Jun Ota

Jun Ota
The University of Tokyo | Todai · Faculty & Graduate School of Engineering

About

600
Publications
45,200
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4,437
Citations

Publications

Publications (600)
Article
The Fugl-Meyer Assessment is widely used to test motor function in stroke survivors. In the Fugl-Meyer Assessment, stroke survivors perform several movement tasks and clinicians subjectively rate the performance of each task item. The individual task items in the Fugl-Meyer Assessment were selected based on clinical experience, and their physiologi...
Article
Automated guided vehicle (AGV) transportation systems are an important component of flexible warehouse systems, and research on the performance evaluation of AGV transportation systems contributes to the optimization and decision-making of flexible warehouse systems. Compared to simulation and experimental methods, analytic methods require less com...
Article
Full-text available
Although the overall number of fires is decreasing, the number of special fires as buildings become larger, taller, and deeper and fires and spills in hazardous materials facilities such as petroleum complexes is on the rise and ensuring the safety of firefighters has become a problem. The use of teleoperated firefighting robots is expected to be a...
Article
Full-text available
Research on mental health states involves paying increasing attention to changes in daily life. Researchers have attempted to understand such daily changes by relying on self-reporting through frequent assessment using devices (smartphones); however, they are mostly focused on a single aspect of mental health. Assessing the mental health of a perso...
Article
Full-text available
Humans are able to control their posture in their daily lives. It is important to understand how this is achieved in order to understand the mechanisms that lead to impaired postural control in various diseases. The descending tracts play an important role in controlling posture, particularly the reticulospinal and the vestibulospinal tracts (VST),...
Article
Full-text available
Post-stroke complications are the second most frequent cause of death and the third leading cause of disability worldwide. The motor function of post-stroke patients is often assessed by measuring the postural sway in the patients during quiet standing, based on sway measures, such as sway area and velocity, which are obtained from temporal variati...
Article
Conveyor systems involving multiple materials are commonly found in automated warehouse systems. The materials compete for the handling capability of the system and require complex operations where merging and splitting occur. It is difficult to analyze the handling capability competition between multiple materials and calculate the throughput of e...
Article
Full-text available
To more efficiently enhance the patient transfer skills of nursing students, this study aims to integrate a transfer skills evaluation system and a robot patient. The evaluation parameters, namely, the translational acceleration of the waist, rotational speed of the chest, and joint angles of the shoulder, hip, and knee, were selected on the basis...
Article
Background To maintain an upright standing posture against external disturbances, the human body mainly employs two types of postural control strategies: “ankle strategy” and “hip strategy.” While it has been reported that the magnitude of the disturbance alters the use of postural control strategies, it has not been elucidated how the level of mus...
Article
Parkinson's disease (PD) is a common neurological disorder, which causes instability in standing balance. The risk factors for falls in PD include disease severity, medication state (On/Off state), and dual tasking. The aim of this study was to assess the effects of dopaminergic medication and dual tasking on standing balance in PD by evaluating no...
Article
Estimation of continuous joint movement of human arm is significant in human-robot interaction. In this study, we proposed an estimating method combined continuous wavelet transform (CWT) and back propagation neural networks (BPNN) to estimate the joint angles and velocities of human arm from surface electromyography (sEMG) signals during the human...
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The development of body sensor networks (BSNs) with rich multimodal signals has enabled highly accurate fine-grained action detection, which is the cornerstone of many humancomputer interaction applications. However, in the case of consecutive fine-grained actions, most existing wearable sensor-based detection methods are constrained by sliding win...
Article
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Teleoperated robots are expected to perform tasks in unexpected disaster sites, which have become increasingly common in recent years. However, only few teleoperated robots are used for such purposes owing to their poor usability compared to the handling of such tasks by humans. Further, human-machine interfaces (HMI) used in teleoperated robots ar...
Article
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Recently, human patient simulators have been widely developed as substitutes for real patients with the objective of applying them as training tools in nursing education. Such simulated training is perceived as beneficial for imparting the required practical skills to students. Considering the aging world population, this study aimed to develop a r...
