• Journal of Intelligence and Information Systems
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• v.17 no.1
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• pp.53-69
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• 2011

Vision and voice-based technologies are commonly utilized for human-robot interaction. But it is widely recognized that the performance of vision and voice-based interaction systems is deteriorated by a large margin in the real-world situations due to environmental and user variances. Human users need to be very cooperative to get reasonable performance, which significantly limits the usability of the vision and voice-based human-robot interaction technologies. As a result, touch screens are still the major medium of human-robot interaction for the real-world applications. To empower the usability of robots for various services, alternative interaction technologies should be developed to complement the problems of vision and voice-based technologies. In this paper, we propose the use of accelerometer-based gesture interface as one of the alternative technologies, because accelerometers are effective in detecting the movements of human body, while their performance is not limited by environmental contexts such as lighting conditions or camera's field-of-view. Moreover, accelerometers are widely available nowadays in many mobile devices. We tackle the problem of classifying acceleration signal patterns of 26 English alphabets, which is one of the essential repertoires for the realization of education services based on robots. Recognizing 26 English handwriting patterns based on accelerometers is a very difficult task to take over because of its large scale of pattern classes and the complexity of each pattern. The most difficult problem that has been undertaken which is similar to our problem was recognizing acceleration signal patterns of 10 handwritten digits. Most previous studies dealt with pattern sets of 8~10 simple and easily distinguishable gestures that are useful for controlling home appliances, computer applications, robots etc. Good features are essential for the success of pattern recognition. To promote the discriminative power upon complex English alphabet patterns, we extracted 'motion trajectories' out of input acceleration signal and used them as the main feature. Investigative experiments showed that classifiers based on trajectory performed 3%~5% better than those with raw features e.g. acceleration signal itself or statistical figures. To minimize the distortion of trajectories, we applied a simple but effective set of smoothing filters and band-pass filters. It is well known that acceleration patterns for the same gesture is very different among different performers. To tackle the problem, online incremental learning is applied for our system to make it adaptive to the users' distinctive motion properties. Our system is based on instance-based learning (IBL) where each training sample is memorized as a reference pattern. Brute-force incremental learning in IBL continuously accumulates reference patterns, which is a problem because it not only slows down the classification but also downgrades the recall performance. Regarding the latter phenomenon, we observed a tendency that as the number of reference patterns grows, some reference patterns contribute more to the false positive classification. Thus, we devised an algorithm for optimizing the reference pattern set based on the positive and negative contribution of each reference pattern. The algorithm is performed periodically to remove reference patterns that have a very low positive contribution or a high negative contribution. Experiments were performed on 6500 gesture patterns collected from 50 adults of 30~50 years old. Each alphabet was performed 5 times per participant using $Nintendo{(R)}$ $Wii^{TM}$ remote. Acceleration signal was sampled in 100hz on 3 axes. Mean recall rate for all the alphabets was 95.48%. Some alphabets recorded very low recall rate and exhibited very high pairwise confusion rate. Major confusion pairs are D(88%) and P(74%), I(81%) and U(75%), N(88%) and W(100%). Though W was recalled perfectly, it contributed much to the false positive classification of N. By comparison with major previous results from VTT (96% for 8 control gestures), CMU (97% for 10 control gestures) and Samsung Electronics(97% for 10 digits and a control gesture), we could find that the performance of our system is superior regarding the number of pattern classes and the complexity of patterns. Using our gesture interaction system, we conducted 2 case studies of robot-based edutainment services. The services were implemented on various robot platforms and mobile devices including $iPhone^{TM}$. The participating children exhibited improved concentration and active reaction on the service with our gesture interface. To prove the effectiveness of our gesture interface, a test was taken by the children after experiencing an English teaching service. The test result showed that those who played with the gesture interface-based robot content marked 10% better score than those with conventional teaching. We conclude that the accelerometer-based gesture interface is a promising technology for flourishing real-world robot-based services and content by complementing the limits of today's conventional interfaces e.g. touch screen, vision and voice.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.8
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• pp.319-326
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• 2007

To perform fast searching in massive data such as DNA strings, the most efficient method is to construct full-text index data structures of given strings. The widely used full-text index structures are suffix trees and suffix arrays. Since the suffix may uses less space than the suffix tree, the suffix array is proper for DNA strings. Previously developed construction algorithms of suffix arrays are not suitable for DNA strings since those are designed for integer alphabets. We propose a fast algorithm to construct suffix arrays on DNA strings whose alphabet sizes are fixed by 4. We reduce the construction time by improving encoding and merging steps on Kim et al.[1]'s algorithm. Experimental results show that our algorithm constructs suffix arrays on DNA strings 1.3-1.6 times faster than Kim et al.'s algorithm, and also for other algorithms in most cases.

