Compression Ratio

Waste management and mitigation is the primary necessity across the globe. The daily use of plastic materials in different forms emergence the plastic pollutions, and it has been significantly increased during the COVID-19 pandemic. Thus, mitigation of waste plastics generation is one of the major challenges in the present situation. The present study addressed the conversion of waste plastics into value-added products such as liquid hydrocarbon fuels and their application in reducing greenhouse gas emissions. A comprehensive investigation has been performed on engine performance and combustion characteristics at various compression ratios and PO blending. The effect of liquid fuel blending with commercial diesel was investigated at three different compression ratios (15.1, 16.2, and 16.7) under various BMEP conditions. The results revealed that blending of liquid fuel produced from waste plastic can improve the BTE significantly, and the highest 35.77% of BTE was observed for 10% blending at 15.1 CR. While the lowest BSFC of 5.77 × 10 -5 kg/kW-s was estimated for 20% PO blending at 16.7 CR under optimum BMEP (4.0 bar) conditions. The investigation of combustion parameters such as cylinder pressure, net heat release rate, rate of pressure rise, and cumulative heat release showed that it increases with the compression ratio from 15.1 to 16.7. At the same time, the emissions of CO, CO 2 , and unburnt hydrocarbon was decreased significantly. The economic analysis for the present lab-scale study estimated that approximately ₹12.17 ($0.15) profit per liter is possible in the 1st year, while the significant profit starts from the 2nd year onward, which is in the range of ₹59.78-₹84.48 ($0.75-$1.07) when the PO is blended with CD within the permissible limits as per the norms.

Image compression is essential for applications such as transmission and storage of databases. Artificial and Natural images are inherently voluminous. Therefore, efficient data compression techniques are essential for their archival and transmission of data. The standards use Discrete Cosine Transform (DCT) to reduce the spatial redundancy present in the images or video frames. The DCT has the main drawback of blocking artifacts. In recent time, wavelet transform (WT) has emerged as a popular technique for image compression applications. The wavelet transform has high de-correlation and energy compaction efficiency. The blocking artifacts is absent in a wavelet-based coder due to their overlapping basis functions. The wavelet transform can be composed of any function that satisfies requirements of multi-resolution analysis. In waveletbased image compression, the compression performance depends on the choice of wavelets. A review of the wavelet family used for compression is given i...

We present a detailed study of an asymmetrically driven quantum Otto engine with a timedependent harmonic oscillator as its working medium. We obtain analytic expressions for the upper bounds on the efficiency of the engine for two different driving schemes having asymmetry in the expansion and compression work strokes. We show that the Otto cycle under consideration cannot operate as a heat engine in the low-temperature regime. Then, we show that the friction in the expansion stroke is significantly more detrimental to the performance of the engine as compared to the friction in the compression stroke. Further, by comparing the performance of the engine with sudden expansion, sudden compression, and both sudden strokes, we uncover a pattern of connections between the operational points, and we indicate the optimal operation regime for each case. Finally, we analytically characterize the complete phase diagram of the Otto cycle for both driving schemes and highlight the different operational modes of the cycle as a heat engine, refrigerator, accelerator, and heater.

The growing need for cooling, combined with the environmental concerns surrounding conventional mechanical vapour compression (MVC) systems, has accelerated research for sustainable cooling solutions driven by low-grade heat. Single-stage dual-bed adsorption chillers (ADCs) using silica gel and water provide a promising approach due to their continuous cooling output, lower complexity, and the use of environmentally safe working fluids. However, limitations in their performance, specifically in the coefficient of performance (COP), cooling capacity (Q cc ), and waste heat recovery efficiency (η e ), necessitate improvement through optimization. This study employs statistically validated regressionbased objective functions to optimize ten decision variables using the single Grey Wolf Optimizer (GWO) and its multi-objective variant, Muilti-Objective Grey Wolf Optimization (MOGWO), for a silica gel-water single-stage dual-bed ADC. The results from the single-objective optimization showed a maximum coefficient of performance (COP) of 0.697, cooling capacity (Q cc ) of 20.76 kW, and waste heat recovery efficiency (ηe) of 0.125. The values from the Pareto-optimal solutions for the MOGWO ranged from 0.5123 to 0.6859 for COP, 12.45 to 20.73 kW for Q cc and 8.24% to 12.48% for η e , demonstrating superior performance compared to existing benchmarks. A one-at-a-time sensitivity analysis revealed non-linear and non-monotonic impacts of variables, confirming the robustness and physical realism of the MOGWO model. The developed MOGWO framework effectively enhances the performance of the single-stage dual-bed ADC and improves low-grade heat utilization, offering a robust decision-support tool for system design and optimization.

