• Journal of Internet Computing and Services
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• v.8 no.6
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• pp.155-167
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• 2007

There are four types of human beings according to the Sasang Typology, Oriental medical doctors frequently prescribe healthcare information and treatment depending on one's type, The feature ratios (Table 1) on the human face are the most important criterions to decide which type a patient is. In this paper, we proposed a system to extract these feature ratios from the people's side face, There are two challenges in acquiring the feature ratio: one that selecting representative features; the other, that detecting region of interest from human profile facial image effectively and calculating the feature ratio accurately. In our system, an adaptive color model is used to separate human side face from background, and the method based on geometrical model is designed for region of interest detection. Then we present the error analysis caused by image variation in terms of image size and head pose, To verify the efficiency of the system proposed in this paper, several experiments are conducted using about 173 korean's left side facial photographs. Experiment results shows that the accuracy of our system is increased 17,99% after we combine the front face features with the side face features, instead of using the front face features only.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.9A
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• pp.767-775
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• 2011

In this paper, we propose a new multi-input multi-output (MIMO) channel modeling method for mobile-to-mobile (M2M) communications based on IEEE 802.16n. To reflect the mobilities at the transmitter and the receiver, we propose a new channel model by invoking the geometrical two-ring scattering model and modifying the conventional IEEE 802.16m fixed-to-mobile (F2M) channel model considering M2M communication environments. Through computer simulations, we analyze the statistical properties of proposed channel model in terms of the time correlation and the spatial correlation. Finally, the performance of the system using the proposed M2M channel model is compared with that using the conventional 802.16m F2M channel model by link level simulations.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.939-940
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• 2015

In this paper, a design method for a quasi-Yagi antenna (QYA) suitable for UHF band is studied. Due to the mutual coupling between a coplanar strip (CPS)-fed planar dipole and a conducting strip director placed close to the dipole, the dipole obtains broadband characteristics. A ground reflector improves gain in the lower frequency band, and the antenna size might be reduced by employing a bent reflector. The balun between the CPS line and the microstrip(MS) line is constructed by connecting the end of MS line and the CPS line through a shorting pin. In addition, a ring-type conductor connects the CPS line and reflector. The effects of various geometrical parameters and balun on the antenna characteristics are examined. An antenna, as an design example for the proposed antenna, is designed for the operation in the frequency band of 470-806 MHz for terrestrial DTV.

• Korean Journal of Optics and Photonics
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• v.17 no.6
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• pp.532-536
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• 2006

The position of stereoscopic objects is an important parameter to induce three-dimensional effects such as convergence control and image distortions. There are three kinds of stereoscopic cameras : Parallel, Toed-in, and Horizontal-Moving cameras. In this paper we proposed the method for estimating stereoscopic object position with a horizontal-moving camera. In the previous methods, viewing angle ratios are used to estimate the object positions. Our method based on the horizontal movements of the camera to estimate the positions. Using geometrical models of shooting and display we experimented with two methods. Results of experiments showed the distance of stereoscopic objects on virtual screen related to horizontal movement.

• Journal of the Korea Society of Computer and Information
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• v.13 no.1
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• pp.89-97
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• 2008

In this paper, we present a method for the enhancement of marker detection correctness and marker recognition speed by using artificial neural network. Contours of objects are extracted from the input image. They are approximated to a list of line segments. Quadrangles are found with the geometrical features of the approximated line segments. They are normalized into exact squares by using the warping technique and scale transformation. Feature vectors are extracted from the square image by using principal component analysis. Artincial neural network is used to checks if the square image is a marker image or a non-marker image. After that, the type of marker is recognized by using an artificial neural network. Experimental results show that the proposed method enhances the correctness of the marker detection and recognition.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.1
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• pp.155-161
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• 2007

This paper presents the design simulation, implementation, and measurement of a miniaturized PCS / Satellite DMB dual-band stacked mompole antenna with a parasitic patch for mobile communication terminals. A stacked helix is realized by using a via hole with height of 0.4 mm and a diameter of 0.35 mm to connect upper- and lower-layer helix sections for a reduction of the dimensions of the antenna. In addition the stacked helix chip antenna is interleaved with a parasitic patch to achieve two different radiation modes. The ratio of the first frequency and the second frequency vary with the geometrical parameter of the parasitic patch. The fabricated antenna uses FR-4 substrate with a relative permittivity of 4.2. Its dimensions are $15.5{\times}7.6{\times}0.4 mm^3$. The measured impedance bandwidths (VSWR<2) are 240 and 250 MHz at the operating frequencies, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.2A
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• pp.70-79
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• 2003

