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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 10, Issue 4 - Dec 2007
Volume 10, Issue 3 - Sep 2007
Volume 10, Issue 2 - Jun 2007
Volume 10, Issue 1 - Mar 2007
Selecting the target year
A Study on Heat Flow of Laser-Welded Dissimilar Steel Joints with Gap
Yang, Hae-Sug ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 5~15
A welding structures is generally composed of dissimilar steel materials in order to reduce weight cost, and has a gap to fill the welding agent. Also, heat flow analysis should be fulfilled for structure existing of gap to figure out residual stress which is generated after welding. Since mechanical properties of welding structure composed of dissimilar steel is more fragile than mechanical properties of welding structure consisted of same material, heat flow analysis verifying this should be fulfilled as well. Therefore, on this research, heat flow analysis about dissimilar steel weldment consisted of gap existing AISI304 and AISI630 is practiced so that it could be a basic data of research about mechanical properties of gap existing dissimilar steel welding part which is going to be studied later on. During heat flow analysis, heat input model which based on Gaussian profile and using volume heat flux was newly consisted and applied. In addition, for verifying of analysis on this research, gap existing dissimilar steel weldment which had gap of 0.25mm and was welded using Nd-YAG. The welding profile and temperature distribution for weldment during welding was compared to the result which was gotten through heat flow analysis. Both of those results corresponded each other.
High-frequency Back-scattering Cross Section Analysis of Rotating Targets
Kim, Kook-Hyun ; Cho, Dae-Seung ; Kim, Jin-Hyeong ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 16~24
The high-frequency analysis method of back-scattering cross section spectrum of rotating targets is established. The time history of the back-scattering cross section is calculated using a quasi-stationary approach, based on a physical optics and a physical theory of diffraction, combining an adaptive triangular beam method to consider the shadow effect. And the spectra of back-scattering cross section by the Doppler effect are analyzed applying a simple fast Fourier transform method to its time history. The numerical calculation for rotating targets, such as rotating metal plates and underwater propeller, are carried out. The time history appears to be periodic with respect to the number of wings. The backscattering cross section spectrum level and its frequency shift are dependent on the rotating speed, direction, and the shape of the targets.
Classified Image Enhancement of IRST Based on Loaded Location in Ship and AOS
Kim, Tae-Su ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 25~33
In this paper, I propose a method which can enhance the visual quality of IRST images based on a loaded location in ship and an AOS. The IRST adjusts an AOS to detect targets with various altitudes because of its narrow vertical field of view and offers various functions to enhance images with its low contrast. In the proposed method, images are divided into two regions of sea and sky on the basis of the horizon after establishing relation between an AOS and a horizon location within an image. As a result, image enhancement of the proposed method is performed adaptively according to the divided region while that of conventional method is performed for entire image without the region division. Simulation results show that the proposed method represents higher visibility compared with conventional one.
A Study on Multi Sensor Track Fusion Algorithm for Naval Combat System
Jung, Young-Ran ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 34~42
It is very important for the combat system to process extensive data exactly at short time for the better situation awareness compared with the threats in these days. This paper suggests to add radial velocity on the decision factor of sensor data fusion in the existing algorithm for the accuracy enhancement of the sensor data fusion in the combat system.
Influence of the Geoacoustic Parameters of Seabed Appearing in the Broadband Interference Pattern by Moving Targets
Hahn, Joo-Young ; Lee, Hyeong-Uk ; Lee, Bong-Ki ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 43~50
A range-frequency interference pattern is analyzed in the course of the propagation of ship noise in shallow water. It has been shown to exhibit striated bands of intensity maxima and minima in the spectrogram. The slope of the striations is an invariant of the modal interference and is described by a waveguide invariant parameter
. It turns out that this interference pattern is useful for identifying the physical properties of the waveguide such as seabed properties. In this article, the interference pattern is analyzed using image processing techniques to produce the distribution of the beta and the effects of sediment types and geoacoustic parameters on beta distribution are examined and characterized by moments of the distributions.
Analysis of Requirements for Night Vision Imaging System
Kwon, Jong-Kwang ; Lee, Dae-Yearl ; Kim, Whan-Woo ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 51~61
This paper concerns about the requirement analysis for night vision imaging system(NVIS), whose purpose is to intensify the available nighttime near infrared(IR) radiation sufficiently to be caught by the human eyes on a miniature green phosphor screen. The requirements for NVIS are NVIS radiance(NR), chromaticity, daylight legibility/readability, etc. The NR is a quantitative measure of night vision goggle (NVG) compatibility of a light source as viewed through goggles. The chromaticity is the quality of a color as determined by its purity and dominant wavelength. The daylight legibility/readability is the degree at which words are readable based on appearance and a measure of an instrument's ability to display incremental changes in its output value. In this paper, the requirements of NR, chromaticity, and daylight legibility/readability for Type I and Class B/C NVIS are analyzed. Also the rationale is shown with respect to those requirements.
