bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal Access Point Power Management for Green IEEE 802.11 Networks
Authors: Garroppo Rosario G. , Nencioni Gianfranco , Tavanti Luca , Gendron Bernard , Scutellà Maria Grazia
Published: March 2021

In this paper, we present an approach and an algorithm aimed at minimising the energy consumption of enterprise Wireless Local Area Networks (WLANs) during periods of low user activity. We act on two network management aspects: powering off some Access Points (APs), and choosing the level of transmission power of each AP. An efficient technique to allocate the user terminals to the various APs is the key to achieving this goal. The approach has been formulated as an integer programming problem with nonlinear constraints, which comes from a general but accurate characterisation of the WLAN. This general problem formulation has two implications: the formulation is widely applicable, but the nonlinearity makes it NP-hard. To solve this problem to optimality, we devised an exact algorithm based on a customised version of Benders’ decomposition method. The computational results proved the ability to obtain remarkable power savings. In addition, the good performance of our algorithm in terms of solving times paves the way for its future deployment in real WLANs.
Pipeline Monitoring Using Highly Sensitive Vibration Sensor Based on Fiber Ring Cavity Laser
Authors: Lalam Nageswara , Lu Ping , Venketeswaran Abhishek , Buric Michael P.
Published: March 2021

A vibration fiber sensor based on a fiber ring cavity laser and an interferometer based single-mode-multimode-single-mode (SMS) fiber structure is proposed and experimentally demonstrated. The SMS fiber sensor is positioned within the laser cavity, where the ring laser lasing wavelength can be swept to an optimized wavelength using a simple fiber loop design. To obtain a better signal-to-noise ratio, the ring laser lasing wavelength is tuned to the maximum gain region biasing point of the SMS transmission spectrum. A wide range of vibration frequencies from 10 Hz to 400 kHz are experimentally demonstrated. In addition, the proposed highly sensitive vibration sensor system was deployed in a field-test scenario for pipeline acoustic emission monitoring. An SMS fiber sensor is mounted on an 18” diameter pipeline, and vibrations were induced at different locations using a piezoelectric transducer. The proposed method was shown to be capable of real-time pipeline vibration monitoring.
Quantifying Step Count and Oxygen Consumption with Portable Technology during the 2-Min Walk Test in People with Lower Limb Amputation
Authors: Smith John D. , Guerra Gary
Published: March 2021

Step counts and oxygen consumption have yet to be reported during the 2-min walk test (2MWT) test in persons with lower-limb amputations (LLA). The purpose of this study was to determine step counts and oxygen consumption during the 2MWT in LLA. Thirty-five men and women walked for two minutes as quickly as possible while wearing activity monitors (ActiGraph Link on the wrist (LW) and ankle (LA), Garmin vivofit®3 on the wrist (VW) and ankle (VA), and a modus StepWatch on the ankle (SA), and a portable oxygen analyzer. The StepWatch on the ankle (SA) and the vivofit3 on the wrist (VW) had the least error and best accuracy of the activity monitors studied. While there were no significant differences in distance walked, oxygen consumption (VO2) or heart rate (HR) between sexes or level of amputation (p > 0.05), females took significantly more steps than males (p = 0.034), and those with unilateral transfemoral amputations took significantly fewer steps than those with unilateral transtibial amputations (p = 0.023). The VW and SA provided the most accurate step counts among the activity monitors and were not significantly different than hand counts. Oxygen consumption for all participants during the 2MWT was 8.9 ± 2.9 mL/kg/min, which is lower than moderate-intensity activity. While some may argue that steady-state activity has not yet been reached in the 2MWT, it may also be possible participants are not walking as fast as they can, thereby misclassifying their performance to a lower standard.
The New Trend of State Estimation: From Model-Driven to Hybrid-Driven Methods
Authors: Jin Xue-Bo , Robert Jeremiah Ruben Jonhson , Su Ting-Li , Bai Yu-Ting , Kong Jian-Lei
Published: March 2021

State estimation is widely used in various automated systems, including IoT systems, unmanned systems, robots, etc. In traditional state estimation, measurement data are instantaneous and processed in real time. With modern systems’ development, sensors can obtain more and more signals and store them. Therefore, how to use these measurement big data to improve the performance of state estimation has become a hot research issue in this field. This paper reviews the development of state estimation and future development trends. First, we review the model-based state estimation methods, including the Kalman filter, such as the extended Kalman filter (EKF), unscented Kalman filter (UKF), cubature Kalman filter (CKF), etc. Particle filters and Gaussian mixture filters that can handle mixed Gaussian noise are discussed, too. These methods have high requirements for models, while it is not easy to obtain accurate system models in practice. The emergence of robust filters, the interacting multiple model (IMM), and adaptive filters are also mentioned here. Secondly, the current research status of data-driven state estimation methods is introduced based on network learning. Finally, the main research results for hybrid filters obtained in recent years are summarized and discussed, which combine model-based methods and data-driven methods. This paper is based on state estimation research results and provides a more detailed overview of model-driven, data-driven, and hybrid-driven approaches. The main algorithm of each method is provided so that beginners can have a clearer understanding. Additionally, it discusses the future development trends for researchers in state estimation.
Robust LCEKF for Mismatched Nonlinear Systems with Non-Additive Noise/Inputs and Its Application to Robust Vehicle Navigation
Authors: Ben Abdallah Rayen , Vilà-Valls Jordi , Pagès Gaël , Vivet Damien , Chaumette Eric
Published: March 2021

