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1. Performance of Response Based One Shot Controls Handling Missing Phasor Measurements

   https://doi.org/10.1109/PESGM41954.2020.9281396  

   Dahal, Niraj; Rovnyak, Steven M. (August 2020, 2020 IEEE Power & Energy Society General Meeting (PESGM))

   null (Ed.)

   With the advent of real-time PMU data acquisition technology, the possibility of solutions to several instability problems in power system has increased. However, PMUs may undergo different data quality issues like recording bad data or missing data. Some paper mentions about 5-10% of missing samples in some historical PMU's dataset. This paper assumes 0-10% of missing phasor samples by randomly deleting measurements and explores imputation methods of handling missing data in real time. The simulation is carried out in a DT-based stability prediction and one-shot control scheme of WECC's 176-bus model. Several control performances are evaluated to decide a useful method of missing data recovery for the response based one shot control scheme. A PMU data quality issue is not limited to missing samples only but also interference with noises. Later part of this paper performs simulation considering noisy phasor measurements. A 45 dB of Gaussian distributed noise is deliberately added to phasor samples and simulation is performed with different DT indices and thresholds for real time stability prediction and control actuation. 

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2. VIGAN: Missing view imputation with generative adversarial networks

   https://doi.org/10.1109/BigData.2017.8257992  

   Shang, Chao; Palmer, Aaron; Sun, Jiangwen; Chen, Ko-Shin; Lu, Jin; Bi, Jinbo (December 2017, 2017 IEEE International Conference on Big Data (Big Data))

   In an era when big data are becoming the norm, there is less concern with the quantity but more with the quality and completeness of the data. In many disciplines, data are collected from heterogeneous sources, resulting in multi-view or multi-modal datasets. The missing data problem has been challenging to address in multi-view data analysis. Especially, when certain samples miss an entire view of data, it creates the missing view problem. Classic multiple imputations or matrix completion methods are hardly effective here when no information can be based on in the specific view to impute data for such samples. The commonly-used simple method of removing samples with a missing view can dramatically reduce sample size, thus diminishing the statistical power of a subsequent analysis. In this paper, we propose a novel approach for view imputation via generative adversarial networks (GANs), which we name by VIGAN. This approach first treats each view as a separate domain and identifies domain-to-domain mappings via a GAN using randomly-sampled data from each view, and then employs a multi-modal denoising autoencoder (DAE) to reconstruct the missing view from the GAN outputs based on paired data across the views. Then, by optimizing the GAN and DAE jointly, our model enables the knowledge integration for domain mappings and view correspondences to effectively recover the missing view. Empirical results on benchmark datasets validate the VIGAN approach by comparing against the state of the art. The evaluation of VIGAN in a genetic study of substance use disorders further proves the effectiveness and usability of this approach in life science. 

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3. Categorical Databases for Mathematical Formalization of AC Optimal Power Flow

   https://doi.org/10.1109/TPEC56611.2023.10078526  

   Barati, Masoud (February 2023, IEEE)

   It has been decades since category theory was applied to databases. In spite of their mathematical elegance, categorical models have traditionally had difficulty representing factual data, such as integers or strings. This paper proposes a categorical dataset for power system computational models, which is used for AC Optimal Power Flows (ACOPF). In addition, categorical databases incorporate factual data using multi-sorted algebraic theories (also known as Lawvere theories) based on the set-valued functor model. In the advanced metering infrastructure of power systems, this approach is capable of handling missing information efficiently. This methodology enables constraints and queries to employ operations on data, such as multiplicative and comparative processes, thereby facilitating the integration between conventional databases and programming languages like Julia and Python’s Pypower. The demonstration illustrates how all elements of the model, including schemas, instances, and functors, can modify the schema in ACOPF instances. 

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4. Inpainting Hydrodynamical Maps with Deep Learning

   https://doi.org/10.3847/1538-4357/ac9f14  

   Mohammad, Faizan G.; Villaescusa-Navarro, Francisco; Genel, Shy; Anglés-Alcázar, Daniel; Vogelsberger, Mark (December 2022, The Astrophysical Journal)

   Abstract From 1000 hydrodynamic simulations of the CAMELS project, each with a different value of the cosmological and astrophysical parameters, we generate 15,000 gas temperature maps. We use a state-of-the-art deep convolutional neural network to recover missing data from those maps. We mimic the missing data by applying regular and irregular binary masks that cover either 15% or 30% of the area. We quantify the reliability of our results using two summary statistics: (1) the distance between the probability density functions, estimated using the Kolmogorov–Smirnov (K-S) test, and (2) the 2D power spectrum. We find an excellent agreement between the model prediction and the unmasked maps when using the power spectrum: better than 1% fork< 20hMpc⁻¹for any irregular mask. For regular masks, we observe a systematic offset of ∼5% when covering 15% of the maps, while the results become unreliable when 30% of the data is missing. The observed K-S testp-values favor the null hypothesis that the reconstructed and the ground-truth maps are drawn from the same underlying distribution when irregular masks are used. For regular-shaped masks, on the other hand, we find a strong evidence that the two distributions do not match each other. Finally, we use the model, trained on gas temperature maps, to inpaint maps from fields not used during model training. We find that, visually, our model is able to reconstruct the missing pixels from the maps of those fields with great accuracy, although its performance using summary statistics depends strongly on the considered field. 

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5. Stochastic logic in biased coupled photonic probabilistic bits

   https://doi.org/10.1038/s42005-025-01953-1  

   Horodynski, Michael; Roques-Carmes, Charles; Salamin, Yannick; Choi, Seou; Sloan, Jamison; Luo, Di; Soljačić, Marin (January 2025, Communications Physics)

   Abstract Optical computing often employs tailor-made hardware to implement specific algorithms, trading generality for improved performance in key aspects like speed and power efficiency. An important computing approach that is still missing its corresponding optical hardware is probabilistic computing, used e.g. for solving difficult combinatorial optimization problems. In this study, we propose an experimentally viable photonic approach to solve arbitrary probabilistic computing problems. Our method relies on the insight that coherent Ising machines composed of coupled and biased optical parametric oscillators can emulate stochastic logic. We demonstrate the feasibility of our approach by using numerical simulations equivalent to the full density matrix formulation of coupled optical parametric oscillators. 

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