• Journal of rehabilitation welfare engineering & assistive technology
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• v.9 no.2
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• pp.137-144
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• 2015

In this paper, we present an inertial sensor-based gait analysis system to measure and analyze lower-limb movements. We developed an integral AHRS(Attitude Heading Reference System) using a combination of rate gyroscope, accelerometer and magnetometer sensor signals. Several AHRS modules mounted on segments of the patient's body provide the quaternions representing the patient segments's orientation in space. And a method is also proposed for calculating three-dimensional inter-segment joint angle which is an important bio-mechanical measure for a variety of applications related to rehabilitation. To evaluate the performance of our AHRS module, the Vicon motion capture system, which offers millimeter resolution of 3D spatial displacements and orientations, is used as a reference. The evaluation resulted in a RMSE(Root Mean Square Error) of 1.08 and 1.72 degree in yaw and pitch angle. In order to evaluate the performance of our the gait analysis system, we compared the joint angle for the hip, knee and ankle with those provided by Vicon system. The result shows that our system will provide an in-depth insight into the effectiveness, appropriate level of care, and feedback of the rehabilitation process by performing real-time limb or gait analysis during the post-stroke recovery.

• KSBB Journal
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• v.22 no.6
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• pp.378-386
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• 2007

Bio-sensing devices, which are basically integrated and miniaturized assay systems consisted of bioreceptor and signal transducer, are advantageous in several ways. In addition to their high sensitivity, selectivity, simplicity, multi-detection capability, and real time detection abilities, they are both very small and require relatively inexpensive equipments. Two core technologies are required to develop bio-sensing devices; the fabrication of biological receptor module (both of receptor development and immobilisation of them) and the development of signal transducing instruments containing signal generation technique. Various biological receptors, such as enzymes, DNA/RNA, protein, and cell were tried to develop bio-sensing devices. And, the signal transducing instruments have also been extensively studied, especially with regard to electrochemical, optical, and mass sensitive transducers. This article addresses bio-sensing devices that have been developed in the past few years, and also discusses possible future major trends in these devices.

• Journal of Biomedical Engineering Research
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• v.25 no.1
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• pp.21-26
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• 2004

Recently, many people want to know their state of health, such as a body fat rate, anywhere and anytime. The Personal Digital Assistance(PDA) is the portable wireless apparatus that has become widely popular. There are many application areas of the IDA to be in mobile care devices. In this study, we developed the PDA based body fat measurement system, composed of a cradle type measurement module and a WindowCE operated software module, a regression equation for predicting lean body mass (LBM). Sixty-three weight-stable subjects (53 men, 10 women) aged 20∼32yr participated in this study. A regression model, LBM ＝ (0.0005＊Height2 - 0.0160＊Impedance ＋ 0.3920＊Weight - 0.0684＊Age - 5.8141＊Sex ＋ 25.984, was found. The correlation coefficient( r) of body fat rate between developed system and HTM1000plus(BionetTM) was 0.928. HTM1000plus is a commercially available and approved by KFDA. These results indicated that developed system is reliable for estimation of body fat rate. Although developed system is the PDA based miniaturized, it shows good performance comparing with other commercial product.

• The KIPS Transactions:PartB
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• v.11B no.7 s.96
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• pp.759-768
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• 2004

Recently the biometric recognition technology is intensively studied and the standardization of the technology has been highly demanded for its commercialization. Currently many blometric recognition products are being developed based on the BioAPl(Biometric Application Program-ming Interface) specification. However, the reliable testing tools (or scenarios) to evaluate performance and conformance of the products are not shown yet. In this paper, a conformance testing method is presented, which verifies a biometric recognition system to meet the requirements of the BioAPl standard. Two different testing procedures are used in the proposed method. The first procedure evaluates that each functions offered in the BioAPl specification are correctly implemented and that the functions are actually used in the system. Through the Procedure, a BSP(Biometric Service Provider) system is executed on the framework of the BioAPl functions. It requires selection of parameters and prece-dent functions that should be executed first. The second procedure evaluates the abilities of module management, handling operations and ver-ification process by the analysis of the test cases. It tests the correctness of the system operation when a testing scenario is given. The proposed testing method is applied on a fingerprint verification BSP using the sample BSP provided by the BioAPl consortium. The experimental results shows the benefits of the proposed testing method.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.2
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• pp.221-231
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• 2013

Exchanging personal health information(PHI) is an essential process of healthcare services using information and communication technology. But the process have the inherent risk of information disclosure, so the PHI should be protected to ensure the reliability of healthcare services. In this paper, we designed encryption module for wearable personal health devices(PHD). A main goal is to guarantee that the real-time encoded and transmitted PHI cannot be allowed to be read, revised and utilized without user's permission. To achieve this, encryption algorithms as DES and 3DES were implemented in modules operating in Telos Rev B(16bit RISC, 8Mhz). And the experiments were performed in order to evaluate the performance of encryption and decryption using vital-sign measured by PHD. As experimental results, an block encryption was measured the followings: DES required 1.802 ms and 3DES required 6.683 ms. Also, we verified the interoperability among heterogeneous devices by testing that the encrypted data in Telos could be decoded in other machines without errors. In conclusion, the encryption module is the method that a PHD user is given the powerful right to decide for authority of accessing his PHI, so it is expected to contribute the trusted healthcare service distribution.

