bluuebunny/crossref_metadata_2025 huggingface dataset:
Validity of Hololens Augmented Reality Head Mounted Display for Measuring Gait Parameters in Healthy Adults and Children with Cerebral Palsy
Authors: Guinet Anne-Laure , Bouyer Guillaume , Otmane Samir , Desailly Eric
Published: April 2021

Serious games are a promising approach to improve gait rehabilitation for people with gait disorders. Combined with wearable augmented reality headset, serious games for gait rehabilitation in a clinical setting can be envisaged, allowing to evolve in a real environment and provide fun and feedback to enhance patient’s motivation. This requires a method to obtain accurate information on the spatiotemporal gait parameters of the playing patient. To this end, we propose a new algorithm called HoloStep that computes spatiotemporal gait parameters using only the head pose provided by an augmented reality headset (Hololens). It is based on the detection of peaks associated to initial contact event, and uses a combination of locking distance, locking time, peak amplitude detection with custom thresholds for children with CP. The performance of HoloStep was compared during a walking session at comfortable speed to Zeni’s reference algorithm, which is based on kinematics and a full 3D motion capture system. Our study included 62 children with cerebral palsy (CP), classified according to Gross Motor Function Classification System (GMFCS) between levels I and III, and 13 healthy participants (HP). Metrics such as sensitivity, specificity, accuracy and precision for step detection with HoloStep were above 96%. The Intra-Class Coefficient between steps length calculated with HoloStep and the reference was 0.92 (GMFCS I), 0.86 (GMFCS II/III) and 0.78 (HP). HoloStep demonstrated good performance when applied to a wide range of gait patterns, including children with CP using walking aids. Findings provide important insights for future gait intervention using augmented reality games for children with CP.
Full-Color See-Through Three-Dimensional Display Method Based on Volume Holography
Authors: Wu Taihui , Ma Jianshe , Wang Chengchen , Wang Haibei , Su Ping
Published: April 2021

We propose a full-color see-through three-dimensional (3D) display method based on volume holography. This method is based on real object interference, avoiding the device limitation of spatial light modulator (SLM). The volume holography has a slim and compact structure, which realizes 3D display through one single layer of photopolymer. We analyzed the recording mechanism of volume holographic gratings, diffraction characteristics, and influencing factors of refractive index modulation through Kogelnik’s coupled-wave theory and the monomer diffusion model of photopolymer. We built a multiplexing full-color reflective volume holographic recording optical system and conducted simultaneous exposure experiment. Under the illumination of white light, full-color 3D image can be reconstructed. Experimental results show that the average diffraction efficiency is about 53%, and the grating fringe pitch is less than 0.3 μm. The reconstructed image of volume holography has high diffraction efficiency, high resolution, strong stereo perception, and large observing angle, which provides a technical reference for augmented reality.
Optical Voltage Transformer Based on FBG-PZT for Power Quality Measurement
Authors: Gonçalves Marceli N. , Werneck Marcelo M.
Published: April 2021

Optical Current Transformers (OCTs) and Optical Voltage Transformers (OVTs) are an alternative to the conventional transformers for protection and metering purposes with a much smaller footprint and weight. Their advantages were widely discussed in scientific and technical literature and commercial applications based on the well-known Faraday and Pockels effect. However, the literature is still scarce in studies evaluating the use of optical transformers for power quality purposes, an important issue of power system designed to analyze the various phenomena that cause power quality disturbances. In this paper, we constructed a temperature-independent prototype of an optical voltage transformer based on fiber Bragg grating (FBG) and piezoelectric ceramics (PZT), adequate to be used in field surveys at 13.8 kV distribution lines. The OVT was tested under several disturbances defined in IEEE standards that can occur in the electrical power system, especially short-duration voltage variations such as SAG, SWELL, and INTERRUPTION. The results demonstrated that the proposed OVT presents a dynamic response capable of satisfactorily measuring such disturbances and that it can be used as a power quality monitor for a 13.8 kV distribution system. Test on the proposed system concluded that it was capable to reproduce up to the 41st harmonic without significative distortion and impulsive surges up to 2.5 kHz. As an advantage, when compared with conventional systems to monitor power quality, the prototype can be remote-monitored, and therefore, be installed at strategic locations on distribution lines to be monitored kilometers away, without the need to be electrically powered.
Blindness and the Reliability of Downwards Sensors to Avoid Obstacles: A Study with the EyeCane
Authors: Bleau Maxime , Paré Samuel , Djerourou Ismaël , Chebat Daniel R. , Kupers Ron , Ptito Maurice
Published: April 2021

