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Stephen P. Ierodiaconou

Software Engineer

I am an enthusiastic and diligent engineer. I love to strive for a balance of engineering quality and speed of delivery and always try to understand a problem's cost vs impact trade off. Currently working for Mangrove Root providing software and technical services. Previously a lead developer at Hassle.com and a team lead and full-stack JavaScript developer at zeebox.

An old personal tech blog is here and my company one is here

Contact me

Skills/TLDR;

JavaScript/TypeScript, node.js, React.js, Ruby, technical team lead, image and video signal processing

Experience

Freelance

Software Developer • 2016+

Software development and technical consulting with Mangrove Root Limited. Primarily node.js and JavaScript/TypeScript. Experience with React.js and Angular.js on front end. Also experience developing universal React applications with next.js. I also provide advice and help to startups, e.g. architecture, product process and hiring (technical screening and interviewing for front/back end JavaScript).

Hassle.com

Lead Developer • 2014 — 2016

Marketplace product connecting customer and domestic cleaners. Early employee until successful acquisition by Helpling GmbH. Worked closely with business stakeholders. Worked as lead developer & made technical/architectural decisions with CTO. Helped with hiring and development of the team of engineers and tried to guide and motivate the team members. Helped shape a culture of delivery and product development ownership. Strove for a lean and iterative product development process while trying to maintain the right engineering quality.

  • Help define & iterate on product development process
  • Technical team leadership and development
  • Ruby on Rails, JavaScript/AngularJS. Mobile app built with Typescript
  • Setup & administration of infrastructure and services

Beamly (formely zeebox), UK

Tech Team Lead • 2013 — 2014, Software engineer • 2011 — 2013

A social network for TV. Early employee, initially as a front end developer and then as a technical team lead. Worked with product owners on feasibility and deliverables. Managed the team backlog, drove planning meetings and retrospectives, ensured transparency & communication of the Sprint goals and managed expectations with product stake holders.

  • node.js JavaScript developer. Helped introduce node.js stack in to zeebox. Developed numerous back ends with node.js, both in a team and individually. Contributed to zeebox common framework. TDD (w. mocha and sinon.js), worked with express.js, lodash, q, request, node-canvas.
  • JavaScript developer on zeebox SPA (Backbone, require.js, jQuery and socket.io)
  • 6 months with Scala, worked on core client facing web services (Akka/Netty)
  • Experience with AWS infrastructure

Freelance

Software Developer • 2010 — 2011

Web application development with JavaScript (Cappuccino) for Architecture 00:/ and teaching tool development in Matlab for the University of Bristol.

Open Source

Projects/contributions

See my GitHub account.

Research & Publications

PhD in Image and Video Processing

Content Based Image Compression Using Texture Analysis and Synthesis

University of Bristol, UK • March 2011
Since demand for image and video content continues to outstrip available bandwidth there is a need for improved image and video compression techniques. However, improvements in traditional approaches are providing diminishing returns and thus new redundancies in visual content must be exploited. In this thesis a new architecture for image compression is proposed in which textures are removed from a source image and replaced using perceptually similar synthesised textures during decoding. Read more... Bibtex

Unsupervised image compression using graphcut texture synthesis

S. Ierodiaconou, J. Byrne, D.R. Bull, D. Redmill & P. Hill • Nov 2009
An unsupervised image compression-by-synthesis system is proposed utilising wavelet based image segmentation and analysis combined with patch based texture synthesis. High perceptual quality is ensured using an artefact detection algorithm in the encoder loop. EBCOT is used to transform code texture samples and residual image data. Resulting bitrate savings of up to approximately 17% over JPEG2000 for little change in perceptual quality have been shown. IET — Bibtex

Unsupervised image compression-by-synthesis within a JPEG framework

J. Byrne, S. Ierodiaconou, D.R. Bull, D. Redmill & P. Hill • Oct 2008
An image compression scheme is proposed, utilising wavelet- based image segmentation and texture analysis, and patch- based texture synthesis. This has been incorporated into a JPEG framework. Homogeneous textured regions are identified and removed prior to transform coding. These regions are then replaced at the decoder by synthesis from marked samples, and colour matched to ensure similarity to the original. Experimental results on natural images show bitrate savings of over 18% compared with JPEG for little change in measured visual quality. IET — Bibtex

Implementation and Optimisation of a Video Object Segmentation Algorithm on an Embedded DSP Platform

S.P. Ierodiaconou, N. Dahnoun and L.Q. Xu • June 2006
An image compression scheme is proposed, utilising wavelet- based image segmentation and texture analysis, and patch- based texture synthesis. This has been incorporated into a JPEG framework. Homogeneous textured regions are identified and removed prior to transform coding. These regions are then replaced at the decoder by synthesis from marked samples, and colour matched to ensure similarity to the original. Experimental results on natural images show bitrate savings of over 18% compared with JPEG for little change in measured visual quality. IET — Bibtex

Education

University of Bristol, UK

MEng Electrical and Electronic Engineering • 2002 — 2006

Modules including: Advanced Computer Architecture, C Programming, Image & Video Coding, Digital Filters & Spectral Analysis, Mathematics, Neural Networks. Final Year Research Project with BT Exact (now BT Innovation): Developing an embedded component to a video surveillance system using a Digital Signal Processor and RTOS (w. C/assembly). Resulting in conference publication and prize.

Recognition

UoB Research Reception • 2008

First prize for research on image compression using higher level perceptual redundancy.

IEEE Communications Chapter Prize • 2006

Awarded for MEng final year project.

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