Scheduling of production systems

In practice most of the processes are batch type processes where the products are produced by the given sequence of steps (tasks) in the batch processes where supposed by the material flow is not continuous between tasks. In a scheduling problem equipment units are assigned to each task and the production order is determined for each equipment unit in the optimal way of an objective function.

• Different objective functions

  • Minimizing overall processing time for given amount of products

  • Maximizing profit in a given time horizon

  • Maximizing expected profit in uncertain market conditions

  • Minimizing total earliness, tardiness

• Different storage policies

  • Zero wait strategies

  • Storing in the equipment unit

  • Enough storage capacity to store all material

  • Dedicated storage vessels for materials

  • Shared storage vessels

• The scheduling problem can be combined with lots of other aspects like energy or waste water minimization

• Solving online scheduling problems

Automation of industrial processes

The control of most industrial processes and production systems requires information technology. Events in the production process can be catched by sensors or sensor networks. The signs of the sensors are usually got by programmable logic controllers (PLC) or microcontrollers. A controller calculated decision is performed by different equipments such as switches, motors, etc.

Research in pure mathematics -- Graphs and hypergraphs

Our research field includes several central topics from Discrete Mathematics. In particular, we study the abstract properties of graphs (networks) and hypergraphs (set systems) with the following emphases:

• Colorings of graphs and hypergraphs that is partitioning the underlying set into independent classes (or into classes which satisfy another given property)

• Extremal set theory

• Minimal transversals and maximal independent sets in graphs and hypergraphs

• Dominating sets in graphs and hypergraphs; lower and upper bounds on the minimum cardinality, related algorithms, and the competitive optimization versions (domination games)

Information retrieval (IR)

Information retrieval deals with the representation, storage, organization of, and access to information items. Its primary objective is to find unstructured documents from large collections that satisfies a user information need. Information retrieval research involves different theoretical models, together with extensive experimentation to develop more accurate, fast and advanced information retrieval and search techniques for a variety of applications.

Text mining

Text mining from textual databases is the process of extracting interesting and non-trivial patterns or knowledge from unstructured text documents.Text mining can help an organization derive potentially valuable business insights from text-based content such as word documents, email and postings on social media streams.