nils-herrmann/clean_scirepeval huggingface dataset:
A two stage parallel encoder scheme for real time video encoder

With the development of hardware technologies, multi-core processor becomes more and more popular. At the same time, the performance of video encoding technologies is greatly improved at the cost of complexity. How to exploit the computing capacity of the multi-core processors efficiently to meet the demand of video encoding technology is a challenging task. Traditional work usually split the frame into slices to enable parallel encoding. But the coding efficiency will lose especially when there are more slices. In this paper, first we propose a two stage real time encoding scheme without splitting the frame into slices. Secondly, some modules in the hybrid video coding scheme, such as interpolation and loop filter, are split into independent modules that can be processed in parallel. A simple and effective task scheduling strategy is also proposed to fully exploit the CPU capacity. Finally, fast algorithms suitable for this architecture are developed. Experimental results show that we can encode the 720p sequence at about 50 fps with little loss in the rate distortion performance.
Power quality improvement utilizing photovoltaic generation connected to a weak grid

Microgrid research and development in the past decades have been one of the most popular topics. Similarly, the photovoltaic generation has been surging among renewable generation in the past few years, thanks to the availability, affordability, technology maturity of the PV panels and the PV inverter in the general market. Unfortunately, quite often, the PV installations are connected to weak grids and may have been considered as the culprit of poor power quality affecting other loads in particular sensitive loads connected to the same point of common coupling (PCC).  The main objective of this work is to develop a control method for the PV inverter so that the power quality at the PCC will be improved under various disturbances. The method is to control the reactive current based on utilizing the grid current to counteract the negative impact of the disturbances. The proposed control method is verified in PSIM platform. Promising results have been obtained.
A robust watermarking method based on wavelet and Zernike transform

As watermarking is increasingly applied for a variety of applications, various properties of watermarks, such as how they respond to common signal transformations or deliberate attacks, have become important concerns. In this paper, we propose a new approach to embed a watermark that is to modify the block average in wavelet domain. If the watermarked image has been attacked by geometric ways, we can figure it out by Zernike transform and then retrieve it. Experiments prove that the method is not only robust to geometric attacks, but also to JPEG and Checkmark attacks.
An adaptive dandelion model for reconstructing spherical terrain-like visual hull surfaces

In this paper we present an adaptive dandelion model for reconstructing spherical terrain-like visual hull (VH) surfaces. The dandelion model represents a solid by a pencil of organized line segments emitted from a common point. The directions and the topology of the line segments are derived from the triangle facets of a geodesic sphere, which are recursively subdivided until the desired precision is achieved. The initial lines are cut by silhouettes in 2D and then lifted back to 3D to determine the ending points of the line segments defining sampling points on the spherical terrain-like VH surface. A mesh model can be easily constructed from the dandelion model. Our algorithm has the advantages of controllable precision, adaptive resolution, simplicity and speediness. We validate our algorithm by theories and experiments.
Bagging Based Efficient Kernel Fisher Discriminant Analysis for Face Recognition

Kernel Fisher discriminant analysis (KFDA) has achieved great success in pattern recognition recently. However, the training process of KFDA is too time consuming (even intractable) for a large training set, because, for a training set with n examples, both its between-class and within-class scatter matrices are of n times n and the time complexity of the KFDA training process is of O(n3). Aiming at this problem, this paper employs bagging technique to decrease the time-space cost of KFDA training process. In addition, this paper is more than just a simple application of bagging. We have made an important adaptation which can further guarantee the performance of KFDA. Our experimental results demonstrate that the proposed method can not only greatly reduce the cost of time of the training process, but also achieve higher recognition accuracy than traditional KFDA and the simple application of bagging
Continuous-time equivalents of welch bound equality sequences

In this paper, the optimal signaling problem for multiple-access communications over Gaussian overloaded channels is considered with equal-power users having linear minimum mean-squared error (LMMSE) receivers. Unlike previous similar work on the sequence design for code-division multiple-access (CDMA) communications where discrete-time or vector channel models are predominantly employed, the overloaded channel is modeled as a strictly band-limited, continuous-time multiple-access channel corrupted by an additive white Gaussian noise. After being posed as a multi-input/single-output (MISO) joint transmitter and receiver optimization problem with the total mean-squared error as the objective functional, the variational problem is solved by using a frequency-domain approach. It is shown that the matched filters are the optimal receivers and that there exist continuous-time equivalents of Welch bound equality (CTE-WBE) sequences as the optimal transmit waveforms. The user capacity of the band-limited channel in terms of the admissibility of users into the system is also characterized by a necessary and sufficient condition on the channel load, the received signal-to-noise ratio, and the maximum signal-to-interference ratio.
Parameter-dependent robust stability for nonlinear distributed delay stochastic systems with polytopic-type uncertainties

