1. At the Von Karman Institute For Fluid Dynamics
At VKI (1959-1961), I did mathematical work on Aerodynamic applications of Kinetic Theory of Gases under the direction of Professor Jean Smoldren. More specifically, my involvement was on: ” The study of Maxwell-Boltzmann Equation for weak interactions”, and ” The application of Lester Lee’s approximation method to the study of a weak unsteady shock wave (such as the one that would occur in a shock tube) by means of kinetic theory of gases”. In addition, I participated in the design of the first Subsonic Wind Tunnel of Greece. This project was done for the National Defense Research Center of Greece.
2. At the National Defense Research Center of Greece
At this center (1961-1963), I participated in the design and construction of a windmill prototype, done in connection to wind (Aeolic) energy utilization in Greece. This project was encouraged by the famous engineer Theodor Von Karman, who was interested to start it up in Greece.
3. At the STD Research Corporation, in Pasadena
During the summer of 1965, I did complicated analytical (mathematical) work on ” The generalized Ohm’s law for multicomponent plasma”.
4. At Burroughs Corporation
From 1965 to 1970, I was a research engineer and worked in the field of Design Automation. At Burroughs Corporation, I developed ALGOL based software, used to design computers using computers.
5. At the California Institute of Technology (Departments: of Aeronautics, and Chemistry) at CALTECH’s JPL
From 1970 to 1982, I was a Member of the Technical Staff at CALTECH’s JPL in the field of Orbit Determination and Spacecraft Navigation. At JPL, I developed the first functional description diagram of JPL’s Orbit Determination (OD) and Double Precision Trajectory (DPTRAJ) programs. The diagram included the “Mathematical basis and computer implementation” for both OD and DPTRAJ programs, and was instrumental in the design of several future planetary missions. For the Viking’75 Mission, assisted by three software engineers, I designed, implemented and documented a computer operating system, used for the automatic generation of UNIVAC 1108 computer run streams. These run streams, were necessary for monitoring and controlling key aspects of the orbital and trajectory operations of the VIKING 75 Mission. This operating system, was the first experiment in the usage of structured programming techniques carried out at JPL, and it was successfully utilized to facilitate the planning and execution of future space missions.
This system, in many ways, was an analogue of what Microsoft’s WINDOWS operating system is today with respect to the earlier developed DOS operating system.
During the period 1976 to 1979, I held a joint JPL – CALTECH appointment (as a Member of the Technical Staff and visiting faculty) at CALTECH’s department of Aeronautics. At CALTECH, I did research on the viscoelastic characterization of human intervertebral disc material, and offered seminars on the same subject. My research was supported by the United States Air Force Office of Scientific Research (AFOSR). According to an available letter of evaluation, written by the Chief Scientist (Dr. Leon Kazarian) of the Biodynamics and Bioengineering Division of the AFOSR, Aerospace Medical Research Laboratory, Wright- Patterson Air Force Base, OHIO, “Dr. Nick’s original investigations and creativity in biodynamics has formed the analytical and experimental foundation for other researchers to build upon”. In addition, I taught the course of Digital Image Processing at CALTECH’s department of Computer Science
During the period 1980 to 1982, I was a member of a NASA team involved in the design of a special “dual energy tomography experiment” used for the determination of calcium loss from the spine of the astronauts in weightless environment
During the period from 1985 to 1986, I was a Visiting Associate at CALTECH’s Chemistry Department. There, I offered several seminars on the Mathematical Aspects of Computerized Tomography, and attended lectures on Nuclear Magnetic Resonance (NMR).
During the last two decades, I conceived and pursued my idea to use wavelets for the processing of Magnetic Resonance Spectroscopic (MRS) signals obtained from tumors, in an effort to eliminate biopsy. My objective was, to develop an accurate, risk free, fast and economic non-invasive diagnostic tool for cancer detection, and to evaluate the currently used therapeutic methods. The results produced from this research were encouraging as it can be seen in the list of selected publications.
6. At the California State University Long Beach (CSULB), College of Engineering, Department of Electrical Engineering
In 1980, I joined the Department of Electrical Engineering at CSULB, as an Associate Professor and soon promoted to the rank of full Professor, of Electrical Engineering and appointed Director of the Digital Image Processing Laboratory. At CSULB, I and Professor Ellis Cumberbatch (from the department of mathematics of the Claremont Graduate University) originated and coordinated a “joint Ph.D. program”, in the fields of Applied Mathematics and Engineering. The program was managed jointly by CSULB and Claremont Graduate University, and was aimed to expose the participating engineers and applied mathematicians, from the very beginning of their studies, to industrial and social problems that needed practically useful solutions. The program is unique, because it is focused on rigorous mathematical, engineering, computer software, management, and research principles and addresses real life problems.
The success of the program, made it a model that other universities followed.
In addition, my wavelet related research was extended to other areas, such as the analysis of electromyograms (EMG), digital image processing and data compression. At CSULB, I remained until my retirement in 2004