A Study on Daily Temperature Cycle of Environmental Test in the Korean Peninsula
Lee, Jeong-Yong ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 62~70
Most design temperature of environmental test in korea is based on the standard of Department of Defense. There are few studies to establish temperature standard. Besides the representative environmental test guide 'MIL-STD-810F' encourage to tailor to generate the most relevant test data possible and to test to make a match of test environment with operational environment. Under these circumstances, it is irrational to comply with baseless daily cycle. Thus the study about design method of test temperature is essential. So, the daily cycles to be appropriate to the Korean peninsula was presented in this study. And this research shows how to derive two main element, frequency-of-occurrence and daily maximum (minimum) temperature in daily cycles, in case we can not find the daily cycle.
An Analysis of Multi-path Propagation Characteristics Using DTM : Considering Slope of the Ground Surface
Lim, Joong-Soo ; Chae, Gyoo-Soo ; Kim, Min-Nyun ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 71~78
We suggest a multi-path propagation analysis method using DTM(Digital Terrain Map). Generally, the total signal strength at a target is calculated by adding the field propagated in free space and the field reflected from the ground surface. In this paper, we also consider the vertical reflections associated with the vertical surfaces such as precipitous cliffs and electricity pylons in the mountain area. In addition, we primarily take account the main slope of the ground surface to improve the accuracy of the total field density at the target.
A Study on the Application of Analytic Hierarchy Process to Improve the Fairness of Evaluation Indicators for the National Defense Core Technology R&D Projects
Kim, Chan-Soo ; Cho, Kyu-Kab ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 79~89
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.
Improving Adaptability of the DEVS Based Simulator with AOP
Kim, Cheol-Ho ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 90~99
The DEVS formalism has the well-defined relationship between its model and simulator. However, it does not define the connection between its model and experimental frame needed when a simulator's implemented with it. So, in most DEVS based simulators, the modules of the two parts are tangled, so that changing and reusing them is not easy. This paper proposes a method to improve the changeability of the experimental frame and the reusability of the model by modularizing the two parts using the AOP technology. I applied the new method to a real project, and the result shows that it improves the two qualities effectively than before.
Integrated Planning Process Implementation Method Based on the Cost, Schedule, and Technical Performance
You, Yi-Ju ; Park, Young-Won ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 100~108
The purpose of the research is to propose an integrated project planning process and its implementation method. Although there is increasing interest in the application of the Earned Value Management(EVM) method in the project management area, the progress and maturity of the technical performance have not been included in assessing the Earned Value. The main concept of the planning process is to use cost, schedule, as well as the technical performance in the assessment of the Earned Value Management for Military R&D project management practices. The resulting process can enhance the efficiency of the project work by eliminating the currently duplicated activities between traditional project planning process and the newly implemented Earned Value Management process and by shortening the early planning process duration of projects adopting EVM practices.
Laser Welding for Wing of a Guided Weapon
Suh, Jeong ; Lee, Jae-Hoon ; Kim, Jeng-O ; Chung, Koon-Seok ; Jeong, Hae-Yong ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 109~113
Laser welding process for wing of a guided weapon is studied. Nd;YAG pulse laser beam is used to weld the skin(STS304, thickness: 1mm) to frame(AMS 5398) of wing. Optimal laser welding condition is obtained from the mechanical testing and observation of the welded joint.
High Temperature Dielectric Properties of Silicon Nitride Materials
Choi, Doo-Hyun ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 114~119
Dielectric properties of quartz glass and
are investigated using the waveguide method from room temperature to
. For the case of dielectric constant,
showed similar increase with quartz glass up to
, but less increase from
. For the case of loss tangent, those showed gradual increase with temperature except of some temperature points. The loss tangent of
and quartz glass increased up to 18.2% and 12.5% respectively. Through these researches, high temperature dielectric properties of silicon nitride materials are characterized.
Fabrication of a Large Object by Rapid Prototyping Technics
Choi, Hong-Seok ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 120~128
In order to reduce the lead-time and cost, the technology of rapid prototyping(RP) has been widely used. This paper describes the methodology to fabricate a large object by using the principle of rapid prototyping. By laminating thick and sloping polystyrene foam plates, we can make the large model which has three dimensional, continuous surfaces faster and easier than conventional processes. Estimated error was much smaller than other RP products which have stepped effect. For accuracy improvement and post processing, machined metal plates are added between the thick plates. To keep the continuity of surface and strengthen the model, pilot holes and guide rods are applied. By the methodology described in this paper, a missile body with flush air intake was fabricated.