Vision loss has dramatic repercussions on the quality of life of affected people, particularly with respect to their orientation and mobility. Many devices are available to help blind people to navigate in their environment. The EyeCane is a recently developed electronic travel aid (ETA) that is inexpensive and easy to use, allowing for the detection of obstacles lying ahead within a 2 m range. The goal of this study was to investigate the potential of the EyeCane as a primary aid for spatial navigation. Three groups of participants were recruited: early blind, late blind, and sighted. They were first trained with the EyeCane and then tested in a life-size obstacle course with four obstacles types: cube, door, post, and step. Subjects were requested to cross the corridor while detecting, identifying, and avoiding the obstacles. Each participant had to perform 12 runs with 12 different obstacles configurations. All participants were able to learn quickly to use the EyeCane and successfully complete all trials. Amongst the various obstacles, the step appeared to prove the hardest to detect and resulted in more collisions. Although the EyeCane was effective for detecting obstacles lying ahead, its downward sensor did not reliably detect those on the ground, rendering downward obstacles more hazardous for navigation.
Two-Stage Water Jet Landing Point Prediction Model for Intelligent Water Shooting Robot
Authors: Lin Yunhan , Ji Wenlong , He Haowei , Chen Yaojie
Published: April 2021

In this paper, an intelligent water shooting robot system for situations of carrier shake and target movement is designed, which uses a 2 DOF (degree of freedom) robot as an actuator, a photoelectric camera to detect and track the desired target, and a gyroscope to keep the robot’s body stable when it is mounted on the motion carriers. Particularly, for the accurate shooting of the designed system, an online tuning model of the water jet landing point based on the back-propagation algorithm was proposed. The model has two stages. In the first stage, the polyfit function of Matlab is used to fit a model that satisfies the law of jet motion in ideal conditions without interference. In the second stage, the model uses the back-propagation algorithm to update the parameters online according to the visual feedback of the landing point position. The model established by this method can dynamically eliminate the interference of external factors and realize precise on-target shooting. The simulation results show that the model can dynamically adjust the parameters according to the state relationship between the landing point and the desired target, which keeps the predicted pitch angle error within 0.1°. In the test on the actual platform, when the landing point is 0.5 m away from the position of the desired target, the model only needs 0.3 s to adjust the water jet to hit the target. Compared to the state-of-the-art method, GA-BP (genetic algorithm-back-propagation), the proposed method’s predicted pitch angle error is within 0.1 degree with 1/4 model parameters, while costing 1/7 forward propagation time and 1/200 back-propagation calculation time.
Towards Dependable IoT via Interface Selection: Predicting Packet Delivery at the End Node in LoRaWAN Networks
Authors: Guerrero Marc , Cano Cristina , Vilajosana Xavier , Thubert Pascal
Published: April 2021

Estimating channel conditions to predict packet delivery can be exploited as a powerful tool to ensure wireless networks dependability. In this article we explore the practical application of this idea from the end-device perspective, using the LoRaWAN protocol stack. We aim to understand if packet delivery can be estimated considering different levels of feedback at the end-device. For that, an extensive data collection campaign is carried out. Through an analysis of the obtained traces, we establish correlations between connectivity metrics at the end node and the fact that a packet is received at the gateway. The study is complemented considering different levels of feedback: (i) No feedback, (ii) enabling acknowledgements frames, and (iii) considering application/control plane data about the channel status at the gateway side. The results show that it is possible to estimate packet delivery in all the evaluated cases.
Unaccompanied Minors in Greece and Italy: An Exploration of the Challenges for Social Work within Tighter Immigration and Resource Constraints in Pandemic Times
Authors: Barn Ravinder , Di Rosa Roberta Teresa , Kallinikaki Theano
Published: April 2021

The number of unaccompanied minors (UAMs) arriving in the European Union (EU) has been increasing dramatically over recent years resulting in the formulation of EU policy directives around safeguarding and well-being. Notably, the majority of UAMs enter Europe irregularly through two main gateways to the European continent: via Italy, using the Central Mediterranean Sea route; or through Greece, transiting through the Eastern Mediterranean route from Turkey, mostly via sea. Profiles of UAMs travelling via the two different routes are significantly diverse, reflecting Italy’s and Greece’s geographical proximity to North Africa and the Middle East, respectively. Although Italy has witnessed a decline since 2018 (Todaro and Romano 2019), the two countries have faced a significant increase in UAMs, and this has required a considerable reorganisation of the reception systems and, more generally, of their welfare systems. However, difficulties in securing adequate reception for UAMs seeking protection have persisted in both countries. Through an analysis of the impact of the pandemic on the Italian and Greek reception systems and social interventions with UAMs, we utilised a multiple embedded case study approach within a comparative analysis, to identify key changes in the main services which should be guaranteed to minors—namely, hosting/housing, guardianship, foster care, family/relatives reunification, school integration, language, job training for care leaving, and preparation for leaving care after 18 years (Di Rosa 2017; Buchanan and Kallinikaki 2018; Barn et al. 2020). Against a background of critical reviews of the main issues related to policies and reported social work practice in a context of COVID-19 precarity, set within a wider EU framework, this paper contributes to the literature with an analysis of the current situation and the tightening of the conditions of reception, inclusion and integration that await UAMs in these gateway countries today. We conclude that with the suspension of key services and amenities, and with a practical halt to the due process of immigration and asylum, social workers are facing a difficult challenge to prevent the deterioration of UAMs’ mental health and well-being.
Does Paying for Aquatic Resources Matter? A Case of an African Riverine Ecosystem
Authors: Chigamba Gladys , Limuwa Moses , Kaunda Emmanuel
Published: April 2021

