Last updated: Tue, 02 Dec 1997 11:02:44
Axelsson, K. (1994). Informationssystemstrategiers betydelse vid förändring av informationssystem.. Technical Report LiTH-IDA-R-94-47, Department of Computer and Information Science, Linköping University, Sweden. Föredrag presenterat på Sundsvall 42, Sundsvall, 18-20 oktober 1994. (bibtex),
Abstract: No abstract available
Bäckström, C. (1994). Executing Parallel Plans Faster by Adding Actions. Technical Report LiTH-IDA-R-94-22, Department of Computer and Information Science, Linköping University, Sweden. This paper will appear in the proceedings of the 11th European Conference on Artificial Intelligence, Amsterdam, Netherlands, August 1994. Wiley. (bibtex),
Abstract: If considering only sequential execution of plans, the execution time of a plan will increase if adding actions to it. However, if also considering parallel execution of plans, then the addition of actions to a plan may sometimes decrease the execution time. It is further shown that plans which are sub-optimal in this way are likely to be frequently generated by standard partial-order planners. Unfortunately, optimizing the execution time of a plan by adding actions is NP-hard and cannot even be approximated within a constant ratio.
Bäckström, C. (1994). Finding Least Constrained Plans and Optimal Parallel Executions is Harder than we thought. Technical Report LiTH-IDA-R-94-20, Department of Computer and Information Science, Linköping University, Sweden. This paper is published in C. Bäckström and E. Sandewall (eds.), Current Trends in AI Planning: EWSP'93---2nd European Workshop on Planning, Vadstena, Sweden, Dec. 1993. IOS Press. It will also be presented at the workshop on Algorithms, Complexit and Commonsense Reasoning at the 11th European Conference on Artificial Intelligence, Amsterdam, Netherlands, Aug. 1994. (bibtex),
Abstract: It seems to have been generally assumed in the planning community that it is easy to compute a least-constrained partially ordered version of a total-order plan. However, it is not clear what this concept means. Five candidates for this criterion are defined in this paper, and it turns out that the only ones giving some reasonable optimality guarantee are NP-hard to compute. A related problem is to find a shortest parallel execution of a plan, also proven NP-hard. Algorithms can be found in the literature which are claimed to solve these problems optimally in polynomial time. However, according to the NP-hardness of the problems, this is impossible unless P=NP, and it is explained in this paper why the algorithms fail. The algorithms are, instead, reconsidered as approximation algorithms, but it is shown that neither algorithm gives any constant performance guarantee. This is not surprising, however, since both problems turn out not to be approximable within a constant ratio.
Bennet, T., Olhager, J., and Rapp, B. (1994). Datorisering av MPS-system i svenska företag 1987-1993. Technical Report LiTH-IDA-R-94-41, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: (Denna rapport är inskickad för publicering i tidningen Verkstäderna i början av 1995. En något annorlunda version är också publicerad som proceeding från The IFIP WG5.7 Working Conference on Evaluation of Production Management Methods Gramado, Brazil, 21-24 March 1994)
Carlshamre, P. (1994). A Field Study in Usability Engineering: Bringing in the Technical Communicators.. Technical Report LiTH-IDA-R-94-44, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: For the last 20 years, the human-computer interaction research community has provided a multitude of methods and techniques intended to support the development of usable systems, but the impact on industrial software development has been limited. One of the reasons for this limited success is argued to be the gap between traditional academic theory generation and industrial practice. Furthermore, technical communicators (TCs) have until recently played a subordinate role in software design, even in usability-oriented methods. Considering their close relation to the users of the developed systems, and to the usability issue itself, they con- stitute a hidden resource, which potentially would contribute to the benefit of more usa- ble systems. We formed the Delta project as a joint effort between industry and academia. The objec- tives of the project were to jointly develop usability-oriented method extensions, adapted for a particular industrial setting, and to account for the specialist competence of the TCs in the software development process. This report is a qualitative study of the development, introduction and evaluation of the Delta method extension. The analysis provides evidence in favor of a closer collaboration between system developers (SDs) and TCs. An additional outcome of the in-depth study is a proposed redefinition of the extended interface concept, taking into account the inseparability of user documenta- tion and user interface, while providing a natural common ground for a closer collabo- ration between SDs and TCs.
Doherty, P. (1994). Notes on PMON Circumscription. Technical Report LiTH-IDA-R-94-43, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: This report describes the current state of work with PMON, a logic for reasoning about action and change. PMON has been assessed correct for the K-IA class using Sandewall's Features and Fluents framework which provides tools for assessing the correctness of logics of action and change. A syntactic characterization of PMON is provided in terms of a circumscription axiom which is shown to be reducible to a first-order formula. This creates the possibility for efficient implementation of the logic, a topic discussed in this report. In addition, besides considering the frame problem, PMON is extended to PMONR in order to deal with some restricted types of the ramification problem. It is also shown that PMONR is reducible to the first-order case. A number of benchmark examples are analyzed which show the advantages of reduction to the monotonic first-order case. In addition, an appendix is provided with a detailed description of the surface language for action scenarios and its reduction to the base logic FL, a first-order sorted logic.
