• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.4
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• pp.271-276
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• 2021

Arc fault detector based on multilevel DWT with analysis of high-frequency noise components over 100 kHz is proposed in this study to improve the performance in detecting serial arcs and distinguishing them from inverter noise in PV systems. PV inverters generally operate at a frequency range of 20-50 kHz for switching operation and maximum power tracking control, and the effect of these frequency components on the signal for arc detection leads to negative arc detection. High-speed ADC and multilevel DWT are used in this study to analyze frequency components above 100 kHz. Such high frequency components are less influenced by inverter noise and utilized to detect as well as separate DC series arc from inverter noise. Arc detectors identify the input current of PV inverters using a Rogowski coil. The sensed signal is filtered, amplified, and used in 800kSPS ADC and DWT analysis and arc occurrence determination in DSP. An arc detection simulation facility in UL1699B was constructed and AFD tests the proposed detector were conducted to verify the performance of arc detection and performance of distinction of the negative arc. The satisfactory performance of the arc detector meets the standard of arc detection and extinguishing time of UL1699B with an arc detection time of approximately 0.11 seconds.

• Journal of the military operations research society of Korea
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• v.26 no.2
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• pp.28-38
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• 2000

This research investigates a kill probability model for the performance evaluation of guided missile system, and also develops graphical user interface for the input and output of the model based on the visual object-oriented programming application. The major simulation events used in this research are missile guidance homing point, burst points, and kill mechanism(direct kill, blast kill and fragment kill). For the user interface, we also design and implement the visualization system that can show the graphic style of the kill probability attained by the model. The results of sample run are shown, but these could be improved to be better with visual simulation which can visulaize all the simulation process of the model.

• Convergence Security Journal
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• v.21 no.1
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• pp.177-189
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• 2021

Defense R&D is a key process for securing weapons systems determined by mid- and long-term needs to cope with changing future battlefield environments. In particular, the test and evaluation provides information necessary to determine whether or not to switch to mass production as the last gateway to research and development of weapons systems and plays an important role in ensuring performance linked to the life cycle of weapons systems. Meanwhile, if you look at the recent changes in the operational environment of the Korean Peninsula and the defense acquisition environment, you can see three main characteristics. First of all, continuous safety accidents occurred during the operation of the weapon system, which increased social interest in the safety of combatants, and the efficient execution of the limited defense budget is required as acquisition costs increase. In addition, strategic approaches are needed to respond to future battlefield environments such as robots, autonomous weapons systems (RAS), and cyber security test and evaluation. Therefore, in this study, we would like to present strategies for improving the testing and evaluation of weapons systems by considering the characteristics of the security environment that has changed recently. To this end, the improvement strategy was derived by analyzing the complementary elements of the current weapon system operational test and evaluation system in a multi-dimensional model and prioritized through the hierarchical analysis method (AHP).

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.515-520
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• 2001

Due to the high power to weight ratio and fast response under heavy load, the hydraulic systems are still applied to the development of many industrial facilities such as heavy duty construction vehicles, aerospace/military weapon actuating systems and motion simulators. Unlike the other actuators, single-rod hydraulic cylinder exhibits a lot different dynamic characteristics between the extending and retracting stroke because of the difference in pressure acting areas. In this research, in order to overcome this nonlinear feature, $H_{\infty}$ optimal controller was designed and implemented with DSP board that was specifically developed for the experiment. From the experimental result, we could confirm that the overall performance of single-rod hydraulic servo system is similar with the results as we expected in the design stage.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.5
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• pp.47-54
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• 2021

In this study, systems and procedures for improving the research and development and purchasing projects for defense specifications were investigated, and the current situation was analyzed in terms of the disclosure and establishment of defense specifications. I would like to discuss the measures that need to be taken to improve the specification affairs of our defense sector in order to improve the production quality of military supplies. It should be noted that it is necessary to establish specifications and procedures for improving the quality of domestically purchased military supplies. Therefore, it is highly imperative to systematically establish detailed performance, and miscellaneous specifications in order to actively respond to the rapid development of superior private technologies. In addition, the barriers in the entry of the defense industry should be removed through active disclosure of the specification data, and the opportunities for participation should be expanded to promote a smooth follow-up logistics support and to improve the quality of military supplies

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.9
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• pp.1412-1422
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• 2022

