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X-ORIGINAL-URL:https://www.ibs.re.kr/bimag
X-WR-CALDESC:Events for Biomedical Mathematics Group
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BEGIN:VTIMEZONE
TZID:Asia/Seoul
BEGIN:STANDARD
TZOFFSETFROM:+0900
TZOFFSETTO:+0900
TZNAME:KST
DTSTART:20240101T000000
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BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20260102T100000
DTEND;TZID=Asia/Seoul:20260102T113000
DTSTAMP:20260422T074007
CREATED:20251231T002614Z
LAST-MODIFIED:20251231T002614Z
UID:12076-1767348000-1767353400@www.ibs.re.kr
SUMMARY:Seasonal timing and interindividual differences in shiftwork adaptation - Kang Min Lee
DESCRIPTION:In this talk\, we discuss the paper “Seasonal timing and interindividual differences in shiftwork adaptation” by R. Kim et al.\, npj digital medicine\, 2025. \nAbstract  \nMillions of shift workers in the U.S. face an increased risk of depression\, cancer\, and metabolic disease\, yet individual responses to shift work vary widely. We find that a conserved biological system of morning and evening oscillators\, which evolved for seasonal timing\, may contribute to these interindividual differences. In this study\, we analyze seasonality in medical interns working shifts\, revealing that summer-winter variation correlates with increased circadian misalignment after shift work. Mathematical modeling suggests that seasonal timing influences the rate of adaptation to new schedules\, predicting differential effects on morning and evening oscillators. Additionally\, we examine genetic polymorphisms linked to seasonality in animals and find that human variants can impact how quickly circadian rhythms respond to schedule changes. Based on our findings\, we hypothesize that the vast interindividual differences in shift work adaptation—critical for shift worker health—can in part be explained by biological mechanisms for seasonal timing.
URL:https://www.ibs.re.kr/bimag/event/seasonal-timing-and-interindividual-differences-in-shiftwork-adaptation-kang-min-lee/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20251226T100000
DTEND;TZID=Asia/Seoul:20251226T120000
DTSTAMP:20260422T074007
CREATED:20251026T141349Z
LAST-MODIFIED:20251226T002150Z
UID:11798-1766743200-1766750400@www.ibs.re.kr
SUMMARY:N-BEATS: Neural basis expansion analysis for interpretable time series forecasting - Jinwoo Hyun
DESCRIPTION:In this talk\, we discuss the paper “N-BEATS: Neural basis expansion analysis for interpretable time series forecasting” by B. Oreshkin et al.\, ICLR\, 2020. \nAbstract \nWe focus on solving the univariate times series point forecasting problem using deep learning. We propose a deep neural architecture based on backward and forward residual links and a very deep stack of fully-connected layers. The architecture has a number of desirable properties\, being interpretable\, applicable without modification to a wide array of target domains\, and fast to train. We test the proposed architecture on several well-known datasets\, including M3\, M4 and TOURISM competition datasets containing time series from diverse domains. We demonstrate state-of-the-art performance for two configurations of N-BEATS for all the datasets\, improving forecast accuracy by 11% over a statistical benchmark and by 3% over last year’s winner of the M4 competition\, a domain-adjusted hand-crafted hybrid between neural network and statistical time series models. The first configuration of our model does not employ any time-series-specific components and its performance on heterogeneous datasets strongly suggests that\, contrarily to received wisdom\, deep learning primitives such as residual blocks are by themselves sufficient to solve a wide range of forecasting problems. Finally\, we demonstrate how the proposed architecture can be augmented to provide outputs that are interpretable without considerable loss in accuracy.
URL:https://www.ibs.re.kr/bimag/event/journal-club-jinwoo-hyun/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20251212T110000
DTEND;TZID=Asia/Seoul:20251212T123000
DTSTAMP:20260422T074007
CREATED:20251026T141250Z
LAST-MODIFIED:20251215T043112Z
UID:11796-1765537200-1765542600@www.ibs.re.kr
SUMMARY:Quantifying interventional causality by knockoff operation - Yun Min Song
DESCRIPTION:In this talk\, we discuss the paper “Causal disentanglement for single-cell representations and controllable counterfactual generation” by Yicheng Gao et al.\, Nature Communications\, 2025. \nAbstract  \nConducting disentanglement learning on single-cell omics data offers a promising alternative to traditional black-box representation learning by separating the semantic concepts embedded in a biological process. We present CausCell\, which incorporates the factual information about causal relationships among disentangled concepts within a diffusion model to generate more reliable disentangled cellular representations\, with the aim of increasing the explainability\, generalizability and controllability of single-cell data\, including spatial-temporal omics data\, relative to those of the existing black-box representation learning models. Two quantitative evaluation scenarios\, i.e.\, disentanglement and reconstruction\, are presented to conduct the first comprehensive single-cell disentanglement learning benchmark\, which demonstrates that CausCell outperforms the state-of-the-art methods in both scenarios. Additionally\, CausCell can implement controllable generation by intervening with the concepts of single-cell data when given a causal structure. It also has the potential to uncover biological insights by generating counterfactuals from small and noisy single-cell datasets.
URL:https://www.ibs.re.kr/bimag/event/journal-club-yun-min-song/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20251121T100000
DTEND;TZID=Asia/Seoul:20251121T120000
DTSTAMP:20260422T074007
CREATED:20251026T141157Z
LAST-MODIFIED:20251121T000249Z
UID:11794-1763719200-1763726400@www.ibs.re.kr
SUMMARY:Modeling personalized heart rate response to exercise and environmental factors with wearables data - Dongju Lim
DESCRIPTION:In this talk\, we discuss the paper “Modeling personalized heart rate response to exercise and environmental factors with wearables data” by Nazaret et al.\, npj digital medicine\, 2023. \nAbstract \nHeart rate (HR) response to workout intensity re ects tness and cardiorespiratory health. Physiological models have been developed to describe such heart rate dynamics and characterize cardiorespiratory tness. However\, these models have been limited to small studies in controlled lab environments and are challenging to apply to noisy—but ubiquitous—data from wearables. We propose a hybrid approach that combines a physiological model with exible neural network components to learn a personalized\, multidimensional representation of tness. The physiological model describes the evolution of heart rate during exercise using ordinary differential equations (ODEs). ODE parameters are dynamically derived via a neural network connecting personalized representations to external environmental factors\, from area topography to weather and instantaneous workout\nintensity. Our approach ef ciently ts the hybrid model to a large set of 270\,707 workouts collected from wearables of 7465 users from the Apple Heart and Movement Study. The resulting model produces tness representations that accurately predict full HR response to exercise intensity in future workouts\, with a per-workout median error of 6.1 BPM [4.4–8.8 IQR]. We further demonstrate that the learned representations correlate with traditional metrics of cardiorespiratory tness\, such as VO2 max (explained variance\n0.81 ± 0.003). Lastly\, we illustrate how our model is naturally interpretable and explicitly describes the effects of environmental factors such as temperature and humidity on heart rate\, e.g.\, high temperatures can increase heart rate by 10%. Combining physiological ODEs with exible neural networks can yield interpretable\, robust\, and expressive models for health applications.
