bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Sulfurization Temperature on Properties of Cu2ZnSnS4 Thin Films and Diffusion of Ti Substrate Elements
Authors: Huang Meihong , Lin Junhui , Liang Zhiyong , Chen Shaowei , Zhong Yuling , Wang Feng , Chen Bixian , Zhang Dongxia
Published: October 2024

The addition of flexible Cu2ZnSnS4 (CZTS) thin film solar cells to titanium (Ti) substrates is an attractive way to achieve the low-cost manufacturing of photovoltaics. Prior research has indicated that the appropriate diffusion of Ti elements can enhance the crystalline growth of CZTS films. However, the excessive diffusion of Ti has been shown to adversely affect the photovoltaic performance of CZTS photovoltaic devices. Therefore, it is essential to regulate the diffusion of Ti elements within CZTS thin films to optimize their photovoltaic properties. The tendency for Ti substrate elements to diffuse into CZTS films is also influenced by the activation energy associated with these Ti elements. The sulfurization temperature is posited to be a critical factor in modulating the diffusion and activation energy of Ti elements within CZTS thin films. Consequently, this research investigates the alteration of the sulfurization temperature of CZTS thin films in order to enhance the properties of these thin films and to examine the diffusion behavior of titanium elements. The results reveal that as the sulfurization temperature increases, the diffusion of Ti elements within the CZTS thin films initially increases, then decreases, and subsequently increases again. This pattern suggests that the diffusion of Ti elements is affected not only by the activation energy of the Ti elements but also by the defect hopping distance within the CZTS thin films. Notably, at a sulfurization temperature of 550 °C, the grains at the base of the CZTS thin film demonstrate an increased density, which is associated with a reduced defect hopping distance, thereby hindering the diffusion of Ti elements within the CZTS thin films. Furthermore, at this specific sulfurization temperature, the slope of the current–voltage (I–V) curve for the CZTS/Ti structure reaches its maximum, indicating optimal ohmic contact characteristics.
Microstructure and Mechanical Properties of a Weld Seam from Magnetron High-Current CO2 Welding
Authors: Miao Jun-Yan , Li Yi-Wen , Ren Bo-Wen , Zhao Hong-Lei , Zhang Si-Yu , Chang Yun-Long , Wang Qiang
Published: October 2024

External magnetic field (EMF)-assisted high-current CO2 welding is beneficial for improving the large spatter and poor performance of the welding heat-affected zone for mild steels under high-current welding specifications. In this paper, the droplet transfer behaviors were determined using a high-speed camera on a self-developed magnetically controlled CO2 welding system. Based on these welding specifications, a three-dimensional, transient, multi-energy field coupling welding system model to investigate the mechanism of the droplet and molten pool in EMF-assisted welding was developed. The microstructure and mechanical properties of the welded joint were systematically studied. The results show that the Lorentz force applied by the EMF to twist the droplet decreases the accumulated energy in the short-circuited liquid bridge and changes the liquid metal flow condition, both of which reduce the spatter by 7% but increase the welded joint hardness by 10% and tensile strength by 8%.
Uncovering Diaphragm Cramp in SIDS and Other Sudden Unexpected Deaths
Authors: Gebien Dov Jordan , Eisenhut Michael
Published: October 2024

The diaphragm is the primary muscle of respiration. Here, we disclose a fascinating patient’s perspective that led, by clinical reasoning alone, to a novel mechanism of spontaneous respiratory arrests termed diaphragm cramp-contracture (DCC). Although the 7-year-old boy survived its paroxysmal nocturnal “bearhug pain apnea” episodes, essentially by breathing out to breathe in, DCC could cause sudden unexpected deaths in children, especially infants. Diaphragm fatigue is central to the DCC hypothesis in SIDS. Most, if not all, SIDS risk factors contribute to it, such as male sex, young infancy, rebreathing, nicotine, overheating and viral infections. A workload surge by a roll to prone position or REM-sleep inactivation of airway dilator or respiratory accessory muscles can trigger pathological diaphragm excitation (e.g., spasms, flutter, cramp). Electromyography studies in preterm infants already show that diaphragm fatigue and sudden temporary failure by transient spasms induce apneas, hypopneas and forced expirations, all leading to hypoxemic episodes. By extension, prolonged spasm as a diaphragm cramp would induce sustained apnea with severe hypoxemia and cardiac arrest if not quickly aborted. This would cause a sudden, rapid, silent death consistent with SIDS. Moreover, a unique airway obstruction could develop where the hypercontracted diaphragm resists terminal inspiratory efforts by the accessory muscles. It would disappear postmortem. SIDS autopsy evidence consistent with DCC includes disrupted myofibers and contraction band necrosis as well as signs of agonal breathing from obstruction. Screening for diaphragm injury from hypoxemia, hyperthermia, viral myositis and excitation include serum CK-MM and skeletal troponin-I. Active excitation could be visualized on ultrasound or fluoroscopy and monitored by respiratory inductive plethysmography or electromyography.
Radiation-Induced Breast Angiosarcoma—A Single-Institution Experience
Authors: Buta Marko , Santrac Nada , Zegarac Milan , Goran Merima , Jeftic Nikola , Savkovic Nevena , Raketic Jovan , Pavlovic Saska , Zivkovic Ognjen , Rankovic Aleksandar , Markovic Ivan
Published: October 2024

