• Structural Engineering and Mechanics
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• 제87권2호
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• pp.151-164
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• 2023

The latest earthquake's costly repairs and economic disruption were brought on by excessive residual drift. Self-centering systems are one of the most efficient ways in the current generation of seismic resistance system to get rid of and reduce residual drift. The mechanics and behavior of the self-centering system in response to seismic forces were impacted by a number of important factors. The amount of post-tensioning (PT) force, which is often employed for the standing posture after an earthquake, is the first important component. The energy dissipater element is another one that has a significant impact on how the self-centering system behaves. Using the damper as a replaceable and affordable tool and fuse in self-centering frames has been recommended to boost energy absorption and dampening of structural systems during earthquakes. In this research, the self-centering steel moment frame connections are equipped with cushion flexural dampers (CFDs) as an energy dissipator system to increase energy absorption, post-yielding stiffness, and ease replacement after an earthquake. Also, it has been carefully considered how to reduce permanent deformations in the self-centering steel moment frames exposed to seismic loads while maintaining adequate stiffness, strength, and ductility. After confirming the FE model's findings with an earlier experimental PT connection, the behavior of the self-centering connection using CFD has been surveyed in this study. The FE modeling takes into account strands preloading as well as geometric and material nonlinearities. In addition to contact and sliding phenomena, gap opening and closing actions are included in the models. According to the findings, self-centering moment-resisting frames (SF-MRF) combined with CFD enhance post-yielding stiffness and energy absorption with the least amount of permeant deformation in a certain CFD thickness. The obtained findings demonstrate that the effective energy dissipation ratio (β), is increased to 0.25% while also lowering the residual drift to less than 0.5%. Also, this enhancement in the self-centering connection with CFD's seismic performance was attained with a respectable moment capacity to beam plastic moment capacity ratio.

• 한국정보시스템학회지:정보시스템연구
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• 제5권
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• pp.345-371
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• 1996

Previous studies on user training have largely focused on assessing models which describe the determinants of information technology usage or examined the effects of training on user satisfaction, productivity, performance, and so on. Scant research efforts have been made, however, to examine those effects of training by using theoretical models. This study presented a conceptual models to predict intention to use information technology and conducted an experiment to understand how training for computer skill acquisition affects primary variables of the model. The data were obtained from 32 student subjects of an experimental group and 31 students of a control group, and the information technology employed for this study was a university electronic mail system. The study results revealed that attitude toward usage and perceived behavioral control helped to predict user intentions ;; outcome expectations were positively related to attitude toward usage ; and self-efficacy was positively related to perceived behavioral control. The hands-on training for the experimental group led to increases in perceived ease of use, self-efficacy and perceived behavioral control. The changes in those variables suggest more causal effects of user training than other survey studies.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.307-313
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• 2002

In the paper, the prototype development of a 75kW class microturbine for the distributed generation market is partly presented which has continued with the government funding. In the introduction, an overview of the development of microturbines in the world is presented. A series of development procedures are shown with design, manufacture and self-sustaining tests. During the first year, aerodynamic and structural design/analysis, mechanical design are performed for the compressor, the turbine and the combustor. A premixed lean burn combustor technology is used fur the low emission requirements. Foil air bearings and high-speed motors are employed for higher reliability. The self-sustaining conditions have been successfully achieved with the prototype manufactured engine as a preceding operation.

• 한국IT서비스학회지
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• 제19권1호
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• pp.159-172
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• 2020

The purpose of this study is to examine the structural relationship among factors affecting learning engagement, satisfaction, continuance intention in China-MOOC. For this study, data were collected from 334 students who were taking MOOC classes. and structural equation model ling analyses were employed to examine the causal relationships among variables. From the results of this study, First, self-regulated learning and interaction significantly affected learning engagement. Second, interaction had direct effects on satisfaction. Third, satisfaction significantly affect continuance intention. Furthermore, satisfaction mediated relationships between interaction and continuance intention. These results imply that self-regulated learning, interaction, learning engagement should be considered for designing and implementing China-MOOC learning. Further implication are discussed in the study.

• 한국건축시공학회지
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• 제12권6호
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• pp.664-673
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• 2012

Determining the layout of temporary facilities that support construction activities at a site is an important planning activity, as layout can significantly affect cost, quality of work, safety, and other aspects of the project. The construction site layout problem involves difficult combinatorial optimization. Recently, various artificial intelligence(AI)-based algorithms have been applied to solving many complex optimization problems, including neural networks(NN), genetic algorithms(GA), and swarm intelligence(SI) which relates to the collective behavior of social systems such as honey bees and birds. This study proposes a site facility layout optimization algorithm based on self-organizing maps(SOM). Computational experiments are carried out to justify the efficiency of the proposed method and compare it with particle swarm optimization(PSO). The results show that the proposed algorithm can be efficiently employed to solve the problem of site layout.

