• Structural Engineering and Mechanics
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• v.39 no.3
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• pp.427-447
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• 2011

The progressive collapse phenomenon is generally regarded as dynamic. Due to the impracticality of nonlinear dynamic computations for practitioners, an interest arises for the development of equivalent static pushover procedures. The present paper proposes a methodology to identify such a procedure for sudden column removals, using energetic evaluations to determine the pushover loads to apply. In a dynamic context, equality between the cumulated external and internal works indicates a vanishing kinetic energy. If such a state is reached, the structure is sometimes assumed able to withstand the column removal. Approximations of these works can be estimated using a static computation, leading to an estimate of the displacements at the zero kinetic energy configuration. In comparison with other available procedures based on such criteria, the present contribution identifies loading patterns to associate with the zero-kinetic energy criterion to avoid a single-degree-of-freedom idealisation. A parametric study over a family of regular steel structures of varying sizes uses non-linear dynamic computations to assess the proposed pushover loading pattern for the cases of central and lateral ground floor column failure. The identified quasi-static loading schemes are shown to allow detecting nearly all dynamically detected plastic hinges, so that the various beams are provided with sufficient resistance during the design process. A proper accuracy is obtained for the plastic rotations of the most plastified hinges almost independently of the design parameters (loads, geometry, robustness), indicating that the methodology could be extended to provide estimates of the required ductility for the beams, columns, and beam-column connections.

• Earthquakes and Structures
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• v.14 no.5
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• pp.411-424
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• 2018

This study explores the inelastic behavior of systems with flexible base. The use of a single degree of freedom system (ESDOF) with equivalent ductility to represent the response of flexible base systems is discussed. Two different equations to compute equivalent ductility are proposed, one which includes the contribution of rigid body components, and other based on the overstrength of the structure. In order to asses the accuracy of ESDOF approach with the proposed equations, the behavior of a 10-story regular building with reinforced concrete (RC) moment resisting frames is studied. Local and global ductility capacity and demands are used to study the modifications introduced by base flexibility. Three soil types are considered with shear wave velocities of 70, 100 and 250 m/s. Soil-foundation stiffness is included with a set of springs on the base (impedance functions). Capacity curves of the building are computed with pushover analysis. In addition, non linear time history analysis are used to asses the ductility demands. Results show that ductility capacity of the soil-structure system including rigid body components is reduced. Base flexibility does not modify neither yield and maximum base shear. Equivalent ductility estimated with the proposed equations is fits better the results of the numerical model than the one considering elastoplastic behavior. Modification of beams ductility demand due to base flexibility are not constant within the structure. Some elements experience reduced ductility demands while other elements experience increments when flexible base is considered. Soil structure interaction produces changes in the relation between yield strength reduction factor and structure ductility demand. These changes are dependent on the spectral shape and the period of the system with fixed and flexible base.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.1
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• pp.55-61
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• 2008

A real-time three-dimensional vision is a passive system, which would support various applications including collision avoidance, home networks. It is a good alternative of active systems, which are subject to interference in noisy environments. In this paper, we designed a SAD correlator with respect to resource usage for a real-time three-dimensional vision system. Regular structures, linear data flow and abundant parallelism make the correlation algorithm a good candidate for a reconfigurable hardware. We implemented two versions of SAD correlator in HDL and synthesized them to determine resource requirements and performance. From the experiment we show that the SAD correlator fits into reconfigurable hardware in marginal cost and can handle about 30 frames/sec with $640{\times}480$ images.

