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Dr. GEORGIOS SAMAKOVITIS
University of Greenwich

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0 Banking Technologies
0 Enterprise Architecture
0 Fraud Detection
0 Knowledge Management Systems
0 Money Laundering

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Journal article
Published: 28 December 2020 in Applied Sciences
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This work presents an event-driven Extract, Transform, and Load (ETL) pipeline serverless architecture and provides an evaluation of its performance over a range of dataflow tasks of varying frequency, velocity, and payload size. We design an experiment while using generated tabular data throughout varying data volumes, event frequencies, and processing power in order to measure: (i) the consistency of pipeline executions; (ii) reliability on data delivery; (iii) maximum payload size per pipeline; and, (iv) economic scalability (cost of chargeable tasks). We run 92 parameterised experiments on a simple AWS architecture, thus avoiding any AWS-enhanced platform features, in order to allow for unbiased assessment of our model’s performance. Our results indicate that our reference architecture can achieve time-consistent data processing of event payloads of more than 100 MB, with a throughput of 750 KB/s across four event frequencies. It is also observed that, although the utilisation of an SQS queue for data transfer enables easy concurrency control and data slicing, it becomes a bottleneck on large sized event payloads. Finally, we develop and discuss a candidate pricing model for our reference architecture usage.

ACS Style

Antreas Pogiatzis; Georgios Samakovitis. An Event-Driven Serverless ETL Pipeline on AWS. Applied Sciences 2020, 11, 191 .

AMA Style

Antreas Pogiatzis, Georgios Samakovitis. An Event-Driven Serverless ETL Pipeline on AWS. Applied Sciences. 2020; 11 (1):191.

Chicago/Turabian Style

Antreas Pogiatzis; Georgios Samakovitis. 2020. "An Event-Driven Serverless ETL Pipeline on AWS." Applied Sciences 11, no. 1: 191.

Journal article
Published: 14 December 2020 in Applied Sciences
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Information privacy is a critical design feature for any exchange system, with privacy-preserving applications requiring, most of the time, the identification and labelling of sensitive information. However, privacy and the concept of “sensitive information” are extremely elusive terms, as they are heavily dependent upon the context they are conveyed in. To accommodate such specificity, we first introduce a taxonomy of four context classes to categorise relationships of terms with their textual surroundings by meaning, interaction, precedence, and preference. We then propose a predictive context-aware model based on a Bidirectional Long Short Term Memory network with Conditional Random Fields (BiLSTM+CRF) to identify and label sensitive information in conversational data (multi-class sensitivity labelling). We train our model on a synthetic annotated dataset of real-world conversational data categorised in 13 sensitivity classes that we derive from the P3P standard. We parameterise and run a series of experiments featuring word and character embeddings and introduce a set of auxiliary features to improve model performance. Our results demonstrate that the BiLSTM+CRF model architecture with BERT embeddings and WordShape features is the most effective (F1 score 96.73%). Evaluation of the model is conducted under both temporal and semantic contexts, achieving a 76.33% F1 score on unseen data and outperforms Google’s Data Loss Prevention (DLP) system on sensitivity labelling tasks.

ACS Style

Antreas Pogiatzis; Georgios Samakovitis. Using BiLSTM Networks for Context-Aware Deep Sensitivity Labelling on Conversational Data. Applied Sciences 2020, 10, 8924 .

AMA Style

Antreas Pogiatzis, Georgios Samakovitis. Using BiLSTM Networks for Context-Aware Deep Sensitivity Labelling on Conversational Data. Applied Sciences. 2020; 10 (24):8924.

Chicago/Turabian Style

Antreas Pogiatzis; Georgios Samakovitis. 2020. "Using BiLSTM Networks for Context-Aware Deep Sensitivity Labelling on Conversational Data." Applied Sciences 10, no. 24: 8924.

