• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.277-278
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• 2018

Improvement of insulation performance of buildings is a major part. Adiabatic method The adiabatic method minimizes the heat loss of the building. External insulation uses insulation to prevent fire. Ambient air hazards are less prone to fire. When a fire occurs, a phenolic pattern is formed and bond strength with the wall increases. EPS insulation and phenol foam were used to compare external heat transfer and external heat transfer. The heat transfer properties of phenolic foam and styrofoam were evaluated as follows. In the mortar and styrofoam structure, the problem of styrofoam reaching the burning point occurred before the collapse of the mortar, and the phenol foam had a problem in that when the direct fire was continued on the phenol foam. The characteristics of continuous infiltration appeared. In the case of mortar and phenol foam + styrofoam, the heat penetrated into the interior due to the shrinkage due to the shrinkage of the carbon screen on the phenol foam. However, when reinforced with glass mesh on the outer surface, And to reduce infiltration.

• Special Issue of the Society of Naval Architects of Korea
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• 2006.09a
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• pp.89-96
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• 2006

The objective of this paper is to find out a reasonable method for docking analysis of ships. The characteristics of reaction force distribution under docking condition are investigated by carrying out parametric study. To assess the allowable reaction force on keel block from structural strength point of view, two kinds of structural assessment methods are proposed in accordance with expected collapse pattern. In order to verify the proposed method, linear buckling and elasto-plastic large deflection analyses of typical double bottom structure are carried out and the results are compared.

• Structural Engineering and Mechanics
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• v.22 no.2
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• pp.169-184
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• 2006

A close form solution of the maximum deflection for cracked columns with rectangular cross-sections was developed and thus the elastic buckling behavior and ultimate bearing capacity were studied analytically. First, taking into account the effect of the crack in the potential energy of elastic systems, a trigonometric series solution for the elastic deflection equation of an arbitrary crack position was derived by use of the Rayleigh-Ritz energy method and an analytical expression of the maximum deflection was obtained. By comparison with the rotational spring model (Okamura et al. 1969) and the equivalent stiffness method (Sinha et al. 2002), the advantages of the present solution are that there are few assumed conditions and the effect of axial compression on crack closure was considered. Second, based on the above solutions, the equilibrium paths of the elastic buckling were analytically described for cracked columns subjected to both axial and eccentric compressive load. Finally, as examples, the influence of crack depth, load eccentricity and column slenderness on the elastic buckling behavior was investigated in the case of a rectangular column with a single-edge crack. The relationship of the load capacity of the column with respect to crack depth and eccentricity or slenderness was also illustrated. The analytical and numerical results from the examples show that there are three kinds of collapse mechanisms for the various states of cracking, eccentricity and slenderness. These are the bifurcation for axial compression, the limit point instability for the condition of the deeper crack and lighter eccentricity and the fracture for higher eccentricity. As a result, the conception of critical transition eccentricity $(e/h)_c$, from limit-point buckling to fracture failure, was proposed and the critical values of $(e/h)_c$ were numerically determined for various eccentricities, crack depths and slenderness.

• Journal of the Korean GEO-environmental Society
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• v.18 no.5
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• pp.35-43
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• 2017

It is a method of suppressing back ground subsidence by re-injecting groundwater back to the target ground and recovering the underground water level. In order to analyze the subsidence of the back ground due to maintaining the underground water level, indoor model experiments were conducted. Through this study, the factors influencing on the groundwater and the tendency of subsidence back ground by experiments were analyzed and the effect of ground subsidence by reinfusion of groundwater was also investigated. As a result of the subsidence analysis with considering only the influence of the underground water level, the settlement of the ground occurs as the underground water level at the time of ground excavation goes down. The closer to the back of the retaining wall, the maximum settlement occurred. Moreover, it was analyzed that the influence distance where subsidence occurs from retaining wall to the point of about 1.8 H on the basis of the ground collapse. The most effective location of water reinjection is the closet location to the back of braced-cut wall for reducing the groundwater down and also minimizing the ground settlement.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.05a
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• pp.245-248
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• 2006

A particle filter is one of the most famous filters. The reason why the particle filter is widely used is that particle deals with the state estimation problem for not only linear models with Gaussian noise but also the non-linear models with non-Gaussian noise and it receives great attention from many engineering fields. In the point of view state estimator, particle filter is feedforward observer. According to the characteristic of dynamic system, the feedforward observer can estimate real state. However, the speed of convergence of feedforward observer between the actual state and the estimated state cannot be satisfied. Since the particle filter is a sort of feedforward observer, the convergence speed of particle filter is slow, and the particle filter cannot estimate actual state like particle collapse problem. In order to overcome the limitation of particle filter as a kind of feedfoward estimator, we propose a new particle filter which has feedback term, called particle filter with feedback. Our proposed method is analyzed theoretically and studied by computer simulation. Comparisons are made with other filtering mehod.