Introduction: Radiation-induced breast angiosarcoma (RIBAS) is a rare adverse event associated with postoperative breast irradiation. The data from the literature indicate that RIBAS occurs in less than 0.3% of patients treated with adjuvant radiotherapy for breast cancer. Given the rarity, diverse clinical presentation, poor prognosis, and lack of consensus on the management, this study aimed to present experiences of our specialized cancer center with RIBAS, in terms of the incidence, presentation, management, and outcomes. Methods: We reviewed the medical records of 10,834 breast cancer patients treated at the Institute for Oncology and Radiology of Serbia between January 2013 and June 2024 to detect patients that had breast-conserving surgery, followed by postoperative irradiation, and developed angiosarcoma in the irradiated area at least 3 years after radiotherapy, without distant metastases. The incidence, latency period, management, and treatment outcomes were analyzed. Results: A total of nine female patients with RIBAS were identified and included in this study. The median age at RIBAS diagnosis was 64 years (range: 36–68), with a median latency of 64 months (95% CI > 57) from irradiation to diagnosis. The mean tumor size was 55 mm (SD 32.78). Patients were followed for a median of 30 months (range: 7–40) after initial RIBAS surgery. Local recurrence occurred in seven patients (77.8%), with five undergoing re-do surgery with curative intent. Three patients developed distant metastases during follow-up. The median overall survival (OS) was 31 months (95% CI > 30), with a 3-year survival rate of 15.2% (95% CI 2.5–91.6%). The median local recurrence-free interval was 10 months (95% CI > 3). Median OS after RIBAS local recurrence and after breast cancer treatment was 17 months (95% CI > 15) and 108 months (95% CI > 88), respectively. Conclusions: RIBAS is a rare but increasingly prevalent adverse event associated with BC irradiation, marked by an aggressive disease course and high relapse rates. Awareness, prompt diagnosis, and a radical surgical approach with wide clear margins are critical for improving patients’ outcomes.
Baseline Choroidal Blood Flow Imbalance as a Predictive Factor for Macular Edema Recurrence Secondary to Branch Retinal Vein Occlusion
Authors: Hashimoto Ryuya , Aso Kenichiro , Yata Keisuke , Fujioka Naoki , Tanaka Kazufumi , Moriyama Serika , Hirota Asato , Kawamura Juri , Maeno Takatoshi
Published: October 2024

Background/Objectives: To evaluate the roles of choroidal blood flow (CBF) and choroidal thickness (CT) as predictors of macular edema recurrence in patients with treatment-naive non-ischemic branch retinal vein occlusion (BRVO) after intravitreal ranibizumab (IVR) injection. Methods: Sixteen eyes from sixteen patients with treatment-naive non-ischemic BRVO treated with IVR, once initially and then as needed, were included in the study. CBF and CT in the subfovea, occlusive, and non-occlusive regions were measured via laser speckle flowgraphy and enhanced depth imaging optical coherence tomography over 12 months. Results: Baseline CT was significantly greater in the occlusive region (335 ± 72.1 µm) than in the non-occlusive region (274 ± 36.7 µm, p = 0.028). CT in the occlusive region was reduced significantly after 1 week (p = 0.008), but CBF did not change significantly after IVR throughout the follow-up period (p > 0.05). The occlusive/non-occlusive region CBF ratio at baseline was significantly associated with the number of IVR injections over 12 months (mean 2.63) in patients with BRVO (p = 0.048). Conclusions: Baseline CBF imbalance in eyes with treatment-naive BRVO may indicate the recurrence of macular edema after ranibizumab therapy.
Lung Ultrasound Assessment of Regional Distribution of Pulmonary Edema and Atelectasis in Infants with Evolving Bronchopulmonary Dysplasia
Authors: Patel Jimikumar , Weinberger Barry , Pulju Margaret , Galanti Stephanie G. , Kasniya Gangajal , Gupta Venkata , Kurepa Dalibor
Published: October 2024

Background: Preterm infants are at risk for bronchopulmonary dysplasia (BPD) due to prolonged respiratory support. Studies have described differences in the regional distribution of lung ventilation (non-dependent (NDL) vs. dependent (DL)). The aim of this study was to use LUS to compare regional distribution of pulmonary edema and atelectasis in infants with evolving BPD. Methods: We prospectively performed LUS in premature infants with evolving BPD. On each side, three lung areas (NDL/anterior, lateral, and DL/posterior) were examined for the presence of pulmonary edema and atelectasis. Pulmonary edema scores were assigned based on the number of B-lines, and atelectasis scores were assigned based on the presence/absence of atelectasis. Results: 38 premature infants were enrolled. The NDL showed more pulmonary edema and atelectasis compared to the DL (p = 0.003, p = 0.049, respectively) and compared to the lateral lung (p =< 0.001, p = 0.004, respectively). There was no difference between the lateral and DL (p = 0.188, p = 0.156, respectively). There was no difference between the right and the left lung (p = 0.223, p = 0.656, respectively). Conclusions: In this cohort of preterm infants with evolving BPD, lung disease was unevenly distributed, with more pulmonary edema and atelectasis in the NDL regions compared to the DL or lateral regions.
The Influence of Wind Musical Instruments on the Orofacial System
Authors: Hernández Raquel Laparra , Arias-Luxán Santiago , Sauro Salvatore , Lanuza Alicia
Published: October 2024

