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How Does AI Think? KAIST Achieves First Visualization of the Internal Structure Behind AI Decision-Making
<(From Left) Ph.D candidate Daehee Kwon, Ph.D candidate Sehyun lee, Professor Jaesik Choi>
Although deep learning–based image recognition technology is rapidly advancing, it still remains difficult to clearly explain the criteria AI uses internally to observe and judge images. In particular, technologies that analyze how large-scale models combine various concepts (e.g., cat ears, car wheels) to reach a conclusion have long been recognized as a major unsolved challenge.
KAIST (President Kwang Hyung Lee) announced on the 26th of November that Professor Jaesik Choi’s research team at the Kim Jaechul Graduate School of AI has developed a new explainable AI (XAI) technology that visualizes the concept-formation process inside a model at the level of circuits, enabling humans to understand the basis on which AI makes decisions.
The study is evaluated as a significant step forward that allows researchers to structurally examine “how AI thinks.”
Inside deep learning models, there exist basic computational units called neurons, which function similarly to those in the human brain. Neurons detect small features within an image—such as the shape of an ear, a specific color, or an outline—and compute a value (signal) that is transmitted to the next layer.
In contrast, a circuit refers to a structure in which multiple neurons are connected to jointly recognize a single meaning (concept). For example, to recognize the concept of cat ear, neurons detecting outline shapes, neurons detecting triangular forms, and neurons detecting fur-color patterns must activate in sequence, forming a functional unit (circuit).
Up until now, most explanation techniques have taken a neuron-centric approach based on the idea that “a specific neuron detects a specific concept.” However, in reality, deep learning models form concepts through cooperative circuit structures involving many neurons. Based on this observation, the KAIST research team proposed a technique that expands the unit of concept representation from “neuron → circuit.”
The research team’s newly developed technology, Granular Concept Circuits (GCC), is a novel method that analyzes and visualizes how an image-classification model internally forms concepts at the circuit level.
GCC automatically traces circuits by computing Neuron Sensitivity and Semantic Flow. Neuron Sensitivity indicates how strongly a neuron responds to a particular feature, while Semantic Flow measures how strongly that feature is passed on to the next concept. Using these metrics, the system can visualize, step-by-step, how basic features such as color and texture are assembled into higher-level concepts.
The team conducted experiments in which specific circuits were temporarily disabled (ablation). As a result, when the circuit responsible for a concept was deactivated, the AI’s predictions actually changed.
In other words, the experiment directly demonstrated that the corresponding circuit indeed performs the function of recognizing that concept.
This study is regarded as the first to reveal, at a fine-grained circuit level, the actual structural process by which concepts are formed inside complex deep learning models. Through this, the research suggests practical applicability across the entire explainable AI (XAI) domain—including strengthening transparency in AI decision-making, analyzing the causes of misclassification, detecting bias, improving model debugging and architecture, and enhancing safety and accountability.
The research team stated, “This technology shows the concept structures that AI forms internally in a way that humans can understand,” adding that “this study provides a scientific starting point for researching how AI thinks.”
Professor Jaesik Choi emphasized, “Unlike previous approaches that simplified complex models for explanation, this is the first approach to precisely interpret the model’s interior at the level of fine-grained circuits,” and added, “We demonstrated that the concepts learned by AI can be automatically traced and visualized.”
< Overview of the Conceptual Circuit Proposed by the Research Team >
This study, with Ph.D. candidates Dahee Kwon and Sehyun Lee from KAIST Kim Jaechul Graduate School of AI as co–first authors, was presented on October 21 at the International Conference on Computer Vision (ICCV).
Paper title: Granular Concept Circuits: Toward a Fine-Grained Circuit Discovery for Concept Representations
Paper link: https://openaccess.thecvf.com/content/ICCV2025/papers/Kwon_Granular_Concept_Circuits_Toward_a_Fine-Grained_Circuit_Discovery_for_Concept_ICCV_2025_paper.pdf
This research was supported by the Ministry of Science and ICT and the Institute for Information & Communications Technology Planning & Evaluation (IITP) under the “Development of Artificial Intelligence Technology for Personalized Plug-and-Play Explanation and Verification of Explanation” project, the AI Research Hub Project, and the KAIST AI Graduate School Program, and was carried out with support from the Defense Acquisition Program Administration (DAPA) and the Agency for Defense Development (ADD) at the KAIST Center for Applied Research in Artificial Intelligence.
2025.11.26 View 1020 -
KAIST K HERO Rides Nuri Rocket, Next Generation Micro Hall Thruster Technology Verified in Space
< (From left) Ph.D candidate Jaehong Park, COSMOVY researcher Yoonsoo Kim, Professor Wonho Choe, Ph.D candidate Dongha Park, M.S candidate Seungbeom Heo >
KAIST announced on the November 26th that the CubeSat 'K-HERO (KAIST Hall Effect Rocket Orbiter)', developed by the research team of Professor Wonho Choe from the Department of Nuclear and Quantum Engineering, is scheduled to launch into space aboard the 4th Nuri rocket launch vehicle on November 27th from the Naro Space Center in Goheung, Jeollanam-do.
This 4th Nuri launch is the first to be managed by the private company Hanwha Aerospace, which received technology transfer from the Korea Aerospace Research Institute (KARI), marking a significant milestone in the transformation of the domestic space industry. Along with the main payload, the Next-Generation Medium Satellite 3, twelve CubeSats developed by industry, academia, and research institutions will be onboard, with K-HERO being one of them.
The development of K-HERO was officially initiated when Professor Wonho Choe's research team was selected as the basic satellite development team in the '2022 CubeSat Competition' organized by KARI.
