bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Evaluation of EMKEY: An Assistive Technology for People with Upper Limb Disabilities
Authors: Zapata Mireya , Valencia-Aragón Kevin , Ramos-Galarza Carlos
Published: April 2023

Assistive technology can help people with disabilities to use computers more effectively and can enable them to access the same information and resources as people without disabilities. To obtain more insight into the factors that can bring about the design of an Emulator of Mouse and Keyboard (EMKEY) to higher levels of user satisfaction, an experimental study was conducted in order to analyse its effectiveness and efficiency. The experimental study involved 27 participants (Mage = 20.81, SD = 1.14) who performed three experimental games under different conditions (using the mouse and using EMKEY with head movements and voice commands). According to the results, the use of EMKEY allowed for the successful performance of tasks such as matching stimuli (F(2,78) = 2.39, p = 0.10, η2 = 0.06). However, the execution times of a task were found to be higher when using the emulator to drag an object on the screen (t(52,1) = −18.45, p ≤ 0.001, d = 9.60). These results indicate the effectiveness of technological development for people with upper limb disabilities; however, there is room for improvement in terms of efficiency. The findings are discussed in relation to previous research and are based on future studies aimed at improving the operation of the EMKEY emulator.
Nonlinear Modeling of Contact Stress Distribution in Thin Plate Substrates Subjected to Aspect Ratio
Authors: Lv Chao , Wei Huixin , Lan Zhiwen , Wu Ping
Published: April 2023

The foundation substrate’s basal contact stresses are typically thought to have a linear distribution, although the actual form is nonlinear. Basal contact stress in thin plates is experimentally measured using a thin film pressure distribution system. This study examines the nonlinear distribution law of basal contact stresses in thin plates with various aspect ratios under concentrated loading, and it establishes a model for the distribution of contact stresses in thin plates using an exponential function that accounts for aspect ratio coefficients. The outcomes demonstrate that the thin plate’s aspect ratio significantly affects how the substrate contact stress is distributed during concentrated loading. The contact stresses in the thin plate’s base exhibit significant nonlinearity when the aspect ratio of the test thin plate is greater than 6~8. The aspect ratio coefficient-added exponential function model can better optimize the strength and stiffness calculations of the base substrate and more accurately describe the actual distribution of contact stresses in the base of the thin plate compared to linear and parabolic functions. The correctness of the exponential function model is confirmed by the film pressure distribution measurement system that directly measures the contact stress at the base of the thin plate, providing a more accurate nonlinear load input for the calculation of the internal force of the base thin plate.
TeCVP: A Time-Efficient Control Method for a Hexapod Wheel-Legged Robot Based on Velocity Planning
Authors: Sun Junkai , Sun Zezhou , Li Jianfei , Wang Chu , Jing Xin , Wei Qingqing , Liu Bin , Yan Chuliang
Published: April 2023

Addressing the problem that control methods of wheel-legged robots for future Mars exploration missions are too complex, a time-efficient control method based on velocity planning for a hexapod wheel-legged robot is proposed in this paper, which is named time-efficient control based on velocity planning (TeCVP). When the foot end or wheel at knee comes into contact with the ground, the desired velocity of the foot end or knee is transformed according to the velocity transformation of the rigid body from the desired velocity of the torso which is obtained by the deviation of torso position and posture. Furthermore, the torques of joints can be obtained by impedance control. When suspended, the leg is regarded as a system consisting of a virtual spring and a virtual damper to realize control of legs in the swing phase. In addition, leg sequences of switching motion between wheeled configuration and legged configuration are planned. According to a complexity analysis, velocity planning control has lower time complexity and less times of multiplication and addition compared with virtual model control. In addition, simulations show that velocity planning control can realize stable periodic gait motion, wheel-leg switching motion and wheeled motion and the operation time of velocity planning control is about 33.89% less than that of virtual model control, which promises a great prospect for velocity planning control in future planetary exploration missions.
Wideband RCS Reduction Based on Hybrid Checkerboard Metasurface
Authors: Zhao Zhiming , Li Xiaoping , Dong Guoxiang
Published: April 2023

Traditional stealth technologies all have their problems such as high cost and large thickness. To solve the problems, we used novelty checkerboard metasurface in stealth technology. Checkerboard metasurface does not have as high conversion efficiency as radiation converters, but it has many advantages such as small thickness and low cost. So it is expected to overcome the problems of traditional stealth technologies. Unlike other checkerboard metasurfaces, we improved it further by using two types of polarization converter units to be arranged in turn to form a hybrid checkerboard metasurface. Because the checkerboard metasurface composed of one type of polarization converter units can have a relatively wide radar cross-section (RCS) reduction in bandwidth when two types of polarization converter units are arranged in turn to form a hybrid checkerboard metasurface and mutual compensation of the two polarization converter units can broaden RCS reduction band further. Therefore, by designing the metasurface to be independent from the polarization, the effect of RCS reduction can be insensitive to the polarization of the incoming EM waves. The experiment and simulation results showed the value of this proposed hybrid checkerboard metasurface for RCS reduction. Mutual compensation of the units is a new attempt in the field of checkerboard metasurfaces for stealth technology and proved to be effective.
Evaluation of the Number of Degrees of Freedom of the Field Scattered by a 3D Geometry
Authors: Sekehravani Ehsan Akbari , Leone Giovanni , Pierri Rocco
Published: April 2023

