scholarly journals Comparison of weed control techniques to establish three ground cover species

2010 ◽  
Vol 63 ◽  
pp. 96-101 ◽  
Author(s):  
C.L. Foo ◽  
K.C. Harrington ◽  
M.B. MacKay
Keyword(s):  
Weed Control ◽  
Control Strategy ◽  
Control Strategies ◽  
Ground Cover ◽  
Late Spring ◽  
Control Techniques

Weed control strategies for establishing three ground cover species were investigated by planting them in late spring then assessing eight different control treatments during the following 14 months The prostrate woody Coprosma acerosa Taiko established best with black weed mat mulch and EcoCover paper mulch although bark mulches also gave reasonable establishment rates The brittle succulent Sedum mexicanum Acapulco Gold also established well with black weed mat and paper mulch although a sawdust mulch was particularly suitable The frostprone Polygonum capitatum which regrows readily from seed did best with soil kept bare by handhoeing or selective herbicides although the paper mulch also rated well Thus the best weed control strategy varied depending on the characteristics of the ground cover being established Other considerations including relative costs are also discussed

Consumer Preferences for Sustainable Wine Attributes: A Conjoint Analysis

2017 ◽  
Vol 12 (4) ◽  
pp. 416-425 ◽  
Author(s):  
Kathleen M. Kelley ◽  
Jennifer Zelinskie ◽  
Michela Centinari ◽  
Denise M. Gardner ◽  
Ramu Govindasamy ◽  
...  
Keyword(s):  
Weed Control ◽  
Conjoint Analysis ◽  
Control Strategy ◽  
Cover Crops ◽  
Consumer Preferences ◽  
Control Strategies ◽  
Control Measure ◽  
Internet Survey ◽  
Base Price ◽  
Bunch Rot

AbstractMid-Atlantic wine consumers participated in an Internet survey to determine which of three attributes (retail base prices, Botrytis cinerea [bunch rot] control measure, or weed-control strategy) and attribute levels (e.g., a retail base price of $12, $16, $22, or $26) were the most important factors in their decisions to purchase 750mL glass bottles of wine. Conjoint analysis was used to calculate average importance for the three attributes. Based on these calculations, the base retail price attribute had the greatest impact on participants’ decision to purchase the wine (57.40%), followed by bunch rot control measure (20.76%) and weed control strategy (21.49%). Participants were also asked to indicate how interested (not at all interested to extremely interested) they were in purchasing wines produced from grapes grown using minimal pesticides or with cover crops to control weeds. Separate conjoint analyses were then performed based on participants’ level of interest in the two sustainable production methods. In both instances, the average importance values for retail base price were still higher than the values for either bunch rot or weed control strategies. Average importance values for price were lower for participants who responded that they were “very” or “extremely interested” in purchasing wine produced with minimal pesticides or with cover crops than for participants who were “not all interested” in purchasing such wines. (JEL Classifications: Q18, Q11, M31)

scholarly journals Optimal Control Techniques on a Mathematical Model for the Dynamics of Tungiasis in a Community

2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
Jairos Kahuru ◽  
Livingstone S. Luboobi ◽  
Yaw Nkansah-Gyekye
Keyword(s):  
Mathematical Model ◽  
Optimal Control ◽  
Control Strategy ◽  
Control Strategies ◽  
Control Process ◽  
Control Measures ◽  
Human Beings ◽  
Optimal Control Strategy ◽  
Control Techniques ◽  
Existence Of Optimal Control

Tungiasis is a permanent penetration of female sand flea“Tunga penetrans”into the epidermis of its host. It affects human beings and domestic and sylvatic animals. In this paper, we apply optimal control techniques to a Tungiasis controlled mathematical model to determine the optimal control strategy in order to minimize the number of infested humans, infested animals, and sand flea populations. In an attempt to reduce Tungiasis infestation in human population, the control strategies based on personal protection, personal treatment, educational campaign, environmental sanitation, and insecticidal treatments on the affected parts as well as on animal fur are considered. We prove the existence of optimal control problem, determine the necessary conditions for optimality, and then perform numerical simulations. The numerical results showed that the control strategy comprises all five control measures and that which involves the three control measures of insecticide control, insecticidal dusting on animal furs, and environmental hygiene has the significant impact on Tungiasis transmission. Therefore, fighting against Tungiasis infestation in endemic settings, multidimensional control process should be employed in order to achieve the maximum benefits.