The basic satellite is a technology verification satellite designed to confirm whether the design and core components operate normally in the space environment before proceeding with the flight model (FM) production. K-HERO is a 3U standard CubeSat with dimensions of $10\text{ cm}$ (width) $\times$ $10\text{ cm}$ (length) $\times$ $30\text{ cm}$ (height) and a weight of $3.9\text{ kg}$. It was designed to satisfy all stability, electrical specifications, and interface conditions with the launch vehicle.
The core mission of K-HERO is to directly verify the in-space operation of the 150 W class micro-satellite Hall thruster developed by the research team.
The Hall thruster can be simply described as a 'space engine powered by electricity'. It is an electric propulsion engine that moves the satellite slowly but very efficiently using electricity.
Instead of burning a lot of fuel to generate instantaneous thrust, like a rocket, it works by using electricity to turn gas (Xenon) into a plasma state and rapidly accelerating it backward to push the satellite forward. Hall thrusters are considered a core technology for the era of small and constellation satellites due to their high fuel efficiency.
< Image of plasma generation in the micro-satellite Hall thruster mounted on the K-HERO CubeSat >
Hall thrusters are already a proven technology, having been used in large satellites and deep-space probes for over 20-30 years. However, their size and power requirements were large, so in the past, they were mainly operated on large geostationary (GEO) communication/broadcasting satellites and used by NASA and ESA deep-space probes for long-distance flights.
Recently, the emergence of the SpaceX Starlink satellite constellation has led to a surge in demand for small and micro electric thrusters. As the global space industry shifts towards satellite constellations, 'small and efficient thrusters' have become essential technology.
K-HERO is the first case of direct in-space demonstration of a micro Hall thruster made with domestic technology, and it is expected to be an important milestone in enhancing domestic technological competitiveness.
Professor Wonho Choe's research team began research on Hall thrusters in Korea in 2003, securing original technology based on plasma physics. In 2013, they successfully mounted a 200 W class Hall thruster on the 'KAIST Science and Technology Satellite 3,' proving its practical utility. This time, they have improved the design to operate even at a lower power of 30 W, developing a next-generation model aimed at micro-satellites.
COSMOVY Inc, a laboratory startup founded by Professor Wonho Choe's research team, also participated in the development of K-HERO, further strengthening the foundation for technology commercialization.
< K-HERO CubeSat being loaded into the Nuri rocket's CubeSat dispenser (Photo source: Korea Aerospace Research Institute) >
Professor Wonho Choe stated, "Starting with K-HERO, the number of small satellites equipped with electric thrusters will increase significantly in Korea. The Hall thruster being verified this time can be utilized for various missions, including low-Earth orbit constellation surveillance and reconnaissance satellites, 6G communication satellites, very-low-Earth orbit high-resolution satellites, and asteroid probes."
President Kwang Hyung Lee stated, "The launch of K-HERO is a significant opportunity to directly verify KAIST's electric propulsion technology on a micro-satellite platform once again in space, and it will be an important turning point that will further enhance the technological competitiveness of small satellites in Korea. KAIST will continue to contribute to the development of our country's space technology.
2025.11.26 View 444 -
KAIST Confirms Reduction of Amyloid-β Using Red OLED-Restores Memory in Alzheimer’s Model
<Professor Kyung Cheol Choi, Dr. Byeongju Noh, Ph.D candidate Young-Hun Jung, Ph.D candidate Minwoo Park, Dr.Ja Wook Koo, Researcher Jiyun Lee, Researcher Ji-Eun Lee, Dr. Hyang Sook Hoe, Dr. Hyun-Ju Lee, Dr. Sora Kang, Researcher Seokjun Oh>
A Korean research team, raising the question “Which OLED light color can actually improve memory and pathological markers in Alzheimer’s patients?”, has identified the most effective OLED color capable of enhancing cognitive function using only light—with no drugs involved. The OLED platform developed for this study can precisely control color, brightness, flicker frequency, and exposure duration, suggesting potential future development into personalized OLED-based electroceuticals.
On the 24th, KAIST (President Kwang Hyung Lee) announced that a joint research team led by Professor Kyung Cheol Choi from the School of Electrical Engineering at KAIST and Dr. Ja Wook Koo and Dr. Hyang Sook Hoe from the Korea Brain Research Institute (KBRI) developed a uniform-illuminance, three-color OLED photostimulation technology and confirmed that “red 40-Hz light” was the most effective among blue, green, and red in improving Alzheimer's pathology and memory function.
To overcome the structural limitations of conventional LEDs—such as brightness imbalance, heat generation risk, and variability caused by animal movement—the researchers developed an OLED-based photostimulation platform that emits light uniformly. Using this platform, they compared white, red, green, and blue light under identical conditions (40-Hz frequency, brightness, and exposure time) and found that red 40-Hz light produced the most significant improvement.
In an early-stage (3-month-old) Alzheimer’s animal model, improvement in pathology and memory was observed after only two days of stimulation. When early Alzheimer’s model mice were exposed to one hour of light per day for two days, both white and red light improved long-term memory. Additionally, the amount of amyloid-β (Aβ) plaques—protein aggregates known as a major factor in Alzheimer’s disease—was reduced in key brain regions such as the hippocampus, and levels of the plaque-clearing enzyme ADAM17 increased.
This indicates that even very short periods of light stimulation can reduce harmful proteins in the brain and improve memory function. In particular, with red light, the inflammatory cytokine IL-1β, known to exacerbate inflammation and contribute to Alzheimer’s progression, decreased significantly, demonstrating an anti-inflammatory effect.
Moreover, the more plaque was reduced, the greater the improvement in memory—direct evidence that pathological improvement leads to cognitive enhancement.
In the mid-stage (6-month-old) Alzheimer’s model, statistically significant pathological improvement was seen only with red light. In a two-week long-term stimulation experiment under the same conditions, both white and red light improved memory, but a statistically meaningful reduction in plaques appeared only under red light.
