• Journal of the Korea Institute of Military Science and Technology
• /
• v.19 no.4
• /
• pp.551-558
• /
• 2016

We analyzed wind speed over South Korea for HALE UAV(High Altitude Long Endurance Unmaned Aerial Vehicle) flight safety. Annual variation of wind speed at 200 hPa showed that winter season was stronger than summer. According to latitude, wind speeds in January and August were found to be $52{\sim}74m\;s^{-1}$ and $15{\sim}26m\;s^{-1}$, respectively. Wind speed was stronger(weaker) at lower latitudes than higher latitudes in winter(summer). Frequency(%) of wind speed less than threshold value($18m\;s^{-1}$) for the operation date was investigated. The days showing the frequency greater than 60 % in all altitudes of surface ~ 50 hPa showed the range of 1 ~ 33 days at 7 stations. Operation date was the longest period at Gosan. The appropriate date of HALE UAV operation at Gosan and Osan is considered as the middle of July ~ middle of August and end of July ~ early August, respectively. These results can be used to determine the operation date of HALE UAV.

• Journal of the Korea Institute of Building Construction
• /
• v.20 no.4
• /
• pp.375-382
• /
• 2020

Rock drop obstacles on major roads in the border area in South Korea has been installed and operated to prevent and block the movement of enemy units. However, the increase in traffic volume due to the development of the border region causes many problems such as road traffic congestion due to rock drop, traffic safety, and impaired urban aesthetics. Therefore, this study aimed to provide guidelines for demolition and replacement facility installation for rock drop obstacles, which are differently applied to each unit, and to suggest the direction of the Ministry of National Defense's policy regarding maintenance cost for necessary rock drop obstacles required for operation. In this study, as part of a guideline study on the removal of rock drop obstacles and the installation of alternative facilities, a standard unit price was suggested for essential rock drop obstacles, so as to be used as judgment data when deciding whether to remove rock drop obstacles.

• Korean Journal of Construction Engineering and Management
• /
• v.17 no.4
• /
• pp.87-94
• /
• 2016

The necessity to consider stability of underground structures constructed below or adjacent ammunition depots has been increased since the expansion of urban area and construction of infrastructure. However, there are a few studies on influence of accidental explosion on underground structures. In this study, the process of assessing the stability of underground structures is suggested and its applicability is verified through the case study. AUTODYN and SPACECLAIM are used to execute the structure and geotechnical modelling, and explosion effect is simulated and vibration velocities are calculated. According to the result of this case study, it is concluded that underground structure constructed 70m below ground might be rarely influenced by the simulated explosion. The process used in this study could be used to design the underground ammunition complex and analyse the stability of underground facilities being influenced by periodical vibration.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.22 no.1
• /
• pp.20-26
• /
• 2019

In this paper, we propose measurement based numerical resistivity model for low energy exploding foil initiator (LEEFI) of electronic safety and arming device(ESAD). A resistivity model describes a behavior of variable resistance in LEEFI by firing current. The previous resistivity model was based on high energy detonator applications as explosive bridge wire and exploding foil initiator. Therefore, to estimate the voltage, current, and burst time of LEEFI, a resistivity model suitable for LEEFI is needed. For the modeling of resistivity of LEEFI, we propose a specific action based equation which represents a behavior of LEEFI when firing current is applied. To verify the proposed model, we analyze a firing current transmission path to obtain parasitic impedance. We experimentally verify that the proposed resistivity model offers precise estimation for the behavior of variable resistance in LEEFI.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.6
• /
• pp.188-196
• /
• 2021

For the tactical vehicles operated by the Korean army, the hub-reduction portal axle was applied considering Korea's topographical characteristics. Hub-reduction was applied to a Korean military vehicle to increase the vehicle body to secure ground clearance and improve the driving capability on rough roads, such as unpaved and field land by increasing the torque. The Korean military is operating tactical vehicles after various performance tests, including durability driving, but wheel damage occurred in one of the vehicles operating in the front units. Failure analysis revealed many damaged parts, including the hub, making it difficult to determine the cause. Therefore, an analysis of the failure occurrence mechanism for each damaged part was conducted, which confirmed that the cause of wheel breakage was a hub. Furthermore, the root cause of the hub breakage was a crack due to internal pores and foreign matters. In addition, a realistic improvement plan that can be applied throughout the design, manufacture, and shipping stages was presented using the fishbone diagram analysis. The derived improvement plan was verified through unit performance tests, including CAE and actual vehicle tests, and by reflecting this, the driving safety of Korean tactical vehicles was improved. Finally, it is expected that the proposed method for analyzing the failure occurrence mechanism will be used as reference material when analyzing the quality problems of similar military vehicles in the future.