Journal article
Published: 01 July 2020 in European Journal of Electrical Engineering and Computer Science
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Asset value predictability remains a major research concern in financial market especially when considering the effect of unprecedented market fluctuations on the behaviour of market participants. This paper presents preliminary results toward the building a reliable forward problem on ensemble approach IPCBR model, that leverages the capabilities of Case based Reasoning(CBR) and Inverse Problem Techniques (IPTs) to describe and model abnormal stock market fluctuations (often associated with asset bubbles) using datasets from historical stock market prices. The framework uses a rich set of past observations and geometric pattern description and then applies a CBR to formulate the forward problem, Inverse Problem formulation is then applied to identify a set of parameters that can statistically be associated with the occurrence of the observed patterns. This research work presents a formative strategy aimed to determine the causes of behaviour, rather than predict future time series points which brings a novel perspective to the problem of asset bubbles predictability, and a deviation from the existing research trend. The results depict the stock dynamics and statistical fluctuating evidence associated with the envisaged bubble problem.

ACS Style

Francis Ekpenyong; Georgios Samakovitis; Stelios Kapetanakis; Miltos Petridis. Towards the Ensemble: IPCBR Model in Investigating Financial Bubbles. European Journal of Electrical Engineering and Computer Science 2020, 4, 1 .

AMA Style

Francis Ekpenyong, Georgios Samakovitis, Stelios Kapetanakis, Miltos Petridis. Towards the Ensemble: IPCBR Model in Investigating Financial Bubbles. European Journal of Electrical Engineering and Computer Science. 2020; 4 (4):1.

Chicago/Turabian Style

Francis Ekpenyong; Georgios Samakovitis; Stelios Kapetanakis; Miltos Petridis. 2020. "Towards the Ensemble: IPCBR Model in Investigating Financial Bubbles." European Journal of Electrical Engineering and Computer Science 4, no. 4: 1.

Conference paper
Published: 01 December 2015 in 2015 18th International Conference on Computer and Information Technology (ICCIT)
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Mobile governance (m-governance), which is considered as an extension of electronic governance (e-governance), has enormous opportunity to flourish in the developing countries due to the rapid increase of mobile phone subscribers. There are also a number of challenges accompanying the opportunities for design and implementation of mobile governance in developing countries. In this paper a conceptual framework is proposed based on secondary research to justify the current mobile governance situation of developing countries, with Bangladesh being selected as the case study, by explaining the essential components of a mobile governance system and the surrounding environmental factors that have influence upon it.

ACS Style

Shahid Hossain; Georgios Samakovitis; Liz Bacon; Lachlan MacKinnon. A conceptual framework for design of mobile governance in developing countries: The case of Bangladesh. 2015 18th International Conference on Computer and Information Technology (ICCIT) 2015, 161 -166.

AMA Style

Shahid Hossain, Georgios Samakovitis, Liz Bacon, Lachlan MacKinnon. A conceptual framework for design of mobile governance in developing countries: The case of Bangladesh. 2015 18th International Conference on Computer and Information Technology (ICCIT). 2015; ():161-166.

Chicago/Turabian Style

Shahid Hossain; Georgios Samakovitis; Liz Bacon; Lachlan MacKinnon. 2015. "A conceptual framework for design of mobile governance in developing countries: The case of Bangladesh." 2015 18th International Conference on Computer and Information Technology (ICCIT) , no. : 161-166.

Proceedings article
Published: 01 January 2009 in 2009 WRI World Congress on Computer Science and Information Engineering
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Protocols in ad hoc networks are not designed with mobility in mind. Recent research reveals that mobility impacts all the layers of the protocol stack. Specifically, more realistic mobility models that are extracted from real user traces for the vehicular and pedestrian scenarios show that wireless nodes tend to cluster around popular locations. The contributions of this paper are two-fold. First, it suggests cross layer design, as a promising approach, in designing ad hoc protocols with mobility in mind. Therefore, it provides a survey of the methodologies used in wireless cross layer studies. Second, it presents a framework for cross layer and flexible ad hoc protocol design, which integrates mobility into protocol design.

