scholarly journals A review on link adaptation techniques for energy efficiency and QoS in IEEE802.11 WLAN

2020 ◽  
Vol 17 (1) ◽  
pp. 331
Author(s):  
Aliya Syahira Mohd Anuar ◽  
Wan Norsyafizan W Muhamad ◽  
Darmawaty Mohd Ali ◽  
Suzi Seroja Sarnin ◽  
Norfishah Ab Wahab
Keyword(s):  
Energy Efficiency ◽  
Signal To Noise Ratio ◽  
Radio Channel ◽  
Relevant Literature ◽  
Rate Adaptation ◽  
Link Adaptation ◽  
High Energy ◽  
Wireless Devices ◽  
Qos Performance

<span>Link adaptation is a technique that able to adapt modulation and coding scheme (MCS) based on radio channel conditions. With the exponential increase on the wireless devices nowadays, it contributes to high energy consumption and an increase in carbon dioxide (CO<sub>2</sub>) emission which contribute to the environmental issue. Researchers have developed proposals to tackle these issues by design algorithms based on link adaptation technique. Nowadays, various link adaptation techniques have been proposed by researchers with target for either Quality of Service (QoS) enhancement as well as energy efficiency. This paper presents A Review on Link Adaptation Techniques for Energy Efficiency and QoS in IEEE802.11 WLAN. In this study, a comprehensive review of the relevant literature published that focus on link adaptation technique in IEEE 802.11 WLAN in improving the energy efficiency and maximize the QoS performance is presented. Link adaptation can be categorized into transmission power control adaptation, transmission data rate adaptation and joint rate adaptation. These adaptations are carried out according to the channel state information (CSI). CSI can be categorized into signal-to-noise ratio (SNR), bit error rate (BER), delay, and queue length.</span>

scholarly journals ENERGY EFFICIENT DRYING OF SEEDS OF CEREAL CROPS

2020 ◽  
pp. 64-70
Author(s):  
Vadym Paziuk
Keyword(s):  
Energy Efficiency ◽  
Low Temperatures ◽  
Energy Efficient ◽  
High Energy ◽  
Biochemical Properties ◽  
Drying Process ◽  
Seed Material ◽  
Technical Solutions ◽  
Low Temperature Drying

Many researchers at different times have been engaged in drying cereals to preserve their nutritional properties, which is associated with the biochemical properties of materials. The technologies for drying grain crops have been developed and improved with the given recommendations aimed at carrying out the drying process at high temperatures (above 100 ° C). But the increased requirements for seed grains and the associated high energy costs do not allow the drying process to be carried out efficiently, since with large grain volumes this leads to a significant increase in material costs. The study of the laws of drying of seeds of cereals in view of improving the energy efficiency of the process is relevant. Energy efficiency is one of the main parameters influencing the choice of drying mode. In traditional technologies for drying seed material, it is dried at low temperatures, which does not allow to significantly intensify the process by increasing the temperature of the coolant, as this significantly reduces the quality of the material. The state of the art makes it possible to more accurately investigate and analyze the drying processes of cereal seeds with automatic processing and plotting of drying kinetics. The results of previous researchers were conducted on existing grain dryers, in which it is difficult to evaluate and give the correct recommendations for drying the seed material. This is due to the peculiarities of the drying process and the design of the grain dryer. To adequately assess the drying regimes, studies of drying seeds of cereals at low temperatures were carried out to preserve the seed properties of the material. To increase the energy efficiency of the drying process, a step-by-step descending low-temperature drying mode is proposed, which provides the required quality of seed material. All the proposed technical solutions for the introduction of energy-efficient regimes in the process of drying grain seeds were implemented in the recommendations for industrial drying in mine direct-flow grain dryers.

scholarly journals Spectral Efficiency Evaluation of 5G Waveform Candidates

2019 ◽  
Vol 8 (2S8) ◽  
pp. 1779-1781
Keyword(s):  
Energy Efficiency ◽  
Performance Evaluation ◽  
Spectral Efficiency ◽  
High Energy ◽  
Efficiency Evaluation ◽  
Fifth Generation ◽  
High Energy Efficiency ◽  
And Performance ◽  
Wireless Standards

To increase the performance and to meet quality of service (QoS) requirements of future wireless communication and networks, some of these approaches compete for incorporation in future wireless standards such as fifth generation (5G). In this paper comparative study and performance evaluation in terms of spectral efficiency (SE) their PAPR of different 5G waveform candidates. Most multicarrier schemes suffer from high PAPR and are not suitable when high energy efficiency is required

scholarly journals Heat Recovery Ventilation Systems and their Physical Quantification

2021 ◽  
Vol 1203 (2) ◽  
pp. 022045
Author(s):  
Boris Bielek ◽  
Daniel Szabó ◽  
Josip Klem ◽  
Roman Grolmus
Keyword(s):  
Energy Efficiency ◽  
Heat Recovery ◽  
Ventilation System ◽  
Co2 Concentration ◽  
High Energy ◽  
Operating Conditions ◽  
Indoor Climate ◽  
Measurement Results ◽  
Ventilation Systems

