Carleton University

About: Carleton University is a education organization based out in Ottawa, Ontario, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 15852 authors who have published 39650 publications receiving 1106610 citations.

A model-data comparison of gross primary productivity: Results from the North American Carbon Program site synthesis

Abstract: [1] Accurately simulating gross primary productivity (GPP) in terrestrial ecosystem models is critical because errors in simulated GPP propagate through the model to introduce additional errors in simulated biomass and other fluxes. We evaluated simulated, daily average GPP from 26 models against estimated GPP at 39 eddy covariance flux tower sites across the United States and Canada. None of the models in this study match estimated GPP within observed uncertainty. On average, models overestimate GPP in winter, spring, and fall, and underestimate GPP in summer. Models overpredicted GPP under dry conditions and for temperatures below 0°C. Improvements in simulated soil moisture and ecosystem response to drought or humidity stress will improve simulated GPP under dry conditions. Adding a low-temperature response to shut down GPP for temperatures below 0°C will reduce the positive bias in winter, spring, and fall and improve simulated phenology. The negative bias in summer and poor overall performance resulted from mismatches between simulated and observed light use efficiency (LUE). Improving simulated GPP requires better leaf-to-canopy scaling and better values of model parameters that control the maximum potential GPP, such asemax (LUE), Vcmax (unstressed Rubisco catalytic capacity) or Jmax (the maximum electron transport rate).

Securing Indigenous politics: A critique of the vulnerability and adaptation approach to the human dimensions of climate change in the Canadian Arctic

Abstract: Over the past decade research examining the human dimensions of climatic change in the Arctic has expanded significantly and has become the dominant framework through which the relations between northern peoples and climatic change are understood by scholars, policy makers, political leaders, and the media. This paper critically examines the assumptions, exclusions, and orientations that characterize this broad literature, and suggests revising and expanding the terms upon which it is carried out. It focuses in particular on the exclusion of colonialism from the study of human vulnerability and adaptation to climatic change, the framing of Indigenous peoples and communities in terms of the local and the traditional, and the ways in which efforts to improve the lives of northern Indigenous peoples risk perpetuating colonial relations. The paper argues that these exclusions and orientations lead scholars to systematically overlook the immense importance of resource extraction and shipping as human dimensions of climatic change in the Canadian Arctic, and it examines the implications of such oversights.

Teleoperation of a robot manipulator using a vision-based human-robot interface

Abstract: Remote teleoperation of a robot manipulator by a human operator is often necessary in unstructured dynamic environments when human presence at the robot site is undesirable. Mechanical and other contacting interfaces used in teleoperation require unnatural human motions for object manipulation tasks or they may hinder human motion. Previous vision-based approaches have used only a few degrees of freedom for hand motion and have required hand motions that are unnatural for object manipulation tasks. This paper presents a noncontacting vision-based method of robot teleoperation that allows a human operator to communicate simultaneous six-degree-of-freedom motion tasks to a robot manipulator by having the operator perform the three-dimensional human hand-arm motion that would naturally be used to complete an object manipulation task. A vision-based human-robot interface is used for communication of human motion to the robot and for feedback of the robot motion and environment to the human operator. Teleoperation under operator position control was performed with high accuracy in object placement on a target. Semi-autonomous traded and shared control using robot-vision guidance aided in achieving a more accurate positioning and orientation of the end-effector for object gripping tasks.

Performance of pile-up mitigation techniques for jets in pp collisions at √s = 8 TeV using the ATLAS detector

Abstract: The large rate of multiple simultaneous protonproton interactions, or pile-up, generated by the Large Hadron Collider in Run 1 required the development of many new techniques to mitigate the advers ...