Comprehensive assessment of real-time precise products from IGS analysis centers

Real-Time Precise Point Positioning(RT-PPP)has been one of the research hotspots in GNSS(Global Navigation Satellite System)community for decades.Real-time precise products of satellite orbits and clocks are the prerequisite for RT-PPP.Thus,it is of great importance to investigate the current multi-GNSS real-time precise products in State Space Representation(SSR)from diferent analysis centers.In this article,SSR products from 10 analysis centers are comprehensively evaluated by comparing them with the fnal products and performing the kinematic PPP.The results show that analysis centers CNES(Centre National D’Etudes Spatiales)and WHU(GNSS Research Center of Wuhan University)provide the most complete products with the best quality.Concerning the accuracy of real-time products for the GNSSs,the accuracies of orbit and clock products are better than 5 cm and 0.15 ns,respectively,for Global Positioning System(GPS),followed by Galileo navigation satellite system(Galileo),BeiDou-3 Navigation Satellite System(BDS-3),GLObal NAvigation Satellite System(GLONASS),and BeiDou-2 Navigation Satellite System(BDS-2).Meanwhile,the results of the RT-PPP with quad-system show that the positioning accuracies are 1.76,1.12 and 2.68 cm in east,north,and up directions,respectively,and the convergence time to 0.1,0.1,0.2 m for corresponding directions is 15.35 min.

Evolutionary-assisted reinforcement learning for reservoir real-time production optimization under uncertainty

Production optimization has gained increasing attention from the smart oilfield community because it can increase economic benefits and oil recovery substantially.While existing methods could produce high-optimality results,they cannot be applied to real-time optimization for large-scale reservoirs due to high computational demands.In addition,most methods generally assume that the reservoir model is deterministic and ignore the uncertainty of the subsurface environment,making the obtained scheme unreliable for practical deployment.In this work,an efficient and robust method,namely evolutionaryassisted reinforcement learning(EARL),is proposed to achieve real-time production optimization under uncertainty.Specifically,the production optimization problem is modeled as a Markov decision process in which a reinforcement learning agent interacts with the reservoir simulator to train a control policy that maximizes the specified goals.To deal with the problems of brittle convergence properties and lack of efficient exploration strategies of reinforcement learning approaches,a population-based evolutionary algorithm is introduced to assist the training of agents,which provides diverse exploration experiences and promotes stability and robustness due to its inherent redundancy.Compared with prior methods that only optimize a solution for a particular scenario,the proposed approach trains a policy that can adapt to uncertain environments and make real-time decisions to cope with unknown changes.The trained policy,represented by a deep convolutional neural network,can adaptively adjust the well controls based on different reservoir states.Simulation results on two reservoir models show that the proposed approach not only outperforms the RL and EA methods in terms of optimization efficiency but also has strong robustness and real-time decision capacity.

Performance analysis of real-time and post-mission kinematic precise point positioning in marine environments

This article focuses on the performance analysis of both real-time and post-mission kinematic precise point positioning(PPP)in challenging marine environments.For this purpose,a real dynamic experiment lasting 6 h was carried out on a lake dam in?orum City of Turkey.While the kinematic test was continuing,the real-time PPP coordinates were obtained for each measurement epoch with a commercial real-time PPP(RT-PPP)service,namely the Trimble Center Point RTX.Then the post-mission PPP(PM-PPP)coordinates were calculated by using Multi-GNSS data and the Multi-GNSS Experiment(MGEX)precise products.The kinematic RT-PPP and PM-PPP results showed that the PPP coordinates were consistent with the relative solution at centimetre and decimetre level in horizontal and height components,respectively.This study implies that PPP technique is a powerful tool for highly accurate positioning in both real-time and post-mission modes,even for dynamic applications in harsh environments.