Objectives: The main objective of this study was to assess whether there are differences in the muscular and occlusal levels between wind players and the general population, in addition to assessing the different repercussions depending on the embouchure type. Material and Methods: Two cohorts were chosen: one of them comprised intermediate students related to the practice of a wind instrument (n = 39), and the other one, harmonized with the former, comprised secondary students that served as a control group (n = 19). Overjet, overbite, presence of lip abrasion and/or erosion, Angle’s molar class, Little’s irregularity index, dental abrasion, presence of labial herpes, presence of tooth sensitivity, and presence of articular noises muscle pain were evaluated. Results: Significant statistical differences between the groups were found regarding overjet, overcrowding of teeth, lower lip erosion, and dental abrasion, which was higher in musicians. Lastly, within the group of musicians, it was proven that tooth sensitivity was higher in the group of brass musicians. Conclusions: Wind instrument practice may be a risk factor for developing some orofacial involvement, and there are no differences among the various existing mouthpieces.
Candidemia in Pediatric-Clinic: Frequency of Occurrence, Candida Species, Antifungal Susceptibilities, and Effects on Mortality (2020–2024)
Authors: Şanlı Kamuran , Arslantaş Esra , Ceylan Ayşe Nur , Öncel Beyza , Özkorucu Duygu , Özkan Karagenç Ayşe
Published: October 2024

Objective: Invasive candidiasis is defined as an important infection that increases the duration of patients’ hospital stay, costs, mortality and morbidity. In this study, we aimed to investigate the frequency of candidiasis in blood cultures of pediatric hematology patients, Candida species, antifungal susceptibilities, and their effects on mortality. Materials and Methods: Patients with Candida growth in their blood cultures at follow-up in the pediatric hematology clinic of our hospital between 2020 and 2024 were included in the study. Age, gender, primary diseases and risk levels, subtypes and antifungal susceptibilities of Candida grown in blood cultures, the presence of neutropenia in patients, the antifungals used for prophylaxis and treatment, the duration of infection, other bacteria grown additionally during the fungal infection period, the local infection source and the patients’ discharge status were obtained from medical records. These constituted the study data. Results: Blood cultures were requested for 594 patients from the Pediatric hematology Clinic, and Candida was grown in only 37 (6.7%) of them. A total of 43.2% of them were the Candida parapsilosis complex, 29.7% were Candida albicans and 8.1% were the Candida haemulonii complex. Antifungal susceptibilities were over 90% for anidulafungin, micafungin, caspofungin, posaconazole, itraconazole and amphotericin B, followed by 86.7% for fluconazole and 84.4% for voriconazole. The mean age of the patient group was 6.8 years, 50.5% of whom were female and 40.5% of whom were male. The Candida infections developed on the 12.1th day of the neutropenia process on average. The mean invasive Candida infection period was 7 days. A total of 18.9% had a second bacterial infection and 13.5% had a local infection. A total of 51.4% had a single antifungal, 18.9% had two antifungals and 2.1% had more than two antifungals. A total of 35.1% of the patients with invasive candidiasis died. The primary diagnosis of the disease, Patient risk level, and the female gender were important factors affetting mortality. Conclusions: In a pediatric hematology clinic, the non-albicans group in invasive candidiasis infections was notable, with the C. parapsilosis complex occurring most frequently. There was still a high sensitivity to echinocandin antifungals and a decreased sensitivity to triazoles. It was found that the factor of the clinical diagnosis, being in the high-risk group and being female had significant effects on the survival rate of patients with candidiasis infections.
Characteristics of Hepatocellular Carcinoma by Sex in Mexico: A Multi-Institutional Collaboration
Authors: Melchor-Ruan Javier , Santiago-Ruiz Luis , Murillo-Ortiz Blanca Olivia , Rivera-Rivera Samuel , Leal-Herrera Yelda A. , Suárez-García David , Remes-Troche José María , Grube Peter , Martínez-Mier Gustavo , Ruiz-García Erika , Ramos-Mayo Alan , Velarde-Ruiz-Velasco José Antonio , Gamboa-Gutierrez Ricardo , Ordoñez-Escalante Karla Gabriela , Cisneros-Garza Laura Esthela , Leal-Leyte Pilar , Sepúlveda-Delgado Jesús , González-Huezo María Saraí , Arvizu-Castillo Ricardo , Urías-Rocha Jorge , Flores-de-la-Torre Celia Beatriz , Carrillo-Mendoza Leonardo Manuel , Gámez-del-Castillo Juan Manuel , Lajous Martín , Monge Adriana , Zamora-Valdés Daniel
Published: October 2024

