Chen Lin, Developer in University City, MO, United States
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Chen Lin

Verified Expert  in Engineering

Quantitative Analyst and Software Developer

Location
University City, MO, United States
Toptal Member Since
April 14, 2022

Chen is an expert C++ software engineer specializing in developing and implementing risk models for the past 12 years. He has worked for Wells Fargo, Cardinal Financial, and Flight Safety International. Chen's current focus is developing machine learning risk models using Python and PySpark. He has also built 3D visual tools, CAD software, and back-end communication protocols for financial data. Chen has a master's degree in mathematics and a bachelor's degree in computer engineering.

Portfolio

Wells Fargo
Python, Spark, SAS, Risk Modeling, GitHub
Cardinal Financial Company
JavaScript, Python, SQL, Microsoft Access, Visual Studio Code (VS Code)
Wells Fargo
C++, SAS, Models, Mortgages, CVS, Subversion (SVN), Python, Bash...

Experience

Availability

Part-time

Preferred Environment

Windows, Vim Text Editor, Skype, Slack

The most amazing...

...experience was co-creating a profitable eCommerce business with a partner.

Work Experience

Lead Quantitative Analyst

2020 - PRESENT
Wells Fargo
  • Developed statistical and machine learning models in support of credit risk portfolios.
  • Supported implementation and documentation of production models.
  • Assisted in developing custom modeling tools used in model development and implementation processes.
Technologies: Python, Spark, SAS, Risk Modeling, GitHub

Business Systems Engineer

2019 - 2020
Cardinal Financial Company
  • Improved the design of an internal commissions application.
  • Initiated an effort to develop an API to centralize back-office processes.
  • Supported the development of a custom mortgage origination system for Cardinal Financial.
Technologies: JavaScript, Python, SQL, Microsoft Access, Visual Studio Code (VS Code)

Senior Financial Analyst

2010 - 2019
Wells Fargo
  • Led the implementation of a retail home lending credit risk model from SAS to C++ on a grid-enabled platform.
  • Designed and developed auxiliary model processes to automate subsequent model updates and validations.
  • Partnered with quantitative modelers to review and provide feedback on the model's correctness.
  • Mentored junior analysts on model structures and implementation processes.
  • Presented oral and written reports to internal and external auditing partners on model implementation correctness.
  • Assisted financial analysts in understanding the model drivers, calculations, and the impact of valuations on the model.
Technologies: C++, SAS, Models, Mortgages, CVS, Subversion (SVN), Python, Bash, Windows PowerShell, Cygwin, SQL

Software Engineer

2008 - 2010
Flight Safety International
  • Designed a flexible authentication scheme to correctly control the features, expiration dates, and other access levels in the company's software products.
  • Developed airport modeling tools in C and C++ used by modelers to create realistic airports with Presagis Creator, 3D CAD software for flight simulation modeling.
  • Created many smaller Perl and Python scripts for ad hoc development and installation tasks.
Technologies: C++, CAD, CVS, Perl

Streamlined Model Implementation

Using a composite pattern to streamline model implementation. The previous model implementation, written in C++, was rather static with a lot of boilerplate code when a driver for the model was added. In addition, there were many manual processes involved in adding and building new inputs and outputs, new drivers, and test and validation cases.

While working on the model implementation for 5+ years, I developed a good sense of the structures and improvements needed for the model. I also developed several improvements by using a composite pattern:

1. Cleaned up the codebase from around 50,000 lines of code to roughly 2,000.

2. Provided the option to easily add, remove, and update inputs, outputs, and driver details without recompiling the model.

3. Optimized the key loop in the model to speed up its performance by using the composite pattern to consolidate similar evaluation logics that were previously littered across many CPP files.
2005 - 2007

Master's Degree in Mathematics

Washington University - St. Louis, MO, USA

1999 - 2003

Bachelor's Degree in Computer Engineering

Washington University - St. Louis, Missouri, USA

Tools

CVS, Cygwin, GitHub, Microsoft Access, CAD, Subversion (SVN), Vim Text Editor, Skype, Slack

Languages

Python, C++, SAS, Java, JavaScript, Bash, SQL, Perl

Frameworks

Spark, Windows PowerShell

Platforms

Visual Studio Code (VS Code), Windows

Other

Mortgages, Analysis, Risk Modeling, Models, Patterns, Algorithms

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