• Journal of Sensor Science and Technology
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• v.21 no.4
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• pp.241-248
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• 2012

Recently healthcare industry such as pharmaceutical, medical device and healthcare service technology is growing significantly. Mobile healthcare has attracted big attention due to IT convergence technology. Paradigm of healthcare has been changed from the 1st generation(communicable disease prevention) and the 2nd generation(treatment of disease due to extended life expectancy) to the 3rd generation(extended life expectancy due to prevention and control). In our study, we suggest the 3rd generation mobile healthcare system using Bluetooth based wearable ECG monitoring system and smart phone technology. The mobile healthcare system consists of wearable shirts with Bluetooth communication module, ECG sensor, battery, and mobile phone. The ECG data is obtained by a miniaturized sensor and the data is transferred to a mobile phone using Bluetooth communication. Then, user can monitor his/her own ECG signal on an application using Android in mobile phone. The Bluetooth communication device is used due to highly reliable data transmission property and the Bluetooth chip is embedded in every mobile phone. The wearable shirts with chest belt of Bluetooth ECG module is designed with a focus on convenience in the daily life of a wearer. The ECG signal evaluation software in Android based mobile phone is developed for the health check and the ECG signal variation is tested according to the activities of the wearer such as walking, climbing stairs, stand up and sit down, and so on.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.12
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• pp.1201-1208
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• 2016

Radio Frequency Identification (RFID) technology has a significant attraction throughout various industry sites, along with the development of wireless communication technologies. The typical applications of RFID include medical, logistics, and distribution, and, specially, it is effectively applied to non-contact environments, because it employs radio waves. Although, recently, construction cases of the RFID management systems for the inventory management of the construction materials have been increased, the related researches and experiments for the reused materials are not actively performed. In this paper, we propose the RFID system with the localization function for effectively managing the reuse of the construction materials, adding to the conventional inventory management system. The proposed system consists of a RFID reader unit and a receiver unit, and the location information of the material with the attached RFID tag is obtained by estimating the position of a RFID reader. The distance value for estimating the reader position is calculated using the Received Signal Strength Indicator (RSSI) value of Zigbee, and the performance evaluation of the proposed system is performed in the indoor space of $5m{\times}5m$.

• Journal of Advanced Navigation Technology
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• v.14 no.1
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• pp.33-40
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• 2010

In this paper, the bit-error-ratio (BER) performances of Digital Radio Mondiale Plus (DRM+) system which stand for the European standard to bring analogue FM radio to digital radio in Band-II(30-170 MHz) are evaluated under multipath fading channel models used in Band-II and the adjacent channel interference (ACI) caused by FM signal. From the simulation results, the DRM+ system shows robust performances under time-varying channel environments even though the speed of a vehicle is equal to 300km/h. And it is shown that the frequency diversity, determined by delay spread of multipath fading channel, increases the coding gain of the DRM+ system with an increase of delay spread. In addition, to guarantee the BER performance of 10-4 for DRM+ system with ACI due to FM signal, the simulation results show that the desired signal-to-ACI power ratio must be more than -30 dB when the carrier frequency distance is 150 kHz.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.1
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• pp.220-226
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• 2011

Device of the ECG and pulse signal was made to measure PTT signal using non-invasive method and possible to wearable. PTT alterations were observed according to position change using implemented system.It was needed to ECG and pulse to detect the PTT, used the photoplethymorgraphy appeared to change the blood volume. And also wireless sensor node which was able to Zigbee compatibility was used to transfer the detected ECG and pulse signal to PC. Noise was removed from transit data and algorithm was applied to calculate the PTT. After the evaluation of both the conventional measuring systems and the proposed photoplethymography measuring system, a highly effective and efficient formation and distribution sequences were found within the proposed photoplethymography measuring system.

• Journal of Korean Society of Transportation
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• v.24 no.7 s.93
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• pp.7-14
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• 2006

Most researches about rumble strips have Presented only the before-and-after analysis of the accidents. So, Researchers have not dealt with the estimation of rumble strip's effectiveness on the driver's alertness. In this study. the effectiveness of the rumble strips on the driver's alertness was estimated by measuring the bio-signal transmitted from the driver. The bio-signal acquired for this experiments were theta wave in central lobe. The experimental results revealed that the theta waves as measured form the drivers's head while in the rumble strip section differed from those while in non-rumbled section; 74 percent decrease in theta wave value, respectively. This fact finding could mean that the driver's alertness increased from 74 percent while in the rumble strip section of the road. In all five trials of driving experiments on the rumble strip section, all the drivers showed the best alertness as measured by the theta waves in the first driving trial.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.2
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• pp.173-178
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• 2005

