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Optimal Design of Fixed and Variable Costs in Peer-to-Peer Insurance with Heterogeneous Risk
No full textThis paper examines the optimal design of peer-to-peer insurance models, which
combines outside insurance purchases with peer-to-peer risk sharing and heteroge neous risk. Participants contribute deposits to collectively cover the premium for
group-based insurance against tail risks and to share uncovered losses. We analyze
the cost structure by decomposing it into a fixed premium for outside coverage and a
variable component for shared losses, the latter of which may be partially refunded if
aggregate losses are sufficiently low. We derive closed-form solutions to the optimal
sharing rule that maximizes a mean-variance objective from the perspective of a
central or social planner, and we characterize its theoretical properties. Building on
this foundation, we further investigate the choice of deposit for the common fund.
Finally, we also provide numerical illustrations.status: Accepte
Unraveling Perceived Work Values of Role Models From TV Series and Social Media in Adolescents’ Work Value Endorsement: A Longitudinal Investigation
No full textsponsorship: The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Research Foundation Flanders (FWO-Vlaanderen) under Grant 11G0220N. (Research Foundation Flanders (FWO-Vlaanderen)|11G0220N)status: Published onlin
Solidariteit in aanwinstenstelsels
No full textUpon entering into a marriage, the spouses' patrimonial situations are governed by a matrimonial property regime. Each regime established a distinctive degree of patrimonial solidarity between the spouses. Pure separation of property regimes aim to achieve a low degree of solidarity, while universal community property regimes exhibit a high degree of solidarity. Nevertheless, other regimes offer spouses a more balanced and fair degree of solidarity, that expresses the concept of marriage as a partnership between them. This is particularly the case for regimes that distribute the assets the spouses have obtained non-gratuitously during the marriage in a more or less equal manner upon divorce. Regimes that adhere to this characteristic may be classified as 'acquisitions regimes'. Nevertheless, these acquisitions regimes form a heterogeneous group. Both community regimes, which establish a community property from the outset of the marriage, and participation regimes, which adhere to a separation of property during the marriage, can achieve an equal distribution of the acquisitions. In light of the above, the question arises as to how solidarity is expressed in these acquisitions regimes' more detailed patrimonial operations.
To address this question, a comprehensive analysis has been conducted of ten different matrimonial property regimes from seven different jurisdictions (Austria, Belgium, France, Germany, the Netherlands, Norway, and Switzerland), as well as the matrimonial property regimes as proposed by the Commission on European Family Law and the Franco-German Agreement of 2010. These thirteen regimes have been subjected to a functional comparative analysis on the basis of ten parameters in order to assess how solidarity is precisely expressed. These parameters include, among others, the administration of assets, the protection of the family home, the debt regulation, the content of the distributable mass, the key of distribution, and the possibility of contractual deviations from the statutory regulation.
This research has resulted in an in-depth evaluation of thirteen European acquisitions regimes. Based on this evaluation, punctual recommendations for each regime have been formulated, as well as global best practices that may guide legislative reforms or marital contracts. In general, the research findings indicate that the distinctions between community regimes and participation regimes are not always as straightforward as they may initially appear. With regard to a number of aspects, both types of matrimonial property regimes display similar characteristics and comparable solutions. Furthermore, it is contended that community regimes do not always express a higher degree of solidarity in comparison with participation regimes when considering their detailed operations. These novel insights facilitate a more transparent understanding and a critical assessment of solidarity in acquisitions regimes.status: Publishe
Een fysiologische benadering voor het monitoren van chronische pijn aan de hand van draagbare sensoren
No full textChronic pain is pain which lasts or reoccurs for at least three months. Besides affecting the quality of life of individuals, it impacts society by contributing to increased healthcare costs and early labour market exit. Many patients with chronic pain do not receive adequate pain management. To enhance pain management, accurate assessment of pain is crucial to select appropriate treatment, monitor progress, and evaluate recovery. Pain is usually assessed verbally, making it susceptible to recall bias. While research has demonstrated that physiological signals can distinguish between pain and no pain in controlled settings, the application in real-world settings or clinical populations remains limited.
In this work, we investigated the potential of physiological signals, captured with a wearable wristband, for monitoring pain in daily life among patients with chronic widespread pain. For this, three objectives were defined: 1) improving the accuracy of ambulatory skin conductance derived variables, 2) identifying physiological biomarkers relevant for momentary ambulatory chronic pain monitoring, and 3) identifying distinct stress-induced psychophysiological response profiles.
