• International Journal of Contents
• /
• v.18 no.1
• /
• pp.17-26
• /
• 2022

With the acceleration of urbanization and industrialization, air pollution has become increasingly serious, and the pollution control situation is not optimistic. Climate change has become a major global challenge faced by mankind. To actively respond to climate change, China has proposed carbon peak and carbon neutral goals. However, atmospheric pollutants and meteorological factors that affect air quality are complex and changeable, and the complex relationship and correlation between them must be further clarified. This paper uses China's 2013-2018 high-resolution air pollution reanalysis open data set, as well as statistical methods of the Pearson Correlation Coefficient (PCC) to calculate and visualize the design and analysis of environmental monitoring big data, which is intuitive and it quickly demonstrated the correlation between pollutants and meteorological factors in the temporal and spatial sequence, and provided convenience for environmental management departments to use air quality routine monitoring data to enable dynamic decision-making, and promote global climate governance. The experimental results show that, apart from ozone, which is negatively correlated, the other pollutants are positively correlated; meteorological factors have a greater impact on pollutants, temperature and pollutants are negatively correlated, air pressure is positively correlated, and the correlation between humidity is insignificant. The wind speed has a significant negative correlation with the six pollutants, which has a greater impact on the diffusion of pollutants.

• Journal of Sensor Science and Technology
• /
• v.32 no.6
• /
• pp.432-440
• /
• 2023

This study introduces an efficient readout circuit designed for two-electrode electrocardiogram (ECG) recording, characterized by its low-noise and low-power consumption attributes. Unlike its three-electrode counterpart, the two-electrode ECG is susceptible to common-mode interference (CMI), causing signal distortion. To counter this, the proposed circuit integrates a common-mode charge pump (CMCP) with a window comparator, allowing for a CMI tolerance of up to 20 V_PP. The CMCP design prevents the activation of electrostatic discharge (ESD) diodes and becomes operational only when CMI surpasses the predetermined range set by the window comparator. This ensures power efficiency and minimizes intermodulation distortion (IMD) arising from switching noise. To maintain ECG signal accuracy, the circuit employs a chopper-stabilized instrumentation amplifier (IA) for low-noise attributes, and to achieve high input impedance, it incorporates a floating high-pass filter (HPF) and a current-feedback instrumentation amplifier (CFIA). This comprehensive design integrates various components, including a QRS peak detector and serial peripheral interface (SPI), into a single 0.18-㎛ CMOS chip occupying 0.54 mm². Experimental evaluations showed a 0.59 µV_RMS noise level within a 1-100 Hz bandwidth and a power draw of 23.83 µW at 1.8 V.

• Earthquakes and Structures
• /
• v.25 no.5
• /
• pp.385-398
• /
• 2023

The parameters of the multiple-vertical-line-element model (MVLEM) of reinforced concrete (RC) shear walls are often empirically determined, which causes large simulation errors. To improve the simulation accuracy of the MVLEM for RC shear walls, this paper proposed a novel method to determine the MVLEM parameters using the artificial neural network (ANN). First, a comprehensive database containing 193 shear wall specimens with complete parameter information was established. And the shear walls were simulated using the classic MVLEM. The average simulation errors of the lateral force and drift of the peak and ultimate points on the skeleton curves were approximately 18%. Second, the MVLEM parameters were manually optimized to minimize the simulation error and the optimal MVLEM parameters were used as the label data of the training of the ANN. Then, the trained ANN was used to generate the MVLEM parameters of the collected shear walls. The results show that the simulation error of the predicted MVLEM was reduced to less than 13% from the original 18%. Particularly, the responses generated by the predicted MVLEM are more identical to the experimental results for the testing set, which contains both flexure-control and shear-control shear wall specimens. It indicates that establishing MVLEM for RC shear walls using ANN is feasible and promising, and that the predicted MVLEM substantially improves the simulation accuracy.

• Nuclear Engineering and Technology
• /
• v.55 no.10
• /
• pp.3700-3708
• /
• 2023

The stochastic origin ensembles method with resolution recovery (SOE-RR) has been proposed to reconstruct proton-induced prompt gammas (PGs), and the reconstructed PG image was used for range verification. However, due to low detection efficiency, the number of valid events is low. Such a low-count condition can degrade the accuracy of the SOE-RR method for proton range verification. In this study, we proposed two strategies to improve the reconstruction of the SOE-RR algorithm for low-count PG imaging. We also studied the number of iterations and repetitions required to achieve reliable range verification. We simulated a proton beam (10⁸ protons) irradiated on a water phantom and used a two-layer Compton camera to detect 4.44-MeV PGs. Our simulated results show that combining the SOE-RR algorithm with restricted volume (SOE-RR-RV) can reduce the error of the estimation of the Bragg peak position from 5.0 mm to 2.5 mm. We also found that the SOE-RR-RV algorithm initialized using a back-projection image could improve the convergence rate while maintaining accurate range verification. Finally, we observed that the improved SOE-RR algorithm set for 60,000 iterations and 25 repetitions could provide reliable PG images. Based on the proposed reconstruction strategies, the SOE-RR algorithm has the potential to achieve a positioning error of 2.5 mm for low-count PG imaging.

