QoS Improvement Schemes for Real-Time Wireless VoIP

There is a tremendous demand on real-time multimedia delivery over wireless Internet due to the dramatic increase in wireless communication and the growth of the Internet. However, real-time multimedia over wireless Internet poses many challenges. First of all, the inherent best-effort characteristic of packet-switched networks makes it difficult to provide guaranteed QoS for real-time multimedia delivery. Secondly, wireless channels have much higher packet-loss rate, bit-error rate, and channel instability compared to wired channels due to noise, path loss, multi-path fading and shadowing, which result in fluctuating communication channel statistics. Thirdly, the real-time communication demands strict time limitations on the network end-to-end delay and delay jitter.In this dissertation, an intelligent application architecture and several QoS improvement mechanisms are proposed to timely estimate the current wireless network statistics and dynamically take smart actions to improve the overall performance of a real-time wireless Internet telephony system. An online network traffic modeling method based on time series analysis was used to estimate the dynamic wireless network statistics such as end-to-end packet delay and delay jitters. Using this real-time updated information, the application's sender side can take some adaptive actions such as voice codec selection and forward error-correction schemes for packet-loss concealment to improve the QoS under current available network resources. Also, a novel adaptive playout jitter buffer adjustment algorithm is proposed. The proposed algorithm achieved 11%-15% performance improvement compared to traditional adaptive playout adjustment algorithms using the ITU-E model measurement metric

Mineralogical and Geochemical Evidence for the Origin of the DL Uranium Deposit in the Songliao Basin, Northeast China

The DL deposit is a typical tabular-shaped U deposit hosted in sandstones of the Upper Cretaceous Yaojia Formation in the southwestern Songliao Basin, northeast China. Owing to its recent discovery, the origin of the deposit remains unclear. In this study, mineralogical and geochemical data were used to constrain the genesis of the DL deposit. Two sources of U were recognized: (1) pre-ore U enrichment in the Yaojia Formation during diagenesis; and (2) the provenance of the Yaojia Formation, which comprises late Permian–Early Cretaceous granitic rocks from the southern Great Xing’an Range and northern margin of the North China Craton, rather than the oils and diabase dikes in the study area. Mineralogical and geochemical characteristics indicate that organic matter (OM) in the Yaojia Formation was derived mainly from plant debris and hydrocarbons. In situ S isotope data for pyrite from the ore-bearing sandstones show that most of the pyrite has similar δ34S values (−43.8‰ to −20.6‰) to those of pyrite associated with bacterial sulfate reduction (BSR). The pyrite is often typically replaced and/or overgrown by pitchblende, which has a high P2O5 content (0.07–1.64 wt.%), indicative of a genetic relationship between BSR and U mineralization. The geological, mineralogical, and geochemical features suggest that the U mineralization in the DL deposit was mainly associated with BSR

Design and Experiment of Seed-Cleaning Mechanism for Inside-Filling Pneumatic Cotton Precision Seed-Metering Device