Collecting physiological signals in daily life is challenging, with low-quality and missing data often present due to motion or contextual influences. We investigated if we could improve the accuracy of skin conductance derived variables. For this, we quantitatively compared the accuracy of several open-source algorithms for detecting low-quality segments and responses in the skin conductance signal against manual labels. We demonstrated that algorithms should be retrained for every new set-up and device. Moreover, we quantitatively compared three methods for handling low-quality segments based on the accuracy of skin conductance derived variables. This analysis resulted in three processing guidelines which were implemented throughout the rest of the work.
We aimed to identify physiological biomarkers that are associated with momentary pain. For this, we investigated the associations between physiological signals obtained in daily life settings, with momentary pain, prompted on the participants smartphone at multiple times per day. The group level analyses which used hierarchical linear regression models revealed significant associations between momentary pain and several physiological variables, including mean heart rate (p=0.001) and mean skin temperature slope per minute (p=0.02). However, adding these physiological variables into pain prediction models for unseen participants did not significantly improve the accuracy.
Stress likely plays a role in the pathophysiology of chronic widespread pain. Therefore, we investigated whether subgroups of patients with a similar physiological stress response profile could be identified and whether these subgroups were linked to the severity of pain-related symptoms. While no multiple multivariate psychophysiological stress response profiles (perceived stress, pain, cortisol, and physiology) were identified, two physiological stress response profiles (cortisol and cardiac measures), and three univariate cortisol response profiles were identified for patients. Despite this, no significant associations between these profiles and most pain-related symptoms (affect, catastrophizing, pain task derived measures, pain intensity in daily life, and physiology in daily life) were found. These findings suggested a dissociation between psychological and physiological measures at the individual level. Additionally, they highlighted the complex interplay between the physiological stress responses and potential underlying pathophysiological mechanisms.
In conclusion, we showed the potential of physiological variables for assessing momentary pain at group level. However, using physiological measures to predict pain or distinguish clinically relevant subgroups remained challenging because of the complexity and multidimensionality of chronic pain. Future large-scale longitudinal studies comprising multiple sensing modalities and using personalized models are needed to gain further understanding of the role of physiological signals in pain assessment and treatment.status: Publishe
Het zwijgrecht van vennootschappen
No full textThe research topic of this doctoral dissertation is the privilege against self-incrimination of corporations. The issue is highly relevant in view of the importance of corporations in society and the increasing use of corporate criminal liability. The research and theory on the substantive criteria of the criminal responsibility of corporations is not paralleled by corresponding research into the fair trial rights of corporations as criminal defendants.
Therefore this doctoral dissertation aims at providing a thorough analysis of the privilege against self-incrimination of corporations. The research is conducted along two lines: on the one hand, the dissertation analyses the origin, ratio and scope of the privilege against self-incrimination from a European perspective as well as from the perspective of three selected national systems (Belgium, England and Wales and the United States of America). On the other hand, it encompasses both theoretical and practical considerations.
The central research question that is addressed throughout the research is: Does the privilege against self-incrimination apply to corporations, should it apply to corporations, and if so, to what extent? The research provides a tentative framework for the privilege against self-incrimination of corporations, and indicates whether and how it should apply to corporations. In doing so, the dissertation wants to make a meaningful contribution to the more general debate on the entitlement of corporations to fair trial rights.status: Publishe
Lignine als basis voor geavanceerde vloeibare biobrandstoffen voor de luchtvaart
No full textDecarbonizing aviation remains one of the hardest challenges in the global energy transition, as the sector depends almost entirely on fossil-based fuels whose exceptional energy density and physicochemical properties are difficult to replicate with alternative energy carriers. To meet the European Union's climate neutrality objectives, the ReFuelEU Aviation Regulation mandates that 70% of aviation fuel be replaced by sustainable aviation fuel (SAF) by 2050. However, current SAF production is limited, as only a few ASTM-approved and mature processes exist—restricting the large-scale production of SAF. The approved routes mainly yield linear hydrocarbons (iso- and n-alkanes), leaving a deficit of cyclic components—naphthenes and aromatics—that are essential for reproducing the energy density and functional properties of conventional jet fuels.
