• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2004.10a
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• pp.49-63
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• 2004

• Progress in Superconductivity and Cryogenics
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• v.9 no.2
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• pp.1-6
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• 2007

As very sensitive magnetic field sensors, superconducting quantum interference devices (SQUIDs) are used to measure magnetic field signals from the human heart. By analyzing these cardiomagnetic signals, functional diagnoses of heart can be done. In order to measure weak biomagnetic signals, we need a multichannel SQUID array with sensor coverage large enough to cover the whole heart to enable the measurement in a single position setting. In this paper, we review the recent development of SQUID systems for measuring cardiomagnetic fields, with special emphasis on SQUID types.

• Korean Journal of Optics and Photonics
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• v.17 no.1
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• pp.54-59
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• 2006

Biophotonic sensors based on polymer waveguide with Bragg reflection grating are demonstrated in this work. Waveguide Bragg reflectors were designed by using the effective index method and the transmission matrix method. The grating pattern was formed by exposing the laser interference pattern on a photoresist. On top of the inverted rib waveguide, the Bragg reflection grating was inscribed by the O2 plasma etching. In order to perform the bio-molecule detection experiment, a calixarene molecule was self-assembled on top of thin Au film deposited on the waveguide Bragg reflector. To measure the response of the sensor, several PBS solutions with different concentrations of potassium ion from 1 pM to $100\;{\mu}M$ were dropped on the sensor surface. The shift of Bragg reflection wavelength was observed from the fabricated sensor device, which was proportional to the concentration of potassium ion ranging from 1 pM to 108 pM.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.7
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• pp.433-441
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• 2007

The bio-Sensors, which are sensing the vital signs of human bodies, are largely used by the medical equipment. Recently, the sensor network technology, which composes of the sensor interface for small-seize hardware, processor, the wireless communication module and battery in small sized hardware, has been extended to the area of bio-senor network systems due to the advances of the MEMS technology. In this paper we have suggested a design and implementation of a health care information system(called u-EMS) using a bio-sensor network technology that is a combination of the bio-sensor and the sensor network technology. In proposed system, we have used the following vital body sensors such as EKG sensor, the blood pressure sensor, the heart rate sensor, the pulse oximeter sensor and the glucose sensor. We have collected various vital sign data through the sensor network module and processed the data to implement a health care measurement system. Such measured data can be displayed by the wireless terminal(PDA, Cell phone) and the digital-frame display device. Finally, we have conducted a series of tests which considered both patient's vital sign and context-awared information in order to improve the effectiveness of the u-EMS.

• Transactions on Electrical and Electronic Materials
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• v.14 no.5
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• pp.273-277
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• 2013

A unified potentiostat circuit for both $O_2$- and $H_2O_2$- based electrochemical glucose sensors was proposed and its function was verified by circuit simulations and measurement results of a fabricated chip. This circuit consisted of an operational amplifier, a comparator and current mirrors. The proposed circuit was fabricated with a $0.13{\mu}m$ thick oxide CMOS process and an active area of $360{\mu}m{\times}100{\mu}m$. The measurements revealed an input operation range from 0.5 V to 1.6 V in the $H_2O_2$- based bio-sensor and from 1.7 V to 2.6 V in the $O_2$- based bio-sensor with a supply voltage of 3.3 V. The evaluation results showed that the proposed potentiostat circuit is suitable for measuring the electrochemical cell currents of both $O_2$- and $H_2O_2$- based glucose sensors.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.277.2-277.2
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• 2014

For next-generation electronic applications, human-machine interface devices have recently been demonstrated such as the wearable computer as well as the electronic skin (e-skin). For integration of those systems, it is essential to develop many kinds of components including displays, energy generators and sensors. In particular, flexible sensing devices to detect some stimuli like strain, pressure, light, temperature, gase and humidity have been investigated for last few decades. Among many condidates, a pressure sensing device based on organic field-effect transistors (OFETs) is one of interesting structure in flexible touch displays, bio-monitoring and e-skin because of their flexibility. In this study, we have investigated a flexible e-skin based on highly sensitive, pressure-responsive OFETs using microstructured ferroelectric gate dielectrics, which simulates both rapidly adapting (RA) and slowly adatping (SA) mechanoreceptors in human skin. In SA-type static pressure, furthermore, we also demonstrate that the FET array can detect thermal stimuli for thermoreception through decoupling of the input signals from simultaneously applied pressure. The microstructured highly crystalline poly(vinylidene fluoride-trifluoroethylene) possessing piezoelectric-pyroelectric properties in OFETs allowed monitoring RA- and SA-mode responses in dyanamic and static pressurizing conditions, which enables to apply the e-skin to bio-monitoring of human and robotics.

• Korean Journal of Agricultural Science
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• v.40 no.1
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• pp.53-59
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• 2013

Analysis of load data during field operations is highly important for optimum design of power drive lines for agricultural tractor. Objective of the paper was to analyze field load data using FFT to determine frequency and the energy levels of meaningful cyclic patterns. Rotary tillage, plowing, baling, and wrapping operations were selected as major field operations of agricultural tractor. An agricultural tractor with power measurement system was used. The tractor was equipped with strain-gauge sensors to measure torque of four driving axles and a PTO axle, speed sensors to measure rotational speed of the driving axles and an engine shaft, pressure sensors to measure pressure of hydraulic pumps, an I/O interface to acquire the sensor signals, and an embedded system to calculate power requirement. In rotary tillage, calculated frequency was decreased as travel speed increased. In baler operation, calculated frequency was increased as PTO speed was increased. The calculated peak frequency levels and expected levels were similar. Results of the study would provide information on power utilization patterns and on better design of power drive lines.

• Transactions on Electrical and Electronic Materials
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• v.13 no.4
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• pp.165-170
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• 2012

One-dimensional, nanomaterial field effect transistors (FET) are promising sensors for bio-molecule detection applications. In this paper, we review fabrication and characteristics of 1-D nanomaterial FET type biosensors. Materials such as single wall carbon nanotubes, Si nanowires, metal oxide nanowires and nanotubes, and conducting polymer nanowires have been widely investigated for biosensors, because of their high sensitivity to bio-substances, with some capable of detecting a single biomolecule. In particular, we focus on three important aspects of biosensors: alignment of nanomaterials for biosensors, surface modification of the nanostructures, and electrical detection mechanism of the 1-D nanomaterial sensors.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.127-129
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• 2010

We report the passivation characteristics of dodecanethiol (DDT) molecules on gold electrodes of field effect transistor bio-sensors. The leakage current between the electrolyte and the electrode can be as small as 3pA when 7 mM of DDT passivation is performed. The DDT layer is also shown to resist the attack of acid up to 120 mins.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1107-1108
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• 2008

The purpose of this study is to develope a computer mouse using the head movements and eye blink in order to help the disability persons who can't move the hands or foot because of car accident or cerebral apoplexy. The mouse is composed of two gyro-sensors and photo sensor. The gryo-sensors detect the head horizontal and vertical angular velocities, respectively. The photo sensor detect the eye blink to perform click, double click, and to reset the head position. In the results, we could control the mouse points in real time using the proposed system.