Liver cancer is the fourth leading cause of cancer-related death worldwide. In Mexico, there is a high burden of liver cancer mortality in rural states, affecting both women and men equally. Thus, we aimed to describe the demographic and clinical characteristics of hepatocellular cancer (HCC) by sex in Mexico. Demographic and clinical information was extracted retrospectively from the medical records of patients with HCC initially treated (2015–2022) at institutions participating in a national survey across the country. The male-to-female ratio was calculated at the national and regional levels, and the results were stratified by sex. Among 697 HCC patients, the age at diagnosis was 65.4 ± 11.9 years and 20% were diagnosed at ≥75 years. The male-to-female ratio was 1.4:1, ranging from 1:1 in the northwestern and southwestern regions, to 2.1:1 in the western region. The proportion of cirrhosis was similar between the sexes; however, the etiology of cirrhosis differed: cryptogenic cirrhosis was higher in women and alcohol consumption was higher in men. Men had a higher proportion of advanced HCC, poor/undifferentiated tumors, and ≥4 nodules than women. HCC in the Mexican population affects both men and women at a 1.4:1 male-to-female ratio. This unique proportion by sex could be explained by the differences in the prevalence of risk factors across our heterogeneous country.
Apixaban-Induced Esophagitis Dissecans Superficialis-Case Report and Literature Review
Authors: Coseru Alexandru Ionut , Ciortescu Irina , Nemteanu Roxana , Barboi Oana-Bogdana , Floria Diana-Elena , Vulpoi Radu-Alexandru , Strungariu Diana Georgiana , Ilie Sorina Iuliana , Rosca Vadim , Drug Vasile-Liviu , Plesa Alina
Published: October 2024

Novel direct oral anticoagulants (DOACs) are prescribed worldwide in the treatment of non-valvular atrial fibrillation. Adverse reactions have been reported following the use of DOACs. One notable trend in the literature is the growing number of reported cases of esophagitis dissecans superficialis (EDS) generated by DOAC use. We hereby report the case of a 73-year-old woman who presented to the hospital with asthenia, dysphagia, and melena two days prior to admission. The patient had taken apixaban due to non-valvular paroxysmal atrial fibrillation for a few weeks. The biological panel showed moderate anemia with a hemoglobin level of 7.7 g/dL Apixaban-induced EDS was diagnosed by the characteristic endoscopic findings. The patient received treatment with a proton pump inhibitor (pantoprazole) in a double dose. Also, an iron treatment was recommended for a period of six months. The follow-up endoscopy at one month confirmed the healing of the esophageal lesions. The case was discussed with the cardiologist. The first anticoagulant treatment proposed after discharge was a vitamin K antagonist (acenocumarol) but the patient refused this medication and thus it was decided to initiate rivaroxaban. Although DOACs have demonstrated their efficacy in the prevention and treatment of stroke and thromboembolism among the aging demographic, cases of DOAC-induced EDS will continue to pose numerous challenges for physicians worldwide.
Air Route Design of Multi-Rotor UAVs for Urban Air Mobility
Authors: Li Shan , Zhang Honghai , Li Zhuolun , Liu Hao
Published: October 2024

UAVs will present significant air traffic in the urban airspace in the future, which brings new challenges to urban air traffic management and control. This paper presents an air route design scheme for multi-rotor UAVs in urban airspace to enable UAV operations at orderly levels. The air routes include legs and intersections, which are the three-dimensional channels of UAV flight. Based on the concept of structured and layered urban airspace, the cylindrical pipeline flight leg is designed, and the operation concept, characteristic parameters and flight procedures of along-road and roundabout intersections are proposed. By defining UAV conflict risk and intersection service level metrics, the operation situation of UAVs is quantitatively evaluated. Taking an urban transportation scenario as a case, the proposed route design scheme is simulated in different scale UAV operating scenarios. The results show that the number of UAVs at the intersection is positively correlated with the conflict probability, the number of crossing routes is negatively correlated with the intersection passing rate, and the UAV arrival rate is positively correlated with the intersection average passing time. The along-road type intersection is suitable for the area with fewer crossing routes and sparse UAVs, while the roundabout type intersection is adapted for the area with more crossing routes and dense UAVs. This research provides a new idea for urban UAV air route design, which is helpful in promoting the standardized management of UAVs and accelerating the integration of UAVs into urban airspace.
MPC-Based Dynamic Trajectory Spoofing for UAVs
Authors: Hou Bo , Yin Zhongjie , Jin Xiaolong , Fan Zhiliang , Wang Haiyang
Published: October 2024

