56 research outputs found
Distributed supply chain simulation in GRIDS
No full textAmongst the majority of work done in supply chain simulation, papers have emerged that examine the area of model distribution. The executions of simulations on distributed hosts as a coupled model require both coordination and facilitating infrastructure. A distributed environment, the Generic Runtime Infrastructure for Distributed Simulation (GRIDS) is suggested to provide the bonding requirements for such a model. The advantages of transparently connecting the distributed components of a supply chain simulation allow the construction of a conceptual simulation while releasing the modeler from the complexities of the underlying network. The infrastructure presented demonstrates scalability without losing flexibility for future extensions based on open industry standard
The duration-dependent effect of skin temperature on self-pacing cycling exercise
Get PDFSkin temperature has been suggested as a relevant physiological signal for the anticipatory and feedback control of work rate during self-paced exercise [1, 2]. However, a sudden extreme skin temperature elevation did not affect pacing during a 7.5-km cycling time trial [3]. Possible explanations for the discrepancy in these results are the duration of the self-paced exercise and the length of the skin temperature manipulations. To investigate whether the duration of the manipulation in skin temperature, or the duration of the time trial is more relevant for the influence of an elevated skin temperature on pacing pattern and performance during aerobic exercise, we investigated the effect of two different lengths of radiative heat exposure on pacing pattern during a 15-km cycling time trial. Together with results from our previous study [3], in which an identical intervention was applied during a cycling time trial of 7.5 km, conclusions can be drawn about the relative importance of time trial duration and the duration of the manipulation
The effect of global warming and urban heat islands on mortality, morbidity and productivity in The Netherlands
Get PDFAutomatic tactile stimulation: Improving the treatment of Apnea of Prematurity
No full textApnea of prematurity is one of the most common diagnoses in the Neonatal Intensive Care Unit. Frequent breathing pauses occur in almost all infants born at <28 weeks gestational age or with a birth weight of <1000g and can result in serious brain damage. Medicines are used to suppress the apnea but are not able to eliminate it. Manual tactile stimulation is currently used to terminate apneas that occur despite the preventative treatment. However, the duration of apnea is dependent on the reaction of the nurse. A direct automatic response could significantly shorten the apnea hence reducing hypoxia and bradycardia and reduce the chance of infection due to cross-contamination. In addition, detecting imminent apnea could potentially prevent it. The goal of this graduation project was to find out the best way of preventing and terminating apnea in premature infants by automatic tactile stimulation. During this project three studies were performed. The first study was a literature review. The purpose of this review was to verify what is known about the effects of (automatic) tactile stimulation on the termination and prevention of apnea in preterm infants. This was done by systematically reviewing available literature. The results showed that the effects of touch, oscillation, pulsation and vibration were studied. In conclusion, although the big variations in study design, amount of subject etc., the majority of studies show positive results of tactile stimulation on the termination and prevention of apnea. However, it is not known which receptors are stimulated by specific stimuli and what their neuronal pathways are. Therefore it is currently hard to tell which stimulation mode and stimulation characteristics are most optimal for the termination and/or prevention of AOP. The second study focused on the design of a vibrotactile actuator that was suitable for comparing stimulation with different (stochastic) frequencies. Voice coils, linear resonant actuators and piëzo elements appeared to be most suitable for studies comparing the responses of vibrations with different frequencies. The selection of the right specific actuator is dependent on the frequencies and strokes that it should generate. In the final study the effect of stimulation stroke and stimulation spot on the regularity of breathing (experiment 1) and on the termination of apnea (experiment 2) in preterm rabbits were compared. The results the first experiment show that stochastic vibrations of 490-980Hz applied at the chest cause an increase in the variability of the breathing pattern compared with the same stimulation at the sole of the foot. However, statistical significance was only reaches for low stroke stimulation. The results of the second part of the experiment show that, in contrast with earlier performed studies, the vibratory stimulation does not reinitiate breathing following apnea provoked by hypoxia. This might be caused by the high frequency. However, it seems very likely that apnea caused by severe hypoxia requires more vigorous stimulation. All in all, automatic tactile stimulation seems to be able to improve the current treatment of AOP. However, more research is required to select the most optimal stimulus.Mechanical, Maritime and Materials EngineeringBiomedical Engineerin
