nils-herrmann/clean_scirepeval huggingface dataset:
Robust Absorption in a Four-Layer Dielectric-Metal Structure

This letter predicts that robust absorption will appear in a four-layer dielectric-metal structure, and our experimental results verify this prediction well. The mechanisms are as follows: 1) The four layers form a cavity, and zero phase shift at the interface between the first metallic layer and the second dielectric layer is designed to make the backward light form a destructive interference and minimize the reflection. 2) The slow-light effect near the cutoff frequency in this structure increases the absorptive length many times. 3) It also can be explained as an asymmetric resonator, which satisfies the critical coupling condition. Many applications can be developed from this work, such as ensuring laser welding high quality for infrared transparent optoelectronic components.
SSIM-Inspired Perceptual Video Coding for HEVC

Recent advances in video capturing and display technologies, along with the exponentially increasing demand of video services, challenge the video coding research community to design new algorithms able to significantly improve the compression performance of the current H.264/AVC standard. This target is currently gaining evidence with the standardization activities in the High Efficiency Video Coding (HEVC) project. The distortion models used in HEVC are mean squared error (MSE) and sum of absolute difference (SAD). However, they are widely criticized for not correlating well with perceptual image quality. The structural similarity (SSIM) index has been found to be a good indicator of perceived image quality. Meanwhile, it is computationally simple compared with other state-of-the-art perceptual quality measures and has a number of desirable mathematical properties for optimization tasks. We propose a perceptual video coding method to improve upon the current HEVC based on an SSIM-inspired divisive normalization scheme as an attempt to transform the DCT domain frame prediction residuals to a perceptually uniform space before encoding. Based on the residual divisive normalization process, we define a distortion model for mode selection and show that such a divisive normalization strategy largely simplifies the subsequent perceptual rate-distortion optimization procedure. We further adjust the divisive normalization factors based on local content of the video frame. Experiments show that the proposed scheme can achieve significant gain in terms of rate-SSIM performance when compared with HEVC.
Analytical study of FFH systems with square-law diversity combining in the presence of multitone interference

An analytical study of the performance of fast frequency-hopped (FFH), M-ary orthogonal frequency-shift keyed noncoherent modulation with linear combining of square-law envelopes in the presence of multitone interference is presented. The multiple equal-power interference tones are assumed to correspond to some of the possible FFH/M-ary orthogonal signaling tones. It is also assumed that the channel fading characteristics of the signal and interference tones are independent. We evaluate the effect of the channel fading on the system's performance as a function of various parameters, such as the number of hops per symbol, the signal power to multitone interference power ratio, and the number of interference tones. Our numerical results indicate that by use of square-law time diversity combining, a large number of hops per symbol make the bit-error probability of the system more sensitive to the fading of multitone interference. Finally, the analysis has been proven valid by simulation.
An Efficient and Robust Method for Automatically Identifying the Left Ventricular Boundary in Cine Magnetic Resonance Images

Efficient and robust identification of the left ventricular borders remains a challenging problem in cardiology. In this paper, we proposed an automatic method to segment the left ventricles and then identify their borders robustly. The proposed method is named as “ABDC” because it utilizes the strengths of four techniques: Automatic threshold selection; Boundary extraction, Deformation flow tracking, and Convex shape modeling. We compared the proposed method with the PDE optical flow method on 1660 images which are obtained from ten complete short-axis cine MRI datasets (five normal subjects and five patients). As it turned out, the proposed method is more efficient and robust than the benchmark in segmenting LV borders.
Spectrum reuse in microcellular and distributed antenna systems

The microcellular system and distributed antenna system (DAS) are two promising systems to provide high data rate for future wireless communications, especially for the cell edge of the macrocell, because both systems can reduce the radio transmission distance. The cell edge spectrum efficiency is theoretically compared between the two systems in a network topology with seven macrocells, each of which has seven hexagonal sectors. Numerical results show that, when the spatial diversity and spectrum reuse are adopted in the DAS, the cell edge spectrum efficiencies per sector in the DAS is larger than these in the microcellular system.
Blind measurement of blocking artifacts in images

The objective measurement of blocking artifacts plays an important role in the design, optimization, and assessment of image and video coding systems. We propose a new approach that can blindly measure blocking artifacts in images without reference to the originals. The key idea is to model the blocky image as a non-blocky image interfered with a pure blocky signal. The task of the blocking effect measurement algorithm is then to detect and evaluate the power of the blocky signal. The proposed approach has the flexibility to integrate human visual system features such as the luminance and the texture masking effects.
Analysis and Design of Channel Estimation in Multicell Multiuser MIMO OFDM Systems

