Kyoung-ho Kang

Motion artifact reduction in electrocardiogram using adaptive filtering based on half cell potential monitoring

The electrocardiogram (ECG) is the main measurement parameter for effectively diagnosing chronic disease and guiding cardio-fitness therapy. ECGs contaminated by noise or artifacts disrupt the normal functioning of the automatic analysis algorithm. The objective of this study is to evaluate a method of measuring the HCP variation in motion artifacts through direct monitoring. The proposed wearable sensing device has two channels. One channel is used to measure the ECG through a differential amplifier. The other is for monitoring motion artifacts using the modified electrode and the same differential amplifier. Noise reduction was performed using adaptive filtering, based on a reference signal highly correlated with it. Direct measurement of HCP variations can eliminate the need for additional sensors.

43.1: A New 42-in. AC PDP Using MAoD II Driving Scheme

We present a new prototype 42″PDP using Samsung SDIs MAoD II driving scheme (Multiple Addressing with Overlapping Display period) suited for a high-resolution PDP. We used the commercial driver ICs to implement the entire parts of driving system and achieved the luminance of 600 cd/m2 with a single scan addressing method with the advantage of space charge priming. It also adopted 14 sub-fields in order to reduce the dynamic false contour.

Design of a pen-shaped input device using the low-cost inertial measurement units

In this paper, we present a pen-shaped input device equipped with accelerometers and gyroscopes that measure inertial movements when a user writes on 2 or 3 dimensional space with the pen. The measurements from gyroscope are integrated once to find the attitude of the system and are used to compensate gravitational effect in the accelerations. Further, the compensated accelerations are integrated twice to yield the position of the system, whose basic concept stems from the field of inertial navigation. However, the accuracy of the position measurement significantly deteriorates with time due to the integrations involved in recovering the handwriting trajectory This problem is common in the inertial navigation system and is usually solved by the periodic or aperiodic calibration of the system with external reference sources or other information in the filed of inertial navigation. In the presented paper, the calibration of the position or velocity is performed on-line and off-line. In the on-line calibration stage, the complementary filter technique is used, where a Kalman filter plays an important role. In the off-line calibration stage, the constant component of the resultant navigational error of the system is removed using the velocity information and motion detection algorithm. The effectiveness and feasibility of the presented system is shown through the experimental results.

Integral Effect Test on Operational Performance of the PAFS (Passive Auxiliary Feedwater System) for a SGTR (Steam Generator Tube Rupture) Accident

The PAFS is one of the advanced safety features adopted in the APR+ (Advanced Power Reactor Plus) which is intended to completely replace a conventional active auxiliary feedwater system. The PAFS cools down the steam generator secondary side and eventually removes the decay heat from the reactor core by adopting a natural convection mechanism; i.e., condensing steam in nearly-horizontal U-tubes submerged inside the PCCT (Passive Condensation Cooling Tank). With an aim of verifying the operational performance of the PAFS, the experimental program of an integral effect test is in progress at KAERI (Korea Atomic Energy Research Institute). The test facility, ATLAS-PAFS was constructed to experimentally investigate the thermal hydraulic behavior in the primary and secondary systems of the APR+ during a transient when the PAFS is actuated.Since the ATLAS-PAFS facility simulates a single train of the PAFS, the anticipated accident scenarios in the experiment include FLB (Feedwater Line Break), MSLB (Main Steam Line Break), and SGTR (Steam Generator Tube Rupture). Among them, SGTR was considered as one of the design basis accidents having a significant impact on safety in a viewpoint of radiological release. Therefore, the SGTR test was determined to be the integral effect test item in the frame of the ATLAS-PAFS experimental program.In this study, the PAFS-SGTR-HL-02 test was performed to simulate a double-ended rupture of a single U-tube in the hot side of the steam generator of the APR+. The three-level scaling methodology was taken into account to determine the test conditions of the steady-state and the transient. The pressures and temperatures of the system and the data related to the PAFS operation were collected with the measurement of the break flow.The initial steady-state conditions and the sequence of event of SGTR scenario for the APR+ were successfully simulated with the ATLAS-PAFS facility. And it was shown that the pressure and the temperature of the primary system were continuously decreased during the heat removal by the PAFS operation. The water pool in the PCCT was heated up to the saturation condition and the evaporation of the water made a decrease of the PCCT water level.It could be concluded from the present experimental result that the APR+ has the capability of coping with the hypothetical SGTR scenario with adopting the PAFS and the proper set-points of its operation.Copyright

Effect of pressurization methods on the accuracy of wrist blood pressure measurement

In developing a wrist blood pressure monitor of high and reliable accuracy, the effect of different pressurization methods on the accuracy of blood pressure measurement at the wrist using oscillometry is investigated in this paper. 30 volunteers are recruited and blood pressure readings are taken with three different methods of pressurizing the wrist. It was found that measurement of mean arterial pressure (MAP) is more accurate when the wrist is locally compressed directly over the radial artery (−2.6 ± 11.4 mmHg) or with a region of surrounding tissue (10.3 ± 6.0 mmHg) than when the whole wrist is compressed by a conventional, constricting cuff (−11.4 ± 16.4 mmHg). Characteristics of accuracy, however, differ between the two local pressurization methods. While a square airbag that compresses the wrist directly over the radial artery may measure the most accurate MAP on average, the range of errors among individuals is large. Contrarily, measurements taken by pressurizing a region over the radial artery with a bladder are least affected by individual variability. In order to measure blood pressure accurately at the wrist while unbiased by the population-based algorithmic compensation to ensure accuracy among different individuals, therefore, the use of local pressurization method may be the most appropriate.