In order to utilize a raw biogas as a fuel of generator set (gen-set), it is important to figure out optimum operating parameter of the gen-set, i.e. compression ratio. The present work aims to investigate the effect of compression ratio on performance of 3 kW gen-set fuelled with raw biogas and to obtain optimum compression ratio for operation of the gen-set on raw biogas. The gen-set used in the present work is bi-fuel engine, i.e. fuelled with gasoline or LPG. The performance of the engine fuelled with raw biogas in terms of brake power, brake torque, brake specific fuel consumption, and thermal efficiency is evaluated at compression ratio of 7.5, 8.5, 9.5, and 10.5. The work is carried out under electrical load of 240, 420, and 600 Watt. The result indicates that compression ratio affects the rotational speed, brake power, brake torque, brake specific fuel consumption, and thermal efficiency of the gen-set. Optimum compression ratio for the gen-set fuelled with raw biogas is 9.5...

The need for alternative source of energy with little to no harmful effect and has economic advantage over the current sources has led to intensified efforts in harnessing natural resources to produce renewable energy. The current work characterized biodiesel produced from groundnut oil by transesterification. The moisture content, ash content, density, viscosity of the biodiesel produced were assessed. The FTIR spectroscopy of the feedstock and the product were also determined. Results from this work showed an ester yield of 62.5%, which is a little lower than that obtained by some researchers. The moisture content was shown to be 3.45%, the ash content was 0.2%, and the density was found to be 0.76 g /cm3. The viscosity was found to be 488.21 mm 2 /s at 27.3 o C. Trans-esterification method is found to be good in producing biodiesel from groundnut as corroborated by several investigations. Due to high viscosity of the biodiesel produced, it is recommended that the product should be used in blend with fossil diesel and NMR can be used for further characterization.

Fractal Image Compression is a lossy compression method for images based on fractals rather than pixels, which are best suited for texture and natural images. It works on self similarity property, relying on the fact that parts of an image often resemble other parts of the same image. It takes long encoding time and affects the image quality. This paper introduces an improved quantized quad tree technique for fractal image compression. Quantized quad tree method divides the original gray level image into various blocks depending on features presented in image. Simulation results show that with the quantized quad trees compression improves the compression ratio and PSNR without losing the quality of the image compression with range block, domain block and iterations technique.

for medical image and biomedical signal compression in the last decades. The performance of CS based compression is mostly dependent on decoding methods rather than the CS encoding methods used in practice. Many CS encoding and decoding algorithms have been reported in literature. However, the comparative study on performance metrics of CS encoding with block processing and without block processing is not investigated by the researchers so far. This paper proposes block CS based medical images and signals compression technique and the proposed technique is compared with standard CS compression. The proposed algorithm divides the input medical images and signals to blocks and each block is processed parallel to enable faster computation. Three performance indices, i.e., the peak signal to noise ratio (PSNR), reconstruction time (RT) and structural similarity index (SSIM) were tested to observe their changes with respect to compression ratio. The results showed that block CS algorithm had better performance than standard CS based compression. More specifically, the parallel block CS reported the best results than standard CS with respect to less reconstruction time and satisfactory PSNR and SSIM.

In this paper, a hybrid data compression scheme based on predictive compressed sensing (CS) and light weight lossless compression is suggested for wireless sensor networks (WSNs). CS based techniques are well motivated in WSNs not only for sparse signals but also by the requirement of efficient in-network processing in terms of transmit power and communication bandwidth even with nonsparse signals. This algorithm exploits prediction-based approach in which the difference between the actual measurements and the predicted measurements of the dataset is encoded using CS technique with reasonable error. The CS encoded data is further compressed using Huffman encoding to improve the compression ratio without any loss in quality. We analyzed the performance, data rate saving and inaccuracy introduced by the hybrid compression algorithm. The post processing analysis shows high compression ratios, with acceptable mean squared error.

