• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.2
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• pp.73-88
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• 2000

A series of analysis and experiment on the fishing gear and method of the existing midwater pair trawl net with 12,800mm of maximum mesh size is carried out to determine the most effective shape factor. As the first step of this study, the fishing gear and method for the existing net are analyzed to solve problems, such as being low of the net height by increasing the towing speed, twist of net pendant and twine, suspension of float between knots of mesh. etc. Standing on these results, the existing net are modified by very effective shape based on the theory and technology designing the fishing gear. Also, the model experiment is carried out to determine the most effective shape factor of the modified net in the circulation water channel. The obtained results can be summarized as follows : 1. On the length of net pendants(No.2 and No.3) connected with side line, opening efficiency of net with length 8.0cm of net pendant is the greatest and in the order of 11.5cm, 15.0cm. 2. On the number of the net pendant, opening efficiency of net with 4 lines of net pendant is the greatest and in the order of 3 lines, 2 lines. Center part of side panel is pushed out backward, and the pushed length is increasing by increasing flow speed. 3. On the sinking force, opening efficiency of the net is increasing by increasing sinking force. And opening efficiency shows almost the same when sinking force is greater about 1.5 times than that of the existing net in case of the net with 3 lines of net pendant, and about 1.6 ~ 1.7 times than that of the existing net in case of the net with 2 lines.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.43 no.2
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• pp.101-115
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• 2007

The pound net fishery is very important one in Korean coastal fishery and it need to grasp the characteristics of the net affected by many factors. It is considered that the structure and the shape of the pound net can be changed by the direction and speed of current, wave height, depth and conditions of sea bed. However, most of all, the speed of current and wave height influence more upon the pound net than any other factors to deform and flutter. In this study, author carried out the experiments with a model of double one-side pound net made by the similarity law as 1:100 scales at a real experimental area, and additionally the model net experiments were conducted in the circulating water channel in Pukyong National University. The author analyzed the data of transformation of shape and tension of the model pound net to recognize the characteristics of the current and wave acting on it. Regardless of the direction of flow affecting on the fish court net or bag net, the deformed angle and depth to the side panel and bottom of box nets becomes bigger as the wave gets higher and the period of wave is faster. The tension in both upward or downward tends to be changed by the speed of wave. Those value of changes occurred similarly in either fish court net or bag net. Generally, when bag net is located at upward of flow, the value of tension was bigger 10% than any other location or nets. Regardless of the setting direction, the tension of the pound net is increased in proportion to flow speed, wave height and period of wave, and it becomes bigger about 15-30% at upward to flow than downward. Where the flow is upward in the court net, the tension in the wave increased to 37% compared to the one in the flow only in the condition of flow of 0.1-0.3m/s. Where the flow is upward in the bag net, the tension in the wave increased to 52% in the flow of 0.1m/s, and the tension increased to 48% in the flow of 0.2-0.3m/s.

• Journal of Broadcast Engineering
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• v.14 no.5
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• pp.561-572
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• 2009

In this paper, we propose an efficient layer-separable PES packetization and processing scheme for DVB-S2 satellite broadcasting service based on SVC video. Unlike the conventional single layer-based video coding such as MPEG-2, MPEG-4 and H.264, SVC can combine numerous number of video layers, which are aggregated to a single bitstream. Therefore, it is necessary to devise a new PES packetization scheme that can efficiently separate multiple video layers of SVC. In order to combine the layered characteristics of the SVC video and the robust channel coding capability of LDPC (Low Density Parity Check) of DVB-S2 for unequal error protection, we propose an efficient PES packetization in the transmitter side and PES packet processing scheme in the receiver side of DVB-S2. We prove the effectiveness of the proposed scheme in terms of processing speed and time delay required for processing of the separated layers of SVC video in the satellite broadcasting service.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.3
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• pp.321-331
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• 2008

A model has been constructed in this study for the investigation of physical characteristics of the Gyeonggi Bay and Han River estuary. MIKE 21 HD (HyDrodynamics) has been used for the uncertainty analysis of the tide of the Gyeonngi Bay and Han River estuary. A total of 15 model experiments have been performed for the hydrodynamic parts and the analysis of results have been made in terms of RMSD (Root-mean square deviation) which has been frequently employed in the suitability analysis of hydrological data since the introduction by NERC(1975), U.K. A smaller value of RMSD indicates the more suitability of a parameter to the model. Analysis of the hydrodynamic results has shown that RMSD of the mean tidal range has the largest value of 0.1148 at Yeomha channel while has the smallest value of 0.0400 at Yeonphyong-do, indicating that the uncertainty in the mean tidal range on near-shore side is larger than that of offshore side. Experiment with reduced water depth by 10% has produced a most significant increase in RMSD. It is therefore implied that the model response changes more sensitively to water depth rather than grid sizes, open boundary forcing and river discharge.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.1
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• pp.1-8
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• 1998

The hydrographic data collected at three different times July, 1994, May, 1995 and June, 1996 around Taean peninsula in the mid-Yellow Sea off Korea, well known for the well-defined surface thermal fronts in summer, were analyzed. In the vertically well-mixed area where water depths varied from 15 m depth to 60 m depth, the temperature difference in the water column was less than $1^{\circ}C$. The temperature observed in the vertically well-mixed area was reversely related with the water depths and the coldest surface water was always observed over the deep channel with the depth of more than 50m, which developed southwestward off the promontory of Taean peninsula, irrespective of the observation period. The strengths of surface thermal front observed in June were much stronger than those in July, even though the surface temperature of stratified area were nearly the same as in July. These observed features could be explained as follows: A major physical process for the formation of the surface thermal front is the vertical mixing of water column but the detailed thermal structure in the study area depend on the physical parameters such as the water depth in the vertically well-mixed side and the vertical thermal structure in the stratified side.

