bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface Velocity Analysis of Surge Region of Karayaylak Glacier from 2014 to 2020 in the Pamir Plateau
Authors: Peng Yanfei , Li Zhongqin , Xu Chunhai , Zhang Hui , Han Weixiao
Published: February 2021

The west branch of Karayaylak Glacier (eastern Pamir Plateau) surged in May 2015, significantly impacting on local socio-economic development. This event was also of great significance for studies of surging glaciers. Using Sentinel-1 imagery analyzed by offset tracking, based on normalized cross-correlation (NCC), and with the support of the Google Earth Engine (GEE) platform, we quantified the ice surface velocity of the west branch and terminus of Karayaylak Glacier from 13 October 2014 to 17 October 2020. Sentinel-1 images were acquired at intervals of 12 or 24 days. We also used a three-dimensional (3-D) laser scanner to measure the velocity of 3 ablation stakes and 56 feature points in the study region from 15 August to 6 October 2015, for the purpose of accuracy assessment. We set up an automatic meteorological station to record the air temperature in the same period and combined this with data from Tashkurgan meteorological station from 1957 to 2015. Analysis of this dataset provided insights into the glacier surge mechanism, with the following conclusions. (1) Surface velocity of the west branch and terminus of Karayaylak Glacier increased sharply after October 2014. The velocity then dropped significantly in the two months after the surge, and stayed at low values for nearly a year. After 2017, the velocity was slightly higher than in the previous period. (2) The surge event occurred from 11 April to 17 May 2015; the average surface velocity in this phase attained 2395 m a−1 with a maximum velocity of 4265 m a−1 at the west branch terminus. (3) From 2017 to 2020, the velocity showed periodic annual changes. (4) Based on the meteorological data analysis, we conclude that this surge resulted from the interaction between thermal and hydrological control mechanisms. Simultaneously, we demonstrate the high potential of the GEE platform and Sentinel-1 data to extract glacier surface velocity.
Initial Assessment of Galileo Triple-Frequency Ambiguity Resolution between Reference Stations in the Hong Kong Area
Authors: Li Yangyang , Shen Mingxing , Yang Lei , Deng Chenlong , Tang Weiming , Zou Xuan , Wang Yawei , Zhang Yongfeng
Published: February 2021

The European Global Navigation Satellite System Galileo is gradually deploying its constellation. In order to provide reliable navigation and position services, the effectiveness and reliability of ambiguity resolution between reference stations is necessary in network real-time kinematic (NRTK). The multifrequency signal of Galileo could much enhance the ambiguity resolution (AR) reliability and robustness. In this study, to exploit full advantage of this, the geometry-free (GF) TCAR and ionospheric-free (IF) triple-carrier ambiguity resolution (TCAR) methods were utilized in solving the ambiguity in the Hong Kong area, which is an ionosphere disturbance active area, and compared with each other. The IF TCAR method was then used to combine multi-systems to improve Galileo E1 AR performance, which is named as the combined IF (CIF) TCAR method. Three experiments were carried out in the Hong Kong area and the results showed that the Galileo-only system could fix ambiguities on all satellite pairs correctly and reliably by the IF TCAR method, while the GF TCAR method showed a weaker performance. The wide-lane (WL) convergence time of the IF TCAR method is improved by about 37.6%. The IF TCAR method with respect to the GF TCAR method could improve the WL accuracy by 21.6% and the E1 accuracy by 72.7%, respectively. Compared with GPS-only TCAR or Galileo-only TCAR, the ambiguity accuracy and the convergence time of the CIF TCAR method, which combines GPS and Galileo, could be improved by about 25.7% and 47.1%, respectively.
Use of Time-Series NDWI to Monitor Emerging Archaeological Sites: Case Studies from Iraqi Artificial Reservoirs
Authors: Titolo Andrea
Published: February 2021

Over the last 50 years, countries across North Africa and the Middle East have seen a significant increase in dam construction which, notwithstanding their benefits, have endangered archaeological heritage. Archaeological surveys and salvage excavations have been carried out in threatened areas in the past, but the formation of reservoirs often resulted in the permanent loss of archaeological data. However, in 2018, a sharp fall in the water level of the Mosul Dam reservoir led to the emersion of the archaeological site of Kemune and allowed for its brief and targeted investigation. Reservoir water level change is not unique to the Mosul Dam, but it is a phenomenon affecting most of the artificial lakes of present-day Iraq. However, to know in advance which sites will be exposed due to a decrease in water level can be a challenging task, especially without any previous knowledge, field investigation, or high-resolution satellite image. Nonetheless, by using time-series medium-resolution satellite images, combined to obtain spectral indexes for different years, it is possible to monitor “patterns” of emerging archaeological sites from three major Iraqi reservoirs: Mosul, Haditha and Hamrin lake. The Normalised Difference Water Index (NDWI), generated from annual composites of Landsat and Sentinel-2 images, allow us to distinguish between water bodies and other land surfaces. When coupled with a pixel analysis of each image, the index can provide a mean for highlighting whether an archaeological site is submerged or not. Moreover, using a zonal histogram algorithm in QGIS over polygon shapefiles that represent a site surface, it is possible to assess the area of a site that has been exposed over time. The same analyses were carried out on monthly composites for the year 2018, to assess the impact of monthly variation of the water level on the archaeological sites. The results from both analyses have been visually evaluated using medium-resolution true colour images for specific years and locations and with 3 m resolution Planetscope images for 2018. Understanding emersion “patterns” of known archaeological sites provides a useful tool for targeted rescue excavation, while also expanding the knowledge of the post-flooding impact on cultural heritage in the regions under study.
Machine Learning Comparison and Parameter Setting Methods for the Detection of Dump Sites for Construction and Demolition Waste Using the Google Earth Engine
Authors: Zhou Lei , Luo Ting , Du Mingyi , Chen Qiang , Liu Yang , Zhu Yinuo , He Congcong , Wang Siyu , Yang Kun
Published: February 2021

