bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced Performance of a Cascaded Receiver Consisting of a DNN-Based Waveform-to-Symbol Converter and Modified NN-Based DD-LMS in CAP Underwater VLC System
Authors: Lin Xianhao , Hu Fangchen , Chi Nan
Published: January 2023

Underwater visible light communication (UVLC) based on LEDs has become a competitive candidate, which is able to provide high data rates, low latency and low cost for next-generation wireless communication technologies. However, it is still challenging to achieve high-speed communication because of bottleneck problems such as bandwidth limitation and linear and nonlinear distortions. Traditional Deep-learning Neural Network (DNN)-based waveform-to-symbol converter is verified to be an effective method to alleviate them, but impractical due to high complexity. To achieve a better tradeoff between communication performance and computation complexity, a cascaded receiver consisting of a DNN-based waveform-to-symbol converter and modified Neural Network (NN)-based decision-directed least mean square (DD-LMS) is then innovatively proposed. With fewer taps and nodes than the traditional converter, the front-stage converter could mitigate the majority of Inter-Symbol Interference (ISI) and signal nonlinear distortions. Then modified NN-based DD-LMS is cascaded to improve communication performance by reducing phase offset, making received constellation points more concentrated and closer to standard constellation points. Compared with the traditional converter, the cascaded receiver could achieve 89.6% of signal Vpp dynamic range with 12.4% of complexity in the 64APSK UVLC system. Moreover, the ratio of signal Vpp dynamic range and total trainable parameters is 1.24 × 10−1 mV, while that of the traditional converter is 1.95 × 10−2 mV. The cascaded receiver used in 64APSK UVLC systems is experimentally verified to achieve enhanced performance, thus as a promising scheme for future high-speed underwater VLC.
Response of Pea Plants (Pisum sativum cv. Ran 1) to NaCl Treatment in Regard to Membrane Stability and Photosynthetic Activity
Authors: Popova Antoaneta V. , Borisova Preslava , Vasilev Dimitar
Published: January 2023

Salinity is one of the most extreme abiotic stress factors that negatively affect the development and productivity of plants. The salt-induced injuries depend on the salt tolerance of the plant species, salt concentration, time of exposure and developmental stage. Here, we report on the response of pea plants (Pisum sativum L. cv Ran 1) to exposure to increasing salt concentrations (100, 150 and 200 mM NaCl) for a short time period (5 days) and the ability of the plants to recover after the removal of salt. The water content, membrane integrity, lipid peroxidation, pigment content and net photosynthetic rate were determined for the pea leaves of the control, treated and recovered plants. Salt-induced alterations in the primary photosynthetic reactions and energy transfer between the main pigment–protein complexes in isolated thylakoid membranes were evaluated. The pea plants were able to recover from the treatment with 100 mM NaCl, while at higher concentrations, concentration-dependent water loss, the disturbance of the membrane integrity, lipid peroxidation and an increase in the pigment content were detected. The net photosynthetic rate, electron transport through the reaction centers of PSII and PSII, activity of PSIIα centers and energy transfer between the pigment–protein complexes were negatively affected and were not restored after the removal of NaCl.
Silencing of a Pectin Acetylesterase (PAE) Gene Highly Expressed in Tobacco Pistils Negatively Affects Pollen Tube Growth
Authors: Lubini Greice , Ferreira Pedro Boscariol , Quiapim Andréa Carla , Brito Michael Santos , Cossalter Viviane , Pranchevicius Maria Cristina S. , Goldman Maria Helena S.
Published: January 2023

Successful plant reproduction and fruit formation depend on adequate pollen and pistil development, and pollen–pistil interactions. In Nicotiana tabacum, pollen tubes grow through the intercellular spaces of pistil-specialized tissues, stigmatic secretory zone, and stylar transmitting tissue (STT). These intercellular spaces are supposed to be formed by the modulation of cell wall pectin esterification. Previously we have identified a gene preferentially expressed in pistils encoding a putative pectin acetylesterase (PAE), named NtPAE1. Here, we characterized the NtPAE1 gene and performed genome-wide and phylogenetic analyses of PAEs. We identified 30 PAE sequences in the N. tabacum genome, distributed in four clades. The expression of NtPAE1 was assessed by RT-qPCR and in situ hybridization. We confirmed NtPAE1 preferential expression in stigmas/styles and ovaries and demonstrated its high expression in the STT. Structural predictions and comparisons between NtPAE1 and functional enzymes validated its identity as a PAE. Transgenic plants were produced, overexpressing and silencing the NtPAE1 gene. Overexpressed plants displayed smaller flowers while silencing plants exhibited collapsed pollen grains, which hardly germinate. NtPAE1 silencing plants do not produce fruits, due to impaired pollen tube growth in their STTs. Thus, NtPAE1 is an essential enzyme regulating pectin modifications in flowers and, ultimately, in plant reproduction.
Isoprene-Emitting Tobacco Plants Are Less Affected by Moderate Water Deficit under Future Climate Change Scenario and Show Adjustments of Stress-Related Proteins in Actual Climate
Authors: Pollastri Susanna , Velikova Violeta , Castaldini Maurizio , Fineschi Silvia , Ghirardo Andrea , Renaut Jenny , Schnitzler Jörg-Peter , Sergeant Kjell , Winkler Jana Barbro , Zorzan Simone , Loreto Francesco
Published: January 2023