Doherty, P., Lukaszewicz, W., and Szalas, A. (1994). Computing Circumscription Revisited: A Reduction Algorithm. Technical Report LiTH-IDA-R-94-42, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: In recent years, a great deal of attention has been devoted to logics of "commonsense" reasoning. Among the candidates proposed, circumscription has been perceived as an elegant mathematical technique for modeling nonmonotonic reasoning, but difficult to apply in practice. The major reason for this is the 2nd-order nature of circumscription axioms and the difficulty in finding proper substitutions of predicate expressions for predicate variables. One solution to this problem is to compile, where possible, 2nd-order formulas into equivalent 1st-order formulas. Although some progress has been made using this approach, the results are not as strong as one might desire and they are isolated in nature. In this article, we provide a general method which can be used in an algorithmic manner to reduce circumscription axioms to 1st-order formulas. The algorithm takes as input an arbitrary 2nd-order formula and either returns as output an equivalent 1st-order formula, or terminates with failure. The class of 2nd-order formulas, and analogously the class of circumscriptive theories which can be reduced, provably subsumes those covered by existing results. We demonstrate the generality of the algorithm using circumscriptive theories with mixed quantifiers (some involving Skolemization), variable constants, non-separated formulas, and formulas with n-ary predicate variables. In addition, we analyze the strength of the algorithm and compare it with existing approaches providing formal subsumption results.
Eles, P., Kuchcinski, K., Peng, Z., and Doboli, A. (1994). Back-Annotation of VHDL Behavioral Models for Postsynthesis Simulation. Technical Report LiTH-IDA-R-94-36, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: The paper presents an approach to back-annotation of VHDL specifications containing time- constraints, for postsynthesis behavioral simulation. As a distinct feature, the mechanism does not rely on the well-timed assumption. This corresponds to the synthesis strategy adopted by the CAMAD system: different execution times can be synthesized for the alternative paths through a constrained statement sequence, with the restriction that all these times are consistent with the user specified timing requirements. Thus, our back-annotation strategy solves the tracing of the actual path run through a time-constrained sequence and the dynamic selection of the respective synthesized time for simulation. The actual time is selected during simulation using the dynamically constructed pattern that corresponds to the executed path. The elaborated algorithms are illustrated in the paper by some examples.
Eles, P., Kuchcinski, K., Peng, Z., and Doboli, A. (1994). Specification of Timing Constraints in VHDL for High-Level Synthesis. Technical Report LiTH-IDA-R-94-37, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: This paper deals with the problem of timing constraint specification in VHDL for high-level synthesis purposes. We first discuss some possible approaches and define the basic requirements for a notation. According to these requirements a notation based on predefined subprograms is proposed for the specification of constraints on sequences of statements. The notation accepts nested timing constraints with specification of minimum, maximum, range, and exact limits and supports back-annotation for postsynthesis simulation. We have also provided support for specification of timing constraints across process borders. The mechanism is based on the concurrent assert statement and allows specification of timing constraints on signal events. One of the major problems discussed in the paper is consistency between the behavior of the simulation model and the synthesized hardware. We identify solutions to this problem in the frame of our two synthesis strategies and show in the paper how simulation/synthesis correspondence can be achieved for VHDL specifications containing both interacting processes and timing constraints.
Flodin, S. (1994). An Incremental Query Compiler with Resolution of Late Binding.. Technical Report LiTH-IDA-R-94-46, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: This paper presents the extensions made to the query compiler of an object-relational database management system (ORDBMS) to make it function incrementally and to make it resolve when late binding of function calls must be used. The object-oriented model consists of features such as operator overloading and inheritance which leads to the requirement of late binding of function calls. Late binding is not desirable since it can lead to inefficient execution plans due to the difficulty of optimizing late bound calls. Therefore a resolution mechanism of late binding, which recognize the unavoidable cases of late binding is very desirable. This resolution mechanism decides if early binding cannot be used and only then suggests late binding. Having the system to resolve when late binding must be used, the order in which functions are defined becomes significant to the consistency of the system. To make the system maintain consistency the query compiler needs to function incrementally and recompile existing functions whenever required.
Fritzson, P. (1994). Proceedings of the Poster Session of CC'94 - International Conference om Compiler Construction. Technical Report LiTH-IDA-R-94-11, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: No abstract available
Germundsson, R., Gunnarsson, J., Jansson, A., Krus, P., Morin, M., Nadjm-Tehrani, S., Plantin, J., Sethson, M., and Strömberg, J.-E. (1994). Complex Hybrid Systems I - A Study of available Tools and Specification of planned Work. Technical Report LiTH-IDA-R-94-29, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: The aim of this report is twofold. First, to provide a common framework and terminology for the participants of the Nutek supported COHSY project --- a multi-disciplinary academic-industrial cooperation on COmplex Hybrid SYstems. Second, to define more precisely the activities within the next few years of the project. Therefore, the current report should be considered as a project definition rather than a statement about the cosntructive work currently in progress.
