bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of the Low-Frequency Error of the Residual Orbit on Recovering Time-Variable Gravity Field from the Satellite-To-Satellite Tracking Mission
Authors: Liang Lei , Yu Jinhai , Wang Changqing , Zhong Min , Feng Wei , Wan Xiaoyun , Chen Wei , Yan Yihao
Published: March 2021

When using the dynamic approach to recover the time-variable gravity field, the reference orbit generated by the perturbation model and the non-conservative force observed from the accelerometer should be introduced at first, and then the observation equations of the residual orbit and the residual range rate are established. This introduces a perturbation model error and instrument noise. Thus, there are low-frequency errors in the residual orbit and the residual range rate. Currently, most studies only focus on the low-frequency error of the residual range rate, neglecting the influence of the low-frequency error in the residual orbit. Therefore, under the condition of the perturbation model error and instrument noise including the constant term and 1CPR term, the low-frequency error formulas of the residual orbit and residual range rate are derived according to the characteristics of the solution of the Hill equation. Then, the influence of the low-frequency error on the residuals is analyzed by using the simulation and the real data processing respectively. In the simulation and real data processing, the accuracy of the recovered gravity field can maintain a good consistency for different arc lengths by removing the low-frequency error in the residual orbit. Finally, the time-variable gravity field model UCAS-IGG (University of Chinese Academy of Sciences-Institute of Geodesy and Geophysics) was solved from January 2005 to February 2010 by removing the low-frequency error of the residual orbit and residual range rate. Compared with the official institutions, the UCAS-IGG presents a good consistency in the estimating time-variable gravity field signal. This study demonstrates how the effect of the low-frequency error of the residual orbit should be taken into consideration when the longer arc length is used to recover a time-variable gravity field. Using a long arc length can reduce the variables of the initial state and recover the influence of the small force.
A Novel End-To-End Feature Selection and Diagnosis Method for Rotating Machinery
Authors: Wang Gang , Zhao Yang , Zhang Jiasi , Ning Yongjie
Published: March 2021

Feature selection is to obtain effective features from data, also known as feature engineering. Traditional feature selection and predictive model learning are separated, and there is a problem of inconsistency of criteria. This paper presents an end-to-end feature selection and diagnosis method that organically unifies feature expression learning and machine prediction learning into one model. The algorithm first combines the prediction model to calculate the mean impact value (MIVs) of the feature and realizes primary feature selection for the prediction model by selecting the feature with a larger MIV. In order to take into account the performance of the feature itself, the within-class and between-class discriminant analysis (WBDA) method is proposed, and combined with the feature diversity strategy, the feature-oriented secondary selection is realized. Eventually, feature vectors obtained by two selections are classified using a multi-class support vector machine (SVM). Compared with the modified network variable selection algorithm (MIVs), the principal component analysis dimensionality reduction algorithm (PCA), variable selection based on compensative distance evaluation technology (CDET), and other algorithms, the proposed method MIVs-WBDA exhibits excellent classification accuracy owing to the fusion of feature selection and predictive model learning. According to the results of classification accuracy testing after dimensionality reduction on rotating machinery status, the MIVs-WBDA method has a 3% classification accuracy improvement under the low-dimensional feature set. The typical running time of this classification learning algorithm is less than 10 s, while using deep learning, its running time will be more than a few hours.
Drone Secure Communication Protocol for Future Sensitive Applications in Military Zone
Authors: Ko Yongho , Kim Jiyoon , Duguma Daniel Gerbi , Astillo Philip Virgil , You Ilsun , Pau Giovanni
Published: March 2021

Unmanned Aerial Vehicle (UAV) plays a paramount role in various fields, such as military, aerospace, reconnaissance, agriculture, and many more. The development and implementation of these devices have become vital in terms of usability and reachability. Unfortunately, as they become widespread and their demand grows, they are becoming more and more vulnerable to several security attacks, including, but not limited to, jamming, information leakage, and spoofing. In order to cope with such attacks and security threats, a proper design of robust security protocols is indispensable. Although several pieces of research have been carried out with this regard, there are still research gaps, particularly concerning UAV-to-UAV secure communication, support for perfect forward secrecy, and provision of non-repudiation. Especially in a military scenario, it is essential to solve these gaps. In this paper, we studied the security prerequisites of the UAV communication protocol, specifically in the military setting. More importantly, a security protocol (with two sub-protocols), that serves in securing the communication between UAVs, and between a UAV and a Ground Control Station, is proposed. This protocol, apart from the common security requirements, achieves perfect forward secrecy and non-repudiation, which are essential to a secure military communication. The proposed protocol is formally and thoroughly verified by using the BAN-logic (Burrow-Abadi-Needham logic) and Scyther tool, followed by performance evaluation and implementation of the protocol on a real UAV. From the security and performance evaluation, it is indicated that the proposed protocol is superior compared to other related protocols while meeting confidentiality, integrity, mutual authentication, non-repudiation, perfect forward secrecy, perfect backward secrecy, response to DoS (Denial of Service) attacks, man-in-the-middle protection, and D2D (Drone-to-Drone) security.
Distributed Mode-Dependent Event-Triggered Passive Filtering for Flexible Manipulator with Semi-Markov Parameters
Authors: Ji Yidao , Zheng Suiwu
Published: March 2021

