• 한국군사과학기술학회지
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• 제17권1호
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• pp.82-89
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• 2014

The damage in germanium (Ge) optical window irradiated by a near-infrared continuous wave (CW) laser was studied. Laser-induced heating and melting process were surveyed, and the specific laser power and the irradiance time to melt were estimated by numerical simulation. The experiments were also carried out to investigate the macro and micro structure change on Ge window. Results showed that the surface deformation was formed by melting and resolidification process, the damaged surface had a polycrystalline phase, and the transmittance as an optical performance factor in mid-infrared region was decreased. We confirmed that an abnormal polycrystalline phase and surface deformation effect such as hillock formation and roughness increase reduced the transmittance of Ge window and were the damage mechanism of CW laser induced damage on Ge window.

• 한국군사과학기술학회지
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• 제11권1호
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• pp.33-42
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• 2008

Many advanced countries including the U.S. consider defense standardization as a critical task for the efficient acquisition and effective operation of weapon systems and have implemented the appropriate standardization policy by synchronizing the defense acquisition strategies and nation standardization policy with defense standardization. It is required to develop the long-term defense standardization policy that can cope with the future domestic and international defense environmental changes. Therefore, it is an inevitable task to investigate the standardization trends and strategy in the domestic and international perspectives. The study aims to provide the vision of defense standardization policy, act/regulation, organization/personnel, education/training and information system.

• 한국군사과학기술학회지
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• 제18권3호
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• pp.293-299
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• 2015

We analyzed the damage effect on Glass Fibre Reinforced Plastics(GFRP) under air flow by irradiation of continuous wave near-IR laser. Damage process and temporal temperature distribution were demonstrated and material characteristics were observed with laser intensity, surface flow speed and angle. Surface temperature on GFRP rapidly increased with laser intensity, and the damaged pattern was different with flow characteristics. In case of no flow, penetration on GFRP by burning and flame generation after laser irradiation was appeared at once. GFRP was penetrated by the heat generated from resin ignition. In case of laser irradiation under flow, a flame generated after burning extinguished at once by flow and penetration pattern on GFRP were differently shown with flow angle. From the results, we presented the damage process and its mechanism.

• Steel and Composite Structures
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• 제23권1호
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• pp.107-114
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• 2017

Design of stepwise foam claddings subjected to air-blast is performed based on random Voronoialgorithm. FE models are constructed using the random Voronoialgorithm, and numerical analysis is carried out to simulate deformation mode and energy absorption of the cladding by the ABAQUS/Explicit software. The FE model is validated by test result, and good agreement is achieved. The deformation patterns are presented to give an insight into the influences of distribution on deformation mechanisms. The energy absorbed by the stepwise foam cladding is examined, and the parameter effects, including layer number, gradient, and blast loading, are discussed. Results indicate that the energy absorption capacity increases with the number of layer, gradient degree, and blast pressure increasing.

• 한국군사과학기술학회지
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• 제10권3호
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• pp.79-89
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• 2007

This study suggests the applicability of an AHP(Analytic Hierarchy Process) to improve the validity and fairness of evaluation index to assess the defense core-technology R&D projects. This study focused on the design of the proposal and performance evaluation index to structure them into a hierarchy using AHP which can be applicable to take the opinion of the defense R&D experts. Using the refined evaluation index, we propose a technique to enhance the reliability of the defense R&D projects evaluation system.

• 한국군사과학기술학회지
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• 제25권6호
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• pp.628-636
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• 2022

This paper describes the design of the avionics architecture for military unmanned aerial vehicles considering the airworthiness requirements for the first time. This design considers the redundancy in the system data bus and the power system and the data link system to meet the system safety requirements of the airworthiness requirements of military UAVs. This avionics architecture design has been verified through the system integration test and the flight test after manufacturing the UAV.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권12호
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• pp.3197-3218
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• 2012

Compared with traditional itinerary planning, intention-oriented itinerary recommendations can provide more flexible activity planning without requiring the user's predetermined destinations and is especially helpful for those in unfamiliar environments. The rank and classification of points of interest (POI) from location-based social networks (LBSN) are used to indicate different user intentions. The mining of vehicles' physical trajectories can provide exact civil traffic information for path planning. This paper proposes a POI category-based itinerary recommendation framework combining physical trajectories with LBSN. Specifically, a Voronoi graph-based GPS trajectory analysis method is utilized to build traffic information networks, and an ant colony algorithm for multi-object optimization is implemented to locate the most appropriate itineraries. We conduct experiments on datasets from the Foursquare and GeoLife projects. A test of users' satisfaction with the recommended items is also performed. Our results show that the satisfaction level reaches an average of 80%.

• ETRI Journal
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• 제36권2호
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• pp.329-332
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• 2014

In this letter, the problem of estimating the physical layer (PL) scrambling code sequence of DVB-S2 is studied. We present the first ever scheme to estimate the scrambling sequence. The scheme is based on hypothesis testing. By analyzing the PL scrambling process, we construct a new sequence equivalent to the scrambling sequence. We then use hypothesis testing to estimate the new sequence. The threshold for the hypothesis testing is also discussed. The experiment results show that the performance of our estimation scheme can work even under high BER.

• 한국군사과학기술학회지
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• 제26권1호
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• pp.102-112
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• 2023

This research mainly focuses on the transport and dispersion of chemical agent plume according to the Lagrangian Puff Model and Lagrangian Particle Model of NBC_RAMS(Nuclear, Biological, Chemical Reporting And Modeling S/W System). NBC_RAMS was developed with the purposes of estimating the fate of Chemical, Biological, and Radioactive(CBR) agent plumes and evaluating damages in the Republic of Korea. First, it calculates the local weather pattern, i.e. wind speed, wind direction, and temperature, by considering the effects of land uses and topography. The plume behaviors are calculated by adopting the Lagrangian Puff Model(LPFM) or Lagrangian Particle Model(LPTM). In this research, we assumed a virtual chemical agent exposure event in a stable atmospheric condition during the summer season. The plume behaviors were estimated by both LPFM and LPTM on the used area(urbanized and dry area) and the agricultural land. The higher heat flux in the used area led to stronger winds and further downward movement moving of the chemical agent than the farmland. The lateral dispersion of the chemical plume was emphasized in the Lagrangian Puff Model because it adopted Gaussian distribution.

• 한국군사과학기술학회지
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• 제9권1호
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• pp.80-88
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• 2006

The purpose of this thesis is to research and propose a practical Information Security Technical Architecture on Primary Defense Information Infrastructure with regard to requirement of information security. The scope of this research is limited to national defense information master plan & security rule, and U.S. DoD's IATF is used to plan a detailed structure. The result of this research can be used as a guide book for providing security for Army IT infrastructure now and in the future as well as to devise a plan for research and development in information protection technology.