• Current Optics and Photonics
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• v.5 no.4
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• pp.466-476
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• 2021

Frequency-multiplication technology based on microwave photonic principles can be used to generate microwave and millimeter wave signals with a wide frequency tuning range. However, the existing cascaded external modulation frequency-tupling scheme needs to ensure the phase coherence of the modulated Radio Frequency (RF) signal, while the phase modulation directly limits the frequency tuning range of the external modulation frequency multiplication. In this paper, a novel approach for generating an incoherent frequency 12-tupling signal with cascade modulation is proposed. The structure of cascaded dual-parallel Mach-Zehnder modulators can generate a frequency 12-tupling signal. The proposed structure uses no filter or phase control of the RF driving signal. Microwave photonic frequency-tupling was realized under incoherent conditions. Software simulations and experiments validated the proposed structure and proved that it can generate frequency 12-tupling microwave signals under incoherent conditions. Both the frequency range and reliability of the frequency-tupling system has been improved by the proposed structure.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.3
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• pp.346-354
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• 2024

Deep learning models require high computing power due to a substantial amount of computation. It is difficult to use them in devices with limited computing environments, such as coastal surveillance equipments. In this study, a lightweight model is constructed by analyzing the weight changes of the convolutional layers during the training process based on MobileNet and then pruning the layers that affects the model less. The performance comparison results show that the lightweight model maintains performance while reducing computational load, parameters, model size, and data processing speed. As a result of this study, an effective pruning method for constructing lightweight deep learning models and the possibility of using equipment resources efficiently through lightweight models in limited computing environments such as coastal surveillance equipments are presented.

• Journal of Digital Convergence
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• v.10 no.9
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• pp.1-13
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• 2012

This study aims to analyze actual conditions of the present national defense information network operation, the structure and management of the system, communication lines, security equipments for the lines, the management of network and software, stored data and transferred data and even general vulnerable factors of our army tactical C4I system. Out of them, by carrying out an extensive analysis of the army tactical C4I system, likely to be the core of future information warfare, this study suggested plans adaptive to better information security, based on the vulnerable factors provided. Firstly, by suggesting various information security factor technologies, such as VPN (virtual private network), IPDS (intrusion prevention & detection system) and firewall system against virus and malicious software as well as security operation systems and validation programs, this study provided plans to improve the network, hardware (computer security), communication lines (communication security). Secondly, to prepare against hacking warfare which has been a social issue recently, this study suggested plans to establish countermeasures to increase the efficiency of the army tactical C4I system by investigating possible threats through an analysis of hacking techniques. Thirdly, to establish a more rational and efficient national defense information security system, this study provided a foundation by suggesting several priority factors, such as information security-related institutions and regulations and organization alignment and supplementation. On the basis of the results above, this study came to the following conclusion. To establish a successful information security system, it is essential to compose and operate an efficient 'Integrated Security System' that can detect and promptly cope with intrusion behaviors in real time through various different-type security systems and sustain the component information properly by analyzing intrusion-related information.

• Convergence Security Journal
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• v.15 no.4
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• pp.127-139
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• 2015

The purpose of this research is to reevaluate the success factors and significance of the battle through the analysis of the only successful Chuncheon district battle during the defense combat in the early part of the Korean War on June 25, 1950. The research results are the matters that are analyzed from the viewpoint of the armed forces of the Republic of Korea, focusing intensively on the successful aspect of the early defense combat against North Korean army's surprise invasion of the South and on the battle that thwarted the North Korean army's intensive surprise attack intention. This research attempts to reanalyze the Chuncheon District Battle in connection with the Kim Il-sung's strategic course of action in consideration of the operation plan of North Korean invasion of the South. In other words, it is to reanalyze the enemy tactics in connection with North Korean army's plan of invasion of the South. The fact that the 6th Division of the armed forces of the Republic of Korea destroyed the North Korean army's operations plans that were in accordance with Kim Il-sung's strategic plans has more significance than a simple tactical success. The Chuncheon District Battle should be reevaluated as the "decisive battle" which went beyond a successful early defense combat in a Chuncheon region, and which fundamentally defeated North Korean army's war plan itself by thwarting the Kim Il-sung's strategic plan.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.399-406
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• 2020

The R.O.K Army has developed and operated TM to maintain the operation of weapons systems since its establishment. As more modern weapons systems were developed, the more efficient operation was limited by a large quantity. As a countermeasure, the DAPA has operated the IETM using the KAIS TOOL since 2003. However, 16 years later, they were shunned by operators for software instability and other reasons. Based on the results of an operational test and evaluation team of the Army headquarters, the analysis results of software instability, limited compatibility and integration, limited real-time updates, etc. were analyzed. It was confirmed that KAIS development tools were urgently needed. Therefore, in order to solve this current problem for the Army IETM, the first phase of this paper focused on improving the IETM by maintaining the application present, the second of the Army Electronic Technology manual, phase going to propose improvement plans for operational test and evaluation by lining 11 elements of comprehensive logistics support with an electronic technology code.

