621 research outputs found
Design tool for a 6-DOF planar motor with moving permanent magnets and standstill coils
This paper describes a fast design tool, which can be used for the rapid modelling, evaluation and optimisation of a moving magnet planar motor. It can be used as an alternative to slow three-dimensional finite element simulations and can calculate forces and torques on the moving platform, which can be positioned in 6-DoF with respect to the stationary part. The force calculations are validated using finite element simulations
An Embedded Domain-Specific Language for Logical Circuit Descriptions with Applications to Garbled Circuits
Contemporary libraries and frameworks that make it possible to incorporate secure multi-party computation protocols and capabilities into production software systems and applications must sometimes deliver underlying capabilities (such as logical circuit synthesis) to new kinds of environments (such as web browsers or serverless cloud computing platforms). In order to illustrate some of the benefits of addressing this challenge by building a solution from the ground up that leverages the features of a contemporary and widely used programming language, we present an embedded domain-specific language that allows programmers to describe and synthesize logical circuits. Notably, this approach allows programmers to employ many of the language features and any of the programming paradigms supported by the host language. We illustrate this flexibility by considering two use cases: synthesizing circuits for relational operations and synthesizing circuits corresponding to the SHA-256 cryptographic hash function
Asynchronous Delegated Private Set Intersection with Hiding of Intersection Size
Integrating private set intersection (PSI) protocols within real-world data workflows, software applications, or web services can be challenging. This can occur because data contributors and result recipients do not have the technical expertise, information technology infrastructure, or other resources to participate throughout the execution of a protocol and/or to incur all the communication costs associated with participation. Furthermore, contemporary workflows, applications, and services are often designed around RESTful APIs that might not require contributors or recipients to remain online or to maintain state. Asynchronous delegated PSI protocol variants can better match the expectations of software engineers by (1) allowing data contributors to contribute their inputs and then to depart permanently, and (2) allowing result recipients to request their result only once they are ready to do so. However, such protocols usually accomplish this by introducing an additional party that learns some information about the size of the intersection. This work presents an asynchronous delegated PSI protocol variant that does not reveal the intersection size to the additional party. It is shown that such a protocol can have, on average, linear time and space complexity
An Exciton Dynamics Model of Bryopsis corticulans Light-Harvesting Complex II
Bryopsis corticulans is a marine green macroalga adapted to the intertidal environment. It possesses siphonaxanthin-binding light-harvesting complexes of photosystem II (LHCII) with spectroscopic properties markedly different from the LHCII in plants. By applying a phenomenological fitting procedure to the two-dimensional electronic spectra of the LHCII from B. corticulans measured at 77 K, we can extract information about the excitonic states and energy-transfer processes. The fitting method results in well-converged parameters, including excitonic energy levels with their respective transition dipole moments, spectral widths, energy-transfer rates, and coupling properties. The 2D spectra simulated from the fitted parameters concur very well with the experimental data, showing the robustness of the fitting method. An excitonic energy-transfer scheme can be constructed from the fitting parameters. It shows the rapid energy transfer from chlorophylls (Chls) b to a at subpicosecond time scales and a long-lived state in the Chl b region at around 659 nm. Three weakly connected terminal states are resolved at 671, 675, and 677 nm. The lowest state is higher in energy than that in plant LHCII, which is probably because of the fewer number of Chls a in a B. corticulans LHCII monomer. Modeling based on existing Hamiltonians for the plant LHCII structure with two Chls a switched to Chls b suggests several possible Chl a-b replacements in comparison with those of plant LHCII. The adaptive changes result in a slower energy equilibration in the complex, revealed by the longer relaxation times of several exciton states compared to those of plant LHCII. The strength of our phenomenological fitting method for obtaining excitonic energy levels and energy-transfer network is put to the test in systems such as B. corticulans LHCII, where prior knowledge on exact assignment and spatial locations of pigments are lacking
The effect of feeding time on dispersal of Virola seeds by toucans determined from GPS tracking and accelerometers
Directed seed dispersal towards areas with low conspecific tree density by a scatter-hoarding rodent
Negative density dependence of seed dispersal and seedling recruitment in a Neotropical palm
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Improved Upper Limit on the Neutrino Mass from a Direct Kinematic Method by KATRIN.
We report on the neutrino mass measurement result from the first four-week science run of the Karlsruhe Tritium Neutrino experiment KATRIN in spring 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are energy analyzed by a high-resolution MAC-E filter. A fit of the integrated electron spectrum over a narrow interval around the kinematic end point at 18.57 keV gives an effective neutrino mass square value of (-1.0_{-1.1}^{+0.9})  eV^{2}. From this, we derive an upper limit of 1.1 eV (90% confidence level) on the absolute mass scale of neutrinos. This value coincides with the KATRIN sensitivity. It improves upon previous mass limits from kinematic measurements by almost a factor of 2 and provides model-independent input to cosmological studies of structure formation
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