• Transactions of Materials Processing
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• v.7 no.3
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• pp.233-245
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• 1998

A new approach has been proposed for the incremental analysis of the nonsteady state large deformation of planar anisotropic elastic-plastic sheet forming. A mathematical brief review of a constitutive law for the incremental deformation theory has been presented from flow theory using the minimum plastic work path for elastic-plastic material. Since the material embedded coordinate system(Lagrangian quantity) is used in the proposed theory the stress integration procedure is completely objective. A new return mapping algorithm has been also developed from the general midpoint rule so as to achieve numerically large strain increment by successive control of yield function residuals. Some numerical tests for the return mapping algorithm were performed using Barlat's six component anisotropic stress potential. Performance of the proposed algorithm was shown to be good and stable for a large strain increment, For planar anisotropic sheet forming updating algorithm of planar anisotropic axes has been newly proposed. In order to show the effectiveness and validity of the present formulation earing simulation for a cylindrical cup drawing and front fender stamping analysis are performed. From the results it has been shown that the present formulation can provide a good basis for analysis for analysis of elastic-plastic sheet metal forming processes.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.4
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• pp.619-626
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• 2000

The electromagnetic fields of the corrugated annular feed-horn antenna have been analyzed exactly by using the finite-difference time-domain (FDTD) technique. The radiation pattern and return loss characteristics of the antenna were obtained as a function of the impedance of feeding coaxial line at 11.8GHz. The return loss was determined to be less than -25dB at 30$\Omega$. It was confirmed that the phase error is less compared to that of the antenna without corrugation, but the directivity of the radiation pattern needs to be improved.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.571-575
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• 2010

Drought is a natural hazard with different properties that are usually dependent to each other. Therefore, a multivariate model is often used for drought frequency analysis. The Copula based bivariate drought severity and duration frequency analysis is applied in the current study in order to show the effect of tail behavior of drought severity and duration on the selection of a copula function for drought bivariate frequency analysis. Four copula functions, namely Clayton, Gumbel, Frank and Gaussian, were fitted to drought data of four stations in Iran and Canada in different climate regions. The drought data are calculated based on standardized precipitation index time series. The performance of different copula functions is evaluated by estimating drought bivariate return periods in two cases, [$D{\geq}d$ and $S{\geq}s$] and [$D{\geq}d$ or $S{\geq}s$]. The bivariate return period analysis indicates the behavior of the tail of the copula functions on the selection of the best bivariate model for drought analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.9
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• pp.1999-2005
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• 2015

A wind velocity is measured in a weather radar as well as the strength of return echoes from rain clouds. These wind velocities are obtained through estimation of Doppler frequencies in return signals. This kind of Doppler frequency estimation method is called as a correlation method. It is widely used in most weather radars because of less computation time. However, it may cause serious errors if a spectrum is not symmetric. Therefore, in this paper, it is shown that the improved method using 3^rd order phase estimation model yields the more accurate estimation of the average Doppler frequency using various simulated weather data.

• Journal of electromagnetic engineering and science
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• v.10 no.1
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• pp.39-44
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• 2010

In this paper, a compact wideband antenna with a band-notch function is proposed. It operates over the UWB band with a band-stop characteristic. To increase the impedance bandwidth, a ring-shaped radiator is used. By attaching a circular stub to the ring-shaped radiator, the band-notch performance is obtained. The proposed antenna operates over a frequency range from 2.7 GHz to 11 GHz to satisfy the 10-dB return-loss requirement and provides band-stop performance in the frequency band from 5.15 GHz to 6.1 GHz. Experimental results reveal that the proposed antenna exhibits good radiation performance and is suitable for UWB applications.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.2
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• pp.278-283
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• 2008

As the usefulness of internet is kept changing more productively with web 1.0, web 2.0 usage of XML is also increasing very rapidly. In XML environment the most critical function is the ability of effective retrieval of useful information from XML repository. That makes the W3C XQuery more popular XQuery has very complicated structure as a query language due to the semi_structured nature of XML. FLOWOR, which stand for, let. where, order by, return, is the most commonly used expression in XQuery. In this paper we suggest the methods to handle XQuery FLWOR on relational environments. We also analyze and evaluate our approach to prove its correctness.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1982.05a
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• pp.7.3-7
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• 1982

Endotracheal intubation is common practice for either general anesthesia or keeping artificial airway in various conditions. Despite of its great usefulness, however, laryngeal edema, ulceration, and granuloma are occasionally developed following endotracheal intubation as posttraumatic complications. Vocal cord paralysis is also rarely developed. Recently we experienced a case of left vocal cord paralysis with accompanying hoarseness following endotracheal general anesthesia for appendectomy. The symptoms of hoarseness and sore throat developed immediately after the general anesthesia. Periodic check revealed gradual return to normal function of the paralyzed cord with the complete function about 3 months after the anesthesia.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.4
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• pp.441-448
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• 2012

This paper describes the optimal home positioning algorithm of Eclipse-II, a new conceptual parallel mechanism for motion simulator. Eclipse-II is capable of translation and 360 degrees continuous rotation in all directions. In unexpected situations such as emergency stop, riders have to be resituated as soon as possible through a shortest translational and rotational path because the return paths are not unique in view of inverse kinematic solution. Eclipse-II is man riding. Therefore, the home positioning is directly related to the safety of riders. To ensure a least elapsed time, ZYX Euler angle inverse kinematics is applied to find an optimal home orientation. In addition, the subsequent decrease of maximum acceleration and jerk values is achieved by combining the optimal return path function with cubic spline, which consequently reduces delivery force and vibration to riders.

• Nuclear Engineering and Technology
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• v.51 no.2
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• pp.607-617
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• 2019

Global warming and climate change are increasing the intensity of typhoons and hurricanes and thus increasing the risk effects of typhoon and hurricane hazards on nuclear power plants (NPPs). To reflect these changes, a new NPP should be designed to endure design-basis hurricane wind speeds corresponding to an exceedance frequency of $10^{-7}/yr$. However, the short typhoon and hurricane observation records and uncertainties included in the inputs for an estimation cause significant uncertainty in the estimated wind speeds for return periods of longer than 100,000 years. A logic-tree framework is introduced to handle the epistemic uncertainty when estimating wind speeds. Three key parameters of a typhoon wind field model, i.e., the central pressure difference, pressure profile parameter, and radius to maximum wind, are used for constructing logic tree branches. The wind speeds of the simulated typhoons and the probable maximum wind speeds are estimated using Monte Carlo simulations, and wind hazard curves are derived as a function of the annual exceedance probability or return period. A logic tree decreases the epistemic uncertainty included in the wind intensity models and provides reasonably acceptable wind speeds.

• Korean Journal of Construction Engineering and Management
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• v.5 no.3 s.19
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• pp.88-96
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• 2004

Recently, client requirements concept is an important issue related to many effects of firms. Especially, if we think that apartment is given a great deal of national construction industry, it is requested that we should try to improve apartment quality with various methods of client requirements survey and reflecting those on apartment project. The technique searching and applying client requirements to apartment project is requested for that and ROQ(Return On Quality) process connected to QFD(Quality Function Deployment) is a technique which is used in manufacturing industry and help to make money by rising client satisfaction with searching clients requirements, and applying this to quality improvement program. In this study apartment quality management development is suggested through using ROQ process. For this customer interview research and FGI(Focus Group Interview) was carried out and clients requirement was analyzed with this. Then quality improvement program applicable to developing a new apartment product was established with specialist monitoring. A new apartment quality management development plan is prosed with this process.