• Journal of Sensor Science and Technology
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• v.26 no.2
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• pp.141-147
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• 2017

A pressure sensor in pulse measurement system is a core component for precisely measuring the pulse waveform of radial artery. A pulse sensor signal that measures the pulse wave in contact with the skin is affected by the temperature difference between the ambient temperature and skin surface. In this study, we found experimentally that the signal changes of the pressure sensors and a temperature sensor were caused by the temperature of the wrist surface while the pressure sensor was contacted on the skin surface for measuring pulse wave. To observe the signal change of the pulse sensor caused by temperature increase on sensor surface, Peltier device that can be kept at a set temperature was used. As the temperature of Peltier device was kept at $35^{\circ}C$ (the maximum wrist temperature), the device was put on the pulse sensor surface. The temperature and pressure signals were obtained simultaneously from a temperature sensor and six pressure sensors embedded in the pulse sensor. As a result of signal analysis, the sensor pressure was decreased during temperature increase of pulse sensor surface. In addition, the signal difference ratio of pressure and temperature sensors with respect to thickness of cover layer in pulse sensor was increased exponentially. Therefore, the signal of pressure sensor was modified by the compensation equation derived by the temperature sensor signal. We suggested that the thickness of cover layer in pulse sensor should be designed considering the skin surface temperature.

• Journal of Sensor Science and Technology
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• v.25 no.1
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• pp.35-40
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• 2016

Pulse diagnosis is one of the representative diagnostic methods in Oriental medicine. In this study, a pulse pressure sensor array coated with silicone, which includes 6 piezo-resistive sensors and 1 thermistor, is fabricated for pulse measurement. It is necessary to coat the pulse sensor array with silicone to avoid the fracture or damage of pressure sensors when the sensor is in contact with the skin and a constant pressure is applied. However, the silicone coating on the pulse sensor array can cause signal interference among the sensors in the pulse sensor array. The interference number (IN), a calculation for expressing the degree of interference among channels, is changed according to the silicone thickness on the pulse sensor array. The IN is increased by a thick silicone coating, but the fabrication error, an important index for the mass production of the sensor array, is reduced by the thickness of the silicone coating. We propose that the thickness of the silicone on the pulse sensor array is an important consideration for the performance of the fabricated sensor and manufacturing repeatability.

• Journal of Sensor Science and Technology
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• v.22 no.6
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• pp.439-443
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• 2013

A wireless optical fiber interferometer arterial pulse wave sensor system is developed for remote sensing. The wireless optical fiber sensor system consists of Zigbee communication modules and an optical fiber interferometer arterial pulse wave sensor. The optical fiber arterial pulse wave sensor is an in-line Michelson interferometer enclosed with steel reinforcement in a heat-shrinkable tube. The Zigbee communication modules are composed of an ATmega128L microprocessor and a CC2420 Zigbee chip. The arterial pulse waves detected by the optical fiber sensor were transmitted and received via the Zigbee communication modules. The experimental results show that the wireless optical fiber sensor system can be used for monitoring the arterial pulse waves remotely.

• Journal of the Semiconductor & Display Technology
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• v.6 no.4
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• pp.43-47
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• 2007

In this paper, we propose a novel sensor system for measuring the arterial pulse in an oral cavity. In order to measure pulse wave in oral cavity, the proposed system is designed with reflection type arterial wave sensor, not by using transmission type arterial pulse wave sensor. Driving circuit through pulse current is designed for solving self-heating problem of LED. The effectiveness of the proposed sensor system is compared with pulse wave between pulse wave of oral cavity and other body parts as well as with characteristic measurements. The experiment shows that the proposed sensor system is adaptive to capturing consecutive and meaningful biometric signals through the variation of pulse wave changes in oral cavity when exercising. The study result expects to design and develop mobile sensors which could be adapted to healthcare devices.

• Journal of Sensor Science and Technology
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• v.26 no.2
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• pp.135-140
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• 2017

In this paper, a novel measurement method of radial artery pulse waveform using robotic applanation tonometry (RAT) was present to reduce the errors by the pressing direction of the vessel. The RAT consisted of an array of pressure sensors and 2-axis tilt sensor, which was attached to the universal joint with a linear spring and five-DOF robotic manipulator with a one-axis force sensor. Using the RAT mechanism, the pulse sensor could be manipulated to perpendicularly pressurize the radial artery. A pilot experimental result showed that the proposed mechanism could find the optimal pressurization angles of the pulse sensor within ${\pm}3^{\circ}$standard deviations. Coefficient values of variation of maximum pulse peaks extracted from the pulse waveforms were 4.692, 6.994, and 11.039 % for three channels with the highest magnitudes. It is expected that the proposed method can be helpful to develop more precise tonometry system measuring the pulse waveform on the radial artery.

