Showing papers in "International Journal of Engineering - Transactions C: Aspects in 2013"

Designing Incomplete Hub Location-routing Network in Urban Transportation Problem

Abstract: In this paper, a comprehensive model for hub location-routing problem is proposed which no network structure other than connectivity is imposed on the backbone (i.e. Network between hub nodes) and tributary networks (i.e. Networks which connect non-hub nodes to hub nodes). This model is applied in public transportation, telecommunication and banking networks. In this model locating and routing is considered simultaneously and it has a multiple allocation strategy to allocate non-hub nodes to hub nodes. In addition, non-hub nodes can connect directly to each other. The objective of the proposed model is minimizing costs of establishing a network and transferring flows. To expedite solving the proposed model and improve the lower bound, which gain from linear relaxation, a number of preprocessing tests and valid inequalities are presented which have relatively good performance in the proposed model. Their performance is analyzed by implementing them on the test problems. Results show that using all preprocessing tests and valid inequalities is the best approach to solve the problem among all proposed approaches in this paper.

Comparing Three Proposed Meta-heuristics to Solve a New p-hub Location-allocation Problem

Abstract: This paper presents a new mathematical model, in which the location of hubs is fixed and their capacity is determined based on facilities and factories allocated to it. In order to feed the client's nodes, different types of vehicles of different capacities are considered, in which the clients are allocated to hubs, and types and numbers of vehicles are allocated to the factory's facilities. To come up with solutions we propose to use three meta-heuristics, namely genetic algorithm, particle swarm optimization, and simulated annealing. The efficiency and computational results of the foregoing algorithms are compared with one another. Finally, the conclusion is presented.

Performance Investigation of Multi-Phase VSI with Simple PWM Switching Techniques

Abstract: This paper presents the performance of multi-phase voltage source inverter (VSI) with simple PWM switching techniques, namely the harmonic injection and offset injection method. The technique discussed in this paper is easy to implement and avoid complicated controlling algorithm adapted in SVPWM technique. The generalized switching techniques are proposed in this paper. A generalized algorithm suitable for odd number of phases is developed in Matlab/Simuli nk environment and discussed in detail for both the switching methods. The performance of the 5, 7 and 9-phase VSI is studied with the above-said switching methods. The results of the simulation are presented for different modulation indices and a comparison in terms of fundamental voltage and THD identifies the better scheme suitable for multi-phase inverter fed drives.

Vibration Analysis of a Nonlinear System with a Nonlinear Absorber under the Primary and Super-harmonic Resonances (TECHNICAL NOTE)

Abstract: In vibratory systems, linear and nonlinear vibration absorbers can be used to suppress the primary and super-harmonic resonance responses. In this paper, the behavior of a nonlinear system with a nonlinear absorber, under the primary and super-harmonic resonances is investigated. The stiffnesses of the main system and the absorber are cubically nonlinear and the dampers are linear. Multiple time scales method is used to obtain approximate solution of the nonlinear equations of motion. Results show that at primary resonance, a linear absorber can suppress the peak amplitude of the system better than a non-linear one. But under super-harmonic resonance, the vibration amplitude can be more effectively reduced by adding a nonlinear absorber to the vibrating system.

Performance Analysis of a Repairable Robot Safety System with Standby, Imperfect Coverage and Reboot Delay

Abstract: The present study deals with a robot safety system composed of standby robot units and inbuilt safety unit. When the main operative unit fails, it is replaced by the standby robot unit available in the system. The concept of reboot delay is also incorporated in this study according to which the robot unit is rebooted if it is not successfully recovered. The recovery and reboot times of failed units, life time of the operative as well as standby units and the repair time are assumed be exponentially distributed. Furthermore, the repair time of partially-failed unit of total system failure is assumed to be arbitrarily distributed. The expressions for the state probabilities, availability, reliability and mean time to failure are derived with the help of Markovian and supplementary variable methods. The occurrence of standby units, imperfect coverage and reboot demonstrates the significant impact on the robot system reliability, availability and mean time to failure. A numerical illustration has been provided to validate the present model as well as to demonstrate the effects of various parameters on the performance measures of the robot safety system.

A Novel Design of Reversible Multiplier Circuit (TECHNICAL NOTE)

Abstract: Adders and multipliers are two main units of the computer arithmetic processors and play an important role in reversible computations The binary multiplier consists of two main parts, the partial products generation circuit (PPGC) and the reversible parallel adders (RPA) This paper introduces a novel reversible 4×4 multiplier circuit that is based on an advanced PPGC with Peres gates only Again, an optimized Peres full adder reversible gate is used in RPA part with accompaniment with the carry save adder technique The comparison of the proposed design with previous ones shows that the proposed reversible multiplier improves the quantum parameters The proposed design shows lower quantum cost, depth and total cost with the help of a novel design in partial product generator Moreover, the number of gates, garbage input and output has no change regarding to the best compared design The proposed multiplier can be generalized as an n×n bit multiplication

Discrimination of Power Quality Distorted Signals Based on Time-frequency Analysis and Probabilistic Neural Network

