nils-herrmann/clean_scirepeval huggingface dataset:
Two-dimensional face recognition algorithms in the frequency domain

Principal component analysis (PCA), well-known for its compaction capability and robustness against noise, is a widely used technique for face recognition. However, it has major drawbacks: (i) losing image details, (ii) having a large time complexity and (iii) suffering from adverse effect of intra-class pose variations. To overcome the last drawback in PCA, Fourier magnitude (FM-PCA) has been proposed in which Fourier magnitudes have been used for feature extraction. Furthermore, to address the other two drawbacks, two-dimensional PCA (2DPCA) algorithms have been proposed. In this paper, to overcome the problems (i) and (ii) in FM-PCA and the problem (iii) in 2DPCA algorithms, Fourier magnitude 2DPCA algorithms which incorporate the advantages of FM-PCA and 2DPCA algorithms are developed. Extensive simulations on the ORL database confirm the effectiveness of the proposed algorithms in providing higher accuracy over PCA, FM-PCA and 2DPCA algorithms with a much smaller complexity compared to that of FM-PCA.
Residue-to-binary number converters for three moduli sets

In this paper, residue-to-binary number converters for the special moduli sets (2n,2n+1,2n+2) and (2n-1,2n,2n+1) are studied. Errors in a previous publication are pointed out. New and more efficient converters for both the special moduli sets are proposed. Larger multipliers in previous methods are replaced by smaller multipliers and adders. The new converters use about one-half of the hardware required by the previous methods.
Rate-optimal static scheduling of DSP data flow graphs onto multiprocessors using circuit contraction

This paper is concerned with the compile-time (static) scheduling of data flow graphs (DFGs) onto multiprocessor systems. It mainly concentrates on producing a rate-optimal time schedule that achieves the minimum iteration period, known as the iteration period bound. A combinatorial theory is developed to produce a rate-optimal time schedule for a fully specified DFG. The DFG is first converted to a critical graph by making all its circuits critical. Next, it is transformed into an acyclic graph through a sequence of circuit contractions. An algorithm is then proposed which achieves the time scheduling of the given DFG by first scheduling the acyclic graph, followed by a scheduling of the critical circuits in an order which is reverse to that of their contraction.
Self-synchronized signal controlled constrained notch filter for rejection of nonstationary interference

A novel signal controlled constrained notch filter (SC-CNF) structure with global feedback is presented. The SC-CNF is combined with an adaptive linear enhancer to retrieve a multitone signal corrupted by a strong nonstationary FM interference. Using a time-warping technique, the SC-CNF, by its nature time-varying, is transformed into a CNF which is time variant. Such transformation is implemented by nonequally spaced sampling (NESS) of the input mixture. A closed-loop system is proposed to improve the strategy of NESS. By exploiting the self-synchronization process, nearly complete rejection of FM interference is achieved. The condition for the occurrence of self-synchronization is obtained. The self-synchronized SC-CNF provides significant improvement (up to 30 dB) of the signal-to-interference ratio of the entire system output.<<ETX>>
Bispectrum estimation via autoregressive modeling: a group delay approach

A new method of bispectrum estimation by an AR (autoregressive) model has been proposed for a signal which is the output of a mixed-phase system driven by a non-Gaussian noise. This is achieved by relating the bispectrum phase and magnitude to the system group delay functions. The maximum and minimum phase property of the group delay functions makes AR bispectrum estimation possible, since there exists a direct relation between the cepstral and AR coefficients. The proposed method uses only the bispectrum information and is applicable for moving average (MA) or AR or ARMA system with either mixed-phase poles or mixed-phase zeros or both. Unlike some of the existing methods, it uses all the bispectral information and does not involve any solution of a system of equations. The method has been illustrated for MA and ARMA systems using sample root mean square error as the performance index.<<ETX>>
Stability of mutually inverse rational 2-D digital transfer functions

This brief considers the open problem concerning the BIBO stability of mutually inverse 2-D digital filters in the presence of nonessential singularities of the second kind on T/sup 2/. Necessary and sufficient conditions are obtained for the BIBO stability of mutually inverse pairs of 2-D digital filters having such singularities on T/sup 2/. Several illustrative examples are considered.
A multiplication-free transform for image compression

In this paper, we propose an efficient 8 times 8 multiplication-free transform operator for image compression by appropriately introducing some zeros in the 8 times 8 signed DCT matrix. We also develop fast algorithms for the computation of the proposed transform as well as for its inverse. Compared to the existing 8 times 8 approximated DCT matrices, it is shown that savings of 12.5% in the number of additions can easily be achieved using the proposed transform operator without noticeable degradations in the reconstructed images. We also present simulations on some standard test images to show the efficiency of the proposed transform in image compression.
Formulas for parameter scaling in the McClellan transform

