Search

Synchrophasors, widely used in the monitoring and analysis of power systems, evolved from the phasor method presented by Charles Proteus Steinmetz in 1893. The phasor method is a mathematical method for solving linear sinusoidal steady-state circuits and time-varying electromagnetic fields. This paper traces the history and diffusion of the phasor method in the discipline of electrical engineering in China. In 1914, Sidney Roby Sheldon, an American teacher at the Government Institute of Technology of the Communications Ministry, Shanghai, China, introduced the phasor method to his students in his Alternating Currents course. The textbook used was Elements of Electrical Engineering (Volume II) by William Suddards Franklin and William Esty. In 1920, The Electrical Magazine published a paper “Complex number and its application” by Sijiu Shi (editor of the electrical engineering section of this periodical). This is the earliest example found of Chinese literature introducing the phasor method. In the 1930s, Principles of Alternating Currents, an American electrical engineering textbook that includes the phasor method, was translated by Chinese scholars; this Chinese version promoted the use of the phasor method in China's electrical engineering field. Alternating Current Circuits, authored by the Chinese university professor Pen Tung Sah and published in 1948, may be the earliest example of the phasor method being included in a Chinese electrical engineering textbook; it played an important role in popularizing the phasor method in China. [ABSTRACT FROM AUTHOR]

The computer science classes in China's institutions of higher education often have large numbers of students. In addition, many institutions offer "blended" classes that include both on-campus and online students. These large blended classrooms have long suffered from a lack of interactivity. Many online classes simply provide recorded instructor lectures to which distance students listen after downloading. This format only reinforces the negative effects of passive nonparticipatory learning. At a major university in Shanghai, researchers and developers actively seek technological interventions that can greatly increase interactivity in blended classes. They have developed a cutting-edge mobile learning system that can deliver live broadcasts of real-time classroom teaching to online students with mobile devices. Their system allows students to customize their means of content-reception, based on when and where the students are tuning into the broadcast. The system also supports short text-messaging and instant polls. Through these features, students can ask questions and make suggestions in real time, and the instructor can respond immediately. This paper describes this system in detail and also reports results from a formal implementation of the system with a blended classroom of 562 students (of whom 90% were online). [ABSTRACT FROM AUTHOR]