| 1. |
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| 2. |
- Bigun, Josef
(författare)
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Circular Symmetry Models in Image Processing
- 1986
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- New methods for feature extraction based on the spectral properties of local neighbourhoods is presented. The spectral behaviour of the neighbourhoods is investigated in the spatial domain using the Parseval relation applied to partial derivative pictures. Two types of such properties are considered for circular symmetric and linear symmetric neighbourhoods. These two properties are the existence of point concentration and line concentration in the spectra. For the circular symmetry investigation a new basis function set is introduced. To obtain a spectrum in the terms of these basis function sets, a scalar product is introduced for circular neighbourhoods. The same is carried out for linear symmetry spectra using the well-known basis set and the scalar product consisting of cosines and ?2(Ω) scalar product. Confidence parameters are introduced to measure the significance of the extracted features. These are basically different types of variance measures and they are shown to be specific for the desired information: The existence of point concentration or line concentration in the spectra of the local neighbourhoods.
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| 3. |
- Bilos, Rober
(författare)
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Incremental scanning and token-based editing
- 1987
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A primary goal with this thesis work has been to investigate the consequences of a token-based program representation. Among the results which are presented here are an incremental scanning algorithm together with a token-based syntax sensitive editing approach for program editing.The design and implementation of an incremental scanner and a practically useful syntax-sensitive editor is described in some detail. The language independent incremental scanner converts textual edit operations to corresponding operations on the token sequence. For example, user input is converted to tokens as it is typed in. This editor design makes it possible to edit programs with almost the same flexibility as with a conventional text editor and also provides some features offered by a syntax-directed editor, such as template instantiation, automatic indentation and prettyprinting, lexical and syntactic error handling.We have found that a program represented as a token sequence can on the average be represented in less than half the storage space required for a program in text form. Also, interactive syntax checking is speeded up since rescanning is not needed.The current implementation, called TOSSED - Token-based Syntax Sensitive Editor, supports editing and development of programs written in Pascal. The user is guaranteed a lexically and syntactically correct program on exit from the editor, which avoids many unnecessary compilations. The scanner, parser, prettyprinter, and syntactic error recovery are table-driven and language independent template specification is supported. Thus, editors supporting other languages can be generated.
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| 4. |
- Block, Hans
(författare)
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Sport-sort : sorting algorithms and sport tournaments
- 1987
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Arrange a really short, thrilling and fair tournament! Execute parallel sorting in a machine of a new architecture! The author shows how these problems are connected. He designs several new tournament schemes, and analyses them both in theory and in extensive simulations. He uses only elementary mathematical and statistical methods. The results are much better than previous ones, and close to the theoretical limit. Now personal computers can be used to arrange tournaments which give the complete ranking list of several thousands of participants within only 20 - 30 rounds.
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| 5. |
- Bonnier, Staffan
(författare)
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Horn clause logic with external procedures : towards a theoretical framework
- 1989
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Horn clause logic has certain properties which limit its usefulness as a programming language. In this thesis we concentrate on three such limitations: (1) Horn clause logic is not intended for the implementation of algorithms. Thus, if a problem has an efficient algorithmic solution it may be difficult to express this within the Horn clause formalism. (2) To work with a predefined structure like integer arithmetic, one has to axiomatize it by a Horn clause program. Thus functions of the structure are to be represented as predicates of the program. (3) Instead of re-implement existing software modules, it is clearly better to re-use them. To this end, a support for combining Horn clause logic with other programming languages is needed.When extending the Horn clause formalism, there is always a trade-off between general applicability and purity of the resulting system. There have been many suggestions for solving some of problems (1) to (3). Most of them use one of the following strategies: (a) To allow new operational features, such as access to low-level constructs of other languages. (b) To introduce new language constructs, and to support them by a clean declarative semantics and a complete operational semantics.In this thesis a solution to problems (1) to (3) is suggested. It combines the strategies of (a) and (b) by limiting their generality: We allow Horn clause programs to call procedures written in arbitrary languages. It is assumed however that these procedures are either functional or relational. The functional procedures yield a ground term as output whenever given ground terms as input. Similarly, the relational procedures either succeed or fail whenever applied to ground terms. Under these assumptions the resulting language has a clean declarative semantics.For the operational semantics, an extended but incomplete unification algorithm, called S-unify is developed. By using properties of this algorithm we characterize classes of goals for which our interpreter is complete. It is also formally proved that (a slightly extended version of) S-unify is as complete as possible under the adopted assumptions.
