• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.316-325
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• 2018

In this paper, to integrate distributed IT resources and manage human resource efficiently as purpose of cost reduction, infrastructure of wind turbine monitoring system have been designed and developed on the basis of SaaS cloud. This infrastructure hierarchize data according to related task and services. Softwares to monitor conditions via the infrastructure are also developed. Softwares are made up of DB design, field measurement, data transmission and monitoring programs. The infrastructure is able to monitor conditions from SCADA data and additional sensors. Total time delay from field measurement to monitoring is defined by modeling of step-wise time delay in condition monitoring algorithms. Since vibration data are acquired by measurements of high resolution, the delay is unavoidable and it is essential information for application of O&M program. Monitoring target is gearbox in wind turbine of MW-class and it is operating for 10 years, which means that accurate monitoring is essential for its efficient O&M in the future. The infrastructure is in operation to deal with the gearbox conditions with high resolution of 50 TB data capacity, annually.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.1
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• pp.18-26
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• 2016

The semiconductor industry is one of the key industries of Korea, which has continued growing at a steady annual growth rate. Important technology for the semiconductor industry is high integration of devices. This is to increase the memory capacity for unit area, of which key is photolithography. The photolithography refers to a technique for printing the shadow of light lit on the mask surface on to wafer, which is the most important process in a semiconductor manufacturing process. In this study, the width and step-height of wafers patterned through this process were measured to ensure uniformity. The widths and inter-plate heights of the specimens patterned using photolithography were measured using transmissive digital holography. A transmissive digital holographic interferometer was configured, and nine arbitrary points were set on the specimens as measured points. The measurement of each point was compared with the measurements performed using a commercial device called scanning electron microscope (SEM) and Alpha Step. Transmission digital holography requires a short measurement time, which is an advantage compared to other techniques. Furthermore, it uses magnification lenses, allowing the flexibility of changing between high and low magnifications. The test results confirmed that transmissive digital holography is a useful technique for measuring patterns printed using photolithography.

• Journal of IKEEE
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• v.26 no.3
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• pp.510-514
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• 2022

In this paper, we propose the development of high-sensitivity low-end radiation measuring sensor module. The proposed measurement sensor module is a scintillator + photomultiplier(SiPM) sensor optimization structure design, amplification and filter and control circuit design for sensor driver, control circuit design including short-distance communication, sensor mechanism design and manufacturing, and GUI development applied to prototypes consists of, etc. The scintillator + photomultiplier(SiPM) sensor optimization structure design is designed by checking the characteristics of the scintillator and the photomultiplier (SiPM) for the sensor structure design. Amplification, filter and control circuit design for sensor driver is designed to process fine scintillation signal generated by radiation with a scintillator using SiPM. Control circuit design including short-distance communication is designed to enable data transmission through MCU design to support short-range wireless communication function and wired communication support. The sensor mechanism design and manufacture is designed so that the glare generated by wrapping a reflective paper (mirroring) on the outside of the plastic scintillator is reflected to increase the efficiency in order to transmit the fine scintillation signal generated from the plastic scintillator to the photomultiplier(SiPM). The GUI development applied to the prototype expresses the date and time at the top according to each screen and allows the measurement unit and time, seconds, alarm level, communication status, battery capacity, etc. to be expressed. In order to evaluate the performance of the proposed system, the results of experiments conducted by an authorized testing institute showed that the radiation dose measurement range was 30 𝜇Sv/h ~ 10 mSv/h, so the results are the same as the highest level among products sold commercially at domestic and foreign. In addition, it was confirmed that the measurement uncertainty of ±7.4% was measured, and normal operation was performed under the international standard ±15%.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.2
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• pp.249-256
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• 2022

