• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1744-1751
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• 2011

The concept of the advanced concept technology demonstration (ACTD) has previously been introduced in USA in order to make it possible to rapidly transfer advanced technologies developed in commercial sectors to develop weapon systems in the defense area. Since then in Korea several ACTD programs have been developed and being carried out However, there are few program management methods suitable for the characteristics of the ACTD programs, which requires stringent management of the program requirements and risks due to the radically shortened development time. In this paper such a problem has been addressed and as a solution approach the quality function deployment (QFD) method has been adopted, which is being served as a successful model in various areas such as manufacturing. The QFD method is used in our study to improve communication between various stakeholders involved in the ACTD programs and also to reduce risks related to requirements. Specifically we have developed the ACTD standard templates based on the QFD method and discussed how to use the developed templates. Finally, the application of the study result is demonstrated through the ACTD program of flight information demonstration system and also specific ways are suggested to use the standard templates, to manage requirements, and to reduce risks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11C
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• pp.1085-1097
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• 2009

We present a structure and design method of the D8PSK modem compatible with the VDL mode-2 standard and performance test results of the developed modem. In VDL mode-2, the raised cosine filter is used only in the transmitter and a general low pass filter is used in the receiver. Consequently, we can not achieve ISI reduction but can have better spectrum characteristics. Although there is 1~2 dB performance degradation with an un-matched filter compared to that with a matched filter, it is more important to minimize adjacent channel interference in narrow band communications. The transmit signal is generated digitally to avoid the problems(I/Q imbalance and DC offset etc.) of analog modulators. In addition the digital down converter using digital IF sampling technique is adopted for the receiver. This paper contains the overall configuration, design method and simulation results based in part on the previously proposed structures and algorithms. It is confirmed that the modem transmits and receives messages successfully at a speed of max. 870 km/h over ranges of up to 310 km through the ground and in-flight communication tests.

• Journal of Korean Society of Forest Science
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• v.106 no.1
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• pp.100-109
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• 2017

This study was conducted for preliminary survey and management support for Pine Wood Nematode (PWN) suppression. We took areal photographs of 6 areas for a total of 2,284 ha during 2 weeks period from 15/02/2016, and produced 6 ortho-images with a high resolution of 12 cm GSD (Ground Sample Distance). Initially we classified 423 trees suspected for PWN infection based on the ortho-images. However, low accuracy was observed due to the problems of seasonal characteristics of aerial photographing and variation of forest stands. Therefore, we narrowed down 231 trees out of the 423 trees based on the initial classification, snap photos, and flight information; produced thematic maps; conducted field survey using GNSS; and detected 23 trees for PWN infection that was confirmed by ground sampling and laboratory analysis. The infected trees consisted of 14 broad-leaf trees, 5 pine trees (2 Pinus rigida), and 4 other conifers, showing PWN infection occurred regardless of tree species. It took 6 days for 2.3 men from to start taking areal photos using UAV (Unmanned Aerial Vehicle) to finish detecting PNW (Pine Wood Nematode) infected tress for over 2,200 ha, indicating relatively high efficacy.

• Analytical Science and Technology
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• v.28 no.4
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• pp.278-287
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• 2015

Phosphodiesterase type 5 inhibitors (PDE-5 inhibitors) are used in the treatment of erectile dysfunction. In recent years, a number of reports have been conducted on dietary supplements contaminated with PDE-5 analogues. In this study, 58 analogues of PDE-5 inhibitors were sorted into five groups: tadalafil, sildenafil, hongdenafil, vardenafil, and other analogues. These analogues were then evaluated using a liquid chromatography-quadrupole-time of flight mass spectrometry (LC-QTOF-MS) electrospray ionization mass method. Each compound has a unique fragmentation ion, which can be easily analyzed qualitatively. The fragmentation pathways of the analogues were elucidated based on the QTOF-MS and MS/MS data. Common ions were confirmed for each group by analyzing the structural characteristics and fragmentation pathways. Specifically, common ions were observed at m/z 169.08 and 135.04 (tadalafil analogues), m/z 311.15 and 283.12 (sildenafil analogues and hongdenafil analogues), and m/z 312.16 and 151.09 (vardenafil analogues). The advantage of this method is that the structure of unknown components can be determined by interpreting the product ions. Hence, the developed method can be used for the identification of unknown compounds. Fragmentation pathways may also aid in the detection and identification of PDE-5 inhibitor analogues.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.2
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• pp.155-164
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• 2014

Carbon-fiber-reinforced plastic (CFRP) composites are increasingly being used in a variety of industry applications, such as aircraft, automobiles, and ships because of their high specific stiffness and high specific strength. Aircraft are exposed to high temperatures and high humidity for a long duration during flights. CFRP materials of the aircraft can absorb water, which could decrease the adhesion strength of these materials and cause their volumes to change with variation in internal stress. Therefore, it is necessary to estimate the characteristics of CFRP composites under actual conditions from the viewpoint of aircraft safety. In this study air-coupled ultrasonic testing (ACUT) was applied to the evaluation of water absorption properties of CFRP composites. CFRP specimens were fabricated and immersed in distilled water at $75^{\circ}C$ for 30, 60, and 120 days, after which their ultrasonic images were obtained by ACUT. The water absorption properties were determined by quantitatively analyzing the changes in ultrasonic signals. Further, shear strength was applied to the specimens to verify the changes in their mechanical properties for water absorption.

