• Earthquakes and Structures
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• v.19 no.4
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• pp.287-301
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• 2020

Fragility as one of the most effective methods to evaluate seismic performance, which is greatly affected by damage index. Taking a multi span continuous rigid frame offshore bridge as an example. Based on fragility and reliability theory, considering coupling effect of time-varying durability damage of materials and time-varying attenuation effect of damage index to analyze seismic performance of offshore bridges. Results show that IDA curve considering time-varying damage index is obviously below that without considering; area enclosed by IDA of 1# pier and X-axis under No.1 earthquake considering this effect is 96% of that without considering. Area enclosed by damage index of 1# pier and X-axis under serious damage with considering time-varying damage index is 90% of that without considering in service period. Time-varying damage index has a greater impact on short pier when ground motion intensity is small, while it has a great impact on high pier when the intensity is large. The area enclosed by fragility of bridge system and X-axis under complete destruction considering time-varying damage index is 165% of that without considering when reach designed service life. Therefore, time-varying attenuation effect of damage index has a great impact on seismic performance of bridge in service period.

• International Journal of Highway Engineering
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• v.18 no.4
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• pp.77-82
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• 2016

PURPOSES : This paper proposes a reliability index for the safety evaluation of freeway sections. It establishes a reliability index as a safety surrogate on freeways considering speeds and speed dispersions. METHODS : We collated values of design elements including radii, curve lengths, vertical slopes (absolute values), superelevations, and vertical slopes from seven freeway sections in Korea. We also collected data about driving speeds, traffic accidents, and their deviations. We established a reliability index using these variables. RESULTS : The average radii, curve lengths, and superelevations are highly correlated with the incidence of traffic accidents. Deviations in radius and curve lengths show an especially high correlation. The reliability index, derived from speed and speed dispersions of the seven freeway sections, also correlated highly with accidents with a correlation index of 0.63. CONCLUSIONS : Since the reliability index obtained from speed and speed dispersions are highly correlated with traffic accidents, we conclude that a reliability index can be a safety surrogate on freeways considering speeds and speed dispersions together in terms of design and operational levels.

• Journal of Biomedical Engineering Research
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• v.29 no.5
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• pp.400-407
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• 2008

A health index was proposed that evaluates personal health state from both measured physiological variables and survey questions. Four health indices were defined such as cardiovascular index, stress index, obesity index, and management index. The total health index was calculated by summing these four health indices. Physiological variables such as blood pressure, heart rate variability(HRV), accelerated photoplethysmograph(APG), and body fat percentage were non-invasively measured and a survey questionnaire that asks personal health state, exercise intensity, and food preference was developed. The suggested health index was applied to thirty eight persons including 30 patients and 8 normal persons with an average age of 51.8. The average health index was estimated to be 75.1 out of 100 points. Young age group(below 50) and men group showed higher health indices than the aged(over 50) and women groups. The correlation coefficient between the cardiovascular index and stress index was found to be 0.513, which means stress is related to cardiovascular health state. The correlation coefficient between the measurements and survey questions was 0.385 for the cardiovascular index. It was as low as 0.182 for the stress index. More case studies may improve correlations between measurements and survey questions, and then, the current health index system may develop as an effective tool to evaluate personal health state.

• Korean Journal of Environment and Ecology
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• v.25 no.3
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• pp.389-403
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• 2011

Studies on effects of human action on the destruction of ecosystems and changes in biodiversity are being processed actively from the view point of landscape ecology. This study investigated present distribution status of the naturalization plant by disturbance of natural ecosystem which could be seen on 35 rural villages in Korea. The study made a landuse map on the study area then quantified the landscape ecologic characteristic using landscape index based on this landuse map. Correlation between landscape index on the study area and distribution characteristic of naturalization plant was analyzed. The landscape index was calculated by FRAGSTATS, a spatial analysis program, and naturalization index and urbanization index were used in the distribution characteristic of naturalization plant. As a result, naturalization index and patch density, naturalization index and edge density, naturalization index and area-weighted mean shape index were shown as having positive correlation, and naturalization and core area percentage of landscape, naturalization index and mean core area were displayed as having negative correlation.