Machine learning has been successfully used for object recognition within images. Due to the complexity of the spectrum and texture of construction and demolition waste (C&DW), it is difficult to construct an automatic identification method for C&DW based on machine learning and remote sensing data sources. Machine learning includes many types of algorithms; however, different algorithms and parameters have different identification effects on C&DW. Exploring the optimal method for automatic remote sensing identification of C&DW is an important approach for the intelligent supervision of C&DW. This study investigates the megacity of Beijing, which is facing high risk of C&DW pollution. To improve the classification accuracy of C&DW, buildings, vegetation, water, and crops were selected as comparative training samples based on the Google Earth Engine (GEE), and Sentinel-2 was used as the data source. Three classification methods of typical machine learning algorithms (classification and regression trees (CART), random forest (RF), and support vector machine (SVM)) were selected to classify the C&DW from remote sensing images. Using empirical methods, the experimental trial method, and the grid search method, the optimal parameterization scheme of the three classification methods was studied to determine the optimal method of remote sensing identification of C&DW based on machine learning. Through accuracy evaluation and ground verification, the overall recognition accuracies of CART, RF, and SVM for C&DW were 73.12%, 98.05%, and 85.62%, respectively, under the optimal parameterization scheme determined in this study. Among these algorithms, RF was a better C&DW identification method than were CART and SVM when the number of decision trees was 50. This study explores the robust machine learning method for automatic remote sensing identification of C&DW and provides a scientific basis for intelligent supervision and resource utilization of C&DW.
A Critical Analysis of Red Ceramic Blocks Roughness Estimation by 2D and 3D Methods
Authors: Arnold Daiana Cristina Metz , de Oliveira Valéria Costa , Kazmierczak Claudio de Souza , Tonietto Leandro , Menegotto Camila Werner , Gonzaga Luiz , André da Costa Cristiano , Veronez Maurício Roberto
Published: February 2021

The method of measuring the roughness of ceramic substrates is not consensual, with unsuccessful attempts to associate roughness with the adhesion of coatings because the ceramic blocks have different areas of contact, shapes, and dimensions of the roughness as well as the extrusion process influences the mechanical anisotropy of the block. The goal of this work is a quantification and comparison of roughness data obtained by 2D and 3D methods, evaluating the variations of results between the measurement methods and formulating a critical analysis regarding the quality of the information obtained with each method. For this propose, four sets of ceramic blocks with different firing temperature were produced, in order to provide groups of blocks with different surface topographies in which the roughness was estimated. The roughness measurements were made in 4608 regions, resulting in 1536 values using 2D method and 3072 values using 3D method. In the 2D method for ceramic blocks, the measurement orientation strongly influences the result, depending on the measurement position and orientation. The 3D method generates a higher average value and allows to identify roughness variations typical of the ceramic block. The roughness estimation of a ceramic block surface must be done using the 3D method.
Remote Sensing of Atmospheric Hydrogen Fluoride (HF) over Hefei, China with Ground-Based High-Resolution Fourier Transform Infrared (FTIR) Spectrometry
Authors: Yin Hao , Sun Youwen , Liu Cheng , Wang Wei , Shan Changgong , Zha Lingling
Published: February 2021

