Telling Experts from Spammers: Expertise Ranking in Folksonomies (2009)
Noll, Michael, Au Yeung, Ching Man, Gibbins, Nicholas, Meinel, Christoph, Shadbolt, Nigel
With a suitable algorithm for ranking the expertise of a user in a collaborative tagging system, we will be able to identify experts and discover useful and relevant resources through them. We...
On Measuring Expertise in Collaborative Tagging Systems (2009)
Au Yeung, Ching Man, Noll, Michael, Gibbins, Nicholas, Meinel, Christoph, Shadbolt, Nigel
Collaborative tagging systems such as Delicious.com provide a new means of organizing and sharing resources. They also allow users to search for documents relevant to a particular topic or for other...
Tele-Lab IT Security: A Means to Build Security Laboratories on the Web (2009)
Providing hands-on experience by live exercises is essential for current IT security education. Therefore, Tele-Lab IT security, a web-based training system, is being developed at the University of...
An e-Librarian Service that Understands Natural Language Questions from Students (2009)
Serge Linckels, Christoph Meinel, Thomas Engel
Abstract. In this paper we present an e-librarian service which is able to retrieve multimedia resources from a knowledge base in a more efficient way than by browsing through an index or by using a...
On Measuring Expertise in Collaborative Tagging Systems (2009)
Man Au Yeung, Ching, Noll, Michael, Gibbins, Nicholas, Meinel, Christoph, Shadbolt, Nigel
Collaborative tagging systems such as Delicious provide a new means of organizing and sharing resources. They also allow users to search for documents relevant to a particular topic or for other...
Meinel, Christoph (Hrsg.), Plattner, Hasso (Hrsg.), Döllner, Jürgen (Hrsg.) Et Al.
Design and Implementation of service-oriented architectures imposes a huge number of research questions from the fields of software engineering, system analysis and modeling, adaptability, and...
Retrieval Optimization of Pertinent Answers for NL Questions with the E-Librarian Service (2008)
Serge Linckels, Harald Sack, Christoph Meinel
Although educational content in the WWW is increasing dramatically, its usage in an educational environment is poor, mainly due to the fact that there is too much of (unreliable) redundant and not...
Burkhard Lüpken, Frank Losemann, Thomas Engel, Christoph Meinel
Abstract- Nowadays, almost all public administration plan to establish processes with electronic signatures. For such processes, there are no standardized system models with test cases. We are...
Christoph Meinel, Thorsten Theobald
Abstract. Ordered binary decision diagrams are an important data structure for the representation of Boolean functions. Typically, the underlying variable ordering is used as an optimization...
An e-Librarian Service that Understands Natural Language Questions from Students (2008)
Serge Linckels, Christoph Meinel, Thomas Engel
Abstract. In this paper we present an e-librarian service which is able to retrieve multimedia resources from a knowledge base in a more efficient way than by browsing through an index or by using a...
Web Search Personalization via Social Bookmarking and Tagging (2008)
Michael G. Noll, Christoph Meinel
Abstract. In this paper, we present a new approach to web search personalization based on user collaboration and sharing of information about web documents. The proposed personalization technique...
DAPHNE – A Tool for Distributed Web Authoring and Publishing 1 (2008)
Zhongdong Zhang, Andreas Heuer, Thomas Engel, Christoph Meinel
Web authoring and publishing in organizations / enterprises has become a more and more important and complex task. It has become a distributed, collaborative process performed by many users with less...
zusammengestellt von / edited by (2008)
German National, Committee International, Union History, Christoph Meinel, Wolfhard Weber, Bochum Regensburg, ...
(DFG) erstellt. Der Broschüre liegt eine CD-ROM mit einer PDF-Datei des vollständigen Textes bei. Diese Version kann auch von der Homepage des Nationalkomitees der IUHPS/DHS heruntergeladen werden:
Managing Distributed Personal Firewalls with Smart Data Servers (2008)
Ernst-georg Haffner, Uwe Roth, Andreas Heuer, Thomas Engel, Christoph Meinel
A Policy Language for Integrating Heterogeneous Authorization Policies (2008)
Abstract. In order to manage and enforce multiple heterogeneous authorization policies in distributed authorization environment, we defined the root policy specification language and its...
AN E-LIBRARIAN SERVICE THAT YIELDS PERTINENT RESOURCES FROM A MULTIMEDIA KNOWLEDGE BASE (2008)
Serge Linckels, Christoph Meinel
Abstract: In this paper we present an e-librarian service which is able to retrieve multimedia resources from a knowledge base in a more efficient way than by browsing through an index or by using a...
FZQSAT: A QSAT Solver for QBFs in Prenex NNF (A Useful Tool for Circuit Verification) (2008)
Mohammad Ghasemzadeh, Volker Klotz, Christoph Meinel
In this paper we present FZQSAT, which is an algorithm for evaluating quantified Boolean formulas presented in negation normal form (NNF). QBF is a language that extends propositional logic in such a...
Optimizing the Retrieval of Pertinent Answers for NL Questions with the E-Librarian Service (2008)
Serge Linckels, Harald Sack, Christoph Meinel
Abstract. There is a growing discrepancy between the creation of digital content and its actual employment and usefulness in a learning society. Technologies for recording lectures have become...
Representation and Evaluation of QBFs in Prenex-NNF (2008)
Mohammad Ghasemzadeh, Volker Klotz, Christoph Meinel
Theoretical and practical investigations have shown that some forms of reasoning such as belief revision, nonmonotonic reasoning, reasoning about knowledge, and STRIPS-like planning can be formulated...
Printed in Spain A NOVEL APPROACH TO E-LEARNING CONTENT CREATION (2008)
Proceedings Ii, International Conference Multimedia, J. Mesa González, Tongbo Chen, Mingchao Ma, ...
m-ICTE2003 www.formatex.org/micte2003/micte2003.htm
New Media for Teaching Applied Cryptography and Network Security (2008)
Ji Hu, Dirk Cordel, Christoph Meinel
Abstract. Considering that security education needs to train students to deal with security problems in real environments, we developed new media for teaching applied cryptography and network...
Fraunhofer Gesellschaft, Christoph Meinel, Thomas Engel, Christoph Meinel, Thomas Engel, Lutz Gollan, ...
T wie Trust T wie Trier T wie TI
The Importance of Link-Transformation and Link-Proposals for Hyperlink-Management Systems � (2008)
Andreas Heuer, Uwe Roth, Thomas Engel, Christoph Meinel
Abstract: This short paper emphasizes on a special aspect of hyperlink-management systems as part of online authoring systems. The transforming and adopting of links in HTML-files is very important....
A XML Format Secure Protocol--OpenSST (2008)
Xinhua Zhang, Chunyan Jiang, Wangjun Huang, Christoph Meinel
OpenSST (Open Simple Secure Transaction) is a free software project and aims to create an efficient, open and secure alternative to the secure proprietary transaction protocol. OpenSST uses XML...
ABSTRACT The “IT-summit-blog ” Case Harald (2008)
The first national IT-summit in Germany had the goal to communicate the common conviction and objective target of the German government as well as economic and scientific organizations, that Germany...
Teaching in the Cyber-Age: Technologies, Experiments, and Realizations (2008)
Serge Linckels, Christoph Meinel, Thomas Engel
Abstract: In this paper we describe the role of teachers in the cyber-age and how new teaching methods in a computer-based learning environment can foster exploratory learning. An overview of modern...
A SIMPLE APPLICATION OF DESCRIPTION LOGICS FOR A SEMANTIC SEARCH ENGINE ABSTRACT (2008)
Serge Linckels, Christoph Meinel
In this paper we present a simple application of Description Logics in order to improve the semantic search engine of a multimedia e-Learning tool. CHESt (Computer History Expert System) allows...
The Virtual Tele-TASK Professor—Semantic Search in Recorded Lectures ABSTRACT (2008)
Serge Linckels, Naouel Karam, Christoph Meinel
This paper describes our e-librarian service that understands students ’ complete questions in natural language and retrieves very few but pertinent learning objects, i.e., short multimedia...
Enhance OpenSST Protocol's Security with Smart Card (2008)
Smart Card, Xinhua Zhang, Alexandre Dulaunoy, Christoph Meinel
As an open source project, Open Simple Secure Transaction (OpenSST) protocol aims to be a secure and transactionoriented protocol for the unsecured network. At present a prototypes has been...
