Effect of Flipped Teaching on Cognitive Load Level with Mobile Devices: The Case of a Graphic Design Course

: Due to the emergence of computer education, AI education, the Internet of Things, big data, and technological wisdom, it is easy for students to be distracted when engaged in traditional education. Flipped teaching is a teaching strategy frequently used in colleges and universities. The focus of this research was conducted by a comparative analysis of the cognitive load between the experimental group and the control group through a quasi-experimental design for research with different learning methods and different classes. More speciﬁcally, ﬂipped teaching was carried out with an experimental group, and traditional teaching a control group; they were observed at the same time, and 213 private university students participated in the experiment. The research proposes a practice of mixed teaching, carried out in a group communication behavior system, and enhancing the spirit of group interaction and learning through mobile devices. The core value of the research lies in (1) online learning, (2) group interaction, and (3) the learning load of the conceptual model. In addition, focus group interviews were used to provide feedback on participants’ cognition and emotions. The results indicate that there were differences in cognitive load between the two classes.


Introduction
Online learning has been widely used in recent years. It has gradually become a common teaching method in formal and informal education environments [1], such as Massive Open Online Courses (MOOC), Small Private Online Courses (SPOC), TronClass, etc. [2]. These learning platforms not only support multiple application scenarios, such as "learning management", a "flipped classroom", and "smart classrooms", but also provide an interactive teaching experience [3]. The TronClass Online Learning Platform (TOLP) uses wireless mobile communication network technology and operates through evaluation, analysis, execution, and synthesis. It provides learners with new opportunities for active learning and uses active and autonomous pre-class video learning for learners to get a preview before class. Since the invention of the smartphone, technology has allowed people to rely on Internet information and computerization more and more. However, based on the global reliance on online learning, TOLP has also been used on campuses for network teaching. TOLP has the advantages of no time limit and no regional learning limit. It helps learners use fragmented time to promote independent learning. Nevertheless, before the introduction of the full potential of TOLP, mobile learning needs to be integrated into the most suitable situation to fit the formal education environment. However, video-based learning with flipped teaching can help improve students' academic performance [4].
In reviewing past studies, we see that Goal 4 of the UN Agenda 2030 sustainable development goals (SDG) is aimed at working towards quality education. Colleges and universities have an important role to play in teaching sustainability principles [5]. Although most experts believe that the existence of teachers is irreplaceable, there will still be many changes in the work of teachers and the best practices of AI smart education and interdisciplinary partnerships [6]. In this research, TOLP was carried out on an experimental group in September 2019. Currently, this learning platform is rarely used, according to the surveyed literature. We have used a graphic design course (GDC) as an example. It is assumed that there is no significant difference between the practice of flipped teaching and traditional teaching methods. That explains why video teaching can be used to acquire knowledge, through data verification. Learners can learn autonomously and construct a domain of knowledge. This is, thus, a better learning method than traditional teaching tools (textbooks, oral delivery of knowledge, whiteboards, chalkboards, and briefings). This research focuses on learning cognition with the flipped teaching method and the interaction between cognitive loads.

What Is a Flipped Classroom?
The current environment shows a trend towards emphasizing multitasking and social learning. The enhancement of digital experience has become a daily part of the learning habits of a new generation of students [7]. There is evidence that millennial students (born between 1981 and 1996) are inclined to use technology as a tool to obtain new knowledge [8]. However, "flipped teaching" was promoted as early as 1999, by MIT's "Internet teaching course". At that time, teachers had the tendency to transfer their knowledge material online and launched Open Course Ware (OCW) free open online courses the following year. It is used by institutions, students, and self-learners in various parts of the world [9]. "Flipped classroom" is a term for letting learners preview the contents of the classroom teaching when they are outside the classroom. It is a teaching model that involves pre-class preparation and interactive participation in the classroom.
In recent years, many educational researchers and educators have tried to use the "flipped classroom" concept to solve problems that learners experience in the classroom. First of all, the teacher solves the problem of absence among secondary students by recording a short video of 4 to 6 min. When students miss a lecture, they can view the video lecture afterwards. It can also be used to review the main points of the class at home. However, teachers realized that some students would be to give up doing their homework, and let them try to find the answers in the video [10]. New teaching methods mean that students who do not like homework can increase their motivation to learn independently and can make fuller use of resources and time. The flipped classroom approach has, therefore, become one of the most well-known instructional approaches in recent years. If appropriate educational tools and methods are not provided to support students, their learning performance may not be as good as expected. Therefore, this highlights the importance of flipped classrooms [11].

Benefits of Flipped Teaching
In an era of technological overload, educators have observed that it is increasingly difficult for learners to pay attention to traditional lectures. Therefore, educators must be to shift away from traditional teacher-centered classroom lectures to student-centered teaching methods. These will incorporate more diverse, cross-domain materials. Recently, many educators have begun to question traditional teaching, although the lecture format is still the main teaching method for adult learners [12]. If the goal of teaching is to improve students' understanding, we can see that the past method of enforcing the memorizing of knowledge encourages a kind of "surface learning" [13]. Students spend time in class to study problems, have discussions, put forward ideas, and participate in collaborative learning (CL) [10]. To achieve this goal, educators try to use online video lectures to pre-record teaching materials before class and assign homework. Thereafter, students can discuss and undertake interactive learning activities during class time. Cooperative learning and discussion in the "flipped classroom" are regarded as important learning activities. The principle of peer-assisted learning and the cooperative learning theory are new concepts in science and technology that can assist with education in the, so-called, "flipped classroom" [14,15].
A list of subjects suited to computer-assisted instruction (CAI) [16] has been developed, including textiles, graphic design, clothing construction, and the visualization of three-dimensional designs from two-dimensional patterns. CAI modules can be used by teachers to guide students in limited classroom time, and can be a learning method that suits the individual's skill level or project needs. For example, the implementation of a flipped classroom in a clothing construction context allows students and teachers to focus their classroom time on skill development, problem-solving, and active learning while performing homework. It can also be inferred that the flipped classroom has advantages over classroom explanation. Similarly, experimental research was conducted using CAI modules combined with traditional classrooms in university courses. The results showed that students like to use CAI and have improved knowledge acquisition, so they [17][18][19] get a mixed-method education and show improved academic performance. Some studies [11] have indicated that students involve in collective problem-solving in a promotion-based flipped classroom not only have better learning performance and collective efficacy, but also a higher level of knowledge construction and deeper interactions. These studies can be a reference for orientation of future teaching and research.
The "flipped classroom" is an innovative teaching method that relies on digital video and practical problems given as homework. The group's active learning and use of advanced information technology will produce a new direction for educational research. This represents a major difference from the traditional approach of delivering lectures first, and assigning practice and problem-solving after class. Flipped teaching focuses on collective interaction and problem solving in the classroom. Video lectures, quizzes, and exercises are used as the course model before class [20]. In "The flipped classroom: A survey of the research" [21], college students viewed online video lectures, which were considered better than live lectures, and interactive online videos were considered even better (effect size = 0.5). Students [10] think video lectures are the better choice. The research adopts formal or informal online teaching. Although the research reveals some differences, student perceptions are relatively consistent and often positive. Only a small number of students do not like the change.

