Hans-Joerg Kreowski

Hans-Joerg Kreowski
Universität Bremen | Uni Bremen · Computer Science

Dr.-Ing.

About

290
Publications
11,696
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4,706
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Introduction
As a theoretical computer scientist, my current research interests are the (mathematical) modeling and analysis of rule-based systems and graph transformation, in particular. Moreover, I am interested in computer and society. I am currently working on splitting/fusion grammars and reaction systems on one hand and a critical view on artificial intelligence and transhumanism on the other hand.
Additional affiliations
October 1982 - present
Universität Bremen
April 1974 - September 1982
Technische Universität Berlin
Education
April 1969 - April 1974
Technische Universität Berlin
Field of study
  • Mathematics

Publications

Publications (290)
Chapter
In this paper, we start a case study on the use and usefulness of graph transformation in modeling and analyzing games and puzzles beginning with logic puzzles. More explicitly, we consider Sudoku, Hashiwokakero, Arukone, and Maze aka Labyrinth. In these cases, the underlying data structures can be represented by graphs and the puzzles have start c...
Article
Fusion grammars are a novel approach to the generation of hypergraph languages. Context-dependent fusion grammars extend them in such a way that the application of fusion rules can be restricted by positive and negative context conditions. In this paper, we show that several variants of Petri nets can be transformed into these grammars such that th...
Article
Full-text available
In this paper, we propose a graph-transformational approach to swarm computation that is flexible enough to cover various existing notions of swarms and swarm computation, and it provides a mathematical basis for the analysis of swarms with respect to their correct behavior and efficiency. A graph transformational swarm consists of members of some...
Book
This book examines the contributions of the transhumanism approach to technology, in particular the contributed chapters are wary of the implications of this popular idea. The volume is organized into four parts concerning philosophical, military, technological and sociological aspects of transhumanism, but the reader is free to choose various rea...
Preprint
Full-text available
Graph-based reaction systems were recently introduced as a generalization of the intensely studied set-based reaction systems. They deal with simple edge-labeled directed graphs, and dynamic semantics of graph-based reaction systems is defined by graph surfing as a novel kind of graph transformation where, in a single surf step, reactions are appli...
Book
This book constitutes the refereed proceedings of the 12th International Conference on Subject-Oriented Business Process Management, S-BPM ONE 2020, held in Bremen, Germany, in December 2020. Due to the COVID-19 pandemic the conference was held online. The 10 full papers and 5 short papers were thoroughy reviewed and selected from 25 submissions. T...
Article
Full-text available
In the literature, one encounters the intensely studied classical set-based reaction systems and the more recently introduced generalization to graph-based reaction systems where the considered graphs are directed, simple, and edge-labeled. In this paper, we propose a categorical approach to reaction systems so that a wider spectrum of data structu...
Chapter
Full-text available
Humankind is on the transition to a supra-system of humanity, according to which social relationships – that organise the common good – are re-organised such that global challenges are kept below the threshold of a self-inflicted breakdown. In order to succeed, three conditions are imperative: (1) Global governance needs a global conscience that or...
Article
In this paper, we introduce graph-based reaction systems as a generalization of set-based reaction systems, a novel and well-investigated model of interactive computation. Graph-based reaction systems allow us to introduce a new methodology for graph transformation, which is not based on the traditional “cut, add, and paste” approach, but rather on...
Article
In this paper, we study reversible circuits as cascades of multi-target Toffoli gates. This type of gates allows to shift parts of a gate to the preceding gate within a circuit provided that a certain independence condition holds. It turns out that shifts decrease the so-called waiting degree such that shifting as long as possible always terminates...
Chapter
Splitting/fusion grammars were recently introduced as devices for the generation of hypergraph languages. Their rule application mechanism is inspired by basic operations of DNA computing. In this paper, we demonstrate that splitting/fusion grammars and well-known computational approaches based on DNA computing are closely related on a technical le...
