• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.3
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• pp.26-31
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• 1999

In this paper, we propose a facial characteristic detection algorithm based on knowledge and object segmentation method for image communication. In this algorithm, under the condition of the same lumination and distance from the fixed video camera to human face, we capture input images of 256 $\times$ 256 of gray scale 256 level and then remove the noise using the Gaussian filter. Two images are captured with a video camera, One contains the human face; the other contains only background region without including a face. And then we get a differential image between two images. After removing noise of the differential image by eroding End dilating, divide background image into a facial image. We separate eyes, ears, a nose and a mouth after searching the edge component in the facial image. From simulation results, we have verified the efficiency of the Proposed algorithm.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.5 s.347
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• pp.162-168
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• 2006

Understanding of propagation characteristics is very important for the wireless communication system design and wireless communication service construction. In this paper, propagation characteristics is measured and analyzed at 2.45Ghz frequency band under curved subway tunnel environment. We constituted channel measurement system with sliding correlation and five different kind of antennas. The purpose of five different type of antennas is to compare propagation characteristics according to beam shape of antennas. The path loss under tunnel environment is average $4.38^{\sim}14.41dB$ lower than free space and circular polarization antenna marked smallest path loss. Also, path loss is smallest when the receiver antenna located outside of tunnel in th curved section. 90% of delay components of all antennas measured within 20ns and directional antenna has more wide coherence bandwidth than omni-directional antenna. According to measured result, when we consider path loss and delay characteristics, circular polarization antenna is most suitable under tunnel environment.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.8
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• pp.119-126
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• 2016

In this paper, we proposed the planar textile resonator for constructing wearable MR-WPT system and analyzed the characteristic of textile substrates used in resonators. The planar textile resonators were designed to resonate at 1-10 MHz. The loop and coil were fabricated planar structure on textile substrate using conductive materials. Polyester fiber and cotton widely used in real life were chosen as textile resonators for wearable applications and copper tape and silver paste were used for fabricating planar loop and coil on textile substrate. For comparison analysis on transfer efficiency according to the types of textile, transmitter and receiver parts were symmetric. According to the result, for the highest transfer efficiency of wearable WPT system, the planar resonators have specifications of relative thick textile substrate with low permittivity and low surface resistance of conductive pattern. The performed experiments show that the planar textile resonator is possible to be used for resonator in wearable MR-WPT system.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.3
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• pp.54-60
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• 2010

The local appearance-based method is one of the face recognition methods that divides face image into small areas and extracts features from each area of face image using statistical analysis. It collects classification results of each area and decides identity of a face image using a voting scheme by integrating classification results of each area of a face image. The conventional local appearance-based method divides face images into small pieces and uses all the pieces in recognition process. In this paper, we propose a local appearance-based method that makes use of only the relatively important facial components. The proposed method detects the facial components such as eyes, nose and mouth that differs much from person to person. In doing so, the proposed method detects exact locations of facial components using support vector machines (SVM). Based on the detected facial components, a number of small images that contain the facial parts are constructed. Then it extracts features from each facial component image using principal components analysis (PCA). We compared the performance of the proposed method to those of the conventional methods. The results show that the proposed method outperforms the conventional local appearance-based method while preserving the advantages of the conventional local appearance-based method.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.4
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• pp.356-363
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• 2003

An eddy current testing system was developed for detection of flaws in the ferromagnetic steel tubes. Because the eddy current signals from the ferromagnetic steel tubes could be distorted easily due to an irregularity of magnetic permeability, magnetic saturation is required to suppress this variation of magnetic fields. A magnetic saturation probe with the Hemholtz coil was designed for the inspection of the steel tubes. The bandwidth pass filters were adapted to minimize the noise from the DC magnetization. When using the designed test probe, the flaw signals could be discriminated from the noise. The system was tested at the production line and showed a capability of detecting flaws, like a drilled hole of the diameter of 2.0mm at the moving speed of 1m/sec.

