52,027 research outputs found
Modeling and Solving a Resource Allocation Problem with Soft Constraint Techniques
We study a resource allocation problem, which is a central piece of a real-world crew scheduling problem. We first formulate the problem as a hybrid soft constraint satisfaction and optimization problem and show that its worst-case complexity is NP-complete. We then propose and study a set of decision and optimization modeling schemes for the problem. We consider the expressiveness of these modeling schemes for the problem. We consider the expressiveness of these modeling methods. Specifically, we experimentally investigate how these modeling schemes interplay with the best existing systematic search and local search methods. Our experimental results show that soft constraint techniques can be effective on large resource allocation problem instances, and an optimization approach is more efficient than a model checking approach based on decision models
Beamforming Techniques for Non-Orthogonal Multiple Access in 5G Cellular Networks
In this paper, we develop various beamforming techniques for downlink
transmission for multiple-input single-output (MISO) non-orthogonal multiple
access (NOMA) systems. First, a beamforming approach with perfect channel state
information (CSI) is investigated to provide the required quality of service
(QoS) for all users. Taylor series approximation and semidefinite relaxation
(SDR) techniques are employed to reformulate the original non-convex power
minimization problem to a tractable one. Further, a fairness-based beamforming
approach is proposed through a max-min formulation to maintain fairness between
users. Next, we consider a robust scheme by incorporating channel
uncertainties, where the transmit power is minimized while satisfying the
outage probability requirement at each user. Through exploiting the SDR
approach, the original non-convex problem is reformulated in a linear matrix
inequality (LMI) form to obtain the optimal solution. Numerical results
demonstrate that the robust scheme can achieve better performance compared to
the non-robust scheme in terms of the rate satisfaction ratio. Further,
simulation results confirm that NOMA consumes a little over half transmit power
needed by OMA for the same data rate requirements. Hence, NOMA has the
potential to significantly improve the system performance in terms of transmit
power consumption in future 5G networks and beyond.Comment: accepted to publish in IEEE Transactions on Vehicular Technolog
Allocating educational resources through happiness maximization and traditional CSP approach
This is an electronic version of the paper presented at the 4th International Conference on Software and Data Technologies, held in Sofia on 2009An instance of an Educational Resources Allocation (ERA) problem is the distribution of a set of students
in different laboratories. This can be a complex and dynamic problem if non-quantitative considerations (i.e.
how close the final allocation is to the student preferences or desires) are involved in the decision process. Traditionally,
different approaches based on Constraint-Satisfaction techniques and Multi-agent negotiation have
been applied to the general problem of Resource Allocation. This paper shows how a Multi-agent approach
can be used to model and simulate the assignment of sets of students to several predefined laboratories, by
using their preferences to guide the allocation process. This approach aims at finding new solutions that try
to satisfy individual student needs with no knowledge about the general allocation problem. The paper shows
some experimental results and a comparison, between a CSP-based solution modeled in CHOCO, a CSP
Java-based library, and a Multi-agent model implemented using MASON, a multi-agent simulation platform.This work has been supported by research projects
TIN2007-65989 and TIN2007-64718. We also thank
IBM for its support to the Linux Reference Cente
A Complete Solver for Constraint Games
Game Theory studies situations in which multiple agents having conflicting
objectives have to reach a collective decision. The question of a compact
representation language for agents utility function is of crucial importance
since the classical representation of a -players game is given by a
-dimensional matrix of exponential size for each player. In this paper we
use the framework of Constraint Games in which CSP are used to represent
utilities. Constraint Programming --including global constraints-- allows to
easily give a compact and elegant model to many useful games. Constraint Games
come in two flavors: Constraint Satisfaction Games and Constraint Optimization
Games, the first one using satisfaction to define boolean utilities. In
addition to multimatrix games, it is also possible to model more complex games
where hard constraints forbid certain situations. In this paper we study
complete search techniques and show that our solver using the compact
representation of Constraint Games is faster than the classical game solver
Gambit by one to two orders of magnitude.Comment: 17 page
Human-Machine Collaborative Optimization via Apprenticeship Scheduling
Coordinating agents to complete a set of tasks with intercoupled temporal and
resource constraints is computationally challenging, yet human domain experts
can solve these difficult scheduling problems using paradigms learned through
years of apprenticeship. A process for manually codifying this domain knowledge
within a computational framework is necessary to scale beyond the
``single-expert, single-trainee" apprenticeship model. However, human domain
experts often have difficulty describing their decision-making processes,
causing the codification of this knowledge to become laborious. We propose a
new approach for capturing domain-expert heuristics through a pairwise ranking
formulation. Our approach is model-free and does not require enumerating or
iterating through a large state space. We empirically demonstrate that this
approach accurately learns multifaceted heuristics on a synthetic data set
incorporating job-shop scheduling and vehicle routing problems, as well as on
two real-world data sets consisting of demonstrations of experts solving a
weapon-to-target assignment problem and a hospital resource allocation problem.
We also demonstrate that policies learned from human scheduling demonstration
via apprenticeship learning can substantially improve the efficiency of a
branch-and-bound search for an optimal schedule. We employ this human-machine
collaborative optimization technique on a variant of the weapon-to-target
assignment problem. We demonstrate that this technique generates solutions
substantially superior to those produced by human domain experts at a rate up
to 9.5 times faster than an optimization approach and can be applied to
optimally solve problems twice as complex as those solved by a human
demonstrator.Comment: Portions of this paper were published in the Proceedings of the
International Joint Conference on Artificial Intelligence (IJCAI) in 2016 and
in the Proceedings of Robotics: Science and Systems (RSS) in 2016. The paper
consists of 50 pages with 11 figures and 4 table
Models for robust resource allocation in project scheduling.
The vast majority of resource-constrained project scheduling efforts assumes complete information about the scheduling problem to be solved and a static deterministic environment within which the pre-computed baseline schedule will be executed. In reality, however, project activities are subject to considerable uncertainty which generally leads to numerous schedule disruptions. In this paper, we present a resource allocation model that protects the makespan of a given baseline schedule against activity duration variability. A branch-and-bound algorithm is developed that solves the proposed robust resource allocation problem in exact and approximate formulations. The procedure relies on constraint propagation during its search. We report on computational results obtained on a set of benchmark problems.Model; Resource allocation; Scheduling;
Stability and resource allocation in project planning.
The majority of resource-constrained project scheduling efforts assumes perfect information about the scheduling problem to be solved and a static deterministic environment within which the pre-computed baseline schedule is executed. In reality, project activities are subject to considerable uncertainty, which generally leads to numerous schedule disruptions. In this paper, we present a resource allocation model that protects a given baseline schedule against activity duration variability. A branch-and-bound algorithm is developed that solves the proposed resource allocation problem. We report on computational results obtained on a set of benchmark problems.Constraint satisfaction; Information; Model; Planning; Problems; Project management; Project planning; Project scheduling; Resource allocati; Scheduling; Stability; Uncertainty; Variability;
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