• Journal of Biomedical Engineering Research
• /
• v.41 no.6
• /
• pp.247-255
• /
• 2020

Accurate diagnosis of movement disorders is important for providing right patient care at right time. In general, assessment of motor impairment relies on clinical ratings conducted by experienced clinicians. However, this may introduce subjective opinions into scoring the severity of motor impairment. Digital devices such as table PC and smart band with accelerometer can be used for more accurate and objective assessment and possibly helpful for clinicians to make right decision of patient's states. In this study, we introduce quantification algorithms of motor impairment which uses the digital data acquired during four clinical motor tests (Line drawing, Spiral drawing, Nose to finger and Hand flip tests). The step by step procedure of quantifying metrics (Tremor Frequency, Tremor Magnitude, Error Distance, Time, Velocity, Count and Period) are provided with flowchart. The effectiveness of the proposed algorithm is presented with the result from simulated data (normal, normal with tremor and slowness, poor with tremor, poor with tremor and slowness).

• Korean Journal of Materials Research
• /
• v.31 no.3
• /
• pp.132-138
• /
• 2021

Electrochromic devices (ECDs) have been drawing great attention due to their high color contrast, low power consumption, and memory effect, and can be used in smart windows, automatic dimming mirrors, and information display devices. As with other electronic devices such as LEDs (light emitting diodes), solar cells, and transistors, the mechanical flexibility of ECDs is one of the most important issue for their potential applications. In this paper, we report on flexible ECDs (f-ECDs) fabricated using an all-in-one EC gel, which is a mixture of electrolyte and EC material. The f-ECDs are compared with rigid ECDs (r-ECDs) on ITO glass substrate in terms of color contrast, coloration efficiency, and switching speed. It is confirmed that the f-ECDs embedding all-in-one gel show strong blue absorption and have competitive EC performance. Repetitive bending tests show a degradation of electrochromic performance, which must be improved using an optimized device fabrication process.

• Journal of Surface Science and Engineering
• /
• v.54 no.3
• /
• pp.119-123
• /
• 2021

SnO₂ single layer and SnO₂/Ag/SnO₂ (SAS) tri-layered films were deposited on the glass substrate by RF and DC magnetron sputtering at room temperature and then the effect of Ag interlayer on the opto-electrical performance of the films were considered. As deposited SnO₂ films show a visible transmittance of 85.5 % and a sheet resistance of 1.2×10⁴ Ω/□, the SAS films with a 15 nm thick Ag interlayer show a lower resistance of 18.8 Ω/□ and a visible transmittance of 70.6 %, respectively. The figure of merit based on the optical transmittance and sheet resistance revealed that the Ag interlayer in the SnO₂ films enhances the opto-electrical performance without substrate heating or annealing process.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.24 no.2
• /
• pp.211-218
• /
• 2021

This paper deals with the computational work to characterize the formation and pinching of a plasma in an X-pinch configuration. A resistive magnetohydrodynamic model of a single fluid and two temperature is adopted assuming a hollow conical structure in the (r,z) domain. The model includes the thermodynamic parameter of tungsten from the corrected Thomas-Fermi EOS(equation of state), determining the average ionization charge, pressure, and internal energy. The transport coefficients, resistivity and thermal conductivity, are obtained by the corrected Lee & More model and a simple radiation loss rate by recombination process is considered in the simulation. The simulation demonstrated the formation of a core-corona plasma and intense compression process near the central region which agrees with the experimental observation in the X-pinch device at Seoul National University. In addition, it confirmed the increase in radiation loss rate with the density and temperature of the core plasma.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.24 no.6
• /
• pp.153-160
• /
• 2020

Columns are one of the most critical parts of a structural system subjected to earthquake excitations. In this regard, extensive experimental studies have been conducted to evaluate the effect of fiber reinforced polymer (FRP) wrapping on the seismic performance of reinforced concrete (RC) columns. Among them, many studies focused on the behavior of circular or square RC columns strengthened with CFRP or GFRP sheets. Since the cross-sectional shape affects confinement by FRP wrapping, its strengthening effect and final damage pattern may differ with shapes. In this study, a series of cyclic tests was conducted to investigate the seismic behavior of rectangular reinforced concrete columns strengthened with basalt-based fiber reinforced polymer (BFRP) sheets and composite fiber panels. The result shows that the effect of strengthening is not significant, and it implies a little increase of confinement by BFRP sheets and composite fiber panels, which is considered partly due to the cross-sectional shape of the columns.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.21 no.4
• /
• pp.189-198
• /
• 2021

This paper introduces the ball tracking system using image processing. The recent growth of the amateur futsal market has also raised requests for an analysis of amateur players' performance. Sports game analysis services for feedback and growth to athletes or teams are provided in various ways in various sports fields. However, the cost and spatial constraints of sports analysis services make it difficult for providing analysis services to amateur athletes. In this paper, we study and develop a ball tracking algorithm for analyzing futsal game based on the match filming service previously provided in the amateur futsal field. This allows the analysis of the match based on existing services.

