nils-herrmann/clean_scirepeval huggingface dataset:
Small Aircraft RF Interference Path Loss

Interference to aircraft radio receivers is an increasing concern as more portable electronic devices are allowed onboard. Interference signals are attenuated as they propagate from inside the cabin to aircraft radio antennas mounted on the outside of the aircraft. The attenuation level is referred to as the interference path loss (IPL) value. Significant published IPL data exists for transport and regional category airplanes. This report fills a void by providing data for small business/corporate and general aviation aircraft. In this effort, IPL measurements are performed on ten small aircraft of different designs and manufacturers. Multiple radio systems are addressed. Along with the typical worst-case coupling values, statistical distributions are also reported that could lead to better interference risk assessment.
Highly efficient resonant antennas for terahertz photomixers

This paper presents antenna structures suitable for terahertz photomixer designs. Two antenna structures are selected: a four-leaf-clover-shaped antenna on an extended hemispherical substrate lens and a full-wavelength dipole antenna on a thin substrate with backside excitation. The input impedance and radiation characteristics of each antenna are different, being affected by both the antenna shape and the substrate geometry. In addition, the bias line structure, which is indispensable in a THz photomixer antenna design, has a substantial effect on antenna performance, and a thorough understanding of its characteristics is necessary. Each antenna design will be presented in turn and some challenges facing antenna design will be discussed.
Loss-Tolerant Allpass-Based Filter Bank Design Suitable for Integrated Optics

This paper presents a novel design algorithm for a filter bank structure that is suitable for photonic integrated circuits. The proposed design is entirely based on the principle of loss-exhibiting allpass filtering, which is a behavior naturally observed in a variety of microscale optical components. The setup and mathematical optimization of the system is explored in detail from a signal processing perspective, and an algorithm based on convex and nonlinear optimization techniques is subsequently presented. The algorithm methodologically utilizes the otherwise-undesirable effect of waveguide loss to derive an allpass-based filter bank structure that is amenable to photonic implementation. The proposed structure is ideal for applications in time-stretched analog-to-digital converters, WDM network channelizers, and general optical signal multiplexers.
A perceptually-tuned block-transform-based progressive transmission image coder

A perceptually-tuned block-transform-based progressive transmission image coder is presented. The novel embedded coder features a locally adaptive perceptual masking thresholder that computes, based on the contents of the original image, the maximum amount of noise energy that can be injected at each transform coefficient that results in perceptually distortion-free still images or sequences of images. The adaptive thresholder is used as a pre-processor to a block-based embedded image coder. Perceptually normalized block-transform coefficients less than their corresponding masking thresholds can be set to zero before the normal embedded quantization and bit plane coding step. The result is a visually-tuned embedded coder which is capable of transparent coding when all bit planes are encoded. Visually insignificant coefficients are never included in the compressed bitstream. If lower bit rates are desired, the decoder and possibly the encoder simply deal with the higher bit planes of the visually significant coefficients. Excellent reconstructed image quality without annoying blocking and ringing artifacts can still be obtained at low bit rates.
Multiband Dual Spiral Stripline-Loaded Monopole Antenna

We propose a multiband antenna that exhibits a dual coupling characteristic and dual frequency operation using a dual spiral stripline-loaded monopole in conjunction with L-shaped slots in a ground plane. The slots allow the upper part of the ground plane to function as an additional monopole that resonates in concordance with the existing resonances of the upper and lower spiral stripline monopoles. As a result, the impedance band- widths are greatly enhanced while maintaining relatively good omnidirectional radiation characteristics. The proposed antenna occupies a volume of 36 times 7 times 102 mm3 including the ground plane, and the measured impedance bandwidths with VSWR < 2 simultaneously cover CDMA, GSM900, DCS1800, PCS1900, UMTS, IMT-2000, and WiMAX2350 bands. We describe the detailed antenna structure and present measurement results.
A new synthesis procedure for linear-phase paraunitary digital filter banks

In this paper, a new design algorithm is presented for a family of linear phase paraunitary filter banks with generalized filter length and symmetric polarity. A number of new constraints on the distributions of filter length and symmetry polarity among the channels are derived. In the algorithm, the lengths of the filters are gradually reduced through a cascade of lattice structures. The derivations for filter banks with even and odd number of channels are formulated in a unified form.
A model for image patch-based algorithms

An empirical study of the domain of patch-based learning algorithms for image and video processing is conducted. As patch-based algorithms are commonly used, knowledge of the properties of fixed size image patches would prove particularly useful and interesting. We are concerned with investigating the overall distribution of vectorized patches of general images. A multivariate distribution model is proposed and analyzed using various techniques, which include univariate histograms and modified k-nearest neighbors. The model is verified and an application using the distribution model is introduced and compared.
Single Image Superresolution Based on Gradient Profile Sharpness

