• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.04a
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• pp.61-68
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• 1993

A computer program for free vibration analysis of plane framed structures has been developed by object oriented programming technique using C" language. The object oriented programming concepts such as object, class, method and inheritance are represented. The static and free vibration analyses for framed structures were satisfactorily performed by this program which consists of TOP, VECTOR, MATRIX, STRU, GUI and other classes. Numerical test shows the validity and capability of the present study which can be expandable to develop a general purpose object oriented finite element analysis program of structures ,res ,

• 연구논문집
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• s.33
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• pp.53-65
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• 2003

Electrostatic micro-motors can be divided into three classes: (i) salient type side drive motor, (ii) radial gap type wobble motor, (iii) axial gap type wobble motor. The working mechanism, torque evaluation, fabrication, and operational characteristics of each micro motors are compared. It is proved that axial gap type wobble motor has the bigger generating torque than that of the other type. The gear ratio of wobble motors increases the driving torque at the cost of a decreasing angular speed and decreases the friction because of the rolling motion instead of sliding at the bearing. Techniques for characterizing micro-motors performance are presented.

• Steel and Composite Structures
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• v.7 no.3
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• pp.185-200
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• 2007

Tubular construction is widely used in a range of civil and structural engineering applications. To date, the principal product range has comprised square, rectangular and circular hollow sections. However, hot-rolled structural steel elliptical hollow sections have been recently introduced and offer further choice to engineers and architects. Currently though, a lack of fundamental structural performance data and verified structural design guidance is inhibiting uptake. Of fundamental importance to structural metallic design is the concept of cross-section classification. This paper proposes slenderness parameters and a system of cross-section classification limits for elliptical hollow sections, developed on the basis of laboratory tests and numerical simulations. Four classes of cross-sections, namely Class 1 to 4 have been defined with limiting slenderness values. For the special case of elliptical hollow sections with an aspect ratio of unity, consistency with the slenderness limits for circular hollow sections in Eurocode 3 has been achieved. The proposed system of cross-section classification underpins the development of further design guidance for elliptical hollow sections.

• Journal of Internet Computing and Services
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• v.9 no.5
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• pp.85-97
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• 2008

Recently, service-oriented systems have been issued by their properties of reducing software development time and effort by reusing functional service units. The reusability of services can effectively promote through loose coupling between services and loose coupling between services depends on component-based system. That is, the component-based system is designed by grouping the tightly coupled classes of the object-oriented system and the service-oriented system is designed by the component-based system. Therefore, to design the component-based system and service-oriented system efficiently, a metric to measure the coupling between classes accurately needs. In this paper, we propose a coupling metric between classes applying a structural property, a dynamic property, and the normalized value by 0-1. We prove the theoretical soundness of the proposed metric by the axioms of briand et al, and suggest the accuracy and practicality through a case study. We suggest the evaluation results of the proposed metric through a comparison with the conventional metrics.

• Journal of The Korean Association For Science Education
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• v.38 no.1
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• pp.69-85
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• 2018

The purpose of this study is to explore teachers' responsive moves that affect students' argumentation practices, and to propose responsive teaching strategies in argumentation-based science classroom. Two teachers, who have not implemented argumentation in their classes, and 57 students, participated in this study. We recorded and transcribed their classes and interviews for the analysis. According to grounded theory approach, we categorized the teachers' responsive moves as focused on either structural or dialogical aspects of argumentation, and qualitatively analyzed their responsive teaching practices in classes. We discovered that the teachers mostly responded to structural rather than dialogical aspects of argumentation, particularly during the students' small-group discussions. This was mainly due to their instructional goals, which focused on the structural aspect of argumentation, and the limited time available for supporting small-groups. Regarding the structural aspects, those responsive moves that explored the students' thinking or facilitated their reasoning helped them to share their thinking and justify their arguments further with recognition of learning goals in the argumentation activities. Regarding the dialogical aspects, which were seen mostly in whole-class discussions, the moves that underlined similarities and differences between arguments, facilitated the sharing of a small-group's arguments with the entire class, or asked a specific student to evaluate the arguments were notable. These moves supported clarification of various small-groups' arguments, which led to reconstruction of coherent argument through evaluation and rebuttal of these arguments, consequentially facilitating dialogical interactions. Based on these results, we proposed responsive teaching strategies in an argumentation-based science classroom.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2007.04a
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• pp.219-222
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• 2007

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2679-2683
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• 2011

