The Train Benchmark: cross-technology performance evaluation of continuous model queries

In model-driven development of safety-critical systems (like automotive, avionics or railways), well- formedness of models is repeatedly validated in order to detect design flaws as early as possible. In many indus- trial tools, validation rules are still often implemented by a large amount of imperative model traversal code which makes those rule implementations complicated and hard to maintain. Additionally, as models are rapidly increas- ing in size and complexity, efficient execution of validation rules is challenging for the currently available tools. Checking well-formedness constraints can be captured by declarative queries over graph models, while model update operations can be specified as model transformations. This paper presents a benchmark for systematically assessing the scalability of validating and revalidating well-formedness constraints over large graph models. The benchmark defines well-formedness validation scenarios in the railway domain: a metamodel, an instance model generator and a set of well- formedness constraints captured by queries, fault injection and repair operations (imitating the work of systems engi- neers by model transformations). The benchmark focuses on the performance of query evaluation, i.e. its execution time and memory consumption, with a particular empha- sis on reevaluation. We demonstrate that the benchmark can be adopted to various technologies and query engines, including modeling tools; relational, graph and semantic databases. The Train Benchmark is available as an open- source project with continuous builds from https://github. com/FTSRG/trainbenchmark

Property-Based Methods for Collaborative Model Development

Industrial applications of mo del-driven engineering to de- velop large and complex systems resulted in an increasing demand for collab oration features. However, use cases such as mo del di�erencing and merging have turned out to b e a di�cult challenge, due to (i) the graph- like nature of mo dels, and (ii) the complexity of certain op erations (e.g. hierarchy refactoring) that are common to day. In the pap er, we present a novel search-based automated mo del merge approach where rule-based design space exploration is used to search the space of solution candi- dates that represent con�ict-free merged mo dels. Our metho d also allows engineers to easily incorp orate domain-sp eci�c knowledge into the merge pro cess to provide b etter solutions. The merge pro cess automatically cal- culates multiple merge candidates to b e presented to domain exp erts for �nal selection. Furthermore, we prop ose to adopt a generic synthetic b enchmark to carry out an initial scalability assessment for mo del merge with large mo dels and large change sets

Query-based access control for secure collaborative modeling using bidirectional transformations

Large-scale model-driven system engineering projects are carried out collaboratively. Engineering artifacts stored in model repositories are developed in either offline (checkout-modify-commit) or online (GoogleDoc-style) scenarios. Complex systems frequently integrate models and components developed by different teams, vendors and suppliers. Thus confidentiality and integrity of design artifacts need to be protected by access control policies. We propose a technique for secure collaborative modeling where (1) fine-grained access control for models can be defined by model queries, and (2) such access control policies are strictly enforced by bidirectional model transformations. Each collaborator obtains a filtered local copy of the model containing only those model elements which they are allowed to read; write access control policies are checked on the server upon submitting model changes. We illustrate the approach and carry out an initial scalability assessment using a case study of the MONDO EU project

Deriving Effective Permissions for Modeling Artifacts from Fine-grained Access Control Rules

In case of collaborative modeling, complex systems are de- veloped by different stakeholders. To guarantee security, access control policies need to be enforced during the col- laboration. Levels of required confidentiality and integrity may vary across modeling artifacts, and even features of a single model element. Fine-grained rule-based access control was proposed to meet the needs of flexible and concise access control. Rule- based policies are inherently subject to conflicts between the rules; these conflicts should be interpreted in a consis- tent but also predictable way that caters to the preferences of the policy engineer. We propose a deterministic, parameterizable resolution strategy between conflicting rules to calculate effective ac- cess permissions for each fact in the model. Our approach is illustrated using a case study of the MONDO EU projec

Visualization of Traceability Models with Domain-specific Layouting

Traceability models are often used to describe the correspondence between source and target models of model transformations. Although the visual representation of such models are important for transformation development and application, mostly ad-hoc solutions are present in industrial environments. In this paper we present a user interface component for visualizing traceability models inside transformation frameworks. As generic graph visualization methods fail to emphasize the underlying logical structure of our model, we used domain-specific layouts by customizing generic graph layout algorithms with data from the metamodels used during the transformation. This approach was evaluated, among others, with the traceability models generated by a BPEL verification transformation, which serves as our running example

The treatment of gastric tumours in our practice: A five year survey

Between the 1 It of January, 1998 and the 3111 of December, 2002 we treated Ill patients for gastric cancer in the 2nd Department of Surgery, Semmelweis University, Budapest, Hungary. The majority of patients belonged to the advanced stages of the disease. In 65% of the cases a partial or total gastrectomy was performed. We combined the operation with D2 lymphnode dissection if a R0 resection was possible, in the other cases with D1 lymphadenectomy. Postoperative morbidity rate ranged to 15%, the mortality 5.4%. 74patients could be followed, 41 are dead and 33 still alive. According to the follow up examination the median survival time is 20.4 months at the moment. We observed a significantly shorter survival time, if vascular or lymphoid vessel invasion was present in the histologic specimen. The study has not been finished and the follow up will be continued