nils-herrmann/clean_scirepeval huggingface dataset:
Using cognitive radio principles for wireless resource management in home networking

The demand for higher data rates, capacity and better quality-of-service is constantly growing for home networks. Therefore, there is a pressing need for efficient use of wireless network resources. In this context, the application of cognitive radio principles that enable network nodes to characterize their environment and control their resources based on the acquired knowledge, is the prominent solution for next generation home networks. In this paper we present an architecture and a prototype implementation based on these principles. The proposed system is able to autonomously optimize the performance of network nodes in a dynamic environment according to the goals, restrictions and policy regulations formulated by network stakeholders. The obtained results show the momentous and suitability of the cognitive framework for home networking.
Covert Communication in Wireless Relay Networks

Covert communication aims to shield the very existence of wireless transmissions in order to guarantee a strong security in wireless networks. In this work, for the first time we examine the possibility and achievable performance of covert communication in one- way relay networks. Specifically, the relay opportunistically transmits its own information to the destination covertly on top of forwarding the source's message, while the source tries to detect this covert transmission to discover the illegitimate usage of the recourse (e.g., power, spectrum) allocated only for the purpose of forwarding source's information. The necessary condition that the relay can transmit covertly without being detected is identified and the source's detection limit is derived in terms of the false alarm and miss detection rates. Our analysis indicates that boosting the forwarding ability of the relay (e.g., increasing its maximum transmit power) also increases its capacity to perform the covert communication in terms of achieving a higher effective covert rate subject to some specific requirement on the source's detection performance.
Adaptive windowing for optimal visualization of medical images based on normalized information distance

There has been a growing recent interest of applying Kol-mogorov complexity and its related normalized information distance (NID) measures in real-world problems, but their application in the field of medical image processing remains limited. In this work we attempt to incorporate NID in the design of windowing operators for optimal visualization of high dynamic range (HDR) medical images, where predefined intensity interval of interest needs to be mapped to match the low dynamic range (LDR) of standard displays. By approximating NID using a Shannon entropy based method, we are able to optimize parametric windowing operators to maximize the information similarity between the HDR image and the LDR image after mapping. Experimental results demonstrate promising performance of the proposed approach.
OFCDM: a promising broadband wireless access technique

Future mobile communication systems aim to provide extremely high-speed data transmission, especially in the downlink. The broadband orthogonal frequency- and code-division multiplexing system with two-dimensional spreading (time and frequency domain spreading) is becoming a very promising technique for highspeed wireless communications due to its advantages over OFDM. This article presents the basic structure and main functions of the OFCDM system. A nonsequential code assignment scheme is introduced. The novel detection method for the OFCDM, called hybrid multi-code interference cancellation and minimum mean square error detection, is described. The application of advanced techniques to the OFCDM, such as turbo coding and MIMO, is also discussed. It is shown in this article that OFCDM is superior to OFDM.
Narrowband interference suppression in time-hopping impulse radio ultra-wideband communications

Ultra-wideband (UWB) technology has been considered an innovative solution for future short-range high-speed wireless communications. Interference suppression is important for the UWB devices to operate over spectrum occupied by narrowband systems. In this paper, the use of a notch filter in time-hopping impulse radio (TH-IR) for UWB communication is considered, where a Gaussian monopulse is employed with pulse position modulation. Lognormal channel fading is assumed, and a complete analytical framework is provided for the performance evaluation of using a transversal-type notch filter to reject narrowband interference (NBI). A closed-form expression of bit-error probability is derived, and the numerical results show that the use of a notch filter can improve the system performance significantly. Furthermore, a performance comparison between TH-IR and multicarrier code-division multiple-access (MC-CDMA) UWB systems is made under the conditions of the same transmit power, the same data rate, and the same bandwidth. It is shown that in the presence of NBI, the TH-IR system and MC-CDMA system achieve similar performance when both use a notch filter
SSIM-Based Coarse-Grain Scalable Video Coding

We propose an improved coarse-grain scalable video coding (SVC) approach based on the structural similarity (SSIM) index as the visual quality criterion, aiming at maximizing the overall coding performance constrained by user-defined quality weightings for all scalable layers. First, we develop an interlayer rate-SSIM dependency model, by investigating bit rate and SSIM relationships between different layers. Second, a reduced-reference SSIM-Q model and a Laplacian R-Q model are introduced for SVC, by incorporating the characteristics of hierarchical prediction structure in each layer. Third, based on the user-defined weightings and the proposed models, we design a rate-distortion optimization approach to adaptively adjust Lagrange multipliers for all layers to maximize the overall rate-SSIM performance of the scalable encoder. Experiments with multiple layers, different layer weightings, and various videos demonstrate that the proposed framework can achieve better rate-SSIM performance than single layer optimization method, and provide better coding efficiency as compared to the conventional SVC scheme. Subjective tests further demonstrate the benefits of the proposed scheme.
A fractal-based hybrid image coding system

