• ETRI Journal
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• v.37 no.6
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• pp.1055-1064
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• 2015

We demonstrate a next-generation high-capacity mobile fronthaul based on radio over fiber (RoF) technology, which links between a digital unit and a radio unit supporting two frequency assignments and $2{\times}2$ multiple input, multiple output antennas. To confirm the technical feasibility of a mobile fronthaul, we experimentally investigate its down- and uplink end-to-end performances including the optical and radio frequency (RF) signal path. Frequency-dependent performance deviations, error vector magnitude variations, overall system performance variations caused by optical to electrical conversion, and intermediate frequency to RF conversions are examined. Experimental verifications on multiple LTE uplink signals are performed for the first time. We also demonstrate several commercial mobile Internet services, YouTube video streaming, and file transfers using off-the-shelf mobile devices, through a mobile fronthaul based on RoF.

• Journal of Navigation and Port Research
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• v.30 no.7
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• pp.611-615
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• 2006

This paper proposes a method for generating radar images used in a ship handling simulator, which includes mathematical logics based on radar equations and information from Openflight format files. In order to make radar image much similar to that of real radar in PPI type, the proposed mathematical logic derives radar video signals under the consideration of not only the data form flight format file of simulation scenes, but also geographical radar's position. The proposed method is considered useful to make radar images in ship handling simulator with accuracy and reality.

• Journal of the Semiconductor & Display Technology
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• v.18 no.3
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• pp.31-35
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• 2019

Human beings have been fascinated by the applicability of the medium of photography since the device was first introduced in the thirteenth century to acquire images by attempting primitive and rudimentary approaches. In the 21st century, it has been developed as a wide range of technology that enables not only the application of artistic expression as a method of replacing the human-hand-painted screen but also the planar recording form in the format of video or image. It is more effective to use the information extracted from the image data rather than to use a randomly given file name in order to provide a variety of services in the offline or online system. When extracting an identifier from a region of an image, high cost cannot be avoided. This paper discusses the image entropy-based approach and proposes a linear methodology to measure the image entropy in an effort to devise a solution to this method.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.61-66
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• 2006

This paper proposes a method for generating radar images used in ship handling simulator, which includes mathematical logics based on radar equations and information from Openflight format files. In order to make radar image much similar to that of real radar in PPI type, the proposed mathematical logic derives radar video signals under the consideration of riot only the data form flight format file of simulation scenes, but also geographical radar's position. The proposed method is considered useful to make radar images in ship handling simulator with accuracy and reality.

• The KIPS Transactions:PartC
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• v.9C no.5
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• pp.637-646
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• 2002

In this paper, an implementation example of Java based MPEG-4 system that follows MPEG-4 standard protocols in order to provide multimedia-messaging service is introduced. The multimedia-messaging service is a wireless LAN based wired and wireless service that delivers multimedia contents including video and audio information. Detailed Methods to develop a MPEG-4 system like technology of MPEG-4 system implementation, definition for wired and wireless multimedia service, DMIF implementation, and mp4 file Parsing are described.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.397-399
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• 2002

최근 무인 감시 시스템 분야에서 리눅스 기반 DVR(Digital Video Recording)시스템의 사용이 늘어나고 있다. DVR시스템은 기존의 아날로그 비디오영상 기록을 대체하여, 카메라에서 입력받은 아날로그 신호를 디지털화(MPEG또는 MJPEG)된 영상을 하드디스크에 저장하는 방법으로 작동하는 주기적으로 빈번한 하드디스크의 쓰기 작업을 수행한다. 또 기록되는 내용의 특성상 높은 신뢰도가 요구된다. 따라서 저장장치의 신뢰도가 중요하며, 만일의 사태에 발생할 수 있는 시스템 고장에도 저장된 정보의 손실을 최소화해야 한다. 저널링 파일시스템은 이러한 요구사항에 적합한 기능을 갖추고 있으며 최근 사용범위가 넓어지고 있다. 본 논문에서는 리눅스 시스템에서 널리 사용되는 4가지 저널링 파일시스템의 상대적인 읽기, 쓰기 및 복구 성능을 비교 평가하고 이를 바탕으로 고 신뢰도의 DVR시스템에 요구되는 적절한 저널링 파일시스템을 제안한다.

