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L.W. te Hennepe
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Problem: Camera-based vital sign monitoring offers an additional safety layer to general wards, but developing and validating such systems requires representative datasets of human respiration patterns. Current approaches rely on costly and time-consuming recruitment of human participants, limiting algorithmic development and benchmarking. A linear mechanical respiration simulator could reduce this burden, but only if it produces respiration patterns that the optical flow algorithm detects the same way it detects real human breathing. Methods: A respiration simulator was constructed and validated to faithfully reproduce human respiration patterns derived from a respiratory belt. A dataset of eight subjects was used across three scenarios where the subjects were lying still. Optical flow was extracted from videos of both the human subject and the respiration simulator performing the same respiration pattern using the Farneback optical flow algorithm. Correlations between human and simulator optical flow were evaluated separately for each scenario using Fisher's z-transformation and one-sample t-tests. Results: Equivalence between detected movement by the optical flow for the human subject and respiration simulator was confirmed across all three scenarios, with mean r-values of 0.938 (95% CI: [0.895, 0.963]), 0.916 (95% CI: [0.845, 0.955]), and 0.935 (95% CI: [0.885, 0.964]), all significantly different from zero (p < 0.001). The respiration simulator reproduced respiration belt input signals with high fidelity (range: 0.895-0.995), and optical flow tracking of simulator movement was robust across physiological amplitudes and frequencies (r > 0.952). Conclusions: A simple linear mechanical simulator can replicate human respiratory motion in a manner equivalently detectable by optical flow algorithms. This validates the use of such a simulator as a controllable, repeatable alternative to human participants for developing, training, and benchmarking camera-based respiratory monitoring systems.
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Problem: Camera-based vital sign monitoring offers an additional safety layer to general wards, but developing and validating such systems requires representative datasets of human respiration patterns. Current approaches rely on costly and time-consuming recruitment of human participants, limiting algorithmic development and benchmarking. A linear mechanical respiration simulator could reduce this burden, but only if it produces respiration patterns that the optical flow algorithm detects the same way it detects real human breathing. Methods: A respiration simulator was constructed and validated to faithfully reproduce human respiration patterns derived from a respiratory belt. A dataset of eight subjects was used across three scenarios where the subjects were lying still. Optical flow was extracted from videos of both the human subject and the respiration simulator performing the same respiration pattern using the Farneback optical flow algorithm. Correlations between human and simulator optical flow were evaluated separately for each scenario using Fisher's z-transformation and one-sample t-tests. Results: Equivalence between detected movement by the optical flow for the human subject and respiration simulator was confirmed across all three scenarios, with mean r-values of 0.938 (95% CI: [0.895, 0.963]), 0.916 (95% CI: [0.845, 0.955]), and 0.935 (95% CI: [0.885, 0.964]), all significantly different from zero (p < 0.001). The respiration simulator reproduced respiration belt input signals with high fidelity (range: 0.895-0.995), and optical flow tracking of simulator movement was robust across physiological amplitudes and frequencies (r > 0.952). Conclusions: A simple linear mechanical simulator can replicate human respiratory motion in a manner equivalently detectable by optical flow algorithms. This validates the use of such a simulator as a controllable, repeatable alternative to human participants for developing, training, and benchmarking camera-based respiratory monitoring systems.
Coastal Erosion in the Progreso Area
Mapping the technical and social context to work towards a sustainable solution
Student report
(2025)
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S.C.L. van Etten, G.A. van Grieken, L.W. te Hennepe, X.C. Hubbelmeijer, V. van Spronsen, S.H.E. van der Velde, José A. Á. Antolínez, Alec Torres Freyermuth, Wilmer Rey
Coastal erosion has caused beach loss and threatens first-row beachfront houses and other nearshore structures in Progreso, Yucatán (Mexico). This multidisciplinary project combines shoreline analysis, social research and stakeholder mapping to develop an integrated understanding of coastal erosion, its effects and the socio-environmental context in the study area. The aim is to translate this knowledge into a coordinated and sustainable approach that promotes coastal resilience.
The shoreline analysis that was performed using satellite imagery showed evidence of both accretion and erosion in the study area. A forecast of the coastline retreat showed that in the western part of the Progreso area, the number of properties that lie within 10 meters of the shoreline is expected to double within the next decade.
