Nikolaos Dourvas

Mr. Nikolaos Dourvas received his Diploma degree in Electrical and Computer Engineering (201?) from the Democritus University of Thrace (DUTh), Greece. In 201?, he received his M.Sc in Electrical and Computer Engineering from the Democritus University of Thrace, Greece. Currently, he is pursuing his Ph.D. in the area of ???, under the supervision of Prof. Sirakoulis.

Academic Qualifications

Master of Science (M. Sc.) on Microelectronics and Computer Systems

Democritus University Of Thrace (DUTh)
November 2015 – March 2017

Diploma in Electrical and Computer Engineering (D. Eng.)

Democritus University Of Thrace (DUTh)
October 2010 – July 2015

Publication List

Referred Journal Papers

  1. I. Gerakakis, P. Gavriilidis, N.I. Dourvas, I.G. Georgoudas, G.A. Trunfio, and G. Ch. Sirakoulis, “Accelerating Fuzzy Cellular Automata for Modeling Crowd Dynamics,” accepted for publication in Journal of Computational Science. 
  2. M. Mitsopoulou, N. Dourvas, and G. Ch. Sirakoulis, K. Nishinari, “Spatial games and memory effects on crowd evacuation behavior with Cellular Automata,” accepted for publication in Journal of Computational Science
  3. N. Dourvas and G. Ch. Sirakoulis, “A Inhibitor Sensitive, Collision Based Switching Like Transistor Element Using Periodic Traveling Waves and Cellular Automata,” International Journal of Unconventional Computing, vol. 13, no. 4-5, pp. 377-397, 2018. 
  4. V. Evangelidis, J. Jones, N. Dourvas, M.-A. Tsompanas, G. Ch. Sirakoulis and A. Adamatzky, “Physarum machines imitating a Roman road network: the 3D approach,” Scientific Reports, vol. 7, Article Number 7010, August 2017, (OPEN ACCESS https://doi:10.1038/s41598-017-06961-y). 
  5. N. Dourvas, G. Ch. Sirakoulis, and A. Adamatzky, “Cellular Automaton Belousov-Zhabotinsky Model for Binary Full Adder,” International Journal of Bifurcation and Chaos, vol. 27, no. 6, pp. 1750089, 2017. 
  6. N. Dourvas, G. Ch. Sirakoulis, and Ph. Tsalides, “A GPGPU Physarum Cellular Automaton Model,” Applied Mathematics & Information Sciences, vol. 10, no. 6, pp. 2055-2069, July 2017. 
  7. Th. Giitsidis, N. Dourvas, and G. Ch. Sirakoulis, “Parallel implementation of aircraft disembarking and emergency evacuation based on Cellular Automata,” International Journal of High Performance and Applications, first published June 2015, vol. 31, no. 2, pp. 134-151, 2017.
  8. N. Dourvas, M.-A. I. Tsompanas, G. Ch. Sirakoulis, and Ph. Tsalides, “Hardware Acceleration of Cellular Automata Physarum Polycephalum Model,” Parallel Processing Letters, vol. 25, 1540006 [25 pages], 2015.

Book chapters

  1. M.-A. I. Tsompanas, N. I. Dourvas, K. Ioannidis, G. Ch. Sirakoulis, R. Hoffmann, and A. Adamatzky, “Cellular Automata Applications in Shortest Path Problem,” in Shortest Path Solvers. From Software to Wetware, pp 199-237, published by Springer, 2018.
  2. N. Bitsakidis, N. I. Dourvas, S. Chatzichristofis, and G. Ch. Sirakoulis, “Cellular Automata Ants,” in Advances in Slime Mould Computing: Sensing and Computing with Slime Mould to be published by Springer, 2016.
  3. N. I. Dourvas, M.-A. I. Tsompanas, and G. Ch. Sirakoulis, “Parallel Accelaration of Slime Mould Discrete Models,” in “Advances in Slime Mould Computing: Sensing and Computing with Slime Mould,” pp. 595-618, published by Springer, 2016.