The solution to an ill-posed linear inverse problem requires the use of regularization methods to achieve a stable approximation solution. One powerful approach is the truncated singular value decomposition (TSVD), but it requires an appropriate choice of the truncation level. One suitable option is to take into account the number of degrees of freedom (NDF) of the scattered field, which is defined by the step-like behavior of the singular values of the relevant operator. Then, the NDF can be estimated as the number of singular values preceding the knee or the exponential decay. Therefore, an analytical estimation of the NDF is significant for obtaining a stable, regularized solution. This paper addresses the analytical estimation of the NDF of the field scattered by the surface of a cube geometry for a single frequency and the multi-view case in the far-zone. In addition, a method is proposed to find the minimum numbers of plane waves and their directions to achieve the total estimated NDF. The main results are that the NDF is related to the measure of the surface of the cube and can be achieved by only considering a limited number of impinging plane waves. The efficiency of the theoretical discussion is demonstrated through a reconstruction application for microwave tomography of a dielectric object. Numerical examples are provided to confirm the theoretical results.
Exploring the Role of Gamification in the Online Shopping Experience in Retail Stores: An Exploratory Study
Authors: Lopes João M. , Gomes Sofia , Lopes Pedro , Silva Adriana , Lourenço Daniel , Esteves Duarte , Cardoso Mafalda , Redondo Valter
Published: April 2023

Online retail shops increasingly implement gamified marketing strategies to enrich consumers’ online experience and increase engagement. This study aims to evaluate the ludic experience of consumers in online retail stores and the role of gamification and game mechanics in changing the online shopping experience. It seeks to assess, through a qualitative methodology, based on an exploratory study approach obtained through 30 interviews with Portuguese consumers, whether consumers have playful experiences when shopping in online retail shops and whether the introduction of game mechanics changes this experience by generating co-creation. The results show that online shopping can be playful and generate positive emotional benefits. However, gamification in online retail shops is not guided by a co-creation process, nor do game mechanics create greater online consumer engagement. There is a need to review how gamification is introduced in online retail shops, and strategies should be designed to co-create experience value and brand co-creation. This study is original, as it contributes to developing knowledge about gamification in the context of the online retail experience. Studies on this topic are scarce, and this study contributes to filling that gap.
January 6th and De-Democratization in the United States
Authors: Castañeda Ernesto , Jenks Daniel
Published: April 2023

The events of January 6th were a clear example of threats to American democracy. De-democratization is a process that preceded Trump’s election and that can still be seen in the United States and around the world. Social theorist Charles Tilly wrote about how becoming a democracy is not a unidirectional, one-time event or goal, but a non-linear process. This paper analyzes developments in the United States that signal rises and falls in the level of democracy over the last several decades. It discusses Donald Trump’s rise to power, the insurrection on January 6th, 2021, and the state of inclusion of ethnoracial minorities in the United States. It uses Tilly’s proposed processes of democratization and de-democratization. This more nuanced understanding of democracy and state–society relations helps avoid celebratory stances about the promise of electoral politics as well as pessimistic assessments about the imminent arrival of fascism and authoritarianism.
Spatial and Temporal Patterns of Hydropower Development on the Qinghai–Tibet Plateau
Authors: Qin Chanyuan , Fu Bin , Zhu Xiaokang , Dunyu Duoji , Bianba Ciren , Baima Renzeng
Published: April 2023

The Qinghai–Tibet Plateau is rich in hydropower resources for China, and the development of these has an important impact on the sustainable development of the plateau. However, the research on the pattern and processes of hydropower development on the plateau is still lacking. Using both field investigation and collected data, we evaluated the density and intensity of hydropower development on the Tibetan Plateau over the past 40 years. The spatial and temporal patterns of hydropower development were analyzed by applying exploratory spatial data analysis methods to study the spatial aggregation of hydropower development on the Qinghai–Tibet Plateau since 1980. The results show that: (1) Hydropower development on the Qinghai–Tibet Plateau can be divided into four stages—(i) pre-1980, at the beginning of development, with a small number of power stations and a small installed capacity; (ii) the period from 1980 to 2005, which was dominated by small hydropower developments, and the number of hydropower stations increased seven-fold; (iii) the 2005–2014 period, which saw large-scale cascade development; and (iv) post-2014, when hydropower development mode changed from quantity-led to scale-led. (2) Significant differences in hydropower development areas on the Qinghai–Tibet Plateau regarding the density and intensity of development from east to west are constantly decreasing. (3) The increase in hydropower development density in the past 40 years is mainly due to the increasing aggregation effect of hydropower development absorption in the eastern region (the aggregation effect of western counties has not been shown). (4) While low hydropower development intensity is found in most areas of the Qinghai–Tibet Plateau, attention must be given to river protection problems in the eastern high-intensity areas; failure to do so will increase the aggregation effect of hydropower development aggregation and, ultimately, affect the sustainable development of the regional development of the Qinghai–Tibet Plateau.
Artificial Intelligence-Empowered Art Education: A Cycle-Consistency Network-Based Model for Creating the Fusion Works of Tibetan Painting Styles
Authors: Chen Yijing , Wang Luqing , Liu Xingquan , Wang Hongjun
Published: April 2023