It is well known that the standard state estimation technique performance is particularly sensitive to perfect system knowledge, where the underlying assumptions are: (i) Process and measurement functions and parameters are known, (ii) inputs are known, and (iii) noise statistics are known. These are rather strong assumptions in real-life applications; therefore, a robust filtering solution must be designed to cope with model misspecifications. A possible way to design robust filters is to exploit linear constraints (LCs) within the filter formulation. In this contribution we further explore the use of LCs, derive a linearly constrained extended Kalman filter (LCEKF) for systems affected by non-additive noise and system inputs, and discuss its use for model mismatch mitigation. Numerical results for a robust tracking and navigation problem are provided to show the performance improvement of the proposed LCEKF, with respect to state-of-the-art techniques, that is, a benchmark EKF without mismatch and a misspecified EKF not accounting for the mismatch.
Overground Robot-Assisted Gait Training for Pediatric Cerebral Palsy
Authors: Kim Seung Ki , Park Dongho , Yoo Beomki , Shim Dain , Choi Joong-On , Choi Tae Young , Park Eun Sook
Published: March 2021

The untethered exoskeletal robot provides patients with the freest and realistic walking experience by assisting them based on their intended movement. However, few previous studies have reported the effect of robot-assisted gait training (RAGT) using wearable exoskeleton in children with cerebral palsy (CP). This pilot study evaluated the effect of overground RAGT using an untethered torque-assisted exoskeletal wearable robot for children with CP. Three children with bilateral spastic CP were recruited. The robot generates assistive torques according to gait phases automatically detected by force sensors: flexion torque during the swing phase and extension torque during the stance phase at hip and knee joints. The overground RAGT was conducted for 17~20 sessions (60 min per session) in each child. The evaluation was performed without wearing a robot before and after the training to measure (1) the motor functions using the gross motor function measure and the pediatric balance scale and (2) the gait performance using instrumented gait analysis, the 6-min walk test, and oxygen consumption measurement. All three participants showed improvement in gross motor function measure after training. Spatiotemporal parameters of gait analysis improved in participant P1 (9-year-old girl, GMFCS II) and participant P2 (13-year-old boy, GMFCS III). In addition, they walked faster and farther with lower oxygen consumption during the 6-min walk test after the training. Although participant P3 (16-year-old girl, GMFCS IV) needed the continuous help of a therapist for stepping at baseline, she was able to walk with the platform walker independently after the training. Overground RAGT using a torque-assisted exoskeletal wearable robot seems to be promising for improving gross motor function, walking speed, gait endurance, and gait efficiency in children with CP. In addition, it was safe and feasible even for children with severe motor impairment (GMFCS IV).
Application of WGM Resonances to the Measurement of the Temperature Increment of Ho and Ho-Yb Doped Optical Fibers Pumped at 1125 and 975 nm
Authors: Roselló-Mechó Xavier , Delgado-Pinar Martina , Barmenkov Yuri O. , Kir’yanov Alexander V. , Andrés Miguel V.
Published: March 2021

Optical fiber characterization using whispering gallery mode resonances of the fiber itself has been demonstrated to be a powerful technique. In this work, we exploit the thermal sensitivity of whispering gallery mode resonances to characterize the pump-induced temperature increment in holmium doped and holmium-ytterbium codoped optical fibers. The technique relies on the measurement of the resonances’ wavelength shift due to temperature variation as a function of the pump power. Holmium doped fibers were pumped to the second excited level 5I6 of the Ho3+ ion using a laser diode at 1125 nm and ytterbium-holmium codoped fibers to the 2F5/2 level of the Yb3+ ion by a laser diode at 975 nm. Our results demonstrate that pumping ytterbium-holmium codoped fibers at 975 nm results in dramatic thermal effects, producing a temperature increment two orders higher than that observed in holmium doped fibers pumped with a 1125 nm laser diode.
Characterizing the Performance of a Compact BTEX GC-PID for Near-Real Time Analysis and Field Deployment
Authors: Frausto-Vicencio Isis , Moreno Alondra , Goldsmith Hugh , Hsu Ying-Kuang , Hopkins Francesca M.
Published: March 2021

