• Journal of The Korean Association For Science Education
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• v.26 no.4
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• pp.510-517
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• 2006

This study investigated the influences of situational interest, attention, and cognitive effort on drawing as a method to assist students to connect and integrate multiple external representations provided in learning chemical concepts. Seventh graders (N=178) at two coed middle schools were taught about the "Boyle's Law" and the "Charles's Law" for two class hours through drawing. They observed macroscopic phenomena through demonstrations. After these observations, they drew their mental model from the external verbal representation, and then compared their drawings with external visual representation. The tests assessing situational interest, attention, cognitive effort, and conceptual understanding were administered as post-tests. Correlation and path analyses supported a causal model which situational interest had a positive direct effect on attention to the drawing. Attention led to conceptual understanding directly as well as through cognitive effort. These results suggest that situational interest may be induced by drawing first of all, and attention and cognitive effort may be direct causes of conceptual understanding in drawing. Educational implications are discussed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5A
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• pp.881-885
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• 2006

Rain-wind induced cable vibration can cause serious problems in cable-stayed bridges. Externally attached dampers have been used to provide an effective means to suppress the vibration of relatively short stay-cables. For very long stay-cables, however, such damper systems are rendered ineffective, as the dampers need to be attached near the end of cables for aesthetic reasons. This paper investigates a new control system to mitigate the cable vibration. The proposed control system which consists of a laminated rubber bearing and an internal damper may be installed inside of the cable anchorage. A simple analytical model of the cable-damper system is developed first based on the taut string representation of the cable. The response of a cable with the proposed control system is obtained and then compared to those of the cable with and without an external passive damper. The proposed stay-cable vibration control system is shown to perform better than the optimal passive viscous damper, thereby demonstrating its applicability in large cable-stayed bridges for mitigation of rain-wind induced vibration of stay-cables.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.7
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• pp.110-116
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• 1994

In this paper a Duty Effective Overlap Scanning method (DEOS) for the improvement of driving efficiency of LC displays which have the RMS voltage responding characteristics is proposed and new processing method of data signals for optimum application of this method is also proposed. Proposed method has a few advantages such as the increment of duty ratio the increment of driving power loaded on LC cell and the decrement of RMS voltage error rate caused by signal attenuation on electrodes composing of display when compared with the conventional method which is called as optimum voltage amplitude selection method. And also by adopting new data signal processing method which has 3 kinds of voltage levels additional advantage much improving crosstalk phenomenon which is the most serious problems of simple matrix structured display is obtained. For the characteristic estimation new mathematical representation for new overlap scanning method and data signal processing method are induced and defined. And by the defined formula and simulation the characteristics of the proposed method and the conventional method are compared and analyzed. As a result of estimation this new method being able to optimize the overlap rate of scan signal and using 3 levels of data signals has the characteristic which can improve the driving efficiency of LC displays.

• Wind and Structures
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• v.31 no.3
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• pp.217-227
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• 2020

Based on translation models, both Gaussian and non-Gaussian wind fields are generated using spectral representation method for investigating the influence of non-Gaussian characteristics and directivity effect of wind load on fatigue damage of wind turbine. Using the blade aerodynamic model and multi-body dynamics, dynamic responses are calculated. Using linear damage accumulation theory and linear crack propagation theory, crack initiation life and crack propagation life are discussed with consideration of the joint probability density distribution of the wind direction and mean wind speed in detail. The result shows that non-Gaussian characteristics of wind load have less influence on fatigue life of wind turbine in the area with smaller annual mean wind speeds. Whereas, the influence becomes significant with the increase of the annual mean wind speed. When the annual mean wind speeds are 7 m/s and 9 m/s at hub height of 90 m, the crack initiation lives under softening non-Gaussian wind decrease by 10% compared with Gaussian wind fields or at higher hub height. The study indicates that the consideration of the influence of softening non-Gaussian characteristics of wind inflows can significantly decrease the fatigue life, and, if neglected, it can result in non-conservative fatigue life estimates for the areas with higher annual mean wind speeds.

• School Mathematics
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• v.11 no.4
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• pp.607-623
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• 2009

This study aims to investigate a child's informal knowledge of carrying and borrowing in additive calculations. The additive word problems including three types of calculations are posed a child that is the first grader and has no lessons about carrying and borrowing. By analysing his answers, his informal knowledge, that is his methods and strategies for calculating the additive problems are revealed. As a result, conceptual aspects and procedural aspects of his informal knowledge are recognized, and the didactical implications are induced for connecting his informal knowledge and the formal knowledge about carrying and borrowing.