The importance of interoperability between weapon systems is continuously increasing. Usually it is implemented by data exchange. The existence of information heterogeneities between systems decreases the efficiency and quality of the implementations enterprise-widely. Many other developed countries increase the efficiency and quality of the implementations by using information exchange model commonly. However, Korean military is still not aware of the importance and necessity of the model. This study explains the necessity of development and adaptation of the Korea command and control information exchange model(KC2IEM), and presents the methodology for the development of the model, and verifies and improves it through a prototype model development. The completion of the information exchange model could not be possible by academic research, therefore this study contributes as a motivation and a stepping stone for the following developments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.647-654
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• 2016

In the defense industry, national security takes priority over economic sense and this has translated into high cost and long-term research and development. However, the exponential growth of technology and rapid changes in the security situation in recent years have resulted in a call for the development of systems at a low cost within a short period of time. In order to implement a modularization strategy in the field of defense, the introduction of line replaceable units in OO systems needs to be prioritized. This study selects six criteria following a literature review and prioritizes 11 modules for OO systems using the project evaluation method, Grey Relational Analysis (GRA). Based on the GRA results, the grey relational grades were derived as 0.83, 0.81 and 0.80 for the M11 (Main board), M8 (EMI module), M3 (Single board computer) modules, respectively. The cost and time of development is expected to be reduced in accordance with the grey relational grade. The results of this research could be utilized for decision making on adopting modularization in similar system development or product improvement programs (PIPs).

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.1
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• pp.185-194
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• 2023

The 4-axis strain-gauge, which is widely applied to military weapon systems, is operated in poor temperature and vibration conditions, tolerance may increase and malfunctions may occur. To improve this, this paper proposes a signal-processing software technique for the tolerance of the 4-axis strain gauge applied to a military weapon system. First, the tolerance of the strain-gauge and the signal processing circuit according to the ambient temperature were evaluated and analyzed. Second, a software technique for processing the dead zone and offset area that can improve the tolerance of the strain-gauge is proposed. The experimental results applying the software technique confirmed that it operated normally in the temperature test and operation test. Therefore, the proposed software technique is valid and can be used as useful information to improve tolerance due to ambient temperature and vibration when designing a system using a strain-gauge.

• Journal of the Korean Society of Systems Engineering
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• v.19 no.2
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• pp.135-144
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• 2023

Artificial Intelligence (AI) is a prominent topic in almost every field. In Korea, Systems Engineering (SE) procedures are applied in Defense Acquisition, and it is anticipated that SE procedures will also be applied to systems incorporating AI capabilities. This study explores the applicability of the concepts "AI4SE (AI for SE)" and "SE4AI (SE for AI)," which have been proposed in the United States, to the Korean context. The research examines the feasibility of applying these concepts, identifies necessary tasks, and proposes implementation strategies. For the AI4SE, many attempts and studies applying AI to SE Processes both Requirements & Architectures Define, System implementation & V&V, and Sustainment. It needs Explainability and Security. For the SE4AI, the Functional AI implementation level, Quality & Security of the Data-set, AI Ethics, and Review policies are needed. Furthermore, it provides perspectives on how these two concepts should ultimately converge and suggests future directions for development.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.6
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• pp.645-654
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• 2021

In this paper, we proposed a protocol to convert 2W telephone analog signals to Ethernet data in a private PSTN 2W tactical voice system. There are several kinds of operational problems in the tactical telephone network where 2W telephone copper lines are installed hundreds of meters away from the PBX in a headquarter site. The reason is that it is difficult to install and maintain the 2W telephone copper cable in severe operational fields and to meet safety and stability operational requirements of the telephone line under lighting and electromagnetic environments. In order to solve these challenging demands, we proposed an efficient method that the 2W analog interface signals between a private PBX system and a 2W telephone is converted to Ethernet messages using the optical Ethernet data communication network already deployed in the tactical weapon system. Thus, it is not necessary to install an additional optic cable for the ethernet telephone line and to maintain the private PSTN 2W telephone network. Also it provides safe and secure telecommunication operation under lightning and electromagnetic environments. This paper presents the conversion protocol from 2W telephone signals over Ethernet interface between PBX systems and 2W telephones, the mutual exchange protocol of ethernet messages between two converters, and the rule to process analog signal interface. Finally, we demonstrate that the proposed technique can provide a feasible solution in the tactical weapon system by analyzing its performance and experimental results such as the bandwidth of 2W telephone ethernet network and the transmission latency of voice signal, and the stability of optic ethernet voice network along with the ethernet data network.