bluuebunny/crossref_metadata_2025 huggingface dataset:
Adaptive Guided Equilibrium Optimizer with Spiral Search Mechanism to Solve Global Optimization Problems
Authors: Ding Hongwei , Liu Yuting , Wang Zongshan , Jin Gushen , Hu Peng , Dhiman Gaurav
Published: August 2023

The equilibrium optimizer (EO) is a recently developed physics-based optimization technique for complex optimization problems. Although the algorithm shows excellent exploitation capability, it still has some drawbacks, such as the tendency to fall into local optima and poor population diversity. To address these shortcomings, an enhanced EO algorithm is proposed in this paper. First, a spiral search mechanism is introduced to guide the particles to more promising search regions. Then, a new inertia weight factor is employed to mitigate the oscillation phenomena of particles. To evaluate the effectiveness of the proposed algorithm, it has been tested on the CEC2017 test suite and the mobile robot path planning (MRPP) problem and compared with some advanced metaheuristic techniques. The experimental results demonstrate that our improved EO algorithm outperforms the comparison methods in solving both numerical optimization problems and practical problems. Overall, the developed EO variant has good robustness and stability and can be considered as a promising optimization tool.
Non-Deceptive Placebos Can Promote Acts of Kindness: A Randomized Controlled Trial
Authors: Schienle Anne , Unger Isabella
Published: August 2023

Placebos have often been used to reduce emotional distress but rarely to increase positive feelings. The present study investigated whether a placebo can promote acts of kindness (AoKs) that are associated with emotional well-being. A total of 160 university students were asked to perform an AoK daily for one week. They evaluated their emotional state (feelings of pleasantness, arousal, satisfaction) directly before and after the AoKs. This was monitored via a smartphone app. One group performed each AoK after taking a non-deceptive placebo; the other group received no placebo. Before and after the one-week program, the participants completed three questionnaires that assessed satisfaction with life, positive/negative affect, and flourishing. The participants reported higher pleasantness directly after engaging in an AoK and more satisfaction with life after the program. The motivation to carry out AoKs decreased strongly over the week. However, placebo receivers completed more AoKs than the no-placebo group. The results indicate that placebo treatment can promote the performance of acts of kindness.
Fusion Recalibration Method for Addressing Multiplicative and Additive Effects and Peak Shifts in Analytical Chemistry
Authors: Jiang Dapeng , Zhang Yizhuo , Ge Yilin , Wang Keqi
Published: August 2023

Analytical chemistry relies on the qualitative and quantitative analysis of multivariate data obtained from various measurement techniques. However, artifacts such as missing data, noise, multiplicative and additive effects, and peak shifts can adversely affect the accuracy of chemical measurements. To ensure the validity and accuracy of results, it is crucial to preprocess the data and correct for these artifacts. This paper proposes a fusion recalibration algorithm, called Spectral Offset Recalibration (SOR), that combines the Extended Multiplicative Signal Correction (EMSC) and Correlation-Optimized Warping (COW) algorithms to address both multiplicative and additive effects and peak shifts. The algorithm incorporates prior spectroscopic knowledge to down-weight or disregard spectral regions with strong absorption or significant distortion caused by peak alignment algorithms. Experimental validation on wood NIR datasets and simulated datasets demonstrates the effectiveness of the proposed method. The fusion recalibration approach offers a comprehensive solution for accurate analyses and predictions in analytical chemistry by mitigating the impact of artifacts.
Association of Myocardial Changes and Gene Expression of the NFATC1 and NFATC4—Calcineurin Signaling Pathway in Children with Bicuspid Aortic Valve
Authors: Kamenshchyk Andrii , Gonchar Margaryta , Oksenych Valentyn , Kamyshnyi Aleksandr
Published: August 2023

Background: The role of NFATC gene expression in bicuspid aortic valve (BAV) progression is not fully understood. The aim of this study is to determine the significance of NFATC1 and NFATC4 gene expression for myocardial changes in children with BAV. Methods: In 47 children with BAV, the standard Doppler echocardiographic characteristics were detected, and the expression of the NFATC1 and NFATC4 genes was studied. Results: Posterior wall thickness in diastole (PWTd) and aortic valve peak pressure gradient (AoPPG) in BAV patients were significantly higher compared to healthy controls (PWTd median (min–max), 9 (7–10) mm vs. 7 (6–8) mm; and AoPPG median (min–max), 7.79 (2.98–15.09) mm Hg vs. 2.94 (2.42–3.72) mm Hg). The expression of the NFATC1 gene in BAV children was significantly higher compared to NFATC4 (NFATC1 median (min–max); 70.88 (8.79–106.51) e.u. vs. 7.72 (1.74–22.67) e.u., respectively p < 0.05). A significant correlation of NFATC1 expression with Ao found (R = +0.53, p < 0.05). In BAV patients with PWTd > 8 mm and Ao > 21 mm the NFATC1 expression was significantly higher compared to those with PWTd ≤ 8 mm and Ao ≤ 21 mm (NFATC1 median (min–max); 45.49 (5.01–101.52) e.u. vs. 15.53 (2.36–44.40) e.u., p < 0.05 and 81.11 (20.27–101.10) e.u. mm vs. 12.16 (2.40–45.49) e.u., p < 0.05, respectively). Conclusion: In children with BAV the high expression of the NFATC1 calcineurin signaling pathway gene is associated with elevated PWTd and Ao.
The Barriers Assessment Tool—A Patient-Centered Measure of Adherence Barriers in Pediatric Kidney Transplantation
Authors: Varnell Charles D. , Hooper David K. , Mara Constance A. , Modi Avani C. , Rich Kristin L.
Published: August 2023