Abstract: Recognition and classification of Power Quality Distorted Signals (PQDSs) in power systems is an essential duty. One of the noteworthy issues in Power Quality Analysis (PQA) is identification of distorted signals using an efficient scheme. This paper recommends a Time–Frequency Analysis (TFA), for extracting features, so-called "hybrid approach", using incorporation of Multi Resolution Analysis (MRA) and Generalized S Transform (GST). Moreover, the proposed scheme is noticed to quality of features and ranking them in order to find the best combination with lower dimension. A new efficient feature ranking method namely Orthogonal Forward Selection (OFS) is applied for selection of the best subset features. Probabilistic Neural Network (PNN) as classifier is considered. An extensive series of simple and complex PQDSs are simulated to verify of suggested detection scheme. Also, sensitivity of the proposed method under different conditions of noise has been investigated. The obtained outcomes are compared with those obtained using other methods in previous research to assess the performance.

Simulation and Genetic Algorithms for Optimizing Comminution Circuit at Gol-e-Gohar Iron Plant (RESEARCH NOTE)

Abstract: simulation optimization is a scientific tool that is widely used to design and optimize comminution circuits in mineral processing plants. In this research, first of all, in order to determine the suitable d80 for cicuit hydrocyclone underflow, the requiremed parameters of simulator (residence time distribution, breakage function, selection function and Plitt’s model calibration) were determined. Then simulation of comminution circuit by presentation of BMCS software under MATLAB environment was performed. In the end, the GA toolbox of MATLAB software was used for optimization of the comminution circuit, by determining the simulator as fitness function. The results from this research showed that, by determining the optimum value of input parameters (solid perecent, fresh feed and water rate to the input streams), the genetic algorithm is able to achieve a suitable d80 for circuit cuf (cyclon underflow).

High Resolution Image with Multi-wall Carbon Nanotube Atomic Force Microscopy Tip (RESEARCH NOTE)

Abstract: In this paper, a simple and reproducible approach for attaching the multi-wall carbon nanotubes (MWNTs) to the apex of the atomic force microscope probe has been proposed. For this purpose, the dielectrophoresis method was applied due to its simple performance, cheapness and reliability. In this method, various parameters such as voltage, frequency, concentration of carbon nanotubes solution and tip\'s shape would affect the deposition of multi-walled carbon nanotubes on the probe of atomic force microscope. Here, specifically the voltage effect on the deposition of MWNTs onto the atomic force microscope tip has been investigated while the other parameters held constant. Our experiments revealed that when the frequency was held at 5 MHz and 1 µL of MWNTs solution injected, the optimum voltage between tip and electrode surface was 6 V.

Simulation and Experiment on Conveying Device of Cutting System of Small Sugarcane Harvester (RESEARCH NOTE)

Abstract: The main problem is less efficiency and blocking during sugarcane harvesting in hilly areas. This paper researched the cutting and transporting system of a small sugarcane harvester using virtual prototype technology. The dynamics simulation analyses were carried out to study the transporting status with different friction coefficients between the sugarcane and the spiral and different numbers of the rubber around the drum. The virtual test results show that increasing the friction coefficient can enhance the transporting speed of the sugarcane, and adding more rubbers on the drum can also increase the speed further. Then, the paper analyzed the logistic process of the cut sugarcane with different friction coefficients between the sugarcane and the spiral and four rubbers mounted on the drum based on the high-speed photography in the field simulation test. The results also show that the transporting speed of the cut sugarcane can increase 40% when the friction coefficient and the rubbers are added. The simulation and field test results verify that the virtual prototype technology can provide reference for the development of the physical prototype.

Use of Generalized Language Model for Question Matching

Abstract: Question and answering service is one of the popular services in the World Wide Web. The main goal of these services is to find the best answer for user's input question as quick as possible. In order to achieve this aim, most of these use new techniques foe question matching. We have a lot of question and answering services in Persian web, so it seems that developing a question matching model might be useful. This paper introduces a new question matching model for Persian. This model is based on statistical language model and employs generalized bigram and trigram model. We also describe some results regarding the employment of natural language processing in question matching model. Most of the QA hence we considered an optimized implementation for the model. We evaluated our model with Rasekhoon question and answering archive which contains about 18000 pairs of questions and answers. The results showed the improvement of precision and recall measures through using this model.

Preparation of Porous and Dense Bulk Samples in Calcium Magnesium Silicate Systems using Steel Slag and Different Additive by Conventional Sintering Method (TECHNICAL NOTE)

Abstract: In order to obtain the bulk brick-like samples, the mixture of steel slag, and sintering aid additive (like dolomite, glass, perlite borax and phosphate sodium) were sintered at 1100°C for 2 minutes. The flat and bloated surface appearances were obtained. The bulk densities of final sintered composites ranged from 1.3 to 2.41 g/cm and total porosities were from 15 to 40%. The bending strengths varied from 5.5 to 15.9 MPa. The final phase as detected by XRD according was calcium magnesium silicate doi: 10.5829/idosi.ije.2014.27.06c.11