• Journal of Surface Science and Engineering
• /
• v.55 no.2
• /
• pp.91-95
• /
• 2022

ZnO single layer (60 nm thick) and ZnO with Ag interlayer (ZnO/Ag/ZnO; ZAZ) films were deposited on the glass substrates by using radio frequency (RF) and direct current (DC) magnetron sputter to evaluate the effectiveness of Ag interlayer on the optical visible transmittance and the conductivity of the films. In the ZAZ films, the thickness of ZnO layers was kept at 30 nm, while the Ag thickness was varied as 5, 10, 15 and 20 nm. In X-ray diffraction (XRD) analysis, ZnO films show the (002) diffraction peak and ZAZ films also show the weak ZnO (002) peak and Ag (111) diffraction peak. As a thickness of Ag interlayer increased to 20 nm, the grain size of the Ag films enlarged to 11.42 nm and the optical band gap also increased from 4.15 to 4.22 eV with carrier concentration increasing from 4.9 to 10.5×10²¹ cm^-3. In figure of merit measurements, the ZAZ films with a 10 nm thick Ag interlayer showed the higher figure of merit of 4.0×10^-3 Ω^-1 than the ZnO single layer and another ZAZ films. From the experimental result, it is assumed that the Ag interlayer enhanced effectively the opto-electrical performance of the ZAZ films.

• Journal of Powder Materials
• /
• v.29 no.1
• /
• pp.14-21
• /
• 2022

In the powder bed fusion (PBF) process, a 3D shape is formed by the continuous stacking of very fine powder layers using computer-aided design (CAD) modeling data, following which laser irradiation can be used to fuse the layers forming the desired product. In this method, the main process parameters for manufacturing the desired 3D products are laser power, laser speed, powder form, powder size, laminated thickness, and laser diameter. Stainless steel (STS) 316L exhibits excellent strength at high temperatures, and is also corrosion resistant. Due to this, it is widely used in various additive manufacturing processes, and in the production of corrosion-resistant components with complicated shapes. In this study, rectangular specimens have been manufactured using STS 316L powder via the PBF process. Further, the effect of heat treatment at 800 ℃ on the microstructure and hardness has been investigated.

• Korean Journal of Materials Research
• /
• v.32 no.10
• /
• pp.435-441
• /
• 2022

We report the synthesis and gas sensing properties of bare and ZnO decorated TeO₂ nanowires (NWs). A catalyst assisted-vapor-liquid-solid (VLS) growth method was used to synthesize TeO₂ NWs and ZnO decoration was performed using an Au-catalyst assisted-VLS growth method followed by a subsequent heat treatment. Structural and morphological analyses using X-ray diffraction (XRD) and scanning/transmission electron microscopies, respectively, demonstrated the formation of bare and ZnO decorated TeO₂ NWs with desired phase and morphology. NO₂ gas sensing studies were performed at different temperatures ranging from 50 to 400 ℃ towards 50 ppm NO₂ gas. The results obtained showed that both sensors had their best optimal sensing temperature at 350 ℃, while ZnO decorated TeO₂ NWs sensor showed much better sensitivity towards NO₂ relative to a bare TeO₂ NWs gas sensor. The reason for the enhanced sensing performance of the ZnO decorated TeO₂ NWs sensor was attributed to the formation of ZnO (n)/ TeO₂ (p) heterojunctions and the high intrinsic gas sensing properties of ZnO.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.23 no.4
• /
• pp.107-113
• /
• 2023

This paper proposes a method for detecting smoking behavior in images using artificial intelligence technology. Since smoking is not a static phenomenon but an action, the object detection technology was combined with the posture estimation technology that can detect the action. A smoker detection learning model was developed to detect smokers in images, and the characteristics of smoking behaviors were applied to posture estimation technology to detect smoking behaviors in images. YOLOv8 was used for object detection, and OpenPose was used for posture estimation. In addition, when smokers and non-smokers are included in the image, a method of separating only people was applied. The proposed method was implemented using Google Colab NVIDEA Tesla T4 GPU in Python, and it was found that the smoking behavior was perfectly detected in the given video as a result of the test.