• Journal of the Institute of Electronics Engineers of Korea SC
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• 제46권6호
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• pp.44-49
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• 2009

EAS (electronic article surveillance) systems have increased rapidly for article surveillance. In this paper, the strength of the EMF (electromagnetic fields) of EAS systems were measured. Pacemaker and ICD were investigated for inappropriate response resulting from EM (electromagnetic) EAS systems. The strength of EMF and the response of pacemaker and ICD were measured in the inner left side, outer right sides and the center of gates of the 6.3 kHz and 14.25 kHz EAS systems at a height of 130cm. As the result, EMF of the EAS system using 14.25 kHz was stronger than that of 6.3 kHz. AU interferences were observed only for 14.25 kHz, and the noisy ECG was found in three static positions on the pacemaker. The ICD resulted in noise reversion and VF (ventricular fibrillation) both static and moving positions by the EMP of 14.25 kHz EAS system. Therefore, it is necessary to post a message warning radiation of EMF from every EAS systems and possible risk of pacemakers and ICDs.

• The Journal of the Acoustical Society of Korea
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• 제15권4호
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• pp.24-31
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• 1996

In this paper, we present a speech translation system for hotel reservation, KT_STS(Korea Telecom Speech Translation System). KT-STS is a speech-to-speech translation system which translates a spoken utterance in Korean into one in Japanese. The system has been designed around the task of hotel reservation(dialogues between a Korean customer and a hotel reservation de나 in Japan). It consists of a Korean speech recognition system, a Korean-to-Japanese machine translation system and a korean speech synthesis system. The Korean speech recognition system is an HMM(Hidden Markov model)-based speaker-independent, continuous speech recognizer which can recognize about 300 word vocabularies. Bigram language model is used as a forward language model and dependency grammar is used for a backward language model. For machine translation, we use dependency grammar and direct transfer method. And Korean speech synthesizer uses the demiphones as a synthesis unit and the method of periodic waveform analysis and reallocation. KT-STS runs in nearly real time on the SPARC20 workstation with one TMS320C30 DSP board. We have achieved the word recognition rate of 94. 68% and the sentence recognition rate of 82.42% after the speech recognition tests. On Korean-to-Japanese translation tests, we achieved translation success rate of 100%. We had an international joint experiment in which our system was connected with another system developed by KDD in Japan using the leased line.

• Journal of Life Science
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• 제22권9호
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• pp.1214-1223
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• 2012

This study analyzed the in vitro physiological activity of Aconitum pseudolaeve var erectum Nakai (AP) and its effect on perfume on an electroencephalogram (EEG). The results indicated that the absolute alpha power spectrum (AA) and the absolute theta power spectrum (AT) decreased significantly during more than before the inhalation of the AP perfume and its reconstruction perfume. Although there were a little different pattern in the induced part of the wave generated by the inhalation of the AP perfume and its reconstruction perfume, alpha- and theta- were shown equally. In addition, there was the same pattern in which the rate of increase reduced. The results suggest that the perfume of the AP and its reconstruction perfume have a stimulating effect on the brain. In terms of the physiological activity of AP, the activity of AP ethanol extract was significantly higher than that of water extract in DPPH, collagenase, and nitric oxide, except for an astringent effect. The AP ethanol extract was about 80% at 500 ppm in collagenase inhibition activity. In addition, the AP water and ethanol extracts were 50% at 100 ppm in the NO inhibition activity. Based on these results, we conclude that this natural substance could be used in cosmetics and in the development of perfumes.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제18권6호
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• pp.602-611
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• 2007

In this paper, the forward link of UHF RFID system is modeled in accordance with the EPCglobal class 1 generation 2(EPCglobal C1G2) UHF Radio-Frequency Identity protocol specification at $860{\sim}960MHz$. Based on the constructed model, characteristics on the forward link signal for the EPCglobal C1G2 RFID reader are simulated with the help of a MATLAB softwarein order to extract the design parameters of a transmit digital filter which meets the Korean RFID regulations. Herein, the forward link model is consisted of PIE source coding, transmit digital filter, modulation, local oscillator, and antenna. From the simulation results, the ranges of three design parameters(roll-off factor, cutoff frequency, the number of tabs) for transmit digital filter are obtained with different modulation techniques and the Tari(type a reference interval) values. Finally, DSB/SSB-ASK modulation technique can not satisfy the EPCglobal C1G2 specification when Tari equals to $6.25{\mu}sec$ in a multiple-reader environment. Consequently this paper can provide a guideline for design parameters of a RFID reader as well as the basic scheme of analyzing frequency interference problems in RFID environments, including multiple-reader and dense-reader environments.

