Filters








1,683 Hits in 2.1 sec

Adversarial joint attacks on legged robots [article]

Takuto Otomo, Hiroshi Kera, Kazuhiko Kawamoto
2022 arXiv   pre-print
We address adversarial attacks on the actuators at the joints of legged robots trained by deep reinforcement learning. The vulnerability to the joint attacks can significantly impact the safety and robustness of legged robots. In this study, we demonstrate that the adversarial perturbations to the torque control signals of the actuators can significantly reduce the rewards and cause walking instability in robots. To find the adversarial torque perturbations, we develop black-box adversarial
more » ... cks, where, the adversary cannot access the neural networks trained by deep reinforcement learning. The black box attack can be applied to legged robots regardless of the architecture and algorithms of deep reinforcement learning. We employ three search methods for the black-box adversarial attacks: random search, differential evolution, and numerical gradient descent methods. In experiments with the quadruped robot Ant-v2 and the bipedal robot Humanoid-v2, in OpenAI Gym environments, we find that differential evolution can efficiently find the strongest torque perturbations among the three methods. In addition, we realize that the quadruped robot Ant-v2 is vulnerable to the adversarial perturbations, whereas the bipedal robot Humanoid-v2 is robust to the perturbations. Consequently, the joint attacks can be used for proactive diagnosis of robot walking instability.
arXiv:2205.10098v1 fatcat:rz6vbamveff5xhpnfwo3svpr2q

Adversarial Body Shape Search for Legged Robots [article]

Takaaki Azakami, Hiroshi Kera, Kazuhiko Kawamoto
2022 arXiv   pre-print
We propose an evolutionary computation method for an adversarial attack on the length and thickness of parts of legged robots by deep reinforcement learning. This attack changes the robot body shape and interferes with walking-we call the attacked body as adversarial body shape. The evolutionary computation method searches adversarial body shape by minimizing the expected cumulative reward earned through walking simulation. To evaluate the effectiveness of the proposed method, we perform
more » ... ents with three-legged robots, Walker2d, Ant-v2, and Humanoid-v2 in OpenAI Gym. The experimental results reveal that Walker2d and Ant-v2 are more vulnerable to the attack on the length than the thickness of the body parts, whereas Humanoid-v2 is vulnerable to the attack on both of the length and thickness. We further identify that the adversarial body shapes break left-right symmetry or shift the center of gravity of the legged robots. Finding adversarial body shape can be used to proactively diagnose the vulnerability of legged robot walking.
arXiv:2205.10187v1 fatcat:r4euymtbuzfozpbbcnsoa7wdiu

Immunoregulation in regenerative medicine

Hiroshi Kawamoto
2015 Inflammation and Regeneration  
iPSC stock project, autologous transplantation, allogeneic transplantation, immunogenicity Key words Special Issue (Brief Review) Immunoregulation in regenerative medicine Regenerative medicine field has been booming in recent years, and the invention of induce pluripotent stem cell (iPSC) technology has contributed a lot to this prosperity. One of the biggest advantageous points in the iPSC technology is that iPSCs can be produced from somatic cells of a patient and thus the regenerated cells
more » ... ay not be rejected after transplantation to the patient. Common people therefore seem to think that regenerative medicine is providing the technology to regenerate tissues/organs from their own cells. In medical terminology, this approach represents "autologous transplantation". However, in reality, regenerative medicine field is taking "allogeneic transplantation" strategy in the approaches using iPSCs, in which regenerated tissues are produced from iPSCs derived from other person. In such allogeneic transplantation, recipients can not be free from the problem that the transplanted tissues will be rejected by recipient's immune system. Hence it is important to conduct research of transplantation immunology in association with regenerative medicine. So called "iPSC stock project" is ongoing in Japan, in which iPSCs are established and stocked from HLA haplotype-homozygous (hereafter referred to as "homo") donors. Regenerated tissues can be transplanted to not only homo but also HLA haplotype-heterozygous (hereafter referred to as "hetero") recipients, since recipient T cells can not recognize the graft as non-self. It is said that 140 homo iPSC lines can cover 90 % of Japanese people. Then, are immunological issues solved by this homo-tohetero approach? The issues are not that simple. Actually, even in the HLA-fully matched transplantation, the grafts will be finally rejected due to the mismatch in minor histocompatibility antigens. It is probable that NK cells in hetero-recipients also can sense the absence of certain HLA molecules on the homo-graft and may exert immune reaction against grafts. Furthermore, iPSC-derived tissues could have unique immunogenicity, as discussed by R. Araki et al in this issue. Collectively, it would be inevitable that the recipients have to take immunosuppressive drugs for the rest of their life. If people get the fatal disease, it could be acceptable for them to take immunosuppressant to survive, but if it is not the fatal case, then the merit and
doi:10.2492/inflammregen.35.218 fatcat:efbqr2vusbg65fdj47hiz5im34

