George Cristea
Verified Expert in Engineering
Algorithms Developer
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.
Portfolio
Experience
Availability
Preferred Environment
Git, JetBrains, Linux
The most amazing...
...project I've worked on is a cloud infrastructure for multi-provider public and private cloud providers.
Work Experience
Senior Software Engineer
Postmates
- 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.
- 确定供应/需求预测的改进, 将整体计算效率提高6倍.
- 设计并实现了一种新的计算热图算法, 显示高需求地区的快递工具.
Principal Engineer
Kyokan
- 设计并实现了以太坊区块链的Plasma扩展. 该项目由以太坊基金会提供资金支持.
- 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.
软件工程师(合约)
iStreamPlanet
- 设计并实现了一个内容元数据处理器微服务.
- 通过使用透写缓存减少了响应时间并提高了吞吐量.
- Implemented a directed acyclic graph structure using continued fractions encoding for MongoDB collections.
云架构师(合同)
Disney
- Designed and implemented a workflow for creating cloud accounts configured following security requirements.
- 增加了对OAuth2和SAML的身份验证/标识支持.
- 为AWS和Google云帐户实现了安全审计功能.
- 增加了对私有/公共云访问控制模型的支持.
- 使用分布式Bloom过滤器实现SQS消息重复数据删除.
Team Lead (Contract)
Disney
- Led a team of consultants in designing and implementing server-side functionality for Disney Identity.
- 根据业务分析师的需求创建scrum故事.
- 设计并实现了与Facebook的整合, Google+, PlayStation Network, 和Xbox Live的迪士尼身份.
- 为Disney Identity实现了SSO支持.
- Added support for a rule engine used to evaluate country- and region-specific business logic. 为业务规则实现了测试和部署方法.
- Simplified the configuration management by writing a parser that extended JSON—allowing inheritance and marking fields required.
Senior Engineer
Linden Lab
- 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.
- 设计并实现了Cassandra集群的备份策略.
- 使用动态DNS设计并实现了一个带有Bootstrap的Cassandra集群.
Software Engineer
Amazon
- Designed and implemented a financial engine used for calculating the order total with discounts, taxes, 以及美国和国际目的地的运费.
- Improved a solution for detecting unauthorized changes on production servers for Sarbanes-Oxley related systems. 系统检测到超过2个文件系统更改并进行协调,000台生产服务器使用5台主机.
- 设计并实现了一个大规模的, 符合并扩展了ANSI的RBAC标准的容错授权系统.
- Proposed and implemented role-based access control (RBAC) as an authorization model that would allow the company to reach sustainable Sarbanes-Oxley compliance.
- 发起了一个设计模式和分布式系统的研究小组.
Experience
用连分式编码的有向无环图
Work Done:
•引入根节点来处理原始论文未涵盖的情况(例如.g.,当某个节点在系统中不存在时).
• 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.
•为了确保数据的一致性,我使用Redis锁来更新文档. 使用Redis的原因与MongoDB的并发模型有关.
•使用连分式编码, I was able to ensure that read operations are executed in constant time in terms of the number of MongoDB queries.
Cloud Manager
It was implemented using AWS Simple Workflow Service and had several workflows for each provider. 后端是使用Node实现的.js and PostgreSQL.
SSL密码修复卡桑德拉
http://issues.apache.org/jira/browse/CASSANDRA-3278Cassandra 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.
用于Berkeley DB HA的Erlang端口
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
Education
工商管理硕士学位
美国华盛顿大学西雅图分校
控制工程学士学位
布加勒斯特Politehnica大学-布加勒斯特,罗马尼亚
Skills
Libraries/APIs
Google Cloud API, Bottle.py, Node.js
Tools
Git, AWS SDK, Amazon Simple Queue Service (SQS), Subversion (SVN), JetBrains, RabbitMQ
Languages
c++, Go, Python, Erlang (OTP), Java, JavaScript, Erlang, Solidity, SAML
Paradigms
REST, Scrum
Platforms
Android, Linux, 谷歌云平台(GCP), Blockchain, Amazon Web Services (AWS), Kubernetes, Oracle, OpenStack, Azure, Ethereum
Storage
Google Cloud, Cassandra, AWS SWF, PostgreSQL, MongoDB, Microsoft SQL Server, Redis, MySQL, LevelDB
Frameworks
Spring, Django, AWS HA, OAuth 2, gRPC
Other
Authorization, Caching, Distributed Systems, 大规模分布式系统, Software Development, TCP/IP, Algorithms
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