Linköping Electronic Conference Proceedings
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[Industrial paper] Digital Twin Applications Using a Cloud Native Modelica Platform
Get PDFThis paper showcases how Modelica technology can be leveraged for real-time applications using a cloud native simulation platform, Modelon Impact™. The platform allows for real-time, two-way communication of data, from the IoT connected plant to a physical model and, from the physical model to a dashboard for plant monitoring and control. The communication relies on open standards and REST-API, which makes it possible to implement digital twins for various applications, such as plant monitoring, predictive maintenance, fault isolation or controls. The paper describes a state estimation workflow where data is transmitted back and forth to the simulation platform via Message Queuing Telemetry Transport (MQTT) and where Node-Red is used for the end-user interface
Advanced open source data formats for geometrically and physically coupled systems
Get PDFNumerical calculations based on models are nowadays standard tools in all engineering disciplines. The tools, which faciliate the modeling, generally include all tasks in an engineering workflow. These tasks range from simple model descriptions to advanced visualization of results.
While the incorporation of all tasks in one tool fits neatly into a single-person scheme, it makes teamwork with shared tasks very hard. In particular, every member of the team has to use the exact same software, and every sub-task has to be available in the tool. This requirement, in turn, makes a joint development of advanced methods unnecessarily complicated. Especially the numerical analysis of problem tailored methods requires a detailed knowledge of all model ingredients.
The basis for joint workflows and teamwork are interfaces and common data formats. In this publication, we briefly present a workflow and derive the needs and requirements for data formats. Finally, we discuss the state-of-the-art techniques and explain how the described formats fit into them.
Numerical calculations based on models are nowadays standard tools in all engineering disciplines. The tools, which faciliate the modeling, generally include all tasks in an engineering workflow. These tasks range from simple model descriptions to advanced visualization of results.
While the incorporation of all tasks in one tool fits neatly into a single-person scheme, it makes teamwork with shared tasks very hard. In particular, every member of the team has to use the exact same software, and every sub-task has to be available in the tool. This requirement, in turn, makes a joint development of advanced methods unnecessarily complicated. Especially the numerical analysis of problem tailored methods requires a detailed knowledge of all model ingredients.
The basis for joint workflows and teamwork are interfaces and common data formats. In this publication, we present a data format for geometrically and physically coupled systems. The data formats structure bases on the standardized format JSON, whereas the content is derived from a mathematical model. Finally, for presentational purposes, we present an instance of a simplified model
Swedish MuClaGED: A new dataset for Grammatical Error Detection in Swedish
Get PDFThis paper introduces the Swedish Mu-ClaGED dataset, a new dataset specifically built for the task of Multi-Class Grammatical Error Detection (GED). The dataset has been produced as a part of the multilingual Computational SLA shared task initiative. In this paper we elaborate on the generation process and the design choices made to obtain Swedish MuClaGED. We also show initial baseline results for the performance on the dataset in a task of Grammatical Error Detection and Classification on the sentence level, which have been obtained through (Bi)LSTM ((Bidirectional) Long-Short Term Memory) methods
Evaluating Automatic Spelling Correction Tools on German Primary School Children’s Misspellings
Get PDFMost existing spellcheckers have been developed for adults and it is yet understudied how well children’s texts can be automatically spellchecked, e.g. to build tools that assist them in spelling acquisition. This paper presents a detailed evaluation of six tools for automatic spelling correction on texts produced by German primary school children between grades 2 and 4. We find that popular off-the-shelf tools only achieve a correction accuracy of up to 46% even when local word context is taken into account. For many misspellings, the desired correction is not even among the suggested candidates. A noisy-channel model that we trained on similar errors, in contrast, achieves a correction accuracy of up to 69%. Further analyses show that this approach is very successful at candidate generation and that a better re-ranking of correction candidates could lead to a correction accuracy of ~90 %. Most of the remaining misspellings are so distorted that they are hard to correct without broader context. Furthermore, we analyze how the tools perform at different grade levels and for misspellings with different edit distances
Development of a Surrogate-model Based Energy Efficiency Estimator for a Multi-step Chemical Process