A Security Improved OpenSST Prototype Combining with Smart Card (2008)
Xinhua Zhang Christoph, Christoph Meinel, Alexandre Dulaunoy, Conostix S. A
Open Simple Secure Transaction (OpenSST) protocol aims to be a secure and transaction-oriented protocol for the unsecured network. OpenSST is a open source project, at present a simple prototype...
Tele-Lab IT-Security: An Architecture for an Online Virtual IT Security Lab (2008)
Christian Willems, Christoph Meinel
Recently, Awareness Creation in terms of ITsecurity has become a big thing – not only for enterprises.Campaigns for pupils try to highlight the importance of ITsecurity even in the user’s early...
Meinel, Christoph, Polze, A., Weske, M., Döllner, J.
Contents 1. Styling for Service-Based 3D Geovisualization Benjamin Hagedorn 2. The Windows Monitoring Kernel Michael Schöbel 3. A Resource-Oriented Information Network Platform for Global Design...
Erster Deutscher IPv6 Gipfel (2008)
Meinel, Christoph, Sack, Harald, Bross, Justus
Inhalt: KOMMUNIQUÉ GRUßWORT PROGRAMM HINTERGRÜNDE UND FAKTEN REFERENTEN: BIOGRAFIE & VOTRAGSZUSAMMENFASSUNG 1.) DER ERSTE DEUTSCHE IPV6 GIPFEL AM HASSO PLATTNER INSTITUT IN POTSDAM - PROF. DR....
Optimizing Partitioning of Transition Relations by Using High-Level Information (2007)
Christian Stangier, Fb Informatik, Ulrich Holtmann, Christoph Meinel
The computation of the reachable state set is a core task of optimization and formal verification of sequential systems like controllers or protocols. State exploration techniques based on OBDDs use...
Modeling Time and Document Aging for Request Prediction - One Step further (2007)
Ernst-georg Haffner, Uwe Roth, Thomas Engel, Christoph Meinel
An important problem of prediction algorithms is the treatment of document aging and the change in user request behavior. This paper proposes a possibility to model time in a standard prediction...
Probabilistic Symbolic Simulation and Verification with \Phi-OBDDs (2007)
Ordered Binary Decision Diagrams (OBDDs) have already proved useful in the verification of combinational and sequential circuits. Due to limitations of the descriptive power of OBDDs several more...
Integration of a Public Key Infrastructure in a Virtual University (2007)
Mariana Podestá, Christoph Meinel
Users in a virtual university normally gain access to the virtual campus and its resources using a valid username and password. Each resource may have a different passphrase that the user has to...
Link Proposals with Case-Based Reasoning Techniques (2007)
Ernst-georg Haffner, Uwe Roth, Andreas Heuer, Thomas Engel, Christoph Meinel
Abstract: In this paper, we will discuss the problem of proposing links for hypertexts based on Case-Based Reasoning (CBR) techniques. These proposals can be used in addition to traditional textual...
Matrix Rank Arguments for Proving Lower Bounds on the Size of Branching Programs (2007)
Christoph Meinel, Stephan Waack
This paper is structured as follows: In Section 1, the algebraically based concept of !-branching programs, !: IN \Gamma!R,
Adaptive Compression of Image Data (2007)
Sergei Hludov, Claus Schröter, Christoph Meinel
In this paper we will introduce a method of analyzing images, a criterium to differentiate between images, a compression method of medical images in digital form based on the classification of the...
Design and Implementation of a Certificate Authority Frontend (2007)
Name Mariana Podest, Mariana Podestá, Frank Losemann, Frank Losemann, Thomas Engel, Thomas Engel, ...
This paper can also be presented in Spanish
Techniques for Securing Networks against Criminal Attacks (2007)
In Proc International, Ernst-georg Haffner, Thomas Engel, Christoph Meinel
The main Internet security problems nowadays can be reduced to three major fields: Hackers have software programs that scan automatically networks for security weaknesses, more and more PC's are...
Dynamic Global Rebuilding (2007)
Christoph Meinel, Anna Slobodová
Ordered binary decision diagrams (OBDDs) have proved their usability in many CAD applications. The size of an OBDD may crucially depend on the order in which the variables occur. The optimization of...
A Reducibility Concept for Problems Defined in Terms of Ordered Binary Decision Diagrams (2007)
Christoph Meinel, Anna Slobodova
Reducibility concepts are fundamental in complexity theory. Usually, they are defined as follows: A problem \Pi is reducible to a problem \Sigma if \Pi can be computed using a program or device for...
this paper we present an Internet based solution, that focuses on the area of OBDD heuristics. Section 2 gives a discussion of the need for Web interfaces and explains the specifics of the OBDD...
Ein Fallbeispiel aus dem CAD--Schaltkreisentwurf (2007)
ogramme mit Hilfe von Proceedings of GISI'95 Z urich, Informatik aktuell, Springer, 339--346 bin aren Signalen bin ar verschl usselte Daten miteinander verkn upfen und somit die Behandlung s...
Upper and Lower Bounds for Certain Graph-Accessibility-Problems on Bounded Alternating (2007)
Branching Programs Christoph, Mathematik Informatik, Trierer Forschungsberichte, Trierer Forschungsberichte, Fachbereich Iv, Fachbereich Iv, ...
Due to a theory of communication within branching programs that has been developed in [MW91] exponential lower bounds on the size of ordinary, nondeterministic, parity and other sorts of branching...
Christoph Meinel Fb, Mathematik Informatik, Trierer Forschungsberichte, Fachbereich Iv, Christoph Meinel, Christoph Meinel
An important motivation to investigate the GRAPH-ACCESSIBILITY -PROBLEM (GAPN ) is its property to provide natural complete problems for logarithmic space-bounded complexity classes (see e. g. [?])....
Algorithmic Considerations for (2007)
Ordered Binary Decision Diagrams (OBDDs) have already proved useful in the process of electronic design automation. Due to limitations of the descriptive power of OBDDs more general models of Binary...
The "Log Rank" Conjecture for Modular Communication Complexity (2007)
Christoph Meinel Fb, Christoph Meinel, Stephan Waack
The "log rank" conjecture consists in the question how exact the deterministic communication complexity of a problem can be determinied in terms of algebraic invarants of the communication...
DAPHNE - A Tool for Distributed Web Authoring and Publishing (2007)
Zhongdong Zhang, Andreas Heuer, Thomas Engel, Christoph Meinel
Web authoring and publishing in organizations / enterprises has become a more and more important and complex task. It has become a distributed, collaborative process performed by many users with less...
ABSTRACT Modeling of Time and Document Aging for Request Prediction- One Step Further ∗ (2007)
Ernst-georg Haffner, Uwe Roth, Thomas Engel, Christoph Meinel
An important problem of prediction algorithms is the treatment of document aging and the change in user request behavior. This paper proposes a possibility to model time in a standard prediction...
Design and Implementation of a Certificate Authority Frontend Extended abstract (2007)
Name Mariana Podestá, Mariana Podestá, Frank Losemann, Frank Losemann, Thomas Engel, Thomas Engel, ...
Requirements for the presentation: overhead projector or video projector This paper can also be presented in Spanish
Introduction Link Proposals with Case-Based Reasoning Techniques * (2007)
Ernst-georg Haffner, Uwe Roth, Andreas Heuer, Thomas Engel, Christoph Meinel
A Practical Approach to Store DICOM-conform Presentations of Radiological Images (2007)
Lutz Vorwerk, Christoph Meinel
Engraneisasystemwhichisusedtoprepareandshowpresentations of radiological images as well as the reports which belong to these images. The presentations with Engrane will be performed by displaying...
Heuristics for-OBDD Minimization (2007)
Ordered Binary Decision Diagrams (OBDDs) have already proved useful in the process of electronic design automation. Due to limitations of the descriptive power of OBDDs more general models of Binary...
Managing Distributed Personal Firewalls with Smart Data Servers * (2007)
Ernst-georg Haffner, Uwe Roth, Andreas Heuer, Thomas Engel, Christoph Meinel
ABSTRACT THE INTERNAL WORKFLOW (2007)
Middle-tier architectures have to fulfill many requirements. These requirements are growing with the different versions of the middle-tier architecture. To allow a flexible extension of the...
