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A Study on the Allowable Bearing Capacity of Pile by Driving Formulas (각종 항타공식에 의한 말뚝의 허용지지력 연구)

  • 이진수;장용채;김용걸
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2002.03a
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    • pp.197-203
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    • 2002
  • The estimation of pile bearing capacity is important since the design details are determined from the result. There are numerous ways of determining the pile design load, but only few of them are chosen in the actual design. According to the recent investigation in Korea, the formulas proposed by Meyerhof based on the SPT N values are most frequently chosen in the design stage. In the study, various static and dynamic formulas have been used in predicting the allowable bearing capacity of a pile. Further, the reliability of these formulas has been verified by comparing the perdicted values with the static and dynamic load test measurements. Also in cases, these methods of pile bearing capacity determination do not take the time effect consideration, the actual allowable load as determined from pile load test indicates severe deviation from the design value. The principle results of this study are summarized as follows : A a result of estimate the reliability in criterion of the Davisson method, in was showed that Terzaghi & Peck > Chin > Meyerhof > Modified Meyerhof method was the most reliable method for the prediction of bearing capacity. Comparisons of the various pile-driving formulas showed that Modified Engineering News was the most reliable method. However, a significant error happened between dynamic bearing capacity equation was judged that uncertainty of hammer efficiency, characteristics of variable , time effect etc... was not considered. As a result of considering time effect increased skin friction capacity higher than end bearing capacity. It was found out that it would be possible to increase the skin friction capacity 1.99 times higher than a driving. As a result of considering 7 day's time effect, it was obtained that Engineering News. Modified Engineering News. Hiley, Danish, Gates, CAPWAP(CAse Pile Wave Analysis Program ) analysis for relation, respectively, $Q_{u(Restrike)}$ $Q_{u(EOID)}$ = 0.971 $t_{0.1}$, 0.968 $t_{0.1}$, 1.192 $t_{0.1}$, 0.88 $t_{0.1}$, 0.889 $t_{0.1}$, 0.966 $t_{0.1}$, 0.889 $t_{0.1}$, 0.966 $t_{0.1}$

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Stochastic finite element based seismic analysis of framed structures with open-storey

  • Manjuprasad, M.;Gopalakrishnan, S.;Rao, K. Balaji
    • Structural Engineering and Mechanics
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    • v.15 no.4
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    • pp.381-394
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    • 2003
  • While constructing multistorey buildings with reinforced concrete framed structures it is a common practice to provide parking space for vehicles at the ground floor level. This floor will generally consist of open frames without any infilled walls and is called an open-storey. From a post disaster damage survey carried out, it was noticed that during the January 26, 2001 Bhuj (Gujarat, India) earthquake, a large number of reinforced concrete framed buildings with open-storey at ground floor level, suffered extensive damage and in some cases catastrophic collapse. This has brought into sharp focus the need to carry out systematic studies on the seismic vulnerability of such buildings. Determination of vulnerability requires realistic structural response estimations taking into account the stochasticity in the loading and the system parameters. The stochastic finite element method can be effectively used to model the random fields while carrying out such studies. This paper presents the details of stochastic finite element analysis of a five-storey three-bay reinforced concrete framed structure with open-storey subjected to standard seismic excitation. In the present study, only the stochasticity in the system parameters is considered. The stochastic finite element method used for carrying out the analysis is based on perturbation technique. Each random field representing the stochastic geometry/material property is discretised into correlated random variables using spatial averaging technique. The uncertainties in geometry and material properties are modelled using the first two moments of the corresponding parameters. In evaluating the stochastic response, the cross-sectional area and Young' modulus are considered as independent random fields. To study the influence of correlation length of random fields, different correlation lengths are considered for random field discretisation. The spatial expectations and covariances for displacement response at any time instant are obtained as the output. The effect of open-storey is modelled by suitably considering the stiffness of infilled walls in the upper storey using cross bracing. In order to account for changes in soil conditions during strong motion earthquakes, both fixed and hinged supports are considered. The results of the stochastic finite element based seismic analysis of reinforced concrete framed structures reported in this paper demonstrate the importance of considering the effect of open-storey with appropriate support conditions to estimate the realistic response of buildings subjected to earthquakes.

