• Title/Summary/Keyword: 정적 지지력

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Analysis on Seismic Resistance Capacity of Hollow Concrete Block Reinforced Foundation Ground by Using Shaking Table Test (진동대 시험을 이용한 중공블록 보강 기초의 내진성능분석)

  • Shin, Eun-Chul;Lee, Yeun-Jeung;Yang, Tae Chul
    • Journal of the Korean Geosynthetics Society
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    • v.20 no.4
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    • pp.85-93
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    • 2021
  • The seventy percentage of Korean Peninsular is covered by the mountainous area, and the depth of west sea and south sea is relatively shallow. Therefore, a large scale land reclamation from the sea has been implemented for the construction of industrial complex, residental area, and port and airport facilities. The common problem of reclaimed land is consisted of soft ground, and hence it has low load bearing capacity as well as excessive settlement upon loading on the ground surface. The hollow concrete block has been used to reinforce the loose and soft foundation soil where the medium-high apartment or one-story industrial building is being planned to be built. Recently the earthquakes with the magnitude of 4.0~5.0 have been occurred in the west coastal and southeast coastal areas. Lee (2019) reported the advantages of hollow concrete block reinforced shallow foundation through the static laboratory bearing capacity tests. In this study, the dynamic behavior of hollow concrete block reinforced sandy ground with filling the crushed stone in the hollow space has been investigated by the means of shaking table test with the size of shaking table 1000 mm × 1000 mm. Three types of seismic wave, that is, Ofunato, Hachinohe, Artificial, and two different accelerations (0.154 g, 0.22 g) were applied in the shaking table tests. The horizontal displacement of structure which is situated right above the hollow concrete block reinforced ground was measured by using the LVDT. The relative density of soil ground are varied with 45%, 65%, and 85%, respectively, to investigate the effectiveness of reinforcement by hollow block and measured the magnitude of lateral movement, and compared with the limit value of 0.015h (Building Earthquake Code, 2019). Based on the results of shaking table test for hollow concrete block reinforced sandy ground, honeycell type hollow block gives a large interlocking force due to the filling of crushed stone in the hollow space as well as a great interface friction force by the confining pressure and punching resistance along the inside and outside of hollow concrete block. All these factors are contributed to reduce the great amount of horizontal displacement during the shaking table test. Finally, hollow concrete block reinforced sandy ground for shallow foundation is provided an outstanding reinforced method for medium-high building irrespective of seismic wave and moderate accelerations.

Dynamic Characteristics of Liquidity Filling Materials Mixed with Reclaimed Ash (매립석탄회를 혼합한 유동성 충진재의 동적거동특성)

  • Chae, Deokho;Kim, Kyoungo;Shin, Hyunyoung;Cho, Wanjei
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.4
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    • pp.5-11
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    • 2014
  • Recently, there have been various lifeline installations constructed in the underground space of urban area due to the effective use of land. For newly installed lifelines or the management of the installed lifelines, many construction activities of excavation and backfilling are observed. Around these area, there are possibilities of collapse or excessive settlement due to the leaking of the pipe or unsatisfactory compaction of backfill material. Besides, construction costs can be saved since the on-site soils are used. The application of this liquidity filling material is not only to the lifeline installation but also to underpin the foundation under the vibrating machinery. On the evaluation of the applicability of this method to this circumstance, the strength should be investigated against the static load from the machine load as well as the vibration load from the activation of the machine. In this study, the applicability of the liquidity fill material on the foundation under the vibrating machinery is assessed via uniaxial compression and resonant column tests. The liquidity filling material consisting of the on-site soils with loess and kaolinite are tested to investigate the static and dynamic characteristics. Furthermore, the applicability of the reclaimed ash categorized as an industrial waste is evaluated for the recycle of the waste to the construction materials. The experimental results show that the shear modulus and 7 day uniaxial strength of the liquidity filling material mixed with reclaimed ash show higher than those with the on-site soils. However, the damping ratio does not show any tendency on the mixed materials.

