• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.7
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• pp.1221-1228
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• 2016

In this paper, we propose a modified rhombus slot UWB(Ultra Wide Band) antenna with fork-shaped feeding structure. The proposed antenna is modified rhombus slot structure and fork-shaped feeding structure to get ultra-wideband characteristics for UWB communication. Modified rhombus slot structure consists of slot shaped which eliminated upper and lower part of the basic rhombus slot. The antenna is designed on an FR-4 substrate of which the dielectric constant is 4.4, and its overall size is $34mm(W_1){\times}34mm(L_1){\times}1mm(t)$, and its slot antenna size is $30mm(W_2){\times}16.75mm(L_3+L_4)$. After carrying out the simulation of each parameters, optimized values are obtained. From the fabricated and measured results, return loss of the proposed antenna satisfied Return Loss -10dB in 3.1 ~ 10.6 GHz. And measured results of gain and radiation patterns characteristics displayed for operating bands.

• Journal of the Korean Burn Society
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• v.23 no.1
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• pp.25-29
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• 2020

This paper presents our clinical experiences for reconstruction of the linear depressed postburn scar band by rhombus subcutaneous pedicle skin flap (RSPF). We report new RSPF, it's versatility, and effectiveness for correction of the mild to moderate linear depressed postburn scar band. To correct the postburn scar band, we have newly designed the Rhombus Subcutaneous Pedicle Skin Flap (RSPF), which is made as rhombus-shaped skin flap on the inside of scar band. After excision of burn scar band, the each vertex of RSPF flap is advanced into the skin defects at apex of extended skin incision, which is starting from the upper and lower portion of the removed burn scar band at a near right angle. This flap can add more extra skin to adjacent superior and inferior area of excised scar band. We have experienced 2 cases of RSPF for reconstruction of linear depressed postburn scar band deformities in lower extremity. After 3 weeks to 3 months postoperative follow ups, relatively satisfactory results were obtained in all cases. We had successfully reconstructed the linear depressed postburn scar postburn band of lower extremity using the rhombus subcutaneous pedicle skin flap. For the correction of mild to moderate sized linear depressed postburn scar band deformities in extremity, the RSPF is simple, and very effective without donor morbidity.

• Structural Engineering and Mechanics
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• v.83 no.1
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• pp.53-66
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• 2022

The main objective of the present research was investigating the effects of a floating wave barrier installed in front of an offshore jacket structure on the wave height, base shear, and overturning moment. A jacket model with the height of 4.55 m was fabricated and tested in the 402 m-long wave flume of NIMALA marine laboratory. The jacket was tested at the water depth of 4 m subjected to the random waves with a JONSWAP energy spectrum. Three input wave heights were chosen for the tests: 20 cm, 23 cm, and 28 cm. Two different cross sections with the same area were selected for the wave barrier: square and rhombus. Results showed that the average decrease in the jacket's base shear due to the presence of a floating wave barrier with square and rhombus cross section was 24.67% and 34.29%, respectively. The use of wave barriers with square and rhombus cross sections also resulted in 19.78% and 33.11% decrease in the jacket's overturning moment, respectively. Hence, it can be concluded that a floating wave barrier can significantly reduce the base shear and overturning moment in an offshore jacket structure; and a rhombus cross section is more effective than an equivalent square section.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.152.2-152.2
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• 2005

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.630-632
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• 2016

In this paper, we propose a modified rhombus slot UWB(Ultra Wide Band) antenna with fork-shaped feeding structure. The proposed modified rhombus slot structure is eliminated upper and lower part of the basic rhombus slot shape to get ultra-wideband characteristics for UWB communication. Also, feeding structure is used to fork-shaped structure to get ultra-wideband characteristics. The antenna is designed on an FR-4 substrate of which the dielectric constant is 4.4, and its overall size is $34mm(W1){\times}34mm(L1){\times}1mm(t)$, and its slot antenna size is $30mm(W2){\times}16.75mm(L3+L4)$. After the optimized process, the proposed antenna is fabricated and measured. Measured result. fabricated antenna satisfied -10 dB impedance bandwidth in UWB frequency band (3.1 ~ 10.6 GHz ). And measured results of gain and radiation patterns characteristics displayed determined for operating bands.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.2
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• pp.175-180
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• 2018

In this paper, a feature extraction and object recognition algorithm using only morphological operations is proposed. The morphological operations used in feature extraction are erosion and dilation, opening and closing combining erosion and dilation, and morphological edge and skeleton detection operation. In the process of recognizing an object based on features, a pooling operation is applied to reduce the dimension. Among various structuring elements, $3{\times}3$ rhombus, $3{\times}3$ square, and $5{\times}5$ circle are arbitrarily selected in morphological operation process. It has confirmed that the proposed algorithm can be applied in object recognition fields through experiments using Internet images.

• Bulletin of the Korean Chemical Society
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• v.33 no.4
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• pp.1317-1320
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• 2012

Well-defined solid-state microcrystalline structures from bispyridyl Zn-porphyrin have been successfully synthesized. The coordinative interactions between pyridine and Zn are main responsible for this translation of porphyrin molecular building blocks to crystalline microscopic objects. The hexagonal plates are obtained from acetonitrile and rhombus plates are grown from toluene solution. With a simple manipulation during the microcrystal growth, such as growth temperature and time, the morphologies can be controlled by adopting different molecular packing. Consequently, morphologies of microcrystals have been diversified.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4936-4941
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• 2015

This study(I) has analyzed hydraulic characteristics with pier shapes by the bridge construction. The pier shapes are classified into total six types such as square, rhombus, octagon, oval, round, and no-piers. One-dimensional model(HEC-RAS) and two-dimensional model (RMA-2) were employed to analyze hydraulic characteristics around bridge piers. Square and rhombus shapes of piers showed velocity vectors in the upstream direction, which has a significant impact on the river bed changes by erosion and sediment transport around the piers. The flow characteristics of the oval type pier was most similar to that of no-pier situation almost without disrupting the river flow. This analysis can help to select pier types in the new bridge construction for the future.

• Journal of Elementary Mathematics Education in Korea
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• v.15 no.2
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• pp.361-383
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• 2011

This study is on teaching about the areas of plane figures through open instruction, which aims to discover the pedagogical meanings and implications in the application of open methods to math classes by running the Math A & B classes regarding the areas of parallelogram, triangle, trapezoid and rhombus for fifth graders of elementary school through open instruction method and analyzing the educational process. This study led to the following results. First, it is most important to choose proper open-end questions for classes on open instruction methods. Teachers should focus on the roles of educational assistants and mediators in the communication among students. Second, teachers need to make lists of anticipated responses from students to lead them to discuss and focus on more valuable methods. Third, it is efficient to provide more individual tutoring sessions for the students of low educational level as the classes on open instruction methods are carried on. Fourth, students sometimes figured out more advanced solutions by justifying their solutions with explanations through discussions in the group sessions and regular classes. Fifth, most of students were found out to be much interested in the process of thinking and figuring out solutions through presentations and questions in classes and find it difficult to describe their thoughts.

• Honam Mathematical Journal
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• v.39 no.3
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• pp.431-442
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• 2017

For a quadrilateral P, we consider the centroid $G_0$ of the vertices of P, the perimeter centroid $G_1$ of the edges of P and the centroid $G_2$ of the interior of P, respectively. We denote by M the intersection point of two diagonals of P. If P is a parallelogram, then we have $G_0=G_1=G_2=M$. Conversely, one of $G_0=M$ and $G_2=M$ implies that P is a parallelogram. In this paper, we show that $G_1=M$ is also a characteristic property of parallelograms.