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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korea Institute of Military Science and Technology
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Journal DOI :
The Korea Institute of Military Science and Technology
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Volume & Issues
Volume 19, Issue 3 - Jun 2016
Volume 19, Issue 2 - Apr 2016
Volume 19, Issue 1 - Feb 2016
Selecting the target year
A Study on Improvement of Strength Safety Factor for K55A1 APU Engine Mounts
Kim, Byung Hyun ; Seo, Jae Hyun ; Park, Young Il ; Kim, Yong Wook ; Kim, Byung Ho ;
Journal of the Korea Institute of Military Science and Technology, volume 19, issue 3, 2016, Pages 281~287
DOI : 10.9766/KIMST.2016.19.3.281
The purpose of this study is to analyze the vibration characteristics and develop a mounting which can improve the strength safety factor to replace the high failure rate APU(auxiliary power unit) imported metal mounts with rubber mount that can be domestically produced. For this study, we analyzed in 3 kinds of rubber mounts hardness for the natural frequency to avoid the average excited frequency of the APU. In addition, allowed vibration acceleration of rubber mount confirmed to 90.8 g by adding a strength safety factor. To assure the validity of the design, we measure the vibration acceleration equipped with a metal mount and rubber mount 2 species(Hs 50 and 60). As a result, the proposed design method in this study is reasonable because the rubber mounts is excellent strength safety factor and vibration transmissibility than metal mounts.
Electronic Image Stabilization for Portable Thermal Image Camera
Kim, Jong-ho ;
Journal of the Korea Institute of Military Science and Technology, volume 19, issue 3, 2016, Pages 288~293
DOI : 10.9766/KIMST.2016.19.3.288
Electronic Image Stabilization(EIS) is widely used as a technique for correcting a shake of an image. The case requiring the EIS function has been increased in high magnification thermal image observation on portable military equipment. Projection Algorithm(PA) for EIS is easy to implement but its performance is sensitive to the projection area. Especially, projection profiles of thermal image have very modest change and are difficult to extract image shifts between frames. In this paper, we proposed algorithm to extract a feature image for the thermal image and compared Block Matching Algorithm(BMA) with PA using our proposed feature image. When using our proposed feature image, BMA was simply implemented using FPGA`s internal small memory. And we were able to obtain 30 % PSNR improved results compared to PA.
Design of Transparent Electromagnetic Absorbing Structure using Metal Grid Mesh Printing
Yoon, Sun-Hong ; Lee, Jun-Sang ; Lee, In-Gon ; Hong, Ic-Pyo ;
Journal of the Korea Institute of Military Science and Technology, volume 19, issue 3, 2016, Pages 294~301
DOI : 10.9766/KIMST.2016.19.3.294
In this paper, we designed the transparent circuit analog radar absorbing structure using printed metal grid mesh for enhanced optical transmittance. To obtain wideband electromagnetic absorption and enhanced optical transparency at X-band, we proposed the resistive FSS(Frequency Selective Surface) using printed metal mesh pattern on transparent glass with PEC(Perfect Electric Conductor) plane using ITO(Indium Thin Oxide) coating. We then fabricated the proposed structure to verify the simulation results obtained from commercial EM simulator. The comparisons between the simulation and measured results show good agreements. The results also show that the proposed radar absorbing structure can provide wideband reflection as well as better optical transparency. We can apply this proposed structure to the canopy of stealth aircraft and other stealth and security applications for visible transparency.
A Study on the Calculation of the Design Loads for Blast Doors of Underground Ammunition Facilities Using M&S
Park, Young Jun ; Baek, Jonghyuk ; Son, Kiyoung ;
Journal of the Korea Institute of Military Science and Technology, volume 19, issue 3, 2016, Pages 302~310
DOI : 10.9766/KIMST.2016.19.3.302
An underground ammunition facility requires less quantity distances than the aboveground counterpart. However, chamber blast doors which resist the high blast-pressures are necessary for prevention of the consecutive explosions when an accident explosion occurs at any chamber. This paper aims to propose an procedure for calculation of the design loads for the chamber blast doors. Modeling considerations are drawn through analyzing the influences of the geometrical shapes and mechanical properties of rocks on the propagation of pressure wave along with the tunnels. Additionally, the design loads for the chamber blast doors in a newly-built underground ammunition facility are calculated based on the proposed procedure.
