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Graph-based Visualization of Requirements Relationships

Philipp Heim, Steffen Lohmann, Kim Lauenroth, Jürgen Ziegler
2008 2008 Requirements Engineering Visualization  
Understanding the relationships between requirements is important in order to understand the requirements themselves. Existing requirements management tools mainly use lists, tables, trees, and matrices to visualize requirements and their interrelations. However, all these visualization forms have a limited capability to show multiple relationships of different types. In this paper, we propose to extend traditional requirements analysis and management by a graphbased visualization that allows
more » ... represent multidimensional relations in a direct and flexible way. In particular, we propose a special presentation form that enables the exploration of requirements along their relationships and facilitates understanding of dependencies between requirements.
doi:10.1109/rev.2008.2 fatcat:jzx7cc3r3rgnze4vyrw4qdo4ca


Philipp Heim, Steffen Lohmann, Davaadorj Tsendragchaa, Thomas Ertl
2011 Proceedings of the 7th International Conference on Semantic Systems - I-Semantics '11  
Querying the Semantic Web and analyzing the query results are often complex tasks that can be greatly facilitated by visual interfaces. A major challenge in the design of these interfaces is to provide intuitive and efficient interaction support without limiting too much the analytical degrees of freedom. This paper introduces SemLens, a visual tool that combines scatter plots and semantic lenses to overcome this challenge and to allow for a simple yet powerful analysis of RDF data. The scatter
more » ... plots provide a global overview on an object collection and support the visual discovery of correlations and patterns in the data. The semantic lenses add dimensions for local analysis of subsets of the objects. A demo accessing DBpedia data is used for illustration.
doi:10.1145/2063518.2063543 dblp:conf/i-semantics/HeimLTE11 fatcat:nq5toph65vcufmv3ldal3af6wy

H_2 Pseudo-Optimal Reduction of Structured DAEs by Rational Interpolation [article]

Philipp Seiwald and Alessandro Castagnotto and Tatjana Stykel and Boris Lohmann
2018 arXiv   pre-print
In this contribution, we extend the concept of H_2 inner product and H_2 pseudo-optimality to dynamical systems modeled by differential-algebraic equations (DAEs). To this end, we derive projected Sylvester equations that characterize the H_2 inner product in terms of the matrices of the DAE realization. Using this result, we extend the H_2 pseudo-optimal rational Krylov algorithm for ordinary differential equations to the DAE case. This algorithm computes the globally optimal reduced-order
more » ... l for a given subspace of H_2 defined by poles and input residual directions. Necessary and sufficient conditions for H_2 pseudo-optimality are derived using the new formulation of the H_2 inner product in terms of tangential interpolation conditions. Based on these conditions, the cumulative reduction procedure combined with the adaptive rational Krylov algorithm, known as CUREd SPARK, is extended to DAEs. Important properties of this procedure are that it guarantees stability preservation and adaptively selects interpolation frequencies and reduced order. Numerical examples are used to illustrate the theoretical discussion. Even though the results apply in theory to general DAEs, special structures will be exploited for numerically efficient implementations.
arXiv:1804.08755v1 fatcat:icrabu5j4rdoxiiei745i2ebti

Interactive Relationship Discovery via the Semantic Web [chapter]

Philipp Heim, Steffen Lohmann, Timo Stegemann
2010 Lecture Notes in Computer Science  
This paper presents an approach for the interactive discovery of relationships between selected elements via the Semantic Web. It emphasizes the human aspect of relationship discovery by offering sophisticated interaction support. Selected elements are first semi-automatically mapped to unique objects of Semantic Web datasets. These datasets are then crawled for relationships which are presented in detail and overview. Interactive features and visual clues allow for a sophisticated exploration
more » ... f the found relationships. The general process is described and the RelFinder tool as a concrete implementation and proof-of-concept is presented and evaluated in a user study. The application potentials are illustrated by a scenario that uses the RelFinder and DBpedia to assist a business analyst in decision-making. Main contributions compared to previous and related work are data aggregations on several dimensions, a graph visualization that displays and connects relationships also between more than two given objects, and an advanced implementation that is highly configurable and applicable to arbitrary RDF datasets.
doi:10.1007/978-3-642-13486-9_21 fatcat:b3d6zitvvnbilnpq5gc5dzacxi

Sättigende weiche strukturvariable Regelung (Saturated Soft Variable-structure Control)