for medical image and biomedical signal compression in the last decades. The performance of CS based compression is mostly dependent on decoding methods rather than the CS encoding methods used in practice. Many CS encoding and decoding algorithms have been reported in literature. However, the comparative study on performance metrics of CS encoding with block processing and without block processing is not investigated by the researchers so far. This paper proposes block CS based medical images and signals compression technique and the proposed technique is compared with standard CS compression. The proposed algorithm divides the input medical images and signals to blocks and each block is processed parallel to enable faster computation. Three performance indices, i.e., the peak signal to noise ratio (PSNR), reconstruction time (RT) and structural similarity index (SSIM) were tested to observe their changes with respect to compression ratio. The results showed that block CS algorithm had better performance than standard CS based compression. More specifically, the parallel block CS reported the best results than standard CS with respect to less reconstruction time and satisfactory PSNR and SSIM.

The research and development of hydrogen-internal combustion engine (ICE) system for heavy-duty trucks, with the goal of allowing carbon dioxide (CO 2 )-free operation in transportation department, has been carried out. The high-pressure hydrogen gas direct-injector was adapted to the single-cylinder ICE. The high-pressure direct-injection combustion system shows that high thermal efficiency, high specific output and low NOx emission were confirmed. From these results, it is concluded that the possibility of the application from those results to a multi-cylinder hydrogen-ICE is high. The NOx storage reduction (NSR) catalyst system was applied as the after-treatment device of the exhaust NOx emission from hydrogen-ICE and it was confirmed that very low effect to fuel consumption and high reduction effect of NOx emission were feasible experimentally.

We show that the problem of constructing a perfect matching in a graph is in the complexity class Random NC; i.e., the problem is solvable in polylog time by a randomized parallel algorithm using a polynomial -bounded number of processors. We also show that several related problems lie in Random NC.

This study evaluated the compressibility of multislice CT (MSCT) datasets and its dependence on (1) slice thickness and (2) the use of three-dimensional (3D) vs. 2D JPEG2000 compression methods. Five thoracic CT datasets were obtained using a 16-detector MSCT scanner with a collimation of 0.75 mm (120 kVp, 90 mAs) and reconstructed at five slice thicknesses from 0.75 to 10.0 mm. These datasets were irreversibly compressed using a standard 2D JPEG2000 encoder and a developmental 3D JPEG2000 algorithm based on Part 2 of the JPEG2000 standard. Compression ratios ranged from 4:1 to 64:1. Image distortion was computed utilizing peak signal-tonoise ratio (PSNR) and the Sarnoff JNDmetrix visual discrimination model. For 2D compression, the thinnest sections were substantially less compressible than thicker sections for the same level of image quality, particularly at higher compression ratios. Applying 3D compression yielded consistently higher image quality in most cases compared to 2D compression at the same ratios. The advantage of 3D compression increased for thinner slices and higher compression ratios. These results indicate that 3D JPEG2000 (Part 2) compression offers substantial advantages over the current 2D JPEG2000 standard, yielding better quantitative image quality at similar compression ratios or comparable image quality at higher compression ratios. D 2004 Published by Elsevier B.V.

The SPARC project foresees the realization of a high brightness photo-injector to produce a 150-200 MeV electron beam to drive 500 nm FEL experiments in various configurations, a Thomson backscattering source and a plasma accelerator experiment (these last two ones jointly with the project PLASMONX). The SPARC photoinjector is also the test facility for the recently approved VUV FEL project named SPARX. The second stage of the commissioning, that is currently underway, foresees a detailed analysis of the beam matching with the linac in order to confirm the theoretically prediction of emittance compensation based on the "invariant envelope" matching and the demonstration of the "velocity bunching" technique in the linac. SASE, SEEDING and Single Spike experiments are foreseen by the end of the current year. In this contribution we report the experimental results obtained so far and the scientific program for the near future.

Large hyper-volume visualization is required by today physic and is still a research area in scientific visualization. Espe- cially, the interactive exploration of datasets remains highly challenging as soon as the data size exceeds a certain thresh- old. We describe in this paper an hyperslicing-based inter- active visualization technique designed to explore at real- time frame rates large hyper-volumetric 4D scalar fields (i.e. datasets beyond 16GB) defined on regular structured grids. The key issue consists in coupling the visualization with a new efficient data representation scheme, in such a way that it overcomes the different steps of scientific visualiza- tion, namely simulation post-processing, visualization pre- processing and finally interactive display. By introducing a hierarchical finite element representation, we show that our technique allows users to explore the full dataset at real-time frame-rates on low-end PCs. We demonstrate the effective- ness of our technique...