The interest in image compression by means of fractal techniques has been steadily growing in recent years since Jaquin proposed a fully automatic image compression algorithm called fractal block coding (FBC). In this paper, we introduce a hybrid system where only the edge region of the image is coded by fractal transform and the smooth region is modeled by other techniques. The non-fractal coded region is used to help the coding of the fractal coded region, so that the fractal coded region can be represented by fewer bits. Experiments show that the overall coding efficiency is improved.
Synergetic p+n Field-Effect Transistor Circuits for ppb-Level Xylene Detection

Nowadays, xylene is not only one major air pollutant which threats human health even if its concentration is lower than the human olfactory threshold of 470 ppb, but also one of the typical gases exhaled by the lung cancer patients with a criterion of 10–20 ppb. However, <italic>in situ</italic> detection of the ppb-level xylene for air quality monitoring and breath analysis remains challenging using the easily fabricated and low cost metal oxide semiconductor gas sensors. Herein, a synergetic p+n field effect transistor (FET) amplification circuit is designed to detect the ppb level xylene. By optimizing the load resistor (<inline-formula> <tex-math notation="LaTeX">$R_{L}$ </tex-math></inline-formula>) and the p- and n-FET coupling effect, a magnification factor (~7.5) is obtained. This amplification circuit decreases the detection limit of TGS2602 sensor to ~10 ppb xylene with apparent response of about 2.3 and voltage change of >0.5 V, promising for air quality monitoring (the highest permissive limit of 42 ppb) and breath disease analysis (threshold of lung cancer 10–20 ppb). The mechanism is that the matched couple of p + n FETs work synchronically when their (<inline-formula> <tex-math notation="LaTeX">$R_{\mathrm {L}} + R_{\mathrm {FET}}) - I$ </tex-math></inline-formula> curves nearly coincide with each other. All those results show the prospect of ppb level gas detection with MOX sensors using the synergetic p+n FET amplification circuit.
Downlink transmission of broadband OFCDM systems-part IV: soft decision

In this paper, the performance of turbo-coded orthogonal frequency and code-division multiplexing (OFCDM) systems is investigated with soft multicode interference (MCI) cancellation and minimum mean-square error (MMSE) detection for downlink transmission in future high-speed wireless communications. To regenerate the soft interference signal, the conventional turbo decoding algorithm must be modified to provide log-likelihood ratio (LLR) values for all coded bits. Based on the LLR outputs of turbo decoder, two soft-decision functions are proposed, called LLR-soft-decision and Gaussian-soft-decision functions. The Gaussian assumptions used for deriving these two soft functions are verified by simulation results, and simple methods are proposed to estimate parameters used in the soft functions in practical systems. By means of computer simulations, the performance of soft MCI cancellation is studied extensively and compared with that of hard ones. It is shown that in a highly frequency-selective channel, soft MCI cancellation and MMSE detection can significantly improve the performance of turbo-coded OFCDM systems. Two iterations in turbo decoding are sufficient for both hard and soft-decision functions. The proposed soft-decision functions outperform the hard-decision function with various channel conditions and system parameters, such as the channel correlation, the quality of channel estimation, the number of iterations in turbo decoding and the frequency-domain spreading factor (NF). Furthermore, the Gaussian-soft-decision function provides better performance than the LLR-soft-decision function. Finally, although frequency diversity gain is saturated for large channel correlation when NF is large as in , the gain increases further with increasing NF for small channel correlation even when NF is large
A Fast Algorithm for Constructing FP_Tree

Recently, most of the studies on mining frequent patterns focus on improving the efficiency of frequent itemtsets generations, but the I/O cost of database scanning has been a bottle-neck problem in data mining. Many algorithms proposed recently are based on apriori and FP tree, and the FP growth algorithm based on FP tree is more efficient than Apriori because the candidates are not generated. But the construction of FP tree may spend much time. Therefore, the goal of our research is to propose a fast algorithm. In this paper, Level FP_tree that is constructed level by level (abbreviate LFP tree) is proposed. The algorithm contains two main parts. The first is to scan the database only once for generating equivalence classes of each item. The second is to delete the non-frequent items and rewrite the equivalence classes of the frequent items, and then construct the LFP tree. Experimental results have proved that LFP tree is more efficient and scalable than FP tree.
Optimum sub-packet transmission for turbo-coded hybrid ARQ systems