In this paper, the passive filtering problem of flexible robotic manipulator is investigated over sensor networks in a distributed manner from the control system perspective. The sensor networks are adopted to estimate true states of flexible robotic manipulator. In particular, the semi-Markov model is utilized for flexible manipulators with varying loads in unstructured environment, which is more flexible for practical implementations. Moreover, the new mode-dependent event-triggering mechanism is developed for distributed filter communications. Based on model transformation, sufficient conditions are first established to guarantee prescribed passive performance under disturbances. Then, desired mode-dependent filters are developed with the aid of convex optimization. In the end, several simulations results of a single-link flexible robotic manipulator are provided to verify the usefulness of the developed filtering algorithm.
Experimental and Numerical Investigation of the Micro-Crack Damage in Elastic Solids by Two-Way Collinear Mixing Method
Authors: Liu Hongjun , Zhao Youxuan , Zhang Han , Deng Mingxi , Hu Ning , Bi Xiaoyang
Published: March 2021

This study experimentally and numerically investigated the nonlinear behavior of the resonant bulk waves generated by the two-way collinear mixing method in 5052 aluminum alloy with micro-crack damage. When the primary longitudinal and transverse waves mixed in the micro-crack damage region, numerical and experimental results both verified the generation of resonant waves if the resonant condition ωL/ωT=2κ/(κ−1) was satisfied. Meanwhile, we found that the acoustic nonlinearity parameter (ANP) increases monotonously with increases in micro-crack density, the size of the micro-crack region, the frequency of resonant waves and friction coefficient of micro-crack surfaces. Furthermore, the micro-crack damage in a specimen generated by low-temperature fatigue experiment was employed. It was found that the micro-crack damage region can be located by scanning the specimen based on the two-way collinear mixing method.
Intensity Paradox—Low-Fit People Are Physically Most Active in Terms of Their Fitness
Authors: Vähä-Ypyä Henri , Sievänen Harri , Husu Pauliina , Tokola Kari , Vasankari Tommi
Published: March 2021

Depending on their cardiorespiratory fitness (CRF), people may perceive the exertion of incident physical activity (PA) differently. Therefore, the use of relative intensity thresholds based on individual fitness have been proposed to evaluate the accumulation of PA at different intensity levels. A subsample of the FinFit2017-study, 1952 adults (803 men and 1149 women) aged 20–69 years, participated in this study. Their maximal oxygen uptake (VO2max) was predicted with a 6 min walk test, and they were instructed to wear a triaxial hip-worn accelerometer for one week. The participants were divided into CRF tertiles by five age groups and sex. Raw acceleration data were analyzed with the mean amplitude deviation method in 6 s epochs. Additionally, the data were smoothed with 1 min and 6 min exponential moving averages. The absolute intensity threshold for moderate activity was 3.0 metabolic equivalent (MET) and for vigorous 6.0 MET. Correspondingly, the relative thresholds were 40% and 60% of the oxygen uptake reserve. Participants in the lowest CRF tertile were the most active with relative thresholds, and participants in the highest CRF tertile were the most active with absolute thresholds. High-fit people easily reached the absolute thresholds, while people in the lowest CRF tertile had to utilize most of their aerobic capacity on a daily basis simply to keep up with their daily chores or peers.
Research on the Construction of a Knowledge Graph and Knowledge Reasoning Model in the Field of Urban Traffic
Authors: Tan Jiyuan , Qiu Qianqian , Guo Weiwei , Li Tingshuai
Published: March 2021

The integration of multi-source transportation data is complex and insufficient in most of the big cities, which made it difficult for researchers to conduct in-depth data mining to improve the policy or the management. In order to solve this problem, a top-down approach is used to construct a knowledge graph of urban traffic system in this paper. First, the model layer of the knowledge graph was used to realize the reuse and sharing of knowledge. Furthermore, the model layer then was stored in the graph database Neo4j. Second, the representation learning based knowledge reasoning model was adopted to implement knowledge completion and improve the knowledge graph. Finally, the proposed method was validated with an urban traffic data set and the results showed that the model could be used to mine the implicit relationship between traffic entities and discover traffic knowledge effectively.
Security Risk Modeling in Smart Grid Critical Infrastructures in the Era of Big Data and Artificial Intelligence
Authors: Chehri Abdellah , Fofana Issouf , Yang Xiaomin
Published: March 2021

