• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.4
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• pp.673-677
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• 2016

In this study, In order to measure foot pressure, it makes analyzing device using multi-pressure sensor. This device was limited frequency band to 5Hz by using low-pass filter and MCU was detected signal every milliseconds. After wearing the device, the result was confirmed by blue-tooth to measure wirelessly. Also, we propose an algorithm to obtain the walking pattern using a time table in each of the detected peak from the pressure sensor. Using the algorithm, right walking pattern and abnormal pattern was detected. The results can be reflected more individual walking patterns than when using a conventional methods and also, developed device was no restriction on the human activity.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.2
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• pp.53-57
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• 2017

This papers propose a Hall-effect sensors position error compensation method in a sunroof system using a BLDC motor with a low-cost MCU. If the BLDC motor is controlled with this wrong position, the torque ripple and operating current can be increased and the average torque also decreases. Generally, sunroof system has characteristics that operate at constant load for several seconds. It is possible to find the minimum operating current value while changing the position of the Hall-effect sensor during the sunroof operation by using these characteristics. Therefore, propose a method to change the Hall-effect sensor position and find the minimum current value. The validity of the proposed algorithm is verified through experiments.

• Journal of Sensor Science and Technology
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• v.29 no.5
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• pp.303-311
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• 2020

Nondispersive infrared CO₂ gas sensor was developed after the simulation of optical cavity structure and assembling the optical components: IR source, concave reflectors, Fresnel lens, a hollow disk, and IR detectors. By placing a hollow disk in front of reference IR detector, the output voltages are almost constant value, near to 70.2 mV. The absorbance of IR light, F_a, shows the second order of polynomial according to ambient temperatures at 1,500 ppm. The differential output voltages and the absorbance of IR light give a higher accuracy in estimations of CO₂ concentrations with less than ± 1.5 % errors. After implementing the parameters that are dependent upon the ambient temperatures in microcontroller unit (MCU), the measured CO₂ concentrations show high accuracies (less than ± 1.0 %) from 281 K to 308 K and the time constant of developed sensor is about 58 sec at 301 K. Even though the estimation errors are relatively high at low concentration, the developed sensor is competitive to the commercial product with a high accuracy and the stability.

• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.2134-2143
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• 2018

This work introduces a fault diagnosis method for transformer based on self-powered radio frequency identification (RFID) sensor tag and improved Hilbert-Huang transform (HHT). Consisted by RFID tag chip, power management circuit, MCU and accelerometer, the developed RFID sensor tag is used to acquire and wirelessly transmit the vibration signal. A customized power management including solar panel, low dropout (LDO) voltage regulator, supercapacitor and corresponding charging circuit is presented to guarantee constant DC power for the sensor tag. An improved band restricted empirical mode decomposition (BREMD) which is optimized by quantum-behaved particle swarm optimization (QPSO) algorithm is proposed to deal with the raw vibration signal. Compared with traditional methods, this improved BREMD method shows great superiority in reducing mode aliasing. Then, a promising fault diagnosis approach on the basis of Hilbert marginal spectrum variations is brought up. The measured results show that the presented power management circuit can generate 2.5V DC voltage for the rest of the sensor tag. The developed sensor tag can achieve a reliable communication distance of 17.8m in the test environment. Furthermore, the measurement results indicate the promising performance of fault diagnosis for transformer.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2009.05a
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• pp.190-195
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• 2009

자동차 이용자 수가 증가 할수록 자동차 사고로 인한 피해도 많이 늘어나고 있다. 이러한 자동차 사고를 사전에 예방하기 위해서는 운전자의 상태 및 현재 차량 상태를 파악하여 사고를 미리 방지함으로서 운전자의 안전을 보조할 수 있는 시스템이 필요하다. 본 연구에서는 안전운전을 보조하기 위하여 졸음운전 여부 감지 시스템, 후진시 후방 안전거리를 감지하는 시스템, 쾌적한 운전 환경을 위한 실내 환경 측정 시스템, 주차 시 생길 수 있는 사고에 대한 감시시스템을 센서와 MCU등을 이용한 임베디드 시스템을 구현 하였다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1413-1414
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• 2015

본 연구에서는 다중압력센서를 이용하여 발바닥에 가해지는 압력을 이용하여 보행패턴 추정에 관한 기초연구를 진행하였다. 실험은 압력센서가 3개일 때와 4개일 때 두 번에 걸쳐서 실험을 진행하였다. 이때 압력센서는 flexible하며 0~5V에서 구동하는 압력센서를 사용하였으며 발 특정부위에서 측정된 압력값들을 MCU를 이용하여 처리하였으며, 처리된 데이터를 컴퓨터에서 확인이 가능하도록 하였다.