Get PDFEnergy efficiency is increasingly being considered as a critical measure of process performance due to its importance both in production costs and in environmental footprint. In this work, an indirect energy efficiency estimator was developed for the Tennessee Eastman (TE) benchmark process for the first time. The TE model was first modified to provide the reference values of energy efficiency. A sophisticated model selection scheme was then applied to build the surrogate-model. The results indicate reasonable model performance with mean absolute prediction error around 1.7%. The results also highlight the limitations present in the training set, which are, together with other practical implementation issues, discussed in this work
Validation of Hygrothermal Numerical Simulation with Experiment for Future Climate Control
Get PDFFuture climate is expected to be warmer, more humid, and cloudier with more frequent extreme weather conditions. Current building design should consider these changes as they can significantly influence the function of buildings in the future. Here, we study common building envelope assembly subjected to different climatic scenarios. An experiment was set up to validate a numerical model, which is further applied to assess hygrothermal performance (heat and moisture transfer) of the building envelope subjected to different boundary conditions. The assessment is provided via Finnish mould growth model that identifies risk of biological growth through dynamic hygrothermal conditions. Finnish meteorological institute provides data that predicts the climate in 2030, 2050 and 2100. The humidity inside the building envelope is assumed to increase slightly in time, however, increased temperature in the future may cause more favorable conditions for mould growth, especially, if mould sensitive building materials are used. The hygrothermal assessment of building structures with consideration of climate change in structural design is a key factor to provide sustainable building designs. Numerical model was successfully validated with experiments providing data within tolerances of measurement equipment
Droop Control of Hydro Power System in OpenHPL
Get PDFOpenHPL is an open-source hydro power library for modeling, design, and analysis. Currently, OpenHPL consists of mechanistic models for waterways from a reservoir to tailrace, Francis and Pelton turbine models, a simple generator model, hydro power speed governor model, etc. However, the library lacks a controller for the parallel operation of hydro powers. This paper mainly focuses on extending OpenHPL with power-frequency droop control for a multi-generator system. Two simulation case studies are carried out for the parallel operation of hydro power units
Uncertainty Analysis of a simplified 2D Control-relevant Oil Reservoir Model
Get PDFIn this paper, a simplified 2D control relevant model for a slightly slanting wedge-shaped black oil reservoir is made more realistic by incorporating model uncertainty. The uncertainty in the model is computed via Monte Carlo simulation. Furthermore, based on this model with uncertainty, a Proportional + Integral (PI) controller is implemented to increase oil production while minimizing water production. A PI controller is used to control the valve opening of the Inlet Control Valves (ICVs) in the production well. Implementation of a PI controller enhanced the oil recovery in 1000days by 1.79%, while the total water production is reduced by 2.59%
Simulation of Condensation in Biogas containing Ammonia
Get PDFCondensation in raw biogas during compression is a problem because the CO2 and water in the liquid phase is very corrosive. Raw biogas typically contains 60 mol-% methane, 40 mol-% CO2, is saturated with water and may contain contaminants as ammonia (NH3). In case of NH3, it is of interest whether it has influence on the dew point (condensation) temperature. The aim of this work is to calculate the dew point under different conditions using different equilibrium models. Phase envelopes showing the two-phase area are also calculated. For dry mixtures of methane and CO2 with up to 1 mol-% NH3 (a high value for biogas), the different models gave similar results. When the NH3 increased from 0 to 1 mol-%, the dew point temperature increased with approximately 3 K. When water was included, the amount of calculated NH3 dissolved in water varied considerably with the model. The electrolyte based models Sour PR, Sour SRK and Electrolyte NRTL did not calculate reasonable dew point temperatures, but the dissolved amounts of NH3 and CO2 were more reasonable using the electrolyte models compared to using PR or SRK. For biogas simulation including NH3, a simple equation of state as PR or SRK can be recommended to determine the dew point. If accurate composition of the condensed liquid is to be calculated, an electrolyte based model like Sour PR, Sour SRK or the Electrolyte NRTL is recommended
Covid-19 Models and Model Fitting
Get PDFThe paper discusses how to use cumulative confirmed infected numbers to find basic infection parameters. Next, an extension of the SEIR model, the SEICUR model from the literature (a renaming of the SEIRU model) is introduced, with details of how to compute the full set of model parameters, as well as the reproduction number R. A discussion is given of how the infection rate parameter relates to mitigation policy and various natural variations. Based on a simple mitigation model, an equivalent mitigation policy is found for Italy, Spain, and Norway. An indication of how to use feedback control theory to develop mitigation policy planning is given