A Multilingual Spam Reviews Detection Based on Pre-Trained Word Embedding and Weighted Swarm Support Vector Machines

Online reviews are important information that customers seek when deciding to buy products or services. Also, organizations benefit from these reviews as essential feedback for their products or services. Such information required reliability, especially during the Covid-19 pandemic which showed a massive increase in online reviews due to quarantine and sitting at home. Not only the number of reviews was boosted but also the context and preferences during the pandemic. Therefore, spam reviewers reflect on these changes and improve their deception technique. Spam reviews usually consist of misleading, fake, or fraudulent reviews that tend to deceive customers for the purpose of making money or causing harm to other competitors. Hence, this work presents a Weighted Support Vector Machine (WSVM) and Harris Hawks Optimization (HHO) for spam review detection. The HHO works as an algorithm for optimizing hyperparameters and feature weighting. Three different language corpora have been used as datasets, namely English, Spanish, and Arabic in order to solve the multilingual problem in spam reviews. Moreover, pre-trained word embedding (BERT) has been applied alongside three-word representation methods (NGram-3, TFIDF, and One-hot encoding). Four experiments have been conducted, each focused on solving and demonstrating different aspects. In all experiments, the proposed approach showed excellent results compared with other state-ofthe- art algorithms. In other words, the WSVM-HHO achieved an accuracy of 88.163%, 71.913%, 89.565%, and 84.270%, for English, Spanish, Arabic, and Multilingual datasets, respectively. Further, a deep analysis has been conducted to investigate the context of reviews before and after the COVID-19 situation. In addition, it has been generated to create a new dataset with statistical features and merge its previous textual features for improving detection performance.Projects TED2021-129938B-I0,PID2020-113462RB-I00, PDC2022-133900-I00PID2020-115570GB-C22, granted by Ministerio Español de Ciencia e InnovaciónMCIN/AEI/10.13039/501100011033MCIN/AEI/10.13039/501100011033MCIN/AEINext GenerationEU/PRT

Spam Reviews Detection in the Time of COVID-19 Pandemic: Background, Definitions, Methods and Literature Analysis

This work has been partially funded by projects PID2020-113462RB-I00 (ANIMALICOS), granted by Ministerio Espanol de Economia y Competitividad; projects P18-RT-4830 and A-TIC-608-UGR20 granted by Junta de Andalucia, and project B-TIC-402-UGR18 (FEDER and Junta de Andalucia).During the recent COVID-19 pandemic, people were forced to stay at home to protect their own and others’ lives. As a result, remote technology is being considered more in all aspects of life. One important example of this is online reviews, where the number of reviews increased promptly in the last two years according to Statista and Rize reports. People started to depend more on these reviews as a result of the mandatory physical distance employed in all countries. With no one speaking to about products and services feedback. Reading and posting online reviews becomes an important part of discussion and decision-making, especially for individuals and organizations. However, the growth of online reviews usage also provoked an increase in spam reviews. Spam reviews can be identified as fraud, malicious and fake reviews written for the purpose of profit or publicity. A number of spam detection methods have been proposed to solve this problem. As part of this study, we outline the concepts and detection methods of spam reviews, along with their implications in the environment of online reviews. The study addresses all the spam reviews detection studies for the years 2020 and 2021. In other words, we analyze and examine all works presented during the COVID-19 situation. Then, highlight the differences between the works before and after the pandemic in terms of reviews behavior and research findings. Furthermore, nine different detection approaches have been classified in order to investigate their specific advantages, limitations, and ways to improve their performance. Additionally, a literature analysis, discussion, and future directions were also presented.Spanish Government PID2020-113462RB-I00Junta de Andalucia P18-RT-4830 A-TIC-608-UGR20 B-TIC-402-UGR18European Commission B-TIC-402-UGR1

Binding of the five multistate species of the anthocyanin analog 7- β -D-glucopyranosyloxy-4′-hydroxyflavylium to the β -cyclodextrin derivative captisol

The host-guest chemistry of the anthocyanin analog 7-β-D-glucopyranosyloxy-4'-hydroxyflavylium (GHF) was studied in the presence of the β-cyclodextrin derivative captisol by stopped flow, UVevisible spectroscopy, flash photolysis, circular dichroism and isothermal titration calorimetry. The equilibrium and rate constants of the multistate of chemical species derived from the flavylium ion were calculated and compared with those in the absence of the host. A new procedure to obtain the host-guest association constants of the multistate (including the transient species) by superimposing the two energy level diagrams, in the presence and absence of the cyclodextrin, was developed. The results indicate that the magnitude of the association constants follows the order, trans-chalcone = cis-chalcone = hemiketal > quinoidal base > flavylium cation. The hydration equilibrium constant increases ca. 42 times in the presence of captisol as the hydration and dehydration rate constants respectively increases and decreases. The other equilibrium constants are modestly affected: the rate constants of ring closure and opening are significantly decreased in the complex and the isomerization rate constants increase in both directions. The quantum yield of the photochromic system in the presence of captisol is0.3, i.e. 3 times higher than in the absence of the host

