• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.230-233
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• 2014

Latest Inforamtion security threats and risks change very rapidly, and there to strengthen the security level of the major companies and organizations are diversified attack to respond to a penetration test conducted. Penetration test(PenTest) is safer for the purpose of looking for vulnerabilities in computer systems by taking advantage of vulnerabilities discovered in the same way as a hacker attack. How to make a security vulnerability could be exploited by attempting to attack show. On the other hand, many security companies are testing in a variety of ways to be penetrated. However, penetration testing to evaluate the strength and reliability has not performed yet. Therefore, in this study, Penetration testing to validate and present a reliable method of evaluation. In this study, penetration testing, assessment information to provide the evaluation results are more reliable. And, as a result, efficient penetration test is expected to be possible.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.12
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• pp.1670-1675
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• 2020

In this study, to provide the basis for establishing effective network based countermeasures against DRDoS(Distributed Reflection Denial of Service) attacks, we propose a new 'DRDoS attack multi-level detection method' that identifies the network based characteristics of DRDoS and applies probability and statistical techniques. The proposed method removes the limit to which normal traffic can be indiscriminately blocked by unlimited competition in network bandwidth by amplification of reflectors, which is characteristic of DRDoS. This means that by comparing 'Server to Server' and 'Outbound Session Incremental' for it, accurate DRDoS identification and detection is possible and only statistical and probabilistic thresholds are applied to traffic. Thus, network-based information security systems can take advantage of this to completely eliminate DRDoS attack frames. Therefore, it is expected that this study will contribute greatly to identifying and responding to DRDoS attacks.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.147-153
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• 2020

Developments in aircraft require safety verification through flight testing for many hours with prototype design and production. The test evaluation step of performing flight tests was an important process that determines the success in the development of the system. In particular, safety development through flight tests in the armed flight test is important for the development of attack helicopters. In the development of attack helicopters, the evaluation period and cost related to the armed flight test are closely related to the required ammunition requirement. Therefore, this paper presents the amount of ammunition required for the military flight test between attack helicopter developments through an analysis of the AH-1 helicopter in a similar case and ADS-44-HDBK of military specification. The AH-1 can be used to calculate the ammunition demand by considering the exclusion of redundant firing tests and configuration differences. In the case of the machine gun-equipped configuration, approximately 10,500R was required, and approximately 324R was required in the case of a rocket-mounted configuration. In addition, if the armed integrated bench is used properly, it is expected to promote efficiently the flight test in the armed flight by identifying the possible risk factors with armed flight tests and excluding them.

• Journal of information and communication convergence engineering
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• v.12 no.1
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• pp.33-38
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• 2014

This paper investigates the shaping operation problem introduced by Callahan et al., namely the k-fragility maximization problem (k-FMP), whose goal is to find a subset of personals within a terrorist group such that the regeneration capability of the residual group without the personals is minimized. To improve the impact of the shaping operation, the degree centrality of the residual graph needs to be maximized. In this paper, we propose a new greedy algorithm for k-FMP. We discover some interesting discrete properties and use this to design a more thorough greedy algorithm for k-FMP. Our simulation result shows that the proposed algorithm outperforms Callahan et al.'s algorithm in terms of maximizing degree centrality. While our algorithm incurs higher running time (factor of k), given that the applications of the problem is expected to allow sufficient amount of time for thorough computation and k is expected to be much smaller than the size of input graph in reality, our algorithm has a better merit in practice.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.1
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• pp.39-49
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• 2021

