bluuebunny/crossref_metadata_2025 huggingface dataset:
Effectiveness of Machine Learning Approaches Towards Credibility Assessment of Crowdfunding Projects for Reliable Recommendations
Authors: Shafqat Wafa , Byun Yung-Cheol , Park Namje
Published: December 2020

Recommendation systems aim to decipher user interests, preferences, and behavioral patterns automatically. However, it becomes trickier to make the most trustworthy and reliable recommendation to users, especially when their hardest earned money is at risk. The credibility of the recommendation is of magnificent importance in crowdfunding project recommendations. This research work devises a hybrid machine learning-based approach for credible crowdfunding projects’ recommendations by wisely incorporating backers’ sentiments and other influential features. The proposed model has four modules: a feature extraction module, a hybrid LDA-LSTM (latent Dirichlet allocation and long short-term memory) based latent topics evaluation module, credibility formulation, and recommendation module. The credibility analysis proffers a process of correlating project creator’s proficiency, reviewers’ sentiments, and their influence to estimate a project’s authenticity level that makes our model robust to unauthentic and untrustworthy projects and profiles. The recommendation module selects projects based on the user’s interests with the highest credible scores and recommends them. The proposed recommendation method harnesses numeric data and sentiment expressions linked with comments, backers’ preferences, profile data, and the creator’s credibility for quantitative examination of several alternative projects. The proposed model’s evaluation depicts that credibility assessment based on the hybrid machine learning approach contributes efficient results (with 98% accuracy) than existing recommendation models. We have also evaluated our credibility assessment technique on different categories of the projects, i.e., suspended, canceled, delivered, and never delivered projects, and achieved satisfactory outcomes, i.e., 93%, 84%, 58%, and 93%, projects respectively accurately classify into our desired range of credibility.
Sustainability in Italian Ceramic Tile Production: Evaluation of the Environmental Impact
Authors: Boschi Giacomo , Masi Giulia , Bonvicini Giuliana , Bignozzi Maria Chiara
Published: December 2020

Sustainable development has recently become the driving force of all the policies leading environmental, economic, and social aspects of our life. In the construction sector, a large number of technological innovations has been introduced thus leading to an assessment of the environmental impact of the production processes. In the present study, the environmental impact of the Italian ceramic tiles production is analyzed and discussed. The evolution trends of the main atmospheric pollutants and the management of water and solid wastes of ceramic tile plants have been investigated over a period greater than 10 years, considering three different layouts of production cycles. The current evaluation shows that the Italian ceramic tiles industry has considered the environmental assessment as a fundamental practice for its development since the late 1980s. The reported data prove the high level of excellence reached by the Italian ceramic tile production and demonstrate how attention to the environmental impact is a fundamental key for the ceramic tile sector.
Modeling and Control of a Cable-Suspended Sling-Like Parallel Robot for Throwing Operations
Authors: Lin Deng , Mottola Giovanni , Carricato Marco , Jiang Xiaoling
Published: December 2020

Cable-driven parallel robots can provide interesting advantages over conventional robots with rigid links; in particular, robots with a cable-suspended architecture can have very large workspaces. Recent research has shown that dynamic trajectories allow the robot to further increase its workspace by taking advantage of inertial effects. In our work, we consider a three-degrees-of-freedom parallel robot suspended by three cables, with a point-mass end-effector. This model was considered in previous works to analyze the conditions for dynamical feasibility of a trajectory. Here, we enhance the robot’s capabilities by using it as a sling, that is, by throwing a mass at a suitable time. The mass is carried at the end-effector by a gripper, which releases the mass so that it can reach a given target point. Mathematical models are presented that provide guidelines for planning the trajectory. Moreover, results are shown from simulations that include the effect of cable elasticity. Finally, suggestions are offered regarding how such a trajectory can be optimized.
A Hands-On Laboratory for Intelligent Control Courses
Authors: Torres-Salinas Hugo , Rodríguez-Reséndiz Juvenal , Estévez-Bén Adyr A. , Cruz Pérez M. A. , Sevilla-Camacho P. Y. , Perez-Soto Gerardo I.
Published: December 2020

This research focused on developing a methodology that facilitates the learning of control engineering students, specifically developing skills to design a complete control loop using fuzzy logic. The plant for this control loop is a direct current motor, one of the most common actuators used by educational and professional engineers. The research was carried out on a platform developed by a group of students. Although the learning techniques for the design and implementation of controllers are extensive, there has been a delay in teaching techniques that are relatively new compared to conventional control techniques. Then, the hands-on laboratory offers a tool for students to acquire the necessary skills in driver tuning. In addition to the study of complete systems, the ability to work in a team is developed, a fundamental skill in the professional industrial area. A qualitative and quantitative analysis of student learning was carried out, integrating a multidisciplinary project based on modern tools.
Effect of End-Effector Compliance on Collisions in Robotic Teleoperation
Authors: Tommasino Domenico , Cipriani Giulio , Doria Alberto , Rosati Giulio
Published: December 2020