Farmers’precision pesticide technology adoption and its influencing factors:Evidence from apple production areas in China

The research aimed to understand farmers’willingness to adopt(WTA)and willingness to pay(WTP)for precision pesticide technologies and analyzed the determinants of farmers’decision-making.We used a two-stage approach to consider farmers’WTA and WTP for precision pesticide technologies.A survey of 545 apple farmers was administered in Bohai Bay and the Loess Plateau in China.The data were analyzed using the double-hurdle model.The results indicated that 78.72%of respondents were willing to apply precision pesticide technologies provided by service organizations such as cooperatives and dedicated enterprises,and 69.72%were willing to buy the equipment for using precision pesticide technologies.The results of the determinant analysis indicated that farmers’perceived perceptions,farm scale,cooperative membership,access to digital information,and availability of financial services had significant and positive impacts on farmers’WTA precision pesticide technologies.Cooperative membership,technical training,and adherence to environmental regulations increased farmers’WTP for precision pesticide technologies.Moreover,nonlinear relationships between age,agricultural experience,and farmers’WTA and WTP for precision pesticide technology services were found.

Real-Time Iterative Compensation Framework for Precision Mechatronic Motion Control Systems

With regard to precision/ultra-precision motion systems,it is important to achieve excellent tracking performance for various trajectory tracking tasks even under uncertain external disturbances.In this paper,to overcome the limitation of robustness to trajectory variations and external disturbances in offline feedforward compensation strategies such as iterative learning control(ILC),a novel real-time iterative compensation(RIC)control framework is proposed for precision motion systems without changing the inner closed-loop controller.Specifically,the RIC method can be divided into two parts,i.e.,accurate model prediction and real-time iterative compensation.An accurate prediction model considering lumped disturbances is firstly established to predict tracking errors at future sampling times.In light of predicted errors,a feedforward compensation term is developed to modify the following reference trajectory by real-time iterative calculation.Both the prediction and compen-sation processes are finished in a real-time motion control sampling period.The stability and convergence of the entire control system after real-time iterative compensation is analyzed for different conditions.Various simulation results consistently demonstrate that the proposed RIC framework possesses satisfactory dynamic regulation capability,which contributes to high tracking accuracy comparable to ILC or even better and strong robustness.

The Real-Time,High Precision Phase Difference Measurement of Electron Density in HL-2A Tokamak

This paper introduces a real-time high precision measurement of phase difference based on Field Programmable Gate Array（FPGA） technology,which has been successfully applied to laser grating interference measurement and real-time feedback of plasma electron density in HL-2A tokamak.It can track the changes of electron density while setting the starting point of the density curve to zero.In a laboratory test,the measuring accuracy of phase difference is less than 0.1°,the time resolution is 80 ns,and the feedback delay is 180 μs.

Research and application of real-time monitoring and early warning thresholds for multi-temporal agricultural products information

Monitoring and early warning is an important means to effectively prevent risks in agricultural production,consumption and price.In particular,with the change of modes of national administration against the background of big data,improving the capacity to monitor agricultural products is of great significance for macroeconomic decision-making.Agricultural product information early warning thresholds are the core of agricultural product monitoring and early warning.How to appropriately determine the early warning thresholds of multi-temporal agricultural product information is a key question to realize real-time and dynamic monitoring and early warning.Based on the theory of abnormal fluctuation of agricultural product information and the research of substantive impact on the society,this paper comprehensively discussed the methods to determine the thresholds of agricultural product information fluctuation in different time dimensions.Based on the data of the National Bureau of Statistics of China(NBSC)and survey data,this paper used a variety of statistical methods to determine the early warning thresholds of the production,consumption and prices of agricultural products.Combined with Delphi expert judgment correction method,it finally determined the early warning thresholds of agricultural product information in multiple time,and carried out early warning analysis on the fluctuation of agricultural product monitoring information in 2018.The results show that:(1)the daily,weekly and monthly monitoring and early warning thresholds of agricultural products play an important early warning role in monitoring abnormal fluctuations with agricultural products;(2)the multitemporal monitoring and early warning thresholds of agricultural product information identified by the research institute can provide effective early warning on current abnormal fluctuation of agricultural product information,provide a benchmarking standard for China's agricultural production,consumption and price monitoring and early warning at the national macro level,and further improve the application of China's agricultural product monitoring and early warning.