• Journal of Sensor Science and Technology
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• v.25 no.2
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• pp.138-142
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• 2016

A pulse measurement by tonometry provides useful information for diagnosis, including not only blood pressure and heart rate but also parameters for estimating a condition of the cardiovascular system. Currently, various pulse measurement devices based on the tonometry have been developed. A reliability of these devices is determined by a positioning technic between the sensor and the blood vessel and a controlling technique of the pressurization level. An angle of the sensor for the pulse measurement seems to be highly related with a measured signal, however, the objective studies for this issue have been not published. In this paper, the variation of the pulse signals by tonometry direction was experimentally assessed according to the angle of the sensor. In order for guaranteeing the repeatability of the experiment, we used a pulse generator device, which can generate human pulse signal by using silicon tube and fluid pump, and developed a structure for precise adjustment of the angle and the pressurization level of the sensor. The angle of the sensor was acquired by an inclinometer, which was attached at the opposite side of the sensor. As results, a coefficient of variation (CV) of a maximum amplitude (MA) of the pulse wave was largely increased over the angle range of $-9{\sim}9^{\circ}$. Furthermore, the changes of the pulse shape showed different aspects according to the sign of the angle tilted along the blood vessel. It is expected that the results of this study can be helpful for developing more precise pulse measurement devices based on the tonometry and applying in clinic.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.387-393
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• 2014

In this research, we aimed to investigate the most optimum pulse wave sensor to ear label of live stocks among pulse wave piezo film sensor, conductive textile sensor, photo sensor. As a result of this research with application to 10 cattle, 10 pigs objects with pulse wave piezo film sensor, conductive textile sensor, photo sensor, photo sensor shows less standard deviation to average value than piezo film sensor or conductive textile sensor which means it is the most stable for the cattle. With pigs, piezo film sensor, conductive textile sensor and photo sensor all show stable pulse rate. Thus, to take pulse rate of livestock with curved body and long and dense coat such as cow, photo sensor will be considered as the most efficient mean.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2B
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• pp.151-161
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• 2009

The PULSE protocol can greatly reduce power consumption using a node's sleep state. But this protocol does not consider movement of a sink node in a sensor network. In the mobile sensor network a routing protocol must recover path error by movement of a sink node as quickly as possible. Therefore we have to achieve fast path recovery and power saving to support movement of a sink node in a sensor network. This paper proposes the Mobile PULSE protocol which is a improved routing protocol for a mobile sink node. And we evaluate Mobile PULSE and show that the Mobile PULSE reduces the recovery time about 40% compared with original PULSE protocol. Mobile PULSE increases energy consumption than PULSE as a maximum of 0.8%, which means Mobile PULSE is similar to PULSE in energy consumption. This paper shows mobile PULSE's capability in the mobile sensor network through evaluation of path recovery time and power consumption.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.3
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• pp.205-209
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• 2007

Today, there are research trends about the wearable sensor device that measures various bio-signals and provides healthcare services to user using e-Health technology. This study describes the wearable sensor glove using pulse-wave sensor, conducting fabric and embedded system. This wearable sensor glove is based on the pulse-wave measurement system which is able to measure the pulse wave signal in much use of oriental medicine on the basis of a research trend of e-Health system.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.772-775
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• 2004

Generally, arterial pulse waves are measured at the radial arterial of wrist or carotid arterial of neck using a sensor such as pressure sensor, piezoelectric sensor or optic sensor. But in this paper, arterial pulse wave is measured at the temple using PZT piezo sensor which is attached on the temple in form of a hair-band. Arterial Pulse waves are generally measured when a reagent is in a static state. But in this paper, we implemented the arterial pulse wave measurement system, as a previous stage of the arterial pulse wave measurement system for running at outdoors or on a running machine, that measures arterial pulse waves at the temple, which is the least moving part when running. Thorough the continuous study, if the motion artifact when running is possible to be removed, the system will be able to perform monitoring of running men's states and especially emergency signals such as serious pulse waves of an/old and feeble persons and handicapped persons.