nils-herrmann/clean_scirepeval huggingface dataset:
Numerical Simulation of Electromagnetic and Thermal Stress in REBaCuO Superconducting Ring and Disk Bulks Reinforced by Stainless Steel Ring With Various Widths During Field-Cooled Magnetization

The mechanical stress of the electromagnetic hoop stress, <inline-formula><tex-math notation="LaTeX">$\sigma _{\theta }^{\text{FCM}}$</tex-math></inline-formula>, during field-cooled magnetization (FCM) from 20 T, and the thermal hoop stress, <inline-formula><tex-math notation="LaTeX">$\sigma _{\theta }^{\text{cool}}$</tex-math> </inline-formula>, under cooling, in REBaCuO disk and ring bulks reinforced by stainless steel (SUS) ring with various widths, were calculated using numerical simulations. The reinforcement effect of the SUS ring was investigated for each bulk. For the ring bulk, the maximum of <inline-formula><tex-math notation="LaTeX">$\sigma _{\theta }^{\text{FCM}}$</tex-math></inline-formula> was reduced with increasing SUS ring width, from 216 MPa for without SUS ring reinforcement, down to 93 MPa for using SUS ring with 20 mm in width, was less than that of the disk bulk. The numerical results showed that the stress concentration in the ring bulk could be alleviated by the SUS ring reinforcement. We suggest that the width of SUS ring needs to be at least 10 mm to prevent the fracture behavior of the bulk. The optimal design of the reinforcement ring should be constructed so that the total hoop stress, <inline-formula><tex-math notation="LaTeX">$\sigma _{\theta }^{\text{total}}\,(=\sigma _{\theta }^{\text{FCM}}\,+ \,\sigma _{\theta }^{\text{cool}})$</tex-math></inline-formula>, could be less than the fracture strength of the bulk during FCM.
Foreground segmentation with single reference frame using iterative likelihood estimation and graph-cut

This paper introduces a new foreground segmentation method. In contrast to most of the related works, our method uses only two image frames, a target frame to process, and a single reference frame. Our method first conducts simple thresholding like background subtraction, but then applies an iteration scheme we propose to estimate the pixel-wise likelihood of belonging to the foreground/background from the frame-to-frame difference. Finally, a further refinement considering edges is applied using graph-cut optimization. Experimental results show the effectiveness of our method, especially in that it keeps good performance over a wide range of the threshold value. That consistent performance will become an important step toward fully-automatic segmentation.
Index profile design for high-bandwidth W-shaped plastic optical fiber

Modal dispersion in plastic optical fibers with W-shaped refractive index profiles (W-shaped POFs) is investigated. The authors focus on the effect of the refractive index valley at the boundary of core and cladding on the group delay. In this paper, particularly, the relationship between the depth of the index valley and the modal dispersion is highlighted. In order to analyze the relationship precisely, the authors prepare the W-shaped POFs with a high numerical aperture (NA /spl sim/ 0.25), which are expected to show the effect of W-shaped profile more clearly than the W-shaped POFs with an NA of 0.2. As a result, the modal dispersion is strongly dependent on the depth of the index valley, which means that the control of the index valley is required, in order for minimum modal dispersion. Furthermore, by evaluating the output pulsewidth from the W-shaped POFs, the authors design the optimum index valley for the maximum bandwidth performance.
Super-resolution with Adaptive Pixel Weighting Scheme and Its Application to Super-resolved Free-Viewpoint Image Synthesis

The objective of reconstruction-based super-resolution is to construct a high-resolution image from a sequence of low-resolution images. The super-resolution processing requires precise registration of low-resolution images and the registration error degrades the resulting high-resolution image. In order to handle inaccuracies in registration, the robust super-resolution methods have been proposed. We propose an adaptive pixel weighting method which uses pixel weighting variables for the input pixels. The proposed method is the extension of the conventional pixel selection type robust super-resolution. We define the cost function which includes the regularization term for the weighting variables and the cost function is minimized against the weighting variables and the resulting HR image simultaneously. We confirmed the effectiveness of the proposed method with super-resolved free-viewpoint image synthesis.
Acquisition and processing of Ray-Space/Light Field data