Isoprene-emitting plants are better protected against thermal and oxidative stresses, which is a desirable trait in a climate-changing (drier and warmer) world. Here we compared the ecophysiological performances of transgenic isoprene-emitting and wild-type non-emitting tobacco plants during water stress and after re-watering in actual environmental conditions (400 ppm of CO2 and 28 °C of average daily temperature) and in a future climate scenario (600 ppm of CO2 and 32 °C of average daily temperature). Furthermore, we intended to complement the present knowledge on the mechanisms involved in isoprene-induced resistance to water deficit stress by examining the proteome of transgenic isoprene-emitting and wild-type non-emitting tobacco plants during water stress and after re-watering in actual climate. Isoprene emitters maintained higher photosynthesis and electron transport rates under moderate stress in future climate conditions. However, physiological resistance to water stress in the isoprene-emitting plants was not as marked as expected in actual climate conditions, perhaps because the stress developed rapidly. In actual climate, isoprene emission capacity affected the tobacco proteomic profile, in particular by upregulating proteins associated with stress protection. Our results strengthen the hypothesis that isoprene biosynthesis is related to metabolic changes at the gene and protein levels involved in the activation of general stress defensive mechanisms of plants.
Growing of the Cretan Therapeutic Herb Origanum Dictamnus in The Urban Fabric: The Effect of Substrate and Cultivation Site on Plant Growth and Potential Toxic Element Accumulation
Authors: Martini Aikaterini N. , Papafotiou Maria , Massas Ioannis , Chorianopoulou Nikoleta
Published: January 2023

Origanum dictamnus L. (Lamiaceae) is a perennial herb endemic to the Greek island of Crete, widely used for tea preparation, medicinal purposes, and food flavoring, as well as an ornamental plant. The aim of this work was to introduce the species to the green roof sector while serving urban agriculture. Thus, its growth potential was investigated, along with the content of nutrients (N, P, K, Na) and the accumulation of heavy metals (Cu, Pb, Ni, Mn, Zn, Fe) in its tissues, in two cultivation sites in Athens, Greece, i.e., an extensive green roof and at ground level next to a moderate traffic road. Cultivation took place in plastic containers with a green roof infrastructure fitted, in two substrate types (grape marc compost, perlite, and pumice 3:3:4 v/v, and grape marc compost, perlite, pumice, and soil 3:3:2:2 v/v), with 10 cm depth. Plant growth was favored by the soil substrate, but it was also satisfactory in the soilless one. Cultivation site affected heavy metal accumulation, resulting in higher concentrations both in leaves and in flowers at street level, while no differences were observed in roots. Washing the tissues reduced heavy metal concentrations only in leaves produced at the street level. Substrate type significantly affected Mn concentration in all plant tissues and Fe in roots, with the highest values measured in the soil substrate. Thus, O. dictamnus could be effectively cultivated in sustainable green roofs, better on a soilless substrate to lower construction weight. Careful selection of the cultivation site could minimize contamination with environmental pollutants if human consumption is also desired.
Natural Active Ingredients and TRPV1 Modulation: Focus on Key Chemical Moieties Involved in Ligand–Target Interaction
Authors: Andrei Corina , Zanfirescu Anca , Nițulescu George Mihai , Olaru Octavian Tudorel , Negreș Simona
Published: January 2023

Diseases such as cancer, neurological pathologies and chronic pain represent currently unmet needs. The existing pharmacotherapeutic options available for treating these conditions are limited by lack of efficiency and/or side effects. Transient receptor potential vanilloid 1 ion channel emerged as an attractive therapeutic target for developing new analgesic, anti-cancer and antiepileptic agents. Furthermore, various natural ingredients were shown to have affinity for this receptor. The aim of this narrative review was to summarize the diverse natural scaffolds of TRPV1 modulators based on their agonistic/antagonistic properties and to analyze the structure–activity relationships between the ligands and molecular targets based on the results of the existing molecular docking, mutagenesis and in vitro studies. We present here an exhaustive collection of TRPV1 modulators grouped by relevant chemical features: vanilloids, guaiacols, phenols, alkylbenzenes, monoterpenes, sesquiterpenoids, alkaloids, etc. The information herein is useful for understanding the key structural elements mediating the interaction with TRPV1 and how their structural variation impacts the interaction between the ligand and receptor. We hope this data will contribute to the design of novel effective and safe TRPV1 modulators, to help overcome the lack of effective therapeutic agents against pathologies with high morbidity and mortality.
Quantification of Protein Uptake by Endocytosis in Carnivorous Nepenthales
Authors: Ivesic Caroline , Krammer Stefanie , Koller-Peroutka Marianne , Laarouchi Aicha , Gruber Daniela , Lang Ingeborg , Lichtscheidl Irene K. , Adlassnig Wolfram
Published: January 2023