< The mechanism by which red OLED stimulation of neurons reduces amyloid-β in Alzheimer’s model mice >
Differences at the molecular level were also clear. Under red light, levels of ADAM17 (which helps remove plaques) increased, while levels of BACE1, an enzyme responsible for producing plaques, decreased—demonstrating a dual effect of both inhibiting plaque formation and promoting plaque removal. In contrast, white light only lowered BACE1, showing more limited therapeutic effects compared to red light.
This scientifically identifies that the color of light is a key factor determining therapeutic efficacy.
To determine which neural circuits were activated by light stimulation, the team analyzed the expression of c-Fos, an immediate-early gene that is activated when neurons fire.
They found activation throughout the visual–memory circuit, extending from the visual cortex → thalamus → hippocampus, providing direct neurological evidence that light stimulation awakens the visual pathway, enhancing hippocampal function and memory.
Thanks to the uniform-illuminance OLED platform, light was evenly delivered regardless of animal movement, ensuring stable experimental results and high reproducibility across repeated tests.
This study is the first to demonstrate that cognitive function can be improved using only light, without drugs, and that Alzheimer’s pathological markers can be regulated through combinations of light color, frequency, and duration.
The OLED platform developed in this study allows fine control over color, brightness, flicker ratio, and exposure time, making it suitable for personalized stimulation design in future human clinical research.
The research team plans to expand conditions such as stimulation intensity, energy, duration, and combined visual–auditory stimulation, aiming toward clinical-stage development.
Dr. Byeongju Noh (from Professor Kyung Cheol Choi’s research team) said, “This study experimentally demonstrates the importance of color standardization and confirms that red OLED is the key color that activates ADAM17 and suppresses BACE1 across disease stages.”
Professor Kyung Cheol Choi emphasized, “Our uniform-illuminance OLED platform overcomes the structural limitations of traditional LEDs and enables high reproducibility and safe evaluation. We expect wearable RED OLED electroceuticals for everyday use to present a new therapeutic paradigm for Alzheimer’s disease.”
The research findings were published online on October 25 in ACS Biomaterials Science & Engineering, a leading international journal in biomedical and materials science.
Paper Title: Color Dependence of OLED Phototherapy for Cognitive Function and Beta-Amyloid Reduction through ADAM17 and BACE1
DOI: https://pubs.acs.org/doi/full/10.1021/acsbiomaterials.5c01162
Co-authors:Byeongju Noh, Hyun-Ju Lee, Jiyun Lee, Jiyun Lee, Ji-Eun Lee, Bitna Joo, Young-Hun Jung, Minwoo Park, Sora Kang, Seokjun Oh, Jeong-Woo Hwang, Dae-Si Kang, Yongmin Jeon, So-Min Lee, Hyang Sook Hoe, Ja Wook Koo, Kyung Cheol Choi
This research was supported by the National Research Foundation of Korea and the National IT Industry Promotion Agency under the Ministry of Science and ICT, and the Korea Brain Research Institute Basic Research Program. (2017R1A5A1014708, 2022M3E5E9018226, H0501-25-1001, 25-BR-02-02, 25-BR-02-04)
2025.11.24 View 601 -
KAIST Professor and Alumni Who Won AIxCC Donate 150 Million KRW of Prize Money to Their Alma Mater
<(From Left) Professor Insu Yun from KAIST School of Electrical Engineering, Researcher HyungSeok Han from Samsung Research America>
KAIST (President Kwang Hyung Lee) announced on the 23rd of November that HyungSeok Han (Ph.D. alumnus from the School of Computing) and Insu Yun (B.S. alumnus, currently Associate Professor in the School of Electrical Engineering) donated 150 million KRW from the prize money won by Team Atlanta, which took first place in the world’s largest AI security competition, the “AI Cyber Challenge (AIxCC),” organized by the U.S. Defense Advanced Research Projects Agency (DARPA).
The AIxCC final round was held this August in Las Vegas, where Team Atlanta—a joint team consisting of researchers from Samsung Research, KAIST, POSTECH, and Georgia Tech—secured the top prize. AIxCC is the world’s largest AI security competition, with a total prize pool of 29.5 million USD (approx. 41 billion KRW). Over the past two years, security companies and research teams worldwide have competed with AI-based security technologies, showcasing state-of-the-art capabilities.
A total of 91 teams registered for the competition, 31 teams participated in the qualifiers, and 7 teams advanced to the finals. Team Atlanta won the first-place prize of 4 million USD (approx. 5.8 billion KRW), securing victory with an overwhelming margin comparable to the combined scores of the second- and third-place teams. The team also swept major titles such as “Most Vulnerabilities Identified” and “Highest Scoring Team,” demonstrating exceptional technical superiority.
HyungSeok Han earned his B.S. (2017) and Ph.D. (2023) from the KAIST School of Computing, then worked as a postdoctoral researcher at Georgia Tech before joining Samsung Research America where he currently works. In the competition, he served as the team leader for the development of the automatic vulnerability detection system and oversaw system integration and infrastructure, making major contributions.
Insu Yun received his B.S. (2015) from the KAIST School of Computing and his Ph.D. (2020) from Georgia Tech. Since 2021, he has been a faculty member in the KAIST School of Electrical Engineering. In this competition, he led the patch development team and played a central role in enhancing overall system completeness.
The two researchers decided to donate 150 million KRW of their prize money to the School of Computing and the School of Electrical Engineering. The School of Computing will use the donation as a scholarship fund, while the School of Electrical Engineering will apply it toward student education and research support, in line with the spirit of the donation.
Alumnus HyungSeok Han remarked, “Building a system in which AI autonomously discovers vulnerabilities and even generates patches has long been a dream of mine and an important milestone in the security field. I’m grateful to have achieved meaningful results together with KAIST alumni, and I hope KAIST will continue to exert a positive influence on global technological advancement.”
