Aberration in qualitative multilevel designs

Generalized Word Length Pattern (GWLP) is an important and widely-used tool for comparing fractional factorial designs. We consider qualitative factors, and we code their levels using the roots of the unity. We write the GWLP of a fraction ${\mathcal F}$ using the polynomial indicator function, whose coefficients encode many properties of the fraction. We show that the coefficient of a simple or interaction term can be written using the counts of its levels. This apparently simple remark leads to major consequence, including a convolution formula for the counts. We also show that the mean aberration of a term over the permutation of its levels provides a connection with the variance of the level counts. Moreover, using mean aberrations for symmetric $s^m$ designs with $s$ prime, we derive a new formula for computing the GWLP of ${\mathcal F}$. It is computationally easy, does not use complex numbers and also provides a clear way to interpret the GWLP. As case studies, we consider non-isomorphic orthogonal arrays that have the same GWLP. The different distributions of the mean aberrations suggest that they could be used as a further tool to discriminate between fractions.Comment: 16 pages, 1 figur

The effect of exercise intensity on decision making performance of experienced and inexperienced soccer players.

The aim of this study was to examine the decision making performance of experienced and inexperienced soccer players at four different exercise intensities: rest, 40% maximal aerobic power (moderate exercise I), 60% maximal aerobic power (moderate exercise II) and 80% maximal aerobic power (high intensity exercise). Following Easterbrook’s theory, for the novice players it was predicted that the decision making accuracy and speed of decision making would show an inverted-U shape with increasing levels of exercise. For the experienced players, due to the automaticity of information processing, speed and accuracy of decision making were predicted to show no change in performance with increased exercise intensity. Thirty-two subjects, 16 experienced and 16 inexperienced adult male soccer players, participated in the study. Subjects were required to answer seven decision making questions at each exercise intensity. Level of soccer experience and level of exercise intensity were the independent variables while accuracy and speed of decision making were the dependent variables of this study. The data were analyzed using a 2 (experienced and inexperienced players) X 4 (exercise intensity level) multivariate analysis of variance with repeated measures on the last factor. The results indicated that exercise does not affect accuracy of decision making however there was a difference between experienced and inexperienced players. The effects of exercise intensity on speed of decision making for experienced and inexperienced players showed improved speed of decision making at moderately-high and high intensity exercise. Results of this experiment do not support the inverted-U hypothesis. </p

Combinatorial Analysis of Factorial Designs with Ordered Factors

In recent literature a new combinatorial algorithm for the selection of robust fractional factorial designs has been introduced. In this work we analyze the application of this algorithm in the case of ordered factors

Robustness of Fractional Factorial Designs through Circuits

Given a model, we define the robustness of an experimental design as a function of the number of estimable minimal sub-fractions of it. We show how the circuit basis of the design matrix can be used to see if a minimal fraction is estimable or not and we describe an algorithm for finding robust fractions

Effect of Surface Stability on Core Muscle Activity for Dynamic Resistance Exercises

To compare core muscle activity during resistance exercises performed on stable ground vs. the BOSU Balance Trainer. Methods: Twelve trained men performed the back squat, dead lift, overhead press, and curl lifts. The activity of the rectus abdominis, external oblique abdominis, transversus abdominis/internal oblique abdominis, and erector spinae muscles was assessed. Subjects performed each lift under three separate conditions including standing on stable ground with 50% of a 1-RM, standing on a BOSU Balance Trainer with 50% of a 1-RM, and standing on stable ground with 75% of a 1-RM. Results: Significant differences were noted between the stable 75% of 1-RM and BOSU 50% of 1-RM conditions for the rectus abdominis during the overhead press and transversus abdominis/internal oblique abdominis during the overhead press and curl (P \u3c .05). Conversely, there were no significant differences between the stable 75% of 1-RM and BOSU 50% of 1-RM conditions for the external obliques and erector spinae across all lifts examined. Furthermore, there were no significant differences between the BOSU 50% of 1-RM and stable 50% of 1-RM conditions across all muscles and lifts examined. Conclusions: The current study did not demonstrate any advantage in utilizing the BOSU Balance Trainer. Therefore, fitness trainers should be advised that each of the aforementioned lifts can be performed while standing on stable ground without losing the potential core muscle training benefits

Haptic Hand Exoskeleton for Precision Grasp Simulation

This paper outlines the design and the development of a novel robotic hand exoskeleton (HE) conceived for haptic interaction in the context of virtual reality (VR) and teleoperation (TO) applications. The device allows exerting controlled forces on fingertips of the index and thumb of the operator. The new exoskeleton features several design solutions adopted with the aim of optimizing force accuracy and resolution. The use of remote centers of motion mechanisms allows achieving a compact and lightweight design. An improved stiffness of the transmission and reduced requirements for the electromechanical actuators are obtained thanks to a novel principle for integrating speed reduction into torque transmission systems. A custom designed force sensor and integrated electronics are employed to further improve performances. The electromechanical design of the device and the experimental characterization are presented