• Korean Journal of Construction Engineering and Management
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• 제7권2호
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• pp.171-180
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• 2006

Change is inevitable and is a reality of construction projects. Most construction contracts include change clauses and allowing contractors an equitable adjustment to the contract price and duration caused by change. However, the actions of a contractor can cause a loss of productivity and furthermore can result in disruption of the whole project because of a cumulative or ripple effect. Because of its complicated nature, it becomes a complex issue to determine the cumulative impact (ripple effect) caused by single or multiple change orders. Furthermore, owners and contractors do not always agree on the adjusted contract price for the cumulative impact of the changes. A number of studies have attempted to quantify the impact of change orders on project costs and schedule. Many of these attempted to develop regression models to quantify the loss. However, regression analysis has shortcomings in dealing with many qualitative or noisy input data. This study develops ANN models to classify and quantify the labor productivity losses that are caused by the cumulative impact of change orders. The results show that ANN models give significantly improved performance compared to traditional statistical models.

• Asian Pacific Journal of Cancer Prevention
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• 제14권5호
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• pp.3219-3221
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• 2013

Background: This study used receiver operating characteristic (ROC) curves to screen Surveillance, Epidemiology and End Results (SEER) skin melanoma data to identify and quantify the effects of socioeconomic factors on cause specific survival. Methods: 'SEER cause-specific death classification' used as the outcome variable. The area under the ROC curve was to select best pretreatment predictors for further multivariate analysis with socioeconomic factors. Race and other socioeconomic factors including rural-urban residence, county level % college graduate and county level family income were used as predictors. Univariate and multivariate analyses were performed to identify and quantify the independent socioeconomic predictors. Results: This study included 49,999 parients. The mean follow up time (SD) was 59.4 (17.1) months. SEER staging (ROC area of 0.08) was the most predictive foctor. Race, lower county family income, rural residence, and lower county education attainment were significant univariates, but rural residence was not significant under multivariate analysis. Living in poor neighborhoods was associated with a 2-4% disadvantage in actuarial cause specific survival. Conclusions: Racial and socioeconomic factors have a significant impact on the survival of melanoma patients. This generates the hypothesis that ensuring access to cancer care may eliminate these outcome disparities.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• 제22권1호
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• pp.50-55
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• 2013

In order to understand the biomaterial like the blood vessel of artery, there is a need to quantify the biomechanical behavior of the vessel. However, theoretical framework to describe and quantify the behaviour of blood vessel was not well established so far. For studying the biomechanical behavior of artery, Rubber-liked material which is similar to passive artery is selected since conventional theoretical interpretation is very limited to understand and predict the behavior of biomaterial. Rubber-like material is assumed to be very similar to artery and has properties of isotropy, homogeneity and is undergoing large deformation. Based on this assumption, stress developed on Rubber-like material is described by strain energy function and strain invariants which are required to understand the nonlinear elastic behavior of biomaterial. The descriptor which would be used for understanding the biomechanical behavior of artery is studied in this work.

• Proceedings of the Korean Geotechical Society Conference
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.1182-1189
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• 2010

The mechanical behavior of a granular material is governed by the applying effective stresses and its skeletal structure which is considered to be the packing of particles giving overall density and degree of anisotropic. Factors that affect soil packing are the particle size, size distribution and shape, and the arrangement of grain contact. Soil particle size and shape are the most important factor, but difficult to quantify. In this study, 2D Fourier analysis is applied to quantify the shape of granular particles. Jumunjin sand was used in the experiment and particle images are captured using an optical microscope. The results showed that three lower order Fourier descriptor are closely related with roundness, sphericity of the granular particle. Also statistical approach is used to determine roundness, form factor, elongation ratio, roughness of Jumunjin sand.

