• Journal of Periodontal and Implant Science
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• v.34 no.2
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• pp.281-292
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• 2004

Periodontal defects of the furcation are characterized by several inherent anatomic factors that can make successful periodontal therapy difficult and results unpredictable. The severity and rate of occurrence of periodontal disease are directly related to the location of the furcation relative to the cementa-enamel junction and anatomical form of the root by limiting the accessibility and effectiveness of the periodontal instrumentation. This study investigated the reliability and accuracy of panoramic radiograph diagnoses of the periodontal state of mandibular molars, particularly regarding the diagnosis of furcation area periodontal defects, treatment planning, and prognosis prediction. This study examined a total of 110 teeth belonging to 33 subjects (19 male, 14 female) presenting with incipient to moderate periodontitis 4-7mmpocket depth. The alveolar bone level, length and width of the root trunk, and root separation angle were measured using the panoramic radiograph and compared to the results taken directly by retracting a full-thickness flap. The results of the study are as follows: 1. Data regarding the alveolar bone level of the mandibular first molar showed that the directly taken surgical measurements resulted in $5.1{\pm}0.9mm$ that was slightly deeper than the corresponding panoramic measurement resulted in $4.8{\pm}0.8mm$, but these differences were statistically insignificant (p>0.05). 2. The data of the directly taken surgical measurement of the mandibular second molar $(5.1{\pm}1.1mm)$ was slightly deeper than the corresponding panoramic measurement $(4.7{\pm}1.2mm)$, but these differences were statistically insignificant (p>0.05). 3. The measured values of the length and width of the mandibular first molar root trunks were determined to be $4.1{\pm}0.6mm$ and $7.3{\pm}0.9mm$, respectively, while the values of the mandibular second molar root trunks were determined to be $4.6{\pm}1.3mm$ and $7.6{\pm}0.9mm$ respectively. The differences between these values were found to be statistically significant (p<0.01). 4. The measured values of the root separation angle showed that the mandibular first molars averaged $34.5{\pm}4.4^{\circ}$, while the mandibular second molars averaged $23.0{\pm}10.0^{\circ}$. The differences between these values were found to be statistically significant (p<0.01).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.5
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• pp.1177-1189
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• 1994

This paper aims to develop the numerical model for prediction of the channel migration by analyzing of sediment and flow characteristics with patterns of channel in alluvial rivers. Flow in rivers constitutes to be the meandering or the braided form and rarely straight channel through morphologically stable patterns with mutual actions between the flowing water and bed materials. In order to develop the model for simulation of the channel migration, the channels are divided into two types with positive or negative sign by the direction of curvature radius of the centerline channel ($r_c$). That is, the single bend-channel consists of only one curvature of positive or negative sign and the multi-bend channel consists of two more curvatures of positive or negative sign, respectively. The model analyzes the sediment and flow characteristics under the influence of superelevation, spiral motion, irregularity in bed topography and depth-averaged velocity of channels. For reliability of this model, the single bend-channel and the multi bend channel are compared with experiment data in other models and the measured field data in the Keum-River, respectively. As a result, the both com parisians turn out to be excellent.

• 한국지구물리탐사학회:학술대회논문집
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• 2006.06a
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• pp.201-206
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• 2006

Earth sciences is undergoing a gradual but massive shift from description of the earth and earth systems, toward process modeling, simulation, and process visualization. This shift is very challenging because the underlying physical and chemical processes are often nonlinear and coupled. In addition, we are especially challenged when the processes take place in strongly heterogeneous systems. An example is two-phase fluid flow in rocks, which is a nonlinear, coupled and time-dependent problem and occurs in complex porous media. To understand and simulate these complex processes, the knowledge of underlying pore-scale processes is essential. This paper presents a new attempt to use pore-scale simulations for understanding physical properties of rocks. A rigorous pore-scale simulator requires three important traits: reliability, efficiency, and ability to handle complex microstructures. We use the Lattice-Boltzmann (LB) method for singleand two-phase flow properties, finite-element methods (FEM) for elastic and electrical properties of rocks. These rigorous pore-scale simulators can significantly complement the physical laboratory, with several distinct advantages: (1) rigorous prediction of the physical properties, (2) interrelations among the different rock properties in a given pore geometry, and (3) simulation of dynamic problems, which describe coupled, nonlinear, transient and complex behavior of Earth systems.

