• Journal of the Korean Applied Science and Technology
• /
• v.36 no.4
• /
• pp.1060-1068
• /
• 2019

The physical fitness of the cadets of the Air Force Academy, which will protect the airspace of the Republic of Korea, is of paramount importance to fulfill the given mission. Therefore, the purpose of this study was to confirm the characteristics of body composition and physical fitness of female cadets of Air Force Academy and to verify their relationship with physical fitness according to body fat % level of total female cadets. To achieve the purpose of the study, 50 female cadets of the Korea Air Force Academy (1grade 13, 2grade 18, 3grade 9, 4grade 10) were measured in body composition (skeletal strength, body fat mass, body mass index, body fat %, abdominal obesity rate, basal metabolic rate) and physical fitness (muscle strength, muscular endurance, power, agility, flexibility and balance). One way ANOVA was performed for data processing to identify body composition and physical fitness characteristics by grade and to identify differences in physical fitness according to body fat rate levels. According to the study, the 1 grade was lower in body fat mass and body fat % among female cadets, the 2 grade was lower than the 3 and 4 grades, and the body mass index was lower than the third and fourth grades. Also, there was no difference in the physical fitness of the rest of the year. The intergroup physical fitness according to the body fat rate was higher than that of those with less than 20 percent of net worth and 25 percent to less than 25.1 percent to 30 percent, while those with less than 20 percent balance were higher than those with less than 25.1 to 30 percent. The results of this study showed differences in body composition by grade in female cadets, especially in power and balance according to body fat %. Therefore, female cadets of the Air Force Academy need to manage body fat to have the power and balance capability related to the airborne mission environment.

• Journal of the Korea Society of Computer and Information
• /
• v.25 no.3
• /
• pp.33-42
• /
• 2020

There has been difficulties in identifying objects by relying on the naked eye in various surveillance systems. There is a growing need for automated surveillance systems to replace soldiers in the field of military surveillance operations. Even though the object detection technology is developing rapidly in the civilian domain, but the research applied to the military is insufficient due to a lack of data and interest. Thus, in this paper, we applied one of deep learning algorithms, Convolutional Neural Network-based binary classification to develop an autonomous identification model of both friend and foe helicopters (AH-64, Mi-17) among the military weapon systems, and evaluated the model performance by considering accuracy, precision, recall and F-measure. As the result, the identification model demonstrates 97.8%, 97.3%, 98.5%, and 97.8 for accuracy, precision, recall and F-measure, respectively. In addition, we analyzed the feature map on convolution layers of the identification model in order to check which area of imagery is highly weighted. In general, rotary shaft of rotating wing, wheels, and air-intake on both of ally and foe helicopters played a major role in the performance of the identification model. This is the first study to attempt to classify images of helicopters among military weapons systems using CNN, and the model proposed in this study shows higher accuracy than the existing classification model for other weapons systems.

• Strategy21
• /
• s.43
• /
• pp.5-28
• /
• 2018

The tensions between the U.S and China, which form the two pillars of the G2 era, seem to have persisted even after the Trump administration inaugurated. The strong confrontation between the two in recent foreign security issues may drive to develop an inadvertent military conflict, and it is high likely to occur in the maritime are. The purpose of this study is not only to analyze the balance of modernized naval forces in the PLAN through naval strategy changes and weapons system modernization trend, but also to predict the impact of the geographical proximity difference on the balance of naval forces in the disputed areas. It examined the impact of distance and geography on naval power by assessing the modernization pattern of the PLAN and capabilities in the context of two scenarios at different distances from China by 2020: one centered on Taiwan and the other on the Spratly Islands. The PLAN's strategy had impact on operational concept and forces construction. First, from the viewpoint of operation operational concept, it can be seen that the passive defense is changing into active defense. Second, in terms of power construction, it can threaten the surface and submarines of U.S power from a distance. And they generated follow three features; The ocean is not the focus of Chinese submarines, Horizontal and vertical expansion of Chinese naval vessels, The improvement of the suppression ability as the Chinese naval modernization ratio increases. The strength of the PLAN is dominant over the U.S in terms of reserves, and it can complement the qualitative deterioration by utilizing nearby bases in the vicinity of the mainland, such as the Taiwan Strait. However, due to the shortage of aircraft carriers, there is a possibility that it will take some time to secure the advantage of air and ocean in the amphibious operation. Therefore, as the dispute is prolonged, China may fail to achieve its original goal. In addition, the lack of cutting edge Commanding Ships may bring to weaken the C2 capabilities. At results, it is expected that PLAN will not be able to have a superiority in the short term due to lagging behind U.S advanced technology. Nevertheless, PLAN has strengthened its naval power through modernization sufficiently and it is highly likely to use force. Especially, it is more likely in the region where the naval power operation like the Taiwan Strait is possible with the almost equality to that of the United States. China will continue to use its naval forces to achieve a rapid and decisive victory over U.S in the close area from the land.

