275003 research outputs found
Sort by
Potential of Tetrahedral Markers for Infrared Pose Tracking in Surgical Navigation
No full textOptical tracking systems predominantly rely on spherical retro-reflective markers, requiring a minimum of three fiducials to achieve a full six-degree-of-freedom (6D) pose estimation. Despite the potential benefits of a single non-spherical fiducial for 6D pose estimation, this approach has received limited attention in the literature. This study investigates the feasibility of non-spherical retro-reflective markers, specifically tetrahedral markers, as alternatives to spherical fiducials. Using Blender for simulation and digital post-processing, stereo images of both spherical and tetrahedral markers were generated. The standard marker tracking is adapted to use the tetrahedrons corners instead of sphere centers. Results indicate that while spherical markers provide slightly more precise tracking in the simulated scenario, tetrahedral markers offer advantages in practical applications, such as an enhanced range of motion. These findings suggest that non-spherical markers warrant further exploration for their potential to improve optical tracking systems in real-world settings
Plastic Waste Recycling─A Chemical Recycling Perspective
No full text1227012288This article provides an overview of plastic recycling development since the 1970s. It discusses the three common recycling options: mechanical recycling, chemical recycling, and energetic recycling. Additionally, it considers the challenges of waste cleaning and sorting. The article describes the mechanical and chemical recycling processes in detail for the main constituents of plastic waste, such as polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), and polyethylene terephthalate (PET). The current recycling rates indicate that only mechanical recycling is economically viable, which is insufficient for a sustainable circular economy. Chemical recycling methods are often too energy-intensive and require complex presorting making them unattractive. To become economically competitive, requirements for chemical recycling methods have been derived in this article. In this context, the splitting of polymer chains using low-temperature atmospheric pressure plasma is proposed as a novel technology. To date, this technology has only been used for the surface treatment of plastic. However, it shows the potential for processing unsorted, low-value plastic waste, especially PE, PP, and mixed waste, which would otherwise be sent for incineration or to landfills. Mechanical recycling is often unsuitable for these waste streams, and competitive chemical recycling methods are not yet established on an industrial scale.123
Fabrication Technique for Novel Nanocrystalline Cores with High Saturation Polarization and Low Losses
No full text15271532Nanocrystalline toroidal cores of the Nanomet alloy are produced by FAST/SPS. Flakes are prepared by milling starting from an amorphous ribbon. An oxidation layer is formed by heat treatment for electrical insulation between the flakes in the compacted toroid. A layer of sol gel is applied to further improve the insulation. The compacted toroidal cores have a density of about 80 %. Low losses of only 50 W/kg at 1 T and 1 kHz can be achieved by using a pressing aid
Monolithic Integrated Optic-Electronic-Optic Interferometer Transceiver PIC
No full textAn optic-electronic-optic (OEO) interferometer has an optically opaque processing arm where the signal is coherently detected, electronically processed and re-modulated. A monolithically integrated OEO PIC is presented. The PIC comprises a coherent photodetector, a tunable local oscillator and an IQ-Mach-Zehnder modulator
Hot-Starting Quantum Portfolio Optimization
No full text2333Combinatorial optimization with a smooth and convex objective function arises naturally in applications such as discrete mean-variance portfolio optimization, where assets must be traded in integer quantities. Although optimal solutions to the associated smooth problem can be computed efficiently, existing adiabatic quantum optimization methods cannot leverage this information. Moreover, while various warm-starting strategies have been proposed for gate-based quantum optimization, none of them explicitly integrate insights from the relaxed continuous solution into the QUBO formulation. In this work, a novel approach is introduced that restricts the search space to discrete solutions in the vicinity of the continuous optimum by constructing a compact Hilbert space, thereby reducing the number of required qubits. Experiments on software solvers and a D-Wave Advantage quantum annealer demonstrate that our method outperforms state-of-the-art techniques
Bridging Gaps, Building Futures: How DIREKTION Innovates for Global Disaster Resilience
No full textThe DIREKTION project, funded under Horizon Europe, aims to revolutionize disaster resilience through advanced technology and collaboration. Addressing the challenges posed by climate change, infrastructure vulnerabilities, and dynamic population densities, it seeks a paradigm shift in emergency responses. By integrating innovative technologies with the practical needs of responders and policymakers, DIREKTION enhances cross-sectoral harmonization and fosters stakeholder communication. Early outputs include drafts of the DIREKTION Assessment and Screening Framework and D-SAT tool, establishing a foundation for future development. The project's presentation at ISCRAM invites valuable feedback and engagement, highlighting its commitment to improving disaster management practices and fostering a more resilient society
