Hierarchical skeletal plan refinement : task- and inference structures

This paper presents the task- and inference structure for skeletal plan refinement which was developed for lathe production planning, the application domain of the ARC-TEC project. Two inference structures are discussed: a global inference structure which was developed in the first phase of knowledge acquisition and a more detailed inference structure which builds on the hierarchical organization of the skeletal plans. The described models are evaluated with respect to their cognitive adequacy and their scope of application. The benefits and limitations of the KADS knowledge acquisition methodology are discussed with respect to the development of the two models

Integrated knowledge acquisition from text, previously solved cases, and expert memories

Within the model-based knowledge engineering framework, an integrated knowledge acquisition method was developed for a complex real-world domain with different traces of expertise. By having an expert constructively explain the previously solved cases with more general information from other traces of expertise (text, expert memories) a model-centered knowledge base is constructed. The proposed method allows for an early knowledge verification where the relevance, sufficiency, redundancy, and consistency of knowledge are already assessed at an informal level. The early knowledge verification efficiently prepares the consecutive knowledge formalization. Through a cognitively adequate model of expertise and the explanation-oriented knowledge elicitation procedures, user friendly second generation expert systems may be developed

Using integrated knowledge acquisition to prepare sophisticated expert plans for their re-use in novel situations

Plans which were constructed by human experts and have been repeatedly executed to the complete satisfaction of some customer in a complex real world domain contain very valuable planning knowledge. In order to make this compiled knowledge re-usable for novel situations, a specific integrated knowledge acquisition method has been developed: First, a domain theory is established from documentation materials or texts, which is then used as the foundation for explaining how the plan achieves the planning goal. Secondly, hierarchically structured problem class definitions are obtained from the practitioners\u27 highlevel problem conceptualizations. The descriptions of these problem classes also provide operationality criteria for the various levels in the hierarchy. A skeletal plan is then constructed for each problem class with an explanation-based learning procedure. These skeletal plans consist of a sequence of general plan elements, so that each plan element can be independently refined. The skeletal plan thus accounts for the interactions between the various concrete operations of the plan at a general level. The complexity of the planning problem is thereby factored in a domain-specific way and the compiled knowledge of sophisticated expert plans can be re-used in novel situations

Integrated knowledge acquisition for lathe production planning : a picture gallery

Diese Bildergalerie veranschaulicht den Einsatz der im ARC-TEC Projekt entwickelten integrativen Wissensakquisitionsmethode. Geleitet durch ein Modell der Expertise, wird das Wissen zur Fertigungsplanung für Drehteile aus Texten, Fallsammlungen und Expertenurteilen akquiriert. Drei aufeinander abgestimmte Tools unterstützen die Erhebung, Dokumentation, Überprüfung und Formalisierung des relevanten Wissens.This picture gallery illustrates the application of the integrated knowledge acquisition procedure which was developed in the ARC-TEC project. Guided by a model of expertise, the knowledge for lathe production planning is acquired from texts, previously solved cases, and expert memories. Three coordinated tools support the elicitation, documentation, verification and formalization of the relevant knowledge

ARC-TEC : acquisition, representation and compilation of technical knowledge

A global description of an expert system shell for the domain of mechanical engineering is presented. The ARC-TEC project constitutes an AI approach to realize the CIM idea. Along with conceptual solutions, it provides a continuous sequence of software tools for the acquisition, representation and compilation of technical knowledge. The shell combines the KADS knowledge-acquisition methodology, the KL-ONE representation theory and the WAM compilation technology. For its evaluation a prototypical expert system for production planning is developed. A central part of the system is a knowledge base formalizing the relevant aspects of common sense in mechanical engineering. Thus, ARC-TEC is less general than the CYC project but broader than specific expert systems for planning or diagnosis

Integrated knowledge acquisition for lathe production planning : a picture gallery

Diese Bildergalerie veranschaulicht den Einsatz der im ARC-TEC Projekt entwickelten integrativen Wissensakquisitionsmethode. Geleitet durch ein Modell der Expertise, wird das Wissen zur Fertigungsplanung für Drehteile aus Texten, Fallsammlungen und Expertenurteilen akquiriert. Drei aufeinander abgestimmte Tools unterstützen die Erhebung, Dokumentation, Überprüfung und Formalisierung des relevanten Wissens.This picture gallery illustrates the application of the integrated knowledge acquisition procedure which was developed in the ARC-TEC project. Guided by a model of expertise, the knowledge for lathe production planning is acquired from texts, previously solved cases, and expert memories. Three coordinated tools support the elicitation, documentation, verification and formalization of the relevant knowledge

A reciprocal repression between ZEB1 and members of the miR-200 family promotes EMT and invasion in cancer cells

The embryonic programme ‘epithelial–mesenchymal transition' (EMT) is thought to promote malignant tumour progression. The transcriptional repressor zinc-finger E-box binding homeobox 1 (ZEB1) is a crucial inducer of EMT in various human tumours, and was recently shown to promote invasion and metastasis of tumour cells. Here, we report that ZEB1 directly suppresses transcription of microRNA-200 family members miR-141 and miR-200c, which strongly activate epithelial differentiation in pancreatic, colorectal and breast cancer cells. Notably, the EMT activators transforming growth factor β2 and ZEB1 are the predominant targets downregulated by these microRNAs. These results indicate that ZEB1 triggers an microRNA-mediated feedforward loop that stabilizes EMT and promotes invasion of cancer cells. Alternatively, depending on the environmental trigger, this loop might switch and induce epithelial differentiation, and thus explain the strong intratumorous heterogeneity observed in many human cancers