Search results for "400"
showing 10 items of 1272 documents
Development of net energy ratio and emission factor for quad-generation pathways
2014
Published version of an article in the journal: Energy Systems. Also available from the publisher at: http://dx.doi.org/10.1007/s12667-014-0126-4 The conversion of biomass to four different outputs via gasification is a renewable technology that could reduce the use of fossil fuels and greenhouse gas (GHG) emissions. This study investigates the energy aspects for a new concept of biomass based quad-generation plant producing power, heat, methanol and methane. Circulating fluidized bed gasifier and the gas technology institute (GTI) gasifier technologies are used for this quad-generation process. Two different biomass feedstocks are considered in this study. The net energy ratio for six diff…
Effects of nitrogen enrichment on zooplankton biomass and N:P recycling ratios across a DOC gradient in northern-latitude lakes
2021
AbstractWe used data from whole-lake studies to assess how changes in food quantity (phytoplankton biomass) and quality (phytoplankton community composition, seston C:P and N:P) with N fertilization affect zooplankton biomass, community composition and C:N:P stoichiometry, and their N:P recycling ratio along a gradient in lake DOC concentrations. We found that despite major differences in phytoplankton biomass with DOC (unimodal distributions, especially with N fertilization), no major differences in zooplankton biomass were detectable. Instead, phytoplankton to zooplankton biomass ratios were high, especially at intermediate DOC and after N fertilization, implying low trophic transfer effi…
Unified understanding of intrinsic and extrinsic controls of dissolved organic carbon reactivity in aquatic ecosystems
2022
Despite our growing understanding of the global carbon cycle, scientific consensus on the drivers and mechanisms that control dissolved organic carbon (DOC) turnover in aquatic systems is lacking, hampered by the mismatch between research that approaches DOC reactivity from either intrinsic (inherent chemical properties) or extrinsic (environmental context) perspectives. Here we propose a conceptual view of DOC reactivity in which the combination of intrinsic and extrinsic factors controls turnover rates and determines which reactions will occur. We review three major types of reactions (biological, photochemical, and flocculation) from an intrinsic chemical perspective and further define t…
Ant colony optimisation for planning safe escape routes
2013
Published version of a chapter from the volume: Recent Trends in Applied Artificial Intelligence. Also available on SpringerLink: http://dx.doi.org/10.1007/978-3-642-38577-3_6 An emergency requiring evacuation is a chaotic event filled with uncertainties both for the people affected and rescuers. The evacuees are often left to themselves for navigation to the escape area. The chaotic situation increases when a predefined escape route is blocked by a hazard, and there is a need to re-think which escape route is safest. This paper addresses automatically finding the safest escape route in emergency situations in large buildings or ships with imperfect knowledge of the hazards. The proposed so…
What shapes Norwegian wind power policy? Analysing the constructing forces of policymaking and emerging questions of energy justice
2021
Abstract This paper employs an assemblage theoretical approach to analyse how Norwegian land-based wind power policies are constructed over time and what forces dominate and resist wind power policy development. The entanglement of policies, technology deployment and (lack of) social acceptance emphasizes the need to critically question what and who influence the construction of energy transition policies and how and what concerns are left out, especially in relation to the tenets of energy justice. We find that wind power policies are primarily influenced by energy authorities, developers and interest organizations, furthering arguments of climate concerns, energy security and economic opp…
The Identification of Convex Function on Riemannian Manifold
2014
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://10.1155/2014/273514 The necessary and sufficient condition of convex function is significant in nonlinear convex programming. This paper presents the identification of convex function on Riemannian manifold by use of Penot generalized directional derivative and the Clarke generalized gradient. This paper also presents a method for judging whether a point is the global minimum point in the inequality constraints. Our objective here is to extend the content and proof the necessary and sufficient condition of convex function to Riemannian manifolds. © 2014 Li Zou e…
Model reduction of fuzzy logic systems
2014
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2014/874530 This paper deals with the problem of l 2 - l ∞ model reduction for continuous-time nonlinear uncertain systems. The approach of the construction of a reduced-order model is presented for high-order nonlinear uncertain systems described by the T-S fuzzy systems, which not only approximates the original high-order system well with an l 2 - l ∞ error performance level γ but also translates it into a linear lower-dimensional system. Then, the model approximation is converted into a convex optimization problem by using a linearization p…
Sampling based average classifier fusion
2014
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2014/369613 Classifier fusion is used to combine multiple classification decisions and improve classification performance. While various classifier fusion algorithms have been proposed in literature, average fusion is almost always selected as the baseline for comparison. Little is done on exploring the potential of average fusion and proposing a better baseline. In this paper we empirically investigate the behavior of soft labels and classifiers in average fusion. As a result, we find that; by proper sampling of soft labels and classifiers, t…
The public procurement of information systems: dialectics in requirements specification
2017
When acquiring information systems, public entities face a dilemma. On the one hand, they want to procure the system that best suits their needs, which often requires lengthy dialogues with vendors. At the same time, they are restricted by government regulations that mandate limited dialogue in the interests of transparency and equal opportunities for all vendors. To examine how public entities deal with this, we followed three procurement projects in Norway. We show that this dilemma manifests itself as a dialectic between the thesis of getting the system requirements right and the antithesis of strictly adhering to regulations. Public entities search for a resolution of this dialectic thr…
Observer-Based Robust Control for Hydraulic Velocity Control System
2013
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2013/689132 Open access This paper investigates the problems of robust stabilization and robust control for the secondary component speed control system with parameters uncertainty and load disturbance. The aim is to enhance the control performance of hydraulic system based on Common Pressure Rail (CPR). Firstly, a mathematical model is presented to describe the hydraulic control system. Then a novel observer is proposed, and an observed-based control strategy is designed such that the closed-loop system is asymptotically stable and satisfies …