• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.465-468
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• 2000

The interference situation for the satellite networks using non-geostationary satellite orbit (NGSO) is more complicated than the situation between geostationary satellite orbit (GSO) networks because of the time varying orbital characteristics of NGSO systems. Most of frequency bands are allocated to fixed-satellite service and liked-service in co-primary basis. In this paper, the sharing criteria between NGSO/FSS systems and HDFS (High Density Fixed-Service) are examined.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.385-385
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• 2006

• Journal of Satellite, Information and Communications
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• v.5 no.2
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• pp.57-63
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• 2010

Many efficient frequency sharing methods are issued in present because of increasing users with various wireless communication terminals. In the satellite communications, the service coverage is generally very wide so frequency sharing with terrestrial system is essentially needed, and the research is progressing dynamically related on this frequency sharing method. But if we adopt the terrestrial system which is commonly used, it can't avoid the interference from terrestrial service to satellite service. Therefore, this paper will introduce methods for reducing the interference from terrestrial station to earth station using cognitive radio system Satellite system is guaranteed with decreasing interference from terrestrial stations using Genetic Algorithm based power control method. Furthermore, terrestrial systems can have increased QoS because the frequency reuse factor in proposed method is higher than existing methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.8
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• pp.2140-2156
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• 2023

The Wireless Sensor Network (WSN), is constructed out of teeny-tiny sensor nodes that are very low-cost, have a low impact on the environment in terms of the amount of power they consume, and are able to successfully transmit data to the base station. The primary challenges that are presented by WSN are those that are posed by the distance between nodes, the amount of energy that is consumed, and the delay in time. The sensor node's source of power supply is a battery, and this particular battery is not capable of being recharged. In this scenario, the amount of energy that is consumed rises in direct proportion to the distance that separates the nodes. Here, we present a Hybrid Firefly Glow-Worm Swarm Optimization (HF-GSO) guided routing strategy for preserving WSNs' low power footprint. An efficient fitness function based on firefly optimization is used to select the Cluster Head (CH) in this procedure. It aids in minimising power consumption and the occurrence of dead sensor nodes. After a cluster head (CH) has been chosen, the Glow-Worm Swarm Optimization (GSO) algorithm is used to figure out the best path for sending data to the sink node. Power consumption, throughput, packet delivery ratio, and network lifetime are just some of the metrics measured and compared between the proposed method and methods that are conceptually similar to those already in use. Simulation results showed that the proposed method significantly reduced energy consumption compared to the state-of-the-art methods, while simultaneously increasing the number of functioning sensor nodes by 2.4%. Proposed method produces superior outcomes compared to alternative optimization-based methods.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.727-729
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• 2004

본 연구는 비정지궤도 이동위성 통신시스템에서 동일 셀과 인접 셀 내의 단말기들의 밀집도에 따른 채널용량을 비교 분석하였다. CDMA 셀룰라 시스템은 같은 시간에 같은 주파수를 모든 사용자들이 같이 사용하므로 자기 신호 외의 다른 사용자의 신호는 간섭으로 나타나 통신 품질에 영향을 미친다. 특히 동일 셀과 인접 셀에서 단말기의 분포 및 밀집도에 따라 통신link에서 간섭이 달라 질 수 있으며, 이는 곧 통신 채널에서 용량의 변화가 이루어 질 수 있다는 점으로 해석된다. 본 연구는 이동위성 통신시스템에서 간섭에 따른 효율적인 채널용량 분석에 유용하게 사용될 수 있을 것이다.

• Electronics and Telecommunications Trends
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• v.34 no.3
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• pp.65-74
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• 2019

The Earth Stations in Motion (ESIM) system is one of the most modern satellite systems, providing high-speed and high-capacity communication with mobility. To facilitate ESIM in the Ka band, operational, technical, and regulatory studies have been conducted in the International Telecommunication Union Radiocommunication Sector (ITU-R) since 2016. In this paper, we introduce the ESIM and discuss its system characteristics and frequency sharing issues with respect to existing services in the same frequency bands. Taking into account current standardization activity in the ITU-R, we provide the latest study results of ESIM operation based on the Conference Preparatory Meeting Report for the World Radiocommunication Conference-19.