In robotic teleoperation, hard impacts between a tool and the manipulated object may impair the success of a task. In order to develop a robotic system that is able to minimize the final velocity of an object after impact, a comprehensive approach is adopted in this work, and the effect on the impact of the parameters of the tool and of the robot is studied. Mass, contact stiffness and damping, robot compliance and control and tool compliance are taken into account. A mathematical model including the tool and the robot moving along the approach direction shows that, in most conditions, robot compliance is not enough to mitigate the impact. A mechanical decoupling between the inertia of the tool and the inertia of the robot is needed. An elastic system based on a bi-stable mechanism is developed and its validity is shown by means of numerical simulations.
Theoretical Analysis of Fractional Viscoelastic Flow in Circular Pipes: Parametric Study
Authors: Gritsenko Dmitry , Paoli Roberto
Published: December 2020

Pipe flow is one of the most commonly used models to describe fluid dynamics. The concept of fractional derivative has been recently found very useful and much more accurate in predicting dynamics of viscoelastic fluids compared with classic models. In this paper, we capitalize on our previous study and consider space-time dynamics of flow velocity and stress for fractional Maxwell, Zener, and Burgers models. We demonstrate that the behavior of these quantities becomes much more complex (compared to integer-order classical models) when adjusting fractional order and elastic parameters. We investigate mutual influence of fractional orders and consider their limiting value combinations. Finally, we show that the models developed can be reduced to classical ones when appropriate fractional orders are set.
Assessment of Dietary Exposure and Risk of DDT Concerning Freshwater Fish Aquaculture
Authors: Kasza Gyula , Izsó Tekla , Csenki Eszter Zita , Micsinai Adrienn , Nyirő-Fekete Brigitta , Urbányi Béla , Alpár Boglárka
Published: December 2020

Pesticides may accumulate in freshwater fish due to contamination from the environment. This paper reports on a risk assessment of DDT and DDT metabolites in carp. A survey was conducted about dietary habits among fish consumers. Cluster analysis was accomplished based on the frequency and amount of carp consumption. Classical and carcinogenic risk assessments were performed for the clusters. While DDT contamination was present, it was not found to be risky concerning the complete diet of the clusters (carcinogenic risk was also negligible), moreover, carp consumption did not contribute significantly to the risk level even in the case of the extreme consumers.
Kinetics of Hyaluronidase Inhibition by Rice (Oryza sativa L.) Protein Hydrolysate
Authors: Chen Hui-Ju , Dai Fan-Jhen , Fan Siao-Ling , Huang Yu-Chun , Chau Chi-Fai , Lin Yung-Sheng , Chen Chin-Shuh
Published: December 2020

Research on the skin’s maintenance and protection against aging has gradually progressed toward phytocosmetics. This study investigated the in vitro hyaluronidase inhibitory activity of rice protein hydrolysate obtained by using bacterial amylase and protease against skin aging-related enzymes. Here, the molecular weights of rice protein hydrolysates were in the range 5–63 kDa. Every 100 g of a rice protein hydrolysate contains approximately 2960 mg of total amino acid, including essential amino acids (893 mg) and branched-chain amino acids (591 mg). A kinetic study showed that hyaluronidase inhibition by the rice protein hydrolysate occurs through a competitive reaction mechanism. Achieving effective hyaluronidase inhibitory activity, the rice protein hydrolysate had a half maximal inhibitory concentration of 7.61 mg/mL. Because hyaluronidase activity inhibition is crucial for treating skin aging, rice protein hydrolysates should be considered as cosmeceutical ingredients.
Computer Aided Modeling of Wood Chips Transport by Means of a Belt Conveyor with Use of Discrete Element Method
Authors: Gierz Łukasz , Warguła Łukasz , Kukla Mateusz , Koszela Krzysztof , Zwiachel Tomasz Szymon
Published: December 2020

The effectiveness and precision of transporting wood chips on the transport trailer or hopper depends on an inclination angle, a conveyor belt speed, and length. In order to devise a methodology aiding designing and the selection of technical and performance parameters (aiding the settings of conveyor belt sub-assemblies), the authors carried out the simulation tests concerning wood chips transport on the belt conveyor and their outlet. For the purposes of these tests, a simulation model was performed in the Rocky DEM (discrete element method) software in the numerical analysis environment and compared to analytical tests. The tested wood chips were taken from cherry plum branches chipping processes (Prunus cerasifera Ehrh. Beitr. Naturk. 4:17. 1789 (Gartenkalender 4:189-204. 1784)), out of which seven basic fractions were separated, which differed mainly in terms of their diameter from 5 mm to 50 mm and the length of 150 mm. The article presents the results of wood chips ejection distance in the form of the 3D functions of wood chips ejection distance depending on the conveyor belt inclination angle and belt speed. The results are presented for five conveyor belt lengths (1 m, 2 m, 3 m, 4 m, 5 m). The tests also involved the conveyor belt inclination angle in the range from 10° to 50° and the belt velocity in the range from 1 m/s2 to 5 m/s2. The numerical test results demonstrate higher average values of wood chips ejection distance than designated in the analytical model. The average arithmetical difference in the results between the numerical and analytical model is at the level of 13%.
Electrical and Meteorological Data Acquisition System of a Commercial and Domestic Microgrid for Monitoring PV Parameters
Authors: Meyer Edson L. , Apeh Oliver O. , Overen Ochuko K.
Published: December 2020

