Directions in AI Research and Applications at Siemens Corporate

AI Magazine Volume 11 Number 1 (1991)(1990) (© AAAI) Research in Progress

of linguistic phenomena. The com- Directions in AI Research putational work concerns questions of adequate processing models and algorithms, as embodied in the and Applications at actual interfaces being developed. These topics are explored in the Siemens Corporate Research framework of three projects: The natural language consulting dialogue and Development project (Wisber) takes up research- oriented topics (descriptive grammar formalisms and linguistically adequate grammar specification, handling of Wolfram Buettner, Klaus Estenfeld, discourse, and so on), the data-access Hans Haugeneder, and Peter Struss project (Sepp) focuses on the practical application of state-of-the-art technology, and the work on grammar-development environments ■ Many barriers exist today that prevent particular, Prolog extensions; and (4) (Ape) centers on the problem of ade- effective industrial exploitation of current design and analysis of neural networks. quate tools for specifying linguistic and future AI research. These barriers can The lab’s 26 researchers are orga- knowledge sources and efficient pro- only be removed by people who are work- nized into four groups corresponding cessing methods. ing at the scientific forefront in AI and to these areas. Together, they provide Wisber is jointly funded by the know potential industrial needs. Siemens with innovative software The Knowledge Processing Laboratory’s German government and several research and development concentrates in technologies, appropriate applications, industrial and academic partners. the following areas: (1) natural language prototypical implementations of AI The goal of the project is to develop interfaces to knowledge-based systems and systems, and evaluations of new a knowledge-based advice-giving databases; (2) theoretical and experimen- techniques and trends. system in the domain of financial tal work on qualitative modeling and In addition to its responsibilities to consultation. nonmonotonic reasoning for future knowl- the company, the lab aims at estab- edge-based systems; (3) application-specif- lishing close contacts with the out- The group's ic language design, in particular, Prolog side scientific community. In part, extensions; and (4) design and analysis of this contact is made by sharing tech- general strategy neural networks. nical results and advances in AI This article gives the reader an overview for validating its of the main topics currently being pursued technology and its theoretical foun- theoretical work is in each of these areas. dations. Furthermore, lab researchers support a two-way exchange of infor- to build prototypi- mation through publications and Many barriers exist today that pre- talks on current work as well as activ- cal tools and vent effective industrial exploitation ities as referees, teachers at tutorials, integrate them of current and future AI research. and conference organizers. into a system. These barriers can only be removed The remainder of this article gives by people who are working at the the reader an overview of the main scientific forefront in AI and know topics currently being pursued in The natural language analysis com- potential industrial needs. each of the four groups. ponent is the laboratory’s responsi- The Knowledge Processing Lab- bility. It is based on a lexical-func- oratory within Siemens Corporate Natural Language tional grammar (LFG)–type parser Research and Development in Technology (Block and Hunze 1986; Block and Munich, Germany, aims at breaking Haugeneder 1988) but handles long- down these barriers. With over Current state-of-the-art natural lan- distance phenomena more in the 350,000 employees and a product guage interfaces have many limita- spirit of the slash categories of the line ranging from coffee makers to tions. Among these are a linguistic generalized phrase structure gram- mainframe computers, Siemens is coverage that is too narrow, restricted mar. It uses discourse representation one of the world’s leading high-tech types of dialogue interaction, insuffi- theory (DRT) as the framework for its companies. Its interest in leading- cient robustness, and modeling of semantic and discourse representa- edge technologies such as AI is the application domain that is too tion (Hunze 1988; Frederking and understandable. implicit. Gehrke 1988). A KL-TWO–type repre- The Knowledge Processing Labora- To develop interfaces that do not sentation formalism is used for con- tory’s research and development con- exhibit these limitations, the Natural ceptual modeling. A grammar centrates in the following areas: (1) Language Technology Group is compiler developed by the laboratory natural language interfaces to knowl- engaged in basic research and in the allows grammars to be perspicuously edge-based systems and databases; (2) development of actual applications. written but efficiently processed. theoretical and experimental work The theoretical work encompasses Because morphology is of critical on qualitative modeling and non- such elements as the development of importance in German, we also monotonic reasoning for future expressive formal representations for developed a morphological analyzer knowledge-based systems; (3) appli- linguistic knowledge and empirically using the same formalism as for syn- cation-specific language design, in tested, formally explicit descriptions tactic analysis. Additionally, we