• Korean Security Journal
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• no.15
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• pp.107-128
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• 2008

It was started that Shiwe-goon was organized from Shilla-end to Goryeo foundation a country in powerful families existence merely royal household by stably plan means in the reign of Taejo. Generally Shiwe-goon was dutie king' personal danger of protection. Shiwe-goon was organized castle of guarding, stand by king and royal household side armed strength to going on a trip and general armed-organization was collapsed for Goryeo-end continued existence. Goryeo era of Shiwe-organization was divided central army and region army. Two-goon(Eungyang-goon, Yongho-goon) was undertaken king of Shiwe army and six-we(Chunwoo-we, Geumoh-we, Gammoon-we, Jeoawoo-we, Shinoh-we, Hongwe-we) was undertaked capital of guard and the border of defense duty. Central army of commanders was called Sangjanggoon, Daejanggoon. Sangjanggoon and Daejanggoon was discussed military officer of conference apparatus in Jungbang. Jungbang was got afterward Mooshinjungbeon happened military of statesman grasping political power with authority a main stay. Mooshinjungkwen era was appeared modernistic mean of privately guarding organization in Dobang and Naedobang. According as Shiwe-organization was charged military organization as a part of sovereign power and grasping strength of authority- maintenance for security and guarding duty. As a conclusion, national sovereign of guard was achieved not only personal life and body guard protection but also country of welfare protection in country-welfare dimension an inch of non-error. Also national sovereign of guard was considered guarding apparatus of allowance the largest duty and country-welfare direct connection with actual fact recognition in constancy effort.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.4
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• pp.493-500
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• 2013

In this study, it was evaluated the protective performance of the protection material for filed of the army by impact of fragment from the explosion of 155mm artillery shell to propose the improvement items. And it was evaluated the protection materials for structural boby such as corrugated steel plate, concrete block, prevention paint of explosion, aluminum foam and concrete T-wall by impact of fragment of 155mm artillery shells and explosion-induced pressure of C-4 explosive. As a result, protective performance of the existing protective material was superior but reinforcement is necessary for secondary damage because sand is leaking. The protective performance of new protective materials was greater than existing protective materials. And it can be used for protective materials.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.10
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• pp.1-8
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• 2021

Cylinder liners used in diesel engines of combat equipment are prone to cavitation due to wet cooling. The damage caused by erosion and corrosion due to cavitation has a fatal effect on the performance and lifespan of a diesel engine. Therefore, a study was conducted to improve the durability of cylinder liners. Two surface treatment techniques were proposed: nitriding and chrome plating. It was observed that the amount of erosion on the surface of nitride-treated cylinder liners was high because the surface-treated part eroded due to its weak impact resistance against the bubble explosion generated by cavitation. In contrast, the chrome-plated cylinder liner had a lower amount of erosion among the specimens subjected to the accelerated test. These results verified that the resistance of chrome-plated liners against cavitation is high. Therefore, it can withstand the impact of bubble explosion. If the chrome plating thickness is set with reference to the KS standard, an exceptional durability of abrasion, wear resistance, and corrosion resistance can be obtained. If the thickness is set between 120~250㎛, it is expected that the durability of the cylinder liner can be improved. Although a recovery method for corroded cylinder liners is suggested, the proposed method has an inherent risk of crack generation. Therefore, further research is required to solve this problem.

• Journal of National Security and Military Science
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• s.15
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• pp.31-55
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• 2018

It has been fifteen years since military science was introduced into private and public universities since 2004. The department focuses on the improvements of the South Korean Army quality based on the Korean Army's traits including: an increase of power in the armed force and operations through research, development, and the expansion of a cooperation between the public (civilians) and military. Approximately, four hundred students from various universities in the military science department graduate in order to become an officer. The fourth industrial revolution causes structural transformation to our lives. Through the use of Artificial Intelligence (AI,) war and the military as a whole will be altered significantly particularly with regard to efficiency. Nevertheless, it is important for us to train officers in creative ways so that they can deal with situations where machines will be unable to handle situations. Considering this change in our lives, it is necessary for the military science departments to change the way to teach and train their students. In order to accomplish this goal, we need to introduce a method called "Flipped Learning" and during the process all the members need to participate and communicate in an interactive way. By doing this, the military science departments will play an important role by improving human resource in terms of military and national security.

• Geomechanics and Engineering
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• v.30 no.6
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• pp.579-586
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• 2022

Pile-supported structures are installed on saturated sloping grounds, where the ground stiffness may decrease due to liquefaction during earthquakes. Thus, it is important to consider saturated sloping ground and pile interactions. In this study, we conduct a centrifuge test of a pile-supported structure, and analyze the p-y_p loops, p-y_p loops provide the correlation between the lateral pile deflection (y_p) and lateral soil resistance (p). In the dry sand model (UV67), the p-y_p loops stiffness increased as ground depth increased, and the p-y_p loops stiffness was larger by approximately three times when the pile moved to the upslope direction, compared with when it moved to the downslope direction. In contrast, no significant difference was observed in the stiffness with the ground depth and pile moving direction in the saturated sand model (SV69). Furthermore, we identify the unstable zone based on the result of the lateral soil resistance (p). In the case of the SV69 model, the maximum depth of the unstable zone is five times larger than that of the dry sand model, and it was found that the saturated sand model was affected significantly by kinematic forces due to slope failure.