A Study on the Comparison Between China's Anti-Dumping System and WTO Agreement (중국 반덤핑 법규와 WTO 규범과의 적합성 비교 연구)

  • Shin, Sung-Shik;Choi, Hae-Bum
    • International Commerce and Information Review
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    • v.13 no.4
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    • pp.323-349
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    • 2011
  • As China is one of WTO member nations, It has an obligation to have to certainly keep a standard regarding anti-dumping systems deciding in WTO agreements. Nonetheless the Chinese anti-dumping laws is causing legal uncertainty because of insufficient details regulations about the account of dumping margins, the termination of an investigation in case of negligible imports, and sunset review And a part of regulations are disagreed with WTO anti-dumping agreement about price undertakings. Therefore, South Korea should indicate them and urge the Chinese government to revise them so that its anti-dumping Law is agreed with WTO agreement. Aside from this, if the anti-dumping investigation is initiated, South Korea government must observe how the Chinese authorities operates its anti-dumping law that do not agree with WTO agreement, and should prepare the countermeasure accordingly. The analysis of this study is concentrated on the compatibility of the WTO anti-dumping agreement with China's interpretation of the antidumping policy and public law. Also, Including our export company, government agencies, academic circles being related, and international trade advisory agencies must expand opportunity of information sharing.

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EFFECT OF A DESENSITIZER ON DENTINAL BOND STRENGTH IN CEMENTATION OF COMPOSITE RESIN INLAY (레진 인레이 합착시 지각과민처리제의 사용이 상아질 결합강도에 미치는 영향)

  • Han, Sae-Hee;Cho, Young-Gon
    • Restorative Dentistry and Endodontics
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    • v.34 no.3
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    • pp.223-231
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    • 2009
  • The purpose of this study was to evaluate the effect of a desensitizer on dentinal bond strength in cementation of composite resin inlay. Fifty four molar teeth were exposed the occlusal dentin. Class I inlay cavities were prepared and randomly divided into six groups. Control group: no agent, Group 1 : Isodan, Group 2 : One-step, Group 3 : All-Bond SE, Group 4 : Isodan + One-step, Group 5 : Isodan + All-Bond SE. Desensitizing agent and dentin bonding agents were applied immediately after the completion of the preparations. Impressions were then made. The composite resin inlays (Tescera, Bisco) were fabricated according to the manufacturers' guidelines. Cementation procedures followed a standard protocol by using resin cement (Bis-Cem, Bisco). Specimens were stored in distilled water at $37^{\circ}C$ for 24 hours. All specimens were sectioned to obtained sticks with $1.0{\times}1.0\;mm^2$ cross sectional area. The microtensile bond strength (${\mu}TBS$) was tested at crosshead speed of 1 mm/min. The data was analyzed using one way ANOVA and Tukey's test. Scanning electron microscopy analysis was made to examine the details of the bonding interface, 1. Group 1 showed significantly lower ${\mu}TBS$ than other groups (p<0.05). 2. There was no significant difference between the ${\mu}TBS$ of Group 3 and Group 5. 3. The ${\mu}TBS$ of Group 4 showed significantly lower than that of Group 2 (p<0.05). In conclusion, a desensitizer (Isodan) might have an adverse effect on the bond strength of composite resin inlay to dentin.

The Linguistic Properties Comparison between nongifted children and Gifted children (일반아동과 영재아동의 언어적 특성 비교)

  • Jang, Hye-Ja;Kim, Hye-Ok;Un, Hyeon-Seon;Jo, Bok-Hui
    • Journal of Gifted/Talented Education
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    • v.10 no.2
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    • pp.25-46
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    • 2000
  • These purposes are to have a necessity to be educated for the linguistic gifted among many gifted in speedy changeable age, and to find out what differences are of properties between the linguistic gifted children and nongifted children through comparing/analysing to gifted children any nongifted children using performance evaluation on writer's ability. Therefore, it intends to use as a assisting material in order to develop ability and properties of the linguistic gifted children and nongifted children as well. The studying details are 1) to compare/analyze thinking ability between the linguistic gifted children and nongifted children 2) to find out differences of thinking ability for unrealistic reasoning between the linguistic gifted children and nongifted children. The studying subjects had been chosen 3 children as a first grade in 'C' Gifted Academy and 3 children as a first grade in an elementary school from June 3, 1999 to June 12, 1999. The studying instrument was an evaluation of linguistic properties certification(Project Spectrum : Krechevsky,'1994). It had got a frequency calculation, average and standard deviation through the material anylzing with the program SPSSWIN. The conclusions are as belows, First, as a result of performance evaluation on writer's ability to gifted children and nongifted children, the gifted children were outstandingly shown the linguistic ability getting much higher score than nongifted children in respect of vocabulary level, structure of writing, and consistency/logicality of theme. Second, it was shown the gifted children had diffusing thought than nongifted children through the esthetic question and impformation memories with listening to the realistic juvenil story and the unrealistic juvenile story.

