• Communications of the Korean Mathematical Society
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• v.21 no.3
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• pp.577-586
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• 2006

In this paper we will propose the methods for finding the non-invertible ideals corresponding to non-primitive quadratic forms and clarify the structures of class SEMIGROUPS of imaginary quadratic orders which were given by Zanardo and Zannier [8], and we will give a general algorithm for calculating power of ideals/classes via the Dirichlet composition of quadratic forms which is applicable to cryptography in the class semigroup of imaginary quadratic non-maximal order and revisit the cryptosystem of Kim and Moon [5] using a Zanardo and Zannier [8]'s quantity as their secret key, in order to analyze Jacobson [7]'s revised cryptosystem based on the class semigroup which is an alternative of Kim and Moon [5]'s.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.303-307
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• 2002

Although Synthetic Aperture Radar(SAR) is a very powerful and attractive tool, automatic interpretation of SAR images is extremely difficult because of several reason. Spatially, speckle noise reduction in SAR images is important step to interpret the SAR image at the preprocessing step. The speckle noise in SAR images is modeled to be multiplicative, and therefore, a signal-dependent noise. So, it has deflated many image-denoising algorithms that are based on additive noise model. In this paper, we propose an adaptive wavelet shrinkage method for speckle noise reduction in SAR images by analyzing the high frequency level in detail. We first decompose minutely the high frequency level to analyze the noise level. And then, we determine the weighting threshold value per the level, and layer. Finally, using those weighting threshold, we produce the efficient wavelet shrinkage method. So, this method not only reduces the speckle noise, but also preserves image detail and sharpness.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1752-1758
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• 2006

Racing game requires plausible physics model that can be simulated in realtime. Minor artifacts in racing games are easily noticed, and any kinds of games should work interactively. It is difficult to model the accurate tire-ground physics and to integrate the model into realtime environments. In this paper, an efficient and effective 'imaginary wall' model was proposed. The method can be easily implemented because of the simplicity of the physical model used, and the result of the simulation is realistic enough for the racing games.

• Korean Institute of Interior Design Journal
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• no.19
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• pp.69-75
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• 1999

In a modern mass society, a theme park satisfies a consumer's desire of being meaningful in such an imaginary space, which is far beyond the real life. The introductory area of the theme park is a boundary between th real and the imaginary spaces and a fundamental spac of realizing the introductory imaginary space. The objective of this study is to suggest an appropriate method of design application by analyzing the characteristics of the theme park with an example, a theoretical background is first presented by examining the characteristics of the introductory are of the theme park. Than, as an example that reflects well its characteristics, 'Global fair' of the Everland is selected and analyzed based on the developed theoretical background.

• Journal of the Korean Society of Systems Engineering
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• v.5 no.1
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• pp.57-65
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• 2009

The purpose of Defense Acquisition Project is that the superior weapons validated needs and performance are supplied to military user with limited financial resources and time. The Warship Acquisition Project is not only like this, But also has special characteristics of long project period and first-constructed ship's operation employment. So, The Warship Acquisition Project need systematic and efficient procedure & management. And this paper researches System engineering application of imaginary WIG(Wing-In-Ground Effect) ship acquisition project based Systems Engineering Handbook ver.3.1 published by INCOSE, the lead of field. The Imaginary WIG(Wing-In-Ground Effect) ship acquisition project applied the four processes(technical project, Enterprise & Agreement, Enabling Systems), the basis of INCOSE Engineering Handbook ver.3.1, and the each process output compared with DAPA(Defense Acquisition Program Administration)'s warship acquisition procedure.

• Journal of Electrical Engineering and Technology
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• v.3 no.1
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• pp.94-100
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• 2008

This paper presents a new control method of single-phase active power filter (APF) for the compensation of harmonic current components in nonlinear loads. To facilitate the possibility of complex calculation for harmonic current detection of the single phase, a single-phase system that has two phases was constructed by including an imaginary second-phase giving time delay to the load current. The imaginary phase, which lagged the load current T/4 (Here T is the fundamental cycle) is used in the conventional method. But in this proposed method, the new signal as the second phase is delayed by the filter. Because this control method is applied to a single-phase system, an instantaneous calculation was developed by using the rotating reference frames synchronized to source-frequency rather than by applying instantaneous reactive power theory that uses the conventional fixed reference frames. The control scheme of single-phase APF for the current source with R-L loads is applied to a laboratory prototype to verify the proposed control method.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.20-23
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• 1994

It is well known that the Boyd's theorem states the relation between the imaginary eigenvalues of discriminant H of Riccati equation (A, R, Q) and the singular value of transfer function, but it is only available for R .geq. 0 and Q .geq. 0. In this paper, we extend Boyd's theorem for two case, that is, R is symmetric, Q is sign definite, and R is sign definite, Q is symmetric. We give under the condition that there is a real symmetric solution of Riccati equation the relation between H has imaginary eigenvalue and the maximum eigenvalue of transfer functoin. Finally, we give a necessary and sufficient condition to determine whether H has imaginary eigenvalue under some conditions.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.3
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• pp.545-551
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• 2012

In this paper, we propose a new cryptosystem based on the IQC depended on the complexity of class number and intractibility of factoring integer, and introduce two algorithm which reduce encryption and decryption times. To recognize the security of the cryptosystem, we take a simple example to analyze the complexities of public key and secret key and then introduce the operating process of the cryptosystem.

• English Language & Literature Teaching
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• v.13 no.4
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• pp.193-210
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• 2007

This essay is an attempt to give a theoretical articulation of novelistic mimesis as the narrative form of modernity. With the passage to modernity, what assumes the locus of the symbolic authority is no longer God, Father, or tradition, but the cultural gaze or the ego-ideal. At the same time, this gaze paradoxically coalesces with the "spectacle of the world," on the side of the reified "other": the gaze is both the desexualized ego-ideal and its instantaneous transmogrification and resexualization in the opaque world of objects. The imaginary ego or the eye on the side of the subject of representation is held at abeyance in a state of perpetual fascination and desperation in relation to the gaze as the world of "others," which lies always at one remove from the purview of the imaginary ego. This understanding of the inadequation of the ego to the cultural gaze of the reified world provides a critical fulcrum upon which I base my theory of the modern narrative mimesis as the "perverse" field of spatial arrangement, in which the split of the subjectivity into the imaginary ego and the ego-ideal is suspended over the phantasmatic world of bodies and territories.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.7
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• pp.196-202
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• 2000

In the precision point synthesis of mechanisms, it is usually required to solve a system of polynomial equations. With the aid of efficient algorithms such as elimination, it is possible to obtain all the solutions of the equations in the complex domain. But among these solutions only real values can be used fur real mechanisms, while imaginary ones are liable to be discarded. In this article, a method is presented, which leads the imaginary solutions to real domain permitting slight alteration of prescribed positions and eventually increases the number of feasible mechanisms satisfying the desired motion approximately. Two synthesis problems of planar 4-bar path generation and spatial 7-bar motion generation are given to verify the proposed method.