In this study, we test the performance of a compact gas chromatograph with photoionization detector (GC-PID) and optimize the configuration to detect ambient (sub-ppb) levels of benzene, toluene, ethylbenzene, and xylene isomers (BTEX). The GC-PID system was designed to serve as a relatively inexpensive (~10 k USD) and field-deployable air toxic screening tool alternative to conventional benchtop GCs. The instrument uses ambient air as a carrier gas and consists of a Tenax-GR sorbent-based preconcentrator, a gas sample valve, two capillary columns, and a photoionization detector (PID) with a small footprint and low power requirement. The performance of the GC-PID has been evaluated in terms of system linearity and sensitivity in field conditions. The BTEX-GC system demonstrated the capacity to detect BTEX at levels as high as 500 ppb with a linear calibration range of 0–100 ppb. A detection limit lower than 1 ppb was found for all BTEX compounds with a sampling volume of 1 L. No significant drift in the instrument was observed. A time-varying calibration technique was established that requires minimal equipment for field operations and optimizes the sampling procedure for field measurements. With an analysis time of less than 15 min, the compact GC-PID is ideal for field deployment of background and polluted atmospheres for near-real time measurements of BTEX. The results highlight the application of the compact and easily deployable GC-PID for community monitoring and screening of air toxics.
Cyclic Voltammetry in Biological Samples: A Systematic Review of Methods and Techniques Applicable to Clinical Settings
Authors: Wang Hsiang-Wei , Bringans Cameron , Hickey Anthony J. R. , Windsor John A. , Kilmartin Paul A. , Phillips Anthony R. J.
Published: March 2021

Oxidative stress plays a pivotal role in the pathogenesis of many diseases, but there is no accurate measurement of oxidative stress or antioxidants that has utility in the clinical setting. Cyclic Voltammetry is an electrochemical technique that has been widely used for analyzing redox status in industrial and research settings. It has also recently been applied to assess the antioxidant status of in vivo biological samples. This systematic review identified 38 studies that used cyclic voltammetry to determine the change in antioxidant status in humans and animals. It focusses on the methods for sample preparation, processing and storage, experimental setup and techniques used to identify the antioxidants responsible for the voltammetric peaks. The aim is to provide key information to those intending to use cyclic voltammetry to measure antioxidants in biological samples in a clinical setting.
Recognizing New Trends in Brain Drain Studies in the Framework of Global Sustainability
Authors: Vega-Muñoz Alejandro , Gónzalez-Gómez-del-Miño Paloma , Espinosa-Cristia Juan Felipe
Published: March 2021

Scholars had been documenting the Brain Drain phenomenon producing scientific literature for more than 50 years. After three decades of slow but steady progress, literature about this concept has accelerated its progress and growth path, in line with the 9th sustainable development goal “Build resilient infrastructure, promote sustainable industrialization and foster innovation” Thus, the present article aims to define the current theoretical trends about the analysis of advanced intellectual human capital’s international migratory phenomenon. This study uses a scientometric methodology on a corpus of 1212 articles indexed to the JCR-WoS from Social Sciences. The period covered in the study is from 1965 to 2020. The paper looks to understand how researchers studied the brain drain concept over the last 55 years in various disciplines. The report covers 99 categories from the Journal Citation Report (JCR) index. Results show that there is a scientific research critical mass that is studying the brain drain phenomenon. The analysis shows thematic trends at the sources, discourses, and consolidates classic works and some novel authors. Those new scholars and theoretical trends lead to refocused analysis beyond countries with a high development level. Such movement constitutes a new challenge in this line of research toward studying the effects of the brain drain in the peripheral areas of knowledge production.
The Role of CEO Power on CSR Reporting: The Moderating Effect of Linking CEO Compensation to Shareholder Return
Authors: Pucheta-Martínez María Consuelo , Gallego-Álvarez Isabel
Published: March 2021

The aim of this research was to provide further evidence of the impact of the power of the Chief Executive Officer (CEO) on corporate social responsibility (CSR) disclosure. Additionally, we explore the moderating role of CEO compensation linked to shareholder return on the association between CEO power and CSR disclosure. The theories used follow agency theory and stakeholder theory and the sample comprised 9182 international firm-year observations collected from the Thomson Reuters database from 2009 to 2018. Our model was estimated using the generalized method of moments (GMM) estimator. The results found that CEO power was positively associated with CSR disclosure, contrary to our expectations. Additionally, our evidence also shows that CEO compensation linked to shareholder return plays a positive moderating role on the relationship between CEO power and CSR reporting.
Electric Vehicles in Jordan: Challenges and Limitations
Authors: Shalalfeh Laith , AlShalalfeh Ashraf , Alkaradsheh Khaled , Alhamarneh Mahmoud , Bashaireh Ahmad
Published: March 2021

