@inbook{65749,
  abstract     = {{<jats:title>Abstract</jats:title>
                  <jats:p>Phase noise is one of the most important properties of oscillators that limit the capacity of high-frequency communication systems. In heterodyne conversion schemes, the phase noise of the local oscillator will be multiplied and up-converted to the transmission channel. Therefore, accurate characterization of the oscillators is highly important for the design of THz communication systems. Especially when it comes to the characterization of high-quality oscillators with extremely low phase noise, traceable measurement methods are not available.</jats:p>
                  <jats:p>In this chapter, the mathematical model and definition of the amplitude noise (AM noise) and phase noise (PM noise) are given. Different phase noise definition standards such as single sideband (SSB) and double sideband will also be provided. Phase noise measurement techniques such as frequency discrimination and phase-locked loop (PLL) technique will be discussed. The standard two-channel cross correlation for statistical analysis of phase noise at levels below the detection limit of the phase noise receiver will be explained with mathematical formalism.</jats:p>}},
  author       = {{Bahmanian, Meysam and Scheytt, J. Christoph and Meyne, Nora and Kleine-Ostmann, Thomas}},
  booktitle    = {{Springer Series in Optical Sciences}},
  isbn         = {{9783032019851}},
  issn         = {{0342-4111}},
  publisher    = {{Springer Nature Switzerland}},
  title        = {{{Phase Noise Metrology}}},
  doi          = {{10.1007/978-3-032-01986-8_4}},
  year         = {{2026}},
}

@inbook{65748,
  abstract     = {{<jats:title>Abstract</jats:title>
                  <jats:p>In this chapter, the precision of optical clocks based on mode-locked laser (MLL) is compared with more conventional types of clock sources. It is shown that the phase noise of the optical pulse train from the MLL can be better than other types of clock sources by orders of magnitude. Then, an abstract representation of frequency synthesizer is demonstrated. Different techniques for RF generation using MLL are shown, and their pros and cons are discussed. Finally, a comparison of all these techniques is made with respect to their phase noise and capability to generate RF signal with different frequencies for different applications.</jats:p>}},
  author       = {{Bahmanian, Meysam and Scheytt, J. Christoph}},
  booktitle    = {{Springer Series in Optical Sciences}},
  isbn         = {{9783032019851}},
  issn         = {{0342-4111}},
  publisher    = {{Springer Nature Switzerland}},
  title        = {{{Frequency Synthesis Based on MLLs}}},
  doi          = {{10.1007/978-3-032-01986-8_28}},
  year         = {{2026}},
}

@inbook{65755,
  author       = {{Twardzik, Jan Luca and Humpert, Lynn and Cichon, Gerrit and Dumitrescu, Roman}},
  booktitle    = {{Lecture Notes in Mechanical Engineering}},
  isbn         = {{9783032211569}},
  issn         = {{2195-4356}},
  publisher    = {{Springer Nature Switzerland}},
  title        = {{{Knowledge Gaps in Circular Product Development: A Systematic Literature Review of the Manufacturing Industry}}},
  doi          = {{10.1007/978-3-032-21157-6_39}},
  year         = {{2026}},
}

@article{65757,
  abstract     = {{Electrifying the heating sector is essential for achieving global climate targets like the Paris Agreement’s 1.5 °C goal. In Germany, where 80  % of household energy goes to space heating and hot water, shifting to low-carbon solutions is crucial. Fossil-fuelled district heating networks can incorporate renewable energy via heat pumps, improving efficiency. Although heat pump design typically favours minimal temperature lifts, higher lifts can be economically viable with low electricity prices and abundant renewables. Adding thermal energy storage boosts operational flexibility. This study explores a flexible heat pump operation incorporating part load behaviour with a thermal energy storage in a German city’s district heating system to minimise costs and carbon dioxide emissions. Using a mixed-integer linear programming model, it examines the impact of temperature adjustments and storage on system efficiency. The results show that the integration of a heat pump in a district heating system reduces operating costs. Compared to a supply without a heat pump, with levelised cost of heating of 9.98 cent/kWhth and a fixed operating mode with costs between 9.96 cent/kWhth and 11.49 cent/kWhth, the flexible use results in lowest costs of 9.85 cent/kWhth, while also reducing overall CO2 emissions. Using a full factorial sensitivity analysis, the levelised cost of heating ranged between 9.15 cent/kWhth in the best case and 10.37 cent/kWhth in the worst case for the selected configuration.}},
  author       = {{Rahlf, Henning Christoph and Divkovic, Denis and Knorr, Lukas and Schlosser, Florian and Meschede, Henning}},
  issn         = {{0196-8904}},
  journal      = {{Energy Conversion and Management}},
  keywords     = {{Heat transition, Optimisation, Temperature flexibility, Decarbonisation, Multi energy}},
  publisher    = {{Elsevier BV}},
  title        = {{{Flexible operation strategies for heat pumps in district heating systems using dynamic electricity prices}}},
  doi          = {{10.1016/j.enconman.2026.121714}},
  volume       = {{364}},
  year         = {{2026}},
}

