Experts of Grey Systems
DENG, JULONG (January, 1933 – June 22, 2013), ✩✩✩✩✩
Professor, Huazhong University of Science and Technology, Wuhan, China.
Founder of Grey System Theory.
- Founded the Grey System Theory
- Proposed the first Grey Forecasting model
- Proposed the first Grey Relational Analysis (GRA) model
LIU, SIFENG (b. July 15, 1955), ✩✩✩✩✩
Distinguished Professor, Xi’an Polytechnic University, Xi’an, China.
He is widely respected as the world’s top expert on grey systems. He is primarily responsible for introducing the Grey System Theory to the international world. He authored the earliest known English textbooks on grey system theory. He is the honorary editor of International Journal of Grey Systems (IJGS), and patron of International Association of Grey Systems and Uncertainty Analysis (IAGSUA). He is one of the earliest students of grey system theory. He was trained by Deng Julong at Huazhong University of Science & Technology.
- Absolute Grey Relational Analysis (GRA) model
- Relative Grey Relational Analysis (GRA) model
- Synthetic Grey Relational Analysis (GRA) model
- Theory of Operators
- Feng, C., Liu, S., Dong, W., & Tao, L. (2024). A Reliability Evaluation Model for Complex Equipment Fusing General Uncertainty Variables. International Journal of Grey Systems, 4(2), 5-22. https://doi.org/10.52812/ijgs.103
- Javanmardi, E., Najafabadiha, A., Javanmardi, S., & Liu, S. (2025). A Novel Dynamic Grey SERVQUAL Approach to Quantifying Consumers’ Attitudes Towards Green Products. Journal of Grey System, 37(5).
- Fang, X., Nawaz, M., Liu, S., Zhang, W., & Hou, S. (2025). The Assessment of Barriers to Access eHealth Services for Elderly Persons with Disabilities Based on Hybrid Multi-Criteria Decision-Making Models. Journal of Grey System, 37(4).
- Nawaz, M., Liu, S., Xie, N., & Ramzan, B. (2025). Evaluation of barriers to artificial intelligence adoption: grey multi-criteria decision-making. Grey Systems: Theory and Application, 15(4), 732–754. https://doi.org/10.1108/GS-12-2024-0147
- Nawaz, M., Liu, S., Xie, N., Aetef, M., & Hanif, M. W. (2024). Evaluation of Barriers to Disabled Elderly’s Access to eHealth in China Using Grey Relational Analysis. Journal of Grey System, 36(5).
JAVANMARDI, EHSAN
Faculty, Nanjing University of Aeronautics and Astronautics, Nanjing, China.
He is well-known for his works on Grey Relational Analysis, Grey Systems Thinking and studying the philosophical foundations of the Grey Systems Theory. He is the editorial board member of International Journal of Grey Systems.
- Grey Systems Thinking
- Studying complex systems using Dynamic Grey Relational Analysis
- Javanmardi, S., Javanmardi, E., & Bucci, A. (2025). Quantifying drivers of virtual reality acceptance in tourism planning using a grey system theory-based approach. Journal of Hospitality and Tourism Insights, 8(4), 1308-1327. https://doi.org/10.1108/JHTI-04-2024-0367
- Javanmardi, E., Najafabadiha, A., Javanmardi, S., & Liu, S. (2025). A Novel Dynamic Grey SERVQUAL Approach to Quantifying Consumers’ Attitudes Towards Green Products. Journal of Grey System, 37(5).
- Najafabadiha, A., Wang, Y., Gholizadeh, A., Javanmardi, E., & Zameer, H. (2025). Fostering consumer engagement in online shopping: Assessment of environmental video messages in driving purchase intentions toward green products. Journal of Environmental Management, 373, 123637. https://doi.org/10.1016/j.jenvman.2024.123637
MA, XIN
Associate Professor, Southwest University of Science and Technology, China.
The 2nd Generation of the Grey Systems experts. He is well-known for his works on grey forecast models. He is the editorial board member of International Journal of Grey Systems.
- Proposed Conformable Fractional Grey Forecasting Model (breakthrough)
- Proposed Conformable Fractional Discrete Grey Model CFDGM (1,1)
- Proposed a new information priority accumulated grey model with hyperbolic sinusoidal term
- Wu, W., Ma, X., Zhang, H., Tian, X., Zhang, G., & Zhang, P. (2022). A Conformable Fractional Discrete Grey Model CFDGM (1,1) and its Application. International Journal of Grey Systems, 2(1). https://doi.org/10.52812/ijgs.36
- Tian, X., Wu, W., Ma, X., & Zhang, P. (2021). A new information priority accumulated grey model with hyperbolic sinusoidal term and its applications. International Journal of Grey Systems, 1(2), 5-19. https://doi.org/10.52812/ijgs.27
CAMELIA DELCEA
Professor, Bucharest University of Economic Studies, Romania.
The 2nd Generation of the Grey Systems experts. She is one of the leading European scholars of the Grey System Theory, and also one of the first women to study and apply the Grey System Theory. She authored the first English language monograph on the Grey System Theory from an international perspective. She is the Associate Editor of International Journal of Grey Systems.
