Catálogo de publicaciones - libros

Production planning and control is a highly complex process influenced by many factors. An important part of this broad task is demand forecasting, for which many methods already have been developed. But due to the occurring dynamics in the used data, the prediction may differ strongly from the optimum and thus errors leading to rising costs are inevitable. In this paper we will propose the entropy as a measurement for the quality of order forecasting respectively as relative estimation for the forecasting error. In general, entropy is a measurement for disorder and thus also for information content. Since lack of information leads to inaccuracy of forecasting, the entropy can be identified with the quality of order prediction. First results on the basis of time-series obtained from mathematical functions, discrete-event simulations of a production network scenario and a real shop-floor system will show the successful transfer of this method.

An analysis of unified framework standing behind a methodology in object oriented decision support system design has been analysed. First of all the consistency of the assumed knowledge bases describing an object (enterprise) and requests (standard options supporting a decision maker), respectively are examined. Then the knowledge base representation is transformed into representation of so called constraint satisfaction problem (CSP). Possible ways of the CSP decomposition as well as possibility of different programming languages application lead to a problem of searching for a distribution strategy which gives possibility to interact in an on-line mode.

In production engineering radical changes are taking place supported in new manufacturing paradigms and in technological developments. The increasing demand for meeting customer requirements and technological innovations have influenced the degree of flexibility built in the manufacturing system and its ability to respond in terms of cost, volume and time delivery. Taking the example of Portuguese mould making industry, this paper will analysed the main changes that have occurred in this industry and its ability to adapt to the availability of higher level of digital technologies and how they support new business models, extending their value adding chain.

Knowledge based methods in the domain of process and factory planning could lead to substantial savings for products with a high number of variants and production facilities. Although knowledge based approaches are already state of the art in the engineering and data management of complex products, these methods have not yet been applied to the planning of processes and production facilities so far. The extension of knowledge based methods to the domain of process and factory planning could lead to substantial savings for products with a high number of variants and production facilities. The objective of this paper is to demonstrate the state of the art in process planning with special focus on a possible integration with factory planning. Based on the literature review and the requirements of modeling data for the domain of process and resource planning, a methodology is derived and a prototypical solution based on commercially available software is demonstrated. The result is a knowledge based planning method for products, processes and the necessary production facilities.

Process orientation is a major concern nowadays. For this reason there have been great advances in business process modelling as means to better understand and promote organizational operations and evolution. However, organizational functions such as logistics, quality, finance, etc. still exist and strongly influence aspects like change processes, or the structuring of organizational units even if a “process culture” is established. This paper proposes a framework for integrating modelling, monitoring and learning aspects associated with the functional dimension of the enterprise. This framework is based on: (1) an ontology proposed (in another forthcoming paper) for the functional dimension of an organization; (2) the fundamental concepts: entity, role and activity, that are the base for current research work by other authors, on modelling other dimensions or concerns of an enterprise architecture. Also an example of application of the framework is presented as a proof of concept.

This paper presents an application based on digital enterprise technologies to support both the business globalization and service providing in small and medium sized companies highly focused in production competences. The requirements and functionalise are discussed and the application to support the work environment, communication and remote access to information and in-site knowledge is overviewed. The application was designed considering the current work procedures in tooling industry and it allows tool makers staff, in their usual workstation, to interact with their in-site colleagues, clients or any partner at distant places and discuss technical problems, accessing and having available all the required information

Although today a well-known Enterprise Resource Planning (ERP) System such as SAP can support many of the standard organization needs, the fact is that for many reasons most organizations prefer to change the ERP default configuration and/or complement the ERP with many other external applications, either existing or new ones. However, these external applications are still expensive to develop but especially to integrate with the ERP and even more expensive to change in order to support new business processes. In this paper we present an integration tool that we developed for the OutSystems platform called Integration Studio. This tool completely automates the task of integrating OutSystems applications with .Net assemblies and relational databases. In addition, the tool was designed with an extensibility philosophy and was already extended to support easy integrations with SAP and Java. Other technologies, such as the Lightweight Directory Access Protocol (LDAP), will follow soon. With Integration Studio, the OutSystems platform now supports not only the fast and easy creation and change of applications but also the easy integration of them with any other existing application in the organization. Furthermore, other non-OutSystems applications can also access the OutSystems platform (e.g. using Web Services) to easily integrate with any OutSystems or non- OutSystems applications. With Integration Studio, the OutSystems platform is now a fully automated Integrated Services Environment (ISE) that, unlike the existing products in the market, is extremely easy to learn and use.

In the Reverse Engineering process, scanned data digitised by various scanning systems from the component geometry is used to regenerate the original design information. CAD model creation from such data requires numerous stages of modelling processes. Several algorithms for the modelling processes were developed and verified in the earlier stages of this research. In this paper the automation of these algorithms into a unique CAD modelling system is introduced. The system user can create a complete CAD model by integration and minimum manipulation of the high resolution scanned data, obtained using a high accuracy Coordinate Measurement Machine with touch probe, and low resolution scanned data obtained using a high speed Laser Scanner, rapidly and accurately.

The “Parametric Prototype” has been developed as a tool for integrated parametric and physical shape representation to optimize styling and design. This tool will be applied in the early phases of the product development process at an appropriate level of detail, e.g. for the fast visualization of car parameters and proportions of the exterior car body. The development comprises a method that converses changes in the product model in a CAD system and the physical model bidirectional. Further the implementation of an interface between the physical shape presentation and the computer based representation has been realized.

This paper investigates the use of Virtual Reality and Human Simulation technologies for the ergonomic evaluation of manual assembly tasks. Within this concept, a virtual environment has been developed for the realistic representation of assembly stations into which digital humans can be imported and be used in order to evaluate assembly executions, in terms of ergonomics aspects. The industrial need lies on the reduction of process time and on the ergonomic optimization of the assembly workstations. The use of this environment enables the identification of critical steps, during an assembly execution that causes stress to humans and results in increased assembly times and over wearied operators. A real life assembly task of a commercial refrigerator has been simulated and presented in order for its environment capabilities to be demonstrated.