• Food Science of Animal Resources
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• v.29 no.2
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• pp.178-187
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• 2009

This study was carried out to investigate the effects of grape seed oil on quality characteristics of pressed ham. Five different treatments were tested based on differences in the amount of grape seed oil added to the pressed ham. As a control, 10% back fat was added without any grape seed oil. For the first treatment, 10% grape seed oil replaced a portion of the lard component added to the pressed ham. For the 2nd, 3rd and 4th treatments, 20%, 30% and 40% of grape seed oil were substituted for lard, respectively. Pressed ham manufactured with grape seed oil was vacuum packaged and stored for 1, 7, 14,21 and 28 d at $4^{\circ}C$. Samples were analyzed for chemical composition, physico-chemical properties (pH, color) and texture characteristics. Typical chemical composition characteristics (crude protein, crude fat, crude ash) were not significantly different between control and grape seed oil treatment groups. Moisture content of grape seed oil treatment groups (GSO 30% and 40%) was significantly lower than that of controls (p<0.05). There was a not clear difference in pH between control and grape seed oil treatment groups. In the 21 d of storage, pH values of all treatments were significantly higher than those of other storage days. Meat color $(CIEL^*\;and\;b^*)$ of grape seed oil treatment group (GSO 40%) was significantly higher than that of control. Whereas meat color a value of GSO 40% treatment was significantly lower than that of control. It was not clearly changed as storage time increased. There was no significant difference in texture between control and grape seed oil treatment groups, and appeared to be unaffected by storage length. Based on these findings, we conclude that the chemical composition and texture characteristics of manufactured pressed ham were not affected by grape seed oil addition. These results also indicate that high-quality pressed ham can be manufactured with increased polyunsaturated fatty acid content.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.11
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• pp.1715-1718
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• 2010

The oxidative stability of grape seed oils (GSOs) prepared from grape seeds roasted at different temperatures (100, 150 and $200^{\circ}C$ for 1 hr) was evaluated and compared with that of GSO from unroasted grape seed. Stability of the GSOs stored in air at $50^{\circ}C$ up to 40 days was assessed by acid value (AV) and peroxide value (PV). Simultaneously, the cont ents of tocopherols and tocotrienols and color changes were monitored up to 40 days. During the storage period, the PV of the unroasted GSO increased from 1.95 to 90.72 meq/kg. On the other hand, the PV for GSOs roasted at 100, 150 and $200^{\circ}C$ increased from 1.96, 2.03, 1.98 to 76.09, 71.72, 49.38 meq/kg, respectively. AV is in conformity with PV. Color development of GSOs increased as roasting temperature increased. The contents of tocopherols and tocotrienols in GSOs increased as roasting temperature increased from 100 to $200^{\circ}C$. The contents of tocopherols and tocotrienols gradually decreased along with the storage period. These results suggest that roasting treatment prolongs the oxidative stability of GSOs.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.96-99
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• 2004

The objective of this study is to assess attenuation correction algorithms utilized in a multipurpose whole-body GSO PET scanner. Four different types of phantoms were tested using different types of attenuation correction techniques. FOV (Field of View) of 256mm was used for brain PET imaging. For compensating attenuation, transmission data of a $^{137}$Cs point source were acquired after the F-18 emission source was infused to the phantoms. Scatter correction were peformed. Reconstructed images of the phantoms were assessed. In addition, reconstructed images of a normal subject were compared and assessed by nuclear medicine physicians. As a result, decreased intensity at the central portion of the attenuation map with cylindrical phantom was noticed during use of the measured attenuation correction. On the other hand, segmentation or remapping attenuation correction provided uniform phantom image. the images reconstructed from the clinical brain data explained the attenuation of a skull, at though reconstructed images of the phantoms couldn't explain it. in conclusion, the complicated and improved attenuation correction methods were required to obtain the better accuracy of the quantitative brain PET images. Our study will be useful in improving quantitative brain PET imaging modalities with attenuation correction of $^{137}$Cs transmission source.

• Korean Journal of Food Science and Technology
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• v.26 no.2
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• pp.178-183
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• 1994

The fresh perilla seed and tile one-year stored perilla seed were solvent extracted for their oil. On the other hand, the fresh seed and the stored seed were germinated in the dark at $25{\sim}28^{\circ}C\;for\;2{sim}3$ days and then solvent extracted. The above four kinds of perilla oil, that is, the oil from the nongerminated and fresh seed(NFO), the oil from the nongerminated and one-year stored seed (NSO), the oil from the germinated and fresh seed(GFO), and the oil from the germinated and one-year stored seed(GSO) were analyzed with regards to the chemical composition, and the effects of germination of the seed on the oxidative stability of perilla oil were studied. The iodine value and the saponification value were similar in all the perilla oils, but the acid value was increased by germination of the seed. The contents of free fatty acid and diacylglycerol were increased by germination of the seed, while the content of triacylglycerol was decreased. Of the polar lipid components, the content of phosphatidyl ethanolamine was greatly increased by germination of the seed. The contents of total tocopherol of perilla oil from the fresh seed and the one-year stored seed were 494 ppm and 439 ppm, respectively, and by germination of the seed increased to 560 ppm in GFO and 515 ppm in GSO, respectively. Especially a great change in the content of ${\gamma}-tocopherol$ was observed. The oxidative stability of perilla oil was increased by germination of the seed and the increase was distinct in the case of the one-year stored seed compared with that in the case of the fresh seed.