Within a perturbative treatment of realistic local electron-ion pseudopotentials for the simple metals, we study structural phase transitions under pressure in Na and other monovalent metals, Mg and other divalent metals, and Al and other trivalent metals. For the "good local pseudopotential" metals Na, Mg, and Al, our results are in reasonable agreement with experiment. The sequence of predicted transitions between crystal structures, and the volume compression ratios V/V 0 at which these transitions are predicted, are determined largely by the valence z. The valence z also determines the dependence of the total energy upon the tetragonal c/a ratio along the Bain path from bcc to fcc. This path shows the divalent metals unstable in both fcc and bcc structures, and the trivalent metals unstable in bcc.

Image compression coders can be lossy or lossless. Fractal image compression is a lossy image compression technique to achieve high level of compression while preserving the quality of the decompressed image close to that of the original image. The method relies on the fact that in a certain images, parts of the image resemble other parts of the same image (self-similarity). In this paper we evaluate fractal techniques for image compression and investigate their ability to compress cDNA microarray images. Selfsimilarity is a typical property of fractals. In mathematics a self-similar object is an object that is exactly or approximately similar to a part of itself. There exists high self-similarity in cDNA microarray images. This feature makes the images vulnerable to be compressed with the fractal methods. Two implementations of fractal (Pure-fractal and Waveletfractal image compression algorithms) have been applied on the cDNA microarray images in different configurations in order to investigate the compression ratio and corresponding quality of the images using peak signal to noise ratio (PSNR). 1

The standard JPEG format is almost the optimum format in image compression. The compression ratio in JPEG sometimes reaches 30:1. The compression ratio of JPEG could be increased by embedding the Five Modulus Method (FMM) into the JPEG algorithm. The novel algorithm gives twice the time as the standard JPEG algorithm or more. The novel algorithm was called FJPEG (Five-JPEG). The quality of the reconstructed image after compression is approximately approaches the JPEG. Standard test images have been used to support and implement the suggested idea in this paper and the error metrics have been computed and compared with JPEG.

In this paper, we propose a new algorithm to make a novel spatial image transformation. The proposed approach aims to reduce the bit depth used for image storage. The basic technique for the proposed transformation is based of the modulus operator. The goal is to transform the whole image into multiples of predefined integer. The division of the whole image by that integer will guarantee that the new image surely less in size from the original image. The k-Modulus Method could not be used as a stand alone transform for image compression because of its high compression ratio. It could be used as a scheme embedded in other image processing fields especially compression. According to its high PSNR value, it could be amalgamated with other methods to facilitate the redundancy criterion.

Variable valve timing (VVT) is an advanced modern technique applied in internal combustion engines by altering the valve lift event timing. This work aims to contribute to the continuing industrial VVT development to improve engine efficiency, fuel consumption and performance. To observe the influence on the spark-ignition (SI) engine’s performance, four valve timing strategies are selected carefully by varying the intake and exhaust valve timing. Lotus Engine Simulation, a simulation engineering software, is adapted in this study. The engine characteristics used in this modelling are spark engine, multicylinder, four strokes, port injection fuel system and constant compression ratio. A comparison between a conventional standard exhaust/intake valve timing and three other different timing cases is carried out. Results reveal that the overlap case of 98° showed a good brake-specific fuel consumption by approximately 3% less than the conventional case. An improvement of 6.2% for volume efficiency and 2.9% in brake thermal efficiency is also reported.

Image inpainting refers to the task of filling in the missing or damaged regions of an image in an undetectable manner. There are a large variety of image inpainting algorithms existing in the literature. They can broadly be grouped into two categories such as Partial ...

The performance of real mixed-flow low bypass ratio turbofan jet engine in which the core stream and bypass one are mixed together before passing through an afterburner and single exhaust nozzle has been analyzed. The performance of this type of engine is determined at a range of compressor pressure ratios and bypass ratios, that best meet the design requirements for a modern jet fighter aircraft. This analysis is carried out using the advance parametric technology for the components of this jet engine. A computer program is achieved utilizing the MATALAB programming language in order to perform the required calculations. The required specific thrust at design-point supersonic cruise flight condition, that must be able to offset drag force development is computed. Variations of specific thrust and specific fuel consumption versus bypass ratios and compressor pressure ratios plots for the supersonic cruise condition are drawn illustrating the computed results. Eventually, selecting the promising engine for chosen fighter aircraft has been established.