Book
Beiträge auf dem Kolloquium „Emergente Systeme, Information und Gesellschaft – Problemstrukturen und Lösungsansätze“ Wolfgang Hofkirchner und Hans-Jörg Kreowski: Editorial Wolfgang Hofkirchner: Eine Informatik für eine globale nachhaltige Informationsgesellschaft Rainer E. Zimmermann: System, Materie, Information. Probleme der Grundlegung ihrer Beg...
Chapter
In this paper, we reconsider an old and simple notion of parallel graph transformation and point out various perspectives concerning the parallel generation of graph languages, the parallelization of graph algorithms, the parallel transformation of infinite graphs, and parallel models of computation.
Chapter
Abstract. In this paper, we introduce graph-based reaction systems as a generalization of set-based reaction systems, a novel and well-investigated model of interactive computation. Graph-based reaction systems allow us to introduce a novel methodology for graph transformation, which is not based on the traditional "cut, add, and paste" approach, b...
Article
Full-text available
Transhumanismus und Militär - Dossier Nr. 85 der Zeitschrift Wissenschaft & Frieden. Transhumanismus ist eine weltweite philosophisch-futuristische Bewegung mit dem Ziel, die physischen und intellektuellen Grenzen heutiger Menschen zu überwinden. Neben vielerlei zivilen Motiven, die von der Bekämpfung von Krankheiten bis zur Unsterblichkeit reichen...
Chapter
The use of decentralized control systems in the field of intralogistics offers high promises, but presents also various technical challenges. One of them is the development of adequate modeling approaches. Based on the problem of routing of automated guided vehicles (AGVs), this paper demonstrates how graph-transformational swarms can be used to mo...
Article
Transhumanism is an international philosophical and futuristic movement aiming to enhance the intellectual and physical capabilities of human beings beyond their current limits. It has gotten quite some drive and attention in the last 30 years. Transhumanists intend to employ already existing technologies such as artificial intelligence, robotics,...
Conference Paper
In this paper, we introduce the notion of fusion grammars as a novel device for the generation of (hyper)graph languages. Fusion grammars are motivated by the observation that many large and complex structures can be seen as compositions of a large number of small basic pieces. A fusion grammar is a hypergraph grammar that provides the small pieces...
Chapter
For a decade at least, a worldwide cyber armament race takes place; cyber attacks against all kinds of information and communication systems are a daily reality, and cyberwar becomes a growing threat. In this chapter, the military, political, and technological aspects of cyberwar are surveyed and discussed on one hand. On the other hand, the vision...
Article
Full-text available
In this paper, we propose to employ the framework of graph-transformational swarms for the modeling of dynamic logistic networks with decentralized processing and control. The members of a graph-transformational swarm act and interact in a common environment graph with massive parallelism of rule-based activities according to local control conditio...
Chapter
Full-text available
In this paper, we discuss the basic constraints and objectives of a unified logistics modeling language that allows to model dynamic logistic systems on various levels of concern from the requirements definition to their design and realization. It should, furthermore, support the compositionality and interoperability among all processes and other c...
Conference Paper
Reversible circuits provide the subject of a new promising direction of circuit design. Reversible circuits are cascades of reversible gates specifying bijective functions on Boolean vectors. As one encounters quite a variety of reversible gates in the literature, there are many classes of reversible circuits. Two main problems are considered: (1)...
Conference Paper
In this paper, we study reversible circuits as cascades of multi-target Toffoli gates. This new type of gates allows to shift parts of a gate to the preceding gate within a circuit provided that a certain independence condition holds. It turns out that shifts decrease the so-called waiting degree such that shifting as long as possible always termin...
Chapter
In this paper, we propose a framework for modeling of logistic systems with an emphasis on model transformation. Due to the complexity of logistic systems, their models are bound to consist of many heterogeneous components on various descriptive levels from the requirement definition to the platform-specific implementation. To cover these phenomena...