This paper centers on the design and installation of a robust photovoltaic (PV)-based microgrid data acquisition system (DAS) that can monitor different PV systems simultaneously. The PV-based microgrid consists of three solar systems: off-grid, hybrid and grid-assisted systems, each with 3.8 kWp located at SolarWatt park, Fort Hare Institute of Technology (FHIT), South Africa. The designed DAS is achieved by assembling and connecting a set of sensors to measure and log electrical and meteorological parameters from each of the three power plants. Meteorological parameters use a CR1000 datalogger while the electrical output parameters use a DT80 data logger. Calibration was done by voltage signal conditioning which helps to reduce errors initiated by analogue signals. The designed DAS mainly assist in assessing the potential of solar energy of the microgrid power plant considering the energy needed in the remote community. Besides, the simultaneous monitoring of the three systems ensures that the outdoor operating conditions are the same while comparing the logged data. A variable day and a week, data were used to verify the reliability of the system. The back of the array temperature was observed to be 42.7 °C when solar irradiance was 1246 W/m2. The ambient temperature and relative humidity were obtained at 21.3 °C and 63.3%, respectively. The PV current in all three systems increases with the solar irradiance and is highest around midday. The results obtained show that the designed DAS is of great interest in PV system developments.
Broad UV Emission Lines in Type-1 Active Galactic Nuclei: A Note on Spectral Diagnostics and the Excitation Mechanism
Authors: Marziani Paola , del Olmo Ascension , Perea Jaime , D’Onofrio Mauro , Panda Swayamtrupta
Published: December 2020

This paper reviews several basic emission properties of the UV emission lines observed in the spectra of quasars and type-1 active galactic nuclei, mainly as a function of the ionization parameter, metallicity, and density of the emitting gas. The analysis exploits a general-purpose 4D array of the photoionization simulations computed using the code CLOUDY, covering ionization parameter in the range 10−4.5–10+1.0, hydrogen density nH∼107–1014 cm−3, metallicity Z between 0.01 and 100 Z⊙, and column density in the range 1021–1023 cm−2. The focus is on the most prominent UV emission lines observed in quasar spectra, namely Nvλ1240, Siivλ1397, Oiv]λ1402, Civλ1549, Heiiλ1640, Aliiiλ1860, Siiii]λ1892, and Ciii]λ1909, and on the physical conditions under which electron-ion impact excitation is predicted to be the dominant line producer. Photoionization simulations help constrain the physical interpretation and the domain of applicability of spectral diagnostics derived from measurements of emission line ratios, reputed to be important for estimating the ionization degree, density, and metallicity of the broad line emitting gas, as well as the relative intensity ratios of the doublet or multiplet components relevant for empirical spectral modeling.
Epidemic Dynamics via Wavelet Theory and Machine Learning with Applications to Covid-19
Authors: Tat Dat Tô , Frédéric Protin , Hang Nguyen T. T. , Jules Martel , Duc Thang Nguyen , Piffault Charles , Willy Rodríguez , Susely Figueroa , Lê Hông Vân , Tuschmann Wilderich , Tien Zung Nguyen
Published: December 2020

We introduce the concept of epidemic-fitted wavelets which comprise, in particular, as special cases the number I(t) of infectious individuals at time t in classical SIR models and their derivatives. We present a novel method for modelling epidemic dynamics by a model selection method using wavelet theory and, for its applications, machine learning-based curve fitting techniques. Our universal models are functions that are finite linear combinations of epidemic-fitted wavelets. We apply our method by modelling and forecasting, based on the Johns Hopkins University dataset, the spread of the current Covid-19 (SARS-CoV-2) epidemic in France, Germany, Italy and the Czech Republic, as well as in the US federal states New York and Florida.
Effects of Propranolol on Growth, Lipids and Energy Metabolism and Oxidative Stress Response of Phaeodactylum tricornutum
Authors: Duarte Bernardo , Feijão Eduardo , Cruz de Carvalho Ricardo , Duarte Irina A. , Silva Marisa , Matos Ana Rita , Cabrita Maria Teresa , Novais Sara C. , Lemos Marco F. L. , Marques João Carlos , Caçador Isabel , Reis-Santos Patrick , Fonseca Vanessa F.
Published: December 2020

