• Journal of Radiation Protection and Research
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• v.16 no.2
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• pp.41-54
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• 1991

This paper aimed to analyse dose sensitivity to the controllable parameters of indoor radon $(^{222}Rn)$ and its decay products (Rn-D) by applying the input~output linear system theory. Physical behaviors of $^{222}Rn\;&\;Rn-D$ were analyzed in terms of $(^{222}Rn)$ gas -generation, -migation and -infiltration to indoor environments, and the performance output-function, i. e. mean dose equivalent to Tracho-Bronchial (TB) lung region, was assessed to the following extented ranges of the controllable paramenters; a) the ventilation rate $constant({\lambda}_v)\;:\;0{\sim}50[h^{-l}].\;b)$ the attachment rate $constant({\lambda}_a)\;:\;0{\sim}500[h^{-l}].\;c)$ the unattached-deposition rate constant (${\lambda}^u_d)\;:\;0-50[h-l]$. A linear input-output model was reconstructed from the original models in literatures, as follows, which was modified into the matrices consisting of 111 nodal equations; a) indoor $^{222}Rn\;&\;Rn-D$ Behaviour; Jacobi-Porstendoerfer-Bruno model.

• Earthquakes and Structures
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• v.13 no.1
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• pp.59-66
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• 2017

Modern seismic codes rely on performance-based seismic design methodology which requires that the structures withstand inelastic deformation. Many studies have focused on the inelastic deformation ratio evaluation (ratio between the inelastic and elastic maximum lateral displacement demands) for various inelastic spectra. This paper investigates the inelastic response spectra through the ductility demand ${\mu}$, the yield strength reduction factor $R_y$, and the inelastic deformation ratio. They depend on the vibration period T, the post-to-preyield stiffness ratio ${\alpha}$, the peak ground acceleration (PGA), and the normalized yield strength coefficient ${\eta}$ (ratio of yield strength coefficient divided by the PGA). A new inelastic deformation ratio $C_{\eta}$ is defined; it is related to the capacity curve (pushover curve) through the coefficient (${\eta}$) and the ratio (${\alpha}$) that are used as control parameters. A set of 140 real ground motions is selected. The structures are bilinear inelastic single degree of freedom systems (SDOF). The sensitivity of the resulting inelastic deformation ratio mean values is discussed for different levels of normalized yield strength coefficient. The influence of vibration period T, post-to-preyield stiffness ratio ${\alpha}$, normalized yield strength coefficient ${\eta}$, earthquake magnitude, ruptures distance (i.e., to fault rupture) and site conditions is also investigated. A regression analysis leads to simplified expressions of this inelastic deformation ratio. These simplified equations estimate the inelastic deformation ratio for structures, which is a key parameter for design or evaluation. The results show that, for a given level of normalized yield strength coefficient, these inelastic displacement ratios become non sensitive to none of the rupture distance, the earthquake magnitude or the site class. Furthermore, they show that the post-to-preyield stiffness has a negligible effect on the inelastic deformation ratio if the normalized yield strength coefficient is greater than unity.

• Journal of the Korean Institute of Gas
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• v.24 no.4
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• pp.62-72
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• 2020

This study presents a methodology of history matching to evaluate the productivity of shale gas reservoir with high reliability and predict future production rate in the Horn-River basin, Canada. Sensitivity analysis was performed to analyze the effect of physical properties of shale gas reservoir on productivity. Based on the results, reservoir properties were classified into 4 cases and history matching were performed considering the classified 4 cases as objective function. The blind test was conducted using additional field production data for 3 years after the history matching period. The error of gas production rate in Case 1(all reservoir parameters), Case 2(influenced parameters for productivity), Case 3(controllable parameters), and Case 4(uncontrollable parameters) were 7.67%, 7.13%, 17.54%, and 10.04%, respectively. This means that it seems to be effective to consider all reservoir parameters in early period for 4 years but Case 2 which considered influenced parameters for productivity shows the highest reliability in predicting future production. The estimated ultimate recovery (EUR) of production well predicted using the Case 2 model was estimated to be 17.24 Bcf by December 2030 and the recovery factor compared to original gas in place (OGIP) was 32.2%.

