Beom Suk Jin

A Study of Pointing Performance of Elderly Users on Smartphones

The number of global smartphone users is rapidly increasing. However, the proportion of elderly persons using smartphones is lower than that of other age groups because they feel it is difficult to use touch screens. There have only been a few studies about usability and elderly smartphone users or designs for them. Based on this background, we studied the pointing action of elderly users, which is a basic skill required to use touch screens on smartphones. We reviewed previous works to determine specific research methods and categorized them into three groups: (a) effect of target size and spacing on touch screen pointing performance, (b) effect of age on pointing performance, and (c) feedback of touch screens. To investigate the touch screen pointing performance of elderly, we conducted two experiments. In the first experiment, 3 target sizes (5 mm, 8 mm, and 12 mm) and 2 target spacings (1 mm, 3 mm) were evaluated. Adding to that, we analyzed whether touch screen pointing performance is dependent on the location of the target. In the second experiment, 3 types of feedback (auditory, tactile, and audiotactile) were evaluated. The results show that (a) pointing performance of elderly was significantly influenced by size, spacing, and location of target, and (b) the performance was higher in audiotactile feedback condition. We expected that these results can contribute to the design of smartphone applications for elderly users.

Usability risk level evaluation for physical user interface of mobile phone

The mobile phone has become an indispensable device in everyday life. However, many usability problems were generated by the multi-functionality of mobile phones. There was an important increase on the user interface (UI) design and usability. With the introduction of a variety of forms and keypads in mobile phones, the users need of controllability, grip-stability, and usability were raised in the UI aspect. Therefore, in this study, we investigated the physical user interface (PUI) elements of mobile phones, and defined the degree of usability risk such as key level value, function level value, and grip level value. Also, this study proposed an evaluation framework to quantitatively measure the usability risk in the mobile phone PUI elements. For this, the mobile phone PUI elements were analyzed and classified by key type, function, and form-factor. Hence, in the case study was investigated and evaluated 133 mobile phones in the market by the proposed framework. As a result, the proposed evaluation framework enabled the measurement of the mobile phone usability risk level in the early stages of the concept design. This made possible the prediction of design problems related with the mobile phone PUI.

Development of the Conceptual Prototype for Haptic Interface on the Telematics System

Driver safety and workload have become a crucial issue as the telematics system has evolved in a complex manner. To solve this problem, the aim of this study is to develop a conceptual prototype that supports haptic interface, an eye-free technology, with free navigation based on the users mental model. The conceptual prototype for haptic interface is established through identifying the problems with previous haptic interface devices and defining functional requirements for the next generation telematics system. In addition, 25 criteria for a haptic device design are identified and applied to evaluate the conceptual prototype. These criteria are classified in a hierarchical order, and an Analytic Hierarchy Process (AHP) evaluation model is constructed accordingly. The AHP evaluation framework reveals critical factors as well as the degree of importance in designing the haptic device. As a result, an evaluation method has been developed for the prototype of the early phase of the haptic device design.

A study for usability risk level in physical user interface of mobile phone

The purpose of this study is to develop a framework of quantitative evaluation of PUI risk level to ensure the usability in designing mobile devices. Three PUI factors--key type, use scene and device form--were selected as the main criteria for PUI risk level. They are defined as Key Manipulation Value (KMV), Function Manipulation Value (FMV) and Handling Value (HV), considering the requirements. In short, this study provides a framework of quantitative evaluation with the requirements of the three PUI factors, and analyzes risk level by KMV, FMV and HV. This result can be utilized as a criterion for usability at the design phase. In addition, evaluation with this framework at the early design phase helps to anticipate the problems, so the opportunity to solve the problem can be offered in advance.

Development of AHP model for telematics haptic interface evaluation

These days, the main focus in developing telematics systems is to promote safety by decreasing the workload of the driver. To achieve this goal, simplification of the interface as well as the resolution of GUI interaction problems must be worked on. For this research, objective and quantitative assessments are provided in the early steps of building the haptic interface model. The purpose of this research is to create an evaluation model that uses the Analytic Hierarchy Process (AHP) method to fulfill user requirements. This research developed an AHP evaluation model that can present recommendations, as well as the degree of importance, for haptic interface design with quantitative assessments of the prototype by finding out the absolute and relative importance for evaluation groups and factors in early design levels using AHP.

Web-Based System Development for Usability Evaluation of Ubiquitous Computing Device

Recently, with the development of electronic technology, information technology (IT) devices that satisfy user requirements, such as PMP (Portable Multimedia Player), PDA (Personal Data Assistant), UMPC (Ultra Mobile Personal Computer) and mobile phones have been developed. These devices are making wireless communication and network communication more accessible, and by the ubiquitous paradigm, provide accessibility of information everywhere. The appearance of these devices and the development of the technology are integrating and converging in the IT devices. Therefore, there are significant changes in the purpose and environment of IT device applications. This is due to the modification of the environment in which the device is used (not only in a passive state but also in a motional state), which has a greater influence on usability. Therefore, a new methodology is required to evaluate the usability of the devices. In previous studies, by gathering and integrating the usability factors and ubiquitous characteristics, the Ubiquitous Evaluation Factor was obtained. For each factor of ubiquitous devices, deconstruction was accomplished for each usability evaluation. Through this process, components of ubiquitous devices could be extracted. Evaluation scores of ubiquitous device components and the score of the evaluation of each usability factor could be obtained from the usability evaluation. This evaluation framework was developed as a Web-based system to let the users perform the usability evaluation without having trouble with the location. This system was developed in Windows Server 2003 Enterprise Edition platform. Web Server IIS (Internet Information Server) 6.0 was used, and MS-SQL 2000 was used for the database server. For development of language, ASP (Active Server Page) was used, which is run in IIS. This study is meaningful in that through a Web-based system, various people could easily access the device, and in that evaluation of a portion of the device as well as the entire device is possible.

A new framework of measuring the business values of software

A new framework for measuring the business values of software is presented. The business values of software are categorized to two groups: tangible- and intangible-benefit. An implicit approach is used to quantitatively measure the intangible benefit of software by introducing two concepts, product attribute and quality attribute. The approach can relate the quantitative value from the usability test into the qualitative, intangible benefits of software. As an example, the proposed framework is applied to a software system in the development stage. We demonstrate the capability of the framework to quantitatively measure the intangible benefits of software as well as the tangible benefit by studying the usability test.