50 resultados para flexible motion control


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In the past few years, cloud computing has emerged as one of the most influential paradigms in the IT industry. As promising as it is, this paradigm brings forth many new challenges for data security because users have to outsource sensitive data on untrusted cloud servers for sharing. In this paper, to guarantee the confidentiality and security of data sharing in cloud environment, we propose a Flexible and Efficient Access Control Scheme (FEACS) based on Attribute-Based Encryption, which is suitable for fine-grained access control. Compared with existing state-of-the-art schemes, FEACS is more practical by following functions. First of all, considering the factor that the user membership may change frequently in cloud environment, FEACS has the capability of coping with dynamic membership efficiently. Secondly, full logic expression is supported to make the access policy described accurately and efficiently. Besides, we prove in the standard model that FEACS is secure based on the Decisional Bilinear Diffie-Hellman assumption. To evaluate the practicality of FEACS, we provide a detailed theoretical performance analysis and a simulation comparison with existing schemes. Both the theoretical analysis and the experimental results prove that our scheme is efficient and effective for cloud environment.

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Abstract—Nowadays, classical washout filters are extensively used in commercial motion simulators. Even though there are several advantages for classical washout filters, such as short processing time, simplicity and ease of adjustment, they have several shortcomings. The main disadvantage is the fixed scheme and parameters of the classical washout filter cause inflexibility of the structure and thus the resulting simulator fails to suit all circumstances. Moreover, it is a conservative approach and the platform cannot be fully exploited. The aim of this research is to present a fuzzy logic approach and take the human perception error into account in the classical motion cueing algorithm, in order to improve both the physical limits of restitution and realistic human sensations. The fuzzy compensator signal is applied to adjust the filtered signals on the longitudinal and rotational channels online, as well as the tilt coordination to minimize the vestibular sensation error below the human perception threshold. The results indicate that the proposed fuzzy logic controllers significantly minimize the drawbacks of having fixed parameters and conservativeness in the classical washout filter. In addition, the performance of motion cueing algorithm and human perception for most occasions is improved.

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The implementation of Kanban-based production control systems may be difficult in make-to-order environments such as job shops. The flexible manufacturing approach constitutes a promising solution to adapt the Kanban method to such environments. This paper presents an information flow modelling approach for specifying the operational planning and control functions of the Kanban-controlled shopfloor control system (KSCS) in a flexible manufacturing environment. By decomposing the KSCS control functionalities, we have created the system information flow model through the data flow diagrams of Structured Systems Analysis Methodology. The data flow diagrams serve effective system specifications for communicating the system operations to participants of different disciplines as well as the system model for the design and development of KSCS.

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Micro-electro-mechanical system (MEMS) technology offers sensors with lower cost, smaller size, lower power consumption. In this paper, a kind of low cost motion-sensing system based MEMS sensors is developed. The objective of the design is low cost, small volume and light weight in order to be used in many fields. The constituting principle of the system is described. Algorithms and hardware of the system are researched. And the definition of coordinate, calculation of pose angle, transform of acceleration and calculation of the velocities and displacement of the moving object are presented with corresponding mathematics model and algorithms. The experiments are carried out in principle and results are given. It is proved that the low cost motion-sensing system is effective and correct.

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Low cost robotic detectors are a promising new approach to combat the disturbing landmine crisis. In this paper a low-cost robotic solution is proposed, we present several control techniques used to improve the precision of the robotic motion. A P and PD controller is applied, and it is concluded that a cascaded control system provides a more stable and accurate response. Two search patterns for landmine detection are considered, rectangular and spiral, these are used to analyse the effectiveness of the control system.

