• Fire Science and Engineering
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• v.12 no.2
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• pp.29-42
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• 1998

The use of computer supported fire safety engineering calculations has grown significantly in recent years and will be increased rapidly. In this study, in order to examine for fire dynamics of the enclosed compartment with window glass(3mm, 4mm thickness) when the window glass breaks, we conducted numerical computer simulations about foam sofa fire with the zone type computer mode, FASTLite package(version 1.1.2) and the Berkeley algorithm for breaking window glass in a compartment fire, BREAK1 program (version 1.0). The analysis of the results in this paper shows that there are differences of fire dynamics between open-or enclosed-state compartment fire and the enclosed compartment fire with window glass breaking. It is also shown in this study that backdraft phenomenum occurs due to accumulated unburned combustible fuel when the glass of 4mm thickness breaks, and that temperature differences between the inner-and outer-surfaces of 3mm and 4mm thick glasses are appreciable. This study will help fire fighter to establish fire suppression or occupant's refuge strategies and fire safety engineer to enhance simulation techniques about the five dynamics of compartment fire.

• Fire Science and Engineering
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• v.26 no.2
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• pp.17-31
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• 2012

Regarding the landslide that took place around 00:08 on July 27, 2011, in a village in the city of Chuncheon (Sanjidanggol, Majeoksan, Cheonjeon-ri, Sinbuk-eup, Chuncheon-city, Gangwon-province), this paper surveyed fire-fighting officers who were injected into the site to rescue the disaster, thereby determining the problems surrounding the initial fire-fighting response and improvement measures. As a result, specialist education of volunteer fire-fighters and utilization, improvement measures included the early response ability enhancement of and cooperation between relevant agencies, the strengthening of specialist education about landslide response, the strengthening of situation management and field command system, the installation and operation of speedy field emergency infirmary, the operation of an appropriate volunteer waiting facility, the operation of an appropriate control lines, appropriate control of media, a sufficient securing of individuals' rescue equipment and fuel for heavy equipment, the provision of sufficient portable radios and chargers, the securing of fire-fighting budget thereof.

• Journal of the Korea Convergence Society
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• v.9 no.10
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• pp.1-6
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• 2018

This paper describes the azimuth accuracy of correlative interferometer direction finder on a scaled down airplane model. When the antennas are placed on the bottom of an airplane, reflection signals caused by an aircraft structure are arise and caused an azimuth error. In this paper, the F-16 fighter scale-down model was made to 5:1, and five antennas were placed on the bottom of the model. The accuracy was made by numerically analyzing the phases of the radio waves received by the five antennas when the signal of emitter was transmitted on $0-360^{\circ}$ azimuth angles. The azimuth error of the correlative interferometer direction finder on the model was measured to be less than $1.0^{\circ}$ when SNR was larger then 3dB, and it could be very useful for the design of the direction finder on airplane.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.8
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• pp.759-765
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• 2016

The PTO (Power Take-Off) shaft for aircraft, with welded construction using multiple thin membranes, was developed in the 1950s to improve the elasticity of the part. As it is lightweight, stable at high speeds, and has good flexibility, it is used in most of the fighter aircraft. It connects the AMAD (aircraft mounted accessory drive) gearbox with the EMAD (engine mounted accessory drive) gearbox and transmits the rotational power between them. It operates in the high speed range of 10,000-18,000 rpm. In this study, the safety of the PTO shaft made of Ti alloy was investigated using finite element analysis, and the ability to transmit power was demonstrated through a high-cycle fatigue test conducted in a laboratory. Further, the life of the ball joints of the aircraft under high-cycle fatigue test conditions was predicted, and the wear characteristics were analyzed.

• Anxiety and mood
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• v.5 no.2
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• pp.89-95
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• 2009

Objective : This study examined changes in the depression, anxiety, and suicidal ideation among Air Force conscripts during their Basic Military Training. Methods : Study participants were 500 Air Force conscripts. The study reviewed participants' self-reports on depression, symptoms of anxiety, and suicidal ideation at weeks 2, 4, and 6 of their training. Results : At weeks 2 and 4 of training, participants' mean BDI, BAI, and SCL-90-R depression and anxiety subscale scores were within the mild ranges. However, at week 6, those mean scores were in the normal ranges. The mean scores for the BDI, the BAI, and the depression and anxiety subscales of the SCL-90-R at weeks 2 and 4 were significantly elevated over the corresponding scores for week 6 (each F=8.78, df=2, p<0.01 ; F=22.16, df=2, p<0.01 ; F=11.08, df=2, p<0.01 ; F=3.42, df=2, p<0.05). Suicidal ideation, revealed by the mean BSIS score, fell within the normal range (F=9.94, df=2, p<0.01) throughout the study period. Conclusions : These results suggest that conscripts' initial levels of psychological distress in the form of depression and anxiety are slightly elevated, but most adapt to this distress during basic training. Therefore, more attention must be paid to the early stages of conscripts' basic training in order to address these concerns.