Making amorphous ZnO: Theoretical predictions of its structure and stability

ZnO is a transparent semiconductor with optoelectronic, thermoelectric, and sensor applications, where using amorphous thin films presents great advantages. However, growing amorphous (a) films of pure ZnO proved challenging due to their rapid crystallization. We investigated the ability of bulk ZnO to form glass structures using well-tested interatomic potentials and a melt and quench procedure within isothermal-isobaric (NPT) ensemble. The geometries of some of the resulting structures were further optimized using density functional theory (DFT) calculations with the PBE functional. We demonstrate that cooling rates in melt and quench procedure equal or exceeding 100 Kps−1 lead to formation of stable amorphous structures. However, ZnO samples tend to crystallize at lower cooling rates. This result does not depend on the size of the periodic cell used in the calculations for cells containing more than 324 atoms. Using simulation cells with up to 768 000 atoms, we demonstrate that the expected average glass density is about 5.04 gcm−3 and the coordination numbers of Zn and O atoms are around 3.9. We calculate radial distribution functions and characterize the structures of amorphous ZnO samples. Using both the activation-relaxation technique and simulated annealing, we show that the obtained amorphous structures have low propensity to crystallization

Real and virtual polymorphism of titanium selenide with robust interatomic potentials

The first successful pairwise potential for a layered material, TiSe2, has been parameterised to fit the experimental data, using a genetic algorithm as the optimisation tool for the parameters of the interatomic potential

Guidelines to bridge the gap between adaptive thermal comfort theory and building design and operation practice

Adaptive thermal comfort guidelines have been developed within the work of Annex 69: “Strategy and practice of adaptive thermal comfort in low energy buildings”. The guidelines have been established based on a framework for adopting adaptive thermal comfort principles in building design and operation developed by the authors. The guidelines target building practitioners, addressing the critical interrelated role building planners, building operators and occupants play. A successful adaptive thermal comfort design, in which design for human thermal adaptation is foreseen, planned, and carefully embedded in the design and operation intent, is based on broad knowledge and understanding of the multiple quantifiable and non-quantifiable factors influencing human perception, as well as human building interaction. Adaptive building design follows a user-centric integrated design approach and therefore it is critical to consider the occupants’ and the operators’ role in buildings already in the design phase. This paper focuses on three main challenges identified earlier and how these are addressed in the guidelines, i.e. i) updating prevailing knowledge about human thermophysiology and adaptation, ii) developing a procedure for design of adaptive opportunities, and iii) providing guidance for operational planning and operation of adaptive buildings. The challenge for future research remains to assess the magnitude of how specific design decisions affect particular adaptive mechanisms

Extension of Bogoliubov theory to quasi-condensates

We present an extension of the well-known Bogoliubov theory to treat low dimensional degenerate Bose gases in the limit of weak interactions and low density fluctuations. We use a density-phase representation and show that a precise definition of the phase operator requires a space discretisation in cells of size $l$. We perform a systematic expansion of the Hamiltonian in terms of two small parameters, the relative density fluctuations inside a cell and the phase change over a cell. The resulting macroscopic observables can be computed in one, two and three dimensions with no ultraviolet or infrared divergence. Furthermore this approach exactly matches Bogoliubov's approach when there is a true condensate. We give the resulting expressions for the equation of state of the gas, the ground state energy, the first order and second order correlations functions of the field. Explicit calculations are done for homogeneous systems.Comment: 32 pages, 2 figures; typos corrected in revised versio

The use of mesenchymal stromal cells in treatment of lung disorders

The therapeutic use of mesenchymal stromal cells (MSCs) represents a promising alternative clinical strategy for treating acute and chronic lung disorders. Several pre-clinical reports demonstrated that MSCs can secrete multiple paracrine factors and that their immunomodulatory properties can support endothelial and epithelial regeneration, modulate the inflammatory cascade, and protect lungs from damage. The effects of MSC transplantation into patients suffering from lung diseases should be fully evaluated through careful assessment of safety and associated risks, which is a prerequisite for translation of pre-clinical research into clinical practise. In this article we summarise the current status of pre-clinical research and review initial MSC-based clinical trials for treating lung injuries and lung disorders