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Visar resultat 1 - 5 av 208 avhandlingar som matchar ovanstående sökkriterier.
1. Distributed thermal response tests : New insights on U-pipe and Coaxial heat exchangers in groundwater-filled boreholes
Sammanfattning : U-pipe Borehole Heat Exchangers (BHE) are widely used today in ground source heating and cooling systems in spite of their less than optimal performance. This thesis provides a better understanding on the function of U-pipe BHEs and Investigates alternative methods to reduce the temperature difference between the circulating fluid and the borehole wall, including one thermosyphon and three different types of coaxial BHEs. LÄS MER
2. Secure GNSS-based Positioning and Timing : Distance-Decreasing attacks, fault detection and exclusion, and attack detection with the help of opportunistic signals
Sammanfattning : With trillions of devices connected in large scale systems in a wired or wireless manner, positioning and synchronization become vital. Global Navigation Satellite System (GNSS) is the first choice to provide global coverage for positioning and synchronization services. LÄS MER
3. Multiscale granular mechanics: A neutron diffraction based experimental approach
Sammanfattning : Granular media (i.e., assemblies of grains, containing voids), such as sand, are highly complex materials, possessing inherently heterogeneous structure and properties that are manifested by the mobility and interaction of their constituent particles. Despite having been widely studied for centuries (i. LÄS MER
4. Structural Reliability and Identification with Stochastic Simulation - Application to Railway Mechanics
Sammanfattning : System identification of structures based on measured response data can play a key role in improving reliability based structural designs. However, the experimental limitations of in situ tests and uncertainties of required model complexity together with the inverse nature of system identification give rise to a number of challenging issues. LÄS MER
5. GNSS hardware biases in code and carrier phase observables
Sammanfattning : GNSS hardware biases appear in code and phase observations, and originates both from the receiver and satellite hardware. The presence of biases in GNSS observations might affect the accuracy in precise GNSS positioning applications, and might also be of relevance in other GNSS applications. LÄS MER