Tind Technologies (Norway)
Hes-so: ArODES Open Archive (University of Applied Sciences and Arts Western Switzerland / Haute école spécialisée de Suisse occidentale / FH Westschweiz)Not a member yet
15764 research outputs found
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Route to chaos in multi-species ecosystems
No full textWe investigate species-rich mathematical models of ecosystems. While much of the existing literature focuses on the properties of equilibrium fixed-points, persistent dynamics (e.g., limit cycles or chaos) have also been observed, both in natural or laboratory-controlled ecosystems and in mathematical models. Here, we emphasize the emergence of limit cycles following Hopf bifurcations tuned by the variability of interspecies interaction. As this variability increases and owing to the large dimensionality of the system, limit cycles typically acquire a growing spectrum of frequencies. This often leads to the appearance of strange attractors, with a chaotic dynamics of species abundances characterized by a positive Lyapunov exponent. We observe that limit cycles and strange attractors preserve biodiversity to some extent, as they maintain dynamical stability without species extinction. We give numerical evidences that this route to chaos dominates in ecosystems with strong enough interactions and where predator–prey behavior dominates over competition and mutualism. Based on arguments from random matrix theory, we further conjecture that this scenario is generic in ecosystems with a large number of species and identify the key parameters driving it. Overall, we show that the model we consider provides a unifying framework, where a wide range of population dynamics emerge from a simple few-parameter model
Is disability prevalence higher in rural areas ? ::evidence from functional difficulty and nightlight data in 15 low- and middle-income countries
No full textBackground : There has been emerging evidence from country-level studies that disability prevalence tends to be lower in urban areas than in rural areas. However, such studies are difficult to compare as countries use different ways of categorizing rural and urban areas. Objectives : We examine the association between disability measured through functional difficulties (seeing, hearing, walking, cognition, selfcare, communicating) and urban development measured through the satellite nightlight composite—an internationally comparable proxy for urban development. Methods : We use Demographic and Health Survey data for 15 low- and middle-income countries (LMICs) with the Washington Group Short Set of questions on disability. This study uses multilevel random intercept models to estimate whether functional difficulties are negatively associated with village-level nightlight composite. Results : While country level results vary, in the pooled sample, adults living in villages above the 80th percentile of nightlight activity have odds of reporting any functional difficulty that are 0.765 times those of adults in villages below the 80th percentile of nightlight (AOR = 0.765; 95 % CI = 0.717 to 0.816). The result is robust for each functional domain but the correlation is higher for hearing, cognition and communicating. Conclusions : In 15 LMICs, adults in rural areas are significantly more likely to have functional difficulties compared to adults in urban areas. Research is needed on the factors that drive such a correlation, including poorer living conditions and access to services in rural areas, differential access to resources and environmental barriers in rural and urban areas and potential differences in rural-urban migration opportunities across functional difficulty status
Double-Frame current control with a multivariable PI controller and power compensation for weak unbalanced networks
No full textThe handling of weak networks with asymmetric loads and disturbances im- plies the accurate handling of the second-harmonic component that appears in an unbalanced network. This paper proposes a classic vector control approach using a PI-based controller with superior decoupling capabilities for operation in weak networks with unbalanced phase voltages. A synchronization method for weak unbalanced networks is detailed, with dedicated dimensioning rules. The use of a double-frame controller allows a current symmetry or controlled imbalance to be forced for compensation of power oscillations by controlling the negative current sequence. This paper also serves as a useful reminder of the proper way to cancel the inherent coupling effect due to the transformation to the synchronous rotating reference frame, and of basic considerations of the relationship between switching frequency and control bandwidth
Power compensation approach and double frame control for grid connected converters
No full textThe handling of weak networks with asymmetric disturbances implies the accurate handling of the second harmonic component appearing under unbalanced networks. This paper proposes a two-step approach using classic vector control for operating the current controller from the network disturbance. First, both voltage and current must be described in the positive and negative sequence with a proper decoupling. The use of a double frame controller for forcing current balance proves to drastically reduce the second harmonic component in the DC-link voltage. As a second step, a current reference computing method is proposed for fully compensating power oscillations on the DC side that is applicable for phase voltage dips up to 50%
