• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.8
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• pp.843-850
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• 2012

To satisfy the operational requirements of surveillance radar and the operational concept of a ship combat system, an active-array-type antenna was designed using solid-state transmitters and receivers. The arrangement of the constituent electronic components of the antenna system, considerably large in size, and therefore, the antenna needs to be housed in a box. The rotational antenna system installed on a ship mast is installed in a sealed housing to protect the interior equipment from environmental conditions. The outer shape of the housing is that the antenna should be capable of rotating normally despite strong winds. Furthermore, in recent times, designs with low radar cross section (RCS) have attracted attention from the viewpoint of improving the stealth of the ship. In this light, four types of models are proposed for the outer shape design of the antenna system, and they are investigated from the viewpoint of low RCS design as well as wind load.

• The KIPS Transactions:PartB
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• v.16B no.4
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• pp.299-308
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• 2009

AAM(Active Appearance Model) is an algorithm to extract face feature points with statistical models of shape and texture information based on PCA(Principal Component Analysis). This method is widely used for face recognition, face modeling and expression recognition. However, the detection performance of AAM algorithm is sensitive to initial value and the AAM method has the problem that detection error is increased when an input image is quite different from training data. Especially, the algorithm shows high accuracy in case of closed lips but the detection error is increased in case of opened lips and deformed lips according to the facial expression of user. To solve these problems, we propose the improved AAM algorithm using lip feature points which is extracted based on a new lip detection algorithm. In this paper, we select a searching region based on the face feature points which are detected by AAM algorithm. And lip corner points are extracted by using Canny edge detection and histogram projection method in the selected searching region. Then, lip region is accurately detected by combining color and edge information of lip in the searching region which is adjusted based on the position of the detected lip corners. Based on that, the accuracy and processing speed of lip detection are improved. Experimental results showed that the RMS(Root Mean Square) error of the proposed method was reduced as much as 4.21 pixels compared to that only using AAM algorithm.

• Smart Media Journal
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• v.12 no.10
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• pp.93-101
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• 2023

Climate change has emerged as a global problem, with frequent temperature increases, droughts, and floods, and it is predicted that it will have a great impact on the characteristics and productivity of crops. Cnidium officinale is used not only as traditionally used herbal medicines, but also as various industrial raw materials such as health functional foods, natural medicines, and living materials, but productivity is decreasing due to threats such as continuous crop damage and climate change. Therefore, this paper proposes a model that can predict the physiologically active ingredient index according to the climate change scenario of Cnidium officinale, a representative medicinal crop vulnerable to climate change. In this paper, data was first augmented using the CTGAN algorithm to solve the problem of data imbalance in the collection of environment information, physiological reactions, and physiological active ingredient information. Column Shape and Column Pair Trends were used to measure augmented data quality, and overall quality of 88% was achieved on average. In addition, five models RF, SVR, XGBoost, AdaBoost, and LightBGM were used to predict phenol and flavonoid content by dividing them into ground and underground using augmented data. As a result of model evaluation, the XGBoost model showed the best performance in predicting the physiological active ingredients of the sacrum, and it was confirmed to be about twice as accurate as the SVR model.

• The Korean Journal of Financial Management
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• v.25 no.2
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• pp.1-31
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• 2008

Before the financial crisis in 1997, Korean bond markets had been those of corporate bonds with relatively high market yield. During the period, most of major institutional investors tend to utilize passive strategies such as buying and holding. After the crisis, however, they could not help choosing active bond management strategies because of lowed yield level and intensified competition among the financial institutions. This study is forced on the yield curve, which is the reflection of all information on the bond investment environments. The study also make analysis on the major economic and securities market factors and its structural relationship with the shape of the curve such as level, curvature and slope. For these purposes, an empirical model based on the Nelson-Siegel Model is estimated with the data during $1999{\sim}2006$. Out-of-sample forecasting is also made to test the usefulness of the estimated model. In addition, the dependent variables which are the estimates of level and slope are estimated on the macro variables and securities market variables. VAR and SUR models are used for the estimation. Estimation results show that level and slope of the yield curve are influenced by the target call rate change, exchange rate change rate, inflation rate. These results provide practical implications for the active managements in the overall treasury bond markets.

