Compositional synthesis of modular systems

Innovations in Systems and Software Engineering - In contrast to the breakthroughs in reactive synthesis of monolithic systems, distributed synthesis is not yet practical. Compositional approaches...     

Domain object hierarchies inducing multi-level models

Software and Systems Modeling - Conceptual modeling of domain object hierarchies, such as product hierarchies or organization hierarchies, is difficult due to the intricate nature of nonphysical...     

Designing of Copper Nanoparticle Size Formed via Aerosol Pyrolysis

In this article, the synthesis and structural design of spherical, nonagglomerated particles of copper powder, synthesized by ultrasonic atomization of copper sulfate solutions in hydrogen atmosphere at 1173?K (900?°C), was investigated. Well-controlled particle sizes of Cu powders were obtained from precursor solutions of various concentrations. The mean particle diameters and the ranges of particle size distribution were investigated by scanning electron microscopy (SEM). The diameter values of Cu particles obtained experimentally and estimated theoretically, using the most frequently applied atomization models, were compared. Special attention was paid to our break up capillary waves model, described elsewhere and significantly advanced by Jokanovi???s theoretical approach, which was applied for the first time to a copper metal system as described in this article. The best agreement between the calculated and the experimentally obtained values was found using this model.     

Planning in the Real World

In this article, we describe how real world planning problems can be solved by employing Artificial Intelligence planning techniques. We introduce the paradigm of hybrid planning, which is particularly suited for applications where plans are not intended to be automatically executed by systems, but are made for humans. Hybrid planning combines hierarchical planning – the stepwise refinement of complex tasks – with explicit reasoning about causal dependencies between actions, thereby reflecting exactly the kinds of reasoning humans perform when developing plans. We show how plans are generated and how failed plans are repaired in a way that guarantees stability. Our illustrating examples are taken from a domain model for disaster relief missions enforced upon extensive floods. Finally, we present a tool to support the challenging task of constructing planning domain models.     

Unternehmensübergreifender Austausch von sicherheitsrelevantem Wissen

Koordinierte verteilte Angriffe im Internet sind ein akutes Problem. W?hrend Angriffe jedoch in kollaborativen Verbünden organisiert werden, verteidigen Unternehmen sich h?ufig im Alleingang. Sicherheitsma?nahmen gelten oft als wohl gehütete Geheimnisse und werden ungern preisgegeben. In diesem Beitrag werden Methoden und Voraussetzungen vorgestellt, die einen kooperativen Austausch von sicherheitsrelevantem Wissen erm?glichen, ohne damit etwaige eigene Schwachstellen offen zu legen.     

Microstructure, cytotoxicity and corrosion of powder-metallurgical iron alloys for biodegradable bone replacement materials

Up to now biodegradable bone implants with the ability of bearing high loads for the temporary replacement of bones or as osteosynthesis material are not available. Iron and iron based alloys have been identified as appropriate materials, since they combine high strength at medium corrosion rates. Thus, the aim of the present study is the development of a degradable iron based alloy with the perspective of using them as matrix material of cellular structures with biomechanical tailored properties. A powder metallurgical approach has been used to manufacture Fe-C, Fe-0.6P, Fe-1.6P, Fe-B and Fe-Ag samples, which have been tested with respect to their microstructure, their cytotoxicity, and their degradation rate. In order to determine the cytotoxicity of the material a monolayer culture of fibroblast and a perfusion chamber system has been chosen, which was recommended by the ISO 10993-5:1999 for biological testing of medical devices. It has been found, that in particular phosphorus features beneficial properties, since density and thus the strength of the material are increased. No corrosion inhibiting effects of phosphorus on the degradation rate have been found.     

PECVD mit der Bandhohlkathode

Plasma‐enhanced High Rate Surface Treatment of Steel Sheet by Means of the Strip Hollow Cathode Method Low pressure glow discharges are of strong interest for the development of new technologies for steel strip surface treatment for different applications. The challenge of the integration of plasma processes into existing continuous steel sheet coating processes consists in the requirements of a very high deposition rate combined with minimal loss due to parasitic oatings. Regarding these requirements a novel strip hollow cathode process (SHC) for surface treatment based on the hollow cathode effect between two flat and parallel cathodes has been developed. This method has significant potential for surface treatment of large area metal strips in continuous technological processes.     

Analysis of textile-reinforced concrete structures under consideration of non-traditional uncertainty models

This article is a contribution towards the innovative development and practical application of structures reinforced by means of textile fabrics. Textile reinforcement embedded in fine-grained concrete not only finds application in new structures but may also be used for the additional strengthening of existing steel-reinforced concrete (RC) structures.

The article focuses on a FE-model suitable for folded-plate structures. This so-called multi-reference-plane model (MRM) is capable of describing the structural behavior of RC structures strengthened by textile-reinforced concrete (TRC) layers, because those are characterized by a multi-Kirchhoff kinematics. New TRC structures may also be analyzed with the aid of the MRM as structures with one reference plane only.

Experimental and numerical investigations demonstrate that structural responses of TRC structures are highly dependent on the spatial and temporal variation of the uncertain material and geometric data. For this reason the present paper concentrates on the generalized uncertainty modeling of material and geometric parameters with the aid of fuzzy and fuzzy random functions. The uncertainty models and the MRM are combined in the framework of the fuzzy stochastic finite element method (FSFEM). The introduced models are applied to three examples.