Composition & Time: An Ode to Water
No full textWith this project, I explore the transformative affect of the architectural intervention, as a micro-regime of power itself; with a power that enables the mediation of control in the city and in this case, mediating the legibility of the flow resource, water, in the city of Agadir. I argue that with the articulation of proportion [eurythmy] , phenomena and order, the architectural intervention will overlay a set of values and instruction upon its subjects. Holding a dual relationship with the society it associates with; deriving of it whilst producing it. The articulation of these three paradigms; proportion, phenomena and order, together offer the extent of legibility and thus an attainable level of control or lack thereof; be it control over citizens, machinery, infrastructures, or politics. The objectives here are the empowerment of citizens, the deconstruction of a state agenda and the re-commoning of resources.Architecture and The Built EnvironmentArchitectur
Developing interest management techniques in distributed interactive simulation using Java
Get PDFBandwidth consumption in distributed real time simulation, or networked real time simulation, is a major problem as the number of participants and the sophistication of joint simulation exercises grow in size. The paper briefly reviews distributed real time simulation and bandwidth reduction techniques and introduces the Generic Runtime Infrastructure for Distributed Simulation (GRIDS) as a research architecture for studying such problems. GRIDS uses Java abstract classes to promote distributed services called thin agents, a novel approach to implementing distributed simulation services, such as user defined bandwidth reduction mechanisms, and to distributing the executable code across the simulation. Thin agents offer the advantages of traditional agents without the overhead imposed by mobility or continuous state, which are unnecessary in this context. We present our implementation and some predicted results from message reduction studies using thin agent
Initial orthostatic hypotension at high altitude
No full textThomas, Kate N., Keith R. Burgess, Rishi Basnyat, Samuel J.E. Lucas, James D. Cotter, Jui-Lin Fan, Karen C. Peebles, Rebekah A.I. Lucas, Philip N. Ainslie. Initial orthostatic hypotension at high altitude. High Alt. Med. Biol. 11:163-167, 2010.-There are several reports on syncope occurring following standing at high altitude (HA), yet description of the detailed physiological responses to standing at HA are lacking. We examined the hypothesis that appropriate physiological adjustments to upright posture would be compromised at HA (5050m). Ten healthy volunteers stood up rapidly from supine rest, for 3min, at sea level and at 5050m. Beat-to-beat mean arterial blood pressure (MAP, Finometer), middle cerebral artery blood velocity (MCAv, Transcranial Doppler), end-tidal PCO2and PO2, and heart rate (ECG) were recorded continuously. After 14 days at HA, baseline MAP and MCAv were not different to sea level, although HR was elevated. Neither the magnitude of initial (0.05). By 3min of standing, MAP was restored to supine values both at sea level (-3±12mmHg) and HA (4±10mmHg), although there was more complete recovery of HR at sea level (+13±10b/min, p=0.02 vs.+23±10b/min, p=0.01). Reduced MCAv at 3min was comparable at sea level and altitude (both-16%). These data indicate that initial cardiovascular and cerebrovascular responses to standing are unaltered when partially acclimatized to HA
Investigating distributed simulation with COTS simulation packages: Experiences with Simul8 and the HLA
No full textCommercial-off-the-shelf simulation packages (CSPs) are used widely in industry. Several research groups are currently working towards the creation of distributed simulation with these CSPs. The motivations to do this are various and are largely unproven as there are very few good examples of this kind of distributed simulation in practice. Our goal is therefore to create a distributed simulation environment using CSPs that will allow end users to make their own decisions as to whether this technology will be useful. This paper presents continuing research in creating such an environment using the CSP Simul8 and the High Level Architecture, the IEEE 1516 standard for distributed simulation. The scope of this paper is limited to the CSPI-PDG Type I Interoperability Reference Model
Genisa: A web-based interactive learning environment for teaching simulation modelling
No full textIntelligent Tutoring Systems (ITS) provide students with adaptive instruction and can facilitate the acquisition of problem solving skills in an interactive environment. This paper discusses the role of pedagogical strategies that have been implemented to facilitate the development of simulation modelling knowledge. The learning environment integrates case-based reasoning with interactive tools to guide tutorial remediation. The evaluation of the system shows that the model for pedagogical activities is a useful method for providing efficient simulation modelling instruction
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