Valuation of environmental goods and services has an important role to play in the protection and conservation of riverine resources. However, the literature shows a dearth of information regarding factors that influence people’s willingness to pay (WTP) for riverine resources. This research study was undertaken to find out key factors that affect the willingness of people to pay for the conservation of aquatic resources in the lower section of the Linthipe River in Malawi. Data was collected through household interviews, focus group discussions, key informant interviews, and contingent valuation (CV) surveys. The study noted that communities were willing to offer $3.51 per year for the conservation of aquatic resources in the river. This study established that the people’s WTP is a function of education level, household usage of the goods and services, community support in the management of the resources, household income, and distance of the household from the river ecosystem. The study further discovered that the pay-out level of the users along the Linthipe River was driven by household usage of resources from the river, period of stay in the area, and level of household income. Our recommendation is that government and development partners should popularize the important role played by rivers and streams to surrounding communities and beyond to appeal for more support from users. The authorities must further empower the communities along the rivers and streams to sustainably manage the aquatic resources for the continued appreciation of aquatic resources by future generations.
Industry Leaders’ Perceptions of Residential Wood Pellet Technology Diffusion in the Northeastern U.S.
Authors: Olechnowicz Casey , Leahy Jessica , Guo Tian , Silver Huff Emily , Danks Cecilia , Adams Maura
Published: April 2021

Within a shifting climate of renewable energy options, technology innovations in the energy sector are vital in combating fossil-fuel-driven climate change and economic growth. To enter this market dominated by fossil fuels, renewable energy innovations need to overcome significant barriers related to cost, relative advantages compared to fossil fuels, and policy incentive programs. A better understanding of the innovation diffusion of new technologies in establishing the renewable energy industry can aid policy makers in designing and implementing other renewable energy support programs and improving adoption rates within existing programs. This study assessed industry leaders’ perceptions through semi-structured interviews. We explored the innovation diffusion process of wood pellet residential heating technology, as well as policy needs and barriers within this industry that are hindering successful long-term diffusion and sustainability. We show that while there is high potential to the wood pellet industry in terms of local resources and overall advantages to fossil fuels, it can be difficult to achieve sustainable economic growth with current cost barriers and further policy programs and incentives are needed in addition to improved communication to reduce adoption barriers for wood pellet technology.
Fly Ash from Thermal Conversion of Sludge as a Cement Substitute in Concrete Manufacturing
Authors: Rutkowska Gabriela , Chalecki Marek , Żółtowski Mariusz
Published: April 2021

Striving for reduction of production costs and constraints on natural resources cause the use of waste materials as substitutes of traditional raw materials to become increasingly important. Dynamic development of sewerage systems and sewage treatment plants observed over the recent years leads to increase of mass of the produced sewage sludge. According to the Waste Law, the municipal sewage sludge can be used if it is properly stabilized, e.g., through thermal processing. This process results in significant quantities of fly ash which must be properly utilized. The paper presents results of investigations of influence of partial replacement of cement by the fly ash from sewage sludge on concrete parameters. It was designed as a C20/25 class concrete mix, based on the Portland cement CEM I 42.5R with various ash content. Physical and chemical properties of the ash as well as frost resistance and the compressive strength of the concrete after 28, 56 and 365 days of curing were investigated. The obtained results of investigations confirm the possibility of application of fly ash wastes as a cement substitute in the concrete manufacturing. If a predefined quantity of cement is replaced by the fly ash, then one can obtain cement composite with good strength parameters.
Using Composition to Assess and Enhance Visual Values in Landscapes
Authors: Gyurkovich Magdalena , Pieczara Marta
Published: April 2021

