Hello! I'm Fergy. I have been a JSPS Postdoctoral Fellow since November 2024, mentored by Professor Masato Kimura, and was previously a Postdoctoral Researcher and a mentee of Professor Hirofumi Notsu at the Faculty of Mathematics and Physics, Kanazawa University. I also served as an Adjunct Assistant Professor at Temple University, Japan Campus from January to October 2024.

My current research interests include stationary free boundary and free surface problems, moving boundary problems, geometric inverse problems, and applications of shape optimization methods.

• PhD Informatics (2020), Nagoya University, Nagoya, Japan, 2017.10 – 2020.09

• MSc Mathematics (2017), University of the Philippines Baguio, Baguio City, Philippines, 2015.01 – 2017.01

• PMAM Actuarial Science (2015), University of the Philippines Diliman, Quezon City, Philippines, 2011.06 – 2015.01

• BSc Mathematics (2010), University of the Philippines Baguio, Baguio City, Philippines, 2007.06 – 2010.10

• Novel hybrid methods for accurate shape reconstruction: advancing theory and computational solutions
  Co-Investigator
  Grants-in-aid for JSPS Postdoctoral Fellows
  Japan Society for Promotion of Science
  KAKENHI Grant Number JP24KF0221
  JPY 2,400,000

• Development of effective and accurate non-conventional solution methods for shape inverse problems: theory and numerics
  Principal Investigator
  Grants-in-aid for Early-Career Scientists
  Japan Society for Promotion of Science
  KAKENHI Grant Number JP23K13012
  JPY 3,120,000

  (Discontinued as of October 31, 2024, due to the JSPS Postdoctoral Fellowship.)

23. E. Cherrat, L. Afraites, and J. F. T. Rabago
    Enhanced shape recovery in advection–diffusion problems via a novel ADMM-based CCBM optimization
    [PDF]    arXiv:2508.16898    doi:

24. M. Machida, H. Notsu, and J. F. T. Rabago
    A shape optimization approach for inverse diffusion problems using a single boundary measurement
    [PDF]    arXiv:2503.14764    doi:

1. J. F. T. Rabago and M. Kimura
   On the well-posedness of a Hele-Shaw-like system resulting from an inverse geometry problem formulated through a shape optimization setting
   ESAIM: Control, Optimisation and Calculus of Variations, Volume 31, 2025, Article Number 64, 65 pages
   [PDF]    arXiv:2407.03083    doi:10.1051/cocv/2025052

2. E. Cherrat, L. Afraites, and J. F. T. Rabago
   Numerical solution by shape optimization method to an inverse shape problem in multi-dimensional advection-diffusion problem with space dependent coefficients
   Applied Mathematics and Optimization, Volume 92, 2025, Article Number 13, 44 pages
   [PDF]    arXiv:2504.07796    doi:10.1007/s00245-025-10290-2

3. J. F. T. Rabago
   Localization of tumor through a non-conventional numerical shape optimization technique
   Applied Numerical Mathematics, Volume 217, November 2025, Pages 135-171.
   [PDF]    arXiv:2502.20656    doi:10.1016/j.apnum.2025.06.005

4. M. Essahraoui, E. Cherrat, L. Afraites, and J. F. T. Rabago
   Simultaneous recovery of a corroded boundary and admittance using the Kohn-Vogelius method
   in Computational Methods for Inverse Problems and Applications, ICMDS 2024, Khouribga, Morocco, October 21--22, 2024, Springer Proc. Math. Stat., vol. 498, Springer, Cham, 2025, Pages 73--89.
   [PDF]    arXiv:2506.17938    doi:10.1007/978-3-031-89498-5_6

5. J. F. T. Rabago, L. Afraites, and H. Notsu
   Detecting immersed obstacle in Stokes fluid flow using the coupled complex boundary method
   SIAM Journal on Control and Optimization, Volume 63, Issue 2, 2025, Pages 822-851
   arXiv:2403.11819    doi:10.1137/24M1647369

6. J. F. T. Rabago, A. Hadri, L. Afraites, A. S. Hendy, and M. A. Zaky
   A robust alternating direction method of multipliers numerical scheme for solving geometric inverse problems in a shape optimization setting
   Computers & Mathematics with Applications, Volume 175, September 2024, Pages 19-32
   arXiv:2301.10355v3    doi:10.1016/j.camwa.2024.08.034