• Proceedings of the KAIS Fall Conference
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• 2006.05a
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• pp.252-257
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• 2006

감성은 인간의 생활에서 논리적 사고와 의사결정, 감정의 발생, 행동 등 모든 부분에 깊숙이 영향을 미치고 있어, 최근 감성의 개념을 도입한 공학적 제품의 도입이 활성화되어 여러 분야에 다양하게 사용 되어지고 있다. 그러나 감성을 평가함에 있어서는 단순한 해석의 의미 수준을 벗어 인간의 삶을 향상시키기 위한 제품이나 환경의 개발을 위해서는 인간의 감성을 정확하게 이해한다는 것은 체계적인 연구와 활용을 위한 선행 조건이라 할 수 있어, 생리신호등을 이용한 정량화된 감성평가 알고리즘의 개발 필요성이 있다. 특히, 최근 여러 IT기기들이 주변의 다양한 기술을 융합하여 다기능의 기기로 변모를 하고 있으며, 이러한 IT기기들에 인간의 감성을 평가할 수 있는 모듈을 부가하여 인간친화적인 기기로의 변모를 도모하고 있는 실정이다. 따라서, 본 연구에서는 측정이 용이한 소수의 생리신호만으로 간단하게 인간감성을 정량적으로 평가가 가능하며, SoC등에 간단하게 탑재할 수 있도록 시스템의 리소스를 적게 소비하는 소형 경량의 감성평가알고리즘을 개발하였다.

• Journal of Biomedical Engineering Research
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• v.21 no.3 s.61
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• pp.311-320
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• 2000

In this paper a newly designed oxygenator module was used to perform the experiments for pressure drop and oxygen transport in order to evaluate the efficiency of the artificial lung. Also, distilled water. sodium sulfite solutions used in this experiment were evaluated for the performance of other artificial lungs. Substituted bloods have many advantages over whole blood in studying pressure drop and oxygen uptake. They are relatively inexpensive, and require fewer variables to be controlled. Furthermore, deoxygenation is not necessary when those solutions are used. In addition to these advantages. assays and interpretation of the experimental results are relatively easy. In the case of using the sodium sulfite solution having the same oxygen partial pressure as whole blood. the oxygen transfer rate of the sodium sulfite solution was basically same as that of whole blood. It was concluded in evaluating the function of artificial lungs that the sodium sulfite solution was suited for measuring oxygen transfer rate. In our module, artificial blood was flowed into the outside of hollow fiber membrane. The artificial lung created in this experiment showed that pressure drop was reduced to $1/3\~1/6$ of that compared to the inside-flow case.

• Journal of Biomedical Engineering Research
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• v.20 no.4
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• pp.461-469
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• 1999

In this paper, an ECG-NIBP patient monitor is designed. This is an essential equipment to measure and monitor patient's physical condition - electrocardiogram(ECG) wave, heart rate(HR), and noninvasive blood pressure(NIBP) - in ICU, CCU, and operating room. The ECG is an electrical waveform produced by relaxation and contraction of the cardiac muscle. Most physicians diagnose patient's cardiac states from ECG pattern. A blood pressure is one of the clinical indexes measured in a emergency room or operating room. In this paper, the blood pressure is measured in artery by using the nonivasive oscillometric method. The developed patient monitor was inspected and compared with other instruments in operating rooms. The results were 1bpm of maximum difference in the heart rate, 15mmHg in the systolic pressure, 16mmHg in the diastolic pressure, and 25mmHg in the mean blood pressure. But the total results were 0.15bpm of the mean difference in the heart rate, 5mmHg in the systolic pressure, 10mmHg in the diastolic pressure, and 9mmHg in the mean blood pressure. The designed ECG-NIBP patient monitor can measure the ECG wave, HR, and BP. And the multi-tasking module of pulse oximetry . respiration . temperature monitor will be added in the near future.

• Journal of Biomedical Engineering Research
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• v.25 no.4
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• pp.269-275
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• 2004

Different biological tissues have different values of electrical resistivity. In EIT (electrical impedance tomography), we try to provide cross-sectional images of a resistivity distribution inside an electrically conducting subject such as the human body mainly for functional imaging. However, it is well known that the image reconstruction problem in EIT is ill-posed and the quality of a reconstructed image highly depends on the measurement error. This requires us to develop a high-performance EIT system. In this paper, we describe the development of a 16-channel digital EIT system including a single constant current source, 16 voltmeters, main controller, and PC. The system was designed and implemented using the FPGA-based digital technology. The current source injects 50KHz sinusoidal current with the THD (total harmonic distortion) of 0.0029% and amplitude stability of 0.022%. The single current source and switching circuit reduce the measurement error associated with imperfect matching of multiple current sources at the expense of a reduced data acquisition time. The digital voltmeter measuring the induced boundary voltage consists of a differential amplifier, ADC, and FPGA (field programmable gate array). The digital phase-sensitive demodulation technique was implemented in the voltmeter to maximize the SNR (signal-to-noise ratio). Experimental results of 16-channel digital voltmeters showed the SNR of 90dB. We used the developed EIT system to reconstruct resistivity images of a saline phantom containing banana objects. Based on the results, we suggest future improvements for a 64-channel muff-frequency EIT system for three-dimensional dynamic imaging of bio-impedance distributions inside the human body.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.10
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• pp.1485-1490
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• 2013

The demonstration project of the electrical grid for Smart grid is progressed, the smart digital appliances AV technology, Smart home energy management technology charging the management function of complex energy for the automation management of air conditioning and heating, humidity and air, the health care technology charging the design of housing for the elderly and disabled and the measurement of individual bio information, and the Smart home security technology dealing with the biometric security and motion sensors, etc. have been studied. The power monitoring terminal which uses a variety of wired and wireless networks and protocol is the target additionally to be considered in addition to the security vulnerabilities that was occurred in the existing terminal. In this research paper, the author analyzes the cryptographic techniques corresponding to the smart meter occurred by the problems that are exposed on the outside which are vulnerable to physical attacks, and intends to propose the design of the security systems for the Smart meter terminal being able to maximize the efficiency of the terminal.