• Nuclear Engineering and Technology
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• v.21 no.1
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• pp.18-31
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• 1989

To analyze the impact of air pollution control on electricity generation cost, a computer program was developed. POGEN calculates levelized discounted power generation cost including additional air pollution control cost for coal power plant. Pollution subprogram calculates total capital and variable costs using governing equations for flue gas control. The costs are used as additional input for levelized discounted power generation cost subprogram. Pollution output for Rue Gas Desulphurization direct cost was verified using published cost data of well experienced industrialized countries. The power generation costs for the year 2001 were estimated by POGEN for three different regulatory scenarios imposed on coal power plant, and by levelized discounted power generation cost subprogram for nuclear power. Because of uncertainty expected in input variables for future plants, sensitivity and uncertainty analysis were made to check the importance and uncertainty propagation of the input variables using Latin Hypercube Sampling and Multiple Least Square method. Most sensitive parameter for levelized discounted power generation cost is discount rate for both nuclear and coal. The control cost for flue gas alone reaches additional 9-11 mills/kWh with standard deviation less than 1.3 mills/kWh. This cost will be nearly 20% of power generation cost and 40% of one GW capacity coal power plant investment cost. With 90% confidence, the generation cost of nuclear power plant will be 32.6-51.9 mills/kWh, and for the coal power plant it will be 45.5-50.5 mills/kWh. Nuclear is favorable with 95% confidence under stringent future regulatory requirement in Korea.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.2
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• pp.369-377
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• 2008

Though the Hough transform(HT) is a well-known method for detecting analytical shape represented by a number of free parameters, the basic property of the HT, the one-to-many mapping from an image spare to a Hough space, causes the innate problem, the sensitivity to noise. This basic problem also deteriorates the quality of detected lines and makes the detected line deviated from the real one or generates some bogus, multiple lines where only one real line exists. The size of Hough space also affects the quality of detected lines. In this paper, we analyzed the line distortions in the traditional Hough transform and showed that the distortions are relieved in the edge strength Hough transform(ESHT), which is a modified HT. However the usage of expanded edge and edge strength in ESHT can cause some new line distortions which do not exist in the HT. These new ones can be solved by a proper setting of decreasing and broadening parameter values and the optimal values can be determined only by some pre-determined values. We also illustrated several examples to show the distortion-decreasing property of ESHT.

• Journal of the Korea Society of Computer and Information
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• v.18 no.12
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• pp.197-205
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• 2013

In this study, we developed a program of optimizing stand-level carbon stock using a stand-level yield model and the Simulated Annealing (SA) heuristic method to derive a optimized forest treatment solution. The SA is one of the heuristic algorithms that can provide a desirable management solution when dealing with various management purposes. The SA heuristic algorithm applied 'thermal equilibrium test', a thresholds approach to solve the phenomenon that does not find an optimum solution and stays at a local optimum value during the process. We conducted a sensitivity test for the temperature reduction rate, the major parameter of the thermal equilibrium test, to analyze its influence on the objective function value and the total iteration of the optimization process. Using the developed program, three scenarios were compared: a common treatment in forestry (baseline), the optimized solution of maximizing the amount of harvest(alternative 1), and the optimized solution of maximizing the amount of carbon stocks(alternative 2). As the results, we found that the alternative 1 showed provide acceptable solutions for the objectives. From the sensitivity test, we found that the objective function value and the total iteration of the process can be significantly influenced by the temperature reduction rate. The developed program will be practically used for optimizing stand-level carbon stock and developing optimized treatment solutions.

• Geophysics and Geophysical Exploration
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• v.8 no.1
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• pp.26-33
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• 2005

Inversion of multi-mode surface-wave phase velocity for shallow engineering site investigation has received much attention in recent years. A sensitivity analysis and inversion of both synthetic and field data demonstrates the greater effectiveness of this method over employing the fundamental mode alone. Perturbation of thickness and shear-wave velocity parameters in multi-modal Rayleigh wave phase velocities revealed that the sensitivities of higher modes: (a) concentrate in different frequency bands, and (b) are greater than the fundamental mode for deeper parameters. These observations suggest that multi-mode phase velocity inversion can provide better parameter discrimination and imaging of deep structure, especially with a velocity reversal, than can inversion of fundamental mode data alone. An inversion of the theoretical phase velocities in a model with a low velocity layer at 20 m depth can only image the soft layer when the first higher mode is incorporated. This is especially important when the lowest measurable frequency is only 6 Hz. Field tests were conducted at sites surveyed by borehole and PS logging. At the first site, an array microtremor survey, often used for deep geological surveying in Japan, was used to survey the soil down to 35 m depth. At the second site, linear multichannel spreads with a sledgehammer source were recorded, for an investigation down to 12 m depth. The f-k power spectrum method was applied for dispersion analysis, and velocities up to the second higher mode were observed in each test. The multi-mode inversion results agree well with PS logs, but models estimated from the fundamental mode alone show f large underestimation of the depth to shallow soft layers below artificial fill.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.1
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• pp.43-50
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• 2021