(1) The research presented in this paper aims to study the value attributed to a landscape composition’s visual elements and their overall influence on how they are perceived. The historical and contemporary visual approaches to a landscape constitute its background, for example, geographical, aesthetic, iconographic, phenomenological. (2) The visual assessment method elaborated by the Polish school of landscape architecture is used in the first part of this study. It is built of three steps with corresponding tools: landscape inventory, composition analysis, and evaluation. Moreover, an expert survey is used to complete the study. The work’s novelty is completing the visual approach with an expert inquiry, which aims to solve the subjectivity issue, an inherent visual evaluation controversy. The study area comprises urban and suburban locations from the agglomeration of Poznań, Poland. (3) The research results indicate the significant contribution of three visual elements to the positive assessment of landscape values: greenery, built heritage, and water. The importance of the composition is also demonstrated. (4) The main research findings show that visual evaluation tools should be implemented as part of sustainable spatial planning. Their implementation permits identifying the essential positive value in the existing landscape and creating guidelines for its preservation or enhancement. The article’s significance is the effect of proposing real and possible guidelines to improve the spatial planning policy, making landscape management more sustainable.
Evaluation and Influencing Factors of Industrial Pollution in Jilin Restricted Development Zone: A Spatial Econometric Analysis
Authors: Guo Yanhua , Tong Lianjun , Mei Lin
Published: April 2021

Winning the battle against pollution and strengthening ecological protection in all respects are vital for promoting green development and building a moderately prosperous ecological civilization in China. Using the entropy weight method, this paper establishes and evaluates a comprehensive industrial pollution index that contains and synthesizes six major industrial pollutants (wastewater, COD, waste gas, SO2, NOx, and solid waste) in the 2006–2015 period. Subsequently, this paper studies the spatiotemporal characteristics and influencing factors of industrial pollution via the Moran index and spatial econometric analysis. The empirical results indicate that (1) the temporal evolution of the industrial pollution index is characterized by an overall trend of first decreasing and then increasing. (2) The industrial pollution index of each county has certain geographical disparities and significant spatially polarized characteristics in 2006, 2009, 2012, and 2015. (3) The Moran test shows that there is a relatively significant spatial autocorrelation of the industrial pollution index among counties and that the geographical distribution of the industrial pollution index tends to show clustering. (4) Spatial regression models that incorporate spatial factors better explain the influencing factors of industrial pollution. The economic development level, technological progress, and industrialization are negatively correlated with industrial pollution, while population density and industrial production capacity are positively correlated. (5) Consequently, as relevant policy recommendations, this paper proposes that environmental cooperation linkage mechanisms, environmental protection credit systems, and green technology innovation systems should be established in different geographical locations to achieve the goals of green county construction and sustainable development.
Place-Sensing through Haptic Interfaces: Proposing an Alternative to Modern Sustainability Education
Authors: Swillens Viktor , Decuypere Mathias , Vandenabeele Joke , Vlieghe Joris
Published: April 2021

In this article we address the issue of how an instrumental approach to sustainability education has dominated the scientific debate of the last 20 years. By conducting interviews and focus group interviews, we have investigated a community arts initiative in the Flemish city of Antwerp in which artists together with local inhabitants engaged in activities around two art installations and address the sustainability of a particular living environment. Our empirical study of this place-based initiative that we call a ‘critical zone observatory’ has been enriched by the work of Bruno Latour, Richard Sennett and Hans Schildermans. We conclude that a temporal and spatial shift in sustainability education (research) is needed from (1) development (a steady movement towards a planned future) and (2) human stewardship (the capability of people to shape their passive living environments) to (1) what we call co-sperity (a collective hope in the present) and (2) inhabitation (an attached and undetermined engagement with the dynamic of one’s habitat). By proposing a collective study pedagogy as an alternative to individual training, we suggest a need for future research on critical zone observatories.
Distributed Ledger Technology Applications in Food Supply Chains: A Review of Challenges and Future Research Directions
Authors: Nurgazina Jamilya , Pakdeetrakulwong Udsanee , Moser Thomas , Reiner Gerald
Published: April 2021

The lack of transparency and traceability in food supply chains (FSCs) is raising concerns among consumers and stakeholders about food information credibility, food quality, and safety. Insufficient records, a lack of digitalization and standardization of processes, and information exchange are some of the most critical challenges, which can be tackled with disruptive technologies, such as the Internet of Things (IoT), blockchain, and distributed ledger technologies (DLTs). Studies provide evidence that novel technological and sustainable practices in FSCs are necessary. This paper aims to describe current practical applications of DLTs and IoT in FSCs, investigating the challenges of implementation, and potentials for future research directions, thus contributing to achievement of the United Nations’ Sustainable Development Goals (SDGs). Within a systematic literature review, the content of 69 academic publications was analyzed, describing aspects of implementation and measures to address the challenges of scalability, security, and privacy of DLT, and IoT solutions. The challenges of high costs, standardization, regulation, interoperability, and energy consumption of DLT solutions were also classified as highly relevant, but were not widely addressed in literature. The application of DLTs in FSCs can potentially contribute to 6 strategic SDGs, providing synergies and possibilities for more sustainable, traceable, and transparent FSCs.
Sustainability of Organizations: The Contribution of Personal Values to Democratic Leadership Behavior Focused on the Sustainability of Organizations
Authors: Nedelko Zlatko , Potocan Vojko
Published: April 2021