Storage Life Estimation of Next Infrared Flare Material
Back, Seungjun ; Son, Youngkap ; Kim, Namjin ; Kwon, Taesoo ;
Journal of the Korea Institute of Military Science and Technology, volume 19, issue 3, 2016, Pages 311~318
DOI : 10.9766/KIMST.2016.19.3.311
This paper shows storage life estimation of next IR(infrared) flare material through accelerated degradation tests. Three temperature conditions for the accelerated degradation tests are 55, 65 and
. Six performances of IR flare material are burning time, IR peak/continuous Intensity, total energy of near/mid-IR and color ratio, and they were measured after the tests. Storage life of the IR flare material was estimated through both analyzing the degradation data of those performances and applying distribution-based degradation models to the data. Over 30 years of storage life at
is estimated in terms of IR peak intensity with reliability 0.99 and confidence level 99 %. Additionally, 10 years of storage period at
would be equivalent to 68 days of accelerated test at
from the activation energy in Arrhenius model.
Polynigrogen Energetic Materials
Lee, Junwung ;
Journal of the Korea Institute of Military Science and Technology, volume 19, issue 3, 2016, Pages 319~329
DOI : 10.9766/KIMST.2016.19.3.319
Current research trends of prediction of possible structures, synthesis and explosive characteristics of polynitrogen molecules(PNs) are reviewed. Theoretically PNs are composed only of nitrogen atoms, in which N-N bonds are either single or double bonds, and thus when these molecules decompose, release of enormous energy is accompanied. From the middle of 20th century energetic material chemists have been seeking possible structures and the methods of synthesis of these new materials. As a results, from
together with their ions are predicted, and experimental chemists have been trying to synthesize these materials with a few success, including the famous
ion in 1999. Although experimental successes are very rare beyond
until today, the author believes that renovative ideas together with sincere efforts will bring someday next generation of high energy materials such as nitrogen fullerene(
) in reality.
Numerical Analysis of the Ballistic Performance and Behavior of STF-Impregnated Multi-layer Fabrics
Mun, Sang Ho ; Son, Kwon Joong ; Cho, Hee Keun ; Park, Jong Kyoo ; Jeong, Euigyung ; Lee, Man Young ; Kim, See Jo ;
Journal of the Korea Institute of Military Science and Technology, volume 19, issue 3, 2016, Pages 330~338
DOI : 10.9766/KIMST.2016.19.3.330
Impregnation of shear-thickening fluid(STF) into high-strength fabrics makes a considerable improvement on the ballistic performance of fabric armors. Understanding dissipation augmentation due to shear thickening effects on yarn-yarn and yarn-projectile friction is of great importance in liquid armor research. This paper takes a shearthickening effect into account in numerical simulations by using a velocity-dependent friction model. Impact simulations were performed to validate the friction model as well as to evaluate the ballistic performance of STF-fabrics. Impact simulations on neat fabrics were also conducted to provide baseline results for comparison.
Numerical Analysis of Pressure Propagation to the Main Charge by Warhead Penetration into Concrete Targets
Yun, Kyung Jae ; Yoo, Yo-Han ;
Journal of the Korea Institute of Military Science and Technology, volume 19, issue 3, 2016, Pages 339~345
DOI : 10.9766/KIMST.2016.19.3.339
This paper is concerned with the numerical simulation result of pressure propagation to the main charge by warhead penetration into concrete targets. In this study, we developed on-line pressure measurement method in the main charge during warhead penetration. Using the on-line pressure measurement method, we successfully recorded the pressure-time history in the main charge during the field penetration test. Then we compared result of numerical simulations with test data and found that the simulation results are in good agreement with the test results. Finally, through the numerical calculations it is concluded that the installation of liner is effective in reducing pressure level produced in the main charge.