A Review of Classical and Modern Control Techniques Utilized in Modern Microgrids

2021 ◽  
Vol 14 ◽  
Author(s):  
Muhammad Hamza Shahbaz ◽  
Arslan Ahmed Amin
Keyword(s):  
Control Strategies ◽  
Optimal Solution ◽  
Energy Resources ◽  
Control Methods ◽  
Research Gaps ◽  
Control Techniques ◽  
Micro Grid ◽  
Exciting Development ◽  
Micro Grids ◽  
Modern Control

: Because of the consistently expanding energy request, the introduction of a decentralized micro-grid based on energy resources will soon be the most exciting development in the power system. Micro-grids, which are mainly based on inverters, are becoming more popular as they can handle different forms of renewable energy effectively. However, one of the most challenging areas of research is their control. In the last few years, many control strategies have been developed. In this review, different control methods have been discussed that apply to the micro-grid system. Furthermore, the comparative analysis of classical and modern control strategies is also considered. This survey guides the new researchers about all available control strategies and room for improvement towards the optimal solution of the micro-grid control techniques. It also identifies several research gaps and future trends therein as well as provides a solution to manage problems in MGs. The strategies are then compared based on their applicability to different control requirements.

scholarly journals Comparison of Advanced Charge Strategies for Modular Cascaded Battery Chargers

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3361
Author(s):  
Nicolas T. D. Fernandes ◽  
Anderson Rocha ◽  
Danilo Brandao ◽  
Braz C. Filho
Keyword(s):  
Control Strategies ◽  
Measure Data ◽  
Capacity Fade ◽  
Battery Lifetime ◽  
Control Techniques ◽  
Battery Model ◽  
Battery Chargers ◽  
Battery Energy Storage Systems ◽  
Battery Energy ◽  
Photovoltaic Plant

Although the literature extensively covers the development of battery chargers control strategies, a comparison of these strategies remains a literary gap. The inherent conditions (i.e., State of Health and State of Charge) of each unit in the Battery Energy Storage Systems directly influence the charger control techniques for extending battery lifetime, which makes modular battery chargers an appealing topology for this analysis. This work groups charger control strategies presented in the literature into two: Adapted SoC strategies, directly linked to the field of overstress management, and SoH strategies, which are directly linked to the field of wear-out management. The methodology for comparing the control strategies encompasses battery lifetime, charger, and photovoltaic plant models. Three distinct cases were simulated using real measure data from a solar power plant and a battery model provided by MathWorks®. The results evidence that the Capacity Fade and Energy Throughput strongly depend on the strategy. The controller action evidences the previous statement, as the strategies have different goals that are related to each field. Furthermore, this work analyses the effect of the estimation process in the action of the controller.

scholarly journals Evaluation of a home-based 7-day infection control strategy for healthcare workers following high-risk exposure to severe acute respiratory coronavirus virus 2 (SARS-CoV-2): A cohort study

2020 ◽  
pp. 1-4
Author(s):  
Carla Benea ◽  
Laura Rendon ◽  
Jesse Papenburg ◽  
Charles Frenette ◽  
Ahmed Imacoudene ◽  
...  
Keyword(s):  
High Risk ◽  
Infection Control ◽  
Control Strategy ◽  
Healthcare Workers ◽  
Control Strategies ◽  
Risk Exposure ◽  
Nasopharyngeal Swab ◽  
Home Based ◽  
Respiratory Coronavirus ◽  
Second Wave