• International Journal of Naval Architecture and Ocean Engineering
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• v.2 no.2
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• pp.68-74
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• 2010

The development of a numerical model using the fractional area/volume obstacle representation (FAVOR) method for predicting a nearshore current field bounded by complicated geometric shapes, and a three-dimensional (3D) beach evolution was described in this article. The 3D model was first tested against three cases to simulate the nearshore current fields around coastal structures, a river mouth, and a large scale cusp bathymetry. Then, the morphodynamic model tests, which are adopting the nearshore current model, were applied for the computations of beach evolution around a detached breakwater and two groins. It was confirmed that the presented model associated with the FAVOR method was useful to predict the nearshore current field in the vicinity of the complicated geometric shapes. Finally, the model was applied to a tombolo formation in a field site of Kunnui fishery port, which is located in Hokkaido, Japan.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.12 s.255
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• pp.1518-1525
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• 2006

Finite element analyses of structures made of the fiber reinforced composites require an adequate method to characterize the high anisotropic behavior induced by one or several layers of fiber cords with different spatial orientation embedded in a rubber matrix. This paper newly proposes a continuum based rebar element considering change of the orientation of the fiber during deformation of the composite. The mechanical behavior of the embedded fiber is modeled using two-node bar elements in order to consider the relative deformation and spatial orientation of the embedded fiber. For improvement of the analysis accuracy, the load-displacement curve of fiber is applied to the stiffness matrix of fiber. A finite element program is constructed based on the total Lagrangian formulation considering both geometric and material nonlinearity. Finite element analyses of the tensile test are carried out in order to evaluate the validity of the proposed method. Analysis results obtained with the proposed method provides realistic representation of the fiber reinforced rubber composite compared to results of other two models by the Halpin-Tsai equation and a rebar element in ABAQUS/Standard.

• Journal of The Geomorphological Association of Korea
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• v.19 no.1
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• pp.109-121
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• 2012

Human responses, such as construction of levees, are a spatial representation of the place vulnerability which is induced by a geomorphic hazard like flooding. Human responses include all forms of human activities to reduce the place vulnerability and they seem to be related with reducing vulnerability rather than reducing geomorphic hazards. Diverse human responses to the perceived environment bring about changes in the place vulnerability. People respond spatially to their vulnerability of the place in diverse ways from their experience and perceived risk. Human responses have quantitative possibilities in predicting and modeling the place vulnerability. Building the model of a dynamic place vulnerability to the diverse geomorphic hazards requires basic maps of geomorphic processes and human responses in the region.

• Journal of Broadcast Engineering
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• v.26 no.7
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• pp.838-843
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• 2021

This paper presents an algorithm for effective retrieval of score information to an input score image. The originality of the proposed algorithm is that it is designed to be robust to recognition errors by an OMR (Optical Music Recognition), while existing methods such as pitch histogram requires error induced OMR result be corrected before retrieval process. This approach helps people to retrieve score without training on music score for error correction. OMR takes a score image as input, recognizes musical symbols, and produces structural symbolic notation of the score as output, for example, in MusicXML format. Among the musical symbols on a score, it is observed that filled noteheads are rarely detected with errors with its simple black filled round shape for OMR processing. Barlines that separate measures also strong to OMR errors with its long uniform length vertical line characteristic. The proposed algorithm consists of a descriptor for a score and a similarity measure between a query score and a reference score. The descriptor is based on note-count, the number of filled noteheads in a measure. Each part of a score is represented by a sequence of note-count numbers. The descriptor is an n-gram sequence of the note-count sequence. Simulation results show that the proposed algorithm works successfully to a certain degree in score image-based retrieval for an erroneous OMR output.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.2
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• pp.137-150
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• 1997

The problem of electromagnetic coupling into a thin conducting wire through a slot in an infinite conducting is analyzed by use of MPIE(mixed potential integral equation) and two- dimensional moment method using subsectional(rooftop) basis functions. The equivalent circuit is derived using a center-repesentation method which is valid in a narrow slot case. The equi- valent magnetic currents on the slot and the induced currents on the wire are caculated respec- tively, for the TM wave is incident upon the slot with arbitrary angle of incidence. The theoretical transmission coefficients of transmission line which is composed of thin-wire and infinite conducting plate with a narrow slot are compared and found to be in good agreement with experimental results.