Remote sensing of atmospheric hydrogen fluoride (HF) is challenging because it has weak absorption signatures in the atmosphere and is surrounded by strong absorption lines from interfering gases. In this study, we first present a multi-year time series of HF total columns over Hefei, China by using high-resolution ground-based Fourier transform infrared (FTIR) spectrometry. Both near-infrared (NIR) and mid-infrared (MIR) solar spectra suites, which are recorded following the requirements of Total Carbon Column Observing Network (TCCON) and Network for the Detection of Atmospheric Composition Change (NDACC), respectively, are used to retrieve total column of HF (THF) and column-averaged dry-air mole fractions of HF (XHF). The NIR and MIR observations are generally in good agreement with a correlation coefficient (R) of 0.87, but the NIR observations are found to be (6.90 ± 1.07 (1σ)) pptv, which is lower than the MIR observations. By correcting this bias, the combination of NIR and MIR observations discloses that the XHF over Hefei showed a maximum monthly mean value of (64.05 ± 3.93) pptv in March and a minimum monthly mean value of (45.15 ± 2.93) pptv in September. The observed XHF time series from 2015 to 2020 showed a negative trend of (−0.38 ± 0.22) % per year. The variability of XHF is inversely correlated with the tropopause height, indicating that the variability of tropopause height is a key factor that drives the seasonal cycle of HF in the stratosphere. This study can enhance the understanding of ground-based high-resolution remote sensing techniques for atmospheric HF and its evolution in the stratosphere and contribute to forming new reliable remote sensing data for research on climate change.
Modeling and Analysis of BDS-2 and BDS-3 Combined Precise Time and Frequency Transfer Considering Stochastic Models of Inter-System Bias
Authors: Jiao Guoqiang , Song Shuli , Chen Qinming , Huang Chao , Su Ke , Wang Zhitao , Cheng Na
Published: February 2021

BeiDou global navigation satellite system (BDS) began to provide positioning, navigation, and timing (PNT) services to global users officially on 31 July, 2020. BDS constellations consist of regional (BDS-2) and global navigation satellites (BDS-3). Due to the difference of modulations and characteristics for the BDS-2 and BDS-3 default civil service signals (B1I/B3I) and the increase of new signals (B1C/B2a) for BDS-3, a systemically bias exists in the receiver-end when receiving and processing BDS-2 and BDS-3 signals, which leads to the inter-system bias (ISB) between BDS-2 and BDS-3 on the receiver side. To fully utilize BDS, the BDS-2 and BDS-3 combined precise time and frequency transfer are investigated considering the effect of the ISB. Four kinds of ISB stochastic models are presented, which are ignoring ISB (ISBNO), estimating ISB as random constant (ISBCV), random walk process (ISBRW), and white noise process (ISBWN). The results demonstrate that the datum of receiver clock offsets can be unified and the ISB deduced datum confusion can be avoided by estimating the ISB. The ISBCV and ISBRW models are superior to ISBWN. For the BDS-2 and BDS-3 combined precise time and frequency transfer using ISBNO, ISBCV, ISBRW, and ISBWN, the stability of clock differences of old signals can be enhanced by 20.18%, 23.89%, 23.96%, and 11.46% over BDS-2-only, respectively. For new signals, the enhancements are −50.77%, 20.22%, 17.53%, and −3.69%, respectively. Moreover, ISBCV and ISBRW models have the better frequency transfer stability. Consequently, we recommended the optimal ISBCV or suboptimal ISBRW model for BDS-2 and BDS-3 combined precise time and frequency transfer when processing the old as well as the new signals.
Robust Template Adjustment Siamese Network for Object Visual Tracking
Authors: Tang Chuanming , Qin Peng , Zhang Jianlin
Published: February 2021

Most of the existing trackers address the visual tracking problem by extracting an appearance template from the first frame, which is used to localize the target in the current frame. Unfortunately, they typically face the model degeneration challenge, which easily results in model drift and target loss. To address this issue, a novel Template Adjustment Siamese Network (TA-Siam) is proposed in this paper. The proposed framework TA-Siam consists of two simple subnetworks: The template adjustment subnetwork for feature extraction and the classification-regression subnetwork for bounding box prediction. The template adjustment module adaptively uses the feature of subsequent frames to adjust the current template. It makes the template adapt to the target appearance variation of long-term sequence and effectively overcomes model drift problem of Siamese networks. In order to reduce classification errors, the rhombus labels are proposed in our TA-Siam. For more efficient learning and faster convergence, our proposed tracker uses a more effective regression loss in the training process. Extensive experiments and comparisons with trackers are conducted on the challenging benchmarks including VOT2016, VOT2018, OTB50, OTB100, GOT-10K, and LaSOT. Our TA-Siam achieves state-of-the-art performance at the speed of 45 FPS.
Predictive Maintenance and Intelligent Sensors in Smart Factory: Review
Authors: Pech Martin , Vrchota Jaroslav , Bednář Jiří
Published: February 2021

With the arrival of new technologies in modern smart factories, automated predictive maintenance is also related to production robotisation. Intelligent sensors make it possible to obtain an ever-increasing amount of data, which must be analysed efficiently and effectively to support increasingly complex systems’ decision-making and management. The paper aims to review the current literature concerning predictive maintenance and intelligent sensors in smart factories. We focused on contemporary trends to provide an overview of future research challenges and classification. The paper used burst analysis, systematic review methodology, co-occurrence analysis of keywords, and cluster analysis. The results show the increasing number of papers related to key researched concepts. The importance of predictive maintenance is growing over time in relation to Industry 4.0 technologies. We proposed Smart and Intelligent Predictive Maintenance (SIPM) based on the full-text analysis of relevant papers. The paper’s main contribution is the summary and overview of current trends in intelligent sensors used for predictive maintenance in smart factories.
Cortical Effects of Noisy Galvanic Vestibular Stimulation Using Functional Near-Infrared Spectroscopy
Authors: Valdés Bulmaro A. , Lajoie Kim , Marigold Daniel S. , Menon Carlo
Published: February 2021