Objective: Assessing barriers to adherence provides helpful information to clinicians. The objective of this study was to describe the clinical utility of the Barriers Assessment Tool (BAT) using clinical data for a large, midwestern U.S. pediatric kidney transplant program. Methods: Focus group and clinical data were obtained during post-transplant medical visits. Qualitative and quantitative assessment methods were utilized to describe patient and caregiver feedback on the BAT, clinical utility, concordance between reporters, and the effect of interventions on subsequent assessment and electronically measured adherence. Results: Patients were willing to discuss adherence issues with their care team. There was substantial agreement between patients and caregivers at two timepoints. If a barrier was not addressed, 89.6% (43/48) of patients and 85.9% (67/78) of caregivers reported the same BAT scores from the first to second assessment. When barriers were addressed with a clinic-based intervention, 82% of caregivers reported no adherence barriers. No significant change was found for patient-reported barriers. Conclusions: Standardized assessment of barriers to medication adherence provides actionable information to clinicians. Standardized assessment of adherence barriers may give clinicians opportunities to help patients and caregivers overcome these barriers which can decrease risk of rejection.
Prenatal Diagnosis and Pregnancy Termination in Jewish and Muslim Women with a Deaf Child in Israel
Authors: Amiel Aliza , Na’amnih Wasef , Tarabeih Mahdi
Published: August 2023

Deafness is the most common sensory disability in humans, influencing all aspects of life, However, early diagnosis of hearing impairment and initiating the rehabilitation process are of great importance to enable the development of language and communication as soon as possible. We examined the differences in attitudes towards performing prenatal invasive tests and pregnancy terminations in Jewish and Muslim women in Israel due to deafness. Overall, 953 Israeli women, aged 18–46 years with a mean age of 32.0 (SD = 7.12), were enrolled. Of those, 68.7% were city dwellers and 31.3% were village dwellers, and 60.2% were Muslim women and 39.8% were Jewish women. All participants had a child with a hearing impairment or deafness. The group with no genetic hearing loss performed more prenatal invasive tests and pregnancy terminations than those with genetic hearing loss in both ethnic groups. Jewish women performed more invasive prenatal tests and, consequently, a pregnancy termination. Secular Jewish women more frequently underwent pregnancy terminations due to fetal deafness. Further genetic counseling and information concerning IVF and PGD procedures should be provided to the Muslim population.
Dose Rate Effect on Cell Survival in BNCT
Authors: Hirose Katsumi , Sato Mariko , Ichise Koji , Aoki Masahiko
Published: August 2023

The output constancy of the accelerator used for boron neutron capture therapy (BNCT) is essential to ensuring anti-tumor efficacy and safety. BNCT as currently practiced requires a wide variety of beam quality assessments to ensure that RBE dose errors are maintained within 5%. However, the necessity of maintaining a constant beam dose rate has not been fully discussed. We therefore clarified the effect of different physical dose rates of the accelerator BNCT on biological effects. SAS and A172 cells exposed to 10B-boronophenylalanine were irradiated using a neutron beam (normal operating current, 100 μA) at the Aomori Quantum Science Center. Thermal neutron flux was attenuated to 50.0 ± 0.96% under 50 μA irradiation compared to that under 100 μA irradiation. Cells were given physical doses of 1.67 and 3.36 Gy at 30 and 60 mC, respectively, and survival was significantly increased after 50 μA irradiation for both cell types (p = 0.0052 for SAS; p = 0.046 for A172, for 60 mC). Differences in accelerator BNCT beam dose rates have non-negligible effects on biological effects. Dose rate fluctuations and differences should not be easily permitted to obtain consistent biological effects.
Numerical Computation of Hydrodynamic Characteristics of an Automated Hand-Washing System
Authors: Le Thanh-Long , Vuong Thi-Hong-Nhi , Phung Tran-Hanh
Published: August 2023

The aim of this study is to develop a physical model and investigate the bactericidal effect of an automated hand-washing system through numerical computation, which is essential in areas affected by COVID-19 to ensure safety and limit the spread of the pandemic. The computational fluid dynamics approach is used to study the movement of the solution inside the hand-washing chamber. The finite element method with the k-ε model is applied to solve the incompressible Navier–Stokes equations. The numerical results provide insights into the solution’s hydrodynamic values, streamlines, and density in the two cases of with a hand and without a hand. The pressure and mean velocity of the fluid in the hand-washing chamber increases when the inlet flow rates increase. When the hand-washing chamber operates, it creates whirlpools around the hands, which remove bacteria. In addition, the liquid inlet flow affects the pressure in the hand-washing chamber. The ability to predict the hydraulic and cleaning performance efficiencies of the hand-washing chamber is crucial for evaluating its operability and improving its design in the future.
Relationships between Environmental Factors and Functional Traits of Macrophyte Assemblages in Running Waters of Greece
Authors: Stefanidis Konstantinos , Oikonomou Anthi , Dimitrellos Georgios , Tsoukalas Dionysios , Papastergiadou Eva
Published: August 2023

