• Journal of Communications and Networks
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• v.17 no.6
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• pp.582-591
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• 2015

A massive distributed storage system is the foundation for big data operations. Access latency performance is a key metric in distributed storage systems since it greatly impacts user experience while existing codes mainly focus on improving performance such as storage overhead and repair cost. By generating parity nodes from parity nodes, in this paper we design new XOR-based erasure codes hierarchical tree structure code (HTSC) and high failure tolerant HTSC (FH HTSC) to reduce access latency in distributed storage systems. By comparing with other popular and representative codes, we show that, under the same repair cost, HTSC and FH HTSC codes can reduce access latency while maintaining favorable performance in other metrics. In particular, under the same repair cost, FH HTSC can achieve lower access latency, higher or equal failure tolerance and lower computation cost compared with the representative codes while enjoying similar storage overhead. Accordingly, FH HTSC is a superior choice for applications requiring low access latency and outstanding failure tolerance capability at the same time.

• Journal of Power Electronics
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• v.10 no.6
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• pp.579-586
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• 2010

This paper presents the organisation and the technical structure of a remote controlled laboratory in the field of high dynamic drives and motion control. It is part of the PEMCWebLab project with the goal of providing students with practical experience on real systems in the field of power electronics and drives. The whole project is based on clear targets and leading ideas. A set of experiments can be remotely performed on a real system to stepwise identify a two axes positioning system and to design different cascaded control loops. Each single experiment is defined by its goals, the content of how to achieve them, and a verification of the results as well as the achieved learning outcomes. After a short description of the PEMCWebLab project, the structure of the remote control is presented together with the hardware applied. One important point is error handling as real machines and power electronics are applied. Finally, a selection of experiments is presented to show the graphical user interface and the sequence of the laboratory.

• The Journal of the Korean dental association
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• v.58 no.11
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• pp.670-682
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• 2020

This research examined the difference in cognitive load and the virtual presence depending on auditory feedback and task difficulty in haptic-based dental simulation. In the field of dental education, practice-centered training using handpiece has been crucial because a practitioner's psychomotor experience has a significant impact on the mastery of treatment skills. For the novice, it is necessary to reduce errors in dental treatment to enhancing skill acquisition in the haptic practice. In the training process, the force-feedback is crucial to elaborate subtle movement to guide what to do and how it should be hard or soft. However, It is not easy to add force-feedback to generate kinetic experience training. As an alternative method, we examined that auditory feedback can help learners' skill training. In this study, we analyzed how the presence/absence of auditory feedback at the different levels of task difficulty impacts learners' psychological demand and virtual presence in the virtual reality simulation. For this study, 29 dental college students participated in a dental simulation. The participants were grouped into two conditions that are with and without auditory feedback. Additionally, two consecutive tooth preparation tasks with different levels of difficulty were used in the simulation. The auditory feedback condition gives alarms to a learner when he treats a non-targeted tooth with a virtual handpiece. The user's cognitive load and virtual presence were measured to examine the effects of auditory feedback. The results revealed that the main effect was found in cognitive loads. Also, a significant interaction effect was shown in the virtual presence. We discussed the effective design methods for the virtual reality-based dental simulation through the result of this study.

• Design Convergence Study
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• v.16 no.4
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• pp.115-126
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• 2017

The intelligent product is a product in which interactive technologies are applied to an existing common product, called a mother product. This study focuses on interaction design of a hedonic intelligent product and investigates an efficient method of input control of hedonic intelligent products. The hedonic intelligent product is a product in which the hedonic attributes such as play and pleasure are added to the mother product. Utilitarian intelligent products enhance practical functions of mother products. The utilitarian intelligent product finds user behavior in the mother product to improve functional elements for a user experience design. On the other hand, hedonic intelligent products find various emotional values that impart hedonistic attributes and apply them to design. The input method studied through the case study is classified into the imitation input method and the transformation input method derived from the mother product. Based on this, two independent variables of intelligent pinwheels were designed, and its usability evaluation was conducted under the same output condition to investigate a more effective input method. As a result, the transformation input method was rated higher in originality than the imitation input method. This result implies that users had new experiences from the transformation input method, which leads to a higher intention of paying for new experiences.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.763-764
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• 2013