Abstract The essence of ventilation is the exchange of air in the room for fresh outside air. At the same time ventilation is a factor that can significantly affect the energy efficiency of a building. Hygienic requirements for ventilation of interiors of buildings in the context of increasing the energy efficiency of buildings lead to the transformation of unregulated ventilation by infiltration to regulated ventilation systems with heat recovery. The regulated ventilation system makes it possible to optimize the ventilation intensity on the basis of a stimulus from the room user or automatically on the basis of sensors monitoring the quality of the indoor climate (temperature and relative humidity, CO2 concentration in the air, etc.). In addition, if we use a ventilation system with heat recovery from the exhaust air to preheat the fresh supply air to the room, we can achieve high energy efficiency of the building by meeting the hygienic criteria of the indoor climate. The article describes heat recovery ventilation systems and their basic conceptual solutions applied in the modern architecture. The heat exchange between the hot exhaust air and the cold supply air in the winter takes place in heat recovery ventilation units in the heat exchanger. The efficiency of heat recovery defines how much heat we can transfer from the exhaust air to the fresh air in the heat recovery exchanger. The article analyses individual factors influencing the efficiency of heat recovery. Due to the fact that the manufacturers of heat recovery ventilation units declare in their brochures or websites the values of the maximum efficiencies of their products, we were interested in their real efficiencies under normal operating conditions. Therefore, we subjected to experimental research in a large climate chamber a product from the German manufacturer Lunos, namely a specific type of decentralized heat recovery unit Lunos Nexxt E. The article describes the methodology of laboratory experiment, used experimental basis, brings and analyses measurement results and calculates real efficiency of the subject heat recovery in accordance with STN EN 13 141. In the end it compares measured values with the values from the manufacturer.

Towards Layer Adaptation for Audio Transmission

2014 ◽  
Vol 6 (4) ◽  
pp. 35-41
Author(s):  
Jan Holub ◽  
Oldřich Slavata ◽  
Pavel Souček ◽  
Odysseas Zisimopoulos ◽  
Dimitris Toumpakaris ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Rate Adaptation ◽  
Physical Layer ◽  
Wireless Channel ◽  
Audio Quality ◽  
Opinion Score ◽  
Constant Rate ◽  
Channel Conditions ◽  
Channel Errors

When audio is transmitted over the wireless channel, the quality of the audio depends on the signal-to-noise ratio (SNR). The purpose of this paper is to investigate if rate adaptation can be avoided, and a system can rely instead on the audio encoder and decoder to alleviate the effect of channel errors. To this end, the paper reports on a set of experiments on various combinations of channel conditions, constellation sizes and audio encoding used and on the final audio quality achieved. The Mean Opinion Score (MOS) is used for performance evaluation. The MOS values are generated using the ITU-T P.862 (PESQ) and P.863 (POLQA) algorithms, and also using tests by experts. The results support the common practice of adapting the physical layer parameters to changing channel conditions. However, in some cases, it is possible to maintain a constant rate without impacting significantly the quality of the audio. This means that the complexity associated with physical layer and audio rate adaptation can be avoided leading to simpler and more robust designs.

Pre-Processing of Hyperspectral Images Using Nonlinear Filters

2013 ◽  
Vol 11 (1) ◽  
pp. 8-13
Author(s):  
V. Behar ◽  
V. Bogdanova
Keyword(s):  
Signal To Noise Ratio ◽  
Correlation Coefficients ◽  
Hyperspectral Images ◽  
Spectral Correlation ◽  
Edge Preserving ◽  
Improvement Factor ◽  
Filter Output ◽  
Average Improvement ◽  
Processing Procedure

Abstract In this paper the use of a set of nonlinear edge-preserving filters is proposed as a pre-processing stage with the purpose to improve the quality of hyperspectral images before object detection. The capability of each nonlinear filter to improve images, corrupted by spatially and spectrally correlated Gaussian noise, is evaluated in terms of the average Improvement factor in the Peak Signal to Noise Ratio (IPSNR), estimated at the filter output. The simulation results demonstrate that this pre-processing procedure is efficient only in case the spatial and spectral correlation coefficients of noise do not exceed the value of 0.6

Image Quality Enhancing by Efficient Histogram Equalization

2014 ◽  
Vol 2 (2) ◽  
pp. 47-58
Author(s):  
Ismail Sh. Baqer
Keyword(s):  
Image Quality ◽  
Contrast Enhancement ◽  
Mean Squared Error ◽  
Signal To Noise Ratio ◽  
Histogram Equalization ◽  
Gray Level ◽  
Signal To Noise ◽  
Squared Error ◽  
Noise Ratio