This paper investigates the uplink transmission in multicell multiuser multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) systems. The system model considers imperfect channel estimation, pilot contamination (PC), and multicarrier and multipath channels. Analytical expressions are first presented on the mean square error (MSE) of two classical channel estimation algorithms [i.e., least squares (LS) and minimum mean square error (MMSE)] in the presence of PC. Then, a simple H-infinity (H-inf) channel estimation approach is proposed to have good suppression to PC. This approach exploits the space-alternating generalized expectation-maximization (SAGE) iterative process to decompose the multicell multiuser MIMO (MU-MIMO) problem into a series of single-cell single-user single-input single-output (SISO) problems, which reduces the complexity significantly. According to the analytic results given herein, increasing the number of pilot subcarriers cannot mitigate PC, and a clue for suppressing PC is obtained. It is shown from the results that the H-inf has better suppression capability to PC than classical estimation algorithms. Its performance is close to that of the optimal MMSE as the length of channel impulse response (CIR) is increased. By using the SAGE process, the performance of the H-inf does not degrade when the number of antennas is large at the base station (BS).
Reduced-Reference Image Quality Assessment Using Divisive Normalization-Based Image Representation

Reduced-reference image quality assessment (RRIQA) methods estimate image quality degradations with partial information about the ldquoperfect-qualityrdquo reference image. In this paper, we propose an RRIQA algorithm based on a divisive normalization image representation. Divisive normalization has been recognized as a successful approach to model the perceptual sensitivity of biological vision. It also provides a useful image representation that significantly improves statistical independence for natural images. By using a Gaussian scale mixture statistical model of image wavelet coefficients, we compute a divisive normalization transformation (DNT) for images and evaluate the quality of a distorted image by comparing a set of reduced-reference statistical features extracted from DNT-domain representations of the reference and distorted images, respectively. This leads to a generic or general-purpose RRIQA method, in which no assumption is made about the types of distortions occurring in the image being evaluated. The proposed algorithm is cross-validated using two publicly-accessible subject-rated image databases (the UT-Austin LIVE database and the Cornell-VCL A57 database) and demonstrates good performance across a wide range of image distortions.
Performance of multicarrier DS/SFH-CDMA systems

In this paper, multicarrier direct-sequence/slow-frequency-hopping (DS/SFH) CDMA systems are proposed, in which multiple carriers are modulated by the same DS waveform and hopped in frequency according to a hopping pattern. It is shown that the multicarrier DS/SFH systems are superior to the multicarrier DS systems in reducing multiple access interference while preserving the good capability of narrowband interference suppression, when the system parameters are selected properly.
Study and AISC design of a high efficiency OLED scan controller

As a novel display material, OLED attracts more and more attention in recent years. This paper researches on the OLED scanning control circuit, and puts forward a novel adjustable grayscale scan method which adopts random weight algorithm after studying different scan schemes. Considering the efficiency of scan buffer unit, a dual radix interleaving clock architecture is proposed in the paper, and the ASIC design of scanning control chip is also carried out. The experimented result convinces that the efficiency of the novel scan circuit is enhanced approximately 50%. Meanwhile, the innovational gray control method for FPD with independent intellectual property rights is also obtained.
Approximate interference of a microcellular spread spectrum system [comment]

An approximate technique for determining the adjacent cell interference of a microcellular code division multiple access (CDMA) system is described in the original paper [see ibid., vol. 31,  1995]. An illustration of the hexagonal cellular model is given in that paper. The argument for the proposed technique is the following: since the variance of adjacent cell interference depends on the position of the mobile user in an adjacent cell, it is difficult to evaluate the exact value of variance for this hexagonal cellular model. To avoid dependence on position, the calculated variance of adjacent cell interference is averaged over the area of the cell where the mobile user is located. Furthermore, the hexagonal cell is approximated with a circular cell of equal area criterion. However, the approximation of a hexagonal cell by a circular cell with equal area is inaccurate.
3D-SSIM for video quality assessment

Effective and efficient objective video quality assessment (VQA) methods are highly desirable in modern visual communication systems for performance evaluation, quality control and resource allocation purposes. Simple VQA algorithms may be developed by direct extensions of still image quality assessment (IQA) approaches on a frame-by-frame basis. Advanced VQA methods take into account the temporal correlation and motion information contained in video signals but often lead to significantly increased computational complexity. Here we use a different approach to examine a video signal by considering it as a three-dimensional (3D) volume image. Specifically, we propose a 3D structural similarity (3D-SSIM) approach, which first creates a 3D quality map by applying SSIM evaluations within local 3D blocks, and then use local information content and local distortion based weighting methods to pool the quality map into a single quality measure. The resulting 3D-SSIM algorithm is computationally efficient and demonstrates highly competitive performance in comparison with state-of-the-art VQA algorithms when tested using four publicly available video quality databases.
Pore-forming agent's influence on properties of Al-Fe sound-absorbing materials synthesized by self-propagation high-temperature synthesizing (SHS)

