TopicBank: Collection of coherent topics using multiple model training with their further use for topic model validation

2021 ◽  
Vol 135 ◽  
pp. 101921
Author(s):  
Vasiliy Alekseev ◽  
Evgeny Egorov ◽  
Konstantin Vorontsov ◽  
Alexey Goncharov ◽  
Kaidar Nurumov ◽  
...  
Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3162
Author(s):  
Nikolaos Kolokas ◽  
Dimosthenis Ioannidis ◽  
Dimitrios Tzovaras

Energy demand and generation are common variables that need to be forecast in recent years, due to the necessity for energy self-consumption via storage and Demand Side Management. This work studies multi-step time series forecasting models for energy with confidence intervals for each time point, accompanied by a demand optimization algorithm, for energy management in partly or completely isolated islands. Particularly, the forecasting is performed via numerous traditional and contemporary machine learning regression models, which receive as input past energy data and weather forecasts. During pre-processing, the historical data are grouped into sets of months and days of week based on clustering models, and a separate regression model is automatically selected for each of them, as well as for each forecasting horizon. Furthermore, the multi-criteria optimization algorithm is implemented for demand scheduling with load shifting, assuming that, at each time point, demand is within its confidence interval resulting from the forecasting algorithm. Both clustering and multiple model training proved to be beneficial to forecasting compared to traditional training. The Normalized Root Mean Square Error of the forecasting models ranged approximately from 0.17 to 0.71, depending on the forecasting difficulty. It also appeared that the optimization algorithm can simultaneously increase renewable penetration and achieve load peak shaving, while also saving consumption cost in one of the tested islands. The global improvement estimation of the optimization algorithm ranged approximately from 5% to 38%, depending on the flexibility of the demand patterns.


2012 ◽  
Vol 76 (1) ◽  
pp. 125-133 ◽  
Author(s):  
Eduardo H. Ramirez ◽  
Ramon Brena ◽  
Davide Magatti ◽  
Fabio Stella
Keyword(s):  

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 961
Author(s):  
Vignesh Rajamanickam ◽  
Heiko Babel ◽  
Liliana Montano-Herrera ◽  
Alireza Ehsani ◽  
Fabian Stiefel ◽  
...  

In bioprocess engineering the Qualtiy by Design (QbD) initiative encourages the use of models to define design spaces. However, clear guidelines on how models for QbD are validated are still missing. In this review we provide a comprehensive overview of the validation methods, mathematical approaches, and metrics currently applied in bioprocess modeling. The methods cover analytics for data used for modeling, model training and selection, measures for predictiveness, and model uncertainties. We point out the general issues in model validation and calibration for different types of models and put this into the context of existing health authority recommendations. This review provides a starting point for developing a guide for model validation approaches. There is no one-fits-all approach, but this review should help to identify the best fitting validation method, or combination of methods, for the specific task and the type of bioprocess model that is being developed.


2020 ◽  
Vol 34 (04) ◽  
pp. 6283-6290 ◽  
Author(s):  
Yansheng Wang ◽  
Yongxin Tong ◽  
Dingyuan Shi

Latent Dirichlet Allocation (LDA) is a widely adopted topic model for industrial-grade text mining applications. However, its performance heavily relies on the collection of large amount of text data from users' everyday life for model training. Such data collection risks severe privacy leakage if the data collector is untrustworthy. To protect text data privacy while allowing accurate model training, we investigate federated learning of LDA models. That is, the model is collaboratively trained between an untrustworthy data collector and multiple users, where raw text data of each user are stored locally and not uploaded to the data collector. To this end, we propose FedLDA, a local differential privacy (LDP) based framework for federated learning of LDA models. Central in FedLDA is a novel LDP mechanism called Random Response with Priori (RRP), which provides theoretical guarantees on both data privacy and model accuracy. We also design techniques to reduce the communication cost between the data collector and the users during model training. Extensive experiments on three open datasets verified the effectiveness of our solution.


Author(s):  
Mian Lu ◽  
Ge Bai ◽  
Qiong Luo ◽  
Jie Tang ◽  
Jiuxin Zhao

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