Digital resampling and timing recovery in QAM systems

Digital resampling is a process that converts a digital signal from one sampling rate to another. This process is performed by means of interpolating between the input samples to produce output samples at an output sampling rate. The digital interpolation process is accomplished with an interpolation filter. The problem of resampling digital signals at an output sampling rate that is incommensurate with the input sampling rate is the first topic of this thesis. This problem is often encountered in practice, for example in multiplexing video signals from different sources for the purpose of distribution. There are basically two approaches to resample the signals. Both approaches are thoroughly described and practical circuits for hardware implementation are provided. A comparison of the two circuits shows that one circuit requires a division to compute the new sampling times. This time scaling operation adds complexity to the implementation with no performance advantage over the other circuit, and makes the 'division free' circuit the preferred one for resampling. The second topic of this thesis is performance analysis of interpolation filters for Quadrature Amplitude Modulation (QAM) signals in the context of timing recovery. The performance criterion of interest is Modulation Error Ratio (MER), which is considered to be a very useful indicator of the quality of modulated signals in QAM systems. The methodology of digital resampling in hardware is employed to describe timing recovery circuits and propose an approach to evaluate the performance of interpolation filters. A MER performance analysis circuit is then devised. The circuit is simulated with MATLAB/Simulink as well as implemented in Field Programmable Gate Array (FPGA). Excellent agreement between results obtained from simulation and hardware implementation proves the validity of the methodology and practical application of the research works

Study on association between SLC2A9 rs3733591 and Gout susceptibility in 481 Vietnamese individuals

Gout is a common form of inflammatory arthritis that is strongly associated with elevated uric acid concentration in the blood. The development of the disease is not only triggered by environmental factors but also genetic variations. Previous studies demonstrated that the genetic associations with gout vary in different populations in the world. This study aimed to identify the relationship between SLC2A9 rs3733591 and gout susceptibility in the Vietnamese population. Total DNAs were extracted from 481 blood samples including 160 patients with gout and 321 age-matched healthy controls. The genotyping of SLC2A9 rs3733591 was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Chi-squared test was used to test whether the genotypes frequencies of rs3733591 follow Hardy-Weinberg equilibrium (HWE) and to check its association with gout in three models (additive, recessive, dominant) and allele form. The result showed that SLC2A9 rs3733591 was in agreement with Hardy-Weinberg equilibrium (p>0.05). However, there was no association between the rs3733591 and gout in any tested models (p>0.05). This study will contribute to the genetic study of gout susceptibility in Vietnam

The influence of economic factors on the sustainable energy consumption: evidence from China

Recently, sustainable energy consumption has been a significant factor in reducing environmental degradation due to the high economic growth, and this phenomenon demands more attention of scholars and policymakers. Thus, the current literature examines the impact of economic factors such as economic growth, foreign direct investment (FDI), inflation, and population growth on sustainable energy consumption (SEC), particularly in renewable energy consumption (REC) in China. This study used secondary data collection methods extracted from world development indicators (WDI), incorporating stationary tests like Phillips-Perron (PP) and Augmented Dickey-Fuller (ADF) to check the unit root of the constructs. The time-series data involved are from 1981 to 2019. The autoregressive distributed lag (ARDL) model was utilized to examine the association among the variables. The results indicated that economic growth, FDI, inflation, and population growth were positively associated with SEC in China. This study provides the guidelines to the policymakers to develop policies related to the SEC

Design of Mobile Manipulator for Fire Extinguisher Testing. Part I Key Specifications and Conceptual Design

All flames are extinguished as early as possible, or fire services have to deal with major conflagrations. This leads to the fact that the quality of fire extinguishers has become a very sensitive and important issue in firefighting. Inspired by the development of automatic fire fighting systems, this paper proposes key specifications based on the standard of fire extinguishers that is ISO 7165:2009 and ISO 11601:2008, and feasible solutions to design a mobile manipulator for automatically evaluating the quality or, more specifically, power of fire extinguishers. In addition, a part of the mechanical design is also discussed.Comment: 10 pages, 8 figures, the 7th International Conference on Advanced Engineering, Theory and Application

Transoral endoscopic thyroidectomy vestibular approach as a novel technique for pediatric populations: Results from a single surgeon

