Linköping Electronic Conference Proceedings
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Encrypted Documents and Cipher Keys From the 18th and 19th Century in the Archives of Aristocratic Families in Slovakia
Get PDFIn this article, we present encrypted documents and cipher keys from the 18th and 19th century, related to central-European aristocratic families Amade-Üchtritz, Esterházy, and Pálffy-Daun. In the first part of the article, we present an overview and analysis of the available documents from the archives with examples. We provide a short historical overview of the people related to the analyzed documents to provide a context for the research. In the second part of the article, we focus on the digital processing of these historical manuscripts. We developed new tools based on machine learning that can automate the transcription of encrypted parts of the documents, which contain only digits as cipher text alphabet. Our digit detection and segmentation are based on YOLOv7. YOLOv7 provided good detection precision and was able to cope with problems like noisy paper background and areas where digits collided with the text from the reverse side of the paper
What is the Code for the Code? Historical Cryptology Terminology
Get PDFThe cross-disciplinary nature of historical cryptology involves the challenge to find a terminology that is both consistent and accepted across the different disciplines and applicable in the single fields. In this paper, we propose a terminology based on concise principles developed by an interdisciplinary group of researchers. We present terms prominent in the study of historical cryptology, define them, and illustrate their usage. Our goal is to initiate and/or continue the discussion of how we use various terms for different types of historical encrypted sources, and their study. Our hope is that this paper will contribute to consistent and systematic usage of terms in the HistoCrypt community
BESMod - A Modelica Library providing Building Energy System Modules
Get PDFTowards the analysis and optimization of a coupled building energy sector, various component model libraries for hydraulic, ventilation, electrical, control, and building domains exist. However, no uniform open-source framework to couple these domains in a holistic building energy system simulation exists. Thus, we present BESMod, an open-source Modelica library, providing a modular approach towards domain-coupled building energy system simulations. BESMod relies on existing component specialized model libraries for the underlying physics. For the analysis of complex system simulations, user-friendly parameterization, consistent model interfaces, precalculated KPIs and debugging options are applied. The library is available at www.github.com/RWTH-EBC/BESMod. This paper motivates the library, lays out the interaction with existing model libraries and the general modular approach. An exemplary use case demonstrates the applicability of BESMod. Concluding, we motivate future development options
Using Multi-Physics Simulation to Estimate Energy Flexibility for Local Demand Response Strategies in a Microgrid
Get PDFThis work discusses the development of a multi-physics simulated model, in the frame of the decarbonization and energy efficiency objectives of the European Commission. Its central feature is the interconnection, through a microgrid, of a distributed PV installation and of several electric dispatchable loads, thus powering a Collective Self-Consumption network. The simulator presented within this document aims to serve as a technological enabler for the design and testing of On-Site DR strategies, which actuate directly on the connection status of the loads, before their deployment on the target, real-world systems. The simulator supports the design and validation of such strategies by generating realistic simulated data of certain loads that present monitoring difficulties, taking into account online, real external weather conditions. All the elements described and modeled in the current work belong to a real-world installation, which is a university campus—ESTIA, Bidart, France— composed by several buildings with DER
MoPyRegtest: A Python package for continuous integration-friendly regression testing of Modelica libraries
Get PDFRegression testing is a commonly used strategy in continuous integration workflows to ensure reproduceability of outputs. It is widely in software engineering and model development, including Modelica. In this article we introduce the open source regression testing framework MoPyRegtest written in Python. Its primary focus is to provide Modelica library developers with a simple regression testing tool that features test automation and can integration with continuous integration toolchains, in particular for open source developments. In order to simulate the Modelica models for testing analysis, we provide an interface to Modelica simulation tools that support Modelica Scripting with .mos files. Our current implementation works with OpenModelica. We outline the design and functionality of MoPyRegtest and showcase its potential usefulness for open source development of Modelica models and libraries
Paving the way for Hybrid Twins using Neural Functional Mock-Up Units