• Journal of the Korean Society of Safety
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• v.25 no.2
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• pp.47-54
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• 2010

This paper presents a simple and efficient two-dimensional rigid-body-spring network model able to accurately estimate the fractural behavior of civil fiber reinforced pavements. The proposed rigid-body-spring network model, denoted as RBSN model, considers civil fiber reinforcing materials using the beam elements and link spring elements. The RBSN method is able to model collapse due to asphalt crushing and civil fiber slip. The RBSN model is used to predict the applied load-midspan deflection response of civil fiber retrofitted asphalt specimen subjected to the three-point bending. Numerical simulations and experimental measurements are compared to based on tests available in the literature. The numerically simulated responses agree significantly with the corresponding experimental results until the maximum load. However, It should be mentioned that, in order to more accurately predict the postpeak flexural behavior of the civil fiber retrofitted asphalt pavement, development of the advanced model to simulate the slip relationship between civil fiber and asphalt is required.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.644-648
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• 2004

In the present study were examined numerically and experimentally the off-design performance characteristics on an axisymmetric plug nozzle with variable throat area. In this nozzle concept, its throat area can be changed by translating the plug into the axial direction. First, a mixed-expansion plug nozzle, in which two expansion parts are arranged both inside and outside, was designed by means of the method of characteristics. Second, the CFD analysis was verified by the cold-flow wind tunnel test. Third, its performance characteristics were evaluated over a wide range of pressure ratio from half to double throat area through the design point, using the CFD code verified by the wind tunnel tests. It was made clear from the study that not so critical thrust efficiency losses were found and the maximum thrust efficiency loss was at most approximately 5 % under off-design conditions without external flow. This result shows that a plug nozzle can give the altitude compensation even under off-design geometry operations. However, shock waves were observed in the inner expansion part under the doubled throat area operation and thus some thermal problems may be caused on the plug surface. Furthermore, collapse of cell structure on the plug surface was observed with external flow (around Mach number 2.0) as it became lower pressure ratio below the design point and the fact may result in big efficiency loss regardless of geometrical configuration.

• Computational Structural Engineering
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• v.1 no.2
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• pp.101-109
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• 1988

The evaluation of the system reliability is generally quite difficult and costly as the structure becomes large and complex, especially when it is subjected to multiple time varying loads, and for redundant structures which have many possible modes of failur, e.g., system collapse through the formation of plastic hinge mechanisms. In reality most loadings acting on the structures are random in intensity as well as in occurrence time and duration. To include the load variability in time, the loads are described in terms of stochastic processes. Based on a tri-modal upper bound, a point estimate for the system reliability has been developed for more accuracy without extensive computational effort. This tri-modal point estimate also ensures the continuity of the system reliability function, which is a necessary condition in many nonlinear programming techniques. In addition, the Load Coincidence method, by which the combined effect of time varying loads are taken into account, has been modified to suitable for cases with an always-on load.

• The Korean Journal of Pain
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• v.11 no.2
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• pp.220-225
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• 1998

Background: The patients of facial hyperhidrosis have been known that they had much difficulties in interpersonal relationships and social activities due to excessive hidrosis when they were in stress, hot weather, or having meals. Previous drug therapy and stellate ganglion block have only temporary effects. The surgical method, $T_1$ sympathetomy has the risk of Hornor's syndrome. For that reasons, the sympathicotomy of proximal and distal portions of $T_2$ sympathetic ganglion with electroresectoscope used in transurethral resection seemed to be appropriate procedure, and we would like to report the results of our procedure. Method: Under the general anesthesia with semi-sitting position, and the portal was made through the small incision along the upper border of the 4th rib at the crossing point of mid-axillary line. After the partial collapse of lung by insufflation of 300 to 500 ml of $CO_2$, $T_2$ sympathetic ganglion was identified and resected proximally and distally with electro-cauterization. Finally the lung was expanded by limiting flow until the airway pressure reached 30 to 40 cm$H_2O$, and the wound was closed after removal of electroresectoscope. Result: There was no postoperative complication requiring surgical interventions. The facial sweating was stopped immediately after the operation and all the patients appeared to be satisfied. Conclusion: $T_2$ sympathicotomy with TUR electroresectoscope is thought be the minimal invasive and highly successful method in the treatment of facial hyperhidrosis. But longer terms follow-up will be needed to prove this result.

• Journal of Dental Rehabilitation and Applied Science
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• v.19 no.2
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• pp.115-124
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• 2003

One of the important things in the full mouth reconstruction is the determination of therapeutic position. Centric jaw relation is used as a therapeutic position for the full mouth reconstruction. There are several techniques associated with recording this position. Five clinically acceptable techniques are as follows: 1) Swallowing or free closure, 2) Chin point guidance, 3) Bimanual method 4) Myo-monitor technique, 5) Anterior deprogrammer. Centric relation obtained utilizing the anterior acrylic resin platform in this case. Another important thing in full mouth reconstruction is provisional restoration. Provisional restorations are an excellent diagnostic instrument, especially in full remain esthetics, phonetics, function, parafunction, and dysfunction after evaluation and acceptance through clinical trial with the provisional restorations should be accurately transferred to the final restorations to ensure the same clinical success. Especially, anterior guidance should be accurately transferred to the final restorations. An accurate anterior guidance is critical for optimal esthetics, phonetics, comfort, function, stress minimization, and longevity of teeth and restorations. To record optimum anterior guidance, customized anterior guide table is used in this case. Considering previously mentioned points, we did successive treatment. And it resulted in a better situation esthetically and functionally. Followings are what we cared in treating a patient in this case. 1) Accurate centric relation recording 2) Accurate transference of anterior guidance to the final restorations.