Various studies are being actively conducted to show that the real-time visualization technology that combines BIM (Building Information Modeling) and AR (Augmented Reality) helps to increase construction management decision-making and processing efficiency. However, when large-capacity BIM data is projected into AR, there are various limitations such as data transmission and connection problems and the image cut-off issue. To improve the high efficiency of visualizing, a mesh optimization algorithm based on the k-nearest neighbors (KNN) classification framework to reconstruct BIM data is proposed in place of existing mesh optimization methods that are complicated and cannot adequately handle meshes with numerous boundaries of the 3D models. In the proposed algorithm, our target BIM model is optimized with the Unity C# code based on triangle centroid concepts and classified using the KNN. As a result, the algorithm can check the number of mesh vertices and triangles before and after optimization of the entire model and each structure. In addition, it is able to optimize the mesh vertices of the original model by approximately 56 % and the triangles by about 42 %. Moreover, compared to the original model, the optimized model shows no visual differences in the model elements and information, meaning that high-performance visualization can be expected when using AR devices.

• Journal of Advanced Navigation Technology
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• v.21 no.6
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• pp.659-665
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• 2017

In this paper, a low complexity fast Fourier transform(FFT) processor is proposed for multiple input multiple output(MIMO) systems. The IEEE 802.11ac standard has been adopted along with the demand for a system capable of high channel capacity and Gbps transmission in order to utilize various multimedia services using a wireless LAN. The proposed scalable FFT processor can support the variable length of 64, 128, 256, and 512 for 8x8 antenna configuration as specified in IEEE 802.11ac standard with MIMO-OFDM scheme. By reducing the required number of non-trivial multipliers with mixed-radix(MR) and multipath delay commutator(MDC) architecture, the complexity of the proposed FFT processor was dramatically decreased. Implementation results show that the proposed FFT processor can reduced the logic gate count by 50%, compared with the radix-2 SDF FFT processor. Also, compared with the 8-channel MR-2/2/2/4/2/4/2 MDC processor and 8-channel MR-2/2/2/8/8 MDC processor, it is shown that the gate count is reduced by 18% and 17% respectively.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.4
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• pp.29-39
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• 2009

The need for radio spectrum is recently considered as a huge hurdle towards the rapid development of wireless networks. Large parts of the spectrum are allocated to licensed radio services in proprietary way. However, enormous success of the wireless services and technologies in the unlicensed bands has brought new ideas and innovations. In recent years cognitive radio has gained much attention for solving the spectrum scarcity problem. It changes the way spectrum is regulated so that more efficient spectrum utilization is possible. Multi-hop relay technology on the other hand has intensively been studied in the area of ad hoc and peer-to-peer networks. But in cellular network, only recently the integration of multi-hop capability is considered to enhance the performance significantly. Multi-hop relaying can extend the coverage of the cell to provide high data rate service to a greater distance and in the shadowed regions. Very few papers still exist that combine these methods to maximize the spectrum utilization. Thus we propose a network architecture combining these two technologies in a way to maximize the system throughput. We present the throughput capacity equations for the proposed system model considering various system parameters like utilization factor by the primary users and primary users' transmission radius and through extensive numerical simulations we analyze the significance of work.

• Journal of Bio-Environment Control
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• v.16 no.1
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• pp.72-77
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• 2007

This study was conducted to investigate the effect of functional cover film on oriental melon fruit quality under unheated plastic greenhouse cultivation in cold period. The 6 kind of films having different characteristics were covered at plastic greenhouses and oriental melon seedlings were cultivated at 2 regions of Seongju, respectively. The air-temperatures in plastic greenhouses of J-1 and J-2, having high infrared absorption rate, were about $2{\sim}5^{\circ}C$ higher than K-3. The contents of ${\beta}-carotene$ and sugar of fruit showed significant difference between functional and normal films. The sucrose, determining a sweetness during maturation, and soluble solids content of fruits cultivated in J-1, J-2, J-3, and K-1 were higher than those of K-2 and K-3. Ascorbic acid of fruits was highest in K-2 having low light transmission rate and thermo-keeping capacity. There was no significant difference in mineral content among all of cover films. These results indicated that the use of functional greenhouse covering films could improve fruit quality such as ${\beta}-carotene$ and sugar content of oriental melon.