Abstract Objective: Evidence-based infection control strategies are needed for healthcare workers (HCWs) following high-risk exposure to severe acute respiratory coronavirus virus 2 (SARS-CoV-2). In this study, we evaluated the negative predictive value (NPV) of a home-based 7-day infection control strategy. Methods: HCWs advised by their infection control or occupational health officer to self-isolate due to a high-risk SARS-CoV-2 exposure were enrolled between May and October 2020. The strategy consisted of symptom-triggered nasopharyngeal SARS-CoV-2 RNA testing from day 0 to day 7 after exposure and standardized home-based nasopharyngeal swab and saliva testing on day 7. The NPV of this strategy was calculated for (1) clinical coronavirus disease 2019 (COVID-19) diagnosis from day 8–14 after exposure, and for (2) asymptomatic SARS-CoV-2 detected by standardized nasopharyngeal swab and saliva specimens collected at days 9, 10, and 14 after exposure. Interim results are reported in the context of a second wave threatening this essential workforce. Results: Among 30 HCWs enrolled, the mean age was 31 years (SD, ±9), and 24 (80%) were female. Moreover, 3 were diagnosed with COVID-19 by day 14 after exposure (secondary attack rate, 10.0%), and all cases were detected using the 7-day infection control strategy: the NPV for subsequent clinical COVID-19 or asymptomatic SARS-CoV-2 detection by day 14 was 100.0% (95% CI, 93.1%–100.0%). Conclusions: Among HCWs with high-risk exposure to SARS-CoV-2, a home-based 7-day infection control strategy may have a high NPV for subsequent COVID-19 and asymptomatic SARS-CoV-2 detection. Ongoing data collection and data sharing are needed to improve the precision of the estimated NPV, and here we report interim results to inform infection control strategies in light of a second wave threatening this essential workforce.

Application of Combined Feedforward and Feedback Controller With Shaped Input to Benchmark Problem

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Young Joo Shin ◽  
Peter H. Meckl
Keyword(s):  
Feedback Control ◽  
Control Strategy ◽  
Control Strategies ◽  
Control Design ◽  
Single Frequency ◽  
Benchmark Problems ◽  
Control Force ◽  
Benchmark Problem ◽  
Advantages And Disadvantages ◽  
Robust Control Design

Benchmark problems have been used to evaluate the performance of a variety of robust control design methodologies by many control engineers over the past 2 decades. A benchmark is a simple but meaningful problem to highlight the advantages and disadvantages of different control strategies. This paper verifies the performance of a new control strategy, which is called combined feedforward and feedback control with shaped input (CFFS), through a benchmark problem applied to a two-mass-spring system. CFFS, which consists of feedback and feedforward controllers and shaped input, can achieve high performance with a simple controller design. This control strategy has several unique characteristics. First, the shaped input is designed to extract energy from the flexible modes, which means that a simpler feedback control design based on a rigid-body model can be used. In addition, only a single frequency must be attenuated to reduce residual vibration of both masses. Second, only the dynamics between control force and the first mass need to be considered in designing both feedback and feedforward controllers. The proposed control strategy is applied to a benchmark problem and its performance is compared with that obtained using two alternative control strategies.

Risks of post-emergence weed control strategies in sugar beet: development and application of a bio-economic model

1999 ◽  
Vol 59 (3) ◽  
pp. 283-299 ◽  
Author(s):  
A.J de Buck ◽  
H.B Schoorlemmer ◽  
G.A.A Wossink ◽  
S.R.M Janssens
Keyword(s):  
Sugar Beet ◽  
Weed Control ◽  
Economic Model ◽  
Control Strategies

Robust H2/H∞Control Strategy for Linear Markovian Jump Systems

2014 ◽  
Vol 525 ◽  
pp. 646-652
Author(s):  
Min Bian ◽  
Qing Yun Guo
Keyword(s):  
Control Strategy ◽  
State Feedback ◽  
Control Strategies ◽  
State Feedback Control ◽  
Linear Matrix ◽  
Bounded Real Lemma ◽  
Finite State ◽  
Linear State ◽  
Feasible Solutions ◽  
Jump Systems