The main purpose of this study was to examine the influence of leaders’ personal values on their democratic behavior from a sustainability perspective. We specified and tested the research model, drawing upon modified versions of the theory of basic values and the autocratic–democratic leadership continuum. A total of 208 Slovenian and 196 Austrian leaders’ responses were used in hierarchical regression and structural equation modeling analysis. The results reveal a significant and positive influence of collectivistic values in both samples on democratic leadership behavior. A significant and negative effect of individualistic values on democratic leadership behavior is present in Austria, while in Slovenia, the effect is positive but not significant. Based on acknowledged associations between leader’s values, leaders’ democratic leadership behavior, and sustainable development, we argue that democratic leadership behavior contributes to the sustainable working and behavior of organizations. These results have theoretical implications, indicating how personal values affect leaders’ democratic behavior and contribute to the sustainable working and behavior of organizations. The practical implications relate to the strengthening of leaders’ democratic behavior in Slovenian and Austrian organizations. In addition, these findings will be helpful in increasing the sustainability of organizations via fostering democratic leadership behavior and its underlying personal values.
Sustainable Sports Tourism Performance Assessment Using Grey-Based Hybrid Model
Authors: Yang Chin-Cheng , Shen Chih-Chien , Lin Yu-Sheng , Lo Huai-Wei , Wu Jia-Zhi
Published: April 2021

The development of sports tourism is gaining momentum around the world, with many tourism industries combining sports events and programs to attract more domestic and overseas customers to promote economic and culture. Sustainability awareness has been gaining attention from many international organizations, resulting in the rise of sports tourism that incorporates sustainability. Therefore, the development of a valid and applicable sustainable sports tourism (SST) assessment model is an important task. In this study, a hybrid Multiple Attribute Decision-Making (MADM) model is proposed to measure the development performance of SST. The aims of this study include developing a SST assessment framework, identifying the mutual influential relationships among attributes, generating attribute influence weights, and calculating the performance of the evaluated items. The proposed model is divided into three stages. First, a cause-and-effect diagram is generated using the Grey Decision-Making Trial and Evaluation Laboratory (GDEMATEL) to describe the interactions and feedback among the attributes. Then, the GDEMATEL-based Analytic Network Process (GDANP) is applied to generate the influence weights of the attributes and their rankings. Finally, the expanded Probability-based Grey Relational Analysis (expanded PGRA) was applied to calculate the performance of the evaluated items and to determine the gap between evaluated items and the aspiration level. This study improves the original PGRA technique by introducing the concept of aspiration level into the PGRA calculation process, thereby replacing the traditional concept of “relative satisfaction” with “aspiration level”. In addition, the expanded PGRA can assess a single rated item without being limited to at least two items. We used the Sun Moon Lake Scenic Area in Taiwan as a model demonstration. The results show that the top three attributes that need to be strengthened are disease prevention and treatment, local social welfare and protection, and sports diversity. In the Sun Moon Lake, intersection control should be set up to ensure the health status of visitors and local residents. In addition to epidemic prevention, more measures and behaviors should be developed to deal with tourism diseases. We suggested that subsidies be provided to local residents to rebuild the fences around their homes to avoid disturbances caused by the influx of tourists. Moreover, the local government can create more sports events with special characteristics that can attract tourists to come again and again.
Integrating Regionalized Socioeconomic Considerations onto Life Cycle Assessment for Evaluating Bioeconomy Value Chains: A Case Study on Hybrid Wood–Concrete Ceiling Elements
Authors: Bezama Alberto , Hildebrandt Jakob , Thrän Daniela
Published: April 2021

As bioeconomy strategies strive to integrate industrial sectors for achieving innovative materials alternative to the ones produced from non-renewable resources, the development of monitoring systems and tools to assess the implementation of such value chains is still a work in progress. This work intended to integrate the traditional life cycle assessment with a regionalized social life cycle assessment method to evaluate alternative production scenarios of a hybrid construction system with a wood-based lightweight concrete panel as a core component currently in its final stages of technical development. The life cycle impact assessment was carried out by comparing the relative advantages of two product development scenarios against the reference system’s results. The social life cycle assessment was carried out using the model “REgional SPecific cONtextualised Social life cycle Assessment” (RESPONSA), which was developed for assessing wood-based value chains under a regional scope. The results showed that both alternative scenarios present large advantages when compared to the reference system. Moreover, the implementation of the production value chain was found to imply positive socioeconomic advantages in the region, in particular, due to the quality of the jobs found in the organizations associated with the production system.
Pre-Service Early Childhood Educator Experience in a UNESCO Biosphere Reserve
Authors: Beery Thomas , Magntorn Ola
Published: April 2021