Get PDFPorting Neural Ordinary Differential Equations (NeuralODEs), the combination of an artificial neural network and an ODE solver, to real engineering applications is still a challenging venture. However, we will show that Neural Functional Mock-up Units (NeuralFMUs), an evolved subgroup of NeuralODEs that contain Functional Mock-up Units (FMUs), are able to cope with these challenges. This paper briefly introduces to the topics NeuralODE and NeuralFMU and describes the procedure and considerations to apply this technique to a real engineering use case. Further, different workflows to apply NeuralFMUs dependent on tool capabilities and use case requirements are discussed. The presented method is illustrated with the creation of a Hybrid Twin of an hydraulic excavator arm, which has various challenges such as discontinuity, nonlinearity, oscillations and characteristic maps. Finally we will show, that the created Hybrid Twin, on basis of measurement data from a real system, gives more accurate results compared to a conventional simulation model based on first principles
Modelica 3.6 - Changes, Benefits and Implementation
Get PDFThe latest release of the Modelica Language Specification version 3.6 brings several benefits to users, and this paper will discuss the changes and the benefits for the clearer parameter defaults, clearer start-value priority, selective model extension, and multi-lingual support. The benefits only occur when the features are implemented in Modelica tools, and to facilitate that, the paper will discuss the design choices when implementing the new standard in Dymola 2023x Refresh 1 and 3DEXPERIENCE 2023x FD03
Electrode boiler model for ancillary service simulation
Get PDFA generic component-based model of an industrial electrode boiler with internal control systems is presented. A mechanistic modelling approach was taken to include as much process and control information as possible and to generate detailed simulation results. The model is intended for qualitative studies of electrode boiler dynamics in the context of district heating generation and power grid ancillary services in collaboration with other electric power consuming units. An example boiler control scheme is designed and included in the simulation model as this is paramount to the dynamic response of the system. Simulations of standstill, load changes, and startup from hot and cold state show that the strictest ancillary service requirements can be fulfilled when the boiler is kept at operating temperature
Switching and Averaging Models of a Bidirectional, Half-Bridge Based DC-DC converter with Load Distribution
Get PDFBatteries are used in numerous applications such as mobile devices, electric vehicles, home storage systems and islanded microgrids. Bidirectional DC-DC converters are vital for the integration of batteries, for the power conversion during (dis)charge and the battery management. Modeling of these is helpful, especially for the design of larger, more complex systems consisting of multiple DC-DC converters in parallel. Due to the high switching frequencies, the simulation of DC-DC converters is associated with increased computational time and effort. In this paper, three models of different complexity and accuracy are proposed for a bidirectional DC-DC converter consisting of two phase-shifted half-bridges. Two switching models, which differ mainly in the way the mosfets are driven, account for the individual switching operations and exhibit high accuracy. An averaging model replaces the switching elements with current and voltage sources providing the mean values. It is particularly suitable for multiple components and longer simulation durations. The dynamic behavior of the models is analyzed using the step responses of the load current. For validation, these are compared with the theoretical transfer function. The three models are analyzed comparatively in terms of computational time and effort. The calculation time of the averaging model has been reduced by two thirds compared to the strictly complementary switching model and by 96% relative to the model with diode emulation mode. The averaging model requires only one third of the computation time of the complementary switching model and only 3.5% of that of the model with diode emulation. Recommendations for the use of the models are given and a possible use case is shown. Two parallel connected DC-DC converters with load current sharing between them are simulated using the averaging model
Mass Conservation in Vapor Compression Cycles: A Method for Ensuring Consistency with Redundant Dynamic States
Get PDFThis paper describes a method to resolve a potential inconsistency when employing redundant dynamic thermofluid states for modeling of vapor compression cycles. Following a brief introduction regarding the motivation and use of redundant thermofluid states, a series of test models ranging from simple component models to complex system models are developed to illustrate the potential inconsistency with Air Conditioning Library. Based on observations of the simulation results from these test models, a method for ensuring consistency is proposed and implemented. The method is then demonstrated on the test suite and evaluated for effectiveness, robustness, and computational efficiency