• 센서학회지
• /
• 제33권1호
• /
• pp.12-17
• /
• 2024

Floating inverter amplifiers (FIAs) have recently garnered considerable attention owing to their high energy efficiency and inherent resilience to input common-mode voltages and process-voltage-temperature variations. Since the voltage gain of a simple FIA is low, it is typically cascaded or cascoded to achieve a higher voltage gain. However, cascading poses stability concerns in closed-loop applications, while cascoding limits the output swing. This study introduces a gain-enhanced FIA that features cross-coupled body biasing. Through simulations, it is demonstrated that the proposed FIA designed using a 28-nm complementary metal-oxide-semiconductor technology with a 1-V power supply can achieve a high voltage gain (> 90 dB) suitable for dynamic open-loop applications. The proposed FIA can also be used as a closed-loop amplifier by adjusting the amount of positive feedback due to the cross-coupled body biasing. The capability of achieving a high gain with minimum-length devices makes the proposed FIA a promising candidate for low-power, high-speed sensor interface systems.

• Physical Therapy Rehabilitation Science
• /
• 제6권4호
• /
• pp.189-195
• /
• 2017

Objective: The purpose of this study was to examine the effects of real-time visual feedback weight shift training during golf swinging on golf performance. Design: Repeated-measures crossover design. Methods: Twenty-sixth amateur golfers were enrolled and randomly divided into two groups: The golf swing training with real-time feedback on weight shift (experimental group) swing training on the Wii balance board (WBB) by viewing the center of pressure (COP) trajectory on the WBB. All participants were assigned to the experimental group and the control group. The general golf swing training group (control group) performed on the ground. The golf performance was measured using a high-speed 3-dimensional camera sensor which analyses the shot distance, ball velocity, vertical launch angle, horizontal launch angle, back spin velocity and side spin velocity. The COP trajectory was assessed during 10 practice sessions and the mean was used. The golf performance measurement was repeated three times and its mean value was used. The assessment and training were performed at 24-hour intervals. Results: After training sessions, the change in shot distance, ball velocity, and horizontal launch angle pre- and post-training were significantly different when using the driver and iron clubs in the experimental group (p<0.05). The interaction time${\times}$group and time${\times}$club were not significant for all variables. Conclusions: In this study, real-time feedback training using real-time feedback on weight shifting improves golf shot distance and accuracy, which will be effective in increasing golf performance. In addition, it can be used as an index for golf player ability.

• 대한물리치료과학회지
• /
• 제27권3호
• /
• pp.25-34
• /
• 2020

Background: Gait analysis is an important measurement for health professionals to assess gait patterns related to functional limitations due to neurological or orthopedic conditions. The purpose of this study was to investigate the reliability of the newly developed portable gait analysis system (PGAS). Design: Cross-sectional design. Test-retest study. Methods: The PGAS study was based on a wearable sensor, and measurement of gait kinematic parameters, such as gait velocity, cadence, step length and stride length, and joint angle (hip, knee, and ankle) in stance and swing phases. The results were compared with a motion capture system (MCS). Twenty healthy individuals were applied to the MCS and PGAS simultaneously during gait performance. Results: The test-retest reliability of the PGAS showed good repeatability in gait parameters with mean intra-class correlation coefficients (ICCs) ranging from 0.840 to 0.992, and joint angles in stance and swing phase from 0.907 to 0.988. The acceptable test-retest ICC was observed for the gait parameters (0.809 to 0.961), and joint angles (0.800 to 0.977). Conclusion: The results of this study indicated that the developed PGAS showed good grades of repeatability for gait kinematic data along with acceptable ICCs compared with the results from the MCS. The gait kinematic parameters in healthy subjects can be used as standard values for adopting this PGAS.

• Smart Structures and Systems
• /
• 제6권5_6호
• /
• pp.641-659
• /
• 2010

Structural Health Monitoring (SHM) gradually becomes a technique for ensuring the health and safety of civil infrastructures and is also an important approach for the research of the damage accumulation and disaster evolving characteristics of civil infrastructures. It is attracting prodigious research interests and the active development interests of scientists and engineers because a great number of civil infrastructures are planned and built every year in mainland China. In a SHM system the sheer number of accompanying wires, fiber optic cables, and other physical transmission medium is usually prohibitive, particularly for such structures as offshore platforms and long-span structures. Fortunately, with recent advances in technologies in sensing, wireless communication, and micro electro mechanical systems (MEMS), wireless sensor technique has been developing rapidly and is being used gradually in the SHM of civil engineering structures. In this paper, some recent advances in the research, development, and implementation of wireless sensors for the SHM of civil infrastructures in mainland China, especially in Dalian University of Technology (DUT) and Harbin Institute of Technology (HIT), are introduced. Firstly, a kind of wireless digital acceleration sensors for structural global monitoring is designed and validated in an offshore structure model. Secondly, wireless inclination sensor systems based on Frequency-hopping techniques are developed and applied successfully to swing monitoring of large-scale hook structures. Thirdly, wireless acquisition systems integrating with different sensing materials, such as Polyvinylidene Fluoride(PVDF), strain gauge, piezoresistive stress/strain sensors fabricated by using the nickel powder-filled cement-based composite, are proposed for structural local monitoring, and validating the characteristics of the above materials. Finally, solutions to the key problem of finite energy for wireless sensors networks are discussed, with future works also being introduced, for example, the wireless sensor networks powered by corrosion signal for corrosion monitoring and rapid diagnosis for large structures.