Treatment of Brain Abscess

Takashi KAWAMOTO, Hiroshi ABE, Hisatoshi SAITO, Kenichi KITAOKA
1987 Neurologia medico-chirurgica  
Thirty-eight cases of brain abscess observed from 1959 to 1983 were analyzed. Thirty-seven cases were operated on and 22 cases out of these were treated with aspiration, 14 cases with extra-capsular total excision, and one case with ventricular drainage. The operative mortality and morbidity were compared between the aspiration group and the excision group. Total surgical mortality rate was 14%. The surgical mortality rate of the aspiration group was 17% and that of the excision group was 7%.
more » ... vere consciousness disturbance was observed preoperatively in approximately 30% of the aspiration group. Surgical morbidity of the aspiration group was more favorable than that of the excision group. Postoperative convulsion was observed in 21% of the aspiration group and 15% of the excision group. Recurrence of abscess was observed in only one patient, who had malignant lymphoma. Brain abscess is considered to be cured by aspiration, appropriate chemotherapy and control of intracranial pressure. Extra-capsular total excision is unnecessary except in cases such as those resisting repeated aspiration.
doi:10.2176/nmc.27.429 pmid:2446182 fatcat:je3ave7ocjg6hm7tk7v3k2oyke

Macroscopic Quantum Tunneling in SQUID

Hiroshi Kawamoto
1987 Japanese Journal of Applied Physics  
Macroscopic Quantum Tunneling in SQUID To cite this article: Hiroshi Kawamoto 1987 Jpn. J. Appl. Phys. 26 1389 View the article online for updates and enhancements.  ... 
doi:10.7567/jjaps.26s3.1389 fatcat:o54vncgwbnanrosigltkuhjrke

Solvent Extraction of Cobalt (II) with HTTA and Pyridine

Hiroshi Kawamoto
1968 RADIOISOTOPES  
doi:10.3769/radioisotopes.17.8_388 fatcat:lz633qczcnczfgf5fau6rorgfy

Successful treatment of tabetic lightning pain and visceral crisis with gabapentin

Kyoko Oshita, Noboru Saeki, Hiroshi Niinai, Hiroshi Hamada, Masashi Kawamoto
2011 Journal of Anesthesia  
To the Editor: Lightning limb pain, a clinical feature of tabes dorsalis, is extremely severe and is refractory to various therapeutic approaches [1] . We report the case of a 61-year-old man who had severe paroxysmal lower limb pain for a decade because of tabes dorsalis. Nine years ago, he was diagnosed with tabes dorsalis and treated with high-dosage penicillin. The pain attacks were managed with carbamazepine. At the time of presentation, the patient complained of severe paroxysmal pain
more » ... was characterized by a pulling sensation extending from both legs up to the buttocks and which occurred three or four times daily. He writhed in pain, but apart from his pain attacks, he had no other complaints. Because an additional 200-mg dose of carbamazepine was ineffective, we added a 400-mg daily dose of gabapentin. The pain attacks disappeared on the second day after initiating this treatment regime. On the fifth day, he complained of sudden onset of left lower abdominal pain, i.e., a pulling sensation that extended upward from the anus and lasted for 2 h. A visceral crisis involving tabes dorsalis was suspected; therefore, we increased the gabapentin dosage to 600 mg daily, which reduced his abdominal pain the next day. On the 14th day, the patient experienced complete relief from pain with an 800-mg dose of gabapentin. Pain did not recur after carbamazepine was discontinued because of the toxic eruption on the 25th day. At the 1-year follow-up examination, he did not report recurring pain and complained only of slight dysesthesia in his right leg. The pathophysiology of tabes dorsalis involves leptomeningeal inflammation and atrophy of the posterior columns of the spinal cord and posterior nerve roots [1]. In most patients, pain often persists after antibiotic treatment [2, 3] and should be treated as neuropathic rather than inflammatory pain. Very few studies have been performed on tabetic pain treatment, and there are only several case reports on pain modulation by carbamazepine or sodium valproate [4, 5] . Our findings suggest that an alternative therapeutic regime involving gabapentin can effectively treat tabetic lightning pain. Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. References 1. Dourmishev LA, Dourmishev AL. Syphilis: uncommon presentations in adults. Clin Dermatol. 2005;23:555-64. 2. Giménez-Roldán S, Martín M. Tabetic lightning pains: highdosage intravenous penicillin versus carbamazepine therapy. Eur Neurol. 1981;20:424-8. 3. Mao S, Liu Z. Neurosyphilis manifesting as lightning pain. Eur J Dermatol. 2009;19:504-6. 4. Ekbom K. Carbamazepine in the treatment of tabetic lightning pains. Arch Neurol. 1972;26:374-8. 5. Bowsher D, Lahuerta J. A case of tabes dorsalis with tonic pupils and lightning pains relieved by sodium valporate.
doi:10.1007/s00540-011-1219-z pmid:21956795 pmcid:PMC3236825 fatcat:5k2sogesc5cqbhv6e665on7foy

