Dept. of Computer and Information science, Linköping University
Last updated: Tue, 02 Dec 1997 11:02:26
Ahrenberg, L., Jönsson, A., and Dahlbäck, N. (1991). Discourse Representation and Discourse Management for a Natural Language Dialogue System. Technical Report LiTH-IDA-R-91-21, Department of Computer and Information Science, Linköping University, Sweden. Also in Proc. of The Second Nordic Conference on Text Comprehension in Man and Machine (NOTEX'90), Täby-Stockholm, Sweden, 1990. (bibtex),
Abstract: In this paper we discuss some requirements on natural language interfaces that are needed for supporting connected dialogue, and propose methods for meeting these requirements in the context of a system that has been developed at our department over the last couple of years. On the basis of data collected in Wizard-of-Oz simulations we argue that the dynamic discourse representation needed for a given application can be structured in terms of a tree of dialogue objects (moves, initiative-response units) and a score board, i.e. a list of parameters each of which keeps some information relevant to the system's interpretation and generation tasks. We also argue that the domain knowledge needed for supporting reference resolution can, and should be obtained from data of this kind.
Bäckström, C. and Klein, I. (1991). On the Planning Problem in Sequential Control. Technical Report LiTH-IDA-R-91-37, Department of Computer and Information Science, Linköping University, Sweden. This report also appears in the proceedings of the 30th IEEE Conference on Decision and Control, 11-13 December 1991 Brighton, England. (bibtex),
Abstract: Sequential control is a common control problem in industry. Despite its importance fairly little theoretical research has been devoted to this problem. We study a subclass of sequential control problems, which we call the SAS-PUBS class, and present a planning algorithm for this class. The algorithm is developed using formalism from artificial intelligence (AI). For planning problems in the SAS-PUBS class the algorithm finds a plan from a given initial state to a desired final state if and only if any plan exists solving the stated planning problem. Furthermore the complexity of the given algorithm increases polynomially with the number of state variables.
Bäckström, C. and Klein, I. (1991). Parallel Non-Binary Planning in Polynomial Time: The SAS-PUS Class. Technical Report LiTH-IDA-R-91-11, Department of Computer and Information Science, Linköping University, Sweden. A short version is accepted to the 12th International Joint Conference on Artificial Intelligence (IJCAI'91). Sydney, Australia, August 24-30, 1991. (bibtex),
Abstract: This paper formally presents a class of planning problems, the SAS-PUS class, which allows non-binary state variables and parallel execution of actions. The class is proven to be tractable, and we provide a sound and complete, polynomial time algorithm for planning within this class. Since the SAS-PUS class is an extension of the previously presented SAS-PUBS class, this result means that we are getting closer to tackling realistic planning problems in sequential control. In such problems, a restricted problem representation is often sufficient but the size of the problems make tractability an important issue.
Bonnier, S., Nilsson, U., and Näslund, T. (1991). A Simple Fixed Point Characterization of Three-valued Stable Model Semantics. Technical Report LiTH-IDA-R-91-01, Department of Computer and Information Science, Linköping University, Sweden. Also accepted for publication in Processing Letters. (bibtex),
Abstract: No abstract available
Boye, J. (1991). S-SLD-resolution --- An Operational Semantics for Logic Programs with External Procedures. Technical Report LiTH-IDA-R-91-18, Department of Computer and Information Science, Linköping University, Sweden. Also accepted to the 3rd International Symposium on Programming Language Implementation and Logic Programming, Passau, Germany, August 26-28, 1991. (bibtex),
Abstract: S-SLD-RESOLUTION --- AN OPERATIONAL SEMANTICS FOR LOGIC PROGRAMS WITH EXTERNAL PROCEDURESThis paper presents a new operational semantics for logic programs with external procedures, introduced in [BM88]. A new resolution procedure S-SLD-resolution is defined, in which each step of computation is characterized by a goal and a set of equational constraints, whose satisfiability cannot be decided with the information at hand. This approach improves the completeness of the resulting system, since further computation may result in the information needed to solve some earlier unsolved constraints. We also state a sufficient condition to distinguish a class of programs where no unsolved constraints will remain at the end of computation.
