Detecting price links in the world cotton market

The authors examine the degree to which international cotton prices are linked and test whether such links have improved over the past decade. They conclude that the degree of linkage has improved over the past decade, in the short run largely as the result of short-run price transmission -- and to a lesser extent because of long-run comovement. Improvements in information technology have made it much easier for information about demand to be disseminated across markets, so changes in cotton prices attributable to a price shock in one place are soon transmitted to prices in other places. Moreover, many countries have liberalized their cotton subsectors, and in some countries the government's role has changed substantially. In East Africa, for example, cotton marketing and trade was handled entirely by government parastatals. Now Tanzania, Uganda, and Zimbabwe have liberalized their marketing and trade regimes, to varying degrees. In the former Soviet Union (FSU) cotton shipped from Central Asia to other parts of the FSU were considered part of domestic trade. Now cotton exports from Uzbekistan are the most important component of that country's foreign trade. With such changes, one should expect cotton prices to converge somewhat more in the long run. Price links between West Africa and Central Asia are much greater than between the United States and other markets -- in part because most West African and Central Asian cotton is exported, compared with only 40 percent of U.S. cotton (and 60 percent of Greek cotton). Prices in countries that export most of their cotton are more likely to converge than prices in countries where prices are subject to both domestic and international demand conditions. To improve price risk management, there should be future contracts other than those traded on the New York Cotton Exchange, which mostly serves domestic U.S. needs and is not used extensively by non-U.S. hedgers and speculators.Economic Theory&Research,Markets and Market Access,Environmental Economics&Policies,Payment Systems&Infrastructure,General Technology,Markets and Market Access,Environmental Economics&Policies,Economic Theory&Research,General Technology,Access to Markets

Development of LoRaWAN-based IoT system for water quality monitoring in rural areas

This article delineates the design and deployment of an innovative real-time water quality monitoring system tailored for rural regions, focusing on monitoring the water resource quality parameters. We propose a solar-powered, waterproof, portable, and Internet of Things (IoT)-enabled solution that leverages Long Range Wide Area Network (LoRaWAN) technology. Central to this system is a sophisticated LoRa node outfitted with an array of sensors for capturing key water parameters, such as pH, total dissolved solids, turbidity and temperature. A conjunction of an Arduino microcontroller-based board and a LoRa shield facilitates real-time data capture and transmission to a LoRaWAN gateway. The acquired data is transmitted to The Things Network server, which is seamlessly integrated with a ThingSpeak web-based IoT server and ThingView mobile applications. We incorporate a solar cell with a solar shield to ensure sustainable energy provision for powering the entire system through a rechargeable battery. This allows users to access vital water quality information online simultaneously and continuously in real-time. As a testament to its robustness, the system was empirically tested at Gambang Lake to demonstrate its effectiveness, functionality, buoyancy, and waterproof capabilities. We further validated the results by comparing them with laboratory sample analysis findings. Experimental evaluations confirmed the system's reliability, as evidenced by the strong agreement between the water conditions measured using our solution and those obtained from laboratory instruments. Moreover, our system efficiently and remotely updated data across multiple IoT platforms using the LoRa radio interface over the LoRaWAN gateway

A comprehensive state-of-the-art on control of industrial articulated robots

Incredible applications of robotic manipulators especially in the industrial sector have drawn attention to substitute classical control techniques with more sophisticated intelligent approaches. This, consequently, has motivated robotics community to formulate a multi-disciplinary domain of 'robot control'. Highlighting the authors' contributions in this domain, this paper presents a systematic review of control strategies for multi-Degree Of Freedom (DOF) robotic manipulators. Trivial linear approach, i.e. Proportional-Integral-Derivative (PID) control is briefly commented. Given the fact that a manipulator has a complex structure because of associated nonlinear dynamics and uncertain parameters, robust and nonlinear control techniques have been discussed in detail. These mainly include Computed Torque Control (CTC), Sliding Mode Control (SMC), Disturbance Observer Based Control (DOBC), Model Predictive Control (MPC), Linear Quadratic Regulator (LQR), H∞ control and Passivity Based Control (PBC). With a tabulated pros and cons of each of these techniques, it is expected that the survey will directly boost cutting-edge research on the subject topic by facilitating engineers, researchers and industrial-interns to realize control laws for sophisticated applications that demand accuracy, precision, repeatability, mass production and quality

Optimal v/s robust control: A study and comparison for articulated manipulator

Highly nonlinear and coupled dynamics of a robotic manipulator demands sophisticated control strategies. These strategies must have the ability to handle the uncertainties and external disturbances that can significantly deviate the system from its desired response. Considering a 6 Degree Of Freedom (DOF) serial robotic manipulator, this paper presents the design and realisation of Linear Quadratic Regulator (LQR) and Variable Structure Control (VSC) which are respectively optimal and robust control strategies. The novelty of the present research lies in the hardware implementation of both strategies on an in-house developed AU-Tonomous Articulated Robotic Educational Platform (AUTAREP). The platform is subjected to various test inputs to characterise the tracking performance of the derived control laws. The comparative results demonstrate that VSC outperforms than LQR