• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.821-824
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• 2008

This paper presents a systematic approach for estimating material performance of concrete mixture design based on satisfaction curves developed from statistical evaluation of existing or newly obtained material property related data. In performance based material design (PBMD) method, concrete material used for construction of a structure is designed considering a structure's specified performance requirements based on its usage and characteristics such as environmental conditions, structure types, expected design life, etc.Satisfaction curves express the probabilities that one component of substrates (i.e., aggregate size, cement content, etc) of concrete mixture will sustain different criterion value for a given concrete mixture design. This study presents a statistical analysis method for setting up concrete material parameter versus concrete criterion relationships in the form of satisfaction curves and for estimating confidence bounds on these satisfaction curves. This paper also presents an analysis method to combine multiple satisfaction curves to form one unique satisfaction curve that can relate the performance of concrete to a single evaluating value. Based on several evaluated mixture design examples for various material properties, the validity of the proposed method is discussed in detail.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.9
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• pp.14-23
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• 1993

In this paper, we present analysis results of various intermodulation products (IMPs) evaluation methods previously proposed for nonlinear systems. The results indicate that out of these methods, Fuenzalida and Simbo's method is the best for efficient evaluation of IMPs. Also, we present a detailed mathematical analysis of IMP and show how to apply the equations related to IMP to actual program implementations with examples. In this paper, we newly introduce three methods to reduce the IMP calculation time and improve the accuracy of the outputs :1) TWTA curve fitting method by LS (Least Square), 2) IMP evaluation technique which is based on a look-up table 3) Gaussian spectral shaping for PSK signal instead of convolution. The IMP evaluation results obtained by the new approaches introduced in this paper resulted in a good match with the published outputs in the open literature and showed improved performance especially in the TWTA curve .

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.5891-5893
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• 2013

Incidence/mortality of liver cancer follow logistic curves because there is a limit reflecting the prevalence of hepatitis virus carriers in the cohort. The author fitted logistic curves to incidence/mortality data covering the nine five-year cohorts born in 1911-1955 of both sexes. Goodness-of-fit of logistic curves was sufficiently precise to be used for future predictions. Younger cohorts born in 1936 or later were predicted to show constant decline in incidence/mortality in the future. The male cohort born in 1931-35 showed an elevated incidence/mortality of liver cancer early in their lives supporting the previous claim that this particular cohort had suffered massive HCV infection due to nation-wide drug abuse in the 1950s. Declining case-fatality observed in younger cohorts suggested improved treatment of liver cancer. This study demonstrated that incidence/mortality of liver cancer follow logistic curves and fitted logistic formulae can be used for future prediction. Given the predicted decline of incidence/mortality in younger cohorts, liver cancer is likely to be lost to history in the not-so-distant future.

• Structural Engineering and Mechanics
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• v.85 no.6
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• pp.781-791
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• 2023

Lateral pressure plays a significant role in the stress-strain relationship of compressed concrete. Concrete's internal cracking resistance, ultimate strain, and axial strength are improved by confinement. This phenomenon influences the nonlinear behavior of reinforced concrete columns. Utilizing behavior factors to predict the nonlinear seismic responses of structures is prevalent in seismic codes, and this factor plays a vital role in the seismic responses of structures. This study aims to evaluate the confining action on the behavior factor of reinforced concrete moment resisting frames (RCMRFs) with shear walls (SWRCMRFs). To this end, a diverse range of mid-rise SW-RCMRFs was initially designed based on the Iranian national building code criteria. Second, the stress-strain curve of each element was modeled twice, both with and without the confinement phenomenon. Each frame was then subjected to pushover analysis. Finally, the analytical behavior factors of these frames were computed and compared to the Iranian seismic code behavior factor. The results demonstrate that confining action increased the behavior factors of SW-RCMRFs by 7-12%.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.11
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• pp.11-16
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• 1997

In the stroke sensitive shock absorber, the oil path is formed along the internal cylinder surface to make the oil flow during the piston's upper-lower reciprocation movement. In constrast with the conventional shock absorbesr which show one dynamic characteristic curve, stroke sensitive shock absorber shows two kinds of dynamic characteristics according to the stroke. In this study, in order to obtain more precise information about design and damping performance analysis, the analysis on the damping force generation process and dynamic behaviour characteristics of stroke sensitive shock absorber are performed by considering the valve characteristics.