implemented a component for han- facilities. The next version of this control strategies (Haugeneder and dling and accessing large lexicons on interface will employ left-corner Gehrke 1987) using an agenda con- the basis of discrimination trees and parsing, making use of bottom-up trol mechanism. These capabilities random-access methods (Gehrke and information in addition to the top- have been used extensively in the Block 1986). A sizable, restrictively down information already used. development of heuristic search formulated German grammar is Work also continues on extending strategies that are independent of the being developed as part of this work Sepp’s linguistic coverage, especially underlying grammar formalism (Hau- using government and binding con- with regard to quantifiers, ellipses, geneder and Gehrke 1988). Ape is cepts within an LFG representation and comparative constructions (the implemented in Interlisp-D on a (Schachtl 1988). These components latter are currently handled by semi- Siemens 58xx. run in Interlisp-D on a Siemens 58xx formal expressive features). Enlarging To provide a focus for future work, (Xerox 1100) workstation. the functionality and user friendli- we have adopted the ambitious goal Sepp (SESAM preprocessor) is a ness of Sepp’s domain-tailoring tools of developing a linguistic core pro- natural language interface to database will also be tackled (Schmid 1988). cessor (LCP) that will bring together systems supporting the standard The development of the system is the results of the work in the three query language SQL (Block and being performed in Prolog on SUN preceding projects. LCP will be an Schlereth 1987). Included are tools workstations, with Siemens MX integrated, application-neutral natu- for adjusting the domain-indepen- (Unix-based) computers as target ral language–processing component dent language processor to a specific machines. having linguistic capabilities ade- database. Sepp functions as a transla- The Ape (augmented transition quate for a variety of interface uses. tor, producing SQL queries in a two- network [ATN] programming envi- LCP is envisioned not only as being phase process. Natural language ronment) grammar-development parameterized with respect to domain queries are mapped into SQL queries environment is a highly interactive but also as being usable as a natural through an intermediate abstract, development and testing environ- language interaction component in object-centered internal representation. ment for the ATN formalism based multimodal user interfaces. The natu- The current version of Sepp is being on an active chart parser (Haugened- ral language facilities of LCP will used in a pilot project by an organi- er and Gehrke 1986). This system include the analysis of natural lan- zation outside Siemens to access allows the specification and debug- guage input as well as the generation information in its large, real-world ging of network-style grammars of natural language output. In its database. This experience will give us using an extensive graphic interface final version, it will have comprehen- feedback on the system’s language and provides a highly flexible tool sive coverage and be robust in the coverage, habitability, and overall for defining and testing various face of ungrammatical input, attentive

SPRING 1990 21 Research in Progress to its discourse context, and alert to As implemented, this framework the implications of a variety of speech The statement of deals with hierarchical models and acts. Of course, the initial version a problem should allows focusing within these models will be significantly limited compared at the same time (Struss 1988a, 1988b), handles to the eventual LCP, with develop- dynamic device models (Dressler and ment proceeding incrementally. be an executable Freitag 1989), and integrates fault Participants: H. Haugeneder, H. U. computer program models exploiting the extended Block, R. Frederking (until June 1989), ATMS (Struss and Dressler 1989). M. Gehrke, R. Hunze, S. Schachtl, that solves the Future work involves investigating and L. Schmid. problem. and exploiting the relationships between qualitative reasoning and nonmonotonic reasoning, for exam- Advanced Reasoning ple, a description of process models Methods using situation-action structures. The for implementing systems based on work will emphasize the dynamic The Advanced Reasoning Methods ATMSs or JTMSs. Controlling the aspects of the application domains, Group is engaged in the areas of inferences of TMS-based problem for example, by considering actions qualitative