- Application of Grey System Theory in Economics
- One of the first scholars to recognize the significance of Dynamic Grey Relational Analysis
- Delcea, C., Javed, S. A., Florescu, M.-S., & Cotfas, L.-A. (2023). 35 years of grey system theory in economics and education. Kybernetes. https://doi.org/10.1108/K-08-2023-1416
- Delcea, C., & Liviu-Adrian Cotfas, L.-A. (2025). Advancements of Grey Systems Theory in Economics and Social Sciences. Springer.
XIE, NAIMING
Professor, Nanjing University of Aeronautics and Astronautics, Nanjing, China.
The 2nd Generation of the Grey Systems experts. He is well-known for his works on grey forecast models. He was trained by Liu Sifeng at Nanjing University of Aeronautics and Astronautics. He is the editorial board member of International Journal of Grey Systems.
- Proposed Discrete Grey Forecasting Model
- Proposed a hybrid Verhulst-GM(1,N) model
- Khan, S., Bhatti, G. A., Nawaz, M., Xie, N., & Zhang, W. (2025). Forecasting ICT Service Export Trends Using Advanced Grey Models. The Journal of Grey System, 37(6), 66.
- Nawaz, M., Liu, S., Xie, N., Aetef, M., & Hanif, M. W. (2024). Evaluation of Barriers to Disabled Elderly’s Access to eHealth in China Using Grey Relational Analysis. The Journal of Grey System, 36(5).
WU, LIFENG
Professor, School of Management Engineering and Business, Hebei University of Engineering, Handan, China.
The 2nd Generation of the Grey Systems experts. He is well-known for his works on grey forecasting models. He is the editorial board member of International Journal of Grey Systems.
- Grey forecasting models
- Proposed Fractional Order Accumulation Operation
- Studied the Impact of COVID-19 on the Big Industrial Enterprises in Hebei
- Hu, S., Wu, F., & Wu, L. (2022). Impact of COVID-19 on the Big Industrial Enterprises in Hebei, China: Grey Forecast Perspective. International Journal of Grey Systems, 2(2), 13-17. https://doi.org/10.52812/ijgs.60
- Zhao, T., Pan, X., & Wu, L. (2025). Research on Loan Market Share Prediction Based on Grey Model and Exponential Smoothing Method. International Journal of Grey Systems, 5(1), 5–15. https://doi.org/10.52812/ijgs.107
ZENG, BO
Professor of Information Science, Chongqing Technology and Business University, Chongqing, China.
The 2nd Generation of the Grey Systems experts. He is well-known for his software development skills and works on grey prediction models. He is the editorial board member of International Journal of Grey Systems.
- Grey forecasting models
TAN, XUERUI
Dean, Shantou University Medical College.
President, 1st Affiliated Hospital of Shantou University Medical College.
One of the earliest students of grey system theory. He was trained by Deng Julong at Huazhong University of Science & Technology (PhD: 1994/09-1997/07)
- Application of Grey System Theory in Healthcare
MIERZWIAK, RAFAL
Faculty, Poznan University of Technology, Poland.
He is well-known for his works on studying the philosophical foundations of the Grey Systems Theory. He is a founding member of PSAGS (Polish Scientific Association of Grey Systems). He is the editorial board member of International Journal of Grey Systems.
- Philosophy of Theory of Grey Systems
OTHER SCHOLARS
- Bilal Ervural, Necmettin Erbakan University, Turkey
Selected publication: Comparative Analysis of E-Government Website Performances of European Countries Using Dynamic Grey Relational Analysis (EGETC, 2023). - Gol Kim, University of Sciences, DPRK
Selected publication: Novel Grey Interval Weight Determining and Hybrid Grey Interval Relation Method in Multiple Attribute Decision-Making (arXiv, 2012). - Haotian Xie, University of Hong Kong, China
Selected publication: Exploring the drivers of green supply chain management in the Chinese electronics industry: Evidence from a GDEMATEL–AISM approach (Cleaner Logistics and Supply Chain, 2023). - Halis Bilgil, Kayseri University, Turkey
Selected publication: China Total Energy Consumption Forecast with Optimized Continuous Conformable Fractional Grey Model (Alphanumeric Journal, 2024) - Muhammad Nawaz, Hunan University, China
Selected publication: Evaluation of barriers to artificial intelligence adoption: grey multi-criteria decision-making (Grey Systems: Theory and Application, 2025). - Yunchol Jong, University of Sciences, DPRK
Selected publication: Grey power models based on optimization of initial condition and model parameters (Grey Systems: Theory and Application, 2014)
(The list is incomplete, please revisit the page after few months. You can recommend entries by emailing to the EIC of IJGS)
Journals dedicated to Grey Systems
International Journal of Grey Systems
International Journal of Grey Systems (IJGS) is the first American journal dedicated to advancing the theory and practice of grey system theory as a new approach to soft computing and computational intelligence. The journal is interested in manuscripts that well-grounded in theory and can lead us in developing a scientifically rigorous body of knowledge of grey system theory. Innovative ideas for managing uncertain systems that can spark debate are also welcomed. As the first open access journal on grey system theory, it hopes to play a decisive role in the mainstreaming of grey system theory by improving the understanding and internationalization of grey system theory. The journal aims to facilitate exchanges between young and experienced academics, as well as between academics and practitioners, to help data analysts, problem solvers and decision-makers deal objectively with complex problems. Click here to submit paper to IJGS.