A Study on Dynamic Pile-Soil-Structure Interactions (말뚝-지반-구조물의 동섬 상호작용 연구)

  • Lee, In-Mo;Lee, Gwan-Ho;Kim, Yong-Jin
    • Geotechnical Engineering
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    • v.7 no.1
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    • pp.41-52
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    • 1991
  • A study of the effects of dynamic pile-soil-structure interactions on the response of super- structures, supported by group piles, are presented in this paper. The dynamic impedance functions of single pile generated by soil-pile interactions are obtained and compared among others using the methods proposed by Novak, Gazetas, and Kuhlemeyer, and using the equivalent cantilever method. Group pile effects are also considered by the following approaches : neglecting interaction effects : group efficiency ratio concept : static interaction approach . and dynamic interaction approach. The responses of a nuclear containment structure are obtained by using the elastic half-space analysis, based on the impedance functions mentioned above. Main conclusions drawn from this study are as follows : 1. The numerical results of the impedance functions calculated by each method were quite different : the Novak's was the smallest, and the Kuhlemeyer's the highest. Considering group effects, similar values in each approach were obtained for the stiffness : the difference was very big for the damping. 2. The top displacement of the structure was reduced by 20% or more by pile installations. However, the base shear force, the base moment, and the resonance frequency were increased by more than two times due to stiffening effect of the ground by pile installations. 3. Whether frequency dependant impedence functions or frequency independant functions were used, the responses of the structure were not so much affected by the choice of the impedance functions. 4. The reduction effect of the top displacement increased with the increase of the maximum ground acceleration.

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Development of Motion Control Techniques and Sea Trials of The Test Ship $\ulcorner$NARAE$\lrcorner$ (시험선 $\ulcorner$나래$\lrcorner$의 자세 제어 기술 개발 및 실해역 시험)

  • J.W. Kim;Y.G. Kim;G.J. Lee;C.Y. Lee
    • Journal of the Society of Naval Architects of Korea
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    • v.35 no.3
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    • pp.26-37
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    • 1998
  • In this study, the motion control techniques allied to the test ship NARAE are summarized and the results of sea trials are resented. NARAE adopted a hybrid hull form with lower hull and submerged foils. This type of ship has a substantial instability in heave, pitch and roll modes at the foil-borne stage due to little restoring force, so an active control is indispensable to keep the stability. 4-hydraulic actuators with servo valves were installed to drive foils, and several sensors were used to measure the motion of the ship. PID controller was adopted as a motion controller, and for the real-time control, Pentium-class industrial PC was used. Sea trials including take-off, landing, and banked turn maneuvering were carried out for a period of over 3 months and quite satisfactory results were obtained.

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Influence of academic stress, menstrual attitude on dysmenorrhea in high school girls (여고생의 학업 스트레스와 월경 태도가 월경곤란증에 미치는 영향)

  • Song, Ji-Ah
    • Journal of Industrial Convergence
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    • v.19 no.5
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    • pp.111-118
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    • 2021
  • This study was conducted to examine the academic stress, menstrual attitude, and dysmenorrhea of adolescents and to understand their effects on dysmenorrhea. The subjects of the study were high school girls and 131 people who agreed to participate in the study were analyzed. Correlation analysis shows that the more negative the person is about menstruation, the more severe the physical symptoms, the more active the action, and the greater the emotional change, the more severe the person experienced dysmenorrhea. Factors affecting dysmenorrhea in adolescents were physical symptoms and positive acceptance among menstrual attitudes, and 68.8 percent explained the variable. In conclusion, considering the positive acceptance of menstruation and physical symptoms of adolescents, it is necessary to develop educational programs that provide integrated knowledge to manage dysmenorrhea in school health, and further individual and multidimensional approaches such as emotional support programs for negatively experienced emotions.

The Effects of Mother's Anger and Depression on Young Children's Problem Behavior (어머니의 분노와 우울이 유아문제행동에 미치는 영향)

  • Song, Hyo-Suk;Park, So-Yun
    • The Journal of the Korea Contents Association
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    • v.21 no.7
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    • pp.609-618
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    • 2021
  • The purpose of this study was to investigate the effects of Mother's anger and depression on young children's problem behaviors. Data collection was from May 1, to July 1, 2019, and 244 Mother's entrusted infants and young children to three early childhood education institutions in Daejeon, Busan and Ulasn. The collected data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlation coefficient, and multiple liner regression analysis using SPSS/WIN 24.0. The results of this study showed that the young children's problem behavior had a statistically significant positive correlation with Mother's anger(r=.261, p=<.001), and depression(r=.435, p<.001). The multiple regression analysis showed that the factors that significantly affect the young children's problem behavior were depression(𝛽=16.57, p<.001) of the Mother's and the total explanatory power was 19.2%. Therefore, it provided implication for the need to develop parent education program to support the reduction of depression factors along with the emotional support Mother's.

