• The Journal of Society for e-Business Studies
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• v.20 no.4
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• pp.127-150
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• 2015

Since 9/11 attack, internet has become a major space for terrorist activities and also emerged as the most important spot of lone wolf terrorists for acquiring tools and radicalization. The accident of student Kim's defection to IS (Islamic state) in January 2015 told us that Korea is not any more "terrorism clearance area" and leaded us to look closely into the possibility of lone wolf terrorist. In this paper, I developed a "lone wolf cyber evolution model" using various materials collected by preceding papers and interviewing investigators and terrorism experts in Korea. I analyze Kim's radicalization process using this model. And I picked and closely looked over some facilitating factors of lone wolf such as multi-cultural socialization, increase of international migrants, expansion alienation hierarchy and ideological conflicts deepening and predicted the possibility of lone wolf. Finally, this paper presents some effective policy measurements against lone wolf terrorism in Korea.

• Journal of the Society of Naval Architects of Korea
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• v.37 no.3
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• pp.57-68
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• 2000

The Power Augmented Ram(PAR) effect, which blows the down stream of the propellers into the underside of the wings and hence increases the pressure between the lower surface of the wings and the sea surface, is known significantly to enhance the performance of the WIG concept by reducing the take-off and landing speeds. The aerodynamic characteristics of a 20 passenger PARWIG are investigated by wind tunnel tests with the 1/20 scale model. The efflux of the forward mounted propellers are simulated by jet flows with a blower and duct system. The lift, drag, and pitch moment of the model with various ground clearances, angles of attack and flap angles are measured for the various jet velocities, jet nozzle angles, horizontal and vertical positions of the nozzle, and the nozzle diameters. The aerodynamic characteristics of the PARWIG due to these parametric changes are compared and pertinent discussions are included. It is shown that the proper use of the PAR can increase the lift coefficient of as much as up to 4.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1350-1355
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• 2011

It is very important issues to protect many system resources using authorized client authentication in distributed client server systems. So it is not enough to prevent unauthorized opponents from attacking our systems that client authentication is performed using only the client's identifier and password. In this paper, we propose a secure authentication database modeling with two authentication keys such as a client authentication key and a server authentication key. The proposed authentication model can be used making high quality of computer security using two authentication keys during transaction processing. The two authentication keys are created by client and server, and are used in every request transaction without user's extra input. Using the proposed authentication keys, we can detect intrusion during authorized client's transaction processing because we can know intrusion immediately through comparing stored authentication keys in client server systems when hackers attack our network or computer systems.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.4
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• pp.667-677
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• 2013

As the firewall is a typical network security equipment, it is usually installed at most of internal/external networks and makes many packet data in/out. So analyzing the its logs stored in it can provide important and fundamental data on the network security research. However, along with development of communications technology, the speed of internet network is improved and then the amount of log data is becoming 'Massive Data' or 'BigData'. In this trend, there are limits to analyze log data using the traditional database model RDBMS. In this paper, through our Method of Analyzing Firewall log data using MapReduce based on NoSQL, we have discovered that the introducing NoSQL data base model can more effectively analyze the massive log data than the traditional one. We have demonstrated execellent performance of the NoSQL by comparing the performance of data processing with existing RDBMS. Also the proposed method is evaluated by experiments that detect the three attack patterns and shown that it is highly effective.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.10
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• pp.798-805
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• 2018

This study introduces an adaptive design of experiment (DoE) approach for the hypersonic shock-tunnel testing. A series of experiments are conducted to model the pitch moment coefficient of a cone as the function of the angle of attack and the pitch rate. An algorithm to construct the trajectory of the test model from the images obtained by the high-speed camera is developed to effectively analyze multiple time series experimental data. An adaptive DoE procedure to determine the experimental point based on the analysis results of the past experiments using the algorithm is proposed.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.42 no.4
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• pp.217-227
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• 2006