Smart grids (SG) emerged as a response to the need to modernize the electricity grid. The current security tools are almost perfect when it comes to identifying and preventing known attacks in the smart grid. Still, unfortunately, they do not quite meet the requirements of advanced cybersecurity. Adequate protection against cyber threats requires a whole set of processes and tools. Therefore, a more flexible mechanism is needed to examine data sets holistically and detect otherwise unknown threats. This is possible with big modern data analyses based on deep learning, machine learning, and artificial intelligence. Machine learning, which can rely on adaptive baseline behavior models, effectively detects new, unknown attacks. Combined known and unknown data sets based on predictive analytics and machine intelligence will decisively change the security landscape. This paper identifies the trends, problems, and challenges of cybersecurity in smart grid critical infrastructures in big data and artificial intelligence. We present an overview of the SG with its architectures and functionalities and confirm how technology has configured the modern electricity grid. A qualitative risk assessment method is presented. The most significant contributions to the reliability, safety, and efficiency of the electrical network are described. We expose levels while proposing suitable security countermeasures. Finally, the smart grid’s cybersecurity risk assessment methods for supervisory control and data acquisition are presented.
Synthesizing Multi-Layer Perceptron Network with Ant Lion Biogeography-Based Dragonfly Algorithm Evolutionary Strategy Invasive Weed and League Champion Optimization Hybrid Algorithms in Predicting Heating Load in Residential Buildings
Authors: Moayedi Hossein , Mosavi Amir
Published: March 2021

The significance of accurate heating load (HL) approximation is the primary motivation of this research to distinguish the most efficient predictive model among several neural-metaheuristic models. The proposed models are formulated through synthesizing a multi-layer perceptron network (MLP) with ant lion optimization (ALO), biogeography-based optimization (BBO), the dragonfly algorithm (DA), evolutionary strategy (ES), invasive weed optimization (IWO), and league champion optimization (LCA) hybrid algorithms. Each ensemble is optimized in terms of the operating population. Accordingly, the ALO-MLP, BBO-MLP, DA-MLP, ES-MLP, IWO-MLP, and LCA-MLP presented their best performance for population sizes of 350, 400, 200, 500, 50, and 300, respectively. The comparison was carried out by implementing a ranking system. Based on the obtained overall scores (OSs), the BBO (OS = 36) featured as the most capable optimization technique, followed by ALO (OS = 27) and ES (OS = 20). Due to the efficient performance of these algorithms, the corresponding MLPs can be promising substitutes for traditional methods used for HL analysis.
The Investigation of TiO2 NPs Effect as a Wastewater Treatment to Mitigate Cd Negative Impact on Bamboo Growth
Authors: Emamverdian Abolghassem , Ding Yulong , Mokhberdoran Farzad , Ahmad Zishan , Xie Yinfeng
Published: March 2021

The recent emerging evidence reveals that titanium dioxide nanoparticles (TiO2 NPs) can be used as a wastewater treatment. This study provides new information about the possible detoxification role of TiO2 NPs as a wastewater treatment in plants under heavy metal stress, with an emphasis on the mechanisms involved. Here, we investigated the effects of TiO2 NPs as one wastewater treatment on a bamboo species (Arundinaria pygmaea L.) under in vitro Cadmium (Cd) toxicity conditions. A factorial experiment was conducted in a completely randomized design with four replications of four concentrations of Cd (50, 100, 200, and 300 µM) alone and in combination with 100 and 200 µM TiO2 NPs as two wastewater treatments, as well as a control treatment. The results indicated that TiO2 NPs concentrations enhanced enzymatic and non-enzymatic antioxidant activities and proline accumulation as well as reducing hydrogen peroxide (H2O2), superoxide radical (O2•−), and malondialdehyde (MDA) levels, which led to improved photosynthetic parameters with an eventual increase in plant biomass as compared to the control treatment. Therefore, TiO2 NPs improved the photosynthetic parameters of bamboo under Cd toxicity, which led to an increase in plant biomass. We concluded that the wastewater treatments of TiO2 NPs improved bamboo biomass through the scavenging of reactive oxygen species (ROS) compounds (H2O2 and O2•−), which was induced by the stimulation of the antioxidant capacity of the plant. TiO2 also protected cell membranes by reducing lipoperoxidation in bamboo under Cd toxicity. The concentration of 200 µM TiO2 NPs had the most impact in reducing Cd toxicity.
Firefly Algorithm-Based Photovoltaic Array Reconfiguration for Maximum Power Extraction during Mismatch Conditions
Authors: Nazeri Mohammad Nor Rafiq , Tajuddin Mohammad Faridun Naim , Babu Thanikanti Sudhakar , Azmi Azralmukmin , Malvoni Maria , Kumar Nallapaneni Manoj
Published: March 2021

This studyaimed at improving the performance and efficiency of conventional static photovoltaic (PV) systems by introducing a metaheuristic algorithm-based approach that involves reconfiguring electrical wiring using switches under different shading profiles. Themetaheuristicalgorithmused wasthe firefly algorithm (FA), which controls the switching patterns under non-homogenous shading profiles and tracks the highest global peak of power produced by the numerous switching patterns. This study aimed to solve the current problems faced by static PV systems, such as unequal dispersion of shading affecting solar panels, multiple peaks, and hot spot phenomena, which can contribute to significant power loss and efficiency reduction. The experimental setup focusedon software development and the system or model developed in the MATLAB Simulink platform. Athorough and comprehensive analysis was done by comparing the proposed method’s overall performance and power generation with thenovel static PVseries–parallel (SP) topology and totalcross-tied (TCT) scheme. The SP configuration is widely used in the PV industry. However, the TCT configuration has superior performance and energy yield generation compared to other static PV configurations, such as the bridge-linked (BL) and honey comb (HC) configurations. The results presented in this paper provide valuable information about the proposed method’s features with regard toenhancing the overall performance and efficiency of PV arrays.
Learning Experiences of a Participatory Approach to Educating for Sustainable Development in a South African Higher Education Institution Yielding Social Learning Indicators
Authors: de Sousa Luiza Olim
Published: March 2021