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In recent years many changes to the funding and management of universities have taken place. In the current climate of academia in Australia professional academics find themselves immersed in the culture of the managed university that uses the rhetoric of commitment to flexible delivery to put in place systems designed to increase accountability, surveillance and control. At the same time some argue that the focus on research, quality teaching and effective pedagogy has lessened. The empirical research base for this paper has enabled me to better understand some of the emerging trends my university. It looks at how changes to the experience of being academic impact on the work of academics as the power relations of the university continuously reposition them, and how academics in turn display resistance technologies. Changes to the technologies of management/administration of the university have resulted in what some academics have described as a loss of valuing of their knowledge and expertise and which may be seen by some as a threat to their opportunities to conduct productive educational inquiry.

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Background : Chronic plantar heel pain (CPHP) is one of the most common musculoskeletal disorders of the foot, yet its aetiology is poorly understood. The purpose of this study was to examine the association between CPHP and a number of commonly hypothesised causative factors.

Methods :
Eighty participants with CPHP (33 males, 47 females, mean age 52.3 years, S.D. 11.7) were matched by age (± 2 years) and sex to 80 control participants (33 males, 47 females, mean age 51.9 years, S.D. 11.8). The two groups were then compared on body mass index (BMI), foot posture as measured by the Foot Posture Index (FPI), ankle dorsiflexion range of motion (ROM) as measured by the Dorsiflexion Lunge Test, occupational lower limb stress using the Occupational Rating Scale and calf endurance using the Standing Heel Rise Test.

Results : Univariate analysis demonstrated that the CPHP group had significantly greater BMI (29.8 ± 5.4 kg/m2 vs. 27.5 ± 4.9 kg/m2; P < 0.01), a more pronated foot posture (FPI score 2.4 ± 3.3 vs. 1.1 ± 2.3; P < 0.01) and greater ankle dorsiflexion ROM (45.1 ± 7.1° vs. 40.5 ± 6.6°; P < 0.01) than the control group. No difference was identified between the groups for calf endurance or time spent sitting, standing, walking on uneven ground, squatting, climbing or lifting. Multivariate logistic regression revealed that those with CPHP were more likely to be obese (BMI ≥ 30 kg/m2) (OR 2.9, 95% CI 1.4 – 6.1, P < 0.01) and to have a pronated foot posture (FPI ≥ 4) (OR 3.7, 95% CI 1.6 – 8.7, P < 0.01).

Conclusion : Obesity and pronated foot posture are associated with CPHP and may be risk factors for the development of the condition. Decreased ankle dorsiflexion, calf endurance and occupational lower limb stress may not play a role in CPHP.

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Internet Protocol (IP) traceback is the enabling technology to control Internet crime. In this paper, we present a novel and practical IP traceback system called Flexible Deterministic Packet Marking (FDPM) which provides a defense system with the ability to find out the real sources of attacking packets that traverse through the network. While a number of other traceback schemes exist, FDPM provides innovative features to trace the source of IP packets and can obtain better tracing capability than others. In particular, FDPM adopts a flexible mark length strategy to make it compatible to different network environments; it also adaptively changes its marking rate according to the load of the participating router by a flexible flow-based marking scheme. Evaluations on both simulation and real system implementation demonstrate that FDPM requires a moderately small number of packets to complete the traceback process; add little additional load to routers and can trace a large number of sources in one traceback process with low false positive rates. The built-in overload prevention mechanism makes this system capable of achieving a satisfactory traceback result even when the router is heavily loaded. The motivation of this traceback system is from DDoS defense. It has been used to not only trace DDoS attacking packets but also enhance filtering attacking traffic. It has a wide array of applications for other security systems.

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The present invention provides remote interfacing utilising haptic technology. In a first aspect there is provided a haptic grasping interface comprising a plurality of finger interaction points, with actuators connected at one end to an actuator control mechanism. The mechanism is mounted remotely from the grasping interface, inverse to the finger interaction points, for manipulation of these points. The grasping points comprise pulleys which route the actuators through a cable tension and transmission system. A second aspect provides haptic augmentation to an operator, which indicates to the operator the state of a control input to a controlled device. A third aspect provides a means of simulating motion where haptic feedback is provided to a user in correspondence with the movement of the user within a pod environment.