Improving XOR-Node Placement for-OBDDs (2007)
Ordered Binary Decision Diagrams (OBDDs) have already proved useful in the process of electronic design automation. Due to limitations of the descriptive power of OBDDs more general models of Binary...
Advanced Studies on Link Proposals and Knowledge Retrieval of Hypertexts with CBR * (2007)
Ernst-georg Haffner, Andreas Heuer, Uwe Roth, Thomas Engel, Christoph Meinel
Abstract. In this paper, several problems in associating hyperlinks to text and the diverse possibilities to overcome these problems are discussed. At the current stage, an important aspect is...
OVERCOMING TECHNICAL FRUSTATIONS IN DISTANCE EDUCATION: TELE-TASK* (2007)
Christoph Meinel, Volker Schillings, Vanessa Walser
Modern information technologies are transforming the way people learn. E-learning provides new possibilities for personalized learning at home or in the workplace, reduces the need for costly...
A Complete Solution for Highly Secure Data Exchange: LockKeeper and its Advancements (2007)
Feng Cheng, Christoph Meinel, Thomas Engel
Abstract-The Lock-Keeper is a new network security solution which can provide secure data transfers between two different networks without having to establish a direct physical connection. By means...
Variable Reordering for -OBDDs (2007)
Ordered Binary Decision Diagrams (OBDDs) have already proved useful in the process of electronic design automation. Due to limitations of the descriptive power of OBDDs more general models of Binary...
OBDD Heuristics Online Evaluation of OBDD-Heuristics via the Internet (2007)
Today the Internet oers the highly interesting possibility of standardized and global communication without a need for special hardware or expensive infrastructure. As the Internet will most likely...
Case Study: Manipulating \Phi-OBDDs by Means of Signatures (2007)
We present a case study concerning manipulation of \Phi-OBDDs based on a probabilistic equivalence test. Efficient Boolean function manipulation requires efficient algorithms for Boolean synthesis as...
Authors Mariana Podestá (2007)
Mariana Podestá, Mariana Podestá, Christoph Meinel, Christoph Meinel, Christoph Meinel
Copyright © 2000
A Hyperlink-Proposal Mechanism to Exemplify Cognitive Algorithms for Web-Applicationse (2007)
Abstract After a brief description of an algorithm for proposing hyperlinks, this article focuses on a general class of \Cognitive Algorithms " to improve Web-applications. The idea of the...
Signed Preservation Of Online References (2007)
Andreas L. Heuer, Frank Losemann, Christoph Meinel
Abstract: Since online-available documents are more and more outclassing paper based documents, the use of online references is constantly growing. Online references suffer strongly from their often...
Heuristics for -OBDD Minimization (2007)
Ordered Binary Decision Diagrams (OBDDs) have already proved useful in the process of electronic design automation. Due to limitations of the descriptive power of OBDDs more general models of Binary...
a b s t r a c t In computer aided design of very large scale integrated circuits (CAD for VLSI) Ordered Binary Decision Diagrams (OBDDs) [1] have been established as the state-of-the-art data...
Managing Distributed Personal Firewalls with Smart Data Servers (2007)
Ernst-georg Haffner, Uwe Roth, Andreas Heuer, Thomas Engel, Christoph Meinel
Abstract: Modern security architectures tend to become more and more complex. Not only the chances to improve Web applications using several data channels and diverse (TCP-)ports are very promising,...
Overcoming Ordering Restrictions for Synthesizing Binary Decision Diagrams (2007)
Christoph Meinel, Harald Sack, Christan Stangier
Many problems in computer-aided design of highly integrated circuits (CAD for VLSI) can be transformed to the task of manipulating objects over nite domains. The eciency of these operations depends...
Improving XOR-node placements for ⊕-OBDDs (2007)
Ordered Binary Decision Diagrams (OBDDs) have already proved useful in the process of electronic design automation. Due to limitations of the descriptive power of OBDDs more general models of Binary...
A Data Structure for Multiple-Valued Functions (2007)
Trierer Forschungsberichte, Fachbereich Iv, Mathematik Informatik, Mathematik Informatik, Harald Sack, Harald Sack, ...
Electronic copies of technical reports are available: Via FTP: Host ftp.informatik.uni-trier.de, directory /pub/reports
Routing Based Workflow for Construction of Distributed Applications * (2007)
Wanjun Huang, Xinhua Zhang, Uwe Roth, Christoph Meinel
Dynamic reconfiguration is absorbing more and more research focus for its increasing demand in inconstant distributed application. In this paper we propose a routing based workflow to model the...
Segmentation and Quantification of Brain Tumor (2007)
Chunyan Jiang, Xinhua Zhang, Wanjun Huang, Christoph Meinel
Abstract – Nowadays, the inside situation could be obtained by medical machines, such as Computed Tomography (CT), Magnetic Resonance Imaging (MRI) scanner, etc. These noninvasive diagnosis means...
Implement role based access control with attribute certificates (2007)
Nowadays more and more activities are performed over the Internet. But as more people are involved in the transaction circle, security and authorization control becomes one of the biggest concerns....
A Flexible Middleware Platform with Piped (2007)
Wanjun Huang, Uwe Roth, Christoph Meinel
Abstract. Middleware emerges as an excellent solution for the complicated distributed computing application. But as the appearance of new devices and new applications, the inflexibility of...
Security in Telemedicine – Certificates and Digital Identity Cards* (2007)
Torsten Becker, Christoph Meinel
Abstract — In health care confidentiality of data is an ethical necessity. Hence data must be stored and transmitted according to high level security standards, at best under control of the...
Feng Cheng, Paul Ferring, Christoph Meinel
a The idea of data transfer by physically severed connections has been applied in a simple realization of the Lock-Keeper technology, the SingleGate Lock-Keeper system. By means of it, the...
Resolving ambiguities in the semantic interpretation of natural language questions (2006)
Serge Linckels, Christoph Meinel
Abstract. Our project is about an e-librarian service which is able to retrieve multimedia resources from a knowledge base in a more efficient way than by browsing through an index or by using a...
A virtual machine architecture for creating IT-security laboratories (2006)
Hu, Ji, Cordel, Dirk, Meinel, Christoph
E-learning is a flexible and personalized alternative to traditional education. Nonetheless, existing e-learning systems for IT security education have difficulties in delivering hands-on experience...
T.: Student’s perception of a semantic search engine (2005)
Monique Reichert, Serge Linckels, Christoph Meinel, Thomas Engel
This paper focuses on the question how students appreciate and value the possibility to query a multimedia knowledge base by entering complete questions instead of keywords. We aim at examining how...
A Simple Solution for an Intelligent Librarian System (2005)
Serge Linckels, Christoph Meinel
In this paper, we describe a method to retrieve documents based on the semantics of a user's question, rather than on keywords. It is based on domain ontology and on RDF (Resource Description...
Linckels, Serge, Meinel, Christoph
1 Introduction 1.1 Project formulation 1.2 Our contribution 2 Pedagogical Aspect 4 2.1 Modern teaching 2.2 Our Contribution 2.2.1 Autonomous and exploratory learning 2.2.2 Human machine interaction...
Grayscale image matting and colorization (2004)
Tongbo Chen, Yan Wang, Volker Schillings, Christoph Meinel
Fig. 1. Grayscale image matting and colorization results. A and B are the input grayscale images to our algorithm, while A ′
Meinel,Christoph, Zimmermann,Herbert, Schmitt,Heike, Haeberlen,Ulrich
The synthesis of a specific isotopomer, C6D4H(ortho)-H(ortho)D4C6 of biphenyl is reported. The intramolecular dipolar coupling of the protons leads to a well-resolved single-crystal proton nuclear...
Meinel, Christoph, Zimmermann, Herbert, Schmitt, Heike, Haeberlen, Ulrich
The synthesis of a specific isotopomer, C6D4H(ortho)-H(ortho)D4C6 of biphenyl is reported. The intramolecular dipolar coupling of the protons leads to a well-resolved single-crystal proton nuclear...
