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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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The Korea Institute of Military Science and Technology
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Volume & Issues
Volume 11, Issue 6 - Dec 2008
Volume 11, Issue 5 - Oct 2008
Volume 11, Issue 4 - Aug 2008
Volume 11, Issue 3 - Jun 2008
Volume 11, Issue 2 - Apr 2008
Volume 11, Issue 1 - Feb 2008
Selecting the target year
The Characteristics of Open-loop Trajectory and Time-to-go Estimation for Impact Angle Control Optimal Guidance through Inverse Optimal Problem
Lee, Yong-In ; Lee, Jin-Ik ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 5~12
This paper presents the features of an impact angle constrained open-loop optimal trajectory which is given by a function of initial conditions and optimal guidance gains. Using missile motion described by linearized kinematic equations and a proper form of performance index, an inverse optimal problem is suggested to investigate the gains related to the performance index. The flight trajectory and time-to-go can be shaped in terms of the optimal guidance gains. The results are evaluated by 3-DOF simulation.
Analysis of Launching Dynamics Using Finite Element Method
Lee, Hak-Yeol ; Song, Oh-Seop ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 13~18
During the launching phase, a launcher is vibrated by launching forces and as a result, the vibrating launcher affects the behavior of the missile. One of the important performances of the launcher is that the launched missile should be in a stable condition at the launching stage. In this paper, the launcher vibration at the launching phase is investigated in order to secure the stable flight of the missile. Using the finite element method, launching dynamics is investigated to analyze the behaviors of the launcher and missile considering the effect of the launcher vibration. In addition, performance of consecutive launching and launching dynamics of the launcher which launches missiles consecutively are studied for the various conditions after first launch.
Performance Comparison of Image Transmission in Underwater Acoustic Environment
Lee, Seung-Woo ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 19~29
Underwater acoustic(UWA) communication is one of the most difficult field in terms of severe channel environments such as multipath propagation, high temporal and spatial variability of channel conditions. Therefore, it is important to model and analyze the characteristics of underwater acoustic channel such as multipath propagation, transmission loss, reverberation, and ambient noise. In this paper, UWA communication channel is modeled with a ray tracing method and applied to image transmission. Quadrature phase shift keying(QPSK) and multichannel decision feedback equalizer(DFE) are utilized as phase-coherent modulation method and equalization technique, respectively. The objective is to improve the performance of the image transmission using vertical sensor array instead of single sensor in the viewpoint of bit error rate(BER), constellation diagram, and received image quality.
A Real-Time NDGPS/INS Navigation System Based on Artificial Vision for Helicopter
Kim, Jae-Hyung ; Lyou, Joon ; Kwak, Hwy-Kuen ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 30~39
An artificial vision aided NDGPS/INS system has been developed and tested in the dynamic environment of ground and flight vehicles to evaluate the overall system performance. The results show the significant advantages in position accuracy and situation awareness. Accuracy meets the CAT-I precision approach and landing using NDGPS/INS integration. Also we confirm the proposed system is effective enough to improve flight safety by using artificial vision. The system design, software algorithm, and flight test results are presented in details.
Simulated Radar Target Generation Equipment(SRTGE) for Evaluating Radar System Performance
Yang, Jin-Mo ; Lee, Min-Joon ; Kim, Whan-Woo ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 40~49
In this paper, we have described a Simulated Radar Target Generation Equipment(SRTGE) for evaluating the performance of a developed radar system. In order to change a simulated target range(or time delay), the variable optical delay line structure is used in SRTGE, In addition, SRTGE is required to generate a target return signal which is composed of variable amplitude and Doppler velocity. The interference such as noise jamming and clutter is also produced from SRTGE for evaluating ECCM(Electronic-Counter-Counter Measure) capability of radar.
A Study on a Tracking Method of Telemetry Signal using Self-Slaving
Lee, Sung-Pil ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 50~57
A telemetry ground station has a highly directional, parabolic tracking antenna to receive a weak telemetry signal from a target at a distance. The tracking antenna with narrow beam-width normally uses the auto-track method for the target tracking. This paper presents several issues in the auto-track method and introduces a new tracking method using Self-Slaving technique. Self-Slaving means that the tracking antenna is slaved to not data measured by RADAR but GPS/INS informations received by the telemetry system for pointing. The Self-Slaving method shows good performance in comparison with auto-track method.