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| 6. |
- Bårman, Håkan
(författare)
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Curvature Estimation and Description
- 1989
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents a new method for detection and estimation of curvature. The algorithm is implemented in the hierarchical feature pyramid proposed in the GOP concept. Curvature is handled at the second level of the pyramid with a vector field description of the orientation of the image as input. This complex image is convolved with typically eight filters. The filter responses are combined into a description of curvature direction, curvature magnitude and curvature/linearity ratio. The procedure resembles in many ways the algorithms for the first level of the feature pyramid and seems to be a natural extension of these. The method is easy to implement and the tests made show that it performs well and can handle noisy conditions. Some comparisons with other algorithms have been carried out, and the results indicate that the methodology presented in this paper has a number of important advantages over other methods.
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| 7. |
- Bäckström, Christer, 1962-
(författare)
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Reasoning about interdependent actions
- 1988
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis consists of two papers on different but related topics.The first paper is concerned with the use of logic as a tool to model mechanical assembly processes. A restricted 2+-dimensional world is introduced and although this world is considerably simpler than a 3-dimensional one, it is powerful enough to capture most of the interesting geometrical problems arising in assembly processes. The geometry of this 2+-dimensional world is axiomatized in first order logic. A basic set of assembly operations are identified and these operations are expressed in a variant of dynamic logic which is modified to attack the frame problem.The second paper presents a formalism for reasoning about systems of sequential and parallel actions that may interfere or interact with each other. All synchronization of actions is implicit in the definitions of the actions and no explicit dependency information exists. The concept of action hierarchies is defined, and the couplings between the different abstraction levels are implicit in the action definitions. The hierarchies can be used both top-down and bottom-up and thus support both planning and plan recognition in a more general way than is usual.
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| 8. |
- Fagerström, Johan
(författare)
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Simulation and evaluation of an architecture based on asynchronous processes
- 1985
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Much research today is devoted to finding new and improved computer architectures in which parallel computations can be performed, the goal being an exploitation of the natural parallelism inherent in many problem descriptions. This thesis describes a register level simulator for a family of architectures based on asynchronous processes. An important aspect of this class of architectures is its modularity. Within the architecture, we hope to avoid the problem of dynamically binding every operation as in dataflow machines. A silicon compiler can use the modularity of descriptions to perform various optimizations on instances of the architecture. The simulator is written in a language called Occam, in which parallel execution at the statement level can be expressed. A short description of the language is given and some of the issues of designing, testing and maintaining concurrent programs are discussed. The added complexity of parallelism especially makes the debugging phase very difficult.
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| 9. |
- Gunnarsson, Svante
(författare)
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On the Mean Square Error of Transfer Function Estimates with Applications to Control
- 1986
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this report we study the mean square error of transfer function estimates obtained by identification. The model quality is related to the use of models in regulator design, and the properties of affecting the bias part of the mean square error, both in fixed parameter control and adaptive control.We also study the variance part of the mean square error for transfer function estimates obtained by recursive identification. In the report we derive expressions for the variance as a function of the step length of the identification method, the input spectrum, the variations of the true system and the model order. These expressions are verified and utilized in simulations.
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| 10. |
- Haglund, Leif
(författare)
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Hierarchical Scale Analysis of Images Using Phase Description
- 1989
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Scale analysis and description has over the last years become one of the major research field!The thesis describes a new algorithm which detects in what scale an event appears and also in what scale it disappears. In this way the scale space is subdivided into a number of intervals. Within each scale interval a consistency check is performed to get the certainty of the detection. It will be shown that using a three-dimensional phase representation of image data, it is possible to do both the subdivision and the consistency check in a simple manner. The scale levels between different events are detected when a certain dot product becomes negative and the consistency will be a vector summation between these scales. The specific levels where a split of scale space occurs will, of course, be contextually dependent and there will also be different numbers of levels in different parts of the images. Finally an application of size description of this information will be described.
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