• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.7 no.2
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• pp.5-22
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• 2001

The purpose of this study was to investigate the balancing training effect on weight bearing ratio and postural sway on the unstable surface for the CVA patients with balance disability. The inclusion criteria were walking independently 20m distances. Eighteen subjects, 4 with right and 14 with left hemiplegic patients were participated in this study. The range of age was from 35 to 75 and the duration from onset time was from 1 to 38 months. The intervention program including balancing training that they were introduced for 10 minutes every other day during 12 weeks to experimental group, and general therapeutic exercise to control group. The result of this study were as following; 1. The balancing training on the unstable surface showed that the postural sway of left/right distribution would appear more effective on sitting with eyes opened. 2. The balancing training on the unstable surface showed that the postural sway of forward/rear distribution, left/right distribution and distance would appear more effective on standing with eyes opened. 3. The balancing training on unstable surface would increase more effective on the weight-bearing ratio of left/right difference and frequency. 4. The balancing training on unstable surface was statistical significant on the postural sway of left/right distribution and area in experimental group. and it was statistical significant on the postural sway of forward/rear distribution, left/right distribution and distance in control group, too.

• Journal of Korea Water Resources Association
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• v.51 no.5
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• pp.417-424
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• 2018

This study analyzed the effect of irrigation reservoirs, antecedent soil moisture conditions (AMC) and Huff time distribution on peak discharge using Monte Carlo simulation. The peak discharge was estimated for four different cases in combination of irrigation reservoir capacity, AMC, and Huff time distribution. Applying 100% reservoir capacity or AMC-III, the peak discharges corresponding return periods of 50~300 years were overestimated by 25~30% compared to those of cases that considered the probability of occurrence for individual condition. Applying the 3rd quantile huff distribution, the peak discharges were overestimated by 5% over the peak discharge that considered the probability of occurrence. The overall results indicated that the effect on the peak flood of Huff distribution was less than AMC and reservoir storage.

• Computers and Concrete
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• v.16 no.3
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• pp.357-380
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• 2015

In this study, a simple indeterminate strut-tie model which reflects complicated characteristics of the ultimate structural behavior of continuous reinforced concrete deep beams was proposed. In addition, the load distribution ratio, defined as the fraction of applied load transferred by a vertical tie of truss load transfer mechanism, was proposed to help structural designers perform the analysis and design of continuous reinforced concrete deep beams by using the strut-tie model approaches of current design codes. In the determination of the load distribution ratio, a concept of balanced shear reinforcement ratio requiring a simultaneous failure of inclined concrete strut and vertical steel tie was introduced to ensure the ductile shear failure of reinforced concrete deep beams, and the primary design variables including the shear span-to-effective depth ratio, flexural reinforcement ratio, and compressive strength of concrete were reflected upon. To verify the appropriateness of the present study, the ultimate strength of 58 continuous reinforced concrete deep beams tested to shear failure was evaluated by the ACI 318M-11's strut-tie model approach associated with the presented indeterminate strut-tie model and load distribution ratio. The ultimate strength of the continuous deep beams was also estimated by the experimental shear equations, conventional design codes that were based on experimental and theoretical shear strength models, and current strut-tie model design codes. The validity of the proposed strut-tie model and load distribution ratio was examined through the comparison of the strength analysis results classified according to the primary design variables. The present study associated with the indeterminate strut-tie model and load distribution ratio evaluated the ultimate strength of the continuous deep beams fairly well compared with those by other approaches. In addition, the present approach reflected the effects of the primary design variables on the ultimate strength of the continuous deep beams consistently and reasonably. The present study may provide an opportunity to help structural designers conduct the rational and practical strut-tie model design of continuous deep beams.

• Structural Engineering and Mechanics
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• v.74 no.1
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• pp.55-67
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• 2020

