• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.139-142
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• 2012

The deign and development status of a combustion chamber test facility(CTF), a turbopump real propellant test facility(TPTF), a rocket engine test facility for 3rd stage engine(SReTF), a rocket engine ground/high altitude test facility(ReTF, HAReTF) and a propulsion system test complex(PSTC) for KSLV-II is briefly described. The development/qualification tests of engine component, 3rd stage engine system and 75ton-class liquid rocket engine system will be performed in CTF, TPTF, SReTF, ReTF and HAReTF and the development test of $1^{st}/2^{nd}/3^{rd}$ propulsion systems for KSLV-II will be performed in PSTC. The CTF/TPTF are under construction such as ordering the long delivery items and the detailed design of ReTF/PSTC is being prepared.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.241-244
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• 2011

Recently, Due to development of Internet techniques, user suddenly increased that Used of Web services and with out constraints of place and time has been provided. typically, Web services used ID/Password authentication. User confirmed personal data Stored on Web servers after user authorized. web service provider is to provide variety security techniques for the protection personal information. However, recently accident has happened is the malicious attackers may capture user information such as users entered personal information through new keyboard hooking. In this paper, we propose a keyboard hooking protected password input method using CAPTCHA. The proposed password input method is based on entering the password using mouse click or touch pad on the CAPTCHA image. The mapping of CAPTCHA image pixels is random.

• Journal of the Korea Society for Simulation
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• v.18 no.3
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• pp.133-138
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• 2009

When sensor networks are deployed in open environments, an adversary may compromise some sensor nodes and use them to inject false sensing reports. False report attack can lead to not only false alarms but also the depletion of limited energy resources in battery powered networks. The Interleaved hop-by-hop authentication (IHA) scheme detects such false reports through interleaved authentication. In IHA, when a report is forwarded to the base station, all nodes on the path must spend energies on receiving, authenticating, and transmitting it. An dversary can spend energies in nodes by using the methods as a relaying attack which uses macro. The Adversary aim to drain the finite amount of energies in sensor nodes without sending false reports to BS, the result paralyzing sensor network. In this paper, we propose a countermeasure using fuzzy logic from the Denial of Service(DoS) attack and show an efficiency of energy through the simulataion result.

• Journal of Industrial Convergence
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• v.22 no.2
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• pp.63-71
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• 2024

Conventional methods like PIN used in conventional smartphone form factor have not considered the variation in display structure or screen size. As a result, when applied to recent variable display-based smartphones, the secret information input unit may get reduced or enlarged, leading to vulnerabilities for social engineering attacks due to deformation of the display area. This study proposes a secure keypad that responds to changes in display size in rollable and bendable smart phones. Firstly, the security problems that may arise when applying classical authentication methods to new form factors were analyzed, and corresponding security requirements were derived. The proposed security keypad addresses the key input error problem that can occur when the screen size is small. The arrangement and size of keys can be deformed with the spacing suitable for input depending on the display size of rollable and bendable smartphones. The study also considered the problem of leaking input information for social engineering attacks by irregularly distributing key input coordinates. The proposed method provides better user experience and security than existing methods and can be used in smartphones of various sizes and shapes.

• Korean Journal of Environmental Biology
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• v.37 no.3
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• pp.309-316
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• 2019

Cropland is a major source of atmospheric nitrous oxide (N₂O) and we need technologies in the field of agriculture that can reduce the presence of N₂O. In this study, a field experiment encompassing six treatments was conducted to determine the efflux of N₂O in cropland during the growing season. An experimental plot was composed of two main sectors, no-tillage (NT) and conventional tillage (CT), which were subdivided into three plots according to types of nitrogen (N) sources: CF, chemical fertilizer; HV, hairy vetch+chemical fertilizer; and RY, rye+chemical fertilizer. The cumulative N₂O emissions were 179.8 mg N₂O m^-2 for CF-CT, 108.1 mg N₂O m^-2 for HV-CT, 303.5 mg N₂O m^-2 for RY-CT, 86.7 mg N₂O m^-2 for CF-NT, 73.8 mg N₂O m^-2 for HV-NT, and 122.7 mg N₂O m^-2 for RY-NT during the fallow season. The CT, HV, and RY of no-tilled soils were reduced by 51.8, 31.7 and 59.6%, respectively (p<0.001). Our results indicate that the use of no-tillage and hairy vetch practice rather than conventional tillage and chemical fertilizer practice can decrease N₂O emission.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.9
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• pp.39-45
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• 2009