Defining of the Flipped Classroom
What is the impact of pre-class video teaching on flipped classrooms of learners? Many videos created by teachers are of questionable quality and require a lot of time and resources. Nowadays, college students in higher education participate in flipped classrooms. They use field notes, interviews, and focus groups in an introductory statistics course, compared with a traditional introductory statistics course at the same university. The results show that the students in the flipped classroom are not satisfied with the adaptation of the teaching structure and their learning tasks, but the students are still willing to accept cooperative learning and innovative teaching methods [22]. "Considerations about Flip Education in the Teaching of Advanced Mathematics" indicated that, parallel to the social transformation, there is a transformation of information and communication technologies (ICT). ICT has already undergone important developments, accompanied by a clear reduction in costs and increased ease of use of different tools to create and edit quality videos, with the possibility of disseminating them on a network [23]. Some scholars have proposed that technology and innovation empower higher educational institutions (HEI) to execute different teaching and learning systems. These online interactions are useful for understanding the effectiveness of this kind of learning [24].
In the past, it was emphasized that educators are always experimenting, using innovative teaching methods, and developing effective learning materials and resources. Good teaching should arouse the learning motivation of the student, and active participation is necessary. Success at arousing student aptitude and interest is determined by the inclusion of moving and interesting stories [20]. Teaching in a flipped classroom can involve case studies, active learning in the classroom, experiments, games, simulations, and discussion. It also covers automatic tutorials, team learning, peer guidance, inquiry learning, instant teaching, mixed classrooms, mixed courses, and process-oriented guided inquiry learning (POGIL) [25]. In [26], the classroom response system (CRS) was mixed with the flipped classroom (FC) and team-based learning (TBL) to provide a super-mixed teaching model. These strategies can help learners to think critically and strengthen their abilities. Unfortunately, they require a high pay-off. Some researchers [21] have shown that the flipped classroom is meant to attract the interest of students through video teaching, and proposed that student-centered active learning be combined with lectures to solve problems. Therefore, researchers have explored the distinctions between "flipped teaching" and "traditional teaching", as shown in Table 1.

Role of Cognitive Load in Learning
Human memory can be divided into short-term memory (STM) and long-term memory (LTM). It is used to log, store, and retrieve memories. Short-term memory refers to the conversion of information into memory after about 20 s, and most of it uses auditory and verbal triggers to enhance the learner's memory [27]. The storage capacity for information is quite limited. However, the interaction of elements in storage requires working memory space. Long-term memory is the result of continuous practice before the short-term memory disappears. It may involve some small, fragmented, complex, and serialized human cognitive activities. Learners can transform certain perceptual features into concepts or meaningful coding forms, practice retelling, and, thereby, turn them into long-term memory. Long-term memory is the basis of learning and requires learning in a lasting sense [28]. Well-organized information can reduce the load of learning on working memory, and the tolerance of each learner to the learning load may also be different.
There are three types of cognitive load (CLT): (1) intrinsic cognitive load, (2) extraneous cognitive load, and (3) germane cognitive load [29]. Under the interaction of elements, the demand for working memory and learning materials is the first type of load. The presentation of different materials or the complexity of the task may also cause differences in load. Of course, simple learning materials and tasks, which pose a smaller relative burden, are important. However, materials with highly complex elements are unavoidable [30]. In the second category, extraneous cognitive load, the presentation of teaching materials and the information organization will affect the learner's process of absorbing knowledge. In addition to the normal teaching process, an additional cognitive load may be generated. Moreover, the difference in level of students in the class may also lead to different adaptability when absorbing knowledge. If extra irrelevant or ineffective materials and resources are added in the process, it may cause problems with the learning and understanding of learners [31].
Therefore, it is important to design usable instructional design and procedures to reduce unnecessary cognitive load [32]. Germane cognitive load is the final type of instructional design and attracts learners to focus on the cognitive process of learning content. When learning motivation is enhanced, the tasks of cognitive resources are increased simultaneously [31]. The effective cognitive load is also improved. The total cognitive load cannot exceed human mental resources. Therefore, in experimental research, a more effective teaching design is usually used to reduce irrelevant cognitive load and improve learning [33].

Cognitive Load Measurement Methods and Changes
The measurement of the cognitive load was undertaken in the early stage of the evaluation of experimental design. We conducted the experimental research through two groups to understand their differences [34], and, particularly, to evaluate the problemsolving ability of the two groups. The variables to use to judge cognitive load were differences in test scores, teaching hours, and error rate. Moreover, it was recognized that earlier "classifications of cognitive load" were carried out through NASA's Task Load [35]. The development and research of NASA-TLX obtained a subjective evaluation of 10 workload-related factors from 16 different experiments (experimental tasks include: cognition, manual control, supervisory control tasks, aircraft simulation, etc.). This task divides cognitive load into 10 categories, including overall workload, work difficulty, time pressure, performance, mental/perceptual effort, physical effort, frustration, stress, fatigue, and behavior types. The research by Chen [36] divides NASA's task load into mental demand, physical demand, temporal demand, effort, frustration level, and performance categories (see Table 2).

