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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Agent Contribution in Multi-Agent Reinforcement Learning : A Case Study in Remote Electrical Tilt

Emanuelsson, William January 2024 (has links)
As multi-agent reinforcement learning (MARL) continues to evolve and find applications in complex real-world systems, the imperative for explainability in these systems becomes increasingly critical. Central to enhancing this explainability is tackling the credit assignment problem, a key challenge in MARL that involves quantifying the individual contributions of agents toward a common goal. In addressing this challenge, this thesis introduces and explores the application of Local and Global Shapley Values (LSV and GSV) within MARL contexts. These novel adaptations of the traditional Shapley value from cooperative game theory are investigated particularly in the context of optimizing remote electrical tilt in telecommunications antennas. Using both predator-prey and remote electrical tilt environments, the study delves into local and global explanations, examining how the Shapley value can illuminate changes in agent contributions over time and across different states, as well as aggregate these insights over multiple episodes. The research findings demonstrate that the use of Shapley values enhances the understanding of individual agent behaviors, offers insights into policy suboptimalities and environmental nuances, and aids in identifying agent redundancies—a feature with potential applications in energy savings in real-world systems. Altogether, this thesis highlights the considerable potential of employing the Shapley value as a tool in explainable MARL. / I takt med utvecklingen och tillämpningen av multi-agent förstärkningsinlärning (MARL) i komplexa verkliga system, blir behovet av förklarbarhet i dessa system allt mer väsentligt. För att förbättra denna förklarbarhet är det viktigt att lösa problemet med belöningstilldelning, en nyckelutmaning i MARL som innefattar att kvantifiera de enskilda bidragen från agenter mot ett gemensamt mål. I denna uppsats introduceras och utforskas tillämpningen av lokala och globala Shapley-värden (LSV och GSV) inom MARL-sammanhang. Dessa nya anpassningar av det traditionella Shapley-värdet från samarbetsbaserad spelteori undersöks särskilt i sammanhanget av att optimera fjärrstyrda elektriska lutningar i telekommunikationsantenner. Genom att använda både rovdjur-byte och fjärrstyrda elektriska lutningsmiljöer fördjupar studien sig i lokala och globala förklaringar, och undersöker hur Shapley-värdet kan belysa förändringar i agenters bidrag över tid och över olika tillstånd, samt sammanfatta dessa insikter över flera episoder. Resultaten visar att användningen av Shapley-värden förbättrar förståelsen för individuella agentbeteenden, erbjuder insikter i policybrister och miljönyanser, och hjälper till att identifiera agentredundanser – en egenskap med potentiella tillämpningar för energibesparingar i verkliga system. Sammanfattningsvis belyser denna uppsats den betydande potentialen av att använda Shapley-värdet som ett verktyg i förklaringsbar MARL.
62

Enhancing Robustness and Explainability in Language Models : A Case Study on T0 / Förbättra robusthet och förklaring i språkmodeller : En fallstudie på T0

Yutong, Jiang January 2024 (has links)
The rapid advancement of cutting-edge techniques has propelled state-of-the-art (SOTA) language models to new heights. Despite their impressive capabilities across a variety of downstream tasks, large language models still face many challenges such as hallucination and bias. The thesis focuses on two key objectives: first, it measures the robustness of T0_3B and investigates feasible methodologies to enhance the model’s robustness. Second, it targets on the explainability of large language models, aiming to make the intrinsic working mechanism more transparent and, consequently enhance model’s steerability. Motivated by the importance of mitigating non-robust behavior in language models, the thesis initially measures model’s robustness on handling minor perturbation. After that, I proposed and verified an approach to enhance robustness by making input more contextualized, a method that does not require the step of fine-tuning. Moreover, to understand the complex working mechanism of large language models, I designed and introduced two novel visualization tools: ’Logit Lens’ and ’Hidden States Plot in Spherical Coordinate System’. These tools, combined with additional experimental analysis, revealed a noticeable differentiation of the predicted processes between the first predicted token and subsequent tokens. The contributions of the thesis are mainly in the two following aspects: it provides feasible methodologies to enhance the robustness of language models without the need of fine-tuning, and it contributes to the field of explainable AI through the development of two visualization tools that shed light on the understanding of the working mechanism. / Den snabba utvecklingen av banbrytande tekniker har drivit språkmodeller till nya höjder. Trots deras imponerande prestanda över diverse språkrelaterade uppgifter, trots detta har dessa modeller fortfarande problem som hallucinationer och bias. Avhandlingen är centrerad kring två huvudmål: för det första undersöker den robustheten hos T0_3B och undersöker framtida strategier för att förbättra dess robusthet. För det andra utforskar den språkmodellernas ”förklaringsbarhet” (dvs hur väl vi förstår deras beteende), i syfte att göra dem mer transparenta och följaktligen förbättra modellens styrbarhet. Det första vi gör är att visa experiment som vi har satt upp för att mäta modellens robusthet mot mindre störningar. Som svar föreslår och underbygger vi ett tillvägagångssätt för att öka robustheten genom att ge modellen mer kontext när en fråga ställs, en metod som inte kräver vidare träning av modellen. Dessutom, för att förstå den komplexiteten hos språkmodeller, introducerar jag två nya visualiseringsverktyg: Logit Lens och Hidden States Plot i sfäriskt koordinatsystem. Dessa verktyg, i kombination med ytterligare experimentell analys, avslöjar ett diskting mönstr för den första förutspådda ordet jämfört med efterföljande ord. Bidragen från avhandlingen är huvudsakligen i de två följande aspekterna: den ger praktiska åtgärder för att förbättra robustheten hos språkmodeller utan behov av vidare träning, och den bidrar till området för förklarabar AI genom utvecklingen av två visualiseringsverktyg som ökar våran förståelse för hur dessa modeller fungerar.
63