A principle of sustainable development is that environmental matters are best handled with the participation of all concerned citizens. The UN has identified a gap between innovative teaching and learning methods and a participatory approach at institutions of higher education (IHE) to support interdisciplinary action. This paper shares the learning experiences of pre-service teacher students who took part in a participatory approach to educating for sustainable development in a South African IHE. A survey research design was used to collect the data from a large group (n = 376) of students over one semester. A qualitative research approach used the compulsory module’s teaching and learning tasks as intervention. Narratives were completed in groups upon completion of the module. This research established that when including a participatory approach in teaching and learning in an education for sustainable development (ESD) module at a South African IHE social learning indicators (learning, critical thinking, problem solving and dealing with conflict) emerged and students used their different perspectives when reasoning to participate collaboratively to work toward resolving environmental issues. The significance of this paper is that social learning indicators have been identified in multidisciplinary pre-service teaching and learning in a developing country when using a participatory approach in a higher education ESD module.
Performance Evaluation of Concrete Structures Using Crack Repair Methods
Authors: Kim Tae-Kyun , Park Jong-Sup
Published: March 2021

Concrete structures deteriorate over time due to cracks induced by various physical, chemical, and environmental factors. This performance degradation not only reduces their service life but may lead to human casualties and other property damage as well. While concrete crack repair can help address this problem, the implementation of the optimal repair method is important according to the environmental conditions. In this study, epoxy, impregnating, and epoxy/impregnating methods were used to repair concrete cracks. Epoxy was used for crack injection, and a supernatant was used for surface protection. The epoxy/impregnating method was used to protect both cracked areas and surfaces. Activated cracks were induced using flexural strength tests, and the stiffness of the specimens according to the repair method was compared to examine the structural performance. In addition, after the flexural strength tests, the strength, carbonation, chloride, and freeze–thaw durability were evaluated for the concrete core specimens. The impregnating method yielded the best repair performance for strength, epoxy/impregnating method for carbonation, epoxy and epoxy/impregnating methods for chloride, and epoxy/impregnating method for freezing and thawing. The results of our study enable selection of the optimal repair method to be used in practical applications based on physical, chemical, and environmental factors.
The Productivity and Nutrient Use Efficiency of Rice–Rice–Black Gram Cropping Sequence Are Influenced by Location Specific Nutrient Management
Authors: Shankar Tanmoy , Banerjee Mahua , Malik Ganesh Chandra , Dutta Sudarshan , Maiti Debtanu , Maitra Sagar , Alharby Hesham , Bamagoos Atif , Hossain Akbar , Ismail Ismail A. , EL Sabagh Ayman
Published: March 2021

Nutrient management is critical for rice farming because the crop is grown under diverse conditions, and in most cases, the existing nutrient management practices fail to achieve an attainable yield target. During recent years site specific nutrient management gained importance for a target yield with maximum nutrient use efficiency. Sufficient research work has not been carried out in this direction so far in the rice–rice–pulse (black gram) sequential cropping system under the red and lateritic belt of West Bengal, India. A multi-locational field experiment was conducted from July 2013 to June 2015 at three different locations, namely, Guskara (Burdwan district) and Benuriya (Birbhum district) villages in farmers’ fields and at the university farm of Visva-Bharati, Sriniketan, West Bengal, India. The performance of nutrients was tested by providing ample doses of N, P, K, S, and Zn compared to the omission of these nutrients. The growth parameters, such as crop biomass production, leaf area index, and number of tillers, and yield attributes and yield were influenced by nutrient management treatments. Application of 100% of N, P, K, S, and Zn resulted in its superiority to other nutrient management options studied, and a similar trend was also noted with the treatment in the expression of nutrient use efficiency (NUE) and nutrient response (NR). The available N, P, K, S, and Zn contents in soil increased steadily due to the increase in fertilizer application. The study concluded that optimization of NPK in the rice–rice–pulse cropping system on target yield along with need-based S and Zn application was beneficial for higher productivity.
Effects of High-Performance Work Systems (HPWS) on Hospitality Employees’ Outcomes through Their Organizational Commitment, Motivation, and Job Satisfaction
Authors: Dorta-Afonso Daniel , González-de-la-Rosa Manuel , García-Rodríguez Francisco , Romero-Domínguez Laura
Published: March 2021