URL:https://www.ibs.re.kr/bimag/event/journal-club-dongju-lim/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20251107T100000
DTEND;TZID=Asia/Seoul:20251107T120000
DTSTAMP:20260422T074007
CREATED:20251026T141100Z
LAST-MODIFIED:20251107T000601Z
UID:11791-1762509600-1762516800@www.ibs.re.kr
SUMMARY:Principled PCA separates signal from noise in omics count data - Hyun Kim
DESCRIPTION:In this talk\, we discuss the paper “Principled PCA separates signal from noise in omics count data” by Jay S. Stanley III et al.\, bioarxiv\, 2025.  \nAbstract \nPrincipal component analysis (PCA) is indispensable for processing high-throughput omics datasets\, as it can extract meaningful biological variability while minimizing the influence of noise. However\, the suitability of PCA is contingent on appropriate normalization and transformation of count data\, and accurate selection of the number of principal components; improper choices can result in the loss of biological information or corruption of the signal due to excessive noise. Typical approaches to these challenges rely on heuristics that lack theoretical foundations. In this work\, we present Biwhitened PCA (BiPCA)\, a theoretically grounded framework for rank estimation and data denoising across a wide range of omics modalities. BiPCA overcomes a fundamental difficulty with handling count noise in omics data by adaptively rescaling the rows and columns – a rigorous procedure that standardizes the noise variances across both dimensions. Through simulations and analysis of over 100 datasets spanning seven omics modalities\, we demonstrate that BiPCA reliably recovers the data rank and enhances the biological interpretability of count data. In particular\, BiPCA enhances marker gene expression\, preserves cell neighborhoods\, and mitigates batch effects. Our results establish BiPCA as a robust and versatile framework for high-throughput count data analysis.
URL:https://www.ibs.re.kr/bimag/event/from-noise-to-models-to-numbers-evaluating-negative-binomial-models-and-parameter-estimations-in-single-cell-rna-seq-hyun-kim/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20251031T090000
DTEND;TZID=Asia/Seoul:20251031T103000
DTSTAMP:20260422T074007
CREATED:20251004T064151Z
LAST-MODIFIED:20251023T035154Z
UID:11754-1761901200-1761906600@www.ibs.re.kr
SUMMARY:Dosing Time of Day Impacts the Safety of Antiarrhythmic Drugs in a Computational Model of Cardiac Electrophysiology - Chitaranjan Mahapatra
DESCRIPTION:In this talk\, we discuss the paper “Dosing Time of Day Impacts the Safety of Antiarrhythmic Drugs in a Computational Model of Cardiac Electrophysiology” by Ning Wei and Casey O Diekman\, J. Biol. Rhythms\, 2025.  \nAbstract \nCircadian clocks regulate many aspects of human physiology\, including cardiovascular function and drug metabolism. Administering drugs at optimal times of the day may enhance effectiveness and reduce side effects. Certain cardiac antiarrhythmic drugs have been withdrawn from the market due to unexpected proarrhythmic effects such as fatal Torsade de Pointes (TdP) ventricular tachycardia. The Comprehensive in vitro Proarrhythmia Assay (CiPA) is a recent global initiative to create guidelines for the assessment of drug-induced arrhythmias that recommends a central role for computational modeling of ion channels and in silico evaluation of compounds for TdP risk. We simulated circadian regulation of cardiac excitability and explored how dosing time of day affects TdP risk for 11 drugs previously classified into risk categories by CiPA. The model predicts that a high-risk drug taken at the most optimal time of day may actually be safer than a low-risk drug taken at the least optimal time of day. Based on these proof-of-concept results\, we advocate for the incorporation of circadian clock modeling into the CiPA paradigm for assessing drug-induced TdP risk. Since cardiotoxicity is the leading cause of drug discontinuation\, modeling cardiac-related chronopharmacology has significant potential to improve therapeutic outcomes.
URL:https://www.ibs.re.kr/bimag/event/dosing-time-of-day-impacts-the-safety-of-antiarrhythmic-drugs-in-a-computational-model-of-cardiac-electrophysiology-chitaranjan-mahapatra/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20251024T100000
DTEND;TZID=Asia/Seoul:20251024T120000
DTSTAMP:20260422T074007
CREATED:20250928T144047Z
LAST-MODIFIED:20251023T035250Z
UID:11629-1761300000-1761307200@www.ibs.re.kr
SUMMARY:Dynamical Mean-Field Theory of Complex Systems on Sparse Directed Networks - Gyuyoung Hwang
DESCRIPTION:In this talk\, we discuss the paper “Dynamical Mean-Field Theory of Complex Systems on Sparse Directed Networks” by Fernando L. Metz\, Phys. Rev. Letters\, 2025. \nAbstract \nAlthough real-world complex systems typically interact through sparse and heterogeneous networks\, analytic solutions of their dynamics are limited to models with all-to-all interactions. Here\, we solve the dynamics of a broad range of nonlinear models of complex systems on sparse directed networks with a random structure. By generalizing dynamical mean-field theory to sparse systems\, we derive an exact equation for the path probability describing the effective dynamics of a single degree of freedom. Our general solution applies to key models in the study of neural networks\, ecosystems\, epidemic spreading\, and synchronization. Using the population dynamics algorithm\, we solve the path-probability equation to determine the phase diagram of a seminal neural network model in the sparse regime\, showing that this model undergoes a transition from a fixed-point phase to chaos as a function of the network topology.
