Simultaneous scheduling of football games and referees using Turkish league data

Assignment decisions of referees to football (soccer) games are highly debated in sports media. Referee assignments are typically done on a weekly basis as the league progresses. However, this practice ignores important workload constraints on referees. Moreover, referees' skill levels should also be considered in determining their assignments. In this article, we first give a mixed integer linear program formulation for the problem of simultaneously generating a game schedule and assigning main referees to games by incorporating specific rules in the Turkish league. We also approach this problem using a genetic algorithm (GA) because of the computational difficulties in solving the problem. In the GA solution pool, we suggest using templates for referee assignments that follow several referee‐related workload constraints. We explain how these templates can be obtained by solving a mixed integer linear model prior to running the GA. The usage of these templates for referee assignments is conceptually similar to using a basic match schedule for game scheduling such as the one used in the Turkish Football League. We use the Turkish Football League fixtures for 2010–2013 as a case study. Experiments with the GA using real‐world data show a rather modest performance in terms of computation time and objective function value. Our numerical results indicate that the problem is extremely hard to solve.     

Evaluation of the shifting of the line of sight and higher order aberrations of eyes with keratoconus after corneal cross-linking

Aim

To evaluate changes in the coordinates of the line of sight (LoS) and higher order aberrations (HOAs) of eyes with keratoconus, following corneal cross-linking (CXL).

Performance evaluation of a submerged membrane bioreactor for the treatment of brackish oil and natural gas field produced water

Produced water, which is co-produced during oil and gas manufacturing, represents one of the largest sources of oily wastewaters. Therefore, treatment of this produced water may improve the economic viability and lead to a new source of water for beneficial use. In this study a submerged hollow fiber membrane bioreactor (MBR) has been studied experimentally for the treatment of brackish oil and natural gas field produced water. This type of wastewater is also characterized with relatively moderate to high amount of salt, oil and total petroleum hydrocarbons (TPH). However, the bacteria which are growing in conventional activated sludge and MBR cannot survive at these strict conditions, therefore acclimation of the bacteria is of vital importance. The performance of the biological system, membrane permeability, the rate and extent of TPH biodegradability have been investigated under different sludge age and F/M ratios. The results obtained by gas chromatography analyses showed that the MBR system could be very effective in the removal of TPH from produced water and a significant improvement in the effluent quality was achieved.     

A medico-legal evaluation of the use of assisted reproductive technologies in Turkey

In Turkey, as possibly in the case of several or even many other countries, infertility is generally regarded as a negative phenomenon in women. Assisted Reproductive Technologies (ARTs), which provide certain childless couples with the possibility of having a baby, are being applied more and more frequently in this country, apparently as has been the case in the world at large. From a medicolegal point of view, the related applications in Turkey can only be realized in the case of married couples. Other forms of application in this area, on the other hand, such as sperm banks or surrogate motherhood, are not allowed legally. A text which was called "Guidelines Regarding the Centers of In Vitro Fertilization and Embryo Transfer" was prepared in 1987 by the Ministry of Health. The aim of these Guidelines is to find solutions to the medico-legal problems created by the application of ARTs in this country.     

Inverse propagation of uncertainties in finite element model updating through use of fuzzy arithmetic

A fuzzy finite element model updating (FFEMU) method is presented in this study for the damage detection problem. The uncertainty caused by the measurement noise in modal parameters is described by fuzzy numbers. Inverse analysis is formulated as a constrained optimization problem at each α-cut level. Membership functions of each updating parameter which correspond to reduction in bending stiffness of the finite elements is determined by minimizing an objective function using a hybrid version of genetic algorithms (GA) and particle swarm optimization method (PSO) which is very efficient in terms of accuracy and robustness. Practical evaluation of the approximate bounds of the interval modal parameters in FFEMU iterations is addressed. A probabilistic analysis is performed using Monte Carlo simulation (MCS) and the results are compared with presented FFEMU method. It is apparent from numerical simulations that the proposed method is well capable in finding the membership functions of the updating parameters within reasonable accuracy. It is also shown that the results obtained by FFEMU are in good agreement with the MCS results while FFEMU is not as computationally expensive as the MCS method. Nevertheless, the proposed FFEMU do not required derivatives of the objective function like existing methods except in the deterministic case.     

A Two‐Sided Cumulative Sum Chart for First‐Order Integer‐Valued Autoregressive Processes of Poisson Counts

Count data processes are often encountered in manufacturing and service industries. To describe the autocorrelation structure of such processes, a Poisson integer‐valued autoregressive model of order 1, namely, Poisson INAR(1) model, might be used. In this study, we propose a two‐sided cumulative sum control chart for monitoring Poisson INAR(1) processes with the aim of detecting changes in the process mean in both positive and negative directions. A trivariate Markov chain approach is developed for exact evaluation of the ARL performance of the chart in addition to a computationally efficient approximation based on bivariate Markov chains. The design of the chart for an ARL‐unbiased performance and the analyses of the out‐of‐control performances are discussed. Copyright © 2012 John Wiley & Sons, Ltd.     

A fast minimization technique for subspace fitting with arbitraryarray manifolds

A new technique for minimization of a multidimensional subspace fitting criterion is proposed. An approximation is made to the exact criterion function, giving an explicit least squares solution for location parameters. Ideas from alternating projections are employed for initialization. The new technique gives global convergence with a high probability, has a low computational cost, is applicable to general array manifolds, and provides simple solutions for many problems with intricate parameterization     

Occurrence of aflatoxins (B1, B2, G1, G2) in herbal tea consumed in Turkey

Aflatoxin contents in 12 types of herbal teas were determined by high performance liquid chromatography (HPLC) with fluorescence detector using immunoaffinity column clean-up. Forty eight samples were collected from four local herbal shops in Manisa, Turkey. Of the 48 samples analyzed, 43 were aflatoxin positive. The highest concentration of aflatoxin (34.18 µg/kg) was determined in a sample of camomile tea. The occurrence of AFB1, B2, G1 and G2 was found in samples at levels of 54, 29, 71 and 46 %, respectively. Aflatoxin B1, B2, G1 and G2 contamination levels varied from 0 to 14.2, 0 to 12.4, 0 to 13.5 and 0 to 28.7 µg/kg, respectively. Aflatoxin was not detected in five samples consisting of linseed, lime and fennel tea.