The robust stability problem for nonlinear distributed delay stochastic systems with polytopic-type uncertainties is discussed. Based on parameter-dependent Lyapunov-krasovs-kii functional and free-weighting matrix method, a delay-dependent and parameter-dependent stability condition is presented in terms of linear matrix inequalities. The result in this paper improves the existing stability criteria and has less conservativeness. The simulation example shows that the result is effective.
Research and development of self-energy SF6 circuit breaker on the breaking capacity

By improving of the dielectric performance between the breakers, medium condition and arc extinguishing ability, the breaking capacity of circuit breaker is increased. The main architecture of the 252kV circuit breaker is determined in which double chamber of interrupter construction + dual-direction moving of contacts mode are introduced. The key structure design parameter have been optimized combined with the design experiences of the finalized product: The volume of thermal expand chamber and puffer chamber as well as the cooperation between them are determined which ensures the breaking of the high current. Electric field analysis software is used to calculate, analyze and optimize the electric field strength of the circuit breaker contacts in some sensitive positions. Improving airflow channel for the decrease of the gas density is to be restrained and the hot gas exhaust efficiency is to be increased. As a result, the medium condition is improved. All the test verification has achieved for the researched and developed circuit breaker, and the product have been on stream. In the meantime, it provides the new technical foundation for the various following switchgears.
Improved ant colony optimization algorithm and its application for path planning of mobile robot in 3-D space

An improved ant colony algorithm, differential evolution chaos ant colony optimization (DEACO) algorithm, was proposed to plan an optimal collision-free path for mobile robot in 3-D environment. It utilized differential evolution algorithm to update pheromone and chaos disturbance factor was added when pheromone updates for possible stagnation phenomenon. So it enhances escaping capability of algorithm, avoids path-deadlock situations as well as improves the efficiency of planning optimal path. The simulation results indicated that the optimal path on which the robot moves can reach safely and can be rapidly obtained under 3-D space environment, the effect being very satisfactory.
Fast and Efficient Transcoding Based on Low-Complexity Background Modeling and Adaptive Block Classification

It is in urgent need to develop fast and efficient transcoding methods so as to remarkably save the storage of surveillance videos and synchronously transmit conference videos over different bandwidths. Towards this end, the special characteristics of these videos, e.g., the relatively static background, should be utilized for transcoding. Therefore, we propose a fast and efficient transcoding method (FET) based on background modeling and block classification in this paper. To improve the transcoding efficiency, FET adds the background picture, which is modeled from the originally decoded frames in low complexity, into stream in the form of an intra-coded G-picture. And then, FET utilizes the reconstructed G-picture as the long-term reference frame to transcode the following frames. This is mainly because our theoretical analyses show that G-picture can significantly improve the transcoding performance. To reduce the complexity, FET utilizes an adaptive threshold updating model for block classification and then adopts different transcoding strategies for different categories. This is due to the following statistics: after dividing blocks into categories of foreground, background and hybrid ones, different block categories have different distributions of prediction modes, motion vectors and reference frames. Extensive experiments on transcoding high-bit-rate H.264/AVC streams to low-bit-rate ones are carried out to evaluate our FET. Over the traditional full-decoding-and-full-encoding methods, FET can save more than 35% of the transcoding bit-rate with a speed-up ratio of larger than 10 on the surveillance videos. On the conference videos which should be transcoded more timely, FET achieves more than 20 times speed-up ratio with 0.2 dB gain.
An assessment of the impact of stochastic day-ahead SCUC on economic and reliability metrics at multiple timescales

This paper incorporates the stochastic day-ahead security-constrained unit commitment (DASCUC) within a multi-timescale, multi-scheduling application with commitment, dispatch, and automatic generation control. The stochastic DASCUC is solved using a progressive hedging algorithm with constrained ordinal optimization to accelerate the individual scenario solution. Sensitivity studies are performed in the RTS-96 system, and the results show how this new scheduling application would impact costs and reliability with a closer representation of timescales of system operations in practice.
Hallucinating facial images and features