• Child Health Nursing Research
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• v.7 no.3
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• pp.280-297
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• 2001

The purpose of the study was to develop and test the model for the quality of life in mothers of children with nephrotic syndrome. A hypothetical model was constructed on the basis of previous studies and a review of literature. The conceptual framework was built around ten constructs. Exogenous variables included in this model were mother's health, father's health, marital intimacy, mother's attitude on children, economic state, side effect of steroid, severity of illness and social support. Endogenous variables were mother's burden and quality of life. Empirical data for testing the hypothetical model were collected by using a self-report questionnaire from 152 mothers of children with nephrotic syndrom at the outpatient clinics and in the hospital. The data was collected from May, 1999 to August, 1999.Reliability of the seven instruments was tested with Cronbach's alpha which ranged from 0.71 - 0.92.For the data analysis, SPSS 8.0 WIN program and LISREL 8.20 WIN program were used for descriptive statistics and covariance structural analysis. The results of covariance structural analysis were as follow :1. The hypothetical model showed a good fit with the empirical data. [x2 = .56, df = 3, p = .90(p>.05 ), GFI = .99, AGFI = .99, RMSR = .005.] 2. For the parsimony of model, a modified model was constructed by deleting 1 variable and excluding 2 paths according to the criteria of statistical significance and meaning.3. The modified model also showed a good fit with the data[x2 = 2.83, df = 7, p = .90( p>.05 ), GFI = 1.00, AGFI = .97, RMSR = .011].The result of the testing of the hypothesis were as follows : 1. Mother's health(γ21 = .26, t = 4.16), father's health(γ22 = .19, t = 2.92), marital intimacy(γ23 = .26, t = 4.13) and social support(γ28 = .12, t = 2.03) had a significant direct effect on the quality of life.2. Mother's burden(β21 = -.20, t = -3.10) had a significant negative direct effect on the quality of life.3. Mother's attitude on children(γ14 = -.34, t = .-4.57), mother's health(γ11 = -.22, t = -2.96) and side effect of steroid (γ16 = -.23, t = .-2.69) had a significant direct negative effect on the burden. The result of this study showed that mother's health, marital intimacy, mother's burden, father's health, and social support had a significant direct effect on the quality of life. Mother's attitude on children, mother's health, and side effect of steroid had a significant direct effect on mother's burden. These six variables, mother's health, marital intimacy, father's health, social support, mother's attitude on children and side effect of steroid were identified as relatively important variables. The results of this study suggest, it needed to determine the nursing intervention will alleviate mother's burden and promote a greater quality of life in mothers of children with nephrotic syndrom.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.8
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• pp.881-887
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• 2012

CFRP composite materials have been widely used in various fields of engineering because of their excellent properties. They show high specific stiffness and specific strength compared with metallic materiasl. Woven CFRP composite materials are fabricated from carbon fibers with two orientation angles ($0^{\circ}/90^{\circ}$), which influences the mechanical properties. Therefore, woven CFRP composite materials show different types of fracture behavior according to the load direction. Therefore, the fracture behavior of these materials needs to be evaluated according to the load direction when designing structures using these materials. In this study, we evaluate the fracture strength of plain-woven CFRP composite materials according to the load direction. We performed tests for six different angles (load direction: $0^{\circ}/90^{\circ}$, $30^{\circ}/-60^{\circ}$, $+45^{\circ}/-45^{\circ}$) and estimated the fracture strength for an arbitrary fiber angle by using the modified Tan's theory and harmonic function.