@article{63838,
  abstract     = {{Industrial electrification is increasing to reduce fossil fuel dependence, alongside a growing share of volatile renewables.
A secure and reliable energy supply is crucial for industry, leading to a shift from centralised to decentralised grid structures.
DC microgrids becoming increasingly popular in industry, since they enable energy recuperation from braking, reduce components and cables, and integrate storage and local generation to manage supply interruptions or peak loads.
EVs add further synergies by serving as mobile storage units, helping to store and redistribute locally generated renewable energy.
This paper analyses how EV integration in droop-controlled DC grids can contribute to a more stable, low-emission and peak-reduced load profile to the supply grid through load shifting and bridge interruptions.
A droop-controlled DC grid model has been developed, incorporating an EV charging park based on probability functions.
Scalable scenarios allow for diverse condition analysis using an energy management system that utilises fuzzy logic and sequential MILP optimisation.
It has been shown that a 7% improvement of coefficient represented grid-serving behaviour is possible by load shifting.
It has also been demonstrated that an optimised EMS can reduce the demand-based CO2 emissions by 41kg for a representative day compared to a fuzzy logic EMS.
At the same time peak load is decreased yielding a more constant residual load.
These results highlight the potential of a controlled bidirectional charging infrastructure in DC grids and underscore the need to explicitly consider charging processes to ensure a residual load as constant as possible.}},
  author       = {{Rahlf, Henning Christoph and Knorr, Lukas and Althoff, Simon and Meschede, Henning}},
  issn         = {{2666-9552}},
  journal      = {{Smart Energy}},
  keywords     = {{DC-grid, Droop control, Grid-serving behaviour, Grid stability, Bidirectional charging, Sequential decision, MILP optimisation}},
  publisher    = {{Elsevier BV}},
  title        = {{{Analysis of bidirectional EV charging infrastructures within industrial DC grids}}},
  doi          = {{10.1016/j.segy.2026.100227}},
  year         = {{2026}},
}

@article{65785,
  abstract     = {{Simulation-based design of high-power ultrasonic systems depends on the accurate modelling of the electromechanical behaviour of piezoceramic materials. In practical transducer applications, the relevant operating points are influenced by mechanical preload and heating, both of which give rise to changes in the elastic, dielectric, and piezoelectric material properties. Material parameters identified under idealised, unloaded conditions are therefore insufficient to represent piezoceramic material behaviour under realistic operating conditions. To overcome this limitation, experimental setups are developed that enable the measurement of electrical impedance spectra under controlled thermal and mechanical conditions. The acquired impedance data are used in an inverse identification procedure, in which the behaviour of a finite element forward model is iteratively fitted to the measurements using a block coordinate descent optimisation strategy guided by a sensitivity analysis. This yields effective linear material parameters as a function of temperature and mechanical stress at varying operating points. The identified temperature-dependent parameters, for instance, can be employed in a coupled thermo-electromechanical simulation framework to predict the temperature-dependent material behaviour during operation. The linear identification based on varying operation points provides an initial approximation of the nonlinear material response, establishing a basis for the development of corresponding nonlinear material models.}},
  author       = {{Friesen, Olga and Claes, Leander and Hölscher, Jonas and Henning, Bernd and Scheidemann, Claus and Hemsel, Tobias and Kuess, Raphael and Walther, Andrea and Spieker, Carsten and Förstner, Jens}},
  issn         = {{0171-8096}},
  journal      = {{tm - Technisches Messen}},
  keywords     = {{tet_topic_piezo}},
  publisher    = {{Walter de Gruyter GmbH}},
  title        = {{{Measurement of multiphysical material parameters of piezoceramic components for high-power ultrasonic applications}}},
  doi          = {{10.1515/teme-2026-0042}},
  year         = {{2026}},
}

