• Journal of KIISE:Computing Practices and Letters
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• v.6 no.3
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• pp.299-310
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• 2000

In this paper, we designed and implemented a personal VOD server using multi-thread for the real-time services of video data to the users. The system consists of service manager, disk manager, and network manager. The service manager controls the user admission to the system using the VBR(Variable Bit Rate) characteristics of MPEG (Moving Picture Experts Group) video data. The disk manager provides the functions for VCR-like operations. The disk manager reads blocks from the disk by the size of GOP(Group of Pictures) and buffers the data to the user's thread. The network manager uses TCP/IP for the communication between the server and the client. The communication starts from the client and the VOD server must respond to this request. The implemented personal VOD system shows an acceptable performance.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.11a
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• pp.111-114
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• 2009

멀티미디어 동영상의 부호화 알고리즘은 기본적으로 손실 부호화(lossy coding)이기 때문에 압축된 동영상에는 불가피하게 화질의 열화가 포함된다. 압축의 정도가 심하지 않거나 압축을 하더라도 영상이 단순하고 움직임이 적은 경우에는 이러한 열화의 영향이 인간의 눈에는 보이지 않지만, 압축률이 너무 높거나 원본 영상에 포함된 움직임이 복잡하거나 공간적으로 세밀한 영역이 많은 경우에는 손실이 심하여 시각적으로 거슬리는 다양한 잡음이 발생한다. 화면 떨림(flickering)은 시간 영역에서의 대표적인 부호화 잡음으로서 프레임율(frame rate)이 너무 낮은 경우에 움직임이 자연스럽지 않고 불연속적으로 튀거나 부호화 비트율(bit rate)을 제어하기 위해서 양자화 파라미터를 변동하는 과정에서 연속되는 프레임들의 화질에 차이를 보이면서 나타나는 현상이다. 본 논문에서는 DMB 환경에서 사용되는 주기적으로 I 프레임이 삽입되는 GOP(Group of Picture) 구조에서 화면 떨림 현상의 원인을 파악하고 멀티미디어 동영상의 시공간적 특성에 따라 특징적으로 나타나는 화면 떨림 현상을 분석한다. 실험 영상으로서 시공간적으로 다양한 특성을 보이며 H.264/AVC방식으로 부호화된 10개의 동영상을 선택하였으며, 양자화 파라미터를 낮은 화질의 영상에서부터 높은 화질의 영상까지 변화시키면서 화면 떨림 현상의 존재 여부 및 정도를 살펴보았다. 실험의 결과로 화면 떨림 현상은 영상의 화질이 너무 좋거나 너무 나쁘지 않은 중간 영역에서 중요하게 고려해야 할 부호화 잡음이며, 프레임 내의 세밀함의 정도, 움직임의 정도, 객체의 크기, 카메라의 움직임 등에 영향을 받음을 알 수 있다.

• Journal of Korea Multimedia Society
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• v.18 no.10
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• pp.1205-1215
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• 2015

Efficient multi-view coding techniques are needed to reduce the complexity of multi-view video which increases in proportion to the number of cameras. To reduce the complexity and maintain image quality and bit-rates, an motion estimation method and temporal prediction structure are proposed in this paper. The proposed motion estimation method exploits the characteristic of motion vector distribution and the motion direction and motion size of the block to place search points and decide the search patten adaptively. And the proposed prediction structure divides every GOP to decide the maximum index of hierarchical B layer and the number of pictures of each B layer. Experiment results show that the complexity reduction of the proposed temporal prediction structure and motion estimation method over hierarchical B pictures prediction structure and TZ search method which are used in JMVC(Joint Multi-view Video Coding) reference model can be up to 45∼70% while maintaining similar video quality and bit rates.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.2
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• pp.283-295
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• 2010

Although some large units, upper than division, have a identification system, most of them depend on US military. Especially, the company unit can not but execute GOP(General OutPost) guidance and battles inefficiently because they apply the method of conventional identification system. urrently, North Korea causes the high tension of peninsular by experimenting nuclear weapons and launching ICBM(Intercontinental Ballistic Missile). In addition, ROK military will reduce the number of personnel and division through reorganizing the structure into NCW (Network Centric Warfare) until 2020. These unstable situation and future tendency require the high technical identification system based on USN(Ubiquitous Sensor Network) in company unit level. his study suggests the method that the company unit apply the identification system based on USN which distinguish between friend and foe in the warfare. The identification system concludes the results through experiment of military analysis model (AWAM; Army Weapon effectiveness Analysis Model). After analyzing the experiment results, it indicates the budget requirement and operational operability of identification system. This will be able to improves battle efficiency and to prevent damages of friendly forces.

• Journal of Korean Medicine for Obesity Research
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• v.7 no.1
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• pp.55-69
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• 2007

Objectives : The aim of the study was to investigate the principal symptoms and a syndrome differentiation in the obesity using surveys from Oriental medical doctors and obese patients. Methods : Seventy three Oriental medical doctors who participated in the 2006 autumn annual conference of Korean Oriental Association for Study of Obesity and 243 obese patients responded to the survey. Results : Twenty nine percent of Oriental medical doctors replied that the syndrome differentiation is the most important diagnosis index, and 21 percent of them replied they use Sasang Constitution classification during diagnostic process. The syndrome differentiations used were mainly phlegm-fluid, blood stasis, spleen vacuity, food accumulation, damp phlegm, and Gi deficiency order. In the response of doctors and patients about principle symptoms of 6 syndrom differentiation belong inside 5 place except phlegm fluid and liver stasis Conclusions : We should develop syndrome differentiation questionnaire about obese symptoms.