The Performance Analysis of Burst Error Elimination CVDF Algorithm Using Switching Remote Direction Finding Antenna in VHF
Won, Jong-Mook ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 129~138
Recently, Direction Finding(DF) System is using switching DF algorithm to reduce system-weight by eliminating RF cable as much as possible. Also, Correlation Vector Direction Finding(CVDF) algorithms is being used for Fast Direction finding in tactical environment. In this paper, I will give you burst error elimination algorithms and compare the performance in case we use switching CVDF algorithm. Although antenna array is not working, we will successfully perform direction finding when we use this burst error elimination algorithms. Also, we will be completely capable of DF mission despite of meeting the unwanted situation that the monitoring signal disappear in case we use Switching Direction Finding algorithms. That situation frequently occurs under the Frequency Hopping signal circumstances.
Development of Lane and Vehicle Headway Direction Recognition System for Military Heavy Equipment's Safe Transport - Based on Kalman Filter and Neural Network -
Choi, Yeong-Yoon ; Choi, Kwang-Mo ; Moon, Ho-Seok ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 139~147
In military transportation, the use of wide trailer for transporting the large and heavy weight equipments such as tank, armoured vehicle, and mobile gunnery is quite common. So, the vulnerability of causing traffic accidents for these wide military trailer to bump or collide with another car in adjacent lane is very high due to its broad width in excess of its own lane's width. Also, the possibility of these strayed accidents can be increased especially by the careless driver. In this paper, the recognition system of lane and vehicle headway direction is developed to detect the possible collision and warn the driver to prevent the fatal accident. In the system development, Kalman filtering is used first to extract the border of driving lane from the video images supplied by the CCD camera attached to the vehicle and the driving lane detection is completed with regression analysis. Next, the vehicle headway direction is recognized by using neural network scheme with the extracted parameters of the detected driving lane feature. The practical experiments for the developed system are also carried out in the real traffic road of Seoul city area and the results show us the more than 90% accuracy in recognizing the driving lane and vehicle headway direction.
Scattering Analysis of Radar Target via Evolutionary Adaptive Wavelet Transform
Choi, In-Sik ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 148~153
In this paper, the evolutionary adaptive wavelet transform(EAWT) is applied to the scattering analysis of radar target. EAWT algorithm uses evolutionary programming for the time-frequency parameter extraction instead of FFT and the bisection search method used in the conventional adaptive wavelet transform(AWT). Therefore, the EAWT has a better performance than the conventional AWT. In the simulation using wire target(Airbus-like), the comparisons with the conventional AWT are presented to show the superiority of the EAWT algorithm in the analysis of scattering phenomenology. The EAWT can be effectively applied to the radar target recognition.
Design and Performance Analysis of Direction Finding System Test-bed for Communication-band Signals
Choi, Jun-Ho ; Park, Young-Mi ; Yang, Jong-Won ; Nah, Sun-Phil ; Park, Cheol-Sun ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 154~160
A direction finding system test-bed(DFSTB) at the electronic warfare communication-band is presented to efficiently evaluate and optimize the performance of the direction finding system through the indoor test setup. This test-bed gives a significant benefit to the designers of the direction finding system because it allows flexible test and design trade-off in the system design cycle. The system description and implementation of test-bed architecture, and the experiment results of direction finding accuracy according to modulation schemes are presented.
Kinematics and Robust PID Trajectory Tracking Control of Parallel Motion Simulator
Hong, Seong-Il ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 161~172
This article suggests an inverse kinematics analysis of a two degree of freedom spatial parallel motion simulator and design methodology of the robust PID controller. The parallel motion simulator consists of a fixed base and a moving frame connected by two serial chains, with each serial chain containing one revolute joint and two passive spherical joint. First, an inverse kinematics problems are solved in order to find the joint variable necessary to bring the end effector to track the desired trajectory. Second, an inverse optimal PID controller is proposed to track trajectories in the face of uncertainty. And the
optimality and robust stability of the closed-loop system is acquired through the PID controller. Finally numerical results show the effectiveness of the PID controller that is designed by square/linear tuning laws.
