Some Local-Global Principles for Formally Real Fields

1977 ◽  
Vol 29 (3) ◽  
pp. 606-614 ◽  
Author(s):  
M. Marshall
Keyword(s):  
Real Field ◽  
Global Principles

Let F be a formally real field, and let A be a preordering of F; that is, a subset of F satisfying Δ + Δ = Δ, Δ Δ = Δ, F2 ⊆ Δ. Denote by X Δ the set of all orderings P of F satisfying P ⊇ Δ. Thus Δ = ⋂ p ∈xΔP. This result is well known. It was first proved by Artin [3, Satz 1] in the case Δ = ∑ F2.

Stochastic simulation of the spatio-temporal field of the average daily heat index in Southern Russia

2020 ◽  
Vol 82 ◽  
pp. 149-160
Author(s):  
N Kargapolova
Keyword(s):  
Heat Waves ◽  
Numerical Models ◽  
Heat Index ◽  
Real Field ◽  
Gaussian Field ◽  
The Real ◽  
Southern Russia ◽  
Weather Stations ◽  
Spatio Temporal ◽  
Temporal Field

Numerical models of the heat index time series and spatio-temporal fields can be used for a variety of purposes, from the study of the dynamics of heat waves to projections of the influence of future climate on humans. To conduct these studies one must have efficient numerical models that successfully reproduce key features of the real weather processes. In this study, 2 numerical stochastic models of the spatio-temporal non-Gaussian field of the average daily heat index (ADHI) are considered. The field is simulated on an irregular grid determined by the location of weather stations. The first model is based on the method of the inverse distribution function. The second model is constructed using the normalization method. Real data collected at weather stations located in southern Russia are used to both determine the input parameters and to verify the proposed models. It is shown that the first model reproduces the properties of the real field of the ADHI more precisely compared to the second one, but the numerical implementation of the first model is significantly more time consuming. In the future, it is intended to transform the models presented to a numerical model of the conditional spatio-temporal field of the ADHI defined on a dense spatio-temporal grid and to use the model constructed for the stochastic forecasting of the heat index.

THE ANALYSIS OF PROBLEM BASED LEARNING (PBL) IN MICRO TEACHING COURSE TO FIT THE REQUIREMENT OF EFFECTIVE PRE-SERVICE TEACHERS

2019 ◽  
Vol 7 (2) ◽  
pp. 119
Author(s):  
Linda Linda ◽  
Apandi
Keyword(s):  
Qualitative Method ◽  
Teaching Practice ◽  
Problem Based Learning ◽  
Real Field ◽  
English Department ◽  
Effective Teacher ◽  
Existing Problems ◽  
Apply Problem ◽  
Pre Service Teacher

One of phenomena that occur in the educational world is the issue of discrepancies that occur between theory the pre-service teacher learned in college with implementation when they should teach in thereal fields (schools). Problem Based Learning (PBL) becomes one of the efforts to bridge the existing problems. This research is conducted to find out the extend of Problem Based Learning (PBL) in Micro Teaching course since the course must be accomplished by students before carrying out practical activities in the real field in the school at teaching training program. The writer uses descriptive qualitative method. And in this research the writer uses case study as a research design to find out the purpose of the research. The participants of the the research are 8 students from a class of micro teaching course in English Department of Universitas Swadaya Gunung Jati. In this paper, The Students as the Pre Service Teacher(s) are coded PST(s). The writer uses observation as the instruments of the research. Theory of Miles and Huberman are used to collect data from observation. Regarding to the discussion above, the four aspects of competences of effective teacher are shown in the teaching practice done by the students of Micro teaching course that apply Problem Based Learning (PBL). The majority results of the observation explain that applying Problem Based Learning in Micro Teaching course develops pre-service teachers competence in their teaching in classroom. This research shows pre-service teachers can integrate their competences and create good performance in their teaching practice.

scholarly journals Use of Concentric Hele-Shaw Cell for the Study of Displacement Flow and Interface Tracking in Primary Cementing

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 51
Author(s):  
Amir Taheri ◽  
Jan David Ytrehus ◽  
Bjørnar Lund ◽  
Malin Torsæter
Keyword(s):  
Yield Stress ◽  
Drilling Fluid ◽  
Co2 Storage ◽  
Main Idea ◽  
Real Field ◽  
Interface Tracking ◽  
Pressure Gradients ◽  
Cell Geometry ◽  
Primary Cementing ◽  
Hele Shaw Cell

