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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 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
A Study on Configuration Design of the 2D Course Correction Munition
Kim, Ki-Pyo ; Chung, Myung-Jee ; Hong, Jong-Tai ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 5~12
There are some ways to improve precision of conventional munitions by low-cost method. 2D Course Correction Munition(CCM) is one of those ways, which is a 155mm projectile integrated with 2D Guidance Fuze(GF) instead of conventional fuze. 2D GF can correct the projectile trajectory and minimize range and deflection errors from its aimpoint using canard control. In this paper 2D CCM system concept is introduced and its course correction capability is analyzed using PRODAS.
Dynamic Characteristics of a Soft Recoil System
Bae, Jae-Sung ; Shin, Chul-Bong ; Hwang, Jai-Hyuk ; Kang, Kuk-Jeong ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 13~19
In order to reduce the level of recoil force, new recoil technology must be employed. The present study discusses a soft-recoil system that can reduce dramatically the recoil force. The firing sequence of the soft recoil system is radically different from that of a conventional system. The gun is latched and preloaded in its out-of-battery position prior to firing. When unlatched, the gun is accelerated and forward momentum is imparted to the recoiling parts. This momentum is opposed by the ballistic force imparted by firing and the recoil force and stoke will be reduced. In the present study, the soft-recoil system with hydraulic dampers is simulated and its characteristics are investigated theoretically. The results of the simulation show that the soft-recoil system could dramatically reduce the recoil force and the recoil stroke compared to the conventional recoil systems. However, the soft-recoil system was not able to perform well when the firing fault modes like prefire, hang-fire, and misfire happen. Hence, we need to employ a control algorithm to prevent the damage of the recoil system due to these fault mode.
Aerodynamic Heating Analysis of Supersonic Missile Body and Fin
Kang, Kyoung-Tai ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 20~28
Missile operating at supersonic conditions experiences considerable high temperature environments that is caused by aerodynamic heating as a result of the temperature gradient through boundary layer that surrounds it. This is one of important problems to the designer due to temperature limitation of structural materials. Because prediction of aerodynamic heating on missile needs unsteady calculation according to a flight trajectory, approximate method approach is efficient at design stage. In this paper, improved aerodynamic heating analysis scheme is introduced, which calculates heat flow and temperature by simple pressure field prediction on a missile body and fin. The prediction results are compared with measured data and MINIVER codes results.
Homing Guidance Law for Alleviating Sensitivity to Initial Heading Errors
Lee, Jin-Ik ; Jeon, In-Soo ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 29~35
In this paper, a new guidance law to reduce sensitivity to the initial heading errors is proposed. In order for shaping the input weights over the flight, we introduce the distribution functions expressed in terms of time-to-go and its inverse term. By applying the optimal control theory with the synthesized weights, the homing guidance law is derived. Also the characteristics of the proposed law are examined. Various computer simulations show the good performance of the proposed guidance.
Digital Receiver for Analysing Radar Intrapulse Modulation Signal
Lee, Young-Joong ; Kim, In-Sun ; Park, Ju-Rae ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 36~45
LYNX ESM system operates digital receiver for analyzing radar of intrapulse modulation signal. This paper contains DC offset compensation method of IQ channels, imbalancing comensation method of amplitude and phase, precisional PW measurement using adaptive threshold set, analyzing algorithm of intrapulse modulation signals. Its effectiveness was proven by technical and operational test.
A Study on Hybrid Discovery Mechanism for Large-Scale Realtime Distributed Systems
Jung, Yong-Hwan ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 46~58
Naval combat management system is a kind of complex weapon systems performing naval ship's warfare mission by integrating various types of system including sensor systems, weapon systems and many kinds of communication system. Recently, there are many studies to apply commercial high-level communication middleware to naval combat system development to integrate and interoperate various kinds of heterogeneous on-board systems efficiently. An initial discovery mechanism is required for application modules to start communication with their relevant modules to apply middlware technology in developing naval combat system, which is characterized by large-scale, complex and real-time system. This paper suggests a fast hybrid discovery mechanism which combines static and dynamic discovery mechanism and confirms its adaptability by an experiment on testing environment.
A Study on Efficiency Improvement for SUGV with a Practical View Point of Non-Functional Requirements
Seo, Jin-Won ; Kim, R. Young-Chul ; Kim, Jang-Han ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 59~67
In the next near future, the human would like to use the small unmanned ground vehicle(SUGV) on the diverse fields. Specially the world of today is tried to apply with operating the task on very difficult working environments such as some dangerous or unreachable area. To work this task, this vehicle should be guaranteed with the high level of reliability, safety, and performance. In this paper, we propose to focus on not only the functional requirements, but also the non-functional requirements based on software architecture at the design stage for developing the embedded system. Through focusing on the non-functional requirements on this software architecture, we can obtain the design goal of the target system and also show the enhancement of reliability, safety and performance with 'Vtune' performance analysis tool.