• Journal of the Korean Society of Clothing and Textiles
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• v.38 no.4
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• pp.584-597
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• 2014

This study verified the 'Hemline Index' theory by George (1926) and established a new fashion theory frame to forecast future fashion cycles of skirts by analyzing the past fashion cycle of skirts through a diachronic method. Skirt pictures from 1980-2013 (the post-industrialized period of Korea) were analyzed and representative skirt styles, the fashion cycle of skirts and relation between skirt style, length, width and stock index were identified. A total of 1496 pictures in fashion magazine published over 34 years were selected and analyzed using PASW 18.0. The results were: For 34 years, representative skirts styles were mini skirt, midi skirt and long skirt. Fashion trend cycles of skirt length decreased for 10 years and the fashion cycle showed a trend to shorten. Skirt length & stock index related negatively and skirt length & skirt width related positively. All relations revealed significant results. Finally, the 'Hemline Index' theory of George (1926) was verified. Fashion marketers can develop successful and suitable products using a fashion cycle theory based on the results of this study.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.1
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• pp.12-23
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• 2001

Extended path expressions are used to denote multiple paths concisely by using '$\ast$' character. They are convenient for expressing OQL queries to retrieve XML data stored in OODBs. In this paper, we propose a multi-path index scheme as a new index scheme to efficiently process queries with extended path expressions. Our proposed index scheme allocates a unique path identifier for every possible single path in an extended path expression and provides functionalities of both a single path indexing and multiple path indexing through the composition of index key and path identifier while using only a index structure. The proposed index scheme provides better performance than single-path index schemes, and is practical since it can be implemented by little modification of leaf records of a B+-tree index.

• Journal of the Korean Society for Precision Engineering
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• v.8 no.3
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• pp.18-26
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• 1991

A study on the measuring and evaluation of LSC(Least Square Center) roundness was carried out. The experimental set-up was made by index head and indicator, and the measuring data were compensated by a developed computer program. The results obtained are as follows : 1) An index head can conveniently be used to measure LSC roundness. 2) A program for calculating LSC roundness is developed. 3) Without a high quality roundnes measuring apparatus, LSC roundness can be measured and calculated by using index head and the developed program in machine shop as well as in a measuring room

• Journal of Korea Foundry Society
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• v.38 no.5
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• pp.95-102
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• 2018

The dependence of the tensile properties on variations in the porosity of A356 aluminium alloys was investigated in terms of the quality index of the tensile properties based upon the ultimate tensile strength and elongation as well as the variation of the strength coefficient and strain-hardening exponent with regard to a T6 treatment. The test specimens were prepared by low-pressure die-casting and a subsequent T6 treatment, and the experimental results of a tensile test carried out at room temperature were compared to the theoretical description using a modified constitutive model. The nominal value of the quality index of A356 alloys increases gradually with a lapse of the ageing time upon a T6 treatment, despite the fact that this value is temporarily decreased during the initial stage of ageing from a solutionised condition. Additionally, the quality index depends practically upon the porosity variation with a power law relationship without regard to whether in solutionised or artificial aged conditions. The theoretical description indicates that the strength coefficient directly determines the nominal level of the quality index. Moreover, the overall dependence of the quality index on the porosity variation is remarkably weakened with an increase in the tensile strain, whereas the quality index depends sensitively upon the porosity variation with a low value of the strain-hardening exponent.

• International Journal of Automotive Technology
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• v.7 no.7
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• pp.821-826
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• 2006

This paper describes a rollover index (RI)-based rollover mitigation control (RMC) system. A rollover index which indicates an impending rollover has been developed by a roll dynamics phase plane analysis. The rollover index is calculated using the roll angle, the roll rate, the lateral acceleration and time to wheel lift (TTWL). A differential braking control law based on a 2-D bicycle model has been designed using the direct yaw control (DYC) method. An RMC threshold has been determined from the rollover index. The performance of the RMC scheme and the effectiveness of the proposed rollover index are illustrated using a vehicle simulator.

• Communications for Statistical Applications and Methods
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• v.26 no.1
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• pp.69-78
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• 2019

A structured model with both single-index and varying coefficients is a powerful tool in modeling high dimensional data. It has been widely used because the single-index can overcome the curse of dimensionality and varying coefficients can allow nonlinear interaction effects in the model. For high dimensional index vectors, variable selection becomes an important question in the model building process. In this paper, we propose an efficient estimation and a variable selection method based on a smoothing spline approach in a partially linear single-index-coefficient regression model. We also propose an efficient algorithm for simultaneously estimating the coefficient functions in a data-adaptive lower-dimensional approximation space and selecting significant variables in the index with the adaptive LASSO penalty. The empirical performance of the proposed method is illustrated with simulated and real data examples.