InstanceRank: Bringing order to datasets

In this paper we present InstanceRank, a ranking algorithm that reflects the relevance of the instances within a dataset. InstanceRank applies a similar solution to that used by PageRank, the web pages ranking algorithm in the Google search engine. We also present ISR, an instance selection technique that uses InstanceRank. This algorithm chooses the most representative instances from a learning database. Experiments show that ISR algorithm, with InstanceRank as ranking criteria, obtains similar results in accuracy to other instance reduction techniques, noticeably reducing the size of the instance set.Ministerio de Educación y Ciencia HUM2007-66607-C04-0

Diastereoisomerism, Stability, and Morphology of Substituted meso-4-Sulfonatophenylporphyrin J-Aggregates

The comparison between nanoparticle morphologies of the J-aggregates of different meso-4-sulfonatophenylporphyrins showing non-sulfonato groups at some of the meso-positions constitutes an ultimate proof of the 2D crystal-like character of the basic self-assembly motif of this family of J-aggregates. Diastereoisomerism stemming from the tacticity of the relative configurations in relation to the J-aggregate bidimensional sheet is the key factor that determines both the striking monolayer in solution and also the hierarchical pathways leading to different nanoparticle morphologies upon further growth. The unexpected stability of such large monolayered sheets made up of porphyrin units is probably caused by the support originated at both surface faces by the double layer potentials of the peripheral ionic substituents. These double layer potentials play a driving role in the subsequent 3D growth of the monolayers, as deduced herein from the determining role of tacticity both in the stability of the J-aggregate sheet and in its evolution either to monolayered or to bilayered nanoparticles. The stabilizing role of the forces at the electrical double layer of the particle suggests a relationship between these forces and the previously reported detection of racemic biases when shear hydrodynamic forces are in action during the aggregation process

PolaritySpam: Propagating Content-based Information Through a Web-Graph to Detect Web Spam

Spam web pages have become a problem for Information Retrieval systems due to the negative effects that this phenomenon can cause in their results. In this work we tackle the problem of detecting these pages with a propagation algorithm that, taking as input a web graph, chooses a set of spam and not-spam web pages in order to spread their spam likelihood over the rest of the network. Thus we take advantage of the links between pages to obtain a ranking of pages according to their relevance and their spam likelihood. Our intuition consists in giving a high reputation to those pages related to relevant ones, and giving a high spam likelihood to the pages linked to spam web pages. We introduce the novelty of including the content of the web pages in the computation of an a priori estimation of the spam likelihood of the pages, and propagate this information. Our graph-based algorithm computes two scores for each node in the graph. Intuitively, these values represent how bad or good (spam-like or not) is a web page, according to its textual content and its relations in the graph. The experimental results show that our method outperforms other techniques for spam detectionMinisterio de Educación y Ciencia HUM2007-66607-C04-0

Skid Resistance Analysis of Urban Bike Lane Pavements for Safe Micromobility

[EN] The use of micromobility vehicles is considerably growing in cities worldwide. As a result, crashes involving these vehicles are also increasing, with single-bicycle crashes accounting for a significant percentage. In most infrastructure-related crashes, the road surface was slippery. In this context, the study of pavement skid resistance is crucial to improve micromobility safety. In this research, the British pendulum tester was used to test the skid resistance of 5 different types of pavements on 17 bike lane locations in Valencia (Spain). Additionally, micromobility users¿ speed was collected to analyse users¿ behaviour. The results showed that asphalt, concrete, and rough painted tile pavements had the greatest skid resistance, whereas painted cobble and smooth painted tile pavements presented poor skid resistance. These values were compared with the limits set by the few guidelines that includes skid resistance thresholds. Moreover, skid resistance variability was also studied, with asphalt pavement being the most homogeneous. Based on the results of the research, several recommendations are proposed for the pavement to be used in the micromobility facility according to its typology. To this end, the investigatory level of skid resistance and the minimum braking distance required were also defined for each type of pavement and bike lane. The findings of this study contribute to the consideration of micromobility safety from the construction stage to the pavement management.This research is part of the research project PID2019-111744RB-I00, funded by MCIN/AEI/10.13039/501100011033.López-Molina, M.; Llopis-Castelló, D.; Pérez Zuriaga, AM.; Alonso-Troyano, C.; García García, A. (2023). Skid Resistance Analysis of Urban Bike Lane Pavements for Safe Micromobility. Sustainability. 15(1):1-16. https://doi.org/10.3390/su1501069811615

PolarityRank: Finding an equilibrium between followers and contraries in a network