• Asia pacific journal of information systems
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• v.33 no.4
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• pp.899-933
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• 2023

The second-generation mobile instant messaging (SMIM) proliferates with various relationship management functions: group chats, audio/video chats, file sharing, real-time location sharing, and nonverbal graphics, such as emojis and stickers. This study integrates the important but often overlooked affordances theory into innovation diffusion and proposes an SMIM continuance intention model. SMIM is a social affordance platform for users to develop new friendships and maintain their relationships. Integrated diffusion of innovation and affordance theoretical frameworks, this study investigates the influence of four factors on the success of using SMIM apps to improve friendship development and relationship management. Data were collected from 231 participants using a survey questionnaire in a public university in Taiwan. The findings confirm the effects of friendship development and relationship maintenance on the intention of users to continue using SMIM apps. Implications for research and practice are discussed.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.560-567
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• 2013

The release of iPhone by Apple in 2009 has changed the life pattern of an individual tremendously. That is, with the emergence of a smart phone, various services including voice/video call, camera, receiving and sending of e-mail, and web browsing have been realized. However, the broader the scope of the use of a smart phone has become, the greater the need for companies to introduce an MDM solution for protecting important documents has become. However the MDM solution may have a problem in that all data such as contacts, pictures, and memos saved in the smart phone can be accessed unlimitedly. For this reason, there is a risk that unwanted violation of privacy may happen to smart phone users. This paper proposed a plan to protect a personal privacy file of smart phone users, which disables access by others except for related smart phone users by enabling a person in charge of security or an MDM manager in a company to have access only to the file which was allowed by smart phone users to be disclosed and by saving non-disclosed files in a virtual disk.

• Proceedings of the KSPS conference
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• 1996.10a
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• pp.362-366
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• 1996

This paper is generally divided in 2 parts. One is the study on vowels about korean singer's lyric song in view of Daniel Jones' Cardinal Vowel. The other is acoustic study on vowels in my singing about korean lyric song. Analysis data are KBS concert video tape and CSL's. NSP file on my singing and Informants are famous singers i.e. 3 sopranos, 1 mezzo, 2 tenors, 1baritone, and me. Analysis aim is to find out Korean 8 vowels([equation omitted]) quality in singing. The methods of descrition are used in closed vowels, half closed vowels, half open vowels, open vowels and rounded vowels, unroundes vowels and formants. The study of the former is while watching the monitor screen to stop the scene that is to be analysixed. The study of the latter is to analysis the spectrogram converted by CSL's. SP file. Analysis results are an follows: Visual and auditory korean vowels quality in singing have the 3 tendency. One is the tendency of more rounded than is usual Korean vowels. Another is the tendency of centralized to center point in Cardinal Vowel and the other is the tendency of diversity in vowel quality. Acoustic analysis is studied by means of 4 formants. Fl and F2 show similiar step in spoken. In Fl there is the same formant values. This seems to vocal organization be perceived the singign situation. The width of F3 is the widest of all, so F3 may be the characteristics in singing. In conclude, the characteristics of vowels in Korean lyric songs are seems to have the tendencies of rounding, centralizing to center point in Cardinal Vowel, diversity in vowel quality and, F3'widest width in compared with usual Korean vowels.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.666-668
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• 2011

Last QoS / QoE technology as part of the HTTP-based adaptive streaming technology has attracted attention. In this paper, HTTP-based adaptive streaming technology Find out about the dynamic. It is based on a dynamic adaptive streaming system over HTTP was designed and implemented. The system converts by the bit rate of MPEG2-TS files, Segment Split, MPD (Media Presentation Description) between servers and clients with the creation of a dynamic and adaptive analysis of network environments over MPD File consists bitrate's player. This diverse network environments, continuous and smooth playback of video will be used in various multimedia fields.