ACS Style

Arta Doci; Georgios Samakovitis; Vijaya Raju. Impact of Mobility in Ad Hoc Protocol Design. 2009 WRI World Congress on Computer Science and Information Engineering 2009, 1, 38 -43.

AMA Style

Arta Doci, Georgios Samakovitis, Vijaya Raju. Impact of Mobility in Ad Hoc Protocol Design. 2009 WRI World Congress on Computer Science and Information Engineering. 2009; 1 ():38-43.

Chicago/Turabian Style

Arta Doci; Georgios Samakovitis; Vijaya Raju. 2009. "Impact of Mobility in Ad Hoc Protocol Design." 2009 WRI World Congress on Computer Science and Information Engineering 1, no. : 38-43.

Journal article
Published: 01 October 1997 in Dental Traumatology
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“Double teeth” is a root malformation in the dentition and the purpose of this study was to reconstruct three‐dimensionally the external and internal morphology of two “double teeth”. The first set of “double teeth” was formed by the conjunction of a mandibular molar and a premolar, and the second by a conjunction of a maxillary molar and a supernumerary tooth. The process of 3‐D reconstruction included serial cross‐sectioning, photographs of the sections, digitization of the photographs, extraction of the boundaries of interest for each section, surface representation using triangulation and, finally, surface rendering using photorealistic effects. The resulting three‐dimensional representations of the two teeth helped us visualize their external and internal anatomy. The results showed: a) in the first case, fusion of the radical and coronal dentin, as well as fusion of the pulp chambers; and b) in the second case, fusion only of the radical dentin and the pulp chambers.

ACS Style

K. Lyroudia; Georgios Mikrogeorgis; N. Nikopoulos; Georgios Samakovitis; I. Molyvdas; I. Pitas. Computerized 3-D reconstruction of two "double teeth". Dental Traumatology 1997, 13, 218 -222.

AMA Style

K. Lyroudia, Georgios Mikrogeorgis, N. Nikopoulos, Georgios Samakovitis, I. Molyvdas, I. Pitas. Computerized 3-D reconstruction of two "double teeth". Dental Traumatology. 1997; 13 (5):218-222.

Chicago/Turabian Style

K. Lyroudia; Georgios Mikrogeorgis; N. Nikopoulos; Georgios Samakovitis; I. Molyvdas; I. Pitas. 1997. "Computerized 3-D reconstruction of two "double teeth"." Dental Traumatology 13, no. 5: 218-222.

Journal article
Published: 01 February 1997 in Journal of Endodontics
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Two mandibular second molars, with an indication of C-shape morphology were processed for 3-D reconstruction. After serial cross sectioning, photographs of the sections were digitized and by using surface representation, 3D reconstruction was achieved. The first molar as the 3D reconstruction showed was single rooted with one C-shaped root canal with two foramens, while the second one was double rooted with two root canals, one C-shaped and one thin, having a common foramen.

ACS Style

Kleoniki Lyroudia; Georgios Samakovitis; Ioannis Pitas; Theodoros Lambrianidis; Ioannis Molyvdas; Georgios Mikrogeorgis. 3D reconstruction of two C-shape mandibular molars. Journal of Endodontics 1997, 23, 101 -104.

AMA Style

Kleoniki Lyroudia, Georgios Samakovitis, Ioannis Pitas, Theodoros Lambrianidis, Ioannis Molyvdas, Georgios Mikrogeorgis. 3D reconstruction of two C-shape mandibular molars. Journal of Endodontics. 1997; 23 (2):101-104.

Chicago/Turabian Style

Kleoniki Lyroudia; Georgios Samakovitis; Ioannis Pitas; Theodoros Lambrianidis; Ioannis Molyvdas; Georgios Mikrogeorgis. 1997. "3D reconstruction of two C-shape mandibular molars." Journal of Endodontics 23, no. 2: 101-104.