Psychometric Properties of the Subjective Agingwell Scale (주관적 에이징웰 척도의 타당화)

  • Hong, Ji-Woong;Ju, Haewon
    • Journal of Digital Convergence
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    • v.19 no.11
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    • pp.415-424
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    • 2021
  • The purpose of the current study is to to examine the psychometric properties of the Subjective Agingwell Scale (SAS). Three hundred and forty two elders completed the SAS and the scales assessing subjective well-being, optimism, perceived control and adhering to healthy behavior. The 11-item SAS that displays good internal reliability and good fit to the three-factor model consisting of cognitive satisfaction, positive affect, and spiritual fullness. Correlational analyses with measures of subjective agingwell, subjective well-being, and optimism provide evidence for construct validity. Moreover, the results from hierarchical regression analyses show criterion-related validity of the SAS. This scale could be used in the field to measure and promote subjective agingwell.

Factors Affecting the attitude to death of Social Welfare Students (사회복지전공 대학생의 죽음에 대한 태도의 영향요인)

  • Kim, Bo-Mi
    • Journal of Digital Convergence
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    • v.19 no.11
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    • pp.545-553
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    • 2021
  • This research was conducted to examine the attitude to death, and identify factors influencing attitude to death, in social welfare students. Data were collected from 179 social welfare students. in two universities. Data were collected from April to June 2021 using structured questionnaires. Data collected were analyzed by descriptive statistics, t-test, ANOVA, Pearson correlations, and multiple regression analysis. The results indicated that meaning in life(r=.34, p=.001) had a significant positive association with attitude to death. And life satisfaction(r=.61, p<.001) and resilience(r=.65, p<.001) were positively correlated with attitude to death, The significant predictors of attitude to death, were grade(β=.21, p=.002) and life satisfaction(β=.22, p=.013), explaining 20.2% of the variance. Based on the study results, we suggest that it is necessary to develop counseling and attitude to death programs that can positively change the attitude of social welfare students

Comparison of Anger Expression Style and Cognitive Characteristics among Male adolescent game users depending on the level of Game Addiction and Engagement (게임중독 및 관여 수준에 따른 남자 청소년 게임사용집단의 분노표현양상과 인지적 특성 비교)

  • Lim, Jeeyoung
    • Journal of Digital Convergence
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    • v.15 no.10
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    • pp.339-348
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    • 2017
  • This study was conducted to examine the differences of anger expression style and cognitive characteristics among adolescents depending on the level of game addiction and game engagement. 420 high school boys were administered the Game Addiction/Engagement Scale, Behavioral Anger Response Questionnaire to measure anger expression style, and Irrational Belief Scale to measure cognitive characteristics. The results of correlation analyses showed that addiction had positive correlations with all the irrational belief factors and behavior anger factors except for assertion and avoidance. Engagement was positively correlated with all the variables except for direct anger-out, avoidance, and self-downing. Participants were divided into three groups depending on the level of addiction and engagement. Addiction high risk-low engagement group showed the lowest scores on support-seeking and the highest scores on diffusion and self-downing. Addiction high risk-high engagement group showed the highest scores on direct anger-out. Based on these findings, it was suggested that counselling strategies for adolescents at high risk of game addiction need to be varied depending on the level of game engagement.

Relationships between Specific self-efficacy, Family support, and Self-care performance for Patients with Stomach Cancer after Gastrectomy (위암 수술환자의 구체적 자기효능감, 가족지지와 자가간호수행의 관계)

  • Jeon, Yun Hwa;Park, Geum Ja
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.1
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    • pp.456-465
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    • 2018
  • This study was conducted to investigate the relationships among self-efficacy, family support, and self-care performance of gastric cancer surgery patients. The study was conducted from 11 October to 15 November 2013. Data were collected by self-report questionnaires from 121 patients who were diagnosed with stomach cancer and had undergone surgery at D university hospital in B city and were in follow-up care for 3 months to 5 years after surgery. Data were analyzed using SPSS/PC WIN 18.0 to obtain the percentage, average, mean rating, and standard deviation. In addition, t-test, ANOVA, Scheffe's test, Pearson's correlation and stepwise multiple regression were conducted. The degree of self-care performance in research targets showed significant differences by sex (t=-2.25, p=0.027), religion (F=3.67, p=0.028) and profession (F=4.17, p=0.008). Self-care performance was positively correlated (r=0.60, p<0.001) with the degree of specific self-efficacy. There was a significant difference in self-care performance by specific self-efficacy, religion and gender. The total explanatory power was 37.9% and the explanatory power of the degree of specific self-efficacy (${\beta}=0.53$) was greater than that of other factors. Therefore, it is necessary to provide interventions that improve specific self-efficacy to help patients with gastric cancer patients conduct self-care performance, and practical measures should be made with respect to religion and gender.