Reliability of Automated RECIST 1.1 and Volumetric RECIST Target Lesion Response Evaluation in Follow-Up CT—A Multi-Center, Multi-Observer Reading Study
No full textObjectives: To evaluate the performance of a custom-made convolutional neural network (CNN) algorithm for fully automated lesion tracking and segmentation, as well as RECIST 1.1 evaluation, in longitudinal computed tomography (CT) studies compared to a manual Response Evaluation Criteria in Solid Tumors (RECIST 1.1) evaluation performed by three radiologists. Methods: Baseline and follow-up CTs of patients with stage IV melanoma (n = 58) was investigated in a retrospective reading study. Three radiologists performed manual measurements of metastatic lesions. Fully automated segmentations were generated, and diameters and volumes were computed from the segmentation results, with subsequent RECIST 1.1 evaluation. We measured (1) the intra- and inter-reader variability in the manual diameter measurements, (2) the agreement between manual and automated diameter measurements, as well as the resulting RECIST 1.1 categories, and (3) the agreement between the RECIST 1.1 categories derived from automated diameter measurement compared to automated volume measurements. Results: In total, 114 target lesions were measured at baseline and follow-up. The intraclass correlation coefficients (ICCs) for the intra- and inter-reader reliability of the diameter measurements were excellent, being >0.90 for all readers. There was moderate to almost perfect agreement when comparing the timepoint response category derived from the mean manual diameter measurements from all three readers with those derived from automated diameter measurements (Cohen’s k 0.67–0.76). The agreement between the manual and automated volumetric timepoint responses was substantial (Fleiss’ k 0.66–0.68) and that between the automated diameter and volume timepoint responses was substantial to almost perfect (Cohen’s k 0.81). Conclusions: The automated diameter measurement of preselected target lesions in follow-up CT is reliable and can potentially help to accelerate RECIST evaluation.162
Comparing IEC and WECC generic dynamic models for type 4 wind turbines
No full textTo ensure power system stability in the presence of a high penetration of power-electronic interfaced resources, Transmission System Operators (TSOs) require access to transparent, reliable and validated dynamic models to be able to conduct comprehensive large-scale studies. One possible approach is the utilization of so-called generic models that offer a modular structure capable of representing a wide range of installations by appropriately adjusting the parameters. This paper provides a thorough comparison of the two predominant generic models for Type 4 Wind Turbine (WT), developed by the International Electrotechnical Commission (IEC) and the Western Electric Coordinating Council (WECC), respectively. It highlights both the shared functionalities and the notable differences between these models, offering insights into their applicability. Furthermore, this analysis identifies unresolved questions regarding their implementation, emphasizing the need for further clarification to ensure a common understanding of their structure and consistent behavior across different tools.23
Fine Pitch Aluminum Hybrid Bonding: Overcoming the Challenges in Plating, Passivation and Bonding
No full textAluminium to Aluminium (Al-Al) direct bonding is CMOS line compatible and is comparable to gold (Au) and copper (Cu) due to metal cross-contamination in a process line. The Au-Au and Cu-Cu direct bonding are widely used and oxides of these metals are either negligible or can be controlled. Aluminium low temperature direct bonding would enable integrations of various types of sensors onto a CMOS wafer. On the contrary, Al tends to form an oxide layer as soon as it comes in contact to ambient atmosphere, which is difficult to remove and passivate thus requiring higher bonding temperature and bonding forces. In this paper, we would like to present the technology enabler processes that could lead to successful aluminium hybrid bonding: aluminum electro-plating for via filling, aluminum oxide removal and surface passivation and aluminium direct bonding at low temperatures. Low-temperature bonding is demonstrated using, in-situ surface treatment leading to metallic bonds at a temperature < 300 °C in ambient conditions
Extreme optical nonlinearities unveiled by ultrafast laser filamentation in semiconductors
No full textSky-high optical nonlinearities make semiconductors ideal platforms for multifunctional photonic devices. The fabrication of such complex devices could greatly benefit from in-volume ultrafast laser writing for monolithic and contactless integration. Ironically, as exemplified for Si, nonlinearities act as an efficient immune system that self-protects the material from internal permanent modifications. Predicting high-intensity ultrashort-pulse propagation beyond Si is further limited by incomplete descriptions of carrier dynamics in narrow-gap materials. Here, we demonstrate that filamentation universally dictates ultrashort laser pulse propagation in various semiconductors. The effective key nonlinear parameters extracted differ markedly from past measurements with low-intensity pulses, while temporal scaling laws for these parameters are also derived. Based on these findings, appropriate temporal-spectral shaping is proposed for tailored energy deposition inside semiconductors. The effective parameters also provide predictive inputs for semiconductor backside processing, microelectronics security, and high-harmonic, supercontinuum and terahertz wave generation.1