URL:https://www.ibs.re.kr/bimag/event/dynamical-mean-field-theory-of-complex-systems-on-sparse-directed-networks-gyuyoung-hwang/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20251017T100000
DTEND;TZID=Asia/Seoul:20251017T120000
DTSTAMP:20260422T074007
CREATED:20250928T143709Z
LAST-MODIFIED:20251004T064334Z
UID:11627-1760695200-1760702400@www.ibs.re.kr
SUMMARY:Simulating the Spread of Infection in Networks with Quantum Computers - Shingo Gibo
DESCRIPTION:In this talk\, we discuss the paper “Simulating the Spread of Infection in Networks with Quantum Computers” by Xiaoyang Wang\, Yinchenguang Lyu\, Changyu Yao and Xiao Yuan\, Physical Review Applied\, vol.19\, 064035 (2023). \nAbstract \nWe propose to use quantum computers to simulate infection spreading in networks. We first show the analogy between the infection distribution and spin-lattice configurations with Ising-type interactions. Then\, since the spreading process can be modeled as a classical Markovian process\, we show that the spreading process can be simulated using the evolution of a quantum thermal dynamic model with a parameterized Hamiltonian. In particular\, we analytically and numerically analyze the evolution behavior of the Hamiltonian\, and prove that the evolution simulates a classical Markovian process\, which describes the well-known epidemiological stochastic susceptible and infectious (SI) model. A practical method to determine the parameters of the thermal dynamic Hamiltonian from epidemiological inputs is exhibited. As an example\, we simulate the infection spreading process of the SARS-Cov-2 variant Omicron in a small-world network.
URL:https://www.ibs.re.kr/bimag/event/simulating-the-spread-of-infection-in-networks-with-quantum-computers-shingo-gibo/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250926T100000
DTEND;TZID=Asia/Seoul:20250926T113000
DTSTAMP:20260422T074007
CREATED:20250915T083322Z
LAST-MODIFIED:20250924T001304Z
UID:11589-1758880800-1758886200@www.ibs.re.kr
SUMMARY:Tackling inter-subject variability in smartwatch data using factorization models - Myna Lim
DESCRIPTION:In this talk\, we discuss the paper “Tackling inter-subject variability in smartwatch data using factorization models” by Arman Naseri et. al\, Scientific Reports\, 2025. \nAbstract \nSmartwatches enable longitudinal and continuous data acquisition. This has the potential to remotely monitor (changes) of the health of users. However\, differences among subjects (inter-subject variability) limit a model to generalize to unseen subjects. This study focused on binary classification tasks using heart rate and step counter from smartwatches\, including night/day and inactive/active classification\, as well as sleep and SpO2-related (oxygen saturation) tasks. To address inter-subject variability\, we explored different transforming and normalization regimes for time series including per-subject and population-based strategies. We propose a modified factorized autoencoder\, which separates the data into two latent spaces capturing class-specific and subject-specific information. Our proposed generalized factorized autoencoder and triplet factorized autoencoder improved classification accuracy over the baseline from 74.8 (± 10.5) to 83.1 (± 5.1) and 83.4 (± 5.3)\, respectively\, for night/day classification\, gains for inactive/active classification were modest\, improving from 84.3 (± 9.4) to 86.9 (± 4.4) and 86.6 (± 4.3)\, respectively. Our study highlights challenges of handling inter-subject variability in smartwatch data and how factorization models can be used to enable more robust and personalized health monitoring solutions for diverse populations.
URL:https://www.ibs.re.kr/bimag/event/tackling-inter-subject-variability-in-smartwatch-data-using-factorization-models-myna-lim/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250919T160000
DTEND;TZID=Asia/Seoul:20250919T180000
DTSTAMP:20260422T074007
CREATED:20250825T081133Z
LAST-MODIFIED:20250901T020244Z
UID:11435-1758297600-1758304800@www.ibs.re.kr
SUMMARY:SCassist: An AI Based Workflow Assistant for Single-Cell Analysis - Aqsa Awan
DESCRIPTION:In this talk\, we discuss the paper “SCassist: An AI Based Workflow Assistant for Single-Cell Analysis ” by Vijayaraj Nagarajan et al.\, bioarxiv\, 2025.  \nAbstract \nSingle-cell RNA sequencing (scRNA-seq) data analysis often involves complex iterative workflow\, requiring significant expertise and time. To navigate this complexity\, we have developed SCassist\, an R package that leverages the power of the large language models (LLM’s) to guide and enhance scRNA-seq analysis. SCassist integrates LLM’s into key workflow steps\, to analyze user data and provide relevant recommendations for filtering\, normalization and clustering parameters. It also provides LLM guided insightful interpretations of variable features and principal components\, along with cell type annotations and enrichment analysis. SCassist provides intelligent assistance using popular LLM’s like Google’s Gemini\, OpenAI’s GPT and Meta’s Llama3\, making scRNA-seq analysis accessible to researchers at all levels.
URL:https://www.ibs.re.kr/bimag/event/scassist-an-ai-based-workflow-assistant-for-single-cell-analysis-aqsa-awan/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250912T140000
DTEND;TZID=Asia/Seoul:20250912T160000
DTSTAMP:20260422T074007
CREATED:20250825T081619Z
LAST-MODIFIED:20250910T002342Z
UID:11438-1757685600-1757692800@www.ibs.re.kr
SUMMARY:Decomposing causality into its synergistic\, unique\, and redundant components - Olive Cawiding
DESCRIPTION:In this talk\, we discuss the paper “Decomposing causality into its synergistic\, unique\, and redundant components” by Álvaro Martínez-Sánchez et al.\, Nature Communications\, 2024. \nAbstract \nCausality lies at the heart of scientific inquiry\, serving as the fundamental basis for understanding interactions among variables in physical systems. Despite its central role\, current methods for causal inference face significant challenges due to nonlinear dependencies\, stochastic interactions\, self-causation\, collider effects\, and influences from exogenous factors\, among others. While existing methods can effectively address some of these challenges\, no single approach has successfully integrated all these aspects. Here\, we address these challenges with SURD: Synergistic-Unique-Redundant Decomposition of causality. SURD quantifies causality as the increments of redundant\, unique\, and synergistic information gained about future events from past observations. The formulation is non-intrusive and applicable to both computational and experimental investigations\, even when samples are scarce. We benchmark SURD in scenarios that pose significant challenges for causal inference and demonstrate that it offers a more reliable quantification of causality compared to previous methods.
