### Research topics

##### Areas of interests

Multi-agent optimization, Optimal control, Convex analysis, Set-valued analysis, Alexandrov geometry, Nonlinear Analysis

##### Current research

Bilevel optimization, Nash equilibrium problem, Multi-leader-follower game, Optimization modeling in energy and environmental applications, Convex analysis in nonlinear data spaces

### List of Publications

- J. Abubakar,
**P. Chaipunya,**P. Kumam,**“Iterative method for split equilibrium problem and minimization problem via conjugate gradient method,”**Journal of Computational and Applied Mathematics, 2023, 429, 115191. - S. Termkaew,
**P. Chaipunya**, F. Kohsaka,**“Infinite product and its convergence in CAT(1) spaces,”**Mathematics, 11(8), 1807. - S. Channark, P. Kumam,
**P. Chaipunya**, W. Jirakitpuwapat,**“Progressive iterative approximation method with memory and sequences of weights for least square curve fitting,”**Science and Technology Asia, 2023, 28(1), pp.90–107. - S. Termkaew,
**P. Chaipunya**, D. Gopal, P. Kumam,**“A contribution to best proximity point theory and an application to partial differential equation,”**Optimization, to appear. **P. Chaipunya**, N. Chuensupantharat, P. Sanguansuttigul,**“Graphical Ekeland’s variational principle with a generalized -distance and a new approach to quasi-equilibrium problems,”**Carpathian Journal of Mathematics, 2023, 39(1), pp.95–107.- K. Khammahawong,
**P. Chaipunya**, P. Kumam,**“An inertial Mann algorithm for nonexpansive mappings on Hadamard manifolds,”**AIMS Mathematics, 2023, 8(1), pp.2093–2116. - A.H. Ibrahim, P. Kumam, M. Sun,
**P. Chaipunya**, A.B. Abubakar,**“Projection method with inertial step for nonlinear equations: Application to signal recovery,”**Journal of Industrial and Management Optimization, 2023, 19(1), pp.30–55. - S. Channark, P. Kumam, J. Martinez-Moreno,
**P. Chaipunya**, W. Jirakitpuwapat,**“Generalized and optimal sequence of weights on a progressive-iterative approximation method with memory for least square fitting,”**Mathematical Methods in Applied Sciences, 2022, 45(17), pp.11013–11030. - K. Khammahawong,
**P. Chaipunya**, K. Sombut,**“Approximating common fixed points of nonexpansive mappings on Hadamard manifolds with applications,”**Mathematics, 2022, 10(21), 4080. - A.B. Abubakar, P. Kumam, A.H. Ibrahim,
**P. Chaipunya**, S.A. Rano,**“New hybrid three-term spectral-conjugate gradient method for finding solutions of nonlinear monotone operator equations with applications,”**Mathematics and Computers in Simulations, 2022, 201, pp.670–683. - K. Khammahawong,
**P. Chaipunya**, P. Kumam,**“Iterative algorithms for monotone variational inequality and fixed point problems on Hadamard manifolds,”**Advances in Operator Theory, 2022, 7(4), 43. - S. Yadav, D. Gopal,
**P. Chaipunya**, J. Martinez-Moreno,**“Towards strong convergence and Cauchy sequences in binary metric spaces,”**Axioms, 2022, 11(8), 383. - P. Dechboon, P. Kumam,
**P. Chaipunya**,**“An inertial projection-like method for solving a generalized Nash equilibrium problem,”**Science and Technology Asia, 2022, 27(3), pp.109–120. - K. Paponpen, K. Sucharitpongpan, N. Termsaithong,
**P. Chaipunya**,**“The implementation of steering angle estimation on miniature Raspberry Pi-based autonomous car,”**ICIEA 2022 Proceedings, 2022, pp.1037–1042. - P. Dechoon, P. Kumam,
**P. Chaipunya**, N. Boonyam,**“A generalized F-contraction mapping for coupled fixed point theorems and an application to a two-person game,”**Journal of Nonlinear Functional Analysis, 2022, 11. - P. Dechboon, P. Kumam,
**P. Chaipunya**,**“An alternative extragradient method for a vector quasi-equilibrium problem to a vector generalized Nash equilibrium problem,”**in: Studies in Systems, Decision and Control, 2022, 427, pp.27–47. - M.M. Yahaya, P. Kumam, A.M. Awwal,
**P. Chaipunya**, S. Aji, S. Sani,**“A new generalized quasi-Newton algorithm based on structured diagonal Hessian approximation for solving nonlinear least-squares problems with application to 3DOF planar robot arm manipulator,”**IEEE Access, 2022, 10, pp.10816–10826. **P. Chaipunya**, F. Kohsaka, P. Kumam,**“Monotone vector fields and generation of nonexpansive semigroups in complete CAT(0) spaces,”**Numerical Functional Analysis and Optimization, 2021, 42(9), pp.989–1018.