This research aims at establishing the application of canvas kite to the fishing gear through the analysis of the lift/drag tests of the kites have been performed in our previous finding. Now that several methodologies were designed to find the most effective triangular model as a buoyancy device applied to the fishing gear. Comparisons of drag/lift were made by installing the model in an installation frame instead of the prototype. Also, we have considered the application of canvas kite to the prototypic fishing gear by calculation using the result of this test. The results obtained from the above approaches are summarized as follows, where attack angle, lift coefficient, maximum lift coefficient and drag coefficient are denoted as $B,\;C_L,\;C_Lmax\;and\;C_D$ respectively. The camber showed a gradual increase with an increase of fluid velocity. There was a big discrepancy in B=20 unlike B=30. Even if the kite retreats along the fluid flow, there is little relationship with the velocity variation. Lifts calculated with the kites were bigger and drags were smaller than those of the calculations with the float only. The kite as the buoyancy device will be very useful when the appropriate applications and the stability are met.

• Journal of Navigation and Port Research
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• v.29 no.6 s.102
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• pp.509-513
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• 2005

Ship maneuverability is mainly determined according to hull-propeller-rudder system of a ship and directly related to the ship safety during the operation in the ocean. Among hull-propeller-rudder system the rudder system had direct concern with the ship maneuverability and a special rudder has been recommended to improve the ship maneuverability. In this paper the study of flapped rudder's 2-dimensional section was accomplished Model tests had been carried out with different angles of attack of a main foil and flap's deflection angles to predict the performance of the flapped rudder and the 2 frame particle tracking method had been used to obtain the velocity distribution in the flow field during model tests. $Re=1.027{\times}10^4$ had been used during the whole experiments and measured results had been compared with each other.

• Convergence Security Journal
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• v.19 no.4
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• pp.97-105
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• 2019

With the possibility of wireless control of the aircraft by Nicola Tesla, Unmanned Aerial Vehicle(UAV) was mainly used for military and defense purposes with the rapid development through World War I and II. As civilian applications of unmanned aerial vehicles have expanded, they have been used with various services, and attempts have been made to control various environmental changes and risk factors of unmanned aerial vehicles. However, GPS spoofing, Jamming attack and security accidents are occurring due to the communication in the unmaned aerial vehicle system or the security vulnerability of the unmanned aerial vehicle itself. In order to secure introduction of Unmanned aerial vehicle, South Korea has established Unmanned Aerial Vehicle verification system called Airworthiness Certification. However, the existing cerfication system is more focused on test flight, design and structure's safety and reliability. In this paper, we propose a unmanned aerial vehicle system model and propose security functional requirements on unmanned aerial vehicle system in the corresponding system model for secure-introduction of Unmanned Aerial Vehicle. We suggest the development direction of verification technology. From this proposal, future development directions of evaluation and verification technology of Unmanned Aerial Vehicle will be presented.

• Convergence Security Journal
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• v.11 no.6
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• pp.67-72
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• 2011

A system that provides a ubiquitous service is a networked system that has to overcome their circumstances that the service survivability is weak. the survivability of a networked system is defined as an ability of the system that can offer their services without interruption, regardless of whether components comprising the system are under failures, crashes, or physical attacks. This paper presents an approach that end users can obtain a quantitative evaluation of U-service survivability to reflect intended cyber attacks causing the networked system to fall into byzantine failures in addition to the definition of the survivability. In this paper, a Jini system based on wireless local area networks is used as an example for quantitative evaluation of U-service survivability. This paper also presents an continuous time markov chain (CTMC) Model for evaluation of survivability of U-service that a Jini system provides, and an approach to evaluate the survivability of the U-service as a blocking probability that end users can not access U-services.

• Convergence Security Journal
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• v.16 no.7
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• pp.21-29
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• 2016

Our society is currently exposed to environment of various information that is exchanged real time through networks. Especially regarding medical policy, the government rushes to practice remote medical treatment to improve the quality of medical services for citizens. The remote medical practice requires establishment of medical information based on big data for customized treatment regardless of where patients are. This study suggests establishment of regional medical cluster along with defense and protection cooperation models that in case service availability is harmed, and attacks occur, the attacks can be detected, and proper measures can be taken. For this, the study suggested forming networks with nationwide local government hospitals as regional virtual medical cluster bases by the same medical information system. The study also designed a mutual cooperation security model that can real time cope with IP Spoofing attack that can occur in the medical cluster and DDoS attacks accordingly, so that the limit that sole system and sole security policy have can be overcome.