Atsushi Masumori

Dr. Atsushi Masumori

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Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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27 May 2025 in Frontiers in Robotics and AI
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Journal Article
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TYTakahide Yoshida
Takahide Yoshida
AMAtsushi Masumori
Atsushi Masumori
Takashi IkegamiTakashi Ikegami
Takashi Ikegami
This paper introduces Alter3, a humanoid robot that demonstrates spontaneous motion generation through the integration of GPT-4, a cutting-edge Large Language Model (LLM). This integration overcomes the challenge of applying LLMs to direct robot control, which typically struggles with the hardware-specific nuances of robotic operation. By translating linguistic descriptions of human actions into robotic movements via programming, Alter3 can autonomously perform a diverse range of actions, such as adopting a “selfie” pose or simulating a “ghost.” This approach not only shows Alter3’s few-shot learning capabilities but also its adaptability to verbal feedback for pose adjustments without manual fine-tuning. This research advances the field of humanoid robotics by bridging linguistic concepts with physical embodiment and opens new avenues for exploring spontaneity in humanoid robots.

13 December 2024 in Entropy
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RTRyosuke Takata
Ryosuke Takata
AMAtsushi Masumori
Atsushi Masumori
Takashi IkegamiTakashi Ikegami
Takashi Ikegami
We study the emergence of agency from scratch by using Large Language Model (LLM)-based agents. In previous studies of LLM-based agents, each agent’s characteristics, including personality and memory, have traditionally been predefined. We focused on how individuality, such as behavior, personality, and memory, can be differentiated from an undifferentiated state. The present LLM agents engage in cooperative communication within a group simulation, exchanging context-based messages in natural language. By analyzing this multi-agent simulation, we report valuable new insights into how social norms, cooperation, and personality traits can emerge spontaneously. This paper demonstrates that autonomously interacting LLM-powered agents generate hallucinations and hashtags to sustain communication, which, in turn, increases the diversity of words within their interactions. Each agent’s emotions shift through communication, and as they form communities, the personalities of the agents emerge and evolve accordingly. This computational modeling approach and its findings will provide a new method for analyzing collective artificial intelligence.

3 February 2017 in PLOS ONE
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LSLana Sinapayen
Lana Sinapayen
AMAtsushi Masumori
Atsushi Masumori
Takashi IkegamiTakashi Ikegami
Takashi Ikegami
Learning based on networks of real neurons, and learning based on biologically inspired models of neural networks, have yet to find general learning rules leading to widespread applications. In this paper, we argue for the existence of a principle allowing to steer the dynamics of a biologically inspired neural network. Using carefully timed external stimulation, the network can be driven towards a desired dynamical state. We term this principle “Learning by Stimulation Avoidance” (LSA). We demonstrate through simulation that the minimal sufficient conditions leading to LSA in artificial networks are also sufficient to reproduce learning results similar to those obtained in biological neurons by Shahaf and Marom, and in addition explains synaptic pruning. We examined the underlying mechanism by simulating a small network of 3 neurons, then scaled it up to a hundred neurons. We show that LSA has a higher explanatory power than existing hypotheses about the response of biological neural networks to external simulation, and can be used as a learning rule for an embodied application: learning of wall avoidance by a simulated robot. In other works, reinforcement learning with spiking networks can be obtained through global reward signals akin simulating the dopamine system; we believe that this is the first project demonstrating sensory-motor learning with random spiking networks through Hebbian learning relying on environmental conditions without a separate reward system.

18 January 2021 in Frontiers in Robotics and AI
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AMAtsushi Masumori
Atsushi Masumori
NMNorihiro Maruyama
Norihiro Maruyama
TITakashi Ikegami
Takashi Ikegami
In this study, we report the investigations conducted on the mimetic behavior of a new humanoid robot called Alter3. Alter3 autonomously imitates the motions of a person in front of it and stores the motion sequences in its memory. Alter3 also uses a self-simulator to simulate its own motions before executing them and generates a self-image. If the visual perception (of a person's motion being imitated) and the imitating self-image differ significantly, Alter3 retrieves a motion sequence closer to the target motion from its memory and executes it. We investigate how this mimetic behavior develops interacting with human, by analyzing memory dynamics and information flow between Alter3 and a interacting person. One important observation from this study is that when Alter3 fails to imitate a person's motion, the person tend to imitate Alter3 instead. This tendency is quantified by the alternation of the direction of information flow. This spontaneous role-switching behavior between a human and Alter3 is a way to initiate personality formation (i.e., personogenesis) in Alter3.

20 July 2015
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Conference Paper
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AMAtsushi Masumori
Atsushi Masumori
NMNorihiro Maruyama
Norihiro Maruyama
LSLana Sinapayen
Lana Sinapayen
TMTakeshi Mita
Takeshi Mita
UFUrs Frey
Urs Frey
TITakashi Ikegami
Takashi Ikegami
MIT Press Journals is a mission-driven, not-for-profit scholarly publisher devoted to the widest dissemination of its content.

1 September 2017
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Conference Paper
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IDItsuki Doi
Itsuki Doi
TITakashi Ikegami
Takashi Ikegami
AMAtsushi Masumori
Atsushi Masumori
HKHiroki Kojima
Hiroki Kojima
KOKohei Ogawa
Kohei Ogawa
HIHiroshi Ishiguro
Hiroshi Ishiguro