The purpose of this research is to examine the underlying mechanisms inside the so-called black box that relate high performance work systems (HPWS) with employees’ well-being and job performance in hospitality. We surveyed a sample of 494 hotel workers to test a research model that related the following variables: HPWS, organizational commitment, motivation, job satisfaction, quality of life (QoL), and individual job performance. Structural equation modelling, namely through PLS-SEM, was conducted. We confirmed that HPWS directly influence employees’ motivation, organizational commitment, job satisfaction, and QoL. Additionally, workers’ motivation and organizational commitment positively influence job satisfaction, which, in turn, enhances workers’ QoL. Moreover, job satisfaction and quality of life significantly predicted individual job performance. This study contributes to unlocking the so-called black box relating HPWS with job outcomes as well as to the growing body of research that relates employees’ well-being with performance. From a managerial point of view, hospitality firms should prioritize investment in HPWS, as its design and implementation affects employees’ attitudes and behaviors. Future lines of research should consider bundles of practices instead of the whole HPWS effects on employees’ attitudes and behaviors.
Flowering Synchronization in Hybrid Rice Parental Lines at Different Sowing Dates
Authors: Gaballah Mahmoud , Hamad Hassan , Bamagoos Atif , Alharby Hesham , Ahmed Sharif , Ismail Ismail A. , Sohidul Islam Md , EL Sabagh Ayman
Published: March 2021

Hybrid seed set on the female line depends primarily on its flowering synchronization with the restorer line (R), therefore, the sowing of male and female lines must be planned properly to achieve this. Field experiments on different sowing dates (May 1st, May 15th, and May 30th) of R lines (Giza 178R, Giza 179R, and Giza 181R) and cytoplasmic male sterile (CMS) lines (IR69625A, IR70368A, IR58025A, K17A, and G46A) were carried out at the farm of Sakha Agricultural Research Station, Kafr El-Sheikh, Egypt during 2019 and 2020 to study the effect of sowing dates on flowering synchronization in hybrid rice. The results indicated that the synchronization of flowering between CMS lines and R lines has highly significant effects on the days to 50% heading, number of leaves, effective accumulated temperature (EAT), plant height, panicle exertion percentage, panicle length, number of fertile panicles, panicle weight, seed set percentage, harvest index and seed yield of hybrid rice. The highest seed yield (1.72 and 1.41 t ha−1, respectively in 2019 and 2020) was recorded from the sowing date May 1st and the hybrid combination of Giza 178R × IR58025A (2.06 and 2.12 t ha−1 in 2019 and 2020, respectively). The grain yield had a significant and highly significant positive correlation with the plant height (cm), panicle exertion percentage, panicle length, number of panicles plant−1, panicle weight, seed set percentage, and harvest index. In Egypt, May 1st is the best time for the synchronization of hybrid rice lines and a combination of Giza 178R × IR58025A may be recommended for better performance.
Perspective on COVID-19 Pandemic Factors Impacting Organizational Leadership
Authors: Chen James K. C. , Sriphon Thitima
Published: March 2021

Employees are important assets of an organization. Therefore, the employee engagement in teamwork is extremely vital for long-term organizational development. Good managers need excellent leadership skills. However, as the COVID-19 pandemic rapidly spreads around the world, many countries implemented strategies to avoid infection, such as working from home, isolation of infected people from others, and 14 days of self-quarantine. These strategies impact the trust, communal relationships, and social exchange relationships among organizational employees. However, communal and social exchange relationships are necessary for organizational leadership, and they are considered as the basis of social networks. The trust, communal relationships, social exchange relationships, and leadership in an organization are an interesting issue, particularly in the COVID-19 time, since the role of leaders is very crucial for maintaining organizational sustainability. The main objective of this study is to investigate the impact of COVID-19 on leadership in organizations based on trust, communal relationships, and social exchange relationships. The study employed correlation analysis to explore the interrelationships between variables. The 220 samples collected consisted of basic, middle, and high managers of organizations. The findings show that COVID-19 impacted organizational leadership. COVID-19 (F1) and (F2) factors integrated with each variable: (1) trust, (2) communal relationships, and (3) social exchange relationships created a stronger relationship between trust and leadership, communal relationships and leadership, and also social exchange relationship and leadership in organizations. On the contrary, Covid-19 (F3) factors integrated with each variable: (1) trust, (2) communal relationships, and (3) social exchange relationships decreased a relationship between trust and leadership, communal relationships and leadership, and also social exchange relationships and leadership in organizations. These results can help CEOs in organizations to perceive what factors have a positive impact or a negative impact on leadership in organizations in order to improve their leadership skills, even post COVID-19. The managerial implications are that (1) leaders need good communication skills to share true information with empathy and optimism and (2) leaders need to be thoughtful and capable to handle change in uncertain situations ethically.
Weighting the Attributes of Human-Related Activities for Fire Safety Measures in Historic Villages
Authors: Lee Ji-Hee , Chun Woo-Young , Choi Jun-Ho
Published: March 2021

Recently, numerous world heritage sites have burned down or suffered minor damage due to fires. As a result, the Korean government has developed active and passive fire measures in Korean historic villages. Nevertheless, fires have not been prevented, inciting the government to direct its attention toward community-based activities. This paper focuses on human-related fire safety measures and aims to identify the most efficient methods for preventing fires, as well as for minimizing damage caused by them in historic villages. It explores the preventive and response levels of residents and village organizations based on a survey of experts in the field and applies an analytic hierarchy process (AHP) to determine the weighting of the selected attributes. The study proposes that the preventive level is more important than the response level among village residents, and the response level should be prioritized over the preventive level in village organizations in order to prevent and reduce fire risk and damage in Korean historic villages.
The Effect of Elementary School Soccer Instruction Using Virtual Reality Technologies on Students’ Attitudes toward Physical Education and Flow in Class
Authors: Lee Hyun Suk , Lee Junga
Published: March 2021

