| 1. |
- Eriksson, Håkan, et al.
(författare)
-
A robust correlation receiver for distance estimation
- 1994
-
Ingår i: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control. - New York : Institute of Electrical and Electronics Engineers (IEEE). - 0885-3010 .- 1525-8955. ; 41:5, s. 596-603
-
Tidskriftsartikel (refereegranskat)abstract
- Many methods for distance estimation, such as the ultrasonic pulse-echo method, involve the estimation of a time-of-flight (TOF). In this paper, a signal model is developed that, apart from the TOF, accounts for an unknown, linear frequency dependent distortion as well as for additive noise. We derive a TOF estimator for this model based on the criteria of maximum likelihood. The resulting receiver can be seen as an extension or generalization of the well known cross-correlation, or "matched filter", estimator described, e.g., by Nilsson. The novel receiver is found to be more robust against unknown pulse shape distortion than the cross-correlation estimator, giving less biased TOF estimates. Also, bias versus noise sensitivity can be controlled by proper model order selection
|
|
| 2. |
- Nordebo, Sven, et al.
(författare)
-
An Adaptive Microphone Array Employing Calibration Signals Recorded On-Site
- 1994
-
Konferensbidrag (refereegranskat)abstract
- This paper presents an adaptive microphone array, which facilitates a simple built-in calibration to the environment and the electronic equipment used. The method is well-suited for speech enhancement in handsfree mobile telephones as well as for speech enhancement in speech recognition devices.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Arvidsson, Åke
(författare)
-
Management of Reconfigurable Virtual Path Networks
- 1994
-
Ingår i: The Fundamental Role of Teletraffic in the Evolution of Telecommunication Networks. - Amsterdam : Elsevier. - 9920106445 ; , s. 931-940
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- We study dynamically rearrangable end-to-end transport networks by means of SDH/SONET and/or ATM virtual paths. The concept and its advantages are brie y reviewed and we propose a new algorithm for designing such networks. Our algorithm provides integer solutions, handles non-linear equivalent bandwidths, finds its own paths, and allows for an arbitrary design optimisation criterion. It is found to perform equal to or better than an earlier, comparable though more restricted, algorithm. We also put forward a strategy for managing virtual paths in real time. It consists of a repeated cycle of on-line measurement of offered traffics followed by the design and implementation of a new virtual path network. Methods and parameters for traffic measurements and network updating frequency are studied and optimised. Applying the strategy to rearrangeable networks subject to variable traffics in a simulator, we discover considerable gains and a robustness in our parameter settings.
|
|
| 7. |
- Arvidsson, Åke
(författare)
-
Real Time Management of Virtual Paths
- 1994
-
Konferensbidrag (refereegranskat)abstract
- We propose a simple and robust automatic strat- egy for managing SDH/SONET and/or ATM virtual paths in real time to handle slow traffic variations. It consists of on-line measurements of offered traffics followed by the design and possi- ble implementation of a new virtual path network in a repeated cycle. Methods and parameters for traffic measurements and network updating are studied and optimised to achieve maximal traffic carrying capability at minimal cost. Applying our strat- egy to networks subject to partially unknown, variable traffics we discover a considerable adaptivity, large savings in transmis- sion capacity, and a performance far better than achieved by deterministic management.
|
|
| 8. |
- Bosch, Jan
(författare)
-
Paradigm, Language Model and Method
- 1994
-
Rapport (övrigt vetenskapligt/konstnärligt)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.
|
|
| 9. |
- Bosch, Jan
(författare)
-
Parser Delegation : An Object-Oriented Approach to Parsing
- 1994
-
Rapport (övrigt vetenskapligt/konstnärligt)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.
|
|
| 10. |
- Bosch, Jan
(författare)
-
Relations as Object Model Components
- 1994
-
Rapport (övrigt vetenskapligt/konstnärligt)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.
|
|
