Sandi Ljubic

Mobile Virtual Laboratory: Learning Digital Design

An important part of learning digital design is the acquisition of knowledge through working experience in a laboratory environment, what will corroborate theoretical knowledge exposed elsewhere (e.g. in lectures, through written exercise solving etc.). This paper describes the foundation of a virtual laboratory available to every student at any moment and regardless of her/his whereabouts, following the concepts of universal access. We discuss the main issues in running a digital design lab, the essentials of contemporary mobile technology and the possible solutions to merge the two with the final objective being the development of a multiplatform system able to run both on (desktop) PCs and on mobile devices (terminals). We also discuss issues in the supporting HCI, especially in making the interaction as simple as possible.

Integrating Blink Click interaction into a head tracking system: implementation and usability issues

In the area of human–computer interaction, contemporary head tracking systems are often used as camera-based mouse emulators. While head movement detection provides the basis for related mouse shifting and positioning, standard click actions are usually emulated using stillness counter techniques such as Dwell Click (DC). However, these techniques can be a source of enlarged interaction burden, as users often have to struggle with time-consuming repetitive UI actions. This paper proposes a novel version of Blink Click (BC) action called B2C, based on double eye blink detection, as a valuable supplement for faster mouse click emulation. The integration of the proposed BC action into an existing head tracking system is presented, and implementation issues are thoroughly analyzed. Usability testing of the proposed B2C interaction model, along with the already embedded DC model, has been carried out, providing both quantitative and qualitative outcomes. The results show efficiency improvement as well as a higher level of users’ satisfaction when using the proposed version of BC, thus making it a strong candidate to become a standard feature within the computer-vision-based mouse emulation.

Predicting upper-bound text entry speeds for discrete-tilt-based input on smartphones

Motion sensors integrated into contemporary smartphones allow the introduction of new mobile interaction paradigms, here including tilt-based input control in the mobile context. Namely, as opposed to existing implementations that typically apply continuous feedback on tilting, we define Pitch and Roll movement sequences that change the orientation of the mobile device as discrete-tilt input primitives. The respective commands are then used to manage text entry within three discrete-tilt-based methods thus introduced: keyboard bisection, single cursor, and quad cursor. Each method is based on the use of a particular QWERTY-based keyboard layout with related strategy for character input. We model upper-bound text entry speeds for the input methods, taking into account both movement aspects and language context. The movement model corresponds to both the tilt-based shortest path between two consequent characters, which is theoretically defined, and the time of discrete-tilt execution, which is obtained from user testing experiment we conducted. The linguistic model, comprising digraph statistics, is constructed basing on available English corpora. This modeling approach provides discrete-tilt-based text entry speed predictions representing efficiency rates for expert behavior, i.e. for optimal performance. The results obtained enable the evaluation of the proposed designs without need to test with real users, and can furthermore serve as a baseline for efficiency of text entry implementations that rely on discrete tilt.

Tilt-Based support for multimodal text entry on touchscreen smartphones: using pitch and roll

In this paper we proposea multimodal text entry method for touchscreen smartphones, where standard Tap modality can be used in combination with Pitch and Roll movements that change the orientation of the mobile device. Data from the built-in orientation sensors are used as a basis for commands that support character layout changing. Tilting the device in the appropriate direction will cause visual enlargement of the corresponding half of the current keyboard layout, thus enabling easier character selection, and solely sensor-based text entry. The prototype implementation of the proposed interaction method is analyzed and evaluated via usability testing experiments, with special focus on efficiency of text entry. As the proposed method is also applicable on touchscreen tablets, the form factor of mobile devices is reviewed with respect to text entry performance both of supported interaction modalities (tilt-only and tilt-and-tap) and of possible device orientations (portrait and landscape).

Need for usability and wish for mobility: case study of client end applications for primary healthcare providers in croatia

In the Croatian e-Health system, client end applications for primary healthcare providers must undergo the process of official approval. This process is based on verifying both content and format of messages used in client software for data exchange with the central part of the integral information system. However, there are no formal specifications, nor design guidelines concerning usability and overall user experience. In this paper, we reveal a number of UI usability issues in existing client applications that represent the source of enlarged interaction burden and user displeasure when working with client software. Furthermore, we propose a UI lightweight prototype model, based on both conducted investigation and well known usability guidelines, adding the value of its potentiality for usage in the mobile domain. End users supported our model design, by emphasizing its simplicity and better usability, as well as by showing eagerness for prototype implementation for mobile devices such as smartphones and/or tablets.