Conference Paper
The concept of graph-transformational swarms is a novel approach that offers a rule-based framework to model discrete swarm methods. This paper continues the research on graph-transformational swarms by focusing on a special type of members called stationary members. The stationary members are assigned to particular subgraphs of the considered envi...
Article
Full-text available
Production and logistics systems are part of a complex world with global sourcing and sales. In order to run production and logistics systems efficiently, plenty of different IT systems are needed. Thereby, production and logistics processes have to pass different systems with different purposes. In order to plan, control and coordinate such proces...
Conference Paper
Reversible circuits are intensively studied for some years as a promising alternative to conventional circuits. Mainly for illustrative purposes and in a rather informal way, they are often visually represented. This inspired us to a graph-transformational approach to reversible circuits. The first steps are documented in this paper with emphasis o...
Article
Graph transformation units are rule-based devices to model and compute relations between initial and terminal graphs. In this paper, they are generalized to graph tuple transformation units that allow one to combine different kinds of graphs into tuples and to process the component graphs simultaneously and interrelated with each other. Moreover, o...
Article
In this paper, we introduce and study polynomial graph transformability as a graph-transformational counterpart of the satisfiability problem of the propositional calculus.
Book
This book constitutes the proceedings of the 6th International Conference on Graph Transformations, ICGT 2012, held in Bremen, Germany, in September 2012. The 30 papers and 3 invited papers presented were carefully reviewed and selected from numerous submissions. The papers are organized in topical sections on behavioural analysis, high-level graph...
Conference Paper
In logistics and other application areas, one faces many intractable and NP-hard problems like scheduling, routing, packing, planning, and various kinds of optimization. Many of them can nicely and correctly be modeled by means of graph transformation. But a graph transformation engine fails to run the solutions properly because it does not have an...
Article
Full-text available
In this paper, graph multiset transformation is introduced and studied as a novel type of parallel graph transformation. The basic idea is that graph transformation rules may be applied to all or at least some members of a multiset of graphs simultaneously providing a computational step with the possibility of massive parallelism in this way. As a...
Article
Full-text available
Communities of autonomous units are devices for the visual modeling of interactive logistic processes. The framework is founded on rule-based graph transformation and allows specifying autonomous units in such a way that they can run in parallel and make their decision about future actions independently of each other. The usefulness of the framewor...
Chapter
In the world of logistics, one must deal with quite a variety of aspects including the interplay of production and transportation, the interoperation of trucks, trains, vessels and planes, the wide spectrum of used technologies like radio frequency identification, telematics, global positioning, and networking. Moreover most logistic affairs concer...
Book
The volume comprises the proceedings of the second International Conference on Dynamics in Logistics LDIC 2009. The scope of the conference was concerned with the identification, analysis, and description of the dynamics of logistic processes and networks. The spectrum reached from the planning and modelling of processes over innovative methods lik...
Conference Paper
Full-text available
Graph transformation units are rule-based devices to model graph algorithms, graph processes, and the dynamics of systems the states of which are represented by graphs. Given a graph, various rules are applicable at various matches in general, but not any choice leads to a proper result so that one faces the problem of nondeterminism. As countermea...
Conference Paper
Full-text available
There has been a growing interest in using the soft computing techniques for distributed data processing in monitoring systems during last years; wireless sensor network is an example which can be utilized to record and process the environmental conditions in transportation systems. In this paper, by using knowledge based soft computing techniques,...
Article
Full-text available
Graph transformation units are rule-based entities that allow to transform source graphs into target graphs via sets of graph transformation rules according to a control condition. The graphs and rules are taken from an underlying graph transformation approach. Graph transformation units specify model transformations whenever the transformed graphs...
Conference Paper
In this paper, we propose a new framework of model transformation that combines graph transformation with algebraic specification. While graph transformation is well-suited to describe the transformation of visual models, one can observe that models are often composite structures with visual, graphical and diagrammatic components accompanied by all...
Conference Paper
Communities of autonomous units are rule-based and graph-transformational devices to model processes that act and interact, move and communicate, cooperate and compete in a common environment. The autonomous units are independent of each other, and the environment may be large and structured in such a way that a global synchronization of process ac...
