• Journal of Navigation and Port Research
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• v.35 no.3
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• pp.197-204
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• 2011

The authors adopt the Unmanned Undersea Vehicle(UUV), the shape of which is like a manta. They call here it Manta UUV. Manta UUV has been designed from the similar concept of the UUV called Manta Test Vehicle(MTV), which was originally built by the Naval Undersea Warfare Center of USA(Lisiewicz and French, 2000; Simalis et al., 2001; U.S. Navy, 2004). The present study deals with the effect of Reynolds numbers on hydrodynamic forces acting on Manta UUV at large angles of attack. The large angles of attack cover the whole range of 0 to ${\pm}$ 180 degrees in horizontal plane and in vertical plane respectively. Static test at large attack angles has been carried out with two Manta UUV models in circulating water channel. The authors assume that the experimental results of hydrodynamic forces (lateral force, yaw moment, vertical force and pitch moment) are analyzed into two components, which are lift force component and cross-flow drag component. First of all, Based on two dimensional cross-flow drag coefficient at 90 degrees of attack angle, the cross-flow drag component at whole range of attack angles is calculated. Then the remainder is assumed to be the lift force component. The only cross-flow drag component is assumed to be subject to Reynolds number.entstly the authors suggest the methodology to predict hydrodynamic derivertives acting on the full-scale Manta UUV.

• Journal of Korea Technology Innovation Society
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• v.18 no.2
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• pp.292-317
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• 2015

As modern science and technology and warfare become to be advanced and precise, the weapon systems becomes more complex based on state-of-the-art technology. Therefore, firms in the defense industry continue to accelerate research and development for up-to-date weapon systems with high complexity which urge the firms to collaborate with the external organizations to obtain the knowledge required and eventually to reduce costs and risk. This study tries an empirical study about the effect of collaboration on the innovation performances from the network analysis perspective. By surveying collaboration relationships among 530 firms in the Korean defense industry, we analyzed the alliance network of the defense industry. Network centrality including degree, closeness, and betweenness centralities is investigated and then the relationship among the network centrality property, internal R&D capabilities and innovation is analysed. The results show that firms with high internal R&D capabilities place the firm at center of the network. On the other hand, except for the firms with highly connected centrality, no relationship was found between the internal R&D capabilities and its performance and in turn. these capabilities had both direct and indirect effects on innovation performances through mediated collaboration among firms. This study implied that Korean firms with a high internal R&D capabilities in the defense industry which utilize knowledge, information and resources within the network more frequently show more innovative performance. This result claims the policy makers to participate more firms in fostering open innovation for the defense industry.

• Journal of the Korea Society for Simulation
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• v.29 no.2
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• pp.105-117
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• 2020

Analysis of combat effectiveness is required to consider the concept of tactical cooperative engagement between manned-unmanned weapon systems, in order to predict the required operational capabilities of future weapon systems that meets the concept of 'effect-based synchronized operations.' However, analytical methods such as mathematical and statistical models make it difficult to analyze the effects of complex systems under nonlinear warfare. In this paper, we propose a combat simulation model that can simulate the concept of cooperative engagement between manned-unmanned combat entities based on wireless communications. First, we model unmanned combat entities, e.g., unmanned ground vehicles and drones, and manned combat entities, e.g., combatants and artillery, considering the capabilities required by the future ground system. We also simulate tactical behavior in which all entities perform their mission while sharing battlefield situation information through wireless communications. Finally we explore the feasibility of the proposed model by analyzing combat effectiveness such as target acquisition rate, remote control success rate, reconnaissance lead time, survival rate, and enemy's loss rate under a small-unit armor reconnaissance scenario. The proposed model is expected to be used in war-game combat experiments as well as analysis of the effects of manned-unmanned ground weapons.

• Journal of Convergence for Information Technology
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• v.11 no.4
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• pp.26-34
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• 2021

In the era of the Fourth Industrial Revolution, the future battlefield will carry out multi-area operations with hyper-connected, high-speed and mobile systems. In order to prepare for changes in the future, the Korean military intends to develop various weapons systems and form a multi-layer tactical network to support On The Move communication. However, current tactical networks are limited in support of On The Move communications. In other words, the operation of multi-beam antennas is necessary to efficiently construct a multi-layer tactical network in future warfare. Therefore, in this paper, we look at the need for multi-beam antennas through the operational scenario of a multi-layer tactical network. In addition, based on development consideration factors, features of rotary-wing and fixed-wing aircraft, we present the location and operation of airborne relay drone installations of multi-beam antennas.