• Smart Structures and Systems
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• v.6 no.1
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• pp.39-56
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• 2010

Structural Control relies, with a great deal, on the ability of the control algorithm to identify the current state of the system, at any given point in time. When such algorithms are designed to perform in a smart manner, several smart technologies/devices are called upon to perform tasks that involve pattern recognition and control. Smart pattern recognition is proposed to replace/enhance traditional state identification techniques, which require the extensive manipulation of intricate mathematical equations. Smart pattern recognition techniques attempt to emulate the behavior of the human brain when performing abstract pattern identification. Since these techniques are largely heuristic in nature, it is reasonable to ensure their reliability under real life situations. In this paper, a neural network pattern recognition scheme is explored. The pattern identification of three structural systems is considered. The first is a single bay three-story frame. Both the second and the third models are variations on benchmark problems, previously published for control strategy evaluation purposes. A Neural Network was developed and trained to identify the deformed shape of structural systems under earthquake excitation. The network was trained, for each individual model system, then tested under the effect of a different set of earthquake records. The proposed smart pattern identification scheme is considered an integral component of a Smart Structural System. The Reliability assessment of such component represents an important stage in the evaluation of an overall reliability measure of Smart Structural Systems. Several studies are currently underway aiming at the identification of a reliability measure for such smart pattern recognition technique.

• Journal of The Geomorphological Association of Korea
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• v.24 no.1
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• pp.39-50
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• 2017

This study was conducted to analyze the variation of hydro-geomorphological environment along Baekgok wetland, which experiencing periodical inundation, in that water-level fluctuation of reservoir caused by irrigation. Since the field data is unavailable, modeling techniques, involving models such as HSPF and TELEMAC-2D, have been applied to simulate hydrological cycle in watershed and hydrodynamics in channel scale. The result of simulation indicates that the water-level of reservoir determines both the water surface extension and water depth in the wetland. Furthermore, it also shows that water-level functions as a spatial limit factor for a fluvial environment and woody vegetation such as willow. The fact of which the scale of water-level fluctuation being larger than an average topographical relief along the wetland can explain the result. While the water-level kept high, the wetland is submerged and waterbody becomes lentic. In contrast, while the water-level is lowered, fluvial phenomena of which being dependent on flow rate and channel shape become active. Hence, the valid fluvial process is likely to take place only for 4 months annually just near the channel, and it advances to a conclusion expecting a deposition to be dominant among the wetland except for such area. It is anticipated that such understanding can contribute to establishing plans to preserve the geomorphological and ecological value of the Baekgok wetland.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.70.3-70.3
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• 2016

Active galactic nuclei (AGNs) typically show a non-thermal continuum locally represented by a power-law and many prominent emission lines in the UV and optical regions. AGNs are classified by two types, where Type I AGNs exhibit both broad and narrow lines and only narrow lines are observed in Type 2 AGNs. The unification models of AGNs invoke the existence of a molecular torus just outside of the broad line region. In the presence of a high column HI region associated with the molecular torus, we propose that significant fraction of broad line photons near Lyman series can be scattered by atomic hydrogen in the torus. In particular, $Ly{\alpha}$ being the strongest emission line, strong linear polarization may develop around $Ly{\alpha}$ through Rayleigh scattering. We adopt a Monte Carlo technique to investigate the polarized transfer of $Ly{\alpha}$ in a thick HI region with the shape of a torus. We consider the range of HI column density N_HI = 1020-23 with fixed geometric parameters of the torus such as the inner and outer radii and the height. We present the polarized spectra and angular distribution of Rayleigh scattered radiation around $Ly{\alpha}$. We find that the $Ly{\alpha}$ core part is polarized in the direction perpendicular to the symmetry axis whereas in the far wing part it is polarized in the parallel direction. It is concluded that the unification of AGNs implies that $Ly{\alpha}$ can be uniquely polarized through Rayleigh scattering.