• 대한간호학회지
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• 제38권4호
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• pp.513-521
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• 2008

Purpose: The purpose of this study was to develop an integrated suicide violence prevention program for adolescents. Another purpose was to evaluate the effects of the integrated suicide violence prevention program on self-esteem, parent-child communication, aggression, and suicidal ideation in adolescents. Methods: The study employed a quasi -experimental design. Participants for the study were high school students, 24 in the experimental group and 25 in the control group. Data was analyzed by using the SPSS/WIN. 11.5 program with $X^2$ test, t-test, and 2-way ANOVA. Results: Participants in the integrated suicide violence prevention program reported increased self-esteem scores, which was significantly different from those in the control group. Participants in the integrated suicide violence prevention program reported decreased aggression and suicidal ideation scores, which was significantly different from those in the control group. Conclusion: The integrated suicide violence prevention program was effective in improving self-esteem and decreasing aggression and suicidal ideation for adolescents. Therefore, this approach is recommended as the integrated suicide violence prevention strategy for adolescents.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.238-242
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• 1991

This paper presents an approach to self-tuning PI control of dynamic plants, based on fuzzy logic application. A fuzzy logic composed of linguistic conditional statements is employed by defining the relations of input-output variables of the controller. In the synthesis of a fuzzy logic controller, one of the most difficult problem is the selection of linguistic control rules and parameters. To overcome this difficulty, self-tuning fuzzy PI controller (STFPIC) with a hierarchical structure in which the fuzzy PI controller is assigned as the lower level and the rule modification and parameter adjustment as the higher level. The rules and parameters are generated by the adjustment of membership function through performance index(PE). In this paper, the algorithm for of the controller performance is estimated by means of computer simulation.

• 대한가정학회지
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• 제44권4호
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• pp.11-21
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• 2006

The purpose of this study was to identify the ecological variables related with children's emotional intelligence, examine their recognition of all the variables affecting their emotional intelligence and classify the variables into the categories of children (gender, grade, self-efficacy), home environment (employed mother or unemployed mother, communication between parents and child, type of family composition, number of siblings), and peer group environment (peer group). The study subjects were 680 elementary school students. Data were analyzed via t-test, F-test, correlation, and multiple regression. The results of this study were as follows. First, emotional intelligence showed significant difference and relationship among the children variables, home environment variables, and peer group environment variable. (Ed- also note the absence of 'fourth' above) Second, emotional intelligence in children was relatively reviewed by the above three variables and the most affecting variable was self-efficacy in children.

• 전자공학회논문지D
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• 제35D권7호
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• pp.88-93
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• 1998

For the self-aligned AlGaAs/GaAs HBTs, the surface states at the interface between the extrinsic base surface and the passivation nitride is a major cause of degradation of dc characteristics. In this paper the degradation mechanisms of self-aligned AlGaAs/GaAs HBT were analyzed, and GaAs HBTs, which employed an InGaP ledge emitter structure formed by the nonself-aligned process to cover the surface of the extrinsic base and reduce the surface states, produced high reliability. Accoridng to the acceleration lifetime test, the nonself-aligned InGaP/GaAs HBTs produced very reliable dc characteristics comparing with the self-aligned AlGaAs/GaAs HBTs. The activation energy was 1.97eV and MTTF $4.8{\times}10^{8}$ hrs at $140^{\circ}C$ which satisfied the MIL standard.

• 대한가정학회지
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• 제35권3호
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• pp.151-169
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• 1997

The purpose of this study was to analyze contributing factors to elder's life problem and their life planning. The sample in this study consisted of 556 elderly husband and wives over 55 years old loving in Seoul, Daejeon, Jeonju and Daegu. Statistics employed for the analysis were frequencies, means, and multiple regression analysis. The results could be summarized as follows. Elderly's life problem and planning were negatively related in economic and leisure domain. And family relationship and self-esteem had significant effects on the perception of life problem, while hoe ownership, total income and total asset had not effect on perception of life problem of elderly. Also, family relationship, self-esteem and locus of control had effect on life planning of elderly. These findings pointed that psychological variables as family relationship and self-esteem play a more important role than economic variables in life of elderly.