70 research outputs found
Supplemental Material, Appendix_revised - Determinants of Cross-Sectional and Longitudinal Health-Related Quality of Life in Memory Clinic Patients Without Dementia
No full textSupplemental Material, Appendix_revised for Determinants of Cross-Sectional and Longitudinal Health-Related Quality of Life in Memory Clinic Patients Without Dementia by Leonie C. P. Banning, Eveline P. C. J. Janssen, Renske E. G. Hamel, Marjolein de Vugt, Sebastian Köhler, Claire A. G. Wolfs, Saskia M. Oosterveld, Rene J. F. Melis, Marcel G. M. Olde Rikkert, Roy P. C. Kessels, Yolande A. L. Pijnenburg, Ted Koene, Wiesje M. van der Flier, Philip Scheltens, Pieter Jelle Visser, Frans R. J. Verhey, Pauline Aalten and Inez H. G. B. Ramakers in Journal of Geriatric Psychiatry and Neurology</p
Datatransmissie-metingen aan een verbinding via de huistelefooncentrale EBX 8000 bij transmissiesnelheden van 19.2 tot en met 192 k bit/s
No full textMetingen werden verricht aan een verbinding vanuit het gebouw voor Electrotechniek naar de EBX 8000 en terug. Deze metingen zijn een vervolg op de metingen gedaan door A. Koene. Het verschil is dat er nu gebruik is gemaakt van bredebandmodems en hogere transmissiesnelheden. Ook bij 192.000 bit/s, de hoogste gebruikte snelheid, blijkt er nog een goede verbinding mogelijk te zijn.Applied SciencesTransmissie van Informati
Data-driven 3D Deghosting Using Multisensor Marine Measurements
No full textMarine seismic acquisition tows submerged streamers to record pressure waves from the subsurface. The recording, however, contains both the desired upgoing wavefield and its (immediate) reflection off the sea-surface, causing a downgoing wavefield known as the seismic ghost. Interference between the up- and downgoing waves causes periodic low signal to noise ratio (S/N) ‘ghost notches’ in the recorded spectrum. To restore the broadband upgoing signal, we must remove the ghost (‘deghosting’). Deghosting using solely pressure measurements fails to restore the signal in the low S/N notches of the data. Current acquisition techniques acquire signals with different ghost notches, such that their proper combination recovers the broadband signal. This thesis uses multisensor acquisition: measurements of the pressure and particle velocity vector. The ghost notches on the pressure and vertical particle velocity are offset by half a period, such that their combination may provide good S/N at all frequencies. Current multisensor deghosting techniques make deterministic assumptions on the data and ghost model (such as a known streamer depth, or assuming energy propagating only along the streamer). If the assumptions do not correspond to the data, the deghosting fails to restore the true broadband signal. We propose two novel data-driven deghosting techniques, which estimate an adequate deghosting filter based on the data itself. The first method estimates the 3D propagation of energy using measurements of the pressure and crossline particle velocity along a single streamer. The 3D incidence angle is used to sum the pressure wave with vertical particle velocity such that only the upgoing wave is recovered. The second method estimates the filter parameters that explain the recorded ghosted data by minimizing a multisensor least-squares deghosting cost function. The cost function is analytically shown to outperform similar single sensor adaptive deghosting techniques in terms of sensitivity to the true ghost model. The obtained filter parameters may then be used to construct an inverse filter that restores the upgoing wavefield. We found that both methods produce encouraging results on real data, outperforming the existing deterministic multisensor deghosting methods.Civil Engineering and GeosciencesGeoscience & EngineeringApplied Geophysic
Invloed van gesuspendeerd deeltjes op de stofoverdrachtscoefficient K1
No full textKramers Laboratorium voor Fysische TechnologieApplied Science
Algorithmic bias: addressing growing concerns
No full textIn the context of the IEEE Global Initiative for Ethical Considerations in Artificial Intelligence and Autonomous Systems, and with support from its executive director, the author have proposed the development of a new IEEE Standard on Algorithmic Bias Considerations. The aim is for this to become part of a set of ethical design standards, such as the IEEE P7001™ Standards Project called Transparency of Autonomous Systems with a Working Group. Whereas the Transparency of Autonomous Systems Standard will be focused on the important issue of “breaking open the black box” for users and/or regulators, the Algorithmic Bias Standard is focused on “surfacing” and evaluating societal implications of the outcomes of algorithmic systems, with the aim of countering non-operationally-justified results
Urban Stress: Research into the reduction of urban stress through urban design
No full textStress is a well-known phenomenon and something everyone experiences. Urban stress however, stress caused by and in the built environment of urban areas, is less known. Still, quite some research has been done on this topic from the fields of sociology and psychology, but there are not many resources that focus on urban stress - with all its stressors - in general, and the relation between urban stress and urban design is also still thin. Therefore, this thesis focusses on getting a better overview of urban stressors, their relation to the public space and how urban stress can be reduced through urban design. This is mainly done by literature research and design, and the interaction between them, but is also supported by interviews, site analysis, data review and testing. Stress can be reduced using a direct approach or an indirect approach. The direct approach focusses directly on the stressor, while the indirect approach tries to decrease the negative effect of the stressor, or of the stress itself. The indirect approach can be divided into three sub-approaches: perceived control, pro-social places and restorative environments. Perceived control is important because people experience less stress if they feel like they are in control of their environment. Pro-social places, or social support, is one of the ways to cope with stress. Restoration is recovering from stress and might therefore be the most important indirect approach. It turns out that the scale of the public space within the scale of the project area of this thesis is very suited for the indirect approaches. An urban design is made for four different locations in Caledonian, London, using these indirect approaches.Architecture, Urbanism and Building Sciences | Design of the Urban Fabri
