• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 추계학술대회 논문집
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• pp.566-573
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• 1999

This paper is the result of sensitivity analysis of derailment with respect to the selected suspension elements for the rail vehicle. Derailment phenominon has been explained by the derailment quotient. Thus, the sensitivity of derailment is suggested by a response surface model(RSM) which is a functional relationship between derailment quotient and characteristics of suspension elements. To summarize generation of RSM, we can introduce the procedure of sensitivity analysis as follows. First, to form a RSM, a experiment is performed by a dynamic analysis code, VAMPIRE according to a kind of the design of experiments(DOE). Second, RSM is constructed to a 1$\^$st/ order polynomial and then main effect fators are screened through the stepwise regression. Finally, we can see the sensitivity level through the RSM which only consists of the main effect factors and is expressed by the liner, interaction and quadratic effect terms.

• 대한조선학회논문집
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• 제42권6호
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• pp.631-636
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• 2005

One and three dimensional whipping response analyses of a naval surface combatant subjected to an underwater explosion bubble pulse were carried out to compare the efficiency and accuracy according to the modeling methods. In 1-D analysis, program UNDEXWHIP developed by KIMM was used, which is based on the thin-walled Timoshenko's beam theory and on the modal analysis method using wetted vibratory modes of the hull girder. In 3-D analysis, three finite element models were suggested using LS-DYNA/USA code, such as 3-D beam model considering geometric shape of wetted side shell, coarse and fine 3-D F.E. models. Through the comparison of results from the 1-D and 3-D analyses, it could be confirmed that 1-D analysis result is in good agreement with 3-D analysis ones, and that fine 3-D F.E. model, shock analysis one, is also used both in the shock response and whipping response analyses for the analyst effort and time savings.

• Journal of Mechanical Science and Technology
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• 제20권4호
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• pp.533-544
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• 2006

The amplitude and phase lag of surface deformation were determined for a compliant coating under the action of turbulent pressure fluctuations. For this purpose, pressure fluctuations were measured experimentally. The amplitude and duration of coherent wave train of pressure fluctuations were investigated using digital filtration. The transient response was calculated for stabilization of forced oscillations of the coating in approximation of local deformation. The response of coating was analyzed with considerations of its inertial properties and limited duration of coherent harmonics action of pressure fluctuations. It is shown that a compliant coating interacts not with the whole spectrum of pressure fluctuations, but only with a frequency range near the first resonance. According to the analysis, with increasing elasticity modulus of the coating material E, deformation amplitude decreases as 1/E, and dimensionless velocity of the coating surface decreases as $1/\sqrt{E}$. For sufficiently hard coatings, deformation amplitude becomes smaller than the thickness of viscous sublayer, while surface velocity remains comparable to vertical velocity fluctuations of the flow.

• Membrane and Water Treatment
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• 제1권1호
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• pp.49-60
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• 2010

In this study, response surface methodology (RSM) was performed in NF membrane process to evaluate the separation efficiency of membrane in the removal of salt and reactive dye by varying different variables such as pressure, temperature, pH, dye concentration and salt concentration. The significant level of both the main effects and the interaction were observed by analysis of variance (ANOVA) approach. Based on the statistical analysis, the results have provided valuable information on the relationship between these variables and the performances of membrane. The rejection of salt was found to be greatly influenced by pressure, pH and salt concentration whereas the dye rejection was relatively constant in between 96.22 and 99.43% regardless of the changes in the variables. The water flux on the other hand was found to be affected by the pressure and salt concentration. It is also found that the model predictions were in good agreement with the experimental data, indicating the validity of these models in predicting membrane performances prior to the real filtration process.

• Preventive Nutrition and Food Science
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• 제21권1호
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• pp.44-51
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• 2016

The objective of this study was to determine the factors responsible for the changed physiochemical properties of unpeeled shrimp treated in cold phosphate solution ($2{\sim}4^{\circ}C$) with the intervention of 4 factors: phosphate concentration, dipping time, rotation speed, and volume of brine solution. Response surface analysis was used to characterize the effect of the phosphate treatment on shrimps by running 33 treatments for optimizing the experiment. For each treatment, phosphate amount, moisture content, and weight gain were measured. The results showed that phosphate concentration is the most important factor than other factors for facilitating phosphate penetration in the meat of the shrimp and for getting the best result. The optimum condition of phosphate-treated shrimp in this study was 110 to 120 min dipping time, 500 to 550 mL brine solution for 100 g shrimp sample, and 190 to 210 rpm agitation speed. The studied conditions can be applied in fisheries and other food industries for good phosphate treatments.

