• Genomics & Informatics
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• v.18 no.3
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• pp.32.1-32.7
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• 2020

The mitochondrial genome of a species is an essential resource for its effective conservation and phylogenetic studies. In this article, we present sequencing and characterization of the complete mitochondrial genome of a threatened labeonine fish, Cirrhinus reba collected from Khulna region of Bangladesh. The complete mitochondrial genome was 16,597 bp in size, which formed a circular double-stranded DNA molecule containing a total of 37 mitochondrial genes (13 protein-coding genes, 2 ribosomal RNA genes, and 22 transfer RNA genes) with two non-coding regions, an origin of light strand replication (OL) and a displacement loop (D-loop), similar structure with other fishes of Teleostei. The phylogenetic tree demonstrated its close relationship with labeonine fishes. The complete mitogenome of Cirrhinus reba (GenBank no. MN862482) showed 99.96% identity to another haplotype of Cirrhinus reba (AP013325), followed by 90.18% identity with Labeo bata (AP011198).

• Proceedings of the Acoustical Society of Korea Conference
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• 1996.06a
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• pp.59-62
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• 1996

A numerical study of a two-dimensional acoustic field is carride ort for a spinning vortex pair located neat a wall to investigate the effect of the wall from the spinning quadrupole source in unsteady vortical flows. Based on the known incompressible flow field, the perturbed compressible acoustic terms derived from the Euler equations are calculated. Non-reflecting boundary conditions on the free field and the solid boundary conditions are developed for a generalized curvilinear coordinates system to investigate the effect of a curced wall. It is concluded that the sound generated by the quadrupole sources of unsteady vortical flows in the presence of a flat wall or a circular cylinder can be calculated by using the source terms of hydrodynamic flow fluctuations in both near and far acoustic fields simultaneously.

• East Asian mathematical journal
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• v.39 no.4
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• pp.479-492
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• 2023

Although Euclidean plane geometry is implemented in the middle school course, there are three major problems in high school space geometry that can be intuitively taken for granted or misinterpreted as circular arguments. In order to solve this problem, this study proved three major problems using sets, Euclidean plane geometry, and parallel line postulates. This corresponds to a logical sequence and has mathematical and mathematical educational values. Furthermore, it will be possible to configure spatial geometry using sets, and by giving legitimacy to non-Euclidean spatial geometry, it will open the possibility of future research.

• Journal of Species Research
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• v.13 no.2
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• pp.127-130
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• 2024

The first complete mitogenome sequence of the Red-tongue Pit Viper (Gloydius ussuriensis) from Korea was characterized using next-generation sequencing. The mitogenome is a circular molecule (17,209 bp) with a typical vertebrate mitogenome arrangement, which consists of 2 ribosomal RNA genes (rRNA), 22 transfer RNA genes (tRNA), two non-coding regions (D-loop), and 13 protein-coding genes (PCGs). The base composition of the mitogenome is 32.7% of A, 27.5% of C, 13.9% of G, and 25.9% of T, with a slight AT bias(58.6%). This phylogenetic analysis infers that G. ussuriensis is in the same group as the Chinese G. ussuriensis (Accession No. KP262412) and is closely related to G. blomhoffi and other species of the genus Gloydius. In our study, the complete mitogenome sequence of Korean G. ussuriensis was characterized and we provided basic genetic information on this species.

• Steel and Composite Structures
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• v.51 no.3
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• pp.305-323
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• 2024

Previous experimental studies have effectively demonstrated the remarkable efficiency of the stiffened channel link in connecting circular columns and I-shaped beams. This research aims to present design criteria and assess the seismic properties of this specific connection type through numerical modeling. Various parameters, including stiffener type and geometric properties of the stiffened channel element, were duly taken into account. The findings from over 136 nonlinear finite element analyses (FEAs) reveal that the recommended detailing scheme reliably satisfies all the regulations specified for rigid beam-to-column connections in special moment frames.

• Journal of the Korea Concrete Institute
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• v.16 no.5 s.83
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• pp.697-707
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• 2004

Most bridge piers were practically designed and constructed with lap spliced longitudinal reinforcing steels before the 1992 seismic design provisions of Korea Bridge Design Specification were implemented. It has been known that lap splice of longitudinal reinforcement in the plastic hinge region is not desirable for seismic performance of RC bridge piers. The objective of this research is to evaluate the seismic performance of existing circular reinforced concrete bridge piers by the Quasi-static test and to propose the need of seismic retrofit of existing bridge piers through the damage level. Test specimens were nonseismically designed with the aspect ratio 4.0 which could induce the flexural failure mode. It was confirmed from this experiment that significant reduction of seismic performance was observed for test specimens with lap spliced longitudinal reinforcing steels. Pertinent seismic retrofit was determined to be needed for existing RC bridge piers with the lap-spliced of $50\%$ longitudinal reinforcing steels.