Cognitive Load in Online Learning
The purpose of teaching is "meaningful learning". If the effectiveness of teaching is not good, then the teaching will be meaningless [37]. In the past, many educators have made great contributions to the research into cognitive load. Researchers have also put forward hypothetical cases for reducing the load on working memory, successfully reducing extraneous cognitive load, and releasing memory capacity to increase the load. Afterward, dynamic methods began to appear in instructional design [33]. These provide researchers with a new cognitive load development opportunity by using instructional control to Sustainability 2021, 13, 7092 6 of 26 manipulate the way cognitive load interacts with objects. As the professional level of learners improves, these technologies will change their cognitive load to create a kind of knowledge reversal effect. This shows that cognitive load has a reasonable theoretical explanation [30]. Most learners [36] in a multimedia environment will encounter cognitive load in learning when they deal with the complexity of text and picture presentations. In the past, scholars have proposed that evaluating cognitive load also helps us to adjust learning tasks in an online environment. The authors tested five overloaded multimedia cognitive situations. However, multimedia learning is generally effective for promoting the learning of individual tasks.
At the psychological level, teaching demonstration materials have also become an important part of the cognitive structure. In this way, researchers use problem-solving transfer tests to measure learning results [38]. At the same time, educators are aware that a major challenge that multimedia instructional design must face is the possibility of cognitive overload [36]. Researchers [38] have tried to solve this difficulty in their research by employing an unfamiliar material environment the assumption being that, when students do not have enough time to participate in the module, this high-load learning mode may make them unable to digest and move on to the next stage. They were used complicated teaching materials and unknown training as a guide for teaching through the construction of psychological modules. They also deleted the redundant external load material in the teaching demonstration. In the laboratory, students learn from synchronized teaching demonstrations and perform better than in the problem-solving transfer test. Research has shown that synchronous teaching can reduce cognitive load. The researcher calls this result the effect of time continuity. Therefore, [39] how to reduce cognitive load has become an important topic for educational researchers and educators. Meaningful teaching [37] entails many cognitive processing, but the cognitive resources of learners in information processing are greatly restricted. Therefore, in the application of classroom teaching design, unnecessary cognitive load needs to be avoided as much as possible to achieve an effective reduction in cognitive load.

AI Used in Education and Sustainable Learning
Nowadays, educators, psychologists, and parents are most concerned about the time that students or children spend using screen. This kind of emerging technology appears in the form of artificial intelligence education and machine learning, and it will change the environment of future learning and education. The "Artificial Intelligence Market in the U.S. Education Field" reports that the U.S. predicts and analyzes the growth of 49.22% in artificial intelligence in 2021-2025 and the global effects of the COVID-19 pandemic [40]. When various factors make it impossible to conduct regular education, online learning in AI intelligence can fill the gap in the needs of teaching and learning [41]. For many years, especially with class management in private schools, teachers have had to face the educational management of the individual special needs of 60-70 students in each class. The degree of differentiation of the learners themselves makes it difficult for teachers to operate. Therefore, it is relatively important to provide learners in smart education and digital platforms. For artificial intelligence, it can help break down silos between schools and between traditional grades [42]. However, for most parents, supporting AI education is very excited about their children's counseling and remedial plans. Moreover, it shows the importance of AI instructor's communication method and social existence [43].
In the future, AI education [42] can help open classrooms around the world to everyone. With the development and innovation of machinery and equipment, for other special functions, such as: visual or hearing impaired of functional facilities, students who cannot go to school due to illness, etc. Even in the future, the learner may have facial expressions through machines, which can immediately return the teacher's attention. The recent development of artificial intelligence and big data technology will promote the rapid transformation of e-learning systems and applications into a new era, e-learning 4.0 [44].
Artificial intelligence (AI) has considerable potential in the future education vision, and is regarded as a sustainable educational tool.

Materials and Methods
Considering the popularization of AI education and the use of the Internet in modern society, it is clear that the constraints of time and space have already been broken. Recently, some universities have begun to implement TOLP as a learning method. In the past, some scholars [45] (2013) have indicated that learning in the beginning and bottleneck stages of learning can be guided by extrinsic motivation. Once students become autonomous learners, extrinsic incentives become unnecessary. Intrinsic and extrinsic motivations complement each another. Learning motivation and external motivation are affected by (1) learning performance, (2) teacher rewards, and (3) the professional skills acquired. These become the motivation for learners to learn independently, and they will be obtained through some incentive measures. Therefore, learning motivation serves as an intermediary between stimulation and learning.
It is more and more common, especially among private university students, for a lack of learning motivation to be seen. Students who repeatedly fail in learning will, in many cases, drop out. In order to address this situation, teachers, schools, and parents use TOLP learning as a source of after-school remedial materials and tools. It is hoped that students' interest and attitude can be improved, and, thereby, their learning performance can be improved as well. Scholars [46] proved in the past that cognitive variables are related to specific professional abilities and expectations. In addition, learning performance and learning effectiveness have an interactive influence. Hence, TOLP is also regarded as a learning system for remedial teaching in universities. The remedial teaching-learning system can be used to enhance students' interest and performance.
The researcher uses TOLP as a pre-class preview method and Kahoot, Quizlet Live, and XMind mobile device apps in the classroom as a mixed teaching method. For the group discussion, the learner uses the app device to increase motivation and memory through game-manner interaction. The literature were reviewed above indicates that TOLP is a potential avenue to design effective remedial GDC classrooms and peer interaction can promote students' learning and development. We sorted it out (1) TOLP, (2) a classroom game of Kahoot and Quizlet Live's group interaction model, and (3) XMind (mind mapping app) to engage students in remedial GDC classrooms and promote intrinsic motivation and self-learning, as well as to measure whether the teaching methods employed for the two classes have a significant impact.

Framing and Hypothesis Model
The influence of the learner in the course of study is often due to many factors. This research takes teaching method as the independent variable (IV) with divides it into two groups to compare "flipped teaching" and "traditional teaching", taking cognitive load as the dependent variable (DV). The students from two different classes will be observed to determine whether differences in teaching methods have a significant effect on cognitive load ( Figure 1). Based on the above research framework, we propose the following four hypotheses: There is no significant difference in mental load between flipped teaching and traditional teaching.

Hypothesis 2 (H2).
There is no significant difference in physical load between flipped teaching and traditional teaching.

Hypothesis 3 (H3).
There is no significant difference in time load between flipped teaching and traditional teaching.

