338 research outputs found
A framework for modelling, simulation and control of integrated urban wastewater system
This paper is concerned with the integrated modelling, and control of urban wastewater systems (UWS) comprising the wastewater treatment plants (WTP), receiving waters (river) and the sewer networks. A unified framework is developed and simple models are used and implemented in Matlab/Simulink to produce a toolbox. Novel linear and nonlinear control structures are then proposed to design integrated control systems to improve the river water quality. A case study is simulated and simulation results are presented to demonstrate the possible improvement that can be achieved using a holistic integrated control system approac
Mixed-integer-linear-programming-based energy management system for hybrid PV-wind-battery microgrids: Modeling, design, and experimental verification
© 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksMicrogrids are energy systems that aggregate distributed energy resources, loads, and power electronics devices in a stable and balanced way. They rely on energy management systems to schedule optimally the distributed energy resources. Conventionally, many scheduling problems have been solved by using complex algorithms that, even so, do not consider the operation of the distributed energy resources. This paper presents the modeling and design of a modular energy management system and its integration to a grid-connected battery-based microgrid. The scheduling model is a power generation-side strategy, defined as a general mixed-integer linear programming by taking into account two stages for proper charging of the storage units. This model is considered as a deterministic problem that aims to minimize operating costs and promote self-consumption based on 24-hour ahead forecast data. The operation of the microgrid is complemented with a supervisory control stage that compensates any mismatch between the offline scheduling process and the real time microgrid operation. The proposal has been tested experimentally in a hybrid microgrid at the Microgrid Research Laboratory, Aalborg University.Peer ReviewedPostprint (author's final draft
Smith-Purcell radiation emission in aperiodic arrays
We study the Smith-Purcell light emission produced by electrons moving parallel to linear aperiodic particle
arrays. This constitutes a generalization of this type of phenomenon from periodic to aperiodic structures. As in the
periodic case, the emission is found to exhibit intense features in its angular and frequency distributions, associated
with the condition of constructive interference between the contributions arising from different particles in the
array. This condition can also be expressed in terms of momentum conservation involving reciprocal wave-vector
transfers from the array. We consider two examples of quasiperiodic and hyperuniform aperiodic arrays that
allow us to illustrate this idea. Our study provides insight into the interaction of fast electrons with aperiodic
arrays characterized by strong features in reciprocal space, which dominate the electron-array coupling.Postprint (published version
Measuring Spatial Subdivisions in Urban Mobility with Mobile Phone Data
Urban population grows constantly. By 2050 two thirds of the world population
will reside in urban areas. This growth is faster and more complex than the
ability of cities to measure and plan for their sustainability. To understand
what makes a city inclusive for all, we define a methodology to identify and
characterize spatial subdivisions: areas with over- and under-representation of
specific population groups, named hot and cold spots respectively. Using
aggregated mobile phone data, we apply this methodology to the city of
Barcelona to assess the mobility of three groups of people: women, elders, and
tourists. We find that, within the three groups, cold spots have a lower
diversity of amenities and services than hot spots. Also, cold spots of women
and tourists tend to have lower population income. These insights apply to the
floating population of Barcelona, thus augmenting the scope of how
inclusiveness can be analyzed in the city.Comment: 10 pages, 10 figures. To be presented at the Data Science for Social
Good workshop at The Web Conference 202
Data Portraits and Intermediary Topics: Encouraging Exploration of Politically Diverse Profiles
In micro-blogging platforms, people connect and interact with others.
However, due to cognitive biases, they tend to interact with like-minded people
and read agreeable information only. Many efforts to make people connect with
those who think differently have not worked well. In this paper, we
hypothesize, first, that previous approaches have not worked because they have
been direct -- they have tried to explicitly connect people with those having
opposing views on sensitive issues. Second, that neither recommendation or
presentation of information by themselves are enough to encourage behavioral
change. We propose a platform that mixes a recommender algorithm and a
visualization-based user interface to explore recommendations. It recommends
politically diverse profiles in terms of distance of latent topics, and
displays those recommendations in a visual representation of each user's
personal content. We performed an "in the wild" evaluation of this platform,
and found that people explored more recommendations when using a biased
algorithm instead of ours. In line with our hypothesis, we also found that the
mixture of our recommender algorithm and our user interface, allowed
politically interested users to exhibit an unbiased exploration of the
recommended profiles. Finally, our results contribute insights in two aspects:
first, which individual differences are important when designing platforms
aimed at behavioral change; and second, which algorithms and user interfaces
should be mixed to help users avoid cognitive mechanisms that lead to biased
behavior.Comment: 12 pages, 7 figures. To be presented at ACM Intelligent User
Interfaces 201
- …