• 한국군사과학기술학회지
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• 제12권2호
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• pp.133-138
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• 2009

A mortar system is able to be fired more rapidly and concentratedly than other field gun systems. A mortar system can be easily manufactured because of its simple structure. It has also been supporting for the fire power of infantry because it can be carried conveniently. But a mortar system has demerits that are the limited firing range, poor accuracy and uncomfortable operability. Korean army plan to be operated rapidly and enlarge battle field in the near future. So weapon systems of Korean army must have longer firing range, automatic laying function and precision firing capability. This study suggests efficient developing concept of 120mm self-propelled mortar system through surveying the technical readiness level of current R&D and manufacturing ability.

• 한국군사과학기술학회지
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• 제18권5호
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• pp.492-497
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• 2015

Currently, there are many kinds of tracked armored vehicles in service and they have encountered various environment and situations. So there are many obstacles to operate them improperly such as an engine stall. The causes of engine stall are an insufficient fueling, a mixture of air-fuel or vapor lock, and load increment which results from a rapid steering or increasing a viscosity of lubricant by low temperature. In this paper, engine stall by load increment due to a rapid steering or increasing of lubricant viscosity on tracked armored vehicles is analyzed, the ways to prevent it are applied, and their degrees of improvement are evaluated.

• 한국군사과학기술학회지
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• 제22권6호
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• pp.754-762
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• 2019

The transfer case for special truck are usually produced by only a few specialized companies. The special technical data are not unveiled. In order to complete the development successfully, it is necessary to carry out the compatibility tests such as the running test on the vehicle, which is the test condition of the military vehicle. In this research, transfer case the core-component of the '230 mm K-MLRS' has been developed with the reverse engineering and the prototype is developed through structural analysis. The transfer case developed through this research is currently used in the '230 mm K-MLRS'. The development process In this research are useful in the development of similar products.

• 한국군사과학기술학회지
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• 제18권5호
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• pp.558-565
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• 2015

The current methods, such as Binomial Probability Distribution or T-test, to calculate the number of samples of Precise Guided Missiles(PGMs) for test and evaluation are statistically problematic to make reasonable decisions thus use the budget efficiently. Also, the method to verify an accuracy rate of the PGMs using these old methods seems to be lack of objectiveness. This paper presents an effective, efficient solution adapted from the clinical medicine testing method of healthcare industry research, which may overcome our problems. This method considers and addresses both manufacturers' and consumers' risk simultaneously. By taking into account the weapon system project characteristics which take a relatively longer time and require higher-level budget, this approach also suggests a reasonable and feasible method to determine the amount of samples of the PGMs and making a criterion to verify an accuracy rate of the missiles that are required to test. Thus, this method is expected to contribute to acquisition and operations of high-reliability PGMs by MND and its field-users.

• 안보군사학연구
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• 통권7호
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• pp.91-128
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• 2009

Society is developing fast. Nobody could expect that computer could be used in purpose of trajectory calculation when the ANIAC was developed in the past. However, nowadays technology development brought computerization which substitutes to mankind's working. And personal computer including internet make our society to be IT age. Such age is in revolutionizing now that could be able to bring a new paradigm. We should prepare to such change which scholars predict the end of revolution could be reached at ubiquitous age. This study is purposing firstly for predicting which changes are arisen in the defence sector when social system will become ubiquitous age. That is how change of ubiquitous paradigm could influence to the defence sector and which appearance could be arisen in ubiquitous defence environment. The second purpose of this study is to predict the characteristics of Planing, Programing, Budgeting, Executing, Evaluating, System (PPBEES) of the defence sector.

• 한국군사과학기술학회지
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• 제20권3호
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• pp.315-327
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• 2017

In this paper, we present a method for estimating of position and velocity of a moving target by using the range and the bearing measurements from multiple sensors of aiming unit. In many cases, conventional low cost gyro sensor and a portable laser range finder(LRF) degrade the accuracy of estimation. To enhance these problems, we propose two methods. The first is background image tracking and the other is principal component analysis (PCA). The background tracking is used to assist the low cost gyro censor. And the PCA is used to cope with the problems of a portable LRF. In this paper, we prove that our method is robust with respect to low-frequency, biased and noisy inputs. We also present a comparison between our method and the extended Kalman filter(EKF).

• 한국주조공학회지
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• 제34권6호
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• pp.187-193
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• 2014

In the present work, the effect of adding Ce on the corrosion behavior of Mg-4Al-2Sn-1Ca alloy was investigated. The studied alloys were fabricated by gravity casting method and a potentiodynamic polarization, A.C. impedance and hydrogen evolution tests were carried out in a 3.5% NaCl solution with pH 7.2 at room temperature to measure the corrosion properties of Mg-4Al-2Sn-1Ca-xCe alloys. The microstructure of the Mg-4Al-2Sn-1Ca alloy was composed of ${\alpha}$-Mg, Mg17Al12, Mg2Sn and CaMgSn phase. Also, a $Al_{11}Ce_3$ phase was newly formed by the addition of Ce. With an increase of the Ce contents, the microstructure became refined and the corrosion resistance improved.

• 한국전자파학회논문지
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• 제24권5호
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• pp.558-565
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• 2013

본 논문에서는 고해상도 광대역 영상레이더의 성능을 분석하기 위하여 시간, 주파수 및 Numeric 영역에서 아날로그, RF 및 디지털 신호처리 해석을 통합할 수 있는 시스템 시뮬레이션 툴인 Agilent사의 ADS Ptolemy DF(TSDF: Timed Synchronous DataFlow)를 이용하여 모델링 및 시뮬레이션을 수행하였다. 영상레이더용 하드웨어 시스템은 안테나, 통제장치 및 송수신 장치로 크게 구성되며, 송수신 장치는 고주파 변환 장치, 고출력 송신 장치, 그리고 송수신 전단 장치로 구성된다. 본 논문에서는 시스템의 하드웨어 성능에 영향을 미치는 오차 변수를 정의하고, 이들 오차 변수의 오차 원인이 되는 부품에 대한 특성을 모델링하였다. 영상레이더는 TSDF 모델링 기법을 이용하여 순방향 전송 임펄스 특성($S_{21}$), 고주파 소자의 비선형 특성(이득 비선형, 3차 intercept 및 믹서 교차변조), 채널간 전파 특성, 주파수 합성기 위상 잡음, TWTA의 진폭/위상 특성, 파형 발생기의 샘플링 주파수 및 I/Q 밸런스 등에 대한 모델링을 수행하여 SAR 성능을 분석하였으며, 최종 임펄스 응답 특성 분석을 통한 시스템의 하드웨어 규격을 도출하였다.

• 센서학회지
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• 제31권2호
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• pp.120-124
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• 2022

With advancements in underwater stealth technology for naval vessels, new sensor configurations for detecting targets have been attracting increased attention. Latest underwater mines adopt multiple sensor configurations that include electric field sensors to detect targets and to help acquire accurate ignition time. An underwater electric field sensor consists of a pair of electrodes, signal processing unit, and preamplifier. For detecting underwater electric fields, the preamplifier requires low-noise amplification at ultra-low frequency bands. In this paper, the specific requirements for low-noise preamplifiers are discussed along with the experimental results of various setups of matched transistors and chopper stabilized operational amplifiers. The results showed that noise characteristics at ultra-low frequency bands were affected significantly by the voltage noise density of the chopper amplifier and the number of matched transistors used for differential amplification. The fabricated preamplifier was operated within normal design parameters, which was verified by testing its gain, phase, and linearity.

• 한국고분자학회지:고분자과학과기술
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• 제3권6호
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• pp.455-464
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• 1992