• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.4A
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• pp.239-249
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• 2012

Recently, the virtual view generation method using depth data is employed to support the advanced stereoscopic and auto-stereoscopic displays. Although depth data is invisible to user at 3D video rendering, its accuracy is very important since it determines the quality of generated virtual view image. Many works are related to such depth enhancement exploiting a time-of-flight (TOF) camera. In this paper, we propose a fast 3D scene capturing system using one TOF camera at center and two high-resolution cameras at both sides. Since we need two depth data for both color cameras, we obtain two views' depth data from the center using the 3D warping technique. Holes in warped depth maps are filled by referring to the surrounded background depth values. In order to reduce mismatches of object boundaries between the depth and color images, we used the joint bilateral filter on the warped depth data. Finally, using two color images and depth maps, we generated 10 additional intermediate images. To realize fast capturing system, we implemented the proposed system using multi-threading technique. Experimental results show that the proposed capturing system captured two viewpoints' color and depth videos in real-time and generated 10 additional views at 7 fps.

• The Journal of the Acoustical Society of Korea
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• v.26 no.6
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• pp.250-258
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• 2007

Current speech recognition technology s achieved high performance with the development of hardware devices, however it is insufficient for some applications where high reliability is required, such as voice control of powered wheelchairs for disabled persons. For the system which aims to operate powered wheelchairs safely by voice in real environment, we need to consider that non-voice commands such as user s coughing, breathing, and spark-like mechanical noise should be rejected and the wheelchair system need to recognize the speech commands affected by disability, which contains specific pronunciation speed and frequency. In this paper, we propose non-voice rejection method to perform voice/non-voice classification using both YIN based fundamental frequency(F0) extraction and reliability in preprocessing. We adopted a multi-template dictionary and acoustic modeling based speaker adaptation to cope with the pronunciation variation of inarticulately uttered speech. From the recognition tests conducted with the data collected in real environment, proposed YIN based fundamental extraction showed recall-precision rate of 95.1% better than that of 62% by cepstrum based method. Recognition test by a new system applied with multi-template dictionary and MAP adaptation also showed much higher accuracy of 99.5% than that of 78.6% by baseline system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.3
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• pp.239-246
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• 2013

The IEEE 802.15.4 offers standard about PHY and MAC layer and features low power, low bandwidth, and low speed data communication. Because of this reason, IEEE 802.15.4 is only within a limited range such as sensor detection and home network; nevertheless, the research about transmission multimedia data like voice packet through wireless sensor networks is conducted widely. In this paper, we proposed the group communication system based on the sensor network. TDMA/TDD MAC based on the IEEE 802.15.4 PHY for voice communication on the sensor network is designed by improvement existing peer-to-peer voice communication on the sensor network and hardware is implemented for group communication. To measure the quality of designed system, mean opinion score (MOS) is obtained from the experiment and verified by using sine wave method. As a result of an experiment, we expect that a many cases of application solution can be developed using presented system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.3D
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• pp.283-289
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• 2012

Because railways themselves are not enough to provide door-to-door service, they need to be complemented by a transportation system access the stations and a convenient transfer system to access other railway lines. User friendly service policies include a faster, interconnected, and intermodal transportation system. It becomes more important to use deep subterranean space from an economical standpoint in order to promote railway construction projects. In this research, the authors dealt with construction plan for strengthening capacity of deep subterranean railways. Since deep subterranean railways are situated deeper underground than other railways, they are more difficult to access and transfer to, in addition to psychological pressure. Moreover, deep subterranean railways with high speed add access difficulties as the distance between stations increases. Therefore, the authors discuss not only systemization for uniting deep subterranean railways and other transportation facilities but also reinforcement strategies. The purpose of these strategies is so that deep subterranean railways provide mobility while established railways provide accessibility to overcome this problem.

