• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.1
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• pp.70-78
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• 2013

Before GBAS ground systems is installed at the airport, the site survey is needed to determine the suitability of proposed GBAS candidate sites depending on the siting requirements. Therefore, analysis of GPS signal reception environment, one of the site survey steps, is required. In this paper, the number of visible satellites, GPS signal strength, multipath error, radio frequency interference and predicted availability were analyzed using the GPS data of Gimpo International Airport measured by PortaSAT equipments and the analysis results were represented.

• Journal of Navigation and Port Research
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• v.37 no.1
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• pp.49-54
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• 2013

This paper describes the progress and results of 'Wide Area Differetial GNSS (WA-DGNSS) Development' project which is supported by Korea Ministry of Land, Transport and Maritime Affairs. This project develops the main algorithm of the WA-DGNSS which can guarantee the improved accuracy, availability and integrity all over the Korean peninsula. After the establishment of WA-DGNSS ground system, a real time demonstration using pseudolite will be conducted. Product of this project will be directly utilized in Korean Satellite Based Augmentation System(SBAS) development project which is planned to be started from 2014.

• IMMUNE NETWORK
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• v.2 no.2
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• pp.109-114
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• 2002

Background: To investigate the role of sympathetic nervous system (SNS) in moxibustion-induced immunomodulation, the effects of chemical sympathectomy on moxibustion-induced changes in splenic NK cell cytotoxicity, T and B cell proliferation were studied in Sprague-Dawley male rats. Methods: Chemical sympathectomy was achieved with intraperitoneal injection of 6-hydroxydopamine 50 mg/kg/day for 3 successive days. Direct moxibustion (6-minute interval, 9 moxa ball, each of which weighing 0.007 g and burning for 40 seconds) was applied on unilateral anterior tibial muscle region where Zusanli (ST36) acupoint is located, once a day for 7 successive days. NK cell cytotoxicity was measured by $4hr-^{51}Cr$ release assay. Mitogen-induced lymphocyte proliferation was analyzed by [$^3H$]-thymidine incorporation assay. Results: NK cell cytotoxicity was suppressed by moxibustion, more in sympathectomized rats than in vehicle-treated rats. T cell proliferation induced by concanavalin A was not affected by moxibustion. B cell proliferation induced by lipopolysaccharide showed no significant change in vehicle-treated rats, but an increase in sympathectomized rats by moxibustion. Sympathectomy alone induced augmentation of NK cell cytotoxicity and suppression of T cell proliferation. Conclusion: These results suggest that SNS has no direct relation with moxibution-induced immunomodulation but has an important role in the mechanism to keep the homeostasis of immune system by tonically inhibiting excessive changes of various immune components.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.11
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• pp.1111-1117
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• 2012

Implants for rhinoplasty should ideally be biocompatible and possess long-term stability after implantation. Silicone implants are most widely used for rhinoplasty. However, these implants suffer from problems related to high extrusion and infection rates. To minimize these complications, we propose a novel augmentation rhinoplasty technique using tissue engineering. To demonstrate its feasibility, a nasal-implant-shaped scaffold was designed using commercialized CAD software and fabricated using a Multi-head Deposition System, which is a solid freeform fabrication system that dispenses material. In vitro cell proliferation and chondrogenic differentiation tests were carried out using nasal septal chondrocytes.

• Journal of Navigation and Port Research
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• v.37 no.3
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• pp.263-267
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• 2013

This paper describes the progress and the plan of 'Wide Area Differential GPS (WA-DGPS) Development' project supported by Korean Ministry of Oceans and Fisheries. The project develops the main algorithms of the WA-DGPS which guarantees the improved accuracy, availability, and integrity all over the Korean peninsula. After the establishment of WA-DGPS ground infrastructure system, a real-time demonstration using pseudolite installed on the ground will be conducted in the final year. Also, the development of Korean Satellite-based Augmentation System (SBAS) is expected to be started from 2014, and the algorithms and the results in the WA-DGPS project will be used in the SBAS development.

• Archives of Plastic Surgery
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• v.33 no.6
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• pp.688-694
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• 2006

Purpose: Reconstruction of the craniofacial defects can be carried out with autogenous tissues, allogenic implants, or alloplastic materials. Titanium mesh systems have been used for bony reconstruction in non load-bearing areas. They offer several advantages: immediate availibility without any donor site morbidity, easy handling, stable 3-D reconstruction, and low susceptibility to infection. The aim of this study is to evaluate the usefulness and complications of titanium mesh system in the reconstruction of the craniofacial defects. Methods: From Jan. 2000, to Dec. 2004, we performed reconstruction of craniofacial bone defects in 21 patients who had benign or malignant tumor and fracture events in the cranium, orbit, nasal bone, maxilla, zygoma and the mandible. The size of the defects ranged from $1.0{\times}1.5cm$ to $12{\times}10cm$. Two different mesh systems, micro-titanium augmentation mesh and dynamic mesh was used for bony reconstruction in non load-bearing areas. The patients were evaluated from 1 to 4 yrs clinically and radiographically with a mean follow up period of 1.5 yrs. Results: There were no serious complications, including wound infection, foreign body reaction, exposures or loos of the mesh, central infection and pathologic findings of bone around mesh exception of one patient, who had expired of skull base tumor recurrence. Long-term stability of the reconstructions and the overall functional and aesthetic outcome was excellent. Conclusion: Our experiences demonstrate that the Titanium mesh system is a relatively safe and efficient method in the craniofacial reconstruction and have broadens our choices of therapeutic procedures in the craniomaxillofacial surgery.