An increasing number of electric vehicles (EVs) are replacing gasoline vehicles in the automobile market due to the economic and environmental benefits. The high penetration of EVs is one of the main challenges in the future smart grid. As a result of EV charging, an excessive overloading is expected in different elements of the power system, especially at the distribution level. In this paper, we evaluate the impact of EVs on the distribution system under three loading conditions (light, intermediate, and full). For each case, we estimate the maximum number of EVs that can be charged simultaneously before reaching different system limitations, including the undervoltage, overcurrent, and transformer capacity limit. Finally, we use the 19-node distribution system to study these limitations under different loading conditions. The 19-node system is one of the typical distribution systems in Jordan. Our work estimates the upper limit of the possible EV penetration before reaching the system stability margins.
Analysis of the Behavior of Abstractions in Two Urban Micro-Basins of the City of Cuenca (Ecuador), through an Aggregate Model
Authors: Rubio-Ramírez Ricardo , Jerves-Cobo Rubén , Mora-Serrano Diego
Published: March 2021

Several cities in developing countries are challenging the permanent process of urbanization. This generates a great disturbance on the hydrological response of the urbanized area during rainfall events, which can cause floods. Among the disturbances that urbanized basins may suffer, it is found that variations in rain losses (hydrological abstractions) can be estimated by the named volumetric runoff coefficient (CVOL) methodology. In the present study, this methodology is used in an attempt to estimate the hydrological abstraction of two nearby urbanized basins, with different degrees of impermeability, located in the city of Cuenca in Ecuador. The data for that analysis were collected between April and May of 2017. The results obtained indicate that the micro-basin with the largest impervious area presents the higher initial hydrological losses, the higher rate of decrease in abstractions, and the higher stormwater runoff flows per unit area. In addition, the abstractions found in the two urban micro-basins show great sensitivity to the maximum rainfall intensity and do not relate to the antecedent soil moisture. These results demonstrate the importance of having higher pervious surfaces in urbanized areas because they lead to reduce negative impacts associated with increased stormwater runoff on impervious surfaces.
Subjective Well-Being as a Potential Policy Indicator in the Context of Urbanization and Forest Restoration
Authors: Takahashi Takuya , Uchida Yukiko , Ishibashi Hiroyuki , Okuda Noboru
Published: March 2021

The enhancement of human well-being is one of the ultimate goals of resource management; however, it is not explicitly considered by forest policy indicators. Our previous studies examined how Japanese citizens in the Yasu River watershed of the Shiga Prefecture perceived subjective well-being related to forests (forest SWB). We found a negative correlation between forest SWB and forest ownership, suggesting dissatisfaction with the low profitability of forest ownership. Based on this result, in this paper, we argue that forest SWB can be an important indicator for policymaking in the context of urbanization and forest restoration and can complement existing forest indicators focusing mainly on physical and objective properties. First, we propose that a direct measurement of well-being (e.g., forest SWB) is preferable over an indirect measurement (e.g., GDP), for policymaking processes related to forests. Second, forest SWB can reflect the quality of our interactions with forests, which is important in urbanized societies which tend to have reduced experiences with nature. Third, forest SWB could identify inequalities between the users of forest ecosystem services and forest managers. Overall, forest SWB can be a holistic indicator to capture a variety of perspectives held by citizens.
Research of the Behavior of Clay Materials with Double Porosity
Authors: Lahuta Hynek , Pais Luis
Published: March 2021

This contribution presents results from a series of compression and undrained triaxial tests to study the mechanical behavior of dump clay from the north of Bohemia. The use of these materials as a foundation for construction can’t be achieved without the adoption of some precautions. This comes from embankment, formed by digging the ground (altered claystone), up to the level of coal mining which is in a sub horizontal stratigraphic layer. A potential static liquefaction behavior was observed in undrained tests for high confinement stress. A structural collapse was noticed with the results obtained in the triaxial test. This collapse is characterized by an unexpected large decrease in deviator and mean effective stress. The soils formed have strength properties that are potentially dangerous. These concepts can improve the use of these kinds of soils in geotechnical engineering work. It continues and expands the results obtained in previous research, especially the future problematic use of these materials as the foundation soil for line or building structures.
An Evaluation of the Three Pillars of Sustainability in Cities with High Airbnb Presence: A Case Study of the City of Madrid
Authors: Álvarez-Herranz Agustín , Macedo-Ruíz Edith
Published: March 2021

The recent proliferation of private tourist accommodations on what has been known as sharing economy has induced new models on urban tourism and on the use of traditional housing. Urban tourism pressure has caused many transformation processes with important impacts in neighborhoods with high tourist interest, which are shown in the evolution of certain urban sustainability indicators, such as those proposed by the UN-Habitat Agenda for Sustainable Cities in line with the principles of the Leipzig Charter on Sustainable European Cities. Due to the above, the objective of this work is to analyze the spatial distribution of Airbnb accommodations, and explore the factors associated with the situation of Airbnb rentals in relation to the indicators of urban sustainability of neighborhoods and variables related to the gentrification processes of neighborhoods in which there is crowding or overtourism, measured through the Global Tourist Stress Index. For this, a first-order spatial autoregressive panel (SAR) data model with fixed effects has been specified, the results of which provide us with information to understand how sustainability indicators in the neighborhoods of the city of Madrid in the time period 2015–2018, they would explain the location and number of Airbnb accommodations found there. Additionally, it allows us to observe the existence of a spillover effect from the central neighborhoods, with a high per capita income, to nearby neighborhoods with lower income due to the level of tourist crowding, which is a contribution to the scarce existing literature.
Beyond Sustainable Intensification: Transitioning Primary Sectors through Reconfiguring Land-Use
Authors: Bayne Karen , Renwick Alan
Published: March 2021