Single image superresolution is a classic and active image processing problem, which aims to generate a high-resolution (HR) image from a low-resolution input image. Due to the severely under-determined nature of this problem, an effective image prior is necessary to make the problem solvable, and to improve the quality of generated images. In this paper, a novel image superresolution algorithm is proposed based on gradient profile sharpness (GPS). GPS is an edge sharpness metric, which is extracted from two gradient description models, i.e., a triangle model and a Gaussian mixture model for the description of different kinds of gradient profiles. Then, the transformation relationship of GPSs in different image resolutions is studied statistically, and the parameter of the relationship is estimated automatically. Based on the estimated GPS transformation relationship, two gradient profile transformation models are proposed for two profile description models, which can keep profile shape and profile gradient magnitude sum consistent during profile transformation. Finally, the target gradient field of HR image is generated from the transformed gradient profiles, which is added as the image prior in HR image reconstruction model. Extensive experiments are conducted to evaluate the proposed algorithm in subjective visual effect, objective quality, and computation time. The experimental results demonstrate that the proposed approach can generate superior HR images with better visual quality, lower reconstruction error, and acceptable computation efficiency as compared with state-of-the-art works.
Design and development of continuum structure for robotic flower

In this paper describes the design, modeling and development of a robotic flower based on continuum structure. It is the new concept of biomimetics, and its appearance likes a natural flower. The design is based on a novel “tendon and spring” mechanisms. The robotic flower is steered by tendons combining structure of spring. Its development is novel with respect to previous robotic flower's designs in that flexibility, and extension, in addition to bending, are actively controlled in each direction of the robot and cheap. This requires a proposed kinematic model, and poses challenges for real-time control of the robot. In the paper, the design and its development are presented, along with a real-time control issues and experimental results. Robotic flower has three main parts are several leaves, a stem and a flower which can move respectively together or seperately. The mechanical structure is designed specifically to help the flowers have softness and flexible movement. The spring and tendon mechanism are combined to build a robotic flower. Beside like as natural flower, the robot can move toward light, sway to the music or recognize the strange people into the house.
Broadband single-feed microstrip antenna in a fabry-perot resonator

We designed a single-feed microstrip antenna in a Fabry-Perot resonator cavity used for Ku-band (12-18 GHz) applications. A cavity was formed by a ground plane and a frequency selective surface made of a circular hole array and was excited by a single-feed microstrip patch located inside the cavity. The antenna with low-profile and reduced thickness produced a high gain (~19 dBi) and a broad bandwidth (~7%). The optimized antenna was fabricated, and the measured results were close to the simulated ones.
Image Superresolution Using Support Vector Regression

A thorough investigation of the application of support vector regression (SVR) to the superresolution problem is conducted through various frameworks. Prior to the study, the SVR problem is enhanced by finding the optimal kernel. This is done by formulating the kernel learning problem in SVR form as a convex optimization problem, specifically a semi-definite programming (SDP) problem. An additional constraint is added to reduce the SDP to a quadratically constrained quadratic programming (QCQP) problem. After this optimization, investigation of the relevancy of SVR to superresolution proceeds with the possibility of using a single and general support vector regression for all image content, and the results are impressive for small training sets. This idea is improved upon by observing structural properties in the discrete cosine transform (DCT) domain to aid in learning the regression. Further improvement involves a combination of classification and SVR-based techniques, extending works in resolution synthesis. This method, termed kernel resolution synthesis, uses specific regressors for isolated image content to describe the domain through a partitioned look of the vector space, thereby yielding good results
A Multistage Motion Vector Processing Method for Motion-Compensated Frame Interpolation

In this paper, a novel, low-complexity motion vector processing algorithm at the decoder is proposed for motion-compensated frame interpolation or frame rate up-conversion. We address the problems of having broken edges and deformed structures in an interpolated frame by hierarchically refining motion vectors on different block sizes. Our method explicitly considers the reliability of each received motion vector and has the capability of preserving the structure information. This is achieved by analyzing the distribution of residual energies and effectively merging blocks that have unreliable motion vectors. The motion vector reliability information is also used as a prior knowledge in motion vector refinement using a constrained vector median filter to avoid choosing identical unreliable one. We also propose using chrominance information in our method. Experimental results show that the proposed scheme has better visual quality and is also robust, even in video sequences with complex scenes and fast motion.
Modeling, Prediction, and Reduction of 3D Crosstalk in Circular Polarized Stereoscopic LCDs