Present demographic trends suggest a rise in the contributions of human pharmaceuticals into coastal ecosystems, underpinning an increasing demand to evaluate the ecotoxicological effects and implications of drug residues in marine risk assessments. Propranolol, a non-selective β-adrenoceptor blocker, is used worldwide to treat high blood pressure conditions and other related cardiovascular conditions. Although diatoms lack β-adrenoceptors, this microalgal group presents receptor-like kinases and proteins with a functional analogy to the animal receptors and that can be targeted by propranolol. In the present work, the authors evaluated the effect of this non-selective β-adrenoceptor blocker in diatom cells using P. tricornutum as a model organism, to evaluate the potential effect of this compound in cell physiology (growth, lipids and energy metabolism and oxidative stress) and its potential relevance for marine ecosystems. Propranolol exposure leads to a significant reduction in diatom cell growth, more evident in the highest concentrations tested. This is likely due to the observed impairment of the main primary photochemistry processes and the enhancement of the mitochondrial respiratory activity. More specifically, propranolol decreased the energy transduction from photosystem II (PSII) to the electron transport chain, leading to an increase in oxidative stress levels. Cells exposed to propranolol also exhibited high-dissipated energy flux, indicating that this excessive energy is efficiently diverted, to some extent, from the photosystems, acting to prevent irreversible photoinhibition. As energy production is impaired at the PSII donor side, preventing energy production through the electron transport chain, diatoms appear to be consuming storage lipids as an energy backup system, to maintain essential cellular functions. This consumption will be attained by an increase in respiratory activity. Considering the primary oxygen production and consumption pathways, propranolol showed a significant reduction of the autotrophic O2 production and an increase in the heterotrophic mitochondrial respiration. Both mechanisms can have negative effects on marine trophic webs, due to a decrease in the energetic input from marine primary producers and a simultaneous oxygen production decrease for heterotrophic species. In ecotoxicological terms, bio-optical and fatty acid data appear as highly efficient tools for ecotoxicity assessment, with an overall high degree of classification when these traits are used to build a toxicological profile, instead of individually assessed.
A Comparative View on the Oviductal Environment during the Periconception Period
Authors: González-Brusi Leopoldo , Algarra Blanca , Moros-Nicolás Carla , Izquierdo-Rico Mª José , Avilés Manuel , Jiménez-Movilla Maria
Published: December 2020

The oviduct plays important roles in reproductive events: sperm reservoir formation, final gamete maturation, fertilization and early embryo development. It is well known that the oviductal environment affects gametes and embryos and, ultimately, the health of offspring, so that in vivo embryos are better in terms of morphology, cryotolerance, pregnancy rates or epigenetic profile than those obtained in vitro. The deciphering of embryo–maternal interaction in the oviduct may provide a better understanding of the embryo needs during the periconception period to improve reproductive efficiency. Here, we perform a comparative analysis among species of oviductal gene expression related to embryonic development during its journey through the oviduct, as described to date. Cross-talk communication between the oviduct environment and embryo will be studied by analyses of the secreted or exosomal proteins of the oviduct and the presence of receptors in the membrane of the embryo blastomeres. Finally, we review the data that are available to date on the expression and characterization of the most abundant protein in the oviduct, oviductin (OVGP1), highlighting its fundamental role in fertilization and embryonic development.
DNA–Gold Nanozyme-Modified Paper Device for Enhanced Colorimetric Detection of Mercury Ions
Authors: Mao Min-Xin , Zheng Rong , Peng Chi-Fang , Wei Xin-Lin
Published: December 2020

In this work, a paper device consisted of a patterned paper chip, wicking pads, and a base was fabricated. On the paper chip, DNA–gold nanoparticles (DNA–AuNPs) were deposited and Hg2+ ions could be adsorbed by the DNA–AuNPs. The formed DNA–AuNP/Hg2+ nanozyme could catalyze the tetramethylbenzidine (TMB)–H2O2 chromogenic reaction. Due to the wicking pads, a larger volume of Hg2+ sample could be applied to the paper device for Hg2+ detection and therefore the color response could be enhanced. The paper device achieved a cut-off value of 50 nM by the naked eye for Hg2+ under optimized conditions. Moreover, quantitative measurements could be implemented by using a desktop scanner and extracting grayscale values. A linear range of 50–2000 nM Hg2+ was obtained with a detection limit of 10 nM. In addition, the paper device could be applied in the detection of environmental water samples with high recoveries ranging from 85.7% to 105.6%. The paper-device-based colorimetric detection was low-cost, simple, and demonstrated high potential in real-sample applications.
Seismic Design of Grana Cheese Cold-Formed Steel Racks
Authors: Bernuzzi Claudio , Simoncelli Marco
Published: December 2020

Since few years ago only one typology of racks was used to store Grana cheese wheels for aging, which was designed focusing on the sole static behavior. Battened steel columns made by vertical tubes welded to horizontal angles were connected by means of wood boards supporting the wheels. In 2012, a strong earthquake occurred in Emilia Romagna (Italy) and a great number of these structures collapsed owing to the absence of checks for resistance against earthquakes. This catastrophic event plus the need to maximize the structural efficiency led to the development of a new typology of rack systems based on the use of cold-formed steel members. Owing to an extremely limited state-of-the-art on these modern cheese rack, design is carried out in agreement with the standard provisions calibrated and proposed for adjustable pallet racks, despite the non-negligible differences between these structural systems. The paper is focused on the comparison between the available seismic design approaches for cheese rack in order to highlight their main advantages and limits. In particular, among the four design approaches admitted in the European standards, the modal response spectrum analysis (MRSA) and the nonlinear time-history (NLTH) have been considered and the associated results compared in terms of maximum safety index of the members, global displacements and interstorey drifts. Research outcomes stress the differences associated with the considered approaches in terms of expected performance underlining the importance of an accurate definition of the behavior (q-) factor.
Seismic Vulnerability of Masonry Lighthouses: A Study of the Bengut Lighthouse, Dellys, Boumerdès, Algeria
Authors: Amari Karima , Abdessemed Foufa Amina , Cheikh Zouaoui Mustapha , Uva Giuseppina
Published: December 2020