• Journal of Biomedical Engineering Research
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• 제25권6호
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• pp.431-438
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• 2004

Medical ultrasonic imaging is a useful imaging facility known to be most safe and easy. It enables physicians to observe the inside structures of the bodies, blood flow, and motions of internal organs. Some physical properties of biologic tissues can also be estimated from backscattered sounds. However, the ultrasonic pulses interrogating the living organisms leave their footprints in the returning signals during imaging. Some significant details are buried in the footprints and their overlaps from adjacent particles. These distortions also decrease the quality of the images. Many research efforts have been made to enhance the image quality and to recover the acoustic information in various ways. In this study, a new interrogation method based on the wavelet and subband filter bank is proposed. It adopts the subband wavelet filters satisfying the perfect-reconstruction (PR) conditions as the interrogating pulses to restore the details useful in tissue characterization and to enhance the image quality. The proposed method was applied to two types of simulations of ultrasonic imaging. The results showed its ability to restore the detailsin the simulated interrogation of biologic tissues, and verified the improved image quality in the simulated imaging of general ultrasonic phantom compared with the conventional method.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제40권12호
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• pp.1047-1053
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• 2016

In this study, welding of pure titanium was carried out by using a continuous wave fiber laser with a maximum output of 6.3 kW. Because brittle regions form easily in titanium as a result of oxidation or nitriding, the weld must be protected from the atmosphere by using an appropriate shielding gas. Experiments were performed by changing the type and the flow rate of shielding gases to obtain the optimal shielding condition, and the weldability was then evaluated. The degree of oxidation and nitriding was distinguished by observing the color of beads, and weld microstructure was observed by using an optical microscope and a scanning electron microscope. The mechanical properties of the weld were examined by measuring hardness. When the weld was oxidized or nitrified, the bead color was gray or yellow, and the oxygen or nitrogen content in the bead surface and overall weld tended to be high, as a result of which the hardness of the weld was thrice that of the base metal. A sound silvery white bead was obtained by using Ar as the shielding gas.

• Journal of the Korean Institute of Gas
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• 제20권6호
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• pp.50-57
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• 2016

Pipeline is one of the most abundant components in petrochemical plant. It plays a critical role in transporting fluids. Some pipelines are thermally insulated by wrapping them with insulating materials to prevent the loss of energy. However, when corrosion begins under insulation, it cannot be easily seen without unwrapping the cover, and thus corrossion should be detected using a non-destructive ways such as ultrasound guided wave. In this paper, the piping where the CUI (Corrosion Under Insulation) which occurs in the insulation parts guided waves effectively the optimum condition which is theoretical for selected guided waves phase velocity dispersion curve and wave-structure. The results of this study are expected to be directly utilized for onsite inspection of pipeline's CUI in many petrochemical plants.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제13권12호
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• pp.2511-2517
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• 2009

Recently, a FMCW radar is used for the various purposes in the short range detection and tracking of targets. The main advantages of a FMCWradar are the comparative simplicity of implementation and the low peak power transmission characterizing the very low probability of signal interception. Since it uses the frequency modulated continuous wave for transmission and demodulation, the received beat frequency represents the range and Doppler information of targets. Detection and extraction of useful information from targets are performed in this beat frequency domain. Therefore, the resolution and accuracy in the estimation of a beat spectrum are very important. However, using the conventional FFT estimation method, the high resolution spectrum estimation with a low sidelobe level is not possible if the acquisition time is very short in receiving target echoes. This kind of problems deteriorates the detection performance of adjacent targets having the large magnitude differences in return echoes and also degrades the reliability of the extracted information. Therefore, in this paper, the model parameter estimation methods such as autoregressive and eigenvector spectrum estimation are applied to mitigate these problems. Also, simulation results are compared and analyzed for further improvement.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제17권8호
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• pp.1947-1954
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• 2013

Previous works for detecting arrhythmia have mostly used nonlinear method such as artificial neural network, fuzzy theory, support vector machine to increase classification accuracy. Most methods require accurate detection of P-QRS-T point, higher computational cost and larger processing time. But it is difficult to detect the P and T wave signal because of person's individual difference. Therefore it is necessary to design efficient algorithm that classifies different arrhythmia in realtime and decreases computational cost by extrating minimal feature. In this paper, we propose arrhythmia detection based on binary coding using QRS feature varibility. For this purpose, we detected R wave, RR interval, QRS width from noise-free ECG signal through the preprocessing method. Also, we classified arrhythmia in realtime by converting threshold variability of feature to binary code. PVC, PAC, Normal, BBB, Paced beat classification is evaluated by using 39 record of MIT-BIH arrhythmia database. The achieved scores indicate the average of 97.18%, 94.14%, 99.83%, 92.77%, 97.48% in PVC, PAC, Normal, BBB, Paced beat classification.

• The Transactions of the Korean Institute of Power Electronics
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• 제10권6호
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• pp.560-568
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• 2005

The proposed Multi-level PDP sustain Driver is composed of the semiconductor devices with low voltage rating compared to those used in the prior circuit proposed by L. Wether, and it has two resonant periods during the charging (rising period) and discharging (falling period) the PDP in the sustaining voltage waveforms. In accordance with the change of timing phase$(T_{r1},\;T_{i1},\;T_{r2})$, the performance characteristics of a commercial PDP module has been carried out and compared the characteristic with the 42V6, made of LG Electronics co., Experimental results show that the performance characteristics of PDP module are greatly influenced by the variation of $T_{i1}\;and\;T_{r2}$. The variation of $T_{r1}$ do not influence much on the performances of PDP. With the conditions that $T_{r1}=60ns,\;T_{i1}=120ns,\;and\;T_{r2}=350ns$, we could get the performances listed as the luminance is increased $14.6\%$, the power consumptions is decreased $5.9\%$, the panel efficiency is increased $24.2\%$, module efficiency is increased $21.2\%$, compared to those shown in the commercial PDP module (42V6). Therefore, the proposed multi-level PDP sustain driver expected to be suitable to actual PDP module application.