Carnivorous plants adsorb prey-derived nutrients partly by endocytosis. This study quantifies endocytosis in Drosophyllum lusitanicum, Drosera capensis, Drosera roseana, Dionaea muscipula and Nepenthes × ventrata. Traps were exposed to 1% fluorescent-labeled albumin (FITC-BSA), and uptake was quantified repeatedly for 64 h. Formation of vesicles started after ≤1 h in adhesive traps, but only after 16 h in species with temporary stomach (D. muscipula and N. × ventrata). In general, there are similarities in the observed species, especially in the beginning stages of endocytosis. Nonetheless, further intracellular processing of endocytotic vesicles seems to be widely different between species. Endocytotic vesicle size increased significantly over time in all species except in D. capensis. Fluorescence intensity of the endocytotic vesicles increased in all species except D. muscipula. After 64 h, estimates for FITC-BSA absorption per gland ranged from 5.9 ± 6.3 ng in D. roseana to 47.8 ± 44.3 ng in N. × ventrata, demonstrating that endocytosis substantially contributes to the adsorption of prey-derived nutrients.
Recent Insights into Plant miRNA Biogenesis: Multiple Layers of miRNA Level Regulation
Authors: Bajczyk Mateusz , Jarmolowski Artur , Jozwiak Monika , Pacak Andrzej , Pietrykowska Halina , Sierocka Izabela , Swida-Barteczka Aleksandra , Szewc Lukasz , Szweykowska-Kulinska Zofia
Published: January 2023

MicroRNAs are small RNAs, 20–22 nt long, the main role of which is to downregulate gene expression at the level of mRNAs. MiRNAs are fundamental regulators of plant growth and development in response to internal signals as well as in response to abiotic and biotic factors. Therefore, the deficiency or excess of individual miRNAs is detrimental to particular aspects of a plant’s life. In consequence, the miRNA levels must be appropriately adjusted. To obtain proper expression of each miRNA, their biogenesis is controlled at multiple regulatory layers. Here, we addressed processes discovered to influence miRNA steady-state levels, such as MIR transcription, co-transcriptional pri-miRNA processing (including splicing, polyadenylation, microprocessor assembly and activity) and miRNA-encoded peptides synthesis. MiRNA stability, RISC formation and miRNA export out of the nucleus and out of the plant cell also define the levels of miRNAs in various plant tissues. Moreover, we show the evolutionary conservation of miRNA biogenesis core proteins across the plant kingdom.
Effects of Annealing Temperature and Time on Properties of Thermoplastic Polyurethane Based on Different Soft Segments/Multi-Walled Carbon Nanotube Nanocomposites
Authors: Jirakittidul Kittimon , Limthin Darawan , Mahithithummathorn Sarita , Phaewchimphlee Seenam
Published: January 2023

Typically, polymer chains can move under the annealing process, resulting in an ordered structure arrangement. This causes an improvement in nanocomposite properties and in the dispersion of filler. In this research, annealed thermoplastic polyurethane (PU)/multi-walled carbon nanotube (MWCNT) nanocomposites were studied to investigate the effect of annealing on the selective dispersion of MWCNTs. PU matrices were composed of two different soft segments, i.e., polyether (PU-Ether) and polyester (PU-Ester). Nanocomposites were prepared by the melt mixing process and annealed at 80 to 120 °C for 6 to 24 h. The increases in annealing time and temperature resulted in microphase separation in segmented PU and the orientation of crystalline structures in the segregated hard domain. Nanocomposites showed higher electrical conductivity after annealing. This implies that the movement of PU chains during heat treatment encouraged the development of the MWCNT network. However, the increase in ordered structures could obstruct the MWCNT network, resulting in lower electrical conductivity levels. Considering the selective dispersion of MWCNT in PU matrices, it was found that MWCNTs dispersed in soft segments of PU-Ether, leading to a significant decrease in elongation at the break after annealing. On the other hand, a decrease in elasticity of PU-Ester nanocomposites was not observed as a result of MWCNT dispersal in hard segments.
Study on Experiment and Simulation of Shear Force on Membrane with Dynamic Cross-Flow for Lignin in Black Liquor
Authors: Zhao Wenjie , Wang Yu , Li Qingdang
Published: January 2023

To address the problem of lignin membrane fouling caused by dynamic cross-flow in the process of retaining and concentrating the black liquor byproduct of papermaking, this paper uses three different rotating structures (vane, disk and propeller) to increase the surface shear force and filtration flux of the membrane. In this paper, under different rotating speeds and different transmembrane pressure differences, numerical simulations were conducted on the shear forces generated by the three structures and the retention process on the surface of the membrane. The variation laws were also studied and compared. Under the same filtration conditions, the vane structure demonstrates better results than the propeller and disk structures in terms of increasing filtration flux. Based on the result, the vane shear force was simulated in terms of changing the particle deposition, and compared with vane rotating speeds of 100–700 r/min, the surface particle deposition of the membrane was significantly reduced at a rotating speed of 800 r/min. Finally, the numerical simulation results were experimentally validated to ensure the accuracy of the simulation. The findings provide a theoretical basis and practical value for solving the problem of lignin membrane fouling caused by dynamic cross-flow in the process of retaining and concentrating the black liquor byproduct of papermaking.
The Relationship between Microstructure and Mechanical Properties of PBST Two-Component Crystalline Random Copolymers with Different BT Contents
Authors: Gang Mingjun , Wang Yuanxia , Zhang Yu , Liu Lizhi , Shi Ying
Published: January 2023