Noisy galvanic vestibular stimulation (nGVS) can improve different motor, sensory, and cognitive behaviors. However, it is unclear how this stimulation affects brain activity to facilitate these improvements. Functional near-infrared spectroscopy (fNIRS) is inexpensive, portable, and less prone to motion artifacts than other neuroimaging technology. Thus, fNIRS has the potential to provide insight into how nGVS affects cortical activity during a variety of natural behaviors. Here we sought to: (1) determine if fNIRS can detect cortical changes in oxygenated (HbO) and deoxygenated (HbR) hemoglobin with application of subthreshold nGVS, and (2) determine how subthreshold nGVS affects this fNIRS-derived hemodynamic response. A total of twelve healthy participants received nGVS and sham stimulation during a seated, resting-state paradigm. To determine whether nGVS altered activity in select cortical regions of interest (BA40, BA39), we compared differences between nGVS and sham HbO and HbR concentrations. We found a greater HbR response during nGVS compared to sham stimulation in left BA40, a region previously associated with vestibular processing, and with all left hemisphere channels combined (p < 0.05). We did not detect differences in HbO responses for any region during nGVS (p > 0.05). Our results suggest that fNIRS may be suitable for understanding the cortical effects of nGVS.
Distributed Architecture for Unmanned Vehicle Services
Authors: Ramos João , Ribeiro Roberto , Safadinho David , Barroso João , Rabadão Carlos , Pereira António
Published: February 2021

The demand for online services is increasing. Services that would require a long time to understand, use and master are becoming as transparent as possible to the users, that tend to focus only on the final goals. Combined with the advantages of the unmanned vehicles (UV), from the unmanned factor to the reduced size and costs, we found an opportunity to bring to users a wide variety of services supported by UV, through the Internet of Unmanned Vehicles (IoUV). Current solutions were analyzed and we discussed scalability and genericity as the principal concerns. Then, we proposed a solution that combines several services and UVs, available from anywhere at any time, from a cloud platform. The solution considers a cloud distributed architecture, composed by users, services, vehicles and a platform, interconnected through the Internet. Each vehicle provides to the platform an abstract and generic interface for the essential commands. Therefore, this modular design makes easier the creation of new services and the reuse of the different vehicles. To confirm the feasibility of the solution we implemented a prototype considering a cloud-hosted platform and the integration of custom-built small-sized cars, a custom-built quadcopter, and a commercial Vertical Take-Off and Landing (VTOL) aircraft. To validate the prototype and the vehicles’ remote control, we created several services accessible via a web browser and controlled through a computer keyboard. We tested the solution in a local network, remote networks and mobile networks (i.e., 3G and Long-Term Evolution (LTE)) and proved the benefits of decentralizing the communications into multiple point-to-point links for the remote control. Consequently, the solution can provide scalable UV-based services, with low technical effort, for anyone at anytime and anywhere.
Multi-Filter Decoding in WiFi Backscatter Communication
Authors: Boateng Nti Richard , Yun Ji-Hoon
Published: February 2021

WiFi backscatter communication has emerged as a promising enabler of ultralow-power connectivity for Internet of things, wireless sensor network and smart energy. In this paper, we propose a multi-filter design for effective decoding of WiFi backscattered signals. Backscattered signals are relatively weak compared to carrier WiFi signals and therefore require algorithms that filter out original WiFi signals without affecting the backscattered signals. Two multi-filter designs for WiFi backscatter decoding are presented: the summation and delimiter approaches. Both implementations employ the use of additional filters with different window sizes to efficiently cut off undesired noise/interference, thus enhancing frame detection and decoding performance, and can be coupled with a wide range of decoding algorithms. The designs are particularly productive in the frequency-shift WiFi backscatter communication. We demonstrate via prototyping and testbed experiments that the proposed design enhances the performance of various decoding algorithms in real environments.
Crustal Density Structure of the Jiuzhaigou Ms7.0 Earthquake Area Revealed by the Barkam–Jiuzhaigou–Wuqi Gravity Profile
Authors: Yang Guangliang , Shen Chongyang , Tan Hongbo , Wang Jiapei
Published: February 2021