Fossil fuel is getting exhausted at a fast rate and contributes to high carbon monoxide emissions. Biodiesel, being environmentally friendly, has better performance than diesel. Castor oil is an easily available vegetable oil in India. But its high viscosity leads to blockage of the fuel lines. The amount of free fatty acid more than 1% leads to soap formation which necessitates the biodiesel production in a two step process. The first step of acid catalyzed esterification process reduces the free fatty acid content of castor oil to below 1%. The second step of transesterification process converts the preheated oil to castor biodiesel. This two step process gave a maximum yield of 90%.The methyl castor oil (biodiesel) is blended with diesel in different proportions on volume basis as 15:85 (B15), 25:75 (B25), and 35:65 (B35). These blended oils are used to run a single cylinder four stroke compression ignition engine with different coatings of pistons, to study and compare the engin...

While computing power and transmission bandwidth have both been steadily increasing over the last few years, bandwidth rather than processing power remains the primary bottleneck for many complex multimedia applications involving communication. Current video coding algorithms use intelligent encoding to yield higher compression ratios at the cost of additional computing requirements for encoding and decoding. The use of techniques from the fields of computer vision and robotics such as object recognition, scene interpretation, and tracking can further improve compression ratios as well as provide additional information about the video sequence being transmitted. We used a new face tracking system developed in the robotics area to normalize a video sequence to centered images of the face. The face-tracking allowed us to implement a compression scheme based on Principal Component Analysis (PCA), which we call Orthonormal Basis Coding (OBC). We designed and implemented the face tracker and video codecs entirely in software. Our current implementation of OBC operates on recorded video sequences, making it appropriate for applications such as video email.

Wider dissemination of medical digital video libraries is affected by two correlated factors, resource effective content compression that directly influences its diagnostic credibility. It has been proved that it is possible to meet these contradictory requirements halfway for long-lasting and low motion surgery recordings at compression ratios close to 100 (bronchoscopic procedures were a case study investigated). As the main supporting assumption, it has been accepted that the content can be compressed as far as clinicians are not able to sense a loss of video diagnostic fidelity (a visually lossless compression).Different market codecs were inspected by means of the combined subjective and objective tests toward their usability in medical video libraries. Subjective tests involved a panel of clinicians who had to classify compressed bronchoscopic video content according to its quality under the bubble sort algorithm. For objective tests, two metrics (hybrid vector measure and hos...

Nowadays, increasingly stricter regulations on emission reduction are inducing rapid developments in combustion science. Low-temperature combustion (LTC) is an advanced combustion technology that increases an engine’s thermal efficiency and even provides low emissions of nitrogen oxides (NOx) and particulate matter (PM). The technology often uses early direct injections to achieve sufficient mixture homogeneity. This leads to increasing wall wetting and lower combustion efficiency. This paper introduces the Multipulse ballistic injection (MBI) method to improve combustion with early injection timings. The research was carried out in a four-cylinder medium-duty diesel engine with high-pressure exhaust gas recirculation (HP-EGR). The investigation was divided into two experiments. In the first experiment, MBI was examined without EGR, and in the second, EGR was applied to study its effects. It was found that the MBI strategy decreased wall wetting and increased homogeneity and the ind...

The aim of this paper is to evaluate the impact of connected autonomous behavior in real vehicles on vehicle fuel consumption and emission reductions. Authors provide a preliminary theoretical summary to assess the driving conditions of autonomous vehicles in roundabout, which attempts exploring the impact of driving behavior patterns on fuel consumption and emissions, and including other key factors of autonomous vehicles to reduce fuel consumption and emissions. After summarizing, driving behavior, effective in-vehicle systems, both roundabout physical parameters and vehicle type are all play an important role in energy using. ZalaZONE’s roundabout is selected for preliminary test scenario establishment, which lays a design foundation for further in-depth testing.

Advertising is a marketing communication message or public communication about a product that is conveyed through a medium, financed by a known initiator, and addressed to part or all of the community. PT. Amanah Wisata Travel also uses advertising promotions on its website to attract potential customers to use their services. However, the number of advertisements on the website will be burdensome for the website, because there are too many files such as images and videos, and this can take up storage space on web hosting. Data compression is one way that this problem can be resolved, because by using data compression it can minimize a file size in the form of an image or video from the ad. Large data sizes result in waste of memory and the slow process of moving or duplicating data so that it is necessary to do ways to minimize data storage. The aim of this research is to minimize the file size on the PT. Amanah Travel in the form of images. If the size of the file being transferre...

