• Journal of Sensor Science and Technology
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• v.32 no.4
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• pp.246-251
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• 2023

Internet of Things (IoT) systems process signals from various sensors using signal processing algorithms suitable for the signal characteristics. To analyze complex signals, these systems usually use signal processing algorithms in the frequency domain, such as fast Fourier transform (FFT), filtering, and short-time Fourier transform (STFT). In this study, we propose a multi-mode sensor signal processor (SSP) accelerator with an FFT-based hardware design. The FFT processor in the proposed SSP is designed with a radix-2 single-path delay feedback (R2SDF) pipeline architecture for high-speed operation. Moreover, based on this FFT processor, the proposed SSP can perform filtering and STFT operation. The proposed SSP is implemented on a field-programmable gate array (FPGA). By sharing the FFT processor for each algorithm, the required hardware resources are significantly reduced. The proposed SSP is implemented and verified on Xilinxh's Zynq Ultrascale+ MPSoC ZCU104 with 53,591 look-up tables (LUTs), 71,451 flip-flops (FFs), and 44 digital signal processors (DSPs). The FFT, filtering, and STFT algorithm implementations on the proposed SSP achieve 185x average acceleration.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.925-928
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• 1999

A multi-channel gas leakage monitoring system was designed and fabricated by using CPLD(complex Programmable Logic .Device) for monitoring and controlling the leakage of natural gas from supplying-pipes under the ground. Fabricated SnO$_2$thick film gas sensor elements were attached on safeguard steel plate of natural gas supplying pipes, and the local monitoring system in this study received the signal from the gas sensors. The monitoring system was implemented by using CPLD chip to reduce the development time and implement simple one chip system. The time division multi-channel system received the input signal from individual gas sensor at one of divided times by multiplexor and signal processed sequentially. The system reduced the size of peripheral circuit resulted in implementation of creditable simple system.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.244-250
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• 1997

The mean time to failure (MTTF) expressing the mean value of the system life is a measure of system effectiveness. To estimate the remaining life of component and/or system, the dynamic mean time to failure concept is suggested. It is the time-dependent Property depending on the status of components. The Kalman filter is used to estimate the reliability of components using the on-line information (directly measured sensor output or device-specific diagnostics in the intelligent sensor) in form of the numerical value (state factor). This factor considers the persistency of the fault condition and confidence level in measurement. If there is a complex system with many components, each calculated reliability's or components are combined, which results in the dynamic MTTF or system. The illustrative examples are discussed. The results show that the dynamic MTTF can well express the component and system failure behaviour whether any kinds of failure are occurred or not.

• Journal of Korea Multimedia Society
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• v.22 no.2
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• pp.281-291
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• 2019

In order to reflect complex and diverse building types, resident characteristics and disaster factors, it is necessary to introduce a flexible situation-based response system based on real-time information. Intelligent CCTV, hybrid sensor, location scanner, and customized broadcasting device were examined to introduce for the real-time response intelligent response system and its feasibility was verified through field test. In addition, based on the real-time information, the evacuation simulation was executed by assuming the dormitory building and the resident of the school, and the safety of the evacuation and the shortening of the pinnacle time were confirmed. The feasibility of real time information based evacuation comparing with the existing evacuation system were verified in the case of evacuation.

• Journal of Sensor Science and Technology
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• v.21 no.1
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• pp.21-27
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• 2012

In this study, we designed an embedded system for automatic condensation control(ESCC) of the car. This system heats the car glasses as and when it is needed that makes driving safer and convenient. The system was built on an ATmega128L central processing unit(CPU), using high-performance electrically erasable programmable read-only memory(EEPROM) complex programmable logic device(CPLD) ATF1504AS, using which an ESCC algorithm has been proposed. The source code was written in C language. The algorithm of work was written using the dew-point table. This system not only clears the condensation on the glass but also averts condensation. The designed ESCC system begins working once the input information comes close to the dew-point table information. This device enables a wider field of view, thereby increasing safety.