The behaviors of various desorption agents were investigated during the desorption of cesium (Cs) from samples of clay minerals and actual soil. Results showed that polymeric cation exchange agents (polyethyleneimine (PEI)) efficiently desorbed Cs from expandable montmorillonite, whereas acidic desorption solutions containing HCl or PEI removed considerable Cs from hydrobiotite. However, most desorption agents could desorb only 54% of Cs from illite because of Cs's specific adsorption to selective adsorption sites. Cs desorption from an actual soil sample containing Cs-selective clay mineral illite (< 200 ㎛) and extracted from near South Korea's Kori Nuclear Power Plant was also investigated. Considerable adsorbed 137Cs was expected to be located at Cs-selective sites when the 137Cs loading was much lower than the sample's cation exchange capacity. At this low 137Cs loading, the total Cs amount desorbed by repeated washing varied by desorption agent in the order HCl > PEI > NH4+, and the highest Cs desorption amount achieved using HCl was 83%. Unlike other desorption agents with only cation exchange capabilities, HCl can attack minerals and induce dissolution of metallic elements. HCl's ability to both alter minerals and induce H+/Cs+ ion exchange is expected to promote Cs desorption from actual soil samples.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.287-296
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• 2011

Turnout is a mechanical installation enabling railway trains to be guided from one track to another at a railway junction. A movable nose crossing frog is a device used at a railway turnout to eliminate the gap at the common crossing (High manganese, block, assembly crossing)which can cause impact damage, noise and vibration. Our government has a plan speed up of conventional line to 250km/h semi-high speed. We had already developed flexible turnout with fixed crossing(High manganese) and SFC fastening system can cover in the semi-high speed line In this study is about development of the movable nose crossing turnout available Semi-high speed line on concrete track. This paper describes about geometry, attack angle, bending stress at the nose, switching force, safety of continuous welded long rails. This movable nose crossing turnout is expected greatly increases passing speed of turnout in national railway.

• International Journal of Aeronautical and Space Sciences
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• v.14 no.1
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• pp.1-10
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• 2013

This is a written version of the keynote speech delivered at the International Symposium on Hypersonic Aerothermodynamics - Recent Advances held in Bangalore, India, from December $6^{th}$ to $10^{th}$, 2012. In this document, what was accomplished in the past, the present status, and what is expected in the future in the field of hypersonic aerothermodynamics are reviewed. Solved problems are categorized into four items; unsolved problems into twelve items, and emerging problems into four items. Removing one degree uncertainty in trim angle of attack, studying the thermochemical phenomena in a hydrogen-helium-methane mixture, and entry flights of meteoroids are cited as the tasks for the future.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.1
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• pp.150-156
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• 2006

A Flapping foil Produces an effective angle of attack, resulting in a normal force vector with thrust and lift components, and it can be expected to be a new highly effective propulsion system. A heaving foil model was made and it was operated within a circulating water channel at low Reynolds numbers. The unsteady thrust and lift acting on the heaving foil were measured simultaneously using a 6-axis force sensor based on force and moment detectors. We have been examined various conditions such as heaving frequency and amplitude in NACA 0010 Profile. The results showed that thrust coefficient and efficiency increased with reduced frequency and amplitude. We also Presented the experimental results on the unsteady fluid forces of a heaving foil at various Parameters.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.5 s.236
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• pp.639-646
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• 2005

As the internet communication is prevalent in recent years, it becomes quite possible to monitor and control some mechanical plants from the remote place through the TCP/IP communication. Such a concept is expected to be applied to many industrial systems fur easy maintenance and trouble shooting as well as various kinds of expensive test equipments fo. sharing. Synthetic jet actuate.(SJA) is a kind of high-lifting device to prevent flow separation at high angle of attack and its use for flow control has received a great amount of attention. In this research, remote control and data monitoring system for SJA wind tunnel test is implemented by TCP/IP communication with DSP as a embedded web server. From the tests performed with embedded server, it showed the possibility of reliable remote control system design utilizing the internet communication.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.6
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• pp.5-13
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• 2008

A smart submunition drops through the expected trajectory to have a appropriate target searching footprint for the armored ground vehicles. Parachutes can be used as a tool to decelerate and spin the submunition. Usually submunition's descent velocity, spin rate, submunition inclination angle against vertical and dynamic stability affect to its target searching footprint. Therefore it is important to design optimal parachute and load configuration for the overall system performance. In this paper we described the dynamic motion of submunition by the mathematical model of parachute and load. Through the computer simulation we can analyze the submunition footprint affected by parachute and load design.