Article
Strokes are the third leading cause of disability worldwide. Currently, several types of performance assessment, such as the Fugl–Meyer index, are used to explore the overall difference between cerebral infarction (CI) and cerebral hemorrhage (CH) post-stroke patients. However, these performance assessments ignore subtle differences in the limbs of...
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Full-text available
This study addresses the challenging problem of efficient buffer allocation in production lines. Suitable locations for buffer allocation are determined to satisfy the desired throughput, while a suitable balance between solution quality and computation time is achieved. A throughput calculation approach that yields the state probability of product...
Article
Safety design of robot arm is important for human-robot interaction. In this paper, an anthropomorphic 7-DOF cable-driven manipulator including a 3-DOF shoulder joint module, a 1-DOF elbow joint module, and a 3-DOF wrist joint module is proposed for human-robot interaction. These three joint modules are connected serially and the motion transmissio...
Article
In the context of recent servitization of manufacturing characterized by IoT, Big data, and AI, we require a data-driven front-loading design of product with service. This paper proposes a design method of service system that encourages co-creation using a structural framework called TriCyPSS (Triple Cycles for Product Service System) from the view...
Article
Estimation of joint torque for human arm is important to help a robot adapt to a human partner in human-robot collaboration. In this study, we proposed an estimating model combined the back propagation neural networks (BPNN) and autoencoders to estimate the joint torque of human arm from surface electromyography (sEMG). Autoencoders were used to se...
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Full-text available
This paper proposes a system for tracking human position and head direction using fisheye camera mounted to the ceiling. This is believed to be the first system to estimate head direction from ceiling-mounted fisheye camera. Fisheye histograms of oriented gradients descriptor is developed as a substitute to the histograms of oriented gradients desc...
Article
Full-text available
Abstract Teleoperated robots are expected to perform tasks in extreme environments such as disaster sites. However, only few teleoperated robots are used for this purpose because their usability is poor compared to human skill in such tasks. Further, the use of human–machine interfaces used by teleoperated robots is in itself a human skill. In this...
Article
In this research, the automatic pipe routing system aimed at reducing the man-hours of piping design work is developed. In this system, the piping route is obtained by the Dijkstra method reflecting design knowledge obtained from hearing to the designers as evaluation values for getting a path that match the designer's intentions. By the verificati...
Conference Paper
In this paper we estimate the principal contact between an unknown manipulation-target object and its unknown environment, when the object is moved while keeping contact with the environment. We derived objective functions for two types of principal contacts, by focusing on the constraints caused by the contact. By minimizing the proposed objective...
Conference Paper
This paper presents the method for estimating three finger joints angle at the same time using four strings and three flexible layered belts. The method applied the difference of slide displacement of strings during finger flexion. The belt keeps the relative distance from the rotational center, and the relative displacement of strings is in propor...
Article
In this study, we propose a new algorithm to solve the rectangular strip packing problem (RSPP), a variant of the cutting stock problem in which the mother materials have a common fixed width and infinite length. Based on the column-generation technique with three improvements, the proposed algorithm can solve large-scale problems involving tens of...
Article
This research aimed to extract the design knowledge of piping in order to clarify the knowledge of piping design and to utilize it for designer education and automation. In order to extract design knowledge, we interviewed two expert designers, two middle-careered designers and one newcomer designer using protocol analysis method, and extracted a t...
Article
Full-text available
The order picking (OP) process includes several manual activities in which OP operators frequently load heavy items in awkward postures. Warehouse managers must manage operators’ health risks by determining an improvement strategy for the OP environment. This study proposes a technical method for segment picking activities and integrate them with p...
Article
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Taking a walk around in tourism destination areas has been attracting attention in recent years. However, supports for planning a tour incorporating a walk around was not sufficient at this moment. To serve this need, we develop a method to show tourists information on Point-of-Interests (POIs) for walking around major tourist attractions. Three ki...
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As information and communication technology systems become larger and more complex, system troubleshooting difficulty increases. To date, however, no efficient method for troubleshooting training has been developed owing to a lack of understanding of how skilled system engineers perform troubleshooting. The goal of this study was to investigate and...
