• The Journal of the Acoustical Society of Korea
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• v.21 no.6
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• pp.566-575
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• 2002

Low-titrate audio coding enables a number of Internet and mobile multimedia streaming service more efficiently. For the help of next-generation mobile telephone technologies and digital audio/video compression algorithm, we can enjoy the real-time multimedia contents on our mobile devices (cellular phone, PDA notebook, etc). But the limited available bandwidth of mobile communication network prohibits transmitting high-qualify AV contents. In addition, most bandwidth is assigned to transmit video contents. In this paper, we design a novel and simple method for reproducing high frequency components. The spectrum of high frequency components, which are lost by down-sampling, are modeled by the energy rate with low frequency band in Bark scale, and these values are multiplexed with conventional coded bitstream. At the decoder side, the high frequency components are reconstructed by duplicating with low frequency band spectrum at a rate of decoded energy rates. As a result of segmental SNR and MOS test, we convinced that our proposed method enhances the subjective sound quality only 10%∼20% additional bits. In addition, this proposed method can apply all kinds of frequency domain audio compression algorithms, such as MPEG-1/2, AAC, AC-3, and etc.

• Journal of the Korea Society of Computer and Information
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• v.16 no.12
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• pp.59-69
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• 2011

Recently, as people's interest in health care has been rising, the health care service awareness and utilization has been increasing. However, the existing healthcare services have problems such as inconvenience of mobility, the low reliability of input for information and low accuracy of information provided as well. in this study, we developed the m-Health application by utilizing smart phone with improvement of these problems. This application provided the total of 5 services such as notification for risk of cardiovascular disease, personalized dietary recommendations targeted to 20s and 30s who do not properly manage their health care by bad habits. In addition, the benefits and problems of these services were found out through the analysis for the general importance and satisfaction of these services by Importance-Performance Analysis (IPA) technique. In result of IPA analysis, The six items such as 'input accuracy and reliability of information', 'content reliability', 'proper health service recommendations', etc. among 12 of the items needed to receive the effective services on m-Health were belonged to importance and satisfaction area with high level. And, in the 'information security', the importance is high but the satisfaction was low. In conclusion, the further study for strengthening security of information, service update provided with PHR to consistently keep the advantage of these services will be conducted.

• Journal of Digital Convergence
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• v.12 no.12
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• pp.313-321
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• 2014

In current society, the digital era that makes enormous amount of data, and the diversified city, the smart space, which has characteristics of creating, collecting and representing data, is appeared. After 2012, in the social media environment called hyper-connected society with wide-spread smart phone, people started to get interested in public data and big data by generalized mobile device and SNS. At first, development of forming platform of data was focused, but now, many different idea from diverse area have been suggested about data analysis and usage to visualize the space intellectualization service. To focus on the visualization process to increase the usage of this public data for ordinary people more than specialized people, this research grasps the present condition of open data and public data service from the current public data portal and considers the applicability of them. As the result of research, the analysis and application of data to ordinary people decrease the use of paper documents, and this research will help to develop the application which is fast and accurate about individual behavior and demand to utilize public data service in intellectual space.

• 한국HCI학회:학술대회논문집
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• 2008.02b
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• pp.47-52
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• 2008

J.E.N(Joint Enjoyment Network) is the ubiquitous UCC play contents system that provides amusements off-line by utilizing the UCC that people are able to participate in. It is also the entertainment service system that is devised to use contents that could be enjoyed through the cell phone and to make people participate in production, in cases of meeting people off-line during their pastime. The development of this system begins from pointing out the problem of the limitation of the UCC that does participate in production but the produced contents could only be watched, and the UCC only works on-line. The goal of researching this ubiquitous UCC play contents is to suggest the UCC entertainment service system that are available off-line by applying the interactive system to UCC and, by this, to obtain the positive responses about the off-line participating UCC contents. In this research, it chooses scenario and 테스크 performance as the method of deriving the participating UCC from the off-line, and it suggests the ubiquitous UCC play contents system through analyzing the behaviors in each off-line place. Moreover, by developing the prototype that could practically perform the system, it verifies the potentialities of the UCC entertainment service. The anticipation of this study is to make people participate and enjoy not only in production, but also in the contents made. This research will provide the modern people who concern about where to go and what to do with the amusements and will also present a way of new form of contents mixed with UCC and the entertainment service.

• Information Systems Review
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• v.14 no.2
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• pp.1-19
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• 2012

Recently due to the enhancement of education and lifestyle, the trend of healthcare services are changed to a more active and differentiated service in which a continuous self health care is possible. The Smart-Telemedicine system offers medical services by merging Blue-tooth and telecommunication modules to former blood pressure, blood sugar, heartbeat and temperature measuring devices. Moreover, it could analyze one's health pattern which would be helpful for the patient to prevent potential future illness. In addition, the easier accesses to various remote controllable medical check-up programs are offered to public as a number of available smart phone are rapidly escalating. The Smart-Telemedicine system provides the most ideal interactive medical service via accessible smart phones and mobile medical check-up devices at anywhere and anytime. It is very beneficial since it can save patients' time and money because people can reach to the service right at their home and be allowed to take charge of their health care process via longitudinal health data. Therefore, not only social costs that occur in elderly community would be saved, but also business in various forms of medical service field transactions could be possible. This paper will suggest the Smart-Telemedicine System for preventive medicine, its design and analysis of business models and the evaluation of those model.

