• Journal of Broadcast Engineering
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• v.6 no.3
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• pp.205-214
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• 2001

In this Paper, we present an MP4 file streaming system over IP networks. Using the proposed system a user can access MP4 contents in the servers via H) networks and interact with the contents. The MP4 file format is designed to contain the media information of MPEG-4 and is object-oriented. The presented streaming server system contains GUI, session manager, splitter, SL- packetizer and transmitter. In addition, we knave implemented the client system based on the GUI -2D player, the MPEG-4 reference software. The Presented streaming system is designed use RTF for the media data requiring real-time streaming RTCP for QoS management and TCP for the data such as IOD(Initial Object Descriptor), OD(Object Descriptor) BIFS(Binary Format for Scene), which should be transmitted for the streaming and the data, such as still image and text, which can be entirely transmitted in a packet.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.3
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• pp.13-18
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• 2011

This study deals with the effect of the honing in SCM420H planetary gears. The hardness, tooth profile, lead and roughness of the gear surface can be improved by honing. Therein, the honing techniques are welcomed especially as one of the physical surface improvement methods. As a result, gear honing reduces vibration and noise, and will increase the life of gear. And gear honing also changes the surface of gear tooth in a short time and price, so it is a very important method in manufacturing industry. But nowadays, it is hard to find the detail information of gear honing. The test gear is a planetary gear which is used in the automotive industry. It is manufactured by the hobbing, shaving, carburizing and honing. This study investigates the effect of honing in surface shape of SCM420H planetary gears, including fatigue strength test and characteristics of honing of SCM420H planetary gears.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.2
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• pp.445-452
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• 2010

In this paper, an attempt has been made to design the controller applicable for H.264 level3 encoder of baseline profile on full hardware basis. The designed controller module first stores the images supplied from CMOS Image Sensor(CIS) at main memory, and then reads or stores the image data in macroblock unit according to encoder operation. The timing cycle of the DMA controller required to process a macroblock is 478 cycles. In order to verify the our design, reference-C encoder, which is compatible to JM 9.4, is developed and the designed controller is verified by using the test vector generated from the reference C code. The number of cycle in the designed DMA controller is reduced by 40% compared with the cycle of using Xilinx MIG.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.250.2-250.2
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• 2015

결정질 태양전지의 변환효율은 이미 이론적 한계에 가까워져, 최근 산업에서는 이 대신 제조공정 단가를 낮추려는 연구가 진행되고 있다. 본 연구에서는 태양전지 도핑공정에 대기압 DBD 플라즈마를 응용하여 저렴하게 태양전지를 제작할 수 있는 방법을 모색한다. 대기압 DBD 플라즈마를 발생시키기 위해 DC-AC 인버터 구조의 전원을 사용하여 수십 kHz의 주파수, 수 kV의 전압을 인가하여 $5cm{\times}1cm$ 직사각형 모양의 아노다이징된 알루미늄 전극을 사용하였다. 전극과 Ground 사이에 Argon 가스를 주입하여 플라즈마를 발생시켰으며, 출력전류는 수십 mA의 전류가 측정되었다. $3cm{\times}3cm$의 P-type wafer에 스핀코팅 방식으로 H3PO4를 도포한 후, Wafer 표면에 플라즈마를 조사하여 대기압 DBD 플라즈마를 이용한 태양전지 도핑 가능성을 확인하였다. 플라즈마 출력 전류와 플라즈마 조사시간을 변수로 도핑된 Wafer의 특성을 확인하였다. 도핑 프로파일은 SIMS (Secondary Ion Mass Spectrometry)를 통해 측정하였으며, 전기적인 특성은 4 point probe로 면저항을 측정하였다. 대기압 DBD 플라즈마를 이용해 도핑된 wafer에 전극을 형성하여, 같은 도펀트를 사용하여 Furnace로 열 확산법을 이용해 도핑 공정을 진행한 wafer와 변환효율(Conversion efficiency)을 측정하여, 대기압 플라즈마를 이용한 도핑 가능성을 확인하였다.