• Journal of the Korean Vacuum Society
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• v.18 no.3
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• pp.176-185
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• 2009

The realization and the performance of ICP source are strongly affected by its electrical impedance and the electric/magnetic field distribution. The ICP source impedance is determined by the antenna impedance and the plasma one. It is preferred to keep the imaginary impedance between -100 ohm to 100 ohm, since it should be avoided the high voltage formation on the antenna and abrupt impedance variation during the thin film process. The plasma uniformity is affected by the electric and magnetic field which is formed by the antenna current and voltage. The influence of azimuthal symmetry are shown by the electromagnetic simulation and the measurement result of plasma density. The radial uniformity can be controlled by locating the concentric antennas which have different diameters. The power distribution ratio and its control method are presented in the case of parallel antenna connections.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.2
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• pp.137-144
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• 2011

A Simple equivalent circuit model is developed for a wireless energy transfer system via coupled magnetic resonances and a practical design method is also provided. Node equations for the resonance system are built with the method, expanding on the equations for a transformer, and the optimum distances of coils in the system are derived analytically for optimum coupling coefficients for high transfer efficiency. In order to calculate the frequency characteristics for a lossy system, the equivalent model is established at an electric design automation tool. The model parameters of the actual system are extracted and the modeling results are compared with measurements. Through the developed model, it is seen that the system can transfer power over a mid-range of a few meters and impedance matching is important to achieve high efficiency. This developed model can be used for a design and prediction on the similar systems such as increasing the number of receiving coils and receiving modules, etc.

• Korean Journal of Food Science and Technology
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• v.46 no.1
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• pp.1-6
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• 2014

An 'electronic nose' based on mass spectrometer and discriminant function analysis (DFA) was used to evaluate the grade of coffee beans. The data obtained from the electronic nose was analyzed by DFA. The discriminant function first score (DF1) of natural coffee beans showed a greater decrease than the different processing methods. Defective coffee beans were separated well from non-defective coffee beans by DF1, which correlated with a weaker flavor than that of the others. Flavor patterns of the defective and the non-defective coffee beans were determined as complementary information. The flavor patterns obtained in this study can explain, in a simplified way, the differences between the defective and the non-defective coffee beans.

• Journal of Biosystems Engineering
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• v.34 no.6
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• pp.462-469
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• 2009

The aim of this study was to develop a portable electronic nose system for freshness measurement of stored pork. An electronic nose system was constructed using seven different MOS sensor array. To determine the quality change of pork with storage time, the samples were divided into ten groups in terms of storage time with an increment of 2 day up to 19 storage days. GC-MS, total bacteria's count (TBC), thiobarbituric acid reactive substance (TBARS), and pH analyses as well as the analysis of the electronic nose system measurement were performed to monitor the freshness change of the samples. To investigate the performance of the electronic nose system for detecting the change of freshness of pork, the acquired signal values of the system were compared with those of GC-MS, TBC, TBARS, and pH analysis values. According to principal component analysis (PCA) and linear discriminant analysis (LDA) with the signals of the electronic nose system for the pork samples, the sample groups were clearly separated into two groups of 1-9 days and 11-19 days, and four groups of 1-3 days, 5-9 days, 11 days, and 13-19 days respectively. The results show that the electronic nose system has potential for evaluating freshness of pork.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.3
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• pp.209-214
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• 2009

This study was conducted to evaluate changes in the flavor patterns of gamma irradiated raw oyster and oyster cooking drip using an electronic nose, which consisted of a GC equipped with a surface acoustic wave sensor. The raw oyster was irradiated with 1, 2, 3, 4 and 5 kGy, while the oyster cooking drip was irradiated with 10 and 50 kGy. In the case of raw oyster, the intensities of peaks at retention times (RT) of 2.1 sand 6.8 s were increased, but the peak at a RT of 9.0 s was decreased depending on irradiation dose. In the case of oyster cooking drip, the intensities of peaks at RT 2.5 sand RT 4.1 s increased linearly, but at the peak at RT 5.1 s decreased as the irradiation dose increased. The total amount of flavor components measured in raw oyster increased, while that of oyster cooking drip decreased in response to irradiation.