A Data Hiding Method of Binary Images Using Pixel-value Weighting
Jung, Ki-Hyun ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 68~75
This paper proposes a new data hiding method for binary images using the weighting value of pixel-value differencing. The binary cover image is partitioned into non-overlapping sub-blocks and find the most suitable position to embed a secret bit for each sub-block. The proposed method calculates the weighted value for a sub-block to pivot a pixel to be changed. This improves the image quality of the stego-image. The experimental results show that the proposed method achieves a good visual quality and high capacity.
Development of Alloy 718 Nozzle for Ramjet Propulsion Component
Park, Nho-Kwang ; Kim, Jeoung-Han ; Kim, Nam-Yong ; Lee, Chae-Hoon ; Yeom, Jong-Taek ; Hong, Jae-Keun ; Baek, Dong-Kyu ; Choi, Sung-Gyu ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 76~82
Alloy 718 nozzle component was manufactured by hot forging and electron beam welding process. In this process, 718 billets produced in domestic company were used and evaluated. Before performing industrial scale hot forging, small size hot compression tests were carried out under various process conditions and then microstructural evaluations were analyzed. Using the results, FEM simulations were performed in order to optimize the hot working process. After hot working, forged work-pieces were machined and welded by electron beam. Final nozzle components were heat treated and their microstructure and mechanical properties were investigated.
A Study on the Hybrid-ECAP Process to Produce Ultra-Fine Materials
Lee, Ju-Hyun ; Lee, Jin-Ho ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 83~91
The development of the equal channel angular pressing(ECAP) process in metals has recently provided a feasible solution to produce ultra-fine or nano-grained bulk materials with tailored material properties. However, ECAP process is difficult to scale up commercially due to requirements of an excessive load. In this paper, a new Hybrid-ECAP process with torsional die is considered to obtain materials of ultra-fine grain structure under low forming load. An upper bound analysis and numerical simulation (DEFORM 3D, a commercial FEM code) are carried out on the torsional die. By the upper bound analysis, analytical expression for the compression force and rotation speed are obtained. By the FEM analysis, the distribution of strain, stress and deformation are obtained. These results show that the Hybrid-ECAP is a useful process because this process can obtain the homogeneous deformations with relatively low forming load. Additionally, due to decreased forming load, die life can be improve.
The Development of a Beam Steering System for X-band 2-D Phased Array Antenna
Kim, Doo-Soo ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 92~98
A beam steering system of X-band 2-D phased array antenna for radar application is developed. The beam steering system consists of real-time command generator, beam steering unit, control PCB of array module and power supply. It plays a role of beam steering and on-line check of phased array antenna. The performance of beam steering system is verified with pulse timing of current control in phase shifters and measurement of far-field of phased array antenna. The developed beam steering system offers basic technology to develop full-scale beam steering system of multi-function radar.
A Technique for Measuring Terrain Uniqueness from Digital Terrain Elevation Data
Kim, Su-Hwan ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 99~106
Digital Terrain Elevation Data is a set of numerical values that represent the heights of the terrain surface. Terrain has several properties. Among them, roughness is the most widely used one because it gives very useful information to land-based or land-reference platform. There are several ways to measure roughness of terrain. But each of them has own flaws. Moreover, it is not enough to represent the uniqueness of the terrain only by the roughness. We need another metric to measure the actual uniqueness. In this paper, we propose an improved method to measure essential characteristics, uniqueness, of terrain. It gives not only the roughness but also the unevenness. The combination of them makes up the uniqueness. And it can be applied even if there is no pre-planned path on the terrain.
Enhanced Extraction of Traversable Region by Combining Scene Clustering with 3D World Modeling based on CCD/IR Image
Kim, Jun ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 107~115
Accurate extraction of traversable region is a critical issue for autonomous navigation of unmanned ground vehicle(UGV). This paper introduces enhanced extraction of traversable region by combining scene clustering with 3D world modeling using CCD(Charge-Coupled Device)/IR(Infra Red) image. Scene clustering is developed with K-means algorithm based on CCD and IR image. 3D world modeling is developed by fusing CCD and IR stereo image. Enhanced extraction of traversable regions is obtained by combining feature of extraction with a clustering method and a geometric characteristic of terrain derived by 3D world modeling.