• Journal of Information Management
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• v.35 no.4
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• pp.1-16
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• 2004

In this paper, we outline the user interface problems that the text messaging users face to provide empirical basis for developing better improved mobile text messaging system. Our initial hypothesis was that the majority of the problems that the text messaging users face, namely, 1) difficulty in correctly understanding the intent of the incoming messages and 2) problem with frequently mis-addressing the recipient of the outgoing messages, can be accounted for by the poor usability of the text messaging user interface. Our analysis is based on the text message-based communication diaries, which were recorded for one week by each and every one of 75 college students, and survey taken from the same subjects. The data was collected in 2004. The students listed various difficulties including the limited message length, obscure input method, lack of mean to express emotional content, lack of receipt confirmation, lack of auto save feature when preparing messages to send, and lack of means to permanently save messages. Some of these problems were also identified in the previous studies. However, we were able to gather additional problems that the users face and also elicit potential solutions to remedy the problems. From these findings and analysis, we attempted to provide ways to improve the text messaging user interface.

• The Journal of the Korea Contents Association
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• v.16 no.8
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• pp.90-96
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• 2016

The 3390 million people, around 83% of the adult population in Korea use smartphone. Although the safety problem of the certificate has been occurred continuously, most of these users use the certificate. These safety issues as a solution to 'The owner of a mobile phone using SMS authentication technology', 'Biometric authentication', etc are being proposed. but, a secure and reliable authentication scheme has not been proposed for replace the certificate yet. and there are many attacks to steal the certificate and private key. For these reasons, security experts recommend to store the certificate and private key on usb flash drive, security tokens, smartphone. but smartphones are easily infected malware, an attacker can steal certificate and private key by malicious code. If an attacker snatchs the certificate, the private key file, and the password for the private key password, he can always act as valid user. In this paper, we proposed a safe way to keep the private key on smartphone using smartphone's unique information and user password. If an attacker knows the user password, the certificate and the private key, he can not know the smart phone's unique information, so it is impossible to use the encrypted private key. Therefore smartphone user use IT service safely.

• Journal of Broadcast Engineering
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• v.22 no.5
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• pp.600-607
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• 2017

Virtual Reality (VR) has lately gained significant attention primarily driven by the recent market availability of consumer devices, such as mobile phone-based Head Mounted Displays (HMDs). Apart from classic gaming use cases, the delivery of $360^{\circ}$ video is considered as another major application and is expected to be ubiquitous in the near future. However, the delivery and decoding of high-resolution $360^{\circ}$ videos in desirable quality is a challenging task due to network limitations and constraints on available end device decoding and processing. In this paper, we focus on aspects of $360^{\circ}$ video streaming and provide an overview and discussion of possible solutions as well as considerations for future VR video streaming applications. This paper mainly focuses on the status of the standardization activities, Omnidirectional MediA Format (OMAF), to support interoperable $360^{\circ}$ video streaming services. More concretely, MPEG's ongoing work for OMA aims at harmonization of VR video platforms and applications. The paper also discusses the integration in MPEG Dynamic Adaptive Streaming over HTTP (MPEG-DASH), which is considered as $360^{\circ}$ video streaming services with OMAF content. In context of the general OMAF service architecture.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.2 s.308
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• pp.48-56
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• 2006

This paper introduces design and implementation of digital photo kiosk system, digital photo printing system, with auto color correction module that considers gamut between touch screen and output device, digital photo printer, to provide user-preferred media. This module performs media correction function to service high quality contents for image captured by digital camera and mobile phone camera. Since it is implemented as LUT for real-time processing, the system offers one-touch interface to user. As a result of implementation, this kiosk system provides user-favorite photo because of black and white mode, sepia mode, and brightness and contrast adjustment. Also it can gives smooth tone transition and photos of similar color to captured image due to auto color correction module.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.6
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• pp.1019-1024
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• 2019

In this paper, we plan to design and manufacture a new sleeping child check system using image and PIR sensors. Therefore, it plans to implement a system that can prevent in-vehicle accidents that can occur due to presence of human and certain temperature inside the vehicle by collecting data from PIR sensors and temperature sensors with the main control device based on Arduino. In addition, the values of sensors can be linked with Bluetooth communication or Wi-Fi communication to send information to the mobile phone, and the sensor values can be printed by texting on the screen. It also plans to use raspberry pie and camera modules to build a display and smartphone streaming service inside the vehicle. Through this, the objective of this study is to prevent safety accidents in school vehicles by making experiments and research in this paper recognize 100% inside the vehicle with the quantitative goal of PIR sensors.