The mechanical properties of two-component crystalline random copolymers are primarily based on their microstructure. At the same time, the influence of the composition on the crystallization behavior and crystal structure of these materials is also well known. Thus, in this study, a poly (butylene succinate-co-butylene terephthalate) random copolymer (PBST) with different molar ratios of butylene terephthalate (BT) was prepared. A systematic analysis of the crystallization behavior, crystal structure, and mechanical properties of PBST with different BT contents was carried out using WAXD, SAXS, and DSC analyses. The investigations showed that PBST-37.5 containing 37.5 mol% of BT content had the lowest strength and highest elasticity among the different compositions. This was because the two-component crystallization of poly (butylene terephthalate) (PBT) and poly (butylene succinate) (PBS) was greatly inhibited at the corresponding BT composition and the crystal growth was the least perfect, imparting poor strength to the PBT-37.5. Alternately, when the content of BT was 32.5 mol% in the PBST, the PBS segment could crystallize, and both PBT and PBS crystals were formed in the PBST-32.5. Thus, PBST-32.5 showed a higher material hardness than PBST-37.5. In contrast, when the BT content was greater than 37.5 mol% in the PBST, only PBT crystals existed in the PBST copolymer. Further, as the BT content increased, the crystal size of PBT gradually increased, which led to a closer packing of the crystal arrangement, increasing the crystallinity. This led to a gradual increase in the strength of the PBST material and a gradual decrease in its elasticity.
Thermal, Lighting and IAQ Control System for Energy Saving and Comfort Management
Authors: Zanoli Silvia Maria , Pepe Crescenzo
Published: January 2023

The present work proposes a simulation and control framework for home and building automation, focusing on heating, ventilating, and air conditioning processes. Control systems based on different advanced control architectures and different control policies are simulated and compared, highlighting control performances, and energy-saving results in terms of CO2 emissions reduction. Heat, lighting, and natural ventilation phenomena were modelized through first-principles and empirical equations, obtaining a reliable and flexible simulation framework. Energy-consuming and green energy-supplying renewable sources were integrated into the framework, e.g., heat pumps, artificial lights, fresh air flow, and natural illuminance. Different control schemes are proposed, based on proportional–integral–derivative advanced control architectures and discrete event dynamic systems-based supervisors; different control specifications are included, resulting in a multi-mode control system. The specifications refer to energy savings and comfort management, while minimizing overall costs. Comfort specifications include thermal comfort, lighting comfort, and a good level of indoor air quality. Simulations on different scenarios considering various control schemes and specifications show the reliability and soundness of the simulation and control framework. The simulated control and energy performances show the potential of the proposed approach, which can provide energy-saving results greater or equal to 6 [%] (in each season) and 19 [%] (in one year) with respect to more standard approaches.
Application of the Heat Penetration Distance in the Design of the Hole Spacing of Ground-Coupled Heat Pumps
Authors: Wei Ting , Tao Yuezan , Zhang Yameng , Ren Honglei , Lin Fei
Published: January 2023

Due to issues such as heat accumulation, the site area, and project investment, the reasonable determination of the hole spacing for heat exchangers has become one of the key design points of the ground-coupled heat pump system. Based on the definition of heat penetration in heat transfer and the research method of the inverse problem, a direct algorithm of the heat penetration distance in the aquifer was proposed using the analytical solution to the mathematical model for one-dimensional heat convection–conduction problems. Taking a vertical ground-coupled heat pump project in Hefei, Anhui Province, China, as an example, a three-dimensional hydro-thermal coupling numerical simulation model was established, and the influence radius during the refrigeration and heating periods under the action of a single borehole heat exchanger was determined. Comparing the heat penetration distance with the influence radius, the results show that the relative errors of the results obtained by the two methods are less than 10%, which verifies the rationality and effectiveness of the calculated penetration distance in the aquifer. At the end of the cooling or heating period, the heat penetration distance in the aquifer is calculated to be 7.59 m. Therefore, the proposed method is straightforward and efficient, which can provide a convenient approach to determining the reasonable hole spacing of the heat pump system.
Mesh Stiffness and Nonlinear Dynamic Model for a Gear Drive with Revolute Pair Clearance
Authors: Huang Juan , Hu Bo , Sun Songlin , Xiao Mingtao , Peng Caiwang , Wang Hongbing
Published: January 2023

Bearings and other revolute pairs in gear drives will form clearances due to wear after working for a long time, which will aggravate the vibration and noise of the gear. Therefore, taking the gear drives with revolute pair clearance as the research object, the calculation formulas of the backlash and contact ratio is derived, and the time-varying mesh stiffness model considering the clearance is presented in this work. Then, a nonlinear dynamic model for the gear drives with revolute pair clearance is proposed by combining the backlash, contact ratio and the time-varying mesh stiffness. The effects of the clearance on the meshing stiffness, load sharing factor and nonlinear behavior are investigated. Results indicate that the revolute pair clearance weakens the meshing stiffness and increases working hours in single teeth contact area, thereby increasing the risk of premature failure of the gear drive. In addition, the revolute pair clearance has negligible effect on the nonlinear behavior of gear pair in low-speed running, but it can obviously change the bifurcation behavior and aggravate the vibration of the gear drive.
On Unit Exponential Pareto Distribution for Modeling the Recovery Rate of COVID-19
Authors: Haj Ahmad Hanan , Almetwally Ehab M. , Elgarhy Mohammed , Ramadan Dina A.
Published: January 2023