• Journal of Medicine and Life Science
• /
• v.20 no.4
• /
• pp.166-171
• /
• 2023

Mixed urinary incontinence (UI) is common in women. This study aimed to assess the efficacy of anti-incontinence surgery in female patients with equally severe stress UI (SUI) and urge UI (UUI). All patients had equal severity of SUI and UUI. The postoperative cure rate was categorized into the cure group (CG) and failure group (FG). Postoperative satisfaction was categorized into the satisfaction group (SG) and the dissatisfaction group (DG). Statistical significance was set at P<0.05. Ninety patients (SG, 73.3%; DG, 26.7%; CG, 93.3%; FG, 6.7%) were included in the study. In the univariate analysis, body mass index (BMI), total bladder capacity, and overactive bladder symptom score (OABSS) were significantly different between the SG and DG groups. Peak urinary flow, Valsalva leak point pressure (VLPP), and OABSS were significantly different between the CG and FG groups. In the multivariate analysis, OABSS (P=0.001) and BMI (P=0.032) were independent predictors of postoperative satisfaction. VLPP (P=0.023) was the only independent factor associated with the postoperative cure rate. In equal severity of SUI and UUI, VLPP was found to be the only independent factor associated with postoperative cure rates. Higher VLPP values were associated with higher cure rates. BMI and OABSS were identified as independent predictors of postoperative satisfaction, with lower BMI and OABSS associated with higher postoperative satisfaction.

• Earthquakes and Structures
• /
• v.26 no.6
• /
• pp.489-499
• /
• 2024

Infill masonry walls are vulnerable to lateral loads, including seismic, wind, and concentrated push loads. Various strengthening metal fittings have been proposed to improve lateral load resistance, particularly against seismic loads. This study introduces the use of post-compressed wedges as a novel reinforcement method for infill masonry walls to enhance lateral load resistance. The resistance of the infill masonry wall against lateral-concentrated push loads was assessed using an out-of-plane push-over test on specimens sized 2,300×2,410×190 mm³. The presence or absence of wedges and wedge spacing were set as variables. The push-over test results showed that both the unreinforced specimen and the specimen reinforced with 300 mm spaced wedges toppled, while the specimen reinforced with 100 mm spaced wedges remained upright. Peak loads were measured to be 0.74, 29.77, and 5.88 kN for unreinforced specimens and specimens reinforced with 100 mm and 300 mm spaced wedges, respectively. Notably, a tighter reinforcement spacing yielded a similar strength, as expected, which was attributed to the increased friction force between the masonry wall and steel frame. The W-series specimens exhibited a trend comparable to that of the displacement ductility ratio. Overall, the findings validate that post-compressed wedges improve the out-of-plane strength of infill masonry walls.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.49 no.4
• /
• pp.291-298
• /
• 2023

In this study, a quantitative analysis method was developed using high-performance liquid chromatography (HPLC) to analyze the content of ceramide NP in lotion, cream, and cleanser formulations in cosmetics. The analysis was performed using a C18 column, and the mobile phase was set at a ratio of 70 : 30 for acetonitrile and methanol, the flow rate was set to 0.8 mL/min, and the column temperature was set to 20 ℃. The method was verified by analyzing specificity, linearity, limit of detection, limit of quantitation, accuracy, and precision in accordance with the ICH guidelines. As a result of validating the method, the linearity of the calibration curve was excellent (R² = 0.99984). The accuracy of the lotion, cream, and cleanser formulations was confirmed with a recovery rate ranging from 95.11% to 100.48%. The precision analysis showed a low relative standard deviation (RSD) of less than 0.26%. The limit of detection was 0.902 ㎍/mL, and the limit of quantitation was 2.733 ㎍/mL. Through this quantitative analysis method of ceramide NP applied in cosmetics, it is expected to assist in the quality control of products by enabling measurement even when it is difficult to separate the main peak due to the influence of interfering substances.

• Journal of the Korean Geographical Society
• /
• v.50 no.6
• /
• pp.571-605
• /
• 2015