• Journal of Korean Port Research
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• v.11 no.2
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• pp.281-294
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• 1997

Fatigue strength analysis is one of the most important themes of ship structure design, as fatigue damages are reported on ship structures even now. But these need basic research workes which will take time. The others are the problem to apply fatigue strength analysis in design and have to be investigated in parallel with basic researches. The one of major items in the latter is the critical damage factor to define with S-N curve for fatigue strength analysis of ship structure design.

• The Korean Journal of Quaternary Research
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• v.18 no.1 s.22
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• pp.31-39
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• 2004

The stable-unstable curve graph (S-U curve) and the ignition los curve graph (IL curve) for pollen composition and inorganic material content in three areas (namely, Kawadoi Basin, Moniwa-Takada moor, and Nenoshiroishi moor) were prepared to reconstruct the recurrence history of slope failure during the Holocene in Northeastern Japan. Through the S-U curve, a period with a high slope failure frequency of 5,600~4,670yrB.P. was identified in Kawadoi Basin, two of 6,390~5,070yrB.P. and 4,750~3,800yrB.P. in Moniwa-Takada moor, and three of 6,630~6,070yrB.P., 5,890~5,360yrB.P., and 5,000~4,650yrB.P. in Nenoshiroishi moor. Through the IL curve, a period with a high slope failure frequency of 5,600~5,140yrB.P. was identified in Kawadoi Basin, and two of 6,390~6,170yrB.P. and 4,750~2,840yrB.P. in Moniwa-Takada moor. Most of above-mentioned periods were included in the period of slope instability in precedent studies. However, the periods with high slope failure frequency in this study were rather different from those in precedent studies. The times and numbers associated with these periods in each study area also showed discrepancies. Accordingly, to achieve the above-mentioned purpose, more case studies must be performed to improve the reconstruction level of slope failure frequency, which could be explained through the analysis of pollen composition and inorganic material content.

• Journal of the Korean Society for Railway
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• v.13 no.2
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• pp.201-207
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• 2010

The replacement criterion of rail by accumulated passing tonnage was estimated by the bending fatigue life of rail. In order to estimate the bending fatigue life, it is basically needed to analyze bending fatigue behavior on the rail. In this study, the bending fatigue test were performed for 50kg/m and 60kg/m rails, and test specimens were distinguished by new and used rails and by the types of welded rail such as base material, thermite weld, and gas pressure weld. Also, this study analyzed the fractured surface, the position of initial crack and the bending fatigue behavior (S-N curve). Therefore, it evaluated S-N curve for welded rails according to the fracture probability. The result from this study might be used essential data in order to estimate the bending fatigue life of rail by the accumulated passing tonnage.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.4
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• pp.106-115
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• 2014

Until now, because a new product (or facility) launched in market has been retired from one year of age, we can have had ASL by stub-curve method by Iowa curve. Recently, many innovative products with important role in market like display and solar-cell etc. are more durable and, what are better, they have the constant variance in ASL because of their good quality. Of course, there are some ones like smart mobile phone with relatively big dispersion in ASL. Estimating ASL of products like display and solar-cell etc., the new approach is needed. In this paper a new method applied traditional Iowa curve with accelerated reliability test (indoor/outdoor) etc. is proposed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.3
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• pp.123-130
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• 2010

The aim of this paper is a seismic performance evaluation of metallic damper devices which are efficient in workability and installation process. For this V shape and S shape dampers is considered. The strut figures of dampers are V shape and S shape and, the research parameters are strut height and angle of the dampers. ABAQUS program is used for nonlinear finite element analysis. The analysis is performed with the hysteretic curve that has maximum displacement with 50mm and has increased progressive. As a results of evaluating the yield strength, maximum strength and energy dissipation capacity of each device, V and S shape have a good strength capacity and the devices with strut angle $60^{\circ}$ and strut height 140 and 200mm are evaluated stable in seismic behaviors. The response of S shape is more efficient than that of V shape. In the yield strength estimation process, proposed formula can not estimate the yield strength of V and S shape dampers. Even though, the formula can not consider the variation of strut heights and strut angles. Finally the S shape damper is recommended in seismic performance than V shape damper.