The analysis of plant trait composition has raised significant interest among freshwater ecologists as a complementary approach for assessing the effects of environmental change on ecosystem functions. In this study, we investigated patterns of functional traits of the aquatic macrophyte assemblages of 74 lotic ecosystems of Greece, and we identified associations between species traits and environmental variables (hydromorphological and physicochemical parameters) through testing the hypothesis that the environmental features determine the spatial structure of traits. We allocated 12 traits to a total of 39 hydrophyte species, and we conducted RLQ and fourth corner analysis to explore relationships between species, trait composition, and environmental gradients. Based on the results of the RLQ, a hierarchical cluster analysis was conducted to identify groups of plants that share common trait characteristics. Plants were discriminated into five discrete groups based mostly on their life form (e.g., free-floating, rooted submerged etc.) and their ecological preference for nitrogen levels. Hydromorphological parameters had a higher contribution than physicochemical variables in explaining the total variance of the trait data, with water abstraction, channel substrate, and hydrologic alteration being the most important. Our analysis did not reveal significant bivariate relationships between single traits and environmental parameters, although the five groups of macrophyte assemblages appeared to associate with certain environmental gradients. Free-floating and emergent plants were related to higher concentrations of nutrients, whereas rooted submerged plants were related to higher oxygen concentration and increased pH. In addition, free-floating plants were highly associated with metrics of hydromorphological change. Our findings showed clear discrimination of macrophytes based on their functional composition and association of traits with environmental gradients. Thus, further research could explore whether macrophyte functional groups can serve as indicators of environmental change and the overall ecosystem health.
Perceptions of Online Learning Implementation in Dental Education during the COVID-19 Pandemic: A Cross-Sectional Study of Dental School Faculty Members in Southeast Asia
Authors: Wimardhani Yuniardini Septorini , Indrastiti Ratna Kumala , Ayu Adrianti Primata , Soegyanto Anandina Irmagita , Wardhany Indriasti Indah , Subarnbhesaj Ajiravudh , Nik Mohd Rosdy Nik Mohd Mazuan , Do Thao Thi
Published: August 2023

Objective: To assess the perceptions of faculty members from dental schools in Southeast Asian countries regarding the implementation of online learning during the COVID-19 pandemic. Methods: A previously implemented questionnaire comprising 43 questions was utilized in this study. Lecturers from four universities in Southeast Asia were invited to participate in the study. Statistical analysis: The data were analyzed using SPSS version 25.0 through several types of comparative and correlation analyses. Results: There were 183 lecturers who participated in the study. The overall responses suggest that the perceived effectiveness of online learning in dentistry was centered on a neutral value. The participants faced challenges when implementing online learning during the COVID-19 pandemic, with the lack of interaction being the most challenging factor. They agreed that online learning had many advantages, specifically in time flexibility and communication. The participants had stronger perceptions relating the advantages and opportunities of online teaching, and recognized that the effectiveness of offline teaching alone was limited. Conclusion: The perceptions of Southeast Asian dental school faculty members were inclined toward a positive outlook on blended learning for implementation in dentistry, as a means of providing opportunities to use online learning beyond COVID-19 in the future.
Informational Resilience in the Human Cognitive Ecology
Authors: Gahrn-Andersen Rasmus
Published: August 2023

Resilience is a basic trait of cognitive systems and fundamentally connected to their autopoietic organization. It plays a vital role in maintaining the identity of cognitive systems in the face of external threats and perturbances. However, when examining resilience in the context of autopoiesis, an overlooked issue arises: the autopoietic theory formulated by Maturana and Varela (1980) renders traditional Shannon information obsolete, highlighting that information should not be ascribed a role in cognitive systems in a general sense. This paper examines the current situation and suggests a possible way forward by exploring an affordance-based view on information, derived from radical cognitive science, which is exempted from Maturana and Varela’s critique. Specifically, it argues that the impact of social influence on affordance use is crucial when considering how resilience can manifest in informational relations pertaining to the human cognitive ecology.
Distance Correlation-Based Feature Selection in Random Forest
Authors: Ratnasingam Suthakaran , Muñoz-Lopez Jose
Published: August 2023

The Pearson correlation coefficient (ρ) is a commonly used measure of correlation, but it has limitations as it only measures the linear relationship between two numerical variables. The distance correlation measures all types of dependencies between random vectors X and Y in arbitrary dimensions, not just the linear ones. In this paper, we propose a filter method that utilizes distance correlation as a criterion for feature selection in Random Forest regression. We conduct extensive simulation studies to evaluate its performance compared to existing methods under various data settings, in terms of the prediction mean squared error. The results show that our proposed method is competitive with existing methods and outperforms all other methods in high-dimensional (p≥300) nonlinearly related data sets. The applicability of the proposed method is also illustrated by two real data applications.
Application of Successful EU Funds Absorption Models to Sustainable Regional Development
Authors: Šostar Marko , Ristanović Vladimir , de Alwis Chamaru
Published: August 2023

