• KIPS Transactions on Software and Data Engineering
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• v.6 no.9
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• pp.429-436
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• 2017

Unmanned Aerial Vehicles (UAV) that are piloted without human pilots can be commanded remotely via frequencies or perform pre-inputted missions. UAVs have been mainly used for military purposes, but due to the development of ICT technology, they are now widely used in the private sector. Teal Group's 2014 World UAV Forecast predicts that the UAV market will grow by 10% annually over the next decade, reaching $ 12.5 billion by 2023. However, because UAVs are primarily remotely controlled, if a malicious user accesses a remotely controlled UAV, it could seriously infringe privacy and cause financial loss or even loss of life. To solve this problem, a secure channel must be established through mutual authentication between the UAV and the control center. However, existing security techniques require a lot of computing resources and power, and because communication distances, infrastructure, and data flow are different from UAV networks, it is unsuitable for application in UAV environments. To resolve this problem, the study presents a lightweight UAV authentication method based on Physical Unclonable Functions (PUFs) that requires less computing resources in the ground Control and Non-Payload Communication (CNPC) environment, where recently, technology standardization is actively under progress.

• Journal of Ginseng Research
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• v.42 no.2
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• pp.165-174
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• 2018

Background: Extended endoplasmic reticulum (ER) stress may initiate apoptotic pathways in cancer cells, and ER stress has been reported to possibly increase tumor death in cancer therapy. We previously reported that caspase-8 played an important role in compound K-induced apoptosis via activation of caspase-3 directly or indirectly through Bid cleavage, cytochrome c release, and caspase-9 activation in HL-60 human leukemia cells. The mechanisms leading to apoptosis in A549 and SK-MES-1 human lung cancer cells and the role of ER stress have not yet been understood. Methods: The apoptotic effects of compound K were analyzed using flow cytometry, and the changes in protein levels were determined using Western blot analysis. The intracellular calcium levels were monitored by staining with Fura-2/AM and Fluo-3/AM. Results: Compound K-induced ER stress was confirmed through increased phosphorylation of $eIF2{\alpha}$ and protein levels of GRP78/BiP, XBP-1S, and $IRE1{\alpha}$ in human lung cancer cells. Moreover, compound-K led to the accumulation of intracellular calcium and an increase in m-calpain activities that were both significantly inhibited by pretreatment either with BAPTA-AM (an intracellular $Ca^{2+}$ chelator) or dantrolene (an RyR channel antagonist). These results were correlated with the outcome that compound K induced ER stress-related apoptosis through caspase-12, as z-ATAD-fmk (a specific inhibitor of caspase-12) partially ameliorated this effect. Interestingly, 4-PBA (ER stress inhibitor) dramatically improved the compound K-induced apoptosis. Conclusion: Cell survival and intracellular $Ca^{2+}$ homeostasis during ER stress in human lung cancer cells are important factors in the induction of the compound K-induced apoptotic pathway.

• Journal of Korea Water Resources Association
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• v.43 no.9
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• pp.789-799
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• 2010

The objective of this study is to suggest an approach for estimating probability rainfall using climate scenario data based GCM and to analyze changes of flood characteristics like probability rainfall, flood quantile and flood water level under climate change. The study area is Namhan river basin. Probability rainfalls which is taken 1440 minutes duration and 100-year frequency are estimated by using IPCC SRES A2 climate change scenario for each time period (S0: 1971~2000; S1: 2011~2040; S2: 2041~2070; S3: 2071~2100). Flood quantiles are estimated for 17 subbasins and flood water level is analyzed in the main channel from the downstream of Chungju dam to the upstream of Paldang dam. Probability rainfalls, peak flow from flood quantile and water depth from flood water level have increase rate in the range of 13.0~15.1 % based S0 (142.1 mm), 29.1~33.5% based S0 ($20,708\;m^3/s$), 12.6~13.6% in each S1, S2 and S3 period, respectively.

