• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3D
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• pp.303-311
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• 2010

There have been various forms of systems such as a digital speedometer or a black box etc. to meet the social requirement for reducing traffic accidents and safe driving. However that systems are based on after-accident vehicle data, there is limit to prevent the accident before. So in our previous research, by storing, analyzing the Vehicle-dynamic information coming from driver's behavior, we are developing the decision-device which could provide driver with Alerting-Information in real-time to enhance the driver's safety drive. but the performance valuation is not yet executed. Finally, this study developed positional recognition system by using the DGPS for pre-developed risky driving decision device. The result of test analyzed with the same that the aggregated vehicle dynamics data in DGPS and dangerous risky driving decision device. If the performance of risky driving decision device is verified by precisely positional recognition system, the risky driving management of vehicle would be effected.

• IEMEK Journal of Embedded Systems and Applications
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• v.8 no.1
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• pp.61-67
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• 2013

Wheelchair users have a difficulty in managing their weight because there is lack of measure systems and even though the users have the system, it costs too much. Thus, purpose of this study is for developing the portable weight scale automatic device to help wheelchair users by monitoring their weight on the wheelchairs in real time. Portable weight scale automatic device composed by four strain gauges, and the device was connected with mobile phone so that wheelchair users were able to check their weight in real time. In order to evaluate the device performance, 10 normal subjects and 10 disabled subjects participated in this study. The subjects' truth weight and measured weight by the device are compared. The weigh difference within normal subjects was $0.75{\pm}0.80kg$, and the weigh difference within disabled subjects was $1.02{\pm}0.74kg$. Difference between the truth weigh and the measured weigh were not statistically different. The reason for this error occurred is inaccuracy of the loadcell installation and calibration. If this problems get solved, the measured indicator is expected to help wheelchair users to manage their weight.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.220-224
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• 2010

In this study, we designed a device for consecutively observing position, utilizing 3-axises acceleration sensor. This method offer to check his or her wrong position and developed could to help derived a position appliance. And, we developed a Cobb's angle value in three dimensional using 3-axises acceleration sensor. A proposed device with integrated accelerometers, which can detect postural changes in terms of curvature variation of the spine in the sagittal and coronal planes, has been developed with intention to facilitate posture training. The proposed device was evaluated with 3 normal subjects daily activities. We evaluated the performance of our designed device as calculating the correlation coefficients and mean errors between the angle measured by an electro-goniometer and that estimated by a gravity accelerometer and verified the accuracy and sensitivity. The results showed that the angle obtained from the proposed device revealed a linear characteristic at the range of $\pm60^{\circ}$(correlation coefficient 0.99, error range $\pm2^{\circ}$). We demonstrated that our device could detect the changes of the motion in upper trunk accurately. Also, our device showed good potential for treatment of the patients with scoliosis and prevention of the unbalance position during a daily life.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.334-337
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• 2002

The Quantum Hall Resistance(QHR) device which consists of GaAs/AlGaAs heterojunction structure is used for the realization of QHR Standard based on QHE. In order to characterize electrical contact resistances and dissipations of the device, it is slowly cooled down for eliminating thermal shock and unwanted noise. Then, the two properties are measured under 1.5 K and 5.15 T. Contact resistances are all within 1.2 Ω and longitudinal resistivities are all within 1 mΩ up to DC 90${\mu}$A. The results mean the device is operated well to realize the QHR Standard. To confirm it, the QHR Standard having the device is compared using a direct current comparator bridge with a 1 Ω resistance standard which the calibrated value is known from QHR standards maintained by other countries. The difference between them is agreed well within measurement uncertainty. It is thus considered that the properties of the device is estimated well and has good performance.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.6
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• pp.419-427
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• 2015

Recently Energy Saving Device has been developed actively due to the regulation of the EEDI. This Energy Saving Device which is newly developed is integrated duct and stator. This paper verified performance of the Energy Saving Device through CFD. The experimentation to find the best pitch angle of each blade of the stator designed has been conducted. The angle of incidence of the duct has been obtained through the measurement of the wake. The experimentation has been carried out with and without Energy Saving Device. The efficiency increase was through these two experiments.