In order to solve the problem of the poor seed-cleaning performance of the inside-filling pneumatic cotton precision seed-metering device, a double-sided seed-cleaning mechanism combining a seed-cleaning scraper and seed-disturbing air nozzle was designed which can realize alternate seed cleaning on both sides of the suction hole’s end surface. By constructing a mechanical model of the seed-cleaning process, the influence law of the seed-cleaning mechanism on the critical adsorption performance of cotton seed was clarified, and the key structure and parameters of the seed-cleaning mechanism were decided by combining a theoretical analysis with operational requirements. So as to explore the seed-cleaning performance, some relevant bench tests were carried out, with E’kangmian-10 coated de-linted cotton seeds with a moisture content of 8.92% (wet basis) serving as the test objects; and single seed rate, excessive cleaning rate, and missing cleaning rate were taken for test indicators. First of all, a single-factor comparison test was employed with the shape of the seed-cleaning scraper as the impact factor to choose the optimal one. The results of the comparison test showed that, no matter what shape of seed-cleaning scraper was adopted for the seed-metering device, the missing cleaning rates under the corresponding optimal seed-cleaning effect were greater than 5%, and the sharp scraper gave a better seed-cleaning performance than the flat scraper. Next, combining the sharp seed-cleaning scraper with the seed-disturbing air nozzle to form combined seed-cleaning mechanism of the seed-metering device, the Box–Behnken Design test was executed to explore the influence law about seed-cleaning distance, seed-disturbing distance, and seed-disturbing pressure on the seed-cleaning performance. Then the parameter optimization module was applied to achieve the best combination of operating parameters for the test factors. The test results indicated that the test factors influencing test indicators were in the following order: seed-cleaning distance, seed-disturbing pressure, and seed-disturbing distance. The optimal combination of parameters was a seed-cleaning distance of 3.1 mm, seed-disturbing distance of 6.2 mm, and seed-disturbing pressure of 2165 Pa. Lastly, based on the optimal combination, a verification test of seed-cleaning performance was performed, and the corresponding evaluation indexes were a single seed rate of 98.03%, missing cleaning rate of 1.42%, and excessive cleaning rate of 0.55%. In comparison with the optimal seed-cleaning effects under the single-sided seed-cleaning scrapers of flat and sharp shape, respectively, the combined double-sided seed-cleaning mechanism reduced 3.90 and 3.61 percentage points in missing cleaning rate, reduced 2.02 and 1.17 percentage points in excessive cleaning rate, and increased 5.92 and 4.78 percentage points in single seed rate, thus indicating that the combined double-sided seed-cleaning mechanism can effectively enhance the inside-filling pneumatic precision seed-metering device seed-cleaning performance. This study provides a reference for the design and parameter optimization of the seed-cleaning mechanism of a precision seed-metering device

Development of a Depth Control System Based on Variable-Gain Single-Neuron PID for Rotary Burying of Stubbles

Rotary burying by tractor-hitched rotary tillers is a common practice in southern China for treating rice stubbles. Currently, it is difficult to maintain stable tillage depths due to surface unevenness and the residual stubbles in the field, which leads to unstable tillage quality and nonuniform crop growth in later stages. In this study, an RTK-GNSS was used to measure the real-time height and roll angle of the tractor, and a variable-gain single-neuron PID control algorithm was designed to adjust the coefficients (KP, KI, and KD) and gain K in real-time according to the control effects. An on-board computer sent the angles of the upper swing arm u(t) to an STM32 microcontroller through a CAN bus. Compared with the current angle of the upper swing arm, the microcontroller controlled an electronic-control proportional hydraulic system, so that the height of the rotary tiller could be adjusted to follow the field undulations in real-time. Field experiments showed that when the operation speed of the tractor-rotary tiller system was about 0.61 m/s, the variable-gain single-neuron PID algorithm could effectively improve the stability of the working depth and the stubbles’ burying rate. Compared with a conventional PID controller, the stability coefficient and the stubbles’ burying rate were improved by 5.85% and 4.38%, respectively, and compared with a single-neuron PID controller, the stability coefficient and the stubbles’ burying rate were improved by 4.37% and 3.49%, respectively. This work controlled the working depth of the rotary tiller following the changes in the field surface in real-time and improved the stubbles’ burying rate, which is suitable for the unmanned operation of the rotary burying of stubbles in the future

Bioactivities and formation/utilization of soluble microbial products (SMP) in the biological sulfate reduction under different conditions

The biological sulfate reduction (BSR) plays a critical role in the organic compound removal in the sulfur bioconversion-associated sewage treatment process. The soluble microbial products (SMP) are the major components of residual organic compounds in the secondary treatment effluent and its presence directly affects treatment capacity. In addition, the SMP could be one of the available organic substrates and be utilized as an electron donor in the bioreactions. However, the SMP formation and utilization in the BSR are poorly understood. Herein, the BSR activities and SMP generation/utilization were simultaneously investigated under different conditions, i.e. pH, temperature and ratio of organic carbon (C) to sulfur (S). The role of SMP as the electron donor for BSR was also identified. The higher BSR activities and rapid SMP synthesis were found under neutral and alkaline conditions, but the SMP utilization as the electron donor is not favorable at pH 7.0. The BSR activity became higher and more SMP was synthesized by raising the temperature. The ratio of C to S rarely affected the sulfidogenic activity but has an effect on the net SMP generation (total SMP generation - SMP consumption by SBR as the electron donor). The lower ratio of C/S could result in the low residual SMP level in the reactor. And the SMP-induced BSR activity was higher under the acid and alkaline conditions compared with the neutral condition.This work was financially supported by the National Natural Science Foundation of China (No. 51608444) and the Natural Science Foundation of Shenzhen (No. JCYJ20170306153655840). Dr. Jin Qian wishes to thank the Fundamental Research Funds for Central Universities (No. 3102017zy002)