In 2019, a new lethal and mutant virus (COVID-19) spread around the world, causing the deaths of millions of people. COVID-19 demonstrates that scientists are involved in significant research efforts to face bacteria with less effort than that dedicated to viruses. Since then, engineers and bio-materials scientists have been trying to develop antiviral research and find a suitable effective medication. Strategies and opportunities for interference diagnostics, treatment strategies, and predicting future factors became mandatory. From a statistical point of view, estimating and modelling these factors play an important role in preventing future viral epidemics. In this article, modelling the recovery rate of COVID-19 is investigated through a new distribution which is called the unit exponential Pareto distribution. The new continuous distribution with three parameters displays a prominent level of flexibility to model decreasing, symmetric, and asymmetric data with a monotone failure rate. The recovery rates of COVID-19 in Turkey and France were examined; moreover, milk production data and components’ failure rates are presented for data modeling. The obtained results proved the superiority of the newly suggested model compared to other unit-based distributions. Several statistical features are studied such as the quantile function, the moments, the moment-generating function, some entropy measures, the ordered statistics, the stress–strength, and stochastic ordering. Two classical estimation methods are used in addition to the Bayesian method. The statistical features and estimation analysis are evaluated using numerical and simulation techniques. As a result, we obtain the efficiency of using the Bayesian method over the classical ones, with respect to the bias, average squared error, and the length of confidence intervals for the unknown parameters.
Development and Effectiveness Testing of a Novel 3D-Printed Multi-Material Orthosis in Nurses with Plantar Foot Pain
Authors: Chhikara Komal , Sidhu Sarabjeet Singh , Gupta Shubham , Saharawat Sakshi , Kataria Chitra , Chanda Arnab
Published: January 2023

Plantar foot pain is one of the most common musculoskeletal conditions affecting the foot. It is regularly experienced by the population with occupations that require prolonged standing hours, especially in nurses. The etiology of plantar foot pain remains unclear, but it is likely to be multi-factorial, with many associated risk factors including increased hours of standing. Orthoses and insoles are often recommended to plantar foot pain patients, however with minimal scientific advancements and limited customizations. In this study, a novel 3D-printed multi-material customized foot orthosis was developed, and its effectiveness on plantar foot pain reduction and functional ability improvement was studied in the nursing population. A total of thirty-six subjects were recruited and were randomized into two groups. The experimental group received the novel 3D-printed multi-material customized foot orthosis, whereas the control group received the standard-of-care (or traditional) intervention. Pre-test and the post-test scores of pains, functional ability and plantar pressure were observed using SPSS software. Improvements were observed in both of the groups; however, better improvements were seen in the experimental group. Overall, the novel 3D printing-based customized foot orthosis showed significant efficacy in reducing plantar foot pain and pressure, and also in increasing functional ability in the nursing population as compared to the traditional method.
Taphonomy and Palaeoecology of Quaternary Vertebrates: Advances in Fossil and Experimental Studies
Authors: Stoetzel Emmanuelle , Ochoa Janine , Rofes Juan
Published: January 2023

Since the founding work of Efremov in 1940 [...]
From Secular Spaces to Religious Places: The Case of the Romanian Orthodox Place of Worship of Lunghezza (Rome, Italy)
Authors: Cozma Ioan , Federici Angelica , Giorda Maria Chiara , Omenetto Silvia
Published: January 2023

The purpose of this article is to study the Romanian Orthodox place of worship of Lunghezza in Rome, utilizing the expression ‘shared religious place’ and thus referring to the shift from secular to religious and asserting that it is now a camouflaged religious place. Using GIS mapping and Digital Humanities methods and tools, the paper analyses the geographical presence of Orthodox Romanians in the Metropolitan City of Rome territory and the architectural typologies of their places of worship. The history and geography of the church in Lunghezza, a former stable converted into a house of worship, reveals the form of the resilience of the Romanian Orthodox parishes, forced to find various and compelling solutions in order to survive as places of worship.
Trade Credit Management and Profitability of Jordanian Manufacturing Firms
Authors: Al-Eitan Ghaith N. , Khanji Ibrahim M. , Saraireh Shadi A.
Published: January 2023

The significant role of Small and Medium Enterprises (SMEs) in the growth of the economy has been well-documented in the past few decades. Studies in literature have focused on the reasons behind the trade credit offerings and acceptance of SMEs, but empirical findings revealing the positive relationship between trade credit itself and profitability is still limited. Thus, in this paper, the trade credit effect on the profitability of SMEs from the side of supply and demand is examined. The paper focused on 38 SMEs in Amman Stock Exchange (ASE) for the years from 2009 to 2021. The obtained findings showed a positive relationship between accounts payable and profitability, which indicates that SMEs should establish long-term relationships with their suppliers to maintain credit. However, no clear relationship was found between accounts receivable and profitability, represented by ROE and ROA. Furthermore, financial leverage and size were revealed to impact the profitability of SMEs.
High-Accuracy and Low-Latency Tracker for UAVs Monitoring Tibetan Antelopes
Authors: Luo Wei , Li Xiaofang , Zhang Guoqing , Shao Quanqin , Zhao Yongxiang , Li Denghua , Zhao Yunfeng , Li Xuqing , Zhao Zihui , Liu Yuyan , Li Xiaoliang
Published: January 2023