The integration of Tibetan Thangka and other ethnic painting styles is an important topic of Chinese ethnic art. Its purpose is to explore, supplement, and continue Chinese traditional culture. Restricted by Buddhism and the economy, the traditional Thangka presents the problem of a single style, and drawing a Thangka is time-consuming and labor-intensive. In response to these problems, we propose a Tibetan painting style fusion (TPSF) model based on neural networks that can automatically and quickly integrate the painting styles of the two ethnicities. First, we set up Thangka and Chinese painting datasets as experimental data. Second, we use the training data to train the generator and the discriminator. Then, the TPSF model maps the style of the input image to the target image to fuse the two ethnicities painting styles of Tibetan and Chinese. Finally, to demonstrate the advancement of the proposed method, we add four comparison models to our experiments. At the same time, the Frechet Inception Distance (FID) metric and the questionnaire method were used to evaluate the quality and visual appeal of the generated images, respectively. The experimental results show that the fusion images have excellent quality and great visual appeal.
Smart Cities Maturity Model—A Multicriteria Approach
Authors: Aragão Franciely Velozo , Chiroli Daiane Maria de Genaro , Zola Fernanda Cavicchioli , Aragão Emanuely Velozo , Marinho Luis Henrique Nogueira , Correa Ana Lidia Cascales , Colmenero João Carlos
Published: April 2023

The concept of smart cities has gained relevance over the past few years. Public managers have been planning investments to turn their cities into smart cities. Maturity models can help managers to monitor the performance of urban indicators; however, these maturity models are not always capable of meeting their proposed goals. In this sense, this research aims to develop a maturity model that ranks the “smartness” of a city based on social and technological indicators. The Smart Cities Maturity Model (MMSC) variables were extracted from ISO’s 37153:2017, 37120:2018, 37107:2019. The MMSC is structured on a hybrid TOPSIS multicriteria decision-making method. In this paper, we modified TOPSIS and used it to generate a synthetic indicator, called smart index, that designates the level of maturity of a real city. For this change to be possible, we fixed some alternatives and changed the positive ideal and negative ideal solution. The methodology is proven to be very efficient in measuring the smart city maturity level, and it can be easily adapted for the upcoming ISOs.
A Noxious Weed Ambrosia artemisiifolia L. (Ragweed) as Sustainable Feedstock for Methane Production and Metals Immobilization
Authors: Havryliuk Olesia , Hovorukha Vira , Gladka Galyna , Tymoshenko Artem , Kyrylov Semen , Shabliy Oleksandra , Bida Iryna , Mariychuk Ruslan , Tashyrev Oleksandr
Published: April 2023

Plants of the Ambrosia genus are invasive and cause many ecological problems, including the oppression of the growth of agricultural crops and native plants, land depletion, and the production of strong allergens. The use of weeds as a sustainable feedstock for biogas production, either methane or hydrogen, is a promising way to fulfill the energy needs of the current generation, eliminate the depletion of non-renewable carbon resources, and preserve the ecosystem degradation caused by invasive species impacts. A diversified microbial community was used as inoculum and Ambrosia artemisiifolia L. biomass as a substrate for anaerobic degradation and methane production. In this regard, the development of biotechnological approaches to ragweed degradation will promote the integration of new renewable energy systems. Herein, we have shown the high effectiveness of combining the processes of anaerobic degradation of plant biomass for methane production and detoxification of meal-containing model sewage by a diversified microbial community. Thus, the maximum methane yield was 56.0 L kg−1 TS. The presence of 500 mg L−1 Cu(II) slightly inhibited methane synthesis, and the methane yield was 38.4 L kg−1 TS. In contrast to a diversified microbial community, the natural microbiome of ragweed almost did not synthesize methane and did not degrade plant biomass (Kd = 2.3). Methanogens effectively immobilized Cr(IV), Cu(II), and Fe(III) during ragweed fermentation at initial concentrations of 100–200 mg L−1. The obtained results showed the high effectiveness of applying a diversified microbial community in a sewage treatment plant for the degradation of a noxious plant, Ambrosia artemisiifolia L.
Optimization of A Procedure to Improve the Extraction Rate of Biologically Active Compounds in Red Grape Must Using High-Power Ultrasound
Authors: Maier Alina , Padureanu Vasile , Lupu Mirabela Ioana , Canja Cristina Maria , Badarau Carmen , Padureanu Cristina , Alexa Ersilia , Poiana Mariana-Atena
Published: April 2023