<Final Scoreboard>
Professor Insu Yun stated, “I’m truly grateful to every member of Team Atlanta. In particular, I want to thank Professor Taesoo Kim, our overall team leader and advisor, the students in our lab who worked tirelessly, and Dr. HyungSeok Han, who joined me in making this meaningful contribution.”
KAIST President Kwang Hyung Lee commented, “I deeply thank our alumni for achieving outstanding results on the world stage of technological competition and for generously giving back to their alma mater. This achievement demonstrates KAIST’s educational and research excellence and stands as meaningful evidence of the global competitiveness of Korea’s AI and security technologies. KAIST will continue to lead advanced AI and security innovation and do its utmost to nurture creative talent who will contribute to humanity and society.”
To encourage further alumni contributions, the KAIST Development Foundation is operating the Team KAIST (https://giving.kaist.ac.kr/ko/sub01/sub0103_1.php) campaign to promote alumni participation.
2025.11.24 View 349 -
Imdang Scholarship and Culture Foundation Donates 500 Million Won to Modernize KAIST's Space Research Infrastructure
< Photo of the Chung Mong-Hun Uri-Star Research Building at the Satellite Research Center >
KAIST announced on the Novemnber 21st that it received a donation of 500 million won from the Imdang Scholarship and Culture Foundation and will proceed with an environmental improvement project for the 'Chung Mong-Hun Uri-Star Research Building' at the Satellite Research Center on the main campus in Daejeon.
The Imdang Scholarship and Culture Foundation is a non-profit scholarship foundation established in 2005 by Chairwoman Moon-Hee Kim, the mother of Hyundai Group Chairwoman Jeong-Eun Hyun. Currently, Executive Director Ji-Yi Chung of Hyundai Movex, Chairwoman Hyun's eldest daughter, serves as the Chairwoman of the Foundation. The foundation has been carrying out various projects over three generations to promote education, culture, arts, sports, and nurture talent.
This donation from the Imdang Scholarship and Culture Foundation once again brings the special and long-standing relationship between KAIST and the Hyundai Group into the spotlight.
The 'Chung Mong-Hun Uri-Star Research Building,' located on the main KAIST campus in Daejeon, was established with a donation from the late Mong-Hun Chung, former Chairman of the Hyundai Group and husband of Chairwoman Hyun, to foster the development of domestic space research. This enabled the launch of the nation's first dedicated university-affiliated space research organization. Following this, Chairwoman Hyun also continued to show special interest and affection for research support projects. The research building was named its current name in 2008 to commemorate the 5th anniversary of the passing of the late Chairman Mong-Hun Chung. In this way, the partnership between Hyundai and KAIST is regarded as a healthy example of corporate social contribution, where a company participates in the development of the knowledge ecosystem and the nurturing of talent.
The KAIST Satellite Research Center, housed in the 'Chung Mong-Hun Uri-Star Research Building,' was established in 1989 as the nation's first dedicated university-affiliated space research organization. Starting with 'Uribyol-1,' which signaled the start of South Korea's space development, it has led the development of various satellites, including next-generation small satellites and ultra-small satellite constellations, based on independent domestic technology, growing into a world-class small satellite research institution.
Currently, about 80 researchers are stationed at the research building, dedicated to developing cutting-edge small satellite technology. However, the inconvenience of transporting research equipment due to the absence of an elevator and the lack of accessibility for mobility-impaired individuals have been persistent issues.
KAIST plans to use this donation to install an elevator connecting the basement floor to the 4th floor above ground. This will increase the efficiency of transporting research equipment while providing a convenient movement environment for both visitors and researchers.
Furthermore, the public relations hall, which has been operating since 2008, will be renovated into an experiential exhibition space, applying the latest digital display techniques to allow visitors to see KAIST's space research achievements and history at a glance. Visited by over 1,000 people annually, including domestic and international students, the general public, research institutions, businesses, and government officials, this space is expected to become a place for experiencing and sharing KAIST's space technology development process and future vision.
To commemorate this project and express gratitude for the sponsorship, our university will hold a plaque of appreciation ceremony at the KAIST Seoul Campus President's Office on Friday, November 21st, at 3:00 PM. Chairwoman Jeong-Eun Hyun of the Hyundai Group, President Kwang Hyung Lee of KAIST, and Director Jaeheung Han of the KAIST Space Science Research Institute attended the event to exchange expressions of mutual cooperation and gratitude.
Hyundai Group Chairwoman Jeong-Eun Hyun stated, "The late Chairman Mong-Hun Chung supported the development of the KAIST Satellite Research Center with his deep passion for science and space," and "I hope this environmental improvement project will carry on his legacy, contribute to the development of Korean space technology, and serve as an opportunity for more young talents to foster their dreams."
KAIST President Kwang Hyung Lee stated, "The Chung Mong-Hun Uri-Star Research Building is a symbolic space for the development of South Korea's space technology, and this environmental improvement project will serve as an opportunity to enhance both research efficiency and the value of public experience," adding, "The meaningful sponsorship from the Imdang Scholarship and Culture Foundation will be a great source of strength for KAIST's future space research development."
2025.11.21 View 387 -
Depression is Not Only a Disease of the Mind. KAIST Discovers the Immune-Brain Connection
<(From Left) Ph.D candidate Insook Ahn from KAIST, Professor Jinju Han from KAIST, (Upper Left) Yangsik Kim from Inhan University School of Medicine, Ph.D candidate Soyeon Chang(psychiatrist)>
Major depressive disorder (MDD) is characterized by a lowered mood and loss of interest, contributing not only to difficulties in academic and professional life but also as a major cause of suicide in South Korea. However, there are currently no objective biological markers that can be used for diagnosis or treatment. Amidst this, a research team from KAIST has revealed that depression is not merely a problem of the mind or brain, but is deeply connected to abnormalities in the body's overall immune response. They found that this immune abnormality affects brain function, and the 'Immune Neural Axis' imbalance is the core mechanism of depression, opening up the possibility for the discovery of new biomarkers and the development of new drugs for depression treatment.
