Staying on track:the road to elite performance in 1500m speed skating

Dutch elite speed skaters are world leading. This thesis provides scientific and practical insights in the development of 1500m Dutch speed skaters towards elite performance.Elite is therefore defined as skating within ten percent of the prevailing world record at a lowland ice rink. For all 63 female and 100 male skaters who reached the elite level between 1993 and 2013, performance development data from age thirteen to 26 years were obtained. Per age the average, maximal and minimal 1500m performance of the elite group was provided and compared with over 2500 competitive skaters who did not make it to the elite level. To make the results valuable for future generations, all performances are presented as a percentage of the prevailing world records.To explain performance development in speed skating, pacing (distribution of energy over the race), technique and muscle fatigue were studied. The research on pacing and technique included over 200 juniors (13-18 years) at the highest level in The Netherlands. Better performing juniors were better able to maintain velocity in the midsections of the race and showed better technique, characterized by lower knee and trunk angles. Additionally, pacing behavior is shown to change over time for junior speed skaters, with better performing juniors developing more towards the pacing behavior of elite speed skaters. On the short term, it appeared harder for speed skaters to change their pacing behavior. This is studied in comparison with cyclists, who were able to start more explosively when they were instructed to

The diffuse Nitsche method: Dirichlet constraints on phase-field boundaries

We explore diffuse formulations of Nitsche's method for consistently imposing Dirichlet boundary conditions on phase-field approximations of sharp domains. Leveraging the properties of the phase-field gradient, we derive the variational formulation of the diffuse Nitsche method by transferring all integrals associated with the Dirichlet boundary from a geometrically sharp surface format in the standard Nitsche method to a geometrically diffuse volumetric format. We also derive conditions for the stability of the discrete system and formulate a diffuse local eigenvalue problem, from which the stabilization parameter can be estimated automatically in each element. We advertise metastable phase-field solutions of the Allen-Cahn problem for transferring complex imaging data into diffuse geometric models. In particular, we discuss the use of mixed meshes, that is, an adaptively refined mesh for the phase-field in the diffuse boundary region and a uniform mesh for the representation of the physics-based solution fields. We illustrate accuracy and convergence properties of the diffuse Nitsche method and demonstrate its advantages over diffuse penalty-type methods. In the context of imaging based analysis, we show that the diffuse Nitsche method achieves the same accuracy as the standard Nitsche method with sharp surfaces, if the inherent length scales, i.e., the interface width of the phase-field, the voxel spacing and the mesh size, are properly related. We demonstrate the flexibility of the new method by analyzing stresses in a human vertebral body

Phase-field boundary conditions for the voxel finite cell method: surface-free stress analysis of CT-based bone structures

The voxel finite cell method employs unfitted finite element meshes and voxel quadrature rules to seamlessly transfer CT data into patient-specific bone discretizations. The method, however, still requires the explicit parametrization of boundary surfaces to impose traction and displacement boundary conditions, which constitutes a potential roadblock to automation. We explore a phase-field based formulation for imposing traction and displacement constraints in a diffuse sense. Its essential component is a diffuse geometry model generated from metastable phase-field solutions of the Allen-Cahn problem that assumes the imaging data as initial condition. Phase-field approximations of the boundary and its gradient are then employed to transfer all boundary terms in the variational formulation into volumetric terms. We show that in the context of the voxel finite cell method, diffuse boundary conditions achieve the same accuracy as boundary conditions defined over explicit sharp surfaces, if the inherent length scales, i.e., the interface width of the phase-field, the voxel spacing and the mesh size, are properly related. We demonstrate the flexibility of the new method by analyzing stresses in a human femur and a vertebral body

