• Steel and Composite Structures
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• v.50 no.4
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• pp.383-401
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• 2024

The research comprehensively studies the axial compression performance of T-shaped concrete-filled thin-walled steel tubular (CTST) long columns after fire exposure. Initially, a series of tests investigate the effects of heating time, load eccentricity, and stiffeners on the column's performance. Furthermore, Finite Element (FE) analysis is employed to establish temperature and mechanical field models for the T-shaped CTST long column with stiffeners after fire exposure, using carefully determined key parameters such as thermal parameters, constitutive relations, and contact models. In addition, a parametric analysis based on the numerical models is conducted to explore the effects of heating time, section diameter, material strength, and steel ratio on the axial compressive bearing capacity, bending bearing capacity under normal temperature, as well as residual bearing capacity after fire exposure. The results reveal that the maximum lateral deformation occurs near the middle of the span, with bending increasing as heating time and eccentricity rise. Despite a decrease in axial compressive load and bending capacity after fire exposure, the columns still exhibit desirable bearing capacity and deformability. Moreover, the obtained FE results align closely with experimental findings, validating the reliability of the developed numerical models. Additionally, this study proposes a simplified design method to calculate these mechanical property parameters, satisfying the ISO-834 standard. The relative errors between the proposed simplified formulas and FE models remain within 10%, indicating their capability to provide a theoretical reference for practical engineering applications.

• IMMUNE NETWORK
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• v.24 no.1
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• pp.9.1-9.21
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• 2024

The cytokine IL-7 plays critical and nonredundant roles in T cell immunity so that the abundance and availability of IL-7 act as key regulatory mechanisms in T cell immunity. Importantly, IL-7 is not produced by T cells themselves but primarily by non-lymphoid lineage stromal cells and epithelial cells that are limited in their numbers. Thus, T cells depend on cell extrinsic IL-7, and the amount of in vivo IL-7 is considered a major factor in maximizing and maintaining the number of T cells in peripheral tissues. Moreover, IL-7 provides metabolic cues and promotes the survival of both naïve and memory T cells. Thus, IL-7 is also essential for the functional fitness of T cells. In this regard, there has been an extensive effort trying to increase the protein abundance of IL-7 in vivo, with the aim to augment T cell immunity and harness T cell functions in anti-tumor responses. Such approaches started under experimental animal models, but they recently culminated into clinical studies, with striking effects in re-establishing T cell immunity in immunocompromised patients, as well as boosting anti-tumor effects. Depending on the design, glycosylation, and the structure of recombinantly engineered IL-7 proteins and their mimetics, recombinant IL-7 molecules have shown dramatic differences in their stability, efficacy, cellular effects, and overall immune functions. The current review is aimed to summarize the past and present efforts in the field that led to clinical trials, and to highlight the therapeutical significance of IL-7 biology as a master regulator of T cell immunity.

• Korean Journal of Adult Nursing
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• v.13 no.1
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• pp.15-28
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• 2001

The purpose of this study was to identify the trends of resourcefulness researche studies for suggesting the future direction of study. Study design, types of subjects, measurement tools, study concept, and outcome were examined by reviewing 61 research studies published from 1980 to 1999. The results were as follows: 1. There were 24 works in the 1980s and 37 works in 1990, according to the published year of resourcefulness study. Nonexperimental studies like descriptive study, correlational study and comparative study were more frequent than experimental studies. 2. Research studies that consisted of 30- 100 subjects were the most numerous with 27 studies in all. The majority of study subjects was shown as healthy students and depressive patients. 3. Most studies used Rosenbaum's Self Control Schedule(SCS) for assessing resourcefulness. Reliabilities of resourcefulness researches were cronbach ${\alpha}=.70$ or more. According to statisitical tests done for internal validity, SCS was negatively correlated to maladaptation. Factor analysis revealed that the most parsimonious structure was 3 to 6 factors. The total communality variance in the SCS was about 40 %. Other tools used with the SCS were about coping, depression, satisfaction of life and symptoms, self management and health promotion. 4. In correlational studies, concepts like depression, anxiety, and psychological symptoms were related to resourcefulness negatively. Adaptive functioning, life satisfaction and self achievement had positive correlations to resourcefulness. 5. Studies on comparison between a healthy person and depressive patient or smoker and non-smoker were done. There were coping, depression, symptom, self efficacy, health problem and self-control as comparative concepts. 6. Study subjects consisted of depressive patients in 9 of 18 experimental studies. The majority of studies were done with cognitive-behavioral therapy as an experimental intervention. The most effective treatment was revealed in high resourcefulness group. Since the above findings, resourcefulness research increased since 1980 and mostly non-experimental design for quantitative study were done. In the field of nursing, research about resourcefulness was in an initial stage. It is expected that further research needed to be done. Recommendations on the basis of the present research suggest that it is necessary to replicate studies, develop nursing intervention enhancing resourcefulness and apply it to patients with chronic diseases including cancer.