The robust H2/<em>H</em>∞ control strategy for a class of linear continuous-time uncertain systems with randomly jumping parameters is investigated. The transition of the jumping parameters is decided by a finite-state Markov process. The uncertainties are supposed to be norm-bounded. It is desired to design a linear state feedback control strategies such that the closed-loop system satisfies H performance and minimizes the H2 norm of the system. A sufficient condition is first established on the existence of the robust H2/<em>H</em>∞controller bases on the bounded real lemma. Then the corresponding state-feedback law is given in terms of a set of linear matrix inequalities (LMIs). It is showed that this condition is equivalent to the feasible solutions problem of LMI. Furthermore, the control strategy design problem is converted into a convex optimization problem subject to LMI constraints, which can be easily solved by standard numerical software.

The Use of Damping Based Semi-Active Control Algorithms in the Mechanical Smart-Spring System

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Wander Gustavo Rocha Vieira ◽  
Fred Nitzsche ◽  
Carlos De Marqui
Keyword(s):  
Active Control ◽  
Control Algorithm ◽  
Control Strategies ◽  
Vibration Reduction ◽  
Flow Analysis ◽  
Coupled Systems ◽  
Control Technique ◽  
Control Algorithms ◽  
Control Techniques ◽  
Spring Mechanism

In recent decades, semi-active control strategies have been investigated for vibration reduction. In general, these techniques provide enhanced control performance when compared to traditional passive techniques and lower energy consumption if compared to active control techniques. In semi-active concepts, vibration attenuation is achieved by modulating inertial, stiffness, or damping properties of a dynamic system. The smart spring is a mechanical device originally employed for the effective modulation of its stiffness through the use of semi-active control strategies. This device has been successfully tested to damp aeroelastic oscillations of fixed and rotary wings. In this paper, the modeling of the smart spring mechanism is presented and two semi-active control algorithms are employed to promote vibration reduction through enhanced damping effects. The first control technique is the smart-spring resetting (SSR), which resembles resetting control techniques developed for vibration reduction of civil structures as well as the piezoelectric synchronized switch damping on short (SSDS) technique. The second control algorithm is referred to as the smart-spring inversion (SSI), which presents some similarities with the synchronized switch damping (SSD) on inductor technique previously presented in the literature of electromechanically coupled systems. The effects of the SSR and SSI control algorithms on the free and forced responses of the smart-spring are investigated in time and frequency domains. An energy flow analysis is also presented in order to explain the enhanced damping behavior when the SSI control algorithm is employed.

660MW Single Auxiliary Ultra-Supercritical Unit Main Stream’s Temperature Control Strategy Optimization Studies

2014 ◽  
Vol 909 ◽  
pp. 317-322
Author(s):  
Huan Pao Huang ◽  
Ji An Yu ◽  
Qian Su ◽  
Lei Wang
Keyword(s):  
Temperature Control ◽  
Control Strategy ◽  
Control Strategies ◽  
Dynamic Parameter ◽  
Pilot Project ◽  
Smith Predictor ◽  
Temperature Control System ◽  
Performance Requirements ◽  
And Performance ◽  
Adjustable Range

2 × 660MW ultra-supercritical units of O'Brien Power Plant are single configuration of auxiliary pilot project, due to the higher its parameters and performance requirements, it need better control strategies to ensure safe and economical operation. Against traditional cascade PID main steam’s temperature control system delaying large, this article proposed control strategy based on Smith estimated. Main steam’s temperature controlled object inert zone mathematical model can be showed by multi-volume model, and use the improved system for large inertia Smith Predictor to make dynamic parameter control systems improvements. Simulation results of the simulation machine show that: Optimization emperor steam temperature control is in an adjustable range and the policy in separate auxiliary units is feasible.

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