• Journal of Korean Elementary Science Education
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• v.28 no.2
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• pp.178-186
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• 2009

The science writing is recognized for useful learning method to boost up scientific thinking for all class course as well as traditional lecture and experiment. Many researches say that science writing is helpful to extend students' science knowledge and scientific attitude. By the way, the researchers thought that science writing can also improve the science process skill if students participate in delicately organized learning program. In this study, we had contrived the teaching & learning strategy of science writing to improve science process skills. The learning program covers all field of Klopfer's process skills with various forms of writing; explaining writing, logical writing, critical writing, and creative writing. The learning program has been developed for 5th grade students in the regular classes in order to enhance science process skills as well as knowledge and scientific attitude. Not to miss any process skill or various kinds of writing, we used 3 dimensional frame. The axes of the frames are science process skills, forms of writing, and science curriculum contents. The students are given the final writing theme at the beginning of each chapter. They drill science process skills step by step during the classes, and have a chance to talk each other before the final writing. They practice writing skills from one sentence to full article by degrees. The effect of the program was examined by students' work and TSPS (Test of Science Process Skill). The result showed that 5th grade students had a meaningful progress in science process skills as well as knowledge and scientific attitude. we could confirm it with examining students' work in the class.

• Journal of the Korean Society of Clothing and Textiles
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• v.40 no.6
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• pp.994-1009
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• 2016

Applying the S-O-R Model within an online context, a hypothesized model incorporates three review characteristics (perceived concreteness, exaggeration, and sufficient quantity of reviews) for apparel products in order to present their impact on consumer perceptions of review usefulness and consumer attitude toward and patronage intent for the online stores hosting the reviews. An online survey of Korean women (N=299) reported their experiences in purchasing apparel products online and reading apparel reviews on a regular basis. Testing of the hypothesized model showed the usefulness of reviews were determined by two review characteristics (S: perceived concreteness and sufficient quantity of reviews); however, the negative effect of exaggerated reviews were insignificant. In addition, the perceived usefulness of reviews (O-cognitive) hosted by an online store influenced online store attitude (O-affective) which subsequently led to online store patronage intent (R). This study systemically advances online retail literature by showing how the characteristics of online reviews (as a part of the online store environment) can influence attitude toward online stores and patronage intent for online stores. Long term relationships with consumers can be achieved through the building of mechanisms to enhance the perceived usefulness of reviews by employing the strategies of hosting concrete reviews and offering a sufficient quantity of reviews. This study addresses removes research gaps by testing an adapted the S-O-R Model that frames review information as an element of an online store environment using a large sample.

• Journal of Korea Game Society
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• v.12 no.5
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• pp.79-88
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• 2012

In this paper, we present a real-time hand pose recognition method to provide an intuitive user interface through hand poses or movements without a keyboard and a mouse. For this, the areas of right and left hands are segmented from the depth camera image, and noise removal is performed. Then, the rotation angle and the centroid point of each hand area are calculated. Subsequently, a circle is expanded at regular intervals from a centroid point of the hand to detect joint points and end points of the finger by obtaining the midway points of the hand boundary crossing. Lastly, the matching between the hand information calculated previously and the hand model of previous frame is performed, and the hand model is recognized to update the hand model for the next frame. This method enables users to predict the hidden fingers through the hand model information of the previous frame using temporal coherence in consecutive frames. As a result of the experiment on various hand poses with the hidden fingers using both hands, the accuracy showed over 95% and the performance indicated over 32 fps. The proposed method can be used as a contactless input interface in presentation, advertisement, education, and game applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7A
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• pp.683-694
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• 2002

In this paper, a digital image compression codec using 2D DWT(Discrete Wavelet Transform) is designed using the FPGA technology for real time operation The implemented image compression codec using wavelet decomposition consists of a wavelet kernel part for wavelet filtering process, a quantizer/huffman coder for quantization and huffman encoding of wavelet coefficients, a memory controller for interface with external memories, a input interface to process image pixels from A/D converter, a output interface for reconstructing huffman codes, which has irregular bit size, into 32-bit data having regular size data, a memory-kernel buffer to arrage data for real time process, a PCI interface part, and some modules for setting timing between each modules. Since the memory mapping method which converts read process of column-direction into read process of the row-direction is used, the read process in the vertical-direction wavelet decomposition is very efficiently processed. Global operation of wavelet codec is synchronized with the field signal of A/D converter. The global hardware process pipeline operation as the unit of field and each field and each field operation is classified as decomposition levels of wavelet transform. The implemented hardware used FPGA hardware resource of 11119(45%) LAB and 28352(9％) ESB in FPGA device of APEX20KC EP20k600CB652-7 and mapped into one FPGA without additional external logic. Also it can process 33 frames(66 fields) per second, so real-time image compression is possible.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.2
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• pp.163-174
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• 2012

