| 1. |
- Thunberg, Hans, 1956-
(författare)
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A recycled characterization of kneading sequences
- 1999
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Ingår i: International Journal of Bifurcation and Chaos in Applied Sciences and Engineering. - : World Scientific. - 0218-1274. ; 9:9, s. 1883-1887
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Tidskriftsartikel (refereegranskat)abstract
- For any infinite sequence E on two symbols one can define two sequences of positive integers S(E) (the splitting times) and T(E) (the cosplitting times), which each describe the self-replicative structure of E. If E is the kneading sequence of a unimodal map, it is known that S(E) and T(E) carry a lot of information on the dynamics, and that they are disjoint. We show the reverse implication: A nonperiodic sequence E is the kneading sequence of some unimodal map if the sequences S(E) and T(E) are disjoint.
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| 2. |
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| 3. |
- 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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| 4. |
- Axelsson, B.O.M., et al.
(författare)
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Studies of the main cutting force at and near a cutting edge
- 1993
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Ingår i: European Journal of Wood and Wood Products. - 0018-3768 .- 1436-736X. ; 51:1, s. 43-48
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Tidskriftsartikel (refereegranskat)abstract
- The present work is a study of how various parameters affect the cutting forces at, and near a cutting edge when cutting wood at full speed and with all cutting edges of the tool. Statistical methods from experimental results are used to develop a model
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| 5. |
- Lundberg, Staffan, et al.
(författare)
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Cutting forces at and near a cutting edge
- 1992
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Ingår i: Better wood products through science : All-Division 5 conference "Forest Products". - Nancy : ENGREF. - 2907086030
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Konferensbidrag (refereegranskat)
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| 6. |
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| 7. |
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| 8. |
- Wik, Torsten, 1968, et al.
(författare)
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Transfer functions for series of continuously stirred biofilm reactors
- 1997
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- There is an increasing interest in modeling and applications of biofilm reactors. Commonly, biofilm reactors are modeled as a single continuously stirred biofilm reactor (CSBR), or as a series of such. The models can be used to extract information about the reactor, for design and to predict reactor effluent characteristics as a function of influent characteristics. A CSBR consists of a stirred tank, which the bulk water flows through, and from which substrates diffuse into a biofilm where they may be transformed into new substances by bacteria living in the biofilm. Here, standard assumptions are used to derive a general and flexible dynamic model of CSBR-systems, where the reaction kinetics are of zero or first order. An exact, and an approximate transfer function, which enables easy simulations, analysis, and implementation in real-time softwares, is derived. Particular focus is on pulse responses, which is an important experimental procedure in control and reactor design. Explicit equations for the pulse responses are presented, and parameter dependancy is discussed. Experimental data from a pilot plant nitrifying trickling filter are used to illustrate the use of transfer functions for identification of reactor and biofilm parameters.
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| 9. |
- Berbyuk, Viktor, 1953
(författare)
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On complete controllability of linear nonstationary systems
- 1993
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Ingår i: Journal of Soviet Mathematics. - 0090-4104. ; 67:2, s. 2973-2975
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Tidskriftsartikel (refereegranskat)abstract
- The concept of controllability is connected with the transfer of a dynamic system from one state to another by means of a control. An important problem in the theory of control systems is the search for necessary and sufficient conditions for complete controllability of dynamic systems. By using of the first integrals of the equations of unperturbed motion the necessary and sufficient conditions for complete controllability of linear nonstationary dynamic systems have been proposed.
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| 10. |
- Berbyuk, Viktor, 1953
(författare)
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The use of first integrals to synthesize the energetically optimal control of a nonlinear system
- 1997
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Ingår i: Journal of Mathematical Sciences. - 1573-8795 .- 1072-3374. ; 86:2, s. 2642-2645
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Tidskriftsartikel (refereegranskat)abstract
- In the paper a method of solving problems of optimal control of the motion of nonlinear dynamical systemswith respect to energy expenditure given a fixed time and fixed ends of the phase trajectory has been proposed. The method is based on the use of first integrals of the equations of free motion. The application of the method isillustrated by examples.
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