Purpose: When the SURION Aircraft operated in the fields, cracks are found in PU(polyurethane) Strip on main rotor blade. This study has been conducted to explain PU(polyurethane) Strip crack phenomenon of SURION main rotor blade and to propose useful solution of it by experimental method.
Methods: This study considered a lot of factor because the SURION is operated at severe environment. This study investigated the influence of temperature, thermal shock, paint and primer process, PU Strip material, primer material.
Results: The results of this study are as follows; The primer process was most excellent influence. The Application of primer having a brittleness caused by a crack of PU Strip. Other factors have influenced on the PU Strip, but they can not be controlled because they are related to the SURION's operating environment.
Conclusion: The Quality of PU Strip on SURION main rotor blade was improved through removing the primer process. Finally, the reliability of main rotor blade was guaranteed through improving the quality of PU Strip.

Purpose: In this study, the goal is to analyze this case to prevent the same accidents when using one-shot rifle.
Methods: Detailed analysis of damaged parts must first be made in order to determine the cause of the abnormal explosion. The cause of abnormal operation can be determined by analyzing the information of damaged components and the firing mechanism of the weapon step by step. Also we can refer to a statement of shooter, witness and accident scene situation. Based on this theory, cause of abnormal firing can be narrow down.
Results: Fracture of pin for fixing firing and latch is cause of abnormal operation of firing. Conclusion: It is deemed that periodic inspection and fundamental improvement of the structure are required to prevent the same accident as this.

Purpose: The purpose of this study was to resolve the Naval ship's Local Operation Panel(LOP) malfunction problems which caused by overheating in summer season and dispatching to equatorial regions.
Methods: Instead of using dual type heat insulation materials(consist with ceramic wool and glass wool), aerogel heat insulation materials were used for decreasing heat emissions from gas-turbine heat waste steam pipes passing water-jet- room. Experiment and Computational analysis of heat flow were conducted to analyze the internal room temperature changes.
Results: The results of this study are as follows; The aerogel heat insulation materials suppress heat emission more efficiently than dual type insulation materials. The cold surface temperature of insulation was far more decreased and internal room, LOP surface temperature also showed significant results too.
Conclusion: The substituted heat insulation materials appeared remarkable performance in decreasing room temperature that it could be used for suppressing the LOP overheatings and malfunctions.

Purpose: The purpose of this study is to improve the quality of the PGM system by improving the structure and production process of slip-ring rotary joint for radar. 
Methods: The improvement measures for each cause are established through failure analysis of broken items. Specifically, changing in the housing to improve the heating system. Changing the transportation method to prevent damage to equipment during transport. Changing work process of the attenuator ring to prevent damage. etc.
Results: The results of this study are as follows; improving the heating system reduces heat generated by the attenuator by about 7 degrees and obtain additional temperature margins. Reduction of defect rate because of adding X-band rotary joint run-out measurement test, ESS of slip-ring rotary joint and Transportation improvement(reinforced flight boxes, tube protection, etc). Getting stable VSWR values by improving work process of attenuator overheating due to a bad bonding process.
Conclusion: Through this study, improvements were made to slip-ring rotary joint that failed repeatedly for various reasons. As a result of the application of the improvements, the same fault does not occur until now, so we can see that the quality of PGM has improved.

Purpose: A main purpose is to increase the operational rate and reduce operating maintenance costs by Improving the durability of Blower of Military Armored Vehicle and Self-propelled Artillery. As a result, it is expected to improve the service quality of customers.
Methods: After analyzing the cause of the stop of the blower, the improvement plans were established and the effectiveness of each improvement plans were verified by testing.
Results: Mechanical, electrical and environmental factors affecting brush wear were reviewed, but it was difficult to specify the cause, which necessitated a review of the application of the BLDC motor.
Conclusion: After applying the BLDC motor to the blower, tests proved that the existing blower can be replaced. It is expected that this study will help improve the durability life of similar equipment that is applied with Brushed DC motors as well as blowers.