The results of the performance and emission of a variable compression ratio ignition engine (vertical single cylinder) by using Jatropha ethyl ester blends with diesel fuel at two levels of compression ratio (16.5:1 and 18.5:1) have been presented in this paper. The fuel samples were prepared by blending Jatropha ethyl ester with diesel in the composition of 0:100, 10:90, 20:80, 30:70 and 40:60 (%). Results indicated that Brake thermal efficiency for all biodiesel blends was more as compared to diesel. Brake thermal efficiency increased with the increase in load and also increased with the increase in compression ratio. Brake specific fuel consumption in case of blends was more as compared to diesel. Brake specific fuel consumption decreased with the increase in load as well as with the increase in compression ratio. Exhaust gas temperature increased with the increase in load and also increased with the increase in compression ratio for all fuel blends.

In this paper, we present an algorithm to construct an approximate convex hull of the attractors of an affine iterated function system (IFS). We construct a sequence of convex hull approximations for any required precision using the self-similarity property of the attractor in order to optimize calculations. Due to the affine properties of IFS transformations, the number of points considered in the construction is reduced. The time complexity of our algorithm is a linear function of the number of iterations and the number of points in the output convex hull. The number of iterations and the execution time increases logarithmically with increasing accuracy. In addition, we introduce a method to simplify the approximation of the convex hull without loss of accuracy.

DIT has competed for a number of years in the Formula Student competition with petrol engine propelled vehicles. Dynamometer testing on these engines was traditionally outsourced. In 2017/2018 a decision was made to commence the design of an electric vehicle. Access to a suitable dynamometer for regular testing became more important than ever in order to fully characterise the electric motors the gearbox combinations and optimise the performance of the formula student electric vehicle. This paper deals with the design and manufacture and component selection for a mobile dynamometer that can accurately simulate racetrack conditions and apply typical loading cycles to a motor producing torque, power and speed values from a typical drivetrain. The dynamometer described uses a particle brake to apply the loads, a datum M425 torque transducer to measure torque and a National Instruments LabVIEW interface to display and store data during testing. Safety is of vital importance and this paper describes the high-safety standards applied during the design and manufacture phase. With the implementation of an electronic control circuit, motor characteristics charts are produced, analysed and utilised for calibration and benchmarking for future motor test runs. Aim: Design & Manufacture of a mobile dynamometer unit to produce torque, speed and power values from the drive train of a motor.

In this paper, we analyze the performance of electrocardiogram (ECG) signal compression by comparing original and reconstructed signal on two problems. First, automatic sleep stage classification based on ECG signal; second, arrhythmia classification. An effective ECG signal compression method based on two-dimensional wavelet transform which employs set partitioning in hierarchical trees (SPIHT) and beat reordering technique used to compress the ECG signal. This method utilizes the redundancy between adjacent samples and adjacent beats. Beat reordering rearranges beat order in 2D (2 dimension) ECG array based on the similarity between adjacent beats. The experimental results show that the proposed method yields relatively low distortion at high compression rate. The experimental results also show that the accuracy of sleep stage classification and arrhythmia classification using reconstructed ECG signal from proposed method is comparable to the original signal. The proposed method p...

The frame rates and resolutions of digital videos are on the rising edge. Thereby, pushing the compression ratios of video coding standards to their limits, resulting in more complex and computational power hungry algorithms. Programmable solutions are gaining interest to keep up the pace of the evolving video coding standards, by reducing the timeto-market of upcoming video products. However, to compete with hardwired solutions, parallelism needs to be exploited on as many levels as possible. In this paper the focus will be on data level parallelism. Huffman coding is proven to be very efficient and therefore commonly applied in many coding standards. However, due to the inherently sequential nature, parallelization of the Huffman decoding is considered hard. The proposed fully flexible and programmable acceleration exploits available data level parallelism in Huffman decoding. Our implementation achieves a decoding speed of 106 MBit/s while running on a 250 MHz processor. This is a speed-up of 24× compared to our sequential reference implementation.

