• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.35 no.1
• /
• pp.1-8
• /
• 2022

This study proposes a penetration model in soil considering the wake separation and reattachment based on the integrated force law (IFL). Rigid body dynamics, the IFL, and semi-empirical resistance function about soil are utilized to formulate the motion of the hard projectile. The model can predict the trajectory in soil considering the spherical cavity expansion phenomenon under various oblique angles and angles of attack (AOA). The Mohr-Coulomb yield model is utilized as the resistance function of the soil. To confirm the feasibility of the proposed model, a comparative study is conducted with experimental results described in the open literature. From the comparative study, the penetration depth estimated from the proposed model had about 13.4% error compared to that of the experimental results. In general, the finite element method is widely used to predict the trajectory in soil for a projectile. However, it takes considerable time to construct the computational model for the projectile and perform the numerical simulation. The proposed model only needs to the dimension of the projectile and can predict the trajectory of the projectile in a few seconds.

• 시스템엔지니어링워크숍
• /
• s.4
• /
• pp.123-134
• /
• 2004

This paper deals with the feasibility analysis and alternatives for infrared detector development. The purpose of this paper analyze development requirement and feasibility study in both technology and cost. We get raw input data for system engineering process from development and technical expert, and then analyze cost and technology for development feasibility, and alternative study. Infrared Detector is core component of Thermal Imaging System and developed by ADD from 2006 to 2008 year. Technical level is analyzed by TRL(Technical Readiness Level) and AOA(Analysis of Alternative) is done by development and production cost estimate. We use SEER-H tool for cost estimate, that is parametric cost estimate tool based on Knowledge Base. Also this paper presents risk analysis for project management because it is necessary to risk driver management during the infrared detector development. The result of IR Detector feasibility and alternative study will be used in technical and cost analysis. This study can help those who are related to the cost analysis and development feasibility of other weapons

• Journal of the military operations research society of Korea
• /
• v.36 no.3
• /
• pp.1-13
• /
• 2010

DEA method has been widely applied on civilian and defense side for efficiency analysis of organizations and programs(project). For many years Defense Industry, military hospital and military construction parts have been analyzed by using DEA method. In this paper we review and propose a method of warship evaluation through DEA method. The evaluation method proposed above can provide plenty of proper information for ROC decision, AOA and source selection on weapon acquisition.

• 한국정보통신설비학회:학술대회논문집
• /
• 2007.08a
• /
• pp.185-190
• /
• 2007

This article describes a development CDMA LBS in order to apply to "Control System of Underground Infrastructure Fire Accident" which one of U-City Projects of Seoul City. Our goal guides taking shelter of the sufferer it will not be able to use a GPS when the fire occurs from subway station. There are Location measurement methods which measures the AOA(Angle of Arrival) of the signal which it sends with the MS(Mobile station) from the BS(Base station), an electronic delivery time (TOA:Time of Arrival) and the relative difference of electronic arrival time from Base stations (TDOA:Time Difference of Arrival). This time the error due to a multiplex course error and near-far problem and NLOS(Non Line of Sight). We are planning to construct the Test Bed which is an error below 1 meter.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.16 no.3
• /
• pp.398-404
• /
• 2013

The simulation of the ballistic trajectory of penetrator into the spaced multi-layer RC targets is very important to predict the hitting condition in subsequent target. Because of perturbation by lateral load of penetrator caused by asymmetric hitting position between penetrator and steel bar reinforcement, penetrator rotates and deviates from the straight path. Therefore, penetration capability of penetrator is decreased in the subsequent targets. This paper presents the result of the penetration of steel-bar-reinforced concrete target by using the explicit finite element code LS-DYNA. A series of computations is performed and compared to experimental data and the computed results are in good agreement with the experimental results over a wide range of velocities. And then we conduct the simulation according to various RC target hitting condition and impact velocities.

• Journal of Plant Biology
• /
• v.33 no.2
• /
• pp.87-96
• /
• 1990

The role of S-adenosylmethionine (SAM) as an intermediate in interrelation between polyamine and ethylene biosynthesis was studied in suspension cultures of Nicotiana tabacum L. Exogenous SAM stimulated the polyamine and ethylene biosynthesis in 4 day-cultured cells, which were in active cell divisions, and 10 day cultured cells, which went on with active cell elongation and senescence. SAM-induced ethylene production was more effective in 10 day-cultured cells than in 4 day-cultured cells, but SAM-induced polyamine biosynthesis was more effective in 4 day-cultured cells than in 10 day-cultured cells. Polyamine contents were increased by the blockage of ethylene biosynthetic pathway in the conversion of SAM to ethylene via 1-aminocyclopropane-1-carboxylinc acid (ACC) with aminooxyacetic acid (AOA). Also, ethylene production was increased by the inhibitors of polyamine biosynthesis such as methylglyoxal bis-(guanylhydrazone) (MGBG), dicyclohexylamine (DCHA), $\alpha$-difluoromethylarginine (DFMA) and $\alpha$-difluoromethylorinithine (DFMO). These results suggest that there may be interrelations between polyamine and ethylene biosynthesis for the competition of SAM and the inherent mechanism of switch on-off in polyamine and ethylene biosynthetic activity with the progress of cell growth and senescence.

• Proceedings of the KIEE Conference
• /
• 2001.11c
• /
• pp.394-397
• /
• 2001

There are several methods of measuring position. For example GPS, AOA, TDOA and using radio camera. In this Paper I used TDOA method in position measuring system. TDOA method uses arrival time difference. In position measuring system, three transfers which is placed in different position transfer signal to receiver in fixed time interval and receiver records arrival time of signal. Because receiver knows idle signal's arrival time, receiver can calculate the difference of the signal's arrival time between idle and real. When we obtain time difference we can know the receiver position by Newton Raphson method.

• Proceedings of the IEEK Conference
• /
• 1999.11a
• /
• pp.27-30
• /
• 1999

A spatio-temporal vector channel model is introduced for the position location (PL) estimation problem for CDMA cellular system environment. Two common ways for the PL make use of the AOA (Angle Of Arrival) and TDOA (Time Difference Of Arrival) from a subscriber to the multiple sensors (base stations). In this paper, we applied the derived vector channel to simulate the multipath channel for the angle of the signal arrival in CDMA systems. Cross-correlation method is a good candidate among other direction finding algorithms available in literature, especially in wideband modulation as in the CDMA system. The PL estimation errors are evaluated for different channels, which are obtained as a parameter of scattering radius of the suggested model. We noted that the number of sensors (base-stations) are related to the PL errors in favor of the available data.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.9 no.1 s.24
• /
• pp.33-40
• /
• 2006

A compact broadband active composite dipole antenna for direction finding system at the V/UHF-band is presented. It uses the composite structure which improves the antenna gain and the active circuit for broadband operation. This type of antenna has a high gain more than that of one dipole antenna within limited length(1m). The basic design and performance of both antenna structure and integrated active circuit are presented.

• Journal of the Korean Society of Systems Engineering
• /
• v.1 no.1
• /
• pp.1-13
• /
• 2005

The purpose of this paper analyze development feasibility and alternatives for infrared detector development in both technology and cost. Infrared Detector is core component of Thermal Imaging System and developed by ADD from 2006 10 2008 year. We got raw input data from development and technical expert, and then analyze cost and technology for development feasibility, and alternatives study. Technology level is analyzed by TRL(Technology Readiness Level) and AOA(Analysis of Alternatives) is done by development cost estimate. Estimating the development cost, we use SEER-H that is parametric cost estimating tool based on Knowledge Base. This study can help those who are related to the cost and development feasibility analysis of other weapon systems.