Purpose: The purpose of this paper is to improve quality for water infiltration to FCISA during military aircraft operation.
Methods: A series of troubleshooting studies were conducted to identify the root cause of the water infiltration and reproduce the defects through various simulation tests. And design improvement measures were derived, and countermeasures were taken to prevent recurrence of moisture inflow defects.
Conclusion: FCISA operates a very important role in the operation of military aircraft, and defects due to water infiltration are very fatal to flight safety. In this study, the root cause was identified and the design improvement to prevent recurrence was carried out through the failure investigation performed in this study, and the FCISA was improved so that the flight safety was not affected. The results of this study will be valuable back data that can be reflected in the design process through Lessons-Learned in the design phase of the aircraft that will be developed in the future.

Purpose: The purpose of this research is to develop defense quality evaluation model in order to improve the problem of private sector quality evaluation model and propose the total integrated defense quality management model which enables to evaluate not only large defense industry, but also small-medium industry.
Methods: This paper consider the characteristics on ISO 9001 Quality Management System, single PPM, PASS and defense quality and develop defense quality maturity model and index which enables to measure the current quality management level and characteristics and to evaluate operational characteristics in each maturity level for domestic defense industry.
Results: From 176 DQMS certified defense industry, the defense quality maturity level is 68,2, C grade. The large defense industry shows, 80.9, A grade; medium industry 69.7, C grade; small-medium industry shows 54.1, D grade. Through the classified types of industries, the current level of quality management of defense industries was diagnosed and the areas to be supplemented for the total quality management were identified.
Conclusion: Developed DQMI can be used as the basic information for spreading quality management activities in the defense industry by diagnosing the overall quality management of existing defense industries and quantifying the ambiguity of non-metric measurements and measurement standard that were presented as the threshold of the defense quality management system certification process.

Purpose: The purpose of this study is to overcome limitations of conventional studies that to predict Baltic Dry Index (BDI). The study proposed applications of Artificial Neural Network (ANN) named Long Short-Term Memory (LSTM) to predict BDI.
Methods: The BDI time-series prediction was carried out through eight variables related to the dry bulk market. The prediction was conducted in two steps. First, identifying the goodness of fitness for the BDI time-series of specific ANN models and determining the network structures to be used in the next step. While using ANN's generalization capability, the structures determined in the previous steps were used in the empirical prediction step, and the sliding-window method was applied to make a daily (one-day ahead) prediction.
Results: At the empirical prediction step, it was possible to predict variable y (BDI time series) at point of time t by 8 variables (related to the dry bulk market) of x at point of time (t-1). LSTM, known to be good at learning over a long period of time, showed the best performance with higher predictive accuracy compared to Multi-Layer Perceptron (MLP) and Recurrent Neural Network (RNN).
Conclusion: Applying this study to real business would require long-term predictions by applying more detailed forecasting techniques. I hope that the research can provide a point of reference in the dry bulk market, and furthermore in the decision-making and investment in the future of the shipping business as a whole.

Purpose: The purpose of this study is to analyze how the writing rules of the product user guide affect consumers' understanding of products and the prevention of product accidents.
Methods: We surveyed consumers to see how the writing rules of the product user guide help consumers to understand products and prevent product accidents. 
Results: We derived the importance, necessity, usability, and readability of the principle of making product manuals through analysis of previous research. Usability is the writing rule of the product user guide that the consumer has the most influence on the understanding of product use and the product accident.
Conclusion: It is necessary to make product user guide so that consumers can understand the function and safety of products by using video and various image media. Also, It is the obligation to explain all stages of the product and to communicate through the product user guide how to prevent the product accident step by step.

Purpose: We research on the efficient response surface methodology(RSM) design to develop a design space in Quality by Design(QbD). We propose practical designs for the successful construction of the design space in QbD by allowing different number of replicates at the box points, star points, and the center point in the rotatable central composite design(CCD).
Methods: The fraction of design space(FDS) plot is used to compare designs efficiency. The FDS plot shows the fraction of the design space over which the relative standard error of predicted mean response lies below a given value. We search for practical designs whose minimal half-width of the tolerance interval per a standard deviation is less than 4.5 at 0.8 fraction of the design space.
Results: The practical designs for the number of factors between two and five are listed. One of the designs in the list could be chosen depending on the experimental budget restriction.
Conclusion: The designs with box points replications are more efficient than those with the star points replication. The sequential method to establish a design space is illustrated with the simulated data based on the two examples in RSM.