7. L. Afraites and J. F. T. Rabago
   Boundary shape reconstruction with Robin condition: existence result, stability analysis, and inversion via multiple measurements
   Computational and Applied Mathematics, Volume 43, 2024, Article Number 270, 37 pages
   [PDF]    arXiv:2404.05202    doi:10.1007/s40314-024-02741-3

8. Y. Sunayama, M. Kimura, and J. F. T. Rabago
   Comoving mesh method for multi-dimensional moving boundary problems: mean-curvature flow and Stefan problems
   Mathematics and Computers in Simulation, Volume 221, July 2024, Pages 589-605
   [PDF]    doi:10.1016/j.matcom.2024.03.020

9. J. F. T. Rabago and H. Notsu
   Numerical solution to a free boundary problem for the Stokes equation using the coupled complex boundary method in shape optimization settings
   Applied Mathematics and Optimization, Volume 89, 2024, Article Number 2, 56 pages
   [PDF]    doi:10.1007/s00245-023-10065-7

10. E. Cherrat, L. Afraites, and J. F. T. Rabago
    Shape reconstruction for advection-diffusion problems by shape optimization method: the case of constant velocity
    Discrete and Continuous Dynamical Systems Series S, Volume 18, Issue 1, 2025, Pages 296-320
    [PDF]    doi:10.3934/dcdss.2023186

11. L. Afraites and J. F. T. Rabago
    Shape optimization methods for detecting an unknown boundary with the Robin condition by a single measurement
    Discrete and Continuous Dynamical Systems Series S, Volume 18, Issue 1, 2025, Pages 43-76
    [PDF]    doi:10.3934/dcdss.2022196

12. J. F. T. Rabago
    Numerical solution to the exterior Bernoulli problem using the Dirichlet-Robin energy gap cost functional approach in two and three dimensions
    Numerical Algorithms, Volume 94, February 2023, Pages 175-227
    [PDF]    doi:10.1007/s11075-023-01497-x

13. J. F. T. Rabago
    On the new coupled complex boundary method in shape optimization framework for solving stationary free boundary problems
    Mathematical of Control and Related Fields, Volume 13, Number 4, December 2023, Pages 1362-1398
    [PDF]    doi:10.3934/mcrf.2022041

14. Y. Sunayama, J. F. T. Rabago, and M. Kimura
    Comoving mesh method for certain classes of moving boundary problems
    Japan Journal of Industrial and Applied Mathematics, Volume 39, August 2022, Pages 973–1001
    [PDF]    doi:10.1007/s13160-022-00524-z

15. J. F. T. Rabago and H. Azegami
    A second-order shape optimization algorithm for solving the exterior Bernoulli free boundary problem using a new boundary cost functional
    Computational Optimization and Applications, Volume 77, June 2020, Pages 251-305
    [PDF]    doi:10.1007/s10589-020-00199-7

16. J. F. T. Rabago and H. Azegami
    A new energy-gap cost functional approach for the exterior Bernoulli free boundary problem
    Evolution Equations and Control Theory, Volume 8, Number 4, June 2019, Pages 785-824
    [PDF]    doi:10.3934/eect.2019038

17. J. F. T. Rabago and H. Azegami
    An improved shape optimization formulation of the Bernoulli problem by tracking the Neumann data
    Journal of Engineering Mathematics, Volume 117, Number 1, June 2019, Pages 1-29
    [PDF]    doi:10.1007/s10665-019-10005-x

18. J. F. T. Rabago and H. Azegami
    Shape optimization approach to defect-shape identification with convective boundary condition via partial boundary measurement
    Japan Journal of Industrial and Applied Mathematics, Volume 36, Number 1, June 2019, Pages 131-176
    [PDF]    doi:10.1007/s13160-018-0337-5

19. J. F. T. Rabago and J. B. Bacani
    Shape optimization approach for solving the Bernoulli problem by tracking the Neumann data: a Lagrangian formulation
    Communications in Pure & Applied Analysis, Volume 17, Number 6, June 2018, Pages 2683-2702
    [PDF]    doi:10.3934/cpaa.2018127

20. J. F. T. Rabago and J. B. Bacani
    Shape optimization approach to the Bernoulli problem: a Lagrangian formulation
    IAENG International Journal of Applied Mathematics, Volume 47, Number 4, November 2017, Pages 417-424
    [PDF]    doi:

