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,

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

A Temporal Usage Pattern-based Tag Recommendation Approach

While social tagging can benefit Internet users managing their resources, it suffers the problems such as diverse and/or unchecked vocabulary and unwillingness to tag. Use of freely new tags and/or reuse of frequent tags have degraded coherence of corresponding resources of each tag that further frustrates people in retrieving information due to cognitive dissonance. Tag recommender systems can recommend users the most relevant tags to the resource they intend to annotate, and drastically transfer the tagging process from generation to recognition to reduce user’s cognitive effort and time. Prior research on tag recommendation has addressed the time-dependence issues of tags by applying a time decaying measure to determine the recurrence probability of a tag according to its recency instead of its usage pattern. In response, this study intends to propose the temporal usage pattern-based tag recommendation technique to consider the usage patterns and temporal characteristic of tags for making recommendations