• Journal of Aerospace System Engineering
• /
• v.12 no.3
• /
• pp.38-44
• /
• 2018

Military aircraft may have fatigue cracks in structurally weak areas due to multiple factors such as the accumulation of flight time while perform various missions and unpredictable air conditions. As a fatigue crack progresses, there is a risk that the structure will be destroyed in extreme cases, which can have a significant impact on flight safety. In this study, a cracking phenomenon was observed during the periodic inspection the inner support of the fairing, which is installed to protect the connection between the wing and the body of the aircraft. Therefore, a study on a series of quality improvement processes for reformation was described. In order to identify the causes of cracks, pre-load generation occurrence during the wing assembly process was investigated and a fracture analysis was performed. Also, the design of the support structure was suggested in terms of preventing recurrence of cracks. The structural integrity was verified using a stress and fatigue life analysis.

• Strategy21
• /
• s.31
• /
• pp.220-250
• /
• 2013

South Korean national security strategy should be developed to effectively handle and counter increasing maritime threats and challenges. There are three major maritime threats South Korea faces today; maritime disputes on the EEZ boundary and Dokdo islet issues, North Korean threats, and international maritime security. Maritime disputes in the region are getting intensified and turned into a military confrontation after 2010. Now regional countries confront each other with military and police forces and use economic leverage to coerce the others. They are very eager to create advantageous de facto situations to legitimize their territorial claims. North Korean threat is also increasing in the sea as we witnessed in the Cheonan incident and Yeonpyoung shelling in 2010. North Korea resorts to local provocations and nuclear threats to coerce South Korea in which it may enjoy asymmetric advantages. The NLL area of the west sea would be a main hot spot that North Korea may continue to make a local provocation. Also, South Korean national economy is heavily dependent upon foreign trade and national strategic resources such as oil are all imported. Without an assurance on the safety of sea routes, these economic activities cannot be maintained and expanded. This paper argues that South Korea should make national maritime strategy and enhance the strength of naval forces. As a middle power, its national security strategy needs to consider all the threats and challenges not only from North Korea but also to maritime security. This is not a matter of choice but a mandate for national survival and prosperity. This paper discusses the importance of maritime security, changing characteristics of maritime threats and challenges, regional maritime disputes and its threat to South Korea's security, and South Korea's future security strategy and ways to enhance the role of naval forces. Our national maritime strategy needs to show middle and long term policy directions on how we will protect our maritime interests. Especially, it is important to build proper naval might to carry out all the roles and missions required to the military.

• Convergence Security Journal
• /
• v.14 no.3_1
• /
• pp.45-54
• /
• 2014

After the Cold War, obligations of nation are expanded to 'Comprehensive Security' that caring citizens' safety and welfare in addition to national defense. Major nations are competing to revolutionize their army to be prepared for various threats. Major nations, including United States and United Kingdom, are tend to adopting and using PMCs eagerly. The size of PMC market estimated around 70 billion euro and growing rapidly. Korea has to adopt PMCs for building military force and operating efficiency while driving 'Military Reform 2030'. Adopting PMCs in Korea can be considered as followings reflecting security situation. So, Korean army must consider implementing and adopting PMCs in order to building army force and attaining efficiency and preparing for the N orth Korean threat and various security risks.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.40 no.3
• /
• pp.456-464
• /
• 2016

A new combat uniform is improved for added combat safety with various functions such as survivability, battle conformity and a camouflage performance system. Camouflage performance is an important factor in terms of combat survivability since it makes identification difficult and provide security. The combat uniform is worn under extreme conditions (exposure to ultraviolet light, sweat and friction) and an excellent color fastness to repeated washing is required. In this study, we investigated the color management, durability and discoloration of new combat uniform fabric with a digital pattern for camouflage performance to provide preliminary color management data. We examined color differences between standard fabric and mass-produced combat uniform fabrics, color differences between each military supply contract firm and color changes in combat uniforms after 60 washing cycles. The slight color differences between standard fabric and mass-produced combat uniform fabrics were tolerable under quality criteria of Republic of Korea Ministry of National Defense. However, the differences between the military supply contract firms were recognizable to the naked eye and increased with repeated washing. Continuous research on color fastness under repeated washing and color management is required to standardize reliability from each military supply contract firm for the daytime performance of a combat uniform's camouflage.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.5 no.4
• /
• pp.692-698
• /
• 2001

The radio communications by SSB and VHF transceivers are still used very efficiently in coast stations and military base stations. The communication system by the conventional SSB and VHF transceivers between a coast station and a terminal is an one-to-one system. In this dissertation, however, the conventional one-to-one system is expanded to one-to-multiple systems. Then, frequencies can be used effectively for distress, urgency, safety traffic, and military communications. An ICS has been proposed and added, in this dissertation, to the conventional SSB and VHF communication systems, which can realize one-to- several terminal communications. The line switching system by the ICS is to be remote-controlled by ASK modulated PTT signals and audio signals. An ICS can change a connection between terminal and transceiver through a circuit switching system at any time. For this purpose, the author has researched and developed a ASK transmission system, ICS system, control algorithm, multiprocessor system, and moni-toring system. As a conclusion, the developed line switching control systems and equipments can be used effectively for maritime communication, military communication, fishery communication, etc.