Verified Expert in Engineering
George is a performance-oriented engineering leader with a substantial technology background and business proficiency. He specializes in designing and implementing large-scale distributed systems with a focus on performance and reliability. Throughout his career, George has consistently identified and managed the technology and operational risks with a strong sense of end-to-end ownership for complex software products.
Git, JetBrains, Linux
The most amazing...
...project I've worked on is a cloud infrastructure for multi-provider public and private cloud providers.
Senior Software Engineer
- Designed and implemented a distributed inference pipeline for supply/demand forecast using RedisTimeSeries as a feature store and Bloom filters to recover from restarts/crash failures.
- Identified improvements for the supply/demand forecasting, increasing the overall computational efficiency by six times.
- Designed and implemented a new algorithm for a computing heat map, a couriers’ tool showing high demand areas.
- Designed and implemented a Plasma extension for Ethereum blockchain. The project is supported by funding from the Ethereum Foundation.
- Reduced risk by using Pedersen commitment to preventing the operator from gaining information about transactions' values.
- Removed the linearizable requirement for a distributed system by designing inclusion proof-based on cryptographic accumulators.
- Reduced the memory usage from linear to logarithmic by incrementally building a block Merkle tree.
Software Engineer (Contract)
- Designed and implemented a content metadata processor microservice.
- Reduced the response time and increased the throughput by using write-through caching.
- Implemented a directed acyclic graph structure using continued fractions encoding for MongoDB collections.
Cloud Architect (Contract)
- Designed and implemented a workflow for creating cloud accounts configured following security requirements.
- Added support for OAuth2 and SAML for authentication/identity.
- Implemented a security auditor functionality for AWS and Google cloud accounts.
- Added support for an access control model for private/public cloud.
- Implemented SQS message de-duplication using a distributed Bloom filter.
Team Lead (Contract)
- Led a team of consultants in designing and implementing server-side functionality for Disney Identity.
- Created scrum stories from the business analysts’ requirements.
- Designed and implemented an integration with Facebook, Google+, PlayStation Network, and Xbox Live for Disney Identity.
- Implemented SSO support for Disney Identity.
- Added support for a rule engine used to evaluate country- and region-specific business logic. Implemented test and deployment methods for the business rules.
- Simplified the configuration management by writing a parser that extended JSON—allowing inheritance and marking fields required.
- Proposed, designed, and implemented a central authentication service using Python with Cassandra for session storage.
- Analyzed OpenID and OAuth2 protocols to determine which NoSQL solution to use for session storage.
- Managed the process of migrating all the Second Life websites to using the OpenID protocol for authentication.
- Designed and implemented the backup strategy for a Cassandra cluster.
- Designed and implemented a Cassandra cluster with Bootstrap using a dynamic DNS.
- Designed and implemented a financial engine used for calculating the order total with discounts, taxes, and shipping charges for the US and international destinations.
- Improved a solution for detecting unauthorized changes on production servers for Sarbanes-Oxley related systems. The system detected file system changes and reconciling them for more than 2,000 production servers using five hosts.
- Designed and implemented a large-scale, fault-tolerant authorization system that complies with and extends ANSI's RBAC standard.
- Proposed and implemented role-based access control (RBAC) as an authorization model that would allow the company to reach sustainable Sarbanes-Oxley compliance.
- Initiated a study group for design patterns and distributed systems.
Directed Acyclic Graph Using Continued Fractions Encoding
• Introduced a root node to handle cases not covered by the original paper (e.g., when a node doesn't exist in the system).
• Transformed the data structure to allow representation of a directed acyclic graph and to detect and prevent cycles from being introduced. The code uses several multi-way trees to represent multiple paths from the root node to leaf nodes and each sub-tree is stored as a MongoDB document.
• To ensure data consistency I used Redis locking for document updates. The reason for using Redis has to do with MongoDB concurrency model.
• Using the continued fractions encoding, I was able to ensure that read operations are executed in constant time in terms of the number of MongoDB queries.
It was implemented using AWS Simple Workflow Service and had several workflows for each provider. The back-end was implemented using Node.js and PostgreSQL.
SSL Cipher Fix for Cassandrahttps://issues.apache.org/jira/browse/CASSANDRA-3278
Cassandra Backup Manager
The distributed lock was implemented in Cassandra using a keyspace where the node performing a backup would write its identity. The value stored in the keyspace had a higher expiration period to ensure that the backup progresses in the presence of a node failure.
Erlang port for Berkeley DB HA
The Erlang port driver was running the same process as the Erlang VM and it kept track which node is was the master. All the reads were served from the local Berkeley DB storage while the write operations were forwarded to the master using Erlang's native remote procedure calls.
Order Evaluation Engine
Google Cloud API, Bottle.py, Node.js
Git, AWS SDK, Amazon Simple Queue Service (SQS), Subversion (SVN), JetBrains, RabbitMQ
Android, Linux, Google Cloud Platform (GCP), Blockchain, Amazon Web Services (AWS), Kubernetes, Oracle, OpenStack, Azure, Ethereum
Google Cloud, Cassandra, AWS SWF, PostgreSQL, MongoDB, Microsoft SQL Server, Redis, MySQL, LevelDB
Authorization, Caching, Distributed Systems, Large Scale Distributed Systems, Software Development, TCP/IP, Algorithms
Spring, Django, AWS HA, OAuth 2, gRPC
Master of Business Administration Degree in Business
University of Washington - Seattle, WA, USA
Bachelor's Degree in Control Engineering
Politehnica University of Bucharest - Bucharest, Romania