Conference Paper
Full-text available
For supporting kaizen (continuous improvement) activities typically observed in Japanese manufacturing companies, we are developing the concept of ‘Digital Triple’ as an extension of Digital Twin. Digital Triplet contains intelligent activity world in addition to the cyber world and the physical world and emphasizes the ability of knowledge-based s...
Article
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In this paper, we developed an underactuated robotic finger with three joints having a branching tendon mechanism and a sensing system to estimate the wrench applied to the fingertip based on the moment-equivalent point (MEP). We proposed the design to combine the branching tendon mechanism and the principle of wrench sensing based on the MEP. The...
Article
A combination of fixed fisheye camera system and a blimp performed the task of human following in an indoor environment in this paper, focusing on tracking the subject's face. Hierarchical control algorithm is used to combine information from fisheye cameras and blimp's camera to track the face to handle common human's translation and rotation move...
Article
With the aim of enabling the aged to obtain timely nursing care and improve their quality of life, a novel method of motion planning for a six-degree-of-freedom (6-DoF) anthropomorphic robot arm to perform bandaging tasks is proposed. The motion planning of bandaging tasks is challenging because the collision avoidance problem and maintaining tensi...
Chapter
Full-text available
The Customer dysfunctional behaviors affect service providers’ workloads. However, few studies on service ecosystem design have investigated how to prevent these behaviors. This study thus proposes a service ecosystem design tool that can analyze how dysfunctional behaviors affect other actors in the service ecosystem. To this end, customers’ behav...
Chapter
Full-text available
This paper focuses on the cognitive competencies enabling front-line employees to grasp context, which previous has not taken into account. To this end, we developed two studies. Study 1 identifies the key factors and models the cognition during service based on interview data from flight attendants. Interview data was analyzed by Grounded Theory A...
Article
Full-text available
Muscle functional MRI (mfMRI) is an imaging technique that assess muscles’ activity, exploiting a shift in the T2-relaxation time between resting and active state on muscles. It is accompanied by the use of electromyography (EMG) to have a better understanding of the muscle electrophysiology; however, a technique merging MRI and EMG information has...
Chapter
It is necessary to consider operators’ health in order picking (OP). Automatic systems have been developed to offer posture risk feedback to operators but a lack of activity information limits the application of such systems in analyzing OP tasks and improving OP systems. Thus, this study develops an automatic risk evaluation system integrated with...
Article
Purpose The paper aims to propose an assembly scheme based on master–slave coordination for a compliant dual-arm robot to complete a peg-in-hole assembly task. Design/methodology/approach The proposed assembly scheme is inspired by the coordinated behaviors of human beings in the assembly process. The left arm and right arm of the robot are contro...
Article
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We present a highly accurate and efficient, yet simple, two-stage voting scheme for distinguishing inlier 3D correspondences by densely assessing and ranking their local and global geometric consistencies. The strength of the proposed method stems from both the novel idea of post-validated voting set, as well as single-point superimposition transfo...
Article
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Background: Humans use different postural control strategies depending on perturbations. The shift from an ankle strategy to a hip strategy occurs at different perturbation magnitudes for different individuals. Although such differences relate to the differences in body parameters such as muscle strength, the parameter changes that affect the stra...
Article
Robotics is becoming increasingly important in modern engineering areas. After the big nuclear accidents in Fukushima 2011, the crossing research of nuclear and robotics draws more and more attentions. In this paper, a method for radioactive source recognition using moving Compton camera imaging robot is proposed. In order to assess the quality of...
Conference Paper
Recognizing human cognitive performance is important for preserving working efficiency and preventing human error. This paper presents a method for estimating cognitive performance by leveraging multiple information available in a smartphone. The method employs the Go-NoGo task to measure cognitive performance, and fuses contextual and behavioral f...
Article
Full-text available
Analyzing throughput is very important for the design, optimization, and management of production lines. In this paper, we present an efficient throughput analysis approach for production lines with merging, splitting, and recirculating topologies. In particular, we define a decomposition regulation based on queue modules for the decomposition of t...