• Science of Emotion and Sensibility
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• v.5 no.4
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• pp.77-84
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• 2002

In this paper, we propose the NAVER, a general framework for multipurpose virtual environments, and introduce the case study of evaluating car prototypes using cave-like systems. As a framework to implement variant applications in virtual environment, NAVER is extensible, reconfigurable and scalable. NAVER consists of several external modules (Render Server, Control Server and Device Server), which communicate each other to share states and user-provided data and to perform their own functions. NAVER supports its own scripting language based on XML which allows a user to define variant interactions between objects in virtual environments as well as describe the scenario of an application. We used NAVER to implement the system for evaluating car prototyes in a CAVE-like virtual environment system. The CAVE-like virtual environment system at KIST consists three side screens and a floor screen (each of them is a square with side of 2.2m), four CRT projectors displays stereoscopic images to the screens, a haptic armmaster, and a 5.1 channel sound system. The system can provide a sense of reality by displaying auditory and tactile senses as well as visual images at the same time. We evaluate car prototypes in a CAVE-like system in which a user can observe, touch and manipulate the virtual installation of car interior.

• Journal of the Korean Geographical Society
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• v.42 no.1 s.118
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• pp.15-26
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• 2007

This study aims to estimate the similarities of lacustrine deposits of lava-dammed Yeoncheon paleo-lake by geochemical analysis such as XRF, ICP-AES, and 14C and OSL age datings in Chugaryeong Rift Valley of Central Korea. OSL age of the lacustrine coastal deposit(YC1) is estimated as 0.11-0.13 Ma. It indicates that paleo-deposits may have remained during at least 20,000 years from 0.13 Ma The origin analysis of deposits were carried out by comparison between lacustrine mud layers($YC1{\sim}2$) and various geomorphic materials of vicinity As a result, the similarity of the origin is highest between the paleo-coastal alluvial deposit of Chatan River(YC8), and surface clay deposit of Jeongok lava plateau(YC9) Next higher similarity is between paleo-lacustrine bottom deposit(YC2) and west valley-side mountain slope colluvial materials(YC5). Another high similarities are among present Chatan River channel sediment(YC7), acustrine coastal deposit(YC1) and east valley-side mountain slope colluvial materials(YC4).

• Tuberculosis and Respiratory Diseases
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• v.53 no.2
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• pp.221-226
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• 2002

A 58-year-old man was admitted after suffering dyspnea and pleuritic chest pain on his right side for one week. A chest X-ray revealed necrotizing pneumonia and a lung abscess on right upper lobe. Despite of antibiotics and supportive care, a complicated parapneumonic effusion developed on his right side. Closed thoracostomy was performed for drainage. However, after the thoracostomy, a bronchopleural fistula (BPF) occurred with a continuous air leak. After 30 days intensive therapy, the underlying necrotizing pneumonia and lung abscess resolved, but the BPF continued. Bronchoscopic treatment was performed because the patient was a poor candidate for surgery. After localizing the BPF with a systemic occlusion of the segmental bronchi, small strips of Gelfoam were placed in the suction channel of the flexible bronchoscopy, and either flushed with a saline solution or inserted with forceps until the cessation of air leak. The patient was discharged 10 days after the bronchoscopic treatment.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.1
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• pp.11-21
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• 2008

In conventional video coding, the complexity of encoder is much higher than that of decoder. However, as more needs arises for extremely simple encoder in environments having constrained energy such as sensor network, much investigation has been carried out for eliminating motion prediction/compensation claiming most complexity and energy in encoder. The Wyner-Ziv coding, one of the representative schemes for the problem, reconstructs video at decoder by correcting noise on side information using channel coding technique such as turbo code. Since the encoder generates only parity bits without performing any type of processes extracting correlation information between frames, it has an extremely simple structure. However, turbo decoding errors occur in noisy side information. When there are high-motion or occlusion between frames, more turbo decoding errors appear in reconstructed frame and look like Salt & Pepper noise. This severely deteriorates subjective video quality even though such noise rarely occurs. In this paper, we propose a computationally extremely light encoder based on symbol-level Wyner-Ziv coding technique and a new corresponding decoder which, based on a decision whether a pixel has error or not, applies median filter selectively in order to minimize loss of texture detail from filtering. The proposed method claims extremely low encoder complexity and shows improvements both in subjective quality and PSNR. Our experiments have verified average PSNR gain of up to 0.8dB.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.4B
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• pp.613-623
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• 2000

Digital TV tuner for 8-VSB modulation was developed with satisfying the requirements of ATSC. The double frequency conversion and the active tracking filter in the front-end were used to reduce interference of the adjacent channels and multi-channels, which suppress If beat and image band. However, it was impossible to get frequency mapping between tracking filter and first VCO(Voltage Controlled Oscillator) in the double conversion digital TV tuner differing from conventional NTSC tuner. This paper, therefore, suggests the available structure and a new method for automatic frequency selection by obtaining the mapping of frequency characteristic over tracking voltage and the combined hardware which compose of Micro-controller, EEPROM, D/A(Digital-to-Analog Converter), OP amp and switch driver to solve above problems.