• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5A
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• pp.500-508
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• 2008

Direct-sequence ultra-wideband(DS-UWB) system is being considered as one of promising transmission technologies for wireless personal area networks(WPANs). Due to relatively low spreading factors and huge bandwidth of transmit signal, a DS-UWB receiver needs to be equipped not only with a rake receiver but also with an equalizer, of which the equalizer is not required for traditional direct-sequence code division multiple access(DS-CDMA) systems. The number of rake fingers is limited in practice, influencing the performance of the subsequent equalizer. In this paper, we derive a decision feedback equalizer(DFE) for DS-UWB systems based on the minimum mean square error(MMSE) criterion, and investigate the impact of various parameters on the DFE performance in realistic scenarios. In particular, we propose an approach to improving the performance of the DFE using additional channel estimates for multipaths not combined in the rake receiver, and discuss how the accuracy of channel estimation affects desirable DFE configuration. Moreover, we present simulation results that show the impact of turbo equalization on the DFE performance.

• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.10-15
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• 2005

In the area of mobile communication, Location Based Services (LBS) using the location of mobile terminal to provide their services are rapidly spreading as communication network and terminal evolves. Despite the LBS are highly demanded in high speed internet area, the services are very rare due to the difficulty locating terminals. In this paper, we propose the method to locate terminals in real time and describe its implementation system. The proposed system is designed to collect the information in real time for more than a terminal connecting internet. And, the system shows high performancecollecting and generating location information through simulation tests.

• The Korean Journal of Pain
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• v.7 no.1
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• pp.116-118
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• 1994

Neurolytic splanchnic nerve block is effective for treatment of intractable upper abdominal cancer in. The possibility of neurologic complication cannot be completely precluded. A 53 year-old female patient with hepatoma and lung metastasis was submitted for splanchnic nerve block with alcohol. Splanchnic nerve block was performed under radiologic control by image intensifier without any difficulty during procedure. One day after the block, she complained of numbness with sensory deficit in bilateral inguinal area. Neurologic examination revealed that asymmetrical anesthesia, hypoesthesia at $T_{12}-L_2$. She was discharged 70 days after the block with partial improvement. The possibility of alcohol spreading to the low theracic and upper lumbar somatic nerves cannot be excluded.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.58-58
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• 2022

With the development of advanced technology, automation of agricultural work is spreading. In association with the 4th industrial revolution-based technology, research on field smart farm technology is being actively conducted. A state-of-the-art unmanned automated agricultural production demonstration complex was established in Naju-si, Jeollanam-do. For the operation of the demonstration area platform, it is necessary to build a sophisticated, advanced, and intelligent field smart farming model. For the operation of the unmanned automated agricultural production demonstration area platform, we are building data on the growth of soybean for smart cultivated crops and conducting research to determine the optimal time for agricultural work. In order to operate an unmanned automation platform, data is collected to discover digital factors for water management immediately after planting, water management during the growing season, and determination of harvest time. A subsurface drip irrigation system was established for smart water management. Irrigation was carried out when the soil moisture was less than 20%. For effective water management, soil moisture was measured at the surface, 15cm, and 30cm depth. Vegetation indices were collected using drones to find key factors in soybean production prediction. In addition, major growth characteristics such as stem length, number of branches, number of nodes on the main stem, leaf area index, and dry weight were investigated. By discovering digital factors for effective decision-making through data construction, it is expected to greatly enhance the efficiency of the operation of the unmanned automated agricultural production demonstration area.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.201-210
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• 2019

