Dmitry Liksonov

Personal ltd. business (E.I.) registered in France, providing services to clients worldwide (easy service EXPORT in/out EU) Oct 2023-Mar 2025: Freelance: focus on R&D, AUDIO DSP algorithms (MatLab/Octave/C) & SW (in C): auralization, spatial audio, HRTF rotation, CROSSTALK cancellation, FIR/FFT/WOLA, freq. response flattening, tests/measurements/calibration, etc Feb-Aug 2023: Contractor in DSP/SW/digital audio for Arkamys: focus on ANC/FxLMS, audio effects porting in C for AD Audio SHARC, ARM & other processors, OPTIMIZATION [SIMD, math, algorithm, etc], audio framework integration, profiling, testing (on simulator, embed. HW & PC), etc Jan 2021-Sept 2022: Contractor (remote) for Philips (Digital Audio Research), mostly busy with the IVAS project, working on implementation, optimization & testing of DSP code in C/C++, plus experimental work on spatial audio rendering. Main results: -Reverberation code (Jot reverberator) porting completed -Code optimization: large reduction of overall computational load (4..5 times lower) & of memory usage -Initialization code (in C) with configuration processing -Porting of minimum-phase FFT filter design into C, with optimizations -Memory handling adapted to requirements for embedded target -Code structure, quality & compliance improved -Extensive code testing done, stability & robustness improved -Proximity mixing audio effect C code adapted to new requirements -Experiments & applied research work on audio rendering -Distortion/artifacts in HRTF convolution noticeably reduced Sept 2019-June 2020: Contractor for 7-Sensing SW (Belgium, 75% remote): productisation of DSP audio algorithms for wireless earbuds. Tasks & achievements: -Reference code development in C (DSP algorithm porting from Python) -Time-domain DSP blocks implementation (IIR & FIR filters, etc) -Frequency-domain DSP blocks implementation (FFT, DRC, frequency response modification, noise reduction, source fusion, etc) -C code optimization -Code testing & debugging

Worked for the client company A-Volute on the following topics: - Implementing new audio effects (adaptive noise reduction, beam forming, etc.) in C++ code for a DSP with code optimization at various abstraction levels (HW-specific including SIMD, implementation, applied math/algorithm). - Porting the existing audio effects for a DSP embedded application with limited resources (re-writing the C++ code with a different approach and using an entirely different, light architecture). Tasks and achievements: a) Code development in C++ (object-oriented with particular restrictions) for Xtensa Hi-Fi 3 processor with Hi-Fi-3 SIMD instruction set b) Re-architecting the audio processing chain, creating a new, light SW architecture + more compact & efficient C code base better adapted for a DSP with limited resources c) Time-domain DSP blocks implementation (IIR and FIR filters, dynamic range compressor, multi-band amplitude limiter, etc.) d) Frequency-domain DSP blocks implementation (FFT, frequency response correction, noise reduction, beam forming, voice morphing, power limiting at resonance frequencies, etc.) e) Optimizing digital signal processing code for reduced memory and processor cycles usage: good performance achieved with very limited resources on the target DSP (as compared to a PC). Optimizations included: - In-depths study and modifications of the initial algorithm (Matlab code from R&D team) - Math optimizations (polynomials and other approximations, re-arragements of calculations, etc.) - Various C code level optimizations - Vectorization by SIMD (Hi-Fi3 instruction set) - Porting certain parts of code to fixed-point f) Configuration & control interface implementation on the DSP side g) Encapsulation of audio processing blocks into stand-alone modules, and their integration into audio framework h) Successful embedded software profiling and testing (on simulator & on target hardware) Note: a recommendation letter is available on request regarding this project