• Journal of Korean Academy of Nursing
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• v.30 no.2
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• pp.437-451
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• 2000

The purpose of this study was to estimate the forecast of bed demand for institutional long-term care for the elderly persons in Taegu Metropolitan City. The study subject was the total 1,877 elderly persons over age 65 living in Taegu. Among them 1,441 elderly persons were sampled from community and 436 were from the elderly admitted 5 general hospitals. Data collection was carried out by interview from 25 August to 25 December 1997. The measuring instrument of this study was the modified tool of CARE, MAI, PCTC, and ADL which were examined for validity and reliability. In order to forecast bed demand of Nursing Home, this study revised prediction techniques suggested by Robin. The results were as follows : 1. OLDi of Taegu City were 122,202 by the year 1998 and number of Low-Income Elderly Persons were 3,210. 2. The Level I : Senior Citizen Home $ADEMi=\frac{AQi * ASTAYi}{365 * AOCUi}$. AQi = OLDi * LADLi * NASi * ALONi * LIADLi * AUTILi. Predicted number of bed demand for Home Based. Elderly Persons were 4,210 and Low-Income Elderly Persons were 1,081 and Total Elderly Persons were 5,291 by the year 1998, 6,343 by the year 2000 and 8,351 by the 2005. 3. The Level II : Nursing Home $BDEMi=\frac{(BQ1i+BQ2i) * BSTAYi}{365 * BOCUi}$. BQ1i = OLDi * HADLi * ALONi * HIADLi BQ2i = OLDi * HADLi * FAMi * OBEDi Predicted number of demand for Total Elderly Persons were 668 by the year 1998, 802 by the year 2000 and 1,055 by the 2005. 4. The Level III : Nursing Home $CDEMi=\frac{COLDi * HDISi * CUTILi * CSTAYi}{365 * COCUi}+OQi/10$ Predicted number of demand for Total Elderly Persons were 1,899 by the year 1998, 2,311 by the year 2000 and 3,003 by the 2005. 5. Predicted number of bed demand of long-term care facilities in the year 1998 according to Levels were 4.3% among elderly persons in Taegu by Level I, 0.5% by Level II and 1.5% by Level III. Number of elderly persons in current long-term care facilities were 458 in LevelI I,284 in Level II. 6. Deficit number of bed demand of long-term care facilities were 4,833 in Level I, 384 in Level II, 1,899 in Level III for the elderly persons in Taegu Metropolitan City.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.4
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• pp.201-212
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• 2016

A Wind resource assessment and optimal micrositing of wind turbines were implemented for the development of an onshore wind farm of 30 MW capacity on Gadeok Island in Busan, Republic of Korea. The wind data measured by the automatic weather system (AWS) that was installed and operated in the candidate area were used, and a reliability investigation was conducted through a data quality check. The AWS data were measured for one year, and were corrected for the long term of 30 years by using the modern era retrospective analysis for research and application (MERRA) reanalysis data and a measure- correlate-predict (MCP) technique; the corrected data were used for the optimal micrositing of the wind turbines. The micrositing of the 3 MW wind turbines was conducted under 25 conditions, then the best-optimized layout was analyzed with a various wake model. When the optimization was complete, the estimated park efficiency and capacity factor were from 97.6 to 98.7 and from 37.9 to 38.3, respectively. Furthermore, the annual energy production (AEP), including wake losses, was estimated to be from 99,598.4 MWh to 100,732.9 MWh, and the area was confirmed as a highly economical location for development of a wind farm.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.193-202
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• 2018

This paper proposed a crack spacing calculation formulation which is an important parameter for calculating the crack width, that is the main factor for verification of serviceability limit states and durability performance evaluation of reinforced concrete members. The basic equation of average crack spacing is derived by considering the bond characteristics which is the governing equation for the analysis of cracking behavior in reinforced concrete members. In order to consider the effect of the cover thickness and concrete compressive strength, the crack spacing measured in 124 direct tensile tests performed by several researchers was analyzed and each coefficient was proposed. And, correlation analysis was performed from 80 specimen data where the maximum and average crack spacing were simultaneously measured, and a correlation coefficient that can easily predict the maximum crack spacing from the average crack spacing was proposed. The results of the proposed average crack spacing equation and maximum crack spacing correlation were compared with those current design code specification. The comparisons of proposed equations and the Korean design codes show that the proposed formulation for the average crack spacing and the maximum crack spacing improves the accuracy and reliability of prediction compared to the corresponding provisions of the Korean Concrete Structural Design Code and Korean Highway Bridge Design Code (Limit States Design).

