A polynomial time algorithm for Harder-Narasimhan filtrations of representations of acyclic quivers

We establish a deterministic polynomial time algorithm for computing the Harder-Narasimhan filtrations of representations of acyclic quivers. As an application, we also show that Kempf's maximally destabilizing one parameter subgroups of an unstable representation over an algebraically closed field can be obtained within polynomial time complexity

Enhancing classroom management through parental involvement by using social networking apps

The purpose of this study is to explore the classroom management effectiveness enhancement by using social networking apps through electronic devices such as smartphones, tablet computers, and personal computers, as well as the role of parental involvement. Quantitative research was conducted, and the Structural Equation Modelling (SEM) statistical technique applied. From 15 different Changhua County primary schools in Taiwan, 411 teachers were chosen using stratified random sampling in proportion to the size and location of schools. Each teacher was invited to fill out a questionnaire. A total of 403 (98.05%) questionnaires were returned, with 382 (92.94%) considered valid. In order to confirm the statistical results, a focused group interview was also conducted. The effects of the behaviour intention of using Line, parental involvement, and classroom management effectiveness were all found to be positively associated with one another. Moreover, the mediating role of parents in the relationship between the behaviour intention of using Line and classroom management effectiveness enhancement was also supported and confirmed.Keywords: behaviour intention; classroom management effectiveness; parental involvement; social networking apps; Taiwan’s primary school

Improved Antireflection Properties of an Optical Film Surface with Mixing Conical Subwavelength Structures

Based on finite difference time domain method, an optical film surface with mixing conical subwavelength structures is numerically investigated to improve antireflection property. The mixing conical subwavelength structure is combined with the pure periodic conical subwavelength structures and the added small conical structures in the gap between the pure periodic conical subwavelength structures. The antireflection properties of two types of subwavelength structures with different aspect ratios in spectral range of 400–800 nm are analyzed and compared. It is shown that, for the mixing type, the average reflectance is decreased and the variances of the reflectance are evidently smaller. When the added structure with a better aspect ratio exists, the average reflectance of the surface can be below 0.30%. Obviously, the antireflection properties of the optical film surface with mixing conical subwavelength structures can be improved

Productivity Change in Taiwan's Farmers' Credit Unions: A Nonparametric Risk-Adjusted Malmquist Approach

This article proposes an extended three-stage DEA methodology similar to Fried et al. (2002) to improve the measurement of productivity growth then the assumption of free disposability of undesirable outpu t does not apply. A directional distance function is used to construct adjusted Malmquist-Luenberger productivity indexes which simultaneously account for the impacts of undesirable outputs, environmental variables, and statistical noise. Panel data for 264 farmers' credit unions (FCUs) in Taiwan covering the 1998-2000 period are employed to illustrate the advantages of this method. On average, the productivity of Taiwan's FCUs is found to have deteriorated over the 1998-2000 period. Although an improvement in efficiency has been observed, the major reason for the deterioration is found to be due to the regression of techno logy.Malmquist-Luenberger productivity index, three-stage DEA, undesirable outputs, directional distance function, Agricultural Finance, Productivity Analysis,

Ride responses of macpherson suspension systems

The main purpose of this study is to obtain more correct vehicle ride responses by using a nonlinear ride model considering the effect of Macpherson suspension geometry. Traditional ride model applied to analysis and controller design uses a two degree of freedom linear model, which includes sprung mass and unsprung mass and a spring and a damper vertically connect them. In fact, suspension components do not vertically position above the tire. The motions of body and tire are not going straight up and down. Therefore, the analysis results obtained by the simple model are often different from the experimental values of the actual vehicle. Because of the difference between simple model and actual vehicle, the control strategy almost cannot apply to actual vehicle. In order to understand the effect of suspension geometry on the vehicle ride responses and design a more practical control strategy, a nonlinear model including the geometric parameters of the suspension is constructed in this study. To estimate the initial equilibrium position of the suspension assembly under load, the static equilibrium analysis and mechanism motion analysis are synchronous implemented at the same time. The nonlinear model describes not only the relative position and velocity but also the force transmission between body and tire. Furthermore, by linearize this nonlinear model the development of control strategy for subsequent (semi) active suspension system could be expected

Determinants of consumer behavior toward counterfeit products: involvement and the attitude toward brand equity

Counterfeits, unauthorized copies of a product presented for sale as if they were the legitimate manufacturer's product, are creating a sizeable and growing problem for the apparel and accessory industries (Olsen & Granzin, 1993). The purpose of the study was to investigate the relationship between consumers' likelihood of knowingly purchasing counterfeit products and their involvement characteristics (consumer involvement with purchasing activity, hedonic goods, brand name, fashion trend, and brand's country of origin). Relationships between their likelihood of knowingly purchasing counterfeit products and the attitude toward brand equity were also investigated. In this study it was found that there were no significant relationships between consumers' likelihood of knowingly purchasing counterfeit products and their involvement with purchasing activity, hedonic goods, brand name, fashion trend, and brand's country of origin. Also, consumers' likelihood of knowingly purchasing counterfeit products and their attitude toward brand equity was not significantly related. So, it was thought that counterfeit product is a contradiction. The dilemma makes consumers fall in contradiction when finding relationships between their willingness to purchase counterfeit goods and their involvement characteristics, and the attitude toward brand equity