Hypothesis 4 (H4).
There is no significant difference in classroom interaction between flipped teaching and traditional teaching.

Hypothesis 4 (H4):
There is no significant difference in classroom interaction between flipped teaching and traditional teaching.

Research Design and Structure
We used a quasi-experimental design to observe, measure, and record the relationships between variables. Our research adopts the methods of "The Flipped Classroom: instructional efficiency and impact of achievement and cognitive load levels", published by Turan and Goktas in 2016 [47]. Their study concerned a 10-week course in the spring semester of 2013-2014. Participants included experimental groups and a sample size of 116 in the control group. The results showed that, compared with the traditional teaching model, the students in the flipped classroom teaching model had higher academic performance and lower cognitive load, and so, when designed effectively, the flipped classroom method can be considered a useful approach in higher education settings. Therefore, this teaching experiment was conducted during an 18-week GDC course from September 2019 to January 2020 (one semester).
This research used TOLP in experimental group. The teacher recorded a short teaching video before class. Students were allowed to enter the digital platform for learning before class. In the flipped classroom, with six hours of classes per week, we used group interactive games to encourage creative thinking, assigning Kahoot and Quizlet Live on mobile devices. In the process of participating in the discussion, students learned (1) team spirit, (2) peer mutual assistance, (3) independent exploration, and (4) thinking skills. Creative thinking and design keywords after the group's discussion were made into a mind map, and XMind (a mind mapping app) was used on mobile devices. Finally, we continued the design thinking in graphic design and let students participate in the TISDC international student design competition. In order to enhance students' interest and motivation in the course, we allowed students to review the learning materials and learn independently at home through TOLP's mobile devices. Moreover, we used a mixed teaching method and the group interactive game mechanism in the flipped classroom. In the classroom implementation, a variety of learning platforms and apps were used on mobile devices ( Figure 2). However, in the control group, the "traditional teaching"

Research Design and Structure
We used a quasi-experimental design to observe, measure, and record the relationships between variables. Our research adopts the methods of "The Flipped Classroom: instructional efficiency and impact of achievement and cognitive load levels", published by Turan and Goktas in 2016 [47]. Their study concerned a 10-week course in the spring semester of 2013-2014. Participants included experimental groups and a sample size of 116 in the control group. The results showed that, compared with the traditional teaching model, the students in the flipped classroom teaching model had higher academic performance and lower cognitive load, and so, when designed effectively, the flipped classroom method can be considered a useful approach in higher education settings. Therefore, this teaching experiment was conducted during an 18-week GDC course from September 2019 to January 2020 (one semester).
This research used TOLP in experimental group. The teacher recorded a short teaching video before class. Students were allowed to enter the digital platform for learning before class. In the flipped classroom, with six hours of classes per week, we used group interactive games to encourage creative thinking, assigning Kahoot and Quizlet Live on mobile devices. In the process of participating in the discussion, students learned (1) team spirit, (2) peer mutual assistance, (3) independent exploration, and (4) thinking skills. Creative thinking and design keywords after the group's discussion were made into a mind map, and XMind (a mind mapping app) was used on mobile devices. Finally, we continued the design thinking in graphic design and let students participate in the TISDC international student design competition. In order to enhance students' interest and motivation in the course, we allowed students to review the learning materials and learn independently at home through TOLP's mobile devices. Moreover, we used a mixed teaching method and the group interactive game mechanism in the flipped classroom. In the classroom implementation, a variety of learning platforms and apps were used on mobile devices ( Figure 2). However, in the control group, the "traditional teaching" method was used to explain the steps of computer graphic design during classroom time, supplementing the classroom explanations with a PowerPoint (PPT) presentation, and assigning homework exercises for after class.
Sustainability 2021, 13, x FOR PEER REVIEW 9 of 29 method was used to explain the steps of computer graphic design during classroom time, supplementing the classroom explanations with a PowerPoint (PPT) presentation, and assigning homework exercises for after class. The contents of flipped teaching and traditional teaching were designed with two forms: (1) Flipped teaching: accessing text, images, online videos, and diversified visual learning materials before class, with interactive lectures, collaborative design and creation (group), peer-assisted learning, case participation, and solving homework problems in class; will be carried out by means of after-class practice exercises and homework assignments. (2) Traditional teaching: practice exercises and assignments must be completed at home before class; there are oral lectures and writing on a whiteboard or chalkboard; and the teacher uses spoken language and PPT presentations to explain basic knowledge in the classroom, as shown in Table 3.

Research Object and Survey Sample
This experiment took two different classes of the universities (senior undergraduate students) as the experimental objects at the private universities in our country. GDC was The contents of flipped teaching and traditional teaching were designed with two forms: (1) Flipped teaching: accessing text, images, online videos, and diversified visual learning materials before class, with interactive lectures, collaborative design and creation (group), peer-assisted learning, case participation, and solving homework problems in class; will be carried out by means of after-class practice exercises and homework assignments.
(2) Traditional teaching: practice exercises and assignments must be completed at home before class; there are oral lectures and writing on a whiteboard or chalkboard; and the teacher uses spoken language and PPT presentations to explain basic knowledge in the classroom, as shown in Table 3.

Research Object and Survey Sample
This experiment took two different classes of the universities (senior undergraduate students) as the experimental objects at the private universities in our country. GDC was the teaching subject, including 123 students from experimental group and 90 students from control group, with a total of 213 students.

Variable Measurement and Design
In terms of the "face validity" of this research, we used a 21 question questionnaire designed according to an article by Chen from 2010 [36]. He mentioned that the items were divided into mental demand, physical demand, temporal demand, effort, frustration level, and performance; these six perspectives are discussed in Section 2.5. This research adopted Chen's [36] classification of cognitive load, which was originally divided into mental demand, physical demand, and temporal demand. In the past, scholars had proposed various learning methods, emphasizing the importance of classroom interaction (between students and between students and the teacher) [14,16,21,25]. Classroom interaction generally receives positive feedback [10,17]. In this research, therefore, the concept of "classroom interaction" has been added as an aspect of cognitive load. Therefore, we propose the broad category of "cognitive load", which includes four aspects: "mental load", "physical load", "time load", and "classroom interaction". Table 4 presents the variables in the questionnaire to give a better sense of the degree of impact on students' cognitive load.
Three experts were solicited to undertake the "expert validity" testing, and the influence variables of this research were assessed. They gave their professional opinions and suggested amendments, and the questionnaire design was examined. The original questionnaire was designed with a total of 23 influence variables. Experts suggested that the open-ended feedback for question X23 should be deleted. The original question X7 was removed because it does not assess mental load, but performance in terms of "behavioral motivation". The experts instead recommended the use of a "gatekeeper (the role of the teacher)". The questionnaire is based on the 5-point Likert scale, ranging from "strongly disagree" to "strongly agree". Closed questions are used to provide feedback on the cognitive load of learning throughout the semester.