The research paper comprehensively and consistently addresses all relevant theoretical areas related to the topic and includes an extensive empirical analysis of the absorption of EU funds and their impact on the sustainable development of Croatia, Slovenia, Hungary, and Poland. The analysis aims to investigate the efficiency of the absorption of funds from the EU, the impact of these funds on regional development of countries, and the reasons for such impacts. The “Regional Development Model Based on EU Funds” was tested with the aim of applying the model to the Republic of Croatia, countries in the region, and other European countries, to achieve a higher level of absorption of financial resources from the available EU funds. Data for the empirical analysis were collected using a highly structured survey questionnaire completed by a sample of 244 respondents involved in the preparation and implementation of EU-funded projects. The contribution of economic science in theoretical terms arises from the development of scientific knowledge and ideas about the importance of increasing the number of development projects that will increase the absorption of funds from the European Union, thereby increasing economic activities in Croatia and the region. The expected contribution of economic science in the applied sense is based on the formulation of the “Regional Development Model Based on EU Funds”, which is based on the application of knowledge, good practices, and stakeholder experiences, considering relevant indicators from available sources. The greatest contribution is demonstrated through testing the “Regional Development Model Based on EU Funds”, which is applicable to the Republic of Croatia, countries in the region, and other European countries over a longer period. Finally, research into the impact of EU funds on the regional development of recipient countries is considerably less represented and very modest, and is only in the “upswing” of systematic scientific research. The research aims to fill the gaps in research and to encourage the thinking of key stakeholders responsible for regional development, who should eventually realize the importance of defining a regional policy aimed at EU funds as a key to regional development and reducing regional disparities within countries.
Administrative Processes Efficiency Measurement in Higher Education Institutions: A Scoping Review
Authors: Alvarez-Sández Dulce , Velázquez-Victorica Karla , Mungaray-Moctezuma Alejandro , López-Guerrero Aída
Published: August 2023

Universities, like any organization, must attend to the needs of the environment to provide quality services. Among the various aspects related to educational quality, administrative efficiency management has gained interest in recent times. This is due to the need to optimize resources and streamline the daily operations of an educational institution. This scoping review examines how efficiency is being measured in Higher Education Institutions (HEIs). Taking as a reference the proposed methodology by Arksey and O’Malley and the PRISMA Scr (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews) guide, we performed a search of the literature in the Scopus database from 2017 to 2022. As a result, different ways to measure administrative process efficiency were found, such as formulated models, methods, and indicators that show quantitative benefits. A significant finding was Lean or Six Sigma practices to improve administrative efficiency, in addition to the consideration of the interest group opinion through the application of measurement instruments to measure the impact on the user satisfaction level.
How Crosscutting Is the Energy Concept within Physics Teaching and Learning
Authors: Etkina Eugenia , Owen Jon , Planinsic Gorazd , Seeley Lane
Published: August 2023

Much of the attention on the crosscutting concepts within the Next-Generation Science Standards (NGSSs) have gone to their coherence across different STEM disciplines. In this paper, we raise the question of the coherence of the energy concept within the teaching and learning of physics itself. Our investigations of teachers’ and students’ approach to solving problems, where both mechanical and thermal energy play equally important roles, indicate that the separation of energy studies in different units (mechanics, thermodynamics, etc.) leads to a cognitive disconnect of the understanding of different energy types and the inability to explain processes that involve both mechanical and internal energy, especially when the internal energy of the living organisms that are associated with a process is involved. We also find that when students gain experience analyzing scenarios where thermal energy plays a subtle yet critical role in addition to mechanical energy, they are able to apply this understanding to novel scenarios.
Combined Unplugged and Educational Robotics Training to Promote Computational Thinking and Cognitive Abilities in Preschoolers
Authors: Montuori Chiara , Pozzan Gabriele , Padova Costanza , Ronconi Lucia , Vardanega Tullio , Arfé Barbara
Published: August 2023