This study focused on the nutrition knowledge, food purchase behaviors, and dietary habits of 213 housewives (41 women under 39 years, 98 women 40~49 years, and 74 women over 50 years). Younger housewives held more special jobs, whereas older housewives worked as housewives or had no jobs ($p$<0.05). The average monthly income of the three family groups was 3,000,000~5,000,000 won, and the monthly dietary expenditure for all three groups was 200,000~500,000 won. Familial frames for the three groups was nuclear family (over 80%), but housewives younger than 39 years (19.5%) lived together with their parents and let them take care of their children. Housewives (over 50 years) prepared a balanced diet for every meal, utilized less drastic cooking methods to prevent loss of nutrients, and shopped at many places in order to save money on various food materials. Further, they purchased food materials that resulted in the least amount of left overs. On the other hand, housewives under 39 years visited large supermarkets and purchased cooked foods more than other groups. Housewives under 39 years considered nutrients content as the most important factor when purchasing food materials, whereas 74.5% of housewives between 40~49 years and 51.4% of housewives over 50 years put the most importance on flavor ($p$<0.05). Housewives under 39 years were interested in manufacture date, nutrient content, and food price, in decreasing order, whereas housewives between 40~49 years and over 50 years were interested in manufacture date, food prices, and nutrient content. Older housewives were interested in brown rice and fruits, whereas younger housewives under 39 years were interested in meat, fish, eggs, fried foods, and fast food. Older housewives over 50 years did not consume fried foods more than two times per week and consumed three regular meals more often than younger housewives. Accordingly, for younger housewives, it is necessary that healthy foods be cooked for their families.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.2
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• pp.194-201
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• 1995

In order to make clear the resistance of bag nets, the resistance R of bag nets with wall area S designed in pyramid shape was measured in a circulating water tank with control of flow velocity v and the coefficient k in $R=kSv^2$ was investigated. The coefficient k showed no change In the nets designed in regular pyramid shape when their mouths were attached alternately to the circular and square frames, because their shape in water became a circular cone in the circular frame and equal to the cone with the exception of the vicinity of frame in the square one. On the other hand, a net designed in right pyramid shape and then attached to a rectangular frame showed an elliptic cone with the exception of the vicinity of frame in water, but produced no significant difference in value of k in comparison with that making a circular cone in water. In the nets making a circular cone in water, k was higher in nets with larger d/l, ratio of diameter d to length I of bars, and decreased as the ratio S/S_m$ of S to the area $S_m$ of net mouth was increased or as the attack angle 9 of net to the water flow was decreased. But the value of ks15m was almost constant in the region of S/S_m=1-4$ or $\theta=15-90^{\circ}$ and in creased linearly in S/S_m>4 or in $\theta<15^{\circ}$ However, these variation of k could be summarized by the equation obtained in the previous paper. That is, the coefficient $k(kg\;\cdot\;sec^2/m^4)$ of bag nets was expressed as $$k=160R_e\;^{-01}(\frac{S_n}{S_m})^{1.2}\;(\frac{S_m}{S})^{1.6}$$ for the condition of $R_e<100$ and $$k=100(\frac{S_n}{S_m})^{1.2}\;(\frac{S_m}{S})^{1.6}$$ for $R_e\geq100$, where $S_n$ is their total area projected to the plane perpendicular to the water flow and $R_e$ the Reynolds' number on which the representative size was taken by the value of $\lambda$ defined as $$\lambda={\frac{\pi d^2}{21\;sin\;2\varphi}$$ where If is the angle between two adjacent bars, d the diameter of bars, and 21 the mesh size. Conclusively, it is clarified that the coefficient k obtained in the previous paper agrees with the experimental results for bag nets.