URL:https://www.ibs.re.kr/bimag/event/data-driven-model-discovery-and-model-selection-for-noisy-biological-systems-olive-cawiding/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250905T140000
DTEND;TZID=Asia/Seoul:20250905T160000
DTSTAMP:20260422T074007
CREATED:20250825T080853Z
LAST-MODIFIED:20250901T020216Z
UID:11433-1757080800-1757088000@www.ibs.re.kr
SUMMARY:Physics-constrained neural ordinary differential equation models to discover and predict microbial community dynamics - Kang Min Lee
DESCRIPTION:In this talk\, we discuss the paper “Physics-constrained neural ordinary differential equation models to discover and predict microbial community dynamics” by J. Thompson et al.\, bioarxiv\, 2025. \nAbstract \nMicrobial communities play essential roles in shaping ecosystem functions and predictive modeling frameworks are crucial for understanding\, controlling\, and harnessing their properties. Competition and cross-feeding of metabolites drives microbiome dynamics and functions. Existing mechanistic models that capture metabolite-mediated interactions in microbial communities have limited flexibility due to rigid assumptions. While machine learning models provide flexibility\, they require large datasets\, are challenging to interpret\, and can over-fit to experimental noise. To overcome these limitations\, we develop a physics-constrained machine learning model\, which we call the Neural Species Mediator (NSM)\, that combines a mechanistic model of metabolite dynamics with a machine learning component. The NSM is more accurate than mechanistic or machine learning components on experimental datasets and provides insights into direct biological interactions. In summary\, embedding a neural network into a mechanistic model of microbial community dynamics improves prediction performance and interpretability compared to its constituent mechanistic or machine learning components.
URL:https://www.ibs.re.kr/bimag/event/physics-constrained-neural-ordinary-differential-equation-models-to-discover-and-predict-microbial-community-dynamics-kang-min-lee/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250829T140000
DTEND;TZID=Asia/Seoul:20250829T160000
DTSTAMP:20260422T074007
CREATED:20250727T024418Z
LAST-MODIFIED:20250727T024418Z
UID:11348-1756476000-1756483200@www.ibs.re.kr
SUMMARY:Binning as a Pretext Task: Improving Self-Supervised Learning in Tabular Domains - Jinwoo Hyun
DESCRIPTION:In this talk\, we discuss the paper “Binning as a Pretext Task: Improving Self-Supervised Learning in Tabular Domains” by K. Lee. \nAbstract \nThe ability of deep networks to learn superior representations hinges on leveraging the proper inductive biases\, considering the inherent properties of datasets. In tabular domains\, it is critical to effectively handle heterogeneous features (both categorical and numerical) in a unified manner and to grasp irregular functions like piecewise constant functions. To address the challenges in the self-supervised learning framework\, we propose a novel pretext task based on the classical binning method. The idea is straightforward: reconstructing the bin indices (either orders or classes) rather than the original values. This pretext task provides the encoder with an inductive bias to capture the irregular dependencies\, mapping from continuous inputs to discretized bins\, and mitigates the feature heterogeneity by setting all features to have category-type targets. Our empirical investigations ascertain several advantages of binning: compatibility with encoder architecture and additional modifications\, standardizing all features into equal sets\, grouping similar values within a feature\, and providing ordering information. Comprehensive evaluations across diverse tabular datasets corroborate that our method consistently improves tabular representation learning performance for a wide range of downstream tasks. The codes are available in the supplementary material.
URL:https://www.ibs.re.kr/bimag/event/binning-as-a-pretext-task-improving-self-supervised-learning-in-tabular-domains-jinwoo-hyun/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250822T153000
DTEND;TZID=Asia/Seoul:20250822T173000
DTSTAMP:20260422T074007
CREATED:20250803T065046Z
LAST-MODIFIED:20250819T002937Z
UID:11366-1755876600-1755883800@www.ibs.re.kr
SUMMARY:Statistical method scDEED for detecting dubious 2D single-cell embeddings and optimizing t-SNE and UMAP hyperparameters - Kevin Spinicci
DESCRIPTION:In this talk\, we discuss the paper “Statistical method scDEED for detecting dubious 2D single-cell embeddings and optimizing t-SNE and UMAP hyperparameters” by L. Xia et.al. Nature Communications\, 2024. \nAbstract \nTwo-dimensional (2D) embedding methods are crucial for single-cell data visualization. Popular methods such as t-distributed stochastic neighbor embedding (t-SNE) and uniform manifold approximation and projection (UMAP) are commonly used for visualizing cell clusters; however\, it is well known that t-SNE and UMAP’s 2D embeddings might not reliably inform the similarities among cell clusters. Motivated by this challenge\, we present a statistical method\, scDEED\, for detecting dubious cell embeddings output by a 2D-embedding method. By calculating a reliability score for every cell embedding based on the similarity between the cell’s 2D-embedding neighbors and pre-embedding neighbors\, scDEED identifies the cell embeddings with low reliability scores as dubious and those with high reliability scores as trustworthy. Moreover\, by minimizing the number of dubious cell embeddings\, scDEED provides intuitive guidance for optimizing the hyperparameters of an embedding method. We show the effectiveness of scDEED on multiple datasets for detecting dubious cell embeddings and optimizing the hyperparameters of t-SNE and UMAP.
URL:https://www.ibs.re.kr/bimag/event/context-aware-deconvolution-of-cell-cell-communication-with-tensor-cell2cell-kevin-spinicci/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250808T140000
DTEND;TZID=Asia/Seoul:20250808T160000
DTSTAMP:20260422T074007
CREATED:20250727T024732Z
LAST-MODIFIED:20250727T024732Z
UID:11351-1754661600-1754668800@www.ibs.re.kr
SUMMARY:Circadian rhythm analysis using wearable-based accelerometry as a digital biomarker of aging and healthspan - Yun Min Song
DESCRIPTION:In this talk\, we discuss the paper “Circadian rhythm analysis using wearable-based accelerometry as a digital biomarker of aging and healthspan” by J. Shim et.al.\, npj digital medicine\, 2024. \nAbstract \nRecognizing the pivotal role of circadian rhythm in the human aging process and its scalability through wearables\, we introduce CosinorAge\, a digital biomarker of aging developed from wearable-derived circadian rhythmicity from 80\,000 midlife and older adults in the UK and US. A one-year increase in\nCosinorAge corresponded to 8–12% higher all-cause and cause-specific mortality risks and 3–14% increased prospective incidences of age-related diseases. CosinorAge also captured a non-linear decline in resilience and physical functioning\, evidenced by an 8–33% reduction in self-rated health\nand a 3–23% decline in health-related quality of life score\, adjusting for covariates and multiple testing. The associations were robust in sensitivity analyses and external validation using an independent cohort from a disparate geographical region using a different wearable device. Moreover\, we\nillustrated a heterogeneous impact of circadian parameters associated with biological aging\, with young (<45 years) and fast agers experiencing a substantially delayed acrophase with a 25-minute difference in peak timing compared to slow agers\, diminishing to a 7-minute difference in older adults\n(>65 years). We demonstrated a significant enhancement in the predictive performance when integrating circadian rhythmicity in the estimation of biological aging over physical activity. Our findings underscore CosinorAge’s potential as a scalable\, economic\, and digital solution for promoting healthy longevity\, elucidating the critical and multifaceted circadian rhythmicity in aging processes. Consequently\, our research contributes to advancing preventive measures in digital medicine.
