| 11. |
- Arvidsson, Åke
(author)
-
Strategies for Dynamic Network Management
- 1993
-
Conference paper (peer-reviewed)abstract
- We study management of transport networks based on virtual paths, i.e. rearrangable end-to-end transport network \highways". Among its main advantages are found cost savings, network op- eration simplification and enhanced network management capabilities. Virtual paths networks are readily implemented in any network using the synchronous digital hierarchy and/or the asyn- chronous transfer mode. Algorithms for virtual path designs are reviewed and found to have a few shortcomings. A new algorithm is therefore proposed and it is found to compare favourably with the algorithm providing the most similar features. Applying the proposed algorithm to a large number of networks, we discuss operational con- siderations associated with reconfigurable networks and investigate simple traffic estimation pro- cedures and their performance in this context. Finally, the choice of reconfiguration parameters such as updating frequency, and the impact of network design time are examined.
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| 12. |
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| 13. |
- Bosch, Jan
(author)
-
Paradigm, Language Model and Method
- 1994
-
Reports (other academic/artistic)abstract
- Programming languages and software engineering methods are highly related in that both are images of an underlying paradigm. In this paper we investigate the role of the paradigm, the language model and the software development method and define requirements on each of the three concepts. Subsequently, we describe the {\em layered object model}, an extended object model which allows for first-class representation of relations between objects and constraints on the behaviour of an object, and discuss how it achieves {\em paradigm extensibility}, i.e. extensibility of the paradigm and the supporting language model.
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| 14. |
- Bosch, Jan
(author)
-
Parser Delegation : An Object-Oriented Approach to Parsing
- 1994
-
Reports (other academic/artistic)abstract
- Conventional grammar specification and parsing is generally done in a monolithic manner, i.e. the syntax and semantics of a grammar are specified in one large specification. Although this might be sufficient in static environments, a modular approach is required in situations where the syntax or semantics of a grammar specification are subject to frequent changes. The problems with monolithic grammars are related to (1) dealing with the complexity, (2) extensibility and (3) reusability. We propose the concept of {\em parser delegation} as a solution to these problems. Parser delegation allows one to modularise and reuse grammar specifications. To achieve this, the notion of a production rule is specialised into (1) overriding, (2) extending and (3) delegating production rule types. To experiment with parser delegation, we have developed D-yacc, a graphical tool for defining grammars. Parser delegation has been applied for constructing a translator for an experimental language and is currently applied in other domains.
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| 15. |
- Bosch, Jan
(author)
-
Relations as Object Model Components
- 1994
-
Reports (other academic/artistic)abstract
- Although object-oriented methods make extensive use of relations between objects, these relations, other than inheritance and part-of, can not directly be represented by the conventional object-oriented model. This means that relations which are identified during analysis and design have to be implemented on top of the object model, i.e. by using method code and message passing, rather than by expressing relations directly within in the model. It would be beneficial if the object-oriented model would support the specification of all relevant types of relations within the model, including application-domain specific relation types. Therefore, we propose a mechanism, implemented in LayOM -- an extended object model, that supports the specification of all types of relations between objects within the model as components of the object model. In addition, an approach for identifying and specifying application-domain relation types is presented.
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| 16. |
- Bosch, Jan
(author)
-
Software Artifacts as Autonomous Agents
- 1994
-
Reports (peer-reviewed)abstract
- In this paper, a number of problems of conventional automated software engineering support environments are described. These problems are related to the functional approach these environments take, the lack of initiative these systems exhibit and the causal connection gap between design information and the operational entity. As an alternative, we suggest an autonomous agent approach. Each artifact is modelled as an autonomous agent that is responsible for its own development. Artifacts are organised in specialisation hierarchies which can be traversed by agents. As a consequence, the methodology needs to be inverted, i.e. specified from the artifact's perspective rather than from the software engineer's perspective.
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| 17. |
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| 18. |
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| 19. |
- Claesson, Ingvar, et al.
(author)
-
A Multi-DSP implementation of a Broadband Adaptive Beamformer for use in a Hands-free Mobile Radio Telephone
- 1991
-
In: IEEE Transactions on Vehicular Technology. - New York : Institute of electrical and electronics engineers. - 0018-9545. ; 40:1, s. 194-202
-
Journal article (peer-reviewed)abstract
- An implementation of a broadband adaptive array on a multiprocessor digital signal processing (DSP) system for use in a hands-free mobile radio telephone is described. This implementation of a five-microphone adaptive Griffiths-Jim array can handle FIR filters with up to 128 taps behind each microphone at a sampling rate of 8 kHz. The filter structure makes it possible to combine an adaptive array with a noise canceler. The near-field problem has been solved by using focusing, a speech-controlled adaptive algorithm, and a short hourglass. Preliminary measurements indicate a considerable potential for this technique in hands-free mobile telephony. The array gives a 20-30-dB suppression of a broadband jammer covering 300-1100 Hz, even with three reflecting walls surrounding the microphone.
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| 20. |
- Claesson, Ingvar, et al.
(author)
-
A Spatial Filtering Approach to Robust Adaptive Beamforming
- 1992
-
In: IEEE Transactions on Antennas and Propagation. - New York : Institute of electrical and electronics engineers. - 0018-926X. ; 40:9, s. 1093-1096
-
Journal article (peer-reviewed)abstract
- This communication treats the problem of controlling the superresolution in adaptive beamformers. A straightforward method is presented that works for both narrow-band and broad-band arrays. The method is based on forming the blocking matrix in a general sidelobe canceller (GSC) structure using a spatial FIR filter. The suppression of this spatial filter and the implicit noise of the leaky (LMS) algorithm together determine the beamformer.
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