KAIST announced on the November 20th that Professor Jinju Han's research team from the Graduate School of Medical Science and Engineering (GSMSE) at KAIST, in collaboration with Professor Yangsik Kim's research team (Ph.D., KAIST GSMSE) from Inha University School of Medicine, performed a multi-omics analysis combining plasma proteomic analysis, WBC single-cell analysis, and patient-derived brain organoids (mini-brains). This study focused on female patients with MDD who exhibited 'Atypical Features' (such as hypersomnia and overeating) and 'Psychotic Symptoms'(such as auditory hallucinations and idea of reference), which are different from typical depression symptoms, and who also had impaired reality judgment.
Sduio
■ "Immune Cells and Brain Function are Altered Together" A New Biological Clue for Depression
The research team simultaneously examined genetic changes in immune cells in the blood and changes in nervous-system-related proteins. The results confirmed a breakdown in the balance of immune-neural interaction in patients with depression.
MDD, especially in young women, often presents with atypical symptoms (hypersomnia, overeating, mood reactivity, etc.), which increases the risk of a later diagnosis of bipolar disorder. Furthermore, about 40% of patients are classified as treatment-resistant depression, showing no response to various antidepressants.
Consequently, there has been a continuous call for the development of new therapeutic strategies and the discovery of biomarkers based on immunity and metabolism, moving beyond the traditional drug-centric approach.
■ World's First Integration of "Leukocyte Single-Cell Analysis + Brain Organoid" A New Paradigm for Psychiatric Research
The research team presented the world's first precision medicine approach by integrating plasma proteomics, leukocyte single-cell transcriptome analysis, and analysis of brain organoids created from patient-derived induced pluripotent stem cells (iPSCs).
The results showed that patients with atypical depression exhibited high levels of stress, anxiety, and depression. Furthermore, proteins crucial for inter-neuronal signaling (DCLK3 and CALY) were significantly elevated compared to normal levels, and Complement Protein C5, which strongly enhances the body's immune response, was also increased. This indicates that both 'brain function' and 'immune function' are excessively activated and out of balance within the body.
This finding confirms a clue that depression is not merely a mood issue but is connected to biological changes occurring throughout the entire body. Upon examining the immune cells of depression patients, genetic changes were found that make inflammatory responses in the body occur more easily and strongly than usual. This implies that the entire bodily immune system is in a state of excessive activation, and this immune/inflammatory abnormality may influence the development of depression.
The patient-derived brain organoids showed accompanying growth retardation and abnormal neural development, supporting the possibility that immune abnormalities interact with changes in brain function to exacerbate the disease.
■ "Immune-Neural Axis Imbalance is the Core Mechanism of Atypical Depression"
This study integrated clinical data, single-cell omics, proteomics, and brain organoids to demonstrate that the 'Imbalance of the Immune-Neural Axis' is the core mechanism of MDD accompanied by atypical and psychotic symptoms.
<Integration of clinical symptoms, blood analysis, and patient-derived brain organoid analysis in women with major depressive disorder>
Professor Jinju Han stated, "This achievement presents a new precision medicine model for psychiatric research," adding, "We anticipate that this will actively lead to biomarker discovery and new drug development."
This accomplishment was published online in the world-renowned international scientific journal, Advanced Science, on October 31st.
※ Paper Title: Exploration of Novel Biomarkers through a Precision Medicine Approach Using Multi-omics and Brain Organoids in Patients with Atypical Depression and Psychotic Symptoms DOI: https://doi.org/10.1002/advs.202508383
※ Author Information: Soyeon Chang (Inha University, Co-First Author), Seok-Ho Choi, Jiyoung Lee, Yangsik Kim (Inha University, Corresponding Author), Insook Ahn (KAIST, Co-First Author), and Jinju Han (KAIST, Corresponding Author)
This research was supported by the National Research Foundation of Korea and the Korea Health Industry Development Institute.
2025.11.20 View 8741 -
Professor Sang Yup Lee Selected as IETI 'Laureate Distinguished Fellow'
<Professor Sang Yup Lee of the Department of Chemical and Biomolecular Engineering>
Professor Sang Yup Lee of KAIST Department of Chemical and Biomolecular Engineering has been selected as a 'Laureate Distinguished Fellow,' the highest rank of fellow, by the International Engineering and Technology Institute (IETI).
Professor Lee is a globally renowned biotechnologist who has been leading research on the sustainable production of bio-based chemicals, and he received the 'ENI Award' in 2018. With this selection, he stands shoulder-to-shoulder with the world's top scholars, including recipients of the Nobel, Fields, and Turing Prizes.
IETI is an international academic organization established in Hong Kong in 2015 to promote innovation and international cooperation in the fields of engineering, technology, and science. Each year, the institute selects researchers with significant academic influence worldwide and appoints them into three grades: Laureate Distinguished Fellow, Distinguished Fellow, and Fellow. Professor Lee has been named to the most prestigious grade among these.
<IETI 2025 Fellow Selection Photo>
A total of 70 new fellows were selected in 2025. Among them, 14 individuals were named Laureate Distinguished Fellows, which includes recipients of top honors such as the Nobel, Fields, and Turing Prizes. Besides Professor Lee, this group includes Dudley Herschbach of Harvard University (Nobel Prize in Chemistry), Vint Cerf of Google (Turing Award), and Shigefumi Mori of Kyoto University (Fields Medal).
