Search results for "force"
showing 10 items of 3423 documents
Adaptive treatment of anemia on hemodialysis patients: A reinforcement learning approach
2011
The aim of this work is to study the applicability of reinforcement learning methods to design adaptive treatment strategies that optimize, in the long-term, the dosage of erythropoiesis-stimulating agents (ESAs) in the management of anemia in patients undergoing hemodialysis. Adaptive treatment strategies are recently emerging as a new paradigm for the treatment and long-term management of the chronic disease. Reinforcement Learning (RL) can be useful to extract such strategies from clinical data, taking into account delayed effects and without requiring any mathematical model. In this work, we focus on the so-called Fitted Q Iteration algorithm, a RL approach that deals with the data very…
On stiffness and damping of vibro-impact dynamics of backlash
2021
We consider the instantaneous stiffness and damping of the vibro-impact in a backlash pair. Opposed to the existing and mostly used models of the backlash, we address the problem of contact and separation, and the associated force propagation within a mechanical pair, from a viewpoint of the vibro-impact dynamics. We discuss the impact forces with the coefficient of restitution as a principal factor which shapes the transient backlash response.We show that a common approach to modeling the backlash by means of a dead-zone in a restoring force is unsuitable for correctly capturing the mechanical impact. We exemplary demonstrate a qualitative accord between an experimental backlash response a…
A Comparative Analysis of Multiple Biasing Techniques for $Q_{biased}$ Softmax Regression Algorithm
2021
Over the past many years the popularity of robotic workers has seen a tremendous surge. Several tasks which were previously considered insurmountable are able to be performed by robots efficiently, with much ease. This is mainly due to the advances made in the field of control systems and artificial intelligence in recent years. Lately, we have seen Reinforcement Learning (RL) capture the spotlight, in the field of robotics. Instead of explicitly specifying the solution of a particular task, RL enables the robot (agent) to explore its environment and through trial and error choose the appropriate response. In this paper, a comparative analysis of biasing techniques for the Q-biased softmax …
Economic Diversification and Empowerment of Local Human Resources: Could Singapore Be a Model for the GCC Countries?
2018
This chapter analyses the similarities and differences between the GCC and Singapore with regard to economic diversification strategies. The key for a successful and, thus, sustainable diversification process for the GCC is to reduce the high dependence of the economic revenues away from the hydrocarbon sector. However, an ongoing concern is the continuing need of high foreign workforce that collides with the demands for greater employment opportunities for national citizens. The challenges of those nationalisation strategies will be examined at the example of the Sultanate of Oman.
Safety Related Behaviors and Law Adherence of Shared E-Scooter Riders in Germany
2021
Shared e-scooters, whose supply and coverage keeps increasing in many cities around the globe, are rapidly changing mobility in urban road environments. As rising injury rates have been observed alongside this new form of mobility, researchers are investigating potential factors that relate to safe/unsafe e-scooter use. In Germany, e-scooter sharing platforms were only recently permitted in the middle of 2019, and their number has increased steadily since then. The aim of this study was to assess key factors that relate to their safe use, through a direct observation of e-scooters conducted at three observation sites around Berlin. Helmet use, dual use, type of infrastructure use, and trave…
Validation of a Reinforcement Learning Policy for Dosage Optimization of Erythropoietin
2007
This paper deals with the validation of a Reinforcement Learning (RL) policy for dosage optimization of Erythropoietin (EPO). This policy was obtained using data from patients in a haemodialysis program during the year 2005. The goal of this policy was to maintain patients' Haemoglobin (Hb) level between 11.5 g/dl and 12.5 g/dl. An individual management was needed, as each patient usually presents a different response to the treatment. RL provides an attractive and satisfactory solution, showing that a policy based on RL would be much more successful in achieving the goal of maintaining patients within the desired target of Hb than the policy followed by the hospital so far. In this work, t…
Internal oblique line implants in severe mandibular atrophies
2020
Background Maxillary atrophy may be related to mechanical, inflammatory or systemic factors, being a consequence of a reduction in the amount and quality of available bone. Several surgical techniques have been developed for the restoration of bone volume needed for placing dental implants; guided bone regeneration or three-dimensional reconstructions with autologous bone, inter alia, are techniques described in the literature which demonstrate this, all of which preceded by a proper prosthetic surgical assessment. Even when the majority of authors recommend the use of these techniques prior to placing implants, it has been shown that implants with a smaller diameter and length may be place…
770 A comparative european analysis of the link between work stressors and worker outcomes
2018
Introduction Given the changing nature of employment, including the long term shift from manufacturing and agriculture to the service sector, an increasing proportion of the workforce is engaged in employment which is less physically demanding but which brings with it a range of stress-related and psycho-social risks. Eurofound (2006) estimated that in 2005, 20% of EU-15 workers reported health related risk due to work-related stress and the EU OSHA (2007) has identified high emotional demands and work intensification as key emerging psychosocial risks for the occupational health and safety of workers. Methods This paper draws on the 2015 European Working Conditions Survey to examine differ…
Frequency composition of traction and tillage forces on a mole plough
1997
Field experiments were carried out in order to quantify the variations of the traction and tillage forces on a mole plough, in the case of four clayey soils of Eastern France. The same tractor-implement system, the same forward working speed (1 m s−1) and the same length of ploughing (20 m) were used. Specially designed strain gauge transducers applied to the system delivered a signal which was numerised and analysed in terms of power spectral density (PSD) function. The frequency composition of the traction and tillage forces consisted of interactions between soil and tool as well as vibrations of the tractor-implement system. Low frequencies (0–2 Hz range) were related to the random prope…
Helical Shift Mechanics of Rubber V-Belt Variators
2011
A very common configuration of V-belt variators for motorcycles considers the correction of the belt tensioning depending on the resistant torque by means of suitable helical-shaped tracks allowing the driven half-pulleys to close/open. The theoretical model for belt-pulley coupling is rather complex for this configuration, where one half-pulley may run in advance and the other one behind with respect to the belt, and requires the repeated numerical solution of a strongly nonlinear differential system by a sort of shooting technique, until all the operating conditions are fulfilled (angular contact extent, torque, and axial force). After solving the full equations, the present study develop…