• The Journal of the Acoustical Society of Korea
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• v.22 no.2
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• pp.135-144
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• 2003

A method for the automatic segmentation of speech signals is described. The method is dedicated to the construction of a large database for a Text-To-Speech (TTS) synthesis system. The main issue of the work involves the refinement of an initial estimation of phone boundaries which are provided by an alignment, based on a Hidden Market Model(HMM). Multi-layer perceptron (MLP) was used as a phone boundary detector. To increase the performance of segmentation, a technique which individually trains an MLP according to phonetic transition is proposed. The optimum partitioning of the entire phonetic transition space is constructed from the standpoint of minimizing the overall deviation from hand labelling positions. With single speaker stimuli, the experimental results showed that more than 95% of all phone boundaries have a boundary deviation from the reference position smaller than 20 ms, and the refinement of the boundaries reduces the root mean square error by about 25%.

• Journal of Digital Convergence
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• v.15 no.8
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• pp.351-357
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• 2017

The purpose of this study is to analyze the relationship between users' expectation and satisfaction through analyzing smart phone voice recognition service and surveying the situational satisfaction of voice recognition service. First, the concept and current status of speech recognition service were investigated through literature research, and the questionnaire survey was carried out through questionnaires based on the second and third principles. As a result, the user is most likely to use the smartphone voice recognition service when making a telephone call. Also, it was found that the service is the most used at home and the service is used most when the hand is not available. Through these results, various methods such as personalization service, condition recognition function, automatic emergency recognition, unlocking by voice could be derived. Based on this research, it is expected that it will be used effectively for improving smartphone voice recognition service and developing wearable device in the future.

• Journal of Fisheries and Marine Sciences Education
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• v.20 no.2
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• pp.209-221
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• 2008

While internet and cellular phones are very attractive to adolescents, they cause a lot of problems because of adolescent's addiction to internet and cellular phones. The purpose of this study is to investigate relations among overuse of internet and cellular phone and academic achievement with middle school students according to their sex and grade. For this purpose, the survey consist of 44-item, self-administered paper-and-pencil questionnaire from 444 two middle schools students located in Busan. Also, their academic achievements were used for statistical data processing. As a result, firstly, middle school students did not tend to be so seriously addicted to the internet and cellular phones. The internet was used more by male students and cellular phones by female students, and the more male and female students used the internet, the higher they tended to use the cellular phones. There was a negative correlation between the tendency of internet use and academic achievement, but there were no significant differences between genders. In terms of the tendency of using cellular phones and academic achievement, there were no correlations among male students, but there was a negative correlation in female counterparts. Secondly, in terms of grade, the 2nd-grade students had a higher tendency to use both of them than the 1st- and 3rd-grade counterparts. The tendency of using the internet and cellular phones, in each grade had significantly static correlation and the higher they tended to use the internet, the lower they had academic achievement the 3rd-grade. On the other hand, the tendency of using cellular phones, only 2nd-grade students had low academic achievement.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.2984-2994
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• 2013

The emergence of smart phones has brought about a revolution in introducing a computer into the palm of a hand, and this revolution has lead to a smart society that offers comfort and joy in life; however, some side effects including a smart phone syndrome have been identified on a wider and more varied scale compared with any other IT devices of the past. This paper deduced side effect types and key issues according to type focusing on risk factors in accordance with the purpose of the use of smart phones, and diagnosed social effects based on them. In addition, based on the diagnosed results, the study proposed solutions to minimize side effects in order to produce social understanding and sympathy concerning the desirable utilization of smart phones. The proposed solutions should be able to cope with visible and potential side effects systematically by helping people to utilize smart phones, which are a platform of creativity, cooperation, communications, and entertainments, in a desirable way.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.917-924
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• 2015

In this study, we study that the video attributes captured by built-in camera in smart-phone can effect on the quality of PPG signal. The conditions of video attributes were composed of the bitrate, the resolution, the flash. As each condition, we measured a change in the red value of the video image and calculated a PPI(Pulse to Pulse Interval) for extracting the pulse wave signal. 20 subjects participated in the experiment and this experiment was carried out 18 tasks. The PPG signal was measured simultaneously for two minutes with the PPG sensor in the middle finger and Smart-phone in the forefinger of the right hand. By proceeding the correlation analysis, we obtained the highest correlation condition(83%, p=0.01), which the resolution was $640{\times}480$, bitrate was 5000kbps, flash was on. As a result, this study will be a useful guide for quality of signals in the pulse signal measurement system using built-in camera in smart-phone.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2349-2354
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• 2014