Explainable ML for drug prediction

Diaz-Roncero Gonzalez, Daniel January 2024 (has links)
Cancer may be treated with personalized medicine, meaning that specific patientsmight respond better to specific treatments instead of having a common treatment. TheReference Drug-based Neural Network (RefDNN) predicts whether a particular cancer cellline will resist a determined drug, but it fails to provide an explanations for this prediction.The thesis objective is to research on explainable machine learning methods to extractrule-based explanations from the RefDNN predictions and conclude on how confident wecan be about these explanations and whether they make sense from a biological point ofview. One of such explainable machine learning methods is Local Rule-based Explanation(LORE), which extracts rule-based explanations from any black box model using localdecision trees. In this thesis LORE is applied to explain the predictions of the RefDNNon a drug sensitivity dataset and three experiments are set up. First experiment tests theaccuracy and general performance of the extracted rule-based explanations. Second experimentstests the robustness of the rule-based explanations. Third experiments checks theglobal fidelity of the local decision trees used by LORE to mimic the RefDNN behaviour.Finally, one rule-based decision is explained from a biological point of view and conclusionsare made on the obtained results.
64

Lithium-Ion Battery SOH Forecasting With Deep Learning Augmented By Explainable Machine Learning

Sheikhani, Arman, Agic, Ervin January 2024 (has links)
As Lithium-ion batteries (LiBs) emerge as pivotal energy storage solutions for automotive applications, maintaining their performance and longevity presents challenges due to power and capacity fade influenced by environmental and usage conditions. Thus, to estimate battery degradation, estimating the state of health (SOH) or predicting remaining useful life (RUL) without considering future operational loads, can limit accurate SOH forecasting. Meanwhile, machine learning (ML) models including deep neural networks (DNNs), have become effective techniques for SOH forecasting of LiBs due to their capability to handle various regression problems without relying on physics-based models. The methodology used in this study, helps battery developers link different operational strategies to battery aging. We use inputs such as temperature (T), current (I), and state of charge (SOC) and utilize a feature transformation technique which generates histogram-based stressor features representing the time that the battery cells spend under operational conditions, then investigate the performance of DNN models along with explainable machine learning (XML) techniques (e.g., SHapley Additive exPlanations) in predicting LiB SOH. The comparative analysis leverages an extensive open-source dataset to evaluate the performance of deep learning models such as LSTM, GRU, and FNN. The forecasting is executed in two distinct modes: one capping the forecasted cycles at 520, and another extending the predictions to the end of the battery’s first life (SOH=80%).Furthermore, this study explores the practicality of a lightweight model, e.g., support vector regression (SVR) model, to compare against DNN models for scenarios with constrained computational and memory resources. The results show that utilizing a feature refinement to ensure the coverage of critical features can lead to performance comparable with the DNN (e.g., LSTM) for the SVR model.
65

Information extraction and mapping for KG construction with learned concepts from scientic documents : Experimentation with relations data for development of concept learner