A novel integrated thiosulfate-driven denitritation (TDD) and anaerobic ammonia oxidation (anammox) process for biological nitrogen removal

An integrated system by combining the thiosulfate-driven denitritation (TDD) and anaerobic ammonia oxidation (anammox) was established for high-rate biological nitrogen removal (BNR) and less N2O generation under 35 °C. The anammox contribute to 27% nitrogen removal in the system. The anammox activity was enhanced by four times as temperature increased from 20 to 35 °C. The less N2O emission at 35 °C compared with that at 20 °C is attributed to the involvement of anammox (characterized as no N2O generation) function rather than higher N2O reducing rate under the thermophilic condition. The produced NO3− in anammox can be readily reduced by thiosulfate. The results of this study could enlighten us how to induce a high nitrogen degradation activity with lower sludge yield, in the meanwhile to minimize the greenhouse gas emission and the nitrogenous residues in the BNR process

Measurement and Calibration of the Discrete Element Parameters of Coated Delinted Cotton Seeds

To simulate the interactions between a pneumatic cotton precision seed-metering device and coated delinted cotton seeds accurately, physical and simulation experiments based on a rotating drum apparatus were combined to calibrate the discrete element simulation parameters of E`kangmian-10 cotton seeds. Firstly, the contact parameters and the dynamic repose angle of the cotton seeds were measured through physical tests. Based on the particle size requirement of the Discrete Element Method (DEM) and Computational Fluid Dynamics (CFD) coupling simulation and the reverse engineering technology, the cotton seed discrete element bonded-particle model (BPM) was established. Secondly, taking the contact parameters as calibration objects and the simulated dynamic repose angle as the evaluation index, a Plackett–Burman (PB) test was designed for significance screening. The results of the screening test showed that the static friction coefficient of cotton seed–tough photosensitive resin, the impact recovery coefficient of cotton seed–cotton seed, and the static friction coefficient of cotton seed–cotton seed had a highly significant effect on the simulated dynamic repose angle. Next, a Box–Behnken Design (BBD) test was adopted to establish the quadratic regression model between significant parameters and the simulated dynamic repose angle, and then the multi-factor optimization solution was carried out to obtain the optimal combination of parameters: the static friction coefficient of cotton seed–tough photosensitive resin and the impact recovery coefficient and static friction coefficient of cotton seed–cotton seed were 0.33, 0.06 and 0.10, respectively. Lastly, verification tests on the rotating drum apparatus and the seed-metering device were performed, and their relative errors were less than 2%, which indicated that the discrete element models and the contact parameters of the coated delinted cotton seeds were reliable. This study provides a reference for the selection of the discrete element parameters of coated delinted cotton seeds for DEM-CFD coupling simulation and the optimal design of precision seed-metering device for cotton

Effects and mechanisms on the reduction of lead accumulation in rice grains through lime amendment

The influence of lime amendment on the absorption and accumulation of lead (Pb) in the grains of three rice cultivars ((Dong Lian 5 (DL-5, Indica), TeYou 009 (TY-009, Hybrid Indica), and YiYou 673 (YY-673, Hybrid Indica)) was investigated and the associated mechanisms were explored. Pot experiment was conducted in heavily Pb-polluted paddy soil. The transformation of Pb species in soil and roots under different levels of lime application was studied by Pb L3-edge X-ray absorption spectroscopy (Pb L3-XAS) and BCR sequential extraction. The results showed that lime amendment significantly increased soil pH and decreased DTPA-extractable Pb in soil. When the additional ratio of Liming was lower than 32 g kg–1, the Pb accumulation in rice plants, particularly in the grains was remarkably reduced. Moreover the biomass of rice was not significantly affected. Among the three cultivars, the lowest Pb content in rice grains occurred in YY-673. The cultivation of rice cultivar with low Pb accumulation will reduce the Pb content in the grains. Liming significantly inhibited the translocation of Pb from the roots to the aboveground parts, and from the stems and leaves to grains. Pb L3-XAS and BCR s sequential extraction method analysis revealed that lime amendment increased Pb2+ association with Fe oxides (Pb-Ferr), the precipitation of 2PbCO3·Pb(OH)2, the residual fraction of paddy soil, and also promoted the transformation of Pb(NO3)2 and Pb-pectin to 2PbCO3·Pb(OH)2 and Pb-Ferr in rice roots. The suitable lime addition (> 4 g kg–1, under this pot experiment) could effectively reduce Pb accumulation in rice grains