- A.B. Abubakar, P. Kumam, M. Malik,
**P. Chaipunya**, A.H. Ibrahim,**“A hybrid FR-DY conjugate gradient algorithm for unconstrained optimization with application in portfolio selection,”**AIMS Mathematics, 2021, 6(6), pp.6506–6527. - K. Khammahawong, P. Kumam,
**P. Chaipunya**, J. Martinez-Moreno,**“Tseng’s methods for inclusion problems on Hadamard manifolds,”**Optimization, 2022, 71(5), pp.4367–4401. - K. Khammahawong, P. Kumam,
**P. Chaipunya**, S. Plubtieng,**“New Tseng’s extragradient methods for Pseudomonotone Variational Inequality Problems in Hadamard Manifolds,”**Fixed Point Theory and Algorithms for Sciences and Engineering, 2021, 2021(1), 5. - K. Khammahawong, P. Kumam,
**P. Chaipunya**,**“Splitting algorithms for equilibrium problems and inclusion problems on Hadamard manifolds,”**Numerical Functional Analysis and Optimization, 2021, 42(14), pp.1645–1682. - U. Deepan, P. Kumam,
**P. Chaipunya**,**“Sparse pinball twin parametric support vector machine,”**Thai Journal of Mathematics, 2021, 19(2), pp.607–622. - U.B. Yusuf,
**P. Chaipunya**, P. Kumam, S. Yoo-Kong,**“Composition of quantum operations and their fixed points,”**in: Data Science for Financial Econometrics, N. Ngoc Thach et al. (Eds.), 2021, Springer, Cham, Switzerland. - S. Termkaew, P. Kumam,
**P. Chaipunya**,**“Splitting proximal algorithms for convex optimizations over metric spaces with curvature bounded above,”**Thai Journal of Mathematics, 2021, 19(2), pp.693–711. - P. Dechboon, P. Kumam,
**P. Chaipunya**, S. Dhompongsa,**“Fuzzy equilibrium via best proximity pairs in abstract economies,”**Soft Computing, 2021, 25(12), pp.7899–7905. - I. Ahmed, E.F.D. Goufo, A. Yusuf, P. Kumam,
**P. Chaipunya**, K. Nonlaopon,**“An epidemic prediction from Analysis of a combined HIV-COVID-19 co-infection model via ABC-fractional operator,”**Alexandria Engineering Journal, Vol.50 (3), 2021. - K. Khammahawong, P. Kumam,
**P. Chaipunya**,**“Splitting algorithm of common solutions between equilibrium and inclusion problems on Hadamard manifolds,”**Linear and Nonlinear Analysis, Vol.6 (2), 2020, pp.227–243. - K. Khammahawong, P. Kumam,
**P. Chaipunya**,**“On the convergence of splitting algorithm for mixed equilibrium problems on Hadamard manifolds,”**Journal of Mathematical Chemistry, Vol.58 (4), 2020, pp.799–815. - A. Padcharoen, P. Kumam,
**P. Chaipunya**, Y. Shehu,**“Convergence of inertial modified Krasnoselskii-Mann iteration with application to image recovery,”**Thai Journal of Mathematics, Vol.18 (1), 2020, pp.126–142. - N. Pakkaranang, P. Kumam, P. Cholamjiak, R. Suparatulatorn,
**P. Chaipunya**,**“Proximal point algorithms involving fixed point iteration for nonexpansive mappings in CAT() spaces,”**Carpathian Journal of Mathematics, Vol.34 (2), 2018, pp.229–237. - W. Jirakitpuwapat,
**P. Chaipunya**, P. Kumam, S. Dhompongsa, P. Thounthong,**“New methods of construction of cartesian authentication codes from geometries over finite commutative rings,”**Journal of Mathematical Cryptography, Vol.12 (3), 2018, pp.119–136.. - A. Padcharoen, P. Kumam, P. Saipara,
**P. Chaipunya**, “**Generalized Suzuki type -contraction in complete metric spaces,”**Kragujevak Journal of Mathematics, Vol.42 (2018), pp.419–430. - A. Padcharoen,
**P. Chaipunya**, P. Kumam,**“Existence theory in modular metric spaces,”**in: Advances in Mathematical Inequalities and Applications, P. Agarwal et al. (Eds.), 2018, Birkhäuser, Singapore. - P. Dechboon, P. Sa Ngiamsunthorn, P. Kumam,
**P. Chaipunya**,**“Berinde-Borcut tripled best proximity points with generalized contraction pairs,”**Thai Journal of Mathematic, Vol.16 (2018), pp.287–305. **P. Chaipunya**,**“Variational inequalities under the global NPC condition,”**in: New Trends in Analysis and Geometry, A.H. Alkhaldi et al. (Eds.), 2018, Cambridge Scholars Publishing, UK.