• Journal of Digital Convergence
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• v.13 no.6
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• pp.267-273
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• 2015

Recently, a wide range of products incorporating cutting-edge technology are being introduced in various sectors of design. Belkin's WeMo or Phillips' Hue are representative examples. In this context, the color-responsive lighting bookcase is a design product that would satisfy the needs of contemporary consumers who seek entertainment in their purchases. By installing lightings that change color according to the user's behavior, this design reconceptualizes the bookcase as a source of entertainment rather than a mundane object of household furnishing. The lighting apparatus can be detached and reattached, serving as stand-alone equipment. The lighting bookcase is modularized, comprising extensions equipped with MCU (Micro Controller Unit), RGB LED and color sensors. The bookcase as a whole is extendable towards four directions up to nine units with the lighting bookcase at the center. The extended, multiple lighting bookcases are wired to receive power from the main bookcase, and are equipped with RGB LEDs but not with MCUs or color sensors. Receiving power and color signals from the main lighting bookcase, the sub-bookcases feature changing shades of color. Also, it includes IoT(internet of Things). This study is a proposal of a design product, modularized to control the shades of the bookcase lighting using these sensors.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.2
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• pp.97-105
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• 2016

Microcontrollers (MCUs) for endpoint smart sensor devices of internet-of-thing (IoT) are being implemented as system-on-chip (SoC) with on-chip instruction flash memory, in which user firmware is embedded. MCUs directly fetch binary code-based instructions through bit-line sense amplifier (S/A) integrated with on-chip flash memory. The S/A compares bit cell current with reference current to identify which data are programmed. The S/A in reading '0' (erased) cell data consumes a large sink current, which is greater than off-current for '1' (programmed) cell data. The main motivation of our approach is to reduce the number of accesses of erased cells by binary code level transformation. This paper proposes a built-in write/read path architecture using binary code inversion method based on hot-spot region detection of instruction code access to reduce sensing current in S/A. From the profiling result of instruction access patterns, hot-spot region of an original compiled binary code is conditionally inverted with the proposed bit-inversion techniques. The de-inversion hardware only consumes small logic current instead of analog sink current in S/A and it is integrated with the conventional S/A to restore original binary instructions. The proposed techniques are applied to the fully-custom designed MCU with ARM Cortex-M0$^{TM}$ using 0.18um Magnachip Flash-embedded CMOS process and the benefits in terms of power consumption reduction are evaluated for Dhrystone$^{TM}$ benchmark. The profiling environment of instruction code executions is implemented by extending commercial ARM KEIL$^{TM}$ MDK (MCU Development Kit) with our custom-designed access analyzer.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.2
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• pp.347-355
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• 2012

A biometric hardware security module is a physical device that comes in the form of smartcard or some other USB type security token is composed with biometric sensor and microcontroller unit (MCU). These modules are designed to process key generation and electronic signature generation inside of the device (so that the security token can safely save and store confidential information, like the electronic signature generation key and the biometric sensing information). However, the existing model is not consistent that can be caused by the disclosure of an ID and password, which is used by the existing personal authentication technique based on the security token, and provide a high level of security and personal authentication techniques that can prevent any intentional misuse of a digital certificate. So, this paper presents a model that can provide high level of security by utilizing the biometric security token and Public Key Infrastructure efficiently, presenting a model for privacy preserving personal authentication that links the biometric security token and the digital certificate.

• Convergence Security Journal
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• v.24 no.1
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• pp.43-49
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• 2024

The convergence of education and technology has been emphasized, leading to the application of educational technology (EdTech) in the field of education. EdTech provides learner-centered, customized learning environments through various media and learning situations. In this paper, we designed hardware for EdTech-based educational tools for IoT security education in the field of cybersecurity education. The hardware is based on a dual microcontroller unit (MCU) within a single board, allowing for both attack and defense to be performed. To leverage various sensors in the Internet of Things (IoT), the hardware is modularly designed. From an educational perspective, utilizing EdTech in cybersecurity education enhances engagement by incorporating tangible physical teaching aids. The proposed research suggests that the design of IoT security education hardware can serve as a reference for simplifying the creation of a security education environment for embedded hardware, software, sensor networks, and other areas that are challenging to address in traditional education..