In this article, we will discuss the influence of NaCl and anhydrous K2CO3 Pore-forming agent on the porosity properties of Al-Fe absorption materials synthesized by SHS; The research results show that: (1)Under the conditions of the same frequency, with the NaCl and anhydrous K2CO3 volume content increased, the specimen porosity gradually increases, and the absorption coefficient increased linearly; (2) under the same experiment conditions, using NaCl as Pore-forming agent for Al-Fe absorption materials synthesized by SHS, its sound absorption properties is significantly higher than that using anhydrous K2CO3 as the Pore-forming agent.
Combing structured light measurement technology with binocular stereo vision

3D measurement technology is one of the important research fields in computer vision. 3D measurement based on binocular stereo vision is a typical measurement technique. In this paper, the structured light technology is combined with binocular stereo technology. The structured light can increase the feature of object's surface, so we can reconstruct the surface of object more robustly. In this paper, we establish the 3D imaging system, obtain the point of 3D coordinates on the imaging plane, and then extract the center of the stripe image. Based on the stripe center, we propose a new method of matching. At last, we reconstruct the 3D surface of the object by calculating the interception points of two rays with analytical solutions. The experimental results show that the method is feasible and efficient.
Perceptual quality assessment of high frame rate video

High frame rate video has been a hot topic in the past few years driven by a strong need in the entertainment and gaming industry. Nevertheless, progress on perceptual quality assessment of high frame rate video remains limited, making it difficult to evaluate the exact perceptual gain by switching from low to high frame rates. In this work, we first conduct a subjective quality assessment experiment on a database that contains videos compressed at different frame rates, quantization levels and spatial resolutions. We then carry out a series of analysis on the subjective data to investigate the impact of frame rate on perceived video quality and its interplay with quantization level, spatial resolution, spatial complexity, and motion complexity. We observe that perceived video quality generally increases with frame rate, but the gain saturates at high rates. Such gain also depends on the interactions between quantization level, spatial resolution, and spatial and motion complexities.
Downlink TCP Performance Under Cross Layer Rate and Power Allocation in Infrastructure TH-PPM UWB Networks

Ultra wideband (UWB) systems are currently an important wireless infrastructure for efficient short- range communications. To improve the system efficiency while guaranteeing the radio link level quality of services, transmission rate and power of the mobile nodes can be dynamically adjusted by executing an optimization algorithm at the access points (APs). In this paper, we present a cross layer rate and power allocation algorithm based on the multilayer model of time hopping (TH) pulse position modulation (PPM) UWB multimedia networks. We consider the performance of the TCP protocol under the proposed cross layer allocation scheme in various realistic UWB based infrastructure networking scenarios.
A Novel Code Assignment Scheme for Broadband OFCDM Systems

To provide high speed mobile services, multi-code transmission is employed in the orthogonal frequency and code division multiplexing (OFCDM) system. However, the code channel orthogonality is distorted by the broadband wireless channel, and multi-code interference (MCI) is caused. The amount of the MCI is dependent on which codes to be used. This paper investigates the code assignment in the multi-code OFCDM system, aiming to mitigate the MCI at the receiver. In terms of the code distance defined in this paper, a novel code assignment scheme is proposed. It has been shown that the system performance can be improved significantly by the proposed scheme under various channel conditions, especially when a low to medium system load is assumed
A novel receiver for FHMA systems

A novel FH/MFSK receiver with additional partial correlators is proposed by means of side information for asynchronous frequency-hopping multiple-access (FHMA) systems in the presence of Rayleigh fading. Performance analysis is carried out and compared for both the novel and conventional receivers. One hop per symbol and Reed-Solomon (RS) coding are used in the FHMA systems. It is shown that the novel receiver performs much better than the conventional receiver for a wide range of signal to noise ratio. The capacity of the FHMA system with novel receivers is almost as twice as that of the system with conventional receivers.
DS-SSMA star network over indoor radio multipath Rician fading channels

The authors investigate the bit error rate (BER) performance of a direct-sequence spread-spectrum multiple-access (DS-SSMA) star network operating over a multipath Rician fading channel (which models indoor radio propagation in factories). They consider both phase-shift-keying modulation with coherent demodulation and differential phase-shift-keying modulation with noncoherent demodulation. Predetection multipath diversity (maximal ratio combining for coherent reception and equal gain combining for noncoherent reception) and simple channel coding are used for improving the BER performance. Numerical results for the BER of both coherent and noncoherent systems show that predetection multipath diversity plus coding is a very efficient technique for improving the BER performance of systems over multipath Rician fading channels and that, for the indoor radio channels in factories, the noncoherent system is preferable.<<ETX>>
Broadband VSF-OFCDM systems with hybrid MCI cancellation and MMSE detection