• Journal of Science and Technology Studies
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• v.4 no.2 s.8
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• pp.103-127
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• 2004

This paper analyzes the strategic planning process of NASA (National Aeronautics and Space Administration) including its center, GSFC (Goddard Space Flight Center) in the framework of strategic planning in publicly funded R&D organizations. To construct this framework, theories have been considered mainly focused on strategic management and planning, its application on public sector, and characteristics of R&D activities. As a result, the framework could be set up in accordance with the process of strategic planning. Also, as a case study, we explored the practice of strategic planning process and organizational implementation of NASA and GSFC. During the analysis on the strategic process of NASA and GSFC, we could draw some lessons out as follows: First, we should consider the differences between private and public sectors when we establish strategic planning in public sector. Second, the stakeholder analysis should be involved in setting the mission, goals, and strategies of an organization. Third, it is necessary to identify and assess the socio-economic effects or public benefits by R&D programs of the organization and use the feedback on its goal. Fourth, to implement strategic planning effectively, planning process should be closely integrated with the management process such as setting goals, securing budgets, and evaluating the organization. Conclusively, the analysis on NASA and GSFC contribute to implementing strategic planning in publicly funded R&D organizations by providing the appropriately modified framework. As an extension of this study, more deliberate analysis on various practices of strategic planning and performance indicators should be followed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.488-494
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• 2019

Precision Guided Missiles after production and militarization have various characteristics that enable the final performance to be identified by conducting live-fire tests after long-term storage. Likewise, the performance and reliability of ${\bigcirc}{\bigcirc}$ Missiles, which are currently used by the Korean Navy, are also verified consistently by conducting live-fire tests after militarization. Specially, the live fire test at '00 year, which was conducted by Korean Navy, showed the result that 'Ring', which is a component of the canister's front cover, was jammed with wings for propulsion and then broke away from the canister during the missile launch process. This situation led to an interruption of the deployment of wings and finally affected the missile's flight performance. The results of a survey of the canisters of those missiles whose live fire tests were conducted successfully, based on the live fire test at '00 year, showed the 'Ring's separation from canisters. This raises recognition for the need to solve the problems of 'Ring's separation and breakaway. This study suggests an improvement derived by the result of live-fire tests and introduces the effect of final launch performance of ${\bigcirc}{\bigcirc}$ Missiles and test result after applying the improvement.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.12
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• pp.1019-1025
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• 2021

In nearly all space environments, the solar cell degradation is dominated by protons[1]. Even through a GEO orbit lines in the electron radiation belts, the protons emitted from any solar event will still dominate the degradation[1]. Since COMS launch on June 26 2010, the proton events with the fluence of more than approximately 30 times the average level of perennial observations were observed between January 23 - 29 2012 and March 07 - 14 2012[16]. This paper studies the solar cell degradation by solar proton events in January and March 2012 for the open circuit voltage(Voc) of a witness cell and the short circuit current(Isc) of a section connected to a shunt switch. To evaluate the performance of solar cell, the flight data of voltage and current are corrected to the temperature, the Earth-Sun distance and the Sun angle and then compare with the solar cell characteristics at BOL. The Voc voltage dropped about 23.6mV compare after the March 2012 proton events to before the January 2012 proton events. The Voc voltage dropped less than 1% at BOL, which is 2575mV. The Isc current decreased negligible, as expected, in the March 2012 proton events.

• Korean Journal of Optics and Photonics
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• v.33 no.1
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• pp.1-10
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• 2022

In this study we introduce a new method for high-spatial-resolution continuous wave (CW) aerosol lidar that has a high spatial resolution in the near field and a low spatial resolution at long distances. A normal lidar system uses a nanosecond-pulse laser and measures the round-trip TOF between the aerosol and laser to obtain range resolution. In this study, however, we propose a new type of spatially resolving aerosol lidar that uses laser-scattering images. Using a laser-light-scattering image, we have calculated the distance of each scattering aerosol image for a given pixel, and recovered the short-range aerosol extinction. For this purpose, we have calculated the distance image and the contribution range of the aerosol to the given one-pixel image, and finally we have calculated the extinction coefficients of the aerosol with range-resolved information. In the case of traditional aerosol lidar, we can only obtain the aerosol extinction coefficients above 400 m. Using our suggested method, it was possible to extend the range of the extinction coefficient lower then several tens of meters. Finally, we can remove the unknown short-range region of pulsed aerosol lidar using our method.

• Korean Journal of Materials Research
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• v.33 no.1
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• pp.15-20
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• 2023

'Tracers' are bullets that emit light at the backside so that the shooter can see the trajectory of their flight. These light-emitting bullets allow snipers to hit targets faster and more accurately. Conventional tracers are all combustion type which use the heat generated upon ignition. However, the conventional tracer has a fire risk at the impact site due to the residual flame and has a by-product that can contaminate the inside of the gun and lead to firearm failure. To resolve these problems, it is necessary to develop non-combustion-type tracers that can convert heat to luminance, so-called 'thermoluminescence (TL)'. Here, we highly improve the thermoluminescence properties of MgB₄O₇ through co-doping of Dy³⁺+Ce³⁺ and Dy³⁺+Na⁺. The presence of doping materials (Dy³⁺, Ce³⁺, Na⁺) was confirmed by XPS (X-ray photoelectron spectroscopy). The as-synthesized co-doped MgB₄O₇ was irradiated with a specific radiation dose and heated to 500 ℃under dark conditions. Different thermoluminescence characteristics were exhibited depending on the type or amounts of doping elements, and the highest luminance of 370 cd/m² was obtained when Dy 10 % and Na 5 % were co-doped.