• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.4
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• pp.855-869
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• 1997

In this paper, we proposed two kids of dynamic priority control mechanisms controlling the cell service ratio in order to improve the QOS(Quality of Service). We also analyse theoretically the characteristics of cell loss probability and mean cell delay time by applying the proposed priority control mechanisms to ATM switch with output buffer. The proposed priority control mechanisms have the same principles of storing cells into buffer but the different principles of serving cells from buffer. The one is the control mechanism controlling the cell service ratio according to the relative cell occupancy ratio of buffer, the other is the control mechanism controlling the cell service ratio according to both the relative cell occupancy ratio of buffer and the average arrival rate. The two service classes of our concern are the delay sensitive class and the loss sensitive class. The analytical results show that the proposed control mechanisms are able to improve the QOS, the characteristics of cell loss probability and mean cell delay time, by selecting properly the relative cell occupancy ratio of buffer and the average arrival rate. conventional DLB algorithm does not support synchronous cells, but the proposed algorithm gives higher priority to synchronous cells. To reduce synchronous cell loss rate, the synchronous cell detector is used in the proposed algorithm. Synchronous cell detector detects synchronous cells, and passes them cells to the 2nd Leaky-Bucket. So it is similar to give higher priority to synchronous cells. In this paper, the proposed algorithm used audio/video traffic modeled by On/Off and Two-state MMPP, and simulated by SLAM II package. As simulation results, the proposed algorithm gets lower synchronous cell loss rate than the conventional DLB algorithms. The improved DLB algorithm for multimedia synchronization can be extended to any other cells which require higher priority.

• Korean Journal of Applied Biomechanics
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• v.13 no.1
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• pp.95-108
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• 2003

The purposes of this study were to analyze the muscle activities and the characteristics of muscle recruiting patterns of upper trunk for Ssirum dutguri technique using three top-ranked elite Ssirum players. The EMG technique was used to record muscle activities of both right and left sides of latissimus dorsi, biceps brachii, and erector spinae. Six surface electrodes were placed on the surface of the selected muscles and one ground electrode was also attached on the back of neck(C7). One video camera was also used to record the Ssirum motion to define 4 events and 3 phases for further analysis. The raw EMG data were filtered with band pass filter (50-400 Hz) to remove artifacts and then low pass filtered (4 Hz) to find the linear envelope which resemble muscle tension curve. This filtered EMG data were normalized to MVIC for the purpose of comparion between the subjects. The results were indicated that each subject with different physical characteristics showed very different muscle activity patterns. Although Ssirum dutguri is considered as foot technique the player grasped opponent's satba(belt) with both hands when they play. Because of this reason, activities of upper trunk muscles were relatively high. However, direct comparison between upper and lower body muscles was not possible due to the lack of the data in present study. Interestingly, all threes subjects showed that erector spinae muscle activity was comparatively higher than those of latissimus dorsi and biceps brachii. This implies to reinforce back muscle as a routine of training to improve performance or to prevent back injury.

• Korean Journal of Applied Biomechanics
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• v.23 no.2
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• pp.99-108
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• 2013

The purpose of this study was to analyze the kinematic characteristics of javelin to compare the characteristics between world elite athletes and local male athletes. The subjects selected 9 athletes out of total 13 athletes recorded more than 65 m in the preliminary and main competition participated in the 93rd National Sports Festival held in 2012. Three-Dimensional motion analysis using a system of 4 video cameras(Sony HXR-MC2000) at a sampling frequency of 60 fields/s was performed for this study. The Kwon3D 3.1 was used to obtain the three dimensional coordinates about the top, grip, end of javelin. And the kinematic factors of javelin calculated using Matlab2009a program. The resultant speed of javelin that affects directly to the record of performance showed 26.08 m/s indicated lower speed of about 2-3 m/s than world elite athletes. The release point appeared to have been made at the high of $1.79{\pm}0.07$ m of 99.8% of the height of the athletes. In terms of release angle, it was indicated average $33.0{\pm}3.81^{\circ}$ lower release angle compared to the world elite athletes. The attitude angle(up & down tilt angle, X axis) related to javelin indicated average $38.5{\pm}4.96^{\circ}$, its related attack angle average $5.5{\pm}5.11^{\circ}$, and yaw angle(sideslip, side attack angle) average $15.7{\pm}8.48^{\circ}$.

• Korean Journal of Applied Biomechanics
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• v.23 no.3
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• pp.189-200
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• 2013

The purpose of this study was to compare the kinematic analyses of the women's pole vault skills difference between skilled group (1st to 8th place) and less skilled group (10th to 15th place) who participated in IAAF World Championships Daegu 2011. To achieve this goal, 16 women's pole vault player's kinematic analyses was conducted. Player's best performance was recorded by five normal video cameras operating at 60 Hz. The results of this study through the research procedures above are as follows. First, Skilled group's average step length and the ratio of step length to her height were longer than less skilled's group in run-up phase. Second, Skilled group's horizontal velocity was faster than less Skilled group's results. And pole plant angle was lower than less Skilled group's results in take-off phase. Third, Maximum pole flexion angle did not show difference of between two groups in pole bending phase. However, Skilled group's vertical velocity was higher than less skilled group's results.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.3
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• pp.240-246
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• 1995

