1,721,061 research outputs found
The Complexity of Finding Supergraphs
No full textWe consider several variations of the following problem: fix a countable graph G. Is an input graph H a(n induced) subgraph of G? If yes, can we find a copy of H in G? The challenge to classify the Weihrauch degrees of such problems was put forth recently by BeMent, Hirst, and Wallace (“Reverse mathematics and Weihrauch analysis motivated by finite complexity theory”, Computability, 2021). We report some initial results here, and in particular, solve one of their open questions
THE WEIHRAUCH LATTICE AT THE LEVEL OF Π11-CA0: THE CANTOR-BENDIXSON THEOREM
Full text linkThis paper continues the program connecting reverse mathematics and computable analysis via the framework ofWeihrauch reducibility. In particular, we consider problems related to perfect subsets of Polish spaces, studying the perfect set theorem, the Cantor-Bendixson theorem, and various problems arising from them. In the framework of reverse mathematics, these theorems are equivalent, respectively, to ATR0 and Π11 -CA0, the two strongest subsystems of second order arithmetic among the so-called big five. As far as we know, this is the first systematic study of problems at the level of Π11 -CA0 in the Weihrauch lattice.We show that the strength of some of the problems we study depends on the topological properties of the Polish space under consideration, while others have the same strength once the space is rich enough
Learning algebraic structures with the help of Borel equivalence relations
Full text linkWe study algorithmic learning of algebraic structures. In our framework, a learner receives larger and larger pieces of an arbitrary copy of a computable structure and, at each stage, is required to output a conjecture about the isomorphism type of such a structure. The learning is successful if the conjectures eventually stabilize to a correct guess. We prove that a family of structures is learnable if and only if its learning domain is continuously reducible to the relation E0 of eventual agreement on reals. This motivates a novel research program, that is, using descriptive set theoretic tools to calibrate the (learning) complexity of nonlearnable families. Here, we focus on the learning power of well-known benchmark Borel equivalence relations (i.e., E1, E2, E3, Z0, and Eset)
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
A novel chimeric cellulase by combining CelA of Dictyoglomus turgidum with the carbohydrate binding module CBM11 from Clostridium thermocellum
No full textNeural Network for next day prediction energy consumption: the leaf lab case study
Full text linkEnergy management have always been a great challenge in our society. The prediction of energy consumption of offices, apartments and even entire buildings could be the key for helping in reducing the energy utilization, in designing and sizing renewable energy and storage systems [1]. In this work we compared a combination of different architectures parameters and paradigms in order to forecast the next day energy consumption.
Our data are the recordings of the energy consumption and external temperatures in a period of two years, of the Leaf Lab, a building belonging to the Loccioni Group s.p.a. that kindly provided us those data. Feedforward, with different topologies, and Recurrent neural networks with a long short term memory unit have been used [2,3].
We trained and tested our networks using the data of the first year and then we forecasted the daily consumption of the next one. We evaluated each network in terms of the Mean Absolute Percentage Error (MAPE), the Mean Squared Error, (MSE) and the Root Mean Squared Error (RMSE). We got that the recurrent neural network performed better that the others obtaining a MAPE of 22%, a MSE of 18.03 and a RMSE of 4.25.
In this work, contrary to what is reported in the literature, validation has been carried out over a long period (one year); moreover, the data provided were noisy and had a large number of "holes". Despite this, our network managed to contain the error in almost all the predictions; only some of these presented a very high error.
References:
1) Chengdong, L.; Zixiang, D., Dongbin, Z., Jianqiang, Y., Guiqing, Z. Energies , 2017, 10.
2) Rodrigues, F.; Cardeira, C., Calado, J.M.F. 6th International Conference on Sustainability in Energy and buildings, 2014, 62 220-29.
3) Hochreiter, S.; Schmidhuber, J. Neural Comput., 1997, 9(8), 1735-1780
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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