Recently, due to the efforts to mitigate traffic congestion and expansion of space efficiency, the construction of underground roads has been increased in big-scale cities. Since tunnels in the city have a higher chance for a fire leading to a great tragedy during a severe traffic jam than mountain tunnels, it is highly likely that it will be constructed as a tunnel, having a small cross section, for small vehicles. However, if they are constructed as such small-vehicle tunnels, it would be possible to reduce the design fire intensity while the concentration of harmful gases would increase due to a reduction in the small cross sectional area, led by a decrease in the tunnel height. In this study, behaviors of fire smoke by the installation interval and format of large-scale exhaust-gas ports were examined and compared in the analysis of temperatures and CO concentrations of a tunnel and its results were as the following. Although there were no significant differences in the smoke spreading distance between installation intervals, but in this study, 100 m was found to be the most effective installation interval. The smoke exhaustion performance was found to be excellent in the order of $4m{\times}3m$, $6m{\times}2m$, and $3m{\times}2m$ (2 lane) of the smoke spreading distance. Although there was no significant difference in the smoke spreading distance between formats of large-scale exhaust-gas ports, it was found that the smoke spreading distance was larger than other cases when it was $3m{\times}2m$ in the fire growing process. The analysis of smoke spreading distances by the aspect ratio showed that a smoke spreading distance was shorted when its the smoke spreading distance was found to be shorter when its traverse distance was relatively longer than its longitudinal distance.

• Journal of Biosystems Engineering
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• v.36 no.6
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• pp.397-406
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• 2011

In this study, surveys on operation status of the 73 tractors with rated power of over 75 kW from six provinces in Korea were performed to obtain basic data required for development and efficient use of the high-power and high-performance tractors. And types of tractors and implements, operation crops, types of operations, annual operation areas, annual operation days, annual operation hours, operation speeds and widths, and problems and improvements in use were investigated. Most (91.7%) of the tractor surveyed were operated for forage and silage crops such as rice straw, whole barley, rye grass, reed canary grass, sudan grass, and the remains were operated for upland crops such as ginseng, sweet potato, potato, chinese cabbage, radish. Main operations of the tractors were cutting, baling, and wrapping for forage crops, plow tillage, rotary tillage, and manure spreading. About half (47.9%) of the tractors were used exclusively for forage crop harvesting such as forage crop cutting, forage baling, and bale wrapping, 24.5% of the tractors were used exclusively for plow or rotary tillage, and 27.4% of the tractors were used for both forage crop harvesting, and plow or rotary tillage. For the tractors with power ranges of 75~83, 89~94, 98~101, 113, 124 kW, average annual operation areas per tractor for plow tillage, rotary tillage, forage crop harvesting (cutting, baling, wrapping), and manure spreading operations were analyzed as 112.6. 144.8, 158.9. 390.0. 215.6 ha, respectively. and total average annual operation area per tractor was 171.3 ha. Average annual operation days per tractor for those operations were analyzed as 24.1, 28.9, 38.3, 55.4, 33.4, respectively, and total average annual operation days per tractor was 33.6. Average annual operation hours per tractor for them were analyzed as 260.0, 321.6, 408.1, 664.8, 413.8, respectively, and total average annual operation hours per tractor for the all tractors was 377.1. Ranges of operation widths of plow tillage, rotary tillage, forage crop cutting, forage baling, bale wrapping, and manure spreading operations were shown as 1.5~2.6, 2.3~3.0, 1.8~3.2, 1.8~2.0, 1.8~2.3, 3.1~6.6 m, respectively. Ranges of operation speed of plow tillage, rotary tillage, forage crop cutting, forage baling, bale wrapping, and manure spreading were shown as 6~9, 4~11, 9~16, 8~15, 8~17, 12~16 km/h, respectively.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.4
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• pp.101-119
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• 2020

