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Data-driven construction of maritime traffic networks for AI-based route prediction
Get PDFPredicting the routes of maritime traffic can improve economic efficiency, decrease ecological impact, and improve safety at sea. Over scales that are small (few hundred meters) and large (dozens to hundreds of kilometers), vessel trajectories have successfully been predicted by deep learning and (static) network-based approaches, respectively. We present an approach for medium to large scales (few kilometers) where (a) a maritime traffic network is automatically constructed from AIS messages, and (b) vessel trajectories are predicted as most likely paths through the network. Using three regions (Stavanger, Tromsø, and Oslo), we show that the network can capture up to ∼ 90 per cent of all maritime traffic (excluding pleasure craft) with a median absolute error of ∼ 80 meters. Vessel paths are sequences of waypoints and legs (nodes and edges) and are map-matched onto the network from vessel trajectories. Once mapped, we predict future paths for two subproblems – (i) known destination, and (ii) unknown destination. We use four algorithms (Dijkstra, Markov, MOGen, GRETEL). For known destinations, we find that Dijkstra performs best. In Stavanger (Tromsø, Oslo), Dijkstra predicts 64 (42, 68) per cent of path segments correctly and keeps the median path error below 15 (33 and 55) meters. For unknown destinations, performance depends on the forecast horizon (the number of legs k to predict). For k ≤ 5, Markov is best and predicts 62 (48, 72) per cent of legs correctly. For k > 5, GRETEL performs best and predicts 54 (47, 63) per cent of legs correctly. For some types of vessels, models improve by considering vessel type. For passenger vessels, models specific to them predict ∼ 10 per cent better paths with half the distance error. For tankers, paths (and distance errors) are 6 (20) per cent worse. For auxiliary vessels, path quality is unchanged, but distance error improves ∼ 36 per cent.publishedVersio
SWMMLIDopt: a tool for optimization of low-impact development (LID) measures using the SWMM model
Get PDFThe present study introduces the SWMMLIDopt tool that aims to optimize the implementation of low-impact development (LID) measures for stormwater management. The developed tool utilizes the capabilities of the stormwater management model (SWMM) and provides a user-friendly interface for conducting multi-objective optimization of the selection and placement of LID measures in urban catchments. The features and capabilities of the developed optimization tool are demonstrated on two urban catchments in Northern Europe, Norway and Finland. The catchments exhibit different catchment sizes and characteristics, complexities and constraints demonstrating the flexibility of the tool. The selection and placement of LID measures within the study catchments were optimized according to two criteria: (1) minimizing the peak flow and (2) minimizing the cost. The generated Pareto-fronts for the study catchments allow for the evaluation of optimal scenarios based on the trade-offs between the two selected criteria. The results obtained using SWMMLIDopt demonstrate its efficacy in optimizing LID measures in urban stormwater management that will aid practitioners in designing cost-effective and climate resilient infrastructure.publishedVersio
Improving energy efficiency in seafood freezing with brine technology
Get PDFSeafood is an important source of the world’s food supply and demand is growing. More and more seafood is being sold frozen, which extends the shelf life and creates more sustainable transportation options. Depending on the type of product, different freezing methods and equipment are used with a great variation in energy intensity. Brine freezing, with its good heat transfer properties, is one method that can improve the energy efficiency of this process but is not widely used. This paper explores the implications of introducing brine freezing into different seafood production chains, focused on potential reductions in energy consumption, quality attributes and practical aspects. A particular focus is placed on brine freezing of mackerel as part of a two-stage freezing process, including results from preliminary trials that show rapid freezing times but also revealed some practical barriers.acceptedVersio
Analysis of Concrete Air Voids: Comparing OpenAI-Generated Python Code with MATLAB Scripts and Enhancing 2D Image Processing Using 3D CT Scan Data
Get PDFThe air void system in concrete significantly affects its mechanical, thermal, and frost durability properties. This study explored the use of ChatGPT, an AI tool, to generate Python code for analyzing air void parameters in hardened concrete, such as total air void content (A), specific surface (α), and air void spacing factor (L). Initially, Python scripts were created by requesting ChatGPT to convert MATLAB scripts developed by Fonseca and Scherer in 2015. The results from Python closely matched those from MATLAB when applied to polished sections of seven different concrete mixes, demonstrating ChatGPT’s effectiveness in code conversion. However, generating accurate code without referencing the original MATLAB scripts required detailed prompts, highlighting the need for a strong understanding of the test method. Finally, a Python script was applied to modify void reconstruction in 2D images into 3D by stereology, and comparing this with (3D) CT scanner results, showing comparable results.publishedVersio
Multi-Hardware-in-the-Loop Laboratory Testing of Power Converters and Intelligent Electronic Devices for Large-Scale Power System Applications