Computational thinking (CT) learning activities are increasingly integrated in early-stage school curricula in several countries. Tools used to teach CT in early school years include unplugged coding—i.e., programming without computing devices—and educational robotics (ER)—i.e., giving instructions to a digitally controlled mechanical robot to perform specific actions in a physical environment. Past studies have shown that training coding skills through ER enhances first graders’ executive functions (EFs). Little is known, however, about the effects of ER interventions, alone or combined with un-plugged activities, on preschoolers’ CT and EF skills. In a cluster-randomized controlled trial, we assessed whether improvements in preschoolers’ coding skills, following interventions based on combinations of unplugged coding and ER, transfer to plugged (computer-based) coding abilities and to EFs such as planning, response inhibition, and visuo-spatial skills. Forty-seven preschoolers from four class groups, with no prior exposure to coding, were randomly assigned to an experimental (unplugged coding and ER, two classes) or control (standard school activities, two classes) instructional groups. Four coding tasks, one standardized planning task (Tower of London test), one standardized response inhibition task (NEPSY-II inhibition subtest), and one visuo-spatial standardized task (Primary Mental Ability subtest) were used to assess children’s skills at the pretest (before the intervention) and posttest (after the intervention). To measure retention, the same skills were also assessed for 22 children from the experimental group 3 months from the posttest (follow up). The paper discusses the results of this experimental intervention. The results show significant positive effects of the instructional program on children’s computer-based coding skills and cognitive abilities, particularly visuo-spatial skills. Between pretest and posttest, children in the experimental group improved in coding, z = 3.84, p = 0.000, r = 0.87, and in visuo-spatial skills, z = 3.09, p = 0.002, r = 0.69. The waiting list control group showed improvements in coding skills only after the intervention, at the assessment point T3, z = 2.99, p = 0.003, r = 0.71. These findings show that practice with tangible and unplugged coding during the last year of preschool not only significantly improves children’s skills to solve computer-based coding problems (near-transfer effect), but it may also have some far-transfer effects on cognitive functions, such as visuo-spatial skills.
The Relationship between Self-Esteem, Self-Efficacy, and Career Decision-Making Difficulties: Psychological Flourishing as a Mediator
Authors: Pignault Anne , Rastoder Merlin , Houssemand Claude
Published: August 2023

Well-being associated with optimism, social support, and self-esteem is positively correlated with career decision. In this perspective, a rather recent concept of flourishing as an integrative notion incorporating these different resources, positive affect, and positive experience is particularly relevant to better understand the relations and correlations between self-evaluation, well-being, and career decision-making difficulties. The present study then examines the relationship between these possible difficulties, self-esteem, self-efficacy, and flourishing. One hundred and seventy-two higher education students participated in the study and completed a four-part questionnaire with the Career Decision-Making Difficulties Questionnaire, the Flourishing Scale, the Rosenberg Self-esteem Scale, and the General Self-Efficacy Scale. The results highlight the mediation of psychological flourishing between personality dimensions—self-esteem and self-efficacy—and career decision difficulties and the fact that those who are most flourishing in their lives will also have the least difficulty in making a career decision. As for the practical implications, guidance counselors for students and young adults need to identify resources and difficulties they have to cope with. This study emphasizes the importance of guiding students in three areas: self-esteem, the perceived quality of social relations, and the meaning attributed to one’s existence. Finally, the contribution of positive psychology to career development will be discussed.
Improving the Performance of ALOHA with Internet of Things Using Reinforcement Learning
Authors: Acik Sami , Kosunalp Selahattin , Tabakcioglu Mehmet Baris , Iliev Teodor
Published: August 2023

Intelligent medium access control (MAC) protocols have been a vital solution in enhancing the performance of a variety of wireless networks. ALOHA, as the first MAC approach, inspired the development of several MAC schemes in the network domain, with the primary advantage of simplicity. In this article, we present design, implementation, and performance evaluations of the ALOHA approach, through significant improvements in attaining high channel utilization as the most important performance metric. A critical emphasis is currently focused on removing the burden of packet collisions, while satisfying requirements of energy and delay criteria. We first implement the ALOHA protocol to practically explore its performance behaviors in comparison to analytical models. We then introduce the concept of dynamic payload instead of fixed-length packets, whereby a dynamic selection of the length of each transmitted packet is employed. Another specific contribution of this paper is the integration of the transmission policy of ALOHA with the potential of Internet of Things (IoT) opportunities. The proposed policy utilizes a state-less Q-learning strategy to achieve the maximum performance efficiency. Performance outputs prove that the proposed idea ensures a maximum throughput of approximately 58%, while ALOHA is limited to nearly 18% over a single-hop scenario.
A Semi-Autonomous Multi-Vehicle Architecture for Agricultural Applications
Authors: Harik El , Guinand Frédéric , Geipel Jakob
Published: August 2023

The ageing population, climate change, and labour shortages in the agricultural sector are driving the need to reevaluate current farming practices. To address these challenges, the deployment of robot systems can help reduce environmental footprints and increase productivity. However, convincing farmers to adopt new technologies poses difficulties, considering economic viability and ease of use. In this paper, we introduce a management system based on the Robot Operating System (ROS) that integrates heterogeneous vehicles (conventional tractors and mobile robots). The goal of the proposed work is to ease the adoption of mobile robots in an agricultural context by providing to the farmer the initial tools needed to include them alongside the conventional machinery. We provide a comprehensive overview of the system’s architecture, the control laws implemented for fleet navigation within the field, the development of a user-friendly Graphical User Interface, and the charging infrastructure for the deployed vehicles. Additionally, field tests are conducted to demonstrate the effectiveness of the proposed framework.
Fixed-Time Formation Tracking Control of Multiple Unmanned Surface Vessels Considering Lumped Disturbances and Input Saturation
Authors: Sui Bowen , Zhang Jianqiang , Li Yan , Zhang Yuanyuan , Liu Zhong
Published: August 2023