We analyzed the effects of an elementary school soccer class using virtual reality technology on students’ attitudes toward physical education class and the influence on class flow. The data from 113 elementary school students from Seoul and Gyeonggi-do were analyzed. Students were divided into groups that received either virtual reality or traditional classes (e.g., playing on a playground). Data were analyzed with three-way analyses of variance. Results revealed that students who participated in the virtual reality classes had more confidence, concentration, and experienced more flow (specifically, attention to PE class, integration of ability, challenge, and sense of control) than students who participated in the traditional class. This suggests that virtual reality technology positively affected students’ attitudes and flow. In subsequent research, it is necessary to develop and disseminate a variety of virtual reality sports programs and to conduct studies with students from various grade levels.
The COVID-19 Lockdown Effect on the Intention to Purchase Sustainable Brands
Authors: Alexa Lidia , Apetrei Andreea , Sapena Juan
Published: March 2021

After the World Health Organization (WHO) declared the COVID-19 pandemic on 11 March 2020, almost all European countries entered a lockdown. This context caused sudden changes at multiple levels, affecting the way people were working, buying, studying and even the way they were interacting. Moreover, during lockdown people showed a special attention to local and sustainable brands giving momentum to the interest on sustainability, that has been increasing in the last years. Therefore, this study aims to determine the intention of buying sustainable and local brands due to the COVID-19 lockdown. An online survey was conducted for two groups of young adults from Spain and Romania, between April and June 2020. The questionnaire respects the methodological recommendations of Azjen (1985) and related literature on how to construct a survey based on the theory of planned behavior (TPB) and it aims to gather information about the three main constructs that determine the individual’s behavioral intention: attitudes, subjective norms and perceived behavioral control. The results suggest that both Spanish and Romanian samples intended to buy more local and sustainable brands, despite the slightly different attitudes. Moreover, the data show that both subjective norms and perceived behavioral control influence attitudes toward sustainable and local brands, and hence, indirectly the intention to buy sustainable products. The outcomes are adding to the literature on sustainability, and understanding the effects of COVID-19 on consumer behavior. Additionally, the results can help better understand the importance of sustainability in Spain and Romania, and therefore, offering support to practitioners in building policies and programs that encourage a sustainable lifestyle.
Tensor-Based Adaptive Filtering Algorithms
Authors: Dogariu Laura-Maria , Stanciu Cristian-Lucian , Elisei-Iliescu Camelia , Paleologu Constantin , Benesty Jacob , Ciochină Silviu
Published: March 2021

Tensor-based signal processing methods are usually employed when dealing with multidimensional data and/or systems with a large parameter space. In this paper, we present a family of tensor-based adaptive filtering algorithms, which are suitable for high-dimension system identification problems. The basic idea is to exploit a decomposition-based approach, such that the global impulse response of the system can be estimated using a combination of shorter adaptive filters. The algorithms are mainly tailored for multiple-input/single-output system identification problems, where the input data and the channels can be grouped in the form of rank-1 tensors. Nevertheless, the approach could be further extended for single-input/single-output system identification scenarios, where the impulse responses (of more general forms) can be modeled as higher-rank tensors. As compared to the conventional adaptive filters, which involve a single (usually long) filter for the estimation of the global impulse response, the tensor-based algorithms achieve faster convergence rate and tracking, while also providing better accuracy of the solution. Simulation results support the theoretical findings and indicate the advantages of the tensor-based algorithms over the conventional ones, in terms of the main performance criteria.
Ladders of Authority, Status, Responsibility and Ideology: Toward a Typology of Hierarchy in Social Systems
Authors: Romme A. Georges L.
Published: March 2021

Hierarchy is a key characteristic of any complex system. This paper explores which notions of hierarchy are being used in the field of organization and management studies. Four distinct types of hierarchy are identified: a ladder of formal decision-making authority, a ladder of achieved status, a self-organized ladder of responsibility and an ideology-based ladder. A social mechanism-based perspective serves to define and distinguish these four types. Subsequently, the typology is further developed by comparing the four hierarchy types in terms of their tacit/explicitness, (in)transitivity and behavior- versus cognition-centeredness. This article contributes to the literature by dissecting the general metaphor of hierarchy into four different constructs and their social mechanisms, which serves to create a typology of the various ways in which complex social systems can be characterized as hierarchical. This typology can inform future research drawing on any type of hierarchy.
Vulnerability and Burden of All-Cause Mortality Associated with Particulate Air Pollution during COVID-19 Pandemic: A Nationwide Observed Study in Italy
Authors: Ye Tingting , Xu Rongbin , Yu Wenhua , Chen Zhaoyue , Guo Yuming , Li Shanshan
Published: March 2021