reasoning and truth solvers is a central problem of the taken by a diagnostician that shift maintenance. Both are key issues in field. The control strategy for ATMS, the device under consideration into building systems that use deep knowl- which is based on local control different states. Paradigms from both edge as opposed to the conventional guards and a global focus (Dressler qualitative and nonmonotonic rea- rules of thumb extracted from domain and Farquhar 1989), enables the soning must be integrated. experts. The group participates in the implementation of tight problem Participants: P. Struss, R. Decker (until TEX-B project, Foundations for solver control. It is general enough to June 1989), O. Dressler, H. Freitag, M. Expert Systems in Technical Domains, represent all control regimes that Reinfrank, and A. Farquhar (guest which is funded by the German have been proposed for ATMS in the researcher until July 1989). government. literature. The results obtained to date in the Based on these TMSs, the group area of qualitative reasoning systems has developed constraint systems, in Prolog Extensions for include a framework for component- particular, for the propagation of Scientific and Technical oriented device modeling with a temporally indexed values (Decker Applications means for structuring models in a 1988; Dressler and Freitag 1989). hierarchical and view-oriented fash- A recent and noteworthy theoreti- The ideal of declarative programming ion and focusing the analysis of these cal contribution of the group is a log- can be summarized as follows: The models (Struss 1987). A systematic ical theory of truth maintenance statement of a problem should at the analysis of contemporary qualitative (Reinfrank and Dressler 1989). By same time be an executable comput- reasoning methods within a general translating JTMSs, as well as ATMSs, er program that solves the problem. mathematical model of qualitative into a variant of nonmonotonic This ideal has been approximated by calculi (based on algebraic and differ- logic, the theory puts truth mainte- Prolog, but there has been little evi- ential equations) uncovered some nance on a firmer ground than was dence that Prolog could achieve the inherent limitations to these approach- previously possible. ideal in a technical industrial envi- es (Struss 1988c, 1988d, 1988e). Con- The group’s general strategy for ronment, for example, very large- tinued joint work in this area with validating its theoretical work is to scale integrated circuit design, researchers from XEROX Palo Alto build prototypical tools and integrate communications systems, or knowl- Research Center led to the thesis that them into a system. This practical edge-based design of technical systems. some of these limitations can be system functions as a workbench, The Language Extension Group has overcome by radically departing from providing a basis for experimentation tried to meet the need for declarative the concepts of differential calculus and empirical feedback into further programming in these areas by suit- and focusing on commonsense theoretical investigations. ably extending Prolog. On the basis physics (Huberman and Struss 1989). The practical application of the of theoretical research (Buettner In the area of truth maintenance, group’s techniques in this case is 1988; Enders 1989), a new system, the group’s main contributions are model-based diagnosis (Struss 1988a, PROLOG-XT (Estenfeld and Ruckert extensions to justification-based 1988b, 1989a, 1989b). Currently, the 1988), was designed and implemented. truth maintenance systems (JTMSs) diagnostic system under development Most current commercial Prolog and assumption-based truth mainte- is mainly evaluated in the domain of systems lack expressiveness, efficient nance systems (ATMSs). These efforts thyristor circuits for the power supply control, and ease of use. Many com- include integrating nonmonotonic and control of direct-current motors. plex application domains cannot be justifications into the essentially This example confronts approaches adequately modeled. Unification monotonic ATMS as well as encoding to model-based diagnosis with sever- only works on a syntactic level (Her- disjunctive and negative information al important challenges, such as brand terms); there is no possibility (Dressler 1988a, 1988b). Justification feedback, the changing of device to reflect, for example, the algebraic schemata (Freitag and Reinfrank topology, temporal reasoning, impre- properties of special application 1988; Reinfrank and Freitag 1988) cise observations, and multiple domains. Representing hierarchically add limited first-order capabilities to models. The approach is based on an structured knowledge for knowledge- the inherently propositional TMSs extended version of de Kleer and based systems is possible only on top and constitute an alternative choice Williams’s general diagnostic engine. of Prolog. Inheritance mechanisms

22 AI MAGAZINE Research in Progress