Comparison of Two Real-time PCR Technigues for Quantification of GMO Contents in Highly Processed Products of Soybean

The RR soybean was quantitatively detected by ABI Prism 7300 sequence detector with PCR primers and fluorescence probes were designed according to the sequences of endogenous Lectin gene and exogenous CP4-EPSPS gene, and the PCR systems were based on SYBR Green I and TaqMan. The standard curve of ACt between CP4-EPSPS gene and Lectin gene of the RR soybean in standard materials was generated and a linear regression equation was obtained. Quantification methods were optimized through two different real-time PCR chemistries, i.e. SYBR Green I and TaqMan, and the RR soybean contents were quantified in five standard samples and seven highly processed products by the two assays. Both methods are proved to be specific, highly sensitive and reliable for both identification and quantification of soybean DNA. The results indicate that the two optimized PCR system can be used for the practical quantitative detection of RR soybean in highly processed products.

Rationally construction of atomic-precise interfacial charge transfer channel and strong build-in electric field in nanocluster-based Zscheme heterojunctions with enhanced photocatalytic hydrogen production

The lack of effective charge transfer driving force and channel limits the electron directional migration in nanoclusters(NC)-based heterostructures,resulting in poor photocatalytic performance.Herein,a Z-scheme NC-based heterojunction(Pt1Ag28-BTT/CoP,BTT=1,3,5-benzenetrithiol)with strong internal electric field is constructed via interfacial Co-S bond,which exhibits an absolutely superiority in photocatalytic performance with 24.89 mmol·h^(−1)·g−1 H_(2)production rate,25.77%apparent quantum yield at 420 nm,and~100%activity retention in stability,compared with Pt1Ag28-BDT/CoP(BDT=1,3-benzenedithiol),Ag29-BDT/CoP,and CoP.The enhanced catalytic performance is contributed by the dual modulation strategy of inner core and outer shell of NC,wherein,the center Pt single atom doping regulates the band structure of NC to match well with CoP,builds internal electric field,and then drives photogenerated electrons steering;the accurate surface S modification promotes the formation of Co-S atomic-precise interface channel for further high-efficient Z-scheme charge directional migration.This work opens a new avenue for designing NC-based heterojunction with matchable band structure and valid interfacial charge transfer.

Layering Precision Land Leveling and Furrow Irrigated Raised Bed Planting: Productivity and Input Use Efficiency of Irrigated Bread Wheat in Indo-Gangetic Plains

Stagnating yield and declining input use efficiency in irrigated wheat of the Indo-Gangetic Plain (IGP) coupled with diminishing availability of water for agriculture is a major concern of food security in South Asia. The objective of our study was to establish an understanding of how wheat yield and input use efficiency can be improved and how land leveling and crop establishment practices can be modified to be more efficient in water use through layering of precision-conservation crop management techniques. The “precision land leveling with raised bed” planting can be used to improve crop yield, water and nutrient use efficiency over the existing “traditional land leveling with flat” planting practices. We conducted a field experiment during 2002-2004 at Modipuram, India to quantify the benefits of alternate land leveling (precision land leveling) and crop establishment (furrow irrigated raised bed planting) techniques alone or in combination (layering precision-conservation) in terms of crop yield, water savings, and nutrient use efficiency of wheat production in IGP. The wheat yield was about 16.6% higher with nearly 50% less irrigation water with layering precision land leveling and raised bed planting compared to traditional practices (traditional land leveling with flat planting). The agronomic (AE) and uptake efficiency (UE) of N, P and K were significantly improved under precision land leveling with raised bed planting technique compared to other practices.

Techniques in Utilizing Remote Sensor Technology for Precision Crop Production by Farmers as Climate Change Adaptation Strategy in Nigeria

This paper focuses on techniques in utilizing remote sensor technology for precision crop production by farmers as climate change adaptation strategy in Nigeria. Descriptive survey research design was adopted for the study and was carried out between August 2013 and May 2014. The findings of the study revealed that 32 items were needed by farmers in utilizing sensory technology for precision crop production. The study recommended that the 32 items identified by the study should be utilized by extension agent in teaching the farmers the use of sensor technology for precision crop production while the farmers should make themselves available for the training.

