Search

A methodology is proposed to aid parameter estimation in fundamental models of pharmaceutical processes. This methodology addresses situations with insufficient data to reliably estimate all parameters, when the estimation is complicated by uncertain independent variables. The proposed method uses an augmented sensitivity matrix to rank the combined set of parameters and uncertain inputs from most estimable to least estimable. An updated mean‐squared‐error criterion is then used to determine the appropriate parameters and inputs that should be estimated, based on the ranked list. A model for one step in a batch pharmaceutical production process with an uncertain initial reactant concentration is used to illustrate the method, revealing that the initial reactant concentration in each batch should be estimated along with three out of six model parameters. Non‐estimable parameters are fixed at their initial values to prevent overfitting. The method will aid error‐in‐variables parameter estimation in many situations involving limited data. [ABSTRACT FROM AUTHOR]

Multimodal transfer learning aims to transform pretrained representations of diverse modalities into a common domain space for effective multimodal fusion. However, conventional systems are typically built on the assumption that all modalities exist, and the lack of modalities always leads to poor inference performance. Furthermore, extracting pretrained embeddings for all modalities is computationally inefficient for inference. In this work, to achieve high efficiency-performance multimodal transfer learning, we propose VideoAdviser, a video knowledge distillation method to transfer multimodal knowledge of video-enhanced prompts from a multimodal fundamental model (teacher) to a specific modal fundamental model (student). With an intuition that the best learning performance comes with professional advisers and smart students, we use a CLIP-based teacher model to provide expressive multimodal knowledge supervision signals to a RoBERTa-based student model via optimizing a step-distillation objective loss—first step: the teacher distills multimodal knowledge of video-enhanced prompts from classification logits to a regression logit—second step: the multimodal knowledge is distilled from the regression logit of the teacher to the student. We evaluate our method in two challenging multimodal tasks: video-level sentiment analysis (MOSI and MOSEI datasets) and audio-visual retrieval (VEGAS dataset). The student (requiring only the text modality as input) achieves an MAE score improvement of up to 12.3% for MOSI and MOSEI. Our method further enhances the state-of-the-art method by 3.4% mAP score for VEGAS without additional computations for inference. These results suggest the strengths of our method for achieving high efficiency-performance multimodal transfer learning.

The basis of land management is the geomorphological zoning of the land surface, which is determined based on the same geomorphological characteristics of the zoning. Ground zoning detect land features by basic surface features such as height, slope, and slope direction. In this study, quantitative zoning of the land surface with small coefficients to the surface has been used to identify suitable areas for artificial feeding in the mountainous region of Gohar and Dasht-e Gorbayegan in Fars province. Quantitative zoning of the land surface has been performed by Evans-Shri coefficients due to the accurate determination and separation of types, faces, and surface features of the land has an important role in determining the exact land use. In this research basic models included linear, circular, and divergent models. These basic models with the dimensions of the final windows are ranked second in the MATLAB software to the level the ground is fitted to determine the fit of these models, the parameter of total squared difference has been used. In addition, the suitability of the study area for flood distribution in five different classes was determined using fuzzy logic. The most suitable areas for feeding downstream of the cones had five parameters with a maximum score of 20. The inappropriate class related to the lower plains of alluvial fans have a minimum score of five input classes in fuzzy logic, which is equal to zero.

The basis of land management is the geomorphological zoning of the land surface, which is determined based on the same geomorphological characteristics of the zoning. Ground zoning detect land features by basic surface features such as height, slope, and slope direction. In this study, quantitative zoning of the land surface with small coefficients to the surface has been used to identify suitable areas for artificial feeding in the mountainous region of Gohar and Dasht-e Gorbayegan in Fars province. Quantitative zoning of the land surface has been performed by Evans-Shri coefficients due to the accurate determination and separation of types, faces, and surface features of the land has an important role in determining the exact land use. In this research basic models included linear, circular, and divergent models. These basic models with the dimensions of the final windows are ranked second in the MATLAB software to the level the ground is fitted to determine the fit of these models, the parameter of total squared difference has been used. In addition, the suitability of the study area for flood distribution in five different classes was determined using fuzzy logic. The most suitable areas for feeding downstream of the cones had five parameters with a maximum score of 20. The inappropriate class related to the lower plains of alluvial fans have a minimum score of five input classes in fuzzy logic, which is equal to zero. [ABSTRACT FROM AUTHOR]

The gas–liquid streams in valve columns are likely to surge at low gas velocities, which degrades tray performances and threatens production safety. Therefore, the gas–liquid surging mechanism and vibration properties were investigated in this article. First, the theory of gas–liquid unstable flow at the seal point was proposed based on the principle of lowest energy. Then, the evolution mechanism, gas–liquid flow characteristics, and essential condition of surging are proposed. Meanwhile, experiments were carried out in a Φ580 mm valve column; the frequency spectral and hydraulic characteristics of surging were in accordance with the expected surging mechanism. Moreover, the surging vanish point criterion and safe operating superficial gas velocity for valve columns were advanced. Finally, fundamental models for surging frequency and amplitude were established. The models are in close accordance with the experimental data, which suggests that they could accurately describe the surging behavior. [ABSTRACT FROM AUTHOR]