URL:https://www.ibs.re.kr/bimag/event/circadian-rhythm-analysis-using-wearable-based-accelerometry-as-a-digital-biomarker-of-aging-and-healthspan-yun-min-song/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250801T140000
DTEND;TZID=Asia/Seoul:20250801T160000
DTSTAMP:20260422T074007
CREATED:20250727T024030Z
LAST-MODIFIED:20250727T024047Z
UID:11346-1754056800-1754064000@www.ibs.re.kr
SUMMARY:Quantifying the energy landscape of high-dimensional oscillatory systems by diffusion decomposition - Eui Min Jeong
DESCRIPTION:In this talk\, we discuss the paper “Quantifying the energy landscape of high-dimensional oscillatory systems by diffusion decomposition” by S. Bian et.al.\, Cell Reports Physical Science\, 2025. \nAbstract \nHigh-dimensional networks producing oscillatory dynamics are ubiquitous in biological systems. Unraveling the mechanism of oscillatory dynamics in biological networks with stochastic perturbations becomes of paramount significance. Although the classical energy landscape theory provides a tool to study this problem in multistable systems and explain cellular functions\, it remains challenging to accurately quantify the landscape for high-dimensional oscillatory systems. Here\, we propose an approach called the diffusion decomposition of Gaussian approximation (DDGA). We demonstrate the efficacy of the DDGA in quantifying the energy landscape of oscillatory systems and corresponding stochastic dynamics in comparison with existing approaches. By further applying the DDGA to high-dimensional biological networks\, we are able to uncover more intricate biological mechanisms efficiently\, which deepens our understanding of cellular functions.
URL:https://www.ibs.re.kr/bimag/event/quantifying-the-energy-landscape-of-high-dimensional-oscillatory-systems-by-diffusion-decomposition-eui-min-jeong/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250725T140000
DTEND;TZID=Asia/Seoul:20250725T160000
DTSTAMP:20260422T074007
CREATED:20250628T123019Z
LAST-MODIFIED:20250721T002532Z
UID:11218-1753452000-1753459200@www.ibs.re.kr
SUMMARY:Effective Markovian dynamics method of solving non-Markovian dynamics of stochastic gene expression - Dongju Lim
DESCRIPTION:In this talk\, we discuss the paper “Effective Markovian dynamics method of solving non-Markovian dynamics of stochastic gene expression” by Youming Li and Chen Jia\, Physical Review Letters\, to appear. \nAbstract \nExperiments have shown that over 10% of proteins are degraded non-exponentially. Gene expression models for non-exponentially degraded proteins are notoriously difficult to solve since the underlying stochastic dynamics is non-Markovian. Here we develop an effective Markovian dynamics (EMD) method which converts a large class of non-Markovian models into effective Markovian ones so that they have the same mRNA and protein distributions at any fixed time. Using the EMD approach\, we analytically solve some classical gene expression models with non-exponential or delayed protein decay\, whose exact distributions are previously unknown and fail to be obtained using conventional queueing theory. Our theory successfully explains why non-exponentially degraded proteins on average have smaller mRNA-protein correlation than exponentially degraded proteins\, and it predicts that bimodality is significantly enhanced in the presence of delayed protein degradation.
URL:https://www.ibs.re.kr/bimag/event/action-functional-as-an-early-warning-indicator-in-the-space-of-probability-measures-via-schrodinger-bridge-dongju-lim/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250718T140000
DTEND;TZID=Asia/Seoul:20250718T160000
DTSTAMP:20260422T074007
CREATED:20250701T022224Z
LAST-MODIFIED:20250701T022224Z
UID:11231-1752847200-1752854400@www.ibs.re.kr
SUMMARY:scGPT: toward building a foundation model for single-cell multi-omics using generative AI - Hyun Kim
DESCRIPTION:In this talk\, we discuss the paper “scGPT: toward building a foundation model for single-cell multi-omics using generative AI” by Haotian Cui\, et.al. Nature Methods\, 2024. \nAbstract \nGenerative pretrained models have achieved remarkable success in various domains such as language and computer vision. Specifically\, the combination of large-scale diverse datasets and pretrained transformers has emerged as a promising approach for developing foundation models. Drawing parallels between language and cellular biology (in which texts comprise words; similarly\, cells are defined by genes)\, our study probes the applicability of foundation models to advance cellular biology and genetic research. Using burgeoning single-cell sequencing data\, we have constructed a foundation model for single-cell biology\, scGPT\, based on a generative pretrained transformer across a repository of over 33 million cells. Our findings illustrate that scGPT effectively distills critical biological insights concerning genes and cells. Through further adaptation of transfer learning\, scGPT can be optimized to achieve superior performance across diverse downstream applications. This includes tasks such as cell type annotation\, multi-batch integration\, multi-omic integration\, perturbation response prediction and gene network inference.
URL:https://www.ibs.re.kr/bimag/event/scgpt-toward-building-a-foundation-model-for-single-cell-multi-omics-using-generative-ai-hyun-kim/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250711T140000
DTEND;TZID=Asia/Seoul:20250711T160000
DTSTAMP:20260422T074007
CREATED:20250628T122808Z
LAST-MODIFIED:20250628T122808Z
UID:11216-1752242400-1752249600@www.ibs.re.kr
SUMMARY:Optimal transport for generating transition states in chemical reactions - Gyuyoung Hwang
DESCRIPTION:In this talk\, we discuss the paper “Optimal transport for generating transition states in chemical reactions” by C. Duan et.al.\, Nat. Machine. Intelligence\, 2025. \nAbstract \nTransition states (TSs) are transient structures that are key to understanding reaction mechanisms and designing catalysts but challenging to capture in experiments. Many optimization algorithms have been developed to search for TSs computationally. Yet\, the cost of these algorithms driven by quantum chemistry methods (usually density functional theory) is still high\, posing challenges for their applications in building large reaction networks for reaction exploration. Here we developed React-OT\, an optimal transport approach for generating unique TS structures from reactants and products. React-OT generates highly accurate TS structures with a median structural root mean square deviation of 0.053 Å and median barrier height error of 1.06 kcal mol−1 requiring only 0.4 s per reaction. The root mean square deviation and barrier height error are further improved by roughly 25% through pretraining React-OT on a large reaction dataset obtained with a lower level of theory\, GFN2-xTB. We envision that the remarkable accuracy and rapid inference of React-OT will be highly useful when integrated with the current high-throughput TS search workflow. This integration will facilitate the exploration of chemical reactions with unknown mechanisms.