A three-dimensional image capturing device and its signal processing algorithm and apparatus are presented. Three dimensional information is one of emerging differentiators that provides consumers with more realistic and immersive experiences in user interface, game, 3D-virtual reality, and 3D display. It has the depth information of a scene together with conventional color image so that full-information of real life that human eyes experience can be captured, recorded and reproduced. 20 Mega-Hertz-switching high speed image shutter device for 3D image capturing and its application to system prototype are presented[1,2]. For 3D image capturing, the system utilizes Time-of-Flight (TOF) principle by means of 20MHz high-speed micro-optical image modulator, so called 'optical resonator'. The high speed image modulation is obtained using the electro-optic operation of the multi-layer stacked structure having diffractive mirrors and optical resonance cavity which maximizes the magnitude of optical modulation[3,4]. The optical resonator is specially designed and fabricated realizing low resistance-capacitance cell structures having small RC-time constant. The optical shutter is positioned in front of a standard high resolution CMOS image sensor and modulates the IR image reflected from the object to capture a depth image (Figure 1). Suggested novel optical resonator enables capturing of a full HD depth image with depth accuracy of mm-scale, which is the largest depth image resolution among the-state-of-the-arts, which have been limited up to VGA. The 3D camera prototype realizes color/depth concurrent sensing optical architecture to capture 14Mp color and full HD depth images, simultaneously (Figure 2,3). The resulting high definition color/depth image and its capturing device have crucial impact on 3D business eco-system in IT industry especially as 3D image sensing means in the fields of 3D camera, gesture recognition, user interface, and 3D display. This paper presents MEMS-based optical resonator design, fabrication, 3D camera system prototype and signal processing algorithms.

• Journal of Korean Library and Information Science Society
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• v.28
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• pp.447-475
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• 1998

We are seeing a shift of the focus of information service from system-centered(data-centered or intermediary-centered) a n.0, pproach to user-centered a n.0, pproach. Sense-making theory is one of the user- centered a n.0, pproaches. This study focused on user-centered information service paradigm concepts of Dervin's sense-making theory and interpreting sense-making theory in the practical context of library services. The sense-making theory is basically a cognitive a n.0, pproach to information-seeking, in that it recognizes information as something that involves internal cognitive processes. The user of information becomes the focus in this sense-making model. The sense-making theory sees information as subjective, situational, and cognitive. It focuses on understanding information within specific contexts and on understanding how information needs develop and how they are satisfied. It regards the user not as a passive receive of external information but as the center in a active, ongoing process of change. It related to the information needs of users. Dervin's method for studying information needs employs the 'situation-gap-use' metaphor. All information needs stem from a discontinuity or 'gap! in one's knowledge. Dervin believes that information needs can be addressed by understanding the process that each individual goes through in experiencing a gap, in trying to resolve it, and in gaining something (especially new knowledge) from the experience. Sense-making is a process; 'sense' is the product of this process. Sense includes 'knowledge'. However, it includes a host of other subjective factors that reflect an individual's interpretations of a situation including intuitions, opinions, hunches, effective responses, evaluations, questions, etc. For several reasons, however, difficulties are encountered if one attempts a more substantial assessment of the theory. First, it has not yet crystallized into a well-defined theory. Secondly, though the theory has aroused general interest, e.g. within LIS, detailed discussion of its strong and weak points is still lacking. A third source of difficulty is that the basic assumptions of the theory have been explicated metaphorically. If sense-making theory is to be really useful, it needs to be interpreted for library settings. But we have found no attempt to construct an information service based on the theory. Because the research tradition is still relatively young, there are many unanswered questions connected, e.g. with the design of information systems. In any case, e.g. intermediary access systems would be more efficient and effective it their planning could be founded on the user-centered a n.0, pproach.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.309-313
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• 2018

