In this paper an analysis of productivity will be carried out from the resolution of the problem of trajectory planning of industrial robots. The analysis entails economic considerations, thus overcoming some limitati...
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In this paper an analysis of productivity will be carried out from the resolution of the problem of trajectory planning of industrial robots. The analysis entails economic considerations, thus overcoming some limitations of the existing literature. Two methodologies based on optimization-simulation procedures are compared to calculate the time needed to perform an industrial robot task. The simulation methodology relies on the use of robotics and automation software called GRASP. The optimization methodology developed in this work is based on the kinematics and the dynamics of industrial robots. It allows us to pose a multiobjective optimization problem to assess the trade-offs between the economic variables by means of the Pareto fronts. The comparison is carried out for different examples and from a multidisciplinary point of view, thus, to determine the impact of using each method. Results have shown the opportunity costs of non using the methodology with optimized time trajectories. Furthermore, it allows companies to stay competitive because of the quick adaptation to rapidly changing markets.
This study proposes a dual three-leg voltage source inverter (VSI)-based distribution static compensator to compensate unbalanced and non-linear loads in three-phase four-wire distribution systems. The proposed topolo...
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This study proposes a dual three-leg voltage source inverter (VSI)-based distribution static compensator to compensate unbalanced and non-linear loads in three-phase four-wire distribution systems. The proposed topology uses two three-leg inverters having common dc link with single dc capacitor and an additional small rating ac capacitor connected from the negative terminal of VSI to the system neutral. The proposed scheme with associated control algorithm has capability to compensate unbalanced non-linear load and hence makes source current as balanced sinusoidal and at desired power factor. The control algorithm also ensures the proper sharing of reactive, harmonics and unbalanced powers between two VSIs and controls the grid current total harmonic distortion level even in the presence of unbalanced and distorted voltages. The performance of the proposed scheme has been verified using simulation and experimental studies under different voltage conditions and detailed results are presented.
Three control algorithms are developed to stabilize an underactuated two-link robot at its unstable inverted position. The well-known linear quadratic regulator is described first. Next, a stabilization control law us...
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Three control algorithms are developed to stabilize an underactuated two-link robot at its unstable inverted position. The well-known linear quadratic regulator is described first. Next, a stabilization control law using partial feedback linearization is developed where the reference trajectories for the linearized degrees of freedom are designed by analyzing the zero dynamics. The linear quadratic regulator and partial feedback linearization control algorithms both assume an exact dynamic model. To deal with modeling inaccuracies, a robust controller using sliding mode concepts is supplied. Numerical simulations are presented. (C) 1998 John Wiley & Sons, Inc.
This research aims to propose a novel sub-optimal decentralised blanket coverage control algorithm, namely, 'one-Barrier-to-Blanket Coverage Algorithm' (BBCA) as well as a novel k-barrier coverage control algo...
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This research aims to propose a novel sub-optimal decentralised blanket coverage control algorithm, namely, 'one-Barrier-to-Blanket Coverage Algorithm' (BBCA) as well as a novel k-barrier coverage control algorithm, namely, 'one-to-k Barrier Coverage Algorithm' (1-kBCA) for self-deployed autonomous wireless sensor networks in the obstacle-free and convex deployment area. The motion coordination schemes developed in this research are based on the nearest neighbour techniques. Research indicates that simple motion coordination schemes have resulted in the powerful and intelligent control algorithms to achieve the desired coverage. Since the algorithms were developed based on simple local rules, they are indeed computationally efficient and ease the communication overheads. What is more, the superiorities of the proposed algorithms are nonetheless related to their uniformity, flexibility, simplicity, scalability as well as reliability. Instead of theoretical proofs as solid mathematical frameworks, computer simulations also have been presented to demonstrate the effectiveness of the proposed algorithms.
This paper considers some realization features of polynomial factoring algorithms for n-argument Boolean functions, as well as analyzes their computational complexity and necessary hardware resources.
This paper considers some realization features of polynomial factoring algorithms for n-argument Boolean functions, as well as analyzes their computational complexity and necessary hardware resources.
This paper presents a novel fuzzy inference model based on artificial hydrocarbon networks, a computational algorithm for modeling problems based on chemical hydrocarbon compounds. In particular, the proposed fuzzy-mo...