Figure 1. Modeling of Input-Output Relations in a Digital Circuit Using Prolog-XT. implicitly available in object-oriented PROLOG-XT on the basis of a delay managed. Method selection and programming languages have to be mechanism. Delay conditions that inheritance are automatically regulat- explicitly coded. are checked at run time and might ed by sorted variables in the clause As a control mechanism, only the possibly delay the execution of a goal heads. To achieve high performance, Prolog standard computation rule is can be added to any user-defined abstract machine instructions are available; no clean mechanisms are at Prolog procedure. In most cases, it is added that handle sorted variables hand to avoid superfluous computa- the noninstantiation of goal parame- and indexing over classes. tion steps. Comfortable program- ters at run time that is responsible for Based on the object system, a ming environments and graphic tools the delay. The idea is to postpone the microshell for rapid prototyping of for building application-specific user execution of such a goal until its expert systems was built. The effi- interfaces are the exception. The parameters are sufficiently instantiated. ciency of the compiler integrated facilities for closely coupling Prolog Unnecessary computation steps can approach was proved in an expert programs with more conventional thereby be avoided. system project (Ruckert and Voges software are usually only rudimentary. With PROLOG-XT, application- 1989). The new Prolog system PROLOG-XT related user interfaces can be easily The Prolog kernel of PROLOG-XT is intended to cope with these defi- constructed. A set of integrated built- is based on the compiler system ciencies. The expressiveness of stan- in predicates provides full access to SEPIA V2.0 (Meier 1988) of ECRC dard Prolog is extended in several standard graphics and window man- (European Computer Industry ways. Domain-specific semantics can agement tools. A graphic debugger Research Centre). The extensions be modeled through algebraic terms, for the objects allows comfortable concerning finite algebras, graphic and unification is extended to finite program development. External lan- interface, and definite-clause gram- algebraic models. Thus, for example, guage code can easily be accessed mars were designed and implement- the input-output relations of digital through the C language interface. ed at Siemens; the extensions circuits on the gate level can be mod- Backtrackable and even delayable C concerning object-oriented program- eled by Boolean functions and pro- functions can be written and handled ming are based on an implementa- cessed in PROLOG-XT by Boolean this way. tion of ECRC. It was extended at unification (figure 1). The object system of PROLOG-XT Siemens with a browser and an exter- Object-oriented programming is (Enders 1989) is based on order- nal representation formalism. integrated into PROLOG-XT through sorted logic. Classes (the object-ori- PROLOG-XT runs on the Siemens typed variables and typed unification ented analogy to sorts), metaclasses, workstation WS 30-4xx (Apollo DN on a compiler level. Hierarchically and objects are provided. Reasoning 4000) under Unix System V. Figure 1, structured knowledge can thus be on the class hierarchy (multiple from the domain of circuit design, represented in a natural way and pro- inheritance) is enabled through shows how a full adder is specified cessed efficiently. sorted variables. Procedures are gen- and verified in PROLOG-XT. To overcome the standard (static) eralized to generic procedures, such A circuit verification environment computation rule and to keep it flexi- that methods (procedure parts belong- (CVE), based mainly on the extended ble, coroutining is incorporated into ing to a class) can be independently (continued on page 26)

SPRING 1990 23 Research in Progress . . . artificial some of the basic characteristics of defining a Hopfield net or a Boltz- human perception, such as massive mann machine, that solve the task. It neural networks parallelism, adaptivity, and robust- is the massive parallelism that neural . . . were intro- ness. These properties happen to cor- nets focus on such problems that respond to principal weaknesses in appears promising and deserves duced as highly conventional information process- attention within the project. connected ing. Therefore, the recently reactivat- In the most difficult case, the struc- ed field of neurocomputing has ture of a problem is entirely hidden networks of drawn enormous scientific and com- in the data, and the learning must elementary pro- mercial attention to its activities. reveal this structure and synthesize a Neurocomputing is expected to aug- net. As an example of this type of cessing elements. ment conventional computing with problem, we are currently experi- an important new paradigm. menting with time series derived To obtain reliable statements about from biosignals and economic data. the medium-term potential of ANNs Under certain application-specific unification and the graphic package for information technology, Siemens hypotheses, the