• Journal of the Earthquake Engineering Society of Korea
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• v.16 no.1
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• pp.1-12
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• 2012

In this paper, the reduction factors to calculate the site coefficients of an embedded foundation are estimated, considering the effect of a poor backfill for the seismic design of a building built on an embedded foundation. This is determined by utilizing in-house finite element software, P3DASS, which has the capability of horizontal pseudo 3D seismic analysis with nonlinear soil. The 30m thick soil on stiff rock was assumed to be homogeneous, elastic, viscous and isotropic, and equivalent circular rigid foundations with radii of 10-70m were assumed to be embedded 0, 10, 20, and 30 m in the soil. Seismic analyses were performed with 7 bedrock earthquake records de-convoluted from the outcrop records; the scaling of the peak ground accelerations were to 0.1 g. The study results show that the site coefficients of a poor-backfilled foundation are gradually reduced as the foundation embedment ratio increases, except in the case of a small foundation embedded deeply in the weak soft soil. In addition, it was found that the deviation of the site coefficients due to the foundation size was not significant. Therefore, the typical reduction factors of an embedded foundation with poor backfill are proposed in terms of the shear wave velocity and site class. This is in order to find the site coefficients of an embedded foundation by multiplying the reduction factor by a site coefficient of a surface foundation specified in the design code. They can then be interpolated to determine the intermediate shear wave velocity.

• Journal of the Korean Home Economics Association
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• v.25 no.3
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• pp.63-82
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• 1987

This is the forth consecutive study on the 'Standardization of Measurement for Korean Kitchen Work Centers and Cabinets for Future Design Criteria'. The purpose of the present research was (1) to classify homemakers' representative like styles related to the kitchen, (2) to examine homemakers' present concerns on the kitchen space, and (3) to investigate homemakers' desire and preference on the kitchen space. Twenty two hundred homemakers of upper and middle class residing in Seoul, Busan, Daegu, Incheon, Gwangju and Daejeon were selected for the survey and 1,843 among them were used for data analysis. Data were selected for the survey and 1,843 among them were used for data analysis. Data were analyzed using the SAS program package. The statistics used were frequency, percentage, mean, factor analysis, F-test, Duncan's multiple range test, X2-test, cluster analysis. Findings from the research as follows: (1) Four factors were found as indicaters of the life style; values on the household work, desire on social function of the kitchen, degree on cooperation of family members on the household work, and convenient management. It was noticeable that homemakers had positive responses in terms of desire on social function of the kitchen and degree on cooperation of family members on the household work. Homemakers' life styles related to the kitchen space were classified into 6 categories. (2) Relatively a few respondents answered that the kitchens were very well furnished. If, however, the economic conditions become better, substantial number of them wanted to invest for better kitchen following the one for living room. (3) It was found that most respondents preferred the arrangement of space, where dining and kitchen in one space, and a hard wall or soft treatment was between living and dining/kitchen area. (4) Many respondents desired pantry, utility and laundry area be near the kitchen or in the same space with it, thereby forming a utility core in a housing space.

• Korean Journal of Construction Engineering and Management
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• v.6 no.4 s.26
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• pp.101-112
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• 2005

Recently, a curtain wall construction is a exterior finishing components which is most used for shortening time in high-rise building as well as the class of key management factors in cost and schedule control. Also, it is recognized that an effective management for curtain wall process is a major subject to accomplish the project successfully. However, as the current management for curtain wall construction is focused on the construction stage, it makes problems such as errors in business performance, rework by mistakes and duplications, errors and omissions by ineffective information management and there has never been any efficient management from a view of the entire Curtain Wall Life-cycle process. Therefore, the aim of this study is to suggest a stage check point for process improvement in the curtain wall Life-cycle process through current curtain wall process analysis, and then to investigate the cause of waste factors using the Muda method from the Toyota Production System and extract the weighted effects of the waste factors using the analytical hierarchy process method. According to the result, Most of the inefficient factors happened in architectural design stage of the entire curtain wall Life-cycle process and my research identified that detail factors of them are a delay of decision making and an approval in changes, a deficit of engineering capacity and a delay of approval in architectural design drawings by owner, etc.