@inproceedings{65588,
  author       = {{Spieker, Carsten and Kuess, Raphael and Walther, Andrea and Förstner, Jens}},
  booktitle    = {{Fortschritte der Akustik - DAGA 2026}},
  keywords     = {{tet_topic_piezo}},
  pages        = {{1066–1069}},
  title        = {{{Modellierung und Simulation des temperaturabhängigen Materialverhaltens von Piezokeramiken mit FEniCS}}},
  doi          = {{10.71568/DAGA2026.549}},
  year         = {{2026}},
}

@inproceedings{65825,
  author       = {{Kürpick, Dominik and Hovemann, Aschot and Kürpick, Christian and Gabriel, Stefan and Lick, Jonas and Dumitrescu, Roman}},
  booktitle    = {{2025 International Conference on Intelligent &amp;amp; Innovative Practices in Engineering &amp;amp; Management (IIPEM)}},
  publisher    = {{IEEE}},
  title        = {{{AI-Based Enterprise Architecture Management in Engineering Domain: A Systematic Literature Review}}},
  doi          = {{10.1109/iipem65914.2025.11548261}},
  year         = {{2026}},
}

@inbook{65835,
  author       = {{Koldewey, Christian and Avermeyer, Celina Maleen and van der Valk, Hendrik and Zerbin, Julian and Dumitrescu, Roman}},
  booktitle    = {{Lecture Notes in Computer Science}},
  isbn         = {{9783032283122}},
  issn         = {{0302-9743}},
  publisher    = {{Springer Nature Switzerland}},
  title        = {{{Fundamental Patterns – A Taxonomy for Archetype Development in Information Systems}}},
  doi          = {{10.1007/978-3-032-28313-9_18}},
  year         = {{2026}},
}

@article{65834,
  author       = {{Humpert, Lynn and Disselkamp, Jan-Philipp and Cichon, Gerrit and Anacker, Harald and Dumitrescu, Roman}},
  issn         = {{0360-8581}},
  journal      = {{IEEE Engineering Management Review}},
  pages        = {{1--22}},
  publisher    = {{Institute of Electrical and Electronics Engineers (IEEE)}},
  title        = {{{Systematic Approach to Early Validation Based on the System Architecture of Advanced Systems in the B2B Sector}}},
  doi          = {{10.1109/emr.2026.3700482}},
  year         = {{2026}},
}

@inproceedings{65836,
  author       = {{Fichtler, Timm and Petzke, Lisa Irene and Grigoryan, Khoren and Koldewey, Christian and Dumitrescu, Roman}},
  booktitle    = {{Proceedings of the Annual Hawaii International Conference on System Sciences}},
  issn         = {{2572-6862}},
  publisher    = {{Hawaii International Conference on System Sciences}},
  title        = {{{Enhancing Product Management Performance through Digitalization: Advantages, Challenges, Design Fields}}},
  doi          = {{10.24251/hicss.2026.478}},
  year         = {{2026}},
}

@article{65845,
  author       = {{Kattenstroth, Fiona and Kranz, Michael and Hunger, Sebastian and Withot, Dennis and Hovemann, Aschot and Dumitrescu, Roman}},
  issn         = {{1877-0509}},
  journal      = {{Procedia Computer Science}},
  pages        = {{586--595}},
  publisher    = {{Elsevier BV}},
  title        = {{{Towards a digital factory twin: systematization of material flow simulation use cases}}},
  doi          = {{10.1016/j.procs.2026.02.100}},
  volume       = {{277}},
  year         = {{2026}},
}

@article{65838,
  author       = {{Rasor, Anja and Petzke, Lisa Irene and Koldewey, Christian and Dumitrescu, Roman}},
  issn         = {{2212-8271}},
  journal      = {{Procedia CIRP}},
  pages        = {{239--244}},
  publisher    = {{Elsevier BV}},
  title        = {{{Identifying Cost Drivers in Circular Business Model Planning: Insights from an Explorative Interview Study}}},
  doi          = {{10.1016/j.procir.2026.05.041}},
  volume       = {{140}},
  year         = {{2026}},
}

@article{65840,
  author       = {{Grigoryan, Khoren and Bauer, Eliana and Fichtler, Timm and Asmar, Laban and Kühn, Arno and Dumitrescu, Roman}},
  issn         = {{2212-8271}},
  journal      = {{Procedia CIRP}},
  pages        = {{916--921}},
  publisher    = {{Elsevier BV}},
  title        = {{{Design Principles and Process Model for Planning Data Analytics in Product Management}}},
  doi          = {{10.1016/j.procir.2026.05.154}},
  volume       = {{140}},
  year         = {{2026}},
}

