• Steel and Composite Structures
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• 제26권3호
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• pp.375-386
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• 2018

Existing design codes for steel-concrete composite structures give only general information about the shear connection provided by headed studs in group arrangement. Grouting of the openings in prefabricated concrete slabs, where the grouped headed studs are placed in the deck pockets is alternative to cast-in-place decks to accomplish fast execution of composite structures. This paper considers the possibility to reduce the distance between the studs within the group, bellow the Eurocode limitations. This may lead to increased competitiveness of the prefabricated construction because more studs are placed in the group if negative effectives of smaller distances between studs are limited. The main purpose of this work is to investigate these limits and propose an analytical calculation model for prediction of the shear resistance of grouped stud arrangements in the deck pockets. An advanced FEA model, validated by results of push-out experiments, is used to analyze the shear behavior of the grouped stud with smaller distance between them than recommended by EN 1994-1. Calculation model for shear resistance, which is consistent with the existing Eurocode rules, is proposed based on a newly introduced equivalent diameter of the stud group, $d_G$. The new calculation model is validated by comparison to the results of FE parametric study. The distance between the studs in the longitudinal direction and the number of stud rows and columns in the group are considered as the main variables.

• Advances in pediatric surgery
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• 제6권1호
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• pp.1-9
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• 2000

Despite of advances in perinatal management and treatment modalities congenital diaphragmatic hernia(CDH) remains a frustrating problem. Although the sheep has proven to be a reliable experimental model for the production of intrauterine CDH, the rabbit may have some advantages. These include lower cost, smaller body size, year-round availability, high number of fetuses per pregnancy, and short gestational period. To evaluate the feasibility of the rabbit model of CDH, twenty-seven pregnant New Zealand rabbits were utilized. Hysterotomy and an operative procedure for creating a diaphragmatic defect on gestational day 24 or 25, in two fetuses of each pregnant rabbit were performed. In one fetus of one cornu of the uterus, the left fetal diaphragm was excised through an open thoracotomy(DH group). In another fetus in the other cornu, CDH was created and the trachea clipped(Surgiclip, USSC, Norwalk, Conn., USA) (TL group). Delivery was by Cesarean section on 30 days of gestation. Among twenty- seven pregnant rabbits, 12 in the DH group and eight in the TL group were born alive. The most common herniated organ was the left lobe of the liver. In thee DH group, the lungs were hypoplastic with decreased lung weight/body weight ratio, reduced numbers of alveoli, thicker media of the pulmonary arteries, and immature alveoli. In TL group, the alveoli were more mature and did not differ from the control animals. In conclusion, (1) pulmonary hypoplasia develops in the fetal rabbit diaphragmatic hernia model and (2) simultaneous tracheal ligation prevents pulmonary hypoplasia.

• 대한본초학회지
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• 제28권5호
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• pp.33-38
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• 2013

Objectives : The aim of this study was to examine anti-thrombotic effect of traditional herbal extracts in a rat model of ferric chloride ($FeCl_3$)-induced carotid arterial thrombosis. Methods : Thirty minutes prior to a 35% $FeCl_3$ application, Sprague Dawley(SD) rats were injected with the 10 types of traditional herbal extracts (100mg/kg, intraperitoneal injection), respectively. The effect of these herbal extracts was examined for time to occlusion(TTO) using the Laser doppler flow meter and measured for thrombus weight (TW) in $FeCl_3$-induced thrombosis model. Results : In the TTO, Salvia miltiorrhiza (Sm, $2.30{\pm}0.28$ min, p<0.001) and Santalum album (Sa, $2.19{\pm}0.19$ min, p<0.001) showed significantly delayed TTO more than twice compared with Saline-treated group. Cnidium officinale (Co), Psoralea corylifolia (Pc), Scutellatia baicalensis (Sba), Panax notoginseng (Pn), Angelica tenuissima (At), Scrophularia buergeriana (Sbu), Rhus verniciflua (Rv) and Picrasma quassioides (Pq), except for Rhus verniciflua (Rv) also meaningfully impeded TTO more than one fold. In addition, Salvia miltiorrhiza, Santalum album, Cnidium officinale, Psoralea corylifolia and Scutellatia baicalensis significantly reduced TW more than 10% compared with Saline-treated group. Especially, Salvia miltiorrhiza and Santalum album showed the most excellent anti-thrombotic effect among the 10 herbal extracts tested on the restoration of altered TTO and TW. Conclusions : These results suggest that Sm and Sa extracts have outstanding anti-thrombotic effect in $FeCl_3$-induced thrombosis model and is potentially useful as herbal medicines for the treatment and prevention of thrombosis.

• 한국간호교육학회지
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• 제30권1호
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• pp.5-18
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• 2024