The Barkam–Jiuzhaigou–Wuqi gravity profile extends across the Jiuzhaigou Ms7.0 earthquake (in 2017) zone and passes through several historical big earthquakes’ zones. We have obtained Bouguer gravity anomalies along the profile composed of 365 gravity observation stations with Global Positioning System (GPS) coordinates, analyzed the observed data and inverted subsurface density structure. The results show that the Moho depth has a big lateral variation from southwest to northeast, which shallows from 57 km to 43 km with maximum variation up to 14 km within 800 km. The most acute depth change of the Moho is in the boundary region between the Bayan Har block and West Qinling–Qilian block. According to our analysis, it is related to the eastward movement of the Bayan Har block. There are three main pieces of evidence that support it: (1) Density is higher in the east of the Bayan Har block and smaller in the west, which is the same as seismic activity; (2) Two thin low-density layers exist in the upper and middle crust of the Bayan Har block, which may promote inter-layer slip and the Jiuzhaigou Ms7.0 earthquake occurred in the boundary area of the two low-density layers, where the crustal density and Moho surface fluctuate sharply; (3) the GPS velocity field in the southwestern part gravity profile is significantly larger than that of the northeastern part, which is consistent with the density structure. Our studies also suggest that the large undulation of the Moho prevents the movement of the Bayan Har block, and strain is prone to accumulate here. The dynamic background analysis of the crust in this area indicates that the Moho surface uplifts in the West Qinling–Qilian block, which decelerates the eastern migration of material on the Qinghai–Tibet Plateau, and leads to the weak tectonic activity of the north part of the Bayan Har block.
Understanding Police Officers’ Usage of High-Visibility Safety Apparel: The Role of Safety Ethics and Professional Appearance
Authors: Kim Mijin , Song Christina Soyoung
Published: February 2021

High-visibility safety apparel (HVSA) is personal protective clothing that provides visual conspicuity to reduce police officers’ risk of fatality or injury from road traffic accidents. Under the current U.S. Department of Transportation’s Federal Highway Administration regulations, police officers on or near Federal-Aid highways are mandated to wear HVSA to enhance their visibility. Although wearing HVSA can significantly prevent traffic-related fatalities among police officers, studies have shown that they do not consistently, or ever, wear it. This study identifies factors influencing HVSA noncompliance among officers by exploring their perceptions of its use and efficiency. Ninety-eight police officers completed a field survey in four cities in Yavapai County, Arizona; their responses were analyzed via predictive decision tree modeling. The results indicated that officers’ HVSA-wearing behavior can be predicted by safety ethics, professional appearance, occupation risk, functionality of HVSA, and safety education. Among these predictors, safety ethics and professional appearance were the most important factors in forecasting officers’ HVSA-wearing behavior. Our study contributes to enhancing knowledge about the psychological aspects of officers’ HVSA-wearing behavior and provides implications for improving their traffic safety policies and compliance in the law enforcement community.
Choose Where You Live Carefully: Built Environment Differences in Children’s Cardiorespiratory Fitness and Cardiometabolic Risk
Authors: Nevill Alan M. , Reuter Cézane Priscila , Brand Caroline , Gaya Anelise Reis , Mota Jorge , Pollo Renner Jane Dagmar , Duncan Michael J.
Published: February 2021

Information regarding urban-rural differences in health indicators are scarce in Brazil. This study sought to identify rural-urban differences in cardiorespiratory fitness (CRF) and cardiometabolic risk (CMR) in Brazilian children and adolescents whilst controlling for the important confounding variables including social economic status (SES). This is a cross-sectional study developed with children and adolescents (n = 2250, age 11.54 ± 2.76) selected from a city in the south of Brazil. CRF was estimated using a 6-minute run/walk test. CMR scores were calculated by summing different cardiometabolic risk indicators. CRF was analysed assuming a multiplicative model with allometric body-size components. CMR differences in residential locations was assessed using Analysis of caovariance (ANCOVA) adopting SES, Body Mass Index (BMI), waist circumference (WC), age and fitness as covariates. Results indicated a main effect of location (p < 0.001) with children living a rural environment having the highest CRF, and children living in the periphery of towns having the lowest. Analysis also revealed significant main effects of location (p < 0.001) with children living a rural environment having the lowest CMR and children living in the centre of towns having the highest. Therefore, Brazilian children living in a rural environment appear to have superior health benefits.
Cumulative Median Estimation for Sufficient Dimension Reduction
Authors: Babos Stephen , Artemiou Andreas
Published: February 2021

In this paper, we present the Cumulative Median Estimation (CUMed) algorithm for robust sufficient dimension reduction. Compared with non-robust competitors, this algorithm performs better when there are outliers present in the data and comparably when outliers are not present. This is demonstrated in simulated and real data experiments.
Bluetooth Beacon-Based Mine Production Management Application to Support Ore Haulage Operations in Underground Mines
Authors: Park Sebeom , Choi Yosoon
Published: February 2021