Turbo codes are popular for their near-Shannon capacity of bit-error-rate (BER) at low signal-to-noise ratio (SNR) with long packet lengths. They have been proposed in automatic-repeat-request (ARQ) systems as the forward-error correction (FEC) codes. Although sub-packet schemes were proposed in ARQ systems, optimum sub-packet transmission is more effective to maximize throughput in a dynamic channel. Sub-packet schemes can provide additional error correction capability with iterative turbo decoding algorithms. An efficient method is proposed to estimate the optimum number of sub-packets, and adaptive sub-packet schemes, i.e., that enables a system to employ different optimum numbers of sub-packets under variable conditions, are suggested to achieve the maximum throughput of the system. Simulations show that the adaptive sub-packet scheme is effective at moderate SNR, e.g. from 2.6 dB to 5.0 dB, and can provide higher throughput than conventional packet schemes.
Performance of hybrid DS/SFH spread-spectrum multiple-access for indoor wireless communications

The performance of noncoherent reception in hybrid direct-sequence/slow-frequency-hopped (DS/SFH) spread-spectrum multiple access (SSMA) communication systems operating through indoor wireless multipath and fading channels is investigated. The system with differential-phase-shift keying (DPSK) modulation and predetection combining is examined. Approximations are obtained for the multiuser probability of error by using a Gaussian approximation for the multiple-access and multipath interference.<<ETX>>
An analytic channel potential based model for dynamic depletion surrounding-gate mosfets with arbitrary doping level

In this paper an analytic channel potential-based model is proposed to predict the dynamic depletion behavior of surrounding-gate (SRG) MOSFETs with arbitrary doping level. The key input voltage equation is derived out by solving Poisson's equation approximately with arbitrary doping in the cylindrical coordinate. Combined with the surface-centric potential relationship, the electrostatic potential solution along the radius of both intrinsic and heavily doped SRG is obtained. With the potential solutions at the source and drain sides of the channel, the analytic drain current model is provided to calculate the current characteristics of the SRG MOSFET. The presented model can realize transition from partial depletion to full depletion of SRG MOSFET, which is validated by numerical simulation.
The Status and Trends of International Competitiveness of China's Labor Force

For a long time, the abundant labor resource is a solid foundation for the development of China's foreign trade. But industry's competitiveness that simply relies on the comparative advantages of labor would weaken gradually. On the perspective of China's labor costs, this paper analyzes the current situation and the trend of China's labor competitiveness. By combining average wage with labor productivity together, China's labor cost is not a significant advantage. Labor competitiveness is affected by combined effects of various factors. Single labor comparative advantage has been weakening continuously and is not core-competitiveness for China to stand in international market. It is necessary to promote the true value of labor resource and transform comparative advantage into competitive advantage by adjustment of state policies and optimization of industrial structures.
Hybrid DS/SFH Spread-Spectrum Multiple Access with Predetection Diversity and Coding for Indoor Radio

The authors derive close upper and lower bounds on the average bit error probability for hybrid direct-sequence/slow-frequency-hopped spread-spectrum multiple-access (DS/SFH-SSMA) systems with noncoherent DPSK demodulation, using predetection diversity (selection combining and equal gain combining) in conjunction with interleaved channel coding (Hamming
Unsupervised Recognition and Characterization of the Reflected Laser Lines for Robotic Gas Metal Arc Welding

Unsupervised recognition of the reflected laser lines from the arc-light-modified background is prerequisite for the subsequent measurement and characterization of the weld pool shape, which is of great importance for the modeling and control of robotic arc welding. To facilitate the unsupervised recognition, the reflected laser lines need to be segmented as accurate as possible, which requires the segmented laser lines to be as continuous as possible to decrease the adverse effect of the noise blobs. In this paper, the intensity distribution caused by the arc light in the captured image is modeled. Based on the model, an efficient and robust approach is proposed, and it comprises six parts: reduction of the uneven image background by a difference operation, spline enhancement to remove the fuzziness, a gradient detection filter to eliminate the uneven background further, segmentation by an effective threshold selection method, removal of the noise blobs adaptively, and clustering based on the online computed slope of the laser line. After the laser line is clustered, a second-order polynomial is fitted to it. Finally, the weld pool is characterized by the parameters of the clustered laser line and its fitted polynomial. Experimental results verified that the proposed approach for unsupervised reflected laser line recognition is significantly superior to the state-of-the-art approach in terms of recognition accuracy.
Objective Quality Assessment for Multiexposure Multifocus Image Fusion

There has been a growing interest in image fusion technologies, but how to objectively evaluate the quality of fused images has not been fully understood. Here, we propose a method for objective quality assessment of multiexposure multifocus image fusion based on the evaluation of three key factors of fused image quality: 1) contrast preservation; 2) sharpness; and 3) structure preservation. Subjective experiments are conducted to create an image fusion database, based on which, performance evaluation shows that the proposed fusion quality index correlates well with subjective scores, and gives a significant improvement over the existing fusion quality measures.
Performance analysis of MMSE detectors for high speed VSF-OFCDM