Development of Control and Analysis Software for Electronic Warfare Test System Using Reverse Engineering of Network Protocol
Jung, In-Hwa ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 58~66
In this paper, we have proposed a method and procedure which can find out the unknown network protocol. Although it seems to be difficult to identify the protocol, we can find out the rule in the packet according to the method we have proposed. We have to recognize functions of the system and make the list of events first. Then we capture the network packet whenever the event are occurred. The captured packets are examined by means of the method that is finding repeated parts, changed parts according to the input value, fixed parts and changed parts according to regular rules. Finally we make the test program to verify the protocol. We applied this method and procedure to upgrade Electronic Warfare Test System which is operated by ADD. We have briefly described the redesign of control and analysis software for Electronic Warfare Test System
Performance Analysis of Follower Noise Jamming Considering Tracking Parameters against Frequency Hopping Signals
Lee, Chi-Ho ; Jo, Sung-Jin ; Ryu, Jeong-Ho ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 67~75
In this paper, we analyze the performance of Follower Noise Jamming(FNJ) considering three practical tracking parameters such as tracking bandwidth, tracking time and tracking success probability. The performance of FNJ is compared with that of Partial-Band Noise Jamming(PBNJ) in terms of Symbol Error Rate(SER) at the communication receiver under the assumed typical operation model. It is observed that the performance of FNJ is non-linearly dependent on the tracking bandwidth, the tracking time and the tracking success probability. As we can easily expect, it is also observed that the performance of FNJ is better than that of the PBNJ. Finally, it is shown that, for a fixed tracking bandwidth, the combinations of the required tracking time and the tracking success probability which satisfy a certain required SER.
Technical Performance Measurement & Aanaysis Process Implementation Method and Tool Development of The Defense R&D Project
You, Yi-Ju ; Park, Young-Won ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 76~88
The purpose of the research is to propose an earned-value indicator for technical performance measurements of an ongoing defense R&D project and the associated measurement, analysis and the implementation process for data collection and usages. Furthermore, the study demonstrates the evidences of benefits and validity of the proposed approach through the enabling tool development and its application examples.
Vetronics Design Using Realtime Integrated Control Techniques
Lee, Seok-Jae ; Min, Ji-Hong ; Lyou, Joon ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 89~98
The vetronics is necessarily required for enhancement of the operational capability and optimization of the system architecture. In this paper, we presents the realtime control methods for the vetronics of the fighting vehicles. We proposed the data distribution based on standard bus and computer resource for realtime and integrated control of the system. Embedded computers are designed considering extensibility and reliability of the system. The integrated display improves the operator's capability. We applied the network centric battle management and digital power control with intelligent switching elements to increase cooperated combat efficiency and reliability. To show the feasibility of the presented design schemes, the vetronics has been implemented and applied to a real fighting vehicle.
The Effect of Digital Elevation Resolution on LOS Analysis
Eo, Yang-Dam ; Park, Wan-Yong ; Lee, Yong-Woong ; Lee, Byoung-Kil ; Pyeon, Mu-Wook ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 99~105
The analysis of LOS(Line-Of-Sight) is defined as an "unobstructed view between two points". The LOS results may be influenced by terrain source, algorithm/interpolation method, etc. In the area denies any access and flight over, LOS results would be doubtful because of low precision of terrain data therefore have limitations of referring to many military applications. Using LIDAR data, LOS Analysis was performed by changing DTED resolution(1
30m) and LOS distance(50
2000m). The results of experiment shows that LOS analysis for small area, such as DMZ surveillance, were heavily influenced by DTED resolution.
A Study of a Secure Channel Implementation on the Military Computer Network
Lee, Jun ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 106~114
In this paper we suggest a protocol and an algorithm which connect a secure channel between a server and a client over a TCP layer. To make key exchange time the most quickly, the protocol adopts ECC Diffie Hellman(ECCDH) algorithm. And the protocol does not use Hello message for key exchanges and state changes. We also implement this protocol over an open TCP/IP program and check the secure channel connecting time over the military computer network. The suggested protocol could be practically used on the military computer network without a hardware implementation.
Image Steganographic Method using Variable Length for Data Embedding
Jung, Ki-Hyun ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 115~122
Wu and Tsai's pixel-value differencing method and Chang and Tseng's side-match method are based on the theory that the number of bits which can be embedded is determined by the degree of the pixel's smoothness, or its proximity to the edge of the image. If pixels are located in the edge area, they may tolerate larger changes than those in smooth areas. However, both methods are subject to the fall off the boundary problem(FOBP). This study proposes a new scheme that can solve the FOBP. The experimental results demonstrate that the proposed method resolves the problem, and achieves a higher image quality index value than other methods.
Development of Superplastic Forming/Diffusion Bonding Technology for Ti-6Al-4V Sandwich Panels
Lee, Ho-Sung ; Yoon, Jong-Hoon ; Lee, Seung-Chul ; Park, Dong-Kyu ; Yi, Yeong-Moo ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 123~128
Ti-6Al-4V alloy is a critical strategic metal used in aerospace structure due to the high specific strength, toughness, durability, low density, corrosion resistance. Examples of application of this alloy are airframe structural components, aircraft gas turbine disks and blades. Forming of this alloy is not easy due to its high strength and low formability. However, this alloy shows superplastic properties that allow for large plastic deformation under certain conditions. Combination of superplastic forming and diffusion bonding(SPF/DB) processes of this alloy has been widely used to replace mechanically fastened structures with reduced weight and fabrication costs. In this study, superplastic forming/diffusion bonding technology has been developed for fabricating lightweight sandwich panels with Ti-6Al-4V alloy. The experimental results show the forming of titanium lightweight sandwich structure is successfully performed from 3 and 4 sheets of Ti-6Al-4V.
