• Journal of the Korea Institute of Military Science and Technology
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• v.26 no.2
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• pp.122-128
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• 2023

The target must be located within the main-lobe of the antenna in order to measure the direction of the target by using sum-delta monopulse technique. The most common way if the target is located within the main-lobe is to compare the amplitude of the sum channel received signal with the delta channel received signal. However, in the case of the single-ring circular array antenna, it is difficult to apply the conventional method due to its structural limitation where antenna elements do not exist in the center of the array. In this paper, we proposed a novel method to identify whether a target is located within the main-lobe by appropriately adjusting the feeding amplitude of each element constituting the single-ring circular array antenna through the particle swarm optimization method. Simulation results showed that the proposed method can determine whether the target is located within the main-lobe of the single-ring circular array antenna.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.9
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• pp.884-890
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• 2008

A new guidance law to reach circular target area with grazing angle constraint is proposed as one of midcourse guidance laws of unmanned air vehicles. The purpose of the law is to control the grazing angle between the velocity vector of the vehicle and the line of sight to the aiming point, the center of the circular target area, when the vehicle passes any point on the circle. The optimal solution is derived based on the optimal control theory minimizing a range weighted control energy subject to the nonlinear dynamic equations of the vehicle approaching to the circular target area with grazing angle constraint. The major properties including a convergence of the solution are examined and the performance of the law applied to some typical scenarios is shown by the numerical simulation.

• Journal of Korea Water Resources Association
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• v.54 no.1
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• pp.15-25
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• 2021

The purpose of this study was to present the necessity and effect of culvert fishway, based on the absence of design criteria for it which fishes can pass. As an attempt for this purpose, circular culvert fishway were designed hydraulically to meet the passage condition for selected target fish species, and post-monitoring was performed to confirm its effectiveness. In the case of general circular culvert without weir baffles, the target fish species cannot pass because of the constant depth and velocity in the entire reach of the circular culvert, so it was confirmed that resting pools must be installed to help fish passage. In the case of circular culvert with weir baffles, the depth and the mean velocity in resting pool increased by about 240% and decreased by about 70% respectively, which not only satisfied the passage conditions of Zacco platypus that can swim at more than 10 times the speed of body length for 1 to 5 seconds, but also confirmed that various river fish could pass. Post-monitoring results of the restoration reach and fish capture monitoring surveys of circular culvert fishway demonstrated that the target fish species, Zacco platypus, can pass through it.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.1
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• pp.59-66
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• 2000

In a previous paper, we have examined the effects of nozzle configuration and jet to jet spacing on the heat transfer of 1 row of circular water jets. In this paper, experiments have been conducted to obtain the effects of nozzle to target plate distances on the heat transfer of 1 row of 3 jets and 1 row of 5 jets. The nozzle configurations are Cone type, Reverse cone type and Vertical circular type. Nozzle to target plate distance H was varied from 16 mm(H/D=2) to 80mm(H/D=10). For fixed value of mass flow rate and nozzle to target plate distance, larger values of average Nusselt number were obtained for the smaller jet to jet spacing. For the array of water jets, the average heat transfer was decreased slightly with increasing nozzle to target plate distance at low jet velocity of $\textrm{V}_{o}$=3 m/s. However, except for $\textrm{V}_{o}$=8 m/s of 1 row of 5 jets, it was increased with increasing nozzle to target plate distance at high jet velocity of $\textrm{V}_{o}$$\geq$6m/s. We proposed to apply the nozzle configuration of maximum average heat transfer to each nozzle to target plate distance for 1 row of 3 jets, and, it was Reverse cone type nozzle for 1 row of 5 jets(Reynolds number$\geq$36000).

• 한국전산유체공학회:학술대회논문집
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• 2004.03a
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• pp.208-213
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• 2004

The HANARO, multi-purpose research reactor, 30 MWth open-tank-in- pool type, is under normal operation since it reached the initial critical in February 1995. The HANARO is planning to produce a fission moly-99 of radio isotopes, a mother nuclide of Tc-99m, a medical isotope and is under developing a target handling tool for loading and unloading it in a circular flow tube (OR-5). A guide tube is extended from the reactor core to the top of the reactor chimney for easily un/loading a target under the reactor normal operation. But active coolant through the core can be quickly raised up to the top of the chimney through the guide tube by jet flow. This paper is described an analytical analysis to calculate the hole size of a orifice inserted in the circular irradiation hole and to study the flow characteristics through the guide tube under reactor normal operation and loading the target. As results, the results show that the hole size of orifice was 31 mm of the inner diameter to suppress the guide tube jet flow and the coolant safely cooled the target of fission moly after inserting the orifice to the flow tube.