A two Level Image Quality enhancement is proposed in this paper. In the first level, Dualistic Sub-Image Histogram Equalization DSIHE method decomposes the original image into two sub-images based on median of original images. The second level deals with spikes shaped noise that may appear in the image after processing. We presents three methods of image enhancement GHE, LHE and proposed DSIHE that improve the visual quality of images. A comparative calculations is being carried out on above mentioned techniques to examine objective and subjective image quality parameters e.g. Peak Signal-to-Noise Ratio PSNR values, entropy H and mean squared error MSE to measure the quality of gray scale enhanced images. For handling gray-level images, convenient Histogram Equalization methods e.g. GHE and LHE tend to change the mean brightness of an image to middle level of the gray-level range limiting their appropriateness for contrast enhancement in consumer electronics such as TV monitors. The DSIHE methods seem to overcome this disadvantage as they tend to preserve both, the brightness and contrast enhancement. Experimental results show that the proposed technique gives better results in terms of Discrete Entropy, Signal to Noise ratio and Mean Squared Error values than the Global and Local histogram-based equalization methods

Reactions in Activated Peroxide Systems and their Influences on Bleaching Performance

2020 ◽  
Vol 17 ◽  
Author(s):  
Xiaoyan Wang ◽  
Jinmei Du ◽  
Changhai Xu
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Energy Efficiency ◽  
Textile Industry ◽  
High Energy ◽  
Side Reactions ◽  
Competitive Reactions ◽  
High Energy Efficiency ◽  
Hydrolysis Of ◽  
Bleach Activators

Abstract:: Activated peroxide systems are formed by adding so-called bleach activators to aqueous solution of hydrogen peroxide, developed in the seventies of the last century for use in domestic laundry for their high energy efficiency and introduced at the beginning of the 21st century to the textile industry as an approach toward overcoming the extensive energy consumption in bleaching. In activated peroxide systems, bleach activators undergo perhydrolysis to generate more kinetically active peracids that enable bleaching under milder conditions while hydrolysis of bleach activators and decomposition of peracids may occur as side reactions to weaken the bleaching efficiency. This mini-review aims to summarize these competitive reactions in activated peroxide systems and their influence on bleaching performance.

Singular Values Decomposition and Lifting Wavelet Transform for Speech Signal Embedding into Digital Image

2019 ◽  
Vol 12 (2) ◽  
pp. 138-151
Author(s):  
Mourad Talbi ◽  
Med Salim Bouhlel
Keyword(s):  
Wavelet Transform ◽  
Speech Signal ◽  
Signal To Noise Ratio ◽  
Perceptual Quality ◽  
Lifting Wavelet Transform ◽  
Signal To Noise ◽  
Perceptual Evaluation ◽  
Lifting Wavelet ◽  
Noise Ratio

Background: In this paper, we propose a secure image watermarking technique which is applied to grayscale and color images. It consists in applying the SVD (Singular Value Decomposition) in the Lifting Wavelet Transform domain for embedding a speech image (the watermark) into the host image. Methods: It also uses signature in the embedding and extraction steps. Its performance is justified by the computation of PSNR (Pick Signal to Noise Ratio), SSIM (Structural Similarity), SNR (Signal to Noise Ratio), SegSNR (Segmental SNR) and PESQ (Perceptual Evaluation Speech Quality). Results: The PSNR and SSIM are used for evaluating the perceptual quality of the watermarked image compared to the original image. The SNR, SegSNR and PESQ are used for evaluating the perceptual quality of the reconstructed or extracted speech signal compared to the original speech signal. Conclusion: The Results obtained from computation of PSNR, SSIM, SNR, SegSNR and PESQ show the performance of the proposed technique.

scholarly journals 3D DCT Based Image Compression Method for the Medical Endoscopic Application

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1817
Author(s):  
Jiawen Xue ◽  
Li Yin ◽  
Zehua Lan ◽  
Mingzhu Long ◽  
Guolin Li ◽  
...  
Keyword(s):  
Image Compression ◽  
Compression Ratio ◽  
Signal To Noise Ratio ◽  
Blocking Artifacts ◽  
Compression Method ◽  
High Compression Ratio ◽  
Multiplication Operation ◽  
3D Data ◽  
Wireless Capsule

This paper proposes a novel 3D discrete cosine transform (DCT) based image compression method for medical endoscopic applications. Due to the high correlation among color components of wireless capsule endoscopy (WCE) images, the original 2D Bayer data pattern is reconstructed into a new 3D data pattern, and 3D DCT is adopted to compress the 3D data for high compression ratio and high quality. For the low computational complexity of 3D-DCT, an optimized 4-point DCT butterfly structure without multiplication operation is proposed. Due to the unique characteristics of the 3D data pattern, the quantization and zigzag scan are ameliorated. To further improve the visual quality of decompressed images, a frequency-domain filter is proposed to eliminate the blocking artifacts adaptively. Experiments show that our method attains an average compression ratio (CR) of 22.94:1 with the peak signal to noise ratio (PSNR) of 40.73 dB, which outperforms state-of-the-art methods.

Sign in / Sign up

Export Citation Format

Share Document