ABSTRACT
This paper adopts a two-stage stochastic frontier analysis framework to analyse the roles of foreign and domestic capital in the aggregate production of gross domestic product (GDP) and CO2-equivalent emissions across 36 OECD countries from 1990 to 2014. The first stage estimates a quadratic output directional distance function to derive the marginal products of foreign and domestic capital with respective to GDP and emissions. The second stage examines explanations for variations in the marginal rate of technical substitution (MRTS) of foreign and domestic capital across OECD countries. Our paper finds two important empirical evidence findings on the role of foreign capital in the aggregate production of desirable and undesirable outputs. Firstly, that foreign capital appears to be more effective than domestic capital in generating GDP and curbing CO2-equivalent emissions. We find that one standard deviation of GDP (or $2333 billion in 2011 dollars) would require $1857 billion (in 2011 dollars) of foreign capital in comparison with $4867 billion of domestic capital, ceteris paribus. On the other hand, the reduction of CO2-equivalent emissions by one standard deviation would demand $4091 billion (in 2011 dollars) of foreign capital relative to $16,539 billion of domestic capital. Second, foreign capital is more effective in reducing emissions in countries characterised by higher GDP per capita, larger population density, and higher shares of manufacturing sectors and exports.
Subject(s)
Carbon Dioxide , Organisation for Economic Co-Operation and Development , Gross Domestic Product , Internationality , Economic DevelopmentABSTRACT
The need for combined task and motion planning (CTAMP) in robotics is well known as robotic technologies become more mature. The goal of CTAMP is to determine a proper sequence of a robot's actions based on symbolic and geometric reasoning. Because of the fundamental difference in symbolic and geometric reasoning, a CTAMP system often requires an interface module between the two reasoning modules. We propose a CTAMP system in which a symbolic action sequence is generated in task planning, and each action is verified geometrically in motion planning using the off-the-shelf planners and reasoners. The approach is that a set of action models is defined with PDDL in the interface module (action library) and the required information to each planner is automatically provided by the interface module. The proposed method was successfully implemented in three simulated experiments that involve manipulation tasks. According to our findings, the proposed method is effective in responding to changes in the environment and uncertainty with errors in recognition of the environment and the robot motion control.
ABSTRACT
Artificial muscle actuators made from commercial nylon fishing lines have been recently introduced and shown as a new type of actuator with high performance. However, the actuators also exhibit significant nonlinearities, which make them difficult to control, especially in precise trajectory-tracking applications. In this article, we present a nonlinear mathematical model of a conductive supercoiled polymer (SCP) actuator driven by Joule heating for model-based feedback controls. Our efforts include modeling of the hysteresis behavior of the actuator. Based on nonlinear modeling, we design a sliding mode controller for SCP actuator-driven manipulators. The system with proposed control law is proven to be asymptotically stable using the Lyapunov theory. The control performance of the proposed method is evaluated experimentally and compared with that of a proportional-integral-derivative (PID) controller through one-degree-of-freedom SCP actuator-driven manipulators. Experimental results show that the proposed controller's performance is superior to that of a PID controller, such as the tracking errors are nearly 10 times smaller compared with those of a PID controller, and it is more robust to external disturbances such as sensor noise and actuator modeling error.