On Efficiency of Adaptation Algorithms for Mobile Interfaces Navigation

Many ubiquitous computing systems and applications, including mobile learning ones, can make use of personalization procedures in order to support and improve universal usability. In our previous work, we have created a GUI menu model for mobile device applications, where personalization capabilities are primarily derived from the use of adaptable and adaptive techniques. In this paper we analyze from a theoretical point of view the efficiency of the two adaptation approaches and related algorithms. A task simulation framework has been developed for comparison of static and automatically adapted menus in the mobile application environment. Algorithm functionality is evaluated according to adaptivity effects provided in various menu configurations and within several classes of randomly generated navigation tasks. Simulation results thus obtained support the usage of adaptivity, which provides a valuable improvement in navigation efficiency within menu-based mobile interfaces.

Digital Design Mobile Virtual Laboratory Implementation: A Pragmatic Approach

The omnipresence of m-devices, and especially those of the cellular phones type, certainly makes the basis for the introduction and use of m-learning systems, but their implementation heavily depends on the area to be covered hence showing a different degree of complexity. This especially holds for the area of digital design, where there is the need for handling logic schemes which includes both displaying and modifying them in addition to the usual imaging of text and graphics. In this paper we discuss essential HCI issues, which are related to the implementation of a Mobile Virtual Laboratory for digital logic design. We make use of a pragmatic approach by blending a number of interaction methods known from other application fields hopefully providing a holistic effect in the process of learning and teaching in the mobile.

Finger-Based Pointing Performance on Mobile Touchscreen Devices: Fitts’ Law Fits

In this paper we investigate the utility of Fitts’ law for predicting the performance of finger-based pointing on mobile touchscreens, by taking into account both different screen sizes and appropriate interaction styles. The experimental design bases on randomly generating pointing tasks in order to provide a wider range of both suitable target sizes and required finger movements, thus targeting a better representation of common pointing behavior with respect to the usual static test design with a smaller set of predetermined tasks. Data obtained from the empirical study was evaluated against Fitts’ law, specifically its revision which defines target size as the smaller dimension of a 2D shape. Results show a strong model fit with our data, making the latter a fair predictor of pointing performance on mobile touchscreen devices. Altogether ten finger-based pointing models are derived, revealing Fitts’ law pragmatic utility regarding various mobile devices, interaction styles, as well as real target sizes commonly found in mobile touchscreen interfaces.

Model of a touchscreen interaction benchmark test supporting usability awareness in mobile application development process

In order to create high quality and easy-to-use mobile software, the process of mobile device applications (MDAs) development must be accommodated to usability challenges. As present-day MDAs mostly target smartphones, with touchscreen ones increasingly gaining popularity, the primary focus in improving this process should include support for usability awareness at the earliest possible development phase for this class of mobile devices. In this paper we propose a model interaction benchmark test providing both quantitative and qualitative usability feedback at the elementary touchscreen action level.

Improving Students’ Technical Skills Using Mobile Virtual Laboratory: Pilot Study of Assembly Language Input Methods for Touchscreen Devices

The process of improving technical skills requires students to spend many hours both observing real systems at work and working in laboratories equipped with specially prepared apparatus. Beside personal motivation and discipline, there are objective factors which limit the amount of available laboratory time for students. To deal with the afore mentioned problem for electrical engineering and computer science courses teaching basic concepts of computer architecture at the undergraduate level, we have devised a pocket-size prototyping system which can be controlled from any kind of computer device, here including contemporary mobile phones and tablets. The issue which we tackle in this paper is the efficient use of touchscreen devices to input assembly language code controlling the operation of the main processing unit on the prototyping system. The results of the pilot study performed, which addresses accuracy and time needed to accomplish the task, are rather encouraging, and shows that our special variant of virtual keyboard did not deteriorate students’ performance when inputting assembly code.