Article
Full-text available
This paper shows how a central part of the Unified Modeling Language (UML) can be integrated into a single visual semantic model. It discusses UML models composed of class, object, state, sequence and collaboration diagrams and presents an integrated semantics of these models. As formal basis the theoretically well-founded area of graph transformat...
Article
Full-text available
In this paper, we introduce the notion of a community of autonomous units as a rulebased and graph-transformational device to model processes that run interactively but independently of each other in a common environment. The main components of an autonomous unit are a set of rules, a control condition, and a goal. Every autonomous unit transforms...
Conference Paper
Communities of autonomous units are devices to model the interaction of independent processes in a rule-based and graphical way. In this paper, the framework is proposed to describe the interplay of players of a game following the intuition that a player is an autonomous unit playing the game according to the rules of the game but driven by its own...
Conference Paper
Full-text available
In this paper, graph multiset transformation is introduced and studied as a novel type of parallel graph transformation. The basic idea is that graph transformation rules may be applied to all or at least some members of a multiset of graphs simultaneously providing a computational step with the possibility of massive parallelism in this way. As a...
Conference Paper
Full-text available
In this paper, we give an overview of the framework of graph transformation units which provides syntactic and semantic means for analyzing, modeling, and structuring all kinds of graph processing and graph transformation.
Article
Full-text available
This paper investigates multiple alternatives to predict environmental parameters (temperature and relative humidity) inside an intelligent container with the aim of the supervision of cool chains. A wireless sensor network will help us to measure those parameters in some distributed points of the closed space. To achieve the aim of fault detection...
Book
Logistic problems can rarely be solved satisfyingly within one single scientific discipline. This cross-sectional character is taken into account by the Research Cluster for Dynamics in Logistics with a combination of economical, information and production technical and enterprise-oriented research approaches. In doing so, the interdisciplinary coo...
Conference Paper
Full-text available
Communities of autonomous units are being developed for formal specification and semantic analysis of systems of interacting and mobile components. The autonomous units of a community are rule-based, self-controlled, goal-driven, and operate and move in a common environment. We employ communities of autonomous units to model the dynamic pickup and...
Article
Full-text available
Looking at the whole logistic network, the structure of logistic processes becomes increasingly complex. Especially in transport logistics, atomisation of transportation processes, multimodal transport chains, international competition, changing ecological and legal constraints along with congestion of traffic infrastructure lead to highly dynamic...
Chapter
A precise mathematical approach to stepwise refinement of software systems is given within the framework of algebraic specifications. Since our new concept for the implementation of abstract data types — recently introduced in another paper — corresponds to a single refinement step, the composition problem for algebraic implementations is studied i...
Chapter
In this paper we introduce the notion of implementations of parameterized data types generalizing our algebraic implementation concept of actual types as studied in earlier papers. A typical example is the implementation of binary trees bintree(data), by strings with brackets bracketstring(data), where data is the common formal parameter part of bo...
Conference Paper
Full-text available
In this paper, we introduce the notion of a community of autonomous units as a rule-based and graph-transformational device to model processes that run interactively but independently of each other in a common environment. The emphasis of the approach is laid on the study of the formal semantics of a community as a whole and of each of its member u...
Conference Paper
Full-text available
In this paper, we introduce contextual hypergraph grammars, which generalize the total contextual string grammars. We study the position of the class of languages generated by contextual hypergraph grammars in comparison with graph languages generated by hyperedge replacement grammars and double-pushout hypergraph grammars. Moreover, several exampl...
Conference Paper
Full-text available
Communities of autonomous units are rule-based and graph-transformational devices to model data-processing systems that may consist of distributed and mobile components. The components may communicate and interact with each other, they may link up to ad-hoc networks. In this paper, we introduce and investigate the parallel-process semantics of comm...