Dahlbäck, N. (1991). Empirical Analysis of a Discourse Model for Natural Language Interfaces. Technical Report LiTH-IDA-R-91-31, Department of Computer and Information Science, Linköping University, Sweden. Also in Proc. of the 13th Annual Conference of the Cognitive Science Society (COG SCI -91), August 7-10, 1991, Chicago, Illinois, USA. (bibtex),
Abstract: A structural model of discourse for natural language interaction developed for the LINLIN-system is evaluated using the Wizard-of-Oz metod. 21 dialogues were collected using five different background systems, making it possible to vary the type and number of tasks possible to perform by the users. The results indicate that the structural complexity of the discourse in man-machine dialogues is simpler than most human dialogues, at least for information retrieval and some types of ordering systems, suggesting that computationally simpler discourse models can be used in these domains.
Doherty, P. and Lukaszewicz, W. (1991). NML3 --- An Non-monotonic Logic with Explicit Defaults. Technical Report LiTH-IDA-R-91-13, Department of Computer and Information Science, Linköping University, Sweden. To appear in the Journal of Applied Non-Classical Logics, 1991. (bibtex),
Abstract: We present a non-monotonic logic with explicit defaults, NML3, characterized by the following features: (1) The use of the strong Kleene three-valued logic as a basis. (2) The addition of an explicit default operator which enables distinguishing tentative conclusions from ordinary conclusions in the object language. (3) The use of the idea of preferential entailment to generate non-monotonic behavior. The central feature of the formalism, the use of an explicit default operator with a model theoretic semantics based on the notion of a partial interpretation, distinguishes NML3 from most of the existing formalisms. By capitalizing on the distinction between tentative and ordinary conclusions, NML3 provides increased expressibility in comparison to many of the standard non-monotonic formalisms and greater flexibility in the representation of subtle aspects of default reasoning. We show this through example. Technically, NML3 belongs to the class of preferential logics. The semantics is model-theoretic with well motivated underlying intuitions and is multi-valued. An explicit default operator is defined with an intuitive declarative semantics. We show (in the context of recent work by Makinson and Kraus et. al. that NML3's consequence relation is well-behaved.
Drabent, W. (1991). Constructive Negation by Fail Answers. Technical Report LiTH-IDA-R-91-23, Department of Computer and Information Science, Linköping University, Sweden. Also published in the Journal Acta Informatica, 1992. (bibtex),
Abstract: No abstract available
Fjällström, P.-O. (1991). Polyhedral Approximation of Bivariate Functions. Technical Report LiTH-IDA-R-91-24, Department of Computer and Information Science, Linköping University, Sweden. Also in Proc. of Third Canadian Conference on Computational Geometry, Vancouver, B.C., Canada, August 5-10, 1991. (bibtex),
Abstract: No abstract available
Fjällström, P.-O., Katajainen, J., and Petersson, J. (1991). Algorithms for the All-Nearest-Neighbors Problem. Technical Report LiTH-IDA-R-91-25, Department of Computer and Information Science, Linköping University, Sweden. Also in Proc. of Conf. on System Modelling and Optimization, International Federation for Information Processing (IFIP), Zurich, Switzerland, September 2-6, 1991. (bibtex),
Abstract: No abstract available
Fribourg, L. (1991). A Decision Procedure for a Subtheory of Linear Arithmetic with Lists. Technical Report LiTH-IDA-R-91-33, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: No abstract available
Fritzson, D. and Fritzson, P. (1991). Equational Modeling of Machine Elements --- Applied to Rolling Bearings. Technical Report LiTH-IDA-R-91-05, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: Machine element analysis has the goal of describing functionality, and other important aspects of machine elements in theoretical form. A rolling bearing is a typical example of a machine element. There are a large number of different rolling bearing types. Especially for geometry and tribology it is of great value to have a general approach that is valid for a wide range of bearing types. Thus, we have defined a general equational model of rolling bearings which is presented in this paper. The structure of the model is general, in three dimensions, and applies to many types of rolling bearings. Part of this generality is obtained by using parametric surfaces. In order to keep the presentation of the model understandable, we have simplified many details. Still, the model and one solution require approximately 400 equations. It should be emphasized that the structure of the model is quite realistic. The model is also extensible, e.q. simple submodels of detailed properties can be made more complex without altering the overall structure.The second issue covered in this paper is how ideas from object-oriented programming and modeling can be applied to machine element analysis. The models thus obtained are both easier to understand, better structured, and allow a higher degree of reuse than conventional models. Our conclusion is that an object-oriented model description is natural for the machine element analyst and is suitable for machine element analysis.
