Jim Callahan Email & Phone Number

Cleveland, Ohio, Us

Boston, Massachusetts, Us

Boston, Ma, Us

Responsible for company-wide technical direction and system design leadership. Led a team of Senior Staff Engineers who acted as TAs (Technical Advisors) to each of the 5 company verticals in partnership with Senior Engineering Managers and Technical Leads. Ran frequent design reviews with TAs in which Technical Leads presented proposals for novel technical approaches and evaluated the architectural, performance, security and regulatory issues involved. Worked in close cooperation with company leadership, Product, Engineering Managers, and Technical Leads to find practical solutions to difficult challenges that maximize positive customer outcomes.Led a process with TAs and staff engineers to design, plan and socialize:- The evolution of front-end to back-end communication from direct service CRUD-style APIs to indirect communication via an API Gateway based on a unified GraphQL model and customer intent driven APIs. This decoupling accelerates engineering velocity and lays the foundation for major refactoring of BE systems without disrupting FE progress.- The modernization of back-end systems across all teams from largely a single monolithic service toward a microservice architecture with decoupled event-based asynchronous service communication using Kafka.- Initiated and led a project called Backplane to abstract business logic and persistence models from communication mechanisms. Backplane is a shared API platform which provides request/event transport, authentication/authorization, validation, coercion, error handling and observability for services. This allows the creation of fully functional services which follow best practices within minutes.Took initiative to understand the core issues, lead discussions and build consensus among opposing sides in difficult technical debates. This resulted in solutions satisfactory to all parties and a refocusing of efforts to implement those solutions.

Led the team responsible for core Trading Infrastructure and Broker Dealer Operations. The trading infrastructure was a Command Query Responsibility Segregation (CQRS) system of asynchronous streaming services written 100% in Clojure and built on top of Kafka, Kubernetes and AWS. This innovative architecture allowed for highly scalable, efficient and robust processing of trades initiated by our customers. Responsible for team planning, setting priorities, leading tech breakdowns and design, mentoring team developers as well as significant individual contributions to our Clojure codebase. One of the core technology leaders which contributes to cross-team decisions involving performance, developer/QA tools, testing, DevOps and cloud infrastructure.Parkside was acquired by Nubank.

Member of elite company wide research lab directly under the CTO with a focus on Investment Banking and Wealth Management. Met with top banking leadership and principals to understand their core issues in order to propose creative technical solutions leading to new opportunities. Lead projects related to IPOs, securing cloud for sensitive client data, immutable data and highly scalable distributed back office computation and machine learning related to tying NLP to trends in market data.

New York, Us

Lead a team of developers in the Platform group responsible for all of the backend infrastructure of the Company. Hired as part of a modernization effort at the company to rethink all backend systems to take advantages of new technologies and hardware capabilities. The Platform group's philosophy going forward is firmly based on an immutable functional style of programming for creating highly scalable distributed systems using languages like Scala and Clojure.

Toronto, On, Ca

Research advanced techniques for visualizing big-data, especially time varying graphs of millions of nodes and edges. Involved in exploring new techniques for data analysis involving machine learning and natural language processing on cluster computing. Implemented and continually improving a graphics library for visualization (ScalaGfx) which combines high-level Scala API with low-level OpenGL high performance back-end.

Toronto, On, Ca

Design and implement interactive visualization applications which communicate the practical utility of innovations in natural language processing and machine learning with respect to news, legal, financial and social networking data.

Founded Temerity Software in 2004. Directs product design and development. Temerity is a software and service provider in the visual effects and digital production industry. Our solutions and products are developed to allow a greater focus on the creative process of bringing ideas to life. We develop tools that automate processes, create efficiencies and most of all free up more production resources.Our flagship product is Temerity Pipeline, the industry's first complete production control application designed for the film, television and game industries. Pipeline increases productivity and studio profitability by providing seamless control over distributed processing of jobs, revisions and storage management. Studio pipelines are managed through one environment allowing artists to spend more being creative instead of dealing with production issues.IP acquired by Sony Interactive Entertainment.

Worked on a number of broadcast commercial projects many of which in association with Rhinoceros Visual Effects & Design. Duties included writing custom VEX OPs and VMantra shaders for Houdini, MEL scripting and C++ based Maya Plugins and shaders for RenderMan compliant renderers.

Miramar, Wellington, Nz

Worked on preproduction and production of "Fellowship of the Ring". Responsibilities included developing the tools and techniques needed to generate natural phenomena related effects.Designed and implemented BlackBox, a distributed particle simulator capable of utilizing large numbers of processors in parallel for each simulation step. BlackBox was used on simulations involving hundreds of millions of particles while maintaining practical compute times. Algorithms implemented for BlackBox included the combustion process as well as fluid dynamic properties of fire and smoke. Also created Nimbus, a fully RenderMan compliant volumetric renderer. Nimbus can read an extended form of RIB file which supports the BlackBox particle format as a procedural primitive and other volumetric extensions. In addition Shading Language based shaders are also supported via a standalone compiler supported nearly all SL constructs as well as volumetric extensions.

Designed and implemented Hookah, an integrated fluid dynamics and volume rendering system. This software was used to simulate and render nearly all gaseous phenomena in "Armageddon" as well as the "Sand Worm" sequence of "Mission to Mars". Hookah uses a unique approach based on a hybrid of particle system and cell based CFD techniques which allows efficient computation of the interaction of very large numbers of particles in a physically accurate manner. The software was multi-threaded and designed to utilize SGI Origin servers with 16 processors and 16 GB of RAM but could be scaled down to run on desktop workstations as well. Lead artist on "Armageddon" after completion of the software. Sole animator on four of the most difficult shots of the film and as well as lead on nearly all other shots involving Hookah. Preproduction R&D on the design and technique for the "Sand Worm" effect in "Mission to Mars".

Primary design and implementation of real time character behavior code for the Aladdin VR Adventure. Wrote a collection of stand-alone character animation tools for use with Alias PowerAnimator including a facial animation scripting system, a real time animation playback tool and a translator from Alias PowerAnimator to the proprietary VR engine used to run Aladdin. Other projects include, a set of custom shaders and post processing tools for a "illustrated look" rendering technique, procedural shaders for ocean waves, a realistic star field generator using astronomical data and an efficient low polygon count tessellator for NURBS surfaces.Modeling and animation on a number of projects including "Aladdin's VR Adventure", "Hercules", "Villains" and the "ABC Afternoon Toy Story" spots.

High end computer graphics consulting firm based in New York City. Performed a wide variety of services ranging from programming to creative design. Clients included: Warner Brothers, Walt Disney, Alias America, Acclaim, Bloomberg, Eidolon Inc, and The American Museum of Natural History. Founded Cygnus while attending the college of Architecture at the University of Florida.