In this paper, we introduce a parsimonious fundamental model for the German day-ahead market. The methodology approximates the supply stack by a piecewise linear function and considers fundamental information, e.g. power plant availabilities, must-run production and cross-border exchange. We reduce complexity by considering technology classes, uncoupled time periods and only one market area. The model accurately reproduces the hourly historical prices and electricity production volumes for most thermal production units in Germany. In a case study, we investigate the effects of the German nuclear phase-out decision. We find an additional price decrease and reduced electricity imports in the counterfactual scenario. • A parsimonious fundamental model with reduced complexity is introduced. • The Model is validated for the German day-ahead market for the years 2011-2015. • The model accurately reproduces German day-ahead spot prices and production volumes. • Case study: German nuclear phase-out decision led to higher prices. • Fossil fired production and additional imports have substituted nuclear production. [ABSTRACT FROM AUTHOR]

Given the perspective of the Swiss energy policy to support investments in renewable energy sources, it becomes highly relevant at this point to understand cross-border effects of imported electricity on the Swiss electricity prices. We found that German (Phelix) and Swiss (Swissix) electricity prices are cointegrated, given that the two markets are interconnected. We examined the cross-border effects of the German market fundamentals on Swissix, taking into account seasonality aspects. In the context of a dynamic fundamental model, we found that there is a continuous adaption process of electricity prices to market fundamentals and that this effect depends on the season of the year and the time of the day. Model results reveal the substitution effect between traditional fuels and renewable energies due to their alternative use in production and the shift in the merit order curve. Results are of great relevance to Swiss policy makers: Switzerland imports lower electricity prices due to the energy transition in Germany. In particular, because of the high infeed of PV (photovoltaic) during peak hours, the spread between Swissix peak and off-peak prices narrowed significantly over time. Incentives for investments in renewable energies in Switzerland as well as subsidies for hydropower should be considered in the light of these insights.

A dynamic fundamental model was developed linking processes from the microscopic scale to the equipment scale for batch froth flotation. State estimation, fault detection, and disturbance identification were implemented using the extended Kalman filter (EKF), which reconciles real-time measurements with dynamic models. The online measurements for the EKF were obtained through image analysis of froth images that were captured and analyzed using the commercial package VisioFroth (Metsor Minerals). The extracted image features were then correlated to recovery using principal component analysis and partial least squares regression. The performance of real-time state estimation and fault detection was validated using batch flotation of pure galena at various operating conditions. The image features that were strongly representative of recovery were identified, and calibration and validation were performed against off-line measurements of recovery. The EKF successfully captured the dynamics of the process by updating the model states and parameters using the online measurements. Finally, disturbances in the air flow rate and impeller speed were introduced into the system, and the dynamic behavior of the flotation process was successfully tracked and the disturbances were identified using state estimation. [ABSTRACT FROM AUTHOR]

We investigate the performance of two hybrid forecasting models to predict the next-day base load electricity prices on the APX power exchange for Great Britain. Hybrid models have often been advocated as a synthetic method for forecasting, but it is an open question how well they perform at the day-ahead stage. A conventional hybrid approach combines a fundamental model, formulated with supply stack modeling, with an econometric model using data on price drivers. We extend this model to one based upon logistic smooth transition regression, which represents a regime-switching for periods of structural change. Empirical results for out-of-sample forecasting using both hybrid approaches are discussed and compared to non-hybrid time series forecasting methods. [ABSTRACT FROM PUBLISHER]

The purpose of this research is to build an operational model of developing pedagogical competences at the disciplines in the Language and Communication Curricular Area. Our study focuses on two objectives: a) the content analysis of theoretical models, educational policies and curricular documents at national and international level regarding pedagogical competences, and b) the identification of the specific categories of competences that will form the operational model. The operational categories of competences were subjected to expertise of a group of 50 specialists in the field of Educational Sciences in higher education and the paper presents the results of the semi-structured interview, thus offering both theoretical results and statistical data about the types of pedagogical competences involved in teaching languages. [ABSTRACT FROM AUTHOR]