A Study on the Measurement Time-Delay Estimation of Tightly-Coupled GPS/INS system
Lee, Youn-Seon ; Lee, Sang-Jeong ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 116~123
In this paper we study the performance of the measurement time-delay estimation of tightly-coupled GPS/INS(Global positioning system/Inertial Navigation system) system. Generally, the heading error estimation performance of loosely-coupled GPS/INS system using GPS's Navigation Solution is poor. In the case of tightly-coupled GPS/INS system using pseudo-range and pseudo-range rate, the heading error estimation performance is better. However, the time-delay error on the measurement(pseudo-range rate) make the heading error estimation performance degraded. So that, we propose the time-delay model on the measurement and compose the time-delay estimator. And we confirm that the heading error estimation performance in the case of measurement time-delay existence is similar with the case of no-delay by Monte-Carlo simulation.
IIR Target Initiation and Tracking using the HPDAF with Feature Information
Jung, Yun-Sik ; Song, Taek-Lyul ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 124~132
In this paper, a dynamical filter called the Highest Probability Data Association Filter(HPDAF) improved by adding target feature information is proposed for robust target detection and tracking in clutter. IIR contains 2-dimensional kinematic coordinate, intensity, and feature information. In data association of the HPDAF for track initiation, feature information is utilized in addition to coordinate and intensity information. The performance of the proposed HPDA algorithm is tested and compared with the conventional HPDAF algorithm for track initiation by a series of Monte Carlo simulation runs for a 3-dimensional missile-target engagement. scenario.
A Study on the Chemical Warfare Agents Dispersion Modelling in a Naturally Ventilated Indoor System
Kye, Young-Sik ; Chung, Woo-Young ; Kim, Yong-Joon ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 133~140
The purpose of this study is to provide response methods to minimize the damage from chemical terrorism in a naturally ventilated indoor system using several types of dispersion simulations. Three chemical warfare agents such as sarin(GB), phosgene and chlorine gas which have high potential to be used in terror or to be involved with accidents were selected in this simulation. Fire dynamic simulation based on Large Eddy Simulation which is effective because of less computational effort and detailed expression of the dispersion flow was adopted to describe the dispersion behavior of these agents. When the vent speed is 0.005m/s, the heights of 0.1 agent mass fraction are 0.9m for sarin, 1.0m for phosgene and 1.1m for chlorine gas, and the maximum mass fraction are 0.27 for all three agents. However, when the vent speed is increased to 0.05m/s, the heights of 0.1 agent mass fraction become 1.6m for all three agents and maximum mass fraction inside the room increase to 0.70 for sarin, 0.58 for phosgene and 0.53 for chlorine gas. It is shown that molecular weight of the agents has an important role for dispersion, and it is important to install ventilation system with height less than 1.6m to minimize the damage from chemical toxicity.
Full Dynamic Model in the Loop Simulation for Path Tracking Control of a 6
6 Mobile Robot
Huh, Jin-Wook ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 141~148
In this paper, we develop a detailed full dynamic model which includes various rough terrains for 6-wheel skid-steering mobile robot based on the real experimental autonomous vehicle called Dog-Horse Robot. We also design a co-simulation for performance comparison of path tracking algorithms. The control architecture in the co-simulation can be divided into two levels. The high level control is the closed-loop control of path tracking to follow a given path, and the low level is concerned about torque control of wheel motion. The simulation using the mechanical data of the Dog-Horse Robot is performed under the Matlab/Simulink environment. We also simulate and evaluate the performance of the model based adaptive controller.
Strength Estimation of T-joint Area of Composite Housing of Medium Range Surveillance Radar
Kwon, Min-Sang ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 149~158
This article provides strength estimation of T-joint area which made of composite material. Inner and outer structures of medium range surveillance radar are all made of sandwich structure which is made with composite material(CFRP) and aluminum honeycomb core. Since the radar is voluminous and has very complex inner structure, the whole structure cannot be made as one piece. Therefore, usage of T-joints is inevitable. Since some of stress concentration areas were located around T-joint area, series of strength estimations were conducted. Three different configurations were tested to improve mechanical properties(primarily on strength). The results show an improvement on strength to meet calculated strength on stress concentrated T-joint area.
Nonlinear Aeroelastic Analysis in Time Domain for Folded Fins using ZAERO
Lee, Dong-Min ; Kim, Jung-Young ;
Journal of the Korea Institute of Military Science and Technology, volume 11, issue 4, 2008, Pages 159~165
The purpose of this paper is to study the impact of concentrated nonlinearities, freeplays, on the aeroelastic behaviors of single- and double-folded control fins. The nonlinearities may cause limit cycle oscillation(LCO) below the linear flutter boundary. The effects of nonlinear hinges on LCO characteristics of the fins are examined as flight condition changes. Nonlinear time-domain flutter analyses are performed, using ZAERO. The results show that the aeroelastic stability boundaries of double-folded fin(DF) are higher than those of the single-folded fin(SF) and the lower hinge freeplay impact more critically on the stability than the upper hinge freeplay of the DF.