Purpose: This study aimed to identify whether there is a difference between an online-based community psychiatric nursing practice program with the ARCS model and a conventional community psychiatric nursing practice program in promoting nursing students' learning motivation, knowledge of community psychiatric nursing, communication skills, and learning self-efficacy. Methods: This study used a quasi-experimental design with a non-equivalent control group. The participants were 44 nursing students at three nursing colleges in Gyeongsangbuk-do. The experimental group was provided the online-based community psychiatric nursing practice program with ARCS model, while the control group was provided the conventional community psychiatric nursing practice program from July 9, to September 3, 2022. Both groups received practice training 8 hours a day, 5 days two weeks. The collected data were analyzed using the exact χ², Mann-Whitney U-test, and Quade's two-way ANCOVA with the IBM SPSS Statistics 28.0 program. Results: The results of the comparison of an experimental group training with the online-based community psychiatric nursing practice program with ARCS model and a control group training with the conventional community psychiatric nursing practice program showed that, there was no statistically significant difference between the two groups in learning motivation knowledge of community psychiatric nursing, and learning self-efficacy. However, communication skills were statistically significantly higher in the experimental group (F=6.23, p=.017). Conclusion: The online-based community psychiatric nursing practice program with ARCS model can be used as a substitute learning to improve community psychiatric nursing capabilities in situations when clinical practice is suspended due to infectious diseases such as coronavirus disease 2019 or when is a shortage of community psychiatric nursing practice institutions.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 제5회 압연심포지엄 신 시장 개척을 위한 압연기술
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• pp.368-377
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• 2004

A mathematical model was developed for the prediction of the average temperature and RDT(RM Delivery temperature) in a roughing mill. The model consisted of three parts as follows (1) The intermediate numerical model calculated the deformation and heat transfer phenomena in the rolling: region by steady state FEM and the heat transfer phenomena in the interpass region by unsteady state FEM (2) The Off-line prediction model was derived from non-linear regression analysis based on the results of intermediate numerical model considering the various rolling conditions, (3) Using the heat flux in rolling region, temperature profile along thickness direction was calculated. For validation of the presented model, the rolling force per pass and RDT measued in on-line process was compared with those of model and the results showed close agreement with the existing data. In order to demonstrate the effectiveness of the proposed model, the various rolling conditions was tested.

• Coupled systems mechanics
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• 제11권1호
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• pp.43-54
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• 2022

In order to analyse the thermal performance of battery systems in electric vehicles complex simulation models with high computational cost are necessary. Using reduced order methods, real-time applicable model can be developed and used for on-board monitoring. In this work a data driven model of the cooling plate as part of the battery system is built and derived from a computational fluid dynamics (CFD) model. The aim of this paper is to create a meta model of the cooling plate that estimates the temperature at the boundary for different heat flow rates, mass flows and inlet temperatures of the cooling fluid. In order to do so, the cooling plate is simulated in a CFD software (ANSYS Fluent ®). A data driven model is built using the design of experiment (DOE) and various approximation methods in Optimus ®. The model can later be combined with a reduced model of the thermal battery system. The assumption and simplification introduced in this paper enable an accurate representation of the cooling plate with a real-time applicable model.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제13권2호
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• pp.109-122
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• 2009

This study investigates the change in two theoretical constructs, attitudes toward mathematics and mathematics self-efficacy, among college students involved in a learning community model. The case of this study was a developmental mathematics class offered at a historically black college located in the southeastern United States. Subjects included 31 students enrolled in an introductory mathematics course, some of whom participated in a learning community (treatment group). The participants completed mathematics attitudes and mathematics efficacy instruments twice: at the beginning of the semester and again at the end. Data was analyzed using descriptive statistics and a non-parametric statistic. The results showed that students' attitudes toward mathematics and mathematics self-efficacy are strongly correlated; the mathematical problem-solving efficacy changed significantly over time and it is significantly higher in the treatment group than in the control group; and the treatment group produced better outcomes. These findings indicate that a learning community model can increase students' mathematics self-efficacy beliefs. It is recommended that mathematics self-efficacy and attitudes toward mathematics be measured over an extended period of time when a learning community is implemented.

• 한국지능시스템학회논문지
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• 제14권2호
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• pp.195-200
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• 2004

컴퓨터 게임은 보이드들의 군집 행동 모델링을 위하여 플로킹이라는 지능적인 기법을 사용하고 있다. 플로킹은 약간의 컴퓨터 자원만을 이용하여 조류나 물고기와 같은 예측할 수 없는 형태의 군집 행동 패턴을 자연스럽게 모델링 할 수 있다. 단 논문에서 우리는 사실적인 수중 생태계 군집 행동 모델링을 위하여, 포식자 및 먹이로 구성되는 생태계를 구현하였다. 또한 퍼지 논리를 생태계 요소들의 본능적인 욕망을 구현하기 위하여 적용하였다 그 결과 본 모델은 생태계의 파괴를 극복하고, 자연스럽게 생태계 행동을 모델링 할 수 있다는 것을 확인하였다.

• Geomechanics and Engineering
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• 제11권5호
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• pp.691-711
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• 2016

In this study, the uplift capacity of anchor plates embedded in sand was investigated by conducting model tests. Square shaped anchors were used in the tests and parameters such as relative density of sand, embedment ratio (H/B), spacing ratio between anchors (S/B) and anchor configuration affecting the uplift capacity were investigated. Breakout factor and group efficiency which are dimensionless parameters were used to show the results. A series of finite element analyses and analytical solutions were additionally performed to ascertain the validity of the findings from the laboratory model tests and to supplement the results of the model tests. It can be concluded that the embedment depth in dense sand soil condition is the most important parameter with respect to the other parameters as to influencing the uplift capacity of group anchors.

• 한국태양에너지학회 논문집
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• 제28권4호
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• pp.56-61
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• 2008

The modeling of PV (Photovoltaic) module is useful to perform detailed analysis of PV system performance for changing meteorological conditions, verify actual rated power of PV system sizing and determine the optimal design of PV system and components. This paper indicates a modeling approach of PV module performance in terms of meteorological conditions and identifies validity of this modeling method by comparing measured with simulated value of various PV modules using simulation model.