@article{65839,
  author       = {{Petzke, Lisa Irene and Vehmeyer, Julia Marie and Rasor, Anja and Koldewey, Christian and Dumitrescu, Roman}},
  issn         = {{2212-8271}},
  journal      = {{Procedia CIRP}},
  pages        = {{228--233}},
  publisher    = {{Elsevier BV}},
  title        = {{{Organizational Capabilities for Implementing R-Strategies in Circular Value Networks}}},
  doi          = {{10.1016/j.procir.2026.05.039}},
  volume       = {{140}},
  year         = {{2026}},
}

@inbook{65855,
  author       = {{Twardzik, Jan Luca and Humpert, Lynn and Cichon, Gerrit and Dumitrescu, Roman}},
  booktitle    = {{Lecture Notes in Mechanical Engineering}},
  isbn         = {{9783032211569}},
  issn         = {{2195-4356}},
  publisher    = {{Springer Nature Switzerland}},
  title        = {{{Knowledge Gaps in Circular Product Development: A Systematic Literature Review of the Manufacturing Industry}}},
  doi          = {{10.1007/978-3-032-21157-6_39}},
  year         = {{2026}},
}

@article{65856,
  author       = {{Trienens, Malte and Busch, Vanessa and Wyrwich, Fabian and Hovemann, Aschot and Dumitrescu, Roman}},
  issn         = {{2212-8271}},
  journal      = {{Procedia CIRP}},
  pages        = {{1070--1075}},
  publisher    = {{Elsevier BV}},
  title        = {{{Unleashing the Potential of the Digital Product Passport in Engineering: A Structured Map for Sustainable Product Design}}},
  doi          = {{10.1016/j.procir.2026.05.394}},
  volume       = {{142}},
  year         = {{2026}},
}

@article{65837,
  author       = {{Vehmeyer, Julia Marie and Petzke, Lisa Irene and Koldewey, Christian and Dumitrescu, Roman}},
  issn         = {{2212-8271}},
  journal      = {{Procedia CIRP}},
  pages        = {{863--868}},
  publisher    = {{Elsevier BV}},
  title        = {{{The fellowship of the circle: Barriers to establishing partnerships for circular value creation}}},
  doi          = {{10.1016/j.procir.2026.05.145}},
  volume       = {{140}},
  year         = {{2026}},
}

@inproceedings{65854,
  author       = {{Wyrwich, Fabian and Trienens, Malte and Hovemann, Aschot and Dumitrescu, Roman}},
  booktitle    = {{2025 IEEE International Conference on Technology Management, Operations and Decisions (ICTMOD)}},
  publisher    = {{IEEE}},
  title        = {{{Fields of Action of a Digital Engineering Transformation Framework}}},
  doi          = {{10.1109/ictmod66732.2025.11371934}},
  year         = {{2026}},
}

@article{65865,
  abstract     = {{Mathematical problem solving is a highly complex competence that needs
to be supported throughout the learning process. This study examines the role of
problem-solving heuristics among 73 sixth-grade students in a German secondary
school (Gesamtschule). Specifically, we focus on the empirical relationship between
the occurrence of heuristics, their suitability, and application, as well as their contribution
to problem-solving success. To this end, we developed a heuristic training that
introduced strategy keys (heuristic aid cards) accompanied by explanatory videos. By
leveraging variations in the successful application of the heuristics between students
and across multiple sessions (73 students in 4 training situations and 3 problems
in a final test), we discover from regression models with student and task-fixed effects
that a successful use of heuristics (i.e., an heuristic occurred, that heuristic had
a high suitability regarding the problem, and it was applied correctly) leads to more
successful mathematical problem solving. Regarding the underlying mechanism, we
find that all dimensions of heuristic use (occurrence, suitability, and application
of heuristics) are positively related to problem-solving success. When comparing
the predictive capacity of all three aspects, we identified the correct application of
heuristics as particularly conducive for better problem-solving success. In comparing
the group of students with high to those with low initial math competence, we find no significant differences in the relationship between heuristic use and problemsolving
success across achievement groups. Our results emphasize the crucial role
of heuristic application in mathematical problem solving, which generally benefits
students regardless of their overall math competence.}},
  author       = {{Herold-Blasius, Raja and Kleinschmidt, Hannah and Ziller, Conrad}},
  journal      = {{Journal für Mathematik-Didaktik}},
  number       = {{6}},
  title        = {{{Dimensions of Heuristic Use in Mathematical Problem Solving: Evidence from Early Secondary School Students}}},
  doi          = {{https://doi.org/10.1007/s13138-026-00270-6}},
  volume       = {{47}},
  year         = {{2026}},
}