Ray-Space/Light Field is a novel representation of 3-D visual information that enables 3D/free-viewpoint photo-realistic image generation. Although it is based on a clear and simple concept, and hence, it is expected to be a basic representation for 3D end-to-end systems, it has the problem that there exists no easy way to obtain Ray-Space data efficiently. In this paper, we first describe the basic concept of the Ray-Space and then review several acquisition methods, including a high number of multi-camera systems and space/time division acquisition methods. Among them, we focus on a Light Field Camera (LFC), which is capable of obtaining 4-D light ray data in a single shot using the space division method. We point out that one of the drawbacks of this system is the low resolution of the reconstructed images and introduce our approach to solve this by using a super-resolution method. Some preliminary experimental results are provided in the paper.
A study on memorability and shoulder-surfing robustness of graphical password using DWT-based image blending

Graphical passwords are an authentication method that uses pictures as passwords instead of using alphanumeric characters. We propose a graphical password method which is difficult to steal original pass-image by using characteristics of human vision system. In our method, we combine low frequency components of a decoy picture with high frequency components of a pass-image. It is easy for legitimate users to recognize the pass-image in the blended image. On the other hand, this task is difficult for attackers. We used discrete wavelet transform (DWT) to blend a decoy image and a pass-image. User studies are conducted to evaluate memorability and shoulder-surfing robustness of this method. We also compared our method with other existing methods in terms of the authentication time and the success ratio by the user test. The results show that our method is more usable and secure against shoulder-surfing.
Overcomplete compressed sensing of ray space for generating free viewpoint images

Free Viewpoint Image (FVI) technique has gained a great popularity because it enables people to freely choose the viewpoints from which they watch the targets and scenes. Generation of FVI requires all the information of a 3-D virtual space. Ray space is a direct representation of complete 3-D information, and FVIs can be generated simply by cutting ray space. However, in the straightforward construction of a ray space, a numerous number of images have to be captured in advance which triggered data explosive from data acquisiton to data storage and transmission. In this paper, we focus on compressed sensing to sparsely capture a ray space at encoder and reconstruct it at decoder. Specifically, we propose to adopt overcomplete dictionaries which are produced by learning methods, to sparsely represent the ray space data. Experimental results show that the proposed dictionary is much better than the structured dictionary in previous work or orthogonal basis in terms of the reconstruction quality of the ray space from compressively sensed data.
Free viewpoint video generation system using visual hull

Free viewpoint video technology can be used for visualization of a 3-D scene from arbitrary viewpoints, and has potential application in broadcasting of sport events. The target of our study is 3-D reconstruction of sport events from multi-view videos that were taken with several cameras sparsely arranged around players. To improve the image quality of free viewpoint video, we have introduced a reconstruction method of 3-D voxel model combining object silhouettes and photo-consistency. Moreover, we propose a method that determines the color of each voxel depending on the viewing direction without explicitly handling occlusions among the voxels. More specifically, we adopt a robust curve fitting method using Fourier series to correctly capture the color changes of each voxel along the direction from which it is seen.
Trapped Field Enhancement of a Thin, High-Jc MgB2 Bulk Without Flux Jumps Using Pulsed Field Magnetization With a Split-Type Coil With a Soft Iron Yoke