URL:https://www.ibs.re.kr/bimag/event/optimal-transport-for-generating-transition-states-in-chemical-reactions-gyuyoung-hwang/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250704T140000
DTEND;TZID=Asia/Seoul:20250704T160000
DTSTAMP:20260422T074007
CREATED:20250526T004910Z
LAST-MODIFIED:20250609T001902Z
UID:11146-1751637600-1751644800@www.ibs.re.kr
SUMMARY:Machine learning methods trained on simple models can predict critical transitions in complex natural systems - Shingo Gibo
DESCRIPTION:In this talk\, we discuss the paper “Machine learning methods trained on simple models can predict critical transitions in complex natural systems” by  Smita Deb\, Sahil Sidheekh\, Christopher F. Clements\, Narayanan C. Krishnan\, and Partha S. Dutta\, in Royal Society Open Science\, (2022). \nAbstract:  \nForecasting sudden changes in complex systems is a critical but challenging task\, with previously developed methods varying widely in their reliability. Here we develop a novel detection method\, using simple theoretical models to train a deep neural network to detect critical transitions—the Early Warning Signal Network (EWSNet). We then demonstrate that this network\, trained on simulated data\, can reliably predict observed real-world transitions in systems ranging from rapid climatic change to the collapse of ecological populations. Importantly\, our model appears to capture latent properties in time series missed by previous warning signals approaches\, allowing us to not only detect if a transition is approaching\, but critically whether the collapse will be catastrophic or non-catastrophic. These novel properties mean EWSNet has the potential to serve as an indicator of transitions across a broad spectrum of complex systems\, without requiring information on the structure of the system being monitored. Our work highlights the practicality of deep learning for addressing further questions pertaining to ecosystem collapse and has much broader management implications.
URL:https://www.ibs.re.kr/bimag/event/machine-learning-methods-trained-on-simple-models-can-predict-critical-transitions-in-complex-natural-systems-shingo-gibo/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250627T140000
DTEND;TZID=Asia/Seoul:20250627T160000
DTSTAMP:20260422T074007
CREATED:20250426T143642Z
LAST-MODIFIED:20250609T001825Z
UID:11067-1751032800-1751040000@www.ibs.re.kr
SUMMARY:Data splitting to avoid information leakage with DataSAIL - Myna Lim
DESCRIPTION:In this talk\, we discuss the paper\, “Data splitting to avoid information leakage with DataSAIL” by Roman Joeres\, et al.\, Nature Communications\, 2025. \nAbstract \nInformation leakage is an increasingly important topic in machine learning research for biomedical applications. When information leakage happens during a model’s training\, it risks memorizing the training data instead of learning generalizable properties. This can lead to inflated performance metrics that do not reflect the actual performance at inference time. We present DataSAIL\, a versatile Python package to facilitate leakage-reduced data splitting to enable realistic evaluation of machine learning models for biological data that are intended to be applied in out-of-distribution scenarios. DataSAIL is based on formulating the problem to find leakage-reduced data splits as a combinatorial optimization problem. We prove that this problem is NP-hard and provide a scalable heuristic based on clustering and integer linear programming. Finally\, we empirically demonstrate DataSAIL’s impact on evaluating biomedical machine learning models.
URL:https://www.ibs.re.kr/bimag/event/data-splitting-to-avoid-information-leakage-with-datasail-myna-lim/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250620T110000
DTEND;TZID=Asia/Seoul:20250620T123000
DTSTAMP:20260422T074007
CREATED:20250426T143500Z
LAST-MODIFIED:20250617T001232Z
UID:11064-1750417200-1750422600@www.ibs.re.kr
SUMMARY:Large language models for scientific discovery in molecular property prediction - Aqsa Awan
DESCRIPTION:In this talk\, we discuss the paper “Large language models for scientific discovery in molecular property prediction” by Yizhen Zheng et.al.\, nature machine intelligence\, 2025. \nAbstract \nLarge language models (LLMs) are a form of artificial intelligence system encapsulating vast knowledge in the form of natural language. These systems are adept at numerous complex tasks including creative writing\, storytelling\, translation\, question-answering\, summarization and computer code generation. Although LLMs have seen initial applications in natural sciences\, their potential for driving scientific discovery remains largely unexplored. In this work\, we introduce LLM4SD\, a framework designed to harness LLMs for driving scientific discovery in molecular property prediction by synthesizing knowledge from literature and inferring knowledge from scientific data. LLMs synthesize knowledge by extracting established information from scientific literature\, such as molecular weight being key to predicting solubility. For inference\, LLMs identify patterns in molecular data\, particularly in Simplified Molecular Input Line Entry System-encoded structures\, such as halogen-containing molecules being more likely to cross the blood–brain barrier. This information is presented as interpretable knowledge\, enabling the transformation of molecules into feature vectors. By using these features with interpretable models such as random forest\, LLM4SD can outperform the current state of the art across a range of benchmark tasks for predicting molecular properties. We foresee it providing interpretable and potentially new insights\, aiding scientific discovery in molecular property prediction.
URL:https://www.ibs.re.kr/bimag/event/large-language-models-for-scientific-discovery-in-molecular-property-prediction-aqsa-awan/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250613T093000
DTEND;TZID=Asia/Seoul:20250613T110000
DTSTAMP:20260422T074007
CREATED:20250609T002038Z
LAST-MODIFIED:20250609T033628Z
UID:11164-1749807000-1749812400@www.ibs.re.kr
SUMMARY:Deep learning for universal linear embeddings of nonlinear dynamics - Hyukpyo Hong
DESCRIPTION:In this talk\, we discuss the paper “Deep learning for universal linear embeddings of nonlinear dynamics” by B. Lusch\, J. N. Kutz\, and S. Brunton\, Nat. Comm. 2018. \nAbstract  \nIdentifying coordinate transformations that make strongly nonlinear dynamics approximately linear has the potential to enable nonlinear prediction\, estimation\, and control using linear theory. The Koopman operator is a leading data-driven embedding\, and its eigenfunctions provide intrinsic coordinates that globally linearize the dynamics. However\, identifying and representing these eigenfunctions has proven challenging. This work leverages deep learning to discover representations of Koopman eigenfunctions from data. Our network is parsimonious and interpretable by construction\, embedding the dynamics on a low-dimensional manifold. We identify nonlinear coordinates on which the dynamics are globally linear using a modified auto-encoder. We also generalize Koopman representations to include a ubiquitous class of systems with continuous spectra. Our framework parametrizes the continuous frequency using an auxiliary network\, enabling a compact and efficient embedding\, while connecting our models to decades of asymptotics. Thus\, we benefit from the power of deep learning\, while retaining the physical interpretability of Koopman embeddings.