Internationally there is a desire to transition farming systems towards more sustainable production in response to global and local social and environmental challenges. This transition has often been linked with a movement towards ‘sustainable intensification’ which, although having advantages, has raised questions about a lack of attention to, for example, social and ethical consideration of food and fibre production. Whilst there is general consensus that a transition is required, what is much less clear is what transitioned agricultural sectors would look like in terms of land-use configurations and how such a change can be achieved. Using New Zealand as an example, this paper provides some initial views on what such a reconfiguration may entail. The paper identifies and assesses a range of possible alternative land use configurations that, in general, lead to landscape/regional diversification. The importance of incorporating new high value low intensity (niche) systems into the landscape is highlighted. Development of these niches to achieve scale is shown to be key to the transition process. The joint role of the private (through markets) and public (through policy) sectors in driving the transition is highlighted.
Policy-Oriented Learning: A Case on Initiating Long-Term Care Insurance in China’s Social Security Sector
Authors: Zhang Jian , Yu Xiao , Zhang Yanzhe
Published: March 2021

This paper explores the initiation process of the long-term care insurance (LTCI) policy in China’s social security sector, and focuses on policy-oriented learning activities to develop initiatives from German lessons. It presents a case from the LTCI pilot program, which serves as a new policy product that provides care to the elderly and disabled and upgrades the social security sector’s performance. This study implements policy-oriented learning to construct an analytical framework and applies it to China’s social security system. This research suggests that policy-oriented learning is a rational tool used to manufacture policy products that enable intellectual development and can provide roadmaps for administrative reform. The findings contribute to the current knowledge on policy-oriented learning by offering new insights from China’s experience with LTCI, thus helping to fill the gaps that are created when policy-oriented learning is applied to different systems and contexts, with unique cultural, traditional, and political characteristics.
A European Assessment of the Solar Energy Cost: Key Factors and Optimal Technology
Authors: Lugo-Laguna Daniel , Arcos-Vargas Angel , Nuñez-Hernandez Fernando
Published: March 2021

Solar energy has become one of the most important sources of energy all around the world. Only in the European Union, between 2010 and 2019, solar photovoltaic (PV) electricity generation capacity increased from 1.9 to over 133 GW. Throughout this work, an economic analysis of the production of photovoltaic solar energy utility scale facilities is performed, previously defining some theoretical concepts relating to electricity generation by means of photovoltaic modules, as well as commenting on studies that have inspired the project. In order to carry out this economic analysis, the locations of twenty capital cities within European Union countries are selected, in order to estimate their yearly solar PV energy produced under specific conditions. The Levelized Costs of Energy (LCOE) is calculated with the goal of comparing the profitability of each photovoltaic tracking technology: fixed, one-axis tracking systems (vertical or inclined) and two-axis tracking systems; including LCOE maps country-wise for each technology. A sensitivity analysis is also presented, in order to evaluate the significance and impact of the main variables involved in the analysis. The results show that one-axis tracking systems are the best option in all countries, reducing LCOE by more than 20% when compared to two-axis tracking system. The impact of wages is also significant. In higher latitudes, in most cases, wages also increase, hence the LCOE is higher and consequently less interesting for a potential investor.
Bringing the User Back in the Building: An Analysis of ESG in Real Estate and a Behavioral Framework to Guide Future Research
Authors: Kempeneer Shirley , Peeters Michaël , Compernolle Tine
Published: March 2021

Investors are currently obliged to take environment, social, and governance (ESG) issues into consideration as part of their fiduciary duty. As such, it becomes increasingly important to identify sustainable investments that also hold financial value. A sector where this is especially underdeveloped is real estate. This has a lot to do with the obfuscated conceptualization of ESG. The article identifies key gaps in the literature and practice and provides a framework to further the understanding of how ESG factors can add societal and financial value in the real estate sector. A key premise of the article is that the user in the building is grossly overlooked. Drawing on insights from behavioral social science and environmental psychology, the paper explains the role of the user in improving buildings’ ESG, also taking into account the investment value. To conclude, the article makes the case that the transition to user-centered smart real estate is the solution to improving both the environmental (E) and social (S) sustainability of buildings, as well as their investment value. Therefore, practitioners and academics are encouraged to critically evaluate and contextualize the ESG framework they are using as well as the extent to which users are considered and smart technology is employed.
Biochar and Arbuscular Mycorrhizal Fungi Play Different Roles in Enabling Maize to Uptake Phosphorus
Authors: Li Mengying , Cai Liqun
Published: March 2021

