Youngjae Lim

Usability Evaluation of the Size of Small Touch Keys for the Smart Phone

Summary of ANOVA results * Statistically significant at α = 0.05. 사이즈 대비 가로 50%, 세로 30%임을 감안하여 이와 동일한 비율로 디자인하였다. 실험참여자에게 실험기기를 통해 제시되는 5자리 숫자는 1부터 6사이의 숫자로 구성하였다(5 digit numeric entry task : 63542, 61453, 62142, 63512, 62536, 62632, 65426, 65242, 61253). 숫자조합은 총 9종류로 키 간 이동거리가 모두 동일하도록 설계하였다. 각각의 숫자조합은 36개(사이즈×간격 : 4×9)의 실험 조건 당 각 4회씩 동일하게 제시되도록 하여 한 실험에서 36개의 터치 키 조건과 함께 랜덤(randomize)하게 제시될 수 있도록 구성하였다. 실험조건이 끝날 때 마다 , 수행시간, 에러율은 실험을 위해 개발된 프로그램에 의해 자동으로 기록되도록 하였다. Figure 2 . Experimental prototype 2.4 실험 절차실험은 크게 준비단계, 연습단계, 본 실험 단계, 주관적 만족도 평가단계로 구성되었다. 준비단계에서는 실험자가 실험 참여자에게 실험목적과 실험 task를 설명한 후, 실험에 필요한 기본정보를 수집하였다. 연습단계에서는 실제 객관적 수행도와 주관적 불편도를 측정하기에 앞서 실험참여자가 실험 기기에 익숙해질 수 있도록 연습할 시간을 제공하였다. 본 실험단계 에서는 입력해야 할 5개의 숫자로 이루어진 숫자조합이 실험 기기의 디스플레이 부분에 표시되면 실험참여자가 하단 부분의 터치 키를 이용하여 5자리의 숫자를 입력하고 end 버튼을 누르면 하나의 실험 조건에 대한 객관적 측정이 완료된다. 이러한 과정을 108개(4×9×3 : 사이즈×간격×입력방식)의 실험 조건에 대해 반복 측정된다. 입력방식이 동일한 36개의 조건에 대한 실험이 종료되면 3분 정도의 휴식 후 주관적 불편도 평가와 실험 전반에 대한 인터뷰를 실시하였다. 실험참여자 들은 편안한 자세로 의자에 앉아 최대한 자연스럽게 의 세 가지 입력방식(검지, 엄지, 양손 엄지)을 사용하여, 각각 36개의 조건을 수행하도록 하였다. 또한 검지와 엄지의 입력방식에 대한 실험에 있어 주 사용손의 엄지와 검지로 터치 키를 조작하도록 하였다. 36개의 조건에 대한 실험순서와 마찬가지로 입력방식에 대한 실험순서 또한 랜덤(randomize) 으로 제공하여 순서효과(order effect)를 예방하고자 하였다. 스마트 폰과 눈 사이의 거리는 실험참여자가 작업을 수행 하는데 있어 자연스럽고 편안한 거리를 유지하도록 하였다 . (a) Index (b) Thumb (c) Double handed

Comparative Study on Advanced TV Interface Types in the Smart Media World

The prevalence of the Smart TV revealed the great potential for ubiquitous computing. The Smart TV facilitates various video contents and applications through interactive techniques. In order to enhance usability, these techniques should have an intuitive and dynamic interface. This study aims to investigate the usability of remote controls in regards to different interfaces. To achieve this objective, the usability test was conducted with twenty people who had normal vision. The task scenario for the experiment reflects the GUI structure and usage patterns of a commercial Smart TV. This research selected general and motion controllers for evaluation factors. The user response was then collected by subjective and objective measures for an evaluation. While the general controller had a better performance in utilizing basic search or simple navigation functions, the analysis of eye tracking movement revealed that the motion remote controller reduced visual distraction. Moreover, the motion control was relatively favoured in subjective ratings. These results indicate that the motion interface is suitable for advanced smart media.

Cultural Differences in Display Design for Mobile Web-Browsing Tasks

Todays smart phone users spend a considerable amount of time reading texts on mobile displays. Effective readability factors encourage more users to engage themselves into mobile internet service. An investigation through relevant literature survey uncovers that a lot of mobile internet issues are still remain unanswered. The objective of this research was to investigate the impacts of font height, display size and difference in language on the readability using the smart phone. The objective and subjective measures were used to determine the readability of both Korean and English users. Significant differences were found in the reading time and difficulty for different font heights and display sizes. In the case of Koreans, display size has more influences than font height. However, English users perceived the font height to be highly crucial in reading difficulty due to the difference in language. Guidelines of appropriate font and display sizes for full browsing tasks were discussed under relevant conditions.

