Interpreting data visualizations is an essential skill in today's education, yet students often struggle with understanding unfamiliar formats. This study investigates how four learning materials - textbook, comic, video, and game - affect middle- and high school students' ability to interpret line charts, area charts, stacked area charts, and stream graphs. We conducted a comparative classroom study with 68 students, using pre- and post-tests, worksheet activities, and group discussions to assess learning outcomes and understanding. Our results show statistically significant improvement in students' understanding of stacked area charts and stream graphs, while no significant differences between the learning materials were found. This suggests that more factors than initially anticipated - such as engagement, motivation and active learning strategies - influence the learning outcome. The analysis of the worksheets revealed that while students could infer surface-level insights from charts, over 70% struggled to identify underlying patterns or relationships. Additionally, a common challenge across all learning materials was reading fatigue, which often led students to skim content, disengage, or misinterpret key information. These findings highlight the need for educational tools and approaches that foster deeper understanding of unfamiliar visualizations, reduce cognitive load, and encourage active engagement.

When watching video in a mobile environment, many distractions can draw the attention of the user away from the terminal, e.g., a smartphone. The power consumed by the phone during video playback is wasted in case the user is not watching. In this paper, we present an interactive video player allowing to temporarily interrupt the playback when the user is looking away, and resume it when the user starts looking at the phone again. In order to detect user inattention, we exploit the front-facing camera embedded in most current smartphones as image source for face detections. We analyze the power consumption of the phone when running our interactive video player in controlled and realistic scenarios, and study the energy savings induced by the attention-aware playback interruption. Additionally, we study the influence of video bitrate and content on power consumption. Finally, we propose a cloud-based approach in which the image captured by the front camera is sent to a server, which performs the face detection. We show that the power savings are significant using this approach, and can compensate the consumption added by the increased wireless traffic.

The major aim of this paper consists of detecting possible masking effects across different media types in a realistic scenario. For this purpose, we presented out-of-sync news clips containing no, one or several additional content elements such as a speaker only or a narrator complemented by a picture, a video, a ticker, background music or noise, to several evaluators. Similar to several previous studies it has been noticed that out-of-sync errors are perceived much earlier when audio presentation precedes video. Furthermore, it has been observed that users prefer simple formats, i.e., a news speaker only, as long as the synchronization errors are low enough not to be noticed consciously. As soon as the time difference between the playback of visual and audible streams starts to be perceivable the viewers can be distracted by using a large number of different content elements. Using one distraction element only is not sufficient to produce a masking effect.

Today, mobile communication devices allow users to access a wide variety of multimedia contents and services. In order to improve user experience and device usability, the design of interfaces and interaction techniques for mobile devices have focused on new modalities, other than those used for desktop computers. In this paper, we describe a novel gesture controlled video player interface for mobile devices. The results of a usability study confirm that users would definitely like to adopt the major part of the proposed features. Furthermore, the responsiveness and reliability of the interface has been studied. Measured response times have been found to be within acceptable boundaries and the number of unrecognised haptic controls is limited.

Video patching is a way for transporting true video-on-demand, that is, instantaneous without any delay, from a video server to several clients. Instead of sending a unique stream to each newly arriving client, clients share as many multicast transmissions as possible, and are serviced only those parts of the video that they have missed. We present a novel video patching scheme using hierarchies of patches. Our scheme minimizes the bandwidth needed by the video server, and may result in the fact that clients receive several streams in parallel. We show analytically that for Poisson arrival our algorithm achieves the optimal possible server bandwidth for all schemes where clients share multicast transmissions. We also show, how our approach can be combined with batching. This combination requires less server bandwidth than all fixed start point periodic broadcast algorithms.