In this context, lignocellulosic biomass (LCB), and particularly its lignin fraction, represents a promising renewable feedstock to supply these cyclic hydrocarbons. Lignin is the largest natural source of aromatics on Earth; however, its high oxygen content makes it unsuitable as a drop-in fuel. To overcome this, its oxygen content can be effectively reduced through hydrodeoxygenation (HDO), a catalytic process that removes oxygen from lignin-derived methoxy phenols, yielding cyclic hydrocarbons within the jet-fuel range.
This thesis advances the understanding of the lignin-to-SAF pathway across three complementary dimensions: feedstock availability, feedstock quality, and molecular-level reactivity.
First, an assessment of European lignin availability demonstrated that the amount of LCB potentially harvestable under sustainable conditions could deliver the quantity of lignin necessary to meet future SAF demand. However, to achieve this sustainably, the gradual introduction of lignin-first valorization strategies into existing lignocellulosic biorefining pathways is essential. Among these, Reductive Catalytic Fractionation (RCF) emerges as a particularly promising approach, capable of producing around 20 Mt C per year of lignin oil—equivalent to approximately 30 Mt per year—sufficient to supply the targeted amount under the ReFuelEU Aviation Regulation of 5.6 Mt per year of aromatics and 10.2 Mt per year of naphthenes after HDO.
Second, the thesis investigates the relationship between the physicochemical properties of lignin oil and HDO performance. Using various lignin oils upgraded over a phosphidated Ni/SiO2 catalyst, it was shown that RCF-derived oils, prepared from eucalyptus, poplar, and pine using Ru/C as the biorefining catalyst, significantly outperform both conventional technical lignins and RCF-derived lignin oils produced using Pd/C. The superior performance of Ru/C-derived lignin oils was attributed to their lower molecular weight compared to technical lignins—resulting in higher solubility in the alkane medium used for HDO—and to their lower γ-OH end-unit content compared to RCF-derived lignin with Pd/C as catalyst. A direct correlation between the γ-OH content, determined by 1H-13C HSQC NMR, and the selectivity toward jet-range hydrocarbons after HDO was established. Lignin oils with a lower γ-OH content, characteristic of those obtained from Ru/C-catalyzed RCF, exhibited markedly higher selectivity toward SAF-range naphthenes than Pd/C-derived oils. In contrast, the feedstock type (hardwood vs. softwood) had minimal influence, confirming that the biorefining catalyst and strategy are the key parameters governing jet-range hydrocarbon yields and selectivity.
Finally, a fractionation-guided molecular investigation provided mechanistic insight into the conversion of RCF-derived lignin oils into SAF-range hydrocarbons. Lignin oil obtained from pine via Ru/C-catalyzed RCF was separated into six fractions (H100-E100) using solvent polarity-based extraction with n-heptane and ethyl acetate. Each fraction was comprehensively characterized by GPC, GCxGC-MS/FID, and 1H-13C HSQC NMR, and subsequently upgraded via HDO using phosphidated Ni/SiO2 at 300 °C and 50 bar H2 in dodecane. Early fractions (H100-H40) proved highly effective in producing C8-C18 naphthenic hydrocarbons, exhibiting a relative carbon yield (RCY) sequence of H100 > H80 > H60 > H40 (74%, 55.4%, 52%, 35.4%). The H100 fraction delivered predominantly monomer-derived mono-naphthenes, particularly propyl-cyclohexane (54 % RCY), while the heavier fractions (H80-H60) produced bi-naphthenes such as C14-C18 species, with C17 bi-naphthenes being the most abundant (17 % RCY in H60). These results demonstrate that monomer- and dimer-rich fractions are the most suitable for SAF production, whereas oligomeric fractions are poorly converted under HDO but may serve as valuable co-products for other applications—such as polymeric materials.
Overall, this work establishes lignin as a viable renewable source of cyclic hydrocarbons for sustainable aviation fuel production. By integrating feedstock availability analysis, structure-property-performance relationships, and molecular-level transformation pathways, this thesis defines a technically grounded route toward scalable lignin-derived SAF aligned with European decarbonization targets.status: Publishe
Optimalisatie methodologieën voor modellen van tweefase loopsystemen met toepassingen in elektronicakoeling
No full textIn this work, a physics-based one-dimensional numerical model is proposed to evaluate the performance of passively cooled loop heat pipe (LHP) systems and their operational limits. An in-house setup was built, consisting of an entirely passive LHP with a flat evaporator (1 cm^2) active area) with accurate temperature measurements. Transparent materials are used to facilitate observations. With careful assessment of input power and calibration of heat transfer coefficients for the condenser, the model is validated by comparing the local temperatures in the evaporator and compensation chamber, the two-phase flow lengths in the condenser, and by evaluating the energy balance. The relative discrepancy between predicted and measured operating temperatures remains below 3.5% across all test cases.