Research Ethics and Limitations
This research adopted quantitative and qualitative research methods, comparing them with focus group interviews to set specific research goals. Quantitative data were measured by anonymous questionnaire recovery for regional private universities. The aim was to understand whether learners encounter obstacles in the learning process that teacher does not see in class, and to decide how to evaluate learning results.
The results are only applicable to regional private university education in this area of Taiwan. Due to the different cultures and customs of other regions, it is necessary to base the strategies on the opinions of students from different backgrounds. It will be necessary to choose reasonable and scientific evaluation methods for the educational design that suit the particular context.

Research Object and Academic Performance: Basic Information
In terms of gender, females accounted for 74% of the class in flipped teaching and males 26%. The class with traditional teaching had the opposite situation in terms of gender, with males and females accounting for 87% and 13%, respectively. However, about 60% of the students in the flipped teaching class came from a relevant design background (i.e., high school learning). In the traditional teaching class, only about 40% of the students had a relevant design background (see Table 5). The average grades for the two classes for the semester were 89.40 score and 80.95 score, respectively. It is clear that student performance after flipped teaching was higher than that of traditional teaching.

Non-Parametric Testing
We used the Chi-squared test to determine the representativeness of the recovered samples. First, we used non-parametric tests to measure the ratio of male to female students. H0 = The gender ratio of students taught by flipped teaching is the same as that for traditional teaching.
The Chi-squared statistic was 0.011a, and the P-value = 0.917, which is greater than 0.05, so the null hypothesis (H0) was accepted.

Test of Homogeneity
We used the test of homogeneity to measure the distribution of two samples for the same variable. In analyzing samples from a private university in the central region of the country and a private university in the south, we hoped to determine whether the two counties and cities had similar distribution patterns and the same characteristics, to avoid external interference. H0 = The sample size of flipped teaching is the same as that of traditional teaching. The Chi-squared statistic was 213.000a, and the P-value = 0.468, which is greater than 0.05, so the null hypothesis (H0) was accepted. H0 = The related department of flipped teaching is the same as that of traditional teaching. The Chi-squared statistic was 2.562a, and the P-value = 0.109, which is greater than 0.05, so the null hypothesis (H0) was accepted.
Based on the above observations, the gender ratio of the sample population is consistent. It is also consistent with the homogeneity in related departments. Therefore, we used the sample size of the two classes as a follow-up measure. In addition, the sample size corresponds to 5 times the smallest variable.

Variables' Mean and Standard Deviation
In terms of the average value of "mental load" for flipped teaching and traditional teaching, it can be seen that for X1 "I can understand the learning content of the course", the average values are 4.56 and 4.37, respectively. This means that, under their current mental load, the students can understand the classroom teaching content. Variable with the lowest average value is: X6 "I have studied hard, but I still can't keep up;" the average values are 2.20 and 2.03, respectively. This indicates that the students are keeping up with the course. The average value for "physical load" can be seen in the flipped teaching: X8 "My eyes are very tired". This variable item is the highest, with an average value of 3.24. The average value for traditional teaching is 2.53, indicating that the degree of eye fatigue is close to the acceptable level. For X13, "I have experienced shortness of breath", the average values for the two teaching methods were low, at 2.04 and 1.87, respectively, which both equate to "disagree" answers.
As for the average values of "time load", different results were seen for the flipped teaching method. The average value for X14, "I think the context of the teacher's explanation is clear", was 4.55. The highest average value for traditional teaching was for X15 "I think the teaching schedule is appropriate", at 4.14. The teaching methods of the two classes were different considering the average value of X16 "I can hand in the homework on time in class", which indicated a large gap with values of 4.46 and 3.54, respectively. Classroom learning materials are previewed before class, which means that students can be more punctual about handing in "homework" during class. In traditional teaching, students who do not use video teaching and Supplementary Materials to preview the work at home in advance are required to hand in "homework" in class on time, and their performance is not as good as with flipped teaching. Finally, the average values of flipped teaching and traditional teaching for the "classroom interaction" section indicated that the teacher will assist students as much as possible with learning. The average values for the two were 4.67 and 4.05, respectively, for question X21, "I think the teacher will assist me as much as possible". The lowest average was for X19, "When participating in class group assignments, I discussed and interacted well with my classmates". The averages were 4.47 and 3.67, respectively, as shown in Table 6.

Factor Analysis: Reliability and Validity
A reliability analysis measures the consistency and stability of the results. In this research, the Cronbach's α value, suggested by Cronbach [48], was adopted. If the Cronbach's α value is less than 0.5, it is unacceptable. Kaiser [49] proposed that the retention items of factor loadings should be at least 0.4. In the research of the Varimax rotation matrix, we can see that the factor loadings of variables X5, X6, and X16 are 0.341, 0.312, and 0.369. Therefore, we removed these three variables and then performed the reliability analysis. After deleting items with factor loadings <0.4, the reliability values were all greater than 0.5, which meets the acceptable criteria level (Table 7). Fornell and Larcker [50] proposed that the square root of the average variance extracted (AVE) of each factor must be greater than the correlation coefficient between the two factors in order to have good validity. It can be seen from Table 8 that the square root of AVE of mental load, physical load, time load, and classroom interaction was 0.710, 0.847, 0.808, and 0.829, respectively. All of these are acceptable levels.