URL:https://www.ibs.re.kr/bimag/event/hyukpyo-hong/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250530T140000
DTEND;TZID=Asia/Seoul:20250530T160000
DTSTAMP:20260422T074007
CREATED:20250426T143239Z
LAST-MODIFIED:20250528T035910Z
UID:11061-1748613600-1748620800@www.ibs.re.kr
SUMMARY:Direct Estimation of Parameters in ODE Models Using WENDy - Kangmin Lee
DESCRIPTION:In this talk\, we discuss the paper “Direct Estimation of Parameters in ODE Models Using WENDy: Weak-Form Estimation of Nonlinear Dynamics” by David M. Bortz\, Daniel A. Messenger\, and Vanja Dukic\, Bulletin of Mathematical Biology\, 2023. \nAbstract \nWe introduce the Weak-form Estimation of Nonlinear Dynamics (WENDy) method for estimating model parameters for non-linear systems of ODEs. Without relying on any numerical differential equation solvers\, WENDy computes accurate estimates and is robust to large (biologically relevant) levels of measurement noise. For low dimensional systems with modest amounts of data\, WENDy is competitive with conventional forward solver-based nonlinear least squares methods in terms of speed and accuracy. For both higher dimensional systems and stiff systems\, WENDy is typically both faster (often by orders of magnitude) and more accurate than forward solver-based approaches. The core mathematical idea involves an efficient conversion of the strong form representation of a model to its weak form\, and then solving a regression problem to perform parameter inference. The core statistical idea rests on the Errors-In-Variables framework\, which necessitates the use of the iteratively reweighted least squares algorithm. Further improvements are obtained by using orthonormal test functions\, created from a set of C∞ bump functions of varying support sizes.We demonstrate the high robustness and computational efficiency by applying WENDy to estimate parameters in some common models from population biology\, neuroscience\, and biochemistry\, including logistic growth\, Lotka-Volterra\, FitzHugh-Nagumo\, Hindmarsh-Rose\, and a Protein Transduction Benchmark model. Software and code for reproducing the examples is available at https://github.com/MathBioCU/WENDy.
URL:https://www.ibs.re.kr/bimag/event/quantifying-and-correcting-bias-in-transcriptional-parameter-inference-from-single-cell-data-kangmin-lee/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250509T140000
DTEND;TZID=Asia/Seoul:20250509T160000
DTSTAMP:20260422T074007
CREATED:20250426T142850Z
LAST-MODIFIED:20250507T002814Z
UID:11058-1746799200-1746806400@www.ibs.re.kr
SUMMARY:Network inference from short\, noisy\, low time-resolution\, partial measurements: Application to C. elegans neuronal calcium dynamics - Olive Cawiding
DESCRIPTION:In this talk\, we discuss the paper “Network inference from short\, noisy\, low time-resolution\, partial measurements: Application to C. elegans neuronal calcium dynamics” by Amitava Banerjee\, Sarthak Chandra\, and Edward Ott\, PNAS\, 2023. \nAbstract \nNetwork link inference from measured time series data of the behavior of dynamically interacting network nodes is an important problem with wide-ranging applications\, e.g.\, estimating synaptic connectivity among neurons from measurements of their calcium fluorescence. Network inference methods typically begin by using the measured time series to assign to any given ordered pair of nodes a numerical score reflecting the likelihood of a directed link between those two nodes. In typical cases\, the measured time series data may be subject to limitations\, including limited duration\, low sampling rate\, observational noise\, and partial nodal state measurement. However\, it is unknown how the performance of link inference techniques on such datasets depends on these experimental limitations of data acquisition. Here\, we utilize both synthetic data generated from coupled chaotic systems as well as experimental data obtained from Caenorhabditis elegans neural activity to systematically assess the influence of data limitations on the character of scores reflecting the likelihood of a directed link between a given node pair. We do this for three network inference techniques: Granger causality\, transfer entropy\, and\, a machine learning-based method. Furthermore\, we assess the ability of appropriate surrogate data to determine statistical confidence levels associated with the results of link-inference techniques.
URL:https://www.ibs.re.kr/bimag/event/chaos-is-not-rare-in-natural-ecosystems-olive-cawiding/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250502T140000
DTEND;TZID=Asia/Seoul:20250502T160000
DTSTAMP:20260422T074007
CREATED:20250330T073307Z
LAST-MODIFIED:20250424T070416Z
UID:10929-1746194400-1746201600@www.ibs.re.kr
SUMMARY:Boolean modelling as a logic-based dynamic approach in systems medicine - Kevin Spinicci
DESCRIPTION:In this talk\, we discuss the paper “Boolean modelling as a logic-based dynamic approach in systems medicine” by Ahmed Abdelmonem Hemedan et al.\, Computational and Structural biotechnology journal (2022). \nAbstract  \nMolecular mechanisms of health and disease are often represented as systems biology diagrams\, and the coverage of such representation constantly increases. These static diagrams can be transformed into dynamic models\, allowing for in silico simulations and predictions. Boolean modelling is an approach based on an abstract representation of the system. It emphasises the qualitative modelling of biological systems in which each biomolecule can take two possible values: zero for absent or inactive\, one for present or active. Because of this approximation\, Boolean modelling is applicable to large diagrams\, allowing to capture their dynamic properties. We review Boolean models of disease mechanisms and compare a range of methods and tools used for analysis processes. We explain the methodology of Boolean analysis focusing on its application in disease modelling. Finally\, we discuss its practical application in analysing signal transduction and gene regulatory pathways in health and disease.