• Transactions of the KSME C: Technology and Education
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• v.3 no.3
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• pp.217-223
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• 2015

The patterning of microbead in microfluidics channel is a practical technique for application in bio and medical areas. An approach is described for a direct patterning of magnetically active microbeads in microfluidic devices without inner structure. Local magnet arrangements - flat arrangement and stack arrangement - contacting same poles or opposite poles of magnet were utilized for generating trapping magnetic fields. The arrangement of magnets contacting same poles generated isolated patterns by repelling of magnetic field. The flat arrangement of vertically reverse magnet arrays shaped trapping patterns repelling magnetic field line between same poles. Spatially, the stack compositions of magnet arrangements allow diverse isolated trapped patterns of magnetic particles. Trapped magnetic particles in fluidic channels were stable on the $18m{\ell}/hr$ flow conditions and magnetic force of 1.08 mT in the all experiments. This experimental study suggests the simple and versatile methods to pattern magnetic particles, and has potential of wide application to bio and medical area.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.5
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• pp.38-48
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• 2007

In ubiquitous environment, sensor networks that sense and transmit surrounding data without human intervention will become more important. If sensors are installed for detecting vehicles and measuring their speed in the road and that real-time information is given to drivers, it will be very effective for enhancing safety and controlling traffic in the road. In this paper, we proposed a new reliable and real-time sensor MAC protocol between AP and sensor nodes in order to provide real-time traffic flow information based on ubiquitous sensor networks. The proposed MAC allocates one TDMA slot for each sensor node on the IEEE 802.15.4 based channel structure, introduces relayed communication for distant sensors, and adopts a frame structure that supports retransmission for the case of errors. In addition, the proposed MAC synchronizes with AP by using beacon and adopts a hybrid tracking mode that supports economic power consumption according to various traffic situations, We implemented a simulator for the proposed MAC by using sim++ and evaluated various performances. The simulation results show that the proposed MAC reduces the power consumption and reveals excellent performance in real-time application systems.

• Explosives and Blasting
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• v.21 no.3
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• pp.23-35
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• 2003

An analytical diffusion model for flood routing with backwater effects and lateral flows is developed. The basic diffusion equation is linearized about an average depth of (H + h), and is solved using the boundary conditons which take into account the effects of backwater and lateral flows. Scouring phenomenon around pier which affects on the support function of pier and the stabilization if river bed is a complex problem depending on flow properties and river bed state as well as pier geometry. therefore, there is no uniting theory at present which would enable the designer to estimate, with confidence, the depth of scour at bridge piers. The various methods used in erosion control are collectively called upstream engineering, HEC-RAS Model, underwater blasting. They consist of reforestation, check-dam construction, planting of burned-over areas, contour plowing and regulation of crop and grazing practices. Also included are measures for proper treatment of high embankments and cuts and stabilization of streambanks by planting or by revetment construction. One phase of reforestation that may be applied near a reservoir is planting of vegetation screens. Such screens, planted on the flats adjacent to the normal stream channel at the head of a reservoir, reduce the velocity of silt-laden storm inflows that inundate these areas. This stilling action causes extensive deposition to occur before the silt reaches the main cavity of the reservoir.

• Ecology and Resilient Infrastructure
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• v.7 no.1
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• pp.1-14
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• 2020

In fluvial and riparian ecosystems, biogeomorphological research has considered the complex, multi-way relationships between biological and hydro-geomorphological components over a wide range of spatial and temporal scales. In this review, we discussed the scope and processes of fluvial biogeomorphology by explaining (1) the multi-lateral interactions between organisms and hydrogeomorphic conditions, (2) the relationships between biodiversity and habitat heterogeneity, and (3) the effects of disturbance on ecosystem patterns. Over time, an organism-landform complex along streams transitions in the sequences of geomorphic, pioneer, biogeomorphic, and ecological stages. Over space, water flow and sediment distributions interact with vegetation to modify channel topography. It is the habitat heterogeneity in streams that enhances riparian biodiversity. However, in the areas downstream of a dam, habitat types and conditions are substantially damaged and biodiversity should be reduced. In South Korea, riparian vegetation flourishes in general and, in particular, invasive species actively colonize in accordance with the changes in the fluvial conditions driven by local disturbances and global climate change. Therefore, the importance of understanding reciprocal relationships between living organisms and hydrogeomorphic conditions will ever increase in this era of rapid climate change and anthropogenic pressure. The fluvial biogeomorphic framework reviewed in this article will contribute to the ecological management and restoration of streams in Korea.