Michael Buhl, Philipp Joos, Boris Lohmann
2008 at - Automatisierungstechnik  
Der Beitrag beschreibt eine weiche strukturvariable Regelung mit dem Ziel, lineare Strecken mit Stellgrößenbegrenzung nahezu zeitoptimal in eine Ruhelage zu überführen. Dazu werden gezielt Reglerverstärkungen verwendet, die in großen Bereichen des Zustandsraums zu einer Sättigung der Stellgröße führen. Dynamik und Robustheit der Regelung können über zwei Parameter in transparenter Weise eingestellt werden; der numerische Aufwand ist vergleichsweise gering. This paper presents a saturated, soft
more » ... ariable-structure controller. The aim of the controller is a nearly time-optimal transfer of linear systems with input saturation into a desired equilibrium point. For this purpose feedback gains are used which lead in large areas of the state-space to a saturated input signal. The dynamic and the robustness of the controller can be tuned transparently by two parameters; the numercial effort is considered as comparatively low. Schlagwörter: Weiche strukturvariable Regelung, nahezu zeitoptimale Regelung, Stellgrößenbegrenzungen
doi:10.1524/auto.2008.0710 fatcat:ezsk3ptbpfedfdlcosdq2cixsa

RelFinder: Revealing Relationships in RDF Knowledge Bases [chapter]

Philipp Heim, Sebastian Hellmann, Jens Lehmann, Steffen Lohmann, Timo Stegemann
2009 Lecture Notes in Computer Science  
The Semantic Web has recently seen a rise of large knowledge bases (such as DBpedia) that are freely accessible via SPARQL endpoints. The structured representation of the contained information opens up new possibilities in the way it can be accessed and queried. In this paper, we present an approach that extracts a graph covering relationships between two objects of interest. We show an interactive visualization of this graph that supports the systematic analysis of the found relationships by
more » ... oviding highlighting, previewing, and filtering features. 4 5
doi:10.1007/978-3-642-10543-2_21 fatcat:yw2yylsvxvg2ljm4f6ypgfhnsy

Radiomics in radiation oncology—basics, methods, and limitations

Philipp Lohmann, Khaled Bousabarah, Mauritius Hoevels, Harald Treuer
2020 Strahlentherapie und Onkologie (Print)  
Lohmann, K. Bousabarah, M. Hoevels, and H. Treuer declare that they have no competing interests.  ... 
doi:10.1007/s00066-020-01663-3 pmid:32647917 fatcat:nluyxntwzjde7fcdimb7fqmooi

Artificial Intelligence, Radiomics, and Deep Learning in Neuro-Oncology

Norbert Galldiks, Gelareh Zadeh, Philipp Lohmann
2020 Neuro-Oncology Advances  
Recent developments in terms of feature-based PET/MRI radiomics are summarized by Lohmann et al. 6 Several studies demonstrated that the combination of amino acid PET and MRI radiomics encodes more diagnostic  ... 
doi:10.1093/noajnl/vdaa179 pmid:33521635 pmcid:PMC7829469 fatcat:2jlkg734yzf6djafnwprt724de

Semantic Integrator: Semi-Automatically Enhancing Social Semantic Web Environments

Steffen Lohmann, Philipp Heim, Jürgen Ziegler
2007 Conference on Social Semantic Web  
Large amounts of information from various sources have often to be considered when collaboratively developing semantic structures. Examining all relevant information can be very demanding and time consuming. Thus, methods and tools are needed that assist in the integration of this heterogeneous and distributed information. Based on an approach that uses Social Software and Semantic Web technology in requirements engineering, this paper describes the general concept and architecture of the
more » ... ic Integrator, a tool that aims at visually support the integration of distributed information into semantic structures. 1 By Social Semantic Web Environments we mean community platforms that combine Social Software and Semantic Web technologies (e.g. Semantic Wikis).
dblp:conf/cssw/LohmannHZ07 fatcat:jzqycjxdc5ea7ib67kokik3lz4

The RelFinder user interface

Steffen Lohmann, Philipp Heim, Timo Stegemann, Jürgen Ziegler
2010 Proceedings of the 15th international conference on Intelligent user interfaces - IUI '10  
Being aware of the relationships that exist between objects of interest is crucial in many situations. The RelFinder user interface helps to get an overview: Even large amounts of relationships can be visualized, filtered, and analyzed by the user. Common concepts of knowledge representation are exploited in order to support interactive exploration both on the level of global filters and single relationships. The RelFinder is easy-to-use and works on every RDF knowledge base that provides standardized SPARQL access.
doi:10.1145/1719970.1720052 dblp:conf/iui/LohmannHSZ10 fatcat:biluiwarungl3gffgeeivv75i4