Efficient Harmonic Analysis Technique for Prediction of IGS Real-Time Satellite Clock Corrections

Real-time satellite orbit and clock corrections obtained from the broadcast ephemerides can be improved using IGS real-time service (RTS) products. Recent research showed that applying such corrections for broadcast ephemerides can significantly improve the RMS of the estimated coordinates. However, unintentional streaming interruption may happen for many reasons such as software or hardware failure. Streaming interruption, if happened, will cause sudden degradation of the obtained solution if only the broadcast ephemerides are used. A better solution can be obtained in real-time if the predicted part of the ultra-rapid products is used. In this paper, Harmonic analysis technique is used to predict the IGS RTS corrections using historical broadcasted data. It is shown that using the predicted clock corrections improves the RMS of the estimated coordinates by about 72%, 58%, and 72% in latitude, longitude, and height directions, respectively and reduces the 2D and 3D errors by about 80% compared with the predicted part of the IGS ultra-rapid clock corrections.

Maximizing Oil Palm Yield: Innovative Replanting Strategies for Sustainable Productivity

This paper examines the significance of innovative replanting strategies in maximizing oil palm yield while ensuring sustainable productivity.Through a comprehensive review of literature and analysis of current practices,the major findings of this research highlighted the importance of advanced breeding and clonal selection in developing high-yielding and disease-resistant oil palm varieties.Precision agriculture technologies,including IoT devices,drones,and sensors,were identified as critical tools for data-driven decision making,optimizing resource efficiency,and reducing environmental impact.Sustainable land use planning and agroforestry integration emerged as key strategies to balance productivity with environmental conservation.The broader impacts of this work extend to other agricultural sectors and land use planning,offering valuable insights for policymakers and stakeholders to promote responsible and resilient agricultural practices.By embracing innovative replanting strategies,the oil palm industry can contribute to a more sustainable and prosperous future,balancing economic growth with environmental stewardship.Continued research and collaboration are essential to achieve these goals and foster a harmonious coexistence between productivity and sustainability,integrating precision agriculture technologies for resource optimization and reduced environmental impact,promoting sustainable land use planning and agroforestry integration to enhance biodiversity and ecosystem services.Strengthening collaborations between governments,industry players,and research institutions for innovation and knowledge exchange is essential.

无模型控制技术在丁二烯装置应用研究

对丁二烯控制技术的难点进行了剖析,重点阐述了无模型控制技术的基本原理、特性、功能、控制方法以及实现过程等,无模型控制技术通过对复杂控制系统进行闭环稳定安全控制,大大提高了生产设备的自动控制效率,改善了丁二烯产品品质,降低了生产技术人员的劳动强度,降低了因人为因素而产生的不安定影响,从而增加了生产设备运行的平稳性。无模型控制系国内丁二烯装置首次应用精准优化控制,可以实现脱重塔单元整体的闭环稳定控制,在无模型控制基础上实现黑屏操作的自控投用率为100%实现精准控制,增加丁二烯的产量,提高了产品质量;投用无模型控制后正常工况下控制回路波动范围上下限可减少30%左右,实现控制回路参数更加稳定,装置运行更加平稳,提高装置的安全性和装置的寿命,延长装置的运行周期。

科技创新推动茶叶质量安全全程管控能力提升

现阶段我国茶叶质量安全水平高,饮茶安全有保障。茶叶饮用安全得益于茶叶科技创新日益发展,茶园绿色防控技术、清洁化茶叶加工技术、茶叶质量安全精准检测技术与风险评估理论创新,将茶叶质量安全从末端监管调整到从茶园到茶杯的全过程,为茶叶质量安全风险监测、风险控制与风险管理提供强有力的科学支撑。性诱剂化学生态防控技术、杀虫灯与诱虫色板物理诱杀技术、茶尺蠖与茶毛虫病毒生物防治技术、以草抑草绿色除草技术等茶园绿色防控技术从源头提升了茶叶农药残留控制水平;清洁化能源加热替代传统的燃煤燃材加热方式,显著降低了茶叶加工中环境污染物和重金属等有害物质的污染;质谱创新技术将茶叶质量安全检测提升到高通量精准检测与非靶向筛查水平,速测创新技术前移了茶叶农药残留的监测环节。文章介绍了近年来我国茶叶质量安全水平,分析了科技创新对茶叶质量安全全程管控能力提升的推动作用。