The rapid growth of digital imaging applications, including desktop publishing, multimedia, teleconferencing, and high definition television (HDTV) has increased the need for effective and standardized image compression techniques. Among the emerging standards are JPEG, for compression of still images; MPEG, for compression of motion video; and CCITT H.261 (also known as Px64), for compression of video telephony and teleconferencing. All three of these standards employ a basic technique known as the discrete cosine transform (DCT), Developed by Ahmed, Natarajan, and Rao [1974]. Image compression using Discrete Cosine Transform (DCT) is one of the simplest commonly used compression methods. The quality of compressed images, however, is marginally reduced at higher compression ratios due to the lossy nature of DCT compression, thus, the need for finding an optimum DCT compression ratio. An ideal image compression system must yield high quality compressed images with good compression r...

As a renewable, sustainable and alternative fuel for compression ignition engine, biodiesel instead of diesel has been increasingly fuelled to study its effects on engine performances and emissions in the recent 15 years. Biodiesel is an alternative to petroleum-based fuels derived from vegetable oils, animal fats, and used waste cooking oil including triglycerides. Bio-diesel production is a very modern and technological area for researchers due to the relevance that it is winning everyday because of the increase in the petroleum price and the environmental advantages. Trans esterification is the most common method and leads to monoalkyl esters of vegetable oils and fats, now called bio-diesel when used for fuel purposes. In spite of having some other applications, recently it is being considered as one of the most promising alternative fuels in internal combustion engine. Also on the other hand increasing stringent emission regulation will make the use diesel very difficult in the...

Alcohols have been used as an additive to diesel fuel. Two methods of alcohol addition have been considered: blending and fumigation. The effects of both methods on the performance and emissions of diesel engine have been studied and compared. The analysis was based on the fuel injection and combustion characteristics derived from indicator diagrams. The pros and cons of both methods have been emphasized and the recommendations of their application provided.

A Dynamic model of Homogeneous Charge Compression Ignition (HCCI), based on chemical kinetics principles and artificial intelligence, is developed. The model can rapidly predict the combustion probability, thermochemistry properties, and exact timing of the Start of Combustion (SOC). A realization function is developed on the basis of the Sandia National Laboratory chemical kinetics model, and GRI3.0 methane chemical mechanism. The inlet conditions are optimized by Genetic Algorithm (GA), so that combustion initiates and SOC timing posits in the desired crank angle. The best SOC timing to achieve higher performance and efficiency in HCCI engines is between 5 and 15 degrees crank angle (CAD) after top dead center (TDC). To achieve this SOC timing, in the first case, the inlet temperature and equivalence ratio are optimized simultaneously and in the second case, compression ratio is optimized by GA. The model’s results are validated with previous works. The SOC timing can be predicted...

A tremendous amount of data is produced in medical imaging technology which is more challenging to save into a storage device and send through limited bandwidth over the internet. A useful image compression technique is required to solve the problem. In this paper, level-order height limited: a new lossless image coding technique has been proposed which builds a complete binary tree instead of an extended binary tree to encode an image and the probabilities are sorted in descending order and set in level-order traversal style. Finally, 0 and 1 are assigned to the left and right branches of the tree to encode an image. In this technique, each node of the tree contains a distinct symbol. The proposed procedure has been applied to some medical and benchmarked image. Average code length(ACL), compression ratio(CR), bits per pixel(BPP), mean squire error(MSE), pick signal to noise ratio(PSNR) and required execution time(RET) are used to measure the performance of the proposed method and compare with the state-of-art techniques. In the case of lossless coding, the proposed coding provides better results in almost every case than the state-of-art lossless coding schemes.

In the framework of the image compression by Wavelet Transforms, we propose a perceptual method by incorporating Human Visual System (HVS) characteristics in the quantization stage. Indeed, human eyes haven-t an equal sensitivity across the frequency bandwidth. Therefore, the clarity of the reconstructed images can be improved by weighting the quantization according to the Contrast Sensitivity Function (CSF). The visual artifact at low bit rate is minimized. To evaluate our method, we use the Peak Signal to Noise Ratio (PSNR) and a new evaluating criteria witch takes into account visual criteria. The experimental results illustrate that our technique shows improvement on image quality at the same compression ratio.

Vector data represents a map by its coordinate and Raster data represents a map by its pixel. Since these data types have very large data size, data compression procedure is a compulsory process. This paper compare the results from three different methodologies; GIS (Geographic Information System) vector map data compression using DP(Douglas-Peucker) Simplification algorithm, vector data compression based on Bin classification and the combination between two previous methods. The results shows that the combination between the two methods have the best performance among the three tested methods. The proposed method can achieve 4-9% compression ratio while the other methods show a lower performance.