In facial image analysis, image resolution is an important factor which has great influence on the performance of face recognition systems. As for low-resolution face recognition problem, traditional methods usually carry out super-resolution firstly before passing the super-resolved image to a face recognition system. In this paper, we propose a new method which predicts high-resolution images and the corresponding features simultaneously. More specifically, we propose ldquofeature hallucinationrdquo to project facial images with low-resolution into an expected feature space. As a result, the proposed method does not require super-resolution as an explicit preprocessing step. In addition, we explore a constrained hallucination that considers the local consistency in the image grid. In our method, we use the index of local visual primitives as features and a block-based histogram distance to measure the similarity for the face recognition. Experimental results on FERET face database verify that the proposed method can improve both visual quality and recognition rate for low-resolution facial images.
A digital multiplexing and real-time refresh dimming control circuit used in LED driver for multiple LED strings

This paper presents a digital dimming control circuit used in a light-emitting diode (LED) driver, allowing it to dim multiple LED strings with only two input ports which receive serial data accompanied with synchronous clock. A multiplexing technique is used to simplify the control circuit, using one DAC to transfer all the dimming messages for each string, and a real-time refresh technique is used to make the transferred dimming voltage keep a high accuracy all the time. The circuit is friendly compatible with the linear current regulator and pulsewidth modulation (PWM) dimming methods. To get a precise dimming control, we build a 10-bit segment R-2R DAC. The simulation results show the dimming voltages for each LED string keep the errors less than 0.5LSB compared with the designed voltages.
An Efficient Reference Frame Storage Scheme for H.264 HDTV Decoder

This paper proposes an efficient reference frame storage scheme for HDTV VLSI decoder to reduce external memory bandwidth requirement. The proposed scheme consists of the pixel duplication mechanism and the L-C (luma-chroma) correlated mapping method. Pixel duplication completely eliminates the possibility of an access crossing word boundary and therefore substantially increases the memory bandwidth efficiency. L-C correlated mapping exploits address relationships between the luma and chroma reference pixels and largely reduces bank conflict overhead of memory accesses. The two mechanisms combined together efficiently improve the bandwidth usage: up to 47% bandwidth in worst case is saved compared with the previous schemes, and 25% in average case
Low bit-rate video coding via mode-dependent adaptive regression for wireless visual communications

In this paper, a practical video coding scheme is developed to realize state-of-the-art video coding efficiency with lower encoder complexity at low bit-rate, while supporting standard compliance and error resilience. Such an architecture is particularly attractive for wireless visual communications. At the encoder, multiple descriptions of a video sequence are generated in the spatio-temporal domain by temporal multiplexing and spatial adaptive downsampling. The resulting side descriptions are interleaved with each other in temporal domain, and still with conventional square sample grids in spatial domain. As such, each side description can be compressed without any change to existing video coding standards. At the decoder, each side description is first decompressed, and then reconstructed to original resolution with the help of the other side description. In this procedure, the decoder recover the original video sequence in a constrained least squares regression process, using 2D or 3D piecewise autoregressive model according to different prediction modes. In this way, the spatial and temporal correlation is sufficiently explored to achieve superior quality. Experiment results demonstrate the proposed video coding scheme outperforms H.264 in rate-distortion performance at low bit-rates and achieves superior visual quality at medium bit-rates as well.
Ensemble of Piecewise FDA Based on Spatial Histograms of Local (Gabor) Binary Patterns for Face Recognition

Spatial histogram of local binary pattern (LBP) and local Gabor binary pattern (LGBP) has been successfully applied to face recognition and achieved state-of-the-art performance. Both LBP and LGBP utilize traditional histogram matching method such as histogram intersection for face classification. In this paper, we propose a statistical extension for L(G)BP similarity computation by introducing Fisher discriminant analysis (FDA) of the L(G)BP spatial histogram "features". More than a simple application of FDA, we have constructed ensemble of piecewise FDA (EPFDA) classifiers, each of which is designed using one segment of the entire spatial histogram features. We show that this extension not only greatly reduces the feature dimension but also brings very impressive performance improvement. Especially, we have made a large step to recognizing all the faces in the standard FERET face database
A serially-connected compensator for eliminating the unbalanced three-phase voltage impact on wind turbine generators