There has been significant interest in the values and benefits of early childhood nature experiences on children’s well-being and development. One aspect of studying the exposure of children to nature that requires more focus is the role played by early childhood educators. In particular, there is a need for early childhood environmental education training for pre-service educators. This study will explore the use of a UNESCO Biosphere Reserve as an outdoor classroom for early childhood environmental education pre-service professionals. Exploratory quantitative and qualitative descriptive data from a series of three short surveys (pre/post/delayed post) provide a basic overview of pre-service teacher perspectives, experiences, and outcomes of an environmental education intervention. The results indicate that the participating pre-service educators had little to no familiarity with the environmental concepts or the biosphere reserve site before participation in the intervention. The post-intervention and delayed post-intervention results show that pre-service educators perceived that their understanding of the concept had improved. The results also show a perception of the positive role that biosphere reserve sites can play in early childhood education. Three critical implications emerged from the overall quantitative and qualitative results: (1) specific support should be given for early childhood environmental education training; (2) biosphere reserve functions provide support for efforts to improve connections to nature; (3) early childhood education has the potential to support the broadening of the biosphere reserve audience.
Central Banks’ Monetary Policy in the Face of the COVID-19 Economic Crisis: Monetary Stimulus and the Emergence of CBDCs
Authors: Echarte Fernández Miguel Ángel , Náñez Alonso Sergio Luis , Jorge-Vázquez Javier , Reier Forradellas Ricardo Francisco
Published: April 2021

This article analyzes the monetary policy of major central banks during the economic crisis generated by the COVID-19 pandemic. Rising public debt in many countries is being financed through asset purchases by monetary authorities. Although these stimulus policies predate the pandemic, they have been significantly boosted as many governments face large financing needs. We have been in a low interest rate environment for years and some governments have issued debt securities at negative rates. In addition, the rise of decentralized cryptocurrencies, based on blockchain technology, has created greater competition in the international monetary system and many governments have considered the creation of centralized virtual currencies, known as central bank digital currencies (CBDCs). We will analyze some relevant cases, with an emphasis on the digital euro project. The methodology is based on the analysis of the evolution of monetary variables. Pearson’s correlation will be used to establish some relationships between them. There is a strong similarity in the expansionary monetary policies of central banks. Although the growth of the money supply has not been passed on to the CPI, it has been passed on to the financial markets and the price of assets such as Bitcoin or gold.
Torrefaction Thermogravimetric Analysis and Kinetics of Sorghum Distilled Residue for Sustainable Fuel Production
Authors: Yen Shih-Wei , Chen Wei-Hsin , Chang Jo-Shu , Eng Chun-Fong , Raza Naqvi Salman , Show Pau Loke
Published: April 2021

This study investigated the kinetics of isothermal torrefaction of sorghum distilled residue (SDR), the main byproduct of the sorghum liquor-making process. The samples chosen were torrefied isothermally at five different temperatures under a nitrogen atmosphere in a thermogravimetric analyzer. Afterward, two different kinetic methods, the traditional model-free approach, and a two-step parallel reaction (TPR) kinetic model, were used to obtain the torrefaction kinetics of SDR. With the acquired 92–97% fit quality, which is the degree of similarity between calculated and real torrefaction curves, the traditional method approached using the Arrhenius equation showed a poor ability on kinetics prediction, whereas the TPR kinetic model optimized by the particle swarm optimization (PSO) algorithm showed that all the fit qualities are as high as 99%. The results suggest that PSO can simulate the actual torrefaction kinetics more accurately than the traditional kinetics approach. Moreover, the PSO method can be further employed for simulating the weight changes of reaction intermediates throughout the process. This computational method could be used as a powerful tool for industrial design and optimization in the biochar manufacturing process.
Sustainable Learning in Education
Authors: Ben-Eliyahu Adar
Published: April 2021

This article presents a theoretical definition and conceptualization of sustainable learning in education (SLE). SLE is differentiated from teaching for sustainability or sustainable learning, which focuses on teaching ways to renew, rejuvenate, and reuse necessary resources, such as clean water. At its core, SLE consists of strategies and skills that enable learners to effectively renew, rebuild, reuse, inquire, be open-minded, and cope with challenging and complicated circumstances that require learning and relearning. Four aspects of SLE are described: (1) renewing and relearning; (2) independent and collaborative learning; (3) active learning; and (4) transferability. To further understand SLE, the self-regulated learning framework is used. This is an important and novel future direction for research and educational practice.
Investigation of Mixing Behavior of Hydrogen Blended to Natural Gas in Gas Network
Authors: Kong Mingmin , Feng Shuaiming , Xia Qi , Chen Chen , Pan Zhouxin , Gao Zengliang
Published: April 2021