Fritzson, P. (1991). ObjectMath - Object Oriented Mathematical Modeling in Scientific Computing, Applied to Machine Elements Analysis. Technical Report LiTH-IDA-R-91-06, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: The current state of the art in programming for scientific computing is still very low level. Much numerical software is being developed the traditional way in FORTRAN. This is especially true in application areas such as machine elements analysis, where complex non-linear problems are standard. In order to improve this situation, we are developing a practically usable high-level object-oriented programming environment for scientific computing, which supports programming in equations instead of low-level procedural programming, and permits better reuse of equations in mathematical models.As an essential component in this environment we have designed and implemented a modeling and programming language called ObjectMath (Object oriented Mathematical language for scientific computing). It is a hybrid language that combines object oriented language features with a computer algebra language, in this case Mathematica. Using ObjectMath, it is possible to model classes of equation objects, and to support inheritance of equations. Geometrical constraints are expressed through connection objects and coordinate system objects, and through use of parametric surface techniques. The environment is designed to handle realistic problems. This is achieved by allowing the user to specify transformations and simplifications of formulae in the model, in order to arrive to a representation which is solvable. When necessary, equations can be transformed to C++ code for efficient numerical solution. A prototype version of the environment is currently being used for a 3-dimensional example model of 200 equations describing a rolling bearing.
Fritzson, P. and Fritzson, D. (1991). The Need for High-Level Programming Support in Scientific Computing Applied to Mechanical Analysis. Technical Report LiTH-IDA-R-91-04, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: We describe the current state of the art in computerized support of mathematical and numerical modeling for mechanical analysis. An overview of relevant high-level languages, computer algebra systems, and hybrid symbolic-numerical systems is also given. Several problems with current tools are identified, and a high-level programming environment is proposed as a solution. Such an environment should include object oriented model description, symbolic formula manipulation, generation of numeric code, automatic use of equation solvers and optimization techniques, in addition to graphical presentation of model and simulation data.
Fritzson, P., Fritzson, D., Viklund, L., and Herber, J. (1991). Transformation of Equation-Based Real-World Models to Efficient Code, Applied to Machine Elements Geometry. Technical Report LiTH-IDA-R-91-38, Department of Computer and Information Science, Linköping University, Sweden. Also in Proceedings of the 1st National Swedish Symposium on Real-Time Systems, Uppsala, August 19-20, 1991. (bibtex),
Abstract: Software which deals with the real external world usually includes a model of relevant aspects of this world. A high level and concise way of expressing such models is through mathematics - equations and formulae, which can model geometry and other properties. However, software which interacts with the real world, usually real-time software, is very dependent on efficient execution of the code which implements the model. A typical example is a robot arm, where the software must include a computationally efficient model of the arm geometry and surroundings in order to precisely guide the arm movement.In our approach we combine the advantages of both a high level abstract model representation and execution of efficient code. This is achieved by providing symbolic transformations of the model: i.e. to minimize the part which is solved numerically and transform the model into a computationally efficient form. To this end, we have designed and implemented a prototype object-oriented programming environment to support the process. The environment can handle realistic problems, since the user can supply expertise in terms of transformations and simplifications of equations.An essential component in this environment is a modeling and programming language called ObjectMath (Object oriented Mathematical language for scientific computing). It is a hybrid language that combines object oriented language features with a computer algebra language, in this case Mathematica. Using ObjectMath, it is possible to model classes of equation objects, and to support inheritance of equations. Geometrical constraints are expressed through connection objects and coordinate system objects, and through use of parametric surface techniques. When necessary, equations can be transformed to C++ code for efficient numerical solution. A prototype version of the environment is currently being used for an example model of 200 equations describing a rolling bearing in three dimensions.
Gu, X., Kuchcinski, K., and Peng, Z. (1991). Testability Measure with Reconvergent Fanout Analysis and Its Applications. Technical Report LiTH-IDA-R-91-17, Department of Computer and Information Science, Linköping University, Sweden. This paper will be published in Microprocessing and Microprogramming the EUROMICRO Journal, Vol. 33, 1991. (bibtex),
Abstract: Many testability measure tools have been developed to reduce computational complexity of automatic test pattern generation (ATPG). These tools, by using linear algorithm or heuristics, obtain quantitative testability measure for each line within a circuit. Such testability measure is usually based on the measures of controllability and observability which do not always reflect the real situation of testability. One reason for this is that reconvergent fanouts can sometimes cause redundant faults. This paper presents a method of computing testability with reconvergent fanout checking and redundant fault detecting, while keeping a reasonable computation complexity. The result obtained is used to guide design transformations in VLSI high-level synthesis so as to generate circuits which are less costly for both ATPG and testing process.