21. J. B. Bacani and J. F. T. Rabago
    On the second-order shape derivative of the Kohn-Vogelius objective functional using the velocity method
    International Journal of Differential Equations, Volume 2015, December 2015, Article ID 954836, 10pp
    [PDF]    doi:10.1155/2015/954836

• Numerical methods for transport coefficient recovery
  2025 International Workshop on Modeling, Analysis and Computation with Application in Economics and AI & Joint Mathematics Symposium between Shanghai University of Finance and Economics and Kanazawa University
  Shanghai University of Finance and Economics, Shanghai, China, October 25–26, 2025

• Invited An inverse shape optimization approach for localizing tumors and burns
  11th International Conference on Inverse Problems, Control and Shape Optimization (PICOF'2025)
  Mehari Hammamet Hotel, Hammamet, Tunisia, October 28–31, 2025
  Talk scheduled on October 30, 2025.

• Invited Inverse geometry via shape optimization: numerical solution and well-posedness from a moving boundary framework
  Minisymposium on Recent Advances in PDE-constrained Optimizations (organized by W. Gong, S. Zhu, and Z. Zhou)
  The Third HKSIAM Biennial Conference
  The Chinese University of Hong Kong, Hong Kong, July 7–11, 2025
  Talk scheduled on July 8, 2025.

• Inverse geometric reconstruction of subdermal burn region from thermal data
  Minisymposium on Recent Advances in PDE-Constrained Optimization and Optimal Controls (organized by H. Fujiwara, W. Gong, and J. F. T. Rabago)
  The 18th SIAM East Asian Section Conference
  De La Salle University, Manila, Philippines, June 30–July 4, 2025
  Talk scheduled on July 2, 2025.

• Invited Shape optimization for inverse geometry: numerical methods and well-posedness in a moving boundary setting
  Shape Seminar
  東北大学 レジリエント社会構築イノベーションセンター 306 大会議室, June 23, 2025

• Invited Shape optimization for improved diagnosis: tumor localization and burn depth assessment
  Mathematical Society of the Philippines - CAR, Regions 1 and 2 Chapter: Mathematics Webinar Series
  online, May 24, 2025

• Localization of tumor through a non-conventional numerical shape optimization technique
  Workshop on Modeling and Numerical Analysis of Nonlinear Phenomena 2025
  Shiinoki Cultural Complex, Kanazawa, Japan, March 16–17, 2025
  Talk scheduled on March 16, 2025.

• Simultaneous reconstruction of shape and coefficients for corrosion detection via the Kohn-Vogelius approach
  第21回日本応用数理学会研究部会連合発表会
  岡山大学津島キャンパス、2025年3月5日〜3月7日
  Talk scheduled on March 5, 2025.

• Invited Obstacle detection in Stokes fluid flow using a novel shape optimization approach
  Russia-Japan-India Workshop "Mathematical analysis of fracture phenomena for elastic structures and its applications"
  via MS Teams, December 11–13, 2024
  Talk scheduled on December 12, 2024.

• Invited A Non-Conventional Reconstruction Approach for Parameter Identification in Inverse Optical Tomography with Single Boundary Measurement
  Inverse Days 2024
  Lapland Hotel Oulu, Oulu, Finland, December 10–13, 2024
  Talk scheduled on December 11, 2024.

• Invited Applications of Moving Meshes in Numerical Shape Optimization and Moving Boundary Problems
  RIMS joint research on the Development of Numerical Analysis that Contributes to Computational Science
  RIMS共同研究・計算科学に資する数値解析学の展開
  Kyoto University, Kyoto, Japan, October 23–25, 2024
  京都大学・数理解析研究所、2024年10月23日～25日
  Talk scheduled on October 23, 2024.

• Invited Non-conventional shape optimization techniques for shape identification problems
  Workshop for Young Scholars: Control and Inverse Problems on Waves, Oscillations and Flows - Mathematical Analysis and Computational Methods
  若手研究集会「波動・振動・流れの制御と逆問題 -理論と数値計算-」
  Kyoto University, Kyoto, Japan, September 24–25, 2024
  京都大学・理学研究科、2024年9月24日～25日
  Talk scheduled on September 25, 2024.

• Invited Numerical shape optimization method for parameter identification problems in diffuse optical tomography with a non-convex boundary interface using a single boundary measurement
  日本応用数理学会2024年度年会
  京都大学、2024年9月14日–16日
  Talk scheduled on September 14, 2024.

