• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.4
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• pp.327-351
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• 2009

Laboratory tests are performed in this paper to investigate the brittle failure characteristics of over-stressed rocks taken in deep depth. Also, numerical simulation performed using that the so-called CWFS(Cohesion Weakening Frictional Strengthening) model is known to predict brittle failure phenomenon reasonably well. The most typical rock types of Korean peninsula - granite and gneiss - were used for testing. Results of uniaxial compression tests showed that the crack initiation stress was about 41 % to 42% of the uniaxial compressive strength regardless of rock types, where as, the crack damage stress of granite was about 75%, and that of gneiss was about 97%. Through the damage-controlled test, strength parameters of each rock were obtained as a function of damage degree. After the peak, the crack damage stress and the maximum stress were decreased, The cohesion was decreased and the friction angle was increased with increase of rock damage. Before reaching the peak, the elastic modulus was slightly increased, while decreased after the peak. Poisson's ratio was increased as the damage of rock proceeds. Comparison of uniaxial compression tests and damage-controlled tests shows the crack initiation stress estimated from the damage-controlled test fluctuated within the range of crack initiation stress obtained from the uniaxial compression test; the crack damage stress was less than that estimated from the uniaxial compression test. In order to predict the critical depth that brittle failure occurs, numerical simulations using the CWFS model were performed for an example site. Material parameters obtained from the laboratory tests mentioned above were used for CWFS simulation. Comparison between the critical depth predicted from the numerical simulation using the CWFS model and that predicted by using the damage index proposed by Martin et al.(l999), showed that critical depth cannot be reasonably predicted by the currently used damage index except for circular tunnels. A modified damage index was proposed by the author which takes the shape of tunnels other than circular into account.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.11 no.2
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• pp.101-111
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• 2016

Startup has lot of limitation such as time and budget shortage, and few human resources, and may be under the very stressful condition. Naturally in these context, there is always conflict among the startup team members, but the impact of conflict on teamwork or team performance has not been empirically tested. This study examines the relationship among the conflict, teamwork and team performance in startup context. Different two types of conflict and four factors of teamwork for team performance are identified from a literature review and tested; task conflict and relationship conflict as antecedents, teamwork was composed of communication, collaboration, coordination and cohesion, leading to team performance. 142 data points were collected from startup representatives to test these hypotheses. PLS data analysis indicated that the task conflict positively effects on all teamwork factors, but relationship conflict has statistically significant effect on only two teamwork factors, collaboration and coordination in negative relationship. Teamwork factors effects on team performance except communication. Based on the results, we proposed practically several team management skills for startup managers, leaders and even members, and explained theoretical contributions.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.89-98
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• 2010

Recently, many researches on bottom ash which is produced in the burning process of power plant are actively performed for its utilization for soil-subbase materials. In this paper, bottom ashes from 5 different power plants are prepared and several tests including compaction, CBR, and tri-axial compression are carried out for mixed bottom ash and weathered soil considering 3 replacement ratio of 30%, 50%, and 70%. Through the tests, CBR result over 20 are evaluated without plastic property, which shows availability of subbase material. With higher increase in replacement ratio of bottom ash, CBR of mixed soil increases due to the higher mechanical performance of bottom ash. However, replacement effects of bottom ash on friction angle and cohesion are evaluated to be little since bottom ash plays a little role in rearrangement of mixed soil. Bottom ash with a good mechanical property is evaluated to have reasonable bearing capacity which shows a good property for subbase materials.

• Journal of Families and Better Life
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• v.16 no.2
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• pp.123-136
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• 1998

The purpose of this study is to define the structure and characteristics of the time shared with parents and children. The three specific questions are asked. (1) How much time do parents and children share with? (2) What kind of effects do the demographic factors and the psychosocial factors have on the time shared with parents and children? (3) And how can the families be classified into different types according to the time shared with parents and children? For the empirically proved answers the 161 full0time housewife couples and the 174 wife employed couples in Seoul and Kyoungki-do are surveyed with a self reported time diary and a structured questionare. Such statistical methods as frequency percentage mean tobit analysis cluster analysis oneway ANOVA and Ducan's multiple range test are used to analize the data Main findings from this empirical study can be summarised like this. First the two largest parts of the time shared with parents and children are eating and TV atching. Second the eldest child's age degree of wife's education the number of children wife's employment status family income degree of the family cohesion the couple's attitude toward marriage and role salience are significantly related to the various kind of time shared with parents and children. Third the families are classified by the time shared with parents and children into three types. type 1: the family shared least time with type 2: the family shared passive leisure with type 3: the family shared active leisure with. Type 3 has very distinctive characteristics. This type of family's eldest child is youger than any other family's and this type of family has a full time housewife. And their family cohesion is higher and their couple's relationship is oriented more companionship.