Navigation spoofing has been widely utilized in unmanned aircraft vehicle (UAV) countermeasures, due to its advantages of covertness, effectiveness, and dynamic trajectory control ability. However, existing research faces two primary challenges. Firstly, sudden changes in the target UAV’s trajectory can result in a significant degradation in the spoofing performance, which may enable the onboard inertial components to detect and identify the ongoing spoofing attempts. Secondly, gradual accumulation of control errors over time degenerates the spoofing effect. To address these problems, we propose a dynamic trajectory spoofing approach for UAVs based on model predictive control (MPC), which progressively steers the UAVs towards the predetermined trajectory of the spoofer. Simulation results demonstrate a substantial enhancement in dynamic trajectory control performance and decrease in accumulation error compared to the existing methods.
A Structural Vector Autoregression Exploration of South Africa’s Monetary and Macroprudential Policy Interactions
Authors: Magubane Khwazi , Nzimande Ntokozo Patrick
Published: October 2024

Interactions between monetary and macroprudential policy are crucial in safeguarding price and financial stability. This study investigates the macroeconomic and financial impacts of monetary and macroprudential policy interactions in South Africa, a leading African economy in developing macroprudential frameworks. The existing literature largely focuses on the effectiveness of these policies independently, leaving a gap in understanding how their interaction affects their overall efficacy. Employing a Structural Vector Autoregression (SVAR) model and utilizing data from 1980 to 2023, this study uniquely incorporates the financial cycle to represent financial developments. The results reveal significant effects of both policies on key variables such as output, the financial cycle, and the price level. Specifically, policy contractions reduce output and the financial cycle but increase the price level, illustrating the ‘price puzzle’. This study further identifies an endogenous response between the two policies: monetary policy reacts by rising to reduce price levels following a macroprudential shock, while macroprudential policy rises to stimulate financial activity after a monetary shock. These findings underscore the importance of using both policies in conjunction but in opposite directions to balance their effects and achieve price and financial stability. This study suggests that an optimal combination of monetary and macroprudential policies is critical for maintaining macroeconomic equilibrium.
Introductory Physics Students Who Typically Worked Alone or in Groups: Insights from Gender-Based Analysis Before and During COVID-19
Authors: Ghimire Apekshya , Singh Chandralekha
Published: October 2024

Collaboration with peers both inside and outside the classroom can be an invaluable tool for helping students learn physics. We investigated the impact of peer collaboration on learning physics by examining the characteristics of women and men who typically worked alone versus those who typically collaborated with peers in their algebra-based introductory physics course when they took the course before and during the COVID-19 pandemic when the classes were on Zoom. Our findings indicate that, on average, students who worked with peers had higher grades and reported greater peer influence on their physics self-efficacy during the pandemic compared to those who worked alone. We also observed that, for both women and men, a larger percentage of students typically worked in groups before the pandemic, while a greater percentage typically worked alone during the pandemic. We discuss these results in relation to students’ prior academic preparation, physics grades, self-efficacy and their perception of the effectiveness of peer collaboration on their physics self-efficacy.
Analysis of Tactical Knowledge for Learning an Alternative Invasion Sport
Authors: Calle Olga , Antúnez Antonio , Ibáñez Sergio José , Feu Sebastián
Published: October 2024

The study of declarative and procedural knowledge in sport allows us to assess students’ tactical learning processes. The aim of this study was to analyze and compare the level of declarative and procedural knowledge acquired by students according to the pedagogical model and gender, after the application of two intervention programs for an alternative invasion sport, “Rosquilla”. This study involved 136 students distributed into six groups of Primary Education (fifth and sixth year) and Secondary Education (first year). Each group in the same year participated in a different intervention program, one based on the Game-Centered Model and the other on a hybrid model of the Game-Centered Model and the Sports Education Model. A descriptive analysis was carried out to determine the characteristics of the participants. Subsequently, an independent samples Mann–Whitney U-test was applied to compare the level of knowledge between the models and genders in the pre- and post-test periods. A Linear Mixed Model was used to analyze the level of knowledge of students within each group and compare them according to methodology and gender. The results indicate that both programs generated improvements in declarative and procedural knowledge. Therefore, students learn equally regardless of the methodological perspective and gender.
Science and Mathematics Teachers’ Integration of TPACK in STEM Subjects in Qatar: A Structural Equation Modeling Study
Authors: Mansour Nasser , Said Ziad , Çevik Mustafa , Abu-Tineh Abdullah
Published: October 2024

This study aimed to explore how secondary school science and mathematics teachers in Qatar integrate Technological Pedagogical Content Knowledge (TPACK) into their teaching practices. The study examined the relationships between the subcomponents of TPACK using structural equation modeling (SEM), complemented by an analysis of additional categorical variables. A total of 245 science and mathematics teachers from Qatar participated in the research. The model’s findings showed that the internal components—technological knowledge, pedagogical knowledge, and content knowledge—had a significant and positive direct effect on the external factors: technological pedagogical knowledge, technological content knowledge, and pedagogical content knowledge. However, these internal components did not directly impact TPACK itself. Together, these variables accounted for 77% of the variance in TPACK. Among the findings, Technological Content Knowledge (TCK) emerged as one of the most influential variables affecting TPACK, emphasizing its importance in teachers’ TPACK integration. On the other hand, it was found that Pedagogical Content Knowledge (PCK) did not have a direct and significant effect on TPACK. Categorical variables like certificates and postgraduate education significantly impact TPACK and its subcomponents, while gender, field of study, and teaching experience do not. This finding underscores the importance of structured training and postgraduate education in enhancing TPACK skills for science and mathematics teachers. Participation in technology-based certification programs and postgraduate studies in STEM is crucial for their TPACK development in teaching STEM subjects. Future studies could explore the long-term impact of structured, technology-based training programs on enhancing STEM teachers’ TPACK development and assess how this improvement influences student learning outcomes in science and mathematics classrooms. This would provide deeper insights into the effectiveness of such programs and their potential to transform teaching practices and student achievement in STEM education.
Calculation of Distribution Network PV Hosting Capacity Considering Source–Load Uncertainty and Active Management
Authors: Lin Tingting , Wu Guilian , Lai Sudan , Hu Hao , Hu Zhijian
Published: October 2024