In Algeria, lighthouses are an essential element of the maritime landscape and constitute a substantial part of the local historical and cultural heritage, marked by a great variety of styles, architecture, geometrical forms, and materials. The study presented falls into the general context of pre- and post-seismic conservation of Algerian lighthouses, since all these stone masonry buildings are situated in areas characterized by a medium–high seismic hazard. In the paper, a relevant example has been analyzed: the Bengut Lighthouse, which has been classified as “National Heritage” by the Algerian Ministry of Culture and has been severely damaged by the Boumerdès that occurred on 21 May 2003. After an overview of historical lighthouses in Algeria and their morpho-typological classification, the case study of the lighthouse at Cap Bengut is presented, showing the results of a detailed survey of the geometric and constructive features and of the actual cracking and damage pattern. First, based on the critical analysis of this knowledge framework, a preliminary qualitative evaluation of the seismic vulnerability has been made, analyzing and classifying the set of local and global failure modes coherently with the observed structural pathologies and damages. Then, numerical modeling has been implemented in TreMuri computer code, performing a set of pushover analyses. This allowed the investigation of the criticalities in the response of the building to seismic actions, characterization of the dynamic behavior, and comparison with the actual observed damages, which are discussed, providing an interpretation of the global and local failure modes. Based on the results of the visual assessment and numerical analysis, guidelines for the retrofitting intervention have been proposed, by considering, on the one hand, the objective of effectively mitigating the elements of vulnerability pointed out by the results and, on the other, the main principles of conservation and restoration. The presented study and its results, in perspective, are intended to provide a basis for developing risk and vulnerability analysis of typological classes of historical lighthouses at a large scale.
A CO2-Mediated Conjugate Cyanide Addition to Chalcones
Authors: Dotzauer Simon , Hadaf Gul Barg , Kamounah Fadhil S. , Kadziola Anders , Lee Ji-Woong
Published: December 2020

Carbon dioxide is an intrinsically stable molecule; however, it can readily react with various nucleophilic reagents. In the presence of a cyanide source, CO2 was proven to be useful to promote addition reactions. Here we report the use of CO2 to facilitate 1,4-conjugate cyanide addition reaction to chalcones to generate organonitriles. Nitriles are key component in organic synthesis due to their utility in numerous functional group transformation, however, conjugation addition of cyanide has been a challenge in this substrate class due to side reactions. To mitigate this, we employed simple ammonium and metal cyanide sources as nucleophiles under carbon dioxide atmosphere where high selectivity toward the desired product was obtained. The presented reaction is not feasible under inert atmosphere, which highlights the important role of CO2, as a Lewis and Brøndsted acidic catalyst. Further derivatization of organonitriles compounds were performed to showcase the utility of the reaction, while an unprecedented dimerization reaction was identified and characterized, affording a cyclopentanone scaffold.
SnSe2-Zn-Porphyrin Nanocomposite Thin Films for Threshold Methane Concentration Detection at Room Temperature
Authors: Lőrinczi Adam , Fagadar-Cosma Eugenia , Socol Gabriel , Mihăilescu Andreea , Matei Elena , Sava Florinel , Ştefan Mariana
Published: December 2020

Nanocomposite thin films, sensitive to methane at the room temperature (25–30 °C), have been prepared, starting from SnSe2 powder and Zn(II)-5,10,15,20-tetrakis-(4-aminophenyl)- -porphyrin (ZnTAPP) powder, that were fully characterized by XRD, UV-VIS, FT-IR, Nuclear Magnetic Resonance (1H-NMR and 13C-NMR), Atomic Force Microscopy (AFM), SEM and Electron Paramagnetic Resonance (EPR) techniques. Film deposition was made by drop casting from a suitable solvent for the two starting materials, after mixing them in an ultrasonic bath. The thickness of these films were estimated from SEM images, and found to be around 1.3 μm. These thin films proved to be sensitive to a threshold methane (CH4) concentration as low as 1000 ppm, at a room temperature of about 25 °C, without the need for heating the sensing element. The nanocomposite material has a prompt and reproducible response to methane in the case of air, with 50% relative humidity (RH) as well. A comparison of the methane sensing performances of our new nanocomposite film with that of other recently reported methane sensitive materials is provided. It is suitable for signaling gas presence before reaching the critical lower explosion limit concentration of methane at 50,000 ppm.
An Interactive Serious Mobile Game for Supporting the Learning of Programming in JavaScript in the Context of Eco-Friendly City Management
Authors: Maskeliūnas Rytis , Kulikajevas Audrius , Blažauskas Tomas , Damaševičius Robertas , Swacha Jakub
Published: December 2020

