GE Medical Systems,
Data Critical Corp.
Algorithm Engineer, 1994 - 1997
Analyzed, developed and implemented various algorithms such as error correction, encryption, compression and encoding schemes.
Designed and implemented Reed-Solomon Forward Error Correction. Analyzed communication channel determined type and strength of correction needed. Eliminated and improved efficiency within Data Through Paging Project (DTP).
Design and optimization of specialized integer digital filters: Adaptive QRS-retaining Low-Band Pass, 50/60 Hz line noise and Baseline drifts. FDA approval for use in RhythmStat XL ECG system.
Developed various unique, specialized methods for recognition and digital extraction of ECG waveforms from within low resolution fax images.
Responsible for redesign, optimization, maintenance, and documentation of file transfer protocol specific to DTP project.
Constructed detailed arguments and prepared support documents for DTP patent application. Patent awarded 1997.
Forward Error Correction
Researched, designed, implemented, tested and analyzed Reed-Solomon Forward Error Correction. Binary data, including applications, ECG and ordinary image files, are encoded, packetized and sent via wireless paging. Since paging is a one way data transfer, the need for data reliability is crucial. Reed-Solomon codes provide relatively small overhead while providing strong error correction, and minimizing or eliminating the need for data packets to be resent. Performed statistical error analysis to determine the strength and capabilities required. Designed and implemented C routines utilizing abstract algebra ( Galois and Galois polynomial fields ) and advanced linear algebra necessary to perform the error correction. Integrated code into DTP file transfer protocol. Conducted tests to analyze code performance. Incorporated in ECGStat, PalmVue (HP), and SecurePage Products. Decoding and encoding are performed on PC-compatible machines and decoding on HP200LX palmtop computers and windows laptops.
Communication Protocol : Data Through Paging (DTP)
Responsible for redesign, optimization, maintenance and documentation of DTP file transfer protocol. Designed new methods and encoding algorithms to significantly reduce transmission overhead (25%). Constructed detailed arguments and explanations for DTP patent application. Responsible for design, implementation and integration of any additional features, such as error correction and SMS (Short Messaging Service) compatibility.
ECG Tools and Algorithms :
Compression
Developed and analyzed various specialized ECG compression methods for transmission of ECG waveforms. Due to small sample rate, length and range, third party compression packages proved to be inadequate, thus specific algorithms were developed to provide satisfactory compression gains.
Image/Waveform Detection
Project to recognize and digitally extracted ECG waveforms within poor and low resolution fax images. Standard digitalization techniques result in noise and pixilation causing high error rates and unacceptable waveforms, rendering the data useless for medical applications. Thus various specialized algorithms were developed to overcome these problems.
Noise Filters (DSP)
Development and optimization of specialized integer digital filters: Adaptive QRS-retaining Low Band Pass, 50/60 Hz line noise and Baseline drifts for the FDA approved RhythmStatXL system. Filters were developed in C for use with both the RhythmStat Windows NT server, and the PSION client RhythmStat application. Standard low pass filters blunt the important QRS peaks in ECGs. Since ECG characteristics vary in size and frequency, the filter was adaptive, conforming to the specific characters of each waveform, learning peak QRS height and duration. The filter developed retains the original peaks while removing other undesirable background noise and baseline drift. Real time adaptive noise filters were implemented and optimized for integer arithmetic for use on the PSION.
Real-time ECG/Patient Java Monitor
Developed a multi-threaded Java applet/application to acquire and display multiple lead ECG data directly from Marquette patient monitors and CardioPager servers over TCP/IP networks. Due to burst packet nature of the incoming data, complex adaptive buffering techniques were developed to produce smooth output rates to the screen.
CardioPager Pager Transmitter Module
A TCP/IP to Pager communications Windows-NT service module. Provides transmission and verification of ECG waveforms to wireless Pagers in a hospital setting, in conjunction with data acquisition modules, core server modules, and administration applications. Paging transmitter modules are attached on a TCP/IP network through Lantronix TCP/IP - serial bridges. Paging receivers are also similarly attached to the network, allowing for send/receive loop tests.
Other Projects :
Java ECG Viewer Applet - Stream live and stored ECG files via the web.
Cardio Server Web admin ISAPI DLL - team development project.
Data Acquisition Module - Additional feature and project maintenance.
Motorola Advisor Pager Programming - Reverse engineered Motorola Advisor Pagers encoding-cipher. Developed algorithm to encode and decode pager password programming.