As the habitat areas of Tibetan antelopes usually exhibit poaching and unpredictable risks, combining target recognition and tracking with intelligent Unmanned Aerial Vehicle (UAV) technology is necessary to obtain the real-time location of injured Tibetan antelopes to better protect and rescue them. (1) Background: The most common way to track an object is to detect each frame of it, and it is not necessary to run the object tracker and classifier at the same rate, because the speed for them to change class is slower than objects move. Especially in the edge reasoning scene, UAV real-time monitoring requires to seek a balance between the frame rate, latency, and accuracy. (2) Methods: A backtracking tracker is proposed to recognize Tibetan antelopes which generates motion vectors through stored optical flow, achieving faster target detection. The lightweight You Only Look Once X (YOLOX) is selected as the baseline model to reduce the dependence on hardware configuration and calculation cost while ensuring detection accuracy. Region-of-Interest (ROI)-to-centroid tracking technology is employed to reduce the processing cost of motion interpolation, and the overall processing frame rate is smoothed by pre-calculating the motions of different objects recognized. The On-Line Object Tracking (OLOT) system with adaptive search area selection is adopted to dynamically adjust the frame rate to reduce energy waste. (3) Results: using YOLOX to trace back in the native Darkenet can reduce latency by 3.75 times, and the latency is only 2.82 ms after about 10 frame hops, with the accuracy being higher than YOLOv3. Compared with traditional algorithms, the proposed algorithm can reduce the tracking latency of UAVs by 50%. By running and comparing in the onboard computer, although the proposed tracker is inferior to KCF in FPS, it is significantly higher than other trackers and is obviously superior to KCF in accuracy. (4) Conclusion: A UAV equipped with the proposed tracker effectively reduces reasoning latency in monitoring Tibetan antelopes, achieving high recognition accuracy. Therefore, it is expected to help better protection of Tibetan antelopes.
Dry Matter Yield and Nitrogen Content Estimation in Grassland Using Hyperspectral Sensor
Authors: Nishikawa Hitoshi , Oenema Jouke , Sijbrandij Fedde , Jindo Keiji , Noij Gert-Jan , Hollewand Frank , Meurs Bert , Hoving Idse , van der Vlugt Peter , Bouten Max , Kempenaar Corné
Published: January 2023

Estimation of Dry Matter Yield (DMY) and Nitrogen Content (NC) in forage is a big concern for growers. In this study, an estimation model of DMY and NC using Visible and Near Infrared (V-NIR) spectroscopy was developed. An adequate number of grass samples (5078) of perennial ryegrass (Lolium perenne), collected from Dutch grassland in 2019 and 2020 were sensed with a hyperspectral sensor, while grass height was recorded in situ by an ultrasonic sensor mounted on a tractor. The samples were treated with Artificial Intelligence (AI) techniques. PCA based feature selection was applied first, revealing that visible green wavelength (around 500 nm) and red edge wavelength (around 700 nm) were enough to express the overall variability of the dataset. Then, Feature Importance analysis of Random Forest Regressor showed that NIR wavelengths (around 910, 960 and 990nm) were the most sensitive in DMY estimation, while red edge (around 710 nm) and visible orange wavelengths (around 610 nm) were the most related to NC estimation. Finally, SHAP (SHapley Additive exPlanations) analysis was applied to the Random Forest estimation models, resulting in the visualization of wavelength selection, thus assisting in the interpretation of the results and the intermediate processes. Overall, this method can lead to the reduction of the number of wavelengths to be measured in the field and thus, to the possible development of a low cost hyperspectral sensor for the above purposes.
Estimation of Earth Rotation Parameters and Prediction of Polar Motion Using Hybrid CNN–LSTM Model
Authors: Yu Kehao , Yang Kai , Shen Tonghui , Li Lihua , Shi Haowei , Song Xu
Published: January 2023

The Earth rotation parameters (ERPs), including polar motion (PMX and PMY) and universal time (UT1-UTC), play a central role in functions such as monitoring the Earth’s rotation and high-precision navigation and positioning. Variations in ERPs reflect not only the overall state of movement of the Earth, but also the interactions among the atmosphere, ocean, and land on the spatial and temporal scales. In this paper, we estimated ERP series based on very long baseline interferometry (VLBI) observations between 2011–2020. The results show that the average root mean square errors (RMSEs) are 0.187 mas for PMX, 0.205 mas for PMY, and 0.022 ms for UT1-UTC. Furthermore, to explore the high-frequency variations in more detail, we analyzed the polar motion time series spectrum based on fast Fourier transform (FFT), and our findings show that the Chandler motion was approximately 426 days and that the annual motion was about 360 days. In addition, the results also validate the presence of a weaker retrograde oscillation with an amplitude of about 3.5 mas. This paper proposes a hybrid prediction model that combines convolutional neural network (CNN) and long short-term memory (LSTM) neural network: the CNN–LSTM model. The advantages can be attributed to the CNN’s ability to extract and optimize features related to polar motion series, and the LSTM’s ability to make medium- to long-term predictions based on historical time series. Compared with Bulletin A, the prediction accuracies of PMX and PMY are improved by 42% and 13%, respectively. Notably, the hybrid CNN–LSTM model can effectively improve the accuracy of medium- and long-term polar motion prediction.
Spatial–Temporal Evolutions of Ecological Environment Quality and Ecological Resilience Pattern in the Middle and Lower Reaches of the Yangtze River Economic Belt
Authors: Peng Lu , Wu Haowei , Li Zhihui
Published: January 2023

