Ludger Jansen

Dr. Ludger Jansen

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Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2019 in Aging and disease
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Journal Article
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GFGeorg Fuellen
Georg Fuellen
LJLudger Jansen
Ludger Jansen
ACAlan A Cohen
Alan A Cohen
WLWalter Luyten
Walter Luyten
MGManfred Gogol
Manfred Gogol
SMSteffen Möller
Steffen Möller
Despite increasing research efforts, there is a lack of consensus on defining aging or health. To understand the underlying processes, and to foster the development of targeted interventions towards increasing one's health, there is an urgent need to find a broadly acceptable and useful definition of health, based on a list of (molecular) features; to operationalize features of health so that it can be measured; to identify predictive biomarkers and (molecular) pathways of health; and to suggest interventions, such as nutrition and exercise, targeted at putative causal pathways and processes. Based on a survey of the literature, we propose to define health as a state of an individual characterized by the core features of physiological, cognitive, physical and reproductive function, and a lack of disease. We further define aging as the aggregate of all processes in an individual that reduce its wellbeing, that is, its health or survival or both. We define biomarkers of health by their attribute of predicting future health better than chronological age. We define healthspan pathways as molecular features of health that relate to each other by belonging to the same molecular pathway. Our conceptual framework may integrate diverse operationalizations of health and guide precision prevention efforts.

20 March 2007 in Topoi
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LJLudger Jansen
Ludger Jansen
We live in the age of computerised information. Several thousand millions of web sites are accessible online in the World Wide Web. Some supermarket chains collect terabytes of customer information. Hospitals struggle to document their work in Electronic Health Records (Ball and Collen 1992). Even some branches of science, like Genetics, are no longer possible without computerised storage and retrieval of information, so huge is the collection of data that is amassed by scientists in these fields. A hundred years ago, it was still possible for a medical practitioner to keep track with the progress of this profession. Today, a practitioner would need several weeks of reading to cope with a day’s output of medical research (Gaus 2003). But how can a medical practitioner find the relevant information when he needs it? How do we find the relevant pages in the ocean of the World Wide Web, or entries in databases? We need reliable techniques of information retrieval: search engines, indices,

22 August 2014 in PLOS ONE
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ADAstrid Duque-Ramos
Astrid Duque-Ramos
MBMartin Boeker
Martin Boeker
LJLudger Jansen
Ludger Jansen
SSStefan Schulz
Stefan Schulz
MIMiguela Iniesta
Miguela Iniesta
Jesualdo Tomás Fernández-BreisJesualdo Tomás Fernández-Breis
Jesualdo Tomás Fernández-Breis
To (1) evaluate the GoodOD guideline for ontology development by applying the OQuaRE evaluation method and metrics to the ontology artefacts that were produced by students in a randomized controlled trial, and (2) informally compare the OQuaRE evaluation method with gold standard and competency questions based evaluation methods, respectively. In the last decades many methods for ontology construction and ontology evaluation have been proposed. However, none of them has become a standard and there is no empirical evidence of comparative evaluation of such methods. This paper brings together GoodOD and OQuaRE. GoodOD is a guideline for developing robust ontologies. It was previously evaluated in a randomized controlled trial employing metrics based on gold standard ontologies and competency questions as outcome parameters. OQuaRE is a method for ontology quality evaluation which adapts the SQuaRE standard for software product quality to ontologies and has been successfully used for evaluating the quality of ontologies. In this paper, we evaluate the effect of training in ontology construction based on the GoodOD guideline within the OQuaRE quality evaluation framework and compare the results with those obtained for the previous studies based on the same data. Our results show a significant effect of the GoodOD training over developed ontologies by topics: (a) a highly significant effect was detected in three topics from the analysis of the ontologies of untrained and trained students; (b) both positive and negative training effects with respect to the gold standard were found for five topics. The GoodOD guideline had a significant effect over the quality of the ontologies developed. Our results show that GoodOD ontologies can be effectively evaluated using OQuaRE and that OQuaRE is able to provide additional useful information about the quality of the GoodOD ontologies.

1 January 2011 in Journal of Biomedical Semantics
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Journal Article
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JRJohannes Röhl
Johannes Röhl
LJLudger Jansen
Ludger Jansen
Dispositions and tendencies feature significantly in the biomedical domain and therefore in representations of knowledge of that domain. They are not only important for specific applications like an infectious disease ontology, but also as part of a general strategy for modelling knowledge about molecular interactions. But the task of representing dispositions in some formal ontological systems is fraught with several problems, which are partly due to the fact that Description Logics can only deal well with binary relations. The paper will discuss some of the results of the philosophical debate about dispositions, in order to see whether the formal relations needed to represent dispositions can be broken down to binary relations. Finally, we will discuss problems arising from the possibility of the absence of realizations, of multi-track or multi-trigger dispositions and offer suggestions on how to deal with them.

1 January 2007 in The Monist
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Journal Article
Closed access
LJLudger Jansen
Ludger Jansen
TIThe Hegeler Institute
The Hegeler Institute

1 January 2013
Verified
Journal Article
Closed access
SSStefan Schulz
Stefan Schulz
LJLudger Jansen
Ludger Jansen