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Unknown Attack Detection:Combining Relabeling and Hybrid Intrusion Detection

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Computers, Materials & Continua 2021年第9期68卷 3289-3303页

作者： Gun-Yoon Shin Dong-Wook Kim Sang-Soo Kim Myung-Mook Han Department of Computer Engineering Gachon UniversitySungnam-si13120Korea agency for defense development songpa Seoul05661Korea Department of Software Gachon UniversitySungnam-si13120Korea

Detection of unknown attacks like a zero-day attack is a research field that has long been ***,advances in Machine Learning(ML)and Artificial Intelligence(AI)have led to the emergence of many kinds of attack-generation tools developed using these technologies to evade detection *** detection and misuse detection are the most commonly used techniques for detecting intrusion by unknown *** anomaly detection is adequate for detecting unknown attacks,its disadvantage is the possibility of high false *** detection has low false alarms;its limitation is that it can detect only known *** overcome such limitations,many researchers have proposed a hybrid intrusion detection that integrates these two detection *** method can overcome the limitations of conventional methods and works better in detecting unknown ***,this method does not accurately classify attacks like similar to normal or known ***,we proposed a hybrid intrusion detection to detect unknown attacks similar to normal and known *** anomaly detection,the model was designed to perform normal detection using Fuzzy c-means(FCM)and identify attacks hidden in normal predicted data using *** misuse detection,the model was designed to detect previously known attacks using Classification and Regression Trees(CART)and apply Isolation Forest(iForest)to classify unknown attacks hidden in known *** an experiment result,the application of relabeling improved attack detection accuracy in anomaly detection by approximately 11%and enhanced the performance of unknown attack detection in misuse detection by approximately 10%.

关键词： Unknown attack hybrid intrusion detection fuzzy c-means relabeling CART iForest

Measurement of alumina film induced ablation of internal insulator in solid rocket environment

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Defence Technology（防务技术） 2023年第11期29卷 181-192页

作者： Ji-Yeul Bae In Sik Hwang Yoongoo Kang agency for defense development 160488th Bukyuseong-streetDaejeonSouth Korea

This study investigates the ablation of internal insulation induced by the deposition of an alumina film with different lateral film speeds.A sub-scale test solid rocket motor(SRM)was designed in an impinging jet configuration to form an alumina film on the sample and to encourage the lateral movement of the film by a high-speed wall *** static fire tests of the test SRM were conducted with six different jet velocities(V_(jet)=100 m/s,150 m/s,200 m/s,268 m/s,330 m/s,and 450 m/s)that indirectly affected the velocity of the wall jet and the deposition rate of alumina *** ablation velocity was deduced from the difference in the sample thickness after a test using a coordinate measuring *** droplet deposition mass flux and wall jet velocity were obtained via two-phase flow simulation with the same jet velocity and effective *** a result,the characteristics of alumina-induced ablation and the changes in ablation with jet velocities were *** area within0.8×jet diameter was focused upon,where the ratio of ablation velocity to incoming alumina mass was constant for each jet velocity,and showed a similarity in jet *** the ablation velocity was increased from 2.05 to 9.98 mm/s with increasing jet velocity,the ratio of the ablation velocity and alumina mass flux decreased from 1.07×10^(-4)to 0.49×10^(-4)m^(3)/kg as Al_(2)O_(3)-C reactions became less efficient with a reduced residence time of the *** the decrease in residence time by the wall jet is more pronounced for slow reactions involved in Al_(2)O_(3)-C reactions,fast reactions in Al_(2)O_(3)-C reactions are less affected and result in a convergence of the volumetric rate of ablation per unit mass of alumina.

关键词： Internal insulation Solid rocket motor Ablation Alumina

Integrated guidance and control for damping augmented system via convex optimization

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Chinese Journal of Aeronautics 2022年第7期35卷 30-39页

作者： Bong-Gyun PARK Tae-Hun KIM The 1^(st)R&D Institute-4 Agency for Defense DevelopmentDaejeon 34186Republic of Korea

In this paper,an integrated guidance and control approach is presented to improve the performance of the missile *** approach includes damping augmented system with attitude rate feedback to decrease the oscillation during the homing phase for missiles with low *** addition,physical constraints,which can affect the performance of the missile interception,such as acceleration limit,seeker’s look angle,and look angle rate constraints are *** integrated guidance and control problem is formulated as a convex quadratic optimization problem with equality and inequality constraints,and the solution is obtained by a primal–dual interior point *** performance of the proposed method is verified through several numerical examples.