The access of a high proportion of photovoltaic (PV) will change the energy structure of the distribution network (DN), resulting in a series of safety operation risks. This paper proposes a two-stage PV hosting capacity (PVHC) calculation model to assess the maximum PVHC, considering the uncertainty and active management (AM). Firstly, we employ a robust optimization model to characterize the uncertainty of sources and loads in DN with PV and analyze the worst-case scenarios for PVHC. Subsequently, we construct a PVHC calculation model that takes into account AM, and convert the model into a mixed-integer second-order cone (MISOC) model using linearization techniques. Finally, we apply “heuristic optimization + CPLEX solver” to solve the model and introduce overvoltage and overcurrent indices to analyze the safety of the DN under PV limit access. Case studies are carried out on the IEEE 33-bus system and a practical case. Results show that (1) only the uncertainty that reduces the load or increases the output efficiency will affect PVHC; (2) for DN limited by overvoltage, AM can better improve PVHC; however, for DN limited by maximum transmission power, the effect of AM is low; (3) for most DN, SVC can improve PVHC, but the effect is modest. And network reconfiguration can significantly increase PVHC on the system with poor branch network, even reaching 150% of the original PVHC.
Content-Adaptive Bitrate Ladder Estimation in High-Efficiency Video Coding Utilizing Spatiotemporal Resolutions
Authors: Šuljug Jelena , Rimac-Drlje Snježana
Published: October 2024

The constant increase in multimedia Internet traffic in the form of video streaming requires new solutions for efficient video coding to save bandwidth and network resources. HTTP adaptive streaming (HAS), the most widely used solution for video streaming, allows the client to adaptively select the bitrate according to the transmission conditions. For this purpose, multiple presentations of the same video content are generated on the video server, which contains video sequences encoded at different bitrates with resolution adjustment to achieve the best Quality of Experience (QoE). This set of bitrate–resolution pairs is called a bitrate ladder. In addition to the traditional one-size-fits-all scheme for the bitrate ladder, context-aware solutions have recently been proposed that enable optimum bitrate–resolution pairs for video sequences of different complexity. However, these solutions use only spatial resolution for optimization, while the selection of the optimal combination of spatial and temporal resolution for a given bitrate has not been sufficiently investigated. This paper proposes bit-ladder optimization considering spatiotemporal features of video sequences and usage of optimal spatial and temporal resolution related to video content complexity. Optimization along two dimensions of resolution significantly increases the complexity of the problem and the approach of intensive encoding for all spatial and temporal resolutions in a wide range of bitrates, for each video sequence, is not feasible in real time. In order to reduce the level of complexity, we propose a data augmentation using a neural network (NN)-based model. To train the NN model, we used seven video sequences of different content complexity, encoded with the HEVC encoder at five different spatial resolutions (SR) up to 4K. Also, all video sequences were encoded using four frame rates up to 120 fps, presenting different temporal resolutions (TR). The Structural Similarity Index Measure (SSIM) is used as an objective video quality metric. After data augmentation, we propose NN models that estimate optimal TR and bitrate values as switching points to a higher SR. These results can be further used as input parameters for the bitrate ladder construction for video sequences of a certain complexity.
Experimental Study on Human Kinetic Energy Harvesting with Wearable Lifejackets to Assist Search and Rescue
Authors: To Jeffrey , Huang Loulin
Published: October 2024

This study explores the integration of a human kinetic energy-harvesting mechanism into lifejackets to address the energy needs of aid search and rescue operations in aquatic environments. Due to the limited data on the movement patterns of drowning individuals, a human motion model has been developed to identify optimal design parameters for energy harvesting. This model is developed from computer vision analysis of underwater footage and motion capture laboratory experiments and is used to quantify the potential for power generation. The field testing experiment is conducted underwater, replicating the environment used for footage collection and analysis for the modelling. During the field testing, the participant wears a lifejacket integrated with the energy-harvesting device. Field testing data are then collected to verify the model. The efficacy of this approach is demonstrated with observed power outputs ranging from 0 mW to 754 mW in simulations and experiments. Despite challenges such as the “dead zone” in a drowning person’s motion, the success of the experiments underscores the potential of the proposed energy-harvesting mechanism to efficiently harness the kinetic energy generated by a drowning person’s movements. This study contributes to the development of sustainable, energy-efficient solutions for search and rescue operations, particularly in remote and challenging aquatic environments.
Decoupling Online Ride-Hailing Services: A Privacy Protection Scheme Based on Decentralized Identity
Authors: Sun Nigang , Liu Yuxuan , Zhang Yuanyi , Liu Yining
Published: October 2024