• 전자공학회논문지 IE
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• v.48 no.3
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• pp.26-32
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• 2011

This paper proposed that the method be searched for optimal route of evacuation by algorithm using potential field in specific situation, fire. When robot met an obstacle to be indicated it to ignition point, the installed sensor could be detected the point in restricted area. In according as the data of a fire detection sensor and a sensor complex in a building, the information was transmitted to server which computed optimal route of evacuation by algorithm using potential field. After that, it was able to blow a siren and mark the safe-path with using wireless device such as smart-phone. It was confirmed that the proposed method in functional test, fire emergency evacuation algorithm using potential field, was advanced in circumstance of simulation.

• Journal of Sensor Science and Technology
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• v.22 no.5
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• pp.364-368
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• 2013

Vibrational energy harvester based on piezoelectricity has been expected to be the dominant energy harvesting technology due to the advantages of high conversion efficiency, light weight and small size, night operation, etc. Its commercialization is just around the corner but the integration with power management electronics should be solved in advance. In this paper, therefore, fully-integrated design environment for piezoelectric energy harvesting systems is presented to assist co-design with the power management electronics. The proposed design environment is capable of analyzing the energy harvester including the package-induced damping effects and simulating the device and its power management electronics simultaneously. When the developed design environment was applied to the fabricated device, the simulated resonant frequency matched well with the experimental result with a difference of 2.97% only. Also, the complex transient response was completed in short simulation time of 3,001 seconds including the displacement distribution over the device geometry. Furthermore, a full-bridge power management circuit was modeled and simulated with the energy harvester simultaneously. Therefore the proposed, fully-integrated design environment is accurate and fast enough for the contribution on successful commercialization of piezoelectric energy harvester.

• Journal of Sensor Science and Technology
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• v.28 no.4
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• pp.236-239
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• 2019

In this work, we performed an optical simulation study on the performance of a PMDPP3T:PCBM based on an organic photovoltaic (PV) device. The virtual PV device was developed in Lumerical, finite-difference time-domain (FDTD) solutions. Different layers of the PV cell have been defined through the incorporation of complex refractive index value of those layers' constituent materials. During the simulation study, the effect of the variation active layer thickness on an ideal short circuit current density ($J_{sc,ideal}$) of the PV cell has been, first, observed. Thereafter, we have investigated the impact of surface roughness of a transparent conducting oxide (TCO) electrode on $J_{sc,ideal}$ of the PV cells. From this simulation, it has been observed that the $J_{sc,ideal}$ value of the PV cell is strongly dependent on the thickness of its active layer and the photon absorption of the PV cell has gradually decreased with the increment of the TCO's surface roughness. As a result, the capability of the PV device has been reduced with the increment of the surface roughness of the TCO.

• Journal of Korea Artificial Intelligence Association
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• v.2 no.1
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• pp.25-30
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• 2024

Kodály hand signs are symbols that intuitively represent pitch and note names based on the shape and height of the hand. They are an excellent tool that can be easily expressed using the human body, making them highly engaging for children who are new to music. Traditional hand signs help beginners easily understand pitch and significantly aid in music learning and performance. However, Kodály hand signs have distinctive features, such as the ability to indicate key changes or chords using both hands and to clearly represent accidentals. These features enable the effective use of Kodály hand signs. In this paper, we aim to investigate the changes in recognition rates according to the complexity of scales by creating a device for learning Kodály hand signs, teaching simple Do-Re-Mi scales, and then gradually increasing the complexity of the scales and teaching complex scales and children's songs (such as "May Had A Little Lamb"). The learning device utilizes accelerometer and bending sensors. The accelerometer detects the tilt of the hand, while the bending sensor detects the degree of bending in the fingers. The utilized accelerometer is a 6-axis accelerometer that can also measure angular velocity, ensuring accurate data collection. The learning and performance evaluation of the Kodály learning device were conducted using Python.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.3
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• pp.347-358
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• 2016

The paper presents a software architecture for a wearable device to measure vital signs with the real-time user's behavior recognition. Taking vital signs with a wearable device help user measuring health state related to their behavior because a wearable device is worn in daily life. Especially, when the user is running or sleeping, oxygen saturation and heart rate are used to diagnose a respiratory problems. However, in measuring vital signs, continuosly measuring like the conventional method is not reasonable because motion artifact could decrease the accuracy of vital signs. And in order to fix the distortion, a complex algorithm is not appropriate because of the limited resources of the wearable device. In this paper, we proposed the software architecture for wearable device using a simple filter and the acceleration sensor to recognize the user's behavior and measure accurate vital signs with the behavior state.