Untransposed transmission lines, unbalanced tap changer operations, and unbalanced loading in weak distribution lines can cause unbalanced-voltage conditions. The resulting unbalanced voltage at the point of interconnection affects proper gird integration and reduces the lifetime of wind turbines due to power oscillations, torque pulsations, mechanical stresses, energy losses, and uneven and overheating of the generator stator winding. This work investigates the dynamic impact of unbalanced voltage on the mechanical and electrical components of integrated Fatigue, Aerodynamics, Structures, and Turbulence (FAST) wind turbine generation systems (WTGs) of Type 1 (squirrel-cage induction generator) and Type 3 (doubly-fed induction generator). To alleviate this impact, a serially-connected compensator for a three-phase power line is proposed to balance the wind turbine-side voltage. Dynamic simulation studies are conducted in MATLAB/Simulink to compare the responses of these two types of wind turbine models under normal and unbalanced-voltage operation conditions and demonstrate the effectiveness of the proposed compensator.
Face recognition based on non-corresponding region matching

In previous works of face recognition, similarity between faces is measured by comparing corresponding face regions. That is to say, matching eyes with eyes and mouths with mouths etc‥ In this paper, we propose that face can be also recognized by matching non-corresponding facial regions. In another word face can be recognized by matching eyes with mouths, for example. Specifically, the problem we study in this paper can be formulated as how to measure the possibility whether two non-corresponding face regions belong to the same face. We propose that the possibility can be measured via canonical correlation analysis. Experimental results show that it is feasible to recognize face via non-corresponding region matching. The proposed method provides an alternative and more flexible way to recognize faces.
Research on client behavior pattern recognition system based on Web log mining

With the explosive growth of data available on the World Wide Web, the sheer volume of traffic is kept on the enterprise's Web site. Discovery and analysis of useful information from the World Wide Web becomes a practical necessary. Web Log Mining is the application of Data Mining techniques to discover Client behavior patterns from Web data in order to understand and serve the needs of Web. In the article we will introduce the method how to use data mining technique to excavate the client behavior pattern from Web log file, and play an emphasis on analyzing client behavior pattern recognition system and its application, so as to help enterprises obtain client information conveniently and automatically.
Compressive Sampling-Based Image Coding for Resource-Deficient Visual Communication.

In this paper, a new compressive sampling-based image coding scheme is developed to achieve competitive coding efficiency at lower encoder computational complexity, while supporting error resilience. This technique is particularly suitable for visual communication with resource-deficient devices. At the encoder, compact image representation is produced, which is a polyphase down-sampled version of the input image; but the conventional low-pass filter prior to down-sampling is replaced by a local random binary convolution kernel. The pixels of the resulting down-sampled pre-filtered image are local random measurements and placed in the original spatial configuration. The advantages of the local random measurements are two folds: 1) preserve high-frequency image features that are otherwise discarded by low-pass filtering and 2) remain a conventional image and can therefore be coded by any standardized codec to remove the statistical redundancy of larger scales. Moreover, measurements generated by different kernels can be considered as the multiple descriptions of the original image and therefore the proposed scheme has the advantage of multiple description coding. At the decoder, a unified sparsity-based soft-decoding technique is developed to recover the original image from received measurements in a framework of compressive sensing. Experimental results demonstrate that the proposed scheme is competitive compared with existing methods, with a unique strength of recovering fine details and sharp edges at low bit-rates.
Fuzzy Logic energy management strategy for Fuel Cell/Ultracapacitor/Battery hybrid vehicle with Multiple-Input DC/DC converter

Battery hybrid power systems represent a promising architecture to satisfy the energy requirements for road vehicles. When the primary power source is a Fuel Cell, the objective of an energy management strategy is to optimize the hydrogen consumption as well as the efficiency without compromising the performance of the overall system. In order to achieve these goals, Fuzzy Logic has been chosen as a control strategy in this study. Using this technology is a reasonable option to achieve an adequate solution of the problem due to the fact that it can deal simultaneously with a considerable amount of variables. Besides, a simulation environment has been developed for the sake of testing the control strategies; it includes models for the power supply and energy storage devices, the power electronics and the vehicular power demand.
A low-power 14-bit two-stage hybrid ADC for infrared focal plane array detector

This paper presents a low-power 14-bit hybrid incremental Σ-Δ/cyclic analog-to-digital converter (ADC) based on pseudo-differential operational amplifier, which is designed for the readout circuit of infrared focal plane array detector. This two-stage hybrid ADC employs an incremental sigma-delta ADC and a cyclic ADC, achieving a good trade-off between accuracy and conversion speed. The two stages share the same analog circuit to reduce area and power consumption. A common-mood feedback module is used to suppress the influence of charge injection, and the effectiveness is demonstrated by detailed theoretical analysis and simulation result. A test chip is fabricated in 0.18 μm CMOS technology. The hybrid ADC in each column is performed in parallel with power consumption of 218.813 μW The simulation result reveals the effective number of bits (ENOB) is 13.775 bits.