BackgroundThe transoral endoscopic thyroidectomy vestibular approach (TOETVA) is increasingly being adopted worldwide because of its many advantages. However, there are few reports on the effectiveness and safety of TOETVA in children. In this study, we report the results of the application of TOETVA on 27 pediatric patients in Vietnam. To the best of our knowledge, this is also the largest sample size of the TOETVA technique performed by a single surgeon on pediatric patients worldwide. Patients and methods: From June 2020 to February 2022, we performed TOETVA on 27 pediatric patients (≤ 18 years old). The outcomes of the procedure were retrospectively reviewed.ResultsOur study was conducted on 27 pediatric patients, of whom 24 were female (88.9%). The mean age was 16.3 ± 2 (range 10-18). Fifteen patients had benign thyroid nodules with a mean nodule size of 31.6 ± 7.1 (range 20-50mm), and 12 patients had papillary thyroid carcinoma with a mean nodule size of 10.2 ± 5.6 (range 4-19mm). All 27 patients underwent successful TOETVA without any conversion to open surgery. The 15 patients with benign thyroid nodules had lobectomies with a mean operative time of 83.3 ± 10.5 (range 60-105 minutes). Among the 12 patients diagnosed with thyroid cancer, ten had a lobectomy, isthmusectomy, and central neck dissection, with a mean operative time of 89.8 ± 5.7 (range 80-100 minutes). The other two underwent total thyroidectomy with central lymph node dissection with a mean operative time of 132.5 minutes. The mean hospital stay was 4.7 ± 0.9 (range 3-7 days). No patient had permanent complications, such as hypocalcemia, recurrent laryngeal nerve injury, or mental nerve injury. The rates of temporary recurrent laryngeal nerve injury and mental nerve injury were 3.7% and 11.1% respectively.ConclusionsTOETVA may be a feasible and safe surgical method for children with thyroid disease. However, we recommend that only high-volume thyroid surgeons with experience in TOETVA should perform TOETVA on the pediatric population

The impact of productivity on export transitions: revisited evidence from the Vietnamese manufacturing sectors

The effect of total factor productivity (TFP) on exports particularly interests policy-makers and economists, but empirical evidence is ambiguous. This paper uses the 6-wave panel data in 2010-2015 to investigate the impact of TFP on export transitions at the firm level. We distinguish different types of export transitions, namely start, stop, continuity, fluctuation, and striving, and different phases of export transition. The Generalised Method of Moments (GMM) estimation is applied to control for endogeneity and unobserved time-invariant specific components. The results reveal that (i) the effect of productivity on export (the self-selection hypothesis) is heterogeneous, depending on specific sectors and types and phases of export transitions; (ii) productivity growth does not necessarily result in positive effects on and lead to participation in types and phases of export transitions. Our results also reveal strong evidence of favourable sunk cost in long-run export striving in nearly all sectors, and unlike previous studies, empirical results show a negative effect of sunk cost in some manufacturing sectors. Policy-makers should create dynamic comparative advantages and favourable environments for new exporters, focus the relevant policies on productivity stimulus, and strengthen the likelihood of survival for the domestic firms in the competitive global markets

Optimizing Boiler Efficiency by Data Mining Teciques: A Case Study

In a fertilizer plant, the steam boiler is the most important component. In order to keep the plant operating in the effective mode, the boiler efficiency must be observed continuously by several operators. When the trend of the boiler efficiency is going down, they may adjust the controlling parameters of the boiler to increase its efficiency. Since manual operation usually leads to unex-pectedly mistakes and hurts the efficiency of the system, we build an information system that plays the role of the operators in observing the boiler and adjusting the controlling parameters to stabilize the boiler efficiency. In this paper, we first introduce the architecture of the information system. We then present how to apply K-means and Fuzzy C-means algorithms to derive a knowledge base from the historical operational data of the boiler. Next, recurrent fuzzy neural network is employed to build a boiler simulator for evaluating which tuple of input values is the best optimal and then automatically adjusting controlling inputs of the boiler by the optimal val-ues. In order to prove the effectiveness of our system, we deployed it at Phu My Fertilizer Plant equipped with MARCHI boiler having capacity of 76-84 ton/h. We found that our system have improved the boiler efficiency about 0.28-1.12% in average and brought benefit about 57.000 USD/year to the Phu My Fertilizer Plant

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

A modern purification by accelerated solvent extraction and centrifugal partition chromatography and biological evaluation of capsaicin from Capsicum chinense

A special alkaloid compound known as capsaicin, which can only be found in the fruit of the Capsicum plant, was isolated and tested for its anti-inflammatory activity. The purpose of this work is to establish a simple and quick approach for capsaicin purification utilizing centrifugal partition chromatography (CPC) as well as an effective method - accelerated solvent extraction (ASE), for extracting capsaicin from Capsicum chinense. After purification, capsaicin was validated by HPLC-DAD at 281 nm to be > 90% purity. The in vivo anti-inflammatory activity of the isolated capsaicin was also investigated, and the IC50 value of the capsaicin was determined to be 57.61 µg/mL. The current work emphasizes how an ASE and CPC system may combine to extract high-purity capsaicin from Capsicum chinense, which have the anti-inflammatory activity, as we evaluated in the experiment