Online ride-hailing services have become a vital component of urban transportation worldwide due to their convenience and flexibility. However, the expansion of their user base has dramatically heightened the risks of user privacy information leakage. Among these risks, the privacy leakage problem caused by the direct correlation between user (driver and passenger) identity information and location-based ride information is of particular concern. This paper proposes a novel privacy protection scheme for ride-hailing services. In this scheme, decentralized identities are employed for user authentication, separating the identity registration service from the ride-hailing platform, thereby preventing the platform from obtaining user privacy data. The scheme also employs a fuzzy matching strategy based on location Points of Interest (POI) and a ciphertext-policy attribute-based hybrid encryption algorithm to hide the user’s precise location and restrict access to location information. Crucially, the scheme achieves the complete decoupling of identity registration services and location-based ride services on the ride-hailing platform, ensuring that users’ real identities and ride data cannot be directly associated, effectively protecting user privacy. Within the decoupled architecture, regulatory authorities are established to handle emergencies within ride-hailing services. Through simulation experiments and security analysis, this scheme is demonstrated to be both feasible and practical, providing a new privacy protection solution for the ride-hailing industry.
Unsupervised Security Threats Identification for Heterogeneous Events
Authors: Jang Young In , Choi Seungoh , Min Byung-Gil , Choi Young-June
Published: October 2024

As cyberattacks targeting industrial control systems continue to evolve, the development of sophisticated technologies to detect these security threats becomes increasingly essential. In addition, it is necessary to update adversarial information constantly. However, this process is complicated by the deployment of heterogeneous equipment, which increases the number of indicators and characteristics that must be analyzed by security administrators. Furthermore, security operation centers often struggle to respond promptly to adversaries because of the high number of false alerts caused by unreliable system labels. These challenges make it difficult to construct reliable detection systems. To address these issues, we propose a robust unsupervised threat-identification method. Our approach involves applying a preprocessing technique tailored to the various data types pertinent to alerts, followed by classifying unlabeled alerts using an autoencoder (AE) model. Despite the presence of numerous false positives, we verified that the proposed model could effectively distinguish between different attack types and identify their relationships with only one round of training in homogeneous and heterogeneous environments within industrial control systems. Moreover, our model can filter and display data classified as actual attacks and generate relational tables.
ESFuse: Weak Edge Structure Perception Network for Infrared and Visible Image Fusion
Authors: Liu Wuyang , Tan Haishu , Cheng Xiaoqi , Li Xiaosong
Published: October 2024

Infrared and visible image fusion (IVIF) fully integrates the complementary features of different modal images, and the fused image provides a more comprehensive and objective interpretation of the scene compared to each source image, thus attracting extensive attention in the field of computer vision in recent years. However, current fusion methods usually center their attention on the extraction of prominent features, falling short of adequately safeguarding subtle and diminutive structures. To address this problem, we propose an end-to-end unsupervised IVIF method (ESFuse), which effectively enhances fine edges and small structures. In particular, we introduce a two-branch head interpreter to extract features from source images of different modalities. Subsequently, these features are fed into the edge refinement module with the detail injection module (DIM) to obtain the edge detection results of the source image, improving the network’s ability to capture and retain complex details as well as global information. Finally, we implemented a multiscale feature reconstruction module to obtain the final fusion results by combining the output of the DIM with the output of the head interpreter. Extensive IVIF fusion experiments on existing publicly available datasets show that the proposed ESFuse outperforms the state-of-the-art(SOTA) methods in both subjective vision and objective evaluation, and our fusion results perform well in semantic segmentation, target detection, pose estimation and depth estimation tasks. The source code has been availabled.
Research on a Feature Point Detection Algorithm for Weld Images Based on Deep Learning
Authors: Kang Shaopeng , Qiang Hongbin , Yang Jing , Liu Kailei , Qian Wenbin , Li Wenpeng , Pan Yanfei
Published: October 2024

Laser vision seam tracking enhances robotic welding by enabling external information acquisition, thus improving the overall intelligence of the welding process. However, camera images captured during welding often suffer from distortion due to strong noises, including arcs, splashes, and smoke, which adversely affect the accuracy and robustness of feature point detection. To mitigate these issues, we propose a feature point extraction algorithm tailored for weld images, utilizing an improved Deeplabv3+ semantic segmentation network combined with EfficientDet. By replacing Deeplabv3+’s backbone with MobileNetV2, we enhance prediction efficiency. The DenseASPP structure and attention mechanism are implemented to focus on laser stripe edge extraction, resulting in cleaner laser stripe images and minimizing noise interference. Subsequently, EfficientDet extracts feature point positions from these cleaned images. Experimental results demonstrate that, across four typical weld types, the average feature point extraction error is maintained below 1 pixel, with over 99% of errors falling below 3 pixels, indicating both high detection accuracy and reliability.
Method for Noise Reduction by Averaging the Filtering Results on Circular Displacements Using Wavelet Transform and Local Binary Pattern
Authors: Ciotirnae Petrica , Dumitrescu Catalin , Chiva Ionut Cosmin , Semenescu Augustin , Popovici Eduard Cristian , Dranga Diana
Published: October 2024

