Wyniki wyszukiwania - BazTech

1

Improving Performance of MC-CDMA Systems Using UTTCM Channel Coding

Bendjillali Ridha Ilyas, Bendelhoum Mohammed Sofiane, Abderraouf Elarbi, Lahcene Mohamed

Journal of Telecommunications and Information Technology

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2024

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nr 2

58--65

EN

Over the past decade, personal communications have witnessed exponential growth, fueled by the increasing number of connected users and the diversity of transmitted data types. This expansion necessitates a boost in the transmission systems' capacity to accommodate higher user numbers and data rates, simultaneously striving to optimize cost and complexity. Consequently, future communication systems are pivoting towards multi-carrier spread spectrum techniques (MC-CDMA), capitalizing on the robustness of OFDM multi-carrier transmissions against multipath propagation and leveraging the flexibility of the code division multiple access (CDMA) technique. \\This study addresses data transmission quality-related concerns within an MC-CDMA system by implementing UTTCM error correction codes. These codes aim to enhance channel spectrum efficiency and mitigate error probability. Simulation results demonstrate that the proposed transmission scheme offers significant improvements in terms of bit error rate and signal-to-noise ratio, while maximizing the bandwidth shared among users. Additionally, the incorporation of such equalization techniques as zero forcing (ZF) and minimum mean square error (MMSE), ensures extensive compensation for the channel selectivity effect

2

Barriers to the implementation of innovations in information systems in SMEs

Kapler Monika

Production Engineering Archives

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2021

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Vol. 27, Iss. 2

156--162

EN

Information management and information flow is an important element in the strategy of developing and running a company. The need to supervise information makes it necessary to implement numerous innovations that improve the method of information management correlated with the proper reception, selection and analysis - in both external and internal information flow. This paper presents the results of research that allowed for the assessment of barriers that arise during the implementation of innovative solutions in small and medium-sized enterprises (service MSEs). On the basis of the conducted research, it was found that the mental barrier is not always crucial from the point of view of modern technologies implementation. And the determination to implement information management innovations may be forced by the necessity of the document exchange acceleration . The success of innovative solutions e.g. in the financial services industry (in SMEs) is closely related to the technological capabilities of the enterprise - the technological barrier is crucial in this type of enterprises. Especially, taking into account the assumption that employees are highly motivated to implement new products.

3

Modified Block Sparse Bayesian Learning-Based Compressive Sensing Scheme For EEG Signals

Upadhyaya Vivek, Salim Mohammad

International Journal of Electronics and Telecommunications

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2021

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Vol. 67, No. 3

331--336

EN

Advancement in medical technology creates some issues related to data transmission as well as storage. In real-time processing, it is too tedious to limit the flow of data as it may reduce the meaningful information too. So, an efficient technique is required to compress the data. This problem arises in Magnetic Resonance Imaging (MRI), Electrocardiogram (ECG), Electroencephalogram (EEG), and other medical signal processing domains. In this paper, we demonstrate Block Sparse Bayesian Learning (BSBL) based compressive sensing technique on an Electroencephalogram (EEG) signal. The efficiency of the algorithm is described using the Mean Square Error (MSE) and Structural Similarity Index Measure (SSIM) value. Apart from this analysis we also use different combinations of sensing matrices too, to demonstrate the effect of sensing matrices on MSE and SSIM value. And here we got that the exponential and chi-square random matrices as a sensing matrix are showing a significant change in the value of MSE and SSIM. So, in real-time body sensor networks, this scheme will contribute a significant reduction in power requirement due to its data compression ability as well as it will reduce the cost and the size of the device used for real-time monitoring.

4

Complexity analyses of Godavari and Krishna river streamflow using the concept of entropy