We have investigated the suppression of flux jumps and the enhancement of trapped field on a thin, high-Jc MgB2 bulk (30 mm in diameter and 7 mm in thickness) for the pulsed field magnetization (PFM) using a split-type coil with a soft iron yoke, and compared the results to those magnetized using the split-type coil without a yoke and a solenoid-type coil with a yoke. A maximum-trapped field, Bz, of 0.71 T at 14 K was achieved on the bulk surface without flux jumps by using the split coil with yoke. On the other hand, low Bz values with flux jumps were observed for the cases using the split-type coil without a soft iron yoke, and the solenoid-type coil with a yoke. These results reproduce previous ones for a thick, high-Jc MgB2 bulk (22 mm in diameter and 15 mm in thickness), for which the trapped field was enhanced to a record high value of Bz = 1.10 T at 13 K by PFM using the split-type coil with a yoke.
Estimating the life of stationary lithium-ion batteries in use through charge and discharge testing

When stationary lithium-ion batteries are used as a telecommunications backup power supply system, they need to be linked in series to achieve -48 V, and serially-connected lines must be connected in parallel to ensure capacity. To improve the reliability of a system, we must reduce the number of parallel lines. Therefore, we have developed a large capacity 200 Ah battery. We have also improved the safety of large capacity cells by using an electrolyte containing a phosphazene-based flame retardant. As a result, the cells have passing various safety standards, verifying their safety. Batteries for a backup power supply system must remain in a high state of charge (SOC). Generally, high SOC leads to battery capacity deterioration. Therefore, we fabricated with a cathode material in which part of the elemental manganese was replaced with [magnesium-spinel oxide?] and have succeeded in suppressing the capacity deterioration even in environments with almost full charge by constant voltage charging. We have also developed a battery management system for connecting the cells in a multi-series-parallel arrangement. This system has various functions such as the monitoring of various voltages and current temperatures, data backup when a fault is detected, and a safety shutdown function to control reserve batteries. We have implemented life estimation by a charge and discharge test using a backup power supply system that employs these lithium-ion batteries. Several factors affect battery life. Well known examples are the number of charge and discharge cycles, running time, temperature, difference in capacity between modules, and charge voltage. By using stationary batteries for backup, the number of charge/discharge cycles is small and the maintained charge voltage is constant. Therefore, we evaluated the difference in capacity between modules and running time and estimated battery life by charge/discharge testing. The test result shows that the developed backup system's life can be estimated by using square root law. Use of the square root law resulted in prediction of expected lifetimes of at least ten years.
Super-resolution image synthesis using the physical pixel arrangementofalight field camera

We propose a method for super-resolution image synthesis that accurately handles the physical pixel arrangement of a light field (plenoptic) camera. We use a Lytro camera to obtain 4D light field data (a set of multi-viewpoint images) through a micro-lens array. The light field data are multiplexed on a single image sensor, and thus, the data is first de-multiplexed into a set of multi-viewpoint (sub-aperture) images. However, the de-multiplexing process usually involves interpolation of the original data such as demosaicing for a color filter array and pixel resampling for the non-square micro-lens arrangement. During this interpolation, some information is added or lost to/from the original data. In contrast, our method can preserve the originally captured data as they are, and directly use them for the super-resolution image synthesis, where the super-resolved image and the corresponding depth map are alternatively refined. We experimentally demonstrate that our method can achieve higher image quality than that with a standard Light Field Toolbox.
Least MSE Regression for View Synthesis

View synthesis is the process of combining given multi-view images to generate an image from a new viewpoint. Assuming that each pixel of the new view is obtained as the weighted sum of the corresponding pixels from the input views, we focus on the problem of how to optimize the weight for each of the input views. Our weighting method is called least mean squared error (MSE) regression because it is formulated as a regression problem in which second order statistics among the viewpoints are exploited to minimize the MSE of the resulting image. More specifically, the affinity across the viewpoints is represented as a covariance and approximated using a linear model whose parameters are adapted for each dataset. By using the approximated covariance, the optimal weights can be successfully estimated. As a result, the weights derived using our method are data dependent and significantly differ from those obtained using current empirical methods such as distance penalty. Our method is still effective if the given correspondence is not completely accurate due to noise. We report on experimental results using several multi-view datasets to validate our theory and method.
Magnetic Field Design of Dipole Magnet Wound With Coated Conductor Considering Its Current Transport Characteristics