In this study, a mine production management application (app) using a Bluetooth beacon and tablet PC was developed to support the efficient operation of an underground mine loading-transport system. The app receives signals from the Bluetooth beacons attached to major loading points and crushing sites through the tablet PC mounted on the truck and records the time the signals were received as well as the location of the truck. In addition, when the tablet PC receives the signal from the Bluetooth beacon, the truck driver can select and input information such as loading point, ore type, and dumping method on the tablet PC screen. Data recorded on the tablet PC during the haulage operation are automatically transmitted to the cloud server when the truck arrives in a wireless communication area. The cloud server continuously stores and manages data transmitted from multiple trucks equipped with tablet PCs. The performance test was conducted by using the system developed for a limestone underground mine located in Jeongseon, Korea. Results confirmed that the information related to ore production in the field could be effectively collected and managed, and the efficiency of production management could be improved.
Does Information about Personal Emissions of Carbon Dioxide Improve Individual Environmental Friendliness? A Survey Experiment
Authors: Yamashita Hideki , Kyoi Shinsuke , Mori Koichiro
Published: February 2021

The purpose of this study is to identify factors that can change the environmental friendliness of individuals in the context of climate change issues in terms of values, beliefs, controllability, concern, attitude, intention, and behavior through a survey experiment, and to test the hypothesis that providing information about the amount of carbon dioxide (CO2) emissions attributable to an individual with its threshold value motivates him/her to reduce that amount using statistical analyses (the Mann–Whitney test) and multivariate regressions (the ordered logit model). It is crucial to change the behavior of individuals as well as organizations to reduce the emissions of CO2 for solving climate change issues, because the aggregate amount of individual CO2 emissions is too large to ignore. We conducted a survey experiment to detect factors affecting the environmental friendliness of individuals. Subjects of the experiment were 102 students at Shiga University in Japan. They were randomly provided with communication opportunities, information about individual or group CO2 emissions, and information about their threshold value. The finding is that provision of information about the amount of individual and group CO2 emissions may be able to improve that person’s environmental friendliness in terms of values, beliefs, concern, attitude, intention, and behavior.
Boomtown Urbanization and Rural-Urban Transformation in Mining and Conflict Regions in Angola, the DRC and Zambia
Authors: Udelsmann Rodrigues Cristina , Mususa Patience , Büscher Karen , Cuvelier Jeroen
Published: February 2021

Starting from temporary settlements turning into permanent urban centers, this paper discusses the transformations taking place through the process of so-called ‘boomtown’ urbanization in Central and Southern Africa. Based on data collected in Angola, Zambia and the Democratic Republic of Congo, the paper identifies the different conditions for migration and settlement and the complex socio-economic, spatial, as well as political transformations produced by the fast growth and expansion of boomtowns. Different historical and contemporary processes shape boomtown urbanization in Africa, from colonial territorial governance to large- and small-scale mining or dynamics of violence and forced displacement. As centers of attraction, opportunities, diversified livelihoods and cultures for aspiring urbanities, boomtowns represent an interesting site from which to investigate rural-urban transformation in a context of resource extraction and conflict/post conflict governance. They equally represent potential catalyzing sites for growth, development and stability, hence deserving not only more academic but also policy attention. Based on the authors’ long-term field experience in the countries under study, the analysis draws on ethnographic fieldwork data collected through observations as well as interviews and focus group discussions with key actors involved in the everyday shaping of boomtown urbanism. The findings point to discernible patterns of boomtown consolidation across these adjacent countries, which are a result of combinations of types of migration, migrants’ agency and the governance structures, with clear implications for urban policy for both makeshift and consolidating towns.
Usefulness of Network Analysis to Characterize Technology Leaders in Small Dual-Purpose Cattle Farms in Mexico
Authors: Villarroel-Molina Oriana , De-Pablos-Heredero Carmen , Rangel Jaime , Vitale María Prosperina , García Antón
Published: February 2021

The low technology adoption rate is one of the major problems in very small dual-purpose cattle farms in Mexico. Using the social network analysis approach, we characterized the farmer leaders in the innovation network and deepened the knowledge on the low technological adoption causes. The sample consisted of 383 very small farms of dual-purpose cattle characterized by using nine reproductive management technologies. Our findings suggested that the network position of farmers had a significant impact on the technological level. Hence, the farmers farthest from the technology leaders showed the lowest levels of betweenness centrality index and high rates of constraint. Apart from this, advice, productive orientation, and intensification were also differentiating elements at the technological level. The findings provided relevant insights and useful tools to policy makers to better support, coordinate and enhance the adoption of innovation among smallholders.
Excellence in Sustainable Management in a Changing Environment
Authors: Manresa Alba , Escobar Rivera Dalilis
Published: February 2021