Abstract: The devolatilization is the basic step of thermochemical processes and requires a fundamental characterization. Three biomass residues (rice husks, olive cake, cacao shells) are studied here in a thermogravimetric (TG) balance. The effect of the heating rate (HR) is evaluated in the range 5–100K/min providing significant parameters for the fingerprinting of the fuels. Kinetics are obtained by applying traditional isoconversional methods. The activation energy as function of the conversion reveals the multi-step nature of the biomass devolatilization. Although average values allow the reactivity of different fuels to be compared, a first order reaction model can hardly predict the biomass devolatilization. A VEB (Variable activation Energy model for Biomass devolatilization) model is developed, basing on the results of the kinetic analysis. A good agreement is obtained for the biomass residues in all HR runs in the entire range of temperatures. Similarities in the optimized E VEB curves for the three fuels of this work suggest to pursue a generalization in the approach, enlarging the number and variety of fuels studied. [Copyright &y& Elsevier]

A neural network-based strategy for detection of feedstock variations in a continuous pulp digester is presented. A feedforward two-layer perceptron network is trained to detect and isolate unmeasured variations in the feedstock. Training and validation data sets are generated using a rigorous first principles model. The most important issue discussed here is the design of the data set required to train the artificial neural network. Efficiency and limitation of such an approach are demonstrated using simulations. [Copyright &y& Elsevier]

[Display omitted] • A kinetic model for electrocoagulation with aluminum electrodes was suggested; • It involves electrolysis, dissociation, hydrolysis, ionic, adsorption and flotation reactions; • It obeys the laws of mass conservation, Ohm's and Faraday's laws; • It describes properly the removal of pollutant parameters from brewery effluent; • Phosphate ions, residual soluble aluminum, turbidity, hexoses and COD were examined. A kinetic model based on electrochemical principles, elementary reactions and phase equilibrium was constructed to describe electrocoagulation. The approach was successfully illustrated for the removal of phosphate ions and other pollutant parameters from a brewery effluent. The kinetic results were obtained from a factorial design of experiments at optimal conditions for removal of phosphate and COD. Al3+ from the electrolysis of zero-valent aluminum reacted with phosphate at a rate constant of ~8.16 × 107 L mol−1 s−1 to form aluminum phosphate. Hexose sugars adsorbed on aluminum phosphate at a rate constant of ~5.34 × 102 L mol−1 s−1 were removed by flotation at the same rate of COD. The concentration of soluble aluminum was dependent on multiple reactions involving aluminum species and on the equilibrium between soluble and solid aluminum species. Turbidity was associated with the formation of aluminum phosphate and its removal by flotation at a rate constant of ~1.49 × 10−3 s−1. [ABSTRACT FROM AUTHOR]

• A fundamental model is developed for column flotation. • The performance of a hybrid column with an agitated section is analyzed. • Grade, recovery and gas holdup profile are predicted. • The hybrid column is predicted to outperform a conventional column. A comprehensive dynamic fundamental model with Danckwerts' boundary conditions at the pulp/froth interface has been developed for a continuous hybrid flotation column that includes a mechanically agitated section at the bottom. The model accounts for three phases, namely the water, gas, and solid particles (hydrophobic and hydrophilic), in one space dimension. The modeling framework is based on three subsystems, including a well-mixed reactor and two plug-flow reactors representing pulp (collection) and froth (cleaning) zones that are interconnected through the boundaries. The model considers the micro-scale processes taking place in the column, such as bubble-particle attachment and bubble coalescence. The resulting mathematical model is a coupled set of nonlinear heterodirectional hyperbolic partial differential equations for the pulp and the froth and a set of ordinary differential equations for the well-mixed zone. The movement between phases are given by liquid upflow, liquid downflow, and gas upflow. An important parameter in this simulation is the bubble size, which directly affects the gas holdup, and consequently the distributions of all states, including the concentration of attached minerals through the column. Qualitative validation of the model is provided by testing its predictions against experimental data from the literature for two-phase systems. Finally, the effect of some important parameters such as gas flow rate, agitation, particle size on gas holdup, distributions of value minerals, grade, recovery, and attachment/detachment rates have been studied. [ABSTRACT FROM AUTHOR]

Given the perspective of the Swiss energy policy to support investments in renewable energy sources, it becomes highly relevant at this point to understand cross-border effects of imported electricity on the Swiss electricity prices. We found that German (Phelix) and Swiss (Swissix) electricity prices are cointegrated, given that the two markets are interconnected. We examined the cross-border effects of the German market fundamentals on Swissix, taking into account seasonality aspects. In the context of a dynamic fundamental model, we found that there is a continuous adaption process of electricity prices to market fundamentals and that this effect depends on the season of the year and the time of the day. Model results reveal the substitution effect between traditional fuels and renewable energies due to their alternative use in production and the shift in the merit order curve. Results are of great relevance to Swiss policy makers: Switzerland imports lower electricity prices due to the energy transition in Germany. In particular, because of the high infeed of PV (photovoltaic) during peak hours, the spread between Swissix peak and off-peak prices narrowed significantly over time. Incentives for investments in renewable energies in Switzerland as well as subsidies for hydropower should be considered in the light of these insights. [ABSTRACT FROM AUTHOR]