## 2 Materials and Methods
### Segmentation of Multimedia Instruction Research Design  
An important aspect of the methodology research design was to include and fulfill five basic steps of the instructional design process: analysis, design, development, implementation, and evaluation. First, the content of the class curriculum was analyzed to point out the main learning outcomes and to identify the influence of the student's prior knowledge level on the learning process. In the design step, different ways of evaluating student learning efficiency were proposed considering the learning objectives. Having in mind different types of information in multimedia learning material and depending on different multimedia presentation principles, the strategy for instructional material design was developed. Based on the previous, implementation was carefully planned to motivate the students to participate in the experiment. The teaching assistants were involved during the phases of learning and testing to provide the necessary support to the research realization. The evaluation was performed by testing the level of the acquired knowledge and the student's quality of experience. The level of acquired knowledge and quality of learning experience depends on two important factors. The first represents the methodology of multimedia content design and the principles of content presentation, and the second represents the influence of working memory and prior knowledge. One of the main goals of this research is to investigate the paired and mutual influence of those two factors on the level of acquired knowledge and quality of experience in distance learning. Therefore, the assessment of multimedia teaching material effectiveness represents the first research topic. In this paper, a general model for the evaluation of the presented multimedia teaching material effectiveness is proposed (Figure 2). The proposed model consists of three sections. Section 1 includes the methodology for multimedia content modeling and the principles of its presentation. Section 2 consists of the two important factors (working memory and prior knowledge influences) that influence learning efficiency. Section 3 represents the learning efficiency assessment based on measuring the level of acquired knowledge and the assessment of the quality of experience of the presented content [31; 32]. As previously described, the segmentation of multimedia materials represents one of the often-used principles in the process of materials modeling. In this paper, the efficiency of the segmentation principle was investigated by considering different methods of multimedia presentation, aiming to reduce the cognitive load and improve learning efficiency and student experience. The impact of questions within the multimedia materials, as a technique to enable segmentation, was also investigated. Considering the principles of multimedia content modeling and presentation methodology, two models were proposed for conducting the experiment and the assessment of the efficiency of learning. Figure 3 presents the efficiency assessment methodology based on segmented linear multimedia (S-LM) usage. In this methodology, when the teaching material is segmented and presented in sequences followed by short pauses and relevant questions (Figure 3), a gradual increase in acquired knowledge is expected. This is related to an even and successive increase in overall prior knowledge. Every time a new multimedia sequence is presented to students, the new knowledge contained within the sequence is added to the student's prior knowledge, impacting the working memory gradually. The gradual increase in the student's knowledge acquisition can reduce cognitive overload. The efficiency assessment methodology of non-segmented linear multimedia (NS-LM) usage is presented in Figure 4.  
When the methodology within the multimedia content was presented without interruptions, pauses, and embedded questions (Figure 4), prior knowledge that affects working memory did not increase gradually.