This letter investigates the effect of Doppler frequency shift on the performance of MMSE receivers for high speed variable spreading factor (VSF) orthogonal frequency and code division multiplexing (OFCDM) systems in broadband wireless communications. In VSF-OFCDM systems, the existence of multicode interference (MCI) resulting from multiple code channels occupying the same bandwidth degrades the performance. A full MMSE receiver is analytically studied in this letter, exploiting correlation properties among transmitted data on different subcarriers to combat the MCI. Furthermore, considering the fact that the fast time-varying fading destroys the orthogonality of the time domain spreading codes and thus introduces time domain MCI, its effect on system performance is evaluated accurately. It is also shown that it is expected to use time domain spreading factor NT of 8 for a large range of Doppler frequencies, and frequency domain spreading factor as large as possible, especially in high signal to noise ratio. Moreover, in order to improve performance, the pilot channel should occupy around 20% to 25% of the total transmitted power for a large range of Doppler.
Gradient-based surface reconstruction using compressed sensing

Surface reconstruction from measurements of spatial gradient is an important computer vision problem with applications in photometric stereo and shape-from-shading. In the case of morphologically complex surfaces observed in the presence of shadowing and transparency artifacts, a relatively large number of gradient measurements may be required for accurate surface reconstruction. Consequently, due to hardware limitations of image acquisition devices, situations are possible in which the available sampling density might not be sufficiently high to allow for recovery of essential surface details. In this paper, the above problem is resolved by means of derivative compressed sensing (DCS). DCS can be viewed as a modification of the classical compressed sensing (CS), which is particularly suited for reconstructions involving image/surface gradients. We demonstrate that using DCS results in substantial data savings as compared to the standard (dense) sampling, while producing estimates of higher accuracy and smaller variability, as compared to CS-base estimates. The results of this study are further supported by a series of numerical experiments.
Geometric correction error of SPOT5 remotely sensed image

Compared to aviation survey, the highresolution images of SPOT5 make it cost-efficient for remote sensing based land use mapping and land use dynamic monitoring at 1:10,000 scales, and the key technical problem is that whether the geometric correction error of the image is within the error limitation at this scale. In order to obtain the geometric correction precision and provide the precision reference for the applications of SPOT5 image to land use, one case study was taken in Nanxun (plain area) of Huzhou city. Based on the SPOT5 images acquired and the ground control points (GCPs) and check points taken by differential GPS through field survey, the error of self-correction and independentcorrection of images were analyzed. Besides X error, Y error and total RMS, other indices such as CE90 and CE95, maximal point position error, <3 m% and <5 m%, were used to evaluate the effects of different geometric correction models and different amount of GCPs to geometric correction. The best geometric correction results we got from SPOT5 images of plain area were X-2 m, Y-1.8 m, total RMS-2.8 m, maximal point position error-5.5 m, CE90-4.1 m, CE95-4.9 m, 75% of points’ position error <3 m and 98% of points’ position error <5 m. Based on the above results, a scheme for geometric correction of SPOT5 image was put forward.
No-reference image sharpness assessment based on local phase coherence measurement

Sharpness is one of the most determining factors in the perceptual assessment of image quality. Objective image sharpness measures may play important roles in the design and optimization of visual perception-based auto-focus systems and image enhancement, restoration and compression algorithms. Here we propose a new sharpness measure where sharpness is identified as strong local phase coherence evaluated in the complex wavelet transform domain. Our test using the LIVE blur database shows that the proposed algorithm correlates well with subjective quality evaluations. An additional advantage of our approach is that other image distortions such as compression, median filtering and noise contamination that may affect perceptual sharpness can also be detected.
Working quantum efficiency of cdte solar cell

For p-CdTe/n-CdS solar cell, it is reported that the quantum efficiency and the collection efficiency are not only wave length dependent but also most importantly voltage dependent, since the CdTe solar cell is believed to be the diode which has non-shallow acceptors and deep levels where the roles of these levels are not clear. In this study, the quantum efficiency of CdTe solar cell with various optical biases, which is titled as “Working Quantum Efficiency (WQE)”, is measured. The result is compared with industrialized amorphous silicon solar cell. Simulation models are given to explain those measurements. The result shows the measurements of WQE is one of important evaluations for CdTe solar cell as well as it can contribute to its characterization and improvement.
Two-stage acquisition for time-hopping impulse radio communications

Time-hopping impulse radio is a promising radio technology for networks delivering extremely high data rates at short ranges. But the use of extremely short duration pulses makes synchronization task more difficult. In this paper a novel acquisition with two-stage serial search noncoherent correlator for ultra wideband signal is proposed. This acquisition scheme gets chip timing synchronization, and aligns phase of the local time-hopping code in two stages successively. With the aid of flow-graph approach, the analytical expressions have been presented for the mean acquisition time and probability of acquisition. Numerical results in a slow fading channel show that the novel two-stage acquisition method can offer much shorter mean acquisition time and much higher probability of acquisition than that of the conventional acquisition.