We present our new designed concentric Hele-Shaw cell geometry with dynamic similarity to a real field wellbore annulus during primary cementing, and then, the results of displacement flow of Newtonian and yield-stress non-Newtonian fluids in it are described. The displacement stability and efficiency, the effect of back, front, and side boundaries on displacement, bypassing pockets of displaced yield-stress fluid in displacing fluid, and the behavior of pressure gradients in the cell are investigated. Applications of intermediate buoyant particles with different sizes and densities intermediate between those of successively pumped fluids for tracking the interface between the two displaced and displacing fluids are examined. The main idea is to upgrade this concentric Hele-Shaw cell geometry later to an eccentric one and check the possibility of tracking the interface between successive fluids pumped in the cell. Successful results help us track the interface between drilling fluid and spacer/cement during primary cementing in wells penetrating a CO2 storage reservoir and decreasing the risk of CO2 leakage from them.

scholarly journals Wireless Sensor Networks for Smart Cities: Network Design, Implementation and Performance Evaluation

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 218
Author(s):  
Ala’ Khalifeh ◽  
Khalid A. Darabkh ◽  
Ahmad M. Khasawneh ◽  
Issa Alqaisieh ◽  
Mohammad Salameh ◽  
...  
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Experimental Evaluation ◽  
Large Scale ◽  
Performance Metrics ◽  
Smart Cities ◽  
Field Tests ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Real Field

The advent of various wireless technologies has paved the way for the realization of new infrastructures and applications for smart cities. Wireless Sensor Networks (WSNs) are one of the most important among these technologies. WSNs are widely used in various applications in our daily lives. Due to their cost effectiveness and rapid deployment, WSNs can be used for securing smart cities by providing remote monitoring and sensing for many critical scenarios including hostile environments, battlefields, or areas subject to natural disasters such as earthquakes, volcano eruptions, and floods or to large-scale accidents such as nuclear plants explosions or chemical plumes. The purpose of this paper is to propose a new framework where WSNs are adopted for remote sensing and monitoring in smart city applications. We propose using Unmanned Aerial Vehicles to act as a data mule to offload the sensor nodes and transfer the monitoring data securely to the remote control center for further analysis and decision making. Furthermore, the paper provides insight about implementation challenges in the realization of the proposed framework. In addition, the paper provides an experimental evaluation of the proposed design in outdoor environments, in the presence of different types of obstacles, common to typical outdoor fields. The experimental evaluation revealed several inconsistencies between the performance metrics advertised in the hardware-specific data-sheets. In particular, we found mismatches between the advertised coverage distance and signal strength with our experimental measurements. Therefore, it is crucial that network designers and developers conduct field tests and device performance assessment before designing and implementing the WSN for application in a real field setting.

Cultivating AI Talents through Real Field Competition

2020 ◽  
Author(s):  
Gia-Wei Kuo ◽  
Hsiao-Chien Tseng ◽  
Shih-Hsin Hu ◽  
Hui-Yun Lin ◽  
Pei-Yu Lu ◽  
...  
Keyword(s):  
Real Field

scholarly journals Recent advances toward the sustainable management of invasive Xylosandrus ambrosia beetles

2021 ◽  
Author(s):  
Antonio Gugliuzzo ◽  
Peter H. W. Biedermann ◽  
Daniel Carrillo ◽  
Louela A. Castrillo ◽  
James P. Egonyu ◽  
...  
Keyword(s):  
Urban Areas ◽  
Physiological Stress ◽  
Plant Stress ◽  
Real Field ◽  
Broad Host Range ◽  
Ambrosia Beetles ◽  
Baited Traps ◽  
Rapid Spread ◽  
Mycoparasitic Fungi ◽  
History Of

AbstractWe provide an overview of both traditional and innovative control tools for management of three Xylosandrus ambrosia beetles (Coleoptera: Curculionidae: Scolytinae), invasive species with a history of damage in forests, nurseries, orchards and urban areas. Xylosandrus compactus, X. crassiusculus and X. germanus are native to Asia, and currently established in several countries around the globe. Adult females bore galleries into the plant xylem inoculating mutualistic ambrosia fungi that serve as food source for the developing progeny. Tunneling activity results in chewed wood extrusion from entry holes, sap outflow, foliage wilting followed by canopy dieback, and branch and trunk necrosis. Maintaining plant health by reducing physiological stress is the first recommendation for long-term control. Baited traps, ethanol-treated bolts, trap logs and trap trees of selected species can be used to monitor Xylosandrus species. Conventional pest control methods are mostly ineffective against Xylosandrus beetles because of the pests’ broad host range and rapid spread. Due to challenges with conventional control, more innovative control approaches are being tested, such as the optimization of the push–pull strategy based on specific attractant and repellent combinations, or the use of insecticide-treated netting. Biological control based on the release of entomopathogenic and mycoparasitic fungi, as well as the use of antagonistic bacteria, has yielded promising results. However, these technologies still require validation in real field conditions. Overall, we suggest that management efforts should primarily focus on reducing plant stress and potentially be combined with a multi-faceted approach for controlling Xylosandrus damage.