• Journal of vocational education research
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• v.29 no.3
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• pp.247-263
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• 2010

The purpose of this study is making the career education program related to the subject, Manual Training and Home Economics, to present the effective guidance and to improve career maturity of students about the unit, "Making a choice of career and Job ethics" of middle school senior's course. In order to estimate this program, 60 students of 2 classes were chosen as research subjects among middle school seniors and each of classes was divided into two groups, an experimental group and a control group. After the experimental group was trained the career education program related to Manual Training and Home Economics for 15 sessions, the effect was verified by comparing tests before and after program execution. In order to prove effects of the program. Each grade of both the experimental group and the control group was taken analysis of covariance (ANCOVA). Result of the program experiment is following. First, after executing the career education program related to Manual Training and Home Economics to the experimental group, participants showed that both attitude and ability for career maturity were improved in each sub-factor field of the career maturity as a result of tests before and after program execution. Second, in program satisfaction estimation, most of students had a positive attitude and in every time satisfaction, they made high estimation on the program, especially including the proper level of students and interesting activities. Finally, the final program was completed based on the result of effect analysis of the program.

• Journal of the Korean GEO-environmental Society
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• v.20 no.3
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• pp.21-30
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• 2019

Composite pile, which is composed of the steel pipe pile in which the large horizontal force acts and the PHC pile in which the small horizontal force acts by a special connecting devices, is being commercialized as a base material for civil engineering structures. The core of such a composite pile can be said to be a design criterion for estimating the joint position and stability of the connection device between steel pipe pile and PHC pile. In Korea, there is no precise specification for the location of composite pile joints. In the LH Design Department (Korea Land & Housing Corporation, 2009), "Application of composite pile design and review of design book marking" was made with reference to Road Design Practice Volume 3 (Korea Expressway Corporation, 2001). this is used as a basis of the design of the composite pile. It can not be regarded as a section change of the composite pile, so it has a limitation in application. Therefore, In this study, we propose a design criterion for the location of the section of the composite pile (joint of steel pipe pile and PHC pile) and evaluate the stability and economical efficiency of it by using experimental method and analytical method. Analysis of composite pile design data installed in 79 domestic bridges abutment showed that the stresses, bending moments, and displacements acting on the pile body and connection of the pile were analyzed. Through the redesign process, it was confirmed that the stresses generated in the connecting device occur within the allowable stress values of the connecting device and the PHC pile. In conclusion, the design proposal of composite pile joint location through empirical case study in this study is an improved design method considering both stability and economical efficiency in designing composite pile.

• Journal of the Korean Society of Safety
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• v.31 no.6
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• pp.45-51
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• 2016

The purpose of this study is to investigate the influence of train-induced end rotation of simple supported track girder on the performance of a direct fixation track system (DFTS) in Yeongjong grand bridge. In this study, the influences of deflection of a DFTS and track girder on dynamic rail-track girder interaction forces for the track girder ends currently employed in airport express lines were assessed by performing field tests using actual vehicles running along the service lines. Therefore, the dynamic displacement of rail and track girder and the fastener stress on the center and ends sections of DFTS were measured for two different trains (AREX and KTX) running in Yeongjong grand bridge. A three-dimensional finite element analysis (FEA) model using the time-history function based on the design wheel load was used to predict the train-induced track and track girder displacement, and the FEA and field test results were compared. The analytical results reproduced the experimental results well within about 3-7% difference in the values. Therefore, the FEA model of DFTS on track girder is considered to provide sufficiently reliable FEA results in the investigation of the behavior of DFTS. Using the analytical and experimental results, the influence of train-induced end rotation of simple supported track girder on the interaction behavior of rail and track girder installed on a simple supported track girder ends, i.e., upward displacement of rail-track girder and the fastener stress, was investigated. It was found that the train-induced end rotation effect of track girder was not significantly affected by the upward displacement of rails and the fastener stresses of track girder ends. Further, the interaction behavior of rail and track girder were similar to or less than that of the general railway bridge deck ends, nevertheless the vertical displacement of track was higher than that of conventional DFTS on the general railway bridge. From the results, the dynamic responses of the DFTS on track girder ends were not significantly affected by the safety and stability of DFTS ends.

