• Journal of Korean Society on Water Environment
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• v.28 no.3
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• pp.460-466
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• 2012

Perchlorate is used in a number of applications as an oxidizer in solid propellants, munitions and fireworks and is one of the endocrine disrupting chemicals, which interferes with iodide uptake into the thyroid gland. The purpose of this study was to investigate perchlorate occurrence and distribution with a results of analysis of 94 samples collected from military facilities in Korea from October 11 to October 23, 2011. Overall, among all of the 94 samples analyzed, perchlorate was detected in 6.4% of the total number of samples above $4{\mu}g/L$ (minimum reported limit) and the average concentration was $26.1{\mu}g/L$ and the maximum concentration was $107.7{\mu}g/L$ which was observed in surface water near manufacturing site of ammunition. By site classification, perchlorate was detected at one site in 4 manufacturing sites of ammunition and the maximum concentration was $107.7{\mu}g/L$ which was six times higher than that in guideline for perchlorate in Nakdong River and resulted from point source discharge. Perchlorate was detected at 3 sites in 78 measurements for shooting area and the maximum concentration was $12.4{\mu}g/L$ which was collected in dringking water and perchlorate in another sample was detected above MRL in shooting area was collected right away after shooting. These results showed that long term monitoring was needed considering weather conditions and shooting schedules.

• KIISE Transactions on Computing Practices
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• v.21 no.3
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• pp.247-256
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• 2015

Since the Gulf War, air power has played a key role. However, the effect of high-tech weapons, such as laser-guided bombs and electronic optical equipment, drops significantly if they do not match the weather conditions. So, aircraft that are assigned to carry laser-guided bombs must replace these munitions during bad weather conditions. But, there are no objective criteria for when weapons should be replaced. Therefore, in this paper, we propose an algorithm to predict the hit rate of laser-guided bombs using cloud image processing. In order to verify the accuracy of the algorithm, we applied the weather conditions that may affect laser-guided bombs to simulated flight equipment and executed simulated weapon release, then collected and analyzed data. Cloud images appropriate to the weather conditions were developed, and applied to the algorithm. We confirmed that the algorithm can accurately predict the hit rate of laser-guided bombs in most weather conditions.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.4
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• pp.96-104
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• 2017

A one-shot system (device) refers to a system that is stored for a long period of time and is then disposed of after a single mission because it is accompanied by a chemical reaction or physical destruction when it operates, such as shells, munitions in a defense weapon system and automobile airbags. Because these systems are primarily related with safety and life, it is required to maintain a high level of storage reliability. Storage reliability is the probability that the system will operate at a particular point in time after storage. Since the stored one-shot system can be confirmed only through inspection, periodic inspection and maintenance should be performed to maintain a high level of storage reliability. Since the one-shot system is characterized by a large loss in the event of a failure, it is necessary to determine an appropriate inspection period to maintain the storage reliability above the reliability goal. In this study, we propose an optimal inspection policy that minimizes the total cost while exceeding the reliability goal that the storage reliability is set in advance for the one-shot system in which periodic inspections are performed. We assume that the failure time is the Weibull distribution. And the cost model is presented considering the existing storage reliability model by Martinez and Kim et al. The cost components to be included in the cost model are the cost of inspection $c_1$, the cost of loss per unit time between failure and detection $c_2$, the cost of minimum repair of the detected breakdown of units $c_3$, and the overhaul cost $c_4$ of $R_s{\leq}R_g$. And in this paper, we will determine the optimal inspection policy to find the inspection period and number of tests that minimize the expected cost per unit time from the finite lifetime to the overhaul. Compare them through numerical examples.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.12
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• pp.1359-1364
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• 2012

The C-band semi-lumped lowpass filter with broad stopband and compact size characteristic using chip inductor is proposed. To provide an additional attenuation pole in stopband by SRF, a separable inductor is added to proposed structure, and it has broad stopband characteristic. The third order elliptic function lowpass filter with chip inductor(L: 9.1 nH, SRF: 5.5 GHz, Q: 25) has insertion loss of 0.38 dB, cutoff frequency of 920 MHz, broad stopband(below 20 dB) of 1.43~7.8 GHz and the size is reduced 37.4 % compared to distributed inductor.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.156-163
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• 2019

In this paper, we present the process of developing an automatic carrying and arming system for testing ammunition. When carrying out shooting tests at a domestic rifle range, most of the ammunition operations are carried out by human manpower The series of test processes, such as transporting, arming and firing of heavy munitions, is repeated by employing human. If the ammunition is loaded via manpower, then problems can occur such as loss of reliability of test results, musculoskeletal disorders of humans and also safety accidents can occur. To address these problems, an automated system was developed for the transport and operation of ammunition. This paper covers the design, manufacture and operation of the developed system. In addition, this study validated the effectiveness of the system as compared to the human operation. Our results show that the developed system can be easily adapted to testing ammunition at a domestic rifle range.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.4
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• pp.160-170
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• 2018