Conference Proceedings

  1. M. Madikas, M.-A. Tsompanas, N. Dourvas, G. Ch. Sirakoulis, J. Jones, and A. Adamatzky, “Hardware Implementation of a Biomimicking Hybrid CA,” in 13th International Conference on Cellular Automata for Research and Industry (ACRI 2018), pp. 80-92, Como, Italy, 17-21 September 2018.
  2. Ch. Semertzidou, N. I. Dourvas, M.-A. I. Tsompanas, A. Adamatzky, and G. Ch. Sirakoulis, “Introducing Chemotaxis to a Mobile Robot,” Artificial Intelligence Applications and Innovations (AIAI 2016) vol. 475, IFIP Advances in Information and Communication Technology, pp. 396-404, Thessaloniki, Greece, 16-18 September 2016.
  3. K. Konstantara, N. Dourvas, I. G. Georgoudas, and G. Ch. Sirakoulis, “Parallel Implementation of a Cellular Automata-based Model for Assisted Evacuation of Elderly People,” 24th Euromicro International Conference on Parallel, Distributed, and Network-Based Processing (PDP 2015), pp. 702-709, Heraklion Crete, Greece, 17-19 February 2016.
  4. N. Dourvas, G. Ch. Sirakoulis, and Ph. Tsalides, “GPU Implementation of Physarum Cellular Automata Model,” accepted for presentation in “1st International Symposium on Artificial, Biological and Bio-Inspired Intelligence (ABBII)” organized within the 12th International Conference on Numerical Analysis and Applied Mathematics (ICNAAM 2014), Rhodes, Greece, 22-28 September 2014.
Smart Bio-Inspired Electronic Systems With Memristive Devices
Supervisor: G. Ch. Sirakoulis
Study, Design, And Development Of Electronic Circuits, Inspired By Nature, With Learning Capabilities, Using Circuit Elements With Memory (Memristors)
Supervisor: G. Ch. Sirakoulis
Pedestrian and crowd dynamics are physical phenomena that are fundamentally characterized by non-linear complexity. In the same time, the need of modern way of living seeks for such dynamics real time modeling also enabling computationally efficient and affordable solutions for sake of safety and easiness of people located in gathering places all over the world. Towards this direction, Cellular Automata (CAs), a parallel computational model combining macro- and microscopic inherent attributes that could severely help with adequate modeling of the aforementioned dynamics, are one of the best compromises among different competing computational techniques. In order to overcome CAs deterministic nature, in this paper the incorporation of fuzzy logic principles in a CA model that simulates crowd dynamics and crowd evacuation processes, with the usage of a Mamdani type fuzzy inference system, is proposed. More specifically, basic concepts of fuzzy logic such as linguistic variables and if-then rules are attributed to the proposed CA model to preserve fuzzy consequents and fuzzy antecedents thus resulting in a realistic and rather efficient modeling approach. Furthermore, in the paper the implementation of fuzziness in CA dynamics is tackled with the acceleration of the proposed model through fully parallel execution on Graphics Processing Units (GPU). The GPU implementation of the fuzzy CA model is analyzed in full detail and stressed against CPU corresponding implementation resulting to an important speed up of fuzzy CA execution. This is further explored through the GPU applications of the fuzzy CA model in a real building, namely the museum `CONSTANTIN XENAKIS’, in Serres, Greece.
When it comes to emergency evacuations of a big number of individuals from a certain room or a building, it is crucial that they should be able to exit the under study place in a quick and safe manner. Nevertheless, crowd behavior can be affected from various factors, among which are the distance from the exit, the visibility of the exit, the density of the crowd and how uncomfortable the conditions are inside the room for the crowd. In this study, we propose an evacuation model, in order to achieve a computationally enhanced simulation, based on Cellular Automata modeling, coupled with a Spatial Game to solve conflict situations among the anxious crowd. Additionally, aiming to a more realistic model, we added not only topological, but also behavioral characteristics coupled with the incorporation of different moving velocities and memory features to the evacuees.
The reaction-diffusion (RD) models describe the change in the behavior of one or more chemical substances through space and time. The RD interaction can create waves of chemical concentration when the chemical systems used are far from equilibrium. The velocity and direction of those waves can be controlled and altered using excitable media or inhibitors. In particular, excitable media are spatially distributed systems characterized by their ability to propagate signals undamped over long distances, while inhibitors are used to reduce the propagation of those signals. The behavior of chemical oscillators are based on such media. The concept of this article is the proposal of a Cellular Automaton (CA) model which exploits the wave propagation characteristics on an excitable medium using inhibitors to create a switching element which is capable of distinguishing two binary states and present a form of amplification, like a basic transistor. In such a sense an unconventional chemical made device with properties similar to the conventional basic element of today’s electronics, namely CMOS transistor is conceived. Furthermore, and in order to properly explore the potential of the proposed device, we design a combination of two of those transistors to prove that they can reproduce Boolean algebra by creating two of the most well known and important component, i.e. the inverter NOT logic gate and the universal logic gate NAND.
Physarum Polycephalum is a single cell visible by unaided eye. This is a plasmodial, vegetative stage of acellular slime mould. This single cell has myriad of nuclei which contribute to a network of bio-chemical oscillators responsible for the slime mould’s distributed sensing, concurrent information processing and decision making, and parallel actuation. When presented with a spatial configuration of sources of nutrients, the slime mould spans the sources with networks of its protoplasmic tube. These networks belong to a family of planar proximity graphs. The protoplasmic networks also show a degree of similarity to vehicular transport networks. Previously, we have shown that the foraging behaviour of the slime mould can be applied in archaeological research to complement and enhance conventional geographic information system tools. The results produced suffered from limitation of a flat substrate: transport routes imitated by the slime mould did not reflect patterns of elevations. To overcome the limitation of the ‘flat world’ we constructed a three-dimensional model of Balkans. In laboratory experiments and computer modelling we uncovered patterns of the foraging behaviour that might shed a light onto development of Roman roads in the Balkans during the imperial period (1st century BC – 4th century AD).