Hypothesis Test
The experiment involved anonymous data on graphic design students from two classes. One of them was an experimental group and the other was considered a control group to compare the differences in flipped teaching. We aimed to determine whether there are significant differences between the flipped teaching and traditional teaching methods in terms of the cognitive load of students. A t-test (independent samples) was used to measure the two groups of classes. The results showed that the P-values of the four factors in the cognitive load <0.05 for flipped teaching and traditional teaching all had significant differences (as shown in Tables 9,11,13,and 15). The following is the series of hypothesis testing.
There is no significant difference in mental load between flipped teaching and traditional teaching (H1; Table 9). Based on the above result, a post hoc analysis method was used to find the detailed analysis of the mental load (Table 10). Note: ** P < 0.01 (highly significant), *** P < 0.001 (extremely significant); statistics data.
A number of studies have suggested that flipped teaching can help students to: (a) think effectively and critically; (b) solve problems; (c) understand more easily; and (d) memorize knowledge content, thereby achieving a good learning performance [51]. Among the variables comprising "mental load", only X1, "I can understand the learning content of the course", did not reach significance (P = 0.055); the other variables reached significant difference, indicating that, with both flipped teaching and traditional teaching, students can understand the learning content of the course. X2, "I can remember the professional skills of unit learning after being taught by the teacher", had an average value of 4.45 for flipped teaching and an average of 4.0 for traditional teaching, which means that students are learning actively and independently. Experiments have proven that flipped teaching can promote the active and autonomous learning of students and enhance their achievements (Table 10).
There is no significant difference in physical load between flipped teaching and traditional teaching (H2; Table 11). Based on the above result, a post hoc analysis method was used to find the detailed analysis of the physical load (Table 12). Note: * P < 0.05 (significant), ** P < 0.01 (highly significant), *** P < 0.001 (extremely significant); statistics data.
Meaningful teaching and learning require a lot of cognitive processing. In information processing and teaching design, unnecessary cognitive loads should be avoided. The only variables of "physical load" whose P-values have no significant difference are X12 and X13, "I have a severe headache" and "I have experienced shortness of breath". The average values of X12 are 2.34 and 2.06. The average values of X13 are 2.04 and 1.87, indicating that the students do not have these physical symptoms. However, students had significant P-values for "My whole body is very tired", "My eyes are very tired", and "I have sore shoulders and neck/back and waist/hands and wrist". These two different teaching methods led to significant differences in these variables (Table 12).
There is no significant difference in time load between flipped teaching and traditional teaching (H3; Table 13). Based on the above result, a post hoc analysis method was used to find the detailed analysis of the time load (Table 14). In the past, a lot of research has proposed the benefits of online learning. The main purpose is to solve the problem of student absence so that students who do not attend class can review the key points at home. However, it was unexpectedly discovered that the same was true for students who were not absent [10]. In flipped teaching, the teacher records short instructional videos before class, which allows students to preview the lecture content before the class, and then solve related problems in the classroom. The results show that the P-values all have significant differences. The students who were taught in this way agreed with the statements "I think the context of the teacher's explanation is clear", "I think the teaching schedule is appropriate", and "I think the degree of difficulty of the homework is appropriate". These values were higher than for traditional teaching. The new teaching methods improve the motivation of students to learn independently and make better use of resources and time (Table 14).
There is no significant difference in classroom interaction between flipped teaching and traditional teaching (H4; Table 15). Based on the above result, a post hoc analysis method was used to find the detailed analysis of the classroom interaction (Table 16).
In recent years, scientific and technological information has become essential to people's daily lives. Educators have also begun to perceive that traditional teaching methods and content (a teacher giving classroom lectures) cannot ensure that learners fully concentrate during classroom time, which may affect their learning interest and achievement. At present, many colleges and universities are using online learning platforms. The teacher uploads digital videos and teaching materials to provide learners with pre-class learning. Flipped teaching not only involves pre-class teaching videos but also allows learners to participate in classroom interactions during lectures. In the classroom, learners can discuss and solve problems with their classmates. Note: *** P < 0.001 (extremely significant); statistics data. Some scholars [5,21,25,[51][52][53] have proposed that flipped teaching is different from traditional teaching in that the traditional lectures are emphasized by "lecture teaching" first, with practice and problem solving as the teaching strategies after class. Flipped teaching focuses on collective interaction and solving problems in the classroom. It involves video lectures, quizzes, and exercises that are used as the course model before class. Results of the experiments show that the P-values of variables X18 to X21 indicated significant differences (0.000 ***). This means that the learners have implemented classroom interaction and pre-class videos and materials. The average value of flipped teaching is higher than that of traditional teaching (Table 16). Based on the above quantitative data analysis and results, Table 17 indicates that we should reject the hypotheses.

H1:
There is no significant difference in mental load between flipped teaching and traditional teaching. Reject hypothesis

H2:
There is no significant difference in physical load between flipped teaching and traditional teaching. Reject hypothesis

H3:
There is no significant difference in time load between flipped teaching and traditional teaching. Reject hypothesis

H4:
There is no significant difference in classroom interaction between flipped teaching and traditional teaching. Reject hypothesis

Transcripts of Focus Group Interviews
This research used focus group interviews to assess the flipped teaching, and axial coding was performed. We aimed to understand the learners' feelings and experiences in relation to the use of innovative mixed materials. We compile the interview transcripts below (at the GDC classroom of by Yi-Chieh Chen teacher): Flipped teaching method (AC01) Question: How do you think the learning method of flipped teaching is different from your past experience (AC01)?
• Student (A-05): In the past, after the teacher entered the classroom, the teacher opened the textbook or handout, explained the contents according to the book, and then ended the class. But in the flipped teaching method, the teacher gave us mobile phones to use in class. Then after opening the mobile phone to download the app, the teacher allowed us to play some games and engage in creative thinking. I think it is very fun. • Student (D-03): The teacher is really cool. We all know that Yi-Chieh teacher often takes students to participate in design competitions and win prizes. Previous students obtained a prize of 100,000 NT dollars in the TISDC International Student Design Competition. This was the Brno Biennale Association Special Award and was on the news-so amazing. The teacher is very flexible and lively in class, and also encourages students to assist and discuss with each other, to arouse interest and motivation in learning. I really want to win the prize, and I am envious. • Student (F-02): I think TOLP is really easy to use. I'm not familiar with my classmates.
Sometimes I can use the function of contacting my teacher and classmates on TOLP. You can also ask questions in the discussion board. If the teacher sees it, she will reply to me. I find it very convenient and practical.
Online learning with TOLP (AC02) Question: What do you think of the online learning (TOLP) for pre-class tutoring and after-class remedial of ideas (AC02)?
• Learning by classroom interaction (AC03) Question: Do you think the current method of classroom interaction is different for your relationships with classmates (AC03)?
• Student (G-04): I really like using Kahoot and Quizlet Live. The teacher uses these two apps to arrange games in groups for us. During the game, classmates will also help you. Sometimes the examination will use app software to give us tests, which is very exciting and I like it very much. • Student (C-05): The teacher uses the XMind app to draw a mind map for let us during class. This app is very easy to use, and the mind map can be made easily with connecting lines. During the class, we discussed with our classmates, played games, and thought about creativity. In this process, the teacher will check everyone's progress and status. If you don't understand, you can ask questions right away; it's great. • Student (M-03): A lot of the homework the teacher will solve and discuss in class. For example, the teacher allows time for us to make sketches, and write down the keywords and images in our minds through the process of creative thinking and brainstorming. Then, you can think about your own artwork, or you can discuss it with your classmates. I think it's better than trying to do it on my own at home.