• Journal of Korea Multimedia Society
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• v.7 no.9
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• pp.1219-1232
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• 2004

Recently, the web sites, such as e-business sites and shopping mall sites, deal with lots of catalog image information and contents. As a result, it is required to support semantic-based image retrieval efficiently on such image data. This paper presents a semantic-based image retrieval system, which adopts XML and Fuzzy technology. To support semantic-based retrieval on product catalog images containing multiple objects, we use a multi-level metadata structure which represents the product information and semantics of image data. To enable semantic-based retrieval on such image data, we design a XML database for storing the proposed metadata and study how to apply fuzzy data. This paper proposes a system, generate the fuzzy data automatically to use the image metadata, that can support semantic-based image retrieval by utilizing the generating fuzzy data. Therefore, it will contribute in improving the retrieval correctness and the user's satisfaction on semantic-based e-catalog image retrieval.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1996.11a
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• pp.205-218
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• 1996

World Wide Web(WWW) has a lot of useful charaters. Easiness of use, multi-media data supporting and interactive communication capability are typical reasons why people want to use WWW. But because WWW is based on Internet, it has some security problems which originate in plain format data transmission on physical transmission line. The unique solution fer this problems is data encryption. Since theoritically proved encryption algorithms ensure data confidentiality, a unauthorized user can not know what is transmitted on network. In this paper, we propose a cryptography system which uses public key system. In detail, our public key based web security mechanism is using PGP module. PGP is a e-mail security system implemented by Phil Zimmermann. The basic idea of our propose is data encryption and integrity checking for all data which is transmitted on Web. To implement these facilities, we. use netscape browser extension technology, plug-in. Through these technology, security mechanisms are added on netscape browser.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.561-563
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• 2015

The majority of current streaming services are particular S/W I a separate setup program supports real-time streaming service a reality, will be stored until the end of the video, save for a video about editing and is not available. In this paper, allows the user to save and apply the multi threaded techniques for video based on a system without a separate plug-ins, or installation of programs HTML5 by taking advantage of Web content authoring, real-time streaming system using a Web browser. This saves the video streaming in real time can be used for editing and, on real-time communications and media sharing and streaming Web service you need and will be utilized in the field.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.1-6
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• 2014

Recently, orthogonal frequency-division multiplexing(OFDM), with clusters of subcarriers allocated to different subscribers(often referred to as OFDMA), has gained much attention for its ability in enabling multiple-access wireless multimedia communications. In such systems, carrier frequency offsets (CFOs) can destroy the orthogonality among subcarriers. And the mismatch in sampling frequencies between transmitter and receiver can lead to serious degradation due to the loss of orthogonality between the subcarriers. As a result, multiuser interference (MUI) along with significant performance degradation can be induced. In this paper, we present a scheme to compensate for the SFOs and CFOs at the base station of an OFDMA system. A novel sampling frequency offset estimation algorithm is proposed, which is based on the repetition of a symbol at the communication start-up. Then, circular convolutions are employed to generate the interference after the discrete Fourier transform processing, which is then removed from the original received signal to increase the signal to interference power ratio(SIR). Simulation result shows that the proposed scheme can improve system performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.8
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• pp.1494-1502
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• 2016

With the increasing availability of medical sensors and Internet of Things(IoT) devices for personal use, considering the interaction with users, it is planned to add intelligent function design to the fashionable jewelry, and develop composite multi-function intelligent jewelry through sensors identification. By means of IoT technology, while possessing communication function of intelligent jewelry, the function of intelligent jewelry can be expanded to the linkage network. In order to rapidly manage the mass data produced by intelligent jewelry sensors based on IoT, an intelligent jewelry system for health management is designed and an ontology model of intelligent jewelry system based on IoT is worked out. After the state of the services through the smart phone application is shown. The application provides a personalized service to the user and to determine the risk to show the guide lines according to the disease.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1C
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• pp.90-95
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• 2002

Though the FTP(File Transfer Protocol) has been used widely and stable, It has the structural weakness that can't support current file transmissions so that we have to wait the completion of previous file transmission when try to transmit another file. If try to transmit multiple files concurrently using this FTP, It has to forking multiple FTP servers and clients in each user's PC and ISP's host machine it would result in the waist of memory, resource of network and the high workload of system. In order to solving previous problem, in this paper I have designed the new model of FTP which based on multi-thread and created NFTP(Next-Generation FTP)protocol so that may reduce the workload of system and support current file transmission effectively. I have implemented NFTP and also applied to real service, as a result It have provided reliable service by reducing the workload of system and saved the waiting time which would happened.