Analysis on the Distribution of RF Threats Using Unsupervised Learning Techniques
Kim, Chulpyo ; Noh, Sanguk ; Park, So Ryoung ;
Journal of the Korea Institute of Military Science and Technology, volume 19, issue 3, 2016, Pages 346~355
DOI : 10.9766/KIMST.2016.19.3.346
In this paper, we propose a method to analyze the clusters of RF threats emitting electrical signals based on collected signal variables in integrated electronic warfare environments. We first analyze the signal variables collected by an electronic warfare receiver, and construct a model based on variables showing the properties of threats. To visualize the distribution of RF threats and reversely identify them, we use k-means clustering algorithm and self-organizing map (SOM) algorithm, which are belonging to unsupervised learning techniques. Through the resulting model compiled by k-means clustering and SOM algorithms, the RF threats can be classified into one of the distribution of RF threats. In an experiment, we measure the accuracy of classification results using the algorithms, and verify the resulting model that could be used to visually recognize the distribution of RF threats.
Additional Preamble Definitions for Systems Based on IEEE 802.16 Standard
Eom, Jaehyung ; Seo, Sungwon ; Lee, Sungmin ;
Journal of the Korea Institute of Military Science and Technology, volume 19, issue 3, 2016, Pages 356~362
DOI : 10.9766/KIMST.2016.19.3.356
IEEE 802.16 standard(WiMAX) is one of 3.5G/4G wireless technologies and there are many systems based on the standard. Each frame of the systems begins with a preamble for synchronization and channel estimation, etc. IEEE 802.16 standard defines a total of 114 preamble sequences. By the way there are some systems(such as mobile multi-hop relay) that require using more than 114 preamble sequences. So we define 114 additional preamble sequences in this paper. And we evaluate PAPR and cross-correlation performance of them to decide to be usable as a preamble.
Coupler Implementation and Antenna Tracking Accuracy Analysis for Ku-band Multi-mode Monopulse Satellite Tracking System
Lee, Jaemoon ; Lim, Jaesung ; Park, Dohyun ;
Journal of the Korea Institute of Military Science and Technology, volume 19, issue 3, 2016, Pages 363~370
DOI : 10.9766/KIMST.2016.19.3.363
This paper proposes a Ku-band multi-mode coupler and its monopulse tracking system, which can be applied to a unmaned aircraft vehicle(UAV) platform. In general, the carrier-to-noise(C/N) level of the beacon signal from a Ku-band commercial satellite is relatively weak compared to that of a military satellite because the Ku-band satellite has been designed for commercial services. Therefore, this paper proposes a coupler and its multi-mode monopulse tracking system satisfying the tracking accuracy under a low C/N environment and analyzes the tracking accuracy. After that, we perform a real satellite tracking test and compare the accuracy of the test with the analysis result before validating the performance of the architecture of the proposed satellite tracking system.
Design and Analysis of Weapon Simulator using Schedulability Analysis
Jang, Tasksoo ; Kim, Yongho ; Na, Beomcheol ; Park, Keunkuk ;
Journal of the Korea Institute of Military Science and Technology, volume 19, issue 3, 2016, Pages 371~378
DOI : 10.9766/KIMST.2016.19.3.371
The most important things in real-time systems are that a system guarantees to meet its deadline and to operate in its predictable range. When we design a real-time system, we need to verify whether the system can meet its deadline through schedulability analysis. There are several kinds of schedulability analysis technique for fixed priority scheduling systems. But as we all know, we can`t perform schedulability analysis in design time because we can`t estimate upper bounds on execution time of each task. So we used a similar real-time system to estimate upper bounds on execution time for our system, and then we performed schedulability analysis and verified that our system designed can meet its deadline.