Jönsson, A. (1991). A Dialogue Manager Using Initiative-Response Units and Distributed Control. Technical Report LiTH-IDA-R-91-03, Department of Computer and Information Science, Linköping University, Sweden. Also presented at the 5th Conference of the European Chapter of the ACL, Berlin, Germany, April 9-11, 1991. (bibtex),
Abstract: This paper describes a system for managing dialogue in a natural language interface. The proposed approach uses a dialogue manager as the overall control mechanism. The dialogue manager accesses domain independent resources for interpretation, generation and back-ground system access. It also uses information from domain dependent knowledge sources, which are customized for various applications. Instead of using complex plan-based reasoning, the dialogue manager uses information about possible interaction structures and information from the specific dialogue situation to manage the dialogue. This is motivated from the analysis of a series of experiments where users interacted with a simulated natural language interface. The dialogue manager integrates information about segment types and moves into a hierarchical dialogue tree. The dialogue tree is accessed through a scoreboard which uses exchangeable access functions. The control is distributed and the dialogue is directed from action plans in the nodes in the dialogue tree
Jönsson, A. (1991). A Natural Language Shell and Tools for Customizing the Dialogue in Natural Language Interfaces. Technical Report LiTH-IDA-R-91-10, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: The language used in an interaction between a human and a computer depends on the application as well as the user. This paper describes a method for building domain specific natural language interfaces by updating knowledge bases for a domain independent natural language shell. The interface uses a uniform knowledge representation for linguistic, dialogue and domain knowledge. Further, it contains a dialogue manager which can be customized for different applications by changing or updating dialogue objects describing different interaction situations. Information about the interactions is gathered from experiments with a simulated human-computer interface, Wizard of Oz experiments. These are incorporated into the interface using a system which extracts information from a tagged corpus and inserts it into the knowledge bases. Information on all the different levels of an NLI can be extracted from the corpus in this way, but in this paper emphasis is laid on extracting and incorporating dialogue management information.
Kågedal, A. and Kluz'niak, F. (1991). Enriching Prolog With S-unification. Technical Report LiTH-IDA-R-91-12, Department of Computer and Information Science, Linköping University, Sweden. Also in "Phoenix" Seminar on Declarative Programming, Hohritt, Germany, November 1991, Springer-Verlag, LNCS. (bibtex),
Abstract: No abstract available
Kamkar, M. (1991). Interprocedural Dynamic Slicing Applied to Algorithmic Debugging. Technical Report LiTH-IDA-R-91-20, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: No abstract available
Kamkar, M. (1991). An Overview and Comparative Classification of Static and Dynamic Program Slicing. Technical Report LiTH-IDA-R-91-19, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: Program slicing is a method for decomposing programs into segments or slices. A program slice contains all statements that could have influenced the value of a variable of interest at some program point. The technique of program slicing has up to now been applied within a number of areas such as software maintenance, program verification, program integration, testing, parallel processor distribution and especially program debugging. A slice of a program is computed either by using static information, in which case it is called a static slice, or with the help of dynamic information, in which case it is called a dynamic slice. A static slice of a program contains much broader but less precise information and thus it tends to be much more voluminous than the corresponding dynamic slice. The reason is that for a specified variable in a program the static slice is the collection of all possible computations of values of that variable. A dynamic slice, on the other hand, isolates the unique computation of the value of the specified variable for a certain program execution. Thus, it narrows the size of the computed slice compared to the corresponding static slice.The current literature on slicing is becoming unwieldy with many different notions and methods. This paper attempts to bring order into disorder by identifying and classifying different notions of program slicing and their applications. A new notion of execution slice and a method for interprocedural dynamic slicing are introduced as well.
Kluz'niak, F. (1991). PageBreak: An Exercise in Specification and Derivation. Technical Report LiTH-IDA-R-91-27, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: No abstract available
Kluz'niak, F. (1991). SPILL: A Specification Language Based on Logic Programming. Technical Report LiTH-IDA-R-91-28, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: No abstract available
Kluz'niak, F. (1991). Towards Practical Executable Specifications in Logic. Technical Report LiTH-IDA-R-91-26, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: No abstract available
Kuchcinski, K. (1991). Toward Automatic Tets Pattern Generation for VHDL Description. Technical Report LiTH-IDA-R-91-36, Department of Computer and Information Science, Linköping University, Sweden. Also in Proceedings of the EURO-VHDL 91, Sweden, Stockholm, September 8-11, 1991. (bibtex),
Abstract: This paper describes an approach for defining a model for the VHDL descriptions which can be used for test generation purpose. The VHDL description can be transformed to this model by semantic preserving transformations without lost of information needed for test generation purpose. Together with the model definition a unified fault model is defined which can be easily related to well known fault models defined on different levels of hardware abstraction (such as stack-at-0/1, wrong function selection and controller state selection fault). Finally, a discussion about possible test generation procedures based on the model is included.