QuanTaichi: a compiler for quantized simulations

High-resolution simulations can deliver great visual quality, but they are often limited by available memory, especially on GPUs. We present a compiler for physical simulation that can achieve both high performance and significantly reduced memory costs, by enabling flexible and aggressive quantization. Low-precision ("quantized") numerical data types are used and packed to represent simulation states, leading to reduced memory space and bandwidth consumption. Quantized simulation allows higher resolution simulation with less memory, which is especially attractive on GPUs. Implementing a quantized simulator that has high performance and packs the data tightly for aggressive storage reduction would be extremely labor-intensive and error-prone using a traditional programming language. To make the creation of quantized simulation practical, we have developed a new set of language abstractions and a compilation system. A suite of tailored domain-specific optimizations ensure quantized simulators often run as fast as the full-precision simulators, despite the overhead of encoding-decoding the packed quantized data types. Our programming language and compiler, based on Taichi , allow developers to effortlessly switch between different full-precision and quantized simulators, to explore the full design space of quantization schemes, and ultimately to achieve a good balance between space and precision. The creation of quantized simulation with our system has large benefits in terms of memory consumption and performance, on a variety of hardware, from mobile devices to workstations with high-end GPUs. We can simulate with levels of resolution that were previously only achievable on systems with much more memory, such as multiple GPUs. For example, on a single GPU, we can simulate a Game of Life with 20 billion cells (8× compression per pixel), an Eulerian fluid system with 421 million active voxels (1.6× compression per voxel), and a hybrid Eulerian-Lagrangian elastic object simulation with 235 million particles (1.7× compression per particle). At the same time, quantized simulations create physically plausible results. Our quantization techniques are complementary to existing acceleration approaches of physical simulation: they can be used in combination with these existing approaches, such as sparse data structures, for even higher scalability and performance. </jats:p

Table_1_Exploring the potential of the sit-to-stand test for self-assessment of physical condition in advanced knee osteoarthritis patients using computer vision.DOCX

IntroductionKnee osteoarthritis (KOA) is a prevalent condition often associated with a decline in patients’ physical function. Objective self-assessment of physical conditions poses challenges for many advanced KOA patients. To address this, we explored the potential of a computer vision method to facilitate home-based physical function self-assessments.MethodsWe developed and validated a simple at-home artificial intelligence approach to recognize joint stiffness levels and physical function in individuals with advanced KOA. One hundred and four knee osteoarthritis (KOA) patients were enrolled, and we employed the WOMAC score to evaluate their physical function and joint stiffness. Subsequently, patients independently recorded videos of five sit-to-stand tests in a home setting. Leveraging the AlphaPose and VideoPose algorithms, we extracted time-series data from these videos, capturing three-dimensional spatiotemporal information reflecting changes in key joint angles over time. To deepen our study, we conducted a quantitative analysis using the discrete wavelet transform (DWT), resulting in two wavelet coefficients: the approximation coefficients (cA) and the detail coefficients (cD).ResultsOur analysis specifically focused on four crucial joint angles: “the right hip,” “right knee,” “left hip,” and “left knee.” Qualitative analysis revealed distinctions in the time-series data related to functional limitations and stiffness among patients with varying levels of KOA. In quantitative analysis, we observed variations in the cA among advanced KOA patients with different levels of physical function and joint stiffness. Furthermore, there were no significant differences in the cD between advanced KOA patients, demonstrating different levels of physical function and joint stiffness. It suggests that the primary difference in overall movement patterns lies in the varying degrees of joint stiffness and physical function among advanced KOA patients.DiscussionOur method, designed to be low-cost and user-friendly, effectively captures spatiotemporal information distinctions among advanced KOA patients with varying stiffness levels and functional limitations utilizing smartphones. This study provides compelling evidence for the potential of our approach in enabling self-assessment of physical condition in individuals with advanced knee osteoarthritis.</p