When designing accelerator magnets using high Tc superconductor tapes, their current transport characteristics with anisotropic magnetic field dependence as well as their temperature dependence must be considered. The current transport characteristics of commercially-available GdBa2Cu3O7 coated conductor made by IBAD and PLD process were measured in various magnetic fields and temperatures, and they were formulated with the percolation depinning model. Using the formulated current transport characteristics, dipole magnets wound with coated conductors were designed to show the feasibility of accelerator magnets operated at a high temperature, where cryo-coolers can be applied. First, a two-dimensional magnet cross-section was designed, and, then, a three-dimensional magnet design was made, based on the constant perimeter restriction and considering the bending and torsion tolerances of coated conductors. Their enthalpy margins, temperature margins, and current margins were estimated and they were compared with that of a NbTi magnet.
Super-resolution plane sweeping for free-viewpoint image synthesis

Free-viewpoint image synthesis (FVIS) refers to the process of generating novel viewpoint images from a set of multi-view images. Most of the conventional FVIS methods were based on image blending, so that they are subject to a fundamental limitation in resolution: the output resolution is lower than or at most equal to that of the input images. A reasonable approach to overcome this limitation is to replace image blending with reconstruction-based super-resolution. Following this idea, we propose a new FVIS method named as super-resolution plane sweeping by extending general plane sweeping methods. We also propose an adaptive weighting scheme to make super-resolution reconstruction operate only on the pixels where it improve the quality. Experimental results with real images are presented to show the effectiveness of our method.
Development of the battery fluid leak detection system for UPS

Lead acid battery is the most popular as a backup power source for communication services. It's very rare, but there is a possibility of electrolyte leakage from inside of lead acid batteries by such as manufacturing defects. If leakage from battery occurs, a ground fault accident occurs, and may cause serious accidents. Since communication service is one of a key infrastructure in our life, it is necessary to prevent such serious accidents. This paper reports about a ground fault detector that we have developed for lead acid batteries.
Real-Time All-in-Focus Video-Based Rendering Using A Network Camera Array

We present a real-time video-based rendering system using a network camera array. Our system consists of 64 commodity network cameras that are connected to a single PC through a Gigabit Ethernet. To render a high-quality novel view, we estimate a view-dependent per-pixel depth map in real-time by using a layered representation. The rendering algorithm is fully implemented on a GPU, which allows our system to efficiently use CPU and GPU independently and in parallel. Using QVGA input video resolution, our system renders a free-viewpoint video at up to 30 fps depending on rendering parameters. Experimental results show high-quality images synthesized from various scenes.
Disparity estimation from light fields using sheared EPI analysis

Structure tensor analysis on epipolar plane images (EPIs) is a successful approach to estimate disparity from a light field, i.e. a dense set of multi-view images. However, the disparity range allowable for the light field is limited, because the estimation becomes less accurate as the range of disparities become larger. To overcome this limitation, we propose a new method called sheared EPI analysis, where EPIs are sheared before the structure tensor analysis. The results of analysis obtained with different shear values are integrated into a final disparity map. As verified by extensive evaluations on 12 datasets with large disparity ranges, our method is comparably accurate to and much faster than a multi-view stereo method.
Theoretical model and optimal prefilter for view interpolation

This paper discusses a view interpolation problem where a new view would be synthesized at the midst of two parallel views. We first introduce a new theoretical model that describes the relation between accuracy of disparities and the quality of the interpolated view. Then, we derive the optimal prefilter that minimizes the power of errors on the interpolated view. Our approach is inspired by the rate-distortion theory for video coding, and can be also regarded as an attempt to reconsider the plenoptic sampling theory. Finally, we present numerical simulations and experimental results to validate our theory.
Novel procedure to improve LDMOS ESD characteristics by optimizing drain structure

