[CT4101]: Add Week 1 lecture notes
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\pagenumbering{arabic}
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\section{Introduction}
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\subsection{Lecturer Contact Details}
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\begin{itemize}
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\item Dr. Frank Glavin.
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\item \href{mailto://frank.glavin@universityofgalway.ie}{\texttt{frank.glavin@universityofgalway.ie}}
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\end{itemize}
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\subsection{Grading}
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\begin{itemize}
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\item Continuous Assessment: 30\% (2 assignments, worth 15\% each).
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\item Written Exam: 70\% (Last 2 year's exam papers most relevant).
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\end{itemize}
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\subsection{Module Overview}
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\textbf{Machine Learning (ML)} allows computer programs to improve their performance with experience (i.e., data).
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This module is targeted at learners with no prior ML experience, but with university experience of mathematics \&
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statistics and \textbf{strong} programming skills.
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The focus of this module is on practical applications of commonly used ML algorithms, including deep learning
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applied to computer vision.
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Students will learn to use modern ML frameworks (e.g., scikit-learn, Tensorflow / Keras) to train \& evaluate
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models for common categories of ML task including classification, clustering, \& regression.
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\subsubsection{Learning Objectives}
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On successful completion, a student should be able to:
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\begin{enumerate}
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\item Explain the details of commonly used Machine Learning algorithms.
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\item Apply modern frameworks to develop models for common categories of Machine Learning task, including
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classification, clustering, \& regression.
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\item Understand how Deep Learning can be applied to computer vision tasks.
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\item Pre-process datasets for Machine Learning tasks using techniques such as normalisation \& feature
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selection.
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\item Select appropriate algorithms \& evaluation metrics for a given dataset \& task.
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\item Choose appropriate hyperparameters for a range of Machine Learning algorithms.
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\item Evaluate \& interpret the results produced by Machine Learning models.
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\item Diagnose \& address commonly encountered problems with Machine Learning models.
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\item Discuss ethical issues \& emerging trends in Machine Learning.
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\end{enumerate}
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\section{What is Machine Learning?}
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There are many possible definitions for ``machine learning'':
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\begin{itemize}
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\item Samuel, 1959: ``Field of study that gives computers the ability to learn without being explicitly
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programmed''.
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\item Witten \& Frank, 1999: ``Learning is changing behaviour in a way that makes \textit{performance} better
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in the future''.
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\item Mitchelll, 1997: ``Improvement with experience at some task''.
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A well-defined ML problem will improve over task $T$ with regards to \textbf{performance} measure $P$,
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based on experience $E$.
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\item Artificial Intelligence $\neq$ Machine Learning $\neq$ Deep Learning.
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\item Artificial Intelligence $\not \supseteq$ Machine Learning $\not \supseteq$ Deep Learning.
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\end{itemize}
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Machine Learning techniques include:
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\begin{itemize}
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\item Supervised learning.
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\item Unsupervised learning.
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\item Semi-Supervised learning.
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\item Reinforcement learning.
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\end{itemize}
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Major types of ML task include:
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\begin{enumerate}
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\item Classification.
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\item Regression.
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\item Clustering.
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\item Co-Training.
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\item Relationship discovery.
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\item Reinforcement learning.
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\end{enumerate}
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Techniques for these tasks include:
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\begin{enumerate}
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\item \textbf{Supervised learning:}
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\begin{itemize}
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\item \textbf{Classification:} decision trees, SVMs.
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\item \textbf{Regression:} linear regression, neural nets, $k$-NN (good for classification too).
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\end{itemize}
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\item \textbf{Unsupervised learning:}
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\begin{itemize}
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\item \textbf{Clustering:} $k$-Means, EM-clustering.
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\item \textbf{Relationship discovery:} association rules, bayesian nets.
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\end{itemize}
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\item \textbf{Semi-Supervised learning:}
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\begin{itemize}
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\item \textbf{Learning from part-labelled data:} co-training, transductive learning (combines ideas
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from clustering \& classification).
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\end{itemize}
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\item \textbf{Reward-Based:}
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\begin{itemize}
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\item \textbf{Reinforcement learning:} Q-learning, SARSA.
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\end{itemize}
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\end{enumerate}
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In all cases, the machine searches for a \textbf{hypothesis} that best describes the data presented to it.
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Choices to be made include:
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\begin{itemize}
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\item How is the hypothesis expressed? e.g., mathematical equation, logic rules, diagrammatic form, table,
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parameters of a model (e.g. weights of an ANN), etc.
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\item How is search carried out? e.g., systematic (breadth-first or depth-first) or heuristic (most promising
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first).
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\item How do we measure the quality of a hypothesis?
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\item What is an appropriate format for the data?
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\item How much data is required?
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\end{itemize}
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To apply ML, we need to know:
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\begin{itemize}
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\item How to formulate a problem.
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\item How to prepare the data.
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\item How to select an appropriate algorithm.
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\item How to interpret the results.
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\end{itemize}
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To evaluate results \& compare methods, we need to know:
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\begin{itemize}
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\item The separation between training, testing, \& validation.
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\item Performance measures such as simple metrics, statistical tests, \& graphical methods.
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\item How to improve performance.
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\item Ensemble methods.
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\item Theoretical bounds on performance.
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\end{itemize}
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\subsection{Data Mining}
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\textbf{Data Mining} is the process of extracting interesting knowledge from large, unstructured datasets.
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This knowledge is typically non-obvious, comprehensible, meaningful, \& useful.
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\\\\
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The storage ``law'' states that storage capacity doubles every year, faster than Moore's ``law'', which may results
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in write-only ``data tombs''.
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Therefore, developments in ML may be essential to be able to process \& exploit this lost data.
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\subsection{Big Data}
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\textbf{Big Data} consists of datasets of scale \& complexity such that they can be difficult to process using
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current standard methods.
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The data scale dimensions are affected by one or more of the ``3 Vs'':
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\begin{itemize}
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\item \textbf{Volume:} terabytes \& up.
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\item \textbf{Velocity:} from batch to streaming data.
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\item \textbf{Variety:} numeric, video, sensor, unstructured text, etc.
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\end{itemize}
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It is also fashionable to add more ``Vs'' that are not key:
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\begin{itemize}
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\item \textbf{Veracity:} quality \& uncertainty associated with items.
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\item \textbf{Variability:} change / inconsistency over time.
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\item \textbf{Value:} for the organisation.
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\end{itemize}
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Key techniques for handling big data include: sampling, inductive learning, clustering, associations, \& distributed
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programming methods.
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\end{document}
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