The primary focus in the production of quality red wine is the extraction of grape components, which can be achieved in a variety of ways. This work investigates the extraction yield of biologically active compounds from crushed Merlot grapes, as a result of ultrasound treatment applied before maceration, and optimizes the process parameters of a laboratory scale using response surface methodology (RSM) within a central composite design (CCD) model. The two factors whose response was studied were amplitude (A) % and treatment time (t), while the dependent variables were the total phenolic compounds (TPC), monomeric anthocyanins (MA), and antioxidant activity expressed as ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity. The results showed that the application of high-power ultrasound treatment to crushed grapes for a few minutes increased both the extraction rate of bioactive compounds and the antioxidant activity by a maximum of 12 times for the TPC, 14 times for the MA, 3.6 times for the FRAP value, and 18.77% for the DPPH. The optimized solution had an amplitude of 90% and a treatment time of 4 min and 24 s. The validation experiments yielded errors between—8.70% and 3.14%, confirming the proposed model. Thus, the RSM model is recommended as a tool to optimize a procedure for enhancing both the extraction rate of the bioactive compounds from grapes and the antioxidant properties of grape must. Our results demonstrate the ultimate benefits of using ultrasonic treatment on crushed grapes at the beginning of the winemaking process, as a highly effective technique for improving the extraction of high-value bioactive chemicals, with significant application potential.
Evaluating Developer Responses to App Reviews: The Case of Mobile Banking Apps in Saudi Arabia and the United States
Authors: Alismail Maymunah Abdullatif , Albesher Abdulmohsen Saud
Published: April 2023

Application stores (app stores) enable developers to interact with users by responding to their reviews. Many developers continuously monitor user reviews and seek to respond to them effectively and efficiently to boost user satisfaction, which in the end increases the app’s rating. Thus, it is essential to study developer responses and how to improve them. This research was aimed at evaluating developer responses to user reviews in both the Apple App Store and Google Play Store in the banking domain. Ten Saudi and ten United States (U.S.) bank apps were selected from each store as the sample. Quantitative and qualitative approaches were employed to code and categorize developer responses for each app using content analysis. The study found that developers’ responses can be divided into three types of interaction: interactive response, semi-interactive response, and no response. A main finding is that responses by U.S. bank app developers outperformed those by Saudi bank app developers in terms of the number and quality of responses. This research provides valuable recommendations for users, developers, and app stores to enhance user–developer interaction.
Climate Change, Sustainable Forest Management, ICT Nexus, and the SDG 2030: A Systems Thinking Approach
Authors: Empig Ernesto E. , Sivacioğlu Ahmet , Pacaldo Renato S. , Suson Peter D. , Lavilles Rabby Q. , Teves Maria Rizalia Y. , Ferolin Maria Cecilia M. , Amparado Ruben F.
Published: April 2023

The 2030 global agenda for sustainable development integrates social, economic, and environmental dimensions, emphasizing peace, human rights, gender equality, and women’s empowerment. The SDG framework, consisting of 17 goals, 169 targets (SDTs), and 231 indicators (SDIs), forms a complex, interconnected network that necessitates extensive research. Despite prior studies on SDG interlinkages, the integration of Climate Change (CC), Sustainable Forest Management (SFM), and Information and Communication Technology (ICT), collectively known as CSI Nexus, remains underexplored. This study addresses this gap by identifying SDTs aligned with CC, SFM, and ICT (CSI) and analyzing their linkages within the SDG framework using a systems thinking approach. The objectives are to (1) investigate and identify SDTs connected with the CSI Nexus and (2) assess the significant relationship between and among CC, SFM, and ICT. The primary method involves a simplified meta-analysis and systems thinking approach incorporating content analysis, network visualization, affiliation matrix mapping, frequency distributions, and Spearman’s rho correlation. Results reveal 56 SDTs directly connected within CC + SFM + ICT, 16 within CC + SFM, one within SFM + ICT, and 51 within ICT + CC. The analysis indicates CC is significantly associated with SFM, while ICT has no significant association with CC and SFM, asserting minimal influence of ICT and SFM on the SDG 2030 framework. This research provides significant insights for decision-makers and stakeholders, contributing as a science-informed guide for priority-setting, policy coherence, and decision-making supporting the 2030 Sustainable Development Goals across sectors.
Measuring the Sustainable Development of Marine Economy Based on the Entropy Value Method: A Case Study in the Yangtze River Delta, China
Authors: Ni Xiaowei , Quan Yongbo
Published: April 2023

