| 51. |
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| 52. |
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| 53. |
- Ylinenpää, Håkan, et al.
(författare)
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Northern light or out in the cold : comparison of two Nordic regions
- 1998
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The development of regions has attracted substantial interest during the recent decades, involving several studies of ‘industrial districts', ‘developing regions', ‘hi-tech regions' and ‘entrepreneurial districts'. Different propositions regarding how the development of dynamic regions can be understood has thus, with different theoretical approaches, been put forward. This article aims to increase our knowledge about how the factors behind the development of regions can be understood. The point of departure is Porter's ‘Diamond Model', which is applied as a theoretical framework for an analysis of two Nordic regions: The Oulu region (the city Oulu and the county of Pohjois Pohjanmaa) in northern Finland and the Luleå region (the city of Luleå and the county of Norrbotten) in northern Sweden. By utilising different data sources, interviews with key actors in the two regions as well as statistical data and previous studies, the study identifies four main factors behind the notably more favourable development of the Oulu region. These factors relate to the two cities' different positions in their national hierarchy of cities, different modes of co-operation between local and regional key actors, different roles as demanding customers played by the dominant companies in the regions, and structural differences regarding the role of emerging versus mature industries. Also factors with minor and often indirect importance for explaining occurring differences are identified in the article.
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| 54. |
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| 55. |
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| 56. |
- Berbyuk, Viktor, 1953
(författare)
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Dynamics and optimal control of biotechnical systems "Man-Prosthesis"
- 1997
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Ingår i: IUTAM Symposium on Interaction Between Dynamics and Control in Advanced Mechanical Systems, Ed. D. van Campen, Kluwer Academic Publishers, 1997. - Dordrecht : Springer Netherlands. ; , s. 35-42
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Konferensbidrag (refereegranskat)abstract
- In the paper, a mathematical model is proposed for investigating the controlled motion of human locomotion system (HLS) with an above-knee prosthesis. To provide insight into the interaction between dynamics and control in biotechnical system Man-Prosthesis the energy optimal control problem of the HLS wearing a lower limb prosthesis has been considered. The algorithm is based on special conversion of the optimal control problem for a nonlinear dynamical system which models HLS into a standard nonlinear programming problem. A number of energy-optimal control problems of human locomotion with an artificial leg, and optimization problems for the constructive parameters of the prostheses under different boundary conditions and constraints have been solved. The numerical results obtained were compared with experimental data for normal human locomotion. The energy-optimal elastic and viscoelastic characteristics of the ankle and knee joints of the prostheses have been determined.
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| 57. |
- Berbyuk, Viktor, 1953
(författare)
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Multibody systems modeling and optimization problems of lower limb prostheses
- 1996
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Ingår i: 1996 IUTAM Symposium on Optimization of Mechanical Systems. - Dordrecht : Springer Netherlands. ; , s. 25-32
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Konferensbidrag (refereegranskat)abstract
- To study the effect of prosthesis design on the kinematic, dynamic, energetic and other characteristics of an amputee's locomotion and to improve and create new efficient lower limb prostheses it is expendient to use mathematical modeling of a human walk process and dynamic optimization techniques. In this paper a mathematical model is proposed for investigating the dynamics of a man's skeletal system (MSS) with a below-knee prosthesis. A MSS is simulated by a plane controlled dynamic system of rigid masses. The controlled motions of the system are described by Lagrange's equations of the second kind, and for the expressions for kineto-static balance of the prosthesis under the action of ankle and metatarsal moments and the forces of reactions are derived. An algorithm is construced for solving the problem of human gait dynamics with a below-knee prosthesis. The series of dynamics problems for multibody biothechnical system "Man-Prosthesis" and optimization of structural parameters of the artificial lower extremity of a man has been solved.
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| 58. |
- Brunnström, Kjell, et al.
(författare)
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Scale and Resolution in Active Analysis of Local Image Structure
- 1990
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Ingår i: Image and Vision Computing. - : Elsevier. ; 8:4, s. 289-296
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Tidskriftsartikel (refereegranskat)abstract
- Focus-of-attention is extremely important in human visual perception. If computer vision systems are to perform tasks in a complex, dynamic world they will have to be able to control processing in a way that is analogous to visual attention in humans. Problems connected to foveation (examination of selected regions of the world at high resolution) are examined. In particular, the problem of finding and classifying junctions from this aspect is considered. It is shown that foveation as simulated by controlled, active zooming in conjunction with scale-space techniques allows for robust detection and classification of junctions.
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| 59. |
- Elgered, Gunnar, 1955, et al.
(författare)
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Ground-based microwave radiometry and long-term observations of atmospheric water vapor
- 1998
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Ingår i: Radio Science. - 0048-6604 .- 1944-799X. ; 33:3, s. 707-717
-
Tidskriftsartikel (refereegranskat)abstract
- Microwave radiometer data and radiosonde data from the time period 1981-1995 have been used to study long-term trends in the integrated precipitable water vapor (IPWV). The two instruments have operated 37 km apart on the Swedish west coast. Model parameters are estimated for the entire data sets as well as for subsets of the data. The IPWV model parameters are a mean value, a linear drift with time, and the amplitude and phase of an annual component. The radiosonde data, which are uniformly sampled in time, show an increase in the IPWV of 0.03 mm/yr with a statistical standard deviation of 0.01 mm. The microwave radiometer data, which are not at all uniformly sampled in time, show -0.02+/-0.01 mm/yr. We show that the disagreement is caused by the different sampling of the data for the two instruments. When the two data sets are reduced to include only data that are sampled simultaneously, we find an agreement between all estimated model parameters, given their statistical uncertainties. This suggests that if the microwave radiometer had also been operating continuously over the 15-year period, its data would have implied a linear trend similar to the result obtained from the radiosonde data. The general quality of the data, in terms of the short time scatter, has been improved over the time period. The root mean square (RMS) difference between the IPWV measured by the radiometer and by the radiosondes was 2.1 mm during the first 5 years and was reduced to 1.6 mm during the last 4 years. These values include the real difference in the IPWV between the two sites. The bias, radiometer-radiosonde, was 0.1 mm for the whole data set and varied between -0.2 and 0.9 mm for smaller data sets of a few years.
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| 60. |
- Lindeberg, Tony, 1964-, et al.
(författare)
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Scale-space with causal time direction
- 1996
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Konferensbidrag (refereegranskat)abstract
- This article presents a theory for multi-scale representation of temporal data. Assuming that a real-time vision system should represent the incoming data at different time scales, an additional causality constraint arises compared to traditional scale-space theory—we can only use what has occurred in the past for computing representations at coarser time scales. Based on a previously developed scale-space theory in terms of noncreation of local maxima with increasing scale, a complete classification is given of the scale-space kernels that satisfy this property of non-creation of structure and respect the time direction as causal. It is shown that the cases of continuous and discrete time are inherently different.
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