| 1. |
- Törnhage, Carl-Johan, et al.
(author)
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Short- and long-term effects of tactile massage on salivary cortisol concentrations in Parkinsons disease : a randomised controlled pilot study
- 2013
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In: BMC Complementary and Alternative Medicine. - : BioMed Central (BMC). - 1472-6882. ; 13:357
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Journal article (peer-reviewed)abstract
- BACKGROUND:Parkinson's disease (PD) is a chronic neurodegenerative disorder with limited knowledge about the normal function and effects of non-pharmacological therapies on the hypothalamic-pituitary-adrenal (HPA) axis. The aim of the study was to analyse the basal diurnal and total secretion of salivary cortisol in short- and long-term aspects of tactile massage (TM).METHODS:Design: Prospective, Controlled and Randomised Multicentre Trial.Setting and interventions: Forty-five women and men, aged 50-79 years, were recruited. Twenty-nine of them were blindly randomised to tactile massage (TM) and 16 of them to the control group, rest to music (RTM). Ten interventions were given during 8 weeks followed by a 26 weeks of follow up. Salivary cortisol was collected at 8 am, 1 pm, 8 pm, and 8 am the next day, on five occasions. With the first and eighth interventions, it was collected immediately before and after intervention.Main outcome measures: The primary aim was to assess and compare cortisol concentrations before and immediately after intervention and also during the follow-up period. The secondary aim was to assess the impact of age, gender, body mass index (BMI), duration and severity of PD, effects of interventional time-point of the day, and levodopa doses on cortisol concentration.RESULTS:The median cortisol concentrations for all participants were 16.0, 5.8, 2.8, and 14.0 nmol/L at baseline, later reproduced four times without significant differences. Cortisol concentrations decreased significantly after TM intervention but no change in diurnal salivary cortisol pattern was found. The findings of reduced salivary cortisol concentrations immediately after the interventions are in agreement with previous studies. However, there was no significant difference between the TM and control groups. There were no significant correlations between cortisol concentrations and age, gender, BMI, time-point for intervention, time interval between anti-parkinson pharmacy intake and sampling, levodopa doses, duration, or severity of PD.CONCLUSIONS:Diurnal salivary cortisol rhythm was normal. Salivary cortisol concentrations were significantly reduced after the TM intervention and after RTM, but there were no significant differences between the groups and no sustained long-term effect. No associations were seen between salivary cortisol concentration and clinical and/or pharmacological characteristics.
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| 2. |
- Amani, Payam, et al.
(author)
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Application of Control Theory to a Commercial Mobile Service Support System
- 2012
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In: International Journal on Advances in Telecommunications. - 1942-2601. ; 5:3&4
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Journal article (peer-reviewed)abstract
- The Mobile Service Support system (MSS), which Ericsson AB develops, handles the setup of new subscribers and services into a mobile network. Experience from deployed systems show that traffic monitoring and control of the system will be crucial for handling overload situations that may occur at sudden traffic surges. In this paper we identify and explore some important control challenges for this type of systems. Further, we present analysis and experiments showing some advantages of proposed solutions. First, we develop a load-dependent server model for the system, which is validated in testbed experiments. Further, we propose a control design based on the model, and a method for estimation of response times and arrival rates. The main contribution of this paper is that we show how control theory methods and analysis can be used for commercial telecom systems. Parts of our results have been implemented in commercial products, validating the strength of our work.
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| 3. |
- Cho, Jang Ho, et al.
(author)
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Design of an Intermediate Layer to Enhance Operator Awareness and Safety in Telesurgical Systems
- 2012
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In: Proc. 2012 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS2012), October 7-12, 2012. Vilamoura, Algarve, Portugal. - 2153-0858 .- 2153-0866. ; , s. 1292-1297
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Conference paper (peer-reviewed)abstract
- This paper presents a novel control architecture for enhanced operator awareness and improved safety in telesurgical systems. We introduce an intermediate layer between the master and slave sides which allows us to modify the slave motion for safety and the force feedback for operator awareness. The intermediate layer is then designed with a performance objective for the specific task at hand. The control scheme is validated via experiments using a suture and an industrial manipulator. More specifically we show that operator awareness should be implemented as an integrated part of the safety level to maintain safety during surgery.
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| 4. |
- Dellkrantz, Manfred, et al.
(author)
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Event-Based Response Time Estimation
- 2012
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In: [Host publication title missing].
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Conference paper (peer-reviewed)abstract
- Response time is a measure of quality of service in com- puter systems. Estimation techniques, suitable for support systems for mobile phone systems, are explored. These sys- tems are complex queueing systems with large databases. The trac generated by users and system adminstrators changes rapidly, some loads can be measured other cannot. Attempts to capture all details give models that are not suit- able for on-line control. Estimators based on continuous flow models with event based measurements are designed using extended Kalman ltering. The estimators are compared with simple-data based estimators.
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| 5. |
- From, Pål Johan, et al.
(author)
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Hybrid Stiff/Compliant Workspace Control for Robotized Minimally Invasive Surgery
- 2014
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In: Proc. 2014 5th IEEE RAS & EMBS International Conference on Biomedical Robotics and Biomechatronics (BioRob 2014), August 12-15, 2014. São Paulo, Brazil. - 2155-1774. - 9781479931262 ; , s. 345-351
-
Conference paper (peer-reviewed)abstract
- This paper presents a novel control architecture for hybrid stiff and compliant control for minimally invasive surgery which satisfies the constraints of zero lateral velocity at the entry point for serial manipulators. For minimally invasive surgery it is required that there is no sideways motion at the point where the robots enter the abdomen. This is necessary to avoid any damage to the patient's body when the robot moves. We solve this at a kinematic level, i.e., we find a Jacobian matrix that maps the velocities in joint space to the end-effector velocities and at the same time guarantees that certain velocities at the entry point are zero. Because the new velocity variables are defined in the end-effector workspace we can use these for hybrid motion/force control. The approach is verified experimentally by implementing hybrid stiff and compliant control of the end effector and we show that the insertion point constraints are always satisfied.
