the purpose of this study was to evaluate the rate of using standards of designing electronic courses in educational contents of state-virtual universities in iran. the method of the study was a descriptive-survey one. the statistical population was the educational content of electronic courses in state-virtual universities such as university of science and technology, and shiraz university. da...

This paper proposes improvements and revisions to a recent approach in a voting system, and provides an effective approach with a stronger discriminate power. For this purpose, the advantage of a linear transformation is utilized to redene a previously used concept of virtual worst candidate, by incorporating the existing weight restrictions. Then, the best score of this virtual candidate is us...

with the advent of e-commerce, organizations are changingtheir business. most researchers believe that electronic trading can besuccessful when the public will trust in virtual environments. high degreeof confidence not only can meet customer expectations of a satisfactorytransaction, but can also eliminate certainty and perceived risk of onlinetransactions. the aim of this research is to study...

This paper suggests a new control method to modify the virtual impedance performance in unbalanced conditions. The proposed method compensates the voltage drop that occurred due to the virtual impedance and adjusts the voltage of the point of common coupling at a desirable level. To compensate the voltage drop, the reference voltage in the droop control varies according to the proposed algorith...

This paper proposes the virtual flux based direct power control for Vienna rectifier. No need for the input voltage sensors, the current regulation loop and PWM voltage modulation block along with the active and reactive power decoupling are some of the salient advantages of this method that make it suitable for controlling the conventional active rectifiers. However, due to the three-level nat...

writing has always been considered an important literacy skill for foreign/second language learners. the internet provides such unique applications for the writing skill as weblogs, wikis, and social networking websites. up to now researchers have put their focus on the learners’ performances in the traditional paper and pencil environment or wikis and blogs it is time to also consider learners...