• The Journal of Sustainable Design and Educational Environment Research
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• v.19 no.3
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• pp.38-47
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• 2020

This study analyzed the perceptions of teachers to establish the direction for managing the space outside an elementary school. Satisfaction with outdoor school spaces is influenced by the satisfaction with tree and flower plantation and outdoor rest spaces. This study found that the longer the working years of a teacher, the higher their awareness of the importance and necessity of outdoor spaces in the school. Respondents emphasized the lack of manpower and budget, as well as the indifference of the administration as hindrances to the management of outdoor spaces in the school. The outdoor space in the school should include a secure play area, plant education space, class practice spaces, and a rest area. Furthermore, the space outside the elementary school should support learning, playing, and resting. To this end, facilities such as benches, pergolas, outdoor classrooms, ecological ponds, farms, and flower beds should be provided. In an outdoor space, plants featured in textbooks, seasonal plants, and those that provide shade can be planted along with labels to provide information and thereby promote learning. The teachers expected that the management of the external space will have an educational and emotional effect on students. In response to the innovation of the school spaces, it is necessary to continuously manage the external spaces to achieve educational and emotional effects by organically connecting the outdoor spaces with the indoor space. For this purpose, it is required to provide support for securing budgets and manpower, and to introduce relevant policies.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.5
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• pp.321-328
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• 2015

In recent years, there has been an increasing demand to apply the new IACS(International Association of Classification Societies) standards for ice and polar-classed ships. For ice-class vessel propulsion system, the ice impact torque design criterion is defined as a periodic harmonic function in relation to the number of the propeller blades. However, irregular or transient ice impact torque is assumed to occur likely in actual circumstances rather than these periodic loadings. In this paper, the reliability and torsional vibration characteristics of a comparatively large six-cylinder marine diesel engine for propulsion shafting system was examined and reviewed in accordance with current regulations. In this particular, the transient ice impact torque and excessive vibratory torque originating from diesel engine were interpreted and the resonant points identified through theoretical analysis. Several floating ice impacts were carried out to evaluate torque responses using the calculation method of classification rule requirement. The Newmark method was used for the transient response analysis of the whole system.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.6
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• pp.85-96
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• 2000

It is necessary that fully differential operational amplifier circuit should drive an external load in the VLSI design such as SCF(Switched Capacitor Filter), D/A Converter, A/D Converter, Telecommunication Circuit and etc. The conventional CMOS operational amplifier circuit has many problems according to CMOS technique. Firstly, Capacity of large loads are not able to operate well. The problem can be solve to use class AB stages. But large loads are operate a difficult, because an element of existing CMOS has a quadratic functional relation with input and output voltage versus output current. Secondly, Whole circuit of dynamic range decrease, because a range of input and output voltages go down according as increasing of intergration rate drop supply voltage. The problem can be improved by employing fully differential operational amplifier using differential output stage with wide output swing. In this paper, we proposed new current mirror has large output impedance and good current matching with input an output current and compared with characteristics for operational amplifier using cascoded current mirror. To obtain large output swing and low power consumption we suggest a fully differential operational amplifier. The circuit employs an output stage composed new current mirror and two amplifier stage. The proposed circuit is layout and circuit of capability is inspected through simulation program(SPICE3f).