Goldkuhl, G. (1994). Några problem vid datadriven strukturering av informationssystem.. Technical Report LiTH-IDA-R-94-53, Department of Computer and Information Science, Linköping University, Sweden. Presenterat på LISS 94 (Linköpings InformationsSystem Seminarium 1994), 20 april 1994, Linköpings universitet, Linköping. (bibtex),
Abstract: No abstract available
Goldkuhl, G. (1994). Välgrundad Metodutveckling. Presenterat på VITS. Technical Report LiTH-IDA-R-94-04, Department of Computer and Information Science, Linköping University, Sweden. Höstseminarium, September 28-29, 1993, Institutionen för Datavetenskap, Linköpings universitet. (bibtex),
Abstract: Rapporten behandlar frågeställningen hur man utvecklar goda metoder. Detta har stor relevans för området informationssystemutveckling, där olika typer av metoder utvecklas, studeras och brukas; men även inom många andra områden spelar metoder en stor roll. Rapporten behandlar metodbegreppet - metoders existens, innehåll, uppkomst och användning. Metodbegreppet relateras till andra kunskapsformer, som förklaringar, värden, kategorier, pespektiv och empiribeskrivningar. En utredning om vad som bör menas med välgrundad kunskap utförs. Detta leder fram till ett vidgat rationalitetsbegrepp: Argumentativ rationalitet. Olika processer att grunda metoder i reltion till andra kunskapsformer beskrivs. Välgrundad metodutveckling definieras som ett arbete där fokus växlas mellan metod, teori och empiri samt mellan design och prövning. Rapporten avslutas med en sammanfattande analys av metodstudier som vetenskaplig utveckling.
Göran Goldkuhl, D. F. (1994). Metodanalys - en beskrivning av metametoden SIMM.. Technical Report LiTH-IDA-R-94-52, Department of Computer and Information Science, Linköping University, Sweden. Föredrag presenterat på VITS Höstseminarium 1994, Linköping, 23-24 november 1994. (bibtex),
Abstract: No abstract available
Gu, X., Kuchcinski, K., and Peng, Z. (1994). Testability Analysis and Improvement from VHDL Behavioral Specifications. Technical Report LiTH-IDA-R-94-27, Department of Computer and Information Science, Linköping University, Sweden. Accepted to EURO-DAC'94 with EURO-VHDL'94 Conference, Grenoble, France, September 19-23, 1994. (bibtex),
Abstract: No abstract available
Karin Pettersson, Annie Röstlinger, A. B. (1994). Datadriven utveckling i kommun - en fallstudie om strukturering av informationssystem.. Technical Report LiTH-IDA-R-94-50, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: No abstract available
Karin Pettersson, O. E. (1994). VBS på Skogsbolag - en fallstudie om strukturering av informationssystem.. Technical Report LiTH-IDA-R-94-48, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: No abstract available
Karlsson, L. (1994). Specification and Synthesis of Plans Using the Features and Fluents Framework. Technical Report LiTH-IDA-R-94-28, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: An autonomous agent operating in a dynamical environment will face a number of different reasoning problems, one of which is how to plan its actions in order to pursue its goals. For this purpose, it is important that the agent represents its knowledge about the world in a coherent, expressive and well-understood way, in our case the temporal logics from Erik Sandewall's "Features and Fluents" framework. However, most existing planning systems make no use of temporal logics, but have specialised representations such as the Strips formalism and hierarchical task networks. In order to benefit from the techniques used by these planners, it is useful to analyse and reconstruct them within the given framework. This includes making explicit the ontological and epistemological assumptions underlying the planners; representing plans as entities of the temporal logic; and reconstructing the algorithms in terms of the new representation. The two planners Strips and Tweak have been analysed and reconstructed in this way.
Laurent Fribourg, H. O. (1994). Direct, Dual and Contrapositive Proofs by Induction.. Technical Report LiTH-IDA-R-94-45, Department of Computer and Information Science, Linköping University, Sweden. Accepted to LOPSTR 94 (Preproceedings), Pisa, Italy, June 1994. (bibtex),
Abstract: No abstract available
Lin Padgham, B. N. (1994). Combining Classification and Nonmonotonic Inheritance Reasoning: A First Step.. Technical Report LiTH-IDA-R-94-31, Department of Computer and Information Science, Linköping University, Sweden. Accepted to Proceedings of the Seventh International Symposium on Methodologies for Intelligent Systems, LNAI 689, PP 132-141, Trondheim, Norway. (bibtex),
Abstract: No abstract available
Malec, J. (1994). Bahaviour-Based Autonomous Systems: Towards an Analysis Framework. Technical Report LiTH-IDA-R-94-03, Department of Computer and Information Science, Linköping University, Sweden. Accepted to the 12th European Meeting on Cybernetics and Systems Research, Vienna, Austria, April 5-8, 1994. (bibtex),
Abstract: In this paper we address the crucial problem of the behaviour-based control, namely: given a set of behaviours connected in some way, what will be the result of their concurrent and independent execution? We present a very simple example showing that analysis of this problem is not at all simple, depending on a large number of variables. Moreover we suggest that usage of different design and implementation techniques could lead to a better insight into this problem.
Malec, J. (1994). On Implementing Behaviours Using a three-layered Architecture. Technical Report LiTH-IDA-R-94-21, Department of Computer and Information Science, Linköping University, Sweden. Accepted to Intelligent Robotic Systems'94, Grenoble, France, 11-15 July 1994. (bibtex),
Abstract: The problem of designing reactive autonomous systems has been the subject of much attention in recent years. The research has focused on designing systems which would possess the following attributes: 1. reactivity, in order to allow the system to cope with unpredictable changes in the dynamic environment while performing its mission; 2. robustness, meaning the ability to function in a variety of situations, including failure of some of its subsystems; 3. selectivity of attention, in order to effectively use existing resources of the system, such as computing power, or sensory equipment; 4. ability to pursue goals either defined by the designer, or by the system itself. One can distinguish several approaches to this problem. One of them is called ``behaviour-based'', because behaviour is the basic structure used for specifying control for an autonomous system. Another one is based on layered control architecture, where usually each layer has its own, well-defined task(s) to perform, often some software tools supporting implementation of those tasks, and some appropriate mechanism for passing control between the layers (or distributing it among them). Those two approaches are usually opposed to each other: ``Behaviourists'' claim that a rigid architecture requires excessive computational power and enforce too many constraints on the actual design and implementation. The other group claims that behaviour-based approach is unsuitable for applications requiring either sophisticated control algorithms, or symbolic reasoning (as e.g. planning) procedures, or both. Both criticisms are to some extent justified. In this paper we present an approach to implementing behaviour-based control using a three-layered architecture. In this way we intend to combine the advantages of both approaches.
