Improvement of Step Tracking Algorithm Used for Mobile Receiver System via Satellite

In the mobile communication via satellite, received systems are mounted on the mobile device such as ship, train, car or airplane. In order to receive continuous signals, received antenna system must be steered in both the azimuthal and elevation angle to track a satellite. This paper proposes the improved step-tracking algorithm using for mobile receiver system via satellite Vinasat I. This paper also presents the results of study, design and manufacture of the discrete-time controller system for the fast tracking of a satellite by applying an improved step tracking algorithm with fuzzy proportional integral derivative proportional integral derivative controller. Simulated and experimental results indicate that the system performances obtain from applying the improved step tracking algorithm and the fuzzy controller was better than traditional control systems

Groundwork-Based Research to Design Application SCC - Building a Sustainable Community for Children in Mountainous Area

Children’s clothing is a prime example of fast fashion, as their continuous growth requires frequent purchases. This not only impacts the environment but also puts financial strain on parents. Concurrently, many highland children lack essential material and educational resources, contributing to poverty in the region. To address these challenges, local authorities urgently require a sustainable solution that supports children, communities, and localities, fostering comprehensive development. The project development criteria are evaluated based on the United Nations’ 17 sustainable development goals (SDGs). Data was collected through an online survey of 50 married individuals, 162 non-married individuals, and interviews with those who have organized events for children in the highlands. Additionally, insights were obtained from three children from disadvantaged areas. The results indicate that all target groups show a keen interest in social activities for children. Parents facing difficulties accessing charities, and the lack of effective collaboration between charities and local authorities, hinders sustainable development efforts. Keywords: children, SDG, social sustainabilty, communit

Design of a Front-End for Satellite Receiver

This paper focuses on the design and implementation of a front-end for a Vinasat satellite receiver with auto-searching mechanism and auto-tracking satellite. The front-end consists of a C-band low-noise block down-converter and a L-band receiver. The receiver is designed to meet the requirements about wide-band, high sensitivity, large dynamic range, low noise figure. To reduce noise figure and increase bandwidth, the C-band low-noise amplifier is designed using T-type of matching network with negative feedback and the L-band LNA is designed using cascoded techniques. The local oscillator uses a voltage controlled oscillator combine phase locked loop to reduce the phase noise and select channels. The front-end has successfully been designed and fabricated with parameters: Input frequency is C-band; sensitivity is greater than -130 dBm for C-band receiver and is greater than -110dBm for L-band receiver; output signals are AM/FM demodulation, I/Q demodulation, baseband signals

Attentive Deep Neural Networks for Legal Document Retrieval

Legal text retrieval serves as a key component in a wide range of legal text processing tasks such as legal question answering, legal case entailment, and statute law retrieval. The performance of legal text retrieval depends, to a large extent, on the representation of text, both query and legal documents. Based on good representations, a legal text retrieval model can effectively match the query to its relevant documents. Because legal documents often contain long articles and only some parts are relevant to queries, it is quite a challenge for existing models to represent such documents. In this paper, we study the use of attentive neural network-based text representation for statute law document retrieval. We propose a general approach using deep neural networks with attention mechanisms. Based on it, we develop two hierarchical architectures with sparse attention to represent long sentences and articles, and we name them Attentive CNN and Paraformer. The methods are evaluated on datasets of different sizes and characteristics in English, Japanese, and Vietnamese. Experimental results show that: i) Attentive neural methods substantially outperform non-neural methods in terms of retrieval performance across datasets and languages; ii) Pretrained transformer-based models achieve better accuracy on small datasets at the cost of high computational complexity while lighter weight Attentive CNN achieves better accuracy on large datasets; and iii) Our proposed Paraformer outperforms state-of-the-art methods on COLIEE dataset, achieving the highest recall and F2 scores in the top-N retrieval task.Comment: Preprint version. The official version will be published in Artificial Intelligence and Law journa

THÀNH PHẦN HÓA HỌC VÀ HOẠT TÍNH KHÁNG VI SINH VẬT GÂY BỆNH CỦA TINH DẦU TỪ VỎ BƯỞI DA XANH (Citrus maxima (Burm.) Merr.)

Pomelo is a Vietnam’s plant species with high nutritional and economic value. Besides, pomelo essential oil contains numerous compounds with high biological activity. The essential oil is extracted by using steam distillation, and its chemical composition is determined by means of GC-MS. The major components are limonene (91.19%), b-myrcene (2.92%), a-phellandrene (1.98%), and a-pinene (1.19%). The antimicrobial activity of essential oils is tested against pathogenic Gram-positive bacteria (Bacillus cereus, Staphylococcus aureus), Gram-negative bacteria (Escherichia coli), and Aspergillus flavus at different concentrations with the agar well diffusion method. This essential oil is active against B. cereus, S. aureus, and E. coli with inhibition diameter zones at 8.3–11.3, 10.3–18.7, and 9.0–11.7 mm, respectively, and inhibits A. flavus mold with 18.9–65.0% efficiency.Bưởi là loài cây không chỉ có giá trị cao về mặt dinh dưỡng mà còn có giá trị cao về mặt kinh tế và được trồng phổ biến ở Việt Nam. Ngoài ra, tinh dầu bưởi chứa nhiều hợp chất có hoạt tính sinh học cao. Tinh dầu bưởi được chiết xuất bằng phương pháp chưng cất lôi cuốn hơi nước và thành phần hóa học được phân tích bằng phương pháp GC-MS. Thành phần chính của tinh dầu gồm limonene (91,19%), b-myrcene (2,92%), a-phellandrene (1,98%) và a-pinene (1,19%). Hoạt tính kháng vi sinh vật của tinh dầu được khảo sát với vi khuẩn Gram dương (Bacillus cereus, Staphylococcus aureus), Gram âm (Escherichia coli) và nấm mốc Aspergillus flavus ở nồng độ 5, 10, 25 và 50% bằng phương pháp khuếch tán giếng thạch. Tinh dầu có khả năng kháng B. cereus, S. aureus và E. coli với đường kính vòng kháng khuẩn lần lượt là 8,3–11,3, 10,3–18,7 và 9,0–11,7 mm và ức chế sự phát triển của A. flavus (18,9–65,0%)