Intrapersonal and interpersonal processes of social exclusion

Taishi Kawamoto, Mitsuhiro Ura, Hiroshi Nittono
2015 Frontiers in Neuroscience  
We have previously reported that activity in the dorsal anterior cingulate cortex (dACC) and right ventrolateral prefrontal cortex (rVLPFC) could be a neurocognitive index of social exclusion (Kawamoto  ...  et al., 2013a Kawamoto et al., , 2014 .  ...  et al., 2012 Kawamoto et al., , 2013b Moor et al., 2012; Themanson et al., 2013) .  ... 
doi:10.3389/fnins.2015.00062 pmid:25798081 pmcid:PMC4351632 fatcat:odlbyxbx7nafhi2wotphb6mr7e

Benign Osteoblastoma of the Atlas

Takashi KAWAMOTO, Kenichi KITAOKA, Hiroshi ABE, Nishio NAKAMURA
1985 Neurologia medico-chirurgica  
A benign osteoblastoma case of the atlas is reported. The patient, a 54-year-old male, was admitted because of nuchal pain. General examination revealed a tenderness of the posterior neck with paravertebral muscle spasms, but the neurological examination was not remarkable. Cervical spine radiography revealed an osteolytic and partially sclerotic lesion of the atlas with a thin bony shell. Bone scintigraphy showed a round high uptake. Computerized tomography scan disclosed a mixed density mass.
more » ... Myelography revealed smooth in dentation of the posterior subarachnoid space at C1-2 level. Angiography showed a faint tumor stain. The tumor was totally removed, and histological examination of the surgical specimen show ed the characteristic features of a benign osteoblastoma. The nuchal pain disappeared, and there has been no recurrence. Benign osteoblastoma is a rare benign bone tumor. It manifests a distinct predilection for the spine, and represents 3.7% of all tumors of the spine. Moreover, about a half of the benign osteo blastoma of the spine are accompanied with some neurological deficit.
doi:10.2176/nmc.25.223 pmid:2409469 fatcat:xln7quyaczgztktan5trbfvwti

Adversarial Bone Length Attack on Action Recognition [article]

Nariki Tanaka, Hiroshi Kera, Kazuhiko Kawamoto
2022 arXiv   pre-print
Supplementary material for Adversarial Bone Length Attack on Action Recognition Nariki Tanaka, Hiroshi Kera, Kazuhiko Kawamoto This supplementary material describes the preprocessing of the HDM05 dataset  ... 
arXiv:2109.05830v2 fatcat:xxl2gtjrnncqvep7cyrlnzcrna

Anti-Integrin Therapy for Multiple Sclerosis

Eiji Kawamoto, Susumu Nakahashi, Takayuki Okamoto, Hiroshi Imai, Motomu Shimaoka
2012 Autoimmune Diseases  
Kawamoto and S. Nakahashi) equally contributed to this paper E. Kawamoto, S. Nakahashi, T. Okamoto, H. Imai, and M. Shimaoka wrote this paper. H. Imai and M. Shimaoka supervised the project.  ... 
doi:10.1155/2012/357101 pmid:23346387 pmcid:PMC3533681 fatcat:inlgcrjq3jbe5ei6dnzprugvle

Single-valued wave function of the Aharonov-Bohm problem

Hiroshi Kawamoto
1994 Physics Letters A  
doi:10.1016/0375-9601(94)90357-3 fatcat:iyimhfh4evbeha2xuh442n2nsq

In Vitro Generation of Lymphohematopoietic Cells from Endothelial Cells Purified from Murine Embryos

Shin-Ichi Nishikawa, Satomi Nishikawa, Hiroshi Kawamoto, Hisahiro Yoshida, Masami Kizumoto, Hiroshi Kataoka, Yoshimoto Katsura
1998 Immunity  
doi:10.1016/s1074-7613(00)80581-6 pmid:9655490 fatcat:ug6y7vwylrfijkeic4hzhtateq

Synergistic extraction of dithizonatoferrate(II) with nitrogenous bases

Hideo AKAIWA, Hiroshi KAWAMOTO, Kuniji SUZUKI
1983 Bunseki Kagaku  
doi:10.2116/bunsekikagaku.32.4_e109 fatcat:3d4tawxld5c6zlui7uzggkllre

A Novel Flow Injection Technique: All Injection Analysis

Hideyuki ITABASHI, Hiroshi KAWAMOTO, Takuji KAWASHIMA
2001 Analytical Sciences  
All experiments were carried out at room temperature (ca. 293 KFlow Injection Technique: All Injection Analysis Hideyuki ITABASHI,* † Hiroshi KAWAMOTO,* and Takuji KAWASHIMA** *Department of Applied Chemistry  ... 
doi:10.2116/analsci.17.229 pmid:11993671 fatcat:udpttmftvvbv3dxoc2th2vpita
« Previous Showing results 1 — 15 out of 1,683 results