Search results for "versification"
showing 10 items of 185 documents
Intelligent Multi-Start Methods
2018
Heuristic search procedures aimed at finding globally optimal solutions to hard combinatorial optimization problems usually require some type of diversification to overcome local optimality. One way to achieve diversification is to re-start the procedure from a new solution once a region has been explored, which constitutes a multi-start procedure. In this chapter we describe the best known multi-start methods for solving optimization problems. We also describe their connections with other metaheuristic methodologies. We propose classifying these methods in terms of their use of randomization, memory and degree of rebuild. We also present a computational comparison of these methods on solvi…
Most Diverse Near-Shortest Paths
2021
Computing the shortest path in a road network is a fundamental problem that has attracted lots of attention. However, in many real-world scenarios, determining solely the shortest path is not enough as users want to have additional, alternative ways of reaching their destination. In this paper, we investigate a novel variant of alternative routing, termed the k-Most Diverse Near-Shortest Paths (kMDNSP). In contrast to previous work, kMDNSP aims at maximizing the diversity of the recommended paths, while bounding their length based on a user-defined constraint. Our theoretical analysis proves the NP-hardness of the problem at hand. To compute an exact solution to kMDNSP, we present an algori…
Multi-Start Methods
2006
Heuristic search procedures that aspire to find global optimal solutions to hard combinatorial optimization problems usually require some type of diversification to overcome local optimality. One way to achieve diversification is to re-start the procedure from a new solution once a region has been explored. In this chapter we describe the best known multi-start methods for solving optimization problems. We propose classifying these methods in terms of their use of randomization, memory and degree of rebuild. We also present a computational comparison of these methods on solving the linear ordering problem in terms of solution quality and diversification power.
Advanced Multi-start Methods
2010
Heuristic search procedures that aspire to find globally optimal solutions to hard combinatorial optimization problems usually require some type of diversification to overcome local optimality. One way to achieve diversification is to re-start the procedure from a new solution once a region has been explored. In this chapter we describe the best known multi-start methods for solving optimization problems. We propose classifying these methods in terms of their use of randomization, memory, and degree of rebuild. We also present a computational comparison of these methods on solving the maximum diversity problem in terms of solution quality and diversification power.
2018
In recent decades, the massification and diversification of higher education have generated new challenges for the guidance of university students. The present study focuses on students’ experience...
Feeding and management techniques to favour summer sheep milk and cheese production in the Mediterranean environment
2015
Sheep milk production in summer can lead to a diversification of milk products and to a more regular product distribution in the market throughout the year. However, in Mediterranean countries small ruminant production cycles are subjected to seasonal variations in forage resources. During summer, a key period for out of season production systems, nutrition plays a fundamental role in regulating the quantity and quality of milk production. In this review, feeding strategies and techniques that could be applied for out of season production in dairy ewes under different Mediterranean conditions are described for intensive, pasture-based and mixed systems. The most common feeding strategies us…
Where is the line? Phylogeography and secondary contact of western Palearctic coal tits (Periparus ater: Aves, Passeriformes, Paridae)
2013
In this study, a phylogeographic scenario of the coal tit (Periparus ater) was reconstructed based on a fragment of the mitochondrial control region, and within- and between-population genetic diversity was analysed with a focus on the western Palearctic breeding range. We inferred a first pan-European delimitation of a postulated secondary contact zone among coal tits from the north-eastern Palearctic ater subspecies group and those from the south-western Palearctic abietum group. Generally, between-population differentiation was greatest in the Mediterranean range, which was explained by a greater separation in multiple Pleistocene refuge areas compared to the lower differentiation across…
Antibiotics as selectors and accelerators of diversity in the mechanisms of resistance: from the resistome to genetic plasticity in the β-lactamases …
2013
Antibiotics and antibiotic resistance determinants, natural molecules closely related to bacterial physiology and consistent with an ancient origin, are not only present in antibiotic-producing bacteria. Throughput sequencing technologies have revealed an unexpected reservoir of antibiotic resistance in the environment. These data suggest that co-evolution between antibiotic and antibiotic resistance genes has occurred since the beginning of time. This evolutionary race has probably been slow because of highly regulated processes and low antibiotic concentrations. Therefore to understand this global problem, a new variable must be introduced, that the antibiotic resistance is a natural even…
Economies of diversification in microfinance: Evidence from quantile estimation on panel data
2020
Abstract Prior studies of the diversification-driven cost savings from the joint provision of credit and deposits in microfinance usually ignore the multi-way heterogeneity across MFIs which vary substantially in size, business model, target clientele and operate in diverse environments. Using a quantile panel data model with correlated effects capable of accommodating multiple heterogeneity, we show that the typical measurement of economies of diversification at the mean provides an incomplete and distorted picture of their magnitude and prevalence in the industry. While we find statistically significant estimates, they are modest for most small-size MFIs but are quite substantial for larg…
Should Microfinance Institutions diversify or focus? A global analysis
2018
Abstract This paper investigates the effects of revenue diversification on the financial performance of microfinance institutions (MFIs). The long-standing question about whether financial institutions should diversify or focus is a topic of ongoing debate. Using a global sample of MFIs, we investigate which view is appropriate for microfinance institutions. The results show that, diversification across revenue streams improves sustainability and profitability of MFIs. This suggests that revenue diversification is an important strategy for the sustainability of microfinance.