• Proceedings of the KSME Conference
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.792-795
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• 2007

To quantify irregular body motions the time series analysis was applied to the gait study. The motions obtained from gait experiment are complex to exhibit nonlinear behaviors. The purpose of this study is to measure quantitatively the characteristics of the major six joints of the body during walking. The gait experiments were carried out for eighteen young males walking on a motor driven treadmill. Joint motions were captured using eight video cameras, and then three dimensional kinematics of the neck and the upper and lower extremities were computed by KWON 3D motion analysis software. The largest Lyapunov exponent was calculated from the time series to quantify stabilities of each joint. The results provides a data set of nonlinear dynamic characteristics for six joints engaged in normal walking.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• 제31권3호
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• pp.54-59
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• 1999

This study was to quantify fiber distributions in thickness direction of kenaf handsheets as a fiber distribution index (FDI) and to analyze the relationship between FDI and the handsheet properties. The images of fiber distribution in z-direction were obtained by Confocal Laser Scanning Microscope (CLSM) and analyzed by image analysis technique. The proposed FDI had a good correlation with high R2 vlaues with various properties of paper, such as apparent density, scattering coefficient , burst index, tear index, tensile index, and folding endurance. The proposed FDI was shown as a good index to quantify paper properties.

• International Journal of Aeronautical and Space Sciences
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• 제7권2호
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• pp.86-103
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• 2006

Using a combination of force transducer measurement to quantify net lift force, high frame rate camera to quantify and subtract inertial contributions, and Digital Particle Image Velocimetry (DPIV) to calculate aerodynamic contributions in the spanwise plane, the contribution of spanwise flow to the generation of lift force in wings undergoing a pure flapping motion in hover is shown as a function of flapping angle throughout the flapping cycle. These experiments were repeated at various flapping frequencies and for various wing planform sizes for flat plate and span wise cambered wings. Despite the previous identification of the importance of span wise fluid structures in the generation of lift force in flapping wings throughout the existing body of literature, the direct contribution of spanwise flow to lift force generated has not previously been quantified. Therefore, in the same manner as commonly applied to investigate the chordwise lift distribution across an airfoil in flapping wings, spanwise flow due to bulk flow and rotational fluid dynamic mechanisms will be investigated to validate the existence of a direct component of the lift force originating from the flapping motion in the spanwise plane instead.

• Nuclear Engineering and Technology
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• 제46권3호
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• pp.281-290
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• 2014

In order to properly quantify fission reactor neutronics parameter uncertainties, we have to use covariance data and sensitivity profiles consistently. In the present paper, we establish two consistent methodologies for uncertainty quantification: a self-shielded cross section-based consistent methodology and an infinitely-diluted cross section-based consistent methodology. With these methodologies and the covariance data of uranium-238 nuclear data given in JENDL-3.3, we quantify uncertainties of infinite neutron multiplication factors of light water reactor and fast reactor fuel cells. While an inconsistent methodology gives results which depend on the energy group structure of neutron flux and neutron-nuclide reaction cross section representation, both the consistent methodologies give fair results with no such dependences.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
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• pp.168-171
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• 2001

Organobentonite modified with hexadecyltrimethylammonium (HDTMA) was used to quantify an adsorption of heavy metals. Based on preliminary experiments, optimal soil/solution ratio, a range of pH, and electrolyte were selected. Adsorption experiments of cadmium and lead were conducted to quantify an adsorption selectivity to bentonite and organobentonite. Adsorption of cadmium and lead to bentonite was increased with increasing a soil/solution ratio. Adsorption of cadmium and lead to bentonite was increased with increasing a soil/solution ratio. Adsorptions of heavy metal to organobentonite were slightly reduced relative to bentonite. This study used the principle of hard-soft-acid-base (HBAB) to interpretate an adsorption mechanism. Because of competition between cadmium and lead. adsorption of cadmium and lead was reduced in mixture of heavy metals. Adsorption selectivity.

• Journal of Advanced Marine Engineering and Technology
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• 제29권6호
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• pp.645-653
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• 2005

The effects of a WI(Water Injection) at the intake Pipe and an urea injection at the exhaust pipe for a 4-cylinder DI(Direct Injection) diesel engine were investigated experimentally The water quantity was controlled by temperature of intake manifold and MAF(Manifold Air Flow). In addition, the urea quantify was controlled by NOx quantify and MAF. Effects of WI system, urea-SCR system and tandem system were investigated for with and without EGR(Exhaust Gas Recirculation). As the results. the SUF(Stoichiometric Urea Flow) and NOx map were obtained. In addition, NOx results can be visualized with engine speed and engine load. It was concluded. therefore, that the NOx reduction effects of the tandem system without the EGR were more than those with the EGR base engine.