Norwegian University of Science and Technology

About: Norwegian University of Science and Technology is a education organization based out in Trondheim, Norway. It is known for research contribution in the topics: Population & Computer science. The organization has 23182 authors who have published 68917 publications receiving 1929313 citations. The organization is also known as: NTNU & Norwegian University of Science and Technology (NTNU).

Constrained nonlinear control allocation with singularity avoidance using sequential quadratic programming

Abstract: Control allocation problems can be formulated as optimization problems, where the objective is typically to minimize the use of control effort (or power) subject to actuator rate and position constraints, and other operational constraints. Here we consider the additional objective of singularity avoidance, which is essential to avoid loss of controllability in some applications, leading to a nonconvex nonlinear program. We suggest a sequential quadratic programming approach, solving at each sample a convex quadratic program approximating the nonlinear program. The method is illustrated by simulated maneuvers for a marine vessel equipped with azimuth thrusters. The example indicates reduced power consumption and increased maneuverability as a consequence of the singularity-avoidance.

Carbon emission of global construction sector

Abstract: The construction sector delivers the infrastructure and buildings to the society by consumption large amount of unrenewable energy. Consequently, this consumption causes the large emission of CO2. This paper explores and compares the level of CO2 emission caused by the construction activities globally by using the world environmental input-output table 2009. It analyses CO2 emission of construction sector in 40 countries, considering 26 kinds of energy use and non-energy use. Results indicate: 1) the total CO2 emission of the global construction sector was 5.7 billion tons in 2009, contributing 23% of the total CO2 emissions produced by the global economics activities. 94% of the total CO2 from the global construction sector are indirect emission. 2) Gasoline, diesel, other petroleum products and light fuel oil are four main energy sources for direct CO2 emission of global construction sector. The indirect CO2 emission mainly stems from hard coal, nature gas, and non-energy use. 3) The emerging economies cause nearly 60% of the global construction sector total CO2 emission. China is the largest contributor. Moreover, the intensities of construction sector’s direct and indirect CO2 emission in the developing countries are larger than the value in the developed countries. Therefore, promoting the development and use of the low embodied carbon building material and services, the energy efficiency of construction machines, as well as the renewable energy use are identified as three main pivotal opportunities to reduce the carbon emissions of the construction sector.

Why did my car just do that? Explaining semi-autonomous driving actions to improve driver understanding, trust, and performance

Abstract: This study explores, in the context of semi-autonomous driving, how the content of the verbalized message accompanying the car’s autonomous action affects the driver’s attitude and safety performance. Using a driving simulator with an auto-braking function, we tested different messages that provided advance explanation of the car’s imminent autonomous action. Messages providing only “how” information describing actions (e.g., “The car is braking”) led to poor driving performance, whereas “why” information describing reasoning for actions (e.g., “Obstacle ahead”) was preferred by drivers and led to better driving performance. Providing both “how and why” resulted in the safest driving performance but increased negative feelings in drivers. These results suggest that, to increase overall safety, car makers need to attend not only to the design of autonomous actions but also to the right way to explain these actions to the drivers.