28,198 research outputs found
Integrated Resource Planning for a Chinese Urban Development
Urban areas manage vast quantities of energy, water and waste resources. In order to minimise the cost and
environmental impact, optimisation modelling is often used in the design and operation of these systems. However,
traditional modelling approaches only consider the energy, water and waste sectors in isolation. This approach
neglects the synergies possible between these systems whereby outputs from one system form an input to another,
and hence sets an upper bound on economic and environmental impact minimisation. We formulate a mixed integer
linear programming (MILP) model which takes a ‘systems-of-infrastructure systems’ approach to show how resource
consumption can be reduced. The model takes as inputs possible resource conversion and transportation infrastructure
and resources, and resource demands, and returns the optimal infrastructure choice and layout. The model is called
PRaQ because it models ‘processes, resources and qualities.’ We apply the model to the design of a new urban
development in China for three scenarios of various levels of resource integration. Results are still to be obtained
Interference-Aware Decoupled Cell Association in Device-to-Device based 5G Networks
Cell association in cellular networks is an important aspect that impacts
network capacity and eventually quality of experience. The scope of this work
is to investigate the different and generalized cell association (CAS)
strategies for Device-to-Device (D2D) communications in a cellular network
infrastructure. To realize this, we optimize D2D-based cell association by
using the notion of uplink and downlink decoupling that was proven to offer
significant performance gains. We propose an integer linear programming (ILP)
optimization framework to achieve efficient D2D cell association that minimizes
the interference caused by D2D devices onto cellular communications in the
uplink as well as improve the D2D resource utilization efficiency. Simulation
results based on Vodafone's LTE field trial network in a dense urban scenario
highlight the performance gains and render this proposal a candidate design
approach for future 5G networks.Comment: 5 pages, 5 figures. Accepted in IEEE VTC spring 201
An optimization model for line planning and timetabling in automated urban metro subway networks
In this paper we present a Mixed Integer Nonlinear Programming model that we
developed as part of a pilot study requested by the R&D company Metrolab in
order to design tools for finding solutions for line planning and timetable
situations in automated urban metro subway networks. Our model incorporates
important factors in public transportation systems from both, a cost-oriented
and a passenger-oriented perspective, as time-dependent demands, interchange
stations, short-turns and technical features of the trains in use. The incoming
flows of passengers are modeled by means of piecewise linear demand functions
which are parameterized in terms of arrival rates and bulk arrivals. Decisions
about frequencies, train capacities, short-turning and timetables for a given
planning horizon are jointly integrated to be optimized in our model. Finally,
a novel Math-Heuristic approach is proposed to solve the problem. The results
of extensive computational experiments are reported to show its applicability
and effectiveness to handle real-world subway networksComment: 30 pages, 6 figures, 9 table
Spatial optimization for land use allocation: accounting for sustainability concerns
Land-use allocation has long been an important area of research in regional science. Land-use patterns are fundamental to the functions of the biosphere, creating interactions that have substantial impacts on the environment. The spatial arrangement of land uses therefore has implications for activity and travel within a region. Balancing development, economic growth, social interaction, and the protection of the natural environment is at the heart of long-term sustainability. Since land-use patterns are spatially explicit in nature, planning and management necessarily must integrate geographical information system and spatial optimization in meaningful ways if efficiency goals and objectives are to be achieved. This article reviews spatial optimization approaches that have been relied upon to support land-use planning. Characteristics of sustainable land use, particularly compactness, contiguity, and compatibility, are discussed and how spatial optimization techniques have addressed these characteristics are detailed. In particular, objectives and constraints in spatial optimization approaches are examined
An (MI)LP-based Primal Heuristic for 3-Architecture Connected Facility Location in Urban Access Network Design
We investigate the 3-architecture Connected Facility Location Problem arising
in the design of urban telecommunication access networks. We propose an
original optimization model for the problem that includes additional variables
and constraints to take into account wireless signal coverage. Since the
problem can prove challenging even for modern state-of-the art optimization
solvers, we propose to solve it by an original primal heuristic which combines
a probabilistic fixing procedure, guided by peculiar Linear Programming
relaxations, with an exact MIP heuristic, based on a very large neighborhood
search. Computational experiments on a set of realistic instances show that our
heuristic can find solutions associated with much lower optimality gaps than a
state-of-the-art solver.Comment: This is the authors' final version of the paper published in:
Squillero G., Burelli P. (eds), EvoApplications 2016: Applications of
Evolutionary Computation, LNCS 9597, pp. 283-298, 2016. DOI:
10.1007/978-3-319-31204-0_19. The final publication is available at Springer
via http://dx.doi.org/10.1007/978-3-319-31204-0_1
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