• Korean Journal of Childcare and Education
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• v.16 no.5
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• pp.105-126
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• 2020

Objective: This study aimed to reveal pre-service early childhood teachers' perception of children's environmental education using concept mapping and demonstrating its importance. Methods: Based on Kane and Trochim's(2007) procedure, 33 pre-service early childhood teachers conducted brainstorming and statement writing, and then the importance of selected statements were rated by 202 pre-service early childhood teachers. Selected statements were analyzed through multidimensional scaling and hierarchical cluster analysis. Results: Pre-service early childhood teachers perceived children's environmental education as concept mapping with 2-dimensions and eight clusters. The following eight clusters were established (1) daily practice through hands on experience, (2) nature environment, (3) recognizing and coping with environmental issues, (4) environmental preservation practices, (5) environmental sensitivity and consideration, (6) purpose of children's environmental education, (7) necessity for children's environmental education (8) Practice through connection with child's home and community. And then among the eight clusters, the most important was recognized as 'daily practice through hands on experience', and among the statements 'young children learn through the method of playing in nature and experience nature' was considered the most important. Conclusion/Implications: Based on these results, we discuss the importance of children's environmental education of pre-service early childhood teachers and how to support to develop teacher's training program.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.4
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• pp.547-554
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• 2002

We are facing the serious environmental pollution difficulties such as acid rain, green house effects, etc. The gaseous matter NOx, SOx, VOCs which are regarded as main factors for these current pollutions are mainly emitted from power plants and vehicles. Therefore several leading countries are regulating the emissions strictly, especially the exhaust emissions from a Diesel engine without an aftertreatment device. The objective of this study is to find out soot and NO removal characteristics focused on the emissions of a Diesel engine by using nonthermal plasma for each engine speeds and loads. Electrostatic precipitator(wire-to-plate type reactor) is used for soot removal. Radicals generated from outer air and put into a mixing chamber in the end of exhaust line are used for NO removal. Concentration of exhaust emissions is analyzed from the gas analyzer(KaneMay) and FTIR to estimate by-products.

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.265-271
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• 2005

Randomness exists in engineering. Tolerance, assemble-error, environment temperature and wear make the parameters of a mechanical system uncertain. So the behavior or response of the mechanical system is uncertain. In this paper, the uncertain parameters are treated as random variables. So if the probability distribution of a random parameter is known, the simulation of mechanical multibody dynamics can be made by Monte-Carlo method. Thus multibody dynamics simulation results can be obtained in statistics. A new concept called functional reliability is put forward in this paper, which can be defined as the probability of the dynamic parameters(such as position, orientation, velocity, acceleration etc.) of the key parts of a mechanical multibody system belong to their tolerance values. A flexible mechanical arm with random parameters is studied in this paper. The length, width, thickness and density of the flexible arm are treated as random variables and Gaussian distribution is used with given mean and variance. Computer code is developed based on the dynamic model and Monte-Carlo method to simulate the dynamic behavior of the flexible arm. At the same time the end effector's locating reliability is calculated with circular tolerance area. The theory and method presented in this paper are applicable on the dynamics modeling of general multibody systems.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.4
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• pp.458-468
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• 2016

Electromechanical model for analyzing a multimodal piezoelectric energy harvester comprising three connected beams is presented in this paper. This system consists of three beams which are connected alternately. The piezoelectric layer is only attached to the middle beam. With this special structural configuration, the first, second, and third natural frequencies are congregated so that the energy harvester can generate meaningful amount of power consistently when the main frequency component of the excitation varies around the lowest three natural frequencies of the harvester. To investigate the dynamic and electric response of the piezoelectric energy harvester, an electromechanical model is developed using the Kane's method and the accuracy of the model is validated by comparing the results obtained with the model with those obtained with the commercial software ANSYS. The results show that the piezoelectric energy harvester comprising three connected beams has much broader power generating frequency range than that of the conventional piezoelectric energy harvester.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.285-287
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• 2014

Equations of motion for the vibration analysis of rotating pre-twisted beams with functionally graded material properties are derived in this paper. Based on Timoshenko beam theory, the effects of shear and rotary inertia are considered. The pre-twisted beam has a rectangular cross-section and is mounted on a rotating rigid hub with a setting angle. Functionally graded material (FGM) properties are considered along the height direction of the beam. The equations of stretching and bending motion are derived by Kane's method employing hybrid deformation variables. To validate the derived equations, natural frequencies of a rotating FGM pre-twisted beam are compared to those obtained by a commercial software ANSYS. The effects of the pre-twisted angle, slenderness ratio, hub radius, volume fraction exponent, and angular speed on the modal characteristics of the system are investigated with the proposed model.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.2
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• pp.16-29
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• 1995

