In this study, lead-free (LiNaK)(NbTaSb)O 3 piezoelectric ceramics were fabricated on the basis of the amount of K 2 CO 3 addition, and their piezoelectric and dielectric properties were investigated by varying the amount of K 2 CO 3 addition and poling temperature. First, to achieve optimum poling conditions for manufactured specimens, the poling temperature was varied to be 0, 20, 50, 80, and 110 C. The optimum poling temperature was 20 C. It was found that 0.1 wt % K 2 CO 3 -added (Li 0:04 Na 0:44 K 0:52 ) (Nb 0:86 Ta 0:1 Sb 0:04 )O 3 ceramics exhibit excellent piezoelectric properties in an experiment performed on the basis of the amount of K 2 CO 3 addition. That is, a 0.1 wt % K 2 CO 3 -added specimen showed a large electromechanical coupling factor k p ¼ 0:494, a large piezoelectric constant d 33 ¼ 274 pC/N, and a high density of 4.65 g/cm 3 at the poling temperature of 20 C.

No abstract

North Korean cyber-attack groups such as Kimsuky, Lazarus, Andariel, and Venus 121 continue to attempt spear-phishing APT attacks that exploit social issues, including COVID-19. Thus, along with the worldwide pandemic of COVID-19, related threats also persist in cyberspace. In January 2022, a hacking attack, presumed to be Kimsuky, a North Korean cyber-attack group, intending to steal research data related to COVID-19. The problem is that the activities of cyber-attack groups are continuously increasing, and it is difficult to accurately identify cyber-attack groups and attack origins only with limited analysis information. To solve this problem, it is necessary to expand the scope of data analysis by using BGP archive data. It is necessary to combine infrastructure and network information to draw correlations and to be able to classify infrastructure by attack group very accurately. Network-based infrastructure analysis is required in the fragmentary host area, such as malware or system logs. This paper studied cyber ISR and BGP and a case study of cyber ISR visualization for situational awareness, hacking trends of North Korean cyber-attack groups, and cyber-attack tracking. Through related research, we estimated the origin of the attack by analyzing hacking cases through cyber intelligence-based profiling techniques and correlation analysis using BGP archive data. Based on the analysis results, we propose an implementation of the cyber ISR visualization method based on BGP archive data. Future research will include a connection with research on a cyber command-and-control system, a study on the cyber battlefield area, cyber ISR, and a traceback visualization model for the origin of the attack. The final R&D goal is to develop an AI-based cyber-attack group automatic identification and attack-origin tracking platform by analyzing cyber-attack behavior and infrastructure lifecycle.

It is essential to build a practical environment of the training/test site for cyber training and weapon system test evaluation. In a military environment, cyber training sites should be continuously developed according to the characteristics of the military. Weapons with cyber security capabilities should be deployed through cyber security certification. Recently, each military has been building its own cyber range that simulates its battlefield environment. However, since the actual battlefield is an integrated operation environment, the cyber range built does not reflect the integrated battlefield environment that is interconnected. This paper proposes a configuration plan and operation function to construct a multi-cyber range reflecting the characteristics of each military to overcome this situation. In order to test the multi-cyber range, which has scenario authoring and operation functions, and can faithfully reflect reality, the impact of DDoS attacks is tested. It is a key to real-world mission-based test evaluation to ensure interoperability between military systems. As a result of the experiment, it was concluded that if a DDoS attack occurs due to the infiltration of malicious code into the military network, it may have a serious impact on securing message interoperability between systems in the military network. Cyber range construction technology is being developed not only in the military, but also in school education and businesses. The proposed technology can also be applied to the construction of cyber ranges in industries where cyber-physical systems are emphasized. In addition, it is a field that is continuously developing with the development of technology, such as being applied as an experimental site for learning machine learning systems.

Most of the challenges and conflicts facing countries and groups today involve cyberspace. Therefore, military forces around the world are developing methods (doctrines) and weapon systems to conduct cyberspace operations in order to dominate cyberspace. To conduct cyberspace operations, cyber target information must be collected in cyberspace, and cyber targets must be selected to achieve effective operational objectives. In this study, we develop a target importance rank (TIR) algorithm based on the PageRank algorithm that quantitatively calculates the importance of each target in cyberspace for cyber target selection. The proposed algorithm was developed to quantify the degree of connectivity, criticality, and exposure of computer network hosts, and to create a list of target importance priorities based on the quantified values.