IETI stated that the selection process involved a rigorous five-step procedure: nomination, qualification review, document screening, expert voting, and final evaluation. It also expressed hope that the newly appointed fellows will demonstrate academic leadership in their respective research fields and contribute to global scientific and technological innovation and the promotion of international cooperation.
2025.11.10 View 529 -
3D Worlds from Just a Few Phone Photos
<(From Left) Ph.D candidate Jumin Lee, Ph.D candidate Woo Jae Kim, Ph.D candidate Youngju Na, Ph.D candidate Kyu Beom Han, Professor Sung-eui Yoon>
Existing 3D scene reconstructions require a cumbersome process of precisely measuring physical spaces with LiDAR or 3D scanners, or correcting thousands of photos along with camera pose information. The research team at KAIST has overcome these limitations and introduced a technology enabling the reconstruction of 3D —from tabletop objects to outdoor scenes—with just two to three ordinary photographs. The breakthrough suggests a new paradigm in which spaces captured by camera can be immediately transformed into virtual environments.
KAIST announced on November 6 that the research team led by Professor Sung-Eui Yoon from the School of Computing has developed a new technology called SHARE (Shape-Ray Estimation), which can reconstruct high-quality 3D scenes using only ordinary images, without precise camera pose information.
Existing 3D reconstruction technology has been limited by the requirement of precise camera position and orientation information at the time of shooting to reproduce 3D scenes from a small number of images. This has necessitated specialized equipment or complex calibration processes, making real-world applications difficult and slowing widespread adoption.
To solve these problems, the research team developed a technology that constructs accurate 3D models by simultaneously estimating the 3D scene and the camera orientation using just two to three standard photographs. The technology has been recognized for its high efficiency and versatility, enabling rapid and precise reconstruction in real-world environments without additional training or complex calibration processes.
While existing methods calculate 3D structures from known camera poses, SHARE autonomously extracts spatial information from images themselves and infers both camera pose and scene structure. This enables stable 3D reconstruction without shape distortion by aligning multiple images taken from different positions into a single unified space.
<Representative Image of SHARE Technology>
"The SHARE technology is a breakthrough that dramatically lowers the barrier to entry for 3D reconstruction,” said Professor Sung-Eui Yoon. “It will enable the creation of high-quality content in various industries such as construction, media, and gaming using only a smartphone camera. It also has diverse application possibilities, such as building low-cost simulation environments in the fields of robotics and autonomous driving."
<SHARE Technology, Precise Camera Information and 3D Scene Prediction Technology>
Ph.D. Candidate Youngju Na and M.S candidate Taeyeon Kim participated as co-first authors on the research. The results were presented on September 17th at the IEEE International Conference on Image Processing (ICIP 2025), where the paper received the Best Student Paper Award.
The award, given to only one paper among 643 accepted papers this year—a selection rate of 0.16 percent—once again underscores the excellent research capabilities of the KAIST research team.
Paper Title: Pose-free 3D Gaussian Splatting via Shape-Ray Estimation, DOI: https://arxiv.org/abs/2505.22978
Award Information: https://www.linkedin.com/posts/ieeeicip_congratulations-to-the-icip-2025-best-activity-7374146976449335297-6hXz
This achievement was carried out with support from the Ministry of Science and ICT's SW Star Lab Project under the task 'Development of Perception, Action, and Interaction Algorithms for Unspecified Environments for Open World Robot Services.'
2025.11.10 View 762 -
KAIST's 'FluidGPT' Wins Grand Prize at the 2025 AI Champion Competition
<Commemorative Photo After Winning at the 2025 AI Champions Award Ceremony>
The era has begun where an AI assistant goes beyond simple conversation to directly view the screen, make decisions, and complete tasks such as hailing a taxi or booking an SRT ticket.
KAIST (President Kwang Hyung Lee) announced on the 6th that the AutoPhone Team (Fluidez, KAIST, Korea University, Sungkyunkwan University), led by Professor Insik Shin (CEO of Fluidez Co., Ltd.) of the School of Computing, was selected as the inaugural AI Champion (1st place) in the '2025 Artificial Intelligence Champion (AI Champion) Competition,' hosted by the Ministry of Science and ICT.
This competition is the nation's largest AI technology contest, comprehensively evaluating the innovativeness, social impact, and commercial potential of AI technology. With 630 teams participating nationwide, the AutoPhone Team claimed the top honor and will receive 3 billion Korean won in research and development funding.
The technology developed by the AutoPhone Team, 'FluidGPT,' is a fully autonomous AI agent that understands a user's voice command and enables the smartphone to independently run apps, click, input, and even complete payments.
For example, when a user says, "Book an SRT ticket from Seoul Station to Busan," or "Call a taxi," FluidGPT opens the actual app and sequentially performs the necessary steps to complete the request.
The core of this technology is its 'Non-Invasive (API-Free)' structure. Previously, calling a taxi using an app required directly connecting to the app's internal system (API communication) through the taxi app's API. In contrast, this technology does not modify the existing app's code or link an API. Instead, the AI directly recognizes and operates the screen (UI), acquiring the ability to use the smartphone just like a human.
As a result, FluidGPT presents a new paradigm—"AI that sees, judges, and moves a hand on behalf of a person"—and is evaluated as a core technology that will usher in the 'AI Phone Era.'
FluidGPT moves beyond simple voice assistance to implement the concept of 'Agentic AI' (Action-Oriented Artificial Intelligence), where the AI directly views the screen, makes decisions, and takes action. As a fully action-oriented system, the AI clicks app buttons, fills in input fields, and references data to autonomously achieve the user's objective, foreshadowing an innovation in how smartphones are used.