In the current changing environment, organizations need to evolve from a profitable perspective to a more sustainable focus. To deal with this change, the implementation of specific quality models and principles might help. Thus, the present article aims to study whether sustainable management can be achieved in specific organizations (enterprises, associations, and government institutions) by identifying the EFQM principles. Moreover, it analyses which of these quality principles positively and directly impacts the performances studied (environmental, social, and economic). To achieve these objectives, Ordinal Logistic Regression (ORL) was performed using data corresponding to the sample compiled by the Càtedra Universitària de Responsabilitat Social (RSU) from University of Girona. The research results indicate that implementing specific quality principles all the dimensions improved; thus, the organization becomes more sustainable. The value of this research lies in its contribution to the sustainable management literature; adds knowledge to the ongoing debate about the possible influence of TQM principles on the specific dimensions of sustainable management and highlight the importance of having a clear strategy to obtain the highest sustainable performance.
Life Cycle Assessment and Economic Energy Efficiency of a Solar Thermal Installation in a Family House
Authors: Košičan Jaroslav , Pardo Picazo Miguel Ángel , Vilčeková Silvia , Košičanová Danica
Published: February 2021

Designing solar strategies is a powerful step forward to set up an adequate residential house in terms of energy. Many types of research have simulated the energy needs for residential buildings. Designing an improper installation can contribute to a growth in the overall energy expenditure in ensuring thermal comfort. The use of solar thermal processes in Slovakia is on a rise as compared to recent years. This study models twelve solar water heating systems created on the roof of the household. Solar energy techniques are carried out to comply with the demands of heating and domestic hot water. The analysis deals with the most efficient alternative for the arranged solar systems of the building. Considering these installations and the corresponding overall prices of machinery, the best workable alternative is selected. The potential energy performance of auxiliary heating and the energy output of the solar thermal installation are examined. The required amounts of the different energy contributions are modelled and simulated in specific software for a family house in Kosice, Slovakia. We determine the limits of the design for an apartment and analyse which procedure is used to provide the typical average water expenditure and heating need, covering a multi-criteria analysis considering costs, energy, and life cycle analysis of every installation. This approach can support professionals to decide the best scheme considering these criteria, and this method can be satisfactorily applied. In these conditions, converting a conventional gas boiler into a solar thermal system involves monthly economic savings of around EUR 140–250, with payback periods of 2.5–7 years. The energy requirements are fully covered by the solar thermal schemes and the life cycle assessment resulted in reasonable impacts on the environment.
Professional Clubs as Platforms in Multi-Sided Markets in Times of COVID-19: The Role of Spectators and Atmosphere in Live Football
Authors: Herold Elisa , Boronczyk Felix , Breuer Christoph
Published: February 2021

In-stadium spectators affect the emotional value and atmosphere of sport live broadcasts. Due to the COVID-19 pandemic, in Europe, the presence of in-stadium spectators, however, was suspended until further notice. Conceptualizing professional clubs as economic platforms, network effects due to the lack of in-stadium spectators may affect stakeholders’ utility. Thus, the main aims of this study are to examine the influence of missing in-stadium spectators for professional clubs by investigating network effects on (1) TV viewers’ emotional arousal and (2) TV viewers’ attention towards sponsor messages during live football broadcasts. Using a quantitative research design, a controlled lap was conducted, and broadcasts were presented to n = 26 highly involved participants. Heart rate, eye-tracking, and betting odds data served as measurements of arousal, attention, and game outcome uncertainty and were aggregated on a second-by-second basis (k = 140,400). Multilevel regression analysis showed significant differences in viewers’ arousal and attention to sponsors, contingent on the presence of in-stadium spectators and game outcome uncertainty. The presence of in-stadium spectators increased arousal, while attention towards sponsor messages decreased, depending on game outcome uncertainty. Based on the presence of network effects, implications to sustainably adapting professional football clubs’ business models based on stakeholders’ different interests can be given.
Explicit Value at Risk Goal Function in Bi-Level Portfolio Problem for Financial Sustainability
Authors: Stoilov Todor , Stoilova Krasimira , Vladimirov Miroslav
Published: February 2021

The mean-variance (MV) portfolio optimization targets higher return for investment period despite the unknown stochastic behavior of the future asset returns. That is why a risk is explicitly considering, quantified by algebraic characteristics of volatilities and co-variances. A new probabilistic definition of portfolio risk is the Value at Risk (VaR). The paper makes explicit inclusion and minimization of VaR as a quantitative measure of financial sustainability of a portfolio problem. Thus, the portfolio weights as problem solutions will respect not only the MV requirements for risk and return, but also the additional minimization of risk defined by VaR level. The portfolio problem is defined in a new, bi-level form. The upper level minimizes and evaluates the VaR value. The lower level evaluates the optimal assets weights by minimizing portfolio risk and maximizing the return in MV form. The bi-level model allows to have extended set of portfolio solutions with the portfolio weights and the value of VaR. Graphical interpretation of this bi-level definition of the portfolio problem explains the differences with the MV portfolio definition. Thus, the bi-level portfolio problem evaluates the optimal weights, which makes maximization of portfolio return and minimization of the risk in its algebraic and probabilistic form of definition.
The Digital Competence of Pre-Service Educators: The Influence of Personal Variables
Authors: Cabezas-González Marcos , Casillas-Martín Sonia , García-Peñalvo Francisco José
Published: February 2021