• Composites Research
• /
• v.31 no.5
• /
• pp.260-266
• /
• 2018

This study investigates thermal and mechanical characterization of Hafnium carbide coating on the $C_f-C$ composites. The hafnium carbide coatings by vacuum plasma spray on the C/C-SiC composites are prepared to evaluate oxidation and wear resistance. We perform the thermal durability tests by thermal cycling at $1200^{\circ}C$ for 10cycles in air and investigates the weight change of each cycle. We also evaluate the wear and indentation behavior using tungsten carbide ball indenter as a mechanical evaluation. As a result, the HfC coating is beneficial to reduce of weight loss during thermal cycling test and improve the elastic property of C/C-SiC composite. Especially, the HfC coating improves the wear resistance of C/C-SiC composite.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.47 no.12
• /
• pp.874-880
• /
• 2019

This paper introduces a method which can be effectively used for the path planning of UAV in a realistic map which has mountainous terrains, air defense networks and radars based on the Visibility Graph. Existing studies of Visibility Graph have been studied mainly for simple shape obstacles in 2-dimensional environment such as self-driving cars which avoid buildings. However, for UAV, Visibility Graph must be used in 3-dimensional environment for the variance of altitude. This occurs significant elapsed time increase because of the increase of the amount of the visibility of node sets. To solve this problem, this paper decrease the number of nodes which consists the complex terrain environments using convex hull based on Layered Visibility Graph. With convex hull method, this paper confirmed that the elapsed time is decreased about 99.5% compared to the case which has no decrease of the number of nodes.

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

• Journal of International Area Studies (JIAS)
• /
• v.14 no.4
• /
• pp.27-52
• /
• 2011

The regions of Central Asia have each acquired an elevated strategic importance in the new security paradigm of post-September 1lth. Comprised of five states, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan, Central Asia's newly enhanced strategic importance stems from several other factors, ranging from trans-national threats posed by Islamic extremism, drug production and trafficking, to the geopolitical threats inherent in the region's location as a crossroads between Russia, Southwest Asia and China. Although the U.S. military presence in the region began before September 11th, the region became an important platform for the projection of U.S. military power against the Taliban in neighboring Afghanistan. The analysis goes on to warn that 'with US troops already in place to varying extents in Central Asian states, it becomes particularly important to understand the faultlines, geography, and other challenges this part of the world presents'. The Kyrgyz military remains an embryonic force with a weak chain of command, the ground force built to Cold War standards, and an almost total lack of air capabilities. Training, discipline and desertion - at over 10 per cent, the highest among the Central Asian republics - continue to present major problems for the creation of combat-effective armed forces. Kyrgyzstan has a declared policy of national defence and independence without the use of non-conventional weapons. Kyrgyzstan participates in the regional security structures, such as the Collective Security Treaty Organisation (CSTO) and the Shanghai Co-operation Organisation (SCO) but, in security matters at least, it is dependent upon Russian support. The armed forces are poorly trained and ill-equipped to fulfil an effective counter-insurgency or counter-terrorist role. The task of rebuilding is much bigger, and so are the stakes - the integrity and sovereignty of the Kyrgyz state. Only democratization, the fight against corruption, reforms in the military and educational sectors and strategic initiatives promoting internal economic integration and national cohesion hold the key to Kyrgyzstan's lasting future