• 대한공업교육학회지
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• v.38 no.2
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• pp.195-217
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• 2013

The purpose of this study was to develop educational programs of STEAM-based project under the theme of "Photography of Earth" for the circle activities of the creative experiential activity, to be applied this program to them and to identify technology subject self-efficacy and change in attitude toward engineering. In order to achieve the research objectives, this program was applied to middle school student in Cheonan, STEAM-based circle during 9 class instruction. The results of this study are as follows. First, the STEAM program contents for circle activities were selected through utilizing a five-stage design model(preparation, design, development, implementation and evaluation) and analyzing the curriculum. After that we have developed a teaching plan, STEAM-Story, student activity sheets from the viewpoint of cultural fusion and have applied the circle activities of the creative experiential Activity during 4 months. Second, The result of the test(pre- and post-test) about STEAM program that has been developed were different about technology subject self-efficacy and attitude toward engineering. Therefore, we have verified that the effect of the STEAM-based project under the theme of "Photography of Earth" for the circle activities on the attitudes toward engineering and self-efficacy in middle school is effective.

• Journal of the Korean Applied Science and Technology
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• v.37 no.5
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• pp.1366-1377
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• 2020

The purpose of this study was to confirm the effect of the Havruta-based teaching and learning method on the academic self-efficacy, critical thinking tendency, learning satisfaction, and academic stress of nursing students. This study was conducted with 90 2nd graders of nursing department with one-group pretest-posttest design. The Havruta-based instructional design consists of five stages: the 1 stage is the pre-learning stage, the 2 stage is the introduction and development stage, the 3 stage is the organization of the class content, the 4 stage is the question and teaching stage, and the 5 stage is organized and integrated. Four weeks of Havruta-based teaching and learning method was applied. The data were analyzed by SPSS 25.0. The general characteristics of the subjects were frequency and percentage, and The dependent variable for measuring the effect of experimental treatment was analyzed by paired t-test. As a result of the study, the application of the Havruta-based teaching and learning method showed statistically significant results on academic self-efficacy(t=-3.711, p<.000), learning satisfaction(t=-2.580, p=.012), and academic stress(t=6.500, p<.000). The Havruta-based teaching and learning method has been confirmed to be an effective teaching method that increases the subject's academic self-efficacy, learning satisfaction, and lowers academic stress, so it can be applied to other major subjects in the future.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.3
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• pp.209-215
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• 2017

A large floating offshore wind-wave hybrid power generation system with an area of 150 m2 and four 3 MW class wind turbine generators was installed at each column top. In accordance with the wind turbine arrangement, the wake generated from upstream turbines can adversely affect the power performance and load characteristics of downstream turbines. Therefore, an optimal arrangement design, obtained through a detailed flow analysis focusing on wake interference, is necessary. In this study, to determine the power characteristics and annual energy production (AEP) of individual wind turbines, transient computational fluid dynamics, considering wind velocity variation (8 m/s, 11.7 m/s, 19 m/s, and 25 m/s), was conducted under different platform conditions ($0^{\circ}$, $22.5^{\circ}$, and $45^{\circ}$). The AEP was calculated using a Rayleigh distribution, depending on the wind turbine arrangement. In addition, we suggested an optimal arrangement design to minimize wake losses, based on the AEP.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.564-568
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• 2020

Problem-based learning (PBL) is applied to various subjects for the sake of learners' creative thinking, problem-solving skills, presentation skills, confidence, self-directed learning, cooperation, and for the communication skills required in a rapidly changing society. Among them, the English language-an official language-is invested in 2.3 times more than other subjects, according to the English education company Yoon's Teacher. Therefore, PBL is an important learning method. However, the reality is that teacher-centered instruction, acquiring knowledge of the best answers only, and traditional evaluations are the main subjects. In order to supplement these weak points, this study designed a learning model for English subjects based on Barrows & Myers (2002) and the analyze, design, develop, implement, and evaluate (ADDIE) model. As a result of a PBL English class based on the ADDIE model, the learners were able to improve their presentation skills by 86%, their interest in learning by 86%, their understanding of learning by 86%, and cooperation by 100%. As such, studies on designing the learning model should be carried out continuously to achieve the purpose of 21st century English education, which is to improve learners' communication skills and information processing skills.