scholarly journals New Hybrid Approach for Developing Automated Machine Learning Workflows: A Real Case Application in Evaluation of Marcellus Shale Gas Production

Fuels ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 286-303
Author(s):  
Vuong Van Pham ◽  
Ebrahim Fathi ◽  
Fatemeh Belyadi
Keyword(s):  
Artificial Intelligence ◽  
Machine Learning ◽  
Shale Gas ◽  
Field Data ◽  
Marcellus Shale ◽  
Hybrid Approach ◽  
Gas Production ◽  
Bayesian Optimization ◽  
Real Field ◽  
Engineering Problems

The success of machine learning (ML) techniques implemented in different industries heavily rely on operator expertise and domain knowledge, which is used in manually choosing an algorithm and setting up the specific algorithm parameters for a problem. Due to the manual nature of model selection and parameter tuning, it is impossible to quantify or evaluate the quality of this manual process, which in turn limits the ability to perform comparison studies between different algorithms. In this study, we propose a new hybrid approach for developing machine learning workflows to help automated algorithm selection and hyperparameter optimization. The proposed approach provides a robust, reproducible, and unbiased workflow that can be quantified and validated using different scoring metrics. We have used the most common workflows implemented in the application of artificial intelligence (AI) and ML in engineering problems including grid/random search, Bayesian search and optimization, genetic programming, and compared that with our new hybrid approach that includes the integration of Tree-based Pipeline Optimization Tool (TPOT) and Bayesian optimization. The performance of each workflow is quantified using different scoring metrics such as Pearson correlation (i.e., R2 correlation) and Mean Square Error (i.e., MSE). For this purpose, actual field data obtained from 1567 gas wells in Marcellus Shale, with 121 features from reservoir, drilling, completion, stimulation, and operation is tested using different proposed workflows. A proposed new hybrid workflow is then used to evaluate the type well used for evaluation of Marcellus shale gas production. In conclusion, our automated hybrid approach showed significant improvement in comparison to other proposed workflows using both scoring matrices. The new hybrid approach provides a practical tool that supports the automated model and hyperparameter selection, which is tested using real field data that can be implemented in solving different engineering problems using artificial intelligence and machine learning. The new hybrid model is tested in a real field and compared with conventional type wells developed by field engineers. It is found that the type well of the field is very close to P50 predictions of the field, which shows great success in the completion design of the field performed by field engineers. It also shows that the field average production could have been improved by 8% if shorter cluster spacing and higher proppant loading per cluster were used during the frac jobs.

scholarly journals Field assessment of a pulse width modulation (PWM) spray system applying different spray volumes: duty cycle and forward speed effects on vines spray coverage

2021 ◽  
Author(s):  
Marco Grella ◽  
Fabrizio Gioelli ◽  
Paolo Marucco ◽  
Ingrid Zwertvaegher ◽  
Eric Mozzanini ◽  
...  
Keyword(s):  
Precision Agriculture ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Plant Protection ◽  
Plant Protection Products ◽  
Field Conditions ◽  
Advanced Technology ◽  
Real Field ◽  
Spray Application ◽  
Spray System

AbstractThe pulse width modulation (PWM) spray system is the most advanced technology to obtain variable rate spray application without varying the operative sprayer parameters (e.g. spray pressure, nozzle size). According to the precision agriculture principles, PWM is the prime technology that allows to spray the required amount where needed without varying the droplet size spectra which benefits both the uniformity of spray quality and the spray drift reduction. However, some concerns related to the effect of on–off solenoid valves and the alternating on/off action of adjacent nozzles on final uneven spray coverage (SC) have arisen. Further evaluations of PWM systems used for spraying 3D crops under field conditions are welcomed. A tower-shaped airblast sprayer equipped with a PWM was tested in a vineyard. Twelve configurations, combining duty cycles (DC: 30, 50, 70, 100%) and forward speeds (FS: 4, 6, 8 km h−1), were tested. Two methodologies, namely field-standardized and real field conditions, were adopted to evaluate the effect of DC and FS on (1) SC variability (CV%) along both the sprayer travel direction and the vertical spray profile using long water sensitive papers (WSP), and (2) SC uniformity (IU, index value) within the canopy at different depths and heights, respectively. Furthermore, the SC (%) and deposit density (Nst, no stains cm−2), determined using short WSP, were used to evaluate the spray application performances taking into account the spray volumes applied. Under field-controlled conditions, the pulsing of the PWM system affects both the SC variability measured along the sprayer travel direction and along the vertical spray profile. In contrast, under real field conditions, the PWM system does not affect the uniformity of SC measured within the canopy. The relationship between SC and Nst allowed identification of the ranges of 200–250 and 300–370 l ha−1 as the most suitable spray volumes to be applied for insecticide and fungicide plant protection products, respectively.

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