Freelance Speech Recognition Engineer
2019 - 2019A US-based Tech Startup (via Toptal)- Created speech recognition models using custom neural networks with Keras, along with Baidu's DeepSpeech architecture via Tensorflow.
- Handled preprocessing of audio file input types (PCM/WAV) including conversions to and manipulations of MFCCs/spectrograms.
- Wrapped up processes for data uploading, model training, persistence and inference in RESTful APIs, with capabilities for complex versioning and live updates of training.
- Deployed and configured APIs to leverage GPUs for faster training/inference and a Celery distributed-task queue for training in parallel.
Technologies: Python, Keras, LibROSA, Celery, Connexion, Flask, MongoDBFreelance Data Scientist
2019 - 2019Kalepa Corporation (via Toptal)- Trained and evaluated various models for classifying text data using GloVe word representations, Bag of Words, and XGBoost among other ML/NLP techniques.
- Created and managed Amazon Mechanical Turk tasks for deriving labels for training classification, including detection of consistently inaccurate workers.
- Productionized inference process into PIP installable Python package.
Technologies: Python, Pandas, Gensim, XGBoost, Sklearn, MongoDB, SpaCyChief Information Officer
2019 - 2019Lawli Ltd- Led the technical direction for a UK government-funded legal AI app to help deliver the initial version of the product.
- Implemented initial NLP solutions in Python for providing document services at the heart of the app.
- Created the first version of an Angular 7 web app using Node.js and MongoDB.
- Conducted interviews to find people for the company's first development team to carry on my work.
Technologies: Angular 7, Node.js, Python, Gensim, RabbitMQ, WordPressFreelance NLP Expert
2018 - 2018Zugata (via Toptal)- Improved and developed a system for the key-phrase extraction from texts by using a trained ML classifier and a variety of extraction techniques (including those involving the statistical analysis of word collocations).
- Innovated a library which applies a dependency parser (including SpaCy or Stanford parsers) to texts and then extracts phrases according to common grammatical rules that have been automatically inferred from training texts (with the help of graph theory and NetworkX).
- Implemented frameworks that helped with research including the use of caches for extracted phrases and objects for persisting models with metadata to give consumer knowledge of how that model was formed.
- Created a Flask API for the output of results along with the user ability to specify the different methodologies.
- Enhanced an in-house evaluator of extractor performance accompanied by integration of traditional evaluators (Bleu/Rouge); also, set up cross-validation tests for classifier performance.
- Verified and advised on statistical/confidence tests for studies by a company which went toward a paper that won an award at KDD 2018.
Technologies: Python, NLTK, SpaCy, Sklearn, Flask, MySQL, Pandas, NumPyFreelance Data Scientist | Freelance Machine Learning Specialist
2017 - 2018A US-based Investment Management Firm (via Toptal)- Researched and tested prediction models with a Python stack using machine learning regressors and natural language processing techniques.
- Derived features from various sources including forming vector representations of words/documents using a Bag of Words model (with NLTK) and neural networks (with TensorFlow).
- Developed a configurable model backtesting (and backfilling) system making extensive use of various Pandas functionality.
- Improved the reliability of a Selenium-based framework for scraping websites to source data for model training, including improved logging and reports of nightly performance.
- Created a framework for mining and structuring of data from particular sections of PDF files.
- Enhanced and bug-fixed a React/Redux web app used for showing predictions.
Technologies: Python, Scikit-learn, TensorFlow, Pandas, MongoDB, Jupyter Notebook, AWS, React, NLTKFreelance Machine Learning Engineer
2016 - 2017Wedifique (via Toptal)- Implemented a collaborative filtering learning algorithm using Python libraries for use in a product recommendation system.
- Enabled a learning algorithm to be influenced by administrator suggestions when deciding feature weighings.
- Updated aspects of the main web app, where necessary on both the Node.js back-end and AngularJS front-end.
- Queried (using MongoDB) and derived data for use in user/trend analysis and to populate reports/graphs.
- Set up a web/worker multiple server infrastructures using AMQP with Heroku.
Technologies: Python, Scikit-learn, Pandas, NumPy, MongoDB, Node.js, AngularJSFreelance Full-stack Developer
2016 - 2016Swtch (via Toptal)- Created a geolocation web app's proof of concept using primarily AngularJS.
- Extensively used a Google Maps JavaScript API in an asynchronous manner, to create a map canvas, plot markers, as well as geocode them from addresses.
- Developed a complex user registration and booking system that was persisted to a PostgreSQL database using a pg-promise library in Node.js.
- Styled an app using Bootstrap so that it is responsive and can be used on a variety of devices.
- Implemented a RESTful API using Express.js and Node.js.
Technologies: AngularJS, Node.js, Bootstrap, Express.js, PostgreSQL, GulpAssociate Developer
2013 - 2016Goldman Sachs- Collaborated with a global market risk business to design and maintain a platform that produced a bank’s risk metrics.
- Used the firm's Python-like proprietary language to build and test a framework to collate big data sets and to automate the creation of stress test reports for regulators.
- Led the development team that produced an AngularJS web app and RESTful API to allow users to adjust risk measures and audit these changes.
- Conducted interviews of lateral hires and of interns/analysts for tech division.
- Assisted in integrating a platform into a new distributed computing framework, including occasional examination of the platform's core C++ code.
- Co-created a Java-based version system for report configurations which could be controlled via an AngularJS web app.
- Investigated machine learning methods for possible use in the department.
