• Journal of Electrical Engineering and Technology
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• v.7 no.1
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• pp.75-80
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• 2012

In this paper, a new energy harvesting technology using stray electric field of an electric power line is presented. It is found that energy can be harvested and stored in the storage capacitor that is connected to a cylindrical aluminum foil wrapped around a commercial insulated 220 V power line. The average current flowing into 47 ${\mu}F$ storage capacitor is about 4.53 ${\mu}A$ with 60 cm long cylindrical aluminum foil, and it is possible to operate wireless sensor node to transmit RF data every 42 seconds. The harvested average power is about 47 ${\mu}W$ in this case. Since the energy can be harvested without removing insulating sheath, it is believed that the proposed harvesting technology can be applied to power the sensor nodes in wireless ubiquitous sensor network and smart grid system.

• Journal of the Semiconductor & Display Technology
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• v.16 no.3
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• pp.31-35
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• 2017

We have fabricated flexible and stretchable pressure sensors using silver nanowires (AgNWs) and analyzed their electric responses. AgNWs are spray coated directly onto uncured polydimethylsiloxane (PDMS) such that AgNWs penetrate into the uncured PDMS, enhancing the adhesion properties of AgNWs. However, the single-layered AgNW sensor exhibits unstable electric response and low pressure sensitivity. To tackle it, we have coated a conductive polymer, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) onto the AgNW layer. Such a hybrid bilayer sensor ensures a stable electric response because the over-coating layer of PEDOT:PSS effectively suppresses the protrusion of AgNWs from PDMS during release. To enhance the sensitivity further, we have also fabricated a stacked bilayer AgNW sensor. However, its electric response varies depending sensitively on the initial overlap pressure.

• Journal of Power System Engineering
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• v.15 no.2
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• pp.55-60
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• 2011

The popularity of diesel engines is derived primarily from their higher thermal efficiency resulting from higher compression ratio. NOx removal from the diesel emissions is very important to meet stringent emission regulations. NOx emission from diesel engines is removed by an urea-SCR or an LNT system. The urea-SCR system needs the urea-solution supply system with concentration and level sensor. This study was carried out to develop a sensor for the measurement of urea-solution concentration by an electric conductivity method. Considering experimental parameters were the material of electrode, two kinds of electric power(AC or DC), the distance between two electrodes, and the length of electrode. It was found that the AC electric power was more useful to measure the urea-solution concentration compared to DC, because it prevented an ionization of the urea-solution. The silver rod coated with Pt is the most useful electrode, tendency of which is similar to Pt rod, and the cost is more economic. We could also find out the optimum distance between two electrodes and the length of electrode was 10mm and 3mm, respectively.

• Journal of Sensor Science and Technology
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• v.31 no.2
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• pp.120-124
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• 2022

With advancements in underwater stealth technology for naval vessels, new sensor configurations for detecting targets have been attracting increased attention. Latest underwater mines adopt multiple sensor configurations that include electric field sensors to detect targets and to help acquire accurate ignition time. An underwater electric field sensor consists of a pair of electrodes, signal processing unit, and preamplifier. For detecting underwater electric fields, the preamplifier requires low-noise amplification at ultra-low frequency bands. In this paper, the specific requirements for low-noise preamplifiers are discussed along with the experimental results of various setups of matched transistors and chopper stabilized operational amplifiers. The results showed that noise characteristics at ultra-low frequency bands were affected significantly by the voltage noise density of the chopper amplifier and the number of matched transistors used for differential amplification. The fabricated preamplifier was operated within normal design parameters, which was verified by testing its gain, phase, and linearity.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.21-24
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• 2005

Three dimensional circular braided Glass/Aramid hybrid fabric/epoxy resin composite was fabricated. FBG sensor was embedded along the braid yam in order to monitor the internal dimensional changes of the 3-D braid composite. The amount of cure and thermal shrinkage of epoxy resin was also determined using FBG sensor system. FBG sensors with different grating length were embedded and their response were compared. The thermo-optic coefficient of FBG sensor was measured by several preliminary experiments. The internal strain that measured by FBG sensor and electric strain gauge was compared during compressive test. The released residual strain of the fabricated tubular composite was estimated using cutting method. The internal strain of the composite was estimated using FBG sensor system, and the result was compared with the value from electric strain gauge. It was found that FBG sensor system is a very useful technique to investigate inside region of complicated structure.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.5
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• pp.121-126
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• 2005

This paper describes the attributes, performance and development status of a high performance capacitive torque sensor intended for use in a electric power steering (EPS) system. The EPS system is composed of torque sensor, ECU, motor, gears and etc. Among the elements, torque sensor in the steering column is one of the core technologies. The new capacitive torque sensor in this paper is developed differently from working principle and mechanical structure compare to extant torque sensors in market and patent. Based on the result of numerical analysis, a experimental equipment is made which is composed of a test jig and a capacitive sensor and validity of numerical analysis and feasibility of the torque sensor are verified.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.215-220
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• 2005

In order to apply to land mine detection effectively, GPR using an optical electric field sensor as a receiver has been developed. The optical electric field sensor is very small and uses optical fiber instead of metallic coaxial cable. With the combination of these advantages and the bistatic radar system, it can be possible for an operator to measure quite flexible and safely. The sensor has been tested in stepped frequency radar system with frequency which consists of a vector network analyzer, a fixed double ridged horn antenna as transmitter. For considering effectiveness in real field, we applied impulse radar system, which consist of a digital oscilloscope and a impulse generator to produce the impulse. Detection of a PMN2 mine model was carried out by the impulse radar system at a sand pit. The PMN2 were detected clearly with sufficiently high resolution, the target contrast was almost the same while the scanning time decreased down to 1/100.

• Journal of the Korean Society of Systems Engineering
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• v.20 no.spc1
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• pp.108-118
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• 2024

As shared electric kick scooters spread to cities worldwide as a result of the proliferation of personal mobility, they have emerged as a significant social issue, impacting pedestrian and user safety, as well as urban aesthetics. In this study, we propose solutions to the unique problems associated with shared electric kick scooters, such as illegal parking, charging, and redistribution. Furthermore, we present research on supplementary services utilizing electric kick scooters in urban areas to enhance citizen safety and user satisfaction through the development of an autonomous electric kick scooter system structure and operational strategies. We suggest a low-cost autonomous electric kick scooter structure and propose AI processing, sensor fusion, and system operation methods to add autonomous capabilities to affordable electric kick scooters. Additionally, we propose operational systems and related technologies for offering various supplementary services.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.335-338
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• 2005

Starting with the development of environmentally friendly electric controlled engine, sensors have played an increasing role in automotive technology. Electric power steering (EPS) systems are more and more replacing hydraulic systems. To improve fuel economy, the power assistance is provided by an electric drive. In this paper, development of a unique torque sensor for EPS is introduced. A capacitive type torque sensor is concluded to be suitable for EPS because its output is accurate, linear and robust against the variance of temperature, and patents have not applied so much.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1871-1873
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• 1997

The conventional current transformers are often take faults and out of order that for detect to over current of electric power lines because electromagnetic interference. But, it is possible to implement protection relay of high reliability using optical magnetic field sensor which are immunity and small size. The optical magnetic field sensor is possible to rapidly detect to over current and recover when electric power line have fault. And it is not necessary to make with capacitance of electric power lines as optical magnetic field sensor is have linearity from 0 to about 20kA. In this study, we designed and constructed compensative feedback circuit in order to minimize of optical power intensity variation with environ- mental variations(temperature, drive current) of light source. And this system have highest optical advantages and reliability.