• Journal of the Ergonomics Society of Korea
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• v.31 no.1
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• pp.117-124
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• 2012

Objective: The goal of this study is to design a creative tutoring service, which helps children gain confidence and creativity through learning activities. Background: Nowadays most kids are growing up in a very competitive environment under their parents' zeal for education. A stressful environment can deter a child from the confident undertaking of challenges, leading to depression, anxiety, and feelings of inadequacy. Art therapy helps children work through these issues, however the process led by instructors or parents, and kids still feel anxious studying adults' face to read their thought. Method: To help children address challenges, a creative tutoring service application can provide images with certain tasks instead of asking them to fill in blank areas. The tasks asked by the service system are 1) to visualize children's own experience utilizing visually associated images from given images and 2) to create an illustrated story modifying and re-composing given images. Another task is to learn basic math and words with numbers and alphabets in customized colors. By completing each task children collect awards, which allow them graduate to higher levels of challenges. The outcomes from the tasks are sent to the main server system and reviewed by analysts. Those results are sent to children's parents as a text message on smart phone. Results: Visual implication using images inspires children to make creative stories based on their own experience. Also, children can find their own patterns of reaching answers by using synaesthetic imagery through repetitive practices of creative thinking tasks. Conclusion: Understanding how they feel about doing tasks in certain environments and assessing them in varied situations should be carefully considered when designers approach service design for kids. By focusing on how to tutor children in creative ways, as opposed to focusing on the expected outcome, creative service applications can be designed to reduce children's stress and encourage self expression. Children are predicted to gain confidence through using the service without the concern of comparison by others. Application: The creative tutoring service needs to be developed and tested by varying types of children.

• Journal of the Korean Society of Clothing and Textiles
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• v.37 no.4
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• pp.482-490
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• 2013

This study suggests a suitable logo design application of a three colors LED light source and flexible plastic optical fiber (POF). In this study, characteristic relevant brightness of (according to the embodiment conditions of the flexible POF for logo design) for smart clothing were analyzed through two experiments. The suitable conditions of the logo design for three colors of light source were observed in 'Experiment 1'. The angle of $80^{\circ}$ to $100^{\circ}$ and the length of 8cm to 16cm appeared a more suitable condition for green-colored and red-colored light sources. The angle of $80^{\circ}$ to $100^{\circ}$ at a length of 8cm to 12cm appeared a more suitable condition for a blue-colored light source. In 'Experiment 2', a 'Klavika' in small letter was selected as suitable logo design for the application POF. The alphabet was separated by a morpheme, which is the minimal linguistic unit. All alphabets were classified into sixteen morphemes. The luminance of fourteen morphemes (realized by the embroidery method) were measured and analyzed. Subsequently, eight morphemes appeared to show a relatively equal luminance of $3-4cd/m^2$ in a green-colored light source, $2-3cd/m^2$ in red-colored light source, and $2cd/m^2$ in a blue-colored light source. Four of the fourteen morphemes, showed a 20% brighter level of luminance compared to the eight morphemes above, the cast of combination of green or red light source. This result indicates that a flexible POF with 20% less luminance are believed more suitable for four morphemes combined with a green or red light source. The results of this study provide fundamental data for further approaches to clothing logo design for the application of a flexible POF.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.729-733
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• 2006

Short message service (SMS) is a Popular mobile data service in cellular networks. One SMS message can carry 50 Korean alphabets. Cellular operators standard and develop multimedia message service (MMS) based on P2P as color phones having multimedia solutions such as MIDI, MP3, JPG, PNG, and MPEG have been developed. MMS can be a key cash flow in the non-voice mobile revenue together with SMS. Copyrights protection of contents in a MMS message can be issued as MMS can be the popular P2P service such as MMS. In this paper, we propose MMS DRM system to protect copyrights of contents in MMS with the minimum change of MMS system. The proposed MMS DRM system protect copyrights of contents using DRM Packager, DRM Server, and DRM Agent and support various use cases to activates MMS in mobile networks.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.3
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• pp.143-150
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• 2015

As smart devices get popular, research on gesture recognition using their embedded-accelerometer draw attention. As Dynamic Time Warping(DTW), recently, has been used to perform gesture recognition on data sequence from accelerometer, in this paper we propose Feature-Strengthened Gesture Recognition(FsGr) Model which can improve the recognition success rate when DTW is used. FsGr model defines feature-strengthened parts of data sequences to similar gestures which might produce unsuccessful recognition, and performs additional DTW on them to improve the recognition rate. In training phase, FsGr model identifies sets of similar gestures, and analyze features of gestures per each set. During recognition phase, it makes additional recognition attempt based on the result of feature analysis to improve the recognition success rate, when the result of first recognition attempt belongs to a set of similar gestures. We present the performance result of FsGr model, by experimenting the recognition of lower case alphabets.

