George Cristea
Verified Expert in Engineering
Algorithms Developer
George是一位以业绩为导向的工程领导者,拥有丰富的技术背景和业务熟练程度. 他擅长设计和实现大型分布式系统,重点关注性能和可靠性. Throughout his career, George始终以对复杂软件产品的端到端所有权的强烈意识来识别和管理技术和操作风险.
Portfolio
Experience
Availability
Preferred Environment
Git, JetBrains, Linux
The most amazing...
...我参与的一个项目是为多提供商公共和私有云提供商提供的云基础设施.
Work Experience
Senior Software Engineer
Postmates
- 使用RedisTimeSeries作为特征存储,使用Bloom过滤器从重启/崩溃故障中恢复,设计并实现了用于供需预测的分布式推理管道.
- 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.
Principal Engineer
Kyokan
- Designed and implemented a Plasma extension for Ethereum blockchain. The project is supported by funding from the Ethereum Foundation.
- 通过使用Pedersen承诺来防止运营商获取有关交易价值的信息,从而降低风险.
- 通过设计基于密码累加器的包含证明,消除了分布式系统的线性化要求.
- 通过增量构建块Merkle树,将内存使用从线性减少到对数.
Software Engineer (Contract)
iStreamPlanet
- Designed and implemented a content metadata processor microservice.
- Reduced the response time and increased the throughput by using write-through caching.
- 使用连分式编码实现了MongoDB集合的有向无环图结构.
Cloud Architect (Contract)
Disney
- 设计并实现了一个工作流,用于创建按照安全要求配置的云帐户.
- 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)
Disney
- 领导顾问团队设计和实现迪士尼身份的服务器端功能.
- 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.
- 增加了对用于评估特定于国家和地区的业务逻辑的规则引擎的支持. Implemented test and deployment methods for the business rules.
- 通过编写扩展json的解析器简化了配置管理——允许继承和标记所需的字段.
Senior Engineer
Linden Lab
- Proposed, designed, 并使用Python和Cassandra实现了一个中央身份验证服务,用于会话存储.
- 分析OpenID和OAuth2协议,以确定会话存储使用哪个NoSQL解决方案.
- 管理将所有Second Life网站迁移到使用OpenID协议进行身份验证的过程.
- Designed and implemented the backup strategy for a Cassandra cluster.
- Designed and implemented a Cassandra cluster with Bootstrap using a dynamic DNS.
Software Engineer
Amazon
- 设计并实现了一个财务引擎,用于计算带有折扣的订单总额, taxes, and shipping charges for the US and international destinations.
- 改进了一个解决方案,用于检测与Sarbanes-Oxley相关系统的生产服务器上未经授权的更改. 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.
- 建议并实现基于角色的访问控制(RBAC)作为授权模型,该模型将允许公司达到可持续的Sarbanes-Oxley合规性.
- Initiated a study group for design patterns and distributed systems.
Experience
Directed Acyclic Graph Using Continued Fractions Encoding
Work Done:
• Introduced a root node to handle cases not covered by the original paper (e.g., when a node doesn't exist in the system).
•转换数据结构,以允许有向无环图的表示,并检测和防止引入循环. 代码使用几个多路树来表示从根节点到叶节点的多条路径,每个子树都存储为MongoDB文档.
• 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, 我能够确保根据MongoDB查询的数量,在恒定的时间内执行读取操作.
Cloud Manager
它是使用AWS简单工作流服务实现的,每个提供商都有几个工作流. The back-end was implemented using Node.js and PostgreSQL.
SSL Cipher Fix for Cassandra
http://issues.apache.org/jira/browse/CASSANDRA-3278Cassandra Backup Manager
分布式锁在Cassandra中使用keyspace实现,其中执行备份的节点将写入其身份. 存储在keyspace中的值具有较长的过期时间,以确保在出现节点故障时继续进行备份.
Erlang port for Berkeley DB HA
Erlang端口驱动程序运行与Erlang VM相同的进程,它跟踪哪个节点是主节点. 所有的读操作都来自本地Berkeley DB存储,而写操作则通过Erlang的本地远程过程调用转发到主服务器.
Order Evaluation Engine
Skills
Languages
C++, Go, Python, Erlang (OTP), Java, JavaScript, Erlang, Solidity, SAML
Libraries/APIs
Google Cloud API, Bottle.py, Node.js
Tools
Git, AWS SDK, Amazon Simple Queue Service (SQS), Subversion (SVN), JetBrains, RabbitMQ
Paradigms
REST, Scrum
Platforms
Android, Linux, Google Cloud Platform (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
Other
Authorization, Caching, Distributed Systems, Large Scale Distributed Systems, Software Development, TCP/IP, Algorithms
Frameworks
Spring, Django, AWS HA, OAuth 2, gRPC
Education
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
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