Search results for "Operations Research"
showing 10 items of 1297 documents
Towards Automatic Testing of Reference Point Based Interactive Methods
2016
In order to understand strengths and weaknesses of optimization algorithms, it is important to have access to different types of test problems, well defined performance indicators and analysis tools. Such tools are widely available for testing evolutionary multiobjective optimization algorithms. To our knowledge, there do not exist tools for analyzing the performance of interactive multiobjective optimization methods based on the reference point approach to communicating preference information. The main barrier to such tools is the involvement of human decision makers into interactive solution processes, which makes the performance of interactive methods dependent on the performance of huma…
Theory and regulation of liquidity risk management in banking
2016
Liquidity risk is now more important than it used to be in the past. The financial crisis has emphasised the importance of liquidity risk to the functioning of banking and financial system. The paper presents a theoretical and regulatory investigation of two types of liquidity risk: funding liquidity risk and market liquidity risk. The paper analyses the different approaches to measure the impact of funding and market liquidity risk in the economics and management of banks. The paper provides also an analysis of the organisational implications of the asset and liability management perspective of liquidity risk. Liquidity risk does not need to be covered by equity but by an adequate volume o…
Connections Between Single-Level and Bilevel Multiobjective Optimization
2011
The relationship between bilevel optimization and multiobjective optimization has been studied by several authors and there have been repeated attempts to establish a link between the two. We unify the results from the literature and generalize them for bilevel multiobjective optimization. We formulate sufficient conditions for an arbitrary binary relation to guarantee equality between the efficient set produced by the relation and the set of optimal solutions to a bilevel problem. In addition, we present specially structured bilevel multiobjective optimization problems motivated by real-life applications and an accompanying binary relation permitting their reduction to single-level multiob…
Gir boplikt lavere boligpriser?
2020
Siden 1974 har norske kommuner hatt adgang til å innføre boplikt for eiendommer som er eller har vært i bruk som helårsbolig. Ordningen har helt siden den ble innført, vært svært omstridt. Vi undersøker hvordan boplikt påvirker boligprisene. Geografisk avgrenser vi oss til kystkommuner på Sørlandet, der mange som har sin faste bopel andre steder i landet, etterspør fritidsbolig. Uten boplikt kan helårsboliger bli kjøpt opp for å bli brukt som fritidsboliger. Den empiriske analysen, basert på data fra fire sørlandskommuner, hvorav den største kommunen, Arendal, opphevet boplikten i 2014, viser at prisene i kystsonen økte da boplikten ble opphevet.
A branch-and-cut algorithm for the Team Orienteering Problem
2017
The Team Orienteering Problem aims at maximizing the total amount of profit collected by a fleet of vehicles while not exceeding a predefined travel time limit on each vehicle. In the last years, several exact methods based on different mathematical formulations were proposed. In this paper, we present a new two-index formulation with a polynomial number of variables and constraints. This compact formulation, reinforced by connectivity constraints, was solved by means of a branch-and-cut algorithm. The total number of instances solved to optimality is 327 of 387 benchmark instances, 26 more than any previous method. Moreover, 24 not previously solved instances were closed to optimality.
Social media overload, exhaustion, and use discontinuance : Examining the effects of information overload, system feature overload, and social overlo…
2020
While users’ discontinuance of use has posed a challenge for social media in recent years, there is a paucity of knowledge on the relationships between different dimensions of overload and how overload adversely affects users’ social media discontinuance behaviors. To address this knowledge gap, this study employed the stressor–strain–outcome (SSO) framework to explain social media discontinuance behaviors from an overload perspective. It also conceptualized social media overload as a multidimensional construct consisting of system feature overload, information overload, and social overload. The proposed research model was empirically validated via 412 valid questionnaire responses collecte…
The M/G/1/1 queue with repeated attempts and different types of feedback effects
1985
Queueing systems with repeated attempts have wide practical use in designing switching networks and computer systems. The model presented in this paper not only takes into account repetitions by congestion but also considers the feedback effects from all types of failures in establishing a connection. A semi-regenerative analysis is applied in order to determine the characteristics of the underlying queueing process. Bedienungssysteme mit wiederholten Versuchen sind von groβem praktischen Nutzen bei der Bemessung von Vermittlungseinrichtungen und Computersystemen. Das Modell, das in dieser Arbeit vorgestellt wird, berucksichtigt nicht nur Wiederholungen nach vorangegangener Blockierung, son…
Hybrid descriptive-inferential method for key feature selection in prostate cancer radiomics
2021
In healthcare industry 4.0, a big role is played by radiomics. Radiomics concerns the extraction and analysis of quantitative information not visible to the naked eye, even by expert operators, from biomedical images. Radiomics involves the management of digital images as data matrices, with the aim of extracting a number of morphological and predictive variables, named features, using automatic or semi-automatic methods. Multidisciplinary methods as machine learning and deep learning are fully involved in this field. However, the large number of features requires efficient and effective core methods for their selection, in order to avoid bias or misinterpretations problems. In this work, t…
Financial crisis impact on sustainability reporting
2013
Purpose – The purpose of this paper is to shed some light on the effect of the current financial crisis on corporate social responsibility (CSR) reporting and CSR assurance strategies that companies disclose online to stakeholders, by dividing the time horizon into two periods, before 2008 and from 2008. Design/methodology/approach – The sample includes Spanish listed companies, differentiating CSR reporters from non CSR-reporters. Also distinguished in the CSR-reporters sample, are those companies that assure the CSR report from those that do not. The authors contrast whether there is a trend as regards CSR reporting and CSR assurance, depending on whether the crisis has already begun or …
Public versus private broadcasters’ management
2014
Purpose – The purpose of this paper is to prove the existence of significant differences between private and public corporate credibility antecedents and effects. Design/methodology/approach – Totally, 816 Spanish viewers’ valuations were obtained (408 for the public television network and 408 for four private first generation broadcasters). Results show that some corporate reputation antecedents (perceived quality) and effects (attitudes) are stronger when private broadcasters are considered. Findings – Result show that proposed credibility reputation antecedents and effects are significant and that some differences between private and public entities really do exist. Research limitations…