URL:https://www.ibs.re.kr/bimag/event/boolean-modelling-as-a-logic-based-dynamic-approach-in-systems-medicine-kevin-spinicci/
LOCATION:Daejeon
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250418T140000
DTEND;TZID=Asia/Seoul:20250418T160000
DTSTAMP:20260422T074007
CREATED:20250327T010619Z
LAST-MODIFIED:20250327T010619Z
UID:10923-1744984800-1744992000@www.ibs.re.kr
SUMMARY:Identifying key drivers in a stochastic dynamical system through estimation of transfer entropy between univariate and multivariate time series - Yun Min Song
DESCRIPTION:In this talk\, we discuss the paper “Identifying key drivers in a stochastic dynamical system through estimation of transfer entropy between univariate and multivariate time series” by Julian Lee\, Physical Review E\, 2025. \nAbstract  \nTransfer entropy (TE) is a widely used tool for quantifying causal relationships in stochastic dynamical systems. Traditionally\, TE and its conditional variants are applied pairwise between dynamic variables to infer these relationships. However\, identifying key drivers in such systems requires a measure of the causal influence exerted by each component on the entire system. I propose using outgoing transfer entropy (OutTE)\, the transfer entropy from a given variable to the collection of remaining variables\, to quantify the causal influence of the variable on the rest of the system. Conversely\, the incoming transfer entropy (InTE) is also defined to quantify the causal influence received by a component from the rest of the system. Since OutTE and InTE involve transfer entropy between univariate and multivariate time series\, naive estimation methods can result in significant errors\, especially when the number of variables is large relative to the number of samples. To address this\, I introduce a novel estimation scheme that computes outgoing and incoming TE only between significantly interacting partners. The feasibility and effectiveness of this approach are demonstrated using synthetic data and real oral microbiota data. The method successfully identifies the bacterial species known to be key players in the bacterial community\, highlighting its potential for uncovering causal drivers in complex systems.
URL:https://www.ibs.re.kr/bimag/event/identifying-key-drivers-in-a-stochastic-dynamical-system-through-estimation-of-transfer-entropy-between-univariate-and-multivariate-time-series-yun-min-song/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250411T140000
DTEND;TZID=Asia/Seoul:20250411T160000
DTSTAMP:20260422T074007
CREATED:20250327T010416Z
LAST-MODIFIED:20250327T010416Z
UID:10921-1744380000-1744387200@www.ibs.re.kr
SUMMARY:Entrainment and multi-stability of the p53 oscillator in human cells - Eui Min Jeong
DESCRIPTION:In this talk\, we discuss the paper\, “Entrainment and multi-stability of the p53 oscillator in human cells” by Alba Jiménez et al.\, Cell Systems\, 2024. \nAbstract  \nThe tumor suppressor p53 responds to cellular stress and activates transcription programs critical for regulating cell fate. DNA damage triggers oscillations in p53 levels with a robust period. Guided by the theory of synchronization and entrainment\, we developed a mathematical model and experimental system to test the ability of the p53 oscillator to entrain to external drug pulses of various periods and strengths. We found that the p53 oscillator can be locked and entrained to a wide range of entrainment modes. External periods far from p53’s natural oscillations increased the heterogeneity between individual cells whereas stronger inputs reduced it. Single-cell measurements allowed deriving the phase response curves (PRCs) and multiple Arnold tongues of p53. In addition\, multi-stability and non-linear behaviors were mathematically predicted and experimentally detected\, including mode hopping\, period doubling\, and chaos. Our work revealed critical dynamical properties of the p53 oscillator and provided insights into understanding and controlling it. A record of this paper’s transparent peer review process is included in the supplemental information.
URL:https://www.ibs.re.kr/bimag/event/entrainment-and-multi-stability-of-the-p53-oscillator-in-human-cells-eui-min-jeong/
LOCATION:B232 Seminar Room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250404T140000
DTEND;TZID=Asia/Seoul:20250404T160000
DTSTAMP:20260422T074007
CREATED:20250326T091007Z
LAST-MODIFIED:20250330T013324Z
UID:10919-1743775200-1743782400@www.ibs.re.kr
SUMMARY:Accurate predictions on small data with a tabular foundation model - Dongju Lim
DESCRIPTION:In this talk\, we discuss the paper “Accurate predictions on small data with a tabular foundation model” by Noah Hollmann et al.\, Nature (2025). \nAbstract \nTabular data\, spreadsheets organized in rows and columns\, are ubiquitous across scientific fields\, from biomedicine to particle physics to economics and climate science1\,2. The fundamental prediction task of filling in missing values of a label column based on the rest of the columns is essential for various applications as diverse as biomedical risk models\, drug discovery and materials science. Although deep learning has revolutionized learning from raw data and led to numerous high-profile success stories3\,4\,5\, gradient-boosted decision trees6\,7\,8\,9 have dominated tabular data for the past 20 years. Here we present the Tabular Prior-data Fitted Network (TabPFN)\, a tabular foundation model that outperforms all previous methods on datasets with up to 10\,000 samples by a wide margin\, using substantially less training time. In 2.8 s\, TabPFN outperforms an ensemble of the strongest baselines tuned for 4 h in a classification setting. As a generative transformer-based foundation model\, this model also allows fine-tuning\, data generation\, density estimation and learning reusable embeddings. TabPFN is a learning algorithm that is itself learned across millions of synthetic datasets\, demonstrating the power of this approach for algorithm development. By improving modelling abilities across diverse fields\, TabPFN has the potential to accelerate scientific discovery and enhance important decision-making in various domains.
URL:https://www.ibs.re.kr/bimag/event/a-differentiable-gillespie-algorithm-for-simulating-chemical-kinetics-parameter-estimation-and-designing-synthetic-biological-circuits-dongju-lim/
LOCATION:Daejeon
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
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BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250328T140000
DTEND;TZID=Asia/Seoul:20250328T160000
DTSTAMP:20260422T074007
CREATED:20250302T133447Z
LAST-MODIFIED:20250327T010923Z
UID:10853-1743170400-1743177600@www.ibs.re.kr
SUMMARY:Frequency-Dependent Covariance Reveals Critical Spatiotemporal Patterns of Synchronized Activity in the Human Brain - Hyun Kim
DESCRIPTION:In this talk\, we discuss the paper “Frequency-Dependent Covariance Reveals Critical Spatiotemporal Patterns of Synchronized Activity in the Human Brain” by Rubén Calvo et al.\, Physical Review Letters 2024\, at the Journal Club. \nAbstract \nRecent analyses\, leveraging advanced theoretical techniques and high-quality data from thousands of simultaneously recorded neurons across regions in the brain\, compellingly support the hypothesis that neural dynamics operate near the edge of instability. However\, these and related analyses often fail to capture the intricate temporal structure of brain activity\, as they primarily rely on time-integrated measurements across neurons. Here\, we present a novel framework designed to explore signatures of criticality across diverse frequency bands and construct a much more comprehensive description of brain activity. Furthermore\, we introduce a method for projecting brain activity onto a basis of spatiotemporal patterns\, facilitating time-dependent dimensionality reduction. Applying this framework to a magnetoencephalography dataset\, we observe significant differences in criticality signatures\, effective dimensionality\, and spatiotemporal activity patterns between healthy subjects and individuals with Parkinson’s disease\, highlighting its potential impact.
URL:https://www.ibs.re.kr/bimag/event/journal-club-hyun-kim/
LOCATION:Daejeon
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
END:VCALENDAR