• Water for future
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• v.29 no.2
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• pp.249-260
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• 1996

There have been easily found a number of examples that misleading or unreasonable measuring data set of physical variables are often produced in the field and the laboratory. The primary reason is that the specific requirements of civil engineers are initially disregarded in designing the experimental apparatus. It results from a lack of mutual understanding and co-operating between the user group and the maker. Therefore, their fundamental knowledge and apprehension become indispensible in order to obtain measuring data with high confidence and good quality In this study it is shortly explained the basic structure and the operation system of the experimental equipments commonly used at the present. A simple measuring set is developed which is quite easy for a general civil engineer to design and operate without any other specialty of mostly electricity electronics. Based upon this requirement, one of data logger named PPDL8 is newly designed by making use of the parallel port in the personal computer, consisting of multi-channels able to measure 8 different point values simultaneously. It can also use many valuable sub-programs existing in PC because the user makes his own programs necessary for measurement, by himself. Of all things, it has a great advantage to increase the applicability of field measurements much larger when adopting the notebook computer to operate with small battery only. In addition this study gives, in fact, the excellent agreements of in-situ field variables by showing their measuring results of temperature, distance and turbidity.

• Journal of the Korea Concrete Institute
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• v.19 no.4
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• pp.401-409
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• 2007

The objective of this research is to provide better knowledge on the behavior of strong axis SRC column-RC beam joint, supported by experimental results, that can be broadly applicable to many structures. For this purpose, firstly literature reviews and field survey were made to classify the most commonly used for these types of joints. Then, experimental program was designed and performed including 6 SRC column-RC beam joint specimens designed with various joint details. Using the experimental results obtained from the quasi-static cyclic tests, structural performances of the joints such as hysteretic curves, maximum strength capacities, strength degradation beyond the maximum strength, ductilities, and energy dissipation capacities were investigated. Test results showed that specimens with wide beam shape (RCW-P, RCW-W, RCW-F) and T beam shape (RCT-W) showed better structural performances than the bracket type specimens (HBR-L, HBR-S). These specimens also revealed to have higher strength capacities than the nominal design strength. However, H beam bracket type specimens (HBR-L, HBR-S) need further study both analytically and experimentally to verify the reason for unexpected structural performances.

• The Journal of the Korea Contents Association
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• v.21 no.11
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• pp.793-805
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• 2021

The purpose of this study was to identify changes and differences in perceptions of disabilities, attitudes toward inclusive education, and teacher efficacy in Early childhood pre-service teachers through capstone design-based disability teaching material production classes. The study participants were 50 third-year child care majoring students (25 experimental group, 25 comparison group) who participated in capstone design class for one semester in 2020 at 3-year K university. Looking at the results of the study, the experimental group, which produced teaching materials for the disabilities, showed significant changes in disability awareness, attitude toward inclusive education, and teacher efficacy than the comparative group. there was a positive change in the perception of disability due to an increase in the overall understanding and knowledge of the disabilities. It is judged that these positive changes in the perception of people with disabilities gave positive changes to the attitude toward inclusive education and teachers' efficacy. This positive change of early childhood pre-service teachers will serve as an opportunity to improve the quality of teaching behavior and various roles of teachers when interacting with children with disabilities in the inclusive education field.

• Journal of the Korean Geosynthetics Society
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• v.9 no.4
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• pp.75-84
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• 2010

In this study, the long-term performance tests, which have extensibility, creep deformation, installation resistance and durability characteristic, is conducted to apply geosynthetic strip in field. The strength reduction factors using the test results are evaluated in order to calculate long-term design tensile strength. First, the creep deformation was evaluated by both the stepped isothermal method(SIM) and the time-temperature superposition(TTS) method. The creep reduction factor is reasonable to apply 1.6. Second, the result of installation damage test had little damage of yarn, which affected strength of reinforcement. Therefore, it can be analyzed that the installation damage of geosynthetic strip has little effect of long-term design tensile strength. Finally, the durability reduction factor considering chemical, biological and outdoor exposure resistance is reasonable to apply 1.1, which is considered the stability and economic efficiency of reinforced earth wall using geosynthetic strip.