results obtained to of PROLOG-XT, was built. With this decided to launch a three-year Neu- date are encouraging. tool, real circuits are symbolically ver- rodemonstrator Project (Buettner et However, both theory and practice ified on gate and switch level. For al. 1989) to integrate and extend pre- confirm that unrestricted learning is example, a 16-bit full adder (900 vious activities in neural nets. The costly. To remove part of the burden switches) was verified within 12 project started in October 1988; the from the learning routine, explicitly seconds. total effort involved will be approxi- known information about the struc- For the first time ever (as far as we mately 60 person-years. ture of the problem should be used are aware), a complete 64-bit ALU The project goal is a system that to construct the coarse structure of (11000 transitors) was symbolically combines conventional and neural the network. One problem of this verified. A translator was developed approaches to industrial scene analy- type is visual pattern recognition as part of CVE. It maps the internal sis. Methods, principles, and proce- subject to certain invariance proper- circuit descriptions of different CAD dures for the design and analysis of ties such as rotation. Such invari- systems into PROLOG-XT programs, ANNs are to be studied and devel- ances induce relations between net thus providing an interface to con- oped under the real-world constraints parameters, thereby reducing the ventional design systems. of the application. Application-spe- number of free parameters. Two other applications in the cific requirements must be translated We are currently incorporating domain of digital circuit design are into network characteristics. On the such knowledge into the learning handled by the extended unification: software side, a software develop- routines of various models. It is in the generation of test patterns and ment environment comprising a this spirit that we expect to perhaps synthesis problems (Tiden 1988). CVE compiler for a programming lan- bridge the gap between the symbolic is in use in a design center within guage for ANNs and a comfortable and the connectionist approaches Siemens for application-specific inte- user interface will be provided. For to AI. grated circuits (ASICs). Substituting fast emulation of neural nets, a co- We are also exploring another formal verification for lengthy testing processor board will be developed. approach to solving invariant pat- and simulation reduces development The Neurodemonstrator Project is tern-recognition problems in which a time and improves reliability. This accompanied by research on the vector of geometric features is substitution is of high importance for technological aspects of ANNs. The extracted from a pattern by a prepro- cost-effective circuit development. Knowledge Processing Laboratory is cessor and then fed to a neural net The results obtained to date with CVE an important part of this project. The for recognition. are promising (Tiden 1989). lab’s primary effort is in the area of The prominent feature of the Hop- We have started using PROLOG-XT design and analysis of neural net- field net is the existence of a cost to tackle tasks that occur in the works. function (determined by weights and design of communication systems. The design of a neural net requires thresholds) on the state space of the As a first project, a specification and transforming the structure of a prob- net. Alterations (such as weight verification environment for commu- lem into the topological-functional changes) in the state of the net nication protocols was developed. structure of a net, which solves the should only come about in a cost- Participants: W. Buettner, K. Estenfeld, problem in a highly parallel fashion. reducing manner. Stability, in partic- R. Enders, H. Leiss, M. Ruckert (until This mapping is achieved by fixing a ular, is ensured this way. June 1989), R. Schmid, H.-A. Schnei- connectivity structure; defining A basic requirement in the Hop- der, D. Taubner, and E. Tiden. input-output nodes; and choosing field net, as well as in the other net parameters such as weights, dynamically stable networks reported Design and Analysis of thresholds, activation functions, and to date in the literature, is that the Neural Networks time scales. connection matrix be symmetric. We In the simplest case, you explicitly have been able to show that stability Inspired by the functioning of human extract the topology and parameters is preserved under general conditions. (or biological) nervous system percep- for a suitable net from the problem. Initial results indicate that our gener- tion, artificial neural networks Various optimization problems, such alization is more efficient for pattern (ANNs) were introduced as highly as the traveling salesman or associa- association than continuous Hop- connected networks of elementary tive access, can be coded into field, Cohen-Grossberg, and Kosko processing elements. They exhibit quadratic (or higher-order) forms, models (Schuermann 1989).