The addition of biochar alters soil habitats and has an active effect on the symbiotic relationship between plants and mycorrhizal fungi. However, it is still unclear whether this effect alters the strategy of phosphorus uptake by plants. Therefore, pot experiments were conducted in order to investigate the effects of mycorrhizal colonization and biochar addition on plant growth, phosphorus absorption, and rhizosphere Olsen-P supply in maize under two moisture conditions—60% field water capacity (FWC) and 40% FWC. It was found that the addition of biochar increased the colonization rate of arbuscular mycorrhizal fungi (AMF), and all the addition treatments significantly improved maize biomass, peroxidase (POD) activity, chlorophyll content, photosynthetic rate (Pn), plant height, leaf area, shoot phosphorus content, and phosphorus uptake by maize under the two moisture conditions. In addition, biochar had significant effects on root morphology under both water conditions, whereas AMF only showed significant effects under water stress. In contrast, phosphatase activity and microbial activity were higher in the AMF inoculation treatment than in the biochar addition treatment, and the trend was more significant under water stress. Principal component analysis (PCA) showed that root morphology, rhizosphere microbial activity, phosphatase activity, available phosphorus content, and shoot phosphorus content had significant positive correlations. It was concluded that biochar aids plant uptake of phosphorus mainly by regulating root morphology and plant phosphorus content, whereas the large mycelium of AMF enhances microbial activity and phosphatase activity, thereby enabling more efficient phosphorus uptake by maize, especially under conditions of water stress.
Rethinking Sustainable Community-Based Tourism: A Villager’s Point of View and Case Study in Pampang Village, Indonesia
Authors: Priatmoko Setiawan , Kabil Moaaz , Purwoko Yitno , Dávid Lóránt Dénes
Published: March 2021

Community-based tourism (CBT) considers one sustainable form of tourism to enhance tourists’ and local communities’ relationships. By investigating and studying the previous scientific production of the CBT field in general and, in particular, rural CBT, the researchers found that the local communities’ roles in shaping this type of tourism have been given great importance. This literature mainly focuses on rural CBT from the academic researcher’s perspective. This study aimed to understand the villager’s view on rural sustainable CBT in Pampang Village, Indonesia. In our research, we used the triangulation method based on three kinds of data: in-depth structured interviews, non-participant field observations, and quantitative sustainability aspects of the local attractions. The research results helped us design a model for the formation of sustainable rural CBT activities in Indonesia, which depends on formal and informal leader figures in the community instead of only the community’s solidarity, as much previous research has indicated.
Spatial Analysis of the Drivers, Characteristics, and Effects of Forest Fragmentation
Authors: Slattery Zoe , Fenner Richard
Published: March 2021

Building on the existing literature, this study examines whether specific drivers of forest fragmentation cause particular fragmentation characteristics, and how these characteristics can be linked to their effects on forest-dwelling species. This research uses Landsat remote imaging to examine the changing patterns of forests. It focuses on areas which have undergone a high level of a specific fragmentation driver, in particular either agricultural expansion or commodity-driven deforestation. Seven municipalities in the states of Rondônia and Mato Grosso in Brazil are selected as case study areas, as these states experienced a high level of commodity-driven deforestation and agricultural expansion respectively. Land cover maps of each municipality are created using the Geographical Information System software ArcGIS Spatial Analyst extension. The resulting categorical maps are input into Fragstats fragmentation software to calculate quantifiable fragmentation metrics for each municipality. To determine the effects that these characteristics are likely to cause, this study uses a literature review to determine how species traits affect their responses to forest fragmentation. Results indicate that, in areas that underwent agricultural expansion, the remaining forest patches became more complex in shape with longer edges and lost a large amount of core area. This negatively affects species which are either highly dispersive or specialist to core forest habitat. In areas that underwent commodity-driven deforestation, it was more likely that forest patches would become less aggregated and create disjunct core areas. This negatively affects smaller, sedentary animals which do not naturally travel long distances. This study is significant in that it links individual fragmentation drivers to their landscape characteristics, and in turn uses these to predict effects on species with particular traits. This information will prove useful for forest managers, particularly in the case study municipalities examined in this study, in deciding which species require further protection measures. The methodology could be applied to other drivers of forest fragmentation such as forest fires.
Cultural Sustainability: Teaching and Design Strategies for Incorporating Service Design in Religious Heritage Branding
Authors: Chang Tsen-Yao , Chuang Yu-Ju
Published: March 2021