Conference Paper
In the last years the spread of hand prosthetics has fueled the research on the field of signal processing applied on physiologic data. At the state of the art there are different algorithms that allow a precise estimation of hand movements, the majority of whom work just on the electrode space. Even though there are signal processing methods that...
Conference Paper
In this research, we aimed to estimate the contact condition between an object and the environment using the information on motion, when a person manipulates an object while making contact with the environment. The shape of the object was assumed to be unknown. We classified the contact conditions according to the restriction of their motion and pr...
Article
This paper proposes a method to generate a 2.5D map for an indoor environment with floors including non-horizontal partial areas by plotting the range data measured by a wheeled robot having two 2D range finders and a 3D gyroscope. For precise map generation, this method estimates the robot's 3D orientation by using not only the gyroscope but also...
Conference Paper
In the recent years important steps forward have been made in the field of signal processing on muscle signals for hand prosthetics control. At the state of the art different algorithms and techniques allow a precise estimation of hand movements. However, they mostly work exclusively on the electrode space, not seeking for any information about the...
Article
Full-text available
As observed in musical ensembles, people synchronize with a leader together with other people. This study aimed to investigate whether interdependency with a partner improves performance accuracy in rhythm synchronization with the leader. Participants performed a synchronization task via auditory signal by finger tapping in which two followers simu...
Article
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In this paper, we propose an optimization method to determine the design parameters comprising joint displacement parameters in a serial manipulator having small degrees of freedom realizing an approximated target trajectory. Using generalized differential kinematics, we can achieve efficient optimization without solving the inner-loop optimization...
Article
In Shop Scheduling problems, minimising total processing time (makespan) by means of heuristic methods is one of the main goals for throughput optimisation. Furthermore, reliably estimating makespan is critical for new order acceptance and for heuristic method selection. However, heuristic methods solutions either come without estimates or with ver...
Article
Full-text available
The human body is a complex system driven by hundreds of muscles, and its control mechanisms are not sufficiently understood. To understand the mechanisms of human postural control, neural controller models have been proposed by different research groups, including our feed-forward and feedback control model. However, these models have been evaluat...
Data
Perturbed stance simulation video. (MP4)
Data
Selected uff. A total of 70 types of muscle activations used as uff are indicated. (CSV)
Data
Optimized PD gains. P and D gains for 11 muscle groups are indicated. For example, p_lumbar_extension is the P gain for the lumber extension muscle group, and d_lumbar_extension is the D gain for the lumbar extension muscle group. Because the musculoskeletal model is symmetrical, the directions of 120°–240°are omitted (e.g., left-sided muscle activ...
Data
Initial posture. The information of the initial pose of pelvis (pelvis_tilt, pelvis_list, pelvis_rotation, pelvis_tx, pelvis_ty, and pelvis_tz) and initial joint angles (hip_flexion_r (q2), hip_adduction_r (q12), hip_rotation_r (q9), knee_angle_r (q3), ankle_angle_r (q4), subtalar_angle_r (q14), hip_flexion_l (q5), hip_adduction_l (q13), hip_rotati...
Article
This study predicts the change of stress levels using real-world and online behavioral features extracted from smartphone log information. Previous studies of stress detection using smartphone data focused on a single feature and did not consider all features simultaneously. We propose a method to extract a co-occurring combination of a user's real...
Article
With the number of hospital stays increasing, nurses require more training to handle a variety of patients. However, time for training in nursing schools is limited, and students lack the opportunity to practice on a diverse variety of patients. Using a robot to simulate actual patients, this study observes the learning transfer effect of practice...
Article
Full-text available
If we define a mode as a set of specific configurations that hold the same constraint, and if we investigate their transitions beforehand, we can efficiently probe the configuration space by using a manipulation planner. However, when multiple mobile robots together manipulate an object by using the non-prehensile method, the candidates for the mod...
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Local image features are invariant to in-plane rotations and robust to minor viewpoint changes. However, the current detectors and descriptors for local image features fail to accommodate out-of-plane rotations larger than 25°–30°. Invariance to such viewpoint changes is essential for numerous applications, including wide baseline matching, 6D pose...