• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.259-266
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• 2013

Since the wireless communications have a limited transmission, the devices just around a master node can exchange data. Though Bluetooth and Zigbee support ad hoc, they are not appropriate for real-time voice communications. In this paper, we present a TDMA-based relay protocol for several users to communicate simultaneously. The proposed protocol can relay data or voice to other nodes in real-time by the multi-hop transmission method using TDMA. And the proposed protocol improves the network performance by allocating different frequencies to the slaves depending on the routing path scheduled by the routing table. NS-2 simulation shows that the performance of the proposed protocol is good in terms of the transmission delay and pecket loss probability in the real-time voice transmission.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.8
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• pp.3551-3567
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• 2016

The Low Earth Orbit satellite network has the unique characteristics of the non-uniform and time-variant traffic load distribution, which often causes severe link congestion and thus results in poor performance for delay-sensitive flows, especially when the network is heavily loaded. To solve this problem, a novel adaptive routing algorithm, referred to as the delay-oriented adaptive routing algorithm (DOAR), is proposed. Different from current reactive schemes, DOAR employs Destination-Sequenced Distance-Vector (DSDV) routing algorithm, which is a proactive scheme. DSDV is extended to a multipath QoS version to generate alternative routes in active with real-time delay metric, which leads to two significant advantages. First, the flows can be timely and accurately detected for route adjustment. Second, it enables fast, flexible, and optimized QoS matching between the alternative routes and adjustment requiring flows and meanwhile avoids delay growth caused by increased hop number and diffused congestion range. In addition, a retrospective route adjustment requesting scheme is designed in DOAR to enlarge the alternative routes set in the severe congestion state in a large area. Simulation result suggests that DOAR performs better than typical adaptive routing algorithms in terms of the throughput and the delay in a variety of traffic intensity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.34-41
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• 2017

Wireless mesh networks contain multi-hop routing protocols between wireless nodes and are connected to the Internet through a gateway. These networks perform a role as a backbone and are scalable for main applications. We propose the design of QoS supporting mechanisms for wireless mesh networks using software defined networking. Our proposed scheme is cost-effective and features adaptive QoS mechanisms for wireless router's resource constraints. The QoS mechanisms use software defined networking technology with Openflow protocol based on diffserv and intserv models with MPLS mechanism and RSVP respectively. A performance evaluation model is suggested to verify the validity of the proposed scheme using several QoSmetrics of the wireless mesh networks.

• Journal of Microbiology and Biotechnology
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• v.27 no.10
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• pp.1885-1891
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• 2017

In this study, we evaluated the inhibitory effect of a rice bran mixture extract (RBE) on Brucella abortus pathogenesis in professional (RAW 264.7) and nonprofessional (HeLa) phagocytes. We fermented the rice bran mixture and then extracted it with 50% ethanol followed by gas chromatography-mass spectrometry to identify the components in RBE. Our results clearly showed that RBE caused a significant reduction in the adherence of B. abortus in both cell lines. Furthermore, analysis of phagocytic signaling proteins by western blot assay revealed that RBE pretreatment resulted in inhibition of phosphorylation of JNK, ERK, and p38, leading to decline of internalization compared with the controls. Additionally, the intensity of F-actin observed by fluorescence microscopy and FACS was remarkably reduced in RBE-pretreated cells compared with control cells. However, the intracellular replication of B. abortus within phagocytes was not affected by RBE. Taken together, these findings suggest that the phagocytic receptor blocking and suppressive effects of RBE on the MAPK-linked phagocytic signaling pathway could negatively affect the invasion of B. abortus into phagocytes.

• Journal of Microbiology and Biotechnology
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• v.27 no.10
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• pp.1837-1843
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• 2017

Knowledge of avian host responses to brucellosis is critical to understanding how birds resist this infection; however, this mechanism is not well established. On the other hand, temperature has a major involvement in the physiology of living organisms, and cell death induced by heat is attributed to protein denaturation. This study demonstrates the direct bactericidal effect of a high temperature ($41^{\circ}C$) on Brucella abortus that resulted in the gradual reduction of intracellular bacteria and inhibited bacterial growth within avian macrophage HD11 in an increasing period of time. On the other hand, this study also revealed that high temperature does not affect the rate of bacterial uptake, as confirmed by the bacterial adherence assay. No significant difference was observed in the expression of target genes between infected and uninfected cells for both temperatures. This study suggests the susceptibility of B. abortus to bacterial death under a high temperature with an increased period of incubation, leading to suppression of bacterial growth.

• Journal of Digital Contents Society
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• v.18 no.6
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• pp.1025-1032
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• 2017

Recently the domestic popular song market has been growing mainly in digital sound sources. As a result of analyzing the top 100 music charts from 2012 to 2016 through digital sound sources and musical scores, the average annual BPM has fallen by 11.26 over five years. Every year, The style of music has diversified every year, and the proportion of Hip-hop has doubled from 8.5% in 2012 to 17.8% in 2015. Dance music and ballads have a high preference rate, but the relationship is inversely proportional. Singer composition was inversely proportional to the ratio of female solo to male group. Especially, the relationship between BPM and the Major/Minor key is that 81.42% for slow tempo songs is Major key and 53.85% for fast tempo songs is minor key. In the case of TV drama OST, the solo singer 's music was preferred, the music style was 80% pop and 20% ballad.