新疆畜禽饲料资源中粗蛋白含量的调查研究

试验旨在研究新疆不同地州间各种常规饲料原料的粗蛋白含量和分布情况,为各地州饲粮合理配制提供科学依据。对新疆全区14个地州的13种115个主要畜禽饲料原料在科学采样的基础上进行粗蛋白含量测定。对同类不同种饲料样品和不同饲料样品的粗蛋白含量进行单因素方差分析,比较不同饲料原料中粗蛋白含量的差异及不同地区之间的差异。结果表明:不同原料除青贮玉米外,干物质含量都在92%以上;粮油加工副产物的粗蛋白含量最高,粮食作物秸秆粗蛋白含量最低。8个地州采集玉米样品中喀什的粗蛋白含量最高。全疆各地州的各种类饲料原料中粗蛋白含量相互之间变化非常大,因此,实际应用中要充分考虑到不同区域饲粮中粗蛋白含量,为精准配方、精准营养提供技术支撑。

国家预警工程综合地震波形分析系统设计与实现

随着国家地震烈度速报和预警工程的建设,中国测震站网的监测能力获得大幅提升,对于地震编目业务的要求也随之提升,传统的编目产品已无法满足新形势下的业务需求,用于支撑全国地震编目业务的系统亟需升级换代。本文介绍了国家预警工程软件系统之一的综合地震波形分析系统,通过对系统概况、功能实现、关键技术和业务应用等详细介绍,阐述该系统如何用于支撑国家预警工程建成后的全国新编目业务。大数据和人工智能技术飞速发展的时代将为该系统及其产出的编目产品提供更加广阔的发展和应用空间。

十万吨级深水半潜式生产储油平台船体建造过程控制分析

分析十万吨级深水半潜式生产储油平台船体建造过程中的相关技术要求,针对建造过程中的关键工序钢结构杆件下料尺寸控制、疲劳节点预制控制、脚手架辅助搭设、建造过程精度管理、船体管线总装过程中的难点等进行详细分析,总结出有效的控制建议,为后续类似浮体产品建造提供宝贵经验。

新质生产力视角下高精尖产业发展:分析框架与竞合趋势(2024)

加快形成新质生产力有助于促进科技水平实现质的飞跃,推进高精尖产业转型升级。高精尖产业发展需要以契合新质生产力水平的技术革新作为推进动能、需要符合新质生产力发展规律的市场环境支撑、需要遵循新质生产力发展要求的政策支持,同时应呈现出能够彰显新质生产力的先进特征的竞争力水平。本文以加快形成新质生产力为要旨,结合高精尖产业自身特点,构建十大高精尖产业趋势分析框架,分别对其技术趋势、市场趋势、政策趋势和竞争力趋势进行分析,同时结合发达经济体的经验,对我国高精尖产业发展的未来方向,从宏观、中观、微观三个层面提出了对策建议。

油管外接管生产线送料切断控制系统设计

针对油管外接管生产过程中切断精确度低、废料率高,各设备相互独立及自动化程度较低等问题,在传统钢管切割设备的基础上优化设计了精确送料单元、锁紧切割单元、自动下料单元。基于S7-1500 PLC进行了油管外接管自动生产线控制系统的硬件及软件设计,利用TIA Portal设计控制逻辑,采用西门子KTP1200人机交互面板对生产线工作状态进行实时监控,实现对整机的协调控制。实验测试表明,所设计的油管外接管自动生产线自动化程度高、运行稳定,显著提高了油管外接管的生产效率与自动化程度。