Malec, J. (1994). A Unified Approach to Intelligent Agency. Technical Report LiTH-IDA-R-94-23, Department of Computer and Information Science, Linköping University, Sweden. Accepted to ECAI'94 Workshop on Agent Theories, Architectures and Languages, Amsterdam, Netherlands, 8-12 Aug 1994. (bibtex),
Abstract: The paper presents a unified approach to intelligent agency that has been developed by the members of the Laboratory for Knowledge Representation in Logic at the Department of Computer and Information Science, University of Linköping since 1986. The approach is based on the theory of Inhabited Dynamical Systems proposed and developed by Sandewall , on the integrated layered software architecture concept developed at our lab  and on the research on specification of reactive system behaviour pursued since 1990 .
Malec, J., Morin, M., and Palmqvist, U. (1994). Driver Support in Intelligent Autonomous Cruise Control. Technical Report LiTH-IDA-R-94-26, Department of Computer and Information Science, Linköping University, Sweden. Accepted to Intelligent Vehicles Symposium'94, Paris, France, October 24-26, 1994. (bibtex),
Abstract: The next-generation cars will be furnished with a multitude of advanced electronic equipment to enhance safety, increase driving comfort, improve economy and decrease environmental effects. Examples of devices to this end are autonomous intelligent cruise control (AICC), route guidance systems, and road/tyre friction estimation systems. Because these support systems generate a lot of data, the amount of information potentially available to the driver is very large, and sometimes contains even conflicting messages. In such situation there is an immanent danger of overloading the driver's perceptual and reactive capabilities. Clearly, there is a strong need for systematic handling of the output to the driver from different subsystems in the car, in order to guarantee that the driver gets the relevant information at the right time. This task is complicated by a number of circumstances, for instance: 1. Output requests may come from many different sources (support systems) operating independently, or almost independently, without a coherent view of the information available in the whole system. 2. Information is time-dependent, so it might prove useless, or even dangerous, if presented to the driver at the wrong time. 3. The amount of information the driver can handle is not untimed nor static, but varies dynamically depending on, among other things, the traffic situation, the weather conditions and the kind of manoeuvre the driver is performing. 4. There may be several output channels available (for example displays, voice output, and haptic actuators) whose appropriateness may change dynamically. 5. Drivers may prefer some output channels to others, or may want to suppress some kinds of messages (e. g. speed excess messages). In this paper we describe a tentative design of the driver support system to be integrated with the Volvo demonstrator car for the AICC function. The design is based on the concept of a driver information unit (DIU) which is able to represent both the dynamics of the environment and the driver's workload and preferences. The purpose of the DIU is to arbitrate between different communication requests on the basis of the current driving situation and to present the information to the driver using the most appropriate medium. The DIU is also able to filter the information according to the driver's expressed preferences. So far, the DIU builds and maintains a limited model of the environment from available sensor data and output from the support systems. It does not, however, predict or plan in advance what might happen, but the system design permits such services to be added, if required.
Orsborn, K. (1994). Applying Next Generation Object-Oriented DBMS to Finite Element Analysis. Technical Report LiTH-IDA-R-94-16, Department of Computer and Information Science, Linköping University, Sweden. Accepted to The 1st International Conference on Applications of Databases (ADB-94), Vadstena, Sweden, June 21-23, 1994. (bibtex),
Abstract: Scientific and engineering database applications put new requirements on database management systems that is usually not associated with traditional administrative database applications. These new database applications include fi nite element analysis (FEA) for computational mechanics and usually have a high level of complexity of both data and algorithms, as well as high volume of data and high requirements on execution efficiency. This paper shows how next gen eration object-oriented database technology that includes a relationally complete and extensible object-oriented query language can be used to model and manage FEA. The technology allows the design of domain models that represent applica tion-oriented conceptual models of data and operators. An initial integration of a main-memory object-relational database management system with a state-of-the- art FEA program is presented. The FEA program integrates the complete FEA process and is controlled completely through a graphical user interface. Examples are included of the conceptual model and its manipulation along with some initial performance measures. It is shown that the integrated system provides competi tive performance and is a promising alternative for design and implementation of future FEA software.