T-Cube: A Multimedia Authoring System for eLearning (2003)
Mingchao Ma, Volker Schillings, Tongbo Chen, Christoph Meinel
The Flood-Gate Principle - a Hybrid Approach to a High Security Solution (2003)
Ernst-georg Haffner, Thomas Engel, Christoph Meinel
Abstract. The classical role of a firewall consists in protecting a computer network against attacks from the outside world, especially the Internet. Firewalls are often expensive, hard to configure...
A Tutoring System for IT Security (2003)
Ji Hu, Michael Schmitt, Christian Willems, Christoph Meinel
Abstract: Due to the many vulnerabilities of today's computer systems, IT security education has become an important topic. For that reason, a new tutoring system is developed at the Institute...
C.: “BDDs, Horn Clauses and Resolution (2003)
Mohammad Ghasemzadeh, Christoph Meinel
In this research we present the utilization of BDDs in representing propositional logic programs and implementing the refutation by resolution deduction method. A logic program is a collection of...
The Flood-Gate Principle - a Hybrid Approach to a High Security Solution (2003)
Ernst-georg Haffner, Thomas Engel, Christoph Meinel
Abstract. The classical role of a firewall consists in protecting a computer network against attacks from the outside world, especially the Internet. Firewalls are often expensive, hard to configure...
The Flood-Gate Principle - a Hybrid Approach to a High Security Solution (2003)
Thomas Engel, Christoph Meinel
. The classical role of a firewall consists in protecting a computer network against attacks from the outside world, especially the Internet. Firewalls are often expensive, hard to configure and they...
The Flood-Gate Principle - a Hybrid Approach to a High Security Solution (2003)
Ernst-georg Haffner, Thomas Engel, Christoph Meinel
. The classical role of a firewall consists in protecting a computer network against attacks from the outside world, especially the Internet. Firewalls are often expensive, hard to configure and they...
The Flood-Gate Principle - a Hybrid Approach to a High Security Solution (2003)
Ernst-georg Haffner, Thomas Engel, Christoph Meinel
. The classical role of a firewall consists in protecting a computer network against attacks from the outside world, especially the Internet. Firewalls are often expensive, hard to configure and they...
Design and Implementation of a PHP-based Web Server for the Tele-Lab IT Security (2003)
Michael Schmitt, Ji Hu, Christoph Meinel, Michael Schmitt, Ji Hu, Christoph Meinel
The Tele-Lab IT Security project aims at specifying and implementing a web-based, intelligent tutoring system that allows computer science students, system administrators, and end users to get...
Secure Transfer of Digital Images and Related Data (2002)
Vorwerk, Lutz, Jiang, Chunyan, Meinel, Christoph
Communication in medicine and healthcare is very important. A standard used for communication is DICOM. It integrates medical images with patient related data. This data describes some attributes of...
A proposal for trust model: Independent trust intermediary service (ITIS (2002)
Reliable, distributed applications based on Internet, such as e-commerce system rely heavily on trust path among involved parties. This article introduces an efficient trust model based trust...
Digital signatures for automobiles (2002)
Dr. Iur Lutz Gollan, Prof Dr, Christoph Meinel
www.ti.fhg.de Abstract: Identifying and tracking vehicles is of major importance for today’s logistics. The common non-electronic solutions are both easy to forge and difficult to use over...
Mubarakzjanov R., Nonlinear sifting of decision diagrams (2002)
Christoph Meinel, Rustam Mubarakzjanov
We propose a new algorithm for the optimization of decision diagrams that combines the ef-ciency of sifting and the power of transformations. We show that the new algorithm is applicable to large...
Stangier: “Modular Partitioning and Dynamic Conjunction Scheduling in Image Computation “,in (2002)
Christoph Meinel, Christian Stangier
Image computation is the core task in any formal verification applications like reachable states computation or model checking. In OBDD-based image computation a partitioned representation of the...
Ordererd Binary Decision Diagrams in Electronic Design Automation, chapter 11 (2002)
Randal E. Bryant, Christoph Meinel
Abstract Ordered Binary Decision Diagrams (OBDDs) play a key role in the automated synthesis and formal verication of digital systems. They are the state-of-the-art data structure for representing...
Standardizing DICOM File and Rendering 3-D Medical Image (2002)
Chunyan Jiang, Lutz Vorwerk, Christoph Meinel
this paper, we will discuss about how to display 3D image by using the approach of standardization. H@UCP9# T#hqh...qv"vt# DICOM standard has developed for a few years (1). In this latest...
A proposal for trust model: Independent trust intermediary service (ITIS (2002)
Reliable, distributed applications based on Internet, such as e-commerce system rely heavily on trust path among involved parties. This article introduces an efficient trust model based trust...
Course management in the twinkle of an eye - lcms: a professional course management system (2002)
In this paper we describe a course management system for university lectures and lab courses, called LCMS. Started as a simple registration tool for students, signing up for lab courses and...
Schmitt,Heike, Zimmermann,Herbert, Körner,O., Stumber,Michael, Meinel,Christoph, Haeberlen,Ulrich
Using calcium formate, α-Ca(DCOO)2, as a test sample, we explore how precisely deuteron quadrupole coupling (QC) and chemical shift (CS) tensors Q and can currently be measured. The error...
Schmitt,Heike, Zimmermann,Herbert, Körner,O., Stumber,Michael, Meinel,Christoph, Haeberlen,Ulrich
Using calcium formate, α-Ca(DCOO)2, as a test sample, we explore how precisely deuteron quadrupole coupling (QC) and chemical shift (CS) tensors Q and can currently be measured. The error...
Schmitt,Heike, Zimmermann,Herbert, Körner,O., Stumber,Michael, Meinel,Christoph, Haeberlen,Ulrich
Using calcium formate, α-Ca(DCOO)2, as a test sample, we explore how precisely deuteron quadrupole coupling (QC) and chemical shift (CS) tensors Q and can currently be measured. The error...
Telematik: Grenzenlose Anwendungen - Forschung für die Praxis (2001)
BIK 2001 Tagung vom 4. - 6. April 2001; Vortrag Christoph Meinel; Mittwoch, 04.04.2001
Telematik: Grenzenlose Anwendungen - Forschung für die Praxis (2001)
BIK 2001 Tagung vom 4. - 6. April 2001; Vortrag Christoph Meinel; Mittwoch, 04.04.2001
Schmitt, Heike, Zimmermann, Herbert, Körner, O., Stumber, Michael, Meinel, Christoph, Haeberlen, Ulrich
Using calcium formate, α-Ca(DCOO)2, as a test sample, we explore how precisely deuteron quadrupole coupling (QC) and chemical shift (CS) tensors Q and can currently be measured. The error...
Schmitt, Heike, Zimmermann, Herbert, Körner, O., Stumber, Michael, Meinel, Christoph, Haeberlen, Ulrich
Using calcium formate, α-Ca(DCOO)2, as a test sample, we explore how precisely deuteron quadrupole coupling (QC) and chemical shift (CS) tensors Q and can currently be measured. The error...
Schmitt, Heike, Zimmermann, Herbert, Körner, O., Stumber, Michael, Meinel, Christoph, Haeberlen, Ulrich
Using calcium formate, α-Ca(DCOO)2, as a test sample, we explore how precisely deuteron quadrupole coupling (QC) and chemical shift (CS) tensors Q and can currently be measured. The error...
Hierarchical Image Computation with Dynamic Conjunction Scheduling (2001)
Christoph Meinel, Christian Stangier
Image computation is the core operation for optimization and formal verification of sequential systems like controllers or protocols. State exploration techniques based on OBDDs use a partitioned...
Stangier “Hierarchical Image Computation with Dynamic Conjunction Scheduling “Proc (2001)
Christoph Meinel, Christian Stangier
Image computation is the core operation for optimization and formal verification of sequential systems like controllers or protocols. State exploration techniques based on OBDDs use a partitioned...
A new partitioning scheme for improvement of image computation (2001)
Christoph Meinel, Fb Informatik, Christian Stangier
Image computation is the core operation for optimization and formal verification of sequential systems like controllers or protocols. State exploration techniques based on OBDDs use a partitioned...
The dynamic disorder of azulene: A single crystal deuterium nuclear magnetic resonance study (2000)
Bräuninger,Thomas, Poupko,Raphy, Luz,Zeev, Gutsche,Peter, Meinel,Christoph, Zimmermann,Herbert, ...
