Verified Expert in Engineering
David is a software engineer and an adjunct computer science professor at Stevens Institute of Technology in Hoboken, NJ. They've been involved in a number of startup businesses and worked in the financial services sector on high bandwidth/high transaction computing. They're an expert in C#/.NET and TypeScript, having used both since initial betas, and they do regular work with .NET Core and Node.js on the back end and React, Angular, Cordova, and Ionic on the front end.
Node.js, TypeScript, C#, Visual Studio Code (VS Code), Git
The most amazing...
...project I've helped build is a real-time trading exchange with a true stock order book for trading shares in teams during sporting events.
- Developed a greenfield mobile app in Ionic 2.
- Guided a UX consulting team to produce beautiful designs for our platform.
- Managed several part-time developers.
- Built a real-time trading engine to power our system, with a true stock market style order book and near-instantaneous settlement of trades.
- Helped pitch to a multitude of investors to raise capital for the company.
- Did the software architecture and design for the entire software platform.
Stevens Institute of Technology
- Taught introductory programming.
- Taught advanced systems programming for Unix environments.
- Taught advanced network stack code, including a reimplementation of the TCP/IP networking stack.
- Managed graduate students who wanted to pursue independent study.
- Built a real-time sales intelligence engine from the ground up.
- Wrote sophisticated back-end code that crawled various APIs such as Facebook and Twitter as well as scraping various internet pages to build rich profiles on companies.
- Built a real-time front end that integrated with the back end using SignalR/websockets to update company profiles on the user's screen as soon as new information was available.
- Fetched news from a variety of sources, such as Facebook feeds, RSS, and a news API, and stored it in Elasticsearch before generating feeds that were relevant to company profiles.
- Managed and mentored several developers.
- Developed a real-time vehicle tracking and dispatch system.
- Worked with Windows Azure cloud technology to use as back-end infrastructure in order to ensure the fulfillment of service level agreements.
- Used enterprise service bus middleware technology to handle all requests by users or vehicles.
- Developed hardware and software for a Linux-based embedded computer platform to put onto vehicles to report vehicle location, handle fare collection, and deliver information needed by passengers or operators.
- Managed interns responsible for large projects such as a system-wide administrative console intuitive for city administrators.
- Interfaced with the cell phone text message system to develop a short-code SMS mechanism for locating buses.
- Built a call-in system that used text-to-speech to read the vehicle location and ETA, after a senior citizen user study.
- Developed apps for iOS, Android, and Windows Phone 7 by leveraging both Java/Swift as well as Xamarin.
- Developed a real-time log file analysis engine for legacy bank applications.
- Created an automated testing framework for a trade processing loader, facilitating an upgrade to Geneva 7.6.
- Developed a “high-bandwidth” framework in C# in parallel to and compatible with a Java framework, avoiding garbage collection and other activities that could cause a performance lag.
- Implemented and managed a collaborative development environment, bringing teammates from Bangalore, the United Kingdom, and the United States together on one platform. Developed business processes for use of the environment.
- Created a scheduler system allowing business users unfamiliar with IT to schedule complex jobs.
- Created a wrapper around a buggy vendor tool to avoid a $15,000 redevelopment task by the vendor.
IT Integrations Consultant
World Travel Group
- Planned, tested, and integrated a full overhaul of IT solutions, replacing a dozen legacy servers with a virtualization platform.
- Outsourced email to Microsoft Hosted Services on an Exchange platform after a test period involving both Google Mail and Microsoft Exchange.
This app started in Angular and for a while we used Ionic as well as NativeScript. However, both turned out to not be mature enough platforms in that era to use.
IoT, Back End, Front End, and Embedded Linux for Methane Well Collection Mesh Networked Sensor/Monitoring Devices
Managed the project, working with relevant stakeholders to ensure that goals were met. I set up and managed a CI/CD system using CircleCI and set up and maintained Azure-based infrastructure to host the platform.
Developed the entire front-end web interface (TypeScript/React) for supervisors and a hybrid mobile application (TypeScript/Cordova/React) for employees.
Oversaw the lead back-end developer and acted as secondary developer on back-end code (TypeScript/Node.js/Express).