Padgham, L. and Lambrix, P. (1994). A Framework for Part-of Hierarchies in Terminological Logics. Technical Report LiTH-IDA-R-94-30, Department of Computer and Information Science, Linköping University, Sweden. Accepted to Principles of Knowledge Representation and Reasoning, Proceedings of the Fourth International Conference, Eds. Doyle, Sandewall, Torasso, pages:485-496 Bonn, Germany, May 24-27, 1994. (bibtex),
Abstract: There is a growing recognition that part-whole hierarchies are a very general form of representation, widely used by humans in commonsense reasoning. This paper develops a terminological logic, and related inference mechanisms for representing and reasoning about composite concepts and individuals. A basic terminological logic language is extended with constructs for describing composite concepts in terms of their parts and the relationships between them. A part-of hierarchy is defined, based on the relationship of compositional inclusion. This part-of hierarchy is analogous to, but different from, the "is-a" hierarchy. Compositional inferencing is defined as a process which infers the existence of a whole, based on the existence of the required parts, where the parts are in the necessary relationship to each other. Three stable states are defined with respect to compositional inferencing - compositional extensions, credulous compositional extensions and skeptical compositional conclusions. This framework significantly enhances and is complementary to, knowledge representation and reasoning based on is-a hierarchies.
Padgham, L. and Löwgren, J. (1994). A User Interface Management Approach for Object-Oriented Database Applications. Technical Report LiTH-IDA-R-94-33, Department of Computer and Information Science, Linköping University, Sweden. Accepted to Journal of Systems and Software. (bibtex),
Abstract: This paper discusses the development and management of object-oriented database applications using an approach where the user interface management is abstracted out from the underlying database, but nevertheless encapsulated in general purpose software - a user interface management module. We identify a list of requirement that this application domain introduces and then present the LINCKS object-oriented database system and the UIMS which was designed to meet these requirements. After introducing the architecture of the system, we illustrate by means of an example how an application is built and executed. We finally discuss our approach and identify several features stemming from the specialization of the UIMS to the area of object-oriented databases. These features include multiple views of application objects and encapsulated runtime behavior on the task level. Our conclusion is that the design of specialized UIMS for different application domains is a valuable alternative to the maximally general UIMS approach.
Padgham, L. and Zhang, T. (1994). A Terminological Logic with Defaults: A Definition and an Application. Technical Report LiTH-IDA-R-94-32, Department of Computer and Information Science, Linköping University, Sweden. Accepted to Proceedings of the 13th International JOINT Conference on Artificial Intelligence, pages 662-668 Chambe'ry, France, July 29 - September 3, 1993. (bibtex),
Abstract: In this paper we present a terminological language which includes defaults, and a definition of default subsumption based on the notion of skeptical inheritance in default reasoning. Except for the inclusion of defaults the language is limited when compared to most terminological logics. However defaults are a necessary construct in many applications and we suggest that the language presented here is a useful tradeoff between different types of expressivity. We present an algorithm for classifying new concepts into the default hierarchy representing the taxonomy, and in addition an algorithm for what we call default classification, suitable for interactive reasoning about individuals. We describe a diagnosis application which has been implemented using this language and reasoning mechanisms. We present an evaluation of the diagnosis application on the basis of comparison with 63 patient protocols. We conclude that the language presented is in fact adequate for the application presented here and hypothesize that it is interesting for a significant group of applications.
Peng, Z. (1994). Digital System Simulation with VHDL in a High-Level Synthesis System. Technical Report LiTH-IDA-R-94-02, Department of Computer and Information Science, Linköping University, Sweden. Published in Microprocessing and Microprogramming, the EUROMICRO Journal Vol 35, 1992. (bibtex),
Abstract: This paper presents the use of VHDL to simulate the intermediate design representation in a high-level synthesis system. The design representation is captured by an extended time Petri net notation and is used throughout the synthesis process. We have developed an algorithm to convert the design representation into a VHDL description. As a result, digital system designs can be simulatedtogether with the behavioral models of the primitive register-transfer level components which are also described in VHDL. The main feature of our approach is that the intermediate results (as well as the final results) of the high-level synthesis process can be simulated at any time and the simulation results can be used to guide the synthesis process.
Peng, Z. and Kuchcinski, K. (1994). An Algorithm for Partitioning of Application Specific Systems. Technical Report LiTH-IDA-R-94-01, Department of Computer and Information Science, Linköping University, Sweden. Published in Proceedings of the European Conference on Design Automation EDAC'93, Paris, France, February 22-25, 1993. (bibtex),
Abstract: This paper presents a simulated-annealing based algorithm to partition an application specific system into a set of modules. The role of partitioning is to discover the structure implicit in the functional specification of the system so as to guide high level synthesis decisions in a design environment for digital systems consisting of hardware parts and possibly software components. The partitioning algorithm can also be used to partition the final or intermediate results of a high-level synthesis process into several physical blocks. Experimental results show that our approach produces better register-transfer designs with less global communications.
Pettersson, K. (1994). Consequences of an IRM-based System Development - Experiences from a Case Study. Technical Report LiTH-IDA-R-94-05, Department of Computer and Information Science, Linköping University, Sweden. Accepted to the 16th Information Systems Research Seminar in Scandinavia, Copenhagen, Denmark, August 7-10, 1993. (bibtex),
Abstract: Information Resource Management (IRM) is an information system perspective and approach, which is being applied by some organizations to structure their information systems and design process. A case study, from which this paper is a result, has been performed at a company where the IRM-strategy is used. Since the IRM-strategy is formulated in a theoretical, ideal-typical way it has to be translated into practicality when realized. This paper addresses the following main issue: When applying IRM-principles in information system design, what kind of effects will these have on information systems, users and the organization?