A theoretical presentation of evanescent coupling is offered with respect to the refractive indexes between a side polished optical fiber and an infinitely planar waveguide with a conductor cladding(PWGCC). The PWG is suspended at a constant distance from an unclad fiber core and attached with the perfect conductor(PEC) on one side. The behavior of the distributed coupler is examined using a coupled mode model, which takes account of the two dimensions of the waveguide configuration. The coupling and propagation of light were found to depend on both the relationship between the refractive index values of each structure and the configuration of the side polished fiber used in the PWGCC. The spreading of light in the unconfined direction of the PWGCC is described in terms of a simple geometrical interpretation of the synchromization condition that is in agreement with a previous investigation of the problem based on the coupled-mode theory(CMT). The power of the light propagation in the fiber decreased exponentially along the fiber axis as it was transferred to the PWGCC.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.12
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• pp.103-110
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• 2005

The performance of maximum likelihood(ML) detection for the given channel is analyzed in spatially multiplexed MIMO system. In order to obtain the vector symbol error rate, we define error vectors which represent the geometrical relation between lattice points. The properties of error vectors are analyzed to show that all lattice points in infinite lattice almost surely have four nearest neighbors after random channel transformation. Using this information and minimum distance obtained by the modified sphere decoding algorithm, we formulate the analytical performance of vector symbol error over the given channel. To verify the result, we simulate ML performance over various random channel which are classified into three categories: unitary channel, dense channel, and sparse channel. From the simulation results, it is verified that the derived analytical result gives a good approximation about the performance of ML detector over the all random MIMO channels.

• International Journal of Fluid Machinery and Systems
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• v.9 no.4
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• pp.338-353
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• 2016

Information on the surge behaviors and stall stagnation boundaries for a nine-stage axial flow compressor are summarized on the basis of analytical data in comparison with those for a single-stage one, with attention to the pressure ratio effect. The general trends of the surge loop behaviors of the pressure-mass flow are similar for both compressors including the fact that the subharmonic surges tend to appear very near the stall stagnation boundaries. With respect to the nine-stage compressor, however, the mild loops in the subharmonic surges tend to be very small in size relative to the deep loops, and at the same time, insufficient surge recovery phenomenon, which is a kind of subharmonic surge, appears also far from the stagnation boundary for relatively short delivery flow-paths. The latter is found to be a rear-stage surge caused by unstalling and re-stalling of the rear stages with the front-stages kept in stall in the stalled condition of the whole compressor, which situation is caused by stage-wise mismatching in the bottom pressure levels of the in-stall multi-stage compressor. The fundamental information on the stall stagnation boundaries is given by a group of normalized geometrical parameters including relative delivery flow-path length, relative suction flow-path length, and sectional area-pressure ratio, and by another group of normalized frequency parameters including relative surge frequencies, modified reduced resonance frequencies, and modified reduced surge frequencies. Respective groups of the normalized parameters show very similar tendency of behaviors for the nine-stage compressor and the single-stage compressor. The modified reduced resonance frequency could be the more reasonable parameter suggesting the flow-induced oscillation nature of the surge phenomena. It could give the stall stagnation boundary in a more unified manner than the Greitzer's B parameter.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.2C
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• pp.16-24
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• 2005

In this paper, we proposed a face tracking algorithm for a viewpoint adaptive multi-view synthesis system. The original scene captured by a depth camera contains a texture image and 8 bit gray-scale depth map. From this original image, multi-view images can be synthesized which correspond to viewer's position by using geometrical transformation such as a rotation and a translation. The proposed face tracking technique gives a motion parallax cue by different viewpoints and view angles. In the proposed algorithm, tracking of viewer's dominant face initially established from camera by using statistical characteristics of face colors and deformable templates is done. As a result, we can provide motion parallax cue by detecting viewer's dominant face area and tracking it even under a heterogeneous background and can successfully display the synthesized sequences.