Chapter
In this paper, we introduce and study the notion of collage grammars. A collage (in our sense) consists essentially of a set of parts being geometric objects and a set of hyperedges being subjects of further replacement. A set of collages represents a set of geometric patterns where each pattern is just the union of the parts of a collage. By overl...
Chapter
Collage grammars generate picture languages in a context-free way. The generating process is based on the replacement of atomic nonterminal items and can be seen as an adaptation of the notion of hyperedge replacement known from the area of context-free graph generation. While a pumping lemma holds for hyperedge replacement graph grammars and is qu...
Article
Full-text available
In this paper, some fundamental aspects of the semantics of rule-based systems are sketched and related to the semantics of visual models. A rule-based system comprises a set of rules and some control conditions including descriptions of initial and terminal configurations. Semantically, the rules specify a binary relation on configurations of some...
Conference Paper
A new concept for the implementation of abstract data types is proposed: Given algebraic specifications SPECO and SPEC1 of abstract data types ADTO and ADT1 an implementation of ADTO by ADT1 is defined separately on the syntactical level of specifications and on the semantical level of algebras. This concept is shown to satisfy a number of conceptu...
Chapter
Basing on the Church-Rosser Theorems in /EK 76b/ analysis and synthesis of parallel derivations in graph grammars are introduced. This allows specific, transparent transformations of derivation sequences, which can be used as elementary steps of algorithms acting on derivations, and the calculation rules for transformations presented in this paper...
Conference Paper
Jungle evaluation is proposed as a new graph rewriting approach to the evaluation of functional expressions and, in particular, of algebraically specified operations. Jungles — being intuitively forests of coalesced trees with shared substructures — are certain acyclic hypergraphs (or equivalently, bipartite graphs) the nodes and edges of which are...
Chapter
Full-text available
Consider a class C of hyperedge-replacement graph grammars and a numeric function on graphs like the number of edges, the degree (i.e., the maximum of the degrees of all nodes of a graph), the number of simple paths, the size of a maximum set of independent nodes, etc. Each such function induces a Boundedness Problem for the class C: Given a gramma...
Article
Full-text available
This chapter introduces rule-based graph transformation, which con-stitutes a well-studied research area in computer science. The chapter presents the most fundamental definitions and illustrates them with some selected examples. It presents also the concept of transformation units, which makes pure graph transfor-mation more feasible for specifica...
Article
In this paper we introduce a new hierarchical graph model to structure large graphs into small components by distributing the nodes (and, likewise, edges) into a hierarchy of packages. In contrast to other known approaches, we do not fix the type of underlying graphs. Moreover, our model is equipped with a rule-based transformation concept such tha...
Conference Paper
Full-text available
The aim of this paper is to introduce a modelling concept and structuring principle for rule-based systems the semantics of which is not restricted to a sequential behavior, but can be applied to various types of parallelism and concurrency. The central syntactic notion is that of a transformation unit that encapsulates a set of rules, imports othe...
Conference Paper
Full-text available
Inthispaper,weproposeanew,loose semanticsfor place/tran- sition nets based on transition systems and generalizing the reachability graph semantics. The loose semantics of a place/transition net reflects all its possible refinements and is given as a category of transition systems with alternative sequences of events over the net. The main result st...
Conference Paper
Full-text available
The concept of autonomous units to model distributed logistic processes and their interactions in a transport network is introduced. Autonomous units provide a general approach with rigorous semantics that allow the visual modelling of logistic processes in the transport domain in a systematic and structured way. Differing from existing models it e...
Article
Full-text available
In this short paper, the concept of autonomous units is introduced as a device to model logistic processes and their interaction and cooperation within a logistic network. The aim is to provide a general approach with rigorous semantics that allows the visual modelling of logistic processes in a systematic and structured way and supports the verifi...
Conference Paper
Full-text available
The concept of graph transformation units in its original sense is a structuring principle for graph transformation systems which allows the interleaving of rule applications with calls of imported units in a controlled way. The semantics of a graph transformation unit is a binary relation on an underlying type of graphs. In order to get a flex- ib...