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The Effect of Self-leadership Program for Nursing Students on Empowerment, Self-directed Learning, and Happiness (간호대학생을 위한 셀프리더십 프로그램이 임파워먼트, 자기주도적 학습능력, 행복감에 미치는 효과)

  • Park, Jung Ha
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.7
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    • pp.61-67
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    • 2019
  • The purpose of this study is to apply self-leadership program using films to nursing students and to confirm the effects of self-leadership, empowerment, self-directed learning and happiness. The study participants were 60 nursing students, the data was collected from March 7, to June 13, 2017. The data was analyzed by frequency, percentage, mean, standard deviation, and paired t-test using SPSS WIN 24.0 computer program. The self-leadership program consisted of 13 sessions, and 14 films were used for self-management, self-training, and self-branding. The self-leadership of nursing students was significantly increased after education(t=-4.38, p<.001). In details, behavior-focused strategies, natural-reward strategies, and constructive thought pattern strategies were all significant. Empowerment also increased significantly after education(t=-5.83, p<.001), and personal skills, collective recognition, and self-determination were all significant. Self-directed learning were high after education(t=-3.31, p=.002), and learning plans and learning practices were significant. In addition, the happiness of nursing college students was significantly higher after education(t=-4.49, p<.001). As a result of this study, self-leadership program using movies can improve self-leadership, empowerment, self-directed learning and happiness of nursing students and It will be possible to apply as educational intervention in the future.

Structural Behavior of RC Beams with Headed Bars using Finite Element Analysis (유한요소해석 기반 확대머리 이형철근 상세 따른 RC보의 구조성능 효과 분석)

  • Kim, Kun-Soo;Park, Ki-Tae;Park, Chang-Jin
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.25 no.5
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    • pp.40-47
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    • 2021
  • In this study, the structural behavior by the details of the lap region with the headed bar was estimated through finite element analysis. To solve the finite element analysis of the anchorage region with complex contact conditions and nonlinear behavior, a quasi-static analysis technique by explicit dynamic analysis was performed. The accuracy of the finite element model was verified by comparing the experimental results with the finite element analysis results. It was confirmed that the quasi-static analysis technique well reflected the behavior of enlarged headed bar connection. As a result of performing numerical analysis using 21 finite element models with various development lengths and transverse reinforcement indexes, it was confirmed that the increase of development length and transverse reinforcement index improved the maximum strength and ductility. However, to satisfy the structural performance, it should be confirmed that both design variables(development length and transverse reinforcement index) must be enough at the design criteria. In the recently revised design standard(KDS 14 20 52 :2021), a design formula of headed bar that considers both the development length and the transverse reinforcing bar index is presented. Also the results of this study confirmed that not only the development length but also transverse reinforcing bars have a very important effect.

Hysteretic Behavior of Diagonally Reinforced Concrete Coupling Beams According to Aspect Ratio and Volume Fraction of Steel Fiber Under Cyclic Loading (반복하중을 받는 대각보강된 철근콘크리트 연결보의 강섬유 형상비와 혼입률에 따른 이력거동)

