Faculty Profiles - WAGATSUMA Hiroaki

Papers - WAGATSUMA Hiroaki

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Motor Imagery Classification Using Effective Channel Selection of Multichannel EEG Reviewed

Shiam A.A., Hassan K.M., Islam M.R., Almassri A.M.M., Wagatsuma H., Molla M.K.I.

Brain Sciences 14 ( 5 ) 2024.05

A Computational Approach for Global Trade Analysis Sensitive to Free Trade Agreement Circumstances: A Case Study Focusing on the Great Mekong Subregion Reviewed International journal

Altaweel Ahmad, Lee Bo-Young, Fujiwara Masayuki, Yoon Jang-Sok, Wagatsuma Hiroaki

Proceedings of International Conference on Artificial Life and Robotics ( ALife Robotics Corporation Ltd. ) 29 1042 - 1046 2024.02

Authorship：Last author Language：English Publishing type：Research paper (international conference proceedings)

In the Global Trade Analysis Project (GTAP), GDP and economic statistical indices can be analyzed for forecasting future trends in multiple countries by using the GTAP database and GEMPACK utilities, which realize the numerical calculation based on the concept of Computable General Equilibrium (CGE) models. Even with such well-prepared tools with the official database, appropriate forecasting is still difficult due to the sensitivity of the Free Trade Agreement (FTA) circumstances. FTA scenarios with a uniform tariff reduction can be assumed in general, while an abrupt and unreasonable change may occur in the simulation depending on the network structure of trading countries and the upper and lower bounds of tariffs in the time course. In the present study, we focused on the Great Mekong subregion (GMS) and explored possible methods to calculate substantially.

DOI： 10.5954/icarob.2024.gs6-2

CiNii Research

Trigger circuit design and system integration for simultaneous measurement of human EEG, motion, and gaze Reviewed International journal

Fujiwara M., Duc P.H.H., Bougrain L., Hénaff P., Wagatsuma H.

Proceedings of International Conference on Artificial Life and Robotics 1047 - 1050 2024.01

An Integration of Contact Force Models with Multibody Dynamics Analyses for Human Joint Mechanisms and Effects of Viscoelastic Ground Contact Reviewed International journal

Kasai S., Batbaatar D., Wagatsuma H.

Proceedings of International Conference on Artificial Life and Robotics 994 - 998 2024.01

An image processing mechanism for aerial inspection robots to detect submillimeter-width concrete cracks in social infrastructures Reviewed International journal

Dixit A., Oshiumi W., Shrivastava M., Wagatsuma H.

Advanced Robotics 38 ( 9-10 ) 698 - 714 2024.01

バイオメカトロニクスから生体レジリエンスへ Reviewed

我妻広明, 笠井慎太郎

情報・システムソサイエティ誌 ( 一般社団法人電子情報通信学会 ) 28 ( 3 ) 4 - 5 2023.11

Classification of Motor Imagery Using Trial Extension in Spatial Domain with Rhythmic Components of EEG Reviewed International journal

Molla M.K.I., Ahamed S., Almassri A.M.M., Wagatsuma H.

Mathematics 11 ( 17 ) 2023.09

Self-Growth Task Ontology Design Toward Realization of Artificial General Intelligence Invited

HIROAKI Wagatsuma

JSAI Technical Report, Type 2 SIG ( The Japanese Society for Artificial Intelligence ) 2023 ( AGI-023 ) 04 2023.03

Authorship：Lead author,　Last author,　Corresponding author Language：Japanese Publishing type：Research paper (conference, symposium, etc.)

<p>Artificial general intelligence (AGI) was defined as the ability of an intelligent agent to understand or learn intellectual tasks that human can do. As an actual goal to realize the agent, milestones or a fundamental principle is necessary to proceed in the engineering field. According to Marcus Hutter (2000), AGI was formulated as the agent maximizes "the ability to satisfy goals in a wide range of environments," which is assumed to be supported by a reinforcement learning scheme. However, there is a serious lack in the formulation, especially in the form of knowledge. Replacing of white-collar jobs by AI, an appropriate utilization of human expert knowledge depending on the current situation including context and common knowledge is crucial. Contextual knowledge utilization is a hard problem of AI as Hubert Dreyfus (1992) and Douglas Hofstadter (1979) noticed. In the present study, we have designed knowledge- based representation systems for assistance to workers in expert fields and verified its performance in the implementation to automated driving systems, failure diagnosis and programming-less planning in industrial robots for executing interactive missions with human workers. Our results contribute to the elucidation of the fundamental principle of AGI and then AGI will solve ill-posed problems in the real world in the near future.</p>

DOI： 10.11517/jsaisigtwo.2023.agi-023_04

CiNii Research

An Accuracy Evaluation of Multibody Dynamics for the Knee Support Exoskeleton Model with Respect to Implicit Methods for Numerical Integration Reviewed International journal

Kasai S., Wagatsuma H.