The findings of the social analysis and stakeholder mapping revealed a communication and knowledge gap. The communication gap occurs between neighbours, so among coastal homeowners, but also between them and the governmental institutions. There is a knowledge gap due to the need for knowledge sharing among coastal homeowners.
A solution for the coastal erosion problem in the Progreso area is only possible by first implementing a social strategy; otherwise, no physical measure will be effective. Thus, the coastal community committee (CCC) is proposed to address the identified communication and knowledge gaps, as well as the fragmented responsibilities. The CCC is a group that makes decisions about measures to improve coastal resilience and engages local residents and stakeholders. In order to physically reconstruct a resilient coast, the use of a Sandsaver is proposed for sand accretion. To achieve long-term coastal resilience, dune formation is necessary. The report includes a plan for testing this Sandsaver and also a plan for implementing the CCC. ...
The shoreline analysis that was performed using satellite imagery showed evidence of both accretion and erosion in the study area. A forecast of the coastline retreat showed that in the western part of the Progreso area, the number of properties that lie within 10 meters of the shoreline is expected to double within the next decade.
The findings of the social analysis and stakeholder mapping revealed a communication and knowledge gap. The communication gap occurs between neighbours, so among coastal homeowners, but also between them and the governmental institutions. There is a knowledge gap due to the need for knowledge sharing among coastal homeowners.
A solution for the coastal erosion problem in the Progreso area is only possible by first implementing a social strategy; otherwise, no physical measure will be effective. Thus, the coastal community committee (CCC) is proposed to address the identified communication and knowledge gaps, as well as the fragmented responsibilities. The CCC is a group that makes decisions about measures to improve coastal resilience and engages local residents and stakeholders. In order to physically reconstruct a resilient coast, the use of a Sandsaver is proposed for sand accretion. To achieve long-term coastal resilience, dune formation is necessary. The report includes a plan for testing this Sandsaver and also a plan for implementing the CCC. ...
Coastal erosion has caused beach loss and threatens first-row beachfront houses and other nearshore structures in Progreso, Yucatán (Mexico). This multidisciplinary project combines shoreline analysis, social research and stakeholder mapping to develop an integrated understanding of coastal erosion, its effects and the socio-environmental context in the study area. The aim is to translate this knowledge into a coordinated and sustainable approach that promotes coastal resilience.
The shoreline analysis that was performed using satellite imagery showed evidence of both accretion and erosion in the study area. A forecast of the coastline retreat showed that in the western part of the Progreso area, the number of properties that lie within 10 meters of the shoreline is expected to double within the next decade.
The findings of the social analysis and stakeholder mapping revealed a communication and knowledge gap. The communication gap occurs between neighbours, so among coastal homeowners, but also between them and the governmental institutions. There is a knowledge gap due to the need for knowledge sharing among coastal homeowners.
A solution for the coastal erosion problem in the Progreso area is only possible by first implementing a social strategy; otherwise, no physical measure will be effective. Thus, the coastal community committee (CCC) is proposed to address the identified communication and knowledge gaps, as well as the fragmented responsibilities. The CCC is a group that makes decisions about measures to improve coastal resilience and engages local residents and stakeholders. In order to physically reconstruct a resilient coast, the use of a Sandsaver is proposed for sand accretion. To achieve long-term coastal resilience, dune formation is necessary. The report includes a plan for testing this Sandsaver and also a plan for implementing the CCC.
The shoreline analysis that was performed using satellite imagery showed evidence of both accretion and erosion in the study area. A forecast of the coastline retreat showed that in the western part of the Progreso area, the number of properties that lie within 10 meters of the shoreline is expected to double within the next decade.
The findings of the social analysis and stakeholder mapping revealed a communication and knowledge gap. The communication gap occurs between neighbours, so among coastal homeowners, but also between them and the governmental institutions. There is a knowledge gap due to the need for knowledge sharing among coastal homeowners.
A solution for the coastal erosion problem in the Progreso area is only possible by first implementing a social strategy; otherwise, no physical measure will be effective. Thus, the coastal community committee (CCC) is proposed to address the identified communication and knowledge gaps, as well as the fragmented responsibilities. The CCC is a group that makes decisions about measures to improve coastal resilience and engages local residents and stakeholders. In order to physically reconstruct a resilient coast, the use of a Sandsaver is proposed for sand accretion. To achieve long-term coastal resilience, dune formation is necessary. The report includes a plan for testing this Sandsaver and also a plan for implementing the CCC.