ITIL is a large collection of best practices, tools and methods used in the management and handling of IT services. It's composed of five books related to the most important IT management fields. In this paper, we...
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ISBN:
(纸本)9781467391870
ITIL is a large collection of best practices, tools and methods used in the management and handling of IT services. It's composed of five books related to the most important IT management fields. In this paper, we will place the emphasis on the Service Operation field in ITIL and more precisely, on the incident management process used for managing the life cycle of IT incidents. The main idea is to find a solution for an automated optimal planning of interventions in the incident management process. Indeed, despite the number of software solutions for incident management process, intervention planning is still a manual task due to the high complexity of its automation. In this paper, we propose two solutions for automated optimal planning of interventions in the incident management. The first is inspired by the vehicle routing problems and the second is inspired by the constraint-based problems. Eventually, we will compare between the results of these two solution.
Alternative splicing is a key process in post-transcriptional regulation, by which different mature RNA can be obtained from the same premessenger RNA. The resulting combinatorial complexity contributes to biological ...
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Alternative splicing is a key process in post-transcriptional regulation, by which different mature RNA can be obtained from the same premessenger RNA. The resulting combinatorial complexity contributes to biological diversity, especially in the case of the human immunodeficiency virus HIV-1. Using a constraint programming approach, we develop a model of the alternative splicing regulation in HIV-1. Our model integrates different scales (single site vs. multiple sites), and thus allows us to exploit several types of experimental data available to us. (C) 2004 Elsevier B.V. All rights reserved.
With the rapid growth of Online Social Networks (OSNs) and the information involved in them, research studies concerning OSNs, as well as the foundation of businesses, have become popular. Privacy on OSNs is typically...
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ISBN:
(纸本)9783319735214;9783319735207
With the rapid growth of Online Social Networks (OSNs) and the information involved in them, research studies concerning OSNs, as well as the foundation of businesses, have become popular. Privacy on OSNs is typically protected by anonymisation methods. Current methods are not sufficient to ensure privacy and they impose restrictions on the network making it not suitable for research studies. This paper introduces an approach to find an optimal anonymous graph under user-defined metrics using constraint programming, a technique that provides well-tested and optimised engine for combinatorial problems. The approach finds a good trade-off between protection of sensitive data and quality of the information represented by the network.
The problem studied in this paper is to schedule elective surgeries (in contrast to urgent surgeries) to multiple operating rooms (ORs) in ambulatory surgical settings. We focus on three aspects of the daily schedulin...
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The problem studied in this paper is to schedule elective surgeries (in contrast to urgent surgeries) to multiple operating rooms (ORs) in ambulatory surgical settings. We focus on three aspects of the daily scheduling decisions, including the number of ORs to open, the allocation of surgery-to-OR, and the sequence of surgeries in each OR. All the surgeries to be scheduled are known in advance, which is a common assumption for elective surgery scheduling problems. The surgeries belong to different types, and each OR can only allow certain types of surgeries to be performed. Before a surgery starts, some setup work needs to be done, such as sterilization and preparing required equipment. The setup times are assumed sequence-dependent, and both setup times and surgery durations are deterministic. The fixed costs of running the ORs are high;while sometimes overtime costs, which are even higher than the fixed costs, may occur when the surgeries cannot be done within the normal operating period of the ORs. We build a Mixed Integer Nonlinear programming (MINLP) model and a constraint programming (CP) model to solve this problem. The performance of these two models is tested on numerical examples, and the results show that the CP model is more efficient than the MINLP model in terms of the computational time and solution quality. We also examine the sensitivity of the solutions to the variation of surgery durations, and the analysis shows that the total costs do not change much when the variations of surgery durations are small. (C) 2014 Elsevier Ltd. All rights reserved.
The Traveling Tournament Problem with Predefined Venues (TTPPV) is a practical problem arising from sports scheduling. We describe two different modeling approaches for this problem, each of which is suitable for diff...
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ISBN:
(数字)9783030059187
ISBN:
(纸本)9783030059187;9783030059170
The Traveling Tournament Problem with Predefined Venues (TTPPV) is a practical problem arising from sports scheduling. We describe two different modeling approaches for this problem, each of which is suitable for different sizes of instance. The experimental results show that our modeling approaches lead to improved performance compared to previous techniques in terms of the number of feasible solutions and the optimal value. Furthermore, we present how to execute the models in parallel through data-level parallelism. The parallel versions do not only gain speedup but also attain significant improvement on optimal value since more subtrees are searched independently.
Resource constrained job scheduling is a hard combinatorial optimisation problem that originates in the mining industry. Off-the-shelf solvers cannot solve this problem satisfactorily in reasonable time-frames, while ...
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ISBN:
(纸本)9798400704949
Resource constrained job scheduling is a hard combinatorial optimisation problem that originates in the mining industry. Off-the-shelf solvers cannot solve this problem satisfactorily in reasonable time-frames, while other solution methods such as evolutionary computation methods and matheuristics cannot guarantee optimality and require low-level customisation and specialised heuristics to be effective. This paper addresses this gap by proposing a genetic programming algorithm to discover efficient search strategies of constraint programming for resource-constrained job scheduling. In the proposed algorithm, evolved programs represent variable selectors to be used in the search process of constraint programming, and their fitness is determined by the quality of solutions obtained by constraint programming for training instances. The novelties of this algorithm are (1) a new representation of variable selectors, (2) a new fitness evaluation scheme, and (3) a pre-selection mechanism. Tests with a large set of random and benchmark instances show that the evolved variable selectors can significantly improve the efficiency of constraining programming. Compared to highly customised metaheuristics and hybrid algorithms, evolved variable selectors can help constraint programming identify quality solutions faster and proving optimality is possible if sufficiently large run-times are allowed. The evolved variable selectors are especially helpful when solving instances with large numbers of machines.