Ecological environment quality and resilience assessment is an important prerequisite for ensuring the coordination and stability of socio-economic development and eco-environment protection. Remote sensing technology has provided new approaches for quantitatively evaluating regional ecological environment quality and resilience rapidly, accurately, and objectively. Taking the middle and lower reaches of the Yangtze River Economic Belt (YREBML) as an example, to assess ecological environment quality, this study calculated the remote sensing ecological index (RSEI) based on the Google Earth Engine using Moderate Resolution Imaging Spectroradiometer (MODIS) data with a spatial resolution of 500 m during 2000–2020. An evaluation index to assess ecological resilience and its spatial pattern based on the RSEI of 2000–2020 was then constructed. The evaluation index was constructed from two dimensions, including the sensitivity and adaptability of the RSEI. Finally, this study identified key factors that affect ecological residence based on a structural equation model. The results showed that the overall RSEI was at moderate and good levels in the YREBML during 2000–2020, accounting for more than 85% of the total area. Its spatial characteristics showed that the RSEI was higher in the middle reaches than in the lower reaches of the YREB, and higher in the south than in the north. The overall RSEI in the YREBML showed a decreasing trend during 2000–2020, with 54.36% of the region improving and 45.64% declining. Areas with declining RSEI were concentrated in Anhui, while the increasing RSEI was observed in Zhejiang. In addition, the spatial pattern of ecological resilience was characterized by high resilience in the north and east, and low resilience in the south and west. High resilience areas accounted for 40.48% of the YREBML, mainly contributed by Jiangxi and Hunan provinces. The driving factors analysis results indicated that economic development, natural disaster risk, and environmental pollution would further affect ecological resilience of urban systems. This study provides more scientific and effective data support for ecological environment monitoring and governance.
Application of Combined Filtering in Thunder Recognition
Authors: Wang Yao , Yang Jing , Zhang Qilin , Zeng Jinquan , Mu Boyi , Du Junzhi , Li Zhekai , Shao Yuhui , Wang Jialei , Li Zhouxin
Published: January 2023

Thunder recognition is of great interest in lightning detection and physics and is widely used in short-range lightning location. However, due to the complexity of thunder, any single filtering method that is used in traditional speech noise reduction technology cannot identify well thunder from complicated background noise. In this study, the impact of four different filters on thunder recognition is compared, including low-pass filtering, least-mean-square adaptive filtering, spectral subtraction filtering, and Wiener filtering. The original acoustic signal and that filtered using different techniques are applied to a convolutional neural network, in which the thunder and background noise are classified. The results indicate that a combination of spectral subtraction and a low-pass filter performs the best in thunder recognition. The signal-to-noise ratio can be significantly improved, and the accuracy of thunder recognition (93.18%) can be improved by 3.8–18.6% after the acoustic signal is filtered using the combined filtering method. In addition, after filtering, the endpoints of a thunder signal can be better identified using the frequency domain sub-band variance algorithm.
GNSS Observation Generation from Smartphone Android Location API: Performance of Existing Apps, Issues and Improvement
Authors: Zangenehnejad Farzaneh , Jiang Yang , Gao Yang
Published: January 2023

Precise position information available from smartphones can play an important role in developing new location-based service (LBS) applications. Starting from 2016, and after the release of Nougat version (Version 7) by Google, developers have had access to the GNSS raw measurements through the new application programming interface (API), namely android.location (API level 24). However, the new API does not provide the typical GNSS observations directly (e.g., pseudorange, carrier-phase and Doppler observations) which have to be generated by the users themselves. Although several Apps have been developed for the GNSS observations generation, various data analyses indicate quality concerns, from biases to observation inconsistency in the generated GNSS observations output from those Apps. The quality concerns would subsequently affect GNSS data processing such as cycle slip detection, code smoothing and ultimately positioning performance. In this study, we first investigate algorithms for GNSS observations generation from the android.location API output. We then evaluate the performances of two widely used Apps (Geo++RINEX logger and GnssLogger Apps), as well as our newly developed one (namely UofC CSV2RINEX tool) which converts the CSV file to a Receiver INdependent Exchange (RINEX) file. Positioning performance analysis is also provided which indicates improved positioning accuracy using our newly developed tool. Future work finding out the potential reasons for the identified misbehavior in the generated GNSS observations is recommended; it will require a joint effort with the App developers.
Leveraging Blockchain Technology for Ensuring Security and Privacy Aspects in Internet of Things: A Systematic Literature Review
Authors: Zubaydi Haider Dhia , Varga Pál , Molnár Sándor
Published: January 2023