This research revealed that 'Yipjiamlyu' in the Mukedeng's map is geographically 'a beginning point of underf low,' whose location is on the Heishigou's riverbed(E.L. 1,840m) in the NNE side of Daegakbong peak, and that 'Tomungangweon'(Heishigou) is one of the upstream reach of the Sungari River, which, according to historical documents and my fieldwork, Mukedeng also knew at the time of Yimjin(1712) Boundary Making and Demarcation(YBMD). These findings suggest the need to reinterpret the processes of YBMD. Mukedeng set up the Baekdusanjeonggyeobi on the mistaken assumptions on the linkage of 'Yipjiamlyu' and Tumen River. It should have been set up on the Daeyeonjibong peak. Mukedeng found the 'Yipjiamlyu' on the riverbed of 'Tomungangweon'(Heishigou), went downstream, and realized that this river did not flow into the Tumen River. During the search for the source of Tumen River, he found a water stream, and regarded it as the source of Tumen River. He speculated that the water at the 'Yipjiamlyu' flows through the underground to reappear at the his 'identified' source of Tumen River. Consequently, he adjured the construction of demarcation from Baekdusanjeonggyeobi through 'Yipjiamlyu' to the his 'identified' source of Tumen River. The water stream pointed as the source of Tumen River, however, was not part of the upstream reach of Tumen River. Actually, Korean officials, who were in charge of establishing boundary features, set up the demarcation from Baekdusanjeonggyeobi through Huanghuasongdianzi to the true source of Tumen River identified by themselves, which Mukedeng had not intended. The ambiguity of the location of 'Yipjiamlyu' caused a difference between Mukedeng's original request and Korean officials' implementation in the boundary demarcation. Throughout the whole processes of YBMD, Korea(Joseon) and China(Qing) both mistook the real geography of the river system. Their understanding on Yalu River system was correct. But the identification of the spring source of the Tumen River by Korean participants was the only geographically correct result related on this river system in YBMD.

• Journal of KIISE:Software and Applications
• /
• v.30 no.5_6
• /
• pp.444-453
• /
• 2003

Recently, a great interest of bio-technology(BT) is concentrated and the image analysis technique for electrophoresis gels is highly requested to analyze genetic information or to look for some new bio-activation materials. For this purpose, the location and quantity of each band in a lane should be measured. In most of existing techniques, the approach of peak searching in a profile of a lane is used. But this peak is improper as the representative of a band, because its location does not correspond to that of the brightest pixel or the center of gravity. Also, it is improper to measure band quantity in most of these approaches because various enhancement processes are commonly applied to original images to extract peaks easily. In this paper, we adopt an approach to measure accumulated brightness as a band quantity in each band region, which Is extracted by not using any process of changing relative brightness, and the gravity center of the region is calculated as a band location. Actually, we first extract lanes with an entropy-based threshold calculated on a gel-image histogram. And then, three other methods are proposed and applied to extract bands. In the MER method, peaks and valleys are searched on a vertical search line by which each lane is bisected. And the minimum enclosing rectangle of each band is set between successive two valleys. On the other hand, in the RG-1 method, each band is extracted by using region growing with a peak as a seed, separating overlapped neighbor bands. In the RG-2 method, peaks and valleys are searched on two vertical lines by which each lane is trisected, and the left and right peaks nay be paired up if they seem to belong to the same band, and then each band region is grown up with a peak or both peaks if exist. To compare above three methods, we have measured the location and amount of bands. As a result, the average errors in band location of MER, RG-1, and RG-2 were 6%, 3%, and 1%, respectively, when the lane length is normalized to a unit value. And the average errors in band amount were 8%, 5%, and 2%, respectively, when the sum of band amount is normalized to a unit value. In conclusion, RG-2 was shown to be more reliable in the accuracy of measuring the location and amount of bands.

• The Journal of Korean Academy of Prosthodontics
• /
• v.49 no.4
• /
• pp.316-323
• /
• 2011

Purpose: The purpose of this study was to investigate the effect of different thread designs on the marginal bone stresses around dental implant. Materials and methods: Standard ITI implant(ITI Dental Implant System; Straumann AG, Waldenburg, Switzerland), 4.1 mm in diameter and 10 mm in length, was selected as control. Test implants of four different thread patterns were created based on control implant, i.e. maintaining all geometrical design of control implant except thread pattern. Four thread designs used in test implants include (1) small V-shape screw (model A), (2) large V-shape screw (model B), (3) buttress screw (model C), and (4) trapezoid screw (model D). Surface area for unit length of implant was 14.4 $mm^2$ (control), 21.7 (small V-shape screw), 20.6 (large V-shape screw), 17.0 (buttress screw) and 28.7 $mm^2$ (trapezoid screw). Finite element models of implant/bone complex were created using an axisymmetric scheme with the use of NISA II/DISPLAY III (Engineering Mechanics Research Corporation, Troy, MI, USA). A load of 100 N applied to the central node on the crown top either in parallel direction or at 30 degree to the implant axis (in order to apply non-axial load to the implant NKTP type 34 element was employed). Quantification and comparison of the peak stress in the marginal bone of each implant model was made using a series of regression analyses based on the stress data calculated at the 5 reference points which were set at 0.2, 0.4, 0.6, 0.8 and 1.0 mm from implant wall on the marginal bone surface. Results: Results showed that although severe stress concentration on the marginal bone cannot be avoided a substantial reduction in the peak stress is achievable using different thread design. The peak marginal bone stresses under vertical loading condition were 7.84, 6.45, 5.96, 6.85, 5.39 MPa for control and model A, B, C and D, respectively. And 29.18, 26.45, 25.12, 27.37, 23.58 MPa when subject to inclined loading. Conclusion: It was concluded that the thread design is an important influential factor to the marginal bone stresses.