Search results for "Operations Research"
showing 10 items of 1297 documents
Two-dimensional filters for structured text
1997
The paper introduces a method for defining filters for structured text. In the method, the text structure is originally defined by a grammar consisting of a set of productions. To describe the information interests, a two-dimensional template is first created interactively from the grammar to show the structure of a set of textual elements, at a chosen level of detail. The template depicts the hierarchical structure of the elements and indicates also optionality, alternatives, and iteration in the structure. Then, the template is filled by constraints and annotations. The constraints allow giving conditions to the content of parts, to the position of parts in an ordered set of parts, and to…
Biproportional Method for Analysing Interindustry Dynamics: the case of France
1990
Two elements are being presented in this paper: (1) A new and original method for analysing matrix dynamics, called the synthetical biproportional projector method (SBP), which can be used to project input–output tables and compare one with another. (2) Some results for France for the important period 1970–85. The paper starts with the observation that no systematic study of the change in the French productive structure as displayed In the input–output tables (tableaux entries-sorties in France) has ever been made. This is unfortunate, since a complete series of data is now available concerning a key period of the French economic evolution including the petroleum crisis, European integratio…
The technological transplant
1990
Abstract This paper deals with technology transfer and conditions for successful diffusion of renewable energy technologies in developing countries. Issues such as perception of needs and resources are fully discussed, whether on mega-scale or micro-scale; that is to say, whether for a specific project or a whole country. A distinction is made between technology and the technological device, the latter being a component which is injected into a social system creating new links into the pre-existing structure; therefore, even if perfect in itself, it may not fit into the system in which it has to operate. The need for a complete analysis of the effects of the injection (or transplant) of the…
A Unified Approach to Portfolio Optimization with Linear Transaction Costs
2004
In this paper we study the continuous time optimal portfolio selection problem for an investor with a finite horizon who maximizes expected utility of terminal wealth and faces transaction costs in the capital market. It is well known that, depending on a particular structure of transaction costs, such a problem is formulated and solved within either stochastic singular control or stochastic impulse control framework. In this paper we propose a unified framework, which generalizes the contemporary approaches and is capable to deal with any problem where transaction costs are a linear/piecewise-linear function of the volume of trade. We also discuss some methods for solving numerically the p…
Methods for defining user groups and user-adjusted information structures
1999
A common problem in the design of information systems is how to structure the information in a way that is most useful to different groups of users. This paper describes some statistical methods for revealing the structure inherent in empirical data elicited from users. It is illustrated by the application of these methods to the design of some web pages giving information about the Universitat de Valencia. Three potential user groups were identified, administrative staff, teaching staff and students. The first analysis demonstrated that users within these three groups assign relatively homogeneous structures, but that the structures assigned by the three groups are not the same, and also, …
The relationship between interdisciplinarity and distinct modes of university-industry interaction
2019
Abstract Interdisciplinary research (IDR) has raised increasing expectations among scholars and policymakers about its potential to produce ground-breaking scientific contributions and satisfy societal demands. While existing research highlights that novel connections across fields is beneficial for scientific contributions with high academic impact, comparatively less is known about whether IDR is positively associated to scientists’ engagement with non-academic actors. To investigate this, we examine whether there is a systematic relationship between scientists’ IDR-orientation and their interactions with industry. We conceptually distinguish four stylized modes of interaction (firm creat…
Closed-loop supply chains: What reverse logistics factors influence performance?
2016
This paper analyses the inventory and order flow dynamics in closed-loop supply chains (CLSCs). In this kind of supply chains the reverse flow of materials entering the system for recycling purposes complicates the way in which inventories should be managed and replenishment policies should be designed. Specifically, we analyse the relationships between some reverse logistics’ factors (remanufacturing lead-time, return rate of recycled products, reverse order policy, and number of supply chain tiers) on the order and inventory variance amplification. We firstly perform a systematic literature review of the related studies. Secondly, by adopting a difference equation math approach and design…
A Decisional Multi-Agent Framework for Automatic Supply Chain Arrangement
2013
In this work, a multi-agent system (MAS) for supply chain dynamic configuration is proposed. The brain of each agent is composed of a Bayesian Decision Network (BDN); this choice allows the agent for taking the best decisions estimating benefits and potential risks of different strategies, analyzing and managing uncertain information about the collaborating companies. Each agent collects information about customer's orders and current market prices, and analyzes previous experiences of collaborations with trading partners. The agent therefore performs a probabilistic inferential reasoning to filter information modeled in its knowledge base in order to achieve the best performance in the sup…
Impact of reverse logistics on supply chain performance
2013
Purpose – The purpose of this paper is to analyse the impact of reverse logistics on order and inventory variance amplification in a single-echelon supply chain (SC) and to propose a new order policy for dampening such amplification. Design/methodology/approach – A general review of the literature on sustainable operations and on the impact of reverse logistics on SC performance provides the foundation for the study. The authors use difference equation math approach for modelling and analysing a closed SC. A proper design of experiment and data collected from the European Union statistics validate the obtained numerical results. Findings – The variability of reverse flow in a closed loop S…
A Behavioral Approach for Logistics System Analysis and Design: A Reverse Logistics Case
2002
Traditional logistic system analysis quite often assumes a single decisionmaker (the planner) operating in a state of complete information and full decision power. He pursues the objective of designing an efficient logistic network by solving a sequence of operational problems mainly in the form of optimization models. More realistically, one should consider that the decision power is actually distributed within the logistics system among different actors (agents or holons) having different (conflictual or cooperative) goals, following different behavioural rules and generating interdipendencies. The shift from a SAS (single-agent system) approach to a MAS (multi-agent system) one induces s…