Pettersson, K. (1994). IRM på försäkringsbolag - en fallstudie om strukturering av informationssystem. Technical Report LiTH-IDA-R-94-18, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: No abstract available
Pettersson, K. (1994). Några problem vid verksamhetsbaserad systemstrukturering. Erfarenheter från tre fallstudier.. Technical Report LiTH-IDA-R-94-49, Department of Computer and Information Science, Linköping University, Sweden. Föredrag presenterat på LISS 94, Linköpings universitet, Linköping, 20 april 1994. (bibtex),
Abstract: No abstract available
Pettersson, K. (1994). VBS i industriföretag - en fallstudie om strukturering av informationssystem. Technical Report LiTH-IDA-R-94-19, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: No abstract available
Pettersson, K. and Goldkuhl, G. (1994). A Comparison between two Strategies for Information Systems Architectures. Technical Report LiTH-IDA-R-94-08, Department of Computer and Information Science, Linköping University, Sweden. Accepted to the " Sundsvall 42" , Sundsvall, Sweden, October 19-21, 1993. (bibtex),
Abstract: No abstract available
Pettersson, M. (1994). RML - A New Language and Implementation for Natural Semantics. Technical Report LiTH-IDA-R-94-25, Department of Computer and Information Science, Linköping University, Sweden. Presented at the International Conference on Programming Language Implementation and Logic Programming (PLILP'94), Madrid, September 14-16, 1994. (bibtex),
Abstract: RML is a programming language intended for the implementation of Natural Semantics specifications. The basic procedural elements are relations: many-to-many mappings defined by a number of axioms or inference rules. It has control flow, logical variables and (explicit) unification as in Prolog; from ML it borrows a polymorphic type system, data structures, and pattern matching; a facility for separately-compilable modules also exists. A simple prototype compiler, based on translating RML to Continuation-Passing Style and then to C, has been implemented. Benchmarks indicate that this compiler generates code that is several orders of magnitude faster than Typol, and two times faster than standard Prolog compilers.
Röstlinger, A. (1994). STYRKEANALYS Ett arbetssätt för att tillvarata positiva aspekter i verksamheten. Technical Report LiTH-IDA-R-94-24, Department of Computer and Information Science, Linköping University, Sweden. Föredrag presenterat på VITS Höstseminarium, 28-29 sep 1993, Institutionen för datavetenskap, Linköpings universitet. (bibtex),
Abstract: Vid förändring av verksamheter är det väsentligt att analysera problem i syfte att reducera problemen i verksamheten. Men detta är inte tillräckligt. Det är också väsentligt att analysera styrkan i verksamheten, så att denna kan behållas och eventuellt vidareutvecklas. Om man inte fokuserar på styrkan, finns risker för att man skapar nya problem genom att förändra bort det som tidigare fungerade bra i verksamheten.
Röstlinger, A. (1994). Att tillvarata styrkan i gjorda IT-investeringar.. Technical Report LiTH-IDA-R-94-54, Department of Computer and Information Science, Linköping University, Sweden. Föredrag presenterat på Sundsvall 42, Sundsvall, 18-20 oktober 1994. (bibtex),
Abstract: No abstract available
Sandahl, K. (1994). Transferring Knowledge from Active Expert to End-user Environment. Technical Report LiTH-IDA-R-94-34, Department of Computer and Information Science, Linköping University, Sweden. Accepted to Knowledge Acquisition, vol 6, no 1, pages 1-22. (bibtex),
Abstract: An Active Expert methodology towards knowledge acquisition is proposed. Briefly this methodology implies that the expert should take as active a part as possible in the creation of the knowledge base. The knowledge engineer should act more like a teacher of knowledge structuring, as a tool designer and as a catalyst in the dialogue between the expert and the end-users. By doing so, many of the well-known problems with inter-human conflicts, knowledge engineer filtering, expert and end-user acceptance and maintenance could be reduced. The methodology has been developed during a 10-year period with three practical projects and a close cooperation with research in tool-based knowledge acquisition as the main empirical material. A major part of the paper is devoted to a description of the Active Expert methodology divided into 10 phases. Each phase is exemplified with material from practical projects.
Sandahl, K., Eriksson, H., and Österlund, B. (1994). Tool-Based Knowledge Management and Distribution of Knowledge to Customers' End-User in a Biochemical Domain. Technical Report LiTH-IDA-R-94-35, Department of Computer and Information Science, Linköping University, Sweden. Accepted to The International Symposium on the Management of Industrial and Corporate Knowledge, Compi\x8f gne, France, October 26-27, 1994. (bibtex),
Abstract: Knowledge Management understood as the ability to store, distribute and utilize the human knowledge being produced and consumed in an organization is the topic of this paper. Due to the large number of complex problems that arise when computer-based Knowledge Management is introduced in an organization, a cooperation between industrial development and academic research is necessary to advance the field. Through a series of different implementation efforts, Pharmacia Biotech AB has now reached a stage where a large in-house knowledge base is utilized to produce knowledge-based systems which give added value both to control software of physical bio-chemical equipment as well as handbooks. In parallel, the knowledge-linker research project has focused the issue of how software supporting the Knowledge Management organization can be realized. A partial implementation in a problem obtained at Pharmacia has been completed. The architecture, is centered around a knowledge-acquisition tool used directly by experts to document their experience. This tool is in turn supported by a meta-tool, which aids the knowledge engineer in the creation and maintenance of several knowledge-acquisition tools in different generic domains. A key issue in this research has been to find a knowledge representation which allow a flexible utilization by the end-users including problem-solving, information retrieval and intelligent tutori
Sandewall, E. (1994). Features and Fluents. A Systematic Approach to the Representation of Knowledge about Dynamical Systems. Final Review Version. Technical Report LiTH-IDA-R-94-15, Department of Computer and Information Science, Linköping University, Sweden. To be published by Oxford University Press. (bibtex),
Abstract: The report proposes and uses a systematic methodology for the presentation, analysis, and comparison of logics of action and change, in particular for logics that deal with the "frame problem". The methodology is characterized by three major aspects: - The use of an underlying semantics for characterizing systems with in ertia (temporal persistence). - The use of an ontological taxonomy which is strictly defined in terms of the underlying semantics, and which characterizes classes of dynamical systems with specific restrictions on them. - Formally proven assessments of the range of applicability of various (non-monotonic) entailment criteria. The main results in the report are assessment results for a number of logics of time and action, including both logics that have been proposed before and logics defined here. The report is a second review version of a forthcoming book on the logic of reasoning about action and time, and on various aspects of the frame problem. The report corresponds to the first part of the intended book.