Under globalization, a local brand must be managed by strengthening local uniqueness and representativeness to become a unique brand that is irreplaceable in the international market. An examination of Taiwan’s cultural characteristics and resources shows that religion has been the focus of the government’s tourism promotion in recent years. A religious site is filled with architectural, historical, aesthetic, and cultural elements. Through online marketing and multilingual introductions, the government has packaged Taiwan’s religious culture into a brand. Temples not only provide devotees with a place for spiritual sustenance but also offer them cultural tourism experiences. When service design is integrated into the branding process, the various touchpoints experienced are the key to promoting temple and tourist interactions. A culture can be converted into unique and representative patterns by using brand design strategies, thereby creating opportunities for cultural sustainability. This study chose a national monument temple in Yunlin County, Taiwan, as the study location. Through a course of instruction, students with professional design backgrounds were granted the opportunity to work in a monumental temple, where they practiced participatory learning, played the role of mentors, and developed design proposals. By using observation and interview methods as well as service design tools, the students identified problems and needs and proposed service design insights and design implementation plans. The results of this study were analyzed along with the design flow, course outcomes, and students’ open-ended questionnaires. Finally, a religious branding design strategy based on the core value of cultural sustainability was proposed.
Mechanochemical Treatment of Historical Tungsten Tailings: Leaching While Grinding for Tungsten Extraction Using NaOH
Authors: Mulenshi Jane , Chelgani Saeed Chehreh , Rosenkranz Jan
Published: March 2021

Innovative tungsten (W) extraction techniques are continually being sought because of challenges of low leaching efficiencies, despite using advanced processing units such as autoclaves operating high temperatures and pressures. Compared to conventional leaching, mechanochemical treatment improves the efficiency of leaching. Therefore, in this study, an innovative mechanochemical treatment method, referred to as leaching while grinding (LWG), was employed as a reprocessing option to optimize W recovery from historical tungsten tailings. Experiments were run using the regular two-level factorial design to screen through the four factors of stirrer speed, liquid/solid ratio, temperature, and digestion time to assess their criticality and effects in the LWG process. The stirrer speed and the liquid/solid ratio were the most critical factors in the optimization of W recovery. The maximum W recovery (91.2%) was attained at the highest stirrer speed (410 rpm), low liquid/solid ratio (0.8), long digestion time (6 h), and low leaching temperature (60 °C). The attained low leaching temperature (60 °C) was due to the mechanical activation of scheelite resulting from the simultaneous grinding and leaching. For such low- grade W material, liquid/solid ratio optimizing is critical for maintaining the digestion mixture fluidity, and for environmental and economic sustainability regarding the sodium hydroxide (NaOH) consumption, which was low.
Identifying Hotspots of Overgrazing in Pastoral Areas: Livestock Mobility and Fodder Supply–Demand Balances in Nyangatom, Lower Omo Valley, Ethiopia
Authors: Gebeyehu Adane Kebede , Sonneveld Ben G. J. S. , Snelder Denyse J.
Published: March 2021

The Nyangatom, in South Omo, Ethiopia, are a group of agro-pastoralists whose access to land is affected by large-scale sugarcane development projects. An informed selection of appropriate livestock management measures by local communities requires a spatially explicit representation of prevailing and changing supply–demand relationships for livestock herds among the Nyangatom. This study addresses this caveat and identifies seasonal and location-specific ‘hotspots’ in Nyangatom, where fodder demand exceeds supply. Assessments of fodder production are based on primary data collected through focus group discussions, key informant interviews, and field observations. Overall, annual fodder availability is estimated at 508,967 tonnes against the requirement of 584,205 tons, resulting in a deficit of 12.9% annually after out-migration. Under the implementation of the Omo-V sugarcane project and climate change, the fodder supply deficit will worsen to 219,977 tonnes annually. The most critical dry matter hotspots are found in the western and central parts of Nyangatom near the Kibish River, which shows the highest livestock density. In contrast, better fodder supply is estimated around the southwestern and northeastern parts. Change in policy, the frequency of droughts, conflict, and the large-scale irrigation schemes-induced reduction of the Omo River floods are accounted for the changes. Thus, there are strong signals to the local community and government to collaborate to reduce the potential constraints that affect sustainable rangeland management and food security and ensure sufficient attention to the interest of the agro-pastoralists.
Analysis of the Competitiveness of the Performance of Baltic Ports in the Context of Economic Sustainability
Authors: Gaidelys Vaidas , Benetyte Raminta
Published: March 2021

Baltic Seaports are a part of the sustainable global transport infrastructure. The main competitors of the Baltic countries in Baltic Sea region are the ports of Lithuania, Latvia, and Estonia. The ports of all three Baltic States are important transit corridors, connecting not only East and West, but also South and North. Periodical investments, modernization, and the construction of new terminals allow the Port of Klaipeda to successfully compete with neighbouring ports and strive for leadership positions. Thus, the aim of our study is to investigate the competitive environment of the Baltic Sea region. We use systematization, grouping, summarization of the scientific literature, data collection, comparison, financial analysis, and capacity calculation. The main results show that the Port of Klaipeda, a seaport on the eastern Baltic coast, is an important hub of the East-West (IXB) transport corridor, connecting roads and sea routes in this direction. With the accession of new members, including Lithuania, to the EU in 2004, the Baltic Sea became the internal Sea of the Union. Many Baltic seaports belong to the same system and organizations (ESPO, BPO). EU ports policy provides them with equal requirements for security, transport regulation, environmental protection, anti-air pollution, and sustainable development. The results obtained enable exploration perspectives. This includes a feasibility study for port development and attracting new investment from foreign capital markets in the Baltic Sea region.
Economic Transition and the Evolution of City-Size Distribution of China’s Urban System
Authors: Wang Jiejing , Chen Yanguang
Published: March 2021