The rapid growth of the marine economy has provided a strong impetus for the economic development of the Yangtze River Delta region, but it has also posed serious challenges to the ecological environment of the marine watersheds in which it is located. To investigate how to promote the sustainable development of the marine economy in the Yangtze River Delta region, this study used relevant statistical data from 2009 to 2019, combined with four factors—marine economy, marine resources, ecological environment, and scientific and technological innovation—to build an evaluation index system for the sustainable development of the marine economy and employed the entropy value method to conduct a deeper investigation. It was found that there are problems in the sustainable development of the Yangtze River Delta marine economy, such as imperfect marine industry structure, significant differences in resource allocation, insufficient support capacity of marine science and technology innovation, and insufficient ecological environmental protection. Therefore, the study suggests promoting regional collaboration in the Yangtze River Delta, improving technological innovation, and enhancing environmental protection to support the sustainable development of the regional marine economy.
Exploring the Spatiotemporal Heterogeneity of Carbon Emission from Energy Consumption and Its Influencing Factors in the Yellow River Basin
Authors: Zhang Shumin , Lv Yongze , Xu Jian , Zhang Baolei
Published: April 2023

Scientific estimation and dynamic monitoring on the heterogeneity of carbon emission from energy consumption (CEEC) is the basis for formulating and implementing regional carbon reduction strategies to realize the goal of carbon neutrality and high-quality development. This study analyzes the temporal and spatial differences of CEEC and its driving factors in the Yellow River Basin (YRB) from 2000 to 2018 based on the Log-Mean Divisia Index (LMDI) time decomposition method and the multi-regional (M-R) space decomposition method. The results indicate the following: The amount of CEEC of the YRB increased greatly from 2000 to 2012, and then expressed a convergence trend after 2012, with obvious spatial differences. The economic development is the leading factor that promotes the increase in CEEC in the YRB, energy intensity is the main force for the reduction in CEEC, and their influencing effectiveness varies significantly in different periods and provinces. Spatially, the larger economic development in Shandong, Henan, and Sichuan causes the higher level of CEEC, and the regulation of energy intensity in Shanxi, Ningxia, and Inner Mongolia is important for the reduction in their CEEC. The impact effectiveness of economic structure and energy structure on CEEC in the YRB is relatively weak, and they are potential factors for the reduction in CEEC. Therefore, the corresponding emission reduction measures in nine provinces of the YRB should focus on reducing energy intensity, building a green energy system, and strengthening “green” economic development to achieve high-quality development in the YRB. This study is designed to explore the spatiotemporal variations and influencing factors of carbon emissions in the nine provinces of the YRB, which is of great significance for achieving low-carbon development in the region.
Design of Pressure Energy-Absorbing FRP Anchors and Numerical Analysis of Mechanical Properties
Authors: Tang Zhi , Chang Dezhi , Cai Xiaoqiao , Lyu Jinguo , Wu Hao
Published: April 2023

Conventional FRP anchor rods have low elongation and poor impact resistance, both of which do not meet the support requirements of rock burst roadways. Therefore, a pressure energy-absorbing FRP anchor rod composed of an FRP rod body, tray, energy-absorbing sleeve and round table nut was designed. Numerical simulations were carried out to study the mechanical properties of the FRP anchor rod in static tension and impact tension, and to compare its mechanical properties with those of conventional FRP anchor rods. The results show that the pressure energy-absorbing FRP anchor rod is stretched in four stages: the front-elastic stage, constant resistance to compression, the back-elastic stage and damage, with an additional constant resistance to compression stage compared with conventional FRP anchors. The elongation, energy absorption and impact resistance time of the pressure energy-absorbing FRP anchor rods are greater than those of conventional FRP anchor rods, and the mechanical properties of the pressure energy-absorbing FRP anchor rods are better than those of conventional FRP anchor rods. As the impact velocity increases, the energy absorption rate of the pressure energy-absorbing FRP anchor increases non-linearly. The impact energy and impact velocity have less influence on the breaking load, elongation and energy absorption of pressure energy-absorbing FRP anchor rods. The research results can provide a theoretical basis for the application and parameter design of the pressure energy-absorbing FRP anchor rod, and provide support for the safe and efficient mining of the mine.
The Role of High Nature Value Farmland for Landscape and Soil Pollution Assessment in a Coastal Delta in China Based on High-Resolution Indicators
Authors: Song Yingqiang , Zhang Zeao , Li Yan , Zou Runyan , Wang Lu , Yang Hao , Hu Yueming
Published: April 2023

High nature value farmland (HNVf) plays an important role in improving biodiversity and landscape heterogeneity, and it is effective in curbing soil non-point source pollution and carbon loss in sustainable eco-agricultural systems. To this end, we developed high-resolution (2 m × 2 m) indicators for the identification of potential HNVf based on GF1B remote sensing imaging, including the land cover (LC), normalized difference vegetation index (NDVI), Shannon diversity (SH), and Simpsons index (SI). The statistical results for LC with high resolution (2 m × 2 m) showed that there was 41.05% of intensive farmland in the study area, and the pixel proportion of the HNVf map (above G3) was 44.30%. These HNVf patches were concentrated in the transition zone around the edge of the intensive farmland and around rivers, with characteristics of HNVf type 2 being significantly reflected. Among the real-life areas from Map World, elements (i.e., linear forests, rivers, and semi-natural vegetation etc.) of HNVf accounted for more than 70% of these regions, while a field survey based on potential HNVf patches also exhibited significant HNVf characteristics in comparison with intensive farmlands. In addition, from 2002 to 2020, the total migration distance of the gravity center of intensive farmland in the study area was 7.65 km. Moreover, four landscape indices (patch COH index, landscape division index, SH, and SI) slowly increased, indicating that the species richness and biodiversity were improved. It was also found that a series of ecological protection policies provide effective guarantees for an improvement in species diversity and the development of HNVf in the study area. In particular, the average contents of As, Cr, Cu, Ni, and Zn in the HNVf were 20.99 mg kg−1, 121.11 mg kg−1, 21.97 mg kg−1, 29.34 mg kg−1, and 41.68 mg kg−1, respectively, which were lower in comparison with the intensive farmland soil. This is the first HNVf exploration for landscape and soil pollution assessment in a coastal delta in China, and could provide powerful guidance for the ecological protection of farmland soil and the high-quality development of sustainable agriculture.
Research on Spatial Correlation Evolution of Marine Ecological Efficiency Based on Social Network and Spatial Correlation Matrix Model
Authors: Zhang Yihua , Li Xinyu , Wang Yuan
Published: April 2023

