• Journal of Satellite, Information and Communications
• /
• v.11 no.3
• /
• pp.32-36
• /
• 2016

In wireless communication systems, jamming attack is a critical threat. Especially, reactive jamming can jam when the sender and receiver are communicating, which can maximize the attack efficiency of jamming. In this paper, we use the property of multi-input multi-output (MIMO) technology to achieve jamming resilient orthogonal frequency-division multiplexing (OFDM) communications. In particular, we use MIMO interference cancellation to remove the jamming signals strategically. We first investigate the reactive jamming attack model and their impacts on the MIMO-OFDM systems. We then present an iterative channel estimation algorithm that exploits MIMO interference cancellation. Our simulations show various anti-jamming methods and demonstrate the efficiency of our proposed algorithm under the reactive jamming attack.

• Korean Journal of Medicinal Crop Science
• /
• v.15 no.5
• /
• pp.352-356
• /
• 2007

The present study was investigated the anti-oxidative effects of aloe vera ingestion on brain and kidney in aged rats by monitoring several oxidative-related parameters. Male specific pathogen-free Fischer 344 rats were randomly divided into four groups of five rat each: Group A was fed test chow without aloe supplementation; Group B was fed a diet containing a 1% freeze-dried aloe filet; Group C was fed a diet containing a 1% charcoal-processed, freeze-dried aloe filet; and Group D was fed a diet containing a charcoal-processed, freeze-dried, whole leaf aloe in drinking water. Analyses of tissues were done at 4 months and 16 months of age. Results showed that a long-term intake of aloe, regardless of the preparation used, enhanced antioxidant defenses against lipid peroxidation, as indicated by reduced phosphatidylcholine hydroperoxide levels in both brain and kidney. The additional benefit of aloe intake on the anti-oxidative action was evidenced by enhanced superoxide dismutase and catalase activity in all aloe-ingested groups. Another beneficial effect of aloe shown in this study, although not an anti-oxidative parameter, was its cholesterol-lowering effect as detected in brain and kidney with significant decreases at age16 months of aloe-fed rats. Based on these findings, we conclude that a long-term dietary aloe supplementation modulated the anti-oxidative defense systems and cholesterol level.

• Journal of Sericultural and Entomological Science
• /
• v.22 no.2
• /
• pp.8-12
• /
• 1981

Practical application of silkworm artificial diet is very desirable to save labour in sericultural industry as the problem of labour shortage is becoming serious in Korea. However, silkworms reared on the artificial diet are more susceptible to viruses than those reared on mulberry leaves because of the lower anti-viral activity of gut juice of silkworms grown on artificial diet compared with that of silkworms grown on mulberry leaves. In this study, authors investigated the varietal difference of silkworm larvae, Bombyx mori L., reared on artificial diet which contained 20 percent of dried mulberry powder, in the susceptibility to nuclear polyhedrosis virus (NPV). The results showed that there is no difference in susceptibility to NPV among tested varieties when high concentration of NPV was admitted to silkworm larvae, but varietal difference appeared in lower concentration admitted. Among 7 hybrids tested, Hansaeng 1${\times}$Hansaeng 2 was most resistant to NPV with an $LC_{50}$ of 2.7${\times}$10$\^$6/ and Jam 111${\times}$Jam 112 was also more resistant comparatively than other hybrids.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2012.10a
• /
• pp.128-130
• /
• 2012

One of the hot issues on GNSS might be that China declared to broadcast the signal of the new Global Navigation Satellite System called Beidou-Compass in December 2011. The multi-GNSS systems with the existing GPS and GLONASS consist of more than 100 GNSS satellites and transmit their signals in near future. Many benefits are expected in accuracy, availability, integrity and increasing anti-jam performance. In this presentation, we have mainly investigated the latest issue for multi- GNSS and discussed spectrum analysis as well as the accuracy improvement issue. The use of the modern weapon system based on satellite navigation information was also briefly investigated in warfare.

• Food Science of Animal Resources
• /
• v.35 no.4
• /
• pp.507-514
• /
• 2015

Deer velvet antler (DVA) is one of the most popular medicines in China. Numerous studies have demonstrated that velvet antler possess biological effects. However, data regarding its anti-migration activity on prostate cancer is scarce. In this study, we investigated the inhibitory effect of top DVA (T-DVA) on the expression of prostate-specific antigen (PSA) and migration-related genes in the human prostate cancer cell, LNCaP. The T-DVA down-regulated the expression of PSA. In addition, the Radius^TM assay revealed that T-DVA inhibited the migration behavior of prostate cancer cells. Furthermore, the expression of matrix metalloproteinase (MMP)-9 and vascular endothelial growth factor (VEGF) was also decreased with T-DVA. On the contrary, T-DVA increased the tissue inhibition of metallo-proteinase (TIMP)-1 and (TIMP)-2. Taken together, our findings indicate that the T-DVA possesses anti-migration activity on prostate cancer cells. This is the first study of DVA to report the anti-migration activity on prostate cancer.