• Journal of Chest Surgery
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• v.33 no.6
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• pp.494-501
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• 2000

Background: Transmyocardial laser revascularization(TMLR) for revascularizing ischemic myocardium in patients was originally based on the assumption that laser channels remain their patency much longer. But recent studies show that laser channels did not remain open and that TMLR could achieve treatment benefits without long-term channel patency. The angiongencesis is currently thought to be induced by non-specific inflammatory response to mechanical tissue injury. This study is to evaluate hypothesis that various transmyocaridal mechanical revascularization(TMMR) may induce the angiogenic responses similar to that seen with TMLR, and transmyocaridal polymer stent revascularization(TMSR), the polymer stent in the myocardial tissue is hydrolyzed in 2 weeks, may enhance the non-specific inflammatory reaction resulting angiogenesis. Furthermore, polymer myocaridal stent channels remain long-term patency. Material and Method: Eight domestic pigs underwent ligation of the proximal circumflex artery, and 2 weeks later they were randomized to undergo transmycardial acupunctural revascularization (TMPR, Group I) of the left lateral wall with 18-G needle(n=2), to undergo transmyocardial (TMDR, Group II) with industrial 2mm steel drill(n=2), to undergo transmyocardial polymer stent revascularization (TMSR, Group III) after drilling the infarcted myocardium(n=2), the stent is poly(lactic acid-co-glycolic acid), which is self-degradated in the myocardium, and to a control group the ischemic zone was unterated(n=2). All the pigs were sacrificed after 4 weeks TMMR. Sections from the ischemic zone were submitted for vascular endothelial growth factor (VEGF) ELISA and histology. Result: There were makedly increase in the VEGF immunoassay in the ischemic zone of the TMMR group compared to the ischemic zone of the control group(control: each 30.85 and 43.15pg/mg protein, TMPR: each 44.14 and 68.61 pg/mg protein, TMDR: each 65.92 and 78.65 pg/mg protein, TMSR: each 177.39 and 168.87 pg/mg protein). TMSR channels caused greatest VEGF expression than channels made by other group and the polymer stent channels remained vacuole after 4 weeks. Conclusion: Transmyocardial polymer stent revascularization promoted the most angiogenci response by the VEGF immunoassay, although our study did not show the statistical significancy. The channels remained but the flow patency was not verified. Transmyocardial polymer stent revascularization (TMSR) is desirable in future experimental trials and in view of the significant cost implications comparable to that of laser.

• Journal of the Korean Geographical Society
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• v.40 no.4 s.109
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• pp.416-427
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• 2005

This paper aims to investigate morphological changes of deltaic barrier islands in the Nakdong Estuary and especially their spatial variations after barrage construction. We analyzed shorelines, geometrical centroids, and areas to reveal the changes of barrier islands. Here, we suggest three interesting points from this study. First, each individual barrier island in the Nakdong estuary goes through a different stage of the geomorphic cycle. The frontal barrier islands such as Sinja-do and Doyo-deung grow because they are located in front of the gates of the barrage. Sediments in water out of the gates are moved to offshore and then reworked by coastal processes such as waves and tides. Second, on the contrary, Baekhap-deung located behind Doyo-deung now diminishes indicating that sediments mainly move to the frontal growing island. Third, there is no morphological change in several barrier islands far away from the main flow of the Nakdong river such as Jinwoo-do, Daema-deung, and Jangja-do. In conclusion, barrier islands in the Nakdong estuary show distinct spatial variations. As a barrier island is closer to the main channel or is in the frontal location, there happens a very dynamic change in the morphology of the island.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.4B
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• pp.383-391
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• 2011

In this study, an evaluation method was proposed to determine the restoration section in the riverine ecobelt project. The target river for this study is the Hongcheon river in Kangwon-do. The Hongcheon river of 96 km was divided longitudinally into subsections of 2 km. The analysis through map and aerial photograph as well as field surveys were performed in 48-sub-sections. The fragmentation items were classified into connectivity and ecological functionality. The connectivity fragmentation was also divided into two items: the area discontinuity of the land use and the line discontinuity of river bank and road. Also, the ecological functional fragmentation was evaluated by using the items of river channel, river bed, vegetation, and the obstruction of river flow. These items was modified from those in the previous literature. From map analyses and field surveys, the fragmentation score was kept with each items in 48 sub-sections of Hongcheon river. The fragmentation rate was made from the total score in each section. The results showed that sections from F1 to G2 was evaluated to have high rates of all connectivity and functionality fragmentation of 1st or 2nd rate. Other sections have high connectivity fragmentation of 2nd rate, but low functional fragmentation. Thus, these sections are evaluated to be excludible in restoration site. This study seems to make a contribution to evaluate the fragmented sections for the riverine ecobelt project.