Lambrix, P. (1991). Temporal Aspects of Composite Objects. Technical Report LiTH-IDA-R-91-14, Department of Computer and Information Science, Linköping University, Sweden. Also accepted to the Golden West International Conference on Intelligent Systems, Reno Nevada 1992. (bibtex),
Abstract: No abstract available
Loborg, P. and Törne, A. (1991). A Hybrid Language for the Control of Multimachine Environments. Technical Report LiTH-IDA-R-91-09, Department of Computer and Information Science, Linköping University, Sweden. Accepted to the 4th Conference on Industrial and Engineering Applications of Artificial Intelligence and Expert Systems, Hawaii, June 2-5, 1991. (bibtex),
Abstract: We report here on the development of a language and editor for use by operators and production engineers to instruct machine environments (manufacturing cells), as part of the ARAMIS-project. The language design is focused on making the computer transparent in the task of programming a manufacturing cell, thus making it easier for nonprogrammers to instruct the cell. The language is graphical, and is a hybrid between a traditional and a rule-based language. The conflict resolution problem is dealt with by defining possible amalgamations of rules, a process supported by presentational views in the editor.
Malec, J. (1991). How To Pass an Intersection, or Automata Theory is Still Useful. Technical Report LiTH-IDA-R-91-08, Department of Computer and Information Science, Linköping University, Sweden. To be presented at SCAI'91, Roskilde, Denmark, May 21-24, 1991. (bibtex),
Abstract: In this paper I present several knowledge representation (KR) languages used within one project, and show relationships between these languages. I try to persuade that when designing a complex AI system, one should use different KR formalisms, namely the ones most suitable for purposes of different subsystems, and devise an appropriate tool for data (or knowledge) interchange between these subsystems. The KR formalisms need not be the ones traditionally associated with AI ---there are lots of other valuable tools. The argument is presented using one particular example of an AI system being designed within the ProArt part of the PROMETHEUS project.
Nadjm-Tehrani, S. (1991). Analysis of the Overtaking Scenario: Specification of an Autonomous Car and a Driver Support System. Technical Report LiTH-IDA-R-91-07, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: Representation of real world phenomena in terms of theories in logic and drawing inferences from the theories are known to be cumbersome and impractical for applications of modest complexity. In this paper I advocate one possible use of logic in designing decision support systems. It is suggested that logic-based languages, even if not used in the final system dealing with the application, are a good specification language which also provide the possibility of rapid prototyping. In addition, logic can be used for analysis of the solution, arriving at meta-theories which can benefit the final application. These issues are discussed in the context of a non-trivial application: that of providing support to a driver in a co-driver system.
Nebel, B. and Bäckström, C. (1991). On the Computational Complexity of Temporal Projection and some Related Problems. Technical Report LiTH-IDA-R-91-34, Department of Computer and Information Science, Linköping University, Sweden. Also published as DFKI Research Report RR-91-34, German Research Center for Artificial Intelligence (DFKI), Saarbrucken, Germany. The results in this report has been divided into conference papers that will appear in proceedings of the AAAI-92, conference, San Jose, Ca USA, jul 12-17, 1992 and in proceedings of the ECAI-92 conference, Vienna, Austria, Aug 3-7, 1992 respectively and has been accepted for publication in Artificial Intelligence (ie.AI Journal). (bibtex),
Abstract: Abstract: One kind of temporal reasoning is temporal projection---the computation of the consequences for a set of events. This problem is related to a number of other temporal reasoning tasks such as story understanding, plan validation, and planning. We show that one particular simple case of temporal projection on partially ordered events turns out to be harder than previously conjectured. However, given the restrictions of this problem, planning and story understanding are easy.Additionally, we show that plan validation, one of the intended applicationsof temporal projection, is tractable for an even larger class of plans. The incomplete decision procedure for the temporal projectionproblem that has been proposed by other authors, however, fails to becomplete in the case where we have shown plan validation to be tractable
Nilsson, U. (1991). Abstract Interpretation: A Kind of Magic. Technical Report LiTH-IDA-R-91-02, Department of Computer and Information Science, Linköping University, Sweden. Also accepted to the 3rd International Symposium on Programming Language Implementation and logic Programming (PLILP), Passau, Germany, August 26-28, 1991. (bibtex),
Abstract: No abstract available
Peng, Z., Fagerström, J., and Kuchcinski, K. (1991). A Unified Approach to Evaluation and Design of Hardware/Software Systems. Technical Report LiTH-IDA-R-91-16, Department of Computer and Information Science, Linköping University, Sweden. Also accepted to the ICSE (13th International Conference on Software Engineering) Workshop on Software/hardware Codesign, Austin, Texas, May 13, 1991. (bibtex),
Abstract: This paper presents a unified approach to the design of application-specific systems which consist of both hardware and software components. Our approach is based on the development of an formal intermediate design representation which can be used to capture both hardware and software semantics. Evaluation of a hardware/software design can then be done automatically by simulating the design representation. The simulation results can directly be used to guide exploration of the design space so as to produce cost-effective solutions. The proposed approach supports a top-down design methodology which starts with a high-level behavioral specification and transforms it step-by-step into an efficient implementation by making design trade-offs between hardware and software.
