| 1. |
- Eriksson, Patric, et al.
(författare)
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A role for 'sensor simulation' and 'pre-emptive learning' in computer aided robotics
- 1995
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Ingår i: 26th International Symposium on Industrial Robots, Symposium Proceedings. - : Mechanical Engineering Publ.. - 1860580009 ; , s. 135-140
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Konferensbidrag (refereegranskat)abstract
- Sensor simulation in Computer Aided Robotics (CAR) can enhance the capabilities of such systems to enable off-line generation of programmes for sensor driven robots. However, such sensor simulation is not commonly supported in current computer aided robotic environments. A generic sensor object model for the simulation of sensors in graphical environments is described in this paper. Such a model can be used to simulate a variety of sensors, for example photoelectric, proximity and ultrasonic sensors. Tests results presented here show that this generic sensor model can be customised to emulate the characteristics of the real sensors. The preliminary findings from the first off-line trained mobile robot are presented. The results indicate that sensor simulation within CARs can be used to train robots to adapt to changing environments.
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| 2. |
- Bengtsson, Lars, 1963
(författare)
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Mikrodatorteknik
- 1995
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Första delen behandlar Microchips "Base-line"-kretsar och andra delen behandlar "Midrange"-kretsarna. De flesta funktioner belyses med konstruktionsexempel. Exempel och övningar är mycket hårdvarunära och boken behandlar konstruktion av mikrodatorer från grunden. Boken är avsedd för kurser i mikrodatorteknik på högskolan eller annan högre teknisk utbildning, men kan även användas som självstudiematerial eftersom de flesta exempel ges med detaljerade och verifierade lösningar av såväl hård- som mjukvaran. Tidigare erfarenhet av assemblerprogrammering är inte nödvändig men grundläggande kunskaper i digitalteknik förutsätts. Boken kan med fördel också läsas av rutinerade assemblerprogrammerare som vill veta hur prestanda hos de nya RISC-baserade PIC-controllerna står sig i konkurrensen med de mer etablerade enchipscontrollerna, t ex HC11 och 8751, som bygger på traditionell CISC-arkitektur.
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| 3. |
- Lindeberg, Tony, 1964-, et al.
(författare)
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Analysis of brain activation patterns using a 3-D scale-space primal sketch
- 1999
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Ingår i: Human Brain Mapping. - 1065-9471 .- 1097-0193. ; 7:3, s. 166-94
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Tidskriftsartikel (refereegranskat)abstract
- A fundamental problem in brain imaging concerns how to define functional areas consisting of neurons that are activated together as populations. We propose that this issue can be ideally addressed by a computer vision tool referred to as the scale-space primal sketch. This concept has the attractive properties that it allows for automatic and simultaneous extraction of the spatial extent and the significance of regions with locally high activity. In addition, a hierarchical nested tree structure of activated regions and subregions is obtained. The subject in this article is to show how the scale-space primal sketch can be used for automatic determination of the spatial extent and the significance of rCBF changes. Experiments show the result of applying this approach to functional PET data, including a preliminary comparison with two more traditional clustering techniques. Compared to previous approaches, the method overcomes the limitations of performing the analysis at a single scale or assuming specific models of the data.
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| 4. |
- Christiansson, Anna-Karin, 1947-, et al.
(författare)
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Mixed continuous/discrete-time output feedback H∞ control : A unified approach
- 1999
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Ingår i: European Control Conference, ECC 1999 - Conference Proceedings. - 9783952417355 ; , s. 4077-4082
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Konferensbidrag (refereegranskat)abstract
- A Riccati equation (RE) based solution to the H∞ optimal control problem for mixed continuous/discrete-time systems is presented. The results unify a number of recently penetrated H∞ control problems. In the infinite-horizon case a periodic behaviour is assumed, and it is shown how the related continuous RE with jumps can be replaced by an equivalent discrete periodic RE. A related algebraic RE, which involves the system behaviour during one period, then can be formulated and solved by standard methods. Typical applications are control of continuous-time or discrete-time periodic systems, as well as multirate and sampled-data control, including mixed continuous and sampled-data measurements. © 1999 EUCA.
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| 5. |
- Åkerman, S., et al.