Beam Stabilization Beamforming Technique for Hull-Mounted Sonar Performance Enhancement
Ryu, Young-Woo ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 129~137
Hull-Mounted Sonar(HMS) has been the main equipment to detect and track underwater threats like torpedoes and enemy submarines. The HMS has short warming-up time and is employable independently with sea-state and weather condition. But these bad environmental condition and ship maneuvering make ship's roll and pitch. Ship's roll and pitch make unstability of sensor position, then cause degradation of the HMS performance. In this paper, we will show how the unstability influences the HMS performance, propose the 'Beam Stabilization Beamforming Technique' to overcome these phenomenon. And present the effectiveness of proposed technique by comparing with conventional beamforming result.
Design of Dual-Polarized Waveguide Slot Array Antenna for Synthetic Aperture Radar
Yi, Dong-Woo ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 138~145
In this paper, the waveguide slot array antenna which is capable of wide beam steering and dual polarization is designed for an X band synthetic aperture radar. In order to improve the restriction of beam steering range and to remove the butterfly lobes, a typical waveguide slot array antenna has been modified. To implement dual polarization, rod excited waveguide slot elements and ridge waveguide slot elements are alternately arranged. Location of slots, inclination of rod and offset distance of slots are determined on using array characteristic and conductance constant with radiating power on slots. The designed antenna is manufactured and measured with Near-filed measurement method.
Design of High-Power Switched Filter Bank for Harmonic Suppression
Lee, Byeong-Nam ; Park, Dong-Chul ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 146~153
High-power communication jammer has to include the switched filter bank to eliminate the harmonic signals generated by amplifier. Generally, the switched filter bank consists of in-out switches and several filters. This paper describes the design of high-power switched filter bank, particularly the high-power filter bank operating over 20
110MHz frequency range. The filters designed have insertion loss less than 0.3dB, VSWR less than 1.25:1, and harmonic suppression more than 35dB. Also, the switched filter bank can endure upto 2kW high-power signal with very low harmonic level within
An ab Initio Predictive Study on Solvent Polarity
Park, Min-Kyu ; Cho, Soo-Gyeong ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 154~160
We investigated molecular polarity by using theoretical means and comparing empirical solvent polarity. Our approach employed electrostatic potentials at the molecular surface calculated by density functional methods. A number of molecular descriptors related to molecular polarities were computed from molecular surface electrostatic potentials. Among computed molecular descriptors, the most positive electrostatic potential provided the best correlation with the empirical solvent polarities. A regression equation was developed in order to predict molecular polarities of molecules whose experimental solvent polarities were unknown. The new regression equations were utilized in estimating solvent polarities of cubane derivatives which are considered important precusors of high-energy density meterials.
Dynamic Analysis of a Deployable Space Structure Using Passive Deployment Mechanism
Choi, Young-Jun ; Oh, Hyun-Ung ; Choi, Yong-Hoon ; Lee, Kyung-Joo ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 161~168
The deployable space structure is necessary to minimize the satellite volume and launch cost. For the deployment, passive deployment mechanism has widely been used to attenuate a latch shock induced when the structure is just fully deployed. To reduce the latch shock, viscous damper is applied to the passive deployment mechanism and it can control the deployment speed of the structure. In this paper, dynamic analysis of the deployable space structure using the passive deployment mechanism with the viscous damper has been performed. The viscous damping values have been optimized through numerical simulation. The satellite's attitude influenced by pyro activation for the release of the structure has also been investigated.
Dispersion Modeling of Fine Carbon Fibers in Atmospheric Boundary Layer
Kim, Seog-Cheol ; Hwang, Jun-Sik ; Lee, Sang-Kil ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 3, 2008, Pages 169~175
A fine carbon fibers dispersion model is implemented to calculate the scattering range and ground level concentration of carbon fibers emitted at certain altitudes of atmospheric boundary layer. This carbon fibers dispersion model was composed by coupling a commonly used atmospheric dispersion model and an atmospheric boundary layer model. The atmospheric boundary layer model, applying the Monin-Obukov Similarity Rule obtained from measurement input data at ground level, was used to create the atmospheric boundary layer structure. In the atmospheric dispersion model, the Lagrangian Particle Model and the Markov Process were applied to calculate the trajectory of scattered carbon fibers relative to gravity and aerodynamic force, as well as carbon fibers specification.