This paper focuses on the use of the virtual dialog system whose aim is to build more convenient living environments. In order to realize this, the main emphasis of the paper lies on the description of the multimedia signal processing on the basis of the technologies such as speech recognition, speech synthesis, video, or sensor signal processing. For essential modules of the dialog system, we incorporated the real-time speech recognizer based on HM-Net(Hidden Markov Network) as well as speech synthesis into the overall system. In addition, we adopted the real-time motion detector based on the changes of brightness in pixels, as well as the touch sensor that was used to start system. In experimental evaluation, the results showed that the proposed system was relatively easy to use for controlling electric appliances while sitting in a sofa, even though the performance of the system was not better than the simulation results owing to the noisy environments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.178-182
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• 2000

During the past five years, there has born tremendous interest worldwide in the possibility of exploiting chaos in wideband communication systems. Many different demodulation techniques have been proposed up to date. They can be divided into two basic categories. In the first approach, like the conventional coherent demodulation techniques, the chaotic signal has to be recovered from the received noisy signal by synchronization. However, the chaotic synchronization techniques published to data are so sensitive to the channel noise and distortion that these techniques can not be used in radio communications. In the second approach, the demodulation is carried out nonsynchronization. This paper surveys the different chaotic communication techniques that can be implemented nonsynchronization and compares the threshold and BER of the different methods. Finally, FM-DCSK is introduced the first step for apply to wideband chaos digital CDMA, where the data is not limited by the inherent nonperiodic property of the chaotic signal.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.7
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• pp.335-343
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• 2006

We have designed the system that measure one channel ECG by two electrode and extract real-time EDR with more related resipiration and comportable to subject by using conductive textile. On the assumption that relation between RL electrode and potential measurement electrode is coupled with RC connected model, we designed RL drive output to feedback two electrode for reduction of common mode signal. The conductive textile which was used for two ECG electrode was offered more comfort during night sleep in bed than any other method using attachments. In the method of single-lead EDR, R wave point or QRS interval area could be used for EDR estimation in traditional method, it is, so to speak, the amplitude modulation(AM) method for EDR. Alternatively, R-R interval could be used for frequency modulation(FM) method based on Respiratory Sinus Arrhythmia(RSA). For evaluation of performance on AM EDR and FM EDR from 14 subject, ECG lead III was measured. Each EDR was compared with both temperature around nose(direct measurement of respiration) and respiration signal from thoracic belt(indirect measurement of respiration) on mean squared error(MSE), cross correlation(Xcorr), and Coherence. The upsampling interpolation technique of multirate signal processing is applied to interpolating data instead of cubic spline interpolation. As a result, we showed the real-time EDR extraction processing to be implemented at micro-controller.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.1
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• pp.47-52
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• 2011

It is well known that stiffness of composites depends on layup sequence of CFRP(carbon fiber reinforced plastics) laminates because the layup of composite laminates influences their properties. Ultrasonic NDE of composite laminates is often based on the backwall echoes of the sample. A pair of such transducers was mounted in a holder in a nose-to-nose fashion to be used as a scanning probe on composites. Miniature potted angle beam transducers were used (Rayleigh waves in steel) on solid laminates of composites. Experiments were performed to understand the behavior of the transducers and the nature of the waves generated in the composite (mode, wave speed, angle of refraction). C-scan images of flaws and impact damage were then produced by combining the pitch-catch probe with a portable manual scanner known as the Generic Scanner ("GenScan"). The pitch-catch signal was found to be more sensitive than normal incidence backwall echo of longitudinal wave to fiber orientation of the CFRP composites, including low level porosity, ply waviness, and cracks. Therefore, it is found that the experimentally Rayleigh wave variation of pitch-catch ultrasonic signal was consistent with numerical results and one-side ultrasonic measurement might be very useful to detect the defects.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.5
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• pp.409-414
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• 2013

In this work, corrosion of 304 stainless steel was evaluated by using acoustic emission(AE) technique. AE measurement system was set for detecting acoustic signal during accelerated corrosion test of the specimen. AE signal started to be detected after the time of pitting corrosion initiation was evaluated by anodic polarization curve. Pitting corrosion damage was confirmed by optical microscopic observation of the surface morphology. AE cumulative counts and amplitude according to corrosion time could be divided into three stages. These trends were discussed in relation with changing pitting corrosion mechanism. Feasibilities of AE technique for evaluation of corrosion damage and mechanism were suggested.