Mental and physical load (AC04)
Question: Do you think that, now that the teacher is using flipped teaching methods, there will be an additional physical or mental load to cope with (AC04)?
• Student (E-02): Originally, there was a lot of homework for students in the Visual Communication Department, but now the homework will be reserved for us to do in class a lot of the time. Based on the content of the above focus group interviews, we can see that some students may be late or absent, but after using online videos and teaching materials, they can catch up to get good learning results. The benefit of flipped teaching is that one can control one's own learning time. The learner can review the material before and after class according to his or her own time arrangements. With the development of the course content from simple to complex, it is essential to appreciate the importance of integrated course design. The TISDC international student design competition also enhances students' interest and motivation.
To summarize the above interviews, due to the advent of smart phones, students are happy to use their mobile phones to gain knowledge during class. A mobile device is used as a test tool for using an app and to strengthen students' interest in learning. TOLP online learning is regarded as a bridge between teacher and students. At the same time, app software such as Kahoot, Quizlet Live, and XMind leads to discussion and interaction between classmates and the peer relationship is strengthened. It also helps students to solve homework problems they cannot solve alone at home.
As for the mental and physical loads, the teacher has set aside a lot of classroom time for solving problems. Even if students have some physical troubles caused by a long drawing time, these can generally be solved through appropriate exercise and rest. Learning is not only to gain knowledge but also to help them know how to practice and make up for any lost learning adaptability.

Assisting Students with Solving Practical Problems
Among the popular flipped classroom methods, experimental evidence from most researchers has shown that active autonomous learning can effectively improve learning performance [54]. When conducting courses in the form of flipped classrooms, instructional videos can help learners to acquire knowledge and skills. On the other hand, learning interaction skills from instructional videos enhance the construction and potential of knowledge through interpersonal interaction [51]. The "Review on teaching and learning of computational thinking through programming: What is next for K-12?" adopts a flipped teaching model of sustainable teaching. First, programming courses involve multiple skills and learning processes, which leads to the need for teachers to carefully design the curriculum [55,56].
In flipped teaching, the teaching method allows all students to employ integrated thinking, and students have a greater flow experience. Students were able to use their mobile phones in class and felt quite happy. In addition to allowing students to acquire knowledge; the teacher also hopes that they can learn happily. In the focus group interviews, students stated that they are happy to use smartphones and applications in the classroom. Students regard modules where teacher uses smartphones as an interesting exercise in creative thinking. Through the method of game design, students are interested in learning.

How Effective Is Online Learning for Flipped Teaching?
The methodology of the flipped classroom is a possible alternative for pedagogic renovation. Online learning with TOLP has the classroom function of a discussion area: students can also ask questions online, and the teacher or classmates can reply. Students think TOLP are really easy to use. They can contact their teacher and classmates, and find it very convenient to use. Flipped classrooms are a good way to learn actively. Students have addressed smartphones as a crucial tool for learning [57][58][59]. From the many relevant studies [52,[57][58][59], it can be seen that flipped learning has taken a step forward into a new age, using innovative strategies and technologies to facilitate flipped learning results. This research demonstrates that students gave the following feedback: Before every class, I read what the teacher is going to teach that day. The teacher will record a GDC video in advance and put it in TOLP. This is very convenient: you know in advance what the teacher wants to teach, and you can learn it quickly.
In addition, we wanted to determine how online learning aids pre-class tutoring and after-class remedial work. In the interview, students did feel apprehensive when they first came into contact with unfamiliar software. However, after getting used to the online learning environment, they found it convenient. At the same time, they found that they could manage their own time and make their learning more autonomous.
Hmm . . . I think I often can't keep up with the class, and sometimes I am accidentally late, I will check it again when I get home. So, I should be able to keep up with the coursework.
(AC02, B-07) At first, I found it a little troublesome, but after I became familiar with the software applications, I found them very convenient.
(AC02, J-06) Students' desire to learn actively and autonomously in the classroom has become a challenge that educators need to face [26]. At present, many colleges have online learning platforms. The digital videos and teaching materials uploaded by teacher cans provide students with activities to complete at their own pace. Through the digital platform, teacher and students can communicate and connect. We found that flipped teaching and traditional teaching both have a significant P-value for time load. This means that, although flipped teaching requires additional time to learn the content of the course, it allows students to be in control of the learning progress much more than traditional teaching does. The average value of the time load for flipped teaching is 4.52, higher than traditional teaching at 4.07. Consequently, students can keep up with the course through online learning.

Mixed Modes for Group Interaction in AI Education
Computer education, AI education, the Internet of Things, big data, and technological wisdom have changed the learning habits of students [60]. Mobile devices are regarded as important the learning tools in group interactive games. Peers use smartphones to download apps and use Kahoot and Quizlet Live to have real-time discussions, and exchange ideas and creative thinking in group interactions. The teacher uses these two apps to arrange games in groups for students. During the game, classmates will also help each other, and it can achieve the effect of mutual assistance. Sometimes the examination will use app software to give students tests, which is very exciting and students like it very much.
In addition, TOLP online learning is regarded as a bridge between teacher and students. Flipped teaching uses the time at school instead of assigning homework. In this way, the help of peers and the ability to learn from each other are strengthened and can increase interest and motivation to learn. The teacher uses the XMind app to draw a mind map for students during class. During the class, students discussed with their classmates, played games, and thought about creativity. So that students would not be idle while studying independently.
At the same time, the teacher set aside a lot of classroom time for solving problems. The teacher believes that, in the process of teaching and learning, independent thinking and discussion among students are very important. In terms of classroom interaction, the average value for flipped teaching is 4.53, which is higher than the 3.82 of traditional teaching, so there were significant differences and we rejected the hypothesis. This also means that, in a flipped classroom, the interaction between students is better than that in traditional lecture settings. In the end, students learn to help each other and something to struggle through alone.