26 AI MAGAZINE Workshops

An important goal of network the Ninth International Conference on design is the development of a Automated Deduction. Argonne. methodology that allows nets to be Buettner, W.; Estenfeld, K.; Schmid, R.; hierarchically specified and composed Schneider, H.-A.; and Tiden, E. 1988. A from subsets, as in circuit design. For General Framework for Symbolic Con- simple binary nets, we experiment straint Handling in Prolog, Technical with PROLOG-XT as an executable Report, INF2-ASE-1-88, Siemens AG. net specification language. Buettner, W., and Simonis, H. 1987. We are also developing a network Embedding Boolean Expressions into simulator in the form of a C library Logic Programming. In Journal of Symbolic containing a variety of neural net- Computation 4:191–205. work algorithms and models; a pilot Decker, R. 1988. Modeling the Temporal version of the simulator is available. Behavior of Technical Systems. In Pro- Further work will go into the devel- ceedings of the Twelfth German Work- shop on Artificial Intelligence, opment of a C-based programming Informatik-Fachberichte. Berlin: Springer. language for neural nets. A compiler will be available in September 1990. Dressler, O. 1988a. Extending the Basic ATMS. In Proceedings of the Eighth Euro- In a later stage of the project, we pean Conference on Artificial Intelli- will need techniques for observing gence. London: Pitman. network dynamics, which go beyond Dressler, O. 1988b. An Extended Basic panning and zooming. It might be ATMS. In Proceedings of the Second necessary to abandon the microscop- Internal Workshop on Nonmonotonic ic picture of individual nodes and Reasoning. Berlin: Springer. weights and switch to macroscopic Dressler, O., and Farquhar, A. 1989. Prob- descriptions of the network’s behav- lem Solver Control over the ATMS. In ior, for example, by calculating Proceedings of the Thirteenth German moments of distribution functions Workshop on Artificial Intelligence, Infor- for the nodes and weights. matik-Fachberichte. Berlin: Springer. Also Participants: W. Buettner, F. Hergert, 1989. Technical Report, INF2-ARM-13-89, M. Hoehfeld, I. Leuthaeusser, B. Siemens AG. Schuermann, M. Weick, P. Witschel, Dressler, O., and Freitag, H. 1989. Propa- and H. G. Zimmermann. gation of Temporally Indexed Values in Multiple Contexts. In Proceedings of the Thirteenth German Workshop on Artifi- Bibliography cial Intelligence, Informatik-Fachberichte. Block, H. U., and Haugeneder, H. 1988. Berlin: Springer. An Efficiency-Oriented LFG-Parser. In Enders, R. 1989. The Object-Oriented Natural Language Parsing and Linguistic Extension of PROLOG-XT, Technical Theory, eds. U. Reyle and C. Rohrer. Dor- Report, INF2-ASE-7-89, Siemens AG. drecht. Estenfeld, K., and Ruckert, M. 1988. Block, H. U., and Haugeneder, H. 1986. Knowledge Processing with PROLOG-XT. The Treatment of Movement-Rules in a In Proceedings of Artificial Intelligence in LFG-Parser. In Proceedings of the Practice. Munich: Siemens AG. Eleventh International Conference of Farquhar, A. 1989. Modifying the Model Computational Linguistics (COLING-86). Sets during Diagnosis. In Proceedings of Bonn. the Thirteenth German Workshop on Block, H. U., and Hunze, R. 1986. Incre- Artificial Intelligence, Informatik-Fach- mental Construction of C- and F-Structure berichte. Berlin: Springer. in a LFG-Parser. In Proceedings of the Farquhar, A. 1988. A Qualitative Reason- Eleventh International Conference of ing Approach to Fault Avoidance. In Pro- Computational Linguistics (COLING-86). ceedings of the Eighth European Bonn. Conference on Artificial Intelligence. Block, H. U., and Schlereth, D. 1987. Nat- London: Pitman. ural Language Access to SESAM. In Pro- Frederking, R. E., and Gehrke, M. 1988. ceedings of the Siemens User’s Resolving Anaphoric References in a DRT- Association. Heidelberg. Based Dialogue System. In Proceedings of Buettner, W. 1989. Implementing Com- the Fourth Austrian Conference on Artifi- plex