Sandewall, E. (1994). The Range of Applicability of some Nonmonotonic Logics for Strict Inertia. Technical Report LiTH-IDA-R-94-14, Department of Computer and Information Science, Linköping University, Sweden. To appear in the Journal of Logic and Computation. (bibtex),
Abstract: We present assessments for a number of previously proposed theories of action and change as well as some new ones. Each assessment identifies a class of scenarios for temporal reasoning where the theory is guaranteed to obtain the correct results. For some of the theories we have also obtained upper-bound results on the range of correct applicability. The theories and the their validation criteria use a logic with explicit integer time, and has been generalized to linear and branching metric time. The assessments show how the correctness of each theory depends on factors such as whether actions are deterministic, whether scenarios involve prediction only, or what is the behavior of each type of action within its execution period. The paper describes equally the methodology that has been used for obtaining the assessments, and the assessments themselves.
Save'n, B. (1994). Beslutsstöd och simulering i verkstadsföretag - En sammanfattning av två enkätstudier. Technical Report LiTH-IDA-R-94-17, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: No abstract available
Sköld, M. and Risch, T. (1994). Compiling Active Object-Relational Rule Conditions into Partially Diffirentiated Relations. Technical Report LiTH-IDA-R-94-10, Department of Computer and Information Science, Linköping University, Sweden. Presented at the Dagstuhl-Seminar on Active Databases, Schloss, Dagstuhl, Germany, March 1994. (bibtex),
Abstract: We present ongoing work on tightly integrating active rules with a next generation object-oriented(OO) database system having transactions and a relationally complete OO query language. The rules are defined as Condition Action (CA) pairs that can be parameterized, overloaded, and generic. The condition part of a rule is defined as a declarative OO query and the action as procedural statements. Rule condition monitoring must be efficient with respect to processor time and memory utilization. To meet these goals, a number of techniques have been developed for compilation and evaluation of rule conditions. The techniques permit efficient of deferred rules, i.e. rules whose executions are deferred until a check phase usually occurring when a transaction is committed. The techniques do not assume permanent materializations, but this can be added as an optimization option. A rule compiler generates screener predicates and partially differentiated relations. Screener predicates screen physical events as they are logged in order to efficiently capture those events that influence activated rules. Physical events that pass through screeners are accumulated. At the check phase the accumulated changes are incrementally propagated to the relations that they affect in order to determine whether some rule condition has changed. Partial differentiation is defined formally as a way for the rule compiler to automatically generate partially differentiated relations The technique assumes that the number of updates in a transaction is small and therefore usually onlysome of the partially differentiated relations need to be propagated. Cost based optimization techniques are utilized for both screener predicates and partially differentiated relations. The paper introduces a calculus for incremental evaluation based on partial differentiation. It also presents a propagation algorithm based on the calculus.
Söderman, U. (1994). Conceptual Modelling of Physical Systems - a Frame od Reference. Technical Report LiTH-IDA-R-94-39, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: The construction of models of physical systems that are adequate for effective model based reasoning is generally recognized as a difficult task. The use of computer aided modelling systems, which provide high-level support and enhance the modelling task, is therefore most attractive. In the Artificiell Intelligence subfield of Qualitative Physics, a number of approaches to representation, automatic selection and composition of models have been proposed over the years. However, these approaches stem from research governed by different goals and motivations and they tend, therefore, to provide their own sets of ontological primitives, their own representation schemes, creation and selection processes, and different illustrating examples. As a consequence it can often be hard to grasp what the proposed approaches have in common and what the differences are.In this paper we present a frame of reference for physical systems modelling. It is intended to facilitate and support future discussions and comparisons of other approaches. In addition, it provides good insight into modelling and may therefore also serve as a useful reference in the development of computer aided modelling systems. The frame takes the form of an approach to modelling in its own right and is referred to as the reference approach.In the reference approach, modelling starts with a real world system, or a design of it, and finishes with a model for prediction of the system's behaviour. In the reference approach we emphasize the conceptual side of modelling and deemphasize the numerical side. The principal contents of the reference approach are: An ontology incorporating a small and well defined set of generic ontological primitives; a network model having a clear syntax and semantics; guidelines for the mathematical characterization; a clear notion of causality; and a causality assignment procedure.
