• Journal of the Korea Society for Simulation
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• v.19 no.4
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• pp.291-299
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• 2010

As recent advances in science, technology and performance requirements of the weapons system are getting highly diversified and complex, the performance requirements also get stringent and strict. Moreover, the weapons system should be intimately connected with other systems such as watchdog system, command and control system, C4I system, etc. However, a tremendous amount of time, cost and risk being spent to acquire new weapons system, and not being diminished compared to the rapid pace of its development speed. Defense Modeling and Simulation(M&S) comes into the spotlight as an alternative to overcoming these difficulties as well as constraints. In this paper, we propose the development process of virtual test framework based on the synthetic environment as a tool to analyze the effectiveness of the weapons system of underwater engagement model. To prove the proposed concept, we develop the test-bed of virtual test using Delta3D simulation engine, which is open source S/W. We also design the High Level Architecture and Real-time Infrastructure(HLA/RTI) based Federation for the interoperation with heterogeneous simulators. The significance of the study entails (1)the rapid and easy development of simulation tools that are customized for the Korean Theater of War; (2)the federation of environmental entities and the moving equations of the combat entities to manifest a realistic simulation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.5 s.335
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• pp.61-68
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• 2005

In this paper, low conversion loss 94 GHz MIMIC resistive mixer was designed and fabricated. The $0.1{\mu}m$ InGaAs/InAlAs/GaAs Metamorphic HEMT, which is applicable to MIMIC's, was fabricated. The DC characteristics of MHEMT are 665 mA/mm of drain current density, 691 mS/mm of maximum transconductance. The current gain cut-off frequency(fT) is 189 GHz and the maximum oscillation frequency(fmax) is 334 GHz. A 94 GHz resistive mixer was fabricated using $0.1{\mu}m$ MHEMT MIMIC process. From the measurement, the conversion loss of the 94 GHz resistive mixer was 8.2 dB at an LO power of 10 dBm. P1 dB(1 dB compression point) of input and output were 9 dBm and 0 dBm, respectively. LO-RF isolations of resistive mixer was obtained 15.6 dB at 94.03 GHz. We obtained in this study a lower conversion loss compared to some other resistive mixers in W-band frequencies.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.7
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• pp.1447-1454
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• 2017

The realtime test data topic means that process for the data efficiently from many kinds of measurement device at the test range. There are many measurement devices in test range. The test range require accurate observation and determine on test object. In this realtime test data slaving framework system, the system can produce variety of test informations and all these data also must be transmitted to test information management or display system in realtime. Using RTI DDS(Data Distribution Service) middle ware Ver 5.2, we can product the efficiency of system usability and QoS(Quality of Service) requirements. So the application user enables to concentrate on applications, not middle ware. As the reason, Complex function is provided by the DDS, not the application such as Visualization Software. In this paper, I suggest the realtime test data topic on slaving framework of realtime test data based on DDS at the test range system.

• Tuberculosis and Respiratory Diseases
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• v.47 no.2
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• pp.172-183
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• 1999

Background: Nitric oxide is a short-lived effector molecule derived from L-arginine by the nitric oxide synthase(NOS). Nitric oxide plays a role in a number of physiologic and pathophysiologic functions including host defense, edema formation, and regulation of smooth muscle tone. Some kinds of cells including macrophage are known to produce large quantities of nitric oxide in response to inflammatory stimuli such as interleukin-$1\beta$(IL-$1\beta$), tumor necrosis factor-$\alpha$(TNF-$\alpha$), interferon-$\gamma$(IFN-$\gamma$) and lipopolysaccharide(LPS). Reactive oxygen species are also known to be important in the pathogenesis of acute cell and tissue injury such as acute lung injury model Methods: Using the RA W264.7 cells, we have examined the ability of oxidant hydrogen peroxide($H_2O_2$) to stimulate nitric oxide production and inducible NOS mRNA expression. Also, we have examined the effects of NOS inhibitors and antioxidants on $H_2O_2$ induced nitric oxide production. Results: Stimulation of RAW264.7 cells with combinations of 100 ng/ml IL-$1\beta$, 100 ng/ml TNF-$\alpha$, and 100 U/ml IFN-$\gamma$ or 100 U/ml IFN-$\gamma$ and $1{\mu}g/ml$ LPS induced the synthesis of nitric oxide as measured by the oxidation products nitrite($NO_2^-$) and nitrate($NO_3^-$). Addition of $250 {\mu}M-2$ mM $H_2O_2$ to the cytokines significantly augmented the synthesis of $NO_2^-$ and $NO_3^-$(p<0.05). When cells were incubated with increasing concentrations of $H_2O_2$ in the presence of IL-$1\beta$, TNF-$\alpha$ and IFN-$\gamma$ at constant level, the synthesis of $NO_2^-$ and $NO_3^-$ was dose-dependently increased(p<0.05). $N^G$-nitro-L-arginine methyl ester(L-NAME), dose dependently, significantly inhibited the formation of $NO_2^-$ and $NO_3^-$ in cells stimulated with LPS, IFN-$\gamma$ and $H_2O_2$ at constant level(p<0.05). Catalase significantly inhibited the $H_2O_2$-induced augmentation of cytokine-induced $NO_2^-$ and $NO_3^-$ formation(p<0.05). But, boiled catalase did not produce a significant inhibition in comparison with the native enzyme. Another antioxidant 2-mercaptoethanol and orthophenanthroline dose-dependently suppressed $NO_2^-$ and $NO_3^-$ synthesis(p<0.05). Northern blotting demonstrated that H:02 synergistically stimulated the cytokine-induced iNOS mRNA expression in RA W264.7. Conclusion: These results suggest that $H_2O_2$ contributes to inflammatory process by augmenting the iNOS expression and nitric oxide synthesis induced by cytokines.