Most developed countries in the world are maritime powers. This article constructs an ecological efficiency evaluation system based on the characteristics of the ocean itself while taking into account the relationship between land and sea. Based on social network analysis, the relationship between China’s marine ecological efficiency is regarded as a social network system, and the roles and positions played by 11 coastal cities in the network are analyzed from a relational perspective. Next, based on the unexpected super efficiency model to measure the ocean efficiency value in China’s coastal areas, we explore its spatiotemporal evolution characteristics, and measure the ocean ecological efficiency while incorporating ecological environmental pollution as an unexpected output into the evaluation system. Then, the spatial incidence matrix of marine ecological efficiency is calculated through the modified gravity model, and the characteristics of network structure are described with the help of the social network method. In addition, ArcGIS software is used to visualize the spatial evolution process. Finally, QAP regression is used to explore the key factors affecting the spatial correlation network of marine ecological efficiency in China. The results show the following: (1) In terms of time, the marine eco-efficiency of most provinces is not high, and the difference between provinces is obvious, but on the whole, it shows a fluctuating upward trend. (2) From the perspective of space, the overall displacement of the center of marine eco-efficiency in China is large in the north–south direction and small in the east–west direction, and the center of marine eco-efficiency is always concentrated near the Yangtze River Delta. (3) On the whole, the spatial correlation network of China’s marine eco-efficiency is becoming more and more complex. The number of correlation relationships and network density is increasing, and the network framework is gradually maturing. The spatial adjacency matrix, the difference in economic development level, and the difference in population distribution level can significantly promote the formation and development of the spatial correlation network of marine eco-efficiency. However, the differences in the level of opening to the outside world and in the structure of marine industries restrain their spatial networks. The difference between marine science and technology levels is not significant.
Factors Affecting the High-Intensity Cooling Distance of Urban Green Spaces: A Case Study of Xi’an, China
Authors: Sun Mingjun , Zhao Xinyi , Wang Yun , Ren Zeqi , Fu Xin
Published: April 2023

Urban green space has a cooling effect and its cooling effect can extend to the surrounding environment, conspicuously decreasing with distance. Land surface temperature (LST) and cooling distance are generally researched based on remote sensing and temperature inversion algorithms; this distance is affected by internal and external environment factors, but the high-intensity cooling distance (HCD) is overlooked by using large scale datasets. In addition, the comprehensive relationship between internal and external factors with cooling distance and HCD is still unclear. The aim of this study is to identify the HCD of green spaces by monitoring the changes of LST away from it and to quantify the influences of 12 internal and external factors on HCD. A multiple linear regression model is used to analyze the relationship between them. In the summer of 2022, we measured and calculated HCD for 59 urban green spaces in Xi’an, China. The analysis results show that the HCD is not only affected by the internal landscape factors of green spaces, but also closely related to factors associated with the natural environmental, urban attributes, and surrounding structures. These findings can rationally assist the planning of the allocation of urban green spaces and provide a scientific basis for mitigating the urban heat island effect.
Dynamic Equilibrium of Sustainable Ecosystem Variables: An Experiment
Authors: Perroni Marcos Gonçalves , da Veiga Claudimar Pereira , Su Zhaohui , Ramos Fernando Maciel , da Silva Wesley Vieira
Published: April 2023