• 한국전산유체공학회:학술대회논문집
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• 2004.03a
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• pp.214-219
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• 2004

The HANARO, a multi-purpose research reactor of 30 MWth, open-tank-in-pool type, has been under normal operation since its initial criticality in February, 1995. The HANARO is composed of inlet plenum, grid plate, core channel with flow tubes and chimney. The reactor core channel is located at about twelve m (12 m) depth of the reactor pool and cold by the upward flow that the coolant enters the lower inlet of the plenum, rises up through the grid plate and the core channel and exit through the outlet of chimney. A guide tube is extended from the reactor core to the top of the reactor chimney for easily un/loading a target under the reactor normal operation. But active coolant through the core can be Quickly raised up to the top of the chimney through the guide tube by jet flow. This paper is described an analytical analysis to study the flow behavior through the guide tube under reactor normal operation and unloading the target. As results, it was conformed through the analysis results that the flow rate, about fourteen kilogram per second (14 kg/s) suppressed the guide tube jet and met the design cooling flow rate in a circular flow tube, and that the fission moly target cooling flow rate met the minimum flow rate to cool the target.

• Biomedical Science Letters
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• v.10 no.2
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• pp.65-73
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• 2004

I report that single-stranded antisense as a part of large circular (LC-) genomic DNA of recombinant M13 phage exhibits enhanced stability, sequence specific antisense activity, and no need for target site search. A cDNA fragment (708 bp) of rat TNF-$\alpha$ was inserted into a phagemid vector, and TNF-$\alpha$ antisense molecules (TNF$\alpha$-LCAS) were produced as single-stranded circular DNA. When introduced into a rat monocyte/macrophage cell line, WRT7/P2, TNF$\alpha$-LCAS was able to ablate LPS-induced TNF-$\alpha$ mRNA to completion. The antisense effect of TNF$\alpha$-LCAS was shown to be sequence-specific because expressions of three control genes ($\beta$-actin, GAPDH and IL-1$\beta$) were not significantly altered by the antisense treatment. Further, TNF$\alpha$-LCAS was found to be highly efficacious as only 0.1 $\mu$g (0.24 nM) of TNF$\alpha$-LCAS was sufficient to block TNF-$\alpha$ expression in 1$\times10^5$ WRT7/P2 cells. I have also observed specific antisense activity in reduction of NF-$\kappa$B gene expression. The results suggest that an antisense sequence as a part of single-stranded circular genomic DNA has a specific antisense activity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.474-480
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• 2019

We propose a method to evaluate a Modulation Transfer Function (MTF) using a circular target. In addition, a MATLAB GUI-based resolution analysis tool was developed to enhance the reliability of UAV image quality and the efficiency of the work. For this purpose, images were taken with an FC-6310 during flights at altitudes of 80 m, 120 m, and 150 m and by an iXM-100 at altitudes of 150 m, 200 m, and 400 m. The MTFs of UAV images were compared with traditional photogrammetry by measuring and analyzing MTFs on images taken by the UltraCAM Eagle Mark-2 sensor at a flight altitude of 1000 m. The results show that ${\sigma}MTF$ of the FC-6310 were 0.431(80 m), 0.524(120 m), and 0.699(150 m), and those of the iXM-100 were 0.332(150 m), 0.393(200 m), and 0.631(400 m), respectively. At the altitude of 150 m, the image quality of the iXM-100, which has a high-performance camera, was very high, and the effect of the camera performance on the image quality was confirmed. In addition, the ${\sigma}MTF$ of the UltraCAM Eagle Mark-2 was 0.711 due to the high flight altitude. This was the worst value among all UAV images. However, the ${\sigma}MTF$ of the FC-6310 at 150-m altitude was 0.699, which is almost the same as that of a manned aerial image.

• Biomedical Science Letters
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• v.10 no.2
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• pp.75-84
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• 2004

Massive identification of differentially expressed patterns has been used as a tool to detect genes that are involved in disease related process. We employed circular single stranded sense molecules as probe DNA for a DNA chip. The circular single stranded DNAs derived from 1,152 unigene cDNA clones were purified in a high throughput mode from the culture supernatant of bacterial transformants containing recombinant phagemids and arrayed onto silanized slide glasses. The DNA chip was examined for its utility in detection of differential expression profile by using cDNA hybridization. Hybridization of the single stranded probe DNA were performed with Cy3- or Cy5-labeled target cDNA preparations at $60^\circ$C. Dot scanning performed with the hybridized slide showed 29 up-regulated and 6 down-regulated genes in a cancerous liver tissue when compared to those of adjacent noncancerous liver tissue. These results indicate that the circular single stranded sense molecules can be employed as probe DNA of arrays in order to obtain a precious panel of differentially expressed genes.

• Geomechanics and Engineering
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• v.15 no.3
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• pp.879-888
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• 2018

Probability-based design codes have been developed to sufficiently confirm the safety level of structures. One of the most acceptable probability-based approaches is Load Resistance Factor Design (LRFD), which measures the safety level of the structures in terms of the reliability index. The main contribution of this paper is to calibrate the load and resistance factors of the design code for tunnels. The load and resistance factors are calculated using the available statistical models and probability-based procedures. The major steps include selection of representative structures, consideration of the limit state functions, calculation of reliability for the selected structures, selection of the target reliability index and calculation of load factors and resistance factors. The load and resistance models are reviewed. Statistical models of resistance (load carrying capacity) are summarized for strength limit state in bending, shear and compression. The reliability indices are calculated for several segments of a selected circular tunnel designed according to the tunnel manual report (Tunnel Manual). The novelty of this paper is the selection of the target reliability. In doing so, the uniform spectrum of reliability indices is proposed based on the probability paper. The final recommendation is proposed based on the closeness to the target reliability index.