In a realistic steady-state visual evoked potential (SSVEP) based brain-computer interface (BCI) application like driving a car or controlling a quadrotor, observing the surrounding environment while simultaneously gazing at the stimulus is necessary. This kind of application inevitably could cause head movements and variation of the accompanying gaze fixation point, which might affect the SSVEP and BCI’s performance. However, few papers studied the effects of head movements and gaze fixation switch on SSVEP response, and the corresponding BCI performance. This study (...) aimed to explore these effects by designing a new ball tracking paradigm in a virtual reality (VR) environment with two different moving tasks, i.e., the following and free moving tasks, and three moving patterns, pitch, yaw, and static. Sixteen subjects were recruited to conduct a BCI VR experiment. The offline data analysis showed that head moving patterns [F(2, 30) = 9.369, p = 0.001, effect size = 0.384] resulted in significantly different BCI decoding performance but the moving tasks had no effect on the results [F(1, 15) = 3.484, p = 0.082, effect size = 0.188]. Besides, the canonical correlation analysis (CCA) and filter bank canonical correlation analysis (FBCCA) accuracy were better than the PSDA and MEC methods in all of the conditions. These results implied that head movement could significantly affect the SSVEP performance but it was possible to switch gaze fixation to interact with the surroundings in a realistic BCI application. (shrink)

Studies on the chronology of ancient books are a form of basic research. They involve complex causes and factors that have to do with the formation of ancient books, include many of the mysteries and secrets of hermeneutics, and are a matter that deserves repeated study and research. In the past, the "doubting of antiquity" school of thought viewed ancient books with an attitude of universal skepticism, which might well be described as an overall rethinking with regard to ancient books, (...) and which directly affected people's entire cognition of China's ancient civilization. In recent years, however, in the wake of the increasing numbers of archaeological discoveries and deeper studies into ancient history, a change is fermenting in people's views about the chronology of ancient books. Due to geographical proximity and convenience in obtaining materials, a number of scholars on the Chinese mainland are already strongly aware of this change. For instance, Li Xueqin has time and again written articles proposing that a "second rethinking" should be conducted with regard to ancient books.1 However, up to this day, many people have yet to attach sufficient importance to this change . I am therefore raising this issue and conducting a preliminary analysis from all the aspects that it touches upon. (shrink)