• Proceedings of the Korean Society of Food Science and Nutrition Conference
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• 2004.11a
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• pp.110-115
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• 2004

The immature fruits of Poncirus trifoliata L. or Ponciri fructus (PF), well known as 'Jisil' in Korea, have been used against allergic diseases for generations, and still occupy an important place in traditional Oriental medicine. Anti-allergic effects of this fruit have been investigated in a few experimental models. Immunoglobulin E (IgE) is the principal immunoglobulin involved in immediate hypersensitivities and chronic allergic diseases. The effect of an aqueous extract of PF on in vivo and in vitro IgE production was investigated. PF dose-dependently inhibited the active systemic anaphylaxis and serum IgE production induced by immunization with ovalbumin, Bordetelia pertussis toxin and aluminum hydroxide gel. PF strongly inhibited interleukin 4 (IL-4)-dependent IgE production by lipopolysaccharide-stimulated murine whole spleen cells. In the case of U266 human IgE-bearing B cells, Ponciri fructus also showed an inhibitory effect on the IgE production. On the other hand, mast cell hyperplasia can be causally related with chronic inflammation. Stem cell factor (SCF), the ligand of the c-kit protooncogene product, is a major regulator and ohernoattractant of mast cells. Ponciri fiuctus (1 mg/mL) significantly inhibited the SCF-induced migration of rat peritoneal mast cells (RPMCs). RPMCs exposed to SCF (50 ng/mL) resulted in a drastic shape change with a polarized morphology while the cells exposed to Ponciri fructus (1 mg/mL) remained resting, with little or no shape alteration. The drastic morphological alteration and distribution of polymerized actin were blocked by pretreatment with Ponciri fructus. In addition, Ponciri fructus inhibited both TNF-alpha and IL-6 secretion from RPMCs stimulated with SCF. These results suggest that Ponciri fructus has an anti-allergic activity by inhibition of IgE production from B cells. These findings also provide evidence that Ponciri fructu inhibits chemotactic response and inflammatory cytokines secretion to SCF in mast cells.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.48.1-48.1
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• 2012

We present the ultraviolet (UV) color-color relation of early-type galaxies (ETGs) in the nearby universe (0.05 < z < 0.12) to investigate the properties of hot stellar populations responsible for the UV excess (UVX). The initial sample of ETGs is selected by the spectroscopic redshift and the morphology parameter from the SDSS DR 7, and then cross-matched with the GALEX far-UV (FUV) and near-UV (NUV) GR6 data. The cross-matched ETG sample is further classified by their emission line characteristics in the optical spectra into quiescent, star-forming, and active galactic nucleus categories. Contaminations from early-type spiral galaxies, mergers, and morphologically disturbed galaxies are removed by visual inspection. By drawing the FUV-NUV (as a measure of UV spectral shape) versus FUV-r (as a measure of UVX strength) diagram for the final sample of -3700 quiescent ETGs, we find that the "old and dead" ETGs consist of a well-defined sequence in UV colors, the "UV red sequence," so that the stronger UVX galaxies should have a harder UV spectral shape systematically. However, the observed UV spectral slope is too steep to be reproduced by the canonical stellar population models in which the UV flux is mainly controlled by age or metallicity parameters. Moreover, 2 mag of color spreads both in FUV-NUV and FUV-r appear to be ubiquitous among any subsets in distance or luminosity. This implies that the UVX in ETGs could be driven by yet another parameter which might be even more influential than age or metallicity.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.6
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• pp.1911-1918
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• 2014

The increase of input resources, such as labor and equipment, in a construction project causes workspace interference between activities and it influences on the productivity and quality of construction activities. To solve this problem, many studies related to the workspace interference have been performed, however they verified the workspace concerning with only the geometric location of activities or generated the shape of workspace by a whole object concept not separated units of detailed operations. It is difficult for project manager to reasonably analyze the workspace conflict, because the size of workspace cannot reflect the characteristics of an activity and input time of a resource. This paper presents a methodology that can generate three-dimensional models in order to optimize the workspace shape and size by considering with the characteristics of each activity and input time of each resource. The suggested method can be used for the active BIM system that optimizes the workspace conflict without additional construction duration and for the searching algorithm of optimized moving path for construction equipment.