• 대한화학회지
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• 제58권2호
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• pp.198-204
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• 2014

In this present study, bagasse based pulp and paper industry wastewater was treated under different operating conditions such as initial pH (6-8), temperature ($25-35^{\circ}C$) and contact time (3-7 days) by using Bacillus subtilis. Response surface methodology (RSM) coupled with Box-Behnken response surface design (BBD) was employed to investigate the effect of process variables on the responses such as turbidity, biological oxygen demand (BOD) and chemical oxygen demand (COD) removal. The experimental data were analyzed by Pareto analysis of variance (ANOVA) and the second order polynomial models were developed. Interactive effects of the process variables on the responses were studied using plotting 3D response surface contour graph and the optimum process conditions were found to be: initial pH of 7, temperature of $30^{\circ}C$ and contact time of 5 days. Under these conditions, removal efficiencies of turbidity, BOD and COD were found to be 85%, 93% and 80% respectively which are close agreement with real experiments. These results indicate that the treatment of bagasse based pulp and paper industry wastewater using Bacillus subtilis is an effective and novel technique.

• 한국식품조리과학회지
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• 제26권1호
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• pp.54-61
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• 2010

This study was performed to determine the optimal manufacturing conditions adding green laver, which has a rich aroma and unique taste, to Sulgidduk. The variables in green laver Sulgidduk production were amounts of green laver powder and water. Six sensory characteristics were used for sensory evaluations, including color, green laver flavor, green laver taste, moistness, softness, and elasticity. The optimal amounts of the powder and water were found to be 6.84 g for green laver powder and 31.08 g for water, satisfying a target sensory score (7.0/9.0) according to a response surface method. Sulgidduk with these optimal amounts of green laver and water was tasted by 118 consumers and showed a high acceptability score (6.94). Older consumers ($\geq$30 years old) preferred the color and flavor of green laver significantly more than younger consumers ($\leq$29 years old) did (p<0.01). Color analysis results of green laver Sulgidduk were significantly different in brightness, redness, and yellowness from those of Sulgidduk (control)(p<0.01). Texture analysis scores of green laver Sulgidduk were significantly lower than those of Sulgidduk (control) in hardness, adhesiveness, springiness, cohesiveness, gumminess, and chewiness, and they were significantly different in adhesiveness and chewiness (p<0.05).

• 한국정밀공학회지
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• 제28권11호
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• pp.1297-1308
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• 2011

The light-weight design of UTM (Urban Transit Maglev)-02 car-body frames are performed, based on initial configuration. The thicknesses of fourteen sub-structures are defined as design variables and the loading condition is considered according to weight of sub-structures, electronic and pneumatic modules and passengers. For efficient and robust process of design optimization, objective function and constraints are approximated by response surface approximation. Structural analysis is performed at some sampling points to construct the approximated objective function and constraints composed of design variables. Design space is changed to find many optimal candidates and best optimal design can be found eventually. The Matlab Optimization Toolbox is used to find optimal value and sensitivity analysis about each design variable is also performed.

• Wind and Structures
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• 제31권1호
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• pp.59-73
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• 2020

Wind fragility analysis (WFA) of concrete chimney is often executed disregarding temperature effects. But combined wind and temperature effect is the most critical limit state to define the safety of a chimney. Hence, in this study, WFA of a 70 m tall RC chimney for combined wind and temperature effects is explored. The wind force time-history is generated by spectral representation method. The safety of chimney is assessed considering limit states of stress failure in concrete and steel. A moving-least-squares method based dual response surface method (DRSM) procedure is proposed in WFA to alleviate huge computational time requirement by the conventional direct Monte Carlo simulation (MCS) approach. The DRSM captures the record-to-record variation of wind force time-histories and uncertainty in system parameters. The proposed DRSM approach yields fragility curves which are in close conformity with the most accurate direct MCS approach within substantially less computational time. In this regard, the error by the single-level RSM and least-squares method based DRSM can be easily noted. The WFA results indicate that over temperature difference of 150℃, the temperature stress is so pronounced that the probability of failure is very high even at 30 m/s wind speed. However, below 100℃, wind governs the design.

• Structural Engineering and Mechanics
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• 제9권1호
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• pp.69-88
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• 2000

A relatively simple model of a buried structure response to a surface loading that can simulate a possible opening and closure of a gap between the soil and the structure is presented. Analysis of the response of small and medium scale buried roof slabs under surface impulsive loading shows that the model's predictions are in fairly good agreement with the experimental results. Application of the model to a study case shows the relative influence of system parameters such as, the depth of burial, the arching coefficient, and the roof thickness, on the interface pressure and on the roof displacement. This model demonstrates the effect of a gap between the structure and the soil. The relative importance of including a gap opening and closure in the analysis is examined by the application of the model to a study case. This study results show that the deeper the depth of burial, the longer the gap duration, and the shorter the duration of the initial interface impact, while the higher the soil's shear resistance, the higher the gap duration, and the shorter the initial interface impact duration.