• Nutrition Research and Practice
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• v.10 no.4
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• pp.371-376
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• 2016

BACKGROUND/OBJECTIVES: Chronic ultraviolet (UV) exposure-induced reactive oxygen species (ROS) are commonly involved in the pathogenesis of skin damage by activating the metalloproteinases (MMP) that break down type I collagen. Adenophora remotiflora (AR) is a perennial wild plant that inhabits Korea, China, and Japan. The present study investigated the protective effects of AR against UVB-induced photo-damage in keratinocytes. MATERIALS/METHODS: An in vitro cell-free system was used to examine the scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical and nitric oxide (NO). The effect of AR on ROS formation, antioxidant enzymes, elastase, MMP-1 level, and mRNA expression of MMP-1 were determined in UVB-irradiated human keratinocyte HaCaT cells. RESULTS: AR demonstrated strong DPPH free radical and NO scavenging activity in a cell-free system exhibiting $IC_{50}$ values of 1.88 mg/mL and 6.77 mg/mL, respectively. AR pretreatment dose-dependently attenuated the production of UVB-induced intracellular ROS, and antioxidant enzymes (catalase and superoxide dismutase) were enhanced in HaCaT cells. Furthermore, pretreatment of AR prevented UVB-induced elastase and collagen degradation by inhibiting the MMP-1 protein level and mRNA expression. Accordingly, AR treatment elevated collagen content in UVB-irradiated HaCaT cells. CONCLUSION: The present study provides the first evidence of AR inhibiting UVB-induced ROS production and induction of MMP-1 as a result of augmentation of antioxidative activity in HaCaT human keratinocytes. These results suggest that AR might act as an effective inhibitor of UVB-modulated signaling pathways and might serve as a photo-protective agent.

• Structural Engineering and Mechanics
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• v.40 no.3
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• pp.431-451
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• 2011

Time delay inevitably exists in active control systems, and it may cause the degradation of control efficiency or instability of the systems. So time delay needs to be compensated in control design in order to eliminate its negative effect on control efficiency. Today time delay in linear systems has been more studied and some treating methods had been worked out. However, there are few treating methods for time delay in nonlinear systems. In this paper, an active controller for a nonlinear and hysteretic building structure with time delay is studied. The nonlinear and hysteretic behavior of the system is illustrated by the Bouc-Wen model. By specific transformation and augmentation of state parameters, the motion equation of the system with explicit time delay is transformed into the standard state space representation without any explicit time delay. Then the fourth-order Runge-Kutta method and instantaneous optimal control method are applied to the controller design with time delay. Finally, numerical simulations and comparisons of an eight-story building using the proposed time-delay controller are carried out. Simulation results indicate that the control performance will deteriorate if time delay is not taken into account in the control design. The simulations also prove the proposed time delay controller in this paper can not only effectively compensate time delay to get better control effectiveness, but also work well with both small and large time delay problems.

• Progress in Medical Physics
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• v.30 no.2
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• pp.49-58
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• 2019

Purpose: Automated analytical systems have begun to emerge as a database system that enables the scanning of medical images to be performed on computers and the construction of big data. Deep-learning artificial intelligence (AI) architectures have been developed and applied to medical images, making high-precision diagnosis possible. Materials and Methods: For diagnosis, the medical images need to be labeled and standardized. After pre-processing the data and entering them into the deep-learning architecture, the final diagnosis results can be obtained quickly and accurately. To solve the problem of overfitting because of an insufficient amount of labeled data, data augmentation is performed through rotation, using left and right flips to artificially increase the amount of data. Because various deep-learning architectures have been developed and publicized over the past few years, the results of the diagnosis can be obtained by entering a medical image. Results: Classification and regression are performed by a supervised machine-learning method and clustering and generation are performed by an unsupervised machine-learning method. When the convolutional neural network (CNN) method is applied to the deep-learning layer, feature extraction can be used to classify diseases very efficiently and thus to diagnose various diseases. Conclusions: AI, using a deep-learning architecture, has expertise in medical image analysis of the nerves, retina, lungs, digital pathology, breast, heart, abdomen, and musculo-skeletal system.

• The Journal of Korean Medicine
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• v.37 no.2
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• pp.23-35
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• 2016

Objectives: The objective of this study is to demonstrate the cardioprotective effects of Salvia Miltiorrhiza Radix (SMR) on the pressure overload (PO)-induced heart failure (HF) by transverse aortic constriction (TAC) in C57BL/6 mice through possible antioxidant effects. Methods: The mortality, body and heart weights, antioxidant defense system of the heart and histopathology of heart were analyzed. The obtained results were compared with resveratrol, in which potent cardioprotective effects on TAC mice model were already proved at a dose level of 10 mg/kg by antioxidant effects, as reference in this experiment. Results: Significant increases of mortalities, heart weights, and hypertrophic, lytic and focal fibrotic histological changes in the left ventricles were found with defects of heart antioxidant defense systems - the increases of heart cortex MDA contents, decreases of GSH contents, SOD and CAT activities in TAC control mice as compared with sham vehicle control mice, respectively. However, these HF signs induced by TAC surgery through PO and destroys heart antioxidant defense systems were significantly and dose-dependently inhibited by 14 days continuous oral treatment of SMR 500, 250 and 125 mg/kg, similar to those of resveratrol 10 mg/kg in SMR 125 mg/kg. Conclusions: The results obtained in this study propose that oral administration of SMR potently alleviates PO-induced HF by TAC, through augmentation of heart antioxidant defense system.