• Tunnel and Underground Space
• /
• v.28 no.4
• /
• pp.304-324
• /
• 2018

Singapore government is strongly promoting the development and utilization of underground space in national level due to the nature of the city state which lacks the land. As well as conventional underground utilization in shallow depth such as metro and underground roads, large rock cavern utilization has been started after the successful completion of the underground ammunition depot in the rock, and Jurong Rock Cavern, the second large underground cavern project has just been completed. In this paper, after evaluating the conditions of the underground development in rock mass through the analysis of the geology of Singapore, the history and current status of underground development are examined. Several creative development plans from Singapore government such as underground reservoirs, underground automation logistics systems and underground warehouses storage etc. are introduced with technical issues. This paper also discusses the problems and issues related to the development of large underground space in rock mass in Singapore. It is expected that such active development of underground space in Singapore can give many opportunities and also challenges for rock engineering and industry in the future.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.24 no.6
• /
• pp.1285-1292
• /
• 2014

Ministry of National Defense made has set a standard regulations and detail to classify the revision of the military security and the plan to adjust or use those secrets. Moreover, the confidential management system with online secret process is operated by it. However, the study for management plan of stored secret data in these systems should be urgently required because the current regulation of military headquarter is different from present military situation so that it is not applicable up to now. This paper is focused on the Defense Ammunition Information Systems to find the proper way to deal with the secret data of the Defense Information Systems. The purpose is to describe the management plan for the secret data consistent with the current situation of the Military by study for the secret classification and case study. Therefore limitations are considered and solutions are finally suggested in this paper.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.18 no.5
• /
• pp.1-11
• /
• 2014

Sympathetic detonation (SD) of high explosives occurs when a detonating donor initiates neighboring acceptors. The present study focuses on the hydrodynamic simulation of one-on-one sympathetic detonation of 155 mm charge filled with PBXN-109. Both unbuffered and buffered SD configurations are performed while changing the distance between each charge, in order to investigate the detonation sensitivity to a donor initiation. The cause of a SD is by a shock impact for the unbuffered case at a close range, while at a distant range, blast fragment penetration is the primary cause. The buffers can reduce the incident sensitivity to a SD by reducing the strengths of shock wave and impinging fragments.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.12
• /
• pp.1-6
• /
• 2018

This study examined the quality improvement of printed circuit boards (PCBs) in relation to the power consumption for radar. The radar examined is currently in production and being used by the military. The PCB converts 28 V DC to 5 V DC but frequently malfunctions. Therefore, cause analysis was carried out. As a result, the power consumed by a certain communication IC was very high, and the heat generated by the high power consumption caused damage to the surrounding parts. Accordingly, it was changed to an improved communication IC that meets all the radar system specifications. System tests were carried out for the changed communication IC to check the impact on the system, and environmental tests were performed, which proved that the performance required by the radar system is satisfactory. As a result of this improvement, there has been no history of failure in this PCB so far. Therefore, the quality of this PCB has been improved.

• Journal of the Korea Safety Management & Science
• /
• v.26 no.2
• /
• pp.23-31
• /
• 2024

In the military, ammunition and explosives stored and managed can cause serious damage if mishandled, thus securing safety through the utilization of ammunition reliability data is necessary. In this study, exploratory data analysis of ammunition inspection records data is conducted to extract reliability information of stored ammunition and to predict the ammunition condition code, which represents the lifespan information of the ammunition. This study consists of three stages: ammunition inspection record data collection and preprocessing, exploratory data analysis, and classification of ammunition condition codes. For the classification of ammunition condition codes, five models based on boosting algorithms are employed (AdaBoost, GBM, XGBoost, LightGBM, CatBoost). The most superior model is selected based on the performance metrics of the model, including Accuracy, Precision, Recall, and F1-score. The ammunition in this study was primarily produced from the 1980s to the 1990s, with a trend of increased inspection volume in the early stages of production and around 30 years after production. Pre-issue inspections (PII) were predominantly conducted, and there was a tendency for the grade of ammunition condition codes to decrease as the storage period increased. The classification of ammunition condition codes showed that the CatBoost model exhibited the most superior performance, with an Accuracy of 93% and an F1-score of 93%. This study emphasizes the safety and reliability of ammunition and proposes a model for classifying ammunition condition codes by analyzing ammunition inspection record data. This model can serve as a tool to assist ammunition inspectors and is expected to enhance not only the safety of ammunition but also the efficiency of ammunition storage management.

