Analytical characterisation and production of wool wax from Akkaraman and Morkaraman sheep's wool

The analytical characterisation and production of wool wax from Akkaraman and Morkaraman sheep in the East Anatolien region of Turkey have been investigated. It was shown that the analytical characteristics of Akkaraman and Morkaraman wool waxes differ only slightly from other wool waxes. Therefore, from a quality point of view, wool waxes obtained from this work can be used for the same purposes as wool waxes produced from different varieties of sheep.     

A practical power allocation method for multi-user and multi-carrier networks

Wireless Networks - In the majority of studies on wireless networks, it is assumed that the receiver perfectly knows the channel. Since this is not the case for real life applications, the channel...     

Correlation structure of training data and the fitting ability of back propagation networks: Some experimental results

White [6–8] has theoretically shown that learning procedures used in network training are inherently statistical in nature. This paper takes a small but pioneering experimental step towards learning about this statistical behaviour by showing that the results obtained are completely in line with White's theory. We show that, given two random vectorsX (input) andY (target), which follow a two-dimensional standard normal distribution, and fixed network complexity, the network's fitting ability definitely improves with increasing correlation coefficient r_XY (0r_XY1) betweenX andY. We also provide numerical examples which support that both increasing the network complexity and training for much longer do improve the network's performance. However, as we clearly demonstrate, these improvements are far from dramatic, except in the case r_XY=+ 1. This is mainly due to the existence of a theoretical lower bound to the inherent conditional variance, as we both analytically and numerically show. Finally, the fitting ability of the network for a test set is illustrated with an example.Nomenclature X Generalr-dimensional random vector. In this work it is a one-dimensional normal vector and represents the input vector - Y Generalp-dimensional random vector. In this work it is a one-dimensional normal vector and represents the target vector - Z Generalr+p dimensional random vector. In this work it is a two-dimensional normal vector - E Expectation operator (Lebesgue integral) - g(X)=E(Y¦X) Conditional expectation - Experimental random error (defined by Eq. (2.1)) - y Realized target value - o Output value - f Network's output function. It is formally expressed asf: R ^r×WR ^p, whereW is the appropriate weight space - Average (or expected) performance function. It is defined by Eq. (2.2) as (w)=E[(Yf(X,w)],w W - Network's performance - w ^* Weight vector for optimal solution. That is, the objective of network is such that (w ^*) is minimum - C ₁ Component one - C ₂ Component two - Z Matrix of realised values of the random vectorZ overn observations - Z _t Transformed matrix version ofZ in such a way thatX andY have values in [0,1] - X _t ,Y _t Transformed versions ofX andY and both are standard one-dimensional normal vectors - n _h Number of hidden nodes (neurons) - r _XY Correlation coefficient between eitherX andY orX _t andY _t - _s and _k in Eq. (3.1) and afterwards _s is average value of 100 differentZ _t matrices. _k is the error function ofkthZ _t , matrix. In Eq. (3.1), the summation is fromk=1 to 100, and in Eq. (3.2) fromi=1 ton. In Eq. (3.2)o _ki andy _ki are the output and target values for the kthZ _t matrix and ith observation, respectively - ^1/2(w ^*) and _k (w_n) k(w_n) is the sample analogue of ^1/2(w ^*) - _Y ² In Eq. (4.1) and afterwards, _Y ² is the variance ofY - _Y ² variance ofY _t . In Sect. 4.3 the transformation isY _t=a Y+b - Y _max,Y _min the maximum and minimum values ofY - R Correlation matrix ofX andY - Covariance matrix ofX andY - Membership symbol in set theory     

A new fuzzy logic estimator for reduction of commutation current pulsation in brushless DC motor drives with three-phase excitation

Under the operation of brushless DC motor with three-phase excitation, commutation current pulsation is produced at each commutation at high-speed region. As it can be eliminated when the current slew rates are made equal, a simple and effective fuzzy logic estimator (FLE) is presented first time in the literature to reduce such current pulsation. Its function is to simply regulate the commutation angle accurately to maintain the same current slew rates of commutated phases during commutation, thereby keeping the other phase current unchanged. Unlike previous studies, the presented method does not require torque observer or detection circuits for sensing commutation interval, in addition to commutation time calculation. A genetic algorithm is employed for optimal definition of the FLE’s rule base. The presented method is tested by the accurate simulation, and it is proved that the proposed method is quite capable of reducing the commutation current pulsation and improving the motor output power.

     

Augmented neural networks and problem structure-based heuristics for the bin-packing problem

In this article, we report on a research project where we applied augmented-neural-networks (AugNNs) approach for solving the classical bin-packing problem (BPP). AugNN is a metaheuristic that combines a priority rule heuristic with the iterative search approach of neural networks to generate good solutions fast. This is the first time this approach has been applied to the BPP. We also propose a decomposition approach for solving harder BPP, in which subproblems are solved using a combination of AugNN approach and heuristics that exploit the problem structure. We discuss the characteristics of problems on which such problem structure-based heuristics could be applied. We empirically show the effectiveness of the AugNN and the decomposition approach on many benchmark problems in the literature. For the 1210 benchmark problems tested, 917 problems were solved to optimality and the average gap between the obtained solution and the upper bound for all the problems was reduced to under 0.66% and computation time averaged below 33?s per problem. We also discuss the computational complexity of our approach.     

