• Korean Journal of Agricultural Science
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• v.23 no.1
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• pp.25-38
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• 1996

To investigate the stability problem of irrigation-drainage channel excavation slope on soft ground, analyzed the behavior of the soft ground with excavation slope by the limit equilibrium method and the finite element method, and compared with field tests. The results of this study were summarized as follows; 1. When rapid drawdown the water level, the crack was occurred by the effect of the excess pore water pressure, and the pore water pressure was decreased slowly. 2. As the width of excavation was larger, the crack width was larger. And, excavated depth was deeper, the progressive failure was appeared. 3. When the soft ground excavation was small-scale, the minimum safety factor was more effected by cohesion(1.0, 1.5, 2.0, 2.5, 3.0) than excavated slope inclination(1:l, 1:1.5, 1:2). 4. As excavation was progressed, the settlement occurred on the top-slope due to plastic domain, and heaving was occurred at the bottom of excavation. 5. The maximum shear stress was appeared greatly as the base part of slope went down. Because of the increase of the maximum shear stress, tension area occurred and local failure possibility was increased. 6. As the excavation depth was increased, the maximum shear strain was appeared greatly at the base of slope and distribution pattern was concentrated beneath the middle of slope.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.2
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• pp.201-211
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• 2005

Due to the complex mechanism and various parameters that affect shear behavior of reinforced concrete (RC) members, models on shear tend to be complex and difficult to utilize for design of structural members, and empirical relationships formulated with limited test data often work lot members having a specific range of influencing parameters on shear. As an alternative approach tot solving this problem, artificial neural networks have been suggested by some researchers. In this paper, artificial neural networks were used to predict shear strengths of RC beams without shear reinforcement. Especially, a large database that consists of shear test results of 398 RC members without shear reinforcement was used for artificial neural network analysis. Three well known approaches for shear strength of RC members, ACI 318-02 shear provision, Zsutiy's equation, and Okamura's relationship, are also evaluated with test results in the shear database and compared with neural network approach. While ACI 318-02 provided inaccurate predictions for RC members without shear reinforcement, the empirical equations by Zsutty and Okamura provided more improved prediction of Shear strength than ACI 318-02. The artificial neural networks, however provided the best prediction of shear strengths of RC beams without shear reinforcement that was closest to test results.

• Management & Information Systems Review
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• v.31 no.2
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• pp.199-230
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• 2012

This study introduced trust dimension as a mediating variable and analyzed in order to investigate the empirical mechanism on the process of leader's emotional intelligence which is a emotional factor to produce organizational effectiveness. Based on the empirical analysis, first of all, this study found whether the team leader's emotional intelligence gives an influence on the subordinate's trust in leader. Secondly, this study examined the multidimensionality of trust by selecting subordinate's cognition-based trust and affect-based trust on the team leader as mediating variables between team leaders's emotional intelligence and subordinate's affective commitment, organizational citizenship behavior. I found the theoretical implications based on this study; first, from the view on cognition-based and emotion-based trust, the integrated verification of the process of the trust in leader as a mediating role, second, verification of the relationship between leader's emotional intelligence and trust in leader which was not studied before, third, the methodological try to prevent from the common method bias problem through the evaluation of a team leader on a subordinate's organizational citizenship behavior. This study also suggested the ways to apply those theoretical implications to human resource management.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.1
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• pp.99-107
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• 2001

Manufacture of fishing vessel is needed the effective material for light, strength, fire and corrosion of water in order to improve durability by high-speed and fishing. These fishing vessel can be divided into FRP and AI alloys fishing vessel. FRP fishing vessel is light and effective for strength but highly ignited and susceptible to heat during the manufacturing ship by-produce noxious component for human. In the case of a scrapped ship, it cause environmental pollution. On the other hand, aluminum is a material in return for FRP and has merit of high-strength and lightness. It's more heat proof and durable than FRP and superior to prevent from corrosion. Al alloys fishing vessel development is rising as an urgent matter. But, al alloy has some defect of bad weldability, welding transformation, cracks and overcost of construction. Therefore this study is to develop the new welding joint shape solving aluminum defects and mechanical behavior. First of all, strength was compared and reviewed by analysis of plate, stiffen plate, new model simplified by using plate theory. On the base of this result, plate and new model of temperature distribution, weld residual stress and strength of tensile, compressive force were compared and reviewed by finite element computer program has been developed to deal with heat conduction and thermal elasto plastic problem. Also, new model is proved application possibility and excellent mechanic by strength comparison is established to tensile testing result.