Przymusinski, T. C. (1991). Semantics of Disjunctive Logic Programs and Deductive Database. Technical Report LiTH-IDA-R-91-32, Department of Computer and Information Science, Linköping University, Sweden. Accepted to The Second International Conference on Decuctive and Object-Oriented Databases, Munich, Germany, December, 1991. (bibtex),
Abstract: No abstract available
Przymusinski, T. C. (1991). Stable Semantics for Disjunctive Programs. Technical Report LiTH-IDA-R-91-22, Department of Computer and Information Science, Linköping University, Sweden. This paper will appear in the special issue of the Journal of New Generation Computing. (bibtex),
Abstract: No abstract available
Sandewall, E. (1991). Features and Fluents. An agenda and logic-based framework for the Representation of Knowledge about Dynamical Systems. Review version of Chapters 1 and 3-7. Technical Report LiTH-IDA-R-91-29, Department of Computer and Information Science, Linköping University, Sweden. This is a preliminary version of parts of a forthcoming book. (bibtex),
Abstract: This report is a review version of parts of a forthcoming book on the logic of reasoning about actions and time, and on the various aspects of the frame problem including the inertia problem, the qualification problem, and the ramification problem.An approach which addresses all three of those problems is described in the present report, based on a number of previous conference papers by the present author. The report also defines a catalogue of test scenarios for temporal reasoning. Some of the current approaches to temporal reasoning in the A.I. literature are reviewed, and it is analyzed whether they obtain the intended conclusions for each of the test scenarios. It is observed that in a surprisingly large number of cases, the currently most popular approaches fail to obtain the intended conclusions. In some cases too few conclusions, but in a larger number of cases too many conclusions are obtained.
Söderman, U. and Strömberg:, J.-E. (1991). Combining Qualitative and Quantitative Knowledge to Generate Models of Physical Systems. Technical Report LiTH-IDA-R-91-15, Department of Computer and Information Science, Linköping University, Sweden. A Short version is accepted to the 12th International Joint Conference on Artificial Intelligence (IJCAI-91) Sydney, Australia, August 24-30, 1991. (bibtex),
Abstract: All major approaches to Qualitative Reasoning rely on the existence of a model of the physical system. However, the task of finding a model is usually far from trivial. Within the area of electrical engineering, model building methods have been developed to automatically deduce models from measurements. In this paper we explicitly show how to incorporate qualitative knowledge in order to apply these methods to situations where they do not behave satisfactorily. A program has been developed and applied to a non-trivial example. The qualitative input, in terms of an incomplete bond graph, and the resulting output can be used to form a more complete bond graph. This more informative model is suitable for further reasoning.
Strömbäck, L. (1991). Unifying Disjunctive Feature Structures. Technical Report LiTH-IDA-R-91-35, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: This paper describes an algorithm for unifying disjunctive feature structures. Unlike previous algorithms, except Eisele & Dörre (1990), this algorithm is as fast as an algorithm without disjunction when disjunctions do not participate in the unification, it is also as fast as an algorithm handling only local disjunctions when there are only local disjunctions, and expensive only in the case of unifying full disjunction. The description is given in the framework of graph unification algorithms which makes it easy to implement as an extension of such an algorithm.