Deuterium nuclear magnetic resonance measurements on single crystals of azulene, specifically deuterated in the 1 and 3 positions, are reported. The quadrupole coupling tensor of these deuterons was...
The dynamic disorder of azulene: A single crystal deuterium nuclear magnetic resonance study (2000)
Bräuninger,Thomas, Poupko,Raphy, Luz,Zeev, Gutsche,Peter, Meinel,Christoph, Zimmermann,Herbert, ...
Deuterium nuclear magnetic resonance measurements on single crystals of azulene, specifically deuterated in the 1 and 3 positions, are reported. The quadrupole coupling tensor of these deuterons was...
The dynamic disorder of azulene: A single crystal deuterium nuclear magnetic resonance study (2000)
Bräuninger, Thomas, Poupko, Raphy, Luz, Zeev, Gutsche, Peter, Meinel, Christoph, Zimmermann, Herbert, ...
Deuterium nuclear magnetic resonance measurements on single crystals of azulene, specifically deuterated in the 1 and 3 positions, are reported. The quadrupole coupling tensor of these deuterons was...
The dynamic disorder of azulene: A single crystal deuterium nuclear magnetic resonance study (2000)
Bräuninger, Thomas, Poupko, Raphy, Luz, Zeev, Gutsche, Peter, Meinel, Christoph, Zimmermann, Herbert, ...
Deuterium nuclear magnetic resonance measurements on single crystals of azulene, specifically deuterated in the 1 and 3 positions, are reported. The quadrupole coupling tensor of these deuterons was...
Heidelberg, Universiẗat, Diss., 2000.
Optimizing Requests for the Smart Data Server; As (2000)
Ernst-georg Haffner, Uwe Roth, Thomas Engel, Christoph Meinel
The growing complexity of the Web information flow makes it necessary to improve Client/Server communication. In order to efficiently maintain heterogeneous and fast changing data types and different...
A Proposal for a Combination of Compression and Encryption (2000)
Lutz Vorwerk, Thomas Engel, Christoph Meinel
This paper describes how to integrate encryption in an algorithm which uses wavelets to compress data. Wavelets are more useful in image compression than other methods. This is because the definition...
What do hyperlink-proposals and request-prediction have in common (2000)
Ernst-georg Haffner, Uwe Roth, Andreas Heuer, Thomas Engel, Christoph Meinel
Abstract. This paper focuses on fundamental similarities between proposing links for hypertexts and predicting user-requests. It briefly outlines the theoretical background of both categories of...
Improving the Quality of Information-Flow with the Smart Data Server (2000)
Uwe Roth, Thomas Engel, Christoph Meinel
Nowadays, we face the continually growing importance of information: it is quickly becoming our most valuable resource. The Smart Data Server improves the quality of information by combining...
Web Site Design Using a Web-Based Authoring and Publishing System (2000)
Zhongdong Zhang, Uwe Roth, Thomas Engel, Christoph Meinel
Web authoring and publishing has become a daily task for almost every enterprise or organization. One big question is how the Web authoring and publishing can be organized or coordinated in such a...
Optimizing Requests For The Smart Data Server (2000)
Ernst-georg Haffner, Uwe Roth, Thomas Engel, Christoph Meinel
The growing complexity of the Web information flow makes it necessary to improve Client/Server communication. In order to efficiently maintain heterogeneous and fast changing data types and different...
Representation of Multiple-Valued Functions with Mod-p Decision Diagrams (2000)
Harald Sack, Elena Dubrova, Christoph Meinel
Multiple-valued logic allows us to formulate problems by using symbolic variables which are often more naturally associated with the problem speci cation than the variables obtained by a binary...
Speeding Up Symbolic Model Checking by Accelerating Dynamic Variable Reordering (2000)
Christoph Meinel, Christian Stangier
Symbolic Model checking based on OBDDs is a widely used technique in verication of sequential circuits, reactive systems or protocols. As the size of the OBDDs and also the computation time depends...
Speeding Up Image Computation by using RTL Information (2000)
Christoph Meinel, Fb Informatik, Christian Stangier
Image computation is the core operation for optimization and formal verification of sequential systems like controllers or protocols. State exploration techniques based on OBDDs use a partitioned...
Speeding Up Image Computation by using RTL Information (2000)
Christoph Meinel, Christian Stangier, Fb Informatik
. Image computation is the core operation for optimization and formal verication of sequential systems like controllers or protocols. State exploration techniques based on OBDDs use a partitioned...
Optimizing Requests For The Smart Data Server (2000)
In Proc Applied, Ernst-georg Haffner, Uwe Roth, Thomas Engel, Christoph Meinel
The growing complexity of the Web information flow makes it necessary to improve Client/Server communication. In order to efficiently maintain heterogeneous and fast changing data types and different...
Advanced Studies on Link Proposals and Knowledge Retrieval of Hypertexts with CBR (2000)
Ernst-georg Haffner, Andreas Heuer, Uwe Roth, Thomas Engel, Christoph Meinel
. In this paper, several problems in associating hyperlinks to text and the diverse possibilities to overcome these problems are discussed. At the current stage, an important aspect is knowledge...
Speeding Up Symbolic Model Checking by Accelerating Dynamic Variable Reordering (2000)
Christoph Meinel, Christian Stangier
Symbolic Model checking is a widely used technique in sequential verication. As the size of the OBDDs and also the computation time depends on the order of the input variables, the verication may...
Techniques for Securing Networks against Criminal Attacks (2000)
Ernst-georg Haffner, Thomas Engel, Christoph Meinel
The main Internet security problems nowadays can be reduced to three major fields: Hackers have software programs that scan automatically networks for security weaknesses, more and more PC's are...
Mod-p Decision Diagrams: A Data Structure for Multiple-Valued Functions (2000)
Harald Sack, Elena Dubrova, Christoph Meinel
Multiple-valued decision diagrams (MDDs) give a way of approaching problems by using symbolic variables which are often more naturally associated with the problem statement than the variables...
Speeding up symbolic model checking by accelerating dynamic variable reordering (2000)
Symbolic Model checking is a widely used technique in sequential verification. As the size of the OBDDs and also the computation time depends on the order of the input variables, the verification may...
Etrillard,J., Meinel,Christoph, Odin,C., Zimmermann,Herbert, Toudic,J. C., Ameline,J. C.
Nuclear magnetic resonance (NMR) experiments, 35Cl nuclear quadrupole resonance (NQR) and 2H NMR, have been performed close to the displacive normal-incommensurate phase transition in the organic...
Etrillard,J., Meinel,Christoph, Odin,C., Zimmermann,Herbert, Toudic,J. C., Ameline,J. C.
Nuclear magnetic resonance (NMR) experiments, 35Cl nuclear quadrupole resonance (NQR) and 2H NMR, have been performed close to the displacive normal-incommensurate phase transition in the organic...
Etrillard, J., Meinel, Christoph, Odin, C., Zimmermann, Herbert, Toudic, J. C., Ameline, J. C.
Nuclear magnetic resonance (NMR) experiments, 35Cl nuclear quadrupole resonance (NQR) and 2H NMR, have been performed close to the displacive normal-incommensurate phase transition in the organic...
Etrillard, J., Meinel, Christoph, Odin, C., Zimmermann, Herbert, Toudic, J. C., Ameline, J. C.
Nuclear magnetic resonance (NMR) experiments, 35Cl nuclear quadrupole resonance (NQR) and 2H NMR, have been performed close to the displacive normal-incommensurate phase transition in the organic...
An Approach to Distributed Functionality The Smart Data Server (1999)
Uwe Roth, E.G. Haffner, Thomas Engle, Christoph Meinel
: This paper introduces a new kind of Java-server, the Smart Data Server (SDS). It offers the accessing of data with function-calls to SDS-networks. This allows the building of lean clients with the...
Application Driven Variable Reordering and an Example Implementation in Reachability Analysis (1999)
Christoph Meinel, Klaus Schwettmann
Variable reordering is the main approach to minimize the size of Ordered Binary Decision Diagrams. But despite the huge effort spent, up to now, to design different reordering heuristics, their...