Malik, Muhammad Hamza January 2020 (has links)
Systematic review of research manuscripts is a common procedure in which research studies pertaining a particular field or domain are classified and structured in a methodological way. This process involves, between other steps, an extensive review and consolidation of scientific metrics and attributes of the manuscripts, such as citations, type or venue of publication. The extraction and mapping of relevant publication data, evidently, is a very laborious task if performed manually. Automation of such systematic mapping steps intend to reduce the human effort required and therefore can potentially reduce the time required for this process.The objective of this thesis is to automate the data extraction and mapping steps when systematically reviewing studies. The manual process is replaced by novel graph modelling techniques for effective knowledge representation, as well as novel machine learning techniques that aim to learn these representations. This eventually automates this process by characterising the publications on the basis of certain sub-properties and qualities that give the reviewer a quick high-level overview of each research study. The final model is a concept learner that predicts these sub-properties which in addition addresses the inherent concept-drift of novel manuscripts over time. Different models were developed and explored in this research study for the development of concept learner.Results show that: (1) Graph reasoning techniques which leverage the expressive power in modern graph databases are very effective in capturing the extracted knowledge in a so-called knowledge graph, which allows us to form concepts that can be learned using standard machine learning techniques like logistic regression, decision trees and neural networks etc. (2) Neural network models and ensemble models outperformed other standard machine learning techniques like logistic regression and decision trees based on the evaluation metrics. (3) The concept learner is able to detect and avoid concept drift by retraining the model. / Systematisk granskning av forskningsmanuskript är en vanlig procedur där forskningsstudier inom ett visst område klassificeras och struktureras på ett metodologiskt sätt. Denna process innefattar en omfattande granskning och sammanförande av vetenskapliga mätvärden och attribut för manuskriptet, såsom citat, typ av manuskript eller publiceringsplats. Framställning och kartläggning av relevant publikationsdata är uppenbarligen en mycket mödosam uppgift om den utförs manuellt. Avsikten med automatiseringen av processen för denna typ av systematisk kartläggning är att minska den mänskliga ansträngningen, och den tid som krävs kan på så sätt minskas. Syftet med denna avhandling är att automatisera datautvinning och stegen för kartläggning vid systematisk granskning av studier. Den manuella processen ersätts av avancerade grafmodelleringstekniker för effektiv kunskapsrepresentation, liksom avancerade maskininlärningstekniker som syftar till att lära maskinen dessa representationer. Detta automatiserar så småningom denna process genom att karakterisera publikationerna beserat på vissa subjektiva egenskaper och kvaliter som ger granskaren en snabb god översikt över varje forskningsstudie. Den slutliga modellen är ett inlärningskoncept som förutsäger dessa subjektiva egenskaper och dessutom behandlar den inneboende konceptuella driften i manuskriptet över tiden. Olika modeller utvecklades och undersöktes i denna forskningsstudie för utvecklingen av inlärningskonceptet. Resultaten visar att: (1) Diagrammatiskt resonerande som uttnytjar moderna grafdatabaser är mycket effektiva för att fånga den framställda kunskapen i en så kallad kunskapsgraf, och gör det möjligt att vidareutveckla koncept som kan läras med hjälp av standard tekniker för maskininlärning. (2) Neurala nätverksmodeller och ensemblemodeller överträffade andra standard maskininlärningstekniker baserat på utvärderingsvärdena. (3) Inlärningskonceptet kan detektera och undvika konceptuell drift baserat på F1-poäng och omlärning av algoritmen.
66

Requirements Analysis for AI solutions : a study on how requirements analysis is executed when developing AI solutions

Olsson, Anton, Joelsson, Gustaf January 2019 (has links)
Requirements analysis is an essential part of the System Development Life Cycle (SDLC) in order to achieve success in a software development project. There are several methods, techniques and frameworks used when expressing, prioritizing and managing requirements in IT projects. It is widely established that it is difficult to determine requirements for traditional systems, so a question naturally arises on how the requirements analysis is executed as AI solutions (that even fewer individuals can grasp) are being developed. Little research has been made on how the vital requirements phase is executed during development of AI solutions. This research aims to investigate the requirements analysis phase during the development of AI solutions. To explore this topic, an extensive literature review was made, and in order to collect new information, a number of interviews were performed with five suitable organizations (i.e, organizations that develop AI solutions). The results from the research concludes that the requirements analysis does not differ between development of AI solutions in comparison to development of traditional systems. However, the research showed that there were some deviations that can be deemed to be particularly unique for the development of AI solutions that affects the requirements analysis. These are: (1) the need for an iterative and agile systems development process, with an associated iterative and agile requirements analysis, (2) the importance of having a large set of quality data, (3) the relative deprioritization of user involvement, and (4) the difficulty of establishing timeframe, results/feasibility and the behavior of the AI solution beforehand.
67

Out of sight, out of mind? : Assessing human attribution of object permanence capabilities to self-driving cars

