• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.6
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• pp.2450-2469
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• 2018

In this paper, we develop a spatiotemporal model to analysis of cellular user in underlay D2D communication by using stochastic geometry and queuing theory. Firstly, by exploring stochastic geometry to model the user locations, we derive the probability that the SINR of cellular user in a predefined interval, which constrains the corresponding transmission rate of cellular user. Secondly, in contrast to the previous studies with full traffic models, we employ queueing theory to evaluate the performance parameters of dynamic traffic model and formulate the cellular user transmission mechanism as a M/G/1 queuing model. In the derivation, Embedded Markov chain is introduced to depict the stationary distribution of cellular user queue status. Thirdly, the expressions of performance metrics in terms of mean queue length, mean throughput, mean delay and mean dropping probability are obtained, respectively. Simulation results show the validity and rationality of the theoretical analysis under different channel conditions.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.5
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• pp.2258-2276
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• 2019

Resource sharing is one of the main goals achieved by network virtualization technology to enhance network resource utilization and enable resource customization. Though resource sharing can improve network efficiency by accommodating various users in a network, limited infrastructure capacity is still a challenge to ultra-low latency service operators. In this paper, we propose an inter-slice resource borrowing schema based on the device-to-device (D2D) potentiality especially for ultra-low latency transmission in cellular networks. An extended and modified Kuhn-Munkres bipartite matching algorithm is developed to optimally achieve inter-slice resource borrowing. Simulation results show that, proper D2D user matching can be achieved, satisfying ultra-low latency (ULL) users' quality of service (QoS) requirements and resource utilization in various scenarios.

• Proceedings of the Korea Crystallographic Association Conference
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• 2003.05a
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• pp.12-12
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• 2003

초전도 선재로의 응용을 위하여 Pulsed laser deposition(PLD)법으로 고온 초전도 체 YBa₂Cu₃O/sub 7-δ/(YBCO) coated conductor를 제조하였다. coated conductor는 금속기판/완충층/초전도층의 구조를 이루고 있는데 완충층은 금속 기판의 집합조직을 초전도층까지 전달하는 역할과 금속기판의 금속이 초전도층으로 확산되어 초전도층의 전기적 특성을 열화시키는 것을 막아주는 확산장벽으로의 역할 등을 수행한다. 완충층의 박막 성장이 제대로 이루어지지 않으면 우수한 초전도 특성을 가지는 초전도층을 얻을 수 없다. 완충층은 금속기판과의 lattice match, thermal match등이 요구되고, 화학적으로 금속기판 및 초전도층과 반응하지 않아야 하며, 긍속기판의 산화없이 epitaxial하게 박막증착이 이루어질 수 있는 재료이어야 한다. 이러한 조건을 만족하는 YBCO, CeO₂, YSZ 등이 주로 사용되고 있다. 전기연구원에서 YBCO coated conductor 선재를 제조하기 위하여 사용하고 있는 다층 박막의 구조는 YBCO/CeO₂/YSZ/CeO₂/Ni(002)과 YBCO/CeO₂/YSZ/Y₂O₃/Ni(002)이며, 최적의 증착조건을 찾기 위하여 성장시 챔버의 산소분압, 완충층의 두께, 기판 온도 등을 변화시켰다. 증착된 완충층 및 초전도층의 집합 조직은 D8-Discover with GADDS(General Area Detector Diffraction System)로 XRD분석을 했고, 미세구조는 SEM으로 관찰하였으며 4단자법을 이용하여 초전도 특성을 측정하였다.

• Journal of the Korean Vacuum Society
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• v.20 no.2
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• pp.141-145
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• 2011

ZnO:Al thin films were deposited by RF magnetron sputtering with various base pressure, and their structural, optical, and electrical properties were studied. The influence of the base pressure on the ZnO:Al thin film was confirmed and a high-quality thin film was obtained by controlling the base pressure. In all Al-doped ZnO thin films, the preferred orientation of (002) plane was observed and light transmittance in visible region (400 nm~800 nm) had above 85%. With decreasing of base pressure, crystallinity, resistivity, and figure of merit were improved. The improvement of resistivity with base pressure was attributed to the change of grain size.

• Journal of Sensor Science and Technology
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• v.5 no.6
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• pp.68-73
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• 1996

ZnO thin films were prepared on glass and (012) sapphire substrates by rf magnetron sputtering. Polycrysralline ZnO films with a (002) orientation were obtained on glass substrates. (110) ZnO films were epitaxially grown on the (012) sapphire substrates. Surface acoustic wave properties were also measured for propagating along the c axis of ZnO film on the glass and sapphire substrates. The phase velocities ($V_{p}$) on glass and sapphire substrate at center frequency were 2680 m/sec and 5980 m/sec and the effective coupling coefficient ($k^{2}$) on the 0th mode were 0.98 % and 1.43 %, respectively.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.3
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• pp.214-219
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• 2017

Coal workers' pneumoconiosis (CWP) and chronic obstructive pulmonary disease (COPD) are characterized as chronic inflammation of the lung in miners exposed to coal mine dust. The aim of the present study was to compare the levels of serum lactate dehydrogenase (LD) and C-reactive protein (CRP) as the inflammatory indices between subjects with CWP and those with CWP and COPD (CWP+COPD), among a total of 97 subjects (27 control, 40 CWP, and 30 CWP+COPD patients). The mean levels of serum LD (165.7 vs 184.6 U/L, p=0.016) and CRP (0.08 vs 0.15 mg/dL, p=0.002) in subjects with CWP were higher than those of in subjects without CWP. The mean level of serum CRP (0.10 vs 0.19 mg/dL, p=0.008) in subjects with COPD was higher than that in subjects without COPD. In an analysis of covariance adjusted by age, the mean level of serum CRP showed statistical significance among the study groups, control, CWP, and CWP+COPD (0.07 vs 0.13 vs 0.19 mg/dL, p=0.005); the mean level of serum CRP in the CWP+COPD group was significantly higher than that of the control group (p=0.001). The results suggest that a high level of CRP in the serum may be associated with CWP and COPD in retired coal miners.

