Search results for "Operations"
showing 10 items of 1692 documents
The Influence of Collective Behavior on Pacing in Endurance Competitions
2015
A number of theoretical models have been proposed in recent years to explain pacing strategies observed in individual competitive endurance events. These have typically related to the internal regulatory processes that inform the making of decisions relating to muscular work rate. Despite a substantial body of research which has investigated the influence of collective group dynamics on individual behaviors in various animal species, this issue has not been comprehensively studied in individual athletic events. This is somewhat surprising given that athletes often directly compete in close proximity to one another, and that collective behavior has also been observed in other human environme…
Tabu search for min-max edge crossing in graphs
2020
Abstract Graph drawing is a key issue in the field of data analysis, given the ever-growing amount of information available today that require the use of automatic tools to represent it. Graph Drawing Problems (GDP) are hard combinatorial problems whose applications have been widely relevant in fields such as social network analysis and project management. While classically in GDPs the main aesthetic concern is related to the minimization of the total sum of crossing in the graph (min-sum), in this paper we focus on a particular variant of the problem, the Min-Max GDP, consisting in the minimization of the maximum crossing among all egdes. Recently proposed in scientific literature, the Min…
The best choice problem with an unknown number of objects
1993
The secretary problem with a known prior distribution of the number of candidates is considered. Ifp(i)=p(N=i),i ∈ [α, β] ∩ ℕ, whereα=inf{i ∈ℕ:p(i) > 0} andβ=sup{i ∈ℕ:p(i)≳0}, is the prior distribution of the numberN of candidates it will be shown that, if the optimal stopping rule is of the simple form, then the optimal stopping indexj=minΓ satisfies asymptotically (asβ → ∞) the equationj=exp $${{\left[ {\left( {\sum\limits_{i = max(\alpha ,j)}^\beta {p(i) \log (i)/i} } \right)} \right]} \mathord{\left/ {\vphantom {{\left[ {\left( {\sum\limits_{i = max(\alpha ,j)}^\beta {p(i) \log (i)/i} } \right)} \right]} {\left. {\left( {\sum\limits_{i = max(\alpha ,j)}^\beta {p(i)/i} } \right) - 1} \ri…
Regulation and efficiency: the case of European railways
2001
Abstract During the long period of regulation of the railway system in Europe (1950s–1990s) the companies notably improved their levels of productivity. However, parallel to this, the state of their financial accounts also significantly worsened. In order to explain this fact we have estimated both cost and revenue frontier functions, calculating the losses associated with both cost and revenue inefficiencies as well as inefficiencies on the cost side. The results obtained show the existence of significant potential losses of revenue, which can be explained above all by the strong policy of regulation and intervention reigning in this period. A better commercial policy and a supply adapted …
Fixed points in weak non-Archimedean fuzzy metric spaces
2011
Mihet [Fuzzy $\psi$-contractive mappings in non-Archimedean fuzzy metric spaces, Fuzzy Sets and Systems, 159 (2008) 739-744] proved a theorem which assures the existence of a fixed point for fuzzy $\psi$-contractive mappings in the framework of complete non-Archimedean fuzzy metric spaces. Motivated by this, we introduce a notion of weak non-Archimedean fuzzy metric space and prove that the weak non-Archimedean fuzzy metric induces a Hausdorff topology. We utilize this new notion to obtain some common fixed point results for a pair of generalized contractive type mappings.
Evaluating the Reform of Healthcare System in Sicily: variations of efficiency and appropriateness between 2008 and 2010
2022

 
 Background. Sicilian government has developed a very ambitious Reform through the Regional Law n. 5 (14th April 2009). Hospitals were requested to ensure the quality of care through monitoring of appropriateness and quality of service. The aim of this study was to assess variations of efficiency and organizational appropriateness of healthcare delivery before and after this Reform and to show patterns associated to different types of healthcare delivery organizations.
 Methods. This study was based on repeated cross-sectional data for 118 (out of 129) short-term, acute-care, non teaching-and-research Sicilian hospitals, in 2008 and 2010. Congestion and slacks analysis was…
Monitoring multidimensional phenomena with a multicriteria composite performance interval approach
2021
[EN] In the last two decades, the construction of composite indicators to measure and compare multidimensional phenomena in a broad spectrum of domains has increased considerably. Different methodological approaches are used to summarise huge datasets of information in a single figure. This paper proposes a new approach that consists in computing a multicriteria composite performance interval based on different aggregation rules. The suggested approach provides an additional layer of information as the performance interval displays a lower bound from a non-compensability perspective, and an upper bound allowing for full-compensability. The outstanding features of this proposal are: 1) a dis…
Representação visual de custos no processo produtivo: estudo de caso em uma indústria calçadista de Portugal
2015
Ao longo das últimas décadas, os sistemas convencionais de produção passaram por mudanças diante da intensificação da competitividade entre empresas. As ocorrências dessas mudanças impulsionaram o desenvolvimento de ferramentas de auxílio à tomada de decisão para sistemas produtivos, no entanto, a maioria destes instrumentos não permite a visualização dos custos envolvidos ao longo das operações industriais. O presente estudo realiza a integração do Waste Identification Diagrams (WID), atual ferramenta para visualização e análise de processos produtivos, em conjunto com Time-Driven Activity-Based Costing (TDABC), ferramenta de gestão estratégica de custos, e procura criar um modelo que visu…
Managerial Growth Challenges in Small Software Firms: A Multiple-Case Study of Growth-Oriented Enterprises
2010
Notwithstanding the importance of small software firms, research focusing on understanding the growth challenges faced by their management is close to non-existent. By taking a life-cycle approach and focusing on managerial challenges, the aim of this paper is to analyze the growth process of small software firms. After forming a synthesis of possible growth challenges from relevant literature, the results are reflected upon case software firms using thematic interviews and questionnaires. According to the analysis of four software firms, managing human resources represents the greatest challenge for software services firms. Additionally, other challenges stem from competition and sales-rel…
Identifying individuality and variability in team tactics by means of statistical shape analysis and multilayer perceptrons.
2012
Abstract Offensive and defensive systems of play represent important aspects of team sports. They include the players’ positions at certain situations during a match, i.e., when players have to be on specific positions on the court. Patterns of play emerge based on the formations of the players on the court. Recognition of these patterns is important to react adequately and to adjust own strategies to the opponent. Furthermore, the ability to apply variable patterns of play seems to be promising since they make it harder for the opponent to adjust. The purpose of this study is to identify different team tactical patterns in volleyball and to analyze differences in variability. Overall 120 s…