• Food Science of Animal Resources
• /
• v.31 no.3
• /
• pp.349-355
• /
• 2011

Russian deer velvet antlers were divided into three parts and subjected to a extraction process using hot water at 100, 110, and $120^{\circ}C$ or an extraction with 70% ethanol. Each extract was analyzed for its biochemical components, including uronic acid, sulfated-glycosaminoglycans (sulfated-GAGs), and sialic acid, and the antioxidant and anti-acetylcholinesterase activities were investigated. Different levels of uronic acid and sulfated-GAGs were observed in the extracts according to the water temperature used for the extraction, and contents decreased with increasing extraction temperature. The upper layer of each extract showed high amounts of uronic acid and sulfated-GAGs, followed by the middle and base layers. Ethanol extraction was more effective for recovering uronic acid than sulfated-GAGs. Sialic acid content was the highest in the $110^{\circ}C$ extracts but was not observed in the ethanol extracts. Velvet antler extracts showed strong antioxidant activities against DPPH and hydrogen peroxide as well as strong reducing power in a dose-dependent manner. However, the antioxidant activities were different in each layer and according to the extraction method. Additionally, velvet antler extracts exhibited inhibitory activity against acetylcholinesterase, which is associated with Alzheimer's disease, in a dose-dependent manner. These results suggest that velvet antler extracts are useful as a functional food ingredient and/or a pharmaceutical.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.43 no.12
• /
• pp.1808-1816
• /
• 2014

The aim of this study was to evaluate the antioxidant activities and anti-inflammatory effects of water and ethanolic extracts from Allium hookeri roots and leaves. Antioxidant activities of Allium hookeri extracts were determined based on various radical scavenging activities using an ESR spectrophotometer, ferric reducing antioxidant power, 2,2'-azinobis-(3-ethybenzothiazoline-6-sulfonic acid) radical scavenging activity, and oxygen radical absorbance capacity assays. In addition, we investigated anti-inflammatory effects of Allium hookeri extract on lipopolysaccharide (LPS)-induced inflammation in RAW264.7 cells. We also explored the effects of extract from Allium hookeri root on suppression of pro-inflammatory mediators such as nitric oxide (NO) and pro-inflammatory cytokines such as IL-6 and TNF-${\alpha}$ against LPS-induced activation of RAW264.7 cells. Our results demonstrated superior antioxidant activity for leaf extract of Allium hookeri compared to extract from root of Allium hookeri. On the other hand, root extract of Allium hookeri showed better anti-inflammatory activity compared to leaf extract. Our study suggests that Allium hookeri extract exhibits strong antioxidant activity and anti-inflammatory effects and can be developed as a potential therapeutic candidate for diseases involving oxidative stress and inflammation.

• Journal of Microbiology and Biotechnology
• /
• v.26 no.1
• /
• pp.28-37
• /
• 2016

Numerous plants have been documented to contain phenolic compounds. Thymol is one among these phenolic compounds that possess a repertoire of pharmacological activities, including anti-inflammatory, anticancer, antioxidant, antibacterial, and antimicrobial effects. Despite of the plethora of affects elicited by thymol, its activity profile on gastric cancer cells is not explored. In this study, we discovered that thymol exerts anticancer effects by suppressing cell growth, inducing apoptosis, producing intracellular reactive oxygen species, depolarizing mitochondrial membrane potential, and activating the proapoptotic mitochondrial proteins Bax, cysteine aspartases (caspases), and poly ADP ribose polymerase in human gastric AGS cells. The outcomes of this study displayed that thymol, via an intrinsic mitochondrial pathway, was responsible for inducing apoptosis in gastric AGS cells. Hence, thymol might serve as a tentative agent in the future to treat cancer.

• Horticultural Science & Technology
• /
• v.31 no.4
• /
• pp.496-502
• /
• 2013

Grapes (Vitis vinifera) are one of the most important fruits worldwide and are eaten raw or after conversion to jelly, jam, juice and wine. Grape skins are a major source of resveratrol (3,5,4'-trihydroxystilbene), which has the ability to reduce blood sugar as well as anticancer, anti-inflammatory, and other beneficial cardiovascular effects. In this study, we investigated the increased accumulation of resveratrol in grape skin and leaves following ultrasonication treatment, which has been shown to induce resveratrol accumulation in several plants. Various ultrasonication treatment times and incubation periods were employed to identify the optimum conditions for the maximum accumulation of resveratrol. Treatment and further incubation led to increased resveratrol in both grape skins and leaves, with the highest increases of 7.7-fold and 1.9-fold occurring in response to 5 min ultrasonication treatment followed by 6 hour incubation and 15 min ultrasonication treatment followed by 3 hour incubation, respectively. The underlying mechanism for the increased amounts of resveratrol were studied by employing a semi-quantitative RT-PCR to monitor the expression levels of the resveratrol synthase (RS) gene in response to ultrasonication treatment. The RS gene increased the expression in response to ultrasonication treatment, suggesting that up-regulation of the RS gene by ultrasonication treatment triggers increased amounts of resveratrol. Taken together, these data indicate that this simple ultrasonication treatment of grapes can be an efficient post-harvest technology for increasing resveratrol in grape skins in addition to cleaning the fruits.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.5 no.2
• /
• pp.185-194
• /
• 2002

To extract relative ranges from LOS(line of sight) information, we propose a passive ranging filter which is suitable for anti-ship missiles in HOJ(home on jam) mode. The proposed filter is devised to cope with the case that a passive ranging filter may include a large initial range estimation error since modem jammers are capable of very long range jamming. In addition, under the assumption that the missile motion is dominant over the HOJ engagement situation, the engagement geometry is modeled by a second order system. A new passive ranging filter is proposed by constructing an extended Kalman filter(EKF) based on the model. And then a least square initial state error estimation algorithm is attached to the EKF. Simulation results show that the proposed filter has a good range estimation performance with small computational load.