Linköping Electronic Conference Proceedings
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Reconsidering (Service) Design in View of Systemic Challenges: Insights from a Quantum Theoretical Perspective
Get PDF(Service) designers must increasingly navigate complex and interconnected challenges in their daily work. In response, new design practices are emerging that are more systemic and strategic in their orientation. However, there is insufficient discussion about, or questioning of, the onto-epistemological foundations of design and their appropriateness in the emerging context. This paper aims to support the service design discipline in its transition towards conceiving of and responding to systemic challenges as entangled phenomena. To do so, we draw on quantum mechanics, specifically a Baradian view, which centres on the notion of entanglement and enactment to understand and navigate the world. We propose an alternative theoretical foundation for (service) design that considers ontoepistemological building blocks about the world we live in and its elements, assisting designers to question potentially taken-for-granted, yet limiting assumptions and perspectives
A “Mirror for All Traitors”. Captured Ciphertexts from a Portuguese Spy in Dutch Brazil (1646)
Get PDFA deciphering report found in the National Archives at The Hague presents an intriguing story. A Portuguese spy inside the walls of Recife gathered information about the Dutch defences and wrote it in encrypted letters addressed to the Portuguese rebels that besieged the heart of the Dutch West India Company (WIC) administration in Brazil. The encrypted letters were delivered to the Dutch authorities, who summoned a Jewish cryptanalyst to read them. The report of Abraham de Pina contains a detailed description of the process he used to decipher these letters and presents the complete content of all four ciphertexts. In this paper, we will reconstruct the events of this case and analyze the design of the nomenclature cipher used by the Portuguese rebels. We also will present the flow of information of these intercepted letters within the WIC in Brazil and between them and their company superiors, the Gentlemen XIX, in the Netherlands
Situating ciphers among alchemical techniques of secrecy
Get PDFThis paper offers a contextual framework for the historical analysis of alchemical ciphers. It argues that they differ from other ciphers due to their unique context: the alchemical tradition embodies a performative culture of secrecy, which employs a variety of techniques to achieve this performance. This paper contends that the distinction between ‘secret as content’ versus ‘secrecy as practice’ presents a useful framework for understanding alchemical rhetorics of secrecy and their relationship to alchemical cryptography. Additionally, it demonstrates how these principles can be applied in interpreting several examples
Transient Simulation of an Air-source Heat Pump under Cycling of Frosting and Reverse-cycle Defrosting
Get PDFFrost accumulation is a common but undesired phenomenon for air-source heat pump (ASHP) systems in winter operations. Reverse-cycle defrosting that applies heat to the outdoor coil by reversing the thermodynamic cycle, is one of the predominant means for periodic removal of the accumulated frost. This paper presents a dynamic modeling framework for ASHPs under cycling of frosting and reverse-cycle defrosting operations. A uniform model structure was applied to frost formation and melting models, which were incorporated into the evaporator model, without a need for reinitializing the system when the operating mode switches between heating and defrosting. The developed model was simulated to predict transients of a residential ASHP under multiple cycles of frosting and defrosting operations, and results yielded good agreement with measurements
Towards an Open Platform for Democratized Model-Based Design and Engineering of Cyber-Physical Systems
Get PDFThis paper reports on the development of GitWorks, an open platform for democratizated Model-Based Design of cyber-physical systems (CPS). The GitWorks platfor is currently under development by Perpetual Labs Ltd in collaboration with the Open Source Modelica Consortium (OSMC)1 and the OpenCAESAR project2. In this paper, we present our vision for the platform, its system architecture and a prototype implementation. We also present a case study that demonstrates the use of the proposed platform for enabling the seamless integration of Modelica models into a broader range of systems engineering processes for complex product development. In the longterm, the platform also aims to enable the integration of Modelica tools with advanced systems engineering processes that rely on other domain specific languages (e.g. SysML v2, BPMN, etc.)