Developing indicators to monitor the dynamic equilibrium of sustainable ecosystem variables has been challenging for policymakers, companies, and researchers. The new method matrix decomposition analysis (MDA) is an adaptation of the Leontief input–output equations for the disaggregated structural decomposition of key performance indicators (KPI). The main problem that this work addresses is related to the behavior of MDA when compared to traditional methodologies such as data envelopment analysis (DEA) and stochastic frontier analysis (SFA). Can MDA be considered robust enough for wide applicability? To compare the models, we developed a methodology called marginal exponentiation experiments. This approach is a type of simulation that raises the inputs and outputs of an entity to a marginal power, thus making it possible to compare a large number of models with the same data. RMarkdown was used for methodological operationalization, wherein data science steps are coded in specific chunks, applying a layered process with modeling. The comparison between the models is operationalized in layers using techniques such as descriptive statistics, correlation, cluster, and linear discriminant analysis (LDA). Given the results, we argue that MDA is a Leontief partial equilibrium model that produces indicators with dual interpretation, enabling the measurement of the dynamic equilibrium of sustainable ecosystem variables. Furthermore, the method offers a new ranking system that detects relative changes in the use of resources correlated with efficiency analysis. The practical value for decision-makers relates to the fact that we found evidence that MDA can be considered robust enough to identify whether a given ecosystem is in equilibrium and that the excessive use of resources or abnormal productivity can cause instability.
Effects of Successive Planting of Eucalyptus Plantations on Tree Growth and Soil Quality
Authors: Dai Qiongling , Wang Tianhui , Wei Penglian , Fu Yunlin
Published: April 2023

The ultra-short-cycle successive planting of Eucalyptus plantations has caused environmental and social problems, and changing the rotation cycle is a very good option to solve this issue. However, the effects of successive planting on Eucalyptus growth and soil quality after changing the cultivation period are unclear. This study evaluated the effects of successive Eucalyptus planting on growth, soil nutrients, and bacterial and fungal community structure with an eight-year cultivation period. Eucalyptus plantations with different succession generations (first, second and third generation) were selected, and tree height and diameter at breast height were measured. Ten indicators of soil nutrients in different soil layers (0–20 cm and 20–40 cm) were measured, and soil bacteria and fungi were sequenced in high throughput. Results show that there is an upward trend in tree growth after three successive generations, reaching the highest timber yield in the third-generation plantation. Soil nutrients also showed changes, in the 0–20 cm soil layer, with decreased TN, NH4+-N, NO3−-N and AK and increased AP, particularly for OM and TP content. In the 20–40 cm soil layer, the content of NH4+-N and NO3−-N increased slightly and the soil’s OM, TP, and TK content increased significantly. The diversity of bacterial and fungal communities in different soil layers increased significantly, and the community structure composition changed. Bacterial and fungal community structures were mainly driven by pH, NH4+-N, TP and AP factors and by OM, NH4+-N, TP and TK factors, respectively. Thus, successive plantings of Eucalyptus plantations with a cultivation period of eight years is conducive to the growth of trees. Some nutrients of the soil were returned, and the soil microbial diversity increased. Successive planting has brought efficiency and economic benefits while maintaining the soil’s fertility.
Configuration Optimization of Hydrogen-Based Multi-Microgrid Systems under Electricity Market Trading and Different Hydrogen Production Strategies
Authors: Lu Zhiming , Li Youting , Zhuo Guying , Xu Chuanbo
Published: April 2023

Hydrogen-based multi-microgrid systems (HBMMSs) are beneficial for energy saving and emission reductions. However, the optimal sizing of HBMMSs lacks a practical configuration optimization model and a reasonable solution method. To address these problems, we designed a novel structure of HBMMSs that combines conventional energy, renewable energy, and a hydrogen energy subsystem. Then, we established a bi-level multi-objective capacity optimization model while considering electricity market trading and different hydrogen production strategies. The objective of the inner model, which is the minimum annual operation cost, and the three objectives of the outer model, which are the minimum total annual cost (TAC); the annual carbon emission (ACE); and the maximum self-sufficiency rate (SSR), are researched simultaneously. To solve the above optimization model, a two-stage solution method, which considers the conflicts between objectives and the objectivity of objective weights, is proposed. Finally, a case study is performed. The results show that when green hydrogen production strategies are adopted, the three objectives of the best configuration optimization scheme are USD 404.987 million, 1.106 million tons, and 0.486, respectively.
Estimating the Cost of Wave Energy Converters at an Early Design Stage: A Bottom-Up Approach
Authors: Giglio Enrico , Petracca Ermando , Paduano Bruno , Moscoloni Claudio , Giorgi Giuseppe , Sirigu Sergej Antonello
Published: April 2023

The role of ocean energy is expected to grow rapidly in the coming years, and techno-economic analysis will play a crucial role. Nowadays, despite strong assumptions, the vast majority of studies model costs using a top-down approach (the TdA) that leads to an unrepresentative economic model. WEC developers usually go through the the TdA approach because more detailed cost data are not available at an earlier design stage. At a very advanced design stage, some studies have also proposed techno-economic optimisation based on the bottom-up approach (BuA). This entails that the detailed cost metrics presented in the literature are very specific to the WEC type (hence not applicable to other cases) or unrepresentative. This lack of easily accessible detailed cost functions in the current state of the art leads to ineffective optimisations at an earlier stage of WEC development. In this paper, a BuA for WECs is proposed that can be used for techno-economic optimisation at the early design stage. To achieve this goal, cost functions of most common components in the WEC field are retrieved from the literature, exposed, and critically compared. The large number of components considered allows the results of this work to be applied to a vast pool of WECs. The novelty of the presented cost functions is their parameterization with respect to the technological specifications, which already enables their adoption in the design optimisation phase. With the goal of quantifying the results and critically discuss the differences between the TdA and the BuA, the developed methodology and cost functions are applied to a case study and specifically adopted for the calculation of the capital cost of PeWEC (pendulum wave energy converter). In addition, a hybrid approach (HyA) is presented and discussed as an intermediate approach between the TdA and the BdA. Results are compared in terms of capital expenditure (CapEx) and pie cost distribution: the impact of adopting different cost metrics is discussed, highlighting the role that reliable cost functions can have on early stage technology development. This paper proposes more than 50 cost functions for WEC components. Referring to the case study, it is shown that while the total cost differs only slightly (11%), the pie distribution changes by up to 22%. Mooring system and power take-off are the cost items where the TdA and the HyA differ more from the BuA cost estimate.
Building Up a Sustainable Path to Maritime Security: An Analytical Framework and Its Policy Applications
Authors: Li Lingqun
Published: April 2023

