• The KIPS Transactions:PartD
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• v.11D no.3
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• pp.635-648
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• 2004

Extreme programming is the most representative methodology among agile software development methodologies that is agile in business environment which change fast. As software industry is matured, usability of software quality characteristics is emphasized gradually, but effort to obtain usability in extreme programming is insufficient. In this paper, three things lacked in extreme programming are reinforced. First, roles of user interface expert are defined. Second, usability testing method to extreme programming are introduced. Third, development process and products are proposed. The proposed plan is validated by four methods, which analyze supporting software development life cycle, analyze satisfaction of CMM key process areas, analyze satisfaction of CMM practices, and analyze development of green tea shopping mail. Green tea shopping mall is improved 23％ in the estimated running time, 21％ in the learnability. Also, usability is improved 18％ in the heuristic evaluation and 16％ in the questionnaire method.

• Journal of Korea Society of Industrial Information Systems
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• v.28 no.2
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• pp.61-75
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• 2023

This study aims to evaluate the usability of a banking app that is frequently used by the elderly. To this end, the usability PACMAD(People At the Center of Mobile Application Development) model that can be used in mobile was explained and the usability evaluation was empirically verified for the elderly over 60 years of age. For this study, descriptive statistics and variance analysis were conducted using SPSS 25.0 for 165 elderly people who had experience using banking apps. Looking at the analysis results of this study, efficiency, satisfaction, and effectiveness showed relatively high scores, and learnability, memorability, error, and cognitive load showed relatively low scores. In addition, in the verification of differences by age, it was confirmed that there were differences in all variables by age. These results suggest that the elderly's usability evaluation of banking apps and differences by age could be confirmed, but there is also a limitation that comparison with the general public is difficult because the age is limited to the elderly.

• Design Convergence Study
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• v.16 no.5
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• pp.177-190
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• 2017

This research aims to suggest a multimodal non-touch gesture interface design to improve the usability of 3D sculpting task. The task and procedure of design sculpting of users were analyzed across multiple circumstances from the physical sculpting to computer software. The optimal body posture, design process, work environment, gesture-task relationship, the combination of natural hand gesture and arm movement of designers were defined. The preliminary non-touch 3D S/W were also observed and natural gesture interaction, visual metaphor of UI and affordance for behavior guide were also designed. The prototype of gesture based 3D sculpting system were developed for validation of intuitiveness and learnability in comparison to the current S/W. The suggested gestures were proved with higher performance as a result in terms of understandability, memorability and error rate. Result of the research showed that the gesture interface design for productivity system should reflect the natural experience of users in previous work domain and provide appropriate visual - behavioral metaphor.

• Journal of the HCI Society of Korea
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• v.1 no.1
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• pp.21-28
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• 2006

Most of the commercialized wearable text input devices are wrist-worn keyboards that have adopted the minimization method of reducing keys. Generally, a drastic key reduction in order to achieve sufficient wearability increases KSPC(Keystrokes per Character), decreases text entry performance, and requires additional effort to learn a new typing method. We are faced with wearability-usability tradeoff problems in designing a good wearable keyboard. To address this problem, we introduced a new keyboard minimization method of reducing key pitch. From a series of empirical studies, we found the potential of a new method which has a keyboard with a 7mm key pitch, good wearability and social acceptance in terms of physical form factors, and allows users to type 15.0WPM in 3 session trials. However, participants point out that a lack of passive haptic feedback in keying action and visual feedback on users' input deteriorate the text entry performance. We have developed the One-key Keyboard that addresses this problem. The traditional desktop keyboard has one key per character, but the One-key Keyboard has only one key ($70mm{\times}35mm$) on which a 10*5 QWERTY key array is printed. The One-key Keyboard detects the position of the fingertip at the time of the keying event and figures out the character entered. We conducted a text entry performance test comprised of 5 sessions. The participants typed 18.9WPM with a 6.7% error rate over all sessions and achieved up to 24.5WPM. From the experiment's results, the One-key Keyboard was evaluated as a potential text input device for wearable computing, balancing wearability, social acceptance, input speed, and learnability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.3
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• pp.600-611
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• 1996

Recently, neural network-based speech recognition has been studied to utilize the adaptivity and learnability of neural network models. However, conventional neural network models have difficulty in the co-articulation processing and the boundary detection of similar phonmes of the Korean speech. Also, in case of using one phonotopic map, learning speed may dramatically increase and inaccuracies may be caused because homogeneous learning and recognition method should be applied for heterogenous data. Hence, in this paper, a neural net typewriter has been designed using a hierarchical self-organizing classifier(HSOC), and related algorithms are presented. This HSOC, during its learing stage, distributed phoneme data on hierarchically structured multiple phonotopic maps, using Kohonen's self-organizing feature maps(SOFM). Presented and experimented in this paper were the algorithms for deciding the number of maps, map sizes, the selection of phonemes and their placement per map, an approapriate learning and preprocessing method per map. If maps are divided according to a priorlinguistic knowledge, we would have difficulty in acquiring linguistic knowledge and how to alpply it(e.g., processing extended phonemes). Contrarily, our HSOC has an advantage that multiple phonotopic maps suitable for given input data are self-organizable. The resulting three korean phonotopic maps are optimally labelled and have their own optimal preprocessing schemes, and also confirm to the conventional linguistic knowledge.

• Journal of KIISE:Software and Applications
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• v.30 no.1_2
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• pp.117-128
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• 2003

Software usability is a characteristic of the software that is decided based on learnability, effectiveness, and satisfaction when it is evaluated. The usability is a main factor of the software quality. A software has to be continuously improved by taking guidelines that comes from the usability evaluation. Usability factors may vary among the different software products and even for the same factor, the users may have different opinions according to their experience and knowledge. Therefore, a usability evaluation process must be developed with the consideration of many factors like various applications and users. Existing systems such as satisfaction evaluation and performance evaluation only evaluate the result and do not perform cause analysis. And also unified evaluation items and contents do not reflect the characteristics of the products. To address these problems, this paper presents a evaluation model that is based on the mental model of user and the problems, this paper presents a evaluation model that is based on the mental model of user and the emotion of users. This model uses evaluation factors of the user task which are extracted by analyzing usage of the target product. In the mental model approach, the conceptual model of designer and the mental model of the user are compared and the differences are taken as a gap also reported as a part to be improved in the future. In the emotional factor approach, the emotional factors are extracted for the target products and evaluated in terms of the emotional factors. With this proposed method, we can evaluate the software products with customized attributes of the products and deduce the guidelines for the future improvements. We also takes the GUI framework as a sample case and extracts the directions for improvement. As this model analyzes tasks of users and uses evaluation factors for each task, it is capable of not only reflecting the characteristics of the product, but exactly identifying the items that should be modified and improved.