Crosstalk, which is the incomplete separation between the left and right views in 3D displays, induces ghosting and causes difficulty of the eyes to fuse the stereo image for depth perception. Circularly polarized (CP) liquid crystal display (LCD) is one of the main-stream consumer 3D displays with the prospering of 3D movies and gamings. The polarizing system including the patterned retarder is one of the major causes of crosstalk in CP LCD. The contributions of this paper are the modeling of the polarizing system of CP LCD, and a crosstalk reduction method that efficiently cancels crosstalk and preserves image contrast. For the modeling, the practical orientation of the polarized glasses (PG) is considered. In addition, this paper calculates the rotation of the light-propagation coordinate for the Stokes vector as light propagates from LCD to PG, and this calculation is missing in the previous works when applying Mueller calculus. The proposed crosstalk reduction method is formulated as a linear programming problem, which can be easily solved. In addition, we propose excluding the highly textured areas in the input images to further preserve image contrast in crosstalk reduction.
ECG compression using discrete symmetric wavelet transform

This paper proposes a new ECG signal compression algorithm using a discrete symmetric wavelet transform. This proposed compression scheme may find applications in digital Holter recording, in ECG signal archiving and in ECG data transmission through communication channels. Using the new method, a compression ratio of 8 to 1 can be achieved with PRD=3.9%, in contrast to the AZTEC compression ratio of 6.8 to 1 with PRD=10.0% and the fan algorithm compression ratio of 7;4 to 1 with PRD=8.1%.
Entropy of General Gaussian Distributions and MIMO Channel Capacity Maximizing Precoder and Decoder

Exploiting channel state information at the transmitter and receiver to design an optimal linear precoder and decoder for a multiple-input multiple-output (MIMO) communication system is an active research area. The design is often based on the information rate criterion, that is to design the precoder and decoder such that the system capacity is maximized, subject to the average transmit power constraint. Although such an optimization problem has been considered intensively and there have been numerous proposals so far, they are not rigorously correct. We propose a mathematically rigorous framework for solving this optimization problem. Our proposed solution is applicable to both MIMO flat fading and frequency selective fading channels. Simulations verify the theoretical analysis.
Theory and design of shift-invariant filter banks and wavelets

A drawback of the critical-sampling multirate system is its shift-variant property at the subband output. This prevents wavelets from many applications where shift-invariance is required. For a given set of filter coefficients and cost function, all of the existing methods solve the problem by finding the path in the decomposition tree that minimizes shift-variance with respect to a given cost function. This procedure is signal dependent and is inefficient, especially for long data sets and images, since the subband decomposition has to be performed for all shifts of input signal during the processing time. In this paper, we establish a framework for a shift-invariant filter bank by connecting the relation between the polyphase representation and shift-invariant property of filter banks. Theory, analysis, and design are presented, and comparison to the existing systems is discussed. Design examples and simulations on image coding are presented.
Design of approximated DCT with large size and its application to image matching

We present the design of approximated discrete cosine transform (DCT) with large size and its performance. The approximated DCT is designed using Wang's matrix factorization algorithms with fixed-point parameters and the size greater than 2k, k > 4 is focused. So far, the specific parameters and performance of approximated DCT with large size have not been presented. In addition, we apply the sign of approximated DCT to image matching. Compared to floating-point DCT, the superior performance of the sign of the approximated DCT is demonstrated through experimental results.
Fast single image fog removal using the adaptive Wiener filter

We present in this paper a fast single image defogging method that uses a novel approach to refining the estimate of amount of fog in an image with the Locally Adaptive Wiener Filter. We provide a solution for estimating noise parameters for the filter when the observation and noise are correlated by decorrelating with a naively estimated defogged image. We demonstrate our method is 50 to 100 times faster than existing fast single image defogging methods and that our proposed method subjectively performs as well as the Spectral Matting smoothed Dark Channel Prior method.
Minimum Mean-Squared Error Reconstruction for Generalized Undersampling of Cyclostationary Processes

The generalized sampling problem is considered using a filter bank model with a stochastic process framework. A signal reconstruction solution minimizing the time-averaged mean-squared error is found using a filter bank optimization technique for cyclostationary signals. The use of a stochastic model approach to find a minimized error solution rather than a perfect reconstruction solution allows consideration of sampling problems that deterministic approaches cannot solve. For instance, a particular sampling density is not required, allowing reconstruction optimization in cases of undersampling. An extension is also presented for optimal reconstruction in the presence of additive noise and interference. The result is a generalized sampling model which can be used for an extensive variety of scenarios, combining aspects of undersampling, multiple-input multiple-output (MIMO) sampling, and periodic nonuniform sampling
Eigenfilters for the design of special transfer functions with applications in multirate signal processing