In using the original 1-D to 2-D McClellan transform cos{\omega}= F(cos{\omega}_1,cos{\omega}_2) , scaling of the transform parameters  is necessary to guarantee that |F| \leq 1 . In a recent letter [7], we have presented extremely simple formulas for the scaling factors, then proposed a modified transform which not only is scaling-free but also contains one fewer parameter than the original transform. The work in  however is restricted only to common elliptical isopotential contours. In this paper, we analyse the problem for more general cases.
On the realization of an all-pass or a notch filter

It is shown that it is possible to realize either a second-order all-pass or a notch filter by a structure consisting of a grounded operational amplifier and two RC one-ports, Y 1 =G 1 +sC 1 and Y 2 =[R 2 +(1/sC 2 )]-1. It is also shown that these filters may be realized by the same structure with Y 1 and Y 2 interchanged. These realizations possess minimum sensitivity with respect to the amplifier gain.
A study of the residue-to-binary converters for the three-moduli sets

In this paper, a detailed study on the four three-moduli sets reported in the literature is carried out from the point of view of the hardware complexity and speed of their residue-to-binary (R/B) converters. First, a new formulation of the Chinese remainder theorem is proposed that reduces the size of the modulo operation. Then, the proposed formulation is applied to derive, in a simple and unified manner, R/B conversion algorithms for three of the sets. Further, using this formulation, a new algorithm along with two corresponding R/B converters for the fourth set is proposed; one of these converters is area efficient while the other is speed efficient. Next, the best R/B converter(s) for each of the sets is chosen based on the hardware complexity and/or speed. These converters are implemented for 8, 16, 32, and 64-bit dynamic ranges, using CMOS VLSI technology. Based on a post-layout performance evaluation for the VLSI implementations of the chosen converters, it is shown that in order to represent 8-, 16-, 32-, and 64-bit binary numbers, the moduli set {2/sup n/,2/sup n/+1,2/sup n/-1} provides the fastest R/B converter and requires the smallest area.
Economic implementation of a high performance FDM system using the sequence discriminator

An economic design approach to high-selectivity single-sideband modulation and demodulation using a polyphase network sequence discriminator is presented. The tolerance requirements on capacitors to manufacture the circuits have been relaxed to a practical value of +or-1.0% from the existing state of the art of +or-0.2% through the introduction of a new trimming procedure, which can be used for other circuit designs. New circuits using the buffered polyphase network are proposed. The circuits use capacitors of the same nominal value, which simplifies the manufacture of the filter. These circuits allow image band rejection in excess of 62 dB and a passband ripple less than +or-0.25 dB with +or-1.0% capacitors. The filters were manufactured on a 1-in*2.5-in substrate using thick-film technology. The overall yield of the manufactured network is close to 100%.<<ETX>>
An on-line CORDIC based 2-D IDCT implementation using distributed arithmetic

This paper presents a cost-effective VLSI architecture for a two-dimensional (2-D) inverse discrete cosine transform (IDCT) core based on a modified on-line CORDIC algorithm. In order to have a low hardware complexity and to provide a good performance, the proposed design is based on the row-column decomposition approach and distributed arithmetic (DA). By reformulating the 1-D IDCT functions using the CORDIC approach, the proposed design requires about 60% less ROM than the conventional DA-based IDCT without using CORDIC. In our architecture the on-line algorithm is used to further reduce the area and to enhance the computation speed. The core operates on blocks of 8/spl times/8 pixels, with 12-bit and 8-bit precision for inputs and outputs, respectively. The proposed design has been synthesized by using 0.35-/spl mu/m CMOS technology. The simulation results show that the core for IDCT can run at 150 MHz with 60 Mpixel/s throughput, while meeting the requirement of the H.26x standard.
Accurate DOA estimation via sparse sensor array

An accurate direction-of-arrival (DOA) estimation algorithm with sparse sensor array is proposed. By dividing the nonuniform linear sparse array (NLSA) into two uniform linear sparse arrays (ULSA), the subarray response vectors yield a property of rotational invariance in the estimation of rough DOA without ambiguity using the so-called generalized ESPRIT. According to the estimated rough DOA, the accurate DOA of each source is then obtained by the proposed alternating null-steering technique (ANST). Simulation results that demonstrate the performance of the algorithm are provided.
Design of OTA-C oscillators and current-mode filters using network transposition