• The Journal of the Korea Contents Association
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• v.17 no.7
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• pp.276-282
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• 2017

Password-based authentication is vulnerable because of its low cost and convenience, but it is still widely used. In order to increase the security of the password-based user authentication method, the password is changed frequently, and it is recommended to use a combination of numbers, alphabets and special characters when generating the password. However, it is difficult for users to remember passwords that are difficult to create and it is not easy to change passwords periodically. Therefore, in this paper, we implemented a user authentication system that does not require a password by using the USB memory that is commonly used. Authentication data used for authentication is protected by USB data stored in USB memory using USB device information to improve security. Also, the authentication data is one-time and reusable.Based on this, it is possible to have the same security as the password authentication system and the security level such as certificate or fingerprint recognition.

• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.560-569
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• 2011

In this paper, we propose a text processing method for Hindi characters, Devanagari scripts, in the Android. The key points of the text processing are to device automata, which define the combining rules of alphabets into a set of syllables, and to implement a font rendering engine, which retrieves and displays the glyph images corresponding to specific characters. In general, an automaton depends on the type and the number of characters. For the soft-keyboard, we designed the automata with 14 consonants and 34 vowels based on Unicode. Finally, a combined syllable is converted into a glyph index using the mapping table, used as a handle to load its glyph image. According to the multi-lingual framework of Freetype font engine, Dvanagari scripts can be supported in the system level by appending the implementation of our method to the font engine as the Hindi module. The proposed method is verified through a simple message system.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.43
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• pp.53-74
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• 2009

INCOTERMS have been changed almost every 10 years since ICC established INCOTERMS as trade terms for International transaction. Recently transportation has become bigger, and modernized by means of electronic appliances such as RFID, IT, and containerization. FRC, FOR/FOT, FOA were added in INCOTERMS1980 and every conditions are unified into three alphabets in INCOTERMS1990. The best features of INCOTERMS2000 are that FCA substitute FRC, FOR/FOT, FOA and customs formalities were simplified to make clear for each party of contract. It seems that business circles still stick to old customs of their trade like FOB or CIF not only in Korea but in an international practice even though there have been several revisions of INCOTERMS until now. ICC have tried to provide INCOTERMS3000 to solve problems between a theory and an actual condition of international trade. This study has tried to suggest opinions against INCOTERMS3000 and has surveyed a recognition, an actual using situation and issues of INCOTERMS to get improvements. For a recognition of INCOTERMS has been spread as you can find at tables many kinds of business circles still stick to old customs of their trade terms FOB and CIF. Now there are two alternative plans. Firstly, we need to suggest improvements against inconsistency of INCOTERMS to be applied on newly revised INCOTERMS3000 and educating business circles to use proper conditions of INCOTERMS for their doing business. Secondly, we shall participate in revising INCOTERMS to activate multimodal transport conditions of INCOTERMS and provide solutions to fill gap between a theory and an actual condition of international trade. It seems that terms of multimodal transport such as FCA, CPT, or CIP can be a perfect condition for each party of contract. We have examined the inconsistent features of Ship's rail and notions of on board, and observed how to activate multimodal transport terms. These would be hot issues of next revision of INCOTERMS and we provided improvements on each trade terms, THC charges, or others against INCOTERMS.

• Korean Journal of Cognitive Science
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• v.21 no.2
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• pp.339-357
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• 2010

In this study we examined the context effects in reading Hangul (Korean alphabets) in normal and low vision, using the two different reading techniques, self-paced reading (Experiment 1) and rapid serial visual presentation (Experiment 2). We compared the reading speed of participants with normal or low vision in sentences vs. randomly ordered words. The results from both experiments showed that the reading speed of participants with low vision slowed significantly relative to those with normal vision. However, the patterns in the size of context effects were different in the two experiments. The context effects were larger in low vision than in normal vision in self-paced reading, but they were smaller in low vision than in normal vision in RSVP. This result indicates that context may make a greater contribution for readers with low vision than for readers with normal vision when sufficient time is allowed to read; in contrary, its contribution is smaller for readers with low vision than for readers with normal vision when there is time limitation for reading.