• Atmosphere
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• v.29 no.4
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• pp.429-438
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• 2019

Organic carbon (OC) and elemental carbon (EC) in PM_2.5 were measured with Sunset Laboratory Model-5 Semi-Continuous OC/EC Field Analyzer by NIOSH/TOT method at Anmyeondo Global Atmosphere Watch (GAW) Regional Station (37°32'N, 127°19'E) in July and August, 2017. The mean values of OC and EC were 3.7 ㎍ m^-3 and 0.7 ㎍ m^-3, respectively. During the study period, the concentrations of reactive gases and aerosol compositions were evidently lower than those of other seasons. It is mostly due to meteorological setting of the northeast Asia, where the influence of continental outflow is at its minimum during this season under southwesterly wind. While the diurnal variation of OC and EC were not clear, the concentrations of O₃, CO, NOx, EC, and OC were evidently enhanced under easterly wind at night from 20:00 to 8:00. However, the high concentration of EC was observed concurrently with CO and NOx under northerly wind during 20:00~24:00. It indicates the influence of thermal power plant and industrial facilities, which was recognized as a major emission source during KORUS-AQ campaign. The diurnal variations of pollutants clearly showed the influence of land-sea breeze, in which OC showed good correlation between EC and O₃ in seabreeze. It is estimated to be the recirculation of pollutants in land-sea breeze cycle. This study suggests that in general, Anmyeondo station serves well as a background monitoring station. However, the variation in meteorological condition is so dynamic that it is primary factor to determine the concentrations of secondary species as well as primary pollutants at Anmyeondo station.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.7
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• pp.99-109
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• 2012

Sub-station, key equipment in electric power infrastructure, are being exposed to increasing risk of hacking. For this, soft redundancy sub-station system needs to be formulated with automatic restoration mechanism. For this it is important to assess the reliability of the applicable range of data that are used in actual system operation, as well as the methods and findings of the tests. At the same time performance of soft redundancy system and total security mechanism, which are aligned for the protection of the sub-station, need to be tested. For testing the above-mentioned, this paper presented a viable formation of a soft redundancy practical VPN system within a panel to protect the latter from hacking or cracking incidences, and conducts a test to check if the considered system actually serves the protection function in the actual operation setting, gathering evidence from the data from the testing of the actual performance of the system as well as of emergency scenario simulation operations. Because tested soft-redundancy & restorative sub-station system is expected to be widely applicable for various cases such as Smart-grid or electricity IT system, where VPN with enhanced level of security is required.

• Journal of Forest and Environmental Science
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• v.38 no.2
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• pp.75-89
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• 2022

The negative impact of monoculture rubber plantations on biodiversity and associated ecological processes/ecosystem services has led to suggestions on the use of integrated land use systems for rubber cultivation and production in order to ensure environmental sustainability. However, there is paucity of information on the effect of such integrated land use systems on the diversity and abundance of the rubber plantation undergrowth. We evaluated and compared undergrowth plant species composition, richness, abundance, diversity and interaction, in three integrated systems (Rubber-Strelitzia reginae Integrated System - RSrIS, Rubber-Podocarpus nagi Integrated System - RPnIS & Naturally Managed Rubber Plantation - NMRP) with three Rubber Monoculture Plantations (RMP₁, RMP₂ & RMP₃) adjacent to the integrated systems, respectively, at the Investigation and Experiment Station of Tropical Crops, Danzhou, Hainan, China. Undergrowth species density was higher in the rubber monocultures than in the integrated systems except in RSrIS. Species richness and diversity were also higher in the monocultures except in NMRP. Species similarity/interaction between the monocultures and the integrated systems was highest between RMP₃ and NMRP. The NRMP proved to be the best model of natural rubber integrated system for the conservation of undergrowth species richness, diversity and interspecific interaction. However, the conservation of undergrowth species in other forms of integrated natural systems can be enhanced by considering the ecology of species to be integrated in terms of their growth characteristics, competitive nature, and ability to grow in association with other species.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.15-22
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• 2006

In OFDMA system, even if the number of allocated sub-channel in mobile station varies from one to the whole sub-channel as in base station, while because of mobile station's transmit power is lower than that of base station, therefore full loading range(FLR) constraint occurs where whole sub-channel can be used and the conventional open-loop power control scheme can not be used beyond FLR. We propose a new scheme that limits the maximum sub-channel allocation number and uses power concentration gain(PCG) depending on location of mobile station, which is based on ranging in OFDMA system. Simulation results show that the proposed scheme provides solutions for optimum utilization of radio resource depending on the location of mobile station and enables open-loop power control beyond FLR without extra hardware complexity.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1380-1381
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• 2008