This paper investigates the challenging problem of fixed-time formation trajectory tracking control for multiple unmanned surface vessels (USVs) affected by uncertain model dynamics, time-varying external ocean disturbances, as well as input saturation. Firstly, an adaptive super-twisting lumped disturbance observer (ASTLDO) is created by integrating high-order sliding mode with observer technology, which can accurately observe and compensate for the complex disturbance of the system within a finite time. Secondly, following the disturbance observer, backstepping technique, fixed-time control, and virtual leader–follower algorithm, the fixed-time formation tracking strategy is implemented. The proposed formation tracking control scheme enables the multiple surface vessels system to converge and maintain a stable desired formation in a fixed time, and the convergence time is independent of the initial states of the system. Furthermore, an adaptive auxiliary system is introduced to mitigate input saturation. In the end, the effectiveness and anti-interference ability of the suggested approach are confirmed by the formation simulation results of three USVs.
Calibration of Wideband LFM Radars Based on Sliding Window Algorithm
Authors: Kim Hyungwoo , Kim Jinwoo , Kim Jinha , Choi Jaeyoung , Hong Sangpyo , Kim Nammoon , Kim Byungkwan
Published: August 2023

This paper addresses the challenges of wideband signal beamforming in radar systems and proposes a new calibration method. Due to operating conditions, the frequency-dependent characteristics of the system can be changed, and the amplitude, phase, and time delay error can be generated. The proposed method is based on the concept of the sliding window algorithm for linear frequency modulated (LFM) signals. To calibrate the frequency-dependent errors from the transceiver and the time delay error from the true time delay elements, the proposed method utilizes the characteristic of the LFM signal. The LFM signal changes its frequency linearly with time, and the frequency domain characteristics of the hardware are presented in time. Therefore, by applying a matched filter to a part of the LFM signal, the frequency-dependent characteristics can be monitored and calibrated. The proposed method is compared with the conventional matched filter-based calibration results and verified by simulation results and beampatterns. Since the proposed method utilizes LFM signal as the calibration tone, the proposed method can be applied to any beamforming systems, not limited to LFM radars.
Harmonic Analysis of Sliding-Mode-Controlled Buck Converters Imposed by Unmodeled Dynamics of Hall Sensor
Authors: Wang Yanmin , Duan Guangxin , Yu Juan , Yue Wenjiao , Ning Jiaming , Liu Bailiang
Published: August 2023

DC–DC buck converters have become prominent components for energy optimization in power systems, and how to improve control performances is a challenging issue to be addressed. In this paper, we aim to investigate the harmonic problem of sliding mode (SM) controlled buck converters imposed by the often-ignored unmodeled dynamics of the Hall sensor. The unified mathematical model of the whole system is established by combining the SM controller, the buck converter, and the Hall sensor, where the signal loss in the transmission process of the whole closed-loop control system is considered. Based on the Lyapunov stability theorem, the SM controller is designed to guarantee system stability, as well as to deduce the stable working areas and the tuned controller parameters. Furthermore, we introduce the descriptive function (DF) approach to investigate the influence of the unmodeled dynamics of the Hall sensor on the system harmonics in the frequency domain, which can deduce the relationship between the amplitude-frequency characteristics of the output signal and the Hall sensor. Simulations and experiments validate this paper.
Phase-Change Material Thermal Energy Storage for the Smart Retrofitting of Existing Buildings
Authors: Osterman Eneja , Del Pero Claudio , Zavrl Eva , Leonforte Fabrizio , Aste Niccolò , Stritih Uroš
Published: August 2023

This article presents the use of phase-change material (PCM) thermal storage within the Horizon 2020 HEART project (Holistic Energy and Architectural Retrofit Toolkit), aimed at decarbonising the European building sector through the retrofitting of existing structures into energy-efficient smart buildings. These buildings not only reduce energy consumption, but also incorporate advanced technologies for harnessing green energy, thereby promoting environmental sustainability. The HEART project employs state-of-the-art technologies for electricity production/dispatching and heat generation/storage, managed by a cloud-based platform for the real-time monitoring of parameters and optimising energy utilisation, enabling users to control their environmental comfort. The article provides a detailed examination of one of the project’s demonstration sites in Italy, focusing on various components such as heat pumps, photovoltaic systems (PV), controllers, and particularly emphasising the significance of storage tanks. The study involved the measurement and analysis of three heat storage tanks, each with a total volume of 3000 L. These tanks utilised PCM modules for latent heat storage, significantly enhancing overall heat accumulation. Water served as the heat transfer fluid within the tanks. Through meticulous calculations, the article quantifies the accumulated heat and presents a comparative evaluation between PCM-based storage tanks and conventional water tanks, showcasing the advantages of PCM technology in terms of increased heat retention and efficiency.
PEM Fuel Cell Applications in Road Transport
Authors: Mancino Antonio , Menale Carla , Vellucci Francesco , Pasquali Manlio , Bubbico Roberto
Published: August 2023

