314 research outputs found
A multi-paradigm tool for large neighborhood search
No full textStudies in Computational Intelligence
Volume 434, 2013, Pages 389-414
A multi-paradigm tool for large neighborhood search (Article)
Cipriano, R.a , Di Gaspero, L.b , Dovier, A.a
a Dipartimento di Matematica e Informatica, Università Degli Studi di Udine, via delle Scienze 208, I-33100 Udine, Italy
b Dipartimento di Ingegneria Elettrica, Gestionale EMeccanica, Università Degli Studi di Udine, via delle Scienze 208, I-33100 Udine, Italy
View references (21)
Abstract
We present a general tool for encoding and solving optimization problems. Problems can be modeled using several paradigms and/or languages such as: Prolog, MiniZinc, and GECODE. Other paradigms can be included. Solution search is performed by a hybrid solver that exploits the potentiality of the Constraint Programming environment GECODE and of the Local Search framework EasyLocal++ for Large Neighborhood Search. The user can modify a set of parameters for guiding the hybrid search. In order to test the tool, we show the development phase of hybrid solvers on some benchmark problems. Moreover, we compare these solvers with other approaches, namely a pure Local Search, a pure constraint programming search, and with a state-of-the-art solver for constraint-based Local Search
On the hybridization of constraint programming and local search techniques. Models and software tools
No full textA hybrid approach mixing local search and constraint programming applied to the protein structure prediction problem
No full textA Hybrid Solver for Large Neighborhood Search: Mixing Gecode and EasyLocal++
No full textWe present a hybrid solver (called GELATO) that exploits the potentiality of a Constraint Programming (CP) environment (Gecode) and of a Local Search (LS) framework (EasyLocal++). GELATO allows the user to easily develop and use hybrid meta-heuristic combining CP and LS phases (in particular Large Neighborhood Search). We tested some hybrid algorithms on different instances of the Asymmetric Traveling Salesman Problem: even if only naive LS strategies have been used, our meta-heuristics improve the standard CP and LS methods, in terms of both quality of the solution reached and execution time. GELATO will be integrated into a more general tool to solve Constraint Satisfaction/ Optimization Problems. Moreover, it can be seen as a new library for approximate and efficient searching in Gecode
Hybrid Approaches for Rostering: a Case Study in the Integration of Constraint Programming and Local Search
No full textDifferent approaches in the hybridization of constraint programming and local search techniques have been recently proposed in the literature. In this paper we investigate two of them, namely the employment of local search to improve a solution found by constraint programming and the exploitation of a constraint model to perform the exploration of the local neighborhood. We apply the two approaches to a real-world personnel rostering problem arising at the department of neurology of the Udine University hospital and we report on computational studies on both real-world and randomly generated structured instances. The results highlight the benefits of the hybridization approach w.r.t. their component algorithms
A Novel De Novo STAG1 Variant in Monozygotic Twins with Neurodevelopmental Disorder: New Insights in Clinical Heterogeneity
No full textBackground: The STAG1 gene encodes a component of the cohesin complex, involved in chromosome segregation and DNA repair. Variants in genes of the cohesin complex determine clinical conditions characterized by facial dysmorphisms, upper limb anomalies, intellectual disability, and other neurological deficits. However, to date, the STAG1-related clinical phenotype has been poorly investigated (around 20 cases reported). Methods and Results: We report, for the first time, two twins affected by a syndromic neurodevelopmental disorder associated with a de novo variant in the STAG1 gene. Although both the twins showed a neurodevelopmental delay, one of them showed a more severe phenotype with greater behavioral problems, speech defects and limb apraxia. CGH array showed a 15q13.3 microduplication, inherited from an unaffected mother. Conclusions: We found different degrees of behavioral, speech and cognitive impairment in two twins affected by a neurodevelopmental disorder associated with a STAG1 variant. These findings highlight the variability of the STAG1-associated phenotype or a probable role of associated variants (like the discovered 15q13.3 microduplication) in modulating the clinical features
Responsabilità e risarcimento per il danno cagionato dall'incapace (artt. 2046-2047 del codice civile).
No full textAbstract: The work treats of civil liability, damages and imputability. First the author explores the notion of imputability, liability and guilt and the “actiones liberae in causa”. Then it analyzes the autonomy between criminal and civil liability. Afterwards, the focus is on natural and legal incapacity: the younger age group and the mentally ill. Then the work analyzes the contributory negligence of the incapacitated person and the compensation of non-pecuniary damage. Imputability and strict liability is also considered. Afterwards, the work analyzes compensation for damages occasioned by incapable and the liability of parties responsible for negligent supervision. At last, the work examines the evidence release under Italian Civil Code article 2047 and the compensation when strict liability can’t be stated
Il cane della necropoli di Porte di Ferro (VIII sec. A.C.) a San Cipriano Picentino (Salerno).
No full textMega-litter and remediation: the case of Mar Piccolo of Taranto (Ionian Sea)
No full textAccording to the United Nations Environment Programme/Mediterranean Action Plan (UNEP/MAP), marine litter is one of the main causes of marine pollution in the Mediterranean Sea and one of the most important threats for its biodiversity. In addition, it is a critical issue with significant implications from an ecological point of view, as well as for human health and safety. The present study provides a focus concerning the mega-litter in a semi-enclosed basin, the Mar Piccolo of Taranto (Southern Italy, Ionian Sea). In this basin, characterized by a suite of anthropic impacts, a specific protocol for the mega-litter removal has been developed according to the Special Commissioner for remediation of the Site of National Interest of Taranto. The application of such protocol proved to be effective in limiting the removals’ secondary effects on the biodiversity and on the environment as a whole, allowing a sustainable removal of marine mega-litter. A critical part of such protocol resulted in the translocation of species of conservation interest present on the debris, particularly considering the rich population of the pen shell Pinna nobilis thriving in the area. A total of 7107 specimens were translocated, showing low mortality percentage and high survival rates during 9 months of monitoring
Design for form postponement: do not overlook organization design
No full textPurpose - The purpose of this paper is to develop a theory of the organizational changes related to the production-planning process that facilitate application of form postponement (FP), an increasingly popular operations-design principle meant to alleviate the negative impact of product variety and customization on operational performance.
Design/methodology/approach - To achieve the theory-building objective, a multiple-case study involving four cases in the machinery industry was designed. In the inductive theory-building process, the authors borrowed from the information-processing theory to further corroborate the internal validity and generalizability of the findings.
Findings - The theory proposed by the author indicates that greater utilization of lateral relations in the production-planning process, higher production-planning frequency, greater degree of self-containment of the production-planning task, and simplification of the production planning-related environment favor application of FP.
Research limitations/implications - The level of analysis of the theory is the production-planning process of a product family within a company. Future research could extend inquiry of the organizational antecedents of FP at both higher and lower levels of analysis, such as the organization as a whole or the individuals participating in the production-planning process.
Practical implications - The theory supports managerial decision making by suggesting how to redesign the organization part involved in the production-planning process of a product family in order to apply FP. The difficulty and cost of this organizational redesign effort should be taken into account when companies consider FP implementation.
Originality/value - Past research has focused on changes to product design and to the manufacturing and supply chain process that enable FR This paper augments the understanding of FP enablers by developing the first model of organizational antecedents of FP. It also responds to calls for more research integrating insights from organization theory and operations/supply chain management
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