Algorithmic Considerations for ⊕-OBDD Reordering (1999)
Ordered Binary Decision Diagrams (OBDDs) have already proved useful in the process of electronic design automation. Due to limitations of the descriptive power of OBDDs more general models of Binary...
One Step Further: Extending Electronic Submission Into the Reviewing Process (1999)
Mathematik Informatik, Trierer Forschungsberichte, Trierer Forschungsberichte, Fachbereich Iv, Fachbereich Iv, Jochen Bern, ...
Modern information technologies have vastly improved the efficiency of document handling, and provide additional features and functionalities. In most cases, this improvement was realized by simply...
Algorithmic Considerations for ⊕-OBDD Reordering (1999)
Ordered Binary Decision Diagrams (OBDDs) have already proved useful in the process of electronic design automation. Due to limitations of the descriptive power of OBDDs more general models of Binary...
Sample method for minimization of OBDDs (1998)
This paper contributes to the solution of the minimization problem of Ordered Binary Decision Diagrams by means of variable reordering. We suggest a new heuristic that is based on sampling. A small...
⊕-OBDDs - a BDD Structure for Probabilistic Verification (1998)
Ordered Binary Decision Diagrams (OBDDs) have already proved useful in the verification of combinational and sequential circuits. Due to limitations of the descriptive power of OBDDs several more...
Sample Method for Minimization of OBDDs (1998)
Anna Slobodova, Christoph Meinel
This paper contributes to the solution of the minimization problem of Ordered Binary Decision Diagrams by means of variable reordering. We suggest a new heuristic that is based on sampling. A small...
Speeding Up Symbolic Model Checking (1998)
Christoph Meinel, Christian Stangier
Model checking is a widely used technique in verification of sequential circuits, reactive systems, protocols, etc. Ordered Binary Decision Diagrams (OBDDs) allow a symbolic representation of the...
Sample Method for Minimization of OBDDs (1998)
Anna Slobodov'a, Christoph Meinel
This paper contributes to the solution of the minimization problem of Ordered Binary Decision Diagrams by means of variable reordering. We suggest a new heuristic that is based on sampling. A small...
Electronic Colloquia: Idea And Practice (1998)
Jochen Bern, Christoph Meinel, Harald Sack, Fb Iv Informatik
The scientific community, especially the more computer related fields of science like computer science and mathematics, have not only been doing research in information technology, they have...
Do we really need common variable orders for synthesizing OBDDs? (1998)
Mathematik Informatik, Trierer Forschungsberichte, Trierer Forschungsberichte, Fachbereich Iv, Fachbereich Iv, Christoph Meinel
OBDDs have already proved useful in the verification of combinatorial and sequential circuits. But for the...
⊕-OBDDs - a BDD Structure for Probabilistic Verification (1998)
Christoph Meinel, H. Sack, Harald Sack
Ordered Binary Decision Diagrams (OBDDs) have already proved usefull in the verification of combinational and sequential circuits. Due to limitaions of the descriptive power of OBDDs several more...
Function Decomposition and Synthesis Using Linear Sifting (1998)
Christoph Meinel, Fabio Somenzi, Thorsten Theobald
In order to simplify a synthesis task for particularly hard functions it is sometimes inevitable to decompose the function in a preprocessing step. We propose a new algorithm for automatically...
Email Fmeinel, Christoph Meinel, Harald Sack
Ordered Binary Decision Diagrams (OBDDs) have already proved useful in the verification of combinational and sequential circuits. Due to limitations of the descriptive power of OBDDs several more...
Mathematik Informatik, Trierer Forschungsberichte, Fachbereich Iv, Christoph Meinel, Christoph Meinel, Thorsten Theobald, ...
Many problems in computer-aided design of highly integrated circuits (CAD for VLSI) can be transformed to the task of manipulating objects over finite domains. The efficiency of these operations...
The WWW meets EDA: Usability evaluation of OBDD-heuristics via the Internet (1998)
Mathematik Informatik, Trierer Forschungsberichte, Trierer Forschungsberichte, Fachbereich Iv, Fachbereich Iv, Christoph Meinel, ...
We present an approach for the evaluation of OBDD-heuristics over the Internet. We explain why there is a genuine need for the possibility of evaluating the power of new methods (e.g. heuristics)...
Application Driven Variable Reordering and an Example Implementation in Reachability Analysis (1998)
Christoph Meinel, Mathematik Informatik, Trierer Forschungsberichte, Trierer Forschungsberichte, Fachbereich Iv, Fachbereich Iv
Variable reordering is the main approach to minimize the size of Ordered Binary Decision Diagrams. But despite the huge effort spent, up to now, to design different reordering heuristics, their...
⊕-OBDDs - a BDD Structure for Probabilistic Verification (1998)
Trierer Forschungsberichte, Fachbereich Iv, Christoph Meinel, Harald Sack, Harald Sack
s and 1/TechReports/FullText Via WWW: URL http://www.informatik.uni-trier.de/Reports/List Via email: Send a mail to ftpmail@ftp.informatik.uni-trier.de, subject 'MAIL ME CLEAR', body...
Increasing Efficiency of Symbolic Model Checking by Accelerating Dynamic Variable Reordering (1998)
Mathematik Informatik, Trierer Forschungsberichte, Trierer Forschungsberichte, Fachbereich Iv, Fachbereich Iv, Christoph Meinel, ...
Model checking is a widely used technique in verification of sequential circuits, reactive systems, protocols, etc. Ordered Binary Decision Diagrams (OBDDs) allow a symbolic representation of the...
Accelerating OBDD-Minimization by Means of Structural and Semantical Properties (1998)
Christoph Meinel, Anna Slobodová, Mathematik Informatik, Trierer Forschungsberichte, Trierer Forschungsberichte, Fachbereich Iv, ...
In many different applications in computer science, the representation of Boolean functions is done in terms of Ordered Binary Decision Diagrams (OBDD). This is particulary true in the field of...
Linear sifting of decision diagrams (1997)
We propose a new algorithm, called linear sifting, for the optimization of decision diagrams that combines the e-ciency of sifting andthepower of linear transformations. We showthatthenew algorithm...
Linear sifting of decision diagrams (1997)
We propose a new algorithm, called linear sifting, for the optimization of decision diagrams that combines the e-ciency of sifting andthepower of linear transformations. We showthatthenew algorithm...
Case Study: Manipulating ...-OBDDs by Means of Signatures (1997)
We present a case study concerning manipulation of ...-OBDDs based on a probabilistic equivalence test. Efficient Boolean function manipulation requires efficient algorithms for Boolean synthesis as...
Speeding up Variable Reordering of OBDDs (1997)
Christoph Meinel, Anna Slobodova
In this paper, we suggest a block-restricted sifting strategy which is based on the restriction of Rudell's sifting to certain blocks of variables. The application of this strategy results in a...
Linear Sifting of Decision Diagrams (1997)
Christoph Meinel, Fabio Somenzi, Thorsten Theobald
We propose a new algorithm, called linear sifting, for the optimization of decision diagrams that combines the efficiency of sifting and the power of linear transformations. We show that the new...
On the Influence of the State Encoding on OBDD-Representations of Finite State Machines (1997)
Christoph Meinel, Thorsten Theobald
. Ordered binary decision diagrams are an important data structure for the representation of Boolean functions. Typically, the underlying variable ordering is used as an optimization parameter. When...
Speeding up Variable Reordering of OBDDs (1997)
Christoph Meinel, Anna Slobodova
The use of Ordered Binary Decision Diagrams (OBDDs) as a representation of Boolean functions brought essential progress in many different applications. The optimization of the OBDD-size by the choice...
Speeding up Variable Reordering of OBDDs (1997)
Christoph Meinel, Anna Slobodová
this paper, we investigate the subfunctions' profile as a structural attribute of a given OBDD. From the profile, we derive an information which variables should be kept in one block. Based on...
Speeding up Variable Reordering of OBDDs (1997)
Mathematik Informatik, Trierer Forschungsberichte, Fachbereich Iv, Christoph Meinel, Christoph Meinel
this paper, we investigate the subfunctions' profile as a structural attribute of a given OBDD. From the profile, we derive an information which variables should be kept in one block. Based on...