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| 6. |
- Kihl, Maria, et al.
(author)
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The Challenge of Cloud Control
- 2013
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In: The 8th International Workshop on Feedback Computing (Feedback Computing '13).
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Conference paper (peer-reviewed)abstract
- Today’s cloud data center infrastructures are not even near being able to cope with the enormous and rapidly vary-ing capacity demands that will be reality in a near future. So far, very little is understood about how to transform today’s data centers (being large, power-hungry facilities, and operated through heroic efforts by numerous adminis-trators) into a self-managed, dynamic, and dependable infrastructure, constantly delivering expected QoS with rea-sonable operation costs and acceptable carbon footprint for large-scale services with sometimes dramatic variations in capacity demands. In this paper, we discuss some of the major challenges for resource-optimized cloud data cen-ter. We propose a new research area called Cloud Control, which is a control theoretic approach to a range of cloud management problems, aiming to transform today´s static and energy consuming cloud data centers into self-managed, dynamic, and dependable infrastructures, constantly delivering expected quality of service with acceptable operation costs and carbon footprint for large-scale services with varying capacity demands.
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| 7. |
- Olofsson, Björn, et al.
(author)
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Optimal Tracking and Identification of Paths for Industrial Robots
- 2011
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In: Proceedings of the 18th IFAC World Congress, 2011. ; , s. 1126-1132
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Conference paper (peer-reviewed)abstract
- This paper presents results from time-optimal path tracking for industrial robots. More specifically, three subproblems are studied and experimentally evaluated. The first is a contact-force control approach for determining the geometric robot motion, such that the tool centre point of the robot is moved according to the specification. The second problem is off-line solution of the optimisation problem describing the time-optimal path tracking problem, by using software which allows highlevel implementation and solution of optimisation problems. The third problem is robust control of the robot during real-time path tracking based on the optimisation results determined off-line. An earlier developed control structure for robust control is implemented and tested in a robot system. This paper discusses the theory behind time-optimal path tracking and presents experimental results. Both contact-force controlled path identification and real-time path tracking of the identified path are evaluated on a 6-DOF industrial robot of type IRB140 from ABB.
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| 8. |
- Pettersson, Anders, et al.
(author)
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Analysis of Linear L1 Adaptive Control Architectures for Aerospace Applications
- 2012
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In: IEEE 51st Annual Conference on Decision and Control (CDC), 2012. - 0743-1546. - 9781467320658 ; , s. 1136-1141
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Conference paper (peer-reviewed)abstract
- In some situations the closed-loop system obtained by L1 adaptive control is equivalent to linear systems. The architectures of these systems are investigated and compared with internal model control and the input observer architecture. The analysis is focused on aerospace application. An effort has been made to understand and describe what fundamental control characteristic of flying applications that make L1 adaptive controllers suitable for the task.
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| 9. |
- Pettersson, Anders, et al.
(author)
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Augmenting L1 Adaptive Control of Piecewise Constant Type to a Fighter Aircraft. Performance and Robustness Evaluation for Rapid Maneuvering
- 2012
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In: AIAA Guidance, Navigation, and Control Conference, 13 - 16 August 2012.
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Conference paper (peer-reviewed)abstract
- An L1 adaptive controller of piecewise constant type has been applied to a fighter aircraft by augmenting it to a linear state-feedback controller. Angle of attack and sideslip as well as velocity vector roll rate is demanded and controlled. It is relatively easy to design a controller augmentation this way; few parameters need to be tuned. To design an L1-controller for roll/pitch/yaw-motion of an aircraft, a five-state reference system with desired dynamics is created and three bandwidths of low-pass filters are chosen. The L1-controller activates when the aircraft aided by the feedback controller deviates from the reference dynamics. Load disturbance rejection is improved when the L1-controller is active. Results from simulations with different kinds of deviations from the nominal aircraft are presented. Special non-linear design elements need to be introduced if actuator dynamics, including rate limits, interfere with reference system dynamics. Since an L1 adaptive controller of piecewise constant type in its original form is linear time invariant, frequency domain analysis is presented, including comparisons to a typical linear state-feedback controller.
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| 10. |
- Pettersson, Anders, et al.
(author)
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Nonlinear Feedforward and Reference Systems for Adaptive Flight Control
- 2013
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In: 2013 AIAA Guidance, Navigation, and Control Conference. - Reston, Virginia : American Institute of Aeronautics and Astronautics.
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Conference paper (peer-reviewed)abstract
- Use of feedforward can alleviate feedback and adaptive actions. Feedforward signals can be generated from reference models and the same models can also be used as reference models in adaptive control. A method for designing the reference models is presented in the paper. By exploiting the structure of the equations describing air vehicles it is possible to find reference models that scale to the present flight condition and vehicle configuration. Such reference systems are derived for flying vehicles in a generic manner, suitable for both winged aircraft and missiles. The same type of reference systems are also used to create trajectories for feedforward signals that compensate known plant non-linearities.
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