Adam Malik

Self-optimising Production Systems

One of the central success factors for production in high-wage countries is the solution of the conflict that can be described with the term “planning efficiency”. Planning efficiency describes the relationship between the expenditure of planning and the profit generated by these expenditures. From the viewpoint of a successful business management, the challenge is to dynamically find the optimum between detailed planning and the immediate arrangement of the value stream. Planning-oriented approaches try to model the production system with as many of its characteristics and parameters as possible in order to avoid uncertainties and to allow rational decisions based on these models. The success of a planning-oriented approach depends on the transparency of business and production processes and on the quality of the applied models. Even though planning-oriented approaches are supported by a multitude of systems in industrial practice, an effective realisation is very intricate, so these models with their inherent structures tend to be matched to a current stationary condition of an enterprise. Every change within this enterprise, whether inherently structural or driven by altered input parameters, thus requires continuous updating and adjustment. This process is very cost-intensive and time-consuming; a direct transfer onto other enterprises or even other processes within the same enterprise is often impossible. This is also a result of the fact that planning usually occurs a priori and not in real-time. Therefore it is hard for completely planning-oriented systems to react to spontaneous deviations because the knowledge about those naturally only comes a posteriori.

Hierarchical feature clustering for content-based retrieval in medical image databases

In this paper we describe the construction of hierarchical feature clustering and show how to overcome general problems of region growing algorithms such as seed point selection and processing order. Access to medical knowledge inherent in medical image databases requires content-based descriptions to allow non-textual retrieval, e.g., for comparison, statistical inquiries, or education. Due to varying medical context and questions, data structures for image description must provide all visually perceivable regions and their topological relationships, which poses one of the major problems for content extraction. In medical applications main criteria for segmenting images are local features such as texture, shape, intensity extrema, or gray values. For this new approach, these features are computed pixel-based and neighboring pixels are merged if the Euclidean distance of corresponding feature vectors is below a threshold. Thus, the planar adjacency of clusters representing connected image partitions is preserved. A cluster hierarchy is obtained by iterating and recording the adjacency merging. The resulting inclusion and neighborhood relations of the regions form a hierarchical region adjacency graph. This graph represents a multiscale image decomposition and therefore an extensive content description. It is examined with respect to application in daily routine by testing invariance against transformation, run time behavior, and visual quality For retrieval purposes, a graph can be matched with graphs of other images, where the quality of the matching describes the similarity of the images.

Control of Dynamically Inherent Biological Processes in Cell Technology : Adaptive strategies for automated cell culture

The cultivation of human cells for diagnostic or biomedical applications is an interesting topic for the automation industry. However, classical automation concepts using an imperative programming paradigm reach their limits because of the inherent dynamical behavior of donor specific cells. In particular sophisticated cell culture processes, such as many stem cell technologies, have still to be executed manually, which renders them labor intensive and causes varying cell quality. In contrast to classical products, which for example are made of metal or plastic, living cells in culture are subject to changes in growth and functional properties depending on internal or external stimuli. Therefore, constant observation of the cells over extended periods of time is necessary. The evaluation of these observations serves as a basis for decision-making and online process adaptation. Finally, process adaptation leads to adjustments in scheduling. This paper presents a novel concept of rule-based modeling of cell culture processes, process adaption and dynamic scheduling. The concept was validated using a general process chain including the most common decision situation within a cell cultivation process.

Saving energy on shop floor control level: Prerequisites for energy-related scheduling within manufacturing execution systems

Energy efficiency is becoming an important topic for the manufacturing industry. Nowadays the unique features of production systems like precision, endurance, flexibility and initial costs must be extended by the energy efficiency. Using different control strategies on shop floor control level promises energy savings and prevention of unwanted high power peaks. This paper focuses on the investigation of prerequisites required to implement energy saving on shop floor control level within a manufacturing execution system. Electrical energy measuring methods together with evaluation heuristics and energy consumption models for robots and machine tools are shown. The concepts are validated using a production scenario based on a machine tool, two robots and a band conveyor. An application of the energy saving methods for manufacturing execution systems is shown.

Model-based assembly control concept

Production cells are typically built up of many heterogeneous components which are controlled by a central unit such as a standard programmable logic controller. Engineering of such cell controllers is usually based on an imperative programming paradigm. All possible decision situations are defined manually and coded offline, which is an acceptable method for simple or fixed recurring automation tasks. Implementing complex control and adaptation strategies however leads to disproportionately high engineering efforts, which incur whenever process changes are required. This paper presents a modelbased assembly control concept and a cell control engineering methodology. The concept was validated using a micro-slab laser assembly process within a multi-robot assembly cell.

Howtool – Verfahrensübergreifende Technologieplanung

Kurzfassung Die wachsende Komplexität der Technologieplanung wird ohne eine geeignete Softwareunterstützung für den Planer zunehmend schwerer zu bewältigen und damit ineffizient. In einem ersten Ansatz zur Bewältigung dieser Herausforderungen haben das Werkzeugmaschinenlabor WZL an der RWTH Aachen und die Forschungsvereinigung Programmiersprachen für Fertigungseinrichtungen e.V. ein Forschungsprojekt durchgeführt. In diesem Rahmen wurde eine Softwarestruktur entwickelt, die es ermöglicht, dem Planer auf Basis von interpretiertem Erfahrungswissen und deterministischen Ausschlusskriterien eine Liste möglicher zu verwendender Werkzeuge vorzuschlagen und diese gemäß ihrer Eignung zu gewichten.