• Bulletin of the Society of Naval Architects of Korea
• /
• v.56 no.3
• /
• pp.20-28
• /
• 2019

• Journal of Advanced Navigation Technology
• /
• v.22 no.2
• /
• pp.123-132
• /
• 2018

In this paper, we design and fabricate a dual liner polarization sinuous antenna with improved cross polarization isolation (XPI). The proposed antenna is composed of four arm radiators for generating dual linear polarization and excited by wideband microstrip balun with Klopfenstein taper structure. Also, two-step cylindrical cavity structure is applied to reduce back radiation. Honeycomb-typed absorbing material is inserted into the cavity to reduce performance degradation by reflected wave. To enhance cross polarization isolation in low frequency band, resistors are adapted between outer arm and the rim of cavity. We confirmed that the fabricated antenna can be applied for polarization measurement due to improved XPI in the low band.

• KIPS Transactions on Software and Data Engineering
• /
• v.10 no.6
• /
• pp.201-210
• /
• 2021

Navigation Software for the various weapon systems has common functionalities which give the possibility of common use among them. SPL(Software Product Line) framework of the navigation software for weapon system refers to developing a standardized navigation software platform from common functionalities of navigation software, managing the standardized navigation software platform, and developing weapon system navigation software such as navigation software for missile, UAV(Unmanned Air Vehicle), submarine, and etc. from the standardized navigation software platform. In this paper, we propose SPL based navigation software development process, Integrated Development Environment and operational concept of SPL framework. The operational concept will be defined by specifying the role of every stake holders and their activity scenario. The Operational concept would be referenced to implement SPL for other domain through using with detail implementation guide.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.32 no.4
• /
• pp.673-689
• /
• 2022

We propose an APT attack scoring method as a part of the process for detecting and responding to APT attacks. First, unlike previous work that considered inconsistent and subjective factors determined by cyber security experts in the process of scoring cyber attacks, we identify quantifiable factors from components of MITRE ATT&CK^Ⓡ techniques and propose a method of quantifying each identified factor. Then, we propose a method of calculating the score of the unit attack technique from the quantified factors, and the score of the entire APT attack composed of one or more multiple attack techniques. We present the possibility of quantification to determine the threat level and urgency of cyber attacks by applying the proposed scoring method to the APT attack reports, which contains the hundreds of APT attack cases occurred worldwide. Using our work, it will be possible to determine whether actual cyber attacks have occurred in the process of detecting APT attacks, and respond to more urgent and important cyber attacks by estimating the priority of APT attacks.

• Applied Chemistry for Engineering
• /
• v.29 no.6
• /
• pp.696-702
• /
• 2018

Recently, the current thermal battery technology needs new materials for electrodes in the power and energy density to meet various space and defense requirements. In this paper, to replace the pellet type Li(Si) anode having limitations of the formability and capacity, electrochemical properties of the lithium anode with high density for thermal batteries were investigated. The lithium anode (Li 17, 15, 13 wt%) was fabricated by mixing the molten lithium and iron powder used as a binder to hold the molten lithium at $500^{\circ}C$. The single cell with 13 wt% lithium showed a stable performance. The 2.06 V (OCV) of the lithium anode was significantly improved compared to 1.93 V (OCV) of the Li(Si) anode. Specific capacities during the first phase of the lithium anode and Li(Si) were 1,632 and $1,181As{\cdot}g^{-1}$, respectively. As a result of the thermal battery performance test at both room and high temperatures, the voltage and operating time of lithium anode thermal batteries were superior to those of using Li(Si) anode thermal batteries. The power and energy densities of Li anode thermal batteries were also remarkably improved.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.27 no.2
• /
• pp.277-284
• /
• 2024

For the high reliability of guidance weapon, it is important to maintain the stable supply voltage for guidance system while the bomb is gliding. However, the DC motor drive for guidance control in the low temperature can lead to the critical voltage drop due to a large inrush current. In this paper, we propose the wing deployment logic design to enhance the guidance system stability. To derive the stable drive logic based on PWM, we controlled the duty cycles for input voltage of DC motor in low temperature. The initial duty cycle was set to 40 % to relieve the inrush current. Moreover, the proper time, which is less than 1 second for controlling duty cycles, was determined by the iterative wing deployments of guidance kit. Finally, the validity of proposed logic was confirmed from the result the maximum voltage drop for the wing deployment was decreased by 23 %.