Based on the multistage approach, a design procedure is presented for finding a spectral factor of an mth-band filter and for designing multistage decimation filters. The proposed design method finds spectral factors of mth-band FIR (finite-impulse response) filters without direct computation, and yields filters with much higher attenuation than would be possible by conventional methods. Such mth-band filters are used in filter-bank designs, including perfect-reconstruction systems.<<ETX>>
The low-cost single-stage grid connected photovoltaic system with a modified MPPT method

Single-stage topology and the maximum power point tracking (MPPT) algorithm have advantages such as simple configuration and high efficiency in grid-connected photovoltaic (PV) systems. However, in conventional systems, current and voltage sensors of PV system are normally used for MPPT. This paper presents a low-cost single-stage grid- connected PV system without PV current sensor with a modified MPPT method. This method is not derived from complex state equations and is not dependent on any circuit parameters. It simply calculates the output power of the inverter to replace the input power of the PV systems in the MPPT algorithm. The new algorithm is simulated by using Matlab/Simulink software and implemented in the experimental prototype. With the one-stage configuration and PV current sensorless method, the prototype is suitable for lowcost implementation in the practice.
Fast LCD motion deblurring by decimation and optimization

The LCD deblurring problem is considered as a simple bounded quadratic programming problem and is solved using conjugate gradient with early stopping criteria to avoid excessive search. A decimation and interlace interpolation method is introduced to reduce the computing time. Solutions are competitive to those the generated by conventional Lucy Richardson algorithm, but using much shorter amount of time. The method can be extended to higher decimation factors. Visual subjective tests are conducted to justify our proposed method.
Efficiency enhancement of bi-layer solar cells utilizing graded bandgap active layer

The graded bandgap light absorption layers were inserted as an active layer in the bi-layer solar cell of ITO/PEDOT:PSS/CuPc/C60/BCP/Al structure. The effect of variation of relative thicknesses of the graded bandgap absorption layers were elucidated and optimized for the improvement in photovoltaic efficiency. The organic bi-layer solar cells were fabricated by using thermally evaporated graded bandgap layers, while maintaining the total active layer thickness constant. It was found that the thickness of lower bandgap layer beneath the higher bandgap layer predominantly controls the overall efficiency of the bi-layer cell, converting most of the light into the photocurrent. It was also found that the deposition rate control is critical in obtaining the enhancement of device efficiency, in that slower deposition rate provides better cell performance. The solar cell efficiency was measured from a solar simulator at AM 1.5 100 mW/cm2.
Spatioangular Prefiltering for Multiview 3D Displays

In this paper, we analyze the reproduction of light fields on multiview 3D displays. A three-way interaction between the input light field signal (which is often aliased), the joint spatioangular sampling grids of multiview 3D displays, and the interview light leakage in modern multiview 3D displays is characterized in the joint spatioangular frequency domain. Reconstruction of light fields by all physical 3D displays is prone to light leakage, which means that the reconstruction low-pass filter implemented by the display is too broad in the angular domain. As a result, 3D displays excessively attenuate angular frequencies. Our analysis shows that this reduces sharpness of the images shown in the 3D displays. In this paper, stereoscopic image recovery is recast as a problem of joint spatioangular signal reconstruction. The combination of the 3D display point spread function and human visual system provides the narrow-band low-pass filter which removes spectral replicas in the reconstructed light field on the multiview display. The nonideality of this filter is corrected with the proposed prefiltering. The proposed light field reconstruction method performs light field antialiasing as well as angular sharpening to compensate for the nonideal response of the 3D display. The union of cosets approach which has been used earlier by others is employed here to model the nonrectangular spatioangular sampling grids on a multiview display in a generic fashion. We confirm the effectiveness of our approach in simulation and in physical hardware, and demonstrate improvement over existing techniques.
Hardware feasibility analysis for motion segmentation initialization

We analyze and evaluate different initialization methods for motion layers segmentation, a powerful mid-level vision tool. We estimate 6-D affine motion models from the optical flow corresponding to different over-segmentations. Over-segmentations can be either uniform rectangular blocks; or adaptive sized rectangular blocks; or super-pixels; or based on any other clustering methods. We present performance analysis of motion segmentation initialization algorithms on video sequences and discuss the relative pros and cons of these methods in terms of hardware implementation issues.