Hydrogen is of great significance for replacing fossil fuels and reducing carbon dioxide emissions. The application of hydrogen mixing with natural gas in gas network transportation not only improves the utilization rate of hydrogen energy, but also reduces the cost of large-scale updating household or commercial appliance. This paper investigates the necessity of a gas mixing device for adding hydrogen to existing natural gas pipelines in the industrial gas network. A three-dimensional helical static mixer model is developed to simulate the mixing behavior of the gas mixture. In addition, the model is validated with experimental results. Parametric studies are performed to investigate the effect of mixer on the mixing performance including the coefficient of variation (COV) and pressure loss. The research results show that, based on the, the optimum number of mixing units is three. The arrangement of the torsion angle of the mixing unit has a greater impact on the COV. When the torsion angle θ = 120°, the COV has a minimum value of 0.66%, and when the torsion angle θ = 60°, the COV has a maximum value of 8.54%. The distance of the mixing unit has little effect on the pressure loss of the mixed gas but has a greater impact on the COV. Consecutive arrangement of the mixing units (Case A) is the best solution. Increasing the distance of the mixing unit is not effective for the gas mixing effect. Last but not least, the gas mixer is optimized to improve the mixing performance.
What Impacts Socially Responsible Consumption?
Authors: Ríos-Rodríguez María Luisa , Salgado-Cacho José María , Moreno-Jiménez Pilar
Published: April 2021

This study examines factors related to socially responsible consumption based on a sample of 636 Spanish consumers. The results indicate that socio-demographic factors such as sex, age, education level, and economic activity affect responsible consumption. In addition, it was found that in order to assess the antecedents of socially responsible consumption it is necessary to specify the type of consumer behavior (for example, purchasing specific products or initiatives against the purchase of certain products). It is found that perceived efficacy, affective commitment, and materialism explain different levels of variance in socially responsible consumption. Purchasing cause-related products is most influenced by affective commitment and perceived efficacy. Materialism affects purchasing motivated by firm behavior and the volume of consumption. The study finds that the referents to the responsibility that consumers adopt can be explained independently. In conclusion, with the aim of supporting a more sustainable society, the need for studies on anti-consumption behaviors as an instrument for sustainability is stressed.
Developing Generalised Equation for the Calculation of PayBack Period for Rainwater Harvesting Systems
Authors: Imteaz Monzur A. , Bayatvarkeshi Maryam , Karim Md. Rezaul
Published: April 2021

Many end-users for the stormwater harvesting systems are reluctant in implementing the system due to uncertainties of the potential returns for their investment for such system. A common practice of presenting potential benefit of a certain investment is through calculation of payback period using net annual benefit from the system. Traditional practice of doing such payback period analysis for rainwater tanks was considering individual building/roof, system volume, and specific investment cost. It is not feasible to conduct such analysis for each and every rainwater harvesting system installed in different buildings. To overcome this tedious practice, this study presents development of a generalised equation for the estimation of payback period for rainwater tanks based on roof area, initial cost, and rate of return. Based on an earlier study, several payback periods were calculated for different roof sizes, initial costs, and rate of return. It was found that all these variables can be correlated and embedded into a base equation of power function. Final developed equation results were compared with the payback periods calculated through traditional practice considering net annual savings and net present value of cumulative savings. It is found that the developed equation can estimate payback periods with very good accuracies; for all the selected internal rates of return correlation values ranging from 0.99 to 1.0 were achieved. Corresponding coefficient of determinations varied from 0.988 to 0.993. Furthermore, it is found that for a fixed roof area and rate of return, the payback period is having a power relationship (having an exponent less than 1.0) with the initial cost.
Seismic Performance of a Green Roof Structure
Authors: Tam Svetlana , Wong Jenna
Published: April 2021

Sustainability addresses the need to reduce the structure’s impact on the environment but does not reduce the environment’s impact on the structure. To explore this relationship, this study focuses on quantifying the impact of green roofs or vegetated roofs on seismic responses such as story displacements, interstory drifts, and floor level accelerations. Using an archetype three-story steel moment frame, nonlinear time history analyses are conducted in OpenSees for a shallow and deep green roof using a suite of ground motions from various distances from the fault to identify key trends and sensitivities in response.
Bayesian Approach to Analyze Reading Comprehension: A Case Study in Elementary School Children in Mexico
Authors: Rodriguez-Barrios Ernesto U. , Melendez-Armenta Roberto Angel , Garcia-Aburto Sandra G. , Lavoignet-Ruiz Marieli , Sandoval-Herazo Luis Carlos , Molina-Navarro Antonio , Morales-Rosales Luis Alberto
Published: April 2021

