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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Remote Estimation of Water Storage Variation of Lakes in Tibetan Plateau Over the Past 20 Years
摘要： Changes in water storage of the lakes at the Tibetan Plateau are regarded as one of the most critical indicators of regional hydrological response to climate change. Different to the conventional hydrological approaches, in this study, we investigate the storage change of four lakes basing on a conceptual lake storage model and the most recent (2001-2016) available satellite observation that cover the lakes. The water surface areas and water levels are derived from MODIS and LEGOS altimetry data, respectively. Based on the regression function between water level and lake area, the net water budgets of the four lakes are estimated for the period. The results show that the storage of Ziling Co rose the fastest at the rate of 8.24 billion m3/a in the past decades, and the rising rate of Qinghai lake has also reached 4.5billion m3/a. The Ngoring Lake which located in the same region with Qinghai Lake changed fluctuatingly, but the water storage has risen 4.9 billion m3 from 2001 to 2016. The water storage of Dogaicoring QC increased steadily at the rate of 1.2 billion m3/a.
关键词： Lake water level – area curve,Water storage changes,Remote Sensing
更新于2025-09-04 15:30:14
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Technology Evolution and Growth Potential for Printed Electronic Papers
摘要： Electronic paper is now closer than ever to changing the way we read, write, and study. This was hailed as a revolution so profound that some see it as second only to the invention of the printing press in the 15th century. In this study, four analytical methods, which included statistical analysis, technology decomposition, multistage technological evolution and growth potential analysis were used. Results showed that technological research on business has great potential for development and vast market, and it would be another 16 years before the limit could be reached for patents. A great deal of technology breakthrough has been achieved during 1992 and 2012. The four major countries for printed electronic paper development are Japan, USA, South Korea and China. However, China has a gap compared with other countries, as the key technology was held by large enterprises. The apparatus for printed electronic paper has been the major focus in China. The key point for research on printed electronic paper was focused on devices for presentation and light emission, and related semiconductor devices.
关键词： Patent Bibliometrics,Growth Potential,Technology Evolution,S Curve,Printed Electronic Paper
更新于2025-09-04 15:30:14
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Sugar Contents and Firmness of Apples Based on Multi-Spectral Imaging Technology
摘要： The paper proposed a prediction method of apple sugar content and firmness based on multi-spectral imaging. Firstly, four characteristic wavelengths (670, 750, 780 and 810 nm) were selected by correlation coefficient method. The gray images of samples at different wavelengths were collected by multi-spectral imaging system, then fitted with Lorenz function, modified Lorenz function, Gaussian function and polynomial function, respectively. It was found that the fitting effect of modified Lorenz function was best. Therefore, the experiment was performed by multiple linear regression and partial least square regression analysis of sugar content and firmness with the fitting parameters of modified Lorenz function. The result showed that the prediction of multiple linear regression model was better than partial least squares regression model. The modeling correction correlation coefficient, calibration standard deviation, the prediction correlation coefficient and predicted standard deviation of sugar content were 0.8568, 0.6736, 0.8395 and 0.7068, respectively. The modeling correction correlation coefficient, calibration standard deviation, the prediction correlation coefficient and the predicted standard deviation of firmness were 0.8660, 0.3275, 0.8407 and 0.3555, respectively. The results also showed that this method was feasible for the prediction of apple sugar content and firmness.
关键词： Firmness,Multi-spectral imaging,Curve fitting,Apple,Multiple linear regression,Sugar content
更新于2025-09-04 15:30:14
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The Behavior of CPW-Fed Sierpinski Curve Fractal Antenna
摘要： In this paper, the behavior of Coplanar Waveguide (CPW) fed SIERPINSKI curve fractal antenna is studied. The results show that there is a relationship between the iteration number and the resonance frequencies. With increase in the number of iteration the resonance frequency decreases with a constant ratio. The use of fractal structures to design antennas makes them more miniaturized. The simulated results obtained from CADFEKO a Method of Moments (MoM) model based Solver and measurement using Vector Network Analyzer Anritsu MS2026C are in good agreement.
关键词： SIERPINSKI Curve,Fractal Antennas,Antenna design
更新于2025-09-04 15:30:14
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Automatic extraction of 3D anatomical feature curves of hip bone models reconstructed from CT images
摘要： 3D anatomical feature curves (AFC) on bone models reconstructed from CT/MRI images are important in some fields, such as preoperative planning, intra-operative navigation, patient-specific prosthesis design, etc. Interactive extraction of feature curves on patient-specific bone models is time-consuming, has low repeatability and accuracy. This paper presents a computer graphics method to automatically extract AFC from 3D hip bone models reconstructed from CT images. A DCSS (direct curvature scale space)-based technique is firstly used to extract anatomical feature points (AFP) in every contour, using anatomical structure information as prior knowledge so that AFP are extracted and only extracted. Then, corresponding AFP are linked in different contours and AFC is generated. AFC obtained by our method were compared with those interactively extracted by three surgeons, which showed that our method is feasible (Dice coefficient: 0.94; Average symmetric surface distance: 3.97 mm). The method was also applied to identify anatomical landmarks, which showed that our method is superior to the curvature-based methods that fail to identify landmark regions or have too many redundant regions, which results in failures to subsequently label landmark regions using pre-defined spatial adjacency matrices.