Potential for biogenic carbon storage towards a net-zero built environment in Switzerland
No full textThe built environment is a major contributor to global greenhouse gas (GHG) emissions, posing challenges for achieving net-zero targets by 2050. This study examines the potential of an increased use of biobased materials in the Swiss residential building stock to mitigate emissions while increasing biogenic carbon storage. Using a Python-based building stock model, the study evaluates the effectiveness of increasing the share of biobased materials in both renovations and new constructions under different scenarios compared to climate goals. Results indicate that renovations will become the dominant driver of building stock emissions and biogenic carbon storage potential by 2050. While new construction activities will decline due to demographic trends, renovations will contribute nearly four times more to GHG emissions than new buildings. Nevertheless, new constructions are more effective at storing biogenic carbon, achieving a biogenic-to-emissions ratio of 300 % by 2050, compared to 176 % for renovations. By mid-century, the yearly biogenic carbon storage in buildings could reach 2.5 Mt. CO₂, approaching a balance with yearly GHG embodied emissions. However, even in the most optimistic scenario, increasing biobased material use alone reduces cumulative emissions by only 5–8 % compared to business as usual, underscoring the need for additional emission reduction strategies, including decarbonizing material production and reducing construction activities. The long-term analysis reveals that biogenic carbon storage potential is constrained by demolition rates (assuming full re-emission at the end of life), with a higher demolition rate accelerating carbon turnover and limiting storage capacity. A cumulative maximum biogenic carbon stock of 300–400 Mt. CO₂ is projected in the long-term, surpassing Switzerland's expected cumulative net emissions removals by 2050 by 6 times. This study highlights the built environment's potential as a long-term carbon reservoir and emphasizes the necessity of targeted renovation strategies, regulatory policies, and material production improvements to achieve climate goals effectively
Über Mauern blicken - 25 Jahre Forschen im Justizvollzug ::Festschrift für Ueli Hostettler zum 65. Geburtstag
No full textThis publication marking the retirement of Ueli Hostettler brings together contributions from research and practice in the complex field of the penal system. The spectrum is diverse and includes contributions from legal and social science perspectives. In addition to the enforcement of adult criminal sentences and measures, the publication also addresses juvenile criminal law and the enforcement of juvenile sanctions, with a focus on Switzerland, Germany, and international comparisons. Topics such as punitive attitudes in society, quality and prison climate in the penal system, trends in prisoner numbers, reflections on empirical research, detention in juvenile criminal law, restorative justice, and social work in the penal system are discussed. In particular, the book provides insight into the important and fruitful cooperation between research and practice in Switzerland and the significance of the transfer of theory into practice for both sides
Exploring multiple levels of suffering and suicide prevention in an era of emerging national legislations
No full textAccess to assisted dying (variously called assisted suicide, euthanasia, and medical aid/assistance in dying) is increasingly available in many countries around the world. Individual suffering in the present and fears for the future, feature prominently in the request for assisted dying, which then affects many people beyond the identified individual, including family and loved ones, the clinical team associated with the dying process and societies. We consider expanding waves of distress, beginning with the subjective intrapsychic suffering of the individual requesting assistance in dying, the interpersonal effect on survivors, and the complex responses in those facing requests for assisted death. The autonomous rights of the individual to the alleviation of suffering are balanced by efforts toward suicide prevention, which are impacted when there are limited options to alleviate the psychosocial and existential suffering of those who express the wish to die
Herstellung von Mikrostrukturen über Glass Injection Molding ::Machbarkeitsgrenzen ausloten
No full textExperimental insights into the MW Range dual active bridge with silicon carbide devices
No full textAlongside the resonant topology of the Power Electronics Transformer, the Dual Active Bridge is one potential topology candidate for various LVDC and MVDC applications. For its study purpose, a 0.55 MW converter unit was built featuring the latest inhouse developed Medium Frequency Transformer operated by SiC LinPak semi-conductor devices. Main interest focusses on maximizing its efficiency in various operating points. The converter is experimentally demonstrated with two cells operated in back-to-back configuration
Grandeur Nature ::conférence performée
No full textGrandeur Nature est une conférence-performée jouée les 9 et 13 octobre 2024 à l’occasion de la Fête du Théâtre à Genève, par Mathias Brossard, Romain Daroles, Lara Khattabi et Loïc Le Manac’h. Elle présente, dans un format d’environ 1h, une mise en récit et en jeu des entretiens menés dans le cadre de la recherche « Jeu Grandeur Nature » en expérimentation, in situ, certains des résultats de cette recherche