Proceedings of International Conference on Artificial Life and Robotics 989 - 993 2023.01

A Structure Pattern Extraction by Using Morphological Component Analysis in the Aerial Image Edge Detection Reviewed International journal

Oshiumi W., Dixit A., Wagatsuma H.

Proceedings of International Conference on Artificial Life and Robotics 883 - 887 2023.01

A Nonlinear Oscillator Coupling Model to Provide the Hough Transform Function Without the Discrete Voting Procedure Reviewed International journal

Purev Amarbold, Wagatsuma Hiroaki

Journal of Advances in Artificial Life Robotics ( ALife Robotics Corporation Ltd ) 3 ( 4 ) 185 - 192 2023.01

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

The most common algorithm for detecting straight lines in a digital image is the Hough Transform method. The method involves two consecutive steps: transforming the image edge location onto parameter space and voting procedure to acquire line characteristics. The former deals in continuous space, and the latter counts votes in a discrete matrix, making the algorithm sensitive to noise. We transformed each image pixel location to the parameter space as a Hough line and generated a nonlinear oscillator to attract them into the intersection with other lines. This concept could contribute to a line detection problem in image processing using a consistent mathematical description.

DOI： 10.57417/jaalr.3.4_185

CiNii Research

A Basic Concept of the Nonlinear Oscillator-Based Hough Transform Implementation to Improve the Voting Procedure in the Scheme of Continuous Dual Spaces Reviewed International journal

Purev A., Wagatsuma H.

Proceedings of International Conference on Artificial Life and Robotics 994 - 1003 2023.01

A Comparative Analysis of Numerical Integration in Explicit and Implicit Methods to be Evaluated in the Linkage Model with Multibody Dynamics Toward an Optimum Design of Support Devices for Human Joint Workload Reduction Reviewed International journal

Kasai Shintaro, Wagatsuma Hiroaki

Journal of Robotics, Networking and Artificial Life ( ALife Robotics Corporation Ltd. ) 10 ( 2 ) 198 - 203 2023.01

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

In the analysis based on multibody dynamics (MBD), the MBD models are described by ordinary
differential equations, and the numerical integration methods applied to the analysis nonnegligibly
affect the accuracy of the results. In consideration of models containing dynamic
components such as spring dampers and flexible elements, the selection of integration methods is
highly important not only for accuracy but also computational costs of the analysis, because it
easily causes integration errors. For the development of exoskeleton-type assistive devices using
flexible elements, an accurate assessment of the effect of their elastic properties is required. In the
present study, we applied the implicit integration method in order to improve the accuracy of
MBD-based analysis, and numerical errors in computer experiments were significantly reduced
in the case of implicit methods with respect to those caused by explicit methods. This verification
result can lead to the improvement of the accuracy of the inverse dynamics analysis based on the
flexible multibody dynamics (fMBD) theory.

DOI： 10.57417/jrnal.10.2_198

Scopus

CiNii Research

Other Link： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85194290245&origin=inward

A Comparative Analysis of Serial and Parallel Models in the Morphological Component Analysis-Based Structure Pattern Extraction for Aerial Image Edge Detections Reviewed International journal

我妻広明

Journal of Robotics, Networking and Artificial Life in press 2023.01

A Kamm’s Circle-Based Potential Risk Estimation Scheme in the Local Dynamic Map Computation Enhanced by Binary Decision Diagrams Reviewed International journal

Kumar A., Wagatsuma H.

Sensors 22 ( 19 ) 2022.10

A Linear-Time Algorithm to Form a Core Convex Shape from an Arbitrary Non-Convex for Automated Fulfillment in Robotic Manipulation Tasks Reviewed International journal

Altaweel, A., Uehara, K., Almassri, A. M. M., Wagatsuma, H.

International Journal of Engineering Advanced Research (IJEAR) 4 ( 3 ) 1 - 11 2022.09

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)

In the field of robotic manipulation, a fully automatic object fulfillment is an important issue in applications not only for high-density warehouse optimization but also for agricultural automation. In the present study, a formulation of the fulfillment of the maximum object into a given non-convex area was proposed. For minimizing redundant space inside a container during a packing task, the optimization problem is inevitable. Even edges of the target area are clearly detected, the best scenario to fill candidate objects sequentially is not apparently calculated. To deal with this problem, the proposed method is composed of two processes as decomposition of the original non-convex shape and reconstruction of a convex shape, based on theories of computational geometry. For example, it is difficult to judge a point either inside or outside of the area if it is non-convex, while it is easy to judge if the area is convex in the sense of the theorem of computational geometry. The proposed method is initiated by a recursive procedure proposed to decompose non-convex parts until it forms a remaining part to be a convex shape, and then it shifts to the reconstruction of a developing convex shape by adding decomposed parts in the first process, which it will be convex with the maximum size to be a subset of the original non-convex shape. It finally provides the right answer to be a filling area for candidate objects. Since the decomposition and reconstruction will be done in the circulation of removal and attachment of decomposed triangle parts, which takes computational costs of N (the number of nodes) steps as maximum in rotation as a linear- time algorithm. Theoretically, a simple detection algorithm of the maximum fulfillment area can be derived from an arbitrary combination of nodes as 2N. In the computer experiment, the reduction of the computational cost was clearly demonstrated in the comparison of the proposed method and the combinatory method. It contributes to the enhancement of the potential of computational geometry in an effective design of optimization units for robotics working in unstable and dynamic environments.