• 융합신호처리학회논문지
• /
• 제22권2호
• /
• pp.79-84
• /
• 2021

AGV에서 가장 중요한 부품은 가이드 센서이며, 이 센서의 대표적인 기능은 정밀한 주행경로 추출이다. 가이드 센서의 정밀도에 낮거나 잘못된 주행 경로를 추출한다면 AGV가 충돌하거나 AGV 제어에서 좌·우 흔들림이 발생되어 적재물이 낙하, 주행경로 이탈 등의 문제가 발생한다. 이러한 문제점을 개선하기 위해 본 연구에서는 다중 마스킹과 무게중심법을 이용한 가이드센서 신호처리 기법을 제안하고 구현하여 그 성능을 평가하였다. 그 결과, 직진경로 및 좌/우 분기 경로 추출의 평균오차가 2.32[mm]를 보였으며, 특히 기존의 무게중심법 보다 27[%]이상의 성능개선을 보였다. 이와 같이 제안된 가이드 센서 신호 처리 기법을 적용한다면 AGV 자세 제어와 주행 안정성이 향상될 것으로 사료된다.

• 센서학회지
• /
• 제19권1호
• /
• pp.25-30
• /
• 2010

This paper presents a low noise CMOS regulator for a low power capacitive sensor interface in a $0.5{\mu}m$ CMOS standard technology. Proposed LDO regulator circuit consist of a voltage reference block, an error amplifier and a new buffer between error amplifier and pass transistor for a good output stability. Conventional source follower buffer structure is simple, but has a narrow output swing and a low S/N ratio. In this paper, we use a 2-stage wide band OTA instead of source follower structure for a buffer. From SPICE simulation results, we got 0.8 % line regulation and 0.18 % load regulation.

• 센서학회지
• /
• 제15권1호
• /
• pp.1-6
• /
• 2006

We fabricated Si nano-wire MOSFET by using the conventional photolithography with a $1.5{\mu}m$ resolution. Si nano-wire was fabricated by using reactive ion etching (RIE), anisotropic wet etching and thermal oxidation on a silicon-on-insulator (SOI) substrate, and its width is 30 nm. Logarithmic circuit consisting of a NMOSFET and Si nano-wire MOSFET has been constructed for application to high-sensitivity image sensor. Its sensitivity was 1.12 mV/lux. The output voltage swing was 1.386 V.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• 제5권4호
• /
• pp.316-321
• /
• 2005

We designed and implemented fish robots for various purposes such as autonomous navigation, maneuverability control, posture balancing and improvement of quick turns in a tank of 120 X 120 X 180cm size. Typically, fish robots have 30-50 X 15-25 X 10-20cm dimensions; length, width and height, respectively. It is essential to have the ability of quick and smooth turning to avoid collision with obstacles or walls of the water pool at a close distance. Infrared distance sensors are used to detect obstacles, magneto-resistive sensors are used to read direction information, and a two-axis accelerometer is mounted to compensate output of direction sensors. Because of the swing action of its head due to the tail fin movement, the outputs of an infrared distance sensor contain a huge amount of noise around true distances. With the information from accelerometers and e-compass, much improved distance data can be obtained by fuzzy logic based estimation. Successful swimming and smooth turns without collision demonstrated the effectiveness of the distance estimation.

• 재활복지공학회논문지
• /
• 제7권2호
• /
• pp.75-84
• /
• 2013

본 연구에서는 근전도 신호를 이용하여 보행주기에 따른 패턴 및 특징을 시간영역과 주파수영역으로 나누어 분석하였다. 보행주기를 입각기와 유각기로 나누어 평지보행과 계단보행 실험을 실시하여 그 결과를 분석하였으며, 이때 시상면에서의 하퇴부 각도와 대퇴사두근과 대퇴이두근의 근전도 신호를 대상으로 하였다. 하퇴부의 기울기는 모든 보행에서 HS일 때 가장 큰 기울기 값을 나타내었으며, TO일 때 가장 낮은 값을 나타내었다. 시간영역에서의 근전도 분석은 모든 보행에서 보행주기에 따라 IEMG가 일정한 패턴을 보였으며, 보행 종류 및 주기 판단에 가장 용이할 것으로 판단된다. 주파수영역에서의 분석은 시간에 따른 주파수 분석이 가능한 STFT법을 사용하였으며, 기울기센서를 이용하여 보행주기를 구분하고자 하였다. 또한 STFT한 결과를 스펙트럼으로 나타내어 분석하였으며, 모든 보행에서 입각기가 유각기보다 더 높은 주파수를 가지는 것을 확인하였다. 본 연구를 통하여 근전도와 시상면에서의 하퇴부 기울기를 이용하여 보행주기 판단 및 분석의 가능성을 확인하였으며, 이를 활용하면 하지 절단환자의 보행의지를 판단하여 의족제어 및 효율적 재활에 기여할 수 있을 것으로 판단된다.

• 센서학회지
• /
• 제29권5호
• /
• pp.328-331
• /
• 2020

In this study, a highly crystalline SnO₂ thin film was formed using a sol-gel process. In addition, a SnO₂ thin-film transistor was successfully fabricated. The fabricated SnO₂ thin-film transistor exhibited conventional n-type semiconductor properties, with a mobility of 0.1 cm² V^-1 s^-1, an on/off current ratio of 1.2 × 10⁵, and a subthreshold swing of 2.69. The formed SnO₂ had a larger bandgap (3.95 eV) owing to the bandgap broadening effect. The fabricated photosensor exhibited a responsivity of 1.4 × 10^-6 Jones, gain of 1.43 × 10⁷, detectivity of 2.75 × 10^-6 cm Hz^1/2 W^-1, and photosensitivity of 4.67 × 10².