Domains of Application in an cial Intelligence, Vienna Workshop on Extended Prolog System. In International Knowledge-Based Natural Language Pro- Journal of General Systems 15:129–139. cessing, Informatik-Fachberichte. Berlin: Buettner, W., et. al. 1989. Artificial Neural Springer. Networks in Microelectronics. In Micro- Freitag, H., and Reinfrank, M. 1988. A electronics for Artificial Neural Nets, eds. H. Non-Monotonic Deduction System Based Klar and U. Ramacher. Duesseldorf, Ger- on (A)TMS. In Proceedings of the Eighth many: VDI. European Conference on Artificial Intelli- Buettner, W. 1988. Unification in Finite gence. London: Pitman. Algebras Is Unitary(?). In Proceedings of Gehrke, M., and Block, H. U. 1986. Mor-

SPRING 1990 27 Research in Progress pheme-Based Lexical Analysis. In Proceed- tive Bidirectional Associative Memory. In ings of the Second Annual Conference of Proceedings of the International Neural Klaus Estenfeld is leader of the Language the University of Waterloo Centre for the Network Conference. San Diego. Extension Group at Siemens Corporate New Oxford English Dictionary, Advances Struss, P. 1989a. Diagnosis as a Process. In Research and Development, with special in Lexicology. Waterloo. Proceedings of the 1989 Workshop on interests in Prolog implementation and Haugeneder, H., and Gehrke, M. 1988. Model-Based Diagnosis. Paris: IBM. the extension of Prolog for special applications (for example, computer-aided Improving Search Strategies: An Experi- Struss, P. 1989b. Model-Based Reasoning, design electronics, XPS). He received his ment in Best-First Parsing. In Proceedings Progress, and Problems. In Proceedings of diploma in 1976 and his Ph.D. in 1980, of the Twelfth International Conference the 1989 Congress of the German Nation- both in computer science from the Uni- of Computational Linguistics (COLING- al Computer Science Association (GI versity of Saarbrucken. In 1981, he joined 88). Budapest. Congress) on Knowledge-Based Systems. the Siemens Research Labs, working in Haugeneder, H., and Gehrke, M. 1987. Berlin: Springer. the field of program construction and ver- Modeling Heuristic Parsing Strategies. In Struss, P. 1988a. A Framework for Model- ification, with special interests in parsing Proceedings of the Eleventh German Based Diagnosis, Technical Report, INF2- and unification. From 1984 to 1986, he Workshop on Artificial Intelligence, Infor- ARM-10-88, Siemens AG. was project leader in the Logic Program- matik-Fachberichte. Berlin: Springer. Struss, P. 1988b. Extensions to ATMS- ming Group of the European Computer- Haugeneder, H., and Gehrke, M. 1986. A Based Diagnosis. In Artificial Intelligence in Industry Research Center (ECRC), where User-Friendly ATN Programming Environ- Engineering: Diagnosis and Learning, ed. J. he was responsible for the ECRC Prolog ment (APE). In Proceedings of the Gero, 3–28. Southampton, England: Com- Project. Eleventh International Conference of putational Mechanics. Computational Linguistics (COLING-86). Bonn. Struss, P. 1988c. Global Filters for Qualita- tive Behaviors. In Proceedings of the Sev- Huberman, B., and Struss, P. 1989. Chaos, enth National Conference on Artificial Hans Haugeneder is co-leader of the Nat- Qualitative Reasoning, and the Pre- Intelligence. Menlo Park, Calif.: American ural Language Technology Group at dictability Problem. In Proceedings of the Association for Artificial Intelligence. 