Antibiotic resistance of Streptococcus pneumoniae in Vietnamese children with severe pneumonia: a cross-sectional study

BackgroundStreptococcus pneumoniae is the most common bacterium that causes community-acquired pneumonia (CAP) in children. The rate of S. pneumoniae resistance to antibiotics is increasing, particularly in patients with severe CAP. Therefore, the level of antibiotic resistance of S. pneumoniae causing severe CAP in Vietnamese children requires regular monitoring.MethodsThis was a cross-sectional descriptive study. Nasopharyngeal aspiration specimens from children were cultured, isolated, and examined for S. pneumoniae. Bacterial strains were assessed for antimicrobial susceptibility, and the minimum inhibitory concentration (MIC) was determined.ResultsEighty-nine strains of S. pneumoniae were isolated from 239 children with severe CAP. The majority of isolates were completely non-susceptible to penicillin (1.1% intermediate, 98.9% resistant) and highly resistant to erythromycin (96.6%) and clarithromycin (88.8%); the rate of resistance to ceftriaxone was 16.9%, with the proportion of intermediate resistance at 46.0%; 100% of strains were susceptible to vancomycin and linezolid. For most antibiotics, MIC50 and MIC90 were equal to the resistance threshold according to the Clinical and Laboratory Standards Institute 2021; penicillin had an eight-fold increase in MIC90 (64 mg/L) and ceftriaxone had a 1.5-fold increase in MIC90 (6 mg/L).ConclusionStreptococcus pneumoniae isolates described in this study were resistant to many antibiotics. Penicillin should not be the first-line antibiotic of choice, and ceftriaxone at an enhanced dose should be used instead

Global Evolution of Obesity Research in Children and Youths: Setting Priorities for Interventions and Policies

Background: Childhood obesity has become a major global epidemic that causes substantial social and health burdens worldwide. The effectiveness of childhood obesity control and prevention depends largely on understanding the issue, including its current development and associated factors in a contextualized perspective. Objectives: Our study aimed to gauge this kind of understanding. Methods: We systematically searched the Web of Science database for studies concerning child obesity published up to 2017 and analyzed the volume of publications, growth rates, impact scores, collaborations, authors, affiliations, and journals. A total of 57,444 research papers were included. Results: The three subject categories with the highest number of papers (over 3,000) were (1) nutrition and dietetics, (2) pediatrics, and (3) public, environmental, and occupational health. We found a dramatic increase in the amount of scientific literature on childhood obesity in the past one or two decades, led by scholars from the USA – ranking at the top regarding the total number of papers (23,965 papers; 30.8%) and total number of citations (859,793 citations) – and multiple Western countries where the obesity epidemic is prevalent. Conclusions: The findings highlight the need for improving international and local research capacities and collaboration to accelerate knowledge production and translation into contextualized and effective childhood obesity prevention

Risk factors for cannula-associated arterial thrombosis following extracorporeal membrane oxygenation support: a retrospective study

Background Hemostatic dysfunction during extracorporeal membrane oxygenation (ECMO) due to blood-circuit interaction and the consequences of shear stress imposed by flow rates lead to rapid coagulation cascade and thrombus formation in the ECMO system and blood vessels. We aimed to identify the incidence and risk factors for cannula-associated arterial thrombosis (CaAT) post-decannulation. Methods A retrospective study of patients undergoing arterial cannula removal following ECMO was performed. We evaluated the incidence of CaAT and compared the characteristics, ECMO machine parameters, cannula sizes, number of blood products transfused during ECMO, and daily hemostasis parameters in patients with and without CaAT. Multivariate analysis identified the risk factors for CaAT. Results Forty-seven patients requiring venoarterial ECMO (VA-ECMO) or hybrid methods were recruited for thrombosis screening. The median Sequential Organ Failure Assessment score was 11 (interquartile range, 8–13). CaAT occurred in 29 patients (61.7%), with thrombosis in the superficial femoral artery accounting for 51.7% of cases. The rate of limb ischemia complications in the CaAT group was 17.2%. Multivariate analysis determined that the ECMO flow rate–body surface area (BSA) ratio (100 ml/min/m2) was an independent factor for CaAT, with an odds ratio of 0.79 (95% confidence interval, 0.66–0.95; P=0.014). Conclusions We found that the incidence of CaAT was 61.7% following successful decannulation from VA-ECMO or hybrid modes, and the ECMO flow rate–BSA ratio was an independent risk factor for CaAT. We suggest screening for arterial thrombosis following VA-ECMO, and further research is needed to determine the risks and benefits of such screening