• Journal of Ocean Engineering and Technology
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• v.19 no.4 s.65
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• pp.42-48
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• 2005

The sediment of Shihwa Lake contains an abundant quantity of cohesive sediments. The transport processes of the cohesive sediments are complex and difficult to predict, quantitatively. The cohesive sediments are the primary reason for the pollution of the environment and water quality in the coastal region. In this study, a column test has been performed. In order to quantify the settling velocities of sediment from Shihwa Lake, an experiment was conducted using a specially designed 1.8m tall settling column. A series of settling tests and physico-chemical property tests on Shihwa Lake cohesive sediments has been conducted to investigate the correlation between settling properties and their physico-chemical properties, which are represented as grain size distribution, mineralogical composition, and percentage oj organic contents. Experimental results of physico-chemical property tests show that Shihwa Lake sediments are relatively large in average grain $size(74\mu m)$ contain very small organic $material(6\%)$, and are dominantly composed of Quarts, which has relatively low cohesion. Thus, Shihwa Lake sediments might be specified as those whose settling properties are more influenced by gravity than cohesion. It is concluded that the magnitude of settling velocities of muddy sediments can be quite different, regionally, and it implies that field or laboratory experiments for settling velocity measurement should be preceded over the numerical modeling of muddy sediment transport, in order to obtain the reliable prediction results for a given specific site.

• Journal of The Korean Association For Science Education
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• v.22 no.4
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• pp.717-724
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• 2002

In this study. the effects of grouping by students' agreeableness in cooperative learning strategy applied to middle school science classes on their achievement. confidence, satisfaction, attitude toward science class, and cohesion of group members were investigated. One hundred and fifty-eight students were assigned to control group, homogeneous group and heterogeneous group, and taught about separation of mixture for 7 class hours. The results revealed that there was no significant difference in the achievement test scores. However, significant interaction between the instruction and the level of agreeableness were found in the satisfaction and the cohesion of group members. Students of higher agreeableness level in the homogeneous group were more satisfied with science class and cohesive. Students' attitude toward science class in the homogeneous group was also significantly higher than those in the other groups.

• Geomechanics and Engineering
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• v.15 no.1
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• pp.659-668
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• 2018

A series of direct shear tests were implemented on three different types of specimens (i.e., clean Perth sand, sand containing 10, 20 and 30% bentonite, sand containing 1, 3 and 5% slag, and sand containing 10, 20 and 30% bentonite with increasing percentages of added slag (1%, 3% and 5%). This paper focuses on the shear stress characteristics of clean sand and sand mixtures. The samples were tested under different three normal stresses (100, 150 and 200 kPa) and three curing periods of no curing time, 7 and 14 days. It was observed that the shear stresses of clean sand and mixtures were increased with increasing normal stresses. In addition, the use of slag has improved the shear strength of the sand-slag mixtures; the shear stresses rose from 128.642 kPa in the clean sand at normal stress of 200 kPa to 146.89 kPa, 154 kPa and 161.14 kPa when sand was mixed with 1%, 3% and 5% slag respectively and tested at the same normal stress. Internal friction angle increased from $32.74^{\circ}$ in the clean sand to $34.87^{\circ}$, $37.12^{\circ}$ and $39.4^{\circ}$ when sand was mixed with 1%, 3% and 5% slag respectively and tested at 100, 150, and 200 kPa normal stresses. The cohesion of sand-bentonite mixtures increased from 3.34 kPa in 10% bentonite to 22.9 kPa, 70.6 kPa when sand was mixed with 20% and 30% bentonite respectively. All the mixtures of clean sand, different bentonite and slag contents showed different behaviour; some mixtures exhibited shear stress more than clean sand whereas others showed less than clean sand. The internal friction angle increased, and cohesion decreased with increasing curing time.

• Journal of Industrial Convergence
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• v.20 no.4
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• pp.39-46
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• 2022

This descriptive survey study identified the factors influencing the abiliy of healthcare perceived by high school students. The survey was conducted from May 7, 2020, to Sep. 17, 2020 for 119 high school students in City D. SPSS WIN 22.0 program was used to for t-test and one-way ANOVA with Pearson's correlation coefficients and hierarchical regression analysis. The ability of healthcare perceived by high school students had a static correlation with the sub-domains of family function, that is, family cohesion(r=.65, p<.001) and family adaptability(r=.54, p<.001). For male students(β=.17, p=.012), those who reported a high level of perceived health status showed a high level of ability of healthcare(β=.25, p<.001). Significant influencing factors on high school students' health management ability were identified as gender (β=.17), their own health status perception (β=.23), and family cohesion (β=.45), and the explanatory power of the model was 50%. appear. Further research is hereby suggested for validation of the mediating role and effects of health care education programs to improve the family function perceived by high school students, encourage their practicing of health care management and help them to enter into healthy adulthood.