Get PDFThis paper presents an approach and a corresponding laboratory infrastructure for multi-hardware-in-the-loop (M-HiL) testing of power converters and intelligent electronic devices (IEDs) with wide area features for power system monitoring and control. The basis for the testing environment is a digital real-time simulation (RTS) platform which can be utilized for phasor-based or hybrid phasor and electromagnetic transient (EMT) power system simulation. A high-bandwidth power amplifier is used for interfacing the real-time simulated power system to the power hardware. The necessary elements and their interfaces required for realizing the M-HiL testing are highlighted in the paper. Finally, a complete example of M-HiL tests based on real-time simulation of the Nordic 44 (N44)-bus power system model is presented. The test setup includes two phasor measurement units (PMUs) with their corresponding communication layers and a converter configuration for scaled emulation of the HVDC transmission system of an offshore wind farm. The configuration also includes a grid forming converter unit operated in parallel to the grid-side HVDC terminal. The presented test demonstrates how the grid forming converter operated as a Virtual Synchronous Machine (VSM) can provide frequency support to the Nordic power system and how this support would be recorded by the PMUs.Multi-Hardware-in-the-Loop Laboratory Testing of Power Converters and Intelligent Electronic Devices for Large-Scale Power System ApplicationspublishedVersio
Low-Viscosity Nonaqueous Sulfolane-Amine-Methanol Solvent Blend for Reversible CO2 Capture: Part II. Blend Optimization, Water Effect, and Speciation
Get PDFThis work is part II of the investigation of a low viscosity, low regeneration energy nonaqueous CO2 capture solvent blend consisting of readily available chemicals diisopropylamine (DPA)–methanol–sulfolane and featuring the monomethyl carbonate anion (MMC) as a CO2 absorption specie. The region of practical solvent composition, high CO2 capacity, low regeneration energy, and avoidance of solvent solidification at a CO2 capture condition is identified by the design of experiment methodology combined with solvent attenuated total reflectance–Fourier transform infrared and nuclear magnetic resonance monitoring and speciation analysis. Flue gas contains water vapor; hence, solvent water stability is important. The limit of solvent blend water content is determined to be 5 wt % because of MMC decomposition to DPA-bicarbonate and -carbamate.publishedVersio
Autonomous Battery Optimization by Deploying Distributed Experiments and Simulations
Get PDFNon-trivial relationships link individual materials properties to device-level performance. Device optimization therefore calls for new automation approaches beyond the laboratory bench with tight integration of different research methods. This study demonstrates a Materials Acceleration Platform (MAP) in the field of battery research based on the problem-agnostic Fast INtention-Agnostic LEarning Server (FINALES) framework, which integrates simulations and physical experiments while leaving the active control of the hardware and software resources executing experiments or simulations with the partners running the respective units. This decentralization of control is a distinctive feature of MAPs using the FINALES framework. The connected capabilities entail the formulation and characterization of electrolytes, cell assembly and testing, early lifetime prediction, and ontology-mapped data storage provided by institutions distributed across Europe. The infrastructure is used to optimize the ionic conductivity of electrolytes and the End Of Life (EOL) of lithium-ion coin cells by varying the electrolyte formulation. Trends in ionic conductivity are rediscovered and the effect of the electrolyte formulation on the EOL is investigated. Further, the capability of this MAP to bridge diverse research modalities, scales, and institutions enabling system-level investigations under asynchronous conditions while handling concurrent workflows on the material- and system-level is shown, demonstrating true intention-agnosticism.publishedVersio
Coordinate Transformation Techniques for Improved Co-Simulation in the Maritime Industry
Get PDFCo-simulation is the modular and flexible coupling of stand-alone simulation models. It promises to help unlock the maritime industry's digitalization potential, but the correct and efficient handling of coordinate systems between models is one of the unsolved challenges that stand in the way of wide-spread adoption. Here, we give a brief introduction to the problem and describe what makes it especially difficult for co-simulations. We introduce a few of the most common models and provide a list of coordinate systems and reference frames used in maritime co-simulations. Focusing on hull and gangway models, we explore general solution approaches and provide practical advice for how to handle coordinate systems in co-simulations using a vessel–gangway simulation case for illustration.publishedVersio
Introduction of hydrogen technologies to mitigate the impact of thermal consumption in a university campus
Get PDFIt is imperative for energy systems to reduce their environmental footprint in a cost-efficient manner, for which renwable energy sources (RES) and complementary technologies become desirable options to achieve said task. This is particularly the case for systems with different energy sources, as they’d be able to either address one specific type of energy demand and/or allow for the coupling of different energy carriers that would allow for technologies that normally don’t interact to start complementing each other. Therefore, this paper proposes various scenarios for the UCY campus in which hydrogen technologies would allow for the electrification of thermal demand while harnessing the surplus production coming from a solar park, which is modelled through the Integrate optimization tool and validated through DidSILENT PowerFactory. The results showcased a rise of up to 58% in self-sufficiency while the annual energy costs and CO2 emissions were reduced by 45% and 48% respectively.Introduction of hydrogen technologies to mitigate the impact of thermal consumption in a university campusacceptedVersio
Voksenagronomen - Evaluering etter seks år med nasjonal modell for voksenagronomutdanning
Get PDFEvalueringen viser at den nasjonale modellen har bidratt til et utdanningstilbud som
tilbyderskoler, deltakere og næringsliv ser stor nytte av i den spesielle situasjonen som
landbruket er i med at folk ofte har en annen yrkeskarriere før de tar over gårdsbruk.
Voksenagronomen baserer seg på pensum og faglærere for vg2 og vg3 landbruk, og har
en viktig rolle med å gi grunnleggende kunnskap til folk som skal drive gård rundt om i
landet. Samtidig er vg3 landbruk under press på grunn av lave søkertall og forslag om en
praktisk landbruksutdanning med to år skole og to år lærling. I rapporten ser vi nærmere
på hvordan voksenagronomen fungerer, hva som kan bli utslagene av slike endringer
som 2+2, og hva som kan være aktuelle veier å vurdere framover.
ISBN: 978-82-14-07192-4publishedVersio