  • Choi, Ji-Yoon;Son, Dong-Hee;Bae, Baek-Il;Choi, Chang-Sik
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.26 no.3
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    • pp.84-91
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    • 2022
  • In this study, an experimental study was conducted to analyze the hysteresis behavior according to the steel fiber aspect ratio and volume fraction of diagonally reinforced concrete coupling beams under to cyclic loading. The aspect ratio and volume fraction of the steel fibers were set as the main variables, and 4 specimens were fabricated in which the amount of transverse reinforcement of the coupling beam suggested in the domestic building structural standard was relaxed by about 53%. In the experiment, cyclic loading experiments were performed in the displacement control method in accordance with ACI 374.2R-13, and as a result of the experiment, it was found that all specimens containing steel fibers exceeded the nominal shear strength suggested by the current structural standards. As the aspect ratio of the steel fibers increased, the steel fibers prevented the buckling of the diagonal reinforcement, and the bridging effect of the steel fibers held the crack surface of the concrete. The shear strength, stiffness reduction and energy dissipation capacity of the specimens containing steel fibers were superior to those of the Vf0 specimens without steel fibers. Therefore, it is judged that the steel fiber reinforced concrete can relieve the details of the transverse reinforced.

High Resolution Seismic Reflection Method Using S-Waves: Case Histories for Ultrashallow Bedrocks (S파를 이용한 고해상도 탄성파 반사법 탐사: 지반표층부에 대한 적용사례)

  • Kim Sung-Woo;Woo Ki-Han;Han Myung-Ja;Jang Hae-Dong;Choi Yong-Kyu;Kong Young-Sae
    • Journal of the Korean Geotechnical Society
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    • v.22 no.4
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    • pp.41-49
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    • 2006
  • This paper demonstrates the feasibility of using shallow S-wave, high-resolution seismic reflection surveys to characterize geological structure and stratigraphy of basement rocks for civil engineering purposes. S-wave seismic reflections from depths less than 20 m were recorded along the top of steep readout slopes. Seismic reflection data were recorded using a standard CDP acquisition method with a 24-channel seismograph and a sledge-hammer SH-wave source. The data were acquired using a split-spread source-receiver geometry with a 2 m shot-and-receiver interval, and then were processed to enhance S/N ratio of the data, to improve resolvable power of the seismic section, and to get velocity information of the basement rock. The final seismic reflection profiles using the CDP technique has imaged surfaces as shallow as less than 1m and resolved beds as thin as 1m. The migrated reflection sections possess sufficient quality to correlate the prominent reflection events to the bedding planes and faults identified on the readout outcrops. Similar S-wave reflection surveys could also be used to produce the necessary details of a geological structure of shallow bedrocks to pinpoint optimum locations for monitor wells of civil engineering purposes.

The Relationship of Drinking and Dampness-Phlegm Pattern in Acute Stroke Patients (급성기 중풍 환자의 음주 여부와 습담 변증의 상관관계 연구)

  • Yeo, Hyeon-su;Rhee, See-hyung;Hsia, Yu-chun;Jung, Ki-yong;Baik, Jong-woo;Choi, You-kyung;Kim, Dong-woo;Park, Jong-hyung;Cho, Ki-ho;Ko, Seung-gyu;Han, Chang-ho;Bang Ok-Sun;Jun, Chan-yong
    • The Journal of the Society of Stroke on Korean Medicine
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    • v.8 no.1
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    • pp.17-21
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    • 2007
  • Objectives : This study was done to investigate the relationship of drinking and Dampness-Phlegm pattern in acute stroke patients. Methods : In the time of period Mar. 2007 to Jun. 2007, 103 patients with stroke admitted in the department of Internal Medicine of Kyungwon University Seoul Oriental Medical Hospital, Kyungwon University Incheon Oriental Medical Hospital, Kyunghee University Oriental Medical Hospital, Dongguk Il-san Oriental Medical Hospital were included. Patients were hospitalized within a month after the onset of stroke. Stroke patients were interviewed by residents who studied standard operation procedures in Fundamental Study for Standardization and Objectification of Differentiation and Pattern Identification of Syndrome of Oriental Medicine for Stroke. A questionnaire was completed by a question-and-answer form between patients and residents after explanation details to patients and the agreement of patients. Results : Drinking subjects have tendency of Dampness-Phlegm Pattern(p=0.096), but don't have statistical significance(p<0.05). Conclusions : In this study, we found the relationship of drinking and Dampness-Phlegm Pattern. To acquire more concrete conclusion on this theme, we need more research.

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