关键词： Convex optimization Damping augmented system Integrated guidance and control Physical constraint Primal-dual interior point method

A fast-running method for blast load prediction shielding by a protective barrier

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Defence Technology（防务技术） 2020年第2期16卷 308-315页

作者： S.-H.Sung J.-W.Chong agency for defense development Yuseong P.O.Box 35DaeJeon395-600South Korea

This study presents a simplified blast load prediction method on structures behind a protective *** proposed method is basically an empirical approach based on Kingery-Bulamsh(K-B)chart and finite element(FE)analysis *** this end,this study divides the structure into three regions by three critical *** loads at each critical point can be calculated based on K-B chart and an approximation according to FE analysis ***,peak reflected overpressure and impulse distributed on the structure can be approximately estimated by linearly connecting blast loads at each critical *** order to confirm a feasibility of the proposed method,a series of numerical simulations were carried *** simulation results were compared with FE analysis results which are presented in the open *** such comparisons,it was found that the proposed method is applicable to predict blast loads on structures behind a protective barrier.

关键词： Blast loads Protective barrier Shock wave Fast running model Kingery-Bulmash

Simulation of wind-induced near-inertial oscillations in a mixed layer near the east coast of Korea in the East/Japan Sea

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Acta Oceanologica Sinica 2013年第9期32卷 11-20页

作者： NAM SungHyun PARK Young-Gyu Naval Systems development Center Agency for Defense Development Ocean Circulation and Climate Research Division Korea Institute of Ocean Science and Technology

Using a simple damped slab model, it was possible to show that a local wind induced 88% （15 of 17） of the near-inertial oscillations （NIO） observed in the mixed layer near the east coast of Korea from 1999 to 2004. The model, however, overestimated the energy level in about two-thirds of the simulated cases, because the slab model was forced with winds whose characteristic period was shorter than the damping time scale of the model at 1.5 d. At the observation site, due to typhoons and orographic effects, high-frequency wind forcing is quite common, as is the overestimation of the energy level in the slab model results. In short, a simple slab model with a damping time-scale of about 1.5 d would be enough to show that the local wind was the main energy source of the near-inertial energy in this area, but the model could not be used to accurately estimate the amount of the work done by the wind to the mixed layer.

关键词： near-inertial oscillations near-inertial waves slab model high-frequency wind forcing eastcoast of Korea

Coupled CUBIC Congestion Control for MPTCP in Broadband Networks

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Computer Systems Science & Engineering 2023年第4期45卷 99-115页

作者： Jae Yong Lee Byung Chul Kim Youngmi Kwon Kimoon Han Department of Information and Communications Engineering Chungnam National UniversityDaejeon34134Korea agency for defense development Daejeon34186Korea

Recently,multipath transmission control protocol(MPTCP)was standardized so that data can be transmitted through multiple paths to utilize all available path ***,when high-speed long-distance networks are included in MPTCP paths,the traffic transmission performance of MPTCP is severely deteriorated,especially in case the multiple paths’characteristics are heavily *** order to alleviate this problem,we propose a“Coupled CUBIC congestion control”that adopts TCP CUBIC on a large bandwidth-delay product(BDP)path in a linked increase manner for maintaining fairness with an ordinary TCP traversing the same bottleneck *** verify the performance excellence of the proposed algorithm,we implemented the Coupled CUBIC Congestion Control into Linux kernels by modifying the legacy MPTCP linked-increases algorithm(LIA)congestion control source *** constructed asymmetric heterogeneous network testbeds mixed with large and small BDP paths and compared the performances of LIA and Coupled CUBIC by *** results show that the proposed Coupled CUBIC utilizes almost over 80%of the bandwidth resource in the high BDP path,while the LIA utilizes only less than 20%of the bandwidth for the same *** was confirmed that the resource utilization and traffic transmission performance have been greatly improved by using the proposed Coupled CUBIC in high-speed multipath networks,as well as maintaining MPTCP fairness with competing single-path CUBIC or Reno TCP flows.