1989 Qualitative Reasoning Workshop. Siemens Corporate Research and Develop- Palo Alto. Struss, P. 1988d. Mathematical Aspects of ment. He holds a Master’s in linguistics Qualitative Reasoning. In International and logics from the University of Hunze, R. 1988. Resolving Anaphoric Ref- Journal of Artificial Intelligence in Engineer- Muenchen for his work on extensions of erences in a DRT-Based Dialogue System: ing 3:156–169. Montague semantics. His key interests in Part 1, The Formal Discourse Model, natural language understanding focus on WISBER Report 24, Saarbruecken Univ. Struss, P. 1988e. Mathematical Aspects of Qualitative Reasoning—Part Two: Differ- parsing models, descriptive formalisms for Meier, M., ed. 1988. SEPIA Version 2.0, ential Equations, Technical Report, INF2- linguistic knowledge sources, and User Manual, Technical Report, European ARM-7-88, Siemens AG. domain-independent language processing Computer Industry Research Centre. Struss, P. 1987. Multiple Representation of systems. Currently, he is at the German Reinfrank, M. 1989. Logical Foundations Structure and Function. In Expert Systems Research Center for AI in Saarbrucken, of Nonmonotonic Truth Maintenance. In in Computer-Aided Design, ed. J. Gero. where he is leading a project on human- Proceedings of the Fourth Portugese AI Amsterdam: North-Holland. computer cooperation and communica- Conference, ed. J. Martins. Berlin: tion in distributed environments. Springer. Struss, P., and Dressler, O. 1989. Physical Negation—Integrating Fault Models into Reinfrank, M., and Dressler, O. 1989. On the General Diagnostic Engine. In Pro- the Relation between Truth Maintenance ceedings of the Eleventh International and Non-Monotonic Logics. In Proceed- Joint Conference on Artificial Intelli- Peter Struss is leader of the Advanced ings of the Eleventh International Joint gence. Menlo Park, Calif.: International Conference on Artificial Intelligence. Reasoning Methods Group at Siemens Cor- Joint Conferences on Artificial Intelli- porate Research Menlo Park, Calif.: International Joint gence. Conferences on Artificial Intelligence. and Development. He received his Ph.D. Tiden, E. 1989. Rapid Development of in computer science from the University Reinfrank, M., and Freitag, H. 1988. Rules VLSI CAD Tools with PROLOG-XT, Tech- of Kaiserlautern for his research on quali- and Justifications: A Uniform Approach to nical Report, INF2-ASE-4-89, Siemens AG. tative reasoning with a focus on mathe- Reason Maintenance and Non-Monotonic Tiden, E. 1988. Symbolic Verification of matical formalization and analysis of Inference. In Proceedings of the Interna- qualitative calculi. His key interests are tional Conference on Fifth Generation Switch-Level Circuits Using a Prolog Enhanced with Unification in Finite Alge- model-based reasoning and the integra- Computer Systems. Tokyo: Institute for tion of qualitative reasoning and non- New Generation Computer Technology. bras. In Proceedings IFIP WG 10.2 Confer- ence. Glasgow. monotonic reasoning, including problems Ruckert, M., and Voges, U. 1989. WIFEX— such as the relations between qualitative WInterweizen Fungizid EXperte, Technical modeling and default reasoning in diag- Report, INF2-ASE-6-89, Siemens AG. nostic systems, the role of commonsense Schachtl, S. 1988. The Problem of Over- Wolfram Buettner received his diploma in concepts in engineering problem solving, generation in Parsing Processes and the mathematics from the University of Hei- and the interaction between model-based Aid of Linguistic Generalizations. In Pro- delberg in 1975 and a Ph.D. in mathemat- and experience-based diagnostic reason- ceedings of the Fourth Austrian Confer- ics from Tulane University in 1978. In ing. His current work is aimed at founda- ence on Artificial Intelligence, Vienna 1985, he joined Siemens Corporate tions for model-based diagnostic systems Workshop on Knowledge-Based Natural Research, where he currently heads the that can deal with significant real applica- Language Processing, Informatik-Fach- Knowledge Processing Laboratory. His tions. berichte. Berlin: Springer. research interests include the design of Schmid, L. 1988. Case-Driven Extension Prolog extensions for circuit design and of the Lexicon for Verbs in SEPP, Internal algorithmic aspects of neural networks. Report, Siemens AG. He is also affiliated with the University of Kaiserlautern, where he is a professor of Schuermann, B. 1989. Generalized Adap- computer science.

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