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Regression analysis using a blending type spline construction
(Peer reviewed; Chapter; Bokkapittel, 2017-10-18)
Regression analysis allows us to track the dynamics of change in measured data and to investigate their properties. A sufficiently good model allows us to predict the behavior of dependent variables with higher accuracy, and to propose a more precise data generation hypothesis. By using polynomial approximation for big data sets with complex dependencies we get piecewise smooth functions. One way ...
Thyristor based short circuit current injection in isolated grids
(Peer reviewed; Chapter; Bokkapittel, 2017-02-16)
This paper proposes a thyristor based short circuit current injector for providing short circuit current in isolated and weak grids, where sufficient fault current to trigger circuit breakers may not be available. This will allow the use of conventional miniature circuit breakers, which requires high fault current for instantaneous tripping. The method has been validated through experiments.
Welding Certification for Autonomous Robotized Welding
(Chapter; Bokkapittel, 2016-10-23)
The increased production of more and more complex products challenges the accuracy of manual welding, and increase the time it takes to program automatic welding systems. The main objective for the article is to explore if current regulations and standards are able to accommodate the shift from automatic welding to autonomous welding systems. To do this, the most current and applicable standards ...
A decision-support model for operational planning of surface coal mining considering equipment failure
(Peer reviewed; Conference object; Konferansebidrag; Bokkapittel; Chapter, 2016)
This paper presents a decision-support model aiming, primarily, at maximizing the productivity of surface coal mining activities through operational planning and management. The model is formulated based upon mixed integer programming, and it determines the optimal production plan of the shovels and allocation plan of the haul trucks in order to minimize operational cost, fuel consumption as well ...
A Goal Programming Approach for Green Supply Chain Network Optimization
(Chapter; Bokkapittel, 2016-10)
Green supply chain management has been focused by both academicians and practitioners in recent years due to the increased public awareness on environmental problems and sustainable development. In this paper, a decision aided model for green supply chain network design and optimization is proposed to justify both economic and environmental performance in an optimal fashion. The model is formulated ...
A Trade-off Model for Green Supply Chain Design: An Efficiency-versus-Emission Analysis
(Peer reviewed; Chapter; Bokkapittel, 2018-04-09)
—With the growing concern of climate change and global warming, the reduction on carbon emissions of supply chain activities have been increasingly focused by both academics and corporates in the last two decades. The increased public awareness on sustainability and stricter environmental policies together enforce the companies to rethink their practices in supply chain design and operations in an ...
Quaternion guidance and control of quadrotor
(Peer reviewed; Konferansebidrag; Bokkapittel; Conference object; Chapter, 2017-07-27)
This paper addresses the problem of trajectory tracking for underactuated quadrotors. A quaternion based guidance law is proposed which feeds into an attitude control system based on a PD+ control law. The desired attitude from the guidance law is defined such that the attitude control system tries to align the position error along the axis of the translational actuator. Simulation results are ...
Path-following in three dimensions using quaternions for a fixed-wing UAV
(Peer reviewed; Konferansebidrag; Bokkapittel; Conference object; Chapter, 2017-08-08)
This paper presents a three dimensional guidance strategy for fixed-wing UAVs using quaternions. The algorithm is based on constructing two quaternions, one which makes the UAV fly towards the path and one that makes the UAV follow the path. These two quaternions are then blended together such that the path-following objective is reached. The guidance algorithm is applied to a simple kinematic model ...
Approaches to learning of linear algebra among engineering students
(Peer reviewed; Bok; Book; Bokkapittel; Chapter, 2017-02)
The present paper investigates engineering students` own descriptions of what they mean by learning of linear algebra and how they know that they have learned something. I seek to extract keywords from engineering students` descriptions of learning of this discipline by drawing on grounded theory techniques and classifying the answers in conceptual and procedural approaches. By this, both detailed ...
Improving the Decision-making of Reverse Logistics Network Design Part II: An Improved Scenario-based Solution Method and Numerical Experimentation
(Peer reviewed; Chapter; Bokkapittel, 2018-02-11)
The study of the network design problems related to reverse supply chain and reverse logistics is of great interest for both academicians and practitioners due to its important role for a sustainable society. However, reverse logistics network design is a complex decision-making problem that involves several interactive factors and faces many uncertainties. Thus, in order to improve the reverse ...