Algorithms for noise reduction that use the translation invariant wavelet transform indirectly are spatially selective filtering algorithms in the wavelet domain. These algorithms use the undecimated wavelet transform to accurately determine the coefficients corresponding to the contours in the images, these being processed differently from the other wavelet coefficients. The use of the undecimated wavelet transform in image noise reduction applications leads not only to an improvement in terms of Mean Square Error (MSE), but also in terms of the content quality of the processed images. In the case of noise reduction procedures by truncation of wavelet coefficients, artifacts appear, especially in the approximation of singularities, due to some pseudo-Gibbs phenomena. These artifacts, which appear locally, are troublesome in the case of object recognition applications from images acquired in conditions of nonuniform illumination and low contrast. In this work we propose a method of feature extractor based on undecimated wavelet transform (UWT) and local binary pattern (LBP). The results obtained on images acquired from drones in adverse conditions show promising results in terms of accuracy. The authors show that the displacement-invariant wavelet transform is an very good method of compression and noise reduction in signals.
A Novel Day-Ahead Optimization-Oriented Low-Carbon Economic Scheduling Scheme for Integrated Energy Systems
Authors: Liang Youdong , Li Peng , Yu Zhiran , Yin Zhilong , Yu Feng , Wang Zhiguo
Published: October 2024

As the global energy structure undergoes transformation and the low-carbon development process continues to advance, integrated energy systems have progressively emerged as crucial technical support for achieving sustainable development. In this paper, a joint-day optimal scheduling model is put forward considering the existence of dispatchable resources in community integrated energy systems (CIES). The aim is to cut down the system operation cost and enhance energy utilization efficiency. This model is founded on the concept of energy hubs and combines the shiftable, transferable, and reducible characteristics of demand-side flexible loads. It includes gas turbine power generation systems, energy storage, as well as wind and solar renewable resources. System operation cost and carbon trading cost are comprehensively taken into account, and ultimately, the CIES low-carbon economic dispatch model with the lowest total cost as the optimization objective is established. The Yalmip toolbox and Cplex solver are employed to solve the model. The optimization results of flexible electric and thermal loads participating in dispatching under different scenarios are analyzed through simulation. The economic benefits of electric and thermal independent dispatching are compared and analyzed, and the economic benefits of electric and thermal coupled dispatching are verified. The study reveals that the rational scheduling of user-side flexible loads can notably reduce operating costs, lower the load peak-to-valley difference and carbon emissions, and boost the comprehensive economic and environmental benefits of the system.
On the System-Level Design of Noise-Shaping SAR Analog-to-Digital Converters
Authors: Ismail Ayman H.
Published: October 2024

In this work, the system-level design of noise-shaping (NS) successive-approximation (SAR) analog-to-digital converters (ADCs) is investigated and analyzed. It is shown that despite the fact that the NS SAR architecture shares the same fundamental NS principle with the ΣΔ architecture, there are a few implementation differences that imply different considerations for optimum system-level design, particularly in the selection of the system oversampling ratio (OSR) and consequent resolution of the associated digital-to-analog converter (DAC) for a certain target overall resolution. In addition, the impacts of the OSR value on the power dissipation and figure-of-merit (FOM) are addressed in details.
Dual-Band Low-Noise Amplifier for GNSS Applications
Authors: Pietron Daniel , Borejko Tomasz , Pleskacz Witold Adam
Published: October 2024

A new dual-band low-noise amplifier (LNA) operating at L1/E1 1.575 GHz and L5/E5 1.192 GHz center frequencies for global navigation satellite system receivers is proposed. A doubled common-source amplifier architecture is used with a single input, shared gate inductor, and two outputs to split the RF signal into separate RX channels. The main advantage of the proposed circuit is compatibility with widespread multi-band antennas with single RF connectors dedicated to high-precision applications, as well as the possibility to use cheap SAW filters with small footprints to build low-cost, highly accurate GNSS receiver modules. The input and both outputs are well matched to 50 Ω impedance. The LNA is designed with a 110 nm CMOS process, consuming 6.13 mA current from a 1.5 V supply. The measured noise figures and voltage gains of the dual-band LNA are, respectively, NF1/NF5 = 3.23/3.5 dB and G1/G5 = 21.22/18.2 dB in the band of interest for each channel. The measured impedance matching at the input (S11) and output (S22) of the dual-band low-frequency amplifier is as follows: S11_L1 = −23.89, S11_L5 = −8.42, S22_L1 = −12.65, S22_L5 = −15.08. The one-decibel compression points are L1 band PdB1 = −37.71 dBm and L5 band PdB5 = −34.72 dBm, respectively.