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This paper presents a novel fuzzy inference model based on artificial hydrocarbon networks, a computational algorithm for modeling problems based on chemical hydrocarbon compounds. In particular, the proposed fuzzy-molecular inference model (FIM-model) uses molecular units of information to partition the output space in the defuzzification step. Moreover, these molecules are linguistic units that can be partially understandable due to the organized structure of the topology and metadata parameters involved in artificial hydrocarbon networks. In addition, a position controller for a direct current (DC) motor was implemented using the proposed FIM-model in type-1 and type-2 fuzzy inference systems. Experimental results demonstrate that the fuzzy-molecular inference model can be applied as an alternative of type-2Mamdani's fuzzy control systems because the set of molecular units can deal with dynamic uncertainties mostly present in real-world control applications.
For the strapdown inertial navigation system (SINS), the procedure of initial alignment is a necessity before the navigation can commence. On the quasi-stationary base, the self-alignment can be fulfilled with the hig...
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For the strapdown inertial navigation system (SINS), the procedure of initial alignment is a necessity before the navigation can commence. On the quasi-stationary base, the self-alignment can be fulfilled with the high quality inertial sensors, and the fine alignment is usually executed to improve the alignment performance. Generally, fast estimating of heading misalignment is still a challenge due to the existence of gyro errors. An innovative data processing strategy called forward and backward resolution is proposed for INS initial alignment. The Rauch-Tung-Striebel (RTS) smoothing is applied to obtain the smoothed attitude estimates with the filter information provided by the forward data processing. The obtained attitudes are then treated as aiding measurements to implement the forward resolution with the repeated data set, the converged sensor biases are used as constraints, and the iterative processing is conducted to obtain the updated attitudes. Simulation studies have been conducted to validate the proposed algorithm. The results have shown that the alignment accuracy and convergence rate have been improved with the added RTS aided forward and backward resolution;more stable heading estimates can be obtained by calibrating with estimated gyro bias. A real test with a high quality inertial sensor was also carried out to validate the effectiveness of the proposed algorithm.
Thwarting severe cryptographic hardware attacks requires new approaches to logic and physical designs. This paper presents a systematic design approach to fault tolerant cryptographic hardware designs by combining the...
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Thwarting severe cryptographic hardware attacks requires new approaches to logic and physical designs. This paper presents a systematic design approach to fault tolerant cryptographic hardware designs by combining the concurrent error detection and correction, and uniform switching activity cells. The effectiveness of the Hamming code based error correction schemes as a fault tolerance method in stream ciphers is investigated. Coding is applied to Linear Feedback Shift Registers (LFSR) based stream cipher implementations. The method was implemented on industrial standard stream ciphers, e.g. A5/1(GSM), E0 (Bluetooth), RC4 (WEP), and W7. The performance of stream cipher algorithms with error detection and correction was studied by synthesising the designs on FPGA and custom Integrated Circuits. The hardware building blocks are investigated to minimise switching activity of a circuit for all possible inputs and their transitions by adding redundant gates and increasing the overall number of signal transitions. The overheads of the proposed approach are also discussed. (C) 2013 Elsevier Ltd. All rights reserved.
The article presents a method for preserving the privacy of individuals while simultaneously making data sets containing their private information available for statistical analysis. The concept of differential privac...
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The article presents a method for preserving the privacy of individuals while simultaneously making data sets containing their private information available for statistical analysis. The concept of differential privacy is said to offer a means of achieving statistical disclosure control, by randomizing responses in a way which preserves the accuracy of the data while dissociating it from the identity of any given individual. The hazards of auxiliary data, which can be used to indirectly ascertain redacted information, are noted, and the usefulness of pan-private algorithms is discussed.
The Saint-Venant equations of open-channel flow were linearized using the Taylor series and a finite-difference approximation of the original nonlinear, partial differential equations. Using the linear optimal control...
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The Saint-Venant equations of open-channel flow were linearized using the Taylor series and a finite-difference approximation of the original nonlinear, partial differential equations. Using the linear optimal control theory, a proportional-plus-integral (PI) controller was developed for an irrigation canal with five pools. Since the order of the controller gain matrix was large, the Kalman filter was designed to estimate values for the state variables that were not measured. For this problem, there were a total of 45 state and five control variables. With two flow depth measurements per pool, values for the remaining 35 state variables were estimated using the Kalman filter. The simulated canal dynamics with the regional PI controllers along with the local Kalman filter were compared with the performance of the global control algorithms for achieving a constant-volume control and a constant-level control of an example irrigation canal. The performance of the regional constant-volume control algorithms was found to be as good as the performance of the global control algorithm, whereas the performance of the regional constant-level control algorithm was marginally acceptable.
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