Cognitive Load has Different Effects on Learning
The processes of learning and memorization involve different brain structures and information conversion processes. Effectively employing these is very important for learning. There are many different structures in the human brain involved in learning and memory [61]. The human cognitive framework meets this requirement by combining working memory and long-term memory [62]. Therefore, the excessive load will make the learner unable to absorb the knowledge perfectly. In recent years, many educators have also incorporated cognitive load into their classroom, and made the classroom more interesting with lectures on cooperative learning. A cognitive load test is also useful to understand whether a learner's learning load in the learning process is acceptable.
Learners who are different, in terms of information processing, may also have different outcomes due to the interaction of different elements (e.g., the teaching stage, teaching plan design, teaching strategy, etc.). Among the factors of mental load, the average value of flipped teaching was 4.13, and the average value of traditional teaching was 3.73. Both of the P-values reached a significant level. In sharing the feelings of students, they think there was a lot of homework for students in the Visual Communication Department, but now the homework is reserved for them to do in class a lot of the time. When at home, Students can do exercises to try to loosen up their muscles. The teacher will demonstrate the problemsolving method in class, but other teachers may not be doing this. Furthermore, students are interested in participating in the competition and they will spend time searching for information.
Meaningful learning involves cognitive processing, which may include a connection between graphic and verbal expression [63]. So, in the learning process, do learners also have a physical load to deal with? This is something we must consider. In the transcripts of the interviews, we see some realistic responses. Some students believe that the teacher sets homework problems in the classroom and sets aside a lot of time for students to work on their drawing homework at school. However, some students indicated that students in the design department have a relatively large amount of homework, plus practice techniques, etc., which leads to a long time spent on drawing homework and can lead to some physical strain. Some students also said that, through exercise and rest, these physical problems can be improved. The results showed a significant difference between the practice of flipped teaching and the traditional method at 2.67 versus 2.25. This indicates that flipped teaching does take more time, causing students to suffer more physical strain than during traditional teaching.

Group Communication in Teaching and Learning
In the process of teaching and learning, some learners rely on videos but forget the essence of the classroom lectures. Learners who are new to video teaching may have an automatic rejection reaction that requires them to work from home in advance. Considering course management and the online learning design, the teacher must develop a training program to promote scientific flipped learning, including the use of technology as a teaching and learning support tool, and learning activities employing different strategies for different stages of flipped learning [53].
Based on the above analysis, the group communication behavior system divides the flipped teaching method into three stages: (1) online learning (before class), (2) group interaction (in class), and (3) learning load (after class). Teaching and learning in GDC are developed through the mode of group communication and interaction, and it is a multiparty relationship established between the teacher, students, and classmates. Learning is no longer via the one-way communication that prevails in traditional teaching methods.
Instead, it is two-way or multi-party communication. The teacher uses the time in the classroom to solve many problems, and students develop their skills through independent learning and pursuing their own motivation and interests.
Through such a mode, the mental, physical, and time loads can be addressed at the same time, and the classroom interaction and peer-assisted learning can be enhanced. Teaching and learning are inherently complementary. The flipped classroom can also be regarded as a kind of pre-class tutoring, and at the same time as a mixed teaching mode for after-class remedial. There are many factors influencing cognitive load, in addition to the four factors mentioned in this research. Among them is external interference by teacher in the teaching design, teaching strategy, and teaching stages. Consequently, with different backgrounds and variables, the results may be different (Figure 3).
Teaching and learning are inherently complementary. The flipped classroom can also be regarded as a kind of pre-class tutoring, and at the same time as a mixed teaching mode for after-class remedial. There are many factors influencing cognitive load, in addition to the four factors mentioned in this research. Among them is external interference by teacher in the teaching design, teaching strategy, and teaching stages. Consequently, with different backgrounds and variables, the results may be different (Figure 3).

The teacher allows time for us to make sketches, and write down the keywords and images in our minds through the process of creative thinking and brainstorming. I think it's better than trying to do it on my own at home (AC03, M-03).
Although sometimes I feel sore when I keep painting, I can accept it once I get used to it... Anyway, so long as the homework is complete and handed in on time,  I will not flunk (AC04, H-03). (AC01, D-03   The teacher allows time for us to make sketches, and write down the keywords and images in our minds through the process of creative thinking and brainstorming. I think it's better than trying to do it on my own at home.

The teacher is very flexible and lively in class, and also encourages students to assist and discuss with each other, to arouse interest and motivation in learning
(AC03, M-03) Although sometimes I feel sore when I keep painting, I can accept it once I get used to it... Anyway, so long as the homework is complete and handed in on time, I will not flunk.

(AC04, H-03)
The teacher is very flexible and lively in class, and also encourages students to assist and discuss with each other, to arouse interest and motivation in learning.

Conclusions
According to research survey and interviews, the mixed learning method of multiparty communication is a multi-faceted process. It needs to involve discussion and interaction at home and in the classroom, which is a way to improve learning achievements. The purpose of education is to allow learners to gain something in the process of education. In the generation of smartphones, how to apply innovative technology to teaching systems is a topic that is valued. Educational auxiliary tools provide students with an easier-to-understand operating procedure and communication method. An innovative, mixed learning model requires a spirit of teamwork. However, too many unnecessary learning methods and materials may lead to the poor adaptation of learners.
This research has evaluated whether students involved in a group communication behavior system can represents their opinions on GDC. The results indicated that most learners find that this mixed learning method improves their creative thinking and knowledge, encourages them to participate in group discussions in the classroom, and enhances their learning motivation and interest. At the same time, AI education and smart learning are regarded as sustainable education.