• Korean Journal of Ichthyology
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• v.28 no.1
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• pp.47-51
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• 2016

Three specimens of Abudefduf septemfasciatus were collected firstly from tidal pools on the southern and northern coasts of Jeju Island, Korea in August 2015. This species is characterized by black blotches on the upper origin of the pectoral fin, upper caudal peduncle and a dorsal fin between the second and fourth spines, predorsal scales beyond to above the middle of the eye, 12~13 soft dorsal and anal fin rays, and 20 lateral-line scales. This species is distinguishable from Abudefduf sordidus by soft dorsal and anal fin rays, location of caudal peduncle blotch, and location of the dorsal fin blotch. The newly proposed Korean name is "Il-gop-jul-ja-dom".

• Journal of Korea Multimedia Society
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• v.7 no.11
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• pp.1571-1579
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• 2004

Recently, FD(Frame Dropping)-CD(Coefficient Dropping) transcoding is considered mainly due to the low computational complexity and simple implementation. But, CD errors in the FD-CD transtoding scheme tend to be propagated and they have a significant effect on the qualities of decoded images. In this paper, we derive the error characteristics incurred by the CD operations and propose an effective estimation model that adaptively describes well the characteristics of propagation/accumulation errors in compressed domain. Furthermore, we apply the proposed model to distortion control achieving nearly constant distortion allocation among frames. Simulation results show that the proposed model is quite accurate in estimating the overall distortions and is effectively applied to distortion control over a range of sequences with varying scene types.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.8
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• pp.1928-1936
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• 1996

In this paper, we propose an adaptive bandwidth allocation algorithm for the transmission of VBR video through ATM Networks. In order to evaluate the required bandwidth for the VBR video, the characteristics of the compressed VBR video generated by the two-layered coder are analyzed with variations in the number of GOP(N), quantizer scale(q), and the number of low-frequency DCT coefficients(.betha.). The two-layer coder which is used to separate from the number of DCT coefficients is designed to transmit the VBR video efficiently. The compressed data generated by the two-layer coder are splitted into the high priority and low priority cells. If congestion is occurred in ATM networks, the minimum image quality is maintained by the high priority cells. The required bandwidth for VBR video is estimated with a prediction algorithm using the scene anframe correlations as well as the statistical properties of the VBR video sources. Strong correlation among the adjacent slices in a frame represents by the scene correlation andstrong correlation among the frames is represented by the frame correlation. The performance of the bandwidth allocation scheme proposed is evaluated in terms of the bandwith utilization, cell loss rate, and SNR with variations in q, n, .betha.. Simulation rewsults shown that the proposed scheme is superior to the conventional methods.

• The Korean Journal of Food And Nutrition
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• v.23 no.2
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• pp.258-268
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• 2010

This study was conducted to examine the hypoglycemic effects of complexcity extract(DB 55) from five oriental medicinal plants on the intake of food, body weight, blood glucose level, insulin content, serum GOP, GPT, BUN and hematocrit value in streptozotocin(STZ)-induced diabetic rats. General nutritional composition was also assessed. Thirty- five male Sprague-Dawley rats were assigned to five groups : normal control group(NC), STZ-diabetic control group (STZ-control), STZ-diabetic DB-1 group(DB 55-1), STZ-diabetic DB-2 group(DB 55-2) and STZ-diabetic DB-3 group(DB 55-3). The animals were fed an experimental diet for 12 weeks. Body weight gain of the STZ-diabetic group was significantly lower but diet intake was significantly higher than the NC group. Blood glucose levels of the DB-1, DB-2 and DB-3 rats were significantly lower than the STZ-control animals. Insulin level of STZ-control rats was lower than the NC serum GOT, GPT and BUN levels were significantly higher in the NC group, but hematocrit value was not significant as compare to the STZ-diabetic group. Blood glucose level was lower observed for the DB 55-1, DB 55-2 and DB 55-3 group. The results will be useful in oriental diet therapy and in the developing functional food resources.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.9A
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• pp.2289-2304
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• 1998

For the performance analysis and traffic control of ATM networks carrying video sequences, need an appropriate video traffic model. In this paper, we propose a new traffic model for MPEG compressed videos which are widely used for any type of video applications at th emoment. The proposed modeling scheme uses scene-based traffic characteristics and considers the correlation between frames of consecutiv GOPs. Using a simple scene detection algorithm, scene changes are modeled by state transitions and the number of GOPs of a scene state is modeled by a geometric distirbution. Frames of a scene stte are modeled by mean I, P, and B frame size. For more accurate traffic modeling, quantization errors (residual bits) that the state transition model using mean values has are compensated by autoregressive processes. We show that our model very well captures the traffic chracteristics of the original videos by performance analysis in terms of autocorrelation, histogram of frame bits genrated by the model, and cell loss rate in the ATM multiplexer with limited buffers. Our model is able to perrorm translations between levels (i.e., GOP, frame, and cell levels) and to estimate very accurately the stochastic characteristics of the original videos by each level.