In the educational field, reading comprehension is connected to learning achievement, and through it, one can interpret, retain, organize and value what has been read. It is an essential ability for the understanding and processing of information in learning. Furthermore, it is an essential skill to developing sustainable education. In this sense, sustainable development needs an advanced reading comprehension ability at elementary school in order to teach and learn future knowledge areas such as climate change, disaster risk reduction, biodiversity, poverty reduction, and sustainable consumption. Nevertheless, there have been few works focused on analyzing reading comprehension, particularly in Mexico, where the reference is the Programme for International Student Assessment (PISA) test on how well the Mexican students have developed this skill. Hence, this article shows the usefulness of employing Bayesian techniques in the analysis of reading comprehension at elementary school. The Bayesian network model allows for the determination of the language and communication level of achievement based on parameters such as learning style, learning pace, speed, and reading comprehension, obtaining an 85.36% precision. Moreover, the results confirm that teachers could determine changes in lesson planning and implement new pedagogical mechanisms to improve the level of learning and understanding contents.
Unconventional SUSY and Conventional Physics: A Pedagogical Review
Authors: Alvarez Pedro D. , Delage Lucas , Valenzuela Mauricio , Zanelli Jorge
Published: April 2021

In supersymmetric extensions of the Standard Model, the observed particles come in fermion–boson pairs necessary for the realization of supersymmetry (SUSY). In spite of the expected abundance of super-partners for all the known particles, not a single supersymmetric pair has been reported to date. Although a hypothetical SUSY breaking mechanism, operating at high energy inaccessible to current experiments cannot be ruled out, this reduces SUSY’s predictive power and it is unclear whether SUSY, in its standard form, can help reducing the remaining puzzles of the standard model (SM). Here we argue that SUSY can be realized in a different way, connecting spacetime and internal bosonic symmetries, combining bosonic gauge fields and fermionic matter particles in a single gauge field, a Lie superalgebra-valued connection. In this unconventional representation, states do not come in SUSY pairs, avoiding the doubling of particles and fields and SUSY is not a fully off-shell invariance of the action. The resulting systems are remarkably simple, closely resembling a standard quantum field theory and SUSY still emerges as a contingent symmetry that depends on the features of the vacuum/ground state. We illustrate the general construction with two examples: (i) A 2 + 1 dimensional system based on the osp(2,2|2) superalgebra, including Lorentz and u(1) generators that describe graphene; (ii) a supersymmetric extension of 3 + 1 conformal gravity with an SU(2,2|2) connection that describes a gauge theory with an emergent chiral symmetry breaking, coupled to gravity. The extensions to higher odd and even dimensions, as well as the extensions to accommodate more general internal symmetries are also outlined.
Anderson Acceleration of the Arnoldi-Inout Method for Computing PageRank
Authors: Tang Xia , Wen Chun , Gu Xian-Ming , Shen Zhao-Li
Published: April 2021

Anderson(m0) extrapolation, an accelerator to a fixed-point iteration, stores m0+1 prior evaluations of the fixed-point iteration and computes a linear combination of those evaluations as a new iteration. The computational cost of the Anderson(m0) acceleration becomes expensive with the parameter m0 increasing, thus m0 is a common choice in most practice. In this paper, with the aim of improving the computations of PageRank problems, a new method was developed by applying Anderson(1) extrapolation at periodic intervals within the Arnoldi-Inout method. The new method is called the AIOA method. Convergence analysis of the AIOA method is discussed in detail. Numerical results on several PageRank problems are presented to illustrate the effectiveness of our proposed method.
Semi-Exponential Operators
Authors: Herzog Monika
Published: April 2021

In this paper we study approximation properties of exponential-type operators for functions from exponential weighted spaces. We focus on some modifications of these operators and we derive a new example of such operators. A probabilistic approach for these modifications is also demonstrated.
Saved by the Shell: Molecular Analysis Detects the Cryptic Sea Hare, Aplysia concava G. B. Sowerby I, 1833 (Mollusca: Heterobranchia: Aplysiidae), from Oceania, with a Redescription
Authors: Nimbs Matt J. , Wilson Nerida G.
Published: April 2021

A recent taxonomic revision split the circumglobal sea hare Aplysia parvula into 10 constituent taxa, of which only three are likely to be found in the Southern Pacific. This prompted an investigation of animals previously identified as A. parvula from Australia. Specimens collected from Eastern Australia and Hunter Island, east of New Caledonia, could not be satisfactorily identified with any of the currently accepted taxa based on morphological diagnostic features listed in the revision; however, the presence of a highly concave shell is diagnostic. Quantification of genetic divergence using Cytochrome Oxidase I (COI) supports the delineation of this species as a distinct taxon, and a phylogenetic reconstruction based on concatenated COI, 16S and H3 markers reveals a sister relationship with the newly described Aplysia ghanimii from the Atlantic and Western Indian Oceans and an undescribed species from Japan. As a result, the name Aplysia concava G. B. Sowerby, I, 1833 is resurrected for this species. As the original description was based solely on a shell, a redescription is provided here with photographs of living animals and microscope images of internal anatomical structures.