1,721,603 research outputs found
On the Complexity of Solving Restricted Word Equations
No full textWe investigate the complexity of the solvability problem for restricted classes of word equations with and without regular constraints. The solvability problem for unrestricted word equations remains [Formula: see text]-hard, even if, on both sides, between any two occurrences of the same variable no other different variable occurs\; for word equations with regular constraints, the solvability problems remains [Formula: see text]-hard for equations whose two sides share no variables or with two variables, only one of which is repeated. On the other hand, word equations with only one repeated variable (but an arbitrary number of variables) and at least one non-repeated variable on each side, can be solved in polynomial-time
Revisiting Weighted Information Extraction: A Simpler and Faster Algorithm for Ranked Enumeration
No full textInformation extraction from textual data, where the query is represented by a finite transducer and the task is to enumerate all results without repetition, and its extension to the weighted case, where each output element has a weight and the output elements are to be enumerated sorted by their weights, are important and well studied problems in database theory. On the one hand, the first framework already covers the well-known case of regular document spanners, while the latter setting covers several practically relevant tasks that cannot be described in the unweighted setting. It is known that in the unweighted case this problem can be solved with linear time preprocessing O(|D|) and output-linear delay O(|s|) in data complexity, where D is the input data and s is the current output element. For the weighted case, Bourhis, Grez, Jachiet, and Riveros [ICDT 2021] recently designed an algorithm with linear time preprocessing, but the delay of O(|s| · log|D|) depends on the size of the data. We first show how to leverage the existing results on enumerating shortest paths to obtain a simple alternative algorithm with linear preprocessing and a delay of O(|s i | + min\ log i, log|D| ) for the i th output element s i (in data complexity); thus, substantially improving the previous algorithm. Next, we develop a technically involved rounding technique that allows us to devise an algorithm with linear time preprocessing and output-linear delay O(|s|) with high probability. To this end, we combine tools from algebra, high-dimensional geometry, and linear programming
Efficient Algorithms and Complexity Results
No full textA pattern ɑ (i.e., a string of variables and terminals) matches a word w , if w can be obtained by uniformly replacing the variables of ɑ by terminal words. The respective matching problem, i.e., deciding whether or not a given pattern matches a given word, is generally NP-complete, but can be solved in polynomial-time for restricted classes of patterns. We present efficient algorithms for the matching problem with respect to patterns with a bounded number of repeated variables and patterns with a structural restriction on the order of variables. Furthermore, we show that it is NP-complete to decide, for a given number k and a word w , whether w can be factorised into k distinct factors. As an immediate consequence of this hardness result, the injective version (i.e., different variables are replaced by different words) of the matching problem is NP-complete even for very restricted classes of patterns
The splicing genes SmEa and SmEb regulate plant development during vegetative growth in poplar
No full textBackground: Spliceosomes are large evolutionary conserved ribonucleoprotein complexes containing at their core heptameric rings of Sm (or LSm) proteins and U-rich snRNAs. The role of Sm proteins in animal development is well established, and recent research has begun to link mutations in these genes to growth defects in plants. One of the most studied Sm genes is SmE1/PCP, mutants of which display a temperature-dependent phenotype in Arabidopsis thaliana. Results: This study provides a first glimpse into the function of a core splicing protein in the regulation of growth in a perennial species. Phylogenetic analysis identified two paralogous SmE genes in poplar, named SmEa and SmEb, that encode identical proteins and are orthologs of SmEs from Arabidopsis, as suggested by Y2H and in vivo experiments. CRISPR/Cas9 mutagenesis in hybrid aspen identified a role for SmEs in development in plants grown in an environment simulating seasonal photoperiod and temperature changes. Unlike in Arabidopsis, low temperatures had no or only a very minor effect on the development of sme mutants in aspen. Conclusions: We identified specific aspects of SmE in poplar, highlighting the importance of examining the physiological and evolutionary differences that define this gene family in woody compared to herbaceous plants
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Optimization Strategies to Adapt Sheep Breeding Programs to Pasture-Based Production Environments: A Simulation Study
No full textStrong differences between the selection (indoor fattening) and production environment (pasture fattening) are expected to reduce genetic gain due to possible genotype-by-environment interactions (G × E). To investigate how to adapt a sheep breeding program to a pasture-based production environment, different scenarios were simulated for the German Merino sheep population using the R package Modular Breeding Program Simulator (MoBPS). All relevant selection steps and a multivariate pedigree-based BLUP breeding value estimation were included. The reference scenario included progeny testing at stations to evaluate the fattening performance and carcass traits. It was compared to alternative scenarios varying in the progeny testing scheme for fattening traits (station and/or field). The total merit index (TMI) set pasture-based lamb fattening as a breeding goal, i.e., field fattening traits were weighted. Regarding the TMI, the scenario with progeny testing both in the field and on station led to a significant increase in genetic gain compared with the reference scenario. Regarding fattening traits, genetic gain was significantly increased in the alternative scenarios in which field progeny testing was performed. In the presence of G × E, the study showed that the selection environment should match the production environment (pasture) to avoid losses in genetic gain. As most breeding goals also contain traits not recordable in field testing, the combination of both field and station testing is required to maximize genetic gain
Auf dem Weg zu Wohlfahrt 4.0? : die Digitalisierung des Wohlfahrtsstaates in den Politikfeldern Arbeit, Gesundheit und Innovation im europäischen Vergleich
No full textDaniel Buhr, Claudia Christ, Rolf Frankenberger, Marie-Christine Fregin, Josef Schmid, Markus Träme
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