In this paper we present the relevance ranking algorithm named PolarityRank. This algorithm is inspired in PageRank, the webpage relevance calculus method used by Google, and generalizes it to deal with graphs having not only positive but also negative weighted arcs. Besides the definition of our algorithm, this paper includes the algebraic justification, the convergence demonstration and an empirical study in which PolarityRank is applied to two unrelated tasks where a graph with positive and negative weights can be built: the calculation of word semantic orientation and instance selection from a learning dataset

Micromobility Users' Behaviour and Perceived Risk During Meeting Manoeuvres

[EN] Mobility patterns and lifestyles have changed in recent years in cities worldwide, thanks to the strong rise in modes of travel commonly referred to as micromobility. In this context, e-scooters have experienced a great rise globally which has led to an increase of crashes involving this type of micromobility vehicle in urban areas. Thus, there is a need to study e-scooter users¿ behaviour and their interaction with cyclists. This research aimed at characterizing the meeting manoeuvre between micromobility users along diverse typologies of two-way bicycle track by using an in-strumented e-scooter. As a result, bicycle tracks having concrete or vegetated curb presented lower clearance distance (¿0.8 m) than those without edge elements (>1 m), with no statistically signif-icant differences found between the interaction with bicycles and e-scooters. Additionally, an online questionnaire was proposed to assess users¿ perceived risk during the meeting manoeuvre, concluding that micromobility users feel safer and more comfortable riding on pavements away from parked or moving motorized traffic, and on protected bicycle tracks.FundingThis research is part of the research project PID2019-111744RB-I00, funded by MCIN/AEI/10.13039/501100011033.Fonseca-Cabrera, AS.; Llopis-Castelló, D.; Pérez Zuriaga, AM.; Alonso-Troyano, C.; García García, A. (2021). Micromobility Users' Behaviour and Perceived Risk During Meeting Manoeuvres. International Journal of Environmental research and Public Health (Online). 18(23):1-15. https://doi.org/10.3390/ijerph182312465S115182

A crystalline and free-standing silver thiocarboxylate thin-film showing high green to yellow luminescence

The simple direct synthesis of Cu(ii) and Ag(i) salts and thiobenzoic acid under ambient conditions allows the preparation of two bidimensional coordination polymers [M(TB)]n (TB = thiobenzoate; M = Cu (1) or Ag (2)). Their electrical and luminescent properties show that these are multifunctional materials. Interestingly 1 and 2 undergo a reversible solubilization process. This unusual feature and their simple preparation allow us to prepare a crystalline and free-standing thin-film of 2, using an interfacial procedure, which shows a remarkable thermochromic luminescence.This work was supported by MICINN (MAT2013-46753-C2-1-P and CTQ2013-48635-C2-1-P) and Generalitat Valenciana (projects PrometeoII/2014/076 and ISIC

MCFS: Min-cut-based feature-selection

In this paper, MCFS (Min-Cut-based feature-selection) is presented, which is a feature-selection algorithm based on the representation of the features in a dataset by means of a directed graph. The main contribution of our work is to show the usefulness of a general graph-processing technique in the feature-selection problem for classification datasets. The vertices of the graphs used herein are the features together with two special-purpose vertices (one of which denotes high correlation to the feature class of the dataset, and the other denotes a low correlation to the feature class). The edges are functions of the correlations among the features and also between the features and the classes. A classic max-flow min-cut algorithm is applied to this graph. The cut returned by this algorithm provides the selected features. We have compared the results of our proposal with well-known feature-selection techniques. Our algorithm obtains results statistically similar to those achieved by the other techniques in terms of number of features selected, while additionally significantly improving the accuracy.Ministerio de Ciencia, Innovación y Universidades RTI2018-098 062-A-I00Ministerio de Economía y Competitividad TIN2017-82113-C2-1-

‘Long autonomy or long delay?’ The importance of domain in opinion mining

Nowadays, people do not only navigate the web, but they also contribute contents to the Internet. Among other things, they write their thoughts and opinions in review sites, forums, social networks, blogs and other websites. These opinions constitute a valuable resource for businesses, governments and consumers. In the last years, some researchers have proposed opinion extraction systems, mostly domain-independent ones, to automatically extract structured representations of opinions contained in those texts. In this work, we tackle this task in a domain-oriented approach, defining a set of domain-specific resources which capture valuable knowledge about how people express opinions on a given domain. These resources are automatically induced from a set of annotated documents. Some experiments were carried out on three different domains (user-generated reviews of headphones, hotels and cars), comparing our approach to other state-of-the-art, domain-independent techniques. The results confirm the importance of the domain in order to build accurate opinion extraction systems. Some experiments on the influence of the dataset size and an example of aggregation and visualization of the extracted opinions are also shown