The validated model is then used to predict the system performance for the experimental setup with low thermal-conductivity casing, examining the effects of varying the coolant charging mass on various operational limits. The numerical results indicate that the LHP studied operates exclusively in fixed conductance mode. At 50% charging ratio, the system achieves the lowest operating temperature. The naturally cooled condenser and compensation chamber can dissipate over 29.9 W when the coolant saturation temperature reaches 100\celsius.
As the heat leakage rate from the evaporator to the coolant in the compensation chamber is low, the analysis of the operational limits shows that, for the current LHP and operating conditions, the heat dissipation limit restricts the maximum input power and activates the heat leakage limit. In addition, the heat dissipation capacity and thermal resistance of the condenser are the primary limitations of the operational envelope.
The model is further refined to account for more realistic casing material, and is then used to investigate the influence of various design parameters. When a metallic casing is employed, the heat leakage is significantly amplified, with the casing becoming the dominant pathway for heat leakage from the evaporator to the compensation chamber. This results in a pronounced nonlinear segment in all performance curves --corresponding to variable conductance mode-- across various coolant charging masses. For the LHPs studied with copper casing, this variable conductance mode even becomes the dominant operating mode. In this mode, for identical operating conditions and charging mass, the system exhibits a higher operating temperature. The impact of coolant charging mass on the system performance becomes negligible.
Reducing the casing thickness, improving the contact at the wick-fin interface, or using low thermal conductive casing material can mitigate the heat leakage and lower the operating temperature. However, material substitution can also lead to extremely high junction temperatures, which may compromise the system reliability.
Finally, analysis on the operational envelopes and limits shows that the use of a metallic casing can readily activate the heat leakage limit to the compensation chamber and, at high input powers, the heat leakage limit to the wick --while not triggering the heat dissipation limit. Under these conditions, variations in condenser geometries or cooling intensities have only a minor influence on the LHP performance and its operational envelope. The results indicate that reducing heat leakage through the casing and improving overall system cooling capacity must be addressed in tandem in the LHP design to achieve optimal performance.status: Publishe
Collocational profiles and semantic properties of quantifying nouns in Polish (with the meaning ‘many x-s’)
No full textThis paper examines the collocational profiles of eleven quantifying nouns in Polish: góra ‘mountain’, lawina ‘avalanche’, nawał ‘load’, huk ‘bang’, grad ‘hail’, deszcz ‘rain’, burza ‘storm’, chmura ‘cloud’, las ‘forest’, sznur ‘rope’, and warkocz ‘braid’. The analysis of their more and less frequent collocates is combined with a brief analysis of lexicographic descriptions of these items, focusing on the way their quantifying uses are presented in older and modern Polish dictionaries. An overview of their present-day uses shows how quantifying meanings build on primary meanings. In some cases, such as lawina ‘avalanche’, broadening the collocational range facilitates actional traits, with temporal sequentiality mapped onto the primary meaning of these lexical items via metaphorization. The author argues in favour of the semantic generalisation of quantifying uses for most discussed items (with the exception of las ‘forest’), while also providing arguments for their non-synonymity.status: Accepte
Radiobronnenplanning voor celvrije massieve MIMO in post-5G-netwerken
No full textTo meet diverse requirements of future communication systems, beyond 5G intelligent networks will provide enhanced flexibility through the dynamic scheduling of the available resources. Given the densification of networks, and the introduction of cell-free Massive MIMO architectures, the availability of radio access resources is unseen, and is only limited by the potential of the resource allocation methods. A major challenge is how to achieve this within standard and open architectures, such as for instance the O-RAN alliance. In this PhD, the goal is to conceive an architecture for cell-free Massive MIMO compatible with the O-RAN concept. In addition, scheduling algorithms for energy-efficiency, reliability and delay using data-driven methods will be proposed.status: Accepte