Currently, 21st century students need competences that enable them to adapt to a new type of individual information and individual knowledge relationship, and, therefore, the education system should contemplate new ways for learners to develop in accordance with this so-called information and knowledge society. One of special importance is so-called digital competency. This article presents the results of a research study to determine the influence that the variables of gender, age, and academic degree have on the acquisition of digital competence by pre-service educators, with a sample of 370 students from different education degrees from the University of Salamanca (Spain). A quantitative methodology was used, employing a non-experimental method and the electronic survey technique to collect information on the dimensions of knowledge, as well as the management of and attitude towards information and communication technologies (ICTs). Data were analyzed inferentially from a comparison of means using nonparametric tests. This analysis was completed with the incorporation of Receiver Operating Characteristic (ROC) curves, which allowed us to graphically verify the differences between the subsamples and thus compare the different groups in relation to the proposed dimensions. The main conclusion was that the three variables studied can be considered as influential, though not determinant, in the acquisition of digital competency.
Optimization and Decision of Supply Chain Considering Negative Spillover Effect and Service Competition
Authors: Wu Yucai , Wang Jiguang , Chen Lu
Published: February 2021

Excellent service plays a vital role in the sustainability of enterprise and supply chains development in today’s increasingly fierce market competition. However, due to the inevitable spillover effect in the competitive network, enterprises’ initiative to improve the service level is reduced. From the perspective of negative spillover effect, optimization and decision-making in the competitive network of retailer-dominated supply chain are examined in this study. Considering four competitive situations in practical operation management, the corresponding double-layer compound nested Stackelberg game models are constructed, and the optimal equilibrium solutions are derived. Employing comprehensive comparison and analysis of the results, it is found that when the negative spillover effect of service increases, the optimal profit and service level of the leading supply chain or its retailers decrease, and the optimal retail price and overall optimal profit also gradually decline. For the leading supply chain, the centralized decision-making can achieve higher profits, and also more willing to improve the level of service. However, for the following supply chain, when the negative spillover effect of service is weak, the optimal service level under decentralized decision is higher, while when the spillover effect of service is strong, the optimal service level under integrated decision is higher. In addition, the supply chain-to-chain competition can bring negative incentives to the retailer that provides services, while for the rival that does not provide services, it can generate a certain free-riding effect that benefits them, and the effect is enhanced with the increase of competition.
Scoring Sufficiency Economy Philosophy through GRI Standards and Firm Risk: A Case Study of Thai Listed Companies
Authors: Korphaibool Veerawin , Chatjuthamard Pattanaporn , Treepongkaruna Sirimon
Published: February 2021

The purpose of this study is to evaluate sufficiency economy philosophy (SEP) performance through annual reports and voluntary sustainable development reports and examines the relationship between SEP performance and firm-specific risk of Thai listed companies from 2013 to 2018. Based on global reporting initiative (GRI) standards, the SEP performance was measured by aligning each GRI topic with each of the SEP elements to create an SEP scoring system. The scoring system was applied and tested by evaluating 34 firms for six years. The outcome scores were recorded in panel data structure and used to test two competing hypotheses of risk reduction and managerial opportunism. The regression results supported the risk reduction hypothesis and thus practicing SEP reduced firm-specific risk. Since our sample was limited to 34 firms, a two-stage least squares instrumental variable (2SLS-IV) analysis was performed to estimate the causal relationship between SEP performance and firm-specific risk. The result remained negatively and significantly correlated, indicating that SEP practice stimulated business sustainability. The finding suggested that the SEP scoring system was able to capture SEP performance and practicing SEP appeared to reduce firm-specific risk, which was consistent with the risk reduction hypothesis of the stakeholder theory.
Study of the Training of Environmentalists through Gamification as A University Course
Authors: Fernández Paz , Ceacero-Moreno Matías
Published: February 2021

The United Nations Agenda for 2030 lists Sustainable Development Goals which include quality education, which we have pursued in the Undergraduate Final Project of the Environmental Sciences Degree at the University of Granada (Spain). This entailed designing sustainable cities, including the management of natural hazards. We created an innovative didactic model using gamification, in which the student adopted the researcher role using the computer game Cities: Skylines as a simulation tool. Using a design-based method, we conducted a qualitative single-case study in which the professor observed the process and guided the student’s self-learning in a fun way. Under this guidance, the student made decisions alone in order to simulate a sustainable city, and afterwards to analyse the findings. Three variables were considered in order to evaluate the results concerning the quality of the student’s learning: (1) the experiment using the game, (2) motivation, and (3) the skills acquired. In all three, the student earned a high score. Of the 12 skills established as the specific goals of the teaching plan, the student reached a very high level in 10, and a high level in two, implying the overall success of the learning process. The study achieved its main goal, as an innovative didactic methodology was established based on student’s research, using gamification and simulation with a technological tool. Moreover, the case study gave positive results, with the student proving capable of developing scientific and professional competencies at an optimal level.