Background: Limited evidence is available on the health effects of particulate matter (PM including PM2.5 with an aerodynamic diameter ≤ 2.5 μm; PM10, ≤ 10 μm; PM2.5–10, 2.5–10 μm) during the pandemic of COVID-19 in Italy. The aims of the study were to examine the associations between all-cause mortality and PM in the pandemic period and compare them to the normal periods (2015–2019). Methods: We collected daily data regarding all-cause mortality (stratified by age and gender), and PM concentrations for 107 Italian provinces from 1 January 2015 to 31 May 2020. A time-stratified case-cross design with the distributed lag non-linear model was used to examine the association between PM and all-cause mortality. We also compared the counts and fractions of death attributable to PM in two periods. Results: Italy saw an increase in daily death counts while slight decreases in PM concentrations in pandemic period. Each 10 µg/m3 increase in PM was associated with much higher increase in daily all-cause mortality during the pandemic period compared to the same months during 2015–2019 (increased mortality rate: 7.24% (95%CI: 4.84%, 9.70%) versus 1.69% (95%CI: 1.12%, 2.25%) for PM2.5; 3.45% (95%CI: 2.58%, 4.34%) versus 1.11% (95%CI: 0.79%, 1.42%) for PM10; 4.25% (95%CI: 2.99%, 5.52%) versus 1.76% (95%CI: 1.14%, 2.38%) for PM2.5–10). The counts and fractions of deaths attributable to PM were higher in 2020 for PM2.5 (attributable death counts: 20,062 versus 3927 per year in 2015–2019; attributable fractions: 10.2% versus 2.4%), PM10 (15,112 versus 3999; 7.7% versus 2.5%), and PM2.5–10 (7193 versus 2303; 3.7% versus 1.4%). Conclusion: COVID-19 pandemic increased the vulnerability and excess cases of all-cause mortality associated with short-term exposure to PM2.5, PM2.5–10, and PM10 in Italy, despite a decline in air pollution level.
Design, Synthesis and Characterization of HIV-1 CA-Targeting Small Molecules: Conformational Restriction of PF74
Authors: Sahani Rajkumar Lalji , Diana-Rivero Raquel , Vernekar Sanjeev Kumar V. , Wang Lei , Du Haijuan , Zhang Huanchun , Castaner Andres Emanuelli , Casey Mary C. , Kirby Karen A. , Tedbury Philip R. , Xie Jiashu , Sarafianos Stefan G. , Wang Zhengqiang
Published: March 2021

Small molecules targeting the PF74 binding site of the HIV-1 capsid protein (CA) confer potent and mechanistically unique antiviral activities. Structural modifications of PF74 could further the understanding of ligand binding modes, diversify ligand chemical classes, and allow identification of new variants with balanced antiviral activity and metabolic stability. In the current work, we designed and synthesized three series of PF74-like analogs featuring conformational constraints at the aniline terminus or the phenylalanine carboxamide moiety, and characterized them using a biophysical thermal shift assay (TSA), cell-based antiviral and cytotoxicity assays, and in vitro metabolic stability assays in human and mouse liver microsomes. These studies showed that the two series with the phenylalanine carboxamide moiety replaced by a pyridine or imidazole ring can provide viable hits. Subsequent SAR identified an improved analog 15 which effectively inhibited HIV-1 (EC50 = 0.31 μM), strongly stabilized CA hexamer (ΔTm = 8.7 °C), and exhibited substantially enhanced metabolic stability (t1/2 = 27 min for 15 vs. 0.7 min for PF74). Metabolic profiles from the microsomal stability assay also indicate that blocking the C5 position of the indole ring could lead to increased resistance to oxidative metabolism.
Human Protoparvovirus DNA and IgG in Children and Adults with and without Respiratory or Gastrointestinal Infections
Authors: Mohanraj Ushanandini , Jokinen Maija , Thapa Rajita Rayamajhi , Paloniemi Minna , Vesikari Timo , Lappalainen Maija , Tarkka Eveliina , Nora-Krūkle Zaiga , Vilmane Anda , Vettenranta Kim , Mangani Charles , Oikarinen Sami , Fan Yue-Mei , Ashorn Per , Väisänen Elina , Söderlund-Venermo Maria
Published: March 2021

Three human protoparvoviruses, bufavirus (BuV), tusavirus (TuV) and cutavirus (CuV), have recently been discovered in diarrheal stool. BuV has been associated with diarrhea and CuV with cutaneous T-cell lymphoma, but there are hardly any data for TuV or CuV in stool or respiratory samples. Hence, using qPCR and IgG enzyme immunoassays, we analyzed 1072 stool, 316 respiratory and 445 serum or plasma samples from 1098 patients with and without gastroenteritis (GE) or respiratory-tract infections (RTI) from Finland, Latvia and Malawi. The overall CuV-DNA prevalences in stool samples ranged between 0–6.1% among our six patient cohorts. In Finland, CuV DNA was significantly more prevalent in GE patients above rather than below 60 years of age (5.1% vs 0.2%). CuV DNA was more prevalent in stools among Latvian and Malawian children compared with Finnish children. In 10/11 CuV DNA-positive adults and 4/6 CuV DNA-positive children with GE, no known causal pathogens were detected. Interestingly, for the first time, CuV DNA was observed in two nasopharyngeal aspirates from children with RTI and the rare TuV in diarrheal stools of two adults. Our results provide new insights on the occurrence of human protoparvoviruses in GE and RTI in different countries.
Construction and Immunological Evaluation of an Adenoviral Vector-Based Vaccine Candidate for Lassa Fever
Authors: Wang Meirong , Li Ruihua , Li Yaohui , Yu Changming , Chi Xiangyang , Wu Shipo , Liu Shulin , Xu Junjie , Chen Wei
Published: March 2021