• Korean Journal of Applied Biomechanics
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• v.25 no.1
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• pp.39-47
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• 2015

Objective : The purpose of this study was to investigate the velocity conversion coefficient and invariance for the optimal phase ratio on the performance of the women's triple jump. Methods : Three-dimensional kinematic data were obtained from the three finalists of the women's triple jumper competition at the 2011 Daegu IAAF World Championships. Computer simulations were performed using the biomechanical model of the triple jump to optimize the phase ratio for the longest actual distance for all athletes with altered velocity conversion coefficients. Results : Top elite triple jumpers showed better technical consistency at the phase ratio. Also, no consistent relationship was observed between the loss in horizontal velocity and the gain in vertical velocity across supporting the three phase. In addition, regardless of the magnitude A1, all athletes were optimized with jump-dominated technique. Finally, as the magnitude of A1 increased, the athletes showed better performance. The obtained overall distance jumped showed the longest actual distance when the optimal phase ratio was transferred from hop-dominated to jump-dominated(the step ratio was 30%~31%), and when the optimal phase ratio was transferred from balanced to jump-dominated(the step ratio was 27%~29%). Conclusion : Future studies need to be conducted in order to explore the active landing motion and the inclination angle of the body with the velocity conversion coefficient simultaneously at each supporting phase.

• Biomolecules & Therapeutics
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• v.17 no.4
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• pp.422-429
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• 2009

Invasion and metastasis is the main cause of cancer mortality. Angiogenesis is a prerequisite for the tumor growth and metastasis. Matrix metalloproteinases (MMPs) are the key enzymes playing in the invasive growth and metastasis of cancer as well as angiogenesis. Xanthohumol, a prenylated chalcone of the Hop plant (Humulus lupulus L), has been reported to suppress cancer invasion and angiogenesis. In the present study, we investigated the antiinvasive effects of xanthohumol (1) and its synthetic derivatives, 4'-O-methylxanthohumol SEM ether (2), xanthohumol C (3), and xanthohumol C MOM ether (4) in relation to MMP expression in HT-1080 human fibrosarcoma cells. The compound 1 and its derivative, 3 and 4, significantly inhibited serum-induced HT-1080 cell invasion, and 12-O-tetradecanoylphorbol-13-acetate (TPA)-enhanced activity and expression level of MMP-2 and MMP-9 in a concentration-dependant manner. In addition, they inhibited TPA-enhanced expression of MT1-MMP with relatively weak inhibition in tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 level. The compound 1 significantly decreased the cell viability, whereas the derivatives, 2 and 3 showed no cytotoxicity, and compound 4 showed slight cytotoxicity in the cells. Furthermore, in a chick chorioallantoic membrane (CAM) assay, the derivatives 3 and 4 dose-dependently suppressed vascular endothelial growth factor (VEGF)-induced angiogenesis, which is similar to that of compound 1. Taken together, the results indicate that compounds 3 and 4 may be valuable anti-angiogenic agents in the treatment of chronic diseases such as cancer and inflammation working through suppression of MMP-2 and MMP-9.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.4 s.346
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• pp.13-21
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• 2006

An mobile ad hoc network(MANET) is a collection of wireless computers (nodes), communicating among themselves over multi-hop paths, without the help of any infrastructure such as base stations or access points. Prior research in MANET has generally studied the routing problem in a non-adversarial setting, assuming a trusted environment. In this paper, we design and evaluate the Secure Zone Routing Protocol(T-ZRP), a secure ad hoc network routing protocol is based on the design of the hash chain. In order to support use with nodes of limited CPU processing capability, and to guard against Denial-of-Service attacks in which an attacker attempts to cause other nodes to consume excess network bandwidth or processing time, we use efficient one-way hash functions and don't use asymmetric cryptographic operations in the protocol. Proposed algorithm can safely send to data through authentication mechanism and integrity about routing establishment.

• Journal of Korean Academy of Nursing
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• v.37 no.6
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• pp.902-913
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• 2007

Purpose: The purpose of this study was to identify the effects of a physical activity-behavior modification combined intervention(PABM-intervention) on metabolic risk factors in overweight and obese elementary school children. Methods: Thirty-two participants ($BMI\geq85$ percentile or relative $obesity\geq10$) were allocated to the PABM-intervention group and behavior modification only intervention group. The PABM -intervention was composed of exercise intervention consisting of 50 minutes of physical activity(Hip-hop dance & gym-based exercises) twice a week and the behavior modification intervention consisted of 50 minutes of instruction for modifying lifestyle habits(diet & exercise) once a week. Effectiveness of intervention was based on waist circumference, BP, HDL-cholesterol, TG, and fasting glucose before and after the intervention. Results: The proportion of subjects with 1, 2, 3 or more metabolic risk factors were 28.1, 43.8, and 15.6%, respectively. After the 8-week intervention, waist circumference, systolic BP, diastolic BP, and HDL-cholesterol changed significantly(p<.01) in the PABM group. Conclusion: This provides evidence that a PABM-intervention is effective in changing metabolic risk factors such as waist circumference, systolic BP, diastolic BP, and HDL-cholesterol in overweight and obese elementary school children.