Design and Validation of Ungrounded Wrist Perturbator Based On Parallel Mechanism
No full textThe compliance (stiffness) of a human arm varies, depending on the task at hand. Some precise tasks require high stiffness, while others need a level of flexibility to deal with unknown disturbances. To describe this human behaviour a portable device is needed to give small force perturbations (input) while the resulting reaction of the arm (output) is measured. There are multiple state-of-the-art devices to choose from to provide such input. However, the majority of these devices either offer too little versatility or impede the free movement of the user. Implementation of a novel parallel mechanism allows for a lightweight (0.175kg) and compact device that can generate various signals in three degrees-of-freedom. Since the device is designed to be mounted around the wrist, it leaves your arm and hand unobstructed. A full-scale prototype is constructed and the concept is tested using a force sensor. Implementing powerful yet compact servo motors allows for controlled perturbations in the order of 4N, with bandwidths up to 12Hz.Mechanical Engineering | Mechatronic System Design (MSD
Evaluation of Micromixing Models for Turbulent Mixing in Supercritical Water
No full textHydrothermal flames have become a very important field of study, especially for supercritical water oxidation. In supercritical water oxidation hazardous, toxic or non-biodegradable aqueous organic waste water streams can be efficiently destructed. Supercritical water oxidation takes place in a aqueous environment above the supercritical point.In the case of turbulent flow, micromixing models are needed.In this work, three different mixing models are analysed in a hydrothermal flame environment. These models are Interaction by Exchange with the Mean, Coalescence/Dispersion and the Mapping Closure model. When the mixing is done around temperatures far below or far above the pseudocritical temperature all models gave the same evolution of average temperature. However when the mixing is done around the pseudocritical temperature the differences are large. The Mapping Closure model is best in agreement with the Navier-Stokes equations so it is advised to use that model when simulating mixing around the pseudocritical temperature
Implementation and Evaluation of Packed-SIMD Instructions for a RISC-V Processor
No full textWith the increase in the amount of data being gathered, the need for data processing is also rising. Furthermore, in addition to the proprietary ISAs that have been prevalent, the free and open RISC-V ISA has seen major interest. The modularity of the RISC-V ISA allows it to be extended with many instruction set extensions. One such extension that aids in the processing of large amounts of data is the P-extension, which introduces packed-SIMD instructions. In this thesis, the RISC-V based open-source CVA6 processor is extended to support the SIMD instructions defined by the P-extension. In order to do so, the 332 instructions of the P-extension are divided into subsets based on the type of instructions used by applications that make use of SIMD instructions and the hardware needed to implement those instructions. Due to time constraints 268, or 80.7%, of the total 332 instructions were implemented. However, this includes all the instructions that could be utilized by the used benchmarks. Therefore, the benchmark results show the full performance achievable by the P-extension. These 268 instructions make up the basic, MAC 8-bit, MAC 16-bit, and MAC 32-bit subsets. The ALU has been modified to operate in a SIMD manner on 8 8-bit, 4 16-bit, 2 32-bit, and 64-bit elements. Moreover, it has been extended to support new operations like data movement or reorganization instructions. Like the ALU, the multiplier has also been converted into a SIMD multiplier using a SIMD Baugh-Wooley scheme. Furthermore, the multiplier has been extended to also function as a MAC unit. The impact of these newly added SIMD instructions is tested in an ideal scenario of matrix multiplication as well as in a real-world machine learning application. In matrix multiplication, a speedup of up to 8.8x and 7.2x is seen for 8-bit and Q7 elements and 4.9x and 3.8x for 16-bit and Q15 elements when only using instructions from the basic subset. When also using the MAC instructions, the speedup increases to up to 12.3x and 12.6x for 8-bit and Q7 elements and 6.7x and 6.5x for 16-bit and Q15 elements. The real-world benchmark consists of an image recognition convolutional neural network based on the CIFAR-10 data set. In this benchmark, a speedup of 2.1x and 3.3x is obtained for respectively the basic subset and with MAC instructions. However, the additional hardware comes at a cost, specifically an increase of 5.0% LUT and 0.05% flip-flop usage for the basic subset or 7.2% increased LUT and 0.56% increased flip-flop usage with the basic and MAC subsets. While the additional hardware can have an impact on the maximum achievable clock frequency, the critical path remains in the FPU. The maximum achievable clock frequency is therefore not impacted and reaches 70 MHz on a Xilinx Kintex-7 FPGA
SoftGlove: Finger Vibrotactile Feedback
No full textIn this report the finger vibrotactile subsystem of the SoftGlove wearable haptic feedback glove is discussed. This system is an upgrade over the vibrotactile feedback that the current SenseGlove haptic feedback glove provides. The designed system consists of a linear resonant actuator (LRA) on each finger, which is controlled by a dedicated LRA driver over I2C. To overcome addressing limitations of the drivers, an I2C switch is used to be able to communicate with each driver individually. The system is characterized both in terms of latency and vibration strength. The peak-to-peak vibration strength is measured to be 1.44 G and a 10 % to 90 % rise and fall time of 44 ms from rest to the maximum vibration strength. Furthermore, the system is integrated with the other subsystems of the SoftGlove on a PCB.SoftgloveElectrical Engineerin
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