• The Journal of the Acoustical Society of Korea
• /
• v.38 no.2
• /
• pp.193-199
• /
• 2019

In this paper, the results of underwater vibration experiment are analyzed to verify platform vibration-induced noise isolation characteristics of a hull-mounted acoustic sensor. The experimental condition causing platform vibration-induced noise is generated using the mock-up hull, where the acoustic sensor is installed, with shaker in an acoustic water tank. The performance indices of ATF (Acceleration Transfer Function), AVS (Acceleration Voltage Sensitivity), and IL (Insertion Loss) for the acoustic sensor are calculated from the output of the standard accelerometers, which are installed on the mock-up hull and the acoustic sensor, and the output signal of the acoustic sensor. The frequency-dependent noise isolation characteristics of the acoustic sensor are analyzed based on the calculated performance indices and an effectiveness of the experiment is examined.

• Defense and Technology
• /
• no.1 s.131
• /
• pp.66-75
• /
• 1990

필자가 현재 몸담고 있는 국방과학연구소는 지금부터 20년전인 1970년 8월에 창설되었으며, 그동안 국방과학기술 연구와 무기체계 개발을 통해 군의 전력강화와 방위산업 육성에 기여하여 왔다. 이러한 연구소의 업적을 기록으로 남기기 위한 소사편찬사업이 1987년부터 시작되었으며, 필자가 그 일을 맡게 되었다. 이러한 일에 경험이 없던 필자로서는 이 분야의 전문가와 연구소 창설요원들 그리고 연구소가 창설되기전 국방부나 각군에서 조병 및 연구개발에 관여했던 선배들로부터 많은 조언과 자료를 받았다. 그때 수집된 자료중에는 지나치게 세부적이거나 야사적인 성격의 내용 때문에 아깝긴 하지만 국방과학 연구소사에 포함시킬수 없는 것이 많았다. 또한 우리 연구소의 특수성 때문에 연구소사가 군사비밀로 발간되었으므로 비밀에 속하지 않는 내용까지도 일반에 대한 공개가 어렵게 되었다. 이러한 아쉬움을 조금이나마 덜수 없을까 하는 생각과 우리나라에서는 아직 이분야의 활동을 소개한 글이 없었기 때문에 관심있는 분들이 가벼운 마음으로 읽어보며, 조금이라도 궁금증을 덜수 있다면 다행이라는 생각으로 이 글을 쓰게 되었다.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.24 no.5
• /
• pp.527-536
• /
• 2021

In wireless environments, wideband receivers are used in a communication intelligent system to detect unknown signals and obtain azimuth information. To design a wideband receiver that performs multiple signal detection and direction finding simultaneously, it is necessary to consider a reception structure composed of multiple channels. In this paper, we propose a wideband multi-channel receiver for direction finding of unknown wideband communication signals including frequency hopping signals. A signal processing method for detecting received signals and estimating azimuth information is presented, and components of the manufactured wideband receiver are described. In addition, test results of the signal detection performance by mounting the proposed wideband multi-channel receiver on the flight system are included.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.21 no.6
• /
• pp.731-743
• /
• 2018

In this paper, a study result to decide the accuracy specifications of inertial sensors satisfying the performance requirements of SINS(ship's inertial navigation system) is proposed. To do this, the performance specifications of overseas SINS is surveyed and the detailed error analysis of SINS at stationary condition is performed. Also, a new performance index to indicate the performance of SINS is derived. Modelling and simulation results show that the accuracy specifications of inertial sensors to meet the performance requirements of SIGMA40XP, a typical overseas SINS, can be determined through the newly derived performance index in this paper.