First application of symbiotic organisms search algorithm to off-line optimization of PI parameters for DSP-based DC motor drives

To enhance the performance and dynamics of a direct current (DC) motor drive, this paper proposes a new alternative based on recently introduced powerful symbiotic organisms search (SOS) algorithm for tuning proportional integral parameters. While imitating the symbiotic behavior that is seen among organisms in an ecosystem, SOS has important features such that it does not require tuning parameters, and its implementation is very easy with efficient three phases. After obtaining the optimized values of K _p  − K _i pair within the accurately prepared simulation software, they are used in real time. By managing the DC motor speed-controlled system with DSP of TMS320F28335, several simulations and experimental results confirming the performance of our proposal are presented along with comparisons against those of particle swarm optimization (PSO), genetic algorithm (GA), and Ziegler–Nichols (Z–N) tuning method. Results explicitly show that SOS is the pioneer in yielding better tracking performance and load disturbance rejection capability of the concerned drive system, which is followed by PSO, GA, and Z–N method, respectively. This has been achieved due to the fact that the gains obtained by SOS are more performant than those obtained by other applied methods.

     

Discharge Capacity of Labyrinth Side Weir Located on a Straight Channel

Side weirs, also known as lateral weirs, are flow diversion devices widely used in irrigation as a head regulator of distributaries and escapes, land drainage, and urban sewage systems. The studies on the subject have been generally focused on rectangular and triangular side weirs located on a straight channel. However, the same is not true for labyrinth side weirs. The current studies deal with sediment transport and scour problems around side weirs and lateral structures. The investigation of the hydraulic effects of labyrinth side weirs to increase discharge capacity of them has been studied in this particular work. In the study, 2,830 laboratory tests were conducted for determining discharge coefficient of labyrinth side weirs, and results were analyzed to find the influence of the dimensionless weir length L/b, the dimensionless effective length L/?, the dimensionless weir height p/h1, triangular labyrinth side weir included angle θ, and upstream Froude number F1 on the discharge coefficient, water surface profile and velocities in the channel along the side weir. It has been found that discharge coefficient of labyrinth side weirs gives pretty higher coefficient value compare to that of classical side weirs and a reliable equation for discharge coefficient of labyrinth weirs is presented. Discharge coefficient of the labyrinth side weir is 1.5–4.5 times higher than rectangular side weir.     

Effect of the particle size of fluorocarbon‐based finishing agents on fastness and color properties of 100% cotton knitted fabrics

This study examines the effect of the particle size of fluorocarbon‐based water‐oil‐soil‐repellent finishing agents on color fastness and colorimetric properties by experimental analyses. Therefore, two finishing agents with different particle sizes were applied to red‐dyed and blue‐dyed knitted fabric samples of single jersey and rib‐structured knits, produced from 100% cotton yarns. The results show that smaller particle size causes less color change for all washings (0, 1 and 5), both of the dyes and the fabric structures (single jersey and rib). Also, it is observed that smaller particle size positively affects the rub fastness results.     

Expectation–maximization‐based joint data detection and channel estimation for a cellular multi‐carrier code division multiple access network using single‐hop relaying

This paper is concerned with channel estimation and data detection for a cellular multi‐carrier code division multiple access network using single‐hop relaying in the presence of frequency selective fading channels. The proposed expectation–maximization (EM) algorithm was used to jointly estimate both the coefficients of the channel between a relay and a base station and the data. EM algorithm is particularly suited to multi‐carrier code division multiple access systems because they have multi‐carrier signal format. The considered network uses single‐hop relaying technique to provide a higher quality transmission to the users with low quality channels. The base station (managing mechanism) gives them an opportunity to send their messages via the users with high quality channels in a time sharing mode. The performance of the proposed EM algorithm, with and without hopping and with cooperative communication technique, was analyzed by a computer simulation, and the results are presented. Copyright © 2011 John Wiley & Sons, Ltd.     

The false positive effect of residue of sulphur sources on dithiocarbamate analysis based on CS2 measurement

Turkey plays an important role in the international trade of apricots as it has the largest production rate in the world. Since the sulphurisation process is allowed to be used for different products, the effect of residual sulphur and its compounds (which can be found in products as pesticide residues or additive residues) on the positive detection of carbon disulphide (CS₂) still creates a big challenge in international trade. Therefore, the main objective of the present study was to investigate the effects of residues of sulphur or sulphur compounds on dithiocarbamate analysis methods based on CS₂ measurement. In this study, apricots were chosen since they contain sulphur residues as a result of the sulphurisation process. Sulphur dioxide and dithiocarbamate analyses were conducted on dried apricots prepared with the sulphurisation process (SA) and without the sulphurisation process (NSA); analysis was by two different accredited laboratories. No of pesticide was applied to either SA or NSA samples. Although some of the NSA samples had <LOQ values, approximately 70 ± 32 mg/kg SO₂ and 0.061 ± 0.021 mg/kg dithiocarbamate were detected for NSA samples. On the other hand, for the SA sample group, 927–2915 mg/kg of SO₂ and 0.265–0.825 mg/kg of dithiocarbamate were detected. Furthermore, a strong correlation between residual sulphur and dithiocarbamate values was observed. This study showed that the analysis method based on CS₂ measurement may lead to false positive results for dithiocarbamates when residues of sulphur or sulphur compounds are found in products as pesticide or additive residues. Therefore, residual sulphur compounds as a result of the sulphurisation process (which is not considered during the evaluation of products) must be taken into account during the evaluation of products for dithiocarbamates.