Grey Systems: Theory and Application
Grey Systems: Theory and Application (GSTA) is published by the International Association of Grey System and Uncertainty Analysis (GSUA). It was founded in 2011 by Professor Sifeng Liu and was then published by the Emerald Publishing Group Ltd. GSTA mainly publishes high-quality papers related to grey systems, uncertainty analysis and applications.
Under the strong leadership of Professor Liu Sifeng, the journal was indexed in the database of ESCI in 2017. Later, it was indexed in SCIE (2019), Scopus (2021) and EI Compendex (2022). According to the JCR 2022 report (Clarivate Analytics), the Grey Systems: Theory and Application is Q2 category journal, its IF is 2.188 and CiteScore is 3.5. The journal is subscription-based; thus, only its subscribers can access its content from EBSCO and Web of Science databases. However, there is an option to make the content Open Access at the cost of $3370. Each submission should be between 4500 and 6500 words in length and have a structured abstract. The peer-review process is double-blind, and the manuscript is usually sent to at least two reviewers.
According to its website, Grey Systems: Theory and Application mainly focuses on the latest research progress of grey system theory and uncertainty system analysis and its application research results in the fields of natural science, social science and engineering technology. It has gradually become a platform for grey system scholars from all over the world to share their latest research results. In addition, GSTA has published many original grey models and methods, which have been downloaded and cited by scholars from all over the world, and have produced a wide range of international influence. The scope of the submission should involve but not limited to:
- Grey number operation and grey algebra system
- Modeling mechanism and scope of GM model
- Grey relation analysis model
- Grey cluster evaluation and grey decision model
- Grey combination model
- Grey input-output and grey game model
- Gray control model and grey controller
- Grey system theory and its comparison with other uncertain system theories
- Sequence operators and spectral analysis
- Artificial intelligence, big data, cloud technology
- Complex equipment development management, technology innovation management
- Application Research of grey system theory in natural science, engineering technology and social science
The journal welcomes the research on the modeling and practical application of the Grey System Theory. In addition, it publishes hybrid methods that combine grey system theory with other methodologies to deal with uncertain information more successfully. In short, the journal encourages and follows the development of empirical techniques and their applications to real-world grey systems.
The Journal of Grey System
The Journal of Grey System (JGS) was the first English-language journal dedicated to the Grey System Theory. It was founded in 1989 by Professor Deng Julong and was then published by Sci-Tech Information Services & China Petroleum Industry Press. Today it is being published by Research Information Ltd (UK). Since the demise of Professor Deng, his pupil Professor Liu Sifeng has been the journal’s editor-in-chief.
It was the first English language journal of the Grey System Theory. The journal was indexed in the database of SCI/SCIE in 2007. According to the JCR 2022 report (Clarivate Analytics), the Journal of Grey System is Q4 category journal. The journal is subscription-based; thus, only its subscribers can access its content from EBSCO or Web of Science databases. Also, the journal has an Article Processing Charges (APC) of around $400. Each paper is of not more than 15 pages. The journal is one of the favorite outlets of the Chinese grey systems scholars, which can be confirmed by the number of publications by the Chinese authors on its pages. The peer-review process is double-blind, and the manuscript is usually sent to at least two reviewers.
According to its website, The Journal of Grey System promotes the development of the basic theory and practical application of grey systems. It wishes to build a professional forum for top scientists and practitioners from different countries to share their works on grey systems and publish new grey models and techniques along with their applications. The journal is a platform of the highest quality for scientists and practitioners to discuss and publish newly discovered issues on a wide range of topics related to grey systems. It publishes anything if it is somehow related to grey system theory. It provides an ideal opportunity to present, criticize, and discuss different grey models and techniques. Some areas of interest (but not limited to) are listed below:
- Grey mathematics,
- Grey sequence generators,
- Grey programming models,
- Grey input and output models,
- Grey control,
- Grey game theory,
- Grey relational analysis model,
- Grey forecasting models,
- Grey multiple criteria decision analysis,
- Grey machine learning.
The journal welcomes the research on the modeling and practical application of the Grey System Theory. In addition, it publishes hybrid methods that combine grey system theory with other methodologies to deal with uncertain information more successfully. In short, the journal encourages and follows the development of empirical techniques and their applications to real-world grey systems.
To submit papers to the journal, feel free to visit its website.
Organizations dedicated to Grey System Theory
- International Association of Grey Systems and Uncertainty Analysis
- Grey Systems – IEEE SMC
- Grey Systems Society of China
- Grey Systems Society of Pakistan
- Grey Systems Society of Turkey
- Polish Scientific Society of Grey Systems
- Chinese Grey System Association
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