The continuous increment in the performance of classical computers has been driven to its limit. New ways are studied to avoid this oncoming bottleneck and many answers can be found. An example is the Belousov–Zhabotinsky (BZ) reaction which includes some fundamental and essential characteristics that attract chemists, biologists, and computer scientists. Interaction of excitation wave-fronts in BZ system, can be interpreted in terms of logical gates and applied in the design of unconventional hardware components. Logic gates and other more complicated components have been already proposed using different topologies and particular characteristics. In this study, the inherent parallelism and simplicity of Cellular Automata (CAs) modeling is combined with an Oregonator model of light-sensitive version of BZ reaction. The resulting parallel and computationally-inexpensive model has the ability to simulate a topology that can be considered as a one-bit full adder digital component towards the design of an Arithmetic Logic Unit (ALU).
Scientists have been gaining inspiration from several natural processes and systems to find fine solutions in many complex hard to solve engineering problems for many years now. Nevertheless, most of these natural systems suffer from great amount of time to perform; thus, scientists are seeking for computational tools and methods that could encapsulate in a conscious way nature’s genius, dealing at the same moment with time complexity. In this conquest, Cellular Automata (CA) proposed long time ago by John von Neumann, can be considered as a promising candidate. CA have the ability to capture the essential features of systems in which global complicated behavior emerges from the collective effect of simple components, which interact locally. These characteristics are immanent in many natural systems; namely Physarum polycephalum,an amoeba, is such a system. This simple organism presents the intelligence of finding effective solutions to demanding engineering problems such as shortest path(s) problems, various graph problems, evaluation of transport networks or even robotic control. In this paper, we move forward by taking advantage of a Graphical Processing Unit (GPU) and the Compute Unified Device Architecture (CUDA) programming model, to make use of the CA inherit parallelism when biomimicking the behavior of P. polycephalum in maze, providing the ability to find the minimum path between two spots. In this way we are able to produce a virtual easy-to-access lab speeding up significantly the biological paradigm when modeled by CA implemented in General Purpose computing on Graphics Processing Units (GPGPU) environment.
In this paper we present a model based on the parallel computational tool of cellular automata (CA) capable of simulating the process of disembarking in a small airplane seat layout, corresponding to Airbus A320/ Boeing 737 layout, in search of ways to make it faster and safer under normal evacuation conditions, as well as emergency scenarios. The proposed model is highly customizable, with the number of exits, the walking speed of passengers, depending on their sex, age and height, and the effects of retrieving and carrying luggage. Additionally, the presence of obstacles in the aisles as well as the emergence of panic being parameters whose values can be varied in order to enlighten the disembarking and emergency evacuation processes are considered in detail. The simulation results were compared to existing aircraft disembarking and evacuation times and indicate the efficacy of the proposed model in investigating and revealing passenger attributes during these processes in all the examined cases. Moreover, we parallelized our code in order to run on a graphics processing unit (GPU) using the CUDA programming language, speeding up the simulation process. Finally, in order to present a fully dynamical anticipative real-time system helpful for decision-making we implemented the proposed CA model in a field programmable gate array (FPGA) device, and recreated the results given by the software simulations in a fraction of the time. We then compared and exported the performance results among a sequential software implementation, the implementation running on a GPU, and a hardware implementation, proving the consequent acceleration that results from the parallel CA implementation in specific hardware.
During the past decades, computer science experts were inspired from the study of biological organisms. Moreover, bio-inspired algorithms were produced that many times can give excellent solutions with low computational cost in complex engineering problems. In our case, the plasmodium of Physarum polycephalum is capable of finding the shortest path solution between two points in a labyrinth. In this study, we implement a Cellular Automata (CA) model in hardware, which attempts to describe and, moreover, mimic the behavior of the plasmodium in a maze. Beyond the successful implementation of the CA-based Physarum model in software, in order to take full advantage of the inherent parallelism of CA, we focus on a Field Programmable Gate Array (FPGA) implementation of the proposed model. Namely, two different implementations were considered here. Their difference is on the desired precision produced by the numerical representation of CA model parameters. Based on the corresponding results of the shortest path in the labyrinth,the modeling efficiency of both approaches was compared depending on the resulting error propagation. The presented FPGA implementations succeed to take advantage of the CA’s inherit parallelism and improve the performance of the CA algorithm when compared with software in terms of computational speed and power consumption. As a result, the implementations presented here, can also be considered as a preliminary CA-based Physarum polycephalum IP core which produces a biological inspired solution to the shortest-path problem.
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