OTA-C filters have received a lot of attention. for high frequency continuous-time applications. The design of OTA-C filters has traditionally been considered as voltage mode signal processing. Over the last decade, current mode signal processing has emerged as an important class of analogue circuitry because of the simplicity associated with implementing basic operations such as signal summing and replication, and the potential to operate at higher signal bandwidths and lower voltage than in the voltage mode approach. A number of researchers have investigated as to how to design current mode filters. For instance, Sun and Fidler have proposed current-mode two-integratorloop dual-output OTA-C filters and current-mode multiple-loop feedback filters. In principle, various current-mode filter structures can be generated by these systematic methods. However, complicated voltage/current calculation is needed for loop analysis or approaches requiring solution of nonlinear equations are required to solve coefficient matching equations associated with the feedback matrix. However, the principle of network transposition, proposed by Bhattacharyya and Swamy as early as 1971, can be used to advantage to derive, in a straightforward manner, current-mode OTA-C filter structures from well-known OTA-C voltage-made filter structures. Application of network transposition is extended to oscillators, and several new oscillator circuits derived from existing oscillator circuits are given. Furthermore, it is shown that the application of network transposition to differential-input, differential-output networks leads to the realization of fully differential current mode filters and oscillators. As illustrations, several new current-mode fully differential OTA-C filters and oscillators are derived using network transposition. Experimental results on several voltage-mode and current-mode filters and oscillators, built using commercial OTA (LMI 13700) devices, capacitors and resistors will be presented.
Channel estimation of pulse-shaped multiple-input multiple-output orthogonal frequency division multiplexing systems

Most of the existing multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) channel estimation methods do not take into account the effect of the pulse-shaping filter in the transmitter nor of the matched filter in the receiver, thus leading to an estimation solution for the composite channel including the pulse-shaping and matched filters, instead of the pure wireless channel. This solution is not sufficiently accurate because of the extra length of the composite channel induced by the two filters especially in the scenario with a small pure channel length. In this study, the authors present a novel methodology for the estimation of the pure multipath channels of pulse-shaped MIMO-OFDM systems. By utilising the knowledge of pulse-shaping and matched filters, the authors develop two channel estimation approaches, namely, a semi-blind approach for the sampling duration-based channels, in which the multipath occurs at the sampling instant and a training-based least-square technique for the upsampling duration-based channels where the multipath may occur in a fraction of sampling duration. A number of computer simulation-based experiments are conducted, and these simulation results confirm the efficacy of the proposed approaches.
SVD and ASCII Character Encoding-Based Compression of Multiple Biosignals for Remote Healthcare Systems

Advancements in electronics and miniaturized device fabrication technologies have enabled simultaneous acquisition of multiple biosignals (MBioSigs), but the area of compression of MBioSigs remains unexplored to date. This paper presents a robust singular value decomposition (SVD) and American standard code for information interchange (ASCII) character encoding-based algorithm for compression of MBioSigs for the first time to the best of our knowledge. At the preprocessing stage, MBioSigs are denoised, down sampled and then transformed to a two-dimensional (2-D) data array. SVD of the 2-D array is carried out and the dimensionality of the singular values is reduced. The resulting matrix is then compressed by a lossless ASCII character encoding-based technique. The proposed compression algorithm can be used in a variety of modes such as lossless, with or without using the down sampling operation. The compressed file is then uploaded to a hypertext preprocessor (PHP)-based website for remote monitoring application. Evaluation results show that the proposed algorithm provides a good compression performance; in particular, the mean opinion score of the reconstructed signal falls under the category “very good” as per the gold standard subjective measure.
A multivariable transformation and its use in the synthesis of driving-point functions

A new transformation which converts a multivariable positive real function to another multivariable positive real function is presented and the conditions for the reduction in degree of the resulting positive real function are discussed. Its application to the synthesis of a class of multivariable driving-point functions is discussed. These results are generalized to the synthesis of a class of n -port multivariable driving-point matrices.
A multimicroprocessor system with distributed common memory for real-time digital correlation and spectrum analysis

In this paper software and hardware design of a tightly-coupled multimicroprocessor system with distributed common memory and private memory modules, to compute the values of auto- and cross-correlation functions, to recover signals buried in noise and to compute cross- and auto-power spectral density at 128 points simultaneously on the time delay axis or frequency axis, are described. This multimicroprocessor system has two 16-bit micro-processor boards, a single common bus, a centralized common-memory (CMO) and necessary arbitration logic circuits. To each microprocessor board, a distributed common memory, a private memory, I/O and common-memory-access control circuits are added. The addressing scheme is designed such that any common-memory cell has the same address for all the microprocessors. These software and hardware mechanisms suit the present signal processing application well. The computed results are displayed on an oscilloscope or X-Y recorder.
Statistics of 2-D DT-CWT Coefficients for a Gaussian Distributed Signal