• JSTS:Journal of Semiconductor Technology and Science
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• v.9 no.2
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• pp.91-97
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• 2009

The performance of GaInP/GaAs tandem solar cells with AlInP growth temperatures of 680$^{\circ}C$ and 700 $^{\circ}C$ on n-type GaAs (100) substrate with 2$^{\circ}$ and 6$^{\circ}$ tilt angles has been investigated. The series resistance and open circuit voltage of the fabricated tandem solar cells are affected by the substrate tilt angles and the growth temperatures of the window layer when zinc is doped in the tunnel diode. With carbon doping as a p-type doping source in the tunnel diode and the effort of current matching between top and bottom cells, GaInP/GaAs tandem solar cell has been exhibited 25.58% efficiency.

• The Journal of the Acoustical Society of Korea
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• v.20 no.5
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• pp.54-60
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• 2001

This paper investigates the equivalent circuit analysis method for the multi-functional device in mobile telephones, which works both as a buzzer and a vibrator in a single unit form. With a representative multi-functional device, we construct the corresponding equivalent circuits for the buzzer mode and the vibrator mode of the device, respectively, and analyze the performance of each of the modes. For proper construction of the circuit, we analyze the structure and operation mechanism of the device, and develop a computer simulation tool to simulate the behavior of the device. Validity of the analysis method is verified through comparison of the analysis results with experimental measurement results, which shows good agreement between the two sets of data.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.10
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• pp.469-475
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• 2003

Resistive leakage current flowing ZnO blocks increases with its ages, which is an important indicator of arrester deterioration. However, a complicated circuitry is essential to measure the resistive leakage current included in the total leakage current, and the difficult handling of the measurement makes few applications to the fields. In this paper, we propose a resistive leakage current measurement device which is composed of a current detection circuit and an analysis program operated on a microprocessor. The device samples the input leakage current waveform digitally, and discriminate the zero-cross and the peak point of the waveform to analyze the current amplitude vs. phase. The capacitive leakage current is then eliminated from the total leakage current by using an algorithm to extract the resistive leakage current only. Also, the device can be operated automatically and manually to analyze the resistive leakage current even when the leakage current waveform is distorted due to various types of arrester deterioration. To estimate the performance of the device, we carried out a test on ZnO blocks and lightning arresters. From the results, it is confirmed that the device could analyze most parameters needed for the arrester diagnostics such as total leakage current. resistive leakage current, and the $3^rd$ harmonic leakage current.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.9
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• pp.614-619
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• 2010

Recently, a problem related to the thermal management in portable electronic and telecommunication devices is becoming issued. That is due to the trend of a slimness of the devices, so it is not easy to find the optimal thermal management solution for the devices. From now on, a pressed circular type cooling device has been mainly used, however the cooling device with thin thickness is becoming needed by the inner space constraint of the applications. In the present study, the silicon flat plate type cooling device with the separated vapor and liquid flow path was designed and fabricated. The normal isothermal characteristics created by vapor-liquid phase change was confirmed through the experimental study. The cooling device with 70 mm of total length showed 6.8 W of the heat transfer rate within the range of $4{\sim}5^{\circ}C/W$ of thermal resistance. In the future, it will be possible to develop the commercialized cooling device by revising the fabrication process and enhancing the thermal performance of the silicon and glass cooling device.

• Korean Journal of Clinical Pharmacy
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• v.19 no.1
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• pp.65-68
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• 2009

Disposal infusion device is known to be useful for chemotherapy. Anti-cancer drug can be released by the force of carbon dioxide or balloon. In this study, we compared the$Anapa^{(R)}$ (LC0020) with B Company (LV2 ml) in terms of infusion rate and stability. Infusion rate was determined every six minute using software, MSI08IH. Stability of 5-fluorouracil was examined periodically using a High Performance Liquid Chromatography. Infusion rates of gas-derived $Anapa^{(R)}$ device were 2.29, 1.86, 1.98 ml/hr and those of balloon-derived B Company device were 1.71, 1.58, 1.37 ml/min. There were no significant differences in stability of 5-fluorouracil between $Anapa^{(R)}$ and B Company devices. In summary, gas-derived $Anapa^{(R)}$ device is thought to be comparable or superior to balloon-derived B Company device as far as infusion rate and stability are concerned. We expect that $Anapa^{(R)}$ as a home infusion device can be employed to improve a quality of life and compliance of cancer patients.