In the pedagogical process, a serious game acts as a method of teaching and upbringing, the transfer of accumulated experience and knowledge. In this paper, we describe an interactive serious programming game based on game-based learning for teaching JavaScript programming in an introductory course at university. The game was developed by adopting the gamification pattern-based approach. The game is based on visualizations of different types of algorithms, which are interpreted in the context of city life. The game encourages interactivity and pursues deeper learning of programming concepts. The results of the evaluation of the game using pre-test and post-test knowledge assessment, the Technology Acceptance Model (TAM), and the Technology-Enhanced Training Effectiveness Model (TETEM) are presented.
Nonlinear Dynamics and Entropy of Complex Systems with Hidden and Self-Excited Attractors II
Authors: Volos Christos K. , Jafari Sajad , Munoz-Pacheco Jesus M. , Kengne Jacques , Rajagopal Karthikeyan
Published: December 2020

According to the pioneering work of Leonov and Kuznetsov [...]
Features of Known and Unknown Words for First Graders of Different Proficiency Levels in Winter and Spring
Authors: Hiebert Elfrieda H. , Toyama Yukie , Irey Robin
Published: December 2020

This study describes the features of words known and unknown by first graders of different proficiency levels in six instances of an oral reading fluency assessment: three in winter and three in spring. A sample of 411 students was placed into four groups (very high, high, middle, and low) based on their median correct words per minute in spring. Each word in the assessment was coded on 11 features: numbers of phonemes, letters, syllables, blends, morphemes, percentages of multisyllabic and of morphologically complex words, concreteness, age of acquisition, decodability, and U function. Words were classified as known if more than 50% of the students within a group were able to correctly read those words. Features of known and unknown words were contrasted for all but the highest group, which made no errors, at each point in time. An analysis of the patterns of known words across groups from winter to spring shows that students followed a similar general progression in the number and type of words recognized. The most prominent feature of unknown words in winter and spring for the middle group of students was the presence of multiple syllables. The lowest-performing group of students continued to be limited by word length and frequency in their recognition of words, but on both features, their proficiency increased from winter to spring. The discussion addresses several critical issues, most notably the relationship of words in oral reading assessments to the word recognition curriculum of many beginning reading programs.
Impact of Contextual Predictors on Value-Added Teacher Effectiveness Estimates
Authors: Aslantas Ismail
Published: December 2020

It is widely believed that the teacher is one of the most important factors influencing a student’s success at school. In many countries, teachers’ salaries and promotion prospects are determined by their students’ performance. Value-added models (VAMs) are increasingly used to measure teacher effectiveness to reward or penalize teachers. The aim of this paper is to examine the relationship between teacher effectiveness and student academic performance, controlling for other contextual factors, such as student and school characteristics. The data are based on 7543 Grade 8 students matched with 230 teachers from one province in Turkey. To test how much progress in student academic achievement can be attributed to a teacher, a series of regression analyses were run including contextual predictors at the student, school and teacher/classroom level. The results show that approximately half of the differences in students’ math test scores can be explained by their prior attainment alone (47%). Other factors, such as teacher and school characteristics explain very little the variance in students’ test scores once the prior attainment is taken into account. This suggests that teachers add little to students’ later performance. The implication, therefore, is that any intervention to improve students’ achievement should be introduced much earlier in their school life. However, this does not mean that teachers are not important. Teachers are key to schools and student learning, even if they are not differentially effective from each other in the local (or any) school system. Therefore, systems that attempt to differentiate “effective” from “ineffective” teachers may not be fair to some teachers.
Design, Analysis, and Implementation of an Equalizer Circuit for the Elimination of Voltage Imbalance in a Half-Bridge Boost Converter with Power Factor Correction
Authors: Bayona Jhon , Gélvez Nancy , Espitia Helbert
Published: December 2020

For the implementation of a boost converter, the half-bridge topology provides a simpler conversion circuit; however, the voltage imbalance between the capacitors is a critical factor since traditional control methodology decreases the power factor when correcting the imbalance. Consequently, this paper proposes a circuit to correct such imbalance keeping the power factor at the same time. Then, this work carries the analysis, simulation, and implementation of a strategy to reduce voltage imbalance in a half-bridge boost converter with correction of the power factor. The first part offers a description of the equalizer circuit; then, an average model is employed to perform the mathematical analysis. Later, a comparison via simulation is undertaken including other conventional converters in different scenarios. Moreover, an experimental laboratory setup is made; the results show that the equalizer circuit reduces voltage imbalance between the capacitors in a half-bridge booster converter.
The Detection of Black Ice Accidents for Preventative Automated Vehicles Using Convolutional Neural Networks
Authors: Lee Hojun , Kang Minhee , Song Jaein , Hwang Keeyeon
Published: December 2020

Automated Vehicles (AVs) are expected to dramatically reduce traffic accidents that have occurred when using human driving vehicles (HVs). However, despite the rapid development of AVs, accidents involving AVs can occur even in ideal situations. Therefore, in order to enhance their safety, “preventive design” for accidents is continuously required. Accordingly, the “preventive design” that prevents accidents in advance is continuously required to enhance the safety of AVs. Specially, black ice with characteristics that are difficult to identify with the naked eye—the main cause of major accidents in winter vehicles—is expected to cause serious injuries in the era of AVs, and measures are needed to prevent them. Therefore, this study presents a Convolutional Neural Network (CNN)-based black ice detection plan to prevent traffic accidents of AVs caused by black ice. Due to the characteristic of black ice that is formed only in a certain environment, we augmented image data and learned road environment images. Tests showed that the proposed CNN model detected black ice with 96% accuracy and reproducibility. It is expected that the CNN model for black ice detection proposed in this study will contribute to improving the safety of AVs and prevent black ice accidents in advance.
Development of a Portable Multi-Sensor Urine Test and Data Collection Platform for Risk Assessment of Kidney Stone Formation
Authors: Chung Wen-Yaw , Falah Ramezani Roozbeh , A. Silverio Angelito , F. Tsai Vincent
Published: December 2020