Fuel cell electric vehicles represent a possible solution to meet the objectives of the energy transition currently underway, which sees the replacement of combustion vehicles with low environmental impact vehicles. For this reason, this market is expected to markedly grow in the coming years. Currently, the most suitable fuel cell technology for both light and heavy transport applications is the Proton Exchange Membrane fuel cell. This review provides a comprehensive description of the state of the art of fuel cell electric vehicles at different levels: vehicle configuration, fuel cell stack, and all the necessary operation systems. The current advantages and limits of the mentioned technology are highlighted, referring to recent studies aimed at optimizing the efficiency of the system and providing future perspectives.
A Solar Photovoltaic Array and Grid Source-Fed Brushless DC Motor Drive for Water-Pumping Applications
Authors: Shukla Tanmay , Nikolovski Srete
Published: August 2023

This article presents a brushless DC motor drive using a solar photovoltaic (PV) array and grid. Solar PV array-fed drive systems typically need a DC–DC converter stage in order to optimize the solar PV array-generated power utilizing a maximum power point (MPP) tracking technique. In this work, a boost DC–DC converter is used for MPP tracking purposes. This work utilizes an incremental conductance (INC) MPP-tracking algorithm. A bridgeless asymmetrical converter without a bridge rectifier is used at the grid side to improve power quality at supply mains. The presented asymmetrical converter is an amalgamation of a second order (buck boost) with a fourth-order (Cuk) converter, which lowers the net system’s order. The input inductor of the Cuk converter manages the input current profile and, thus, eradicates the need for the filter at the grid mains. The bridgeless asymmetrical converter comes with several advantages, such as rectifier removal, component reduction, and input filter elimination. The performance of the brushless DC motor is examined in this article in all three scenarios: first, when grid and solar energy are both present; second, when solar energy is the only source of energy; and third, when grid energy is the only source of energy. The dual-source-based brushless DC motor drive system has been developed on matrix-laboratory/Simulink. The results are deployed and discussed to verify the drive-system performance. The article also presents a detailed stability analysis and mathematical modeling of the presented power-quality converter and MPP tracking converter to verify different converters’ stability using a bode diagram and a pole-zero plot.
Effects of High Dietary Carbohydrate Levels on Growth Performance, Enzyme Activities, Expression of Genes Related to Liver Glucose Metabolism, and the Intestinal Microbiota of Lateolabrax maculatus Juveniles
Authors: Zheng Luzhe , Wang Zhanzhan , Zhang Bo , Yan Lulu , Wang Pengfei , Zhao Chao , Lin Heizhao , Qiu Lihua , Zhou Chuanpeng
Published: August 2023

The present study was conducted to investigate the effects of high dietary carbohydrate levels on growth performance, enzyme activities, and gene expressions related to liver glucose metabolism and the intestinal microbiota of Lateolabrax maculatus juveniles. Two experimental diets with levels of carbohydrates (20% and 30%, named the NCD group and the HCD group, respectively) were designed to feed L. maculatus (initial weight 9.45 ± 0.03 g) for 56 days. The results showed that, compared with the NCD group, the condition factor (CF) was significantly elevated in the HCD group (p < 0.05). The plasma advanced glycosylation end products (AGEs), glycated serum protein (GSP), total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and glutamate aminotransferase (AST) were significantly higher in the HCD group than those in the NCD group (p < 0.05). The intestinal lipase, chymotrypsin, and α-amylase in the HCD group were significantly higher than those in the NCD group (p < 0.05). The liver superoxide dismutase (SOD), total antioxidant capacity (T-AOC), and catalase (CAT) were significantly lower in the HCD group than in the NCD group (p < 0.05). The liver malondialdehyde (MDA) and hexokinase (HK) levels were significantly higher than those in the NCD group (p < 0.05). In the histopathological findings, liver cells in the HCD group appeared to have many vacuoles, and the number of lipid droplets increased. Compared with the NCD group, the relative expression of liver glucokinase (GK) and glycogen synthetase kinase-3 (GSK3β) genes in the HCD group was significantly increased (p < 0.05), while the relative expression of phosphoenolpyruvate carboxykinase (PEPCK) and glycogen phosphorylase (GP) genes in the HCD group was significantly reduced (p < 0.05). High-throughput 16S rRNA gene sequencing showed that high dietary carbohydrate intake changed the composition and structure of the intestinal microbiota. At the phylum level of the intestinal microbiota, high dietary carbohydrates decreased the relative abundance of Firmicutes and increased the relative abundance of Proteobacteria and Bacteroidetes. At the genus level of the intestinal microbiota, high carbohydrates decreased the relative abundance of Bacillus and increased the relative abundance of Photobacterium and Paraclostridium. From the results of this experiment on L. maculatus, high carbohydrates led to increased condition factor and liver glycogen, lipid deposition, decreased antioxidant capacity of the liver, increased relative abundance of harmful intestinal microorganisms, and disrupted glucose metabolism.
Influence of High-Intensity Ultrasound on Characteristics and Bioaccessibility of Pea Protein in Fiber-Enriched Suspensions
Authors: Kalla-Bertholdt Ann-Marie , Baier Anne Kathrin , Rauh Cornelia
Published: August 2023