The purpose of this study is to develop automated structural design and analysis aided-program of aluminum extrusion carbody structures for railway vehicle. This developed program is possible to perform simultaneously structural design and design verification of aluminum extrusion profiles independent of expertise and experience of design engineers. Design engineers was able to design it using database of existing aluminum extrusion profiles or user-defined function. The design verification was programmed to evaluate its structural integrity according to Korean Railway Safety Law or Urban Transit Safety Law. Also, this program could automatically generate an executable file of various commercial finite element program and CAD files such as stp and iges by GUI environment applications using MFC(Microsoft Foundation Classes). In conclusion, it is expected to contribute to reduce product development time and improve product quality of aluminum extrusion profile and structures in railway industry.

• Korean Journal of Human Ecology
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• v.19 no.1
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• pp.63-74
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• 2010

The purpose of the study was to examine the actual conditions of caregiver-infant ratios, group-room activity areas, evaluations of infant programs and caregiver-infant interactions based on structural and process indicators which are major factors of infant care. The subjects were 20 caregivers and 91 infants from 14 infant classes of 13 day care centers in Daejeon. An actual survey was conducted on caregiver-infant ratios and group-room activity areas, and teaching-learning plans for infants and daily schedules were gathered for the evaluation of infant programs. The caregiver-infant interactions were observed every one minute for a total of 20 minutes using Lee Wan Jeong's "Evaluation Measure of Caregiver-infant Interactions"(1999). The results of this study were as follows: First, caregiver-infant ratios ranged from 2.5 to 7 infants per caregiver, resulting in the difference of the number of infants. Second, the 14 classes for one-year-old infants were arranged in three different ways; 5 classrooms with distinctive activity areas, 2 without any divided areas and 7 containing a mix of partial activity areas. Third, in teaching-learning plans for infants, there were a large number of topics related to seasonal features and experiences while the fewest were about basic life habits. Fourth, in the caregiver-infant interactions, caregivers used more positive interactions and linguistic modeling than sensitive responses to infants and social interactions.

• Structural Engineering and Mechanics
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• v.60 no.6
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• pp.953-977
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• 2016

Modern performance-based design methods require ways to determine the factual behavior of structures subjected to earthquakes. Drift ratio demands are important measures of structural and/or nonstructural damage of the structures in performance-based design. In this study, global drift ratio and interstory drift ratio demands, obtained by nonlinear time history analysis of three generic RC frames using code-compatible ground motion record sets, are statistically evaluated. Several ground motion record sets compatible with elastic design spectra defined for the local soil classes in Turkish Earthquake Code are used for the analyses. Variation of the drift ratio demands obtained from ground motion records in the sets and difference between the mean of drift ratio demands calculated for ground motion sets are evaluated. The results of the study indicate that i) variation of maximum drift ratio demands in the sets were high; ii) different drift ratio demands are calculated using different ground motion record sets although they are compatible with the same design spectra; iii) the effect of variability due to random causes on the total variability of drift ratio demands is much larger than the effect of variability due to differences between the mean of ground motion record sets; iv) global and interstory drift ratio demands obtained for different ground motion record sets can be accepted as simply random samples of the same population at %95 confidence level. The results are valid for all the generic frames and local soil classes considered in this study.

• Geomechanics and Engineering
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• v.37 no.6
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• pp.565-576
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• 2024

In this study, the earthquake risk assessment of single-story RC precast buildings in Turkey was carried out using loss curves. In this regard, Kocaeli, a seismically active city in the Marmara region, and this building class, which is preferred intensively, were considered. Quality and period parameters were defined based on structural and geometric properties. Depending on these parameters, nine main sub-classes were defined to represent the building stock in the region. First, considering the mean fragility curves and four different central damage ratio models, vulnerability curves for each sub-class were computed as a function of spectral acceleration. Then, probabilistic seismic hazard analyses were performed for stiff and soft soil conditions for different earthquake probabilities of exceedance in 50 years. In the last step, 90 loss curves were derived based on vulnerability and hazard results. Within the scope of the study, the comparative parametric evaluations for three different earthquake intensity levels showed that the structural damage ratio values for nine sub-classes changed significantly. In addition, the quality parameter was found to be more effective on a structure's damage state than the period parameter. It is evident that since loss curves allow direct loss ratio calculation for any hazard level without needing seismic hazard and damage analysis, they are considered essential tools in rapid earthquake risk estimation and mitigation initiatives.