In mobile cloud computing (MCC) paradigm, cloud service providers not only offer powerful cloud data centers but also provide small-scale cloudlets in some strategic locations for mobile users to access their rich res...
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ISBN:
(纸本)9781479905379
In mobile cloud computing (MCC) paradigm, cloud service providers not only offer powerful cloud data centers but also provide small-scale cloudlets in some strategic locations for mobile users to access their rich resources. Due to the flexibility and locality of cloudlets, most requests of mobile users can be processed locally. However, the cloudlets usually have limited resources and processing abilities, which implies that they may not be capable to process every incoming request. Instead, some resource-intensive requests need to be sent to remote data centers for processing and such a processing is transparent to users. In this paper, we address the online request admission issue in a cloudlet with an objective to maximize the system throughput, for which we first propose a novel admission cost model to model critical resource consumptions. We then devise efficient control algorithms for online request admissions. We finally conduct experiments by simulations to evaluate the performance of the proposed algorithms. Experimental results indicate that the proposed algorithms are promising and outperform other heuristics.
In this paper, we present the design of an autopilot embedded system applied to control a four rotor mini helicopter, called X4-flyer. The main goal is to achieve a stable flight, controlling the vehicle attitude;this...
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ISBN:
(纸本)9781479923779
In this paper, we present the design of an autopilot embedded system applied to control a four rotor mini helicopter, called X4-flyer. The main goal is to achieve a stable flight, controlling the vehicle attitude;this is done using two control strategies: a linear PD control and nonlinear nested saturations control. The onboard system uses a simplified architecture and the main processor has a structured program to handle the data acquisition, and calculates the control to send actuators correction to get a desired set point. Real time experiments, in a pivoted platform, show that the autopilot is a reliable low cost platform.
In this paper, we experimentally investigated a new reinforcement learning based robot shared control algorithm for walking-aid robot. To autonomously adapt to different user operation habits and motor ability, robot ...
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ISBN:
(纸本)9781479926268
In this paper, we experimentally investigated a new reinforcement learning based robot shared control algorithm for walking-aid robot. To autonomously adapt to different user operation habits and motor ability, robot dynamically adjusted user control weight by proposed algorithm. The weight adjustment is performed online based on user control efficiency, current robot walking state and environment information by re-inforcement learning algorithm. The shared control synthetizes the final robot velocity according to the control weight. The effectiveness of proposed reinforcement learning based shared control algorithm is verified by experiments in a specified environment.
In conventional power system operation, droop control methods are used to facilitate load sharing among different generation sources. This method compensates for both active and reactive power imbalances by adjusting ...
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ISBN:
(纸本)9781479923250
In conventional power system operation, droop control methods are used to facilitate load sharing among different generation sources. This method compensates for both active and reactive power imbalances by adjusting the output voltage magnitude and frequency of the generating unit. Both P-ω and Q-V droops have been used in synchronous machines for decades. Similar droop controllers were used in this study to develop a control algorithm for a three-phase isolated (islanded) inverter. Controllers modeled in a synchronous dq reference frame were simulated in PLECS and validated with the hardware setup. A small-signal model based on an averaged model of the inverter was developed to study the system's dynamics. The accuracy of this mathematical model was then verified using the data obtained from the experimental and simulation results. This validated model is a useful tool for the further dynamic analysis of a microgrid.
It is widely known that Ethernet networks are susceptible to high-power electromagnetics (HPEM). Even with electromagnetic disturbance levels below the threshold, at which a hardware failure of components can be obser...
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ISBN:
(纸本)9781479955466
It is widely known that Ethernet networks are susceptible to high-power electromagnetics (HPEM). Even with electromagnetic disturbance levels below the threshold, at which a hardware failure of components can be observed, there are impacts on the data transmission between two computers. A typical effect on the application level is a decrease of the maximum data rate between two endpoints with a higher field strength until the transmission completely breaks down. To quantify the effect of electromagnetic disturbances it is necessary to distinguish between effects which are software-related due to control algorithms and applications behaviour on higher protocol layers, and hardware-related effects caused by physical interaction between the network components and the disturbance. This paper shows the results of a new measurement method compared to classical tests using a FTP data transmission.