A Leg Mating Unit (LMU) is a device utilized during the float-over installation of offshore structures that include hyperelastic pads and mating part. The hyperelastic pads absorb the loads, whereas the mating part works as guidance between topside and supporting structures during the mating sequence of float-over installation. In this study, the design optimization of an LMU for the float-over installation of floating-type offshore structures is conducted to enhance the performance and to satisfy the requirements defined by classification society regulations. The initial dimensions of the LMU are referred to the dimensions of those used in fixed-type float-over installation because only the location and the number of LMUs are known. The two-parameter Mooney-Rivlin model is adopted to describe the hyperelastic pads under given material parameters. Geometric variables, such as the thickness, height, and width of members, as well as configuration variables, such as the angle and number of members, are defined as design variables and are parameterized. A sampling-based design sensitivity analysis based on latin hypercube sampling method is performed to filter the important design variables. The design optimization problem is formulated to minimize the total mass of the LMU under maximum von Mises stress and reaction force constraints.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.20 no.2
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• pp.92-101
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• 2015

We investigated cause of non-outbreak of Cochlodinium polykrikoides blooms in the western coast of Jaran Bay during summer, 2013, based on the species competition among C. polykrikoides and Skeletonema sp. using a mathematical model. As a result of the model simulation where the nutrient conditions in Jaran Bay was applied during summer, the cell density of Skeletonema sp. was higher than that of C. polykrikoides. In the sensitivity analyses by doubling and halving the parameters, any parameter had little effect on the cell density of C. polykrikoides. The cell density of Skeletonema sp. was significantly affected by changes in the parameter values. These results indicated that the growth of C. polykrikoides could be unaffected by rapidly changing environments. However, the growth of Skeletonema sp. may have been promoted by the changing nutrient supply of coast environments. Therefore, C. polykrikoides might have been suppressed by diatom blooms, such as Skeletonema sp., in changing nutrient supply condition of Jaran Bay.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.6
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• pp.760-768
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• 2004

The present study was undertaken to evaluate the accuracy of ultrasonography in early pregnancy diagnosis in goats. Ultrasonographic scanning with real time B-mode ultrasound machine having 5 MHz linear array transducer was performed on gravid uterus (n=24) obtained from slaughterhouse (Group I). Crown rump length (CRL) measured by ultrasound was found significantly different (p<0.05) with actual CRL measured after dissection in early pregnancy. However, age predicted by ultrasound through the measurement of CRL was found highly correlated (r=0.92) with age measured after dissection through CRL and the weight of fetus. Ages predicted by ultrasound through the measurement of trunk diameter (TD) and uterine diameter (UD) and ages measured after dissection were found highly and equally correlated (r=0.98) and did not differ significantly. Data from six does synchronized (Group II) with PGF2$\alpha$ (Estrumate) at 11 days apart were collected through ultrasound from 17 to 42 days post breding. The correlation between CRL and gestational age was high (r=0.97) in day 30 to 42 post breeding. A high coefficient of correlation (r=0.98) was also observed between predicated age by ultrasound and actual age calculated after kidding. The correlation between CRL and gestational age by the formula Y=(a+bX) i.e. Y=24.42+0.39 X where Y=gestational age and X=CRL, was recorded very high (r=0.99). Accuracy of ultrasonography was lowest on day 17 to 19 (66%) and reached 100% on day 34. Data from 30 does (group III) randomly subjected to only one time ultrasounds scanning to assess the accuracy of pregnancy diagnosis were also obtained. Ages predicted by TD and UD measurements were observed to be non-significantly different with actual age obtained after kidding and correlation between ages predicted by TD and UD measurement with actual age after kidding was found equally and highly correlated (r=0.98). The operator's accuracy in the whole experiment including all three groups was found to be 92%. The sensitivity was 93% and specificity was 86%. From the present study, it was observed that CRL was the most reliable parameter to find out gestational age in early pregnancy and the new formula derived was found very accurate to find out gestational age. TD and UD were also found to be equally reliable parameter to find out gestational age in mid and late stage of pregnancy through ultrasonography. It was concluded that ultrasonography by real time B mode with 5 MHz transrectal transducer was found to be reliable, safe and accurate and practicable means in diagnosing early pregnancy diagnosis as early as 25 days post breeding.