During the covid-19 pandemic, application of electronic teaching tools has emerged more crucial than ever. This research aimed at investigating impacts Flipgrid-based portfolio on EFL high school students’ speaking scores and their attitude towards use this e-portfolio. The study involved 86 students in Vietnam, which were divided two groups, a control an experimental one. data collected from p...

It is well known that some XML elements correspond to objects (in the sense of object-orientation) and others do not. The question we consider in this paper is what benefits we can derive from paying attention to such object semantics, particularly for the problem of keyword queries. Keyword queries against XML data have been studied extensively in recent years, with several lowest-common-ances...

We analyze the implications of short-selling and margin purchase constraints for management compensation and portfolio optimization under moral hazard. First, looking at the manager’s problem, we show that her active portfolio (that is, net of the benchmark) will not be independent of the benchmark design. We solve analytically for the benchmark composition that maximizes e¤ort expenditure. Ana...

Stock portfolio selection is a classic problem in finance, and it involves deciding how to allocate an institution’s or an individual’s wealth to a number of stocks, with certain investment objectives (return and risk). In this paper, we adopt the classical Markowitz mean-variance model and consider an additional common realistic constraint, namely, the cardinality constraint. Thus, stock portf...