• Geophysics and Geophysical Exploration
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• v.11 no.1
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• pp.68-77
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• 2008

We have developed an inversion algorithm for loop-loop electromagnetic (EM) data, based on the localised non-linear or extended Born approximation to the solution of the 2.5D integral equation describing an EM scattering problem. Source and receiver configuration may be horizontal co-planar (HCP) or vertical co-planar (VCP). Both multi-frequency and multi-separation data can be incorporated. Our inversion code runs on a PC platform without heavy computational load. For the sake of stable and high-resolution performance of the inversion, we implemented an algorithm determining an optimum spatially varying Lagrangian multiplier as a function of sensitivity distribution, through parameter resolution matrix and Backus-Gilbert spread function analysis. Considering that the different source-receiver orientation characteristics cause inconsistent sensitivities to the resistivity structure in simultaneous inversion of HCP and VCP data, which affects the stability and resolution of the inversion result, we adapted a weighting scheme based on the variances of misfits between the measured and calculated datasets. The accuracy of the modelling code that we have developed has been proven over the frequency, conductivity, and geometric ranges typically used in a loop-loop EM system through comparison with 2.5D finite-element modelling results. We first applied the inversion to synthetic data, from a model with resistive as well as conductive inhomogeneities embedded in a homogeneous half-space, to validate its performance. Applying the inversion to field data and comparing the result with that of dc resistivity data, we conclude that the newly developed algorithm provides a reasonable image of the subsurface.

• Korean Journal of Optics and Photonics
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• v.20 no.2
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• pp.94-101
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• 2009

A novel method for the reconstruction of 3D shape and texture from elemental images has been proposed. Using this method, we can estimate a full 3D polygonal model of objects with seamless triangulation. But in the triangulation process, all the objects are stitched. This generates phantom surfaces that bridge depth discontinuities between different objects. To solve this problem we need to connect points only within a single object. We adopt a segmentation process to this end. The entire process of the proposed method is as follows. First, the central pixel of each elemental image is computed to extract spatial position of objects by correspondence analysis. Second, the object points of central pixels from neighboring elemental images are projected onto a specific elemental image. Then, the center sub-image is segmented and each object is labeled. We used the normalized cut algorithm for segmentation of the center sub-image. To enhance the speed of segmentation we applied the watershed algorithm before the normalized cut. Using the segmentation results, the subdivision process is applied to pixels only within the same objects. The refined grid is filtered with median and Gaussian filters to improve reconstruction quality. Finally, each vertex is connected and an object-based triangular mesh is formed. We conducted experiments using real objects and verified our proposed method.

• Korean Journal of Environmental Agriculture
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• v.28 no.1
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• pp.32-37
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• 2009

This study was conducted to assess the impact of agricultural land use on the water quality in mountain village farmlands. Two soil types, paddy and upland soil were analysed for their chemical properties. Although, pH and organic matter contents were not significantly different to each other, concentrations of available P and exchangeable K and Ca were much higher in upland soil compared with those in paddy soil. The results of water quality analysis indicated that, in Goseong-cheon watershed, the nutrients contents were much higher in downstream area than in upstream area. Particularly, the elevation of $COD_{Mn}$ and T-P were significant during rainy season. When paddy fields coexist with upland fields, SS, T-N, and T-P concentrations in paddy fields were lower than those of upland fields. This may indicate that paddy fields possess an water-purifying ability by absorbing nutrients. This effect may reduce excessive nutrients discharged into the neighboring streams which may cause eutrophication problem. The difference between inflow and outflow of nitrogen and phosphorus during the cultivation period were measured as -98.9 kg $ha^{-1}$ and -29.7 kg $ha^{-1}$, which means that nutrient outflow was higher than inflow. This may suggest that much nutrient was discharged during the crop harvest period.