Determining the Elastic Properties of Flexible 3D Printed Beams with Variable Infill Densities and Patterns Reviewed International journal

Bhattacharjee, A., Dachkinov, P., Wagatsuma, H., Bhattacharya, B.

International Journal of Engineering Advanced Research (IJEAR) 4 ( 3 ) 12 - 24 2022.09

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)

Flexible non-linear 3D printed materials are rapidly gaining popularity in various engineering applications such as soft robotics, actuators, medical devices, etc. Due to their wide applicability, there is an increased research interest in characterization of their mechanical properties and performance. Unlike the conventional manufacturing processes, 3D printing has an additive character and allows for the geometry to be controlled from inside. The internal geometry and density corresponding to a given model can be tuned to a desired stiffness. In this study we investigate the effect of the infill percentage and infill geometry on the mechanical properties of 3D printed samples from flexible material by using a desktop type FDM 3D printer. The analyzed samples have the same shape and geometry – a beam with a square cross-section but the infill percentage is varied from 10 % to a 100 % with an increment of 15 %. The effects of three different types of infill geometries– rectangular, square and honeycomb have also been analytically determined. The approach for the analytical formulation adopts the methodology for calculating the in- plane properties and stiffnesses in cellular solids. The results for the mechanical properties for the different infill densities and infill geometries have been compared for all configurations. Despite the common external geometry of all beams, there is a significant change in their stiffness with the variation of the infill patterns and densities. Finally, a non-linear FEA study for the fully solid beam was conducted and compared with the analytical results. The method, used in this study can be applied for optimization of the stiffness to weight ratio during the design process of flexible 3D printed parts undergoing larger deformations.

A Comparative Study of Vector and Raster Spatial Data for Image Segmentation Focusing on the Position Estimation Accuracy of Vertices to Form Polygonal Shapes Reviewed International journal

Altaweel, A., Almassri, A. M. M., Purev, A., Wagatsuma, H.

International Journal of Engineering Advanced Research (IJEAR) 4 ( 3 ) 25 - 34 2022.09

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal)

In the field of image processing, raster data is frequently used for image segmentation and shape estimations for general purposes. On the other hand, in the medical field, which aims to help doctors in surgical operations, semi-automatic robotic manipulations such as the da Vinci Surgical Systemto minimize the necessary area to open for the living body. In the present study, a computational geometry-based method was proposed for vector data to treat the rearrangement of extracted points as candidates for edges of the target shape. On the other hand, the Harris-Stephens algorithm was introduced as a well-known method to detect vertices to form polygonal shapes in raster data as the counterpart in the comparative study. Typically, such a raster data method is not robust to perform in noisy conditions without appropriate filtering in the pre-processing. In the Harris-Stephens algorithm, the adding noises were detected as new vertices to form shapes in the area, which is inevitable in the condition without any semantic information about the shape. Since the proposed computational geometry-based method contains geometrical properties in its computation, it can be enhanced to be robust against noisy data. In the sense of designing a part of the system to be a surgical robot, which requires high accuracy of the position estimation of the target, a maximization of extractions of geometrical properties provides a significant benefit for accurate manipulation of robotic arms. It contributes not only to surgical robots but also to the solver of 2D replacement puzzles known as tangram puzzles to be a general scheme for robots in all fields behaving in dynamic environments.

Artificial Neural Network Approach to Guarantee the Positioning Accuracy of Moving Robots by Using the Integration of IMU/UWB with Motion Capture System Data Fusion Reviewed International journal

Almassri A.M.M., Shirasawa N., Purev A., Uehara K., Oshiumi W., Mishima S., Wagatsuma H.

Sensors 22 ( 15 ) 2022.08

A Computational Model of 3D Printing Orthoses Associated with a Systematic Structural Analysis toward Reverse Engineering Oriented Production Reviewed International journal

Dachkinov Pancho, Kasai Shintaro, Tanaka Kohei, Wagatsuma Hiroaki

ICIC Express Letters, Part B: Applications ( ICIC International ) 13 ( 7 ) 705 - 713 2022.07

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Papers - WAGATSUMA Hiroaki