Separation Mode Analysis of Track Assembly of Main Battle Tank
Lee, Kyoung-Ho ; Park, Byoung-Hoon ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 173~180
In this paper, we have proposed a simple finite element model for separation mode analysis on the roadwheel and track assembly of main battle tank and established a contact stress-based mechanism which could explain the initiation and growth of separation defect occurred during the test of padreplacable track. It was proved that the longitudinal contact shear stress component on the pin hole region of the track shoe body which is parallel to the driving direction is consistent with the crack initiation at the bonding surface between track shoe and wheel-side rubber. The longitudinal shear stress increased locally near the separated region after the separation initiated. So we could assume that the local stress concentration accelerates the separation growth according to the shear mode.
A Study on the Torque Control Method of a Hydraulic Actuation System for Measuring the Dynamic Stiffness of Missile Fin Actuators
Lee, Ho-Sung ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 181~188
This paper presents a torque control method of a hydraulic actuation system for measuring the dynamic stiffness of missile fin actuators. We propose a new control technique called Dual Dynamic Torque Feedback Control(DDTFC), which improves the stability of the torque control system and enables fast tracking of torque command. The developed control scheme is derived from the physical understanding based on mathematical modelling and analysis. The dynamics of hydraulic torque control servo-system is unravelled via physics-based modelling and nonparametric system identification. In order to verify the effectiveness of the method, the experiment is carried out with a test equipment for measuring the dynamic stiffness. The experiment and simulation results show that DDTFC gives stability improvement.
Swimming Mechanics of Aquatic-Animals
Sohn, Myong-Hwan ; Han, Cheol-Heui ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 189~199
The present survey paper introduces the research history, characteristics of body and fin shapes, basic principles of various locomotions and propulsion-generation mechanism of aquatic animals in nature, which utilize unsteady flow through a noble mechanism that is different in paradigm from the propulsion generation mechanism of man-made marine vehicles, and so have excellent performance and efficiency. The authors hope that the present paper helps to activate the domestic research interest on the fields of swimming in nature, which is expected to provide great ideas for improvement and innovation of today's marine vehicles.
Research on the Storage Life of Single Base Propellant by Adding Inorganic Stabilizer
Chang, Il-Ho ; Cho, Ki-Hong ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 200~207
Single base propellant using a nitrate ester compound NC decomposes naturally during storage time. Therefore, the research for storage life extension is necessary to single base propellant. In this research,
inorganic stabilizer had been added into single base propellants up to 0.3%, and the accelerated aging test of the propellant was started. And then, with applying the Arrhenius equation, the storage life of the test of the propellant was contrasted with that of reference propellant. As a result, the storage life of the propellant containing
inorganic stabilizer was about twice longer than the reference propellant.
A Study on the Pressure-travel Curve of 5.56mm Rifle Obtained from the Empirical Base Pressure Factor
Lee, Sang-Kil ; Lee, Gang-Young ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 208~216
As the propellant mass is being accelerated out of the gun chamber along with the projectile, a continuous pressure gradient exists between the end of chamber and the base of the projectile. For this reason, the base pressure-travel curve is very important to design a conventional gun barrel in the interior ballistics, but it is not obtained briefly by empirical or theoretical method. In this paper, a simple relation between chamber pressure and base pressure was determined by the factor of base pressure(Cb) obtained from the experimental method. The simple relation gives a reasonable prediction for the reduction of pressure between the breech and the base of projectile owing to the axial gradient in the gun tube. The predictions have been validated by the infrared screen sensor and the PRODAS(PROjectile Design and Analysis System) for interior ballistic systems. Therefore, the base pressure-travel curve could be calculated from the chamber pressure measured by piezoelectric sensor. The base pressure-travel curve obtained from the simple relation offers initial information to gun barrel designer and is used for calculation of muzzle velocity.
An Evaluation of Silencer Characteristics by Live Firing Test
Kang, Kuk-Jeong ; Ko, Sung-Ho ; Kwak, Young-Kyun ; Lee, Duck-Joo ; Lee, In-Cheol ;
Journal of the Korea Institute of Military Science and Technology, volume 10, issue 3, 2007, Pages 217~224
The present work addresses an experimental study on sound attenuation characteristics of silencer by live firing test. When a gun fires, there exists excessive noise which propagates as a form of blast wave. As muzzle energy of the weapon systems increases, the level of impulsive noise also increases. It is well known that the impulsive noise from a gun gives a serious damage to human bodies and structures. The adverse effects of impulsive sound also cause both social and military problems. So it is very important to study the characteristics of the impulsive sound attenuation. The live firing test is performed to evaluate the effect of four different silencers. The test result is compared with the case of bare muzzle which is not installed the silencer. The frequency characteristics are also analyzed to investigate the diminution of sound pressure level. The results of this study will be helpful to the designing silencer for large caliber weapon systems.