• Geomechanics and Engineering
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• v.28 no.5
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• pp.505-520
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• 2022

In recent years, geotextile-encased gravel columns (usually called stone columns) have become a popular method to increasing soil shear strength, decreasing the settlement, acceleration of the rate of consolidation, reducing the liquefaction potential and increasing the bearing capacity of foundations. The behavior of improved loose base-soil with gravel columns under shear loading and the shear stress-horizontal displacement curves got from large scale direct shear test are of great importance in understanding the performance of this method. In the present study, by performing 36 large-scale direct shear tests on sandy base-soil with different fine-content of zero to 30% in both not improved and improved with gravel columns, the effect of the presence of gravel columns in the loose soils were investigated. The results were used to predict the shear stress-horizontal displacement curve of these samples using support vector machines (SVM). Variables such as the non-plastic fine content of base-soil (FC), the area replacement ratio of the gravel column (Arr), the geotextile encasement and the normal stress on the sample were effective factors in the shear stress-horizontal displacement curve of the samples. The training and testing data of the model showed higher power of SVM compared to multilayer perceptron (MLP) neural network in predicting shear stress-horizontal displacement curve. After ensuring the accuracy of the model evaluation, by introducing different samples to the model, the effect of different variables on the maximum shear stress of the samples was investigated. The results showed that by adding a gravel column and increasing the Arr, the friction angle (ϕ) and cohesion (c) of the samples increase. This increase is less in base-soil with more FC, and in a proportion of the same Arr, with increasing FC, internal friction angle and cohesion decreases.

• Korean Journal of Psychosomatic Medicine
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• v.11 no.2
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• pp.182-195
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• 2003

Background: Marriage is one of the major life events and the primary source of individual happiness and meaning of life. It is not possible to predict who will marry whom and which marriage will be successful. Marital adjustment has significant influences on an individual and relationship functioning and is associated with mental health. Good marital quality may imply good general relationship. There are several factors that correlate with or predict good marital quality. Especially individual personality factors may be a major factor in achieving and maintaining marital stability, satisfaction and happiness. The aim of the present study was to investigate the possible relationship between dyadic adjustment and personality dimensions in urban married women. Methods: Dyadic Adjustment Scale, Eysenck's Personality Questionnaire, Beck Depression Inventory and State-Trait Anxiety Inventory were administered to 215 married women. Data analysis was based on 170 women who provided reliable informations. The descriptive statistics of demographic data and 4 scales were obtained. Then the possible relationships between each data were tested by calculating Pearson's product moment correlations. To test the effects of depression and anxiety on dyadic adjustment, stepwise multiple regression analysis was done. Results: Age and length of marriage were negatively correlated with affectional expression and dyadic cohesion. Educational level was positively correlated with total dyadic adjustment score and dyadic satisfaction. Family income was positively correlated with total dyadic adjustment score, dyadic consensus, dyadic satisfaction and dyadic cohesion. Different family type showed different total dyadic adjustment score, dyadic satisfaction and dyadic cohesion. Psychoticism was negatively correlated with total dyadic adjustment score, dyadic consensus, dyadic satisfaction, affectional expression and dyadic cohesion. Neuroticism was negatively correlated with total dyadic adjustment score, dyadic consensus, dyadic satisfaction and affectional expression. Extraversion and lie were not correlated with any factors. Beck Depression Inventory and State-Trait Anxiety Inventory scores were negatively correlated with total dyadic adjustment score, dyadic consensus, dyadic satisfaction, affectional expression and dyadic cohesion. The result of multiple regression analysis indicated that psychoticism was correlated with dyadic adjustment. Conclusion: These results showed that the demographic factors such as age, length of marriage, educational level, family income and family type were significantly correlated with dyadic adjustment. Psychoticism and neuroticism measured by Eysenck Personality Inventory were significantly correlated with dyadic adjustment. But the correlations with extraversion and lie were not significant. Especially correlation between neuroticism and dyadic adjustment seemed to be mediated by emotional state such as depression and anxiety. These findings suggest that personality factors may be involved in marital relationship and that clinician must consider personality aspect in dealing with marital problems. Future study about differences between control group and psychiatric patient group will be needed.