• Wind and Structures
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• v.26 no.4
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• pp.215-229
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• 2018

The appearance of a rivulet at the upper surface of a stay cable is responsible for rain-wind-induced vibration (RWIV) of cables of cable-stayed bridges. However, the formation mechanism of the upper rivulet and its aerodynamic effects on the stay cable has not been fully understood. Large eddy simulation (LES) method is used to investigate flow around and aerodynamics of a circular cylinder with an upper rivulet at a Reynolds number of 140,000. Results show that the mean lift coefficients of the circular cylinder experience three distinct stages, zero-lift stage, positive-lift stage and negative-lift stage as the rivulet located at various positions. Both pressure-induced and friction-induced aerodynamic forces on the upper rivulet are helpful for its appearance on the upside of the stay cable. The friction-induced aerodynamic forces, which have not been considered in the previous theoretical models, may not be neglected in modeling the RWIV. In positive-lift stage, the shear layer separated from the upper rivulet can reattach on the surface of the cylinder and form separation bubbles, which result in a high non-zero mean lift of the cylinder and potentially induces the occurrence of RWIV. The separation bubbles are intrinsically unsteady flow phenomena. A serial of small eddies first appears in the laminar shear layer separated from the upper rivulet, which then coalesces and reattaches on the side surface of the cylinder and eventually sheds into the wake.

• Wind and Structures
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• v.30 no.6
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• pp.617-631
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• 2020

Wake-induced aerodynamics of yawed circular cylinders with smooth and grooved surfaces in a tandem arrangement was studied. This pair of cylinders represent sections of stay-cables with smooth surfaces and high-voltage power conductors with grooved surfaces that are vulnerable to flow-induced structural failure. The study provides some insight for a better understanding of wake-induced loads and galloping problem of bundled cables. All experiments in this study were conducted using a pair of stationary section models of circular cylinders in a wind tunnel subjected to uniform and smooth flow. The aerodynamic force coefficients and vortex-shedding frequency of the downstream model were extracted from the surface pressure distribution. For measurement, polished aluminum tubes were used as smooth cables; and hollow tubes with a helically grooved surface were used as power conductors. The aerodynamic properties of the downstream model were captured at wind speeds of about 6-23 m/s (Reynolds number of 5×10⁴ to 2.67×10⁵ for smooth cable and 2×10⁴ to 1.01×10⁵ for grooved cable) and yaw angles ranging from 0° to 45° while the upstream model was fixed at the various spacing between the two model cylinders. The results showed that the Strouhal number of yawed cable is less than the non-yawed case at a given Reynolds number, and its value is smaller than the Strouhal number of a single cable. Additionally, compared to the single smooth cable, it was observed that there was a reduction of drag coefficient of the downstream model, but no change in a drag coefficient of the downstream grooved case in the range of Reynolds number in this study.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.4
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• pp.1-11
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• 2008

In this paper, we propose the new eye detection method by using adaboost (adaptive boosting) method. Also, to reduce the false alarm rate which identifies the non-eye region as genuine eye that is the Problems of previous method using conventional adaboost, we proposed the post processing methods which used the cornea specular reflection and determined the optimized ratio of eye detecting box. Based on detected eye region by using adaboost, we performed the double circular edge detector for localizing a pupil and an iris region at the same time. Experimental results showed that the accuracy of eye detection was about 98% and the processing time was less than 1 second in mobile device.

• 한국가시화정보학회:학술대회논문집
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• 2007.11a
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• pp.134-137
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• 2007

The temporal evolution of wake behind a circular cylinder oscillating rotationally with a relatively high forcing frequency has been investigated experimentally using a dynamic PIV technique. Experiments were carried out with varying the frequency ratio $F_R\;(=f_f/f_n)$ in the range from 0.0 (stationary) to 1.6 at oscillation amplitude of ${\theta}_A=30^{\circ}$ and Reynolds number of $Re=4.14{\times}10^3$. Depending on the forcing condition ($F_R$), the flow was divided into three regimes; non-lock-on ($F_R=0.4$), transition ($F_R=0.8$, 1.6) and lock-on regimes ($F_R=1.0$) with markedly different flow structure in the near-wake region behind the cylinder. When the frequency ratio was less than 1.0 ($F_R{\le}1.0$), the rotational oscillatory motion of the cylinder decreased the length of the vortex formation region and enhanced the mutual interaction between large-scale vortices across the wake centerline. The entrainment of ambient fluid seemed to play an important role in controlling the near-wake flow and shear-layer instability. However, the flow characteristics changed markedly beyond the lock-on flow regime ($F_R=1.0$) due to high-frequency forcing. At $F_R=1.6$, the mutual interactions between the vortices shed from both sides of the cylinder were not so strong. Thereby, the flow entrainment and momentum transfer into the wake center region were reduced. In addition, the size of the large-scale vortices decreased since the lateral extent of the wake was suppressed.