Professor Sifeng Liu, Ph.D., a distinguished professor at Northwestern Polytechnical University. He was a professor at NUAA, DMU and HAU respectively. Dr Liu has selected into the long-term project of national major talent programs of China, honorary fellow of WOSC, and senior fellowship of Marie Skłodowska-Curie actions of the EU. He is serving as the founding director of CGSS at NPU, the founding president of IAGSUA, the founding editor of GS, and the editor-in-chief of JGS and two book series on Grey Systems one in English (Springer-Nature) and the other one in Chinese (Science Press). He was the founding director of IGSS at NUAA and the founding president of GSSC. His publications has been cited 51631 times with an H-Index of 95 in Huezhi Scholar and ranking first in the list of the highly cited authors in the field of system science by Baidu Scholar. He has listed in top 2% scientists of the world by Stanford University. On the 7th of September, 2019, then German Chancellor Merkel praised Prof. Liu's work as "profoundly influencing the world". In 2023, Prof. Liu won the Global Excellence Award by GSSP. In 2024, he was selected as one of the top 0.05% Highly Ranked Scholar-Lifetime of the world by Scholar GPS.

• Introduction.- Characteristics of grey system theory.- Grey Numbers and their Operations.- Sequence Operators and Grey Data Mining.- Grey Relational Analysis Models.- Grey Clustering Evaluation Models.

Professor Sifeng Liu, Ph.D., a distinguished professor at Northwestern Polytechnical University. He was a professor at NUAA, DMU and HAU respectively. Dr Liu has selected into the long-term project of national major talent programs of China, honorary fellow of WOSC, and senior fellowship of Marie Skłodowska-Curie actions of the EU. He is serving as the founding director of CGSS at NPU, the founding president of IAGSUA, the founding editor of GS, and the editor-in-chief of JGS and two book series on Grey Systems one in English (Springer-Nature) and the other one in Chinese (Science Press). He was the founding director of IGSS at NUAA and the founding president of GSSC. His publications has been cited 51631 times with an H-Index of 95 in Huezhi Scholar and ranking first in the list of the highly cited authors in the field of system science by Baidu Scholar. He has listed in top 2% scientists of the world by Stanford University. On the 7th of September, 2019, then German Chancellor Merkel praised Prof. Liu's work as "profoundly influencing the world". In 2023, Prof. Liu won the Global Excellence Award by GSSP. In 2024, he was selected as one of the top 0.05% Highly Ranked Scholar-Lifetime of the world by Scholar GPS.

• Introduction.- Characteristics of grey system theory.- Grey Numbers and their Operations.- Sequence Operators and Grey Data Mining.- Grey Relational Analysis Models.- Grey Clustering Evaluation Models.

Professor Sifeng Liu, Ph.D., a distinguished professor at Northwestern Polytechnical University. He was a professor at NUAA, DMU and HAU respectively. Dr Liu has selected into the long-term project of national major talent programs of China, honorary fellow of WOSC, and senior fellowship of Marie Skłodowska-Curie actions of the EU. He is serving as the founding director of CGSS at NPU, the founding president of IAGSUA, the founding editor of GS, and the editor-in-chief of JGS and two book series on Grey Systems one in English (Springer-Nature) and the other one in Chinese (Science Press). He was the founding director of IGSS at NUAA and the founding president of GSSC. His publications has been cited 51631 times with an H-Index of 95 in Huezhi Scholar and ranking first in the list of the highly cited authors in the field of system science by Baidu Scholar. He has listed in top 2% scientists of the world by Stanford University. On the 7th of September, 2019, then German Chancellor Merkel praised Prof. Liu's work as "profoundly influencing the world". In 2023, Prof. Liu won the Global Excellence Award by GSSP. In 2024, he was selected as one of the top 0.05% Highly Ranked Scholar-Lifetime of the world by Scholar GPS.

• Introduction.- Characteristics of grey system theory.- Grey Numbers and their Operations.- Sequence Operators and Grey Data Mining.- Grey Relational Analysis Models.- Grey Clustering Evaluation Models.