The common practice to predict the characteristic structural load effects (LEs) in long reference periods is to employ the extreme value theory (EVT) for building limit distributions. However, most applications ignore that LEs are driven by multiple loading events and thus do not have the identical distribution, a prerequisite for EVT. In this study, we propose the composite extreme value modeling approach using clustering to (a) cluster initial blended samples into finite identical distributed subsamples using the finite mixture model, expectation-maximization algorithm, and the Akaike information criterion; (b) combine limit distributions of subsamples into a composite prediction equation using the generalized Pareto distribution based on a joint threshold. The proposed approach was validated both through numerical examples with known solutions and engineering applications of bridge traffic LEs on a long-span bridge. The results indicate that a joint threshold largely benefits the composite extreme value modeling, many appropriate tail approaching models can be used, and the equation form is simply the sum of the weighted models. In numerical examples, the proposed approach using clustering generated accurate extrema prediction of any reference period compared with the known solutions, whereas the common practice of employing EVT without clustering on the mixture data showed large deviations. Real-world bridge traffic LEs are driven by multi-events and present multipeak distributions, and the proposed approach is more capable of capturing the tendency of tailed LEs than the conventional approach. The proposed approach is expected to have wide applications to general problems such as samples that are driven by multiple events and that do not have the identical distribution.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.31 no.4
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• pp.41-48
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• 2008

The purpose of this study was to investigate the job stress factors that were related to the general characteristics, work characteristics, and health characteristics of the workers at distribution industry. The survey of job stress measurement scale for Korean employee which was developed by KOSHA and OSHRI in 2003 was used for this study. Three hundred and fifty workers at distribution industry participated in this study, and among them 326 responses were analyzed for this study due to the unreliability and insincerity of responses. Eight job stress factors like physical environment, self-control for the job, job unsecure, organization system, workplace culture, compensation for the job, relationship to the superior, and job requirement were analyzed. The results showed that the stress because of self control for the job was relatively higher than that of other industry workers. However, the stress because of physical environment, job requirement, job unsecure, organization system and compensation for the job was relatively lower than that of other industry workers. The female workers felt more stress than male workers in compensation for the job and workplace culture factors at distribution industry. The delivery and carrying job workers were more stressful than those of other jobs at distribution industry because of physical environments and self-control for the job. The non-regular job workers were more stressful than regular job workers in many stress factors like self-control for the job, job unsecure, organization system and compensation for the job.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.1
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• pp.10-19
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• 2006

Statement of problem : The various kinds of properties of post and core may affect the stress distribution to the root of endodontically treated teeth Purpose: To evaluate the influence of various kinds of properties of post and core to the stress distribution to the root of endodontically treated teeth. Material and methods: Mandibular first premolar, prepared by general shape of post and core with gold crown, was used to two dimensional axisymmetric modeling for finite element analysis. Then property values of 8 different kinds of post and core was substituted for each. Finally, stress distribution shown areas around the root of post and core was analysed after applying 50N of vortical and oblique load. Results: 1. Stress value of oblique load was much higher than the maximum stress value of vertical load. 2. Under oblique load, very concentrated stress was located on post periapical area and variations in stress were very severe. Contrary to this, stress distribution was relatively uniform in vertical load. 3. Post materials with higher elastic modulus showed relatively more apically focused stress, and post materials with lower elastic modulus showed stress focused on cervical area on the axial wall of post. 4. Stress change according to the properties of core was shown only in the cervical area of post and below core as the higher elastic modulus, then increased in stress. 5. Post and core with medium value of elastic modulus showed relatively uniform stress distribution. Conclusions: Post materials with higher elastic modulus showed relatively more apically focused stress, and post materials with lower elastic modulus showed stress focused on cervical area on the axial wall of post. Stress change according to the properties of core was shown only in the cervical area of post and below core.

• Korean Journal of Remote Sensing
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• v.22 no.1
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• pp.1-10
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• 2006

During the northern burning season, biomass burning is found north of the equator, while satellite estimates from the residual-type method such as the CCD method show higher ozone south of the equator. This discrepancy is called the tropical Atlantic paradox (Thompson et ai., 2000). We use satellite and ground-based measurements to investigate the paradox. When the background tropospheric ozone over the Pacific Ocean from TOMS measurements is subtracted from the latitudinal total ozone distribution (e.g. TOMS-Pacific method), the results show remarkable agreement with the latitudinal stratospheric ozone distribution using the CCD method. The latitudinal tropospheric ozone distribution using the CCD method, with a persistent maximum over the southern tropical Atlantic, is also seen in the latitudinal tropospheric ozone distribution using the TOMS-Pacific method. It suggests that the complicated CCD method can be replaced by the simple TOMS-Pacific method. However, the tropical Atlantic paradox exists in the results of both the CCD and TOMS-Pacific methods during the northern buming season. In order to investigate this paradox, we compare the latitudinal ozone distributions using the CCD and TOMS-Pacific methods by using the SAGE measurements (e.g. TOMS-SAGE method) and the SHADOZ ozonesoundings (e.g. TOMS-Sonde method) assuming zonally invariant stratospheric ozone, which is the same assumption as of the CCD method. During the northern burning season, the latitudinal distributions in the tropospheric ozone derived from the TOMS-SAGE and TOMS-Sonde methods show higher tropospheric ozone over the northern tropical Atlantic than the southern Atlantic due to a stronger gradient in stratospheric ozone relative to that from the CCD and TOMS-Pacific methods. This indicates that the latitudinal tropospheric ozone distribution can be changed depending on the data that is used to determine the latitudinal stratospheric ozone distribution. Therefore, there is a possibility that the north-south gradient in stratospheric ozone over the Atlantic can be a solution of the paradox.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.687-693
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• 2018