By applying the digital sub-station, the change of various protect and measuring equipments has been applying. This paper is analyzed that the development of GIS partial discharge condition monitoring equipment is suited to the electricity IT technology and digital sub-station. It's constitution apply to be able to suit the data to high rank for GIS partial discharge condition monitoring equipment that is suited digital sub-station and Watch-dog module that be able to monitor the inner communication of the GIS partial discharge equipment. And then it also be able to apply of GIS partial discharge equipment when digital sub-station is applied.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.53-55
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• 2005

In electrical railway system, power supplied to electrical locomotive by catenary is returned to sub-station on track. The current returned to sub-station on track is return current, which is an essential factor for the safety of the wayside electrical equipment and maintenance staff. Therefore, earth system acts an important role to protect wayside electrical equipment and maintenance staff against return current. In general, individual earth system protects partially the electrical railway system, but common earth system does the whole electrical railway system and minimizes the flow of return current. In this paper, we are compared the effect of return current according to earth type by actual measurement in existing electrical railway system. The measurement was conducted at Shinchungju sub~station in high speed trains, and Guro sub-station, which is electrified section in classical line.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.21 no.4
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• pp.17-26
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• 2013

In this paper, a configuration procedure of a transportation infrastructure system for GNSS based very precise real-time positioning is proposed. This infrastructure system consists of several receiving station, a central station, and communication sub-systems. The required performance, design, implementation and verification of each sub-system are explained respectively. The required performance can be broken down into accuracy, integrity, stability, processing time. The design of the each sub-system is performed in accordance with the required performance and each sub-system is built with regard to the design. Lastly the implemented system is verified in comparison with the required performance.

• International Journal of Industrial Entomology and Biomaterials
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• v.7 no.2
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• pp.107-115
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• 2003

The present paper deals with the mulberry cultivation technology with package of practices for successful sericulture in Indian sub-tropics. The information on leaf nutritional quality in trained and untrained trees is provided. Besides, the current status of sericultural practices is discussed based on the problems faced by the industry and intensive field surveys undertaken in different areas of one of the most potential sericultural provinces.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.5A
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• pp.414-420
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• 2009

In this paper, we investigate throughput performance of OFDMA-based relay systems according to the "sub-cell coverage configuration" of the base station (RS) and the relay station (RS). RS is exploited for improved quality of the received signal with a tradeoff of additional radio resource consumption which may result in degradation of the throughput performance of the system. Therefore, "radio resource reuse" may be necessary for high performance in relay systems. However, it also causes system performance degradation since resource reuse between RSs incurs channel interference. Therefore, effective resource reuse also should be considered for "high throughput coverage configuration" when relays are employed. We relate the resource reuse patterns of neighboring RSs to sub-cell coverage configuration. We determine the sub-cell coverage of the system depending on the ratio of received signal-interference-noise-ratio (SINR) of the mobile station (MS) from the BS and RS, respectively. Simulations illustrate the throughput performance as the function of SINR ratio, and it has different optimal point depending on the resource reuse patterns. Therefore, the "resource reuse pattern" and the "effective sub-cell coverage configuration" should be considered together for the high throughput performance of the relay system.

• Animal Bioscience
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• v.37 no.2
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• pp.173-183
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• 2024

Objective: This study aimed to evaluate whether the methane (CH₄) to carbon dioxide (CO₂) ratio (CH₄/CO₂) and methane-related traits obtained by the sniffer method can be used as indicators for genetic selection of Holstein cows with lower CH₄ emissions. Methods: The sniffer method was used to simultaneously measure the concentrations of CH₄ and CO₂ during milking in each milking box of the automatic milking system to obtain CH₄/CO₂. Methane-related traits, which included CH₄ emissions, CH₄ per energy-corrected milk, methane conversion factor (MCF), and residual CH₄, were calculated. First, we investigated the impact of the model with and without body weight (BW) on the lactation stage and parity for predicting methane-related traits using a first on-farm dataset (Farm 1; 400 records for 74 Holstein cows). Second, we estimated the genetic parameters for CH₄/CO₂ and methane-related traits using a second on-farm dataset (Farm 2; 520 records for 182 Holstein cows). Third, we compared the repeatability and environmental effects on these traits in both farm datasets. Results: The data from Farm 1 revealed that MCF can be reliably evaluated during the lactation stage and parity, even when BW is excluded from the model. Farm 2 data revealed low heritability and moderate repeatability for CH₄/CO₂ (0.12 and 0.46, respectively) and MCF (0.13 and 0.38, respectively). In addition, the estimated genetic correlation of milk yield with CH₄/CO₂ was low (0.07) and that with MCF was moderate (-0.53). The on-farm data indicated that CH₄/CO₂ and MCF could be evaluated consistently during the lactation stage and parity with moderate repeatability on both farms. Conclusion: This study demonstrated the on-farm applicability of the sniffer method for selecting cows with low CH₄ emissions.