As the Internet of Things (IoT) concept materialized worldwide in complex ecosystems, the related data security and privacy issues became apparent. While the system elements and their communication paths could be protected individually, generic, ecosystem-wide approaches were sought after as well. On a parallel timeline to IoT, the concept of distributed ledgers and blockchains came into the technological limelight. Blockchains offer many advantageous features in relation to enhanced security, anonymity, increased capacity, and peer-to-peer capabilities. Although blockchain technology can provide IoT with effective and efficient solutions, there are many challenges related to various aspects of integrating these technologies. While security, anonymity/data privacy, and smart contract-related features are apparently advantageous for blockchain technologies (BCT), there are challenges in relation to storage capacity/scalability, resource utilization, transaction rate scalability, predictability, and legal issues. This paper provides a systematic review on state-of-the-art approaches of BCT and IoT integration, specifically in order to solve certain security- and privacy-related issues. The paper first provides a brief overview of BCT and IoT’s basic principles, including their architecture, protocols and consensus algorithms, characteristics, and the challenges of integrating them. Afterwards, it describes the survey methodology, including the search strategy, eligibility criteria, selection results, and characteristics of the included articles. Later, we highlight the findings of this study which illustrates different works that addressed the integration of blockchain technology and IoT to tackle various aspects of privacy and security, which are followed by a categorization of applications that have been investigated with different characteristics, such as their primary information, objective, development level, target application, type of blockchain and platform, consensus algorithm, evaluation environment and metrics, future works or open issues (if any), and further notes for consideration. Furthermore, a detailed discussion of all articles is included from an architectural and operational perspective. Finally, we cover major gaps and future considerations that can be taken into account when integrating blockchain technology with IoT.
Benchmarking the Effects on Human–Exoskeleton Interaction of Trajectory, Admittance and EMG-Triggered Exoskeleton Movement Control
Authors: Rodrigues-Carvalho Camila , Fernández-García Marvin , Pinto-Fernández David , Sanz-Morere Clara , Barroso Filipe Oliveira , Borromeo Susana , Rodríguez-Sánchez Cristina , Moreno Juan C. , del-Ama Antonio J.
Published: January 2023

Nowadays, robotic technology for gait training is becoming a common tool in rehabilitation hospitals. However, its effectiveness is still controversial. Traditional control strategies do not adequately integrate human intention and interaction and little is known regarding the impact of exoskeleton control strategies on muscle coordination, physical effort, and user acceptance. In this article, we benchmarked three types of exoskeleton control strategies in a sample of seven healthy volunteers: trajectory assistance (TC), compliant assistance (AC), and compliant assistance with EMG-Onset stepping control (OC), which allows the user to decide when to take a step during the walking cycle. This exploratory study was conducted within the EUROBENCH project facility. Experimental procedures and data analysis were conducted following EUROBENCH’s protocols. Specifically, exoskeleton kinematics, muscle activation, heart and breathing rates, skin conductance, as well as user-perceived effort were analyzed. Our results show that the OC controller showed robust performance in detecting stepping intention even using a corrupt EMG acquisition channel. The AC and OC controllers resulted in similar kinematic alterations compared to the TC controller. Muscle synergies remained similar to the synergies found in the literature, although some changes in muscle contribution were found, as well as an overall increase in agonist-antagonist co-contraction. The OC condition led to the decreased mean duration of activation of synergies. These differences were not reflected in the overall physiological impact of walking or subjective perception. We conclude that, although the AC and OC walking conditions allowed the users to modulate their walking pattern, the application of these two controllers did not translate into significant changes in the overall physiological cost of walking nor the perceived experience of use. Nonetheless, results suggest that both AC and OC controllers are potentially interesting approaches that can be explored as gait rehabilitation tools. Furthermore, the INTENTION project is, to our knowledge, the first study to benchmark the effects on human–exoskeleton interaction of three different exoskeleton controllers, including a new EMG-based controller designed by us and never tested in previous studies, which has made it possible to provide valuable third-party feedback on the use of the EUROBENCH facility and testbed, enriching the apprenticeship of the project consortium and contributing to the scientific community.
Lightweight Multimodal Domain Generic Person Reidentification Metric for Person-Following Robots
Authors: Syed Muhammad Adnan , Ou Yongsheng , Li Tao , Jiang Guolai
Published: January 2023

Recently, person-following robots have been increasingly used in many real-world applications, and they require robust and accurate person identification for tracking. Recent works proposed to use re-identification metrics for identification of the target person; however, these metrics suffer due to poor generalization, and due to impostors in nonlinear multi-modal world. This work learns a domain generic person re-identification to resolve real-world challenges and to identify the target person undergoing appearance changes when moving across different indoor and outdoor environments or domains. Our generic metric takes advantage of novel attention mechanism to learn deep cross-representations to address pose, viewpoint, and illumination variations, as well as jointly tackling impostors and style variations the target person randomly undergoes in various indoor and outdoor domains; thus, our generic metric attains higher recognition accuracy of target person identification in complex multi-modal open-set world, and attains 80.73% and 64.44% Rank-1 identification in multi-modal close-set PRID and VIPeR domains, respectively.