Prabhas Chongstitvatana


Professor Prabhas Chongstitvatana works at Chulalongkorn University's Department of Computer Engineering. In 1992, he received his Ph.D. from Edinburgh University's artificial intelligence department in the United Kingdom. He conducts research in the fields of computer architecture, robotics, bioinformatics, quantum computing, and evolutionary computation.  He is a senior adviser for the Thai Robotics Society, a senior member of the Thai Academy of Science and Technology, and a lifelong member of the Thailand Engineering Institute.  From 2012 to 2013, he presided over the ECTI Association of Thailand.  The National Research Council of Thailand named him a "National Distinguished Researcher" in 2009.  Constructing a quantum computer is his current passion.

office:  Faculty of Engineering, Chulalongkorn University, Eng. Build 4, Floor 18, room 12, tel 02-2186982.

email :  prabhas dot c at chula dot ac dot th
follow his twitter: @prabhas_c

Research Highlight

Publication List

Top ten most cited articles

Quantum Computing (most recent)

This work proposes a quantum-assisted compact genetic algorithm that uses a quantum amplitude amplification technique in the selection process. In addition to using elitism mechanics where a single best candidate solution is kept to drive the probability vector, the amplitude amplification also acts as a mutation operator which, with high probability, enforces the constraint that the newly generated candidate is a feasible solution. We apply this algorithm to the traveling salesman problem of on IBM Qiskit simulator. We show space and time complexity analysis based on the quantum circuit model.

Kamonluk Suksen, K., Benchasattabuse, N., Chongstitvatana, P., "Compact Genetic Algorithm with Quantum-Assisted Feasibility Enforcement," ECTI Trans on Computer and Information Technology, Vol.16, No.4, December 2022 (local copy) (link to journal article)

Keywords: Quantum computing, Grover’s search algorithm, compact genetic algorithm (cGA)

Hardware Compact Genetic Algorithm

Genetic Algorithm is an optimization technique based on probabilistic search.  It is a sub-field of Artificial Intelligence. It is widely used in industry because it is simple and effective.  Hardware Compact Genetic Algorithm is an embodiment of the algorithm into digital circuits, achieving 1000 times speed up over the software incarnation.
Keywords: Compact Genetic Algorithm, Hardware implementation.
Aportewan and Chongstitvatana, 2001 #5

Coincidence Algorithm

Coincidence Algorithm is an optimization algorithm for combinatorial problems.  There are many uses in industry such as scheduling assembly line, inventory control, logistics etc.  A unique characteristic of Coincidence Algorithm is its use of the negative examples to improve the quality of the solution.  Presently, negative-correlation learning has been acknowledge as one of the new promising method in optimization and machine learning. 
Keywords: Combinatorial optimization, scheduling, negative learning.
Wattanapornprom, W., Olanviwitchai, P., Chutima, P. and Chongstitvatana, P., 2009 #8

Compact Genetic Algorithm on Quantum computers

This work presents an example of programming a quantum computer. The compact genetic algorithm is used as a target as it is powerful and popular method in evolutionary computation.  This paper demonstrates the enhancement in terms of solution quality and speed introduced by quantum computation. The simulation of quantum computing is carried out for solving a problem using the compact genetic algorithm. The exponential speed up over a classical computer is demonstrated.
Keywords: Genetic algorithms, Compact Genetic Algorithms, Quantum Computers.
Yingchareonthawornchai, S., Aporntewan, C., and Chongstitvatana, P., 2012 #14

Public Talk

previous talk ( 2001 -- 2019)

Optimizing hard problems with quantum computers, keynote, IEEE Int Conf on Big data and smart computing, Feb 18-21, 2024, Bangkok, Thailand.
Impact of Generative AI on Education,  invited talk, Nakornnayok, 24 January 2024
Quantum Computing and Artificial Intelligence, keynote speech at Int. Conf. on Advanced Information Science and System, 3 Dec 2023, Thailand ( video at Youtube)
Solving Optimisation Problems with a Quantum Computer, P. Chongstitvatana and K. Suksen, invited seminar at National University of Singapore, 29 November 2023. (abstract and biodata)
AI impact to society (poster of the event), round table talk, at Int. Joint Conf. on Computer Science and Software Engineering (JCSSE), Thailand, 28 June 2023.
Solving Hard optimization problems with Quantum Computer, invited talk at The 4th Materials Research Society of Thailand Int. Conf., 28 Feb - 4 March 2023, Ubon Ratchatani, Thailand (abstract)
Quantum Optimization, invited talk at Int Conf on Emerging Technologies for Communications (ICETC 2022), Tokyo, Japan, 30 November 2022, presented by Kamonluk Suksen  (abstract)
Introduction to Programming for Quantum Computer, workshop at Joint Conference of Computer Science and Engineering, Bangkok, 22 June 2022    ( video )
Future Technology, talk to students at Wat Suthiwararam school, Bangkok, 17 June 2022
Quantum Computer and Its Impact to Industry, keynote speaker at National Conference on Science and Technology, Bangkok, 16 June 2022
Quantum Circuits for Compact Genetic Algorithm, talk at Prince of Songkla University, Phuket campus, Consortium of Asian researchers on computing, Phuket, Thailand, 27 May 2022.
From Research to Innovation, talk at Faculty of Science, Chandrakasem Rajabhat University, Thailand, 19 May 2022, (complimentary topic Writing a good research paper)
Creative research, round panel discussion at Int Computer Science and Engineering Conference, Thailand, 20 November  2021.
Write a good research paper, talk at the workshop "Manuscript to paper" at National Science and Technology Development Agency, Thailand, 5 October 2021.
Publish your work, invited talk at Prince of Songkla University, Phuket campus, workshop on research writing, 19 September 2020.
Facebook Live "Quantum Computing", host Prof. Thanaruk, 30 Aug 2020.

Old teaching

Undergraduate teaching

2190250 Computer Architecture and Organization NEW
2110316 Programming Languages Principles NEW
2110101 Introduction of Programming: Python

Graduate teaching

2110600 Introduction to BME 2023: Is AI the future?
2110714 Digital Systems 2022
2110682 Embeded and Real Time System
2110607 Research Method (CS weekend)   Conference proceedings
2110793 Advanced topic in digital systems


Programming: Python  (2023)


Research grants and awards

I am currently active in the field of Evolutionary Computation, Bioinformatics and Quantum computing.  My research activities are associated with Intelligent System Laboratory (ISL) in the department of computer engineering, Faculty of engineering, Chulalongkorn University. ISL  has ties with University of Tokyo, Japan and the school of informatics, Edinburgh University, Scotland.


COIN: Coincidence Algorithm for combinatorial optimisation
Fake news detection


RISC-V interpreter with detailed control sequences
TX version 1.0  (a very small processor)
S2 version 1 processor
S2 Chip simulator
S30 multicore processor
4B processor, a simple processor that can be implemented with basic elements
CPU 1001  simulator on the web
Natural Graphic Processing Unit


Recursive programming with list  NEW
Som-language  (som v5.1  64-bit vm) (refresh)
Lowpower programming
RZ language
The power of emulation: Retro programming
Mini SQL Where clause parser
R1 concurrent system  (1994-1995)
Self generating compiler  (under construction)
Threaded Language     
Retro Basic (exercise in compiler class 2018)


IOI  Computer Olympic
Support my book "The essence of computer system engineering"

Publication List

publication statistics

Top ten most cited articles

My former graduate students (and their theses)

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last update 22 February 2024