Development of a Usability Evaluation Structural Model on Car Driver

This study aims to systematically develop a usability evaluation model using the Structural Equation Model (SEM) from experiment of usability on using vehicle. Vehicle developers have been adding many functions for enhance the user satisfaction. But it will be made the trade-off problem of usability and design elements of vehicle interior from attempt to make best usability satisfaction in a restricted space. To solve the trade-off problem, we set a new solution criterion from usability evaluation model. The usability experiment is based on major activity pool from derived users acts pattern in vehicle for make more accurate usability evaluation model. And this model was built with twenty-nine measurement variables for the evaluation of usability of vehicle user. As a result, the proposed SEM model showed statistical significance as well as a high level of R Square (0.7144). This model shows the relationships of detailed usability and design elements. According to the result, this study introduces the criterion to secure the best satisfaction of usability and design elements.

The Study on Selection of human Model for Controllability Evaluation According to Working Postures

Objective: The purpose of this study was to suggest appropriate human model for ergonomic evaluation considering working postures on 3D space. Background: Traditionally extreme design rules have been widely utilized at the stage of designing products. Body size of 5th percentile and 95th percentile in stature has been generally selected for controllability and clearance evaluation, respectively. However, these rules had limitations in reflecting working posture in ergonomic evaluation. Method: In order to define working posture on 3D space, not only sagittal plane but also lateral plane was considered. Kinematic linkage body model was utilized for representation of working posture. By utilizing the anthropometric data of 2,836 South Korean male populations, the point cloud for end points of linkage models was derived. The individuals who were lacking in certain controllability were selected as human models for the evaluation. Result: In case of standing posture it was found that conventional approach is proper for all controllability evaluations. Contrary to standing posture, tall people had less controllability on control location below shoulder point in sitting posture. Conclusion: From the derived proper range on controllability, ergonomic evaluation rule was suggested according to working posture especially in standing and sitting. Application: The results of the study are expected to aid in selection of appropriate human model for ergonomic evaluation and to improve the usability of products and work space.

A Comparison of the Characteristics between Single and Double Finger Gestures for Web Browsers

Objective: The purpose of this study is to compare the characteristics of single and double finger gestures related on the web browser and to extract the appropriate finger gestures. Background: As electronic equipment emphasizes miniaturization for improving portability various interfaces are being developed as input devices. Electronic devices are made smaller, the gesture recognition technology using the touch-based interface is favored for easy editing. In addition, user focus primarily on the simplicity of intuitive interfaces which propels further research of gesture based interfaces. In particular, the fingers in these intuitive interfaces are simple and fast which are users friendly. Recently, the single and double finger gestures are becoming more popular so more applications for these gestures are being developed. However, systems and software that employ such finger gesture lack consistency in addition to having unclear standard and guideline development. Method: In order to learn the application of these gestures, we performed the sketch map method which happens to be a method for memory elicitation. In addition, we used the MIMA(Meaning in Mediated Action) method to evaluate gesture interface. Results: This study created appropriate gestures for intuitive judgment. We conducted a usability test which consisted of single and double finger gestures. The results showed that double finger gestures had less performance time faster than single finger gestures. Single finger gestures are a wide satisfaction difference between similar type and difference type. That is, single finger gestures can judge intuitively in a similar type but it is difficult to associate functions in difference type. Conclusion: This study was found that double finger gesture was effective to associate functions for web navigations. Especially, this double finger gesture could be effective on associating complex forms such as curve shaped gestures. Application: This study aimed to facilitate the design products which utilized finger and hand gestures.

Driver's experience and behavioral patterns through the observation of commercial vehicle driving

The objective of this paper was to investigate the drivers experience of commercial vehicle driving. This activity analysis was performed to account for anything that a person does in the cabin. The main user activities were classified into three groups; critical, significant and moderate. The user activities were also analyzed with respect to ergonomic approaches such as using an ergonomic checklist and an expert evaluation. The evaluation results showed that there was not enough space among the seat control buttons. In addition, the center console lacked storage facilities compared to the occupied space. The observation of behavioral patterns was conducted to guide an observer though the user environment. A total of 11 commercial vehicle drivers were recruited for this study. The 17 representative behavioral patterns were defined in terms of the frequency and severity of events. By taking advantage of observations, a variety of recommendations could be made from the user-centric perspective.