• Journal of Environmental Impact Assessment
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• v.22 no.6
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• pp.547-556
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• 2013

Recently, golf courses have increased over the years because golf became popular leisure sport. Various environmental problems have been then issued by a golf course during constructing and running them. A problem of pesticide, which is serious among various environmental problems, from golf course has harmful effect on surrounding area and makes human suffer from acute and chronic diseases. Pesticides are used for the cost-effective managing of golf course and the amount of pesticides also increases as the number of golf course increase. Since the assessment of pesticides on near-by surrounding has been focused on water and soil media, studies related to atmospheric dispersion have been hardly attempted. The method to assess an impact of pesticide nearby agricultural production by the atmospheric dispersion using AGDISP(AGricultural DISPersal) model was developed and applied to the actual planned golf course located in Hongcheon, Gangwon. For implementing AGDISP, parameters were investigated from the golf course's land use planning map, pesticide spray device, Hong-Cheon weather station and etc. First of all, a kind of pesticide, a form of spraying pesticide, geographical features, weather data, and distance(golf course to plantation) were investigated to understand how to work these parameters in AGDISP. Restricted data(slope angle, droplet size distribution and solar insolation) sensitivity analysis of these parameters to estimate effect of pesticide nearby a plantation and a high relative contribution data of analyzed data was selected for input data. Ethoprophos was chosen as the pesticide used in the golf course and the amounts of pesticide deposition per annual agricultural productions were predicted. The results show that maximum amount of pesticide deposition through atmospheric dispersion was predicted $2.32{\mu}/m^2$ at 96 m where the nearest organic plantation exists. The residues of pesticide were also estimated based on the annul production of the organic and the deposition amount of the pesticide. Consequently, buckwheat, wheat and millet were likely to exceed maximum residue limits for pesticides in foods(MRL) and sorghum, corn and peanut were likely to exceed MRL by organic farming as well.

• Journal of radiological science and technology
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• v.33 no.3
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• pp.203-211
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• 2010

The purpose of this study is meant to develop an evaluation framework for PBL and S-PBL package, as well as verify reliability and propriety of developed framework. To achieve the purpose, existing researches and related documents were considered, and composed basic questionnaire which fits to the basic frame of the framework, 3 categories 15 items for PBL/S-PBL. Verifying its contents propriety, examined by 9 experts who professors in college and made 14 items for PBL, 15 items for S-PBL. To verify construct validity of basic frameworks, carried out factor analysis. Final evaluation framework questionnaire were 15 items selected, its PBL for 3 items in motivating, 7 items in integrity, 4 items in systematic and total 14 items, S-PBL for 4 items in motivating, 6 items in integrity, 5 items in systematic and total 15 items, and was verify to have adequate reliability with Cronbach's $\alpha$ is 0.9112 in PBL, 0.9166 of S-PBL.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.99-106
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• 2004

This paper presents some comparisons between Cournot-Nash and Stackelberg game in bi-level program, composed of both upper level program and lower level one. The upper level can be formulated to optimize a specific objective function, while the lower formulated to express travelers' behavior patterns corresponding to the design parameter of upper level problem. This kind of hi-level program is to determine a design parameter, which leads the road network to an optimal state. Bi-level program includes traffic signal control, traffic information provision, congestion charge and new transportation mode introduction as well as road expansion. From the view point of game theory, many existing algorithms for bi-level program such as IOA (Iterative Optimization Assignment) or IEA (Iterative Estimation Assignment) belong to Cournot-Nash game. But sensitivity-based algorithms belongs to Stackelberg one because they consider the reaction of the lower level program. These two game models would be compared by using an example network and show some results that there is no superiority between the models in deterministic case, but in stochastic case Stackelberg approach is better than that of Cournot-Nash one as we expect.