• The Journal of the Korea Contents Association
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• v.12 no.1
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• pp.386-399
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• 2012

This study was carried out by practical method in a subjectivity study accessible in-depth, in sloughing off old habit of functional quantity analysis about policy of dental treatment. The perception pattern come out in this study were divided into four types in Q-methodology. The result is as follows ; it is divided into 1[(N=11) : Extension Policy Type], 2[(N=13) : Institutional Improvement Type], 3[(N=5) : Image Improvement Type], 4[(N=14) : Treatment Focus Type], 5[(N=5) : Efficient Access Type], 6[(N=10) : Developmental Demand Type]. There are four types of fire fighter images. In conclusion, this study is to ascertain acceptance behavior about Reception Type on policy of dental treatment ; to offer a developmental suggestion about it.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.4
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• pp.25-32
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• 2006

An advanced method of Relaxed Static Stability (RSS) is utilized for improving the aerodynamic performance of modern version supersonic jet fighter aircraft. The flight control system utilize RSS criteria in both longitudinal and lateral-directional axes to achieve performance enhancements and improve stability. The T-50 advanced trainer employs the RSS concept in order to improve the aerodynamic performance and the flight control law in order to guarantee aircraft stability. The longitudinal two modes are the short period with high frequency and the phugoid mode with low frequency. The design goals of longitudinal control laws is concerned with the short period damping and frequency optimization using lower order equivalent system and utilizing the requirement of MIL-F-8785C. Analysis of short period mode has been and continues to be performed This paper addresses the analysis of aircraft phugoid node characteristics such as damping, natural frequency, and analysis of aircraft pitch motion that impacted by angle of attack limiter and auto pitch attitude control law.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.6
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• pp.83-91
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• 2006

An advanced method of Relaxed Static Stability (RSS) is utilized for improving the aerodynamic performance of modern version supersonic jet fighter aircraft. The flight control system utilizes RSS criteria in longitudinal axis to achieve performance enhancements and improve stability. The flight control law of T-50 advanced trainer employs RSS concept in order to improve the aerodynamic performance and guarantee aircraft stability. The longitudinal center of gravity(X-c.g) varies as a function of external stores, fuel state and gear position. Shifts in X-c.g relate directly to longitudinal static margin in aircraft stability. This paper deals the maximum aft X-c.g for critical aircraft loadings and checks static margin limits using sensitivity such as damping, natural frequency, gain and phase margin. And nonlinear analysis was conducted for such as short period input. And also, this paper shows the T-50 aircraft stability based on the result of high angle of attack flight such as upright and inverted departure.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.8
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• pp.41-46
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• 2006

The capability for reconstructing impact forces of an aircraft wing using impact response functions and regularization methods were examined. The impact response function which expresses the relation between the structure response and the impact force was derived using the information on mass and stiffness data of a finite element model for the wing. Iterative Tikhonov regularization method and generalized singular value decomposition method were used to inverse the impact response function that was generally ill-posed. For the numerical verification, a fighter aircraft wing was used. Strain and deflection histories obtained from finite element analysis were compared with the results calculated using impact response functions. And the impact forces were reconstructed with the strain histories obtained from finite element analysis. The numerical verification results showed that this method can be used to monitor impact forces on aircraft structures.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.3
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• pp.93-100
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• 2006

Modern versions of supersonic jet fighter aircraft using a digital flight-by-wire flight control system design utilizes a control surface reconfiguration in order to guarantee the aircraft flight stability when a control surface is failed. The T-50 flight control laws are designed such that the surface reconfiguration mode controls the aircraft using non-failed control surfaces when one of the control surfaces is failed. In this paper, linear analysis and HQS(Handling Quality Simulator) pilot simulations are performed to analyze the flight stability and handling quality when the surface reconfiguration mode is engaged for aircraft landing configuration. It is found that the aircraft flight stability and handling quality is satisfied to level 1 requirements when the T-50 flight control law is changed to the surface reconfiguration mode.