Worked for the Porsche AG client company on EMBEDDED SW OPTIMIZATION for an adaptive cruise control system (in particular on improving the efficiency of the vehicle behavior simulation module). Main focus on: - Mathematical optimizations (interpolation, simplification, re-arrangement of math operations, moving constant expressions out of loops and sub-functions, etc.) - Simulation model improvements - C++ code optimizations - Using SIMD for ARM NEON in order to improve efficiency (implemented with C++ intrinsics) - SW testing (including writing new automated test scripts) - Detailed performance & resource usage profiling. Worked for the Bosch GmbH client company on embedded SW development and optimization (automotive multimedia applications). Tasks included: - Code development in C++ (object-oriented) for i.MX6 processor (ARM Cortex-A9) under embedded Linux - Code development in C (low-level, SPI interfacing, etc) for another ARM processor (Zynq) under a custom RTOS - Code development in C++ for PC (apps for image processing, data obfuscation/encryption/decoding, various SW prototypes, etc) - Computational algorithm development for fast computing of video projection geometry - Designing a new algorithm for adaptive mesh generation, aimed at improving image/video rendering quality - Design and improvement of algorithms for camera distorsion compensation - Algorithm design and implementation for image mask storage, transmission and handling - Design of a new algorithm for vertex shader management. - Code optimization for speed (C++, intrinsics), including SIMD coding for NEON co-processor using floating-point and fixed-point computing - Detailed profiling of optimized C++ code on embedded target - Optimizing C++ code for vertex/fragment shaders management - Applied research on new techniques for improving video rendering quality and performance

Worked on the following main tasks/goals: 1. Develop the embedded HW for PET scanner, mainly for fast digital signal processing (at 200 MHz sampling rate) of multi-channel sensor signals. This included: - Mixed and digital circuit design - Corresponding with a subcontractor company regarding PCB routing and manufactoring - PCB unit testing - HW integration tests. 2. Develop signal processing algorithms for PET scanner. Included: - Custom algorithm for time-domain processing of SiPM sensor signals, aiming to improve time resolution - New mathematical model of scintillator crystal coupled with SiPM sensors (presented also in the USA at the NSS/MIC congress, publication available) - New algorithm for optimal (min RMS error) detection of gamma ray photon interaction position in the scintillator crystal - New algorithm for filtering valid/invalid pulses - Improvements to image reconstruction algorithms. 3. Develop the embedded SW for PET scanner. Included : - Writing initial reference code for the PC (in C) - Embedded SW development in C for a TI tms320 fixed-point DSP processor - Implementation/porting of DSP algorithms for the processing of high-frequency signals from SiPM sensors - Code optimization - Programming on-board interfaces (SPI, I2C, UART) - Software testing at various levels 4. Perform combined (integration) testing of the embedded system: analogue circuits + mixed (A+D) HW + embedded SW (in C) + control SW (in Python and C++ on a PC). 5. Perform tests and measurements using PET scanner prototypes and radioactive sources 6. Propose improvements and innovations (intellectual property) for the PET scanner 7. Develop mathematical models and simulation codes (in C++) enabling to model the behavior of various PET scanner components (LYSO chrystals, SiPM, DSP system).

Tasks included: - Embedded software development in C for the dsPIC33 - Hardware design of a system based on a dsPIC33 microcontroller - Interfacing with external sensors, data readout and storage. - Embedded SW for collected sensor data handling and transmission to a PC. - Writing simulation/data processing code for the PC (in C++) and performing data processing, including some statistical analysis. - Interfacing the embedded system with GPRS/GSM modules. - Testing and validation

Worked on the development of measurement equipment, and on computer simulation of physical phenomena. Work included: - HW design (mostly circuits and boards for connecting actuators and sensors). - Sensor signal acquisition/recording using ADCs and LabVIEW - DSP applied to sensor signals - Signal processing and simulation software development in C - Modelling & simulation (mostly by finite elements applied to fluids and solids dynamics). - Testing at various levels: HW, SW, the whole system. - Performing various measurements (mostly vibration and viscoelasticity) using both commercial and internally designed (made-to-measure) equipment - Writing some scientific papers on the work performed

Embedded HW/SW engineer working on the development of electomagnetic flowmeters. Main focus on: - Embedded SW in C for MSP430 - DSP algorithm design and implementation - Embedded HW design - Computer simulation (multi-physics, including magnetic and electric fields, liquid flow etc). - Testing of HW/SW components and of the whole flowmeter prototype