Pea protein is of high interest for the food industry owing to its low allergenicity and high nutritional value. However, it often exhibits poor functionality, such as low solubility. The presence of dietary fiber in food products is beneficial for human health but may decrease the bioaccessibility of nutrients. Ultrasound, as a promising green technology, may influence properties of fibers and proteins and, thus, bioaccessibility. Therefore, this study investigated the effects of high-intensity ultrasound on the characteristics and protein bioaccessibility of protein–fiber suspensions. Suspensions containing different fiber compounds (1 wt.%) and pea protein (5 wt.%) were homogenized using high-intensity ultrasound (amplitude 116 µm, t = 150 s, energy density = 225 kJ/L, P¯ = 325 W). Owing to sonication-induced cavitation, the dispersibility of the protein was enhanced, and the viscosity of solutions containing citrus or apple fiber was increased. FE-SEM revealed the formation of different fiber–protein networks during sonication. Even if viscosity is known to have an impact on the bioaccessibility of nutrients, no restrictions on the digestibility of protein were detected during an in vitro digestion. Thus, protein uptake is probably not affected, and ultrasound can be used to modify the technofunctionality of fibers and proteins without any nutritional disadvantages.
Characterization of Volatile Flavor Compounds in Dry-Rendered Beef Fat by Different Solvent-Assisted Flavor Evaporation (SAFE) Combined with GC–MS, GC–O, and OAV
Authors: Yang Xuelian , Pei Zhaoyang , Du Wenbin , Xie Jianchun
Published: August 2023

To comprehensively understand the volatile flavor composition of dry-rendered beef fat, solvent-assisted flavor evaporation (SAFE) with four extraction solvents (dichloromethane, pentane, ethyl ether, and methanol) combined with gas chromatography–mass spectrometry (GC–MS) and gas chromatography–olfactormetry (GC–O) were performed. GC–MS analysis found 96 different volatile compounds in total using the four extraction solvents. According to the GC–MS results and the heat map and principal component analysis (PCA), most of the volatile compounds resulted from dichloromethane and pentane extraction, followed by ethyl ether. Methanol extraction found a few volatile compounds of higher polarity, which was supplementary to the analysis results. Moreover, GC–O analysis found 73 odor-active compounds in total using the four extraction solvents. The GC–O results found that pentane and dichloromethane extraction had a significantly larger number of odor-active compounds than ethyl ether and methanol extraction. This indicated that pentane and dichloromethane were more effective solvents for the extraction of odor-active compounds than the other two solvents. Finally, a total of 15 compounds of odor-active values (OAVs) ≥ 1 were determined to be the key aroma compounds in the dry-rendered beef fat, including 2–methyl–3–furanthiol, 3–methylthiopropanal, (E,E)–2,4–nonadienal, 12–methyltridecanal, and 1–octen–3–one.
The Composition of Fatty Acids in Bee Pollen, Royal Jelly, Buckthorn Oil and Their Mixtures with Pollen Preserved for Storage
Authors: Čeksterytė Violeta , Bliznikas Saulius , Jaškūnė Kristina
Published: August 2023

Honey produced by A. mellifera contains minor components present in the nectar collected from plants. Various studies of honey components and all other bee products can be informative in assessing their quality. The aim of the present study was to determine the content and composition of fatty acids (FAs) in sea buckthorn oil (SBO), royal jelly (RJ) and bee pollen (BP) and the changes in FAs content in these products during storage. The diversity of FAs and the effect of storage time on FAs content was also evaluated for the prepared-for-preservation mixtures, which included the following samples: pollen mixed with honey at a ratio of 1:2 (w/w); sample BPH, a well; BPH + 1% (w/w) SBO; and BPH + 1% (w/w) SBO + 2% (w/w) RJ. Fresh bee-collected pollen and RJ were stored at −20 °C, whereas the conserved samples were stored at +4 °C in hermetically sealed jars. The data revealed that RJ demonstrated the highest diversity of fatty acids compared to BP and BP prepared for storage with honey along with SBO and RJ. Palmitic and stearic acids were found in the highest amounts out of the eight saturated fatty acids identified in the studied SBO and RJ. The amount of these fatty acids in RJ compared to SBO was 1.27 and 6.14 times higher, respectively. In total, twenty-two unsaturated fatty acids (USFA) were identified in RJ and fourteen were found in SBO. The SBO used in this study was found to be high in linoleic acid, resulting in an increased n-6 fatty acids ratio in the prepared samples. Essential fatty acids eicosapentaenoic (EPA) and docosahexaenoic (DHA) were found in RJ, as well as in BP and BP mixed with honey. These FAs were not identified in the samples prepared with SBO even in the sample supplemented with RJ. The highest decrease in docosadienoic fatty acid was found in the BPH sample compared to BP, while arachidonic acid mostly decreased in BPH + 1% SBO compared to the BPH + 1% (w/w) SBO + 2% (w/w) RJ samples stored at +4 °C. Bee-collected pollen had the greatest influence on the number of FAs in its mixture with honey.