In this paper, we present an Internet of things (IoT)-based data collection system for the risk assessment of urinary stone formation, or urolithiasis, by the measurement and storage of four parameters in urine: pH, concentrations of ionized calcium (Ca2+), uric acid and total dissolved solids. The measurements collected by the system from patients and healthy individuals grouped by age and gender will be stored in a cloud database. These will be used in the training phase of an artificial intelligence (AI) machine learning process utilizing the logistics regression model. The trained model provides a binary risk assessment, indicating if the end user is either a stone-former or not. For system validation, standard chemical solutions were used. Preliminary results indicated a sufficient measurement range, falling within the physiological range, and resolution for pH (2.0–10.0, +/−0.1), Ca2+(0.1–3.0 mmol/l, +/−0.05), uric acid (20–500 ppm, +/−1) and conductivity (1.0–40.0 mS/cm, +/−0.1), exhibiting high correlation with standard instruments. We intend to deploy this system in few hospitals in Taiwan to collect the data of patients’ urine, with analysis aided by urologist assessments for the risk of urolithiasis. The modularized design allows future modification and expansion to accommodate other sensing analytes.
Real-Time Mode Switching and Beam Scanning of High-Gain OAM Waves Using a 1-Bit Reconfigurable Reflectarray Antenna
Authors: Wang Ziyang , Pan Xiaotian , Yang Fan , Xu Shenheng , Li Maokun
Published: December 2020

A reconfigurable electromagnetic surface has been studied to realize the adjustable orbital angular momentum (OAM) beams for real-time wireless communication and dynamic target detection in the future. OAM mode switching realized by many previous designs suffers from low gains without OAM beam scanning. In this article, a 1-bit reconfigurable reflectarray antenna is designed, fabricated, and tested for the real-time control of OAM mode switching and large-angle vortex beam scanning in three-dimensional space. The proposed reflectarray surface is composed of 1-bit electronically reconfigurable cells, and the size is 24 λ × 24 λ with 2304 units. The reconfigurable element is designed by using a radiation patch loading a PIN diode with effective control of two states, “ON” and “OFF”, for the demand of 180° phase difference. The reflectarray surface can be assigned to a code sequence of 0 or 1 by the Field-Programmable Gate Array (FPGA) in real time. Henceforth, the coding surface can dynamically control the generation of high-gain OAM beams, where only the optimized phase distributions on the surface need to be changed according to demand. To verify the concept, a large-scale reflectarray surface is fabricated and measured with an oblique feed at 15°. Different OAM-carrying phase distributions for different OAM beam states are calculated and tested. The test results show that the OAM mode switching between l = 1 and l = 2 is realized, and other variable modes such as l = 3 or l = 5 can also be achieved by modifying the phase encoding sequence. Furthermore, the direction of the vortex beams can be accurately controlled with gains over 20 dBi, and the large-angle vortex beam scanning is verified. Therefore, all results demonstrate that the proposed 1-bit reconfigurable reflectarray is efficient for the regulation and control of OAM-carrying beams for the demand of real-time dynamic wireless communications in the future.
Wavelet Transform Analysis of Heart Rate to Assess Recovery Time for Long Distance Runners
Authors: Redlarski Grzegorz , Siebert Janusz , Krawczuk Marek , Zak Arkadiusz , Danilowicz-Szymanowicz Ludmila , Dolinski Lukasz , Gutknecht Piotr , Trzeciak Bartosz , Ratkowski Wojciech , Palkowski Aleksander
Published: December 2020

The diagnostics of the condition of athletes has become a field of special scientific interest and activity. The aim of this study was to verify the effect of a long (100 km) run on a group of runners, as well as to assess the recovery time that is required for them to return to the pre-run state. The heart rate (HR) data presented were collected the day before the extreme physical effort, on the same day as, but after, the physical effort, as well as 24 and 48 h after. The Wavelet Transform (WT) and the Wavelet-based Fractal Analysis (WBFA) were implemented in the analysis. A tool was constructed that, based on quantitative data, enables one to confirm the completion of the recovery process that is related to the extreme physical effort. Indirectly, a tool was constructed that enables one to confirm the completion of the recovery process. The obtained information proves that the return to the resting state of the body after a significant physical effort can be observed after two days entirely through the analysis of the HR. Certain practical measures were used to differentiate between two substantially different states of the human body, i.e., pre- and post-effort states were constructed. The obtained results allow for us to state that WBFA appears to be a useful and robust tool in the determination of hidden features of stochastic signals, such as HR time signals. The proposed method allows one to differentiate between particular days of measurements with a mean probability of 92.2%.
A Fully Integrated Clocked AC-DC Charge Pump for Mignetostrictive Vibration Energy Harvesting
Authors: Kawauchi Hayato , Tanzawa Toru
Published: December 2020