• Analytical Science and Technology
• /
• v.22 no.4
• /
• pp.285-292
• /
• 2009

It has been observed that, after long term storage, some ammunitions are misfired by tamping (combustionstopping) due to aging of the chemicals loaded in the ammunitions. Used in ammunitions are percussion powder which provides the initial energy, igniter which ignites the percussion powder, and a delay system that delays the combustion for a period of time. The percussion powder is loaded first, followed by the igniter and then the delay system, and the ammunitions explode by the energy being transferred in the same order. Tamping occurs by combustion-stopping of the igniter or insufficient energy transfer from the igniter to the delay system or the combustion-stopping of the delay system, which are suspected to be caused by low purity of the components, inappropriate mixing ratio, size distribution of particulate components, type of the binder, blending method, hydrolysis by the humidity penetrated during the long term storage, and chemical changes of the components by high temperature. Goal of this study is to find the causes of the combustion-stopping of the igniter and the delay system of the ammunitions after long term storage. In this study, a method was developed for testing of the combustion-stopping, and the size distributions of the particulate components were analyzed with field-flow fractionation (FFF), and then the mechanism of chemical change during long term storage was investigated by thermal analysis (differential scanning calorimetry), XRD (X-ray diffractometry), and XPS (X-ray photoelectron spectroscopy). For the ignition system, M (metal)-O (oxygen) and M-OH peaks were observed at the oxygen's 1s position in the XPS spectrum. It was also found by XRD that $Fe_3O_4$ was produced. Thus it can be concluded that the combustion-stopping is caused by reduction in energy due to oxidation of the igniter.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.11 no.2
• /
• pp.23-31
• /
• 2008

The configuration model of a ballute type RAID(Ram Air Inflated Decelerator) for reducing the high speed and high revolution of smart submuntion is designed and tested. Three dimensional incompressible turbulent flow computational fluid dynamic analysis for the assembly of ballute and submunition is performed and pressure distribution, velocity, and drag around the assembly is calculated. Aerodynamic characteristics of the ballute assembly such as air flow inside and outside of the ballute and pressure distribution is clearly shown and it's drag coefficient is computed. Trajectory analysis of the submunition is performed and is in good agreement with the descending trajectory data of experimental model tested.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.15 no.3
• /
• pp.58-65
• /
• 2016

This study analyzed the structural weld strength for a door hinge for a field artillery ammunition support vehicle. In order to determine the optimal conditions, we measured the modal analysis and analyzed the leg length of a rear door hinge. From these methods, we acquired the vibration frequency of normal mode and the optimal welding leg length conditions. It was possible to obtain a structural stability for a rear door hinge of the field artillery ammunition support vehicle. In the future, this should be used as a reference source for the weld strength analysis of high vibration and high weight structures for another welding system design.

• Journal of the military operations research society of Korea
• /
• v.30 no.1
• /
• pp.92-106
• /
• 2004

This is a case study which establishes effective ammo issue plan and determines ammo support capability by linking various situations about ammo issue with wargame simulation. Ammo function simulation model has been developed for this matter and it has been proven that the model has significant impact on type of round, parking space for magazine, number of workers and capacity of equipment, etc. during establishing ammo issue plan and determining ammo supply capability. Also, ammo support capability varies significantly depending on tactical damage and MOPP status, etc. ASP's tactical situation, such as magazine damage, MOPP status, type of issuing round, parking space for magazine, number of workers and capacity of equipment, can be reflected when preparing an effective wartime ammo working hour issuing plan for supplying ammo to units through studies results, so that the issuing plan can be realistic and actual.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2006.11a
• /
• pp.513-524
• /
• 2006

The ammunition allocation problem is a Multi-objective optimization(MOO) problem, maximizing fill-rate of multiple user troops and minimizing transportation time. Recent studies attempted to solve this problem by the prior preference articulation approach such as goal programming. They require that all the preference information of decision makers(DM) should be extracted prior to solving the problem. However, the prior preference information is difficult to implement properly in a rapidly changing state of war. Moreover they have some limitations such as heavy cognitive effort required to DM. This paper proposes a new ammunition allocation model based on more reasonable assumptions and uses an interactive MOO method to the ammunition allocation problem to overcome the limitations mentioned above. In particular, this article uses the GDF procedure, one of the well-known interactive optimization methods in the MOO liter-ature, in solving the ammunition allocation problem.