When Mobile IPv6 is deployed in commercial network, a mobile node needs AAA services for an authentication, authorization and accounting. AAA and Mobile IPv6 are protocols which are operated independently. Then schemes which merge these protocols have been emerged. These schemes can enable a mobile node to establish a security association between the mobile node and a home agent and to perform a binding update for the home agent using AAA authentication request. But these schemes introduce many signal messages and long handover latency during the handover, since Route Optimization mode for Mobile Ipv6 is performed using Return Routability procedure. To solve this problem, we propose a scheme for Route Optimization mode that the home agent performs the binding update for a correspondent node via the AAA infrastructure between the home agent and the correspondent node instead of Return Routability procedure. For performance evaluation, we analyze signal message transmission costs and handover latencies during handover. We show performance improvement of the proposed scheme which reduces handover latency as 61% compared with the existing scheme.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06d
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• pp.248-251
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• 2011

무선 센서 네트워크는 다양한 응용 분야와 환경에 배치되기 때문에, 악의적인 목적을 가진 사용자의 공격에 손쉽게 노출되어 있다. 선택적 전달 공격은 센서 네트워크에서 발생 할 수 있는 가장 대표적인 라우팅 공격 중의 하나로, 데이터 패킷의 정상적인 전달을 차단하여 상황 인지 및 이에 대한 대응을 지연시킨다. 기존에 제안된 탐지 기법은 패킷 전달 경로 상에 감시 노드를 선정하고, 패킷이 전송 될 때마다 인증메시지를 소스 노드에게 전송하여 공격 발생 여부를 탐지한다. 하지만, 패킷을 전송할 때 마다 공격 탐지를 수행하기 때문에 한정된 에너지를 바탕으로 동작하는 센서 네트워크에 적합하지 못하다. 본 논문에서는 탐지율을 충분히 유지하면서도 높은 에너지 효율성 위해 센서 네트워크의 특성을 고려한 선택적 전달 공격 탐지 기법을 제안한다. 제안하는 기법에서는 기존 기법에서와 같이 즉시 탐지를 수행하는 대신에 패킷 전송 시간을 고려한 네트워크 모니터링을 수행하고, 공격 받았을 가능성이 있는 경로에 대해서만 지연탐지를 수행한다. 본 논문의 우수성을 보이기 위해서 시뮬레이션을 통해 성능 평가를 수행하였으며, 그 결과 기존 기법에 비해 탐지율이 평균 약 15% 향상되었고, 네트워크의 에너지 소모량이 평균 약 54% 감소하였다.

• Convergence Security Journal
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• v.18 no.1
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• pp.157-166
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• 2018

This study conducted a perfect detection of explosives by placing various devices and personnel in place of terrorist bomb detection in a situation that is difficult to detect and protect against the use of explosives not only in countries but also in civilians. The result is that the legal system applies, first, the obligation to introduce bomb-sniffing dogs for national critical and large civil facilities. Secondly, it introduces a certification system for bomb-sniffing dogs to verify their detection capabilities. Third, it is to introduce a system for fostering expert manpower to activate expert water supply companies that operate bomb-sniffing dogs.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.1
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• pp.43-56
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• 2012

Wireless sensor networks consist of numerous small-sized nodes equipped with limited computing power and storage as well as energy-limited disposable batteries. In this networks, nodes are deployed in a large given area and communicate with each other in short distances via wireless links. For energy efficient networks, dynamic clustering protocol is an effective technique to achieve prolonged network lifetime, scalability, and load balancing which are known as important requirements. this technique has a characteristic that sensing data which gathered by many nodes are aggregated by cluster head node. In the case of cluster head node is exposed by attacker, there is no guarantee of safe and stable network. Therefore, for secure communications in such a sensor network, it is important to be able to encrypt the messages transmitted by sensor nodes. Especially, cluster based sensor networks that are designed for energy efficient, strongly recommended suitable key management and authentication methods to guarantee optimal stability. To achieve secured network, we propose a key management scheme which is appropriate for hierarchical sensor networks. Proposed scheme is based on polynomial key pool pre-distribution scheme, and sustain a stable network through key authentication process.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.3
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• pp.39-47
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• 2022

In this paper, we proposed a thickness measurement method of concrete slab using GPR, and the verification of the suggested algorithm was carried out through real-scale experiment. The thickness measurement algorithm developed in this study is to set the relative dielectric constant based on the unique shape of parabola, and time series data can be converted to thickness information. GPR scanning were conducted in four types of slab structure for noise reduction, including finishing mortar, autoclaved lightweight concrete, and noise damping layer. The thickness obtained by GPR was compared with Boring data, and the average error was 1.95 mm. In order to investigate the effect of finishing materials on the slab, additional three types of finishing materials were placed, and the following average error was 1.70 mm. In addition, sampling interval from device, the effect of radius on the shape of parabola, and Boring error were comprehensively discussed. Based on the experimental verification, GPR scanning and the suggested algorithm have a great potential that they can be applied to the thickness measurement of finishing mortar from concrete slab with high accuracy.