Position: Senior Lecturer and Programme Leader
Location: Room EB.1.104, East Building, Dockland Campus
Telephone: +44 (0) 208 223 2871
Email: s.w.lee@uel.ac.uk
Contact address:
School of Architecture, Computing and Engineering (ACE),
Room EB.1.104,
East Building,
Dockland Campus,
4 - 6 University Way,
London E16 4LZ.
My main area of interest is in the field of Artificial Neural Networks (ANNs) and their applications in pattern recognition, natural langauge processing and intelligence data analysis.
There are many learning methods in the field of Artificial Neural Networks (ANNs). Although the elusive goal of ANNs is to emulate biological, including human learning, depending on the application, one learning rule may be more suitable than another. But the choice is not always clear-cut, despite some fundamental constraints, such as whether the learning is supervised or unsupervised. My research interest centres on addressing the ANN learning styles selection problem by proposing a new adaptive self-optimising reinforcement learning style. In broader sense, my interest lies in the field of artificial neural network (ANN) techniques and applications for pattern recognition and machine learning.
During my PhD, I have developed a new self-optimising reinforcement learning algorithm, known as snap-drift, when incorporated into a modular neural network system, is capable of rapidly adapting to discover provisional solutions that meet criteria imposed by a changing environment. This is analogous to humans optimising selection according to the options available in the surrounding environment.
Keynotes
Book Chapters:
Journal Papers:
Conference Papers:
Collaborations and Fundings:
Applications of Snap-drift Algorithm:
(A) Reinforced Snap-Drift Learning for Proxylet Selection in Active Computer Networks
Sin Wee Lee, Dominic Palmer-Brown and Christopher Roadknight (Collaborative research project with BTexact Research Laboratories)
In this project, a new continuous learning method is applied to the problem of optimizing the selection of services in response to user requests in an active computer network simulation environment. The learning is an enhanced version of the ‘snap-drift’ algorithm, which employs the complementary concepts of fast, minimalist learning (snap) and slower drift (towards the input patterns) learning, in a non-stationary environment where new patterns are continually introduced. Snap is based on Adaptive Resonance Theory (ART), and drift on Learning Vector Quantisation (LVQ). The new algorithm swaps its learning style between the two modes of self-organisation when declining performance levels are received, but maintains the same learning style during episodes of improved performance. Performance updates occur at the end of each epoch. Reinforcement also occurs by maintaining successful adaptations, since learning is enabled with a probability that increases with declining performance. The method is capable of rapidly re-learning and is used in the design of a modular neural network system, Performance-guided Adaptive Resonance Theory (P-ART).
(B) Data Analysis of Network Manager’s Behaviour
Helen Donelan, Colin Pattinson, Dominic Palmer-Brown and Sin Wee Lee (Collaborative research project with Computer Communications Research Group, Leeds Metropolitan University)
The aim of this research is to provide a tool for exposing trainee network managers, through a life like situation, where both normal network operation and fault scenario could be simulated in order to train the network manager. P-ART is adapted and implemented to analyse the interaction data to enable an assessment of the capabilities of the network manager as well as the understanding of how the network management tasks are being approached. The results show that P-ART can be used to uncover hidden patterns in user behaviour and provide novel insights into that behaviour. The output formed by P-ART is used to compare instances of good and bad practice and reveal patterns embedded within the data that are difficult to recognise.
(C) Feature discovery and clustering of speech waveforms from non-stammering and stammering speakers
Sin Wee Lee, Dominic Palmer-Brown, Nicole Whitworth and Monica Bray (Collaborative research project with Phonetics Research Group, Leeds Metropolitan University)
P-ART is proposed to act as a tool for feature discovery and clustering of speech waveforms from non-stammering and stammering speakers. The learning algorithm is an unsupervised version of snap-drift which employs the complementary concepts of fast, minimalist learning (snap) & slow drift (towards the input pattern) learning. The Snap-Drift Neural Network (SDNN) is toggled between snap and drift modes on successive epochs. The speech waveforms are drawn from a phonetically annotated corpus, which facilitates phonetic interpretation of the classes of patterns discovered by the SDNN.
(D) Phrase recognition in a Connectionist Language Parser
Sin Wee Lee and Dominic Palmer-Brown
The application involves phrase recognition using a set of phrases from the Lancaster Parsed Corpus (LPC) (Garside, 1987). The learning algorithm is the classifier version of snap-drift. The twin modes of minimalist learning (snap) and slow drift towards the input pattern are applied alternately. Each neuron of the Snap-Drift Neural Network (SDNN) swaps between snap and drift modes when declining performance is indicated on that particular node, so that each node has its learning mode toggled independently of the other nodes. Learning on each node is also reinforced by enabling learning with a probability that decreases with increasing performance. The simulations demonstrate that learning is stable, and the results have consistently shown similar classification performance and advantages in terms of speed in comparison with a Multilayer Perceptron (MLP) and backpropagation neural networks applied to the same problem.
(E) Cluster Analysis on Iris Data using Snap-drift Algorithm
Sin Wee Lee and Dominic Palmer-Brown
The unsupervised snap-drift algorithm will be used for clustering the iris data make famous by Fisher (1936) that has been widely used in cluster analysis. It consists of three species, namely, Iris Setosa, Iris Virginia and Iris Versicolor. Each species contains fifty data points, and each data point has 4 dimensions, which represents sepal length, sepal width, petal length and petal width. Unsupervised snap-drift, used in the feature discovery of phonetics speech is used to do cluster analysis of these real-value iris data, preliminary results shows that after a small number of epochs, the system gets 98% reliably correct classification, using about 10 output categorie.
(F) Diagnostic Feedback tool for Virtual Learning Environment
Sin Wee Lee, Dominic Palmer-Brown, Chrisina Draganova
Snap-drift Neural Networks (SDNNs), which employ the complementary concepts of fast, minimalist (snap) learning and slow (drift towards the input pattern) learning is used for the automatic generation of diagnostic feedback for students in an e-learning environment. By discovering the hidden features in the students' responses, such as those to multiple choice questions, typical error patterns, and by taking into account levels of question difficulty, and linguistic (phrasal and lexical) analysis/recognition in short answers, the SDNN will select the most appropriate feedback mix from a corpus. This system will be tested on 'live' students to facilitate automatic diagnosis of deficits in areas of knowledge and to provide specific guidance.

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