Block-Restricted Reordering - Extended Experiments (1997)
Christoph Meinel, Anna Slobodová, Peter Willems, Mathematik Informatik, Trierer Forschungsberichte, Trierer Forschungsberichte, ...
this report is to summarize and evaluate our experimental work with different variants of the method. We extend the method in many different ways: we allow a small overlapping of blocks, as well as...
Function Decomposition and Synthesis Using Linear Sifting (1997)
Mathematik Informatik, Trierer Forschungsberichte, Fachbereich Iv, Fabio Somenzi, Thorsten Theobald, Christoph Meinel, ...
In order to simplify a synthesis task for particularly hard functions it is sometimes inevitable to decompose the function in a preprocessing step. We propose a new algorithm for automatically...
Case Study: Manipulating ⊕-OBDDs by Means of Signatures (1997)
Ch. Meinel, H. Sack, Mathematik Informatik, Trierer Forschungsberichte, Fachbereich Iv, Christoph Meinel, ...
We present a case study concerning manipulation of \Phi-OBDDs based on a probabilistic equivalence test. Efficient Boolean function manipulation requires efficient algorithms for Boolean synthesis as...
Mathematik Informatik, Trierer Forschungsberichte, Trierer Forschungsberichte, Fachbereich Iv, Fachbereich Iv, Christoph Meinel, ...
The demand for formal verification of communication protocols is increasing since the use of distributed systems is still rapidly growing. Ordered binary decision diagrams (OBDDs) are widely and...
Linear Sifting of Decision Diagrams (1997)
Mathematik Informatik, Trierer Forschungsberichte, Fachbereich Iv, Fabio Somenzi, Thorsten Theobald, Christoph Meinel, ...
We propose a new algorithm, called linear sifting, for the optimization of decision diagrams that combines the efficiency of sifting and the power of linear transformations. We show that the new...
Some Heuristics for Generating Tree-like FBDD Types (1996)
Reduced ordered binary decision diagrams (OBDDs) are nowadays the state-of-theart representation scheme for Boolean functions in Boolean manipulation. Recent results have shown that it is possible to...
The "Log Rank" Conjecture for Modular Communication Complexity (1996)
Christoph Meinel, Stephan Waack
. The "log rank" conjecture consists of the question how exactly the deterministic communication complexity of a problem can be determined in terms of algebraic invariants of the...
Local Encoding Transformations for Optimizing OBDD-Representations of Finite State Machines (1996)
Christoph Meinel, Thorsten Theobald
Ordered binary decision diagrams are the state-of-the-art representation of switching functions. In order to keep the sizes of the OBDDs tractable, heuristics and dynamic reordering algorithms are...
Christoph Meinel, Anna Slobodová, Mathematik Informatik, Trierer Forschungsberichte, Trierer Forschungsberichte, Fachbereich Iv, ...
Reducibility concepts are fundamental in complexity theory. Usually, they are defined as follows: A problem \Pi is reducible to a problem \Sigma if \Pi can be computed using a program or device for...
State Encodings and OBDD-Sizes (1996)
Mathematik Informatik, Trierer Forschungsberichte, Fachbereich Iv, Thorsten Theobald, Thorsten Theobald, Christoph Meinel, ...
Ordered binary decision diagrams (OBDDs) have proven to be a useful tool in the automatic verification of finite state machines. The link between OBDDs and finite state machines is established by the...
A Reducibility Concept for Problems Defined in Terms of Ordered Binary Decision Diagrams (1996)
Reducibility concepts are fundamental in complexity theory. Usually, they are defined as follows: A problem \Pi is reducible to a problem \Sigma if \Pi can be computed using a program or device for...
Local Encoding Transformations for Optimizing OBDD-Representations of Finite State Machines (1996)
Mathematik Informatik, Trierer Forschungsberichte, Trierer Forschungsberichte, Fachbereich Iv, Fachbereich Iv, Christoph Meinel, ...
Ordered binary decision diagrams are the state-of-the-art representation of switching functions. In order to keep the sizes of the OBDDs tractable, heuristics and dynamic reordering algorithms are...
Global Rebuilding of OBDDs -- Avoiding Memory Requirement (1995)
Abstract. It is well-known that the size of an ordered binary decision diagram (OBDD) may depend crucially on the order in which the variables occur. In the paper, we describe an implementation of an...
Lower Bounds for the Modular Communication Complexity of Various Graph Accessibility Problems (1995)
Christoph Meinel, Theoretische Informatik, Fachbereich Iv, Stephan Waack
. We investigate the modular communication complexity of the graph accessibility problem GAP and its modular counting versions MODk--GAP, k 2. Due to arguments concerning variation ranks and certain...
Global Rebuilding of OBDDs - Avoiding Memory Requirement Maxima (1995)
Jochen Bern, Christoph Meinel, Anna Slobodová
It is well-known that the size of an ordered binary decision diagram (OBDD) may depend crucially on the order in which the variables occur. In the paper, we describe an implementation of an...
Christoph Meinel, Stephan Waack
this paper we consider the probabilistic majority acception mode in which a protocol
Efficient OBDD-Based Boolean Manipulation in CAD Beyond Current Limits (1995)
We present the concept of TBDD's which considerably enlarges the class of Boolean functions that can be efficiently manipulated in terms of OBDD's. It extends the idea of using domain...
Global Rebuilding of OBDDs - Avoiding Memory Requirement Maxima (1995)
. It is well-known that the size of an ordered binary decision diagram (OBDD) may depend crucially on the order in which the variables occur. In the paper, we describe an implementation of an...
Efficient OBDD-Based Boolean Manipulation in CAD Beyond Current Limits (1995)
Jochen Bern, Christoph Meinel, Anna Slobodová
We present the concept of TBDD's which considerably enlarges the class of Boolean functions that can be efficiently manipulated in terms of OBDD's. It extends the idea of using domain...
Efficient OBDD-Based Boolean Manipulation in CAD Beyond Current Limits (1995)
Mathematik Informatik, Trierer Forschungsberichte, Trierer Forschungsberichte, Fachbereich Iv, Fachbereich Iv, Jochen Bern Christoph, ...
We present the concept of TBDD's which considerably enlarges the class of Boolean functions that can be efficiently manipulated in terms of small size OBDD's. This is done by applying the...
Efficient OBDD-Based Boolean Manipulation in CAD Beyond Current Limits (1995)
Mathematik Informatik, Trierer Forschungsberichte, Trierer Forschungsberichte, Fachbereich Iv, Fachbereich Iv, Jochen Bern, ...
We present the concept of TBDD's which considerably enlarges the class of Boolean functions that can be efficiently manipulated in terms of small size OBDD's. This is done by applying the...
Boolean Manipulation with Free BDD's. First Experimental Results. (1994)
Jochen Bern, Jordan Gergov, Christoph Meinel
It is shown that Free Binary Decision Diagrams (FBDD's), with respect to a predefined type, ffl provide a canonical representation and ffl allow efficient solutions of the basic tasks in Boolean...
Boolean Manipulation with Free BDDs. An Application in Combinational Logic Verification. (1994)
Jordan Gergov, Christoph Meinel
INTRODUCTION By means of hardware description languages, circuits can be described at a very high level of abstraction which allows the designer to specify the behavior of a circuit beforehand...
Boolean Manipulation with Free BDD's. First Experimental Results. (1994)
Jochen Bern, Jordan Gergov, Christoph Meinel
It is shown that Free Binary Decision Diagrams (FBDD's), with respect to a predefined type, ffl provide a canonical representation and ffl allow efficient solutions of the basic tasks in Boolean...
Electronic Colloquium on Computational Complexity (1994)
The Mobius Function, Christoph Meinel, Lehrstuhl Theoretische Informatik, Fachbereich Iv Informatik, Stephan Waack
. We prove that the modular communication complexity of the undirected graph connectivity problem UCONN equals \Theta(n), in contrast to the well-- known \Theta(n log n) bound in the deterministic...
Boolean Manipulation with Free BDD's. First Experimental Results. (1994)
Mathematik Informatik, Trierer Forschungsberichte, Fachbereich Iv, Jochen Bern Jordan, Jochen Bern, Jordan Gergov, ...
It is shown that Free Binary Decision Diagrams (FBDD's), with respect to a predefined type, ffl provide a canonical representation and ffl allow efficient solutions of the basic tasks in Boolean...