关键词： MPTCP congestion control Coupled CUBIC high BDP network

2.47 GPa grade ultra-strong 15Co-12Ni secondary hardening steel with superior ductility and fracture toughness

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Journal of Materials Science & Technology 2021年第7期66卷 36-45页

作者： Young-Kyun Kim Kyu-Sik Kim Young-Beum Song Jung Hyo Park Kee-Ahn Lee Department of Materials Science and Engineering Inha UniversityIncheon22212Republic of Korea agency for defense development(ADD) Yuseong-guDaegeon34186Republic of Korea

This study investigated the effect of multi-step heat treatment on the microstructure, mechanical properties and fracture behavior of thick 15 Co-12 Ni secondary hardening steel. As-quenched sample was found to have elongated prior austenite grain(PAG) and coarse lenticular martensitic structure. On the other hand, heat-treated sample was observed to have fine lenticular martensitic structure due to fine PAG size and a lot of nano-sized carbides. Also, after heat treatment, nano-scale reverted austenite film was formed at the martensite interfaces. The heat-treated sample showed 2.47 GPa superior tensile strength and superior elongation of about 12 %. The high strength was mainly due to fine block size and high number density of nano-sized carbides. The average value of plane strain fracture toughness(KIC) was 29.3 MPa m1/2, which indicated a good fracture toughness even with the high tensile strength. The tensile fracture surface was observed to have ductile fracture mode(cup-and-cone) and the formation of about ~1 μm ultra-fine dimples. In addition to this, nano-sized carbides were observed within the *** findings suggested that the nano-sized carbide had a positive effect not only on the strength but also on the ductility of the alloy. The fractured surface after toughness test, also showed ductile fracture mode with a lot of dimples. Based on the above results, correlation among microstructural evolution,deformation and fracture mechanisms along the heat-treatment was also discussed.

关键词： Ultra-high strength High Co-Ni secondary hardening steel Microstructure Tensile properties Fracture toughness Reverted austenite

Generation and measurement of arbitrary four-dimensional spatial entanglement between photons in multicore fibers

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Photonics Research 2019年第1期7卷 19-27页

作者： HEE JUNG LEE HEE SU PARK Korea Research Institute of Standards and Science(KRISS) agency for defense development

High-dimensional entanglement is a valuable resource for secure and efficient quantum information processing.A major challenge for practical use of multidimensional quantum systems is the establishment of controls over arbitrary superposition states in realistic conditions. This work demonstrates spatially entangled photon pairs propagating through two separate four-core optical fibers with the amplitudes and phases of the superposition being independently controllable. Using quantum state analyzers that can detect arbitrary multicore superposition states, Bell-type CGLMP inequalities in two, three, and four dimensions are directly tested. Enhanced violation of the inequality by slight nonmaximality of entanglement is also demonstrated.

关键词： High-dimensional entanglement efficient quantum demonstrates spatially

Weapon effectiveness and the shapes of damage functions

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Defence Technology（防务技术） 2021年第2期17卷 617-632页

作者： Sei-Hoon Moon th R&D Institute Agency for Defense DevelopmentYusungDaejeon305-152Republic of Korea Department of Mechanical and Aerospace Engineering Naval Postgraduate School MontereyCA93940USA

This paper provides a review of methods of assessing a fragmentation weapon’s effectiveness against a point target or an area target with keeping the focus on the necessity of using the Carleton damage function with the correct shape ***,cookie-cutter damage functions are redefined to preserve the shape factor of and to have the same lethal area as the corresponding Carleton damage ***,closed-form solutions of the effectiveness methods are obtained by using those cookie-cutter damage functions and the Carleton damage ***,the closed-form solutions are applied to calculate the probability of damaging a point target and the expected fractional damage to an area target for several attack scenarios by using cookie-cutter damage functions and the Carleton damage functions with different shape *** comparison of the calculation results shows that using cookie-cutter damage functions or the Carleton damage function with a wrong shape factor results in quite significant differences from using the original Carleton damage function with a correct shape factor when weapon’s delivery error deviations are less than or comparable to the lengths of the lethal area and the aim point is far from a *** effectiveness methods improved in this paper will be useful for mission planning utilizing the precision-guided munitions in circumstances where the collateral damage should be reduced.

关键词： Weapon effectiveness Point target Area target Cookie-cutter damage function Carleton damage function