A renewable heat plant Modelica library for dynamic optimization with Optimica
Get PDFAlmost half of the energy consumed globally is under the form of heat, produced mainly through fossil fuels. Switching to using renewable energy instead is a real challenge. Combining renewable thermal energy with thermal storage is a complex system to operate. To harness the full potential of thermal plants, advanced control strategies need to be implemented. Dynamic real-time optimization (DRTO) seems promising to fine tune controller setpoints of plants. The goal of our study is to ultimately enable DRTO by using Optimica because of its ease of use and Modelica’s modularity. This paper presents a Modelica library developed to first perform offline dynamic optimization with Optimica, and would ultimately be used in a DRTO strategy. The library enables to model a renewable thermal plant composed of solar thermals, heat pumps and thermal storages. The model of each subcomponent has been validated. Initial dynamic optimizations of plant operation give promising results
Comparative Study and Validation of Photovoltaic Model Formulations for the IBPSA Modelica Library based on Rooftop Measurement Data
Get PDFDomain-overarching system models are crucial to investigate sector coupling concepts. Specifically, the coupling of building and electrical energy systems becomes crucial to integrate renewable energy sources such as photovoltaic power systems (PV). For such interdisciplinary simulation models, Modelica is a suitable language. However, most open-source Modelica libraries are either domain-specific or lack simple-to-parameterize PV models. We close this gap by developing a PV model for the IBPSA Modelica library. The model comprises two I-V-characteristic models and three mounting-dependent approaches to calculate the cell temperature. The I-V-characteristic models follow a single- and two-diodes approach. This study uses measurement data from a rooftop PV system in Berlin, Germany, for validation. The focus lies on comparing the implemented single- and two-diodes approach. Results prove that both models accurately calculate the modules’ DC power output and cell temperature. The two-diodes approach slightly outperforms the single-diode one at the expense of a higher parameterization effort
A Graph-Based Meta-Data Model for DevOps: Extensions to SSP and SysML2 and a Review on the DCP standard
Get PDFComputer simulation has become a vital tool for modeling complex systems. However, the development and deployment of simulation models often involve multiple stages, tools, and teams, which can lead to significant challenges in maintaining quality, reliability, and efficiency. DevOps, a set of practices that combines software development and IT operations, has emerged as a promising approach to streamline the simulation development. However, most system engineers are not DevOps specialists and there are a lot of manual steps involved when writing build pipelines and configurations of simulations. For this purpose, an abstract graph-based meta-data model was presented in previous work to provide an automation framework for DevOps with simulations. In this work we want to continue our investigations by expanding and harmonizing this approach to better work with established standards like SSP, SysML2 and DCP and demonstrating it's application on real-life use cases
A Modelica Library to Add Contact Dynamics and Terramechanics to Multi-Body Mechanics
Get PDFThe Contact Dynamics library extends the multi-body Modelica Standard Library with contact calculation to the environment, namely soft soil and hard obstacles. A focus is on terramechanics, i. e. wheels driving on soft and dry soil, and a handful of models are implemented. Additionally, a Hertz contact model for hard and elastic contact, between bodies themselves or to obstacles in the environment (e. g. rocks in the soft soil), is available as well. The capabilities of the library have been key in the development of rovers for planetary exploration such as the upcoming MMX mission to the Martian moon Phobos
MoCITempGen: Modelica Continuous Integration Template Generator
Get PDFModelica enables an object-oriented approach to model complex systems in product development and research, and, thus, the development of various model libraries. Library development requires collaborative development in a team of multiple developers. A typical challenge in collaborative development, especially in the area of open source, is to create models of uniform quality despite different levels of knowledge among developers. Techniques such as Continuous Integration (CI) from the field of software development, can help to solve these challenges. However, the adaptation of CI for the area of Modelica model development currently requires the manual creation of complex templates and a high degree of manual configuration. In this paper we present MoCITempGen, an open source tool for automated generation of CI structures for the widely used modeling language Modelica. The tool is succesfully applied on two Modelica libraries to demonstrate the functionality