• Journal of Forest and Environmental Science
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• v.20 no.1
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• pp.93-109
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• 2004

To provide the basic informations related to forest road construction of mountainous terrain, we analyzed changes of the road structure factors such as banking and cutting slope gradients, slope length, road width by the environmental factors such as locations, slope gradients, soil types, road position on physically stabilized forest roads constructed in Gangwon-do. All factors related to the road structures by locations were significant except for banking slope length. Road width, longitudinal gradients, banking and cutting slope length by slope gradients were not significantly different and banking slope gradients in the range less than $30^{\circ}$, from $30^{\circ}$ to $35^{\circ}$ and more than $40^{\circ}$ and cutting slope gradients were significantly different for all areas. Road width, longitudinal gradients, banking slope length by soil types were not significantly different and others were significantly different. All factors related to the road structures by road position were significant except for cutting slope gradients.

• Journal of The Korean Astronomical Society
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• v.38 no.2
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• pp.149-151
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• 2005

We have studied the environmental effect on optical-NIR color gradients of 273 nearby elliptical galaxies. Color gradient is a good tool to study the evolutionary history of elliptical galaxies, since the steepness of the color gradient reflects merging history of early types. When an elliptical galaxy goes through many merging events, the color gradient can be get less steep or reversed due to mixing of stars. One simple way to measure color gradient is to compare half-light radii in different bands. We have compared the optical and near infrared half-light radii of 273 early-type galaxies from Pahre (1999). Not surprisingly, we find that $r_e(V)s$ (half-light radii measured in V-band) are in general larger than $r_e(K)s$ (half-light radii measured in K-band). However, when divided into different environments, we find that elliptical galaxies in the denser environment have gentler color gradients than those in the less dense environment. Our finding suggests that elliptical galaxies in the dense environment have undergone many merging events and the mixing of stars through the merging have created the gentle color gradients.

• Journal of Astronomy and Space Sciences
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• v.16 no.1
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• pp.1-10
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• 1999

The archival long-slit spectra, covering the wavelength range 4050 ~ 5150 $\AA$, have been used to investigate the radial behavior of absorption line fea-tures (G4300, Fe4383, Ca4455, Fe4531, and $H{\beta}$) of an elliptical galaxy NGC 5846A. The heliocentric recession velocity of NGC 5846 has been derived as $1949{\pm}87\;kms^{-1}$. Fe absorption lines of NGC 5846A show significant radial gradients with the mean slope of $\Delta/Delta(r")=-0.863\pm0.202$. There is also a significant radial gradient of G band with a slope of $-1.109{\pm}0.098$. On the other hand, no radial gradients has been detected on the Ca4455 and $H{\beta}$ absorptions of NGC 5846A. A metallicity gradient, which is derived from the Fe line gradients, is similar to the abundance gradient predicted by Larson's (1975) dissipative models for the formation of elliptical galaxies. We also note that a galaxy-galaxy interaction could affect the line gradients of NGC 5864A.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.53.2-53.2
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• 2014

Radial color gradient of early type galaxies (ETGs) is a key tool for studying the evolution of these galaxies. In this work, we investigated whether ETGs having negative or positive color gradients show any distinguishable characteristics in the galaxy properties. We selected sample of 211 ETGs at 0.01 < z < 0.5 in the Spitzer FLS field, then we constructed u-R color gradients. We obtained the stellar mass, specific star formation rate and fluxes of emission lines of each ETG from MPA-JHU DR7 catalog. Spitzer IRAC and MIPS 24 micron data were used to detect dust emission from the ETGs. Preliminary result shows that less massive galaxies are likely to have positive color gradients, which is probably due to the ongoing star formation in the galaxy core. Almost all AGNs have negative color gradients. This probably is because AGNs are located in relatively massive galaxies with little ongoing star formation. There exists a marginal difference in the percentage of galaxies with PAH emission between ETGs having positive color gradient and negative color gradient. This also supports that ETGs with positive color gradient are galaxies having enhanced star formation.

• Journal of the Korean Geosynthetics Society
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• v.8 no.4
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• pp.47-51
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• 2009

The slope failure in the country is caused by mainly rainfall and its type is reported shallow slope failures in general. To investigate the cause of slope failure, the unsaturated soil slope behavior in accordance with rainfall amount studies actively, but there are little studies related the slope erosion and scour by rainfall. The slope erosion and scour by rainfall cause environmental pollution and slope instability, however there are few methods to effectively control them. This research analyzed experimentally how infinite gradients are infiltrated according to the changes of amount of rainfall and the slope of gradients by manufacturing the model of gradient in order to investigate how rainfall infiltrates regarding homogeneous gradients and slope protection method. For this, this experiment measured and analyzed discharge, storage rate occurring in gradients by going on changing amount of rainfall, slope of gradients.