In this paper, using a hybrid control technique for robotic rehabilitation, a singularity-free control algorithm for the safe robot-human interaction is proposed. With the use of max-plus algebra, a hybrid controller ...
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ISBN:
(纸本)9781479931170
In this paper, using a hybrid control technique for robotic rehabilitation, a singularity-free control algorithm for the safe robot-human interaction is proposed. With the use of max-plus algebra, a hybrid controller is designed to guarantee feasible robot motion in the vicinity of the kinematic singularities or going through and staying at the singular configuration. The approach taken in this paper uses a model free impedance control and hence it does not require any information about the model except the upper bounds on the system matrix. The stability of the approach is investigated using multiple Lyapunov function theory. The proposed control algorithm is applied to a six-axis industrial robot arm, namely PUMA 560 and the results demonstrate the validity of the proposed control scheme.
Implementations of the Advanced Encryption Standard (AES) have rapidly grown in various applications including telecommunications, finance and networks that require a low power consumption and low cost design. Present...
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Implementations of the Advanced Encryption Standard (AES) have rapidly grown in various applications including telecommunications, finance and networks that require a low power consumption and low cost design. Presented in this thesis is a new 8-bit stream cipher architecture core for an application specific integrated circuit AES crypto-processor. The chip area and power are optimised along with high throughput by employing circuit-level techniques, resource sharing and low supply voltage. The proposed design includes a novel S-box/ InvS-box, MixColumn/ InvMixColumn and ShiftRow/ InvShiftRow with a novel low power Exclusive OR (XOR) gate applied to all sub systems to minimise the power consumption. It is implemented in a 130nm CMOS process and supports both encryption and decryption in Electronic Codebook Mode (EBC) using 128-bit keys with a throughput of 0.05Gbit/s (at 100MHz clock). This design utilises 3152 gate equivalents, including an on-the-fly key scheduling unit along with 4.23μW/MHz power consumption. The area of the chip is 640μm×325μm (0.208 square mm), excluding the bonding pads. Compared to other 8-bit implementations, the proposed design achieves a smaller chip size along with higher throughput and lower power dissipation. This thesis also describes a new fault detection scheme for S-box/ InvS-box that is parity prediction based to protect the key from fault attacks.%%%%The following articles were removed due to copyright restrictions:Ahmad, N., Hasan, R. (2013) "A 0.8 V 0.23 nW 1.5 ns full-swing pass-transistor XOR gate in 130 nm CMOS", Active and passive electronic components, 1-6; Ahmad, N., Rezaul Hasan, S.M., (2012) "Efficient integrated AES crypto-processor architecture for 8-bit stream cipher", Electronic Letters, IET, 48:23, 1456-1457; Ahmad, N., Rezaul Hasan, S.M. (2013) "Low-power compact composite field AES S-Box/Inv S-Box design in 65nm CMOS using Novel XOR Gate", Integration, the VLSI Journal, 46:4, 333-345;Ahmad, N., Hasan, R. (2012) "T
We present a multihistogram reweighting technique for nonequilibrium Markov chains with discrete energies. The method generalizes the single-histogram method of Yin et al. [Phys. Rev. E 72, 036122 (2005)], making it p...
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We present a multihistogram reweighting technique for nonequilibrium Markov chains with discrete energies. The method generalizes the single-histogram method of Yin et al. [Phys. Rev. E 72, 036122 (2005)], making it possible to calculate the time evolution of observables at a posteriori chosen couplings based on a set of simulations performed at other couplings. In the same way as multihistogram reweighting in an equilibrium setting improves the practical reweighting range as well as use of available data compared to single-histogram reweighting, the method generalizes the multihistogram advantages to nonequilibrium simulations. We demonstrate the procedure for the Ising model with Metropolis dynamics, but stress that the method is generally applicable to a range of models and Monte Carlo update schemes.
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