Moving Horizon Estimation for Nonlinear Networked Control Systems with Unsynchronized Timescales

Peter Philipp, Boris Lohmann
2011 IFAC Proceedings Volumes  
A moving horizon observer has been designed in Philipp and Lohmann (2009) , capable of dealing with variable time delays and packet drops.  ...  In the following, the approach developed in Philipp (2011b) for computing these sensitivities is extended.  ... 
doi:10.3182/20110828-6-it-1002.02506 fatcat:4oqaarzm6zdbbixovfdm3gjcxm

Exploring Relationships between Annotated Images with the ChainGraph Visualization [chapter]

Steffen Lohmann, Philipp Heim, Lena Tetzlaff, Thomas Ertl, Jürgen Ziegler
2009 Lecture Notes in Computer Science  
., for the tags 'nikon', 'philipp', or 'dcdead'); in others, nodes overlap image parts (e.g., the tags 'green' or 'great').  ... 
doi:10.1007/978-3-642-10543-2_4 fatcat:j4v3rwiobzfjfag3b3e6yyzvty

Current Status of PET Imaging in Neuro-Oncology

Norbert Galldiks, Philipp Lohmann, Nathalie L Albert, Jörg C Tonn, Karl-Josef Langen
2019 Neuro-Oncology Advances  
Over the past decades, a variety of PET tracers have been used for the evaluation of patients with brain tumors. For clinical routine, the most important clinical indications for PET imaging in patients with brain tumors are the identification of neoplastic tissue including the delineation of tumor extent for the further diagnostic and therapeutic management (ie, biopsy, resection, or radiotherapy planning), the assessment of response to a certain anticancer therapy including its (predictive)
more » ... fect on the patients' outcome and the differentiation of treatment-related changes (eg, pseudoprogression and radiation necrosis) from tumor progression at follow-up. To serve medical professionals of all disciplines involved in the diagnosis and care of patients with brain tumors, this review summarizes the value of PET imaging for the latter-mentioned 3 clinically relevant indications in patients with glioma, meningioma, and brain metastases.
doi:10.1093/noajnl/vdz010 pmid:32642650 pmcid:PMC7324052 fatcat:na36o6fkgvgi7lj435hdp4qpde

gFacet: A Browser for the Web of Data

Philipp Heim, Jürgen Ziegler, Steffen Lohmann
2008 International Conference on Semantics and Digital Media Technologies  
This paper introduces a new approach to browsing the Web of data by combining graph-based visualization with faceted filtering techniques. The graph-based visualization of facets supports the integration of different domains and an efficient exploration of highly structured and interrelated datasets. It allows to access information from distant user-defined perspectives and thereby enables the exploration beyond the borders of Web pages.
dblp:conf/samt/HeimZL08 fatcat:cjkpg33jvffethodhztca2yrii

Monoubiquitination of Ancient Ubiquitous Protein 1 Promotes Lipid Droplet Clustering

Daniel Lohmann, Johanna Spandl, Ana Stevanovic, Mario Schoene, Julia Philippou-Massier, Christoph Thiele, Hongyuan Yang
2013 PLoS ONE  
Lipid droplets, the intracellular storage organelles for neutral lipids, exist in a wide range of sizes and of morphologically distinct organization, from loosely dispersed lipid droplets to tightly packed lipid droplet clusters. We show that the lipid droplet protein AUP1 induces cluster formation. A fraction of AUP1 is monoubiquitinated at various lysine residues. This process depends on its internal CUE domain, which is a known ubiquitin-binding domain. AUP1 with a deleted or point
more » ... d CUE domain, as well as a lysine-free mutant, are not ubiquitinated and do not induce lipid droplet clustering. When such ubiquitination deficient mutants are fused to ubiquitin, clustering is restored. AUP1 mutants with defective droplet targeting fail to induce clustering. Also, another lipid droplet protein, NSDHL, with a fused ubiquitin does not induce clustering. The data indicate that monoubiquitinated AUP1 on the lipid droplet surface specifically induces clustering, and suggest a homophilic interaction with a second AUP1 molecule or a heterophilic interaction with another ubiquitin-binding protein.
doi:10.1371/journal.pone.0072453 pmid:24039768 pmcid:PMC3764060 fatcat:araptk4bizbpjjbcktkw5uu5hy
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