In our paper, we analyze new exact approaches for the multi-mode resource-constrained project scheduling (MRCPSP) problem with the aim of makespan minimization. For the single-mode RCPSP (SRCPSP) recent exact algorith...
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In our paper, we analyze new exact approaches for the multi-mode resource-constrained project scheduling (MRCPSP) problem with the aim of makespan minimization. For the single-mode RCPSP (SRCPSP) recent exact algorithms combine a Branch and Bound algorithm with principles from constraint programming (CP) and Boolean Satisfiability Solving (SAT). We extend the above principles for the solution of MRCPSP instances. This generalization is on the one hand achieved on the modeling level. We propose three CP-based formulations of the MRCPSP for the G12 CP platform and the optimization framework SCIP which both provide solution techniques combining CP and SAT principles. For one of the latter we implemented a new global constraint for SCIP, which generalizes the domain propagation and explanation generation principles for renewable resources in the context of multi-mode jobs. Our constraint applies the above principles in a more general way than the existing global constraint in SCIP. We compare our approaches with the state-of-the-art exact algorithm from the literature on MRCPSP instances with 20 and 30 jobs. Our computational experiments show that we can outperform the latter approach on these instances. Furthermore, we are the first to close (find the optimal solution and prove its optimality for) 628 open instances with 50 and 100 jobs from the literature. In addition, we improve the best known lower bound of 2815 instances and the best known upper bound of 151 instances. (C) 2017 The Authors. Published by Elsevier Ltd.
constraint satisfaction modeling is both an efficient, and an elegant approach to model and solve many real world problems. In this paper, we present a constraint solver targeting module placement in static and partia...
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ISBN:
(纸本)9781467361804
constraint satisfaction modeling is both an efficient, and an elegant approach to model and solve many real world problems. In this paper, we present a constraint solver targeting module placement in static and partial run-time reconfigurable systems. We use the constraint solver to compute feasible placement positions. Our placement model incorporates communication, implementation variants and device configuration granularity. In addition, we model heterogeneous resources such as embedded memory, multipliers and logic. Furthermore, we take into account that logic resources consist of different types including logic only LUTs, arithmetic LUTs with carry chains, and LUTs with distributed memory. Our work targets state of the art field-programmable gate arrays (FPGAs) in both design-time and run-time applications. In order to evaluate our placement model and module placer implementation, we have implemented a repository containing 200 fully functional, placed and routed relocatable modules. The modules are used to implement complete systems. This validates the feasibility of both the model and the module placer. Furthermore, we present simulated results for run-time applications, and compare this to other state of the art research. In run-time applications, the results point to improved resource utilization. This is a result of using a finer tile grid and complex module shapes.
Parallel constraint programming (CP) solvers typically split the search space in disjoint subspaces, and run solvers independently on these. This may induce significant overhead when solving optimization problems. Par...
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ISBN:
(数字)9783319339542
ISBN:
(纸本)9783319339542;9783319339535
Parallel constraint programming (CP) solvers typically split the search space in disjoint subspaces, and run solvers independently on these. This may induce significant overhead when solving optimization problems. Parallel Boolean Satisfiability (SAT) solvers typically run a portfolio of solvers, all solving the same problem but sharing some limited learnt clause information. In this paper we consider parallelizing a lazy clause generation (LCG) constraint programming solver, which is a constraint programming solver with learning. Since it is both a kind of CP solver and a kind of SAT solver it is not clear which approach to parallelization is likely to be most effective. We give examples of very different kinds of optimization problems we wish to parallelize and show that a hybrid approach to parallelization can provide a robust and high performing parallel LCG solver.
We consider a steelmaking-continuous casting (SCC) scheduling problem in the steel industry, which is a variant of the hybrid flow shop scheduling problem subject to practical constraints. Recently, Hong et al. [Hong,...
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ISBN:
(纸本)9783031332708;9783031332715
We consider a steelmaking-continuous casting (SCC) scheduling problem in the steel industry, which is a variant of the hybrid flow shop scheduling problem subject to practical constraints. Recently, Hong et al. [Hong, J., Moon, K., Lee, K., Lee, K., Pinedo, M.L., International Journal of Production Research 60(2), 623-643 (2022)] developed an algorithm, called Iterated Greedy Matheuristic (IGM), in which a Mixed Integer programming (MIP) model was proposed and its sub-problems are iteratively solved to improve the solution. We propose a new constraint programming (CP) formulation for the SCC scheduling problem and develop an algorithm, called Iterated Greedy CP (IGC), which uses the framework of IGM but replaces the MIP model with our CP model. When we solve the CP subproblems iteratively, we also refine them by adding appropriate constraints, reducing the domains of the variables, and giving the variables hints derived from the current solution. From computational experiments in various settings, we show that IGC implemented with an open-source CP solver can be competitive with IGM running on a commercial MIP solver.
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