(författare)
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Surface Model Generation and Segmentation of the Human Celebral Cortex for the Construction of Unfolded Cortical Maps
- 1996
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Ingår i: Proc. 2nd International Conference on Functional Mapping of the Human Brain. ; , s. S126-S126
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Konferensbidrag (refereegranskat)abstract
- Representing the shape of the human cerebral cortex arises as a basic subproblem in several areas of brain science, such as when describing the anatomy of the cortex and when relating functional measurements to cortical regions. Most current methods for building such representions of the cortical surface are either based on contours from two-dimensional cross sections or landmarks that have been obtained manually.In this article, we outline a methodology for semi-automatic contruction of a solely surface based representation of the human cerebral cortex in vivo for subsequent generation of (unfolded) two-dimensional brain maps.The method is based on input data in the form of three-dimensional NMR images, and comprises the following main steps:suppression of disturbing fine-scale structures by linear and non-linear scale-space techniques,generation of a triangulated surface representation based on either iso-surfaces or three-dimensional edge detection,division of the surface model into smaller segments based on differential invariants computed from the image data.When constructing an unfolded (flattened) surface representation, the instrinsic curvature of the cortex means that such a unfolding cannot be done without introducing distortions. To reduce this problem, we propose to cut the surface into smaller parts, where a ridge detector acts as guideline, and then unfold each patch individually, so as to obtain low distortions.Having a solely surface based representation of the cortex and expressing the image operations using multi-scale differential invariants in terms of scale-space derivatives as done in this work is a natural choice both in terms of conceptual and algorithmic simplicity. Moreover, explicitly handling the multi-scale nature of the data is necessary to obtain robust results.
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| 6. |
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| 7. |
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| 8. |
- Ujvari, Sandor, 1972-, et al.
(författare)
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Simulation and emulation of sensor systems for intelligent vehicles
- 1998
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Ingår i: Mechatronics '98. - : Pergamon Press. - 0080433391 ; , s. 385-390
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Konferensbidrag (refereegranskat)abstract
- Simulation of sensor systems for mobile robots are described in this paper. By simulation of smart sensor systems, the performance of semi-autonomous vehicles / mobile robots can be enhanced. Smart sensor systems used in the field of mobile robotics can utilise adaptive algorithms. e. g. artificial neural nets, fuzzy logic or hybrid variants of these systems. The development, training and evaluation of adaptive algorithms for sensor systems can be done within a virtual environment in which graphical models are built to simulate an intelligent vehicle, its sensors, and its environment. The virtual sensors are validated by comparing the characteristics of the virtual sensors with those of the real devices.
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| 9. |
- Jonsson, Erland, 1946, et al.
(författare)
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A quantitative model of the security intrusion process based on attacker behavior
- 1997
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Ingår i: IEEE Transactions on Software Engineering. - : Institute of Electrical and Electronics Engineers (IEEE). - 0098-5589 .- 1939-3520. ; 23:4, s. 235-245
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Tidskriftsartikel (refereegranskat)abstract
- This paper is based on a conceptual framework in which security can be split into two generic types of characteristics, behavioral and preventive. Here, preventive security denotes the system's ability to protect itself from external attacks. One way to describe the preventive security of a system is in terms of its interaction with the alleged attacker, i.e., by describing the intrusion process. To our knowledge, very little is done to model this process in quantitative terms. Therefore, based on empirical data collected from intrusion experiments, we have worked out a hypothesis on typical attacker behavior. The hypothesis suggests that the attacking process can be split into three phases: the learning phase, the standard attack phase, and the innovative attack phase. The probability for successful attacks during the learning and innovative phases is expected to be small, although for different reasons. During the standard attack phase it is expected to be considerably higher. The collected data indicates that the breaches during the standard attack phase are statistically equivalent and that the times between breaches are exponentially distributed. This would actually imply that traditional methods for reliability modeling could be applicable.
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| 10. |
- Lindeberg, Tony, 1964-
(författare)
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On the behaviour in scale-space of local extrema and blobs
- 1991
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Ingår i: Theory and Applications of Image Analysis. - : World Scientific. ; , s. 38-47, s. 8-17
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Bokkapitel (refereegranskat)abstract
- We apply elementary techniques from real analysis and singularity theory to derive analytical results for the behaviour in scale-space of critical points and related entities. The main results of the treatment comprise: a description of the general nature of trajectories of critical points in scale-space. an estimation of the drift velocity of critical points and edges. an analysis of the qualitative behaviour of critical points in bifurcation situations. a classification of what types of blob bifurcations are possible.
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