Custom CMS for Travel Agency
BallStreet Proof-of-Concept Apphttps://play.google.com/store/apps/details?id=com.ballstreettrading
FunnelFire Back-end Engine and Architecture
The engine was built in C# on a service bus architecture, with a series of ingestors running to pull data from a variety of data sources (Facebook API, Twitter API, CrunchBase, Lexis Nexis, Freebase, AngelList, web crawling, etc.) in response to messages and then to publish results as they were found back onto the bus. A company comparison algorithm then compares the company profiles found and, depending on match confidence, either merges the results into an existing company, creates a new company, or creates a potential merge for human verification via Amazon Mechanical Turk. News stories are fed through the same bus when discovered, where they land in an Elasticsearch database for future querying. A trie of all company names is stored in a proprietary self-designed database system, rapidly matching company names found in the article to help start off various push notifications and email alerts.
Teaching Computer Science at Stevens Institute of Technology
Real-time Vehicle Tracking System ("Treadmarks")
The entire platform was built on .NET, with Mono running on the buses and various workers written in C# and ASP.NET with SignalR powering the back end and web app.
Taxi Hailing System
Text message-based hails indicating where a rider was located would trigger a message to be sent out to the highest rated drivers that had sent a text-based command into the system reporting that they were "online." One of those drivers could reply reporting that they are going to accept the ride. If they were the first to reply and the request hadn't timed out, they would be texted back with the location of the rider and the rider would receive a confirmation text.
We then also used Twilio to allow the driver and rider to communicate via phone or text without releasing either of their phone numbers to one another. At the end of the ride, passengers were asked to rate their driver from 1 to 5, and low-rated drivers were deprioritized in the system for receiving text hails.
The platform was built in C# with heavy utilization of Twilio. Ultimately, Uber of course took off and Hoboken gave up trying to control the internet-based hailing of their taxis.
StackOverflow Top 2% Overall Rankinghttp://stackoverflow.com/users/172029/david-pfeffer
Guest Instructor at Webb Institute
.NET Core, Onsen UI, Ionic 3, Redux, Ionic 2, .NET, Angular, Express.js, PhoneGap, Ionic 4, MUI (Material UI), Electron, React Native, Ionic, AngularJS, ASP.NET MVC, NativeScript, ASP.NET Web API, Windows Presentation Foundation (WPF), Windows Communication Framework (WCF)
Node.js, Flexbox, React, React Redux, React Router, LocalStorage, REST APIs, RxJS, Google Maps API, Facebook API, D3.js, Twilio API, SignalR, Google Apps, Twitter API, SendGrid API
Cordova Plugins, CircleCI, Visual Studio, Adobe Photoshop, Amazon Simple Queue Service (SQS), AWS Simple Notification Service (SNS), Git, Microsoft Visual Studio, GitHub, Webpack, Webpack 4, Webpack 2, Webpack 3, Gulp, Fastlane, Trello, SendGrid, Amazon Simple Email Service (SES), Visual Studio App Center, RabbitMQ, Prism, Postfix, VMware, Microsoft Exchange, Hyper-V, Bitbucket, Mercurial
Concurrent Programming, REST, Parallel Programming, Reactive Programming, Functional Programming, Management, MapReduce, Spatial Databases, Agile, Model View Viewmodel (MVVM)
Mobile, Arduino, Android, Amazon Web Services (AWS), Azure, iOS, HockeyApp, Embedded Linux, Docker, Visual Studio Code (VS Code), Twilio, Google Cloud Platform (GCP), Ubuntu, Twitter, Linux, Windows Server, Bluetooth LE
MongoDB, Elasticsearch, Microsoft SQL Server, RavenDB, Amazon S3 (AWS S3), Couchbase, PostgreSQL, MySQL
Large Scale Distributed Systems, Concurrent Computing, Async.js, TCP/IP, Industrial Internet of Things (IIoT), Distributed Systems, Software Architecture, Cordova, PhoneGap Plugins, Pixel Perfect, Code Architecture, OOP Designs, SMTP, Multithreading, Concurrency, Software Design, APIs, DigiMesh, ZigBee, SVG, CSS3 Animation, Facebook, WebSockets, Email, Gentoo, SMS, Yocto
Master of Science Degree in Computer Science
Stevens Institute of Technology - Hoboken, NJ, USA
Bachelor of Science Degree in Computer Science
Stevens Institute of Technology - Hoboken, NJ, USA