• The Korean Journal of Rehabilitation Nursing
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• v.1 no.1
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• pp.61-71
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• 1998

Defining prediction variables related to metamemory for the adults in aging process has worthwhile meaning from the perspective that the produced results can be helpful to reducing the difficulty of memorizing efforts and it can also enhance quality of life of aged. This study attempted to analysis relationship between perceived health status, depression, memory self-efficacy and meta memory for the subjects of middle age and old age adults. This study was designed by adopting descriptive correlational analysis method for the 468 middle and old age adults who are living in Seoul. Samples were selected by convenience sampling. Data collection was done over 1 month period in june 1998. The instruments used in this study were health status measuring scale including depression measuring scale, memory self efficacy measuring scale and metamemory measuring scale which were verified for reliability. Data collected were analized by using SPSS for frequency, Peason correlation, t-test and ANOVA according to the variables character and the study purposes. Results of the study were as follows. 1. Relationship between perceived health status, depression, memory self-efficacy and metamemory. Relational analyses between perceived health status, depression, memory self-efficacy and metamemory supported the hypotheses of 1st, 2nd and 3rd(p < .01). These results suggested that the aged perceived great health status then their memory self-efficacy, and metamemory showed the high scores. In the case of depression when its level became decreased metamemory was inclined to increased. Thus, it is identified that strong relationship exists between these variables. 2. Perceived health status, depression, memory self-efficacy by subject's general characteristics. Scores of perceived health status were high in the group of man compared to the group of women, and also highly educated group showed great perceived health status. Group of persons having occupation showed high score of perceived health status and low depression score. The score of memory self-efficacy and metamemory showed higher in the middle aged than the old aged. The high scores of memory self-efficacy and metamemory were found in the group of highly educated people and who have continuing education. The high scores of memory self-efficacy were found in the group of persons having their job and high metamemory scores found in the group of persons having religion. In summary, the greater perceived health status and memory self-efficacy, the more metamemory scores were likely increased and the more depression level was decreased, the more metamemory was likely increased. Also it was found that general characteristics like educational level, continuing education and religion influenced the metamemory of the aged. Therefore, prevention the aged from getting depression and activation of health promotion are needed to delay time of memory loss.

• International Journal of Highway Engineering
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• v.19 no.6
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• pp.67-74
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• 2017

PURPOSES : In this study, a three-dimensional nonlinear finite element analysis (FEA) model for airport concrete pavement was developed using the commercial program ABAQUS. Users can select an analysis method and set the range of input parameters to reflect actual conditions such as environmental loading. METHODS : The geometrical shape of the FEA model was chosen by considering the concrete pavement located in the third-stage construction site of Incheon International Airport. Incompatible eight-node elements were used for the FEA model. Laboratory test results for the concrete specimens fabricated at the construction site were used as material properties of the concrete slab. The material properties of the cement-treated base suggested by the Federal Aviation Administration(FAA) manual were used as those of the lean concrete subbase. In addition, preceding studies and pavement evaluation reports of Incheon International Airport were referred for the material properties of asphalt base and subgrade. The kinetic friction coefficient between the concrete slab and asphalt base acquired from a preceding study was used for the friction coefficient between the layers. A nonlinear temperature gradient according to slab depth was used as an input parameter of environmental loading, and a quasistatic method was used to analyze traffic loading. The average load transfer efficiency obtained from an Heavy falling Weight Deflectomete(HWD) test was converted to a spring constant between adjacent slabs to be used as an input parameter. The reliability of the FEA model developed in this study was verified by comparing its analysis results to those of the FEAFAA model. RESULTS : A series of analyses were performed for environmental loading, traffic loading, and combined loading by using both the model developed in this study and the FEAFAA model under the same conditions. The stresses of the concrete slab obtained by both analysis models were almost the same. An HWD test was simulated and analyzed using the FEA model developed in this study. As a result, the actual deflections at the center, mid-edge, and corner of the slab caused by the HWD loading were similar to those obtained by the analysis. CONCLUSIONS : The FEA model developed in this study was judged to be utilized sufficiently in the prediction of behavior of airport concrete pavement.