• Applied Biological Chemistry
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• v.17 no.1
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• pp.1-30
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• 1974

Present study was undertaken to elucidate the relationship between uptake of nutrients and photosynthetic activities, and the translocation of several mineral nutrients in rice plants which were grown under different cultural conditions, utilizing radioactive tracer technique. Particular emphasis was placed on the analysis of patterns of nutrient uptake, the relationship between nutritional conditions and yield components. For this, rice plants grown on either low or high yielding fields at different growth stage were subjected to this study. The results are summarized as follows; 1. Varietal difference was observed in the uptake of potassium and phosphorus. Kusabue and Jinheung had good capacity but Paldal had rather poor capacity for the uptake of the both nutrients. 2. For rice plants, a high positive correlation was found between the oxidation of alpha plaus-naphthylamine by root and uptake of phosphorus. 3. Carbon assimilation rate repended on rice varieties. It was high in Noindo, Gutaenajuok #3 Suweon #82 and Jinheung but low in Taegujo, Kwanok, Yugu #132 etc. 4. Heavy application of nitrogen increased carbon assimilation in rice plants but this also depressed translocation of certain carbohydrates to ears. 5. Carbon assimilation wan greatly hampered in rice plants deficient in magnesium, phosphorus or potassium. 6. Total dry matter after ear formation stage, was much higher in rice plants grown in high yielding fields than those grown in low yielding fields. 7. Leaf area index(LAI) reached maximum at heading stage and decreased thereafter in high yielding fields. But in low yielding fields, it reached maximum before heading and sharply decreased thereafter due to early senescence of lower leaves. 8. In general, light transmission ratio (LTR) of leaves was higher in the early growth stage and lower in later stages. Higher ratio of LTR to leaf area index, was found in the rice grown in high yielding fields than those in low yielding fields. 9. Net photosynthetic activity decreased with the increase in leaf area index but was higher in high yielding fields than in low yielding fields. 10. After the ear formation stage, nitrogen, potassium and silicon as weil as $K_2O/N$ in straw were higher in high yielding fields than those in low yielding fields. 11. Nitrogen, phosphorus, potassium and magnesium taken up by rice plants in low yielding fields before heading stage were readily translocated to ears than those in high yielding fields. This suggests greater redistribution of nutrients in straw occurs due to lower uptake, in later growth stages, by rice plants grown in low yielding fields and hence results in early senescence due to nutrient deprivation. 12. In the high yielding fields nitrogen uptake by rice was slow but continuous throughout the life of the plants resulting in a large uptake even after heading. But, in low yielding fields the uptake was fast before heading and slow after heading. 13. A high positive correlation was found between the contents of nitrogen and potassium in the straw at heading stage and grain yield. Positive correlation was also found to hold between the contents of potassium, silicon, $K_2O/N$, $SiO_2/N$ in the straw at harvesting stage, and grain yield. 14. Carbon assimilation was greately hampered in rice plants deficient in magensium, phosphorus or potassium. 15. Uptake of nitrogen, phosphorus, potassium, silicon and manganese by rice was considerably higher in high yielding fields and reached maximum at ear formation stage. 16. In rice, a high positive correlation was discovered between total uptake of nitrogen, phosphorus, potassium, calcium, magnesium, silicon, manganese at harvesting stage and grain yield. 17. In rice, a high positive correlation was found between the total uptake of nitrogen, phosphorus, potassium, calcium, magnesium, silicon at harvesting stage, and number of spikelets per $3.3\;m^2$. In addition, a correlation was found between the total uptake of nitrogen and potassium and number of panicles per hill.