Phase Noise Analysis of 2.4 GHz PLL using SPD
Chae, Myeoung-ho ; Kim, Jee-heung ; Park, Beom-jun ; Lee, Kyu-song ;
Journal of the Korea Institute of Military Science and Technology, volume 19, issue 3, 2016, Pages 379~386
DOI : 10.9766/KIMST.2016.19.3.379
In this paper, phase noise analysis result for 2.4 GHz PLL(phase locked loop) using SPD(sample phase detector) is proposed. It can be used for high performance frequency synthesizer`s LO(local oscillator) to extend output frequency range or for LO of offset PLL to reduce a division rate or for clock signal of DDS(direct digital synthesizer). Before manufacturing, theoretical estimation of PLL`s phase noise performance should be performed. In order to calculate phase noise of PLL using SPD, Leeson model is used for modeling phase noise of VCO(voltage controlled oscillator) and OCXO(ovened crystal oscillator). After theoretically analyzing phase noise of PLL, optimized loop filter bandwidth was determined. And then, phase noise of designed loop filter was calculated to find suitable OP-Amp. Also, the calculated result of phase noise was compared with the measured one. The measured phase noise of PLL was -130 dBc/Hz @ 10 kHz.
A Design of the New Robust Disturbance Observer
Park, Jukwang ;
Journal of the Korea Institute of Military Science and Technology, volume 19, issue 3, 2016, Pages 387~394
DOI : 10.9766/KIMST.2016.19.3.387
This paper proposes a new disturbance observer(DOB). The purpose of the DOB is to realize the plant performing like a model in the presence of disturbances which come from external environment and inherent nonlinearities and uncertainties in the plant. It is shown that the proposed DOB compensates those disturbances, nonlinearities and uncertainties, effectively. And it is theoretically proved that the proposed DOB can be guaranteed its stability for the stable plant. Its availability is shown by applying the DOB to the stabilization platform for EOTS(Electro Optical Tracking System).
Motion Analysis of an Underwater Vehicle Running near Wave Surface
Yoon, Hyeon Kyu ; Ann, Seong Phil ; Jung, Chulmin ; Kim, Chan-Ki ;
Journal of the Korea Institute of Military Science and Technology, volume 19, issue 3, 2016, Pages 395~403
DOI : 10.9766/KIMST.2016.19.3.395
A cylinder-type underwater vehicle for military use that is running near the free surface at the final homing stage to hit a surface ship target is affected by wave force and moment. Since wave can affect an underwater vehicle running at the depth less than half of the modal wave length, it is important to confirm that the underwater vehicle can work well in such a situation. In this paper, wave force and moment per unit wave amplitude depending on wave frequency, wave direction, and vehicle`s running depth were calculated by 3-Dimensional panel method, and the numerical results were modeled in external force terms of six degrees of freedom equations of motion. Motion simulation of the underwater vehicle running in various speed, depth, and sea state were performed.
Classification and Evaluation Method for Autonomy Levels of Unmanned Maritime Systems
Kwon, Laeun ;
Journal of the Korea Institute of Military Science and Technology, volume 19, issue 3, 2016, Pages 404~414
DOI : 10.9766/KIMST.2016.19.3.404
Autonomy of unmanned systems is important because the unmanned system with high level of autonomy is able to perform desired tasks in unstructured environments without continuous human guidance. Evaluation of their autonomy is vital to realize the autonomous operation ability of unmanned system. Compared to the methods of evaluating the level of autonomy(LOA) for an unmanned ground vehicle(UGV) and unmanned aerial vehicle(UAV), the method of expressing the LOA of unmanned maritime system(UMS) is not established yet. Since UMS has a unique characteristics in terms of operational area, mission complexity and required technologies, compared to the UGV and UAV, it is required to establish for expressing the LOA for UMS. This paper reviews the current approaches to assess the LOA of unmanned system and proposes potential metrics for UMS in order to determine the autonomy levels of UMS.