This paper deals with the statistical properties of the two-dimensional dual-tree complex wavelet transform (DT-CWT) coefficients of a Gaussian distributed signal both in the Cartesian and polar forms. The first level of decomposition of the DT-CWT uses the wavelet filters that form only an approximate Hilbert-pair, while those at the higher levels form almost an exact Hilbert-pair. Hence, a significant correlation exists between the quadrature-filtered coefficients of the two trees in the first level of decomposition as compared to the other levels. As a consequence, in the Cartesian representation, the real and imaginary components of the complex coefficients are modeled as independent zero-mean Gaussian having unequal variances for the first level of decomposition and equal variances for the higher levels. In the polar representation, the magnitude components are modeled by a generalized Gamma probability density function (PDF) for the first-level decomposition and a Rayleigh PDF for the higher levels. The corresponding phase components are modeled by an analytic PDF. The Monte Carlo simulations show that the proposed PDFs of the transform coefficients match very well with the empirical ones. It is shown that the moments of the corresponding PDFs closely approximate the estimated sample moments. Finally, two techniques, namely, maximum a posteriori-based estimation and phase-based ridge detection are developed using the proposed PDFs. Simulation studies are carried out showing that the use of the proposed techniques provides improved estimation and detection performance of images in a noisy environment.
Realisation of a 2-dimensional f.i.r. digital filter using separable filters

The scheme for the expansion of a 2-dimensional f.i.r. digital filter function into a sum of separable functions is generalised. Using the generalised procedure a m × m order filter function can be expressed in as many as m!n!/(|m-n| + 1)! ways. Further it is also proved that the number of terms in the expansion will be equal to the rank of the matrix.
On the algorithms for the computation of even discrete cosine transform-2 (EDCT-2) of real sequences

An algorithm based on O/sup 2/DFT (odd-time odd-frequency discrete Fourier transform) is presented for the computation of the EDCT-2 of purely real sequences. Comparison of this algorithm with two others available in the literature shows that it is computationally superior for EDCT-2 evaluation of real sequences (N>8). Its computational advantage is based on its lesser real multiplication requirements.
Realization of a class of two-dimensional analog ladders with applications to wave digital filters

Necessary and sufficient conditions are obtained for the realization of a class of two-variable analog transfer functions. The transfer function is realized as a resistively-terminated two-port consisting of a cascade of P 1 and P 2 -variable lossless two-ports each having all of its transmission zeros at P i =0 or p i =∞ (i=1,2), It is shown how these analog realizations may be used to realize two-dimensional wave digital filters.
Transistor parameters in the avalanche mode

While the literature is quite complete on transistor parameters below the avalanche region and a considerable amount of work has been directed to the region where complete breakdown occurs, the intermediate region has received very little study. This paper deals with the behaviour of the transistor in the border region of avalanche and particularly treats transistors of very high cut-off frequency. This is done in terms of the general four-terminal network parameters. The effects of avalanche on the a cut-off frequency and the maximum frequency of oscillation are discussed by using the admittance parameters and the short circuit current gain,which were measured experimentally. Further, it is shown that operation under avalanche conditions can extend the maximum useful operating frequency
Camouflaged target detection using real-time video fusion algorithm based on multi-scale transforms

In this paper, we propose a novel video fusion algorithm for real-time detection of camouflaged targets. Initially, the targets are detected by using a novel target detection method by applying conventional image thresholding methods in the wavelet domain. The thermal information corresponding to the detected targets are transferred to the output fused image along with the background information by using novel region-based fusion rules. The dominance of the proposed algorithm in terms of the detection of the camouflaged targets is visibly evident from the quantitative and qualitative results of the output fused video.
An approach for computing the radix-2/4 DIT FHT and FFT algorithms using a unified structure

By using an appropriate index mapping and by introducing a unified approach for the development of the radix-2/4 decimation-in-time (DIT) fast Hartley transform (FHT) and complex-valued fast Fourier transform (FFT) algorithms, it is shown that there is a close relationship between the structures of the two algorithms. As a result of this close relationship, it is shown that only a single general butterfly is sufficient to implement the two algorithms. This type of relationship is of significant importance for software and hardware implementations of the algorithms, since this relationship, along with the fact that the DHT (discrete Hartley transform) is an efficient alternative to the DFT (discrete Fourier transform) for real data, makes it possible for a single software or hardware module to be used for the computation of the DHT as well as for the computation of the forward and inverse DFTs for real- or complex-valued data.
Detection of epileptic seizures in stereo-EEG using frequency-weighted energy

This paper proposes a new algorithm for seizure detection based on the evolution-like characteristics of a seizure. Most of the existing algorithms for automatic detection of the epileptic seizures in electroencephalograms (EEG) rely upon some pre-defined/patient-tunable detection threshold to classify the data as normal or abnormal. In this paper, we present a method for seizure detection in stereoencephalograms (SEEG) using frequency-weighted energy. The method does not require a threshold or any a priori information about the seizure for its detection. The method is gradient-based and any activity that exceeds the minimum duration satisfying our criteria is considered as a potential seizure activity. The performance of the algorithm is evaluated on 100 hours of single channel SEEG data obtained from five different patients. An overall sensitivity of 96.6% and a false detection rate of 0.21/h is obtained on the complete data.