Singh Rahul Kumar, Jain Manoj Kumar

Acta Geophysica

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2021

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Vol. 69, no. 6

2325--2338

EN

The hydrological regime in both the Godavari and Krishna River has been altered due to both human-induced and environmental changes. The present study utilizes the sample entropy and its more generalized approach known as multiscale entropy to investigate the temporal and spatial distribution of complexity and quantify them using SampEn values. Daily streamflow for five stations, three from Godavari River (Dhalegaon, Nowrangpur, and Polavaram), and two from Krishna River (Yadgir and K. Agraharam), was analysed for the complexity analyses. Trends in the streamflow for the selected gauging stations and their annual entropy values have also been evaluated using the Mann–Kendall test. The trend results revealed that three (Dhalegaon and Nowrangpur in Godavari basin and Yadgir in Krishna basin) out of five stations showed significant decreasing trends for both monthly and annual streamflow series. The declining trend in streamflow could be attributed to both anthropogenic (reservoir operation, increased water abstraction, etc.) and climatic (change in monsoon rainfall, temperature, etc.) factors. The most significant reduction in annual streamflow during the post-impact period was observed at Dhalegaon station in Godavari Basin (from 53,573 to 19,555 m3/s) signifying maximum alteration in annual flow regime. The entropy analysis results of streamflow showed that there was obvious spatial and temporal variation in the complexity, as indicated by the annual SampEn values. Although not profound, a negative correlation exists between the annual runoff and SampEn values (highest −0.42 at K. Agraharam) and hence a reverse correspondence exists between them. In MSE analysis, the original streamflow series increased with time scale (up to 30 days was chosen for this study), whereas entropy decreased with an increased time scale. Due to the fully operational state of the dams upstream of the gauging stations, the entropy values during the post-impact period were less the pre-impact period. The present study can be used as a scientific reference to use information science to detect hydrologic alterations in the river basins. Future studies should focus on considering both climatic and land-use changes in conjunction with the human-induced changes for more comprehensive river system disorder analysis.

5

Wpływ wyboru kryterium błędu filtracji na ocenę działania filtrów wygładzających

Pęksiński J., Mikołajczak G., Kowalski J.

Poznan University of Technology Academic Journals. Electrical Engineering

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2017

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No. 91

63--70

PL

W pracy porównano dwa kryteria oceny jakości przetwarzania sygnałów: błąd średniokwadratowy MSE i średni błąd absolutny MAE pod zgodności ocen. Porównania dokonano w oparciu o ważony filtr średniej ruchomej, który zaliczamy do filtrów wygładzających.

EN

The study compared two different criteria for assessing the quality of signal processing: mean square error MSE and the mean absolute error MAE for compliance assessments, The comparison was based on the weighted moving average filter, which we include the of smoothing filters.

6

Comparative Analysis of Channel Estimation Techniques in SISO, MISO and MIMO Systems

Obinna O., Kennedy O., Osemwegie O., Nsikan N.

International Journal of Electronics and Telecommunications

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2017

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Vol. 63, No. 3

299--304

EN

The ever-growing need for high data rate, bandwidth efficiency, reliability, less complexity and less power consumption in our communication systems is on the increase. Modern techniques have to be developed and put in place to meet these requirements. Research has shown, that compared to conventional Single Input Single Output (SISO) systems, Multiple-Input Single Output (MISO), and Multiple-Input Multiple-Output (MIMO) can actually increase the data rate of a communication system, without actually requiring more transmit power or bandwidth. This paper aims at the investigation of the existing channel estimation techniques. Based on the pilot arrangement, the block type and comb type are compared, employing the Least Square estimation (L.S) and Minimum Mean Squared Error (MMSE) estimators. Pilots occupy bandwidth, minimizing the number of pilots used to estimate the channel, in order to allow for more bandwidth utilization for data transmission, without compromising the accuracy of the estimates is taken into consideration. Various channel interpolation techniques and pilot-data insertion ratio are investigated, simulated and compared, to determine the best performance technique with less complexity and minimum power consumption. As performance measures, the Mean Squared Error (MSE) and Bit Error Rate (BER) as a function of Signal to Noise power Ratio (SNR) of the different channel estimation techniques are plotted, in order to identify the technique with the most optimal performance. The complexity and energy efficiency of the techniques are also investigated. The system modelling and simulations are carried out using Matlab simulation package. The MIMO gives the optimum performance, followed by the MISO and SISO. This is as a result of the diversity and multiplexing gain experienced in the multiple antenna techniques using the STBC.

7

AERSCIEA : An Efficient and Robust Satellite Color Image Enhancement Approach

Bora Dibya Jyoti

Annals of Computer Science and Information Systems

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2017

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Vol. 10

3--13

EN

Image enhancement is an important preprocessing step in any image analysis process. It helps to catalyze the further image analysis process like Image segmentation. In this paper, an approach for satellite color image enhancement on HSV color space is introduced. Here, local contrast management is given main focus because noises exist on local regions are found over amplified when enhancement is done through global enhancement technique like histogram equalization. The color arrangement and computations are done in HSV color space. The V-channel has been extracted for the enhancement process as this is the channel which represents the intensity and thereby represents the luminance of an image. At first, the image is normalized to stabilize the pixel distribution. The normalized image channel is analyzed with Binary Search Based CLAHE (BSB-CLAHE) for local contrast enhancement. The results obtained from the experiments prove the superiority of the proposed approach.

8

Efficient classes of ratio-cum-product estimators of population mean in stratified random sampling

Vishwakarma G. K., Kumar M.