Technologies: AngularJS, JavaScript, Node.js, C++, Python, Java, Sass, DataTables, Sybase IQ, jQuery, Gulp, D3.jsAnalytics Developer
2010 - 2013RBS Markets & International Banking- Developed and maintained a .NET web-based application for analyzing and visualizing time series data for a range of financial products.
- Performed extensive regression testing and other analysis as part of the regular upgrades in pricing libraries the tool depended on.
- Implemented Agile methodologies in delivering several C# coding assignments to add new analytics.
- Trained the support and development teams around the globe including a trip to Singapore to facilitate this.
- Created a VBA tool for logging emails sent to the support inbox which then detected whether they had been responded to. This was then summarized in a management report.
Technologies: C#, SQL Server, ASP.NET, Oracle, VBAInside Licensing Specialist
2010 - 2010Microsoft- Automated the building of a spreadsheet which was compiled from various sources and also kept track of deal progress for a Munich-based licensing team.
- Created a tool using VBA to identify discrepancies between two customer pricing sheets (taking into account that entries may be present in both, but in different row locations).
- Presented these tools at team calls and wrote up documentation for them in English and German.
- Added new statistics for the account planning sheet including the data mining of past discounts given to customers.
- Assisted the licensing sales specialists with price and product migration queries.
Technologies: VBA, Excel
Python Developer in London, United Kingdom
Member since March 6, 2016
Oliver is a versatile data scientist and software engineer combining several years of experience and a postgraduate mathematics degree from Oxford. Career assignments have ranged from building machine learning solutions for startups to leading project teams and handling vast amounts of data at Goldman Sachs. With this background, he is adept at picking up new skills quickly to deliver robust solutions to the most demanding of businesses.
Oliver is now available for hire
Portfolio
- A US-based Tech Startup (via Toptal)Python, Keras, LibROSA, Celery, Connexion, Flask, MongoDB
- Kalepa Corporation (via Toptal)Python, Pandas, Gensim, XGBoost, Sklearn, MongoDB, SpaCy
- Lawli LtdAngular 7, Node.js, Python, Gensim, RabbitMQ, WordPress
Experience
- Python, 4 years
- JavaScript, 4 years
- Machine Learning, 3 years
- MongoDB, 3 years
- Pandas, 3 years
- Natural Language Processing (NLP), 2 years
- Data Visualization, 2 years
- Angular, 2 years
Availability
Part-time
Preferred Environment
Windows, Jupyter, PyCharm, Sublime Text, Git
The most amazing...
...application I've worked on allowed traders to visualize historical financial data, perform technical analysis and determine the relative value of securities.
Employment
Experience
- Oxford10 (Other amazing things)http://www.oxford10.com/
I worked as the president of the official young alumni community of Oxford University in the London region. My duties have included formulating and implementing social media strategy and website maintenance as well as heading a committee.
In my time on the committee, I have analyzed the data from Eventbrite and MailChimp to build a picture of our attendees and used it to inform our event strategy. Attendance has grown stronger as a result.
I have also revamped the website using WordPress (and the AccessPress Parallax theme). - From Solving Equations to Deep Learning: A TensorFlow Python Tutorial (Publication)TensorFlow makes implementing deep learning on a production scale a breeze. However, understanding its core mechanisms and how dataflow graphs work is an essential step in leveraging the tool’s power. In this article, Toptal Freelance Software Engineer Oliver Holloway demonstrates how TensorFlow works by first solving a general numerical problem and then a deep learning problem.
Skills
Languages
Python, TypeScript, CSS, HTML, SQL, C++, JavaScript, C#, Visual Basic for Applications (VBA), Sass, HTML5, R, CoffeeScript, JADE, JavaFrameworks
Angular, Flask, AngularJS, Angular Material, Bootstrap, Express.js, Jasmine, Django, ASP.NET, NUnitLibraries/APIs
Pandas, SpaCy, NLTK, Google Charts API, TensorFlow, RxJS, Scikit-learn, OpenCV, React, D3.js, REST APIs, Google Maps, Node.js, jQuery, NumPy, Matplotlib, Keras, AMQP, SQLAlchemy, Flask-RESTful, SklearnParadigms
Object-oriented Programming (OOP), Asynchronous Programming, Data Science, Agile Software Development, Test-driven Development (TDD)Storage
MongoDB, Microsoft SQL Server, PostgreSQL, MySQL, SybaseOther
Natural Language Processing (NLP), Machine Learning, Mathematics, Data Analysis, Data Engineering, Freelance, Data Modeling, Data Analyst, Freelance Developer, Data Scientist, Cryptography, Angular Bootstrap, Data Visualization, RESTful APIs, Statistics, Data, PDF, Google Material Design, LibROSATools
Gulp.js, AngularFire, PyCharm, Git, Mongoose, NPM, Sublime Text, Jira, Microsoft Visual Studio, TortoiseSVN, DataTables, Browserify, IntelliJ, CVS, MATLAB, Karma, GensimPlatforms
Jupyter Notebook, Amazon Web Services (AWS), Heroku, Firebase, Windows, Linux, Twilio, WordPress
Education
- Master of Science degree in Mathematics and the Foundations of Computer Science2008 - 2009University of Oxford - Oxford, England
- Bachelor of Science degree in Mathematics with a Study in Continental Europe2003 - 2007University of Bristol - Bristol, England
Certifications
- Deep LearningJANUARY 2019 - PRESENTDeeplearning.ai
- Machine LearningFEBRUARY 2016 - PRESENTStanford University via Coursera
- Financial Engineering in C++NOVEMBER 2013 - PRESENTCity, University of London (London, UK)
