Leonilde Varela

Dynamic MCDM with future knowledge for supplier selection

Dynamic multi-criteria decision making (DMCDM) is an emerging subject in the decision-making area and in the last decade the challenge to consider time as an important variable has become important. Some frameworks already exist in this area but when compared with other types of decision-making models, DMCDM needs more work to be applicable in real industrial problems. In this work we extend a dynamic spatial-temporal framework, designed to deal with historical data (feedback), to address the problem of considering future information/knowledge (feed-forward). The main objective is to enrich dynamic decision-making models with explicit knowledge (existing historical data) and tacit knowledge (e.g. expert predictions) in time-evolving problems, such as supplier selection. Considering supplier-predicted information for future situations (e.g. investments in capacity) and, simultaneously, learning from historical data can help a company to find less risky and consistent alternatives. The proposed model is successfully implemented in a real case study for supplier selection in one automotive industry to demonstrate the capability and applicability of the model.

Fuzzy Optimization using Simulated Annealing:An Example Set

In this paper we tested a set of examples, presented in the literature, with a general fuzzy optimization approach using Simulated Annealing (SA). For linear fuzzy problems, we selected a set of examples from well-known authors. For non-linear fuzzy optimization problems we selected two crisp problems and only two fuzzy examples because there are not many fuzzy non-linear examples in the literature. The comparison of the results, obtained with our approach and the ones shown in the literature, allow us to highlight the flexibility, generality and performance of this fuzzy approach to solve either linear or non-linear fuzzy optimization problems.

A Model for B2B Supplier Selection

A supply chain is a set of geographically dispersed facilities that store and transform products, and that are connected by a transportation network. The main task of supply chain management is to design the supply chain so that a given set of objectives is achieved, for example by deciding the location and capacity of new production plants, or the location of warehouses. Since suppliers also play a key role in performance maximization, it is natural to integrate them in the supply chain as well [8]. For this reason, selection of potential suppliers has become a fundamental component of supply chain management; this is even more true in the globalized market of today. The problem of supplier selection can be easily understood as a multiple-criteria decision making (MCDM) problem: businesses express their preferences with respect to suppliers, which can then be ranked and selected. Doing so, however, does not take into account the temporal evolution of supplier performances, neither can it be easily applied when considering more than one customer. To overcome these problems, we introduce a model for supplier selection that extends the classic MCDM model by introducing feedback, and consider its application in the context of multiple customers by means of linear programming.

An XML Knowledge Base System for Scheduling Problems

Production Scheduling is an important function strongly contributing to the competitiveness of industrial and service companies. In this communication we make a contribution for XML based specification of scheduling concepts in order to allow for a standard representation of scheduling problems and related tasks. This information modeling is used in the development of a web based decision support system for the resolution of scheduling problems. An XML-based Knowledge Base System may be useful not only to facilitate the specification of scheduling problems but also in the search for the most suitable available algorithms and methods, which can then be used for finding good solutions to the problems. The existing algorithms, as well as their corresponding implementations, may either be local or remotely available, through the Internet.

A Cloud-Based Architecture with embedded Pragmatics Renderer for Ubiquitous and Cloud Manufacturing

The paper presents a Cloud-based architecture for Ubiquitous and Cloud Manufacturing as a multilayer communicational architecture designated as the Communicational Architecture. It is characterised as (a) rich client interfaces (Rich Internet Application) with sufficient interaction to allow user agility and competence, (b) multimodal, for multiple client device classes support and (c) communicational to allow pragmatics, where human-to-human real interaction is completely supported. The main innovative part of this architecture is sustained by a semiotic framework organised on three main logical levels: (a) device level, which allows the user ‘to use’ pragmatics with the system, (b) application level which results for a set of tools which allows users pragmatics-based interaction and (c) application server level that implements the Pragmatics renderer, a pragmatics supporting engine that supports all pragmatics services. The Pragmatics renderer works as a communication enabler, and consists of a set of integrated collaboration technology that makes the bridge between the user/devices and the ‘system’. A federated or community cloud is developed using a particular cloud RESTful Application Programming Interface that supports (cloud) services registration, composition and governance (pragmatics services behaves as SaaS in the cloud).

Developing a Web Scheduling System Based on XML Modeling

In manufacturing enterprises, it is important nowadays, as a competitive strategy, to explore and use software applications, now becoming available through the Internet and Intranets, for solving scheduling problems. This work gives a contribution for a better resolution process of scheduling problems, by means of web-based computation. An XML-based specification framework for scheduling is proposed. This specification provides a general model of scheduling problems and related tasks, and consequently a method of describing each particular problem and algorithm, by user information introduction. The main objective of this kind of specification is to make possible flexible communication among different scheduling applications, in a web-based scheduling decision support system.

A Knowledge Based System for Supporting Sustainable Industrial Management in a Clothes Manufacturing Company Based on a Data Fusion Model

In this paper we propose a knowledge based system (KBS), based on smart objects and a data fusion model to support industrial management decision making applied to a clothes manufacturing enterprise. The management processes cover factory-production levels to higher decision-making levels. Therefore, the proposed KBS contributes to solving different kind of decision problems, including factory supervision, production planning and control, productivity management, real-time monitoring, and data acquisition and processing. The web access via different middleware devices and tools at different process levels, along with the use of integrated algorithms, decision methods, and smart objects, promote an optimized use of knowledge and resources. In this paper the proposed KBS is introduced and an example of its use is illustrated with an example of a clothes manufacturing resources selection, using the embedded dynamic multi-criteria fusion model.

Scheduling single-machine problem based on just-in-time principles

In this paper are applied heuristics that try to find good solutions for a static single machine scheduling problem. In the considered problem different processing times and due dates are used and no preemption is allowed. The heuristics applied consider several performance measures, which intend to be customer and enterprise oriented. Customer oriented performance measures are mainly related to the accomplishment of due dates while enterprise-oriented ones typically consider other time-oriented measures, like the makespan. The heuristics used in this work are focused on Just-in-Time principles and on different costumer and enterprise performance measures, although preference is given to customer-oriented measures, namely the total number of tardy jobs and the maximum tardiness.

An Architecture for a Web Service Based Product Configuration Information System

Competition in the today’s global economy is intensifying the use of the new paradigm of mass customization. Such a paradigm is characterized by the need to deal with a very large variety of products determined by a substantial increase in customer specific product requirements. Implementing this paradigm requires agility and effectiveness in the customer-producer interaction and also in the order-production-delivery cycle. Web-based product configurators can provide an opportunity for improved interaction between producer and customer, and for a more formal, agile and effective process of both product and customer orders specification. In this paper, we propose architecture and describe the functionalities of a web based system for interactive product and customer order configuration. The proposed system can be also of value for supporting product data management and the production and delivery functions.

Improving Productivity and Standard Time Updating in an Industrial Company – A Case Study

Today’s marketplace imposes ever-tightening product pricing and quality requirements, shorter delivery times, and increasingly customized products. With increasing competition in today’s global market, companies are increasingly pressured to improve the performance of their production systems in order to be more competitive and improve market share. In order to try to satisfy these requirements several companies seek for the application of methodologies that may enable them to respond to these challenges, such as the ones based on the Lean Manufacturing philosophy. In this work standard times of four extruders are determined and updated in the context of setup time’s analysis and minimization in a company, in Portugal. First, a diagnosis is made to the tire floor extrusion process in order to evaluate all of its inefficiencies with the greatest impact on the production process, after the standard time of each extruder is analysed and updated through an extended approach which does also consider setup times reduction, along with the production times, for reaching a higher process optimization rate and productivity in the underlying production system.