• Journal of the Korean Society of Industry Convergence
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• v.9 no.4
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• pp.263-268
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• 2006

This paper presents a real-time verification system by extracting a features of multimodal biometrics using hybrid method, which is combined the moment balance and the independent component analysis(ICA). The moment balance is applied to reduce the computation loads by extracting the validity signal due to exclude the needless backgrounds of multimodal biometrics. ICA is also applied to increase the verification performance by removing the overlapping signals due to extract the statistically independent basis of signals. Multimodal biometrics are used both the faces and the fingerprints which are acquired by Web camera and acquisition device, respectively. The proposed system has been applied to the fusion problems of 48 faces and 48 fingerprints(24 persons * 2 scenes) of 320*240 pixels, respectively. The experimental results show that the proposed system has a superior verification performances(speed, rate).

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.3.1-3.1
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• 2011

Nanoengineered materials with advanced architectures are critical building blocks to modulate conventional material properties or amplify interface behavior for enhanced device performance. While several techniques exist for creating one dimensional heterostructures, electrospinning has emerged as a versatile, scalable, and cost-effective method to synthesize ultra-long nanofibers with controlled diameter (a few nanometres to several micrometres) and composition. In addition, different morphologies (e.g., nano-webs, beaded or smooth cylindrical fibers, and nanoribbons) and structures (e.g., core-.shell, hollow, branched, helical and porous structures) can be readily obtained by controlling different processing parameters. Although various nanofibers including polymers, carbon, ceramics and metals have been synthesized using direct electrospinning or through post-spinning processes, limited works were reported on the compound semiconducting nanofibers because of incompatibility of precursors. In this work, we combined electrospinning and galvanic displacement reaction to demonstrate cost-effective high throughput fabrication of ultra-long hollow semiconducting chalcogen and chalcogenide nanofibers. This procedure exploits electrospinning to fabricate ultra-long sacrificial nanofibers with controlled dimensions, morphology, and crystal structures, providing a large material database to tune electrode potentials, thereby imparting control over the composition and shape of the nanostructures that evolved during galvanic displacement reaction.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1394-1395
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• 2011

Now a days has problem of energy resource shortage and environmental pollution. We are looking up various solution plans regarding this problem. Solar power is one of the solution to solve the energy shortage problem. But solar power is affected by the weather. So variation weather we can use Maximum Power Point Tracing device for solar PV system. In this paper, New MPPT method is proposed to tracking MPP at low and high insolation by combining constant voltage method with Newton Method method.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.12
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• pp.3105-3114
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• 1993

previously, several basic studies in the experimental analysis of stress intensity factors of cracks by slab analogy have been presented by authors. But, for the application of above mentioned method to the analysis of the arbitrarily distributed cracks, there still is several bottlenecks to be overcome in terms of its experimental process and data treatment. Moreover, authors recently proposed an improved experimental method to use the fixed slab analogy device which has promised more accurate measurement of S.I.F. of small cracks. In this paper, for the completion of slab analogy analysis of distributed cracks, a grating imaginary rotation method is introduced. And, to prove its validity, this combined method is applied to the determination of stress intensity factors of theoretically known distributed cracks. The results show good agreement with the existing theoretical solutions and physical crack propagation tendencies.

• Journal of Korea Multimedia Society
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• v.16 no.11
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• pp.1338-1347
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• 2013

Face recognition is a science of automatically identifying individuals based their unique facial features. In order to avoid overfitting and reduce the computational reduce the computational burden, a new face recognition algorithm using PCA-fisher linear discriminant (PCA-FLD) and fuzzy radial basis function neural network (RBFNN) is proposed in this paper. First, face features are extracted by the principal component analysis (PCA) method. Then, the extracted features are further processed by the Fisher's linear discriminant technique to acquire lower-dimensional discriminant patterns, the processed features will be considered as the input of the fuzzy RBFNN. As a widely applied algorithm in fuzzy RBF neural network, BP learning algorithm has the low rate of convergence, therefore, an improved learning algorithm based on Levenberg-Marquart (L-M) for fuzzy RBF neural network is introduced in this paper, which combined the Gradient Descent algorithm with the Gauss-Newton algorithm. Experimental results on the ORL face database demonstrate that the proposed algorithm has satisfactory performance and high recognition rate.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.1
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• pp.59-63
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• 2000

For the Mo-tip field emitter array, the method by which the geometrical structure of the gate insulator wall could be modified in order to improve field emission properties(turn-on voltage and gate leakage current). The device having a gate insulator of complex shape, which means the combined geometrical structure with round shape made by wet etching and vertical shape made by dry etching processes, was fabricated and the field emission properties of the three kinds of devices were compared. As a result, the electric field applied to tip apex could be increased and gate leakage current could be decreased by employing the gate insulator having geometrical wall structure of mixed shape. Finally, the obtained empirical results were analyzed by simulation of electric field distribution at/near the tip apex and gate insulator using SNU-FEAT simulator.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.992-993
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• 2002

We have fabricated the diffractive optical head(DOH) for optical pick up, which one adaptable to a optical recoding information storage. DOH consists of a focusing grating coupler(FGC) and a solid immersion Jens(SIL). FGC is device that the light converge into a focus by surface lattice. FGC have been studied as a potential application of pick up head for the information storage. In this study, FGC was designed and fabricated to make focus near to possible diffraction limit. We also fabricated recording head combined with SIL. The focus was measured in the range of $1.1{\mu}m$ as near to possible diffraction limit in the FGC having a focusing length of $600{\mu}m$ and a lattice area of 500 * $500{\mu}m$.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.319-322
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• 1999

This paper presents a novel single-stage Power Factor Corrected(PFC) AC/DC forward converter with semi-automatic current shaping in order to achieve the unity power factor and an isolated output. Since the proposed circuit is combined a boost converter used for PFCs with a forward converter used for DC to DC conversion, the over-all size of system could be reduced. And thanks to the zero voltage switching(ZVS) in both switches, the voltage stress can be reduced considerably. A simple auxiliary circuit adopted into the secondary of transformer is composed of lossless components for reducing surge voltage. A prototype which has tow IGBT(Insulated Gate Bypolar Transistor) modules as switching device is manufactured to evaluate the proposed topology. The characteristics of the proposed circuit are tested, and the validity is verified by experimental results.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.10
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• pp.911-915
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• 2008

EL (electro-luminescent) device as a light source has an advantage in embodying large area with great flexibility. On nickel foil as an electrode and backplane, we demonstrated a white EL flexible light source with blue phosphor layer combined with color change layer. A correlation between color change layer and color coordination was analyzed by Gaussian method, and then the color coordinate was controlled near to (0.33, 0.33) of pure white light.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.350-353
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• 2009

The shielding enclosure is very essential device to test the electromagnetic wave power generated by various RF equipments. Some standards for the shielding enclosures were established to test them in right method. Generally, There are IEEE-STD-299 and MIL-STD-285 and NSA-65-6 of the method for measuring the effectiveness of shielding enclosures, the IEEE-STD-299 combined MIL-STD-285 and NSA-65-6 about the method for measuring shielding effectiveness(SE) about 1969 years, but, the measurement point of 299 proposal is many points(including shielding wall, seam, coner beat, shielding door, etc) and demand long time of measurement. To improve SE test method for shielding enclosures was studied and suggested to develop a proper test procedure. First, we measure reference level as frequency range and H/V polarization, secondly, measure leakage point, and finally, measure shield effect and calculate SE. Our method has a merit of the less measurement point than IEEE-STD-299, and shorten time than 299, and define representation SE of shielding enclosure effectively.