This paper is an exploratory study on the success factors of Defence Quality Management System (DQMS) which is the certification system granted by the military for improving the quality of munitions. DQMS is established by adding military requirements to the ISO standard, thus, we especially focus on the additional requirements to figure out success key factors of DQMS certification. The 51 additional requirements of Korean Defense Specification (KDS) are empirically investigated from 67 companies that acquired DQMS certification. Firstly, we conduct an independent t-tests on 51 additional requirements of KDS 0050-900-3 to determine if there is a difference between an easily certified company and a hard-to-certify company, and obtain 8 requirements such as 'Internal propagation of performance', 'Preparation of documented work instructions', 'Work instructions in the workplace', 'Documentation of equipment management', 'Inventory management', 'Packaging and identification', 'Guarantee of access to internal audit result for customers', 'Notification to the customer for improper product.' Secondly, we carry out an factor analysis to the 51 additional requirements for classification, and figure out that 4 requirements among the 8 requirements above mentioned are grouped together in the same factor. The 4 requirements are 'Preparation of documented work instructions', 'Work instructions in the workplace', 'Packaging and identification', and 'Guarantee of access to internal audit result for customers.' The result of this paper will provide useful information to the company preparing for DQMS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.751-758
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• 2021

Munitions must be analyzed to identify any risks for quality assurance in development and mass production. Risk identification for parts, compositions, and systems is carried out through failure mode effects analysis (FMEA) as one of the most reliable methods. FMEA is a design tool for the failure mode of risk identification and relies on the RPN (risk priority number). FMEA has disadvantages because its severity, occurrence, and detectability are rated at the same level. Fuzzy FMEA applies fuzzy logic to compensate for the shortcomings of FMEA. The fuzzy logic of Fuzzy FMEA is to express uncertainties about the phenomenon and provides quantitative values. In this paper, Fuzzy FMEA is applied to the failure mode of a rotorcraft landing system. The Fuzzy rule and membership functions were conducted in the Fuzzy model to study the RPN in the failure mode of a landing system. This method was selected to demonstrate crisp values of severity, occurrence, and detectability. In addition, the RPN was obtained. The results of Fuzzy FMEA for the landing system were analyzed for the RPN and ranking by fuzzy logic. Finally, Fuzzy FMEA confirmed that it could use the data in quality assurance activities for rotorcraft.

• The Journal of the Convergence on Culture Technology
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• v.8 no.4
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• pp.173-179
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• 2022

Through the 2014 Donbas conflict and the 2022 Ukraine-Russia war, we are experiencing that the command of the air is no longer only secured by the Air Force. Long-range surveillance reconnaissance and strikes carried out by the Air Force could be replaced by drones and missiles, and the enemy's aerial attacks could be controlled by air defense systems such as Panchir and portable anti-aircraft missiles, allowing ground forces to carry out maneuvers freely. In other words, it is much more advantageous for the air force and the navy to take control of the air through long-distance operations, and the ground forces should support them. Therefore, this study aims to consider the cost-effectiveness aspect of the delivery command of the air; it provides implications for quickly responding to enemy air attacks by developing the air defense weapon system, drones, missiles, precision-guided munitions, etc rather than focusing on expensive fighter jets.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.2
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• pp.119-143
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• 2021

Selecting liquid methane as fuel is a prevailing trend for recent rocket engine developments around the world, triggered by its affordability, reusability, storability for deep space exploration, and prospect for in-situ resource utilization. Given years of time required for acquiring a new rocket engine, a national-level R&D program to develop a methane engine is highly desirable at the earliest opportunity in order to catch up with this worldwide trend towards reusing launch vehicles for competitiveness and mission flexibility. In light of the monumental cost associated with development, fabrication, and testing of a booster stage engine, it is strategically a prudent choice to start with a low-thrust engine and build up space application cases.

• Journal of Aerospace System Engineering
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• v.17 no.4
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• pp.75-86
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• 2023

The guided missiles and decoy systems that have been developed have been likened to a spear and shield. When a new attack system appears, another defense system is developed, and the attack system is once again upgraded to neutralize it. Now, due to the limitations of the decoy system, guided weapons have become the main force of both the defense and attack systems. Also, these systems have been expanded to use Space systems as a means of defending against a guided weapon system that is too fast for terrestrial-based systems. Induced weapon systems started at the sub-sonic level, and have become so important that their speeds have become super-sonic and hyper-sonic. The concept of Space has been included in the range of guided missiles, and satellite systems have become essential elements of guided missiles. Focusing on the correlation between the guided missile system and the satellite system, we analyze the characteristics of modern guided munitions and the direction of development of the guided weapons system.