Lassa virus (LASV) is a rodent-borne arenavirus circulating in West African regions that causes Lassa fever (LF). LF is normally asymptomatic at the initial infection stage, but can progress to severe disease with multiorgan collapse and hemorrhagic fever. To date, the therapeutic choices are limited, and there is no approved vaccine for avoiding LASV infection. Adenoviral vector-based vaccines represent an effective countermeasure against LASV because of their safety and adequate immunogenicity, as demonstrated in use against other emerging viral infections. Here, we constructed and characterized a novel Ad5 (E1-, E3-) vectored vaccine containing the glycoprotein precursor (GPC) of LASV. Ad5-GPCLASV elicited both humoral and cellular immune responses in BALB/c mice. Moreover, a bioluminescent imaging-based BALB/c mouse model infected with GPC-bearing and luciferase-expressing replication-incompetent LASV pseudovirus was utilized to evaluate the vaccine efficacy. The bioluminescence intensity of immunized mice was significantly lower than that of control mice after being inoculated with LASV pseudovirus. This study suggests that Ad5-GPCLASV represents a potential vaccine candidate against LF.
Antibody Response to a Live-Modified Virus Vaccine against Bovine Viral Diarrhoea in Dairy Cattle in a Field Trial
Authors: Klimowicz-Bodys Małgorzata D. , Płoneczka-Janeczko Katarzyna , Czopowicz Michał , Polak Mirosław Paweł , Lachowicz-Wolak Agnieszka , Rypuła Krzysztof
Published: March 2021

(1) Background: The objective of the study was to evaluate the long-term antibody response of dairy cows to a single dose of a commercial modified-live virus (MLV) vaccine against bovine viral diarrhea (Mucosiffa® CEVA Sante Animale, Liburne, France). (2) Methods: The study was carried out in a dairy cattle herd counting 290 animals negative for bovine viral diarrhoea virus (BVDV). The vaccination was implemented following the manufacturer’s instructions. Twelve dairy cows were randomly selected before the study, and blood samples were collected right before the vaccination and then 12 times at 1-month intervals. The serum samples were screened using a virus neutralization test (VNT) and ELISA. (3) Results: Both tests showed that antibody titers increased significantly in all animals within the first month post-vaccination, and continued to increase significantly until the second (VNT) and third (ELISA) month post-vaccination. Antibody titers remained high and stable until the end of the study. Moreover, cows did not show any adverse reactions or clinical symptoms of the disease. (4) Conclusion: The results of this study indicated that the administration of one dose MLV vaccine was able to stimulate long-lasting (12-months) and strong antibody response in all vaccinated cows.
Water Footprint and Life Cycle Assessment: The Complementary Strengths of Analyzing Global Freshwater Appropriation and Resulting Local Impacts
Authors: Gerbens-Leenes Winnie , Berger Markus , Allan John
Published: March 2021

Considering that 4 billion people are living in water-stressed regions and that global water consumption is predicted to increase continuously [...]
Towards an Enhanced Institutional Structure of the Eurasian Economic Union
Authors:   Institute for Competitiveness and Integration, Pilipenko Igor V.
Published: March 2021

This article considers how to enhance the institutional structure of the Eurasian Economic Union (EAEU) in order to enable timely decision-making and implementation of governance decisions in the interests of Eurasian integration deepening. We compare the governance structures of the EAEU and the European Union (EU) using the author’s technique and through the lens of theories of neofunctionalism and intergovernmentalism elaborated with respect to the EU. We propose to determine a major driver of the integration process at this stage (the College of the Eurasian Economic Commission or the EAEU member states), to reduce the number of decision-making bodies within the current institutional structure of the EAEU, and to divide clearly authority and competence of remaining bodies to exclude legal controversies in the EAEU.
Theories of Society and Risks of Its Development
Authors:   Lomonosov Moscow State University, Morozov Vladimir A.
Published: March 2021

The article deals with various types of characteristics of society and its sphere of activity. Various types and groups of theories of society development are studied. It is revealed — what values are laid by scientific schools in the life of society. Global problems and contradictions, which are a brake and at the same time a stimulus for its development, are defined. The planetary scheme of interrelations and mutual influence of global risks for society is developed. The gradation of modern problems of society from risks with the indication of the main problems of social and economic character is carried out. The separate directions of development of society and tools which reduce emergence and development of risks for it are considered.
European Company and European Cooperative Society as Forms of Supranational Business Organization in the European Union
Authors:   Lomonosov Moscow State University, Sokolov Aleksei O.
Published: March 2021

The present article analyzes the experience of creation and functioning in the European Union of such supranational forms of business organization as European companies (SE) and European cooperative societies (SCE). The author considers the main stages of developing legislative acts regulating the activities of supranational business structures; requirements for such companies; procedure for their establishment; opportunities provided by supranational status. The data on activities of European companies and cooperative societies is summarized. Possibilities of implementing the experience of European companies in the EAEU are analyzed.