• The Korean Journal of Air & Space Law and Policy
• /
• v.20 no.1
• /
• pp.211-253
• /
• 2005

Recently, the Korean Supreme Court released two important decisions concerning damages for the pain and suffering from Aircraft noise. The local people who are living near the Air Force practice site at Maehyang-ri and the Kimpo International Airport brought lawsuits against the Korean government requesting damages for their financial loss from the severe noise and the damages for their pain and suffering. Plaintiffs alleged that they suffered physical malfunctions, extreme disturbances and the reduction of property values from the extreme noises which were daily repeated. District Court of Seoul Province did not allow plaintiffs all but the damages for pain and suffering. Plaintiffs could not prove the causation between their financial loss and the noise. The Supreme Court confirmed the lower court's decision. Article V of the National Compensation Act (analogous to the Federal Tort Claims Act of the USA) reads, "the government shall be liable for any loss caused by the defect on establishment or maintenance of public facilities." In the two cases, the major issue was whether the government's establishment or maintenance of Air Force practice site and the airport was defective because they caused serious noise to surrounding neighbors. Previously, the Supreme Court interpreted the clause "defect on establishment or maintenance of public facilities" as failure of duty to provide safety measures to the degree generally required to ordinary manager. However the Court at this time interpreted differently that the defect could be found if the facility caused to any person loss to the degree intolerable. In the two cases the Court confirmed the lower court's finding that noise level at the site was severe enough to be intolerable. This standard is based on the severity of the loss rather than the failure of duty. It became easier for plaintiffs to prove the cause of action under this interpretation. The consequence of the ruling of these two cases is 'rush to the courtroom' by the local people at similar situations. The ruling of these two cases was not appropriate both in theory and in consequence. The Korean tort system is basically based on the theory of negligence. Strict liability is exceptional only when there is special legislation. The Court created strict liability rule by interpreting the Art. V of the National Compensation Act. This is against the proper role of the court. The result of the cases is also dismal. The government was already sued by a number of local people for damages. Especially the Department of Defense which is operating many airports nationwide has financial hardship, which will cause downsizing military practice by the Air Force in the long run, This is no good to anyone. Tens of millions of dollars which might be used for compensation might be better used to prevent further noise problem surrounding airports.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.47 no.4
• /
• pp.35-40
• /
• 2010

Skyline extraction in mountainous images which has been used for navigation of vehicles or micro unmanned air vehicles is very hard to implement because of the complexity of skyline shapes, occlusions by environments, dfficulties to detect precise edges and noises in an image. In spite of these difficulties, skyline extraction is avery important theme that can be applied to the various fields of unmanned vehicles applications. In this paper, we developed a robust skyline extraction algorithm using two-scale canny edge images, topological information and location of the skyline in an image. Two-scale canny edge images are composed of High Scale Canny edge image that satisfies good localization criterion and Low Scale Canny edge image that satisfies good detection criterion. By applying each image to the proper steps of the algorithm, we could obtain good performance to extract skyline in images under complex environments. The performance of the proposed algorithm is proved by experimental results using various images and compared with an existing method.

• Journal of Ocean Engineering and Technology
• /
• v.26 no.3
• /
• pp.13-19
• /
• 2012

Recently, as the importance of the interior noise in a ship cabin has risen, ship builders have becomeconcerned about the use of noise reduction panels to reduce cabin noise. The results of previous researches have been based on analytical and experimental methods using simple sandwich panels. However, panel structures are becoming more complex to improve the transmission loss. Thus, researches that analyze the transmission loss of a panel are reaching the limit of study. This paper reports on research that was performed to determine the sound transmission characteristics of multi-complex panels applicable to high value-added vessels. It presents comparisons between analytical methods and experimental results by using a mini-reverberant chamber with components of sound attenuation panels, including the core and surface materials. The sound transmission loss of multi-complex panels are also analyzed in terms of the influences of the inside perforate plates and air gap thickness on the attenuation. Finally, the multi-complex panel with the highest noise attenuation is proposed based on the analysis results and experimental results in mini-reverberant chamber, which wereverified using a real-size reverberant chamber.