Thimal Kempitiya

Dr. Thimal Kempitiya

orcid

Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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11 July 2019 in IEEE Transactions on Intelligent Transportation Systems
Verified
Journal Article
Open access
DNDinithi Nallaperuma
Dinithi Nallaperuma
Rashmika NawaratneRashmika Nawaratne
Rashmika Nawaratne
TBTharindu Bandaragoda
Tharindu Bandaragoda
AAAchini Adikari
Achini Adikari
SNSu Nguyen
Su Nguyen
DPDakshan Pothuhera
Dakshan Pothuhera
The technological landscape of intelligent transport systems (ITS) has been radically transformed by the emergence of the big data streams generated by the Internet of Things (IoT), smart sensors, surveillance feeds, social media, as well as growing infrastructure needs. It is timely and pertinent that ITS harness the potential of an artificial intelligence (AI) to develop the big data-driven smart traffic management solutions for effective decision-making. The existing AI techniques that function in isolation exhibit clear limitations in developing a comprehensive platform due to the dynamicity of big data streams, high-frequency unlabeled data generation from the heterogeneous data sources, and volatility of traffic conditions. In this paper, we propose an expansive smart traffic management platform (STMP) based on the unsupervised online incremental machine learning, deep learning, and deep reinforcement learning to address these limitations. The STMP integrates the heterogeneous big data streams, such as the IoT, smart sensors, and social media, to detect concept drifts, distinguish between the recurrent and non-recurrent traffic events, and impact propagation, traffic flow forecasting, commuter sentiment analysis, and optimized traffic control decisions. The platform is successfully demonstrated on 190 million records of smart sensor network traffic data generated by 545,851 commuters and corresponding social media data on the arterial road network of Victoria, Australia.

16 November 2022 in IEEE Transactions on Neural Networks and Learning Systems
Verified
Journal Article
Closed access
EOEvgeny Osipov
Evgeny Osipov
SKSachin Kahawala
Sachin Kahawala
DHDilantha Haputhanthri
Dilantha Haputhanthri
TKThimal Kempitiya
Thimal Kempitiya
DSDaswin De Silva
Daswin De Silva
DKDenis Kleyko
Denis Kleyko
Motivated by recent innovations in biologically inspired neuromorphic hardware, this article presents a novel unsupervised machine learning algorithm named Hyperseed that draws on the principles of vector symbolic architectures (VSAs) for fast learning of a topology preserving feature map of unlabeled data. It relies on two major operations of VSA, binding and bundling. The algorithmic part of Hyperseed is expressed within the Fourier holographic reduced representations (FHRR) model, which is specifically suited for implementation on spiking neuromorphic hardware. The two primary contributions of the Hyperseed algorithm are few-shot learning and a learning rule based on single vector operation. These properties are empirically evaluated on synthetic datasets and on illustrative benchmark use cases, IRIS classification, and a language identification task using the $n$ -gram statistics. The results of these experiments confirm the capabilities of Hyperseed and its applications in neuromorphic hardware.

13 March 2024 in Biomimetics
Verified
Journal Article
Open access
PDF file
TKThimal Kempitiya
Thimal Kempitiya
DADamminda Alahakoon
Damminda Alahakoon
EOEvgeny Osipov
Evgeny Osipov
SKSachin Kahawala
Sachin Kahawala
DSDaswin De Silva
Daswin De Silva
We propose a new nature- and neuro-science-inspired algorithm for spatiotemporal learning and prediction based on sequential recall and vector symbolic architecture. A key novelty is the learning of spatial and temporal patterns as decoupled concepts where the temporal pattern sequences are constructed using the learned spatial patterns as an alphabet of elements. The decoupling, motivated by cognitive neuroscience research, provides the flexibility for fast and adaptive learning with dynamic changes to data and concept drift and as such is better suited for real-time learning and prediction. The algorithm further addresses several key computational requirements for predicting the next occurrences based on real-life spatiotemporal data, which have been found to be challenging with current state-of-the-art algorithms. Firstly, spatial and temporal patterns are detected using unsupervised learning from unlabeled data streams in changing environments; secondly, vector symbolic architecture (VSA) is used to manage variable-length sequences; and thirdly, hyper dimensional (HD) computing-based associative memory is used to facilitate the continuous prediction of the next occurrences in sequential patterns. The algorithm has been empirically evaluated using two benchmark and three time-series datasets to demonstrate its advantages compared to the state-of-the-art in spatiotemporal unsupervised sequence learning where the proposed ST-SOM algorithm is able to achieve 45% error reduction compared to HTM algorithm.

17 October 2024 in Technologies
Verified
Journal Article
Open access
PDF file
JWJinrong Wu
Jinrong Wu
Su NguyenSu Nguyen
Su Nguyen
TKThimal Kempitiya
Thimal Kempitiya
DADamminda Alahakoon
Damminda Alahakoon
Machine learning is regarded as an effective approach in network intrusion detection, and has gained significant attention in recent studies. However, few intrusion detection methods have been successfully applied to detect anomalies in large-scale network traffic data, and low explainability of the complex algorithms has caused concerns about fairness and accountability. A further problem is that many intrusion detection systems need to work with distributed data sources in the cloud. In this paper, we propose an intrusion detection method based on distributed computing to learn the latent representations from large-scale network data with lower computation time while improving the intrusion detection accuracy. Our proposed classifier, based on a novel hierarchical algorithm combining adaptability and visualization ability from a self-structured unsupervised learning algorithm and achieving explainability from self-explainable supervised algorithms, is able to enhance the understanding of the model and data. The experimental results show that our proposed method is effective, efficient, and scalable in capturing the network traffic patterns and detecting detailed network intrusion information such as type of attack with high detection performance, and is an ideal method to be applied in cloud-computing environments.

22 November 2015
Verified
Book Chapter
Closed access
PDF file
TRThilina Rathnayake
Thilina Rathnayake
MWMaheshakya Wijewardena
Maheshakya Wijewardena
TKThimal Kempitiya
Thimal Kempitiya
KRKevin Rathnasekara
Kevin Rathnasekara
TGThushan Ganegedara
Thushan Ganegedara
DADamminda Alahakoon
Damminda Alahakoon