisten kielteisten ja myönteisten asenteiden esittämiselle ja että huumori on yksi kertomuksen retoriikan vaikutuskeinoista.Sir Terry Pratchett’s bestselling Discworld series of novels has been commonly described as comic fantasy, and although it has been previously studied mainly as fantasy literature, another conspicuous feature in these novels, in addition to the fantasy milieu, is their rich and abundant humor. In this study, I have chosen the road less travelled by approaching the Discworld novels as humorous literature, and, consequently, my main goal here is to study the poetics of Terry Pratchett’s humor— his “witcraft”. To be more precise, in this dissertation I have set myself the task of mapping out the comic devices that are most characteristic for Terry Pratchett’s witcraft and investigating what makes the Discworld novels funny. The richness of humor that is characteristic for the Discworld novels consists partly of the frequent occurrences of humorous descriptions and comic scenes, but also of the numerous comic devices that Pratchett deploys. In this dissertation, I argue that Terry Pratchett’s humor is hyperdetermined, which means that he tends to combine numerous comic devices in the same description or scene. Consequently, this study on the poetics of Terry Pratchett’s humor is at the same time a study on the construction of hyperdetermined humor. To better understand how hyperdetermined humor is constructed, I have devised a taxonomy that divides comic devices into four categories: situational, contextual, structural, and stylistic. Based on this taxonomy, I argue that the humor of a humorous description or a comic scene can be said to be truly hyperdetermined whenever it combines comic devices from more than one of these categories. I consider mapping out the comic devices that are most characteristic for Terry Pratchett’s witcraft to be one of the major contributions of this dissertation to the academic study of humor in literature. Of situational comic devices, I discuss and analyze examples of dramatic irony and absurd logic that I have detected in the Discworld novels. Of contextual comic devices, I discuss Pratchett’s parody and satire; of structural comic devices, I study Pratchett’s use of paraprosdokian, bathos, figgins (or running gags), and comic footnotes. Of stylistic comic devices, I investigate Pratchett’s comic imagery (hyperboles, metaphors, similes, and personifications), his puns (paronomasia, antanaclasis, portmanteaux, and bilingual puns), as well as Pratchett’s comic euphemisms. In this dissertation, I also demonstrate that representing cultural clichés (i.e., familiar cultural phenomena, customary ways of thinking, and conventional ways of representing) from humorously unusual viewpoints is characteristic for Terry Pratchett’s witcraft. In the Discworld novels, Pratchett transfers various cultural phenomena from the real world, our “Roundworld”, to a fantasy world called the Discworld, and as a result of this interworldly resonance, the cultural clichés of our Roundworld appear to the reader simultaneously as familiar and comically strange. These humorous viewpoints can be viewed as an additional constituent of hyperdetermined humor. While the fantasy setting of the Discworld novels allows Pratchett to set up comic resonance between the worlds, Pratchett’s humor also makes the Discworld a more imaginative and fantastic place than typical fantasy worlds. Many events and phenomena that are represented in the Discworld novels can only exist in a world where reality is distorted and enhanced by the special “magic” of comically absurd logic, playing with cultural clichés, and humorous exaggerations. In addition to the abundance of comic devices, hyperdetermined humor, and humorously unusual viewpoints, I also study in this dissertation what kinds of evaluative attitudes the narrator’s humorous viewpoints and the characters’ emotional reactions reveal. According to my interpretation, such evaluative attitudes are means of narrative rhetoric, where the author attempts to guide the reader’s attitudes of approval or disapproval. Pratchett’s humor is often critical—parodical or satirical—although occasionally the narrator’s humorous viewpoints represent the cultural phenomena of our Roundworld in a positive light, as something admirable. In this dissertation, I argue that narrative rhetoric is based on representing negative and positive attitudes, and that humor is one possible means of narrative rhetoric
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