• Journal of the Korean Applied Science and Technology
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• v.38 no.6
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• pp.1687-1698
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• 2021

This study is to produce multiple layers of liposomes in a supercritical state and encapsulates active ingredients in order to stably encapsulate thermodynamically unstable active ingredients. In order to form a liposome in a supercritical state, a mixed surfactant development including vegetable-derived hydrogenated phosphatidyl choline and their delivative, hydrogenated sucrose distearate was synthesized as high purity. It describes a manufacturing method of injecting liquid carbon dioxide into a reactor to create a supercritical state and stirring to produce a giant liposome, and adding and loading genistein and quercetin. The HLB of the mixed lipid complex (SC-Lipid Complex) was 12.50, and multiple layers of liposome vesicles were formed even at very low concentrations. This surfactant had a specific odor with a pale yellow flake, the specific gravity was 0.972, and the acid value was 0.12, indicating that it was synthesized with high purity. As a result of the emulsifying capacity experiment using 20 wt% capric/capric triglyceride and triethylhexanoin using SC-Lipid Complex, it was found to have 96.2% emulsifying power. SC LIPOSOME GENISTEIN was confirmed that a multi-layer liposome vesicle was formed through a transmission electron microscope (Cryo-TEM) for the supercritical liposome encapsulated with genistein. The primary liposome particle size in which genistein was encapsulated was 253.9 nm, and the secondary capsule size was 18.2 ㎛. Using genistein as the standard substance, the encapsulation efficiency of supercritical liposomes was 99.5%, and general liposomes were found to have an efficiency of 93.6%. In addition, the antioxidant activity experiment in which quercetin was sealed was confirmed by the DPPH method, and it was found that the supercritical liposome significantly maintained excellent antioxidant activity. In this study, thermodynamically unstable raw materials were sealed into liposomes without organic solvents in a supercritical state. Based on these results, it is expected that it can be applied to various forms such as highly functional skincare cosmetics, makeup cosmetics, and scalp protection cosmetics.

• Korean Journal of Microbiology
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• v.52 no.2
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• pp.140-147
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• 2016

A process for manufacturing virally-safe porcine bone hydroxyapatite (HA) has been developed to serve as advanced xenograft material for dental applications. Porcine bone pieces were defatted with successive treatments of 30% hydrogen peroxide and 80% ethyl alcohol. The defatted porcine bone pieces were heat-treated in an oxygen atmosphere box furnace at $1,300^{\circ}C$ to remove collagen and organic compounds. The bone pieces were ground with a grinder and then the bone powder was sterilized by gamma irradiation. Morphological characteristics such as SEM (Scanning Electron Microscopy) and TEM (Transmission Electron Microscopy) images of the resulting porcine bone HA (THE Graft$^{(R)}$) were similar to those of a commercial bovine bone HA (Bio-Oss$^{(R)}$). In order to evaluate the efficacy of $1,300^{\circ}C$ heat treatment and gamma irradiation at a dose of 25 kGy for the inactivation of porcine viruses during the manufacture of porcine bone HA, a variety of experimental porcine viruses including transmissible gastroenteritis virus (TGEV), pseudorabies virus (PRV), porcine rotavirus (PRoV), and porcine parvovirus (PPV) were chosen. TGEV, PRV, PRoV, and PPV were completely inactivated to undetectable levels during the $1,300^{\circ}C$ heat treatment. The mean log reduction factors achieved were $${\geq_-}4.65$$ for TGEV, $${\geq_-}5.81$$ for PRV, $${\geq_-}6.28$$ for PRoV, and $${\geq_-}5.21$$ for PPV. Gamma irradiation was also very effective at inactivating the viruses. TGEV, PRV, PRoV, and PPV were completely inactivated to undetectable levels during the gamma irradiation. The mean log reduction factors achieved were $${\geq_-}4.65$$ for TGEV, $${\geq_-}5.87$$ for PRV, $${\geq_-}6.05$$ for PRoV, and $${\geq_-}4.89$$ for PPV. The cumulative log reduction factors achieved using the two different virus inactivation processes were $${\geq_-}9.30$$ for TGEV, $${\geq_-}11.68$$ for PRV, $${\geq_-}12.33$$ for PRoV, and $${\geq_-}10.10$$ for PPV. These results indicate that the manufacturing process for porcine bone HA from porcine-bone material has sufficient virus-reducing capacity to achieve a high margin of virus safety.