• A non-conventional shape optimization method for shape identification problems
  Minisymposium on Recent Advances in Numerical Shape Optimization Methods: From Theory to Practice (organized by W. Gong, S. Zhu, and J. F. T. Rabago)
  The 17th SIAM East Asian Section Conference
  University of Macau, Macao SAR, China, June 26–July 1, 2024

• Invited Obstacle detection in Stokes fluid flow using a novel shape optimization approach
  Minisymposium on Interface motion in complex systems (organized by M. Benes and K. Sakakibara)
  ALGORITMY 2024: Central-European Conference on Scientific Computing
  High Tatra Mountains, Slovakia, March 15–20, 2024

• Invited Non-conventional approximation procedures for parameter identification problems
  第20回日本応用数理学会研究部会連合発表会
  長岡技術科学大学、2024年3月4日〜3月6日

• On the application of Alternating Direction of Method of Multipliers to shape identification problems
  第20回日本応用数理学会研究部会連合発表会
  長岡技術科学大学、2024年3月4日〜3月6日

• On the coupled complex boundary method for obstacle shape recovery in Stokes fluid flow
  第25回研究集会数理設計研究部会
  香川大学町キャンパス、2023年12月19日

• Detecting immersed obstacle in Stokes fluid using coupled complex boundary method
  2023 Joint Meeting on Applied Mathematics, Organized by the Mathematical Society of Japan
  Faculty of Advanced Science and Technology, Ryukoku University, Seta Campus, Otsu, Shiga, Japan, December 14–16, 2023

• Invited Non-conventional shape optimization methods for solving shape inverse problems
  Minisymposium on Shape Optimization and Inverse Problems (organized by L. Afraites, A. Laurain, and J. F. T. Rabago)
  Applied Inverse Problems 2023
  University of Göttingen, Göttingen, Germany, September 4–8, 2023

• Invited Numerical solution to a free boundary problem for the Stokes equation using the coupled complex boundary method in shape optimization setting
  Minisymposium on Interface motion and related topics (organized by M. Beneš and T. Ishiwata)
  International Congress on Industrial and Applied Mathematics 2023
  Waseda University, Tokyo, Japan, August 20–25, 2023

• Part-Time Lecturer, Graduate Course: Applied Analysis
  Kanazawa University, Kanazawa City, Japan
  2025.04 - 2025.06, Q1
  2024.04 - 2024.06, Q1
  2023.04 - 2023.06, Q1

• Adjunct Assistant Professor, Undergraduate Courses: College Algebra
  Temple University, Japan Campus, Setagaya City, Japan
  2024.09 - 2024.10, Fall 2024
  2024.05 - 2024.08, Summer 2024
  2024.01 - 2024.04, Spring 2024

• Lecturer, Undergraduate Course: Pre-Calculus
  University of the Philippines Baguio, Baguio City, Philippines
  2015.01 - 2015.06

• Instructor, Undergraduate Courses: Mathematical Biology, Elementary Analysis, and Calculus
  Central Luzon State University, Science City of Muñoz, Nueva Ecija, Philippines
  2013.11 - 2014.04

• Lecturer, Undergraduate Courses: Elementary Analysis, Calculus, and Pre-Calculus
  Central Luzon State University, Science City of Muñoz, Nueva Ecija, Philippines
  2011.04 - 2013.10

• 研究集会等の情報 (Informations on Research Meetings, etc)

• 金沢解析セミナー (Kanazawa Analysis Seminar)

• 微分方程式とデータサイエンス研究会 (Differential Equations in Data Science)

• 現象数理解析研究会 (Workshop on Mathematical Analysis for Nonlinear Phenomena)

• Shape Seminar

• The 22nd Workshop on Mathematical Analysis for Nonlinear Phenomena

• International Conference: Differential Equations for Data Science 2025 (DEDS2025), Kyoto, Japan

• Workshop on Modeling and Numerical Analysis of Nonlinear Phenomena 2025 (MNANP2025), Kanazawa, Japan

• International Workshop on Computational and Mathematical Methods in Data Science 2025 (CoMaDS2025), Boracay, Aklan, Philippines

• The 18th SIAM East Asian Section Conference (EASIAM2025), Manila, Philippines

• SEAMS School 2025 Baguio (Inverse Problems and Optimal Control), Baguio, Philippines