Search results for "Management Science"
showing 10 items of 1017 documents
Formulations and exact algorithms for the distance-constrained generalized directed rural postman problem
2017
[EN] The generalized directed rural postman problem is an arc routing problem with many interesting real-life applications, such as routing for meter reading. In this application, a vehicle with a receiver travels through a series of neighborhoods. If the vehicle gets closer than a certain distance to a meter, the receiver is able to record the gas, water, or electricity consumption. Therefore, the vehicle does not need to traverse every street, but only a few, to get close enough to each meter. We study an extension of this problem in which a fleet of vehicles is available. Given the characteristics of the mentioned application, the vehicles have no capacities but there is a maximum distan…
A heuristic algorithm for project scheduling with splitting allowed
1996
In this article, we analyze the precedence diagramming method, the only published algorithm for time-only project scheduling with activity splitting allowed. The criteria used in this method (forward and backward pass computations) for deciding when an activity has to be interrupted are shown to be invalid in some situations. We look into the causes of these failures and propose new formulae that always provide feasible solutions. The new algorithm has been tested on 240 randomly generated problems ranging up to 600 activities and 7,200 precedence relationships, resulting in an average deviation from optima of less than 1 percent.
Using Dynamic Stories to Communicate Security and Safety Issues
2008
System dynamics (SD) models contain valuable insights on complex organizational issues that develop over time. However, for non-experts such models can be complex and difficult to understand. We propose Dynamic Stories, a methodology that uses storytelling, to rephrase expert terminology in simpler to understand action terms, thus overcoming knowledge transfer problems. To show the feasibility of the approach, we present our methodological framework.
A qualitative model of the HIV vital cycle
1992
Qualitative modelling is a recent artificial intelligence approach to physical system modelling. This approach has been successfully applied in several fields. On the basis of an analysis and qualitative modelling of cell growth, we reckon that a qualitative model of the vital cycle of HIV can be proposed, including the phases in which HIV can be attacked. The actions of antiviral drugs can also be qualitatively modelled, provided their action mechanism is known, even only in a broad sense.
Hybrid Conflicts Actors’ Action Models Analysis
2021
Abstract The present article highlights the need to understand the physiognomy of hybrid conflicts, the action methodology of the actors in these conflicts, and aims to identify the correlation between the characteristics of the hybrid operational environment and the typology of participating actors in order to model future military actions. The ever-changing nature of the operational environment emphasizes the importance of understanding the military phenomenon in terms of the process of conflict management and resolution, in general, and of the hybrid conflicts in particular.
Contingent claim valuation in a market with different interest rates
1995
The problem of contingent claim valuation in a market with a higher interest rate for borrowing than for lending is discussed. We give results which cover especially the European call and put options. The method used is based on transforming the problem to suitable auxiliary markets with only one interest rate for borrowing and lending and is adapted from a paper of Cvitanic and Karatzas (1992) where the authors study constrained portfolio problems.
Value preserving portfolio strategies and the minimal martingale measure
1998
We consider some relations between the minimal martingale measure and the value preserving martingale measure in a continuous-time securities market. Under the assumption of continuous share prices we show that under a structure condition both these martingale measures exist and indeed coincide. This however does not mean that the corresponding concepts of value preserving portfolio strategies and (local) risk minimisation in the area of option hedging in incomplete markets are identical.
Adaptive memory programing for the robust capacitated international sourcing problem
2008
The International Sourcing Problem consists of selecting a subset from an available set of potential suppliers internationally located. The selected suppliers must meet the demand for items from a set of plants, which are also located worldwide. Since the costs are affected by macroeconomic conditions in the countries where the supplier and the plant are located, the formulation considers the uncertainty associated with changes in these conditions. We formulate the robust capacitated international sourcing problem by means of a scenario-optimization approach. When dealing with uncertainty, one of the most common approaches in the literature is to formulate the problem via a set of possible …
Three Issues in Multilevel Research
2019
AbstractIn this article, three important issues in organizational multilevel research are discussed and clarified, namely: (a) The interpretation of “cross-level direct effects” in theoretical and research multilevel models, (b) the specification of the emergence processes involved in higher-level constructs, and (c) the sample size recommendations for using multilevel statistical methods. By doing so, this article hopes to contribute to the improvement of organizational multilevel research.
Construction of quality of life change patterns: example in oncology in a phase III therapeutic trial (FFCD 0307)
2015
Objective Quality of life data in cancerology are often difficult to summarize due to missing data and difficulty to analyze the pattern of evolution in different groups of patients. The aim of this work was to apply a new methodology to construct Quality of Life (QoL) change patterns within patients included in a clinical trial comparing to regimen of treatment in locally advanced eosogastric cancer. Materials and methods In this trial, QoL was assessed every 2 months by self-reported EORTC QLQ-C30 questionnaire. Physical dimension scores were analyzed. After multiple imputation of missing data, 27 statistical measures aiming to describe the variation of QoL measures among follow-up were c…