Dynamic dictionary matching with failure functions

AbstractAmir and Farach (1991) and Amir et al. (to appear) recently initiated the study of the dynamic dictionary pattern matching problem. The dictionary D contains a set of patterns that can change over time by insertion and deletion of individual patterns. The user may also present a text string and ask to search for all occurrences of any patterns in the text. For the static dictionary problem, Aho and Corasick (1975) gave a strategy based on a failure function automaton that takes O(|D|log|Σ|) time to build a dictionary of size |D| and searches a text T in time O(|T|log|Σ|+tocc), where tocc, is the total number of pattern occurrences in the text.Amir et al. (to appear) used an automaton based on suffix trees to solve the dynamic problem. Their method can insert or delete a pattern P in time O(|P|log|D|) and can search a text in time O((|T|+tocc)log|D|).We show that the same bounds can be achieved using a framework based on failure functions. We then show that our approach also allows us to achieve faster search times at the expense of the update times; for constant k, we can achieve linear O(|T|(k+log|Σ|)+k tocc) search time with an update time of O(k|P∥D|1k). This is advantageous if the search texts are much larger than the dictionary or searches are more frequent than updates.Finally, we show how to build the initial dictionary in O(|D|log|Σ|) time, regardless of what combination of search and update times is used

On the Complexity of Local Search for Weighted Standard Set Problems

In this paper, we study the complexity of computing locally optimal solutions for weighted versions of standard set problems such as SetCover, SetPacking, and many more. For our investigation, we use the framework of PLS, as defined in Johnson et al., [JPY88]. We show that for most of these problems, computing a locally optimal solution is already PLS-complete for a simple neighborhood of size one. For the local search versions of weighted SetPacking and SetCover, we derive tight bounds for a simple neighborhood of size two. To the best of our knowledge, these are one of the very few PLS results about local search for weighted standard set problems

Bovine Fasciolose in bayerischen `Bio-Milchkuhbetrieben`: Prävalenz und Risikofaktoren

This study about fasciolosis in Bavarian dairy farms is part of the project “Tackling the parasitological challenges in organic ruminant farming systems (ProPara)” (Core Organic Plus).The first aim of this project was to analyse the prevalence of Fasciola hepatica in Bavarian organic dairy farms in comparison to conventional farms. For this purpose, 366 bulk tank milk (BTM) samples of Bavarian organic cattle herds and 366 BTM samples of Bavarian conventional farms were collected in October 2015. Seroprevalence of each BTM sample was estimated using the `IDEXX Fasciola hepatica Antibody Test Kit`. The second aim of this project was to identify risk factors for the transmission of F. hepatica, which are important especially for organic cattle farming. In order to exclude pasturing as a risk factor, only herds with grazing were included in the study. A questionnaire, including 37 questions, was discussed with each participating farmer by telephone. BTM or fecal samples of every herd was examined to assess the infectionstatus. Thus, the herds were divided into 4 groups: - organic Fasciola-negative, - organic Fasciola-positive, - conventional Fasciola-negative, - conventional Fasciola-positive. As risk factors in all herds breed, the collective grazing of different production groups (e. g. dairy and dry cows), grazing depending on the weather, and the percentage of pastures with wetlands

Chiral logic computing with twisted antiferromagnetic magnon modes

Antiferromagnetic (AFM) materials offer an exciting platform for ultrafast information handling with low cross-talks and compatibility with existing technology. Particularly interesting for low-energy cost computing is the spin wave-based realization of logic gates, which has been demonstrated experimentally for ferromagnetic waveguides. Here, we predict chiral magnonic eigenmodes with a finite intrinsic, magnonic orbital angular momentum ℓ in AFM waveguides. ℓ is an unbounded integer determined by the spatial topology of the mode. We show how these chiral modes can serve for multiplex AFM magnonic computing by demonstrating the operation of several symmetry- and topology-protected logic gates. A Dzyaloshinskii–Moriya interaction may arise at the waveguide boundaries, allowing coupling to external electric fields and resulting in a Faraday effect. The uncovered aspects highlight the potential of AFM spintronics for swift data communication and handling with high fidelity and at a low-energy cost

Soft Wrist Exosuit Actuated by Fabric Pneumatic Artificial Muscles

Recently, soft actuator-based exosuits have gained interest, due to their high strength-to-weight ratio, inherent safety, and low cost. We present a novel wrist exosuit actuated by fabric pneumatic artificial muscles that can move the wrist in flexion/extension and ulnar/radial deviation. We derive a model representing the torque exerted by the exosuit and introduce a model-based optimization methodology for the selection of placement parameters of the exosuit muscles. We evaluate the accuracy of the model by measuring the exosuit torques throughout the full range of wrist flexion/extension. When accounting for the displacement of the mounting points, the model predicts the exosuit torque with a mean absolute error of 0.279 Nm, which is 26.1% of the average measured torque. To explore the capabilities of the exosuit to move the human body, we measure its range of motion on a passive human wrist; the exosuit is able to achieve 55.0% of the active biological range in flexion, 69.1% in extension, 68.6% in ulnar deviation, and 68.4% in radial deviation. Finally, we demonstrate the device controlling the passive human wrist to move to a desired orientation in the flexion/extension plane and along a two-degree-of-freedom trajectory.Comment: 16 pages, 15 figure

Tunable all-fibre delay line filter for residual dispersion compensation in 40 Gbit/s systems

A novel all-fibre tunable delay-line filter, with a simple structure based on two 3×3 fibre couplers and only one phase shifter is utilised for residual dispersion compensation in a 40 Gbit/s optical transmission system. In this experiment the dispersion tolerance of the receiver was successfully enhanced by 100 ps/nm