One way of describing the material behaviour of welded components is the implementation of weld strength factors in the design process or life assessments. In general, this factor neither takes the influence of the complex, multiaxial stress situation in large components into account, nor relaxation or constraint effects. In the research presented here, numerical finite element simulations using inelastic constitutive equations – offering the possibility to characterise the influence of the stress distribution and degree of multiaxiality in the weld region – are used to obtain a more detailed interpretation of reduced weld strength. Different weld geometries are investigated by finite element analysis with regard to evaluate the influence of the weld on the overall component behaviour. The results show, that the transferability of small scale material properties and in particular the weld strength factor to thick walled parts based on analytical methods is difficult and may not be an appropriate tool for the design of welded components.
Software agents are intended to perform certain tasks on behalf of their users. In many cases, however, the agent’s competence is not sufficient to produce the desired outcome. This paper presents an approach to cooperative problem solving in which a software agent and its user try to support each other in the achievement of a particular goal. As a side effect the user can extend the agent’s capabilities in a programming-by-demonstration dialog, thus enabling it to autonomously perform similar tasks in the future.
Software agents are intended to autonomously perform certain tasks on behalf of their users. In many cases, however, the agent's competence might not be sufficient to produce the desired outcome. Instead of simply giving up and leaving the whole task to the user, a much better alternative is to precisely identify what the cause of the current problem is, communicate it to another agent who can be expected to be able (and willing) to help, and use the results to carry on with achieving the original goal. An ideal candidate for the role of such a supporting agent is the user of a system who can certainly be expected to have some interest in obtaining a useful response, even at the cost of having to intervene from time to time. As a consequence it seems rational to ask her for help whenever the system gets into trouble. The paradigm of programming by demonstration (pbd) provides a feasible framework for the particular kind of dialog required in such situations in which both user and agent use their individual capabilities not only to complement each other in order to overcome the current problem; instead the objective is to extend the agent's skills, thus enabling him to successfully deal with a whole class of problems and avoiding similar difficulties— and thus, additional training effort—for the future. As a concrete application scenario imagine a Web-based travel agent that makes use of dynamic information located at various Web sites in order to configure a trip satisfying the user's preferences and constraints. Typical information sources to be used in such a case include the Web sites of airlines, hotels, possibly weather servers and so on. Unfortunately, many of these Web sites tend to change their look and structure quite frequently, thus exasperating agents that are not flexible enough to deal with this unexpected situation or at least recognize the fact that there exists a problem at all. Wouldn' t it be good if this agent could tell e.g. his user