The evolution of city size distribution in China has gained a great deal of scholarly attention. However, little is known about the effect of economic transition on the reorganization of city size distribution in China. Using an urban hierarchy with cascade structure model, we decompose Zipf’s law into two exponential functions that provide a new way of examining the dynamic processes of urban system evolution. This study aims to investigate the dominating latent forces that affect China’s city size distribution through mathematical modeling of the hierarchical scaling laws based on census data of 1982, 1990, 2000, and 2010. A number of features of China’s city size distribution are found. First, the size distribution of Chinese cities displayed a clear trend of evolving toward the Zipf distribution, which is the result of economic transition from planned to market. Second, the rank-size pattern still deviates slightly from the standard Zipf distribution, as indicated by the narrow scaling range and departure of the scaling exponent from the theoretically expected value. We argue that the top-down state regulation is a critical cause of deviation of China’s city size distribution from Zipf’s law.
Optimization of the Opening Shape in Slot Spray Nozzles in a Field Boom Sprayer
Authors: Wawrzosek Jacek , Parafiniuk Stanisław
Published: March 2021

The European Standard ISO 16122-2:2015 requires that the coefficient of variation for sprayed liquid fall should not exceed 10%. Field sprayers generate a stream of liquid sprayed at an angle that depends on the design of the nozzles. Among field boom sprayers, previous methods for selecting the shape of the opening of a single-slotted spray nozzle have been based on the following rectangular, triangular, normal, beta, and truncated normal distributions; distribution obtained from a nozzle with a stream in the form of an empty cone; and glued square functions. These methods, however, have provided a limited range of uniformity. Consequently, the initial assumption that the monotonicity of the function corresponds to the shape of a quarter of the symmetrical oval nozzle opening allows for a full computerized optimization of nozzle shape with a spray angle of α = 110° (or α = 120°). In this case, the spray uniformity parameter is controlled and freely declines almost to zero. In this study, based on the nonlinear shape obtained, we developed the shape of the nozzle outlet opening with a coefficient of variation of 0.388% using spline linear functions. Further applications of the symmetry of the developed model would allow for multiple modifications of the shape of this opening, and therefore, without changing the spray uniformity parameter, nozzles with slightly different characteristics could be obtained.
The Implementation of the Smart City Process—Researchers’ Knowledge in Detecting Transport System Defects
Authors: Dostál Roman , Kocourek Josef , Matysková Aneta , Moudrá Karolína , Nižňanský Vojtěch
Published: March 2021

Although the Republic of Moldova has experienced massive increase in vehicle ownership and use, some of the latest advances in how to approach and nurture public space are underutilized. This article summarizes the basic findings of a project aimed at transfer of knowledge and the implementation of the smart city process in Chișinău, Moldova. Chișinău presents a perfect opportunity for full-scale transformation regarding mobility in the smart city process. In its current state, where there are still enough opportunities to make significant improvements and for the region itself, the Republic of Moldova falls into the category of middle- to lower-income countries. Moreover, this article looks at the difficulties of preparing a smart mobility strategy while under the effect of the current COVID-19 pandemic in the form of social distancing by the city. The subject of study is to determine whether a long-distance strategy can be properly created and introduced, mostly based on proper communication. Key data sources were examined and chosen as the basis for determining weaknesses and as a basis for determining the main pillars. While challenging, this paper finds distanced knowledge transfer and planning to be achievable.
An Efficient Approach for Sidelobe Level Reduction Based on Recursive Sequential Damping
Authors: Albagory Yasser , Alraddady Fahad
Published: March 2021

Recently, antenna array radiation pattern synthesis and adaptation has become an essential requirement for most wireless communication systems. Therefore, this paper proposes a new recursive sidelobe level (SLL) reduction algorithm using a sidelobe sequential damping (SSD) approach based on pattern subtraction, where the sidelobes are sequentially reduced to the optimum required levels with near-symmetrical distribution. The proposed SSD algorithm is demonstrated, and its performance is analyzed, including SLL reduction and convergence behavior, mainlobe scanning, processing speed, and performance under mutual coupling effects for uniform linear and planar arrays. In addition, the SSD performance is compared with both conventional tapering windows and optimization techniques, where the simulation results show that the proposed SSD approach has superior maximum and average SLL performances and lower processing speeds. In addition, the SSD is found to have a constant SLL convergence profile that is independent on the array size, working effectively on any uniform array geometry with interelement spacing less than one wavelength, and deep SLL levels of less than −70 dB can be achieved relative to the mainlobe level, especially for symmetrical arrays.