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X-WR-CALNAME:Biomedical Mathematics Group
X-ORIGINAL-URL:https://www.ibs.re.kr/bimag
X-WR-CALDESC:Events for Biomedical Mathematics Group
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TZID:Asia/Seoul
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TZOFFSETFROM:+0900
TZOFFSETTO:+0900
TZNAME:KST
DTSTART:20200101T000000
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BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20211215T143000
DTEND;TZID=Asia/Seoul:20211215T160000
DTSTAMP:20260427T051552
CREATED:20211214T190000Z
LAST-MODIFIED:20211214T070933Z
UID:5299-1639578600-1639584000@www.ibs.re.kr
SUMMARY:Stiff-PINN: Physics-Informed Neural Network for Stiff Chemical Kinetics
DESCRIPTION:We will discuss about “Stiff-PINN: Physics-Informed Neural Network for Stiff Chemical Kinetics”\, Ji et al.\, The Journal of Physical Chemistry A\, 2020 \nThe recently developed physics-informed neural network (PINN) has achieved success in many science and engineering disciplines by encoding physics laws into the loss functions of the neural network such that the network not only conforms to the measurements and initial and boundary conditions but also satisfies the governing equations. This work first investigates the performance of the PINN in solving stiff chemical kinetic problems with governing equations of stiff ordinary differential equations (ODEs). The results elucidate the challenges of utilizing the PINN in stiff ODE systems. Consequently\, we employ quasi-steady-state assumption (QSSA) to reduce the stiffness of the ODE systems\, and the PINN then can be successfully applied to the converted non-/mild-stiff systems. Therefore\, the results suggest that stiffness could be the major reason for the failure of the regular PINN in the studied stiff chemical kinetic systems. The developed stiff-PINN approach that utilizes QSSA to enable the PINN to solve stiff chemical kinetics shall open the possibility of applying the PINN to various reaction-diffusion systems involving stiff dynamics.
URL:https://www.ibs.re.kr/bimag/event/2021-12-15/
LOCATION:B378 Seminar room\, IBS\, 55 Expo-ro Yuseong-gu\, 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:20211224T130000
DTEND;TZID=Asia/Seoul:20211224T140000
DTSTAMP:20260427T051552
CREATED:20211223T190000Z
LAST-MODIFIED:20211221T043551Z
UID:5302-1640350800-1640354400@www.ibs.re.kr
SUMMARY:Information Integration and Energy Expenditure in Gene Regulation
DESCRIPTION:We will discuss about “Information Integration and Energy Expenditure in Gene Regulation”\, Estrada et al.\, Cell\, 2016 \nAbstract: The quantitative concepts used to reason about gene regulation largely derive from bacterial studies. We show that this bacterial paradigm cannot explain the sharp expression of a canonical developmental gene in response to a regulating transcription factor (TF). In the absence of energy expenditure\, with regulatory DNA at thermodynamic equilibrium\, information integration across multiple TF binding sites can generate the required sharpness\, but with strong constraints on the resultant “higher-order cooperativities.” Even with such integration\, there is a “Hopfield barrier” to sharpness; for n TF binding sites\, this barrier is represented by the Hill function with the Hill coefficient n. If\, however\, energy is expended to maintain regulatory DNA away from thermodynamic equilibrium\, as in kinetic proofreading\, this barrier can be breached and greater sharpness achieved. Our approach is grounded in fundamental physics\, leads to testable experimental predictions\, and suggests how a quantitative paradigm for eukaryotic gene regulation can be formulated.
URL:https://www.ibs.re.kr/bimag/event/2021-12-24/
LOCATION:B378 Seminar room\, IBS\, 55 Expo-ro Yuseong-gu\, 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:20211231T130000
DTEND;TZID=Asia/Seoul:20211231T140000
DTSTAMP:20260427T051552
CREATED:20211230T190000Z
LAST-MODIFIED:20211227T004211Z
UID:5306-1640955600-1640959200@www.ibs.re.kr
SUMMARY:The Generalized Multiset Sampler
DESCRIPTION:We will discuss about “The Generalized Multiset Sampler”\, Kim and MacEachern\, The Journal of Computation and Graphical Statistics\, 2021 \nAbstract: The multiset sampler\, an MCMC algorithm recently proposed by Leman and coauthors\, is an easy-to-implement algorithm which is especially well-suited to drawing samples from a multimodal distribution. We generalize the algorithm by redefining the multiset sampler with an explicit link between target distribution and sampling distribution. The generalized formulation replaces the multiset with a K-tuple\, which allows us to use the algorithm on unbounded parameter spaces\, improves estimation\, and sets up further extensions to adaptive MCMC techniques. Theoretical properties of the algorithm are provided and guidance is given on its implementation. Examples\, both simulated and real\, confirm that the generalized multiset sampler provides a simple\, general and effective approach to sampling from multimodal distributions. Supplementary materials for this article are available online.
URL:https://www.ibs.re.kr/bimag/event/2021-12-31/
LOCATION:B378 Seminar room\, IBS\, 55 Expo-ro Yuseong-gu\, Daejeon\, 34126\, Korea\, Republic of
CATEGORIES:Journal Club
ORGANIZER;CN="Jae Kyoung Kim":MAILTO:jaekkim@kaist.ac.kr
END:VEVENT
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