In this study a tracked vehicle is idealized as a 2-dimensional 9-degrees-of-freedom model which takes into account the effects of HSU units, torsion bars, and track. For the model equations of motion are derived using Kane's method. By using the equations of motion, a numerical example is solved and results are compared to those obtained by using a general purpose multi body dynamic analysis program. The comparison study shows the reasonable coherence between the two results. which confirms the effectiveness of the model. With the model, dynamic response optimization is carried out. The objective function is the peak value of the vertical acceleration of the vehicle at the driver's seat, and the constraints are the wheel travel limits, the ground clearance. and the limits of other design variables. Three different sets of design variables are chosen and used for the optimization. The results show the attenuation of the acceleration peak value. Thus the procedure presented in this study can be utilized for the design improvement of the real system.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.377-377
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• 2010

FINEMET type nanocrystalline materials synthesized by controlled crystallization of amorphous ribbons[1] exhibit excellent soft magnetic properties making them attractive for technological applications. Present work reports the electronic structure studies of Co-substituted FINEMET to get information on the effect of successive Co substitution on local environment around Fe and Co atom by using near edge x-ray absorption fine structure (NEXAFS) and x-ray magnetic circular dichroism (XMCD) measurements. NEXAFS spectroscopy and XMCD measurements have been carried out at Fe $L_{3,2}$ and Co $L_{3,2}$-edges to investigate the chemical states and electronic structure of FINEMET [$(Fe_{100-x}Co_x)_{78}Si_9Nb_3Cu_1Ba$](0$L_{3,2}$-edge reveal that Fe is in 2+ state and in tetrahedral symmetry with other elements. The magnetic properties exhibiting soft magnetic behavior[2] are discussed on the basis of the electronic structure studied through XMCD.

• Asia pacific journal of information systems
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• v.29 no.3
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• pp.382-406
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• 2019

We study the antecedents to tie formation on an (Facebook-like) enterprise social media platform implemented to support cross-boundary connections. Research has produced mixed findings regarding the role of social media in cultivating bridging vs. closed networks. We examine the tie formation patterns of 1,386 enterprise social media users over a two-year period. Specifically, we observe who became (or chose not s become) "friends" with whom at the dyadic level and relate the decisions to various mechanisms that affect one's network to expand, constrain, or bridge. Using logistic and OLS regressions, we find that users tend to form ties via reciprocity and transitivity (with friends of friends), both of which help expand one's network. We also find strong networking tendency toward functional and hierarchical homophily (same business unit and same rank, respectively), which is likely to constrain one's network (closed network structure). We find that one's participation in various online interest groups is likely to open one's network (bridging network structure) while no evidence found for preferential attachment. Overall, we find that enterprise social media offers features, some of which are likely to foster bridging while others foster closed networks via different mechanisms.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.5
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• pp.615-623
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• 2004

This study was conducted for developing the emission factors of nitrogen oxide(NOx) and carbon monoxide (CO) from the combustion boilers burning liquefied natural gas (LNG). These emission factors were compared with those of U.S. EPA and European Environment Agency (EEA). NOx and CO concentration in the flow gas were measured using Kane-May, KM9106 and Thermo Environmental Instruments Inc., 42C-HL. Measurement were conducted at thirty industrial and commercial LNG boilers. Emission factors were calculated on the basis of fuel consumption (kg-pollutant/㎥-fuel burned). NOx concentration at industrial boiler was 14~125 ppm and it was measured as 35~125 ppm at commercial boiler. NOx emission factors of industrial boiler and commercial boiler were 1.84kg/$m^3$ and 2.09kg/$m^3$, respectively. NOx emission factor of commercial boiler was higher than that of industrial boiler. The NOx emission factors estimated in this study were lower than those of U.S. EPA and higher than those of EEA. Average CO emission factor of industrial boiler was 0.65 kg/$m^3$ and at commercial boiler it was 0.70kg/$m^3$, CO emission factor at industrial boiler was lower than that at commercial boiler.

• Fashion & Textile Research Journal
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• v.18 no.3
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• pp.272-281
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• 2016

From the year 2000 on, Seoul has aimed to be a fashion city, and thus has been supporting young designers through Seoul Fashion Creative Studio, Generation Next, Le Dome, Concept Korea, etc. London is famous for nurturing young designers through the joint help of government, schools and industries: Alexander McQueen, Christopher Kane and Peter Pilotto are successful cases. Therefore, this research aims to suggest a direction for policies aimed at helping young designers in the international market, on the basis of London's nurturing programs and ideas from a literature review and case studies. The results are below. Firstly, a step-by-step supporting program is recommended. Secondly, long-lasting, sustainable programs are considered essential to support designers after the end of their contracts. Thirdly, practical assistance is preferred to monetary funding in order to lighten the designers' lot and in the interests of transparency. The mentoring service should be strengthened for the designers to eventually become independent. The support should be tailor-made according to items. Fourthly, the supporting programs should be promoted. Fifthly, government and industries should collaborate. Sixthly, 'de minimis' against overlapped support should be legislated. For these, the change of supporting method can be helpful; an independent administrative organisation plans and collects funds from governments and companies. Through these programs and any subsequent studies, Seoul could become a fashion city where young designers play active roles at a global level.