Professor In-sik Shin of the School of Computing shared his thoughts, stating, "AI is now evolving from conversation to action. FluidGPT is a technology that understands the user's words and autonomously executes actual apps, and it will be the starting point of the 'AI Phone Era.' The AutoPhone Team possesses world-class research capabilities, and we will contribute to the widespread adoption of AI services that everyone can easily use."
KAIST President Kwang Hyung Lee remarked, "This achievement is a representative example that demonstrates KAIST's vision for AI convergence," adding, "AI technology is entering the daily lives of citizens and leading a new wave of innovation." He further added, "KAIST will continue to lead research in future core technologies such as AI and semiconductors to bolster national competitiveness."
2025.11.06 View 878 -
KAIST Uncovers the Mechanism Behind Overactive Immune Cells
<(From Right) Professor Eui-Cheol Shin, Ph.D candidate So-Young Kim, Professor Su-Hyung Park, Professor Hyuk Soo Eun, Dr. Hoyoung Lee>
“Why do immune cells that are supposed to eliminate viruses suddenly turn against our own body?”
There are instances where killer T cells—which are meant to precisely remove virus-infected cells—malfunction like overheated engines, attacking even healthy cells and damaging tissues. A KAIST research team has now identified the key mechanism that regulates this excessive activation of killer T cells, offering new insights into controlling immune overreactions and developing therapies for immune-related diseases.
KAIST (President Kwang Hyung Lee) announced on November 5 that a research team led by Professors Eui-Cheol Shin and Su-Hyung Park from the Graduate School of Medical Science and Engineering, in collaboration with Professor Hyuk Soo Eun from Chungnam National University College of Medicine, has uncovered the molecular basis of nonspecific activation in killer T cells and proposed a new therapeutic strategy to control it.
Killer T cells (CD8⁺ T cells) selectively eliminate infected cells to prevent viral spread. However, when excessively activated, they can attack uninfected cells, causing inflammation and tissue damage. Such overactive immune responses can lead to severe viral infections and autoimmune diseases.
In 2018, Professor Shin’s team was the first in the world to discover that killer T cells can be nonspecifically activated by cytokines and randomly attack host cells—a phenomenon they termed “bystander activation of T cells”. The current study builds on that discovery by revealing the molecular mechanism driving this abnormal process.
The team focused on a cytokine called interleukin-15 (IL-15). Experiments showed that IL-15 can abnormally excite killer T cells by a bystander activation mechanism, causing them to attack uninfected host cells. However, when there is a concurrent antigen-specific stimulation, IL-15-induced bystander activation is suppressed.
The researchers further identified that this suppression occurs through an intracellular signaling process. When the concentration of calcium ions (Ca²⁺) changes, a protein called calcineurin activates, which in turn triggers a regulatory protein known as NFAT, suppressing IL-15-induced bystander activation of killer T cells. In other words, the calcineurin–NFAT pathway activated by antigen stimulation acts as a brake on overactivation by a bystander mechanism.
The team also discovered that some immunosuppressants, which are known to block the calcineurin pathway, may not always suppress immune responses—in certain contexts, they can instead promote IL-15-induced bystander activation of killer T cells. This finding underscores that not all immunosuppressants work the same way and that treatments must be carefully tailored to each patient’s immune response.
Through gene expression analysis, the researchers identified a gene set that increase only in abnormally activated killer T cells induced by IL-15 as markers. They further confirmed that these same markers were elevated in bystander killer T cells from patients with acute hepatitis A, suggesting that the markers could be used for disease diagnosis.
<In a normal immune response, killer T cells are activated by antigen stimulation and selectively eliminate only virus-infected cells, thereby controlling viral replication and promoting the patient’s rapid recovery. However, when killer T cells are nonspecifically overactivated by interleukin-15, they may randomly attack normal cells as well, causing excessive tissue damage and leading to severe disease. Future research may identify diseases in which such nonspecific hyperimmune responses occur, making it possible to develop new drugs to control them>
This study provides crucial clues for understanding the pathogenesis of various immune-related diseases, including severe viral infections, chronic inflammatory disorders, autoimmune diseases, and organ transplant rejection. It also paves the way for developing novel immunoregulatory therapies targeting IL-15 signaling.
Professor Eui-Cheol Shin explained that, “this study shows that killer T cells are not merely defenders—they can transform into ‘nonspecific attackers’ depending on the inflammatory environment. By precisely regulating this abnormal activation, we may be able to develop new treatments for intractable immune diseases.”
This research was published in the journal Immunity on October 31, with Dr. Hoyoung Lee and Ph.D. candidate So-Young Kim as co–first authors.
Title: “TCR signaling via NFATc1 constrains IL-15-induced bystander activation of human memory CD8⁺ T cells”, DOI: doi.org/10.1016/j.immuni.2025.10.002
The study was supported by the National Research Foundation of Korea (NRF), the Korea Health Industry Development Institute (KHIDI), and the Institute for Basic Science (IBS).
2025.11.06 View 919 -
KAIST Welcomes NVIDIA CEO Jensen Huang’s Cooperation Initiative “Strengthening Collaboration in AI and Robotics Innovation”
KAIST (President Kwang Hyung Lee) announced its strong support for the meeting between Korean President Jae-myung Lee and NVIDIA CEO Jensen Huang on October 31, where both sides discussed strategies to advance Korea’s AI ecosystem.
KAIST stated that the meeting marks “a significant turning point for Korea’s AI innovation and global cooperation.” During the discussion, NVIDIA, a global leader in artificial intelligence, explored partnership opportunities with the Korean government to realize its vision of becoming one of the “Top Three AI Nations” and achieving an “AI-based Society.”
NVIDIA also unveiled plans to expand Korea’s AI computing infrastructure by introducing more than 260,000 of its latest GPUs, while strengthening technology cooperation to meet both public and private sector AI demand.