Novel procedure to realize a high ESD robustness with small variation for 40V p-ch LDMOS is proposed. By optimizing the drain structure, current flow path detaches from highest electric field point during ESD events, which leads to improve both HBM robustness and its variation. By using this procedure, the device length (the length between drain and source contact) increase could be suppressed from 37 % to 8 % compared with another approach which introduced ballast resistance in the drain. The studied 40V p-ch LDMOS achieved over 6200 V HBM performance keeping the drain-source breakdown voltage (|BVdss|) over 46 V.
A structural similarity assessment for generating hybrid images

We discuss a structural similarity evaluation method in order to generate hybrid images for graphical password. The hybrid image consists of two images. One is edge information of a key image and the other is coarse features of a decoy image. Visibility of the hybrid image depends on the viewing distance and the structural similarity of the images. This property of the hybrid image is useful for preventing shoulder-surfing of graphical password. However, an evaluation method for checking whether the decoy image is appropriate to overlay the key image has not been established. To address this issue, we utilize Speeded Up Robust Features (SURF) to evaluate structural similarity between two images. Simulation results show that our similarity measure mostly coincides with the visibility of a key image. We also compare our objective metric with the structural similarity (SSIM) index and subjective scores obtained from a user test based on Scheffe's method of paired comparisons.
Performance analysis on multi-view coding with depth map distortion

Multi-view video plus depth (MVD) representations have been studied for 3-D TV and free-viewpoint video applications. In this paper, I quantitatively analyze the effect of depth map distortion on the performance of prediction-based multi-view coding. A new metric of this effect is proposed based on the rate-distortion theory, and successfully applied to both real image data and a theoretical model of view-synthesis prediction. This study reveals the types of images that are more/less sensitive to depth map distortion, which will be useful for designing/optimizing MVD coding schemes.
Frequency domain simulation of conducted EMI in power electronic converters considering internal near field couplings by FEM

Power electronic components such as busbars, capacitors, and inductors are positioned close to each other when designing a high power density converter. Therefore, the internal near field couplings between these components should be considered when designing a low electromagnetic interference (EMI) converter. In this paper, we propose a new frequency domain model for simulation of EMI in power electronic converters. We focused on frequency domain simulation to assess the internal couplings by finite element method (FEM) full wave simulation without requiring a complicated equivalent circuit model. In order to simulate both the transient voltage noise (dv/dt noise) and transient current noise (di/dt noise), we used two noise source models (a voltage source noise model and a current source noise model). We compared the measured and simulated EMI to confirm the validity of our model, and found good agreement.
A study on EGG affected by viscosity and shear rate dependence of fluid and semi-solid diets

The purpose of this study is to clarify the relation among the viscosity values of semi-solid diets and the electrical mechanism of gastric motility. Firstly, a measurement procedure suitable for stomach physiology was proposed. A new measurement procedure lessened the psychological and physiological burdens of the subjects, and controlled the cycle of gastric activity of the subjects. And the dispersion of data for subjects was decreased by this new method, in which the measurements were started after 4 hours fasting. Secondly, we prepared five grades of viscosities of fluid to semi-solid diets from low to high viscosity (30 mPa·s ~ 20000 mPa·s) mixed by five different amounts of two kinds of thickening agents. The measurements were performed for 8 healthy volunteer subjects. By evaluating DPr (Dominant Power ratio: Ratio of post/pre-prandial DP values), a significant increment by ingestion of high viscosity semi-solid diets was confirmed in both kinds of thickening agents. DFD (Dominant Frequency Dispersion) was significantly decreased in both high viscosity semi-solid diets. Thus, these results suggested that gastric activity was physiologically stimulated and the cycle of gastric activity became stable by ingestion of high viscosity diets. The results showed that an electrophysiological phenomenon in the evaluation of electrogastrography (EGG) is affected by the viscosity of diets, and also suggested that the difference in the shear rate dependence of diets was not really significant to the electrical behavior of gastric motility.