- K. Wongkum, P. Kumam, Y.J. Cho, P. Thounthong,
**P. Chaipunya**,**“On the generalized Ulam-Hyers-Rassias stability for quartic functional equation in modular spaces,”**The Journal of Nonlinear Science and Applications, Vol.10 (2017), pp.1399–1406. **P. Chaipunya**, P. Kumam,**“On the proximal point method in Hadamard spaces,”**Optimization, Vol.66 (2017), Issue 10, pp.1647–1665.**P. Chaipunya**, P. Kumam,**“Recent fixed point techniques in fractional set-valued dynamical systems,”**in: Dynamical Systems – Analytical and Computational Techniques, M. Reyhanoglu (Ed.), 2017, InTech Publisher.- P. Saipara, W. Kumam,
**P. Chaipunya**,**“Modified random errors**Statistics, Optimization, and Information Computing, Vol.5 (2017), pp.65–74.*S*-iterative process for stochastic fixed point theorems in a generalized convex metric spaces,” **P. Chaipunya**, P. Kumam,**“On some classical soft intersection properties,”**The Journal of Nonlinear Science and Applications, Vol.9 (2016), pp.5136–5142.- A. Padcharoen, D. Gopal,
**P. Chaipunya**, P. Kumam,**“Fixed point and periodic point results for -type -contractions in modular metric spaces,”**Fixed Point Theory and Applications, 2016 (1), 39. **P. Chaipunya**, P. Kumam,**“On the solvability of generalized set-valued equilibrium problems,”**Journal of Nonlinear Analysis and Optimization, 2015 (In press).**P. Chaipunya**, P. Kumam,**“Fixed point theorems for cyclic operators with application in fractional integral inclusions with delays,”**Discrete and Continuous Dynamical Systems Supplement, Dynamical Systems, Differential Equations and Applications, AIMS Procedings, 2015, pp.248–257.- P. Saipara,
**P. Chaipunya**, Y.J. Cho, P. Kumam,**“On strong and -convergence of modified**The Journal of Nonlinear Science and Applications, Vol.8 (2015), pp.965–975.*S*-iteration for total asymptotically nonexpansive mappings in CAT() spaces,” **P. Chaipunya**, P. Kumam,**“Common fixed points for an uncountable family of weakly contractive operators,”**Carpathian Journal of Mathematics, Vol.31, No.3 (2015), pp.307–312.**P. Chaipunya**, P. Kumam,**“An observation on set-valued contraction mappings in modular metric spaces,”**Thai Journal of Mathematics, Vol.13, No.1 (2015), pp.9–17.**P. Chaipunya**, P. Kumam,**“Nonself KKM maps and corresponding theorems in Hadamard manifolds,”**Applied General Topology, Vol.16, No.1 (2015), pp.37–44.- K. Wongkum,
**P. Chaipunya**, P. Kumam,**“On the generalized Ulam-Hyers-Rassias stability of quadratic mappings in modular spaces without conditions,”**Journal of Function Spaces, Vol.2015, Article ID 461719, 2015. **P. Chaipunya**, Y.J. Cho, P. Kumam,**“A remark on the property and periodic points of order in cone metric spaces,”**Mathematiči Vesnik, 66, 4 (2014), pp.357–363.**P. Chaipunya**, Y.J. Cho, P. Kumam,**“On circular metric spaces and common fixed points for an infinite family of set-valued operators,”**Vietnam Journal of Mathematics, June 2014, Vol.42, Issue 2, pp.205–218.**P. Chaipunya**, P. Kumam,**“On the distance between three arbitrary points,”**Journal of Function Spaces and Applications, vol. 2013, Article ID 194631, 7 pages, 2013.**P. Chaipunya**, P. Kumam,**“Topological aspects of circular metric spaces and some observations on the KKM property towards quasi-equilibrium problems,”**Journal of Inequalities and Applications, 2013, 2013:343.- K. Wongkum,
**P. Chaipunya**, P. Kumam,**“Some analogies of the Banach contraction principle in fuzzy modular spaces,”**The Scientific World Journal, vol. 2013, Article ID 205275, 4 pages, 2013. **P. Chaipunya**, W. Sintunavarat, P. Kumam,**“On -contractions in ordered metric spaces,”**Fixed Point Theory and Applications, 2012, 2012:219.**P. Chaipunya**, Y.J. Cho, P. Kumam,**“Geraghty-type theorems in modular metric spaces with an application to partial differential equation,”**Advances in Difference Equations, 2012, 2012:83.**P. Chaipunya**, C. Mongkolkeha, W. Sintunavarat, P. Kumam,**“Fixed point theorems for multivalued mappings in modular metric spaces,”**Abstract and Applied Analysis, vol. 2012, Article ID 503504, 14 pages, 2012.