The meeting covered a wide range of potential collaborations, including:
Building advanced AI infrastructure, joint research and technology cooperation in physical AI (AI in robotics, autonomous systems, and manufacturing), and
expanding AI talent development and startup support programs.
At the APEC CEO Summit, NVIDIA CEO Jensen Huang said, “NVIDIA’s goal is not only to provide hardware to Korea, but to help build a sustainable AI ecosystem. And we will work closely with AI researchers in Korea universities, amazing university like KAIST, startups, the government, and research institutions to become the AI Frontier.”
He further emphasized that, “The evolution of AI will inevitably converge with robotics. Realizing autonomous robots and robotic factories that can work alongside humans represents the next stage and ultimate goal of AI technology.”
As Korea’s leading AI research institution, KAIST has long collaborated with government and industry partners in key areas such as AI semiconductors, autonomous driving, robotics, digital twins, and quantum computing.
Building on this dialogue, KAIST plans to further strengthen its partnership with NVIDIA and major domestic industries through next-generation AI semiconductor and HBM (High Bandwidth Memory) research, physical AI applications in robotics and autonomous systems, hands-on AI education and talent development, and global open innovation through academia–industry joint research.
KAIST President Kwang Hyung Lee stated: “AI is the core driver of national competitiveness. Jensen Huang’s visit represents a symbolic milestone as Korea emerges as a global leader in AI.” He added: “Huang’s vision of integrating AI and robotics aligns perfectly with KAIST’s research direction. KAIST will continue to work closely with NVIDIA to build an AI innovation ecosystem that benefits humanity.”
Following CEO Huang’s proposal, KAIST will further concretize its collaboration with NVIDIA and expand partnerships with both global enterprises and domestic industries.
Through these efforts, KAIST aims to advance AI research clusters, develop next-generation AI computing platforms, nurture AI professionals, and foster a vibrant startup ecosystem, contributing continuously to Korea’s global AI competitiveness.
2025.11.03 View 943 -
Robot-Operated Space Station Construction Goal... 'In-space Servicing and Manufacturing Research Center' Launched
<Plaque Handover Ceremony. (From left) Jae-Hung Han, Director of the Space Research Institute, Ju-won Kang, Head of Engineering Group at the National Research Foundation of Korea Basic Research Headquarters>
KAIST's Space Research Institute announced on the 24th of October that it officially launched the 'Innovative Research Center for the Development of Core Technologies in In-space Servicing and Manufacturing (ISMRC)' at the KAIST Academic Cultural Center on Friday, October 24. About 150 officials from major organizations, including the Korea Aerospace Administration, the National Research Foundation of Korea, and Daejeon Metropolitan City, as well as domestic and foreign space experts, attended the opening ceremony to discuss future cooperation measures. The 'KAIST In-space Servicing and Manufacturing Research Center (ISMRC)' is a large-scale research hub selected for the Ministry of Science and ICT's 2025 Basic Research Project, with a total of 71.2 billion KRW long-term project planned over the next 10 years, including 50 billion KRW in national funding. Daejeon City will also provide a total of 3.6 billion KRW, with 400 million KRW annually starting from 2026. The research goals are to secure core technologies for next-generation space exploration, including: ▲ Construction of Unmanned Space Stations, ▲ Robotics-based In-space Manufacturing, and ▲ Resource Recovery Technology. A team of 14 KAIST professors, led by Director Jae-Hung Han, will spearhead the research, with major domestic and foreign space companies and research institutions participating in joint research. As the 'New Space' era fully commences globally, the In-space Servicing and Manufacturing industry is projected to grow to tens of trillions of Korean won by 2030, driven by the reduction of launch costs and the expansion of private sector participation. This field is evaluated as a core area that will fundamentally change the way humanity engages in space activities, including extending satellite lifespan, on-orbit maintenance and operation, and securing and manufacturing resources in space. Meanwhile, an international symposium was held for two days on October 23-24 at the KAIST Academic Cultural Center and KI Building, coinciding with the opening ceremony.
<Director Jae-Hung Han of the Space Research Institute presenting>
The symposium was composed of a total of six sessions, including: ▲ Exchange Meeting on Additive Manufacturing Tecnology for Aerospace, ▲ International Workshop on Aerospace Composites, ▲ Workshop on Swarm Satellite Development, and ▲ Workshop on In-space Servicing and Manufacturing Robotics. Major domestic and foreign institutions and experts, including the Korea Aerospace Research Institute, Japan Advanced Institute of Science and Technology, and California Institute of Technology (Caltech), attended to discuss the future direction of next-generation space technology development and international cooperation measures. Cheol-woong Son, Director-General of Future Strategy Industry Office at Daejeon City, said, "We will develop the Innovative Research Center into a Daejeon-type space industry innovation platform with KAIST," and "Daejeon City will concentrate its capabilities to help local businesses grow and establish Daejeon as the central city for the Republic of Korea's space industry." Jae-Hung Han, Director of the KAIST Space Research Institute, said, "We will lead the core technologies for in-space servicing and manufacturing through cooperation between industry, academia, research institutes, and government, and contribute to the establishment of a private sector-focused industrial ecosystem," adding, "KAIST will grow into a comprehensive research hub that encompasses R&D, talent nurturing, and technology commercialization."
<Group Photo of Participants at the Opening Ceremony of the In-space Servicing and Manufacturing Research Center>
Kwang Hyung Lee, President of KAIST, said, "The field of in-space servicing and manufacturing is a core area that will change the paradigm of the future space industry," and "KAIST will lead the Republic of Korea to become the center for opening a new era of the space industry through innovative technology development and global cooperation." KAIST plans to perform the role of breaking down the boundaries between academia and industry, focusing on these technologies, and laying the foundation for next-generation space activities.
2025.10.24 View 1337