The active development of the global marine trade industries has been known to increase the inflows of marine invasive species and harmful organisms into the ecosystem, and the marine ecological disturbances. One of these invasive species, Ciona robusta, has now spread to the Korea Strait, the East Sea, and Jeju Island in connection with the climate change but not the Yellow Sea in Korea. Currently, the spread and distribution of C. robusta is increasingly damaging aquaculture and related facilities. Therefore, this study aims to identify the spread of C. robusta and potential habitats and to secure a data for the prevention of effective management measures due to climate change as well as damage the reduction in future through the prediction of spread. We used environmental variables in BioOracle. Also, the potential habitat and distribution of C. robusta was predicted using MaxEnt, a species distribution model. Two different RCP scenarios(4.5 and 8.5) were specified to predict the future distributions of C. robusta. The results showed that the biggest environmental factor affecting the distribution of C. robusta was the salinity as well as the highest distribution and potential habitats existent in the East Sea and around Jeju Island.

• Journal of Environmental Science International
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• v.30 no.9
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• pp.727-739
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• 2021

Measurements on mass size distribution of roadside aerosols were obtained in downtown Jeju City from July 2018 to May 2020 using an 8-stage cascade impactor sampler and the compositions of aerosols were analyzed. The mass size distribution of total aerosols was bimodal with aerosols existing in both the fine and coarse modes. The mass size distributions of Na⁺, Mg²⁺, Ca²⁺, Cl^-, NH₄⁺ and SO₄^2- were unimodal, whereas that of K⁺ was bimodal. For NO₃^-, the size distribution in winter and spring was bimodal with the peaks in both fine and coarse modes, whereas for summer and autumn the distribution was unimodal with a peak in the coarse mode. NH₄⁺ was found to co-exist with SO₄^2- in the fine mode with an average molar ratio of [NH₄⁺]/[SO₄^2-] equal to 2.05. Good correlation was observed between NO₃^- and NH₄⁺ in the fine mode particles in spring and winter. Based on the value of the marine enrichment factor for Cl^-, Mg²⁺, K⁺, Ca²⁺ and SO₄^2-, it may be inferred that a major part of the roadside aerosols in downtown Jeju City was largely contributed by terrigenous sources, although the influence of sea salt was normally present.

• Journal of The Geomorphological Association of Korea
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• v.27 no.2
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• pp.1-17
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• 2020

This study evaluated a debris landform distribution potential area map in the southwest region of the Korean peninsula. A GIS spatial integration technique and logistic regression method were used to produce a distribution potential area map. Seven topographic and environmental factors were considered for analysis and 28 different data set were combined and used to get most effective results. Moreover, in an accuracy assessment, the extracted results of the Distribution Potential area were evaluated by conducting a cross-validation module. Block stream showed the highest accuracy in the combination No. 6, and that DEM (digital elevation model) and TWI (topographic wetness index) have relatively high influences on the production of the Block stream Distribution Potential area map. Talus showed the highest accuracy in the combination No. 13. We also found that slope, TWI and geology have relatively high influences on the production of the Talus Distribution Potential area map. In addition, fieldwork confirmed the accuracy of the input data that were used in this study, and the slope and geology were also similar. It was also determined that these input data were relatively accurate. In the case of angularity, the block stream was composed of sub-rounded and sub-angular systems and Talus showed differences according to the terrain formation. Although the results of the rebound strain measurement using a Schmidt's hammer did not shown any difference in topographic conditions, it is determined that the rebound strain results reflected the underlying geological setting.