Keuzestress!?

In de media en de sociologie wordt steeds vaker de indruk gewekt dat hedendaagse individuen aan stress en frustratie ten onder gaan vanwege hun schijnbaar onbeperkte keuzevrijheid. Maar is dat zo? Mensen blijken keuzestress bij hun alledaagse keuzes op drie manieren te ondervangen

Verspreiding inlaatwater in beeld met nieuwe tracer

Inlaatwater heeft in de polder Quarles van Ufford zelfs in een droge periode geen invloed op de waterkwaliteit van kleine landbouwsloten. Dat blijkt uit metingen van de concentratie gadolinium, die zijn uitgevoerd voor het project Monitoring Stroomgebieden. Hiermee komt voor dit gebied een einde aan de twijfel over de invloed van inlaatwater op de oppervlaktewaterkwaliteit en is er meer duidelijkheid over de belasting vanuit de landbouw

Adaptive to change? Compositional modelling of Healthcare Insurances using Protocol Modelling

This report presents the results of research on application of Protocol Modelling in the domain of healthcare insurance claims processing in the Dutch context. The conclusion of this study is that all necessary elements of flexibility for a healthcare insurance model, namely, flexibility in addition and removal of covered care procedures, flexibility in conditional coverage and flexible deductible, are supported by the protocol model by such means as Parameterization, User Exits, Composition, Derived Attributes and States. The first two options can also be achieved by other modelling techniques. The third option of CSP parallel composition leverages the composition semantics of Protocol Modelling. Composition, derived states and attributes enable the reuse of model elements

Biomechanical loads in running-based sports: estimating ground reaction forces from segmental accelerations

Training loads are monitored in sports as part of a process which aims to enhance performance whilst simultaneously reducing the risk of injury. Although physiological loads have been investigated extensively, biomechanical loading is still poorly quantified and, therefore, largely unexplored. Ground reaction force (GRF) is a well-established measure of external whole-body biomechanical loading, which drives and contributes to the internal stresses on e.g. muscles, tendons and bones. GRF might thus be used to further understand the relationship between whole-body biomechanical loads and performance and injuries, but valid methods for accurately estimating GRF outside laboratory settings are currently unavailable. However, since GRF is determined by the accelerations of the body’s different segments, currently popular body-worn accelerometers might allow for estimating GRF in the field. Therefore, the aim of this thesis was to investigate if GRF can be estimated from segmental accelerations, especially for dynamic and high-intensity running tasks that are frequently performed during running-based sports. The first two studies showed that a two mass-spring-damper model can be used to accurately reproduce overall GRF profiles and impulses for various high-intensity running tasks, but that this model cannot be used to predict GRF from trunk accelerometry. These results suggest that trunk accelerations alone are insufficient to accurately predict GRF in this manner, but additional information about accelerations of other segments allows for alternative approaches to be explored. Therefore, the third study aimed to estimate GRF from multiple segmental accelerations using a direct mechanical approach. GRF profiles from full-body segmental accelerations were estimated reasonably across dynamic and high-intensity running tasks, but errors substantially increased when the number of segments was reduced. Since these results further support the suggestion that one or several segmental accelerations are unlikely sufficient to estimate whole GRF waveforms, the fourth study aimed to identify key segmental contributions to distinct GRF features using principal component analysis. However, this study showed that dominant segmental acceleration characteristics and associated GRF features, as well as the relative importance of these features, are highly complex and task-specific. Together these findings show that it is unlikely that one or several segmental accelerations can provide accurate and meaningful estimates of GRF across different running activities. These outcomes warrant caution when using body-worn accelerometers to estimate GRF and monitor whole-body biomechanical loads during running-based sports in the field

Business Ownership and Unemployment in Japan

The influence of industrial structure, more specifically of business ownership, is investigated on the level of unemployment in Japan. The question is to what extent business ownership, i.e., entrepreneurship, can reduce the level of unemployment. It will be concluded that Japan is hardly an outlier when using a simple model of the relationship between unemployment and the rate of business ownership. The model is calibrated using recent data of 23 OECD countries. It shows a minor underestimation of the rise in unemployment in Japan in the period 1984-2002. Arguments are brought forward why this might be the case. We argue that small firms in Japan have benefitted in the past from the protective environment of the keiretsu structure. In the current process of industrial restructuring, keiretsu support is dissipating, but has not yet been adequatly replaced with a market environment conducive to the establishment and growth of entrepreneurial firms. The underestimation of the rise in unemployment is a reflection of the limited access of small firms to the market in Japan