This paper describes a clocked AC-DC charge pump to enable full integration of power converters into a sensor or radio frequency (RF) chip even with low open circuit voltage magnetostrictive vibration energy transducer operating at a low resonant frequency of 10 Hz to 1 kHz. The frequency of the clock to drive an AC-DC charge pump was up-converted with an on-chip oscillator to increase output power of the charge pump without significantly increasing the circuit area. A model of the system including the charge pump and vibration energy transducer is shown. It was validated by HSPICE simulation and measured, resulting in a prototype chip with an area of 0.11 mm2 fabricated in a 65 nm 1 V CMOS process. The fabricated charge pump was also measured together with a magnetostrictive transducer. The charge pump converted the power from the transducer to an output power of 4.2 μW at an output voltage of 2.0 V. The output power varied below 3% over a wide input frequency of 10 Hz to 100 kHz, which suggests that universal design of the clocked AC-DC charge pump can be used for transducers with different resonant frequencies. In a low-input voltage region below 0.8 V, the proposed circuit has higher output power compared with the conventional circuits.
Assessing the Exergetic and Inherent Safety Performance of a Shrimp-Based Biorefinery via Computer-Aided Tools
Authors: Moreno-Sader Kariana Andrea , Martínez-Consuegra Jairo David , González-Delgado Ángel Darío
Published: December 2020

Although shrimp processing wastes have been studied as source of high-value products at lab-scale, no contributions are found in the literature regarding the energetic and safety performance of shrimp-based biorefineries at pilot or large-scale. This works is focused on the inherent safety assessment and exergy analysis of a pilot-scale biorefinery designed to produce shrimp meat and four by-products: chitin, chitosan, nitrogenous extract, and astaxanthin. Total irreversibilities, exergy losses, exergy of wastes and utilities were calculated for stages and the overall process using mass and energy balances of the biorefinery. The hazards associated with chemicals and process conditions were analyzed through substance properties and process data. A Numerical Descriptive Inherent Safety Technique (NuDIST) score of 557.23 suggested a moderate level of risk for the biorefinery compared to other processes, reaching chemical and process safety scores of 185.88 and 371.35, respectively. Sections (b) and (c) were identified as major hotspots from a safety point of view. The overall exergy efficiency was quantified at 25.61%, which is higher than the chitosan-from-exoskeleton linear production chain (4.58%). The highest exergy losses were found on stages as deacetylation, fresh shrimp washing and deproteinization stages. The beheading stage most contributed to irreversibilities, with 98.315%, followed by sorting, with 1.653%. These results could identify opportunities for improvement from an exergy and safety point of view by mapping less efficient and hazardous stages.
Irradiation Flux Modelling for Thermal–Electrical Simulation of CubeSats: Orbit, Attitude and Radiation Integration
Authors: Filho Edemar Morsch , Seman Laio Oriel , Rigo Cezar Antônio , Nicolau Vicente de Paulo , Ovejero Raúl García , Leithardt Valderi Reis Quietinho
Published: December 2020

During satellite development, engineers need to simulate and understand the satellite’s behavior in orbit and minimize failures or inadequate satellite operation. In this sense, one crucial assessment is the irradiance field, which impacts, for example, the power generation through the photovoltaic cells, as well as rules the satellite’s thermal conditions. This good practice is also valid for CubeSat projects. This paper presents a numerical tool to explore typical irradiation scenarios for CubeSat missions by combining state-of-the-art models. Such a tool can provide the input estimation for software and hardware in the loop analysis for a given initial condition and predict it along with the satellite’s lifespan. Three main models will be considered to estimate the irradiation flux over a CubeSat, namely an orbit, an attitude, and a radiation source model, including solar, albedo, and infrared emitted by the Earth. A case study illustrating the tool’s abilities is presented for a typical CubeSats’ two-line element set (TLE) and five attitudes. Finally, a possible application of the tool as an input to a CubeSat task-scheduling is introduced. The results show that the complete model’s use has considerable differences from the simplified models sometimes used in the literature.
Analysis of the Influence of Reducing the Duration of a Thermal Response Test in a Water-Filled Geothermal Borehole Located in Spain
Authors: Nieto Ignacio , Blázquez Cristina , Martín Arturo , González-Aguilera Diego
Published: December 2020

Usually thermal response tests are restricted to big geothermal projects; the high investment makes them less suitable for designing domestic low-enthalpy geothermal energy systems. The work here presented aims to study the influence of time reduction in thermal response tests on their precision. Due to the importance of the correct assessment of the thermal characterization of the ground for any kind of geothermal system, time reduction in this essay could make it more affordable to be implemented in some domestic systems. A thermal response test has been implemented, and several time intervals of the test have been considered in order to obtain different results for the thermal conductivity of the ground. The mentioned results have been then compared and also the domestic geothermal systems designed from them by the use of the geothermal software GES-CAL. Results have shown that, in some cases (our testing borehole has some singular characteristics), a significant time reduction in the data acquisition process of the thermal response test does not compromise seriously the precision of the results.