= Noise Subtraction subgroup =

== Pre-meeting ==

 * Date/Time: Tuesday, November 5th, 2024, 1600-1800 JST (0700-0900 UTC)
 * Connection Info.: Zoom1 
 * Agenda
   * '''Brief''' Overview of Noise Subtraction Activities
      Application to GW experiments/analysis
       * What can be accomplished? How effective is it in improving sensitivity/analysis etc.?
         * Example of NonSENS subtraction at H1, November 2nd, 2024: https://ldas-jobs.ligo-wa.caltech.edu/~detchar/summary/day/20241102/cal/nonsens/#gallery-9
     * Activities at KAGRA (Who?, Project name?, '''**Features?(What can and what can't be done?)**''', Current status?, Future plan?)
      1. Algorithm development
       * ARIMA(AR Integrated MA) : Fujimoto (OCU)
         * [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=12974|JGW-G2112974-v3]]
       * Liner ICA (Independent Component Analysis) : Yokoyama & Kume (RESCEU), Itoh & Kobayashi (OMU)
         * Ref.: https://doi.org/10.1093/ptep/ptaa056
         * .. 
       * Non-liner ICA  :  Yokoyama & Kume (RESCEU)
         * [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=15951|JGW-G2415951]]
         * [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=13723|JGW-G2213723]]
       * !DeepClean (CNN) : Yi, Chou, Yeh (NYCU, NTHU)
         * Ref.: https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.2.033066
         * Low-Latency and Offline Deployment
         * KAGRA F2F　Summer 2024 Slides: https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=15977
         * ..
       * LSTM : Itoh & Takatani (OMU)
         * JPS [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=15456|JGW-G2315456-v6]]
         * Master Thesis [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=15615|JGW-P2415615-v3]]
       * PINN (Physics-informed neural network) : Dan Chen & Sakemi
         * JPS 2023 Autumn [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=15075|JGW-G2315075]]
         * JPS 2024 Spring [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=15603|JGW-G2415603]]

      2. Target noises & Witness channels study
           * AC power 60 Hz and its harmonics
           * Acoustic noise (PSL, IFI, OMC, ...)
           * Other Dofs (CARM, MICH, PRCL)
           * OMC length
           * ASC
           * Beam jitter (IMMT1 trans QPD)
           * VIS
           * Violin mode (w/o Witness channels)
           * CAL lines
           * issue: Safe channel

      3. Computers and Pipelines
           * GPU for offline !DeepClean @ Taiwan
           * GPU for online !DeepClean @ Kamioka
           * Kashiwa KMST
           * RESCEU

    * Other efforts within LV(K)
       * NonSENS (NON-Stationary Estimation of Noise Subtraction)
          * Derivation and description of algorithm: https://dcc.ligo.org/LIGO-T1800525
            * Estimates the optimal noise subtraction based on witnesses for the noise and witnesses for modulation of the noise coupling
            * Witness channel can be individual channels (linear subtraction), or product of two channels (bilinear subtraction) 
          * Codebase: https://git.ligo.org/gabriele-vajente/nonsens
          * Running online at LHO/LLO
            * Front-end implementations:
              * LHO https://git.ligo.org/noisecleaning_o4/frontend-nonsens/lho-online-cleaning 
              * LLO https://git.ligo.org/noisecleaning_o4/frontend-nonsens/llo-online-cleaning 
            * The output channels are available in the control rooms, for use with commissioning, and are the same channels that analysis pipelines will use.
       * ...

 * Scope '''of the Group''' to be established
   * Organization?
    * Chia-Jui Chou from Natl. Yang Ming Chiao Tung U. will lead the group as the chief.
    * Will the group encompass all noise subtraction-related activities at KAGRA? (ICA+!DeepClean+...)
    * Will the group focus specifically on areas that contribute to the commissioning timeline, i.e., ''low-'' or ''middle-latency''?
    * or...
  * Roles/Goals for each phase
    * During the commissioning period prior to participating in O4b observation
    * During the O4b observation
       * Q: Will the cleaned h(t) produced by this team be used as an official deliverable and released to the public?!
    * For future phases O5/O6
  * How collaborate with on-site commissioners/IFO experts?
     * e.g., 
       * Commissioners may request specific noise subtraction, such as subtracting noise in ''channel-A'' using ''auxiliary channel-B''?
       * Commissioners may manage a safe channel list?
       * ...
     * What considerations should guide us as we progress? How should we work with the team?

 * NOTE: The following terms mean different things. Please use them correctly when discussing:
   * Safe channel, Witness channel, Auxiliary channel, ...
   * Online(front-end), Low-latency, Middle-latency, High-latency, (offline), ...