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The present invention provides remote interfacing utilising haptic technology. In a first aspect there is provided a haptic grasping interface comprising a plurality of finger interaction points, with actuators connected at one end to an actuator control mechanism. The mechanism is mounted remotely from the grasping interface, inverse to the finger interaction points, for manipulation of these points. The grasping points comprise pulleys which route the actuators through a cable tension and transmission system. A second aspect provides haptic augmentation to an operator, which indicates to the operator the state of a control input to a controlled device. A third aspect provides a means of simulating motion where haptic feedback is provided to a user in correspondence with the movement of the user within a pod environment.

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The present invention provides remote interfacing utilising haptic technology. In a first aspect there is provided a haptic grasping interface comprising a plurality of finger interaction points, with actuators connected at one end to an actuator control mechanism. The mechanism is mounted remotely from the grasping interface, inverse to the finger interaction points, for manipulation of these points. The grasping points comprise pulleys which route the actuators through a cable tension and transmission system. A second aspect provides haptic augmentation to an operator, which indicates to the operator the state of a control input to a controlled device. A third aspect provides a means of simulating motion where haptic feedback is provided to a user in correspondence with the movement of the user within a pod environment.

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The present invention provides remote interfacing utilising haptic technology. In a first aspect there is provided a haptic grasping interface comprising a plurality of finger interaction points, with actuators connected at one end to an actuator control mechanism. The mechanism is mounted remotely from the grasping interface, inverse to the finger interaction points, for manipulation of these points. The grasping points comprise pulleys which route the actuators through a cable tension and transmission system. A second aspect provides haptic augmentation to an operator, which indicates to the operator the state of a control input to a controlled device. A third aspect provides a means of simulating motion where haptic feedback is provided to a user in correspondence with the movement of the user within a pod environment.

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The present invention provides remote interfacing utilising haptic technology. In a first aspect there is provided a haptic grasping interface comprising a plurality of finger interaction points, with actuators connected at one end to an actuator control mechanism. The mechanism is mounted remotely from the grasping interface, inverse to the finger interaction points, for manipulation of these points. The grasping points comprise pulleys which route the actuators through a cable tension and transmission system. A second aspect provides haptic augmentation to an operator, which indicates to the operator the state of a control input to a controlled device. A third aspect provides a means of simulating motion where haptic feedback is provided to a user in correspondence with the movement of the user within a pod environment.

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Load-induced strains applied to bone can stimulate its development and adaptation. In order to quantify the incident strains within the skeleton, in vivo implementation of strain gauges on the surfaces of bone is typically used. However, in vivo strain measurements require invasive methodology that is challenging and limited to certain regions of superficial bones only such as the anterior surface of the tibia. Based on our previous study [Al Nazer et al. (2008) J Biomech. 41:1036–1043], an alternative numerical approach to analyse in vivo strains based on the flexible multibody simulation approach was proposed. The purpose of this study was to extend the idea of using the flexible multibody approach in the analysis of bone strains during physical activity through integrating the magnetic resonance imaging (MRI) technique within the framework. In order to investigate the reliability and validity of the proposed approach, a three-dimensional full body musculoskeletal model with a flexible tibia was used as a demonstration example. The model was used in a forward dynamics simulation in order to predict the tibial strains during walking on a level exercise. The flexible tibial model was developed using the actual geometry of human tibia, which was obtained from three-dimensional reconstruction of MRI. Motion capture data obtained from walking at constant velocity were used to drive the model during the inverse dynamics simulation in order to teach the muscles to reproduce the motion in the forward dynamics simulation. Based on the agreement between the literature-based in vivo strain measurements and the simulated strain results, it can be concluded that the flexible multibody approach enables reasonable predictions of bone strain in response to dynamic loading. The information obtained from the present approach can be useful in clinical applications including devising exercises to prevent bone fragility or to accelerate fracture healing.