Maritime security is currently a buzzword in international relations. The popularity of the term reflects an emerging consensus across the international community recognizing increasing challenges to world oceans and helps to rally support for serious efforts to cope with these challenges. However, the term is highly contested with regard to its conceptual meaning and empirical implications. The discipline of security studies provides a critical perspective revealing the state-centered ontology embedded in many of the discussions of maritime security. The complicated and intertwining nature of maritime threats in today’s world oceans demands a systematic analytical framework to comprehend and address them, a framework that moves beyond statist ontology, military means, and zero-sum mentality to a people-centered, diversified toolkit and positive-sum mentality and opens space for a common, cooperative, and comprehensive security agenda. The evolving discourse on human security and sustainable development sheds light on a possible path to approach such an agenda in an effective and sustainable manner. It has also enlightened the mandates of major international institutions and a lot of states practices in the pursuit of maritime security. Against this background, this article aims to explore the conception of maritime security and provide an analytical framework for analyzing and guiding maritime security practices and explores a feasible path towards realizing sustainable maritime security that can meet the diversified challenges emerging in global maritime space today. To this end, the article draws on the discipline of security studies over the past few decades so as to structure a rigorous analytical tool for engaging maritime security as a theoretical concept and a set of policy objectives. Applying this framework to state practices, this article discusses the case of China, examining, on the one hand, China’s understanding of maritime security and related policy practices and, on the other hand, exploring the value of the proposed policy framework as serving the foundation for bridging disagreements, forging consensus, and coordinating policy actions in the pursuit of sustained security and development in the maritime domain.
Evaluating the Effect of Curing Time and Resting Time on Moisture Damage Resistance of Asphalt Mixtures Using the Pull-Off Tensile Strength (POTS) Test
Authors: Nimsanor Adulwit , Chaturabong Preeda
Published: April 2023

This article explores the effectiveness of the Pull-off Tensile Strength (POTS) test as a tool for evaluating the moisture damage resistance of asphalt mixtures. Currently, indirect tensile strength (ITS) and the Hamburg Wheel Tracking (HWT) test are used, but they have limitations such as expensive equipment and being heavy. The POTS test is a low-cost and portable alternative. This study investigated the effect of curing time and resting time on the POTS of asphalt-aggregate systems by subjecting samples to different curing times and resting times before testing their tensile strength under dry and wet conditions. The results show that the tensile strength decreases with increasing curing time or exposure to water, indicating that the debonding process between asphalt and aggregates occurs more rapidly with aging. The tensile strength ratio (TSR) of the POTS test for all three asphalt binder types increases with resting time and curing time, with the highest values observed at a curing time of 2 h and a resting time of 5–15 min. Additionally, this study found a strong linear relationship between the tensile strength ratios of ITS and POTS tests, regardless of curing time and resting time. Overall, the POTS test is a promising alternative for evaluating moisture damage resistance in asphalt mixtures.
Research on Excavator Trajectory Control Based on Hybrid Interpolation
Authors: Yang Jing , Gao Yingjie , Guo Rui , Gao Qingshan , Zhao Jingyi
Published: April 2023

In this study, to address the issues of tooth tip operation discontinuity and jitter during autonomous excavator operation, a multi-segment mixed interpolation method utilizing different higher-order polynomials has been proposed. This approach is designed to optimize the tooth tip trajectory of the excavator under multiple constraints, resulting in a smoother trajectory. Specifically, the single-bucket excavator was chosen as the research object, and three different high-order mixed polynomials were utilized to interpolate the trajectory of the digging discrete points. Through a comparative analysis under multiple constraints, this study explored and analyzed the joint angle, angular velocity, and angular acceleration curves of each excavator’s joint. An experimental platform was established to investigate the hydraulic system of an excavator, and the optimal trajectory was controlled using a high-order mixed polynomial interpolation. The results of this study demonstrate that the tracking accuracy of the excavator’s actuator under the optimal interpolation strategy is high, with a maximum displacement deviation of ±3 mm. Additionally, during operation, the excavator manipulator runs smoothly and continuously with minimal flexible impact and vibration.