• Journal of the military operations research society of Korea
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• v.35 no.3
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• pp.61-79
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• 2009

It is recognized that guaranteeing the interoperability of defense complex systems(SoS: System of Systems, FoS: Family of Systems) provides an information advantage, which is one of the essential factors for determining an warfighting advantage. This study presents the defense KIP(Key Interface Profile) process for improving interoperability of defense complex systems. The KIP process is to develop key interface profiles based on the key interfaces which are identified through the analysis of architecture. The KIP developed can be leveraged to manage the interfaces of complex systems. We verify the effectiveness of the proposed KIP process through a case study based on the systems of counter-fire operation.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.5
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• pp.477-485
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• 2002

In this paper, we present an efficient hardware architecture for the H.263 video codec and its VLSI implementation. This architecture is based on the unified interface by which internal hardware engines and an internal RISC processor are connected one another. The unified interface enables the modular design of internal blocks, efficient hardware/software partitioning, and pipelined paralled operations. The developed VLSI supports the H.263 version 2 profile 3 @ level 10, and moreover, both the control protocol H.245 and the multiplexing protocol H.223. Therefore, it can be used for the complete ITU-T H.324 or 3GPP 3G 324M multimedia processor with the help of an external audio codec. Simultaneous encoding and decoding of QCIF format images at a rate greater than 15 frames per second is achieved at 40 MHz clock frequency.

• Journal of Broadcast Engineering
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• v.18 no.6
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• pp.850-858
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• 2013

In this paper, we propose a method of frame synchronization for stereoscopic 3D video to solve the viewing problem caused by synchronization errors between a left video and a right video using the temporal frame difference image depending on the movement of objects. Firstly, we compute two temporal frame difference images from the left video and the right video which are corrected the vertical parallax between two videos using rectification, and calculate two horizontal projection profiles of two temporal frame difference images. Then, we find a pair of synchronized frames of the two videos by measuring the mean of absolute difference (MAD) of two horizontal projection profiles. Experimental results show that the proposed method can be used for stereoscopic 3D video, and is robust against Gaussian noise and video compression by H.264/AVC.

• Journal of KIISE
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• v.42 no.2
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• pp.162-168
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• 2015

Image data is mostly stored in compressed form because of its huge size. Therefore, a series of cumbersome procedures is required to apply a transformation to image data: decompression, extraction of spatial data, transformation and recompression. In this paper, we employ DCT(Discrete Cosine Transform) coefficients to change the spatial presentation of images. DCT is commonly used in still image compression standards such as JPEG and moving picture compression standards such as MPEG-2, MPEG-4, and H.264. In this paper, we derived mathematically the relationship between the geometry transformation in the spatial domain and coefficient changes in the DCT domain and verified it with images in the JPEG file format. Because of the efficiency of transformation in the frequency domain, our findings can be utilized for light-weight partial image encryption for privacy data protection or entertainment contents protection.

• Journal of the Korean Geotechnical Society
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• v.25 no.1
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• pp.41-54
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• 2009

The purpose of this research is to introduce the new temporary earth retaining wall system using landslide stabilizing piles. This system is a self-supported retaining wall (SSR) without installing supports such as tiebacks, struts and rakers. The SSR is a kind of gravity structures consisting of twin parallel lines of piles driven below excavation level, tied together at head of soldier piles and landslide stabilizing piles by beams. In order to investigate applicability and safety of this system, a series of experimental model tests were carried out and the obtained results are presented and discussed. Furthermore, the measured data from seven different sites on which the SSR was used for excavation were collected and analyzed to investigate the characteristic behavior lateral wall movements associated with urban excavations in Korea. It is observed that lateral wall movements obtained from the experimental model is in good agreement with the general trend observed by in site measurements.

• Journal of Digestive Cancer Research
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• v.8 no.2
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• pp.91-96
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• 2020

The effect of Helicobacter pylori (H. pylori) eradication on the development of metachronous recurrence after endoscopic resection (ER) of gastric adenoma is not well defined. The aim of this study was to assess the efficacy of H. pylori eradication after ER of gastric adenoma for the prevention of metachronous recurrence. A systematic literature review and meta-analysis were conducted using the databases Ovid-MEDLINE, EMBASE, Cochrane Library, KoreaMed, and KMBASE. Thus, a systematic review and meta-analysis was performed to investigate this relationship. Pooled risk ratio for metachronous gastric lesions with regard to H. pylori eradication was calculated, and heterogeneity was also measured. Five eligible studies were finally identified in systematic review, and included in meta-analysis. H. pylori eradication was associated with overall 55% lower odds of metachronous events (RR=0.55; 95 % CI 0.34-0.92). Based on the best available evidence, eradication of H. pylori can also provide protection against metachronous recurrence after ER of gastric adenoma.