Efficient Boolean Manipulation with OBDD's Can be Extended to FBDD's (1994)
Jordan Gergov And, Trierer Forschungsberichte, Fachbereich Iv, Jordan Gergov, Jordan Gergov, Christoph Meinel, ...
OBDD's are the state--of--the--art data structure for Boolean function manipulation since basic tasks of Boolean manipulation such as testing equivalence, satisfiability, or tautology, and...
Some Heuristics for Generating Tree-like FBDD Types (1994)
Mathematik Informatik, Trierer Forschungsberichte, Fachbereich Iv, Jochen Bern, Jochen Bern, Christoph Meinel, ...
Reduced ordered binary decision diagrams (OBDD's) are nowadays the state-of-the-art representation scheme for Boolean functions in Boolean manipulation. Recent results have shown that it is...
The Möbius Function, Variations Ranks, and. . . (1994)
Mathematik Informatik, Trierer Forschungsberichte, Fachbereich Iv, Christoph Meinel, Christoph Meinel, Lehrstuhl Theoretische Informatik, ...
We prove that the modular communication complexity of the undirected graph connectivity problem UCONN equals \Theta(n), in contrast to the well--known \Theta(n log n) bound in the deterministic case...
A Unifying Theoretical Background for Some BDD-based Data Structures (1994)
Mathematik Informatik, Anna Slobodová, Trierer Forschungsberichte, Trierer Forschungsberichte, Fachbereich Iv, Fachbereich Iv, ...
Abstract In the paper, we propose a general concept (in what follows denoted by TBDD) for Boolean functions manipulation that is based on cube transformations. The basic idea is to manipulate a...
Efficient Boolean Manipulation with OBDD's Can be Extended to FBDD's (1994)
Trierer Forschungsberichte, Fachbereich Iv, Jordan Gergov, Jordan Gergov, Christoph Meinel, Christoph Meinel, ...
OBDD's are the state--of--the--art data structure for Boolean function manipulation since basic tasks of Boolean manipulation such as testing equivalence, satisfiability, or tautology, and...
Separating Complexity Classes Related to Bounded Alternating omega-Branching Programs (1993)
Christoph Meinel, Stephan Waack
. By means of algebraical rank arguments we derive some exponential lower bounds on the size of bounded alternating !-branching programs. Together with some polynomial upper bounds these lower bounds...
Mod-2-OBDD's A Generalization of OBDD's and EXOR-Sum-of-Products (1993)
Jordan Gergov, Christoph Meinel
We present a data structure --- the Mod--2--OBDD's that considerably extend OBDD's (ordered binary decision diagrams) as well as ESOP's (EXOR--sum--of-- products). Many Boolean...
Christoph Meinel, Stephan Waack
In the following we investigate the computational complexity of various !-GRAPH ACCESSIBILITY PROBLEMs on the most general restricted type of !-branching programs for which, up to now, exponential...
Frontiers of Feasible and Probabilistic Feasible Boolean Manipulation with Branching Programs (1993)
Jordan Gergov, Christoph Meinel
Abstract. A central issue in the solution of many computer aided design problems is to find concise representations for circuit designs and their functional specification. Recently, a restricted type...
Combinational Logic Verification with FBDDs (1993)
Jordan Gergov And, Mathematik Informatik, Trierer Forschungsberichte, Fachbereich Iv, Jordan Gergov, Jordan Gergov, ...
OBDD's are the state--of--the--art data structure for Boolean function manipulation. For an excellent survey see [Bry92]. It is well known that OBDD's are restricted free BDD's...
Combinational Logic Verification with FBDDs (1993)
Mathematik Informatik, Trierer Forschungsberichte, Fachbereich Iv, Jordan Gergov, Jordan Gergov, Christoph Meinel, ...
OBDD's are the state--of--the--art data structure for Boolean function manipulation. For an excellent survey see [Bry92]. It is well known that OBDD's are restricted free BDD's...
Mod-2-OBDD's - A Generalization of OBDD's and EXOR-Sum-of-Products (1993)
Trierer Forschungsberichte, Fachbereich Iv, Jordan Gergov, Jordan Gergov, Christoph Meinel, Christoph Meinel, ...
We present a data structure --- the Mod--2--OBDD's that considerably extend OBDD's (ordered binary decision diagrams) as well as ESOP's (EXOR--sum--of-- products). Many Boolean...
Boolean Manipulation with Free BDD's. First Experimental Results. (1993)
Mathematik Informatik, Trierer Forschungsberichte, Fachbereich Iv, Jochen Bern, Jochen Bern, Jordan Gergov, ...
It is shown that Free Binary Decision Diagrams (FBDD's), with respect to a predefined type, ffl provide a canonical representation and ffl allow efficient solutions of the basic tasks in Boolean...
Analysis and Manipulation of Boolean Functions in Terms of Decision Graphs (1992)
Jordan Gergov, Christoph Meinel
. We investigate the question whether and to what extend the solution of central tasks of digital logic circuit design of a given Boolean function f benefits from a representation of f in terms of...
Structure and Importance of Logspace-MOD-Classes (1992)
Gerhard Buntrock, Carsten Damm, Ulrich Hertrampf, Christoph Meinel
. We refine the techniques of Beigel, Gill, Hertrampf [4] who investigated polynomial time counting classes, in order to make them applicable to the case of logarithmic space. We define the...
Analysis and Manipulation of Boolean Functions in Terms of Decision Graphs (1992)
Mathematik Informatik, Trierer Forschungsberichte, Fachbereich Iv, Jordan Gergov, Jordan Gergov, Christoph Meinel, ...
Abstract We investigate the question whether and to what extend the solution of central tasks of digital logic circuit design of a given Boolean function f benefits from a representation of f in...
Mathematik Informatik, Trierer Forschungsberichte, Fachbereich Iv, Christoph Meinel, Christoph Meinel
An important motivation to investigate the GRAPH-ACCESSIBILITY -PROBLEM (GAPN ) is its property to provide natural complete problems for logarithmic space-bounded complexity classes (see e. g. [?])....
Mathematik Informatik, Trierer Forschungsberichte, Trierer Forschungsberichte, Fachbereich Iv, Fachbereich Iv, Christoph Meinel, ...
Due to a theory of communication within branching programs that has been developed in [MW91] exponential lower bounds on the size of ordinary, nondeterministic, parity and other sorts of branching...
Modified branching programs and their computational power. (1988)
Berlin, Akad. d. Wiss. d. DDR, Diss. B, 1988 (Nicht f.d. Austausch).
Über die durch Kodierungen induzierte Hierarchie von Umwelten und Labyrinthen. (1982)
Berlin, Humboldt-Univ., Diss. A, 1982.
Binary Decision Diagrams and the Multiple Variable Order Problem
Gianpiero Cabodi Stefano, Stefano Quer, Christoph Meinel, Christian Stangier
Ordered Binary Decision Diagrams (OBDDs) are the first choice in manipulating and representing Boolean functions in CAD. Since the size of an OBDD heavily depends on the chosen variable order, much...
On Relations Between Counting Communication Complexity Classes
Carsten Damm Fb, Carsten Damm, Matthias Krause, Lehrstuhl Informatik Ii, Christoph Meinel, ...
We develop upper and lower bound arguments for counting acceptance modes of communication protocols. A number of separation results for counting communication complexity classes is established. This...
Binary Decision Diagrams and the Multiple Variable Order Problem
Gianpiero Cabodi, Stefano Quer, Christoph Meinel, Harald Sack, Anna Slobodová, Christian Stangier
Ordered Binary Decision Diagrams (OBDDs) are the first choice in manipulating and representing Boolean functions in CAD. Since the size of an OBDD heavily depends on the chosen variable order, much...
On Relations Between Counting Communication Complexity Classes
Carsten Damm, Matthias Krause, Seminargebaude A, Christoph Meinel, ...
We develop upper and lower bound arguments for counting acceptance modes of communication protocols. A number of separation results for counting communication complexity classes is established. This...
mit Hilfe von bin aren Signalen bin ar verschl usselte Daten miteinander verkn upfen und somit die Behandlung s amtlicher zu l osender Probleme in bin ar verschl usselter Form voraussetzt. So einfach...