Recently, as a plan to improve the particulate matter and thermal environment in the city, urban forests acting as wind ventilation corridor(wind ventilation forest) are promoted nationwide. This study analyzed the conditions for the creation of wind ventilation forest(vulnerable areas of the particulate matter and thermal environment, distribution of wind ventilation forest, characteristics of ventilation corridor) of in Pyeongtae-si, one of the target cities of wind ventilation forest project. Based on the results, the direction of developing on the wind ventilation forest in Pyeongtaek-si was suggested. As a result of deriving areas vulnerable to particulate matter and thermal environment, it was most vulnerable in urban areas in the eastern area of Pyeongtaek-si. Especially, emissions were high from industrial complexes and roads such as the Pyeongtaek-si thermal power plant, ports, and the national road no. 1. The wind ventilation forest in Pyeongtaek-si was distributed with small-scale windgenerating forests, wind-spreading forests, and wind-connection forests fragmented and disconnected. The characteristic of the overall wind ventilation corridor in Pyeongtaek-si is that the cold air generated from Mt.Mubong, etc., strongly flowed into Pyeongtaek-si and flowed in the northwest direction. Therefore, it is necessary to preserve and expand the wind-generating forests in Pyeongtaek-si in the long term, and it was important to create wind-spreading forests and wind-connection forests so that cold air could flow into the vulnerable area. In addition, in industrial complexes and roads where particulate matter is generated, planting techniques should be applied to prevent the spread of particulate matte to surrounding areas by creating wind-spreading forests considering the particulate matter blocking. This study can be used not only as the basis data for wind ventilation forest project in Pyeongtaek-si, but also as the basis data for urban forest creation and management.

• Journal of Environmental Science International
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• v.17 no.6
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• pp.601-609
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• 2008

In this study for the development of area due to the increasing of industry, population and spreading of urbanization is rapidly increasing but about seventy percent of our nation's areas consists of the mountainous districts. In such case, when those areas have the heavy rains break, they are washed away by a fast-flowing stream of a valley and overflowed. Thus it could result on human life and property damage and also the widespread of flood damage in the downstream area. To decrease those damage, the construction of flood control reservoir is necessary. This research was aim to construct the flood runoff models of a mountainous small district and to determine the probability rainfall by analyzing precipitation. The study also examined the effects of location and size of flood control reservoir on flood reduction. The result showed that the construction of detention basin was an effective way to ensure the safety of flood control and multiple detention basin had superior result for reducing amount of runoff in the down stream area than the single detention basin.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.2
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• pp.914-922
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• 2019

Gas composition has a significant impact on the dispersion behavior and accumulation characteristics of blowout gas. However, few public studies has investigated the corresponding effect of gas composition. Therefore, this study firstly builds the FLACS-based numerical model about an offshore drilling platform. Then several scenarios by varying the composition of blowout gas are simulated while the scenario with the composition of "Deepwater Horizon" accident is regarded as the benchmark. Furthermore, the effects of the gas composition on the flammable cloud volume, the influenced area of flammable cloud, the influenced area of hydrogen sulfide and the critical time of the hydrogen sulfide spreading to the living area are analyzed. The results demonstrate that gas composition is a driving factor for dispersion characteristics of blowout gas. All the results can give support to reduce the risk of the similar accidents incurred by real blowouts.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1246-1248
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• 2003

Internal wave with a soliton-like, large amplitudes within several kilometers, is frequently observed in the sea surface caused by tidal rectification due to sill or rough topographic changes. Internal waves can perturb current and density field, initiate bottom sediment re -suspension and mix nutrients to photic zone. Previous studies indicate that the appearance of internal wave in the Lombok Strait have been detected in SAR image data. This paper studies effect of internal wave in the Lombok Strait to chlorophyll distribution in the surrounded areas using SeaWiFS and ERS SAR images data during 1996-2001 periods. The preliminary result concludes that the internal waves presumably affect phytoplankton distribution spreading southeastward in the coast off Bali Island. The distribution of phytoplankton at southern coastline off Bali Island when internal wave occurred is elongated and distributed further to westward (from 8.8$^{\circ}$ to 10.7$^{\circ}$LS) than the area when internal wave did not occur on August 2000 (from 9.25$^{\circ}$ to 10.25$^{\circ}$LS) as shown in figure 3. It shown that the surface phytoplankton concentration near coastal area, i.e. from 8.8$^{\circ}$ to 9.25$^{\circ}$ LS, increased when internal wave is occurred.