48,492 research outputs found
Ant colony system-based applications to electrical distribution system optimization
Chapter 16, February 201
High-Level Object Oriented Genetic Programming in Logistic Warehouse Optimization
DisertaÄnĂ prĂĄce je zamÄĆena na optimalizaci prĆŻbÄhu pracovnĂch operacĂ v logistickĂœch skladech a distribuÄnĂch centrech. HlavnĂm cĂlem je optimalizovat procesy plĂĄnovĂĄnĂ, rozvrhovĂĄnĂ a odbavovĂĄnĂ. JelikoĆŸ jde o problĂ©m patĆĂcĂ do tĆĂdy sloĆŸitosti NP-teĆŸkĂœ, je vĂœpoÄetnÄ velmi nĂĄroÄnĂ© nalĂ©zt optimĂĄlnĂ ĆeĆĄenĂ. MotivacĂ pro ĆeĆĄenĂ tĂ©to prĂĄce je vyplnÄnĂ pomyslnĂ© mezery mezi metodami zkoumanĂœmi na vÄdeckĂ© a akademickĂ© pĆŻdÄ a metodami pouĆŸĂvanĂœmi v produkÄnĂch komerÄnĂch prostĆedĂch. JĂĄdro optimalizaÄnĂho algoritmu je zaloĆŸeno na zĂĄkladÄ genetickĂ©ho programovĂĄnĂ ĆĂzenĂ©ho bezkontextovou gramatikou. HlavnĂm pĆĂnosem tĂ©to prĂĄce je a) navrhnout novĂœ optimalizaÄnĂ algoritmus, kterĂœ respektuje nĂĄsledujĂcĂ optimalizaÄnĂ podmĂnky: celkovĂœ Äas zpracovĂĄnĂ, vyuĆŸitĂ zdrojĆŻ, a zahlcenĂ skladovĂœch uliÄek, kterĂ© mĆŻĆŸe nastat bÄhem zpracovĂĄnĂ ĂșkolĆŻ, b) analyzovat historickĂĄ data z provozu skladu a vyvinout sadu testovacĂch pĆĂkladĆŻ, kterĂ© mohou slouĆŸit jako referenÄnĂ vĂœsledky pro dalĆĄĂ vĂœzkum, a dĂĄle c) pokusit se pĆedÄit stanovenĂ© referenÄnĂ vĂœsledky dosaĆŸenĂ© kvalifikovanĂœm a trĂ©novanĂœm operaÄnĂm manaĆŸerem jednoho z nejvÄtĆĄĂch skladĆŻ ve stĆednĂ EvropÄ.This work is focused on the work-flow optimization in logistic warehouses and distribution centers. The main aim is to optimize process planning, scheduling, and dispatching. The problem is quite accented in recent years. The problem is of NP hard class of problems and where is very computationally demanding to find an optimal solution. The main motivation for solving this problem is to fill the gap between the new optimization methods developed by researchers in academic world and the methods used in business world. The core of the optimization algorithm is built on the genetic programming driven by the context-free grammar. The main contribution of the thesis is a) to propose a new optimization algorithm which respects the makespan, the utilization, and the congestions of aisles which may occur, b) to analyze historical operational data from warehouse and to develop the set of benchmarks which could serve as the reference baseline results for further research, and c) to try outperform the baseline results set by the skilled and trained operational manager of the one of the biggest warehouses in the middle Europe.
Search based software engineering: Trends, techniques and applications
© ACM, 2012. This is the author's version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version is available from the link below.In the past five years there has been a dramatic increase in work on Search-Based Software Engineering (SBSE), an approach to Software Engineering (SE) in which Search-Based Optimization (SBO) algorithms are used to address problems in SE. SBSE has been applied to problems throughout the SE lifecycle, from requirements and project planning to maintenance and reengineering. The approach is attractive because it offers a suite of adaptive automated and semiautomated solutions in situations typified by large complex problem spaces with multiple competing and conflicting objectives.
This article provides a review and classification of literature on SBSE. The work identifies research trends and relationships between the techniques applied and the applications to which they have been applied and highlights gaps in the literature and avenues for further research.EPSRC and E
Distributed Optimization: Convergence Conditions from a Dynamical System Perspective
This paper explores the fundamental properties of distributed minimization of
a sum of functions with each function only known to one node, and a
pre-specified level of node knowledge and computational capacity. We define the
optimization information each node receives from its objective function, the
neighboring information each node receives from its neighbors, and the
computational capacity each node can take advantage of in controlling its
state. It is proven that there exist a neighboring information way and a
control law that guarantee global optimal consensus if and only if the solution
sets of the local objective functions admit a nonempty intersection set for
fixed strongly connected graphs. Then we show that for any tolerated error, we
can find a control law that guarantees global optimal consensus within this
error for fixed, bidirectional, and connected graphs under mild conditions. For
time-varying graphs, we show that optimal consensus can always be achieved as
long as the graph is uniformly jointly strongly connected and the nonempty
intersection condition holds. The results illustrate that nonempty intersection
for the local optimal solution sets is a critical condition for successful
distributed optimization for a large class of algorithms
Project network models with discounted cash flows. A guided tour through recent developments.
The vast majority of the project scheduling methodologies presented in the literature have been developed with the objective of minimizing the project duration subject to precedence and other constraints. In doing so, the financial aspects of project management are largely ignored. Recent efforts have taken into account discounted cash flow and have focused on the maximalization of the net present value (npv) of the project as the more appropriate objective. In this paper we offer a guided tour through the important recent developments in the expanding field of research on deterministic and stochastic project network models with discounted cash flows. Subsequent to a close examination of the rationale behind the npv objective, we offer a taxonomy of the problems studied in the literature and critically review the major contributions. Proper attention is given to npv maximization models for the unconstrained scheduling problem with known cash flows, optimal and suboptimal scheduling procedures with various types of resource constraints, and the problem of determining both the timing and amount of payments.Scheduling; Models; Model; Discounted cash flow; Cash flow; Project scheduling; Project management; Management; Net present value; Value; Problems; Maximization; Optimal;
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