Holmgren, Aksel January 2022 (has links)
Autonomous vehicles are regularly predicted to be on the verge of broad integration into regular traffic. A crucial aspect of successful traffic interactions is one agent’s ability to adequately understand other agents’ capabilities and limitations. Within the current state of the art concerning self-driving cars, there is a discrepancy between what people tend to believe the capabilities of self-driving cars are, and what those capabilities actually are. The aim of this study was to investigate whether people attribute the capacity of object permanence to self-driving cars roughly in the same manner as they would to a human driver. The study was conducted with online participants (N = 105). The results showed that the participants did not attribute object permanence differently between a self-driven car and a human driver. This indicates that people attribute object permanence similarly to self-driving cars as they do toward human drivers. Furthermore, the results indicate no connection between participants’ tendency to anthropomorphize and whether they attributed object permanence or not. The findings provide evidence for the issues connected to the perceptual belief problem in human-robot interaction, where people attribute capabilities to autonomous vehicles that are not there. The results highlight the importance of understanding which mechanisms underlie these attributions as well as when they happen, in order to mitigate unrealistic expectations.
68

Exploring Human-Robot Interaction Through Explainable AI Poetry Generation

Strineholm, Philippe January 2021 (has links)
As the field of Artificial Intelligence continues to evolve into a tool of societal impact, a need of breaking its initial boundaries as a computer science discipline arises to also include different humanistic fields. The work presented in this thesis revolves around the role that explainable artificial intelligence has in human-robot interaction through the study of poetry generators. To better understand the scope of the project, a poetry generators study presents the steps involved in the development process and the evaluation methods. In the algorithmic development of poetry generators, the shift from traditional disciplines to transdisciplinarity is identified. In collaboration with researchers from the Research Institutes of Sweden, state-of-the-art generators are tested to showcase the power of artificially enhanced artifacts. A development plateau is discovered and with the inclusion of Design Thinking methods potential future human-robot interaction development is identified. A physical prototype capable of verbal interaction on top of a poetry generator is created with the new feature of changing the corpora to any given audio input. Lastly, the strengths of transdisciplinarity are connected with the open-sourced community in regards to creativity and self-expression, producing an online tool to address future work improvements and introduce nonexperts to the steps required to self-build an intelligent robotic companion, thus also encouraging public technological literacy. Explainable AI is shown to help with user involvement in the process of creation, alteration and deployment of AI enhanced applications.
69

Interpretation of Dimensionality Reduction with Supervised Proxies of User-defined Labels

Leoni, Cristian January 2021 (has links)
Research on Machine learning (ML) explainability has received a lot of focus in recent times. The interest, however, mostly focused on supervised models, while other ML fields have not had the same level of attention. Despite its usefulness in a variety of different fields, unsupervised learning explainability is still an open issue. In this paper, we present a Visual Analytics framework based on eXplainable AI (XAI) methods to support the interpretation of Dimensionality reduction methods. The framework provides the user with an interactive and iterative process to investigate and explain user-perceived patterns for a variety of DR methods by using XAI methods to explain a supervised method trained on the selected data. To evaluate the effectiveness of the proposed solution, we focus on two main aspects: the quality of the visualization and the quality of the explanation. This challenge is tackled using both quantitative and qualitative methods, and due to the lack of pre-existing test data, a new benchmark has been created. The quality of the visualization is established using a well-known survey-based methodology, while the quality of the explanation is evaluated using both case studies and a controlled experiment, where the generated explanation accuracy is evaluated on the proposed benchmark. The results show a strong capacity of our framework to generate accurate explanations, with an accuracy of 89% over the controlled experiment. The explanation generated for the two case studies yielded very similar results when compared with pre-existing, well-known literature on ground truths. Finally, the user experiment generated high quality overall scores for all assessed aspects of the visualization.
70

Explainable AI techniques for sepsis diagnosis : Evaluating LIME and SHAP through a user study

Norrie, Christian January 2021 (has links)
Articial intelligence has had a large impact on many industries and transformed some domains quite radically. There is tremendous potential in applying AI to the eld of medical diagnostics. A major issue with applying these techniques to some domains is an inability for AI models to provide an explanation or justication for their predictions. This creates a problem wherein a user may not trust an AI prediction, or there are legal requirements for justifying decisions that are not met. This thesis overviews how two explainable AI techniques (Shapley Additive Explanations and Local Interpretable Model-Agnostic Explanations) can establish a degree of trust for the user in the medical diagnostics eld. These techniques are evaluated through a user study. User study results suggest that supplementing classications or predictions with a post-hoc visualization increases interpretability by a small margin. Further investigation and research utilizing a user study surveyor interview is suggested to increase interpretability and explainability of machine learning results.

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