Probability and Mathematical Statistics

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2016

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Vol. 36, Fasc. 2

267--278

EN

In this paper, classes of separate and combined ratio-product estimators are proposed for estimating the finite population mean in stratified random sampling. The expressions for biases and mean squared errors (MSEs) of the proposed classes are derived to the first order of approximation. It is also verified that the proposed classes of estimators, under their optimum conditions, are equivalent to the separate regression estimator. The proposed classes of estimators are compared with the other existing estimators by using the MSE criterion, and the conditions under which the proposed classes perform better are obtained. Theoretical results are validated with the help of an empirical study.

9

Drillability and Mechanical Specific Energy analysis on the example of drilling in the Pomeranian Basin

Wiśniowski R., Knez D., Hytroś Ł.

AGH Drilling, Oil, Gas

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2015

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Vol. 32, no. 1

201--210

EN

The advancements in drilling have always depended on the cost of drilling of new wellbores, therefore mathematical models of the drilling process were elaborated to minimize the cost. The first simple models based on a few fundamental parameters, were then developed into complex, computer-based models employing many variables. Models made for cutter bits are used for PDC tools. They contain formulae accounting for drilling parameters and wearing of the bit. The paper addresses works which prove that in some particular situations the influence of the tools wear on the drop of rate of penetration can be neglected, thanks to which simple formulae are obtained, based on the fundamental parameters and which are easily applicable in the field conditions. The MSE is an amount of energy used for drilling a given volume of rock. This approach is useful and practicable because allows for detecting possible inefficiencies in a relatively short time (as compared to other parameters). Attempts are made to compare the drillability indications ZSP with MSE plots, thanks to which new conclusions and observations can be drawn as far as the analysis and interpretation of drillability plots is concerned.

10

Dimensionality reduction of dynamic mesh animations using HO-SVD

Romaszewski M., Gawron P., Opozda S.

Journal of Artificial Intelligence and Soft Computing Research

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2013

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Vol. 3, No. 4

277--289

EN

This work presents an analysis of Higher Order Singular Value Decomposition (HOSVD) applied to reduction of dimensionality of 3D mesh animations. Compression error is measured using three metrics (MSE, Hausdorff, MSDM). Results are compared with a method based on Principal Component Analysis (PCA) and presented on a set of animations with typical mesh deformations.

11

An experimental comparison of popular estimation methods for the Weibull, gamma and Gompertz distributions

Żerda I.

Schedae Informaticae

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2011

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Vol. 20

67-82

EN

The aim of this study was to describe some parametric estimation methods for the Weibull, gamma and Gompertz distributions and to identify among them estimators the most efficient in practical applications. Techniques which are considered as traditional methods, like the maximum likelihood (MLE) and the method of moments (MM) estimation but also some newer and less commonly used techniques like the Lmoment estimator (LME), least-square estimator (LSE), generalized spacing estimator (GSE) and percentile estimator (PE) were presented. The application of each method was demonstrated in a simulation study using data sets generated for different distribution parameters and sample sizes. Discussed estimators were compared in terms of their efficiency and bias measured by mean-square errors (MSE) based on the simulations results.

12

Weighted smoothing filters based on fuzzy logic

Pęksiński J., Mikołajczak G.

Poznan University of Technology Academic Journals. Electrical Engineering

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2010

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No. 63

17-23

EN

The paper presents two-dimensional non-linear weighted average filter, for which weights were selected using fuzzy logic. The proposed algorithm was tested using test images in 256 shades of grey, jammed using white noise characterised by normal distribution. The mean square error (MSE) measure was used as a criterion for filtration quality assessment. The PIF coefficient was employed to assess filter impact on image structure.

13

Voice control of visual supervision system based on spectral analysis using mean square error measure

Pęksiński J., Mikołajczak G.

Poznan University of Technology Academic Journals. Electrical Engineering

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2010

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No. 63

89-94

EN

The authors presented in the study human voice recognition algorithm, which functioning is based on analysis of spectrograms with MSE (mean square error) quality measure utilization, which is employed for digital images comparing. The algorithm of human voice recognition proposed in the article was practically used for voice control of visual supervision system.

14

Absorption loss influence on optical characteristics of multilayer distributed Bragg reflector : wavelength-scale analysis by the method of single expression

Baghdasaryan H. V., Knyazyan T. M., Baghdasaryan T. H., Witzigmann B., Roemer F.

Opto-Electronics Review

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2010

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Vol. 18, No. 4

438-445

EN

Electrodynamical model of a classical distributed Bragg reflector (DBR) consisting of alternating quarter-wave layers of high and low permittivity is considered at the plane wave normal incidence. Reflective characteristics of DBR possessing absorption loss in constituting layers are analysed via correct wavelength-scale boundary problem solution by the method of single expression (MSE). Analysis of optical field and power flow density distributions within the lossy DBR structures explained the peculiarities of their reflective characteristics. Optimal configurations of lossless and lossy DBRs are revealed. Specific DBR structures possessing full transparency at definite number of layers are also analysed.