The responses of red tile fish, Branchiostegus Japonicus to a longline gear were examined in an experimental tank using two video cameras, in order to know hooking mechanism and improve longline hook. In attraction stage, the fish swim to upstream direction slowly just above the bottom toward the baited hook. The majority of the fish then biting the bait incompletely, after the biting, the fish made a backward swimming with low intense, and the bait was usually spitting out when snood was stretched. In most case, hooking took place at the moment the fish made jerk or rush after the bait wallowed. The behaviour sequence closely related to hooking are chewing and jerking or chewing and rushing. According to the field experiments, the tested hooks of long shank show very low catching efficiency compared to the traditional hook with short shank, and the hooked position of the traditional hooks were oesophagus or stomach but the tested hooks were mouth in the most cases. For catching efficiency, desirable hook shape were inferenced inner-curved point and short shank because its ease to swallow. The shape and demensions of a porposed hook were determined in consideration of mechanized gear handling and hooking performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2326-2333
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• 2009

In the adaptable bandwidth allocation technique, a transmission plan for variable rate video data is made by smoothing algorithms such as CBA algorithm and the data is sent by the transmission plan considering network traffic. But the CBA algorithm, the MCBA algorithm, MVBA algorithm and the other smoothing algorithms produce a transmission plan where the size of the increasing interval of transmission rate is generally larger than the size of the decreasing interval. And the transmission rate in CBA algorithm, the MCBA algorithm, the MVBA algorithm is changed in overflow curve during the increasing interval of transmission rate. This may cause many frames to be discarded when available transmission rate is larger than transmission rate by the transmission plan. In this paper, the smoothing algorithm, where transmission rate is changed in the middle of underflow curve and overflow curve to decrease the number of discarded frames, but the transmission rate increases at the minimum, and the CBA algorithm, the MCBA algorithm, the MVBA algorithm are applied to a transmission plan in the adaptable bandwidth allocation technique, and the minimum frame rates, the average frame rates, the variation of frame rates, and the numbers of discarded frames are compared in among algorithms.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.9
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• pp.2280-2289
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• 2009

The death rate of pedestrians in car accidents in Korea is about 2.5 times higher than the average of OECD countries'. If a system that can detect pedestrians and send alarm to driver is built and reduces the rate, it is worth developing such a pedestrian detection system (PDS). Since the accident rate in which pedestrians are involved is higher at nighttime than in daytime, the adoption of nighttime PDS is being standardized by big auto companies. However, they are usually using expensive night visions or multiple sensors for their PDS. In this paper we propose a method for nighttime PDS using a monochrome visible spectrum camera. We could verify its superiority in both performance and real?time operation to existing algorithm through tests against video data taken in several different environments.

• Journal of Korea Multimedia Society
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• v.11 no.4
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• pp.481-491
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• 2008

As the T-DMB (Terrestrial Digital Multimedia Broadcasting) has been actively launched, all the service providers are focusing on finding a new business model using a variety of data services as well as video service. The middleware technology for data broadcasting service, which was presented due to such necessity, known as DMB MATE (Mobile Application Terminal Environment), provides a running environment of the applications and APIs so that the various data applications can support high-level functionalities for the interactive data service. In this paper, in order to effectively provide the data service under restricted channel environment of T-DMB, we introduce a service technology and an interactive data broadcasting system using the DMB MATE, specifically proposing a design method of T-DMB MATE receiver capable of the presented DMB MATE service. Finally, the performance of developed system is confirmed through the T-DMB data broadcasting experiment under a variety of conditions.

• Journal of the Institute of Convergence Signal Processing
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• v.16 no.4
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• pp.129-133
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• 2015

In this paper, we propose a fast motion estimation algorithm which is important in the performance of video encoding. Conventional fast motion estimation algorithms have serious problems of low prediction quality in some frames and still much computation. In the paper, we propose an algorithm that reduces unnecessary computations only, while keeping prediction quality almost similar to that of the full search. The proposed algorithm uses distribution of probability of motion vectors, divides search range into several groups according to its importance, and applies adaptive block matching criteria for each group of search range. The proposed algorithm takes only 3~5% in computational amount and has decreased prediction quality about 0~0.01dB compared with the fast full search algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.6
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• pp.1129-1135
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• 2007

Human face detection technique plays an important role in computer vision area. It has lots of applications such as face recognition, video surveillance, human computer interface, face image database management, and querying image databases. In this paper, a fast face detection approach using Principal Component Analysis (PCA) and Support Vector Machines (SVM) is proposed based on the previous study on face detection technique. In the proposed detection system, firstly it filter the face potential area using statistical feature which is generated by analyzing the local histogram distribution the detection process is speeded up by eliminating most of the non-face area in this step. In the next step, PCA feature vectors are generated, and then detect whether there are faces present in the test image using SVM classifier. Finally, store the detection results and output the results on the test image. The test images in this paper are from CMU face database. The face and non-face samples are selected from the MIT data set. The experimental results indicate the proposed method has good performance for face detection.