• Journal of Internet Computing and Services
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• v.21 no.6
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• pp.1-12
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• 2020

Low-Orbit satellite mobile networks can provide services through miniaturized terminals with low transmission power, which can be used as reliable means of communication in the national public disaster network and defense sector. However, the high traffic environment in the emergency preparedness situation increases the new call blocking probability and the handover failure probability of the satellite network, and the increase of the handover failure probability affects the QoS because low orbit satellites move in orbit at a very high speed. Among the channel allocation methods of satellite communication, the FCA shows relatively better performance in a high traffic environment than DCA and is suitable for emergency preparedness situations, but in order to optimize QoS when traffic increases, the new call blocking and the handover failure must be minimized. In this paper, we propose LEO-DBC (LEO satellite dynamic beam width control) technique, which improves QoS by adaptive adjustment of beam width of low-orbit satellites and call time of terminals by improving FCA-QH method. Through the LEO-DBC technique, it is expected that the QoS of the mobile satellite communication network can be optimally maintained in high traffic environments in emergency preparedness situations.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.1
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• pp.9-16
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• 2023

Robots are expected to expand their scope of application to the military field and take on important missions such as surveillance and enemy detection in the coming future warfare. Swarm robots can perform tasks that are difficult or time-consuming for a single robot to be performed more efficiently due to the advantage of having multiple robots. Swarm robots require mutual recognition and collaboration. So they send and receive vast amounts of data, making it increasingly difficult to verify SW. Hardware-in-the-loop simulation used to increase the reliability of mission verification enables SW verification of complex swarm robots, but the amount of verification data exchanged between the HILS device and the simulator increases exponentially according to the number of systems to be verified. So communication overload may occur. In this paper, we propose a digital twin-based communication optimization technique to solve the communication overload problem that occurs in mission verification of swarm robots. Under the proposed Digital Twin based Multi HILS Framework, Network DT can efficiently allocate network resources to each robot according to the mission scenario through the Network Controller algorithm, and can satisfy all sensor generation rates required by individual robots participating in the group. In addition, as a result of an experiment on packet loss rate, it was possible to reduce the packet loss rate from 15.7% to 0.2%.

• Journal of Internet Computing and Services
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• v.22 no.6
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• pp.99-113
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• 2021

In these days, as cyberspace has been recognized as the fifth battlefield area following the land, sea, air, and space, attention has been focused on activities that view cyberspace as an operational and mission domain in earnest. Also, in the 21st century, cyber operations based on cyberspace are being developed as a 4th generation warfare method. In such an environment, the success of the operation is determined by the commander's decision. Therefore, in order to increase the rationality and objectivity of such decision-making, it is necessary to systematically establish and select a course of action (COA). In this study, COA is established by using the method of classifying operational elements necessary for cyber operation, and it is intended to suggest a direction for quantitative evaluation of COA. To this end, we propose a method of composing the COES (Cyber Operational Elements Set), which becomes the COA of operation, and classifying the cyber operational elements identified in the target development process based on the 5W1H Method. In addition, by applying the proposed classification method to the cyber operation elements used in the STUXNET attack case, the COES is formed to establish the attack COAs. Finally, after prioritizing the established COA, quantitative evaluation of the policy was performed to select the optimal COA.

• International Commerce and Information Review
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• v.15 no.3
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• pp.353-384
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• 2013

When it comes to the current inter-Korean relationship, the two Koreas are in the step of core practical negotiation on exchanges and cooperation away from deadlock so far. It is expected that they will have more and frequent meetings in the future. Therefore, now is the time the South Korea needed to come up with systematic countermeasures because there is nothing more important and giving more impact on our society than the matter of North Korea. As the purpose of social science lies with the explanation and prediction of the social phenomena in the society, it is considered to be meaningful to analyze the representative military negotiations such as the defense ministry-level talks, general-level talks, and working-level talks between the two Koreas where the participants from South Korea consisting of the military representatives discussed with their counterparts of North Korea since the signing of the armistice in Korea on July 27, 1953. This study analyzes and evaluates the behaviors of North Korea's military negotiations with the South Korea in the Kim Jong-il era on the overall basis. In particular, the research tries to prove that the behaviors of military negotiations under Kim Jeong-il regime were made in the frame of the negotiation model by analyzing many negotiations presented in 'With Century', Kim Il Sung's Memoirs under his anti-Japan-guerilla era and suggesting the analysis frame of anti-Japan-guerilla style negotiation model. Based on the results of this proof, the study looks at carefully the specific characteristics of anti-Japan guerrilla-type negotiation.