While the number of smart phone subscribers excessing 30 million people, Korea is leaping into the 'smart powerhouse' from IT powerhouse. The popularizat+ion of smart devices so called 'PC in the hand', brought surely change to people's life style, and also it had led to a revolutionary change to and also to business and government. In several corporations of each countries, a variety of smart devices smart devices such as smart phone, tablet PC and E-books have been developing. Nowadays, the usage of the smart phone is not only the simple function calling. It has become a culture of the terminal type in the hand anywhere at any time, which makes can communicate with the others in anywhere and anytime. However, some of the subscribers who visit the website for PC version with the mobile devices screen, can feel kind of discomfort while surfing the net on a smartphone devices because the install of the existing video and flash files and the screen size for computer is not available for mobile devices. Therefore, in this paper, we studied on effective mobile contents generation program using QR code that is two dimensions bar code under the smart device environment. Also, unlike previous QR code generator that decorate standardized design, we realize an original QR code generation system from user perspective.

• Journal of Digital Convergence
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• v.17 no.9
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• pp.89-95
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• 2019

he purpose of this study is to propose a shared platform service that can deal with used books based on small stores. The volume of used book market has more than doubled since the book price system, and large bookstores are actively participating in the used book market. Used book sharing platform is an advanced form of online used book direct trade and can be easily used by installing applications on the user's mobile phone. The second-hand book sharing platform is not a shared platform that creates a huge profit-making enterprise, but a future-oriented shared platform that can benefit all users of the platform. If the shared platform, which is the core of the fourth industrial revolution, is applied to almost all small stores and utilized as a hub for second-hand book transactions, it will establish itself as a more reasonable market for second-hand book transactions.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.4
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• pp.599-606
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• 2017

In this paper, the automatic control system of the stroller brake was designed and manufactured to reduce the safety accident of the stroller. The ultrasonic sensors are used to determine whether the handle of the driver's hand is touching or not, and the gyro sensor is designed to detect the current tilt of the baby carriage. If the next driver's hand is not recognized and the tilt exceeds a certain angle, the servo motor is activated and the hydraulic brake is operated to prevent the accident on the downhill road. Finally, in this paper, a smart phone-based application was developed to make the remote control of the brake possible.

• Journal of Biomedical Engineering Research
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• v.16 no.2
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• pp.191-200
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• 1995

Although air, water, and noise pollutions have been widely recognized, electromagnetic forces (EMF) hazard has been rarely recognized as a pollution and very little studies has been done in this country. Thus, in this study electromagnetic forces radiated by various home appliances, office machines, and communication equipments were measured and so were several places radiating strong EMF such as subway stations and electric substations. Among the home appliances microwave oven radiates lots of magnetic field and microwaves, and electric mattress does strong magnetic field. In video game room strong magnetic and considerable electric fields were measured. It was observed strong magnetic field inside of electric powered train and very strong magnetic and electric fields on some platforms. Hand-phone and car-phone radiate very hazardous level of microwaves to brain and that they rapidly come into wide use. In this study data base for various electric machines and places radiating strong EMFs were constructed and could be used for future epidemiological studies.

• Journal of the Ergonomics Society of Korea
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• v.26 no.2
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• pp.149-155
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• 2007

Recently, various devices requiring text input such as mobile phone IPTV, PDA and UMPC are emerging. The frequency of text entry for them is also increasing. This study was focused on the evaluation of Korean text entry interface. Various models to evaluate text entry interfaces have been proposed. Most of models were based on human cognitive process for text input. The cognitive process was divided into two components; visual scanning process and finger movement process. The time spent for visual scanning process was modeled as Hick-Hyman law, while the time for finger movement was determined as Fitts' law. There are three questions on the model-based evaluation of text entry interface. Firstly, are human cognitive processes (visual scanning and finger movement) during the entry of text sequentially occurring as the models. Secondly, is it possible to predict real text input time by previous models. Thirdly, does the human cognitive process for text input vary according to users' text entry speed. There was time gap between the real measured text input time and predicted time. The time gap was larger in the case of participants with high speed to enter text. The reason was found out investigating Eye-Hand Coordination during text input process. Differently from an assumption that visual scan on the keyboard is followed by a finger movement, the experienced group performed both visual scanning and finger movement simultaneously. Arrival Lead Time was investigated to measure the extent of time overlapping between two processes. 'Arrival Lead Time' is the interval between the eye fixation on the target button and the button click. In addition to the arrival lead time, it was revealed that the experienced group uses the less number of fixations during text entry than the novice group. This result will contribute to the improvement of evaluation model for text entry interface.