关键词： Anatomical,landmark,feature,hip,curve
更新于2025-09-04 15:30:14
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Influence of Sea State on Sea Surface Height Oscillation from Doppler Altimeter Measurements in the North Sea
摘要： This paper reports on an investigation on the in?uence of waves on the sea surface height error, σh, as measured by Delay Doppler satellite altimetry (DDA). CryoSat-2 altimeter sea surface height (SSH) data in the North Sea, processed in both DDA and pseudo low resolution mode (PLRM), are correlated with European Centre for Medium-Range Weather Forecasts (ECMWF) co-located sea state data. We ?nd a small, but consistent correlation between the 1 Hz standard deviation, σh, of the 20 Hz altimeter SSH and the ECMWF total signi?cant wave height, SWHt. The same analysis carried out between σh and the swell component of the wave spectrum shows a smaller correlation. In contrast, the correlation between the PLRM σh and any component of the SWH spectrum has not been found to be signi?cant. To provide an explanation of these results, the aliasing effect caused by the interaction between the sea wavelength and the altimeter resolution has been considered; a simple model has, therefore, been produced to simulate the dependence of the aliasing-derived, σA, on the sea wavelength. The alias/wavelength curve obtained helps to explain why—at least for the relatively low wavelength sea data considered—the wave direction and its wavelength have little or no in?uence on σh.
关键词： Doppler altimetry,sea surface height,sea surface height error,altimeter resolution,sea waves,aliasing curve
更新于2025-09-04 15:30:14
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Comparison of level set models in image segmentation
摘要： Image segmentation is one of the most important tasks in modern imaging applications, which leads to shape reconstruction, volume estimation, object detection and classification. One of the most popular active segmentation models is level set models which are used extensively as an important category of modern image segmentation technique with many different available models to tackle different image applications. Level sets are designed to overcome the topology problems during the evolution of curves in their process of segmentation while the previous algorithms cannot deal with this problem effectively. As a result, there is often considerable investigation into the performance of several level set models for a given segmentation problem. It would therefore be helpful to know the characteristics of a range of level set models before applying to a given segmentation problem. In this study, the authors review a range of level set models and their application to image segmentation work and explain in detail their properties for practical use.
关键词： topology problems,curve evolution,level set models,active segmentation,image segmentation
更新于2025-09-04 15:30:14
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Hilbert Curve-Based Metasurface to Enhance Sensitivity of Radio Frequency Coils for 7-T MRI
摘要： In this paper, we propose a compact, lightweight, and easy-to-fabricate Hilbert curve-based metasurface resonator that can effectively increase the sensitivity (radio frequency (RF) field intensity) and penetration depth of an RF coil for 7-T magnetic resonance imaging scanner. A circuit model is proposed to accurately calculate the resonance frequency of Hilbert curve resonators of different orders. A single element of a transverse electromagnetic (EM) coil was used for this paper. The increase in the field sensitivity introduced by the proposed metasurface to an RF coil was successfully demonstrated through simulations and experiments. The EM field produced by the RF coil is redistributed due to the presence of the proposed metasurface. The key feature of the proposed structure is its significant increase in the penetration depth of magnetic fields into the imaging volume. An enhancement of the magnetic field by more than four times was observed at 13.5 cm away from the coil experimentally. Flexibility for matching the coil integrated with the proposed surface is shown.
关键词： metasurface,magnetic resonance imaging (MRI),radio frequency (RF) coil,Hilbert curve
更新于2025-09-04 15:30:14
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Digital Tomosynthesis for Evaluating Metastatic Lung Nodules: Nodule Visibility, Learning Curves, and Reading Times
摘要： Objective: To evaluate nodule visibility, learning curves, and reading times for digital tomosynthesis (DT). Materials and Methods: We included 80 patients who underwent computed tomography (CT) and DT before pulmonary metastasectomy. One experienced chest radiologist annotated all visible nodules on thin-section CT scans using computer-aided detection software. Two radiologists used CT as the reference standard and retrospectively graded the visibility of nodules on DT. Nodule detection performance was evaluated in four sessions of 20 cases each by six readers. After each session, readers were unblinded to the DT images by revealing the true-positive markings and were instructed to self-analyze their own misreads. Receiver-operating-characteristic curves were determined. Results: Among 414 nodules on CT, 53.3% (221/414) were visible on DT. The main reason for not seeing a nodule on DT was small size (93.3%, ≤ 5 mm). DT revealed a substantial number of malignant nodules (84.1%, 143/170). The proportion of malignant nodules among visible nodules on DT was significantly higher (64.7%, 143/221) than that on CT (41.1%, 170/414) (p < 0.001). Area under the curve (AUC) values at the initial session were > 0.8, and the average detection rate for malignant nodules was 85% (210/246). The inter-session analysis of the AUC showed no significant differences among the readers, and the detection rate for malignant nodules did not differ across sessions. A slight improvement in reading times was observed. Conclusion: Most malignant nodules > 5 mm were visible on DT. As nodule detection performance was high from the initial session, DT may be readily applicable for radiology residents and board-certified radiologists.
关键词： Tomography,Learning curve,Pulmonary nodules,X-ray
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE International Students' Conference on Electrical, Electronics and Computer Science (SCEECS) - Bhopal, India (2018.2.24-2018.2.25)] 2018 IEEE International Students' Conference on Electrical, Electronics and Computer Science (SCEECS) - A Fast Global Maximum Power Point Tracking Technique for Partially Shaded PV Arrays
摘要： This paper proposes a new global MPPT method for PV array under non-uniform insolation. The proposed method first tracks the knee point using I-V characteristic which is near to the local peak of the P-V curve. Then it compares the measured power at various knee points to find the region containing global peak. Finally, it uses P&O to find the exact global peak. Thus the proposed method avoids the use of P&O to track every local peak. The performance of the proposed algorithm is further verified in MATLAB/Simulink. The results show that the proposed method is able to track global peak of PV array during Partially Shaded Conditions.
关键词： Partially shaded conditions (PSCs),Boost converter,PV system,Maximum power point tracking (MPPT),I-V curve
更新于2025-09-04 15:30:14