Improving sustainability through intelligent cargo and adaptive decision making

In the current society, logistics is faced with the challenge to meet more stringent sustainability goals. Shippers and transport service providers both aim to reduce the carbon footprint of their logistic operations. To do so, optimal use of logistics resources and physical infrastructure should be aimed for. An adaptive decision making process for the selection of a specific transport modality, transport provider and timeslot (aimed at minimisation of the carbon footprint) enables shippers to achieve this. This requires shippers to have access to up-to-date capacity information from transport providers (e.g. current and scheduled loading status of the various transport means and information on carbon footprint) and traffic information (e.g. city logistics and current traffic information). A prerequisite is an adequate infrastructure for collaboration and open exchange of information between the various stakeholders in the logistics value chain to obtain the up-to-date information. This paper gives a view on how such an advanced information infrastructure can be realised, currently being developed within the EU iCargo project. The paper describes a reference logistics value chain, including business benefits for each of the roles in the logistics value chain of aiming for sustainability. A case analysis is presented that reflects a practical situation in which the various roles collaborate and exchange information for realizing sustainability goals, using adaptive decision making for selecting a transport modality, transport provider, and timeslot. A high-level overview is provided of the requirements on and technical implementation of the supporting advanced infrastructure for collaboration and open information exchange.In the current society, logistics is faced with the challenge to meet more stringent sustainability goals. Shippers and transport service providers both aim to reduce the carbon footprint of their logistic operations. To do so, optimal use of logistics resources and physical infrastructure should be aimed for. An adaptive decision making process for the selection of a specific transport modality, transport provider and timeslot (aimed at minimisation of the carbon footprint) enables shippers to achieve this. This requires shippers to have access to up-to-date capacity information from transport providers (e.g. current and scheduled loading status of the various transport means and information on carbon footprint) and traffic information (e.g. city logistics and current traffic information). A prerequisite is an adequate infrastructure for collaboration and open exchange of information between the various stakeholders in the logistics value chain to obtain the up-to-date information. This paper gives a view on how such an advanced information infrastructure can be realised, currently being developed within the EU iCargo project. The paper describes a reference logistics value chain, including business benefits for each of the roles in the logistics value chain of aiming for sustainability. A case analysis is presented that reflects a practical situation in which the various roles collaborate and exchange information for realizing sustainability goals, using adaptive decision making for selecting a transport modality, transport provider, and timeslot. A high-level overview is provided of the requirements on and technical implementation of the supporting advanced infrastructure for collaboration and open information exchange.In the current society, logistics is faced with the challenge to meet more stringent sustainability goals. Shippers and transport service providers both aim to reduce the carbon footprint of their logistic operations. To do so, optimal use of logistics resources and physical infrastructure should be aimed for. An adaptive decision making process for the selection of a specific transport modality, transport provider and timeslot (aimed at minimisation of the carbon footprint) enables shippers to achieve this. This requires shippers to have access to up-to-date capacity information from transport providers (e.g. current and scheduled loading status of the various transport means and information on carbon footprint) and traffic information (e.g. city logistics and current traffic information). A prerequisite is an adequate infrastructure for collaboration and open exchange of information between the various stakeholders in the logistics value chain to obtain the up-to-date information. This paper gives a view on how such an advanced information infrastructure can be realised, currently being developed within the EU iCargo project. The paper describes a reference logistics value chain, including business benefits for each of the roles in the logistics value chain of aiming for sustainability. A case analysis is presented that reflects a practical situation in which the various roles collaborate and exchange information for realizing sustainability goals, using adaptive decision making for selecting a transport modality, transport provider, and timeslot. A high-level overview is provided of the requirements on and technical implementation of the supporting advanced infrastructure for collaboration and open information exchange

Context-aware prioritization of information: an architecture for real-time in-vehicle information management

Human Machine Interfaces (HMIs) are the communication devices between in-vehicle applications and the driver. Frequently, independent HMIs are used for different applications which may cause information overload situations at the driver. Hence, a common HMI design that determines the application interface with an HMI Manager that provides rules for prioritizing information from different applications is needed. The design takes into account: application transparency, driver situation awareness, driver workload and surrounding external influences. By reducing distraction, especially when the situation requires more attention of the driver, the need for controlling the information flow emerges. This paper presents a driver-centred unified approach for in-vehicle information managemen

Formalization and automatic interpretation of map requirements

The map requirements (constraints) can be interpreted by computer programs using their basic embedded functionalities. There are a huge number of constraints available to define the objective of various generalization outputs. Some of the constraints contain high-level knowledge which is not easy to interpret. This needs a huge amount of efforts to implement those constraints. The fact that many constraints have something in common makes the implementation per constraint a waste of resource. The paper proposes to decompose the constraints into more basic units, so as to interpret those constraints more flexible and reuse the already developed functionality as much as possible

Institutional Transplantation and the Rule of Law: How this Interdisciplinary Method can enhance the Legitimacy of International Organisations

Although the infl uence of various Western countries, especially that of the United States, is still substantial, the stars of China, India, Russia, Brazil and other large developing states are rising. Within international organisations this trend has become visible through a growing reluctance of non-Western states to accept and go along with the political, legal and economic diktats of European and American-fl avoured recipes and policies. This trend also has an impact on the compliance of international organisations with rule-of-law conceptions, which are not universal but depart from the cultural and national assumptions embraced mostly in Western countries. Even though the legality of international organisations may not be disputed as such in non-Western countries, the administrative and cultural acceptance of these organisations often remains questionable. This undermines the conception and the functioning of the rule of law at the international level. One of the ways in which acceptance of the rule of law can be enhanced at the international level is by utilising a method known as ‘institutional transplantation’. This method aims to facilitate new legal and policy initiatives through an adoption process in which the chances of achieving political and cultural congruence and desirability are maximised. After presenting the six principles underlying this approach, this article examines the case of the World Bank’s Inspection Panel, in order to show how these principles can be applied in practice