An analytical study is presented on the performance of the variable spreading factor orthogonal frequency and code division multiplexing (VSF-OFCDM) system with hybrid multi-code interference (MCI) cancellation and minimum mean square error (MMSE) detection. The weights of MMSE are derived, and should be updated stage by stage of MCI cancellation. Various values of time and frequency domain spreading factors are dealt with in a QPSK-modulated VSF-OFCDM system. It is shown that the hybrid detection scheme performs much better than the conventional MMSE. For the hybrid detection, a larger value of the frequency domain spreading factor is expected.
A Study On Temperature Distribution of arc Cross Section of Low-Voltage Apparatus

In this paper, a set of hardware instruments used to collect arc radiant intensity in three directions were designed by using single area CCD based on high temperature characteristic of low-voltage apparatus switch arc, and the principle of computer tomogram and corresponding image processing software was also developed. We took pictures for the projection of breaking arc radiation of the low-voltage AC contactor in inductance circuits, and rebuilt its temperature distribution on different sections when burning.
Fabrication and Characterization of HAp/Al2O3 Composite Coating on Titanium Substrate

HAp/Al2O3 composite coating was fabricated onto micro-arc oxidized titanium substrate using a combination of electrophoretic deposition and reaction bonding process. SEM, EDS and XRD were employed to characterize the titanium substrate and as-prepared coatings. The interfacial bonding strength of the sintered composite coating was tested by shear strength testing experiment. Results show that the green form composite coating can be easily sintered with no cracks and decomposition at 850degC, the bonding strength to the substrate is significantly improved compared with the single HAp coating.
Waterloo Exploration Database: New Challenges for Image Quality Assessment Models.

The great content diversity of real-world digital images poses a grand challenge to image quality assessment (IQA) models, which are traditionally designed and validated on a handful of commonly used IQA databases with very limited content variation. To test the generalization capability and to facilitate the wide usage of IQA techniques in real-world applications, we establish a large-scale database named the Waterloo Exploration Database, which in its current state contains 4744 pristine natural images and 94 880 distorted images created from them. Instead of collecting the mean opinion score for each image via subjective testing, which is extremely difficult if not impossible, we present three alternative test criteria to evaluate the performance of IQA models, namely, the pristine/distorted image discriminability test, the listwise ranking consistency test, and the pairwise preference consistency test (P-test). We compare 20 well-known IQA models using the proposed criteria, which not only provide a stronger test in a more challenging testing environment for existing models, but also demonstrate the additional benefits of using the proposed database. For example, in the P-test, even for the best performing no-reference IQA model, more than 6 million failure cases against the model are "discovered" automatically out of over 1 billion test pairs. Furthermore, we discuss how the new database may be exploited using innovative approaches in the future, to reveal the weaknesses of existing IQA models, to provide insights on how to improve the models, and to shed light on how the next-generation IQA models may be developed. The database and codes are made publicly available at: https://ece.uwaterloo.ca/~k29ma/exploration/.
Cooperative Performance and Diversity Gain of Wireless Relay Networks

In this paper, the error rate performance and diversity gain of amplify-and-forward (AF) wireless relay networks are studied. The distributed space-time block code (DSTBC) in a synchronous relay network with multiple relay nodes is considered. The distributed linear dispersion code is used at the relays. The symbol (or codeword) error rate is studied in terms of upper and lower bounds through rigorous derivations, and the diversity gain of the DSTBC is derived, for any number of relay nodes. As a corollary, a necessary and sufficient condition is obtained for achieving full cooperative diversity. Arbitrary coding matrices at the relays, path loss and general linear power allocation are considered. Finally, the orthogonal frequency division multiplexing (OFDM)-based space-time transmission scheme in asynchronous cooperative networks is also discussed.
Adaptive LMS Filters for Cellular CDMA Overlay Situations

This paper extends and complements previous research we have performed on the performance of nonadaptive narrowband suppression filters when used in cellular code-division multiple-access (CDMA) overlay situations. An adaptive least mean square (LMS) filter is applied to a cellular CDMA overlay in order to reject narrowband interference. An accurate expression for the steady-state tap-weight covariance matrix is derived for the real LMS algorithm for arbitrary statistics of the overlaid interference. Numerical results illustrate that when the ratio of the narrowband interference bandwidth to the spread spectrum bandwidth is small, the LMS filter is very effective in rejecting the narrowband interference. Furthermore, it is seen that the performance of the LMS filter in a CDMA overlay environment is not significantly worse than the performance of an ideal Wiener filter, assuming the LMS filter has had sufficient time to converge.