• Food Science of Animal Resources
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• v.33 no.5
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• pp.617-625
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• 2013

The present study was carried out to assess dietary exposure and risk for the infant population by lead (Pb), cadmium (Cd), and arsenic (As) exposure through modified milk powder and formulas. Analysis of heavy metals was performed using a microwave device and inductively coupled plasma-mass spectrometry, the method for which was fully validated. Various samples (n=204), including modified milk powder, modified milk, follow-up modified milk powder, infant formula and follow- up formula, were collected from retail outlets and markets across Korea. The mean contents of heavy metals were Pb 0.0004 (modified milk)-0.010 (infant formula) mg/kg, Cd 0.002 (modified milk)-0.007 (follow-up formula) mg/kg, and As 0.004(modified milk)-0.040 (infant formula) mg/kg, respectively. For risk assessment, daily intakes of heavy metals through maximum intake of modified milk powder and formulas were calculated and compared with reference doses established by JECFA and WHO. The dietary exposures of heavy metals were $0.78-1.04{\mu}g$ Pb/d, $0.65-0.87{\mu}g$ Cd/d, and $2.25-3.00{\mu}g$ As/d, corresponding to 2.0-4.5%, 7.1-16.0%, and 0.4-0.9% of reference doses, respectively. Therefore, the level of overall dietary exposure to heavy metals for Korean infant through food intake was below 20% of the reference dose, indicating a low risk to infant consumers.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.4 s.119
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• pp.398-407
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• 2007

In this paper we proposed the tag antenna with a low performance distortion from an attached surface material using the asymmetric dual-arm dipole antenna(ADDA) structure. The tag is designed to exhibit low performance changes when the tag is attached on a target object(the medical litter receptacle, ${\varepsilon}_r=1.7,\;tan\;{\delta}=0.002$). Detail design parameters for the proposed antenna are optimized to maintain a good readable range in free-space as well as on a target object. The size of the optimized antenna is $100\;mm{\times}50\;mm$. The antenna shows the matching bandwidth($S_{11}$< -10 dB) of 3.7 % and the radiation efficiency of 80 % at the operating frequency. Finally we confirmed the readable range of the tag antenna by measurement and it shows about 5.3 m in free space and 5.5 m on the target object.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.16 no.2
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• pp.116-122
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• 2013

Purpose: Preterm infants on parenteral nutrition are at a relatively high risk for hypertriglyceridemia because they have immature lipoprotein lipase activity. The purpose of this study was to analyze the clinical factors affecting lipid metabolism in preterm infants receiving parenteral nutrition and to evaluate the influence of intravenous heparin on serum triglycerides to determine the adequate heparin dose to prevent hypertriglyceridemia in preterm infants. Methods: A single-center retrospective review was conducted among preterm infants receiving parenteral nutrition between January 2006 and February 2011. In 75 patients, 110 determinations were performed within 28 days postnatal age. Demographic and clinical data, including laboratory parameters, the dose and the duration of lipid administration, and the amount of intravenous heparin, were analyzed. Results: Serum triglycerides were higher in the small for gestational age (SGA) infants than in the appropriate for gestational age infants ($185.5{\pm}134.9$ mg/dL vs. $126.9{\pm}101.9$ mg/dL, p=0.019). Birth weight, gestational age, and body weight were negatively correlated with serum triglyceride level (r=-0.289, p=0.002; r=-0.208, p=0.029; r=-0.287, p=0.002, respectively). The serum triglyceride level was statistically lower in preterm infants receiving 1 U/mL of heparin than in those receiving 0.5 U/mL heparin or no heparin. Conclusion: Preterm infants receiving parenteral nutrition, particularly SGA and extremely low birth weight infants, tend to have hypertriglyceridemia. Thus, administration of 1 U/mL of heparin rather than 0.5 U/mL or none may be helpful to prevent hypertriglyceridemia in preterm infants.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5215-5220
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• 2013

Recent construction in the field of 3D aversion is increasing interest in automation. This study is results about survey of the coastal landfill using automatic VRS-GPS surveying system. GPS is made with GRXI and SHC250 controller. Automatic surveying system is composed of DPS module, geomagnetism sensor, bluetooth, gimbals, IMU, etc and enables an automatic driving via entered into a route of position. The developed auto surveying system has installed the front and camera for vertical axis and can grasp situation of surveying with smartphone in real time. The comparative result between surveyed result with repetition method auto VRS-GPS surveying system observed surveyed result with VRS-RTK has shown that average error of x-axis is 0.009m, average error of y-axis, 0.010m and average error of height, 0.002m. This possibility was confirmed that field application.