Söderman, U. and and, J.-E. S. (1994). Switched Bond Graphs: Towards Systematic Composition of Computational Models. Accepetd to The International Conference on Bond Graph Modeling and Simulation ICBGM95, Las Vegas, USA, January 1995. Technical Report LiTH-IDA-R-94-38, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: In classical bond graph modelling, a computational model is systematically composed from the parts without having to introduce local or global patches. Unfortunately this has not yet been fully carried over to switched bond graphs, i.e. bond graphs employing the ideal switch concept. The focus of this paper is on the systematic composition of the discrete mode transitions. To this end we provide a mathematical structure for the composed computational model and a procedural composition operator. We also outline an algorithm to localize and adjust the composed system in those cases where the composition operator fails. An important concept in this treatment is the generalization of primitive switches to multiport switch fields.
Söderman, U., Top, J., and Strömberg, J.-E. (1994). The Conceptual Side of Mode Switching. Technical Report LiTH-IDA-R-94-07, Department of Computer and Information Science, Linköping University, Sweden. Accepted to 1993, IEEE International Conference on Systems, Man and Cybernetics, Le Touquet, France, October 1993. (bibtex),
Abstract: For continuous dynamic systems there are many powerful methods for modelling. However, when dealing with systems undergoing abrupt behavioural changes, i.e. mode switching systems, the picture suddenly is changed. We here claim that the reason for this is that mode switching traditionally is treated by mathematical and/or logical solutions only. That is, at the wrong level of abstraction. We present several arguments supporting this view, and finally present our solution to this problem: the ideal switch concept.
Söderman, U., Top, J., and Strömberg, J. E. (1994). Modelling Physical Systems with Changing Structure. Technical Report LiTH-IDA-R-94-06, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: Causality plays an important role in essentially any aspect of reasoning about physical systems. However, causal directedness is problematic when the physical structure, i.e. the interaction between subsystems changes. This is due to the fact that causality is a global property. This problem can in principle be solved by specifying acausal models and to derive causality afterwards for the complete model. This is possible because physical systems are connected through bilateral signal flows, with no a priori fixed direction.Sofar, there has been no systematic and efficient way to represent acausal models of structures that undergo change. This would be an important feature of automated modelling and reasoning systems. In this paper we propose the definition of an ideal, generic switching element solving exactly this representation problem. The definition also adds a new ontological primitive to the bond graph language, though the general definition is not restricted to any specific modelling approach. Furthermore, the clear and explicit bond graph method to derive the overall causality can be reused unaltered. Several examples are presented to illustrate our approach.
Stefan Cronholm, G. G. (1994). Meanings and Motives of Method Customizations in CASE Environments - Observations and categorizations from an empirical study.. Technical Report LiTH-IDA-R-94-51, Department of Computer and Information Science, Linköping University, Sweden. Accepted to the 5th European Workshop on next Generation of CASE Tools, Utrecht, the Netherlands, June 6-7, 1994. (bibtex),
Abstract: No abstract available
Strömbäck, L. (1994). FLUF: A Flexible Unification Formalism - Syntax and Semantics. Technical Report LiTH-IDA-R-94-13, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: FLUF: A FLexible Unification Formalism - Syntax and Semantics Lenas Strömbäck Abstract The report presents the FLexible Unification Formalism (FLUF) as our solution of a flexible unification-based formalism\x11for natural language processing. For this formalism we give both a declarative and an operational semantics based on the theory for term rewriting systems and narrowing. We also give some results about soundness and completeness.
Strömbäck, L. (1994). FLUF: A Flexible Unification Formalism - the Idea. The short version accepted to the 15th International Conference on Computational Linguistics, Kyoto, Japan, 5-9 Augusti 1994. Technical Report LiTH-IDA-R-94-12, Department of Computer and Information Science, Linköping University, Sweden. (bibtex),
Abstract: FLUF: A FLexible Unification Formalism - the Idea Lena Strömbäck Abstract In this report we focus on flexibility as an important property for a unification-based formalism within natural language processing. We motivate the need for a flexible formalism by observing that the extensions defined for unification-based formalism are numerous. Moreover, it does not seem possible to define a formalism which include all these extensions and variants of extensions why we instead suggest a flexible formalism which can be adjusted to the needs of the user as the solution. We present the main features of FLUF as our solution to a flexible formalism. We also demonstrate how FLUF can be used by expressing some different extensions proposed for unification-based formalisms in it and by comparing it to some other unification-based formalisms.
Strömberg, J.-E., Söderman, U., and Top, J. (1994). Conceptual Modelling of Hybrid Systems. Technical Report LiTH-IDA-R-94-40, Department of Computer and Information Science, Linköping University, Sweden. Accepted to The European Simulation Conference ESM'94 Barcelona, Spain, June 1994. (bibtex),
Abstract: For continuous physical systems there are many powerful methods for modelling, one of them being the conceptual modelling technique as supported by the bond graph language. However, when dealing with systems undergoing abrupt behavioural changes, i.e. mode switching or hybrid systems, the picture is quite different. The reason for this is that mode switching traditionally is treated by means of mathematical and logical concepts only instead of by more physically oriented concepts. This implies adhoc constructs and limited possibilities for automation. It is our claim that a proper concept at the physical level effectively can eliminate this modelling bottleneck. We present several arguments supporting this view, and present our solution: the ideal switch concept. An example is provided to show its practical application