• Structural Engineering and Mechanics
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• v.83 no.5
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• pp.645-654
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• 2022

Environmental thermal loads such as vertical and lateral temperature gradients are significant factors that must be taken into account when designing the bridge. Different models have been developed and used by countries for simulating thermal gradients in bridge codes. In most of the codes only vertical temperature gradients are considered, such as Iranian Standard Loads for Bridge code (ISLB), which only considers the vertical gradient for bridge design proposes. On the other hand, the vertical gradient profile specified in ISLB, has many lacks due to the diversity of climate in Iran, and only one vertical gradient profile is defined for whole Iran. This paper aims to get the both vertical and lateral gradient loads for the concrete box girder using experimental analysis in the capital of Iran, Tehran. To fulfill this aim, thermocouples are installed in experimental concrete segment and temperatures in different location of the segment are recorded. A three dimensional finite element model of concrete box-girder bridge is constructed to study the effects of thermal loads. Results of investigation proved that the effects of thermal loads are not negligible, and must be considered in design processes. Moreover, a solution for reducing the negative effects of thermal gradients in bridges is proposed. Results of the simulation show that using one layer polyurethane insulation can significantly reduce the thermal gradients and thermal stresses.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.6
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• pp.78-84
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• 1996

In order to eliminate TPM(Total Particulate Matter) from a diesel engine, we designed and developed a particulate trap system using a burner, which was named as AEFR(Active Exhaust Feeding Regeneration) system. We have considered the temperature distributions and gradients in the filter being regenerated according to regeneration control schemes Ⅰ, Ⅱ and Ⅲ. Schemes Ⅲ has shown the most desirable peak temperature and temperature gradients in AFER system. Finally, it was concluded that much lower peak temperature and temperature gradients in the filter could be obtained than that of other advanced research results by our AEFR system.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.11 no.4
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• pp.293-298
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• 2011

In this paper, we propose a new image descriptor, that is, a rotation invariant histogram of oriented gradients (RIHOG). RIHOG overcomes a disadvantage of the histogram of oriented gradients (HOG), which is very sensitive to image rotation. The HOG only uses magnitude values of a pixel without considering neighboring pixels. The RIHOG uses the accumulated relative magnitude values of corresponding relative orientation calculated with neighboring pixels, which has an effect on reducing the sensitivity to image rotation. The performance of RIHOG is verified via the index of classification and classification of Brodatz texture data.

• Journal of Multimedia Information System
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• v.2 no.1
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• pp.171-178
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• 2015

This article describes 3 dimensional (3D) face recognition system using histogram of oriented gradients (HOG) based on face curvature. The surface curvatures in the face contain the most important personal feature information. In this paper, 3D face images are recognized by the face components: cheek, eyes, mouth, and nose. For the proposed approach, the first step uses the face curvatures which present the facial features for 3D face images, after normalization using the singular value decomposition (SVD). Fisherface method is then applied to each component curvature face. The reason for adapting the Fisherface method maintains the surface attribute for the face curvature, even though it can generate reduced image dimension. And histogram of oriented gradients (HOG) descriptor is one of the state-of-art methods which have been shown to significantly outperform the existing feature set for several objects detection and recognition. In the last step, the linear discriminant analysis is explained for each component. The experimental results showed that the proposed approach leads to higher detection accuracy rate than other methods.

• Korean Journal of Veterinary Research
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• v.29 no.1
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• pp.57-60
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• 1989

This study was carried out to evaluate the possibility of sex preselection by gradients methods using bovine serum albumin in rabbits. Artificial insemination was performed with sperm from the top and bottom layer of rabbit semen separated by bovine serum albumin gradients. Various characteristics of separated sperm, and the conception rate and secondary sex ratio at artificial insemination with separated sperm were compared. The results obtained were as follows. 1. The sperm from the bottom layer showed significanty high value in motility, percent of normal sperm and progressive motility as compared with control sperm and the sperm and the sperm from the top layer. 2. The conception rate of sperm from the bottom layer was higher than that of the top layer. But secondary sex ratio was not altered by this methods.