Maker Activity based Design-Thinking 5 Step is a better experience for providing the public with a better approach to design by sympathizing with human needs and exploring the public's potential desires. This paper studied the teaching method by applying the value of the Maker Training that emphasizes the importance of sharing and opening results with others after creating them based on the ideas of the learners using different tools, the basic mind of Design-Thinking with the observation and empathy about human beings and the derivation of user-centric results to the SW coding curriculum. For this purpose, we studied teaching methods by Design-thinking based on sections that require coding in the information classes of the secondary school curriculum. We demonstrated the class to a group of education experts by applying the syllabus of instruction. Then we collected evaluations and opinions of the experts and we modified the syllabus to reflect the collected assessment. Under the Design-thinking 5 step foundation, classes were demonstrated with a group of education experts, opinions collected, and suggestions collected were reflected on the assessment outcome. I think that It is an effective training opportunity to practice a widespread idea that enables infinite thinking and a convergence of thinking that brings out the best decision from a widespread idea.

• Journal of Digital Convergence
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• v.14 no.3
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• pp.55-62
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• 2016

Today, demand for job training of married immigrants is increasing. This research aims to propose developmental Edu-Tech based on the demand for education contents and the characteristics of multicultural family. Based on analysis such as FGI(focus group interview) and expert interview, this paper presents a four methods for development of EduTech for multicultural people, such as language skills, the recommendation technology of customized training contents, contents design based on gamification and user experience design. This research contributes to the direction of the method to use EduTech as a tool for gaps in education and welfare state.

• Journal of the Korea Convergence Society
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• v.13 no.4
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• pp.643-651
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• 2022

The mobile augmented reality(MAR) market is rapidly growing with following the sudden rise of the metaverse. However, research on improving user experience in mobile augmented reality environment is lacking. This study aims to develop the usability principles of an AR-based smartphone app. The research conducts following methods. 1)The characteristics of MAR were understood to identify usability elements of AR apps. 2)Usability principles were collected through analysis of case studies on the usability of AR and the 14 usability principles were developed through in-depth interviews with experts for the purpose of chunking. 3)To verify the 14 developed usability principles, evaluation items were composed based on the usability principles and usability evaluation survey was conducted. Consequently, significant differences were found in immersivity, presence, efficiency, satisfaction, playfulness and It was verified that the developed usability principle is useful in developing AR based smartphone apps. This study is meaningful in that it conducted the basic research of mobile AR usability principles

• Science of Emotion and Sensibility
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• v.21 no.1
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• pp.59-70
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• 2018

With the breakthrough of speech recognition technology, conversational agents have become pervasive through smartphones and smart speakers. The recognition accuracy of speech recognition technology has developed to the level of human beings, but it still shows limitations on understanding the underlying meaning or intention of words, or understanding long conversation. Accordingly, the users experience various errors when interacting with the conversational agents, which may negatively affect the user experience. In addition, in the case of smart speakers with a voice as the main interface, the lack of feedback on system and transparency was reported as the main issue when the users using. Therefore, there is a strong need for research on how users can better understand the capability of the conversational agents and mitigate negative emotions in error situations. In this study, we applied social strategies, "forewarning" and "apology", to conversational agent and investigated how these strategies affect users' perceptions of the agent in breakdown situations. For the study, we created a series of demo videos of a user interacting with a conversational agent. After watching the demo videos, the participants were asked to evaluate how they liked and trusted the agent through an online survey. A total of 104 respondents were analyzed and found to be contrary to our expectation based on the literature study. The result showed that forewarning gave a negative impression to the user, especially the reliability of the agent. Also, apology in a breakdown situation did not affect the users' perceptions. In the following in-depth interviews, participants explained that they perceived the smart speaker as a machine rather than a human-like object, and for this reason, the social strategies did not work. These results show that the social strategies should be applied according to the perceptions that user has toward agents.