A Scalable and robust quasi-newton framework for large-scale inverse analysis in nonlinear groundwater flow using initial guess modification

Inoue, Junya; Masumoto, Kiyoshi*

Advances in Water Resources, 212, 17 Pages, 2026/00

https://doi.org/10.1016/j.advwatres.2026.105280

Accurate inverse estimation of hydrogeological parameters in saturated-unsaturated flow models is essential for reliable groundwater simulations, particularly in large-scale three-dimensional domains. Quasi-Newton methods combined with adjoint-based gradients provide an efficient framework for high-dimensional inverse problems. However, in strongly nonlinear conditions, adaptive time-stepping strategies such as the Dynamic Time-Step Strategy (DTSS) introduce parameter-dependent time discretization, leading to iteration-dependent objective functions and violation of the secant condition in quasi-Newton updates. This degrades convergence performance. To address this issue, we propose the Initial Guess Modification Method (IGMM), which improves nonlinear robustness without modifying the time discretization. By maintaining a consistent time grid, IGMM preserves secant consistency and restores convergence. Numerical experiments, including a field-scale application at the Ningyo-Toge Mine, demonstrate stable convergence and accurate estimation of large parameter fields.

Soundness survey of cooling tower of Utility Cooling Loop (UCL Cooling Tower) in JMTR

Oto, Tsutomu; Asano, Norikazu; Kawamata, Takanori; Yanai, Tomohiro; Nishimura, Arashi; Araki, Daisuke; Otsuka, Kaoru; Takabe, Yugo; Otsuka, Noriaki; Kojima, Keidai; et al.

JAEA-Review 2020-018, 66 Pages, 2020/11

JAEA-Review-2020-018.pdf:8.87MB

A collapse event of the cooling tower of secondary cooling system in the JMTR (Japan Materials Testing Reactor) was caused by the strong wind of Typhoon No.15 on September 9, 2019. The cause of the collapse of the cooling tower was investigated and analyzed. As the result, it was identified that four causes occurred in combination. Thus, the soundness of the cooling tower of Utility Cooling Loop (UCL cooling tower), which is a wooden cooling tower installed at the same period as the cooling tower of secondary cooling system, was investigated. The items of soundness survey are to grasp the operation conditions of the UCL cooling tower, to confirm the degradation of structural materials, the inspection items and inspection status of the UCL cooling tower, and to investigate the past meteorological data. As the results of soundness survey of the UCL cooling tower, the improvement of inspection items of the UCL cooling tower was carried out and the replacement and repair of the structural materials of the UCL cooling tower were planned for safe maintenance and management of this facility. And the renewal plan of new cooling tower was created to replace the existing UCL cooling tower. This report is summarized the soundness survey of the UCL cooling tower.

Numerical experiments by saturated-unsaturated flow inversion for permeability and boundary conditions of multi-layers aquifer

Inoue, Junya; Masumoto, Kiyoshi*

Doboku Gakkai Rombunshu, A2 (Oyo Rikigaku) (Internet), 74(2), p.I_55 - I_64, 2019/01

https://doi.org/10.2208/jscejam.74.I_55

Saturated-unsaturated flow inversion program with adjoint method and least norm method was made to estimate saturated hydraulic conductivity and boundary conditions for multi-layers heterogeneous aquifer model. Vertical two dimensional numerical experiments assuming inclined ground consisting of three layers with different permeability were carried out using this program. Some inversion were carried out by changing the coefficient of least norm term to investigate the strength of constraints on the un-known parameters based on the reference value. The result show that it is possible to estimate the unique value of saturated hydraulic conductivity and boundary conditions for multi-layers heterogeneous aquifer model by the method.

Local deformation analysis in martensite layer of high-strength multilayered steel composite using synchrotron X-ray diffraction

Ojima, Mayumi*; Shiro, Ayumi*; Suzuki, Hiroshi; Inoue, Junya*; Shobu, Takahisa; Xu, P. G.; Akita, Koichi; Nambu, Shoichi*; Koseki, Toshihiko*

Zairyo, 66(6), p.420 - 426, 2017/06

https://doi.org/10.2472/jsms.66.420

Reactor dynamics experiment of nuclear ship Mutsu using pseudo random signal, (III); The third experiment

Hayashi, Koji; Shimazaki, Junya; Nabeshima, Kunihiko; Shinohara, Yoshikuni; Inoue, Kimio*;

JAERI-Research 95-015, 172 Pages, 1995/03

JAERI-Research-95-015.pdf:4.53MB

no abstracts in English

Reactor dynamics experiment of N.S.Mutsu using pseudo random signal, I; The First experiment

Hayashi, Koji; Shimazaki, Junya; Nabeshima, Kunihiko; Shinohara, Yoshikuni; Inoue, Kimio*;

JAERI-M 93-194, 163 Pages, 1993/10

JAERI-M-93-194.pdf:4.63MB

no abstracts in English

Evaluation of the internal strain in multilayered steel composite using white X-ray

Shiro, Ayumi; Shobu, Takahisa; Suzuki, Hiroshi; Ojima, Mayumi*; Nambu, Shoichi*; Inoue, Junya*

no journal, , 

no abstracts in English

High stereographic resolution texture and residual stress evaluation using time-of-flight neutron diffraction

Xu, P. G.; Harjo, S.; Ojima, Mayumi*; Ito, Takayoshi*; Gong, W.*; Suzuki, Hiroshi; Akita, Koichi; Inoue, Junya*; Tomota, Yo*; Aizawa, Kazuya

no journal, , 

Inverse analysis numerical experiment example of various unknown parameter setting in groundwater model

Masumoto, Kiyoshi*; Inoue, Junya

no journal, , 

no abstracts in English

Groundwater modeling for evaluation of radionuclide migration behavior

Inoue, Junya; Mori, Koji*; Murai, Nobuko*; Kanzaki, Norie

no journal, , 

no abstracts in English