This paper presents a GIS vector map data compression scheme based on hybrid polyline simplification method and SEC(spatial energy compaction). The proposed method extracts all layers which contain polylines in the GIS vector map and compress all polylines in extracted layers by the hybrid polyline simplification and SEC based on MAE(minimum area error) for each segment in the line. The proposed simplification and SEC increase the compression ratio while preserving the shape quality. We analyze the visual aspects and compression efficiency between the original GIS vector map and the compressed map. From experimental results, we verify that our method has the higher compression efficiency and visual quality than conventional methods.

The critical collisions in intermediate energy heavy-ion reactions are examined from both a microscopic and macroscopic viewpoint. In the microscopic description the proper tool is the extended TDHF approximation involving both the mean field and the particle collisions. To understand the underlying physics, the effect of the mean field and the effect of particle collisions are studied separately. It is found that th sudden increase in the density of the overlapping region can cause the volcano effect, leading to the complete disintegration of one of the nuclei. The self-consistent mean field also gives rise to the bunching instability when the two Fermi spheres of the colliding nucleons separate. The collision between nucleons, on the other hand, leads to irreversible dissipation, thermalization, and the possibility of a hydrodynamical description of the dynamics. Next is studied the dynamics of central collisions using the hydrodynamical description for many combinations of target...

The article discusses the possibility of using glycerol as an additive to the engine fuel in order to reduce the tendency of combustion knock, and thus to increase the octane number of a given fuel. Experimental tests were carried out on the UIT-85 research engine with a variable compression ratio from eight to eleven to test the intensity of the knock. The completely renewable fuel—the blend of glycerol with butanol in the ratio of 25 and 75%, respectively—was tested. A comparative analysis of the knock intensity was conducted with gasoline 95 and N-butanol tested as reference fuels. The developed method for knock analysis using the proposed knock indicator was also presented. The experimental results proved the proposed blend of N-butanol and glycerol reduces the knock intensity by more than 50% in the spark-ignition engine at a compression ratio of 10, maintaining engine performance at a similar level as it was for a gasoline-fueled engine. The results confirmed the thesis on the...

Data Compression can save some storage space and accelerate data transfer. Among many compression algorithm, Run Length Encoding (RLE) is a simple and fast algorithm. RLE can be used to compress many types of data. However, RLE is not very effective for image lossless compression because there are many little differences between neighboring pixels. This research proposes a new lossless compression algorithm called YRL that improve RLE using the idea of Relative Encoding. YRL can treat the value of neighboring pixels as the same value by saving those little differences / relative value separately. The test done by using various standard image test shows that YRL have an average compression ratio of 75.805% for 24-bit bitmap and 82.237% for 8-bit bitmap while RLE have an average compression ratio of 100.847% for 24-bit bitmap and 97.713% for 8-bit bitmap.

This study evaluated the compressibility of multislice CT (MSCT) datasets and its dependence on (1) slice thickness and (2) the use of three-dimensional (3D) vs. 2D JPEG2000 compression methods. Five thoracic CT datasets were obtained using a 16-detector MSCT scanner with a collimation of 0.75 mm (120 kVp, 90 mAs) and reconstructed at five slice thicknesses from 0.75 to 10.0 mm. These datasets were irreversibly compressed using a standard 2D JPEG2000 encoder and a developmental 3D JPEG2000 algorithm based on Part 2 of the JPEG2000 standard. Compression ratios ranged from 4:1 to 64:1. Image distortion was computed utilizing peak signal-tonoise ratio (PSNR) and the Sarnoff JNDmetrix visual discrimination model. For 2D compression, the thinnest sections were substantially less compressible than thicker sections for the same level of image quality, particularly at higher compression ratios. Applying 3D compression yielded consistently higher image quality in most cases compared to 2D compression at the same ratios. The advantage of 3D compression increased for thinner slices and higher compression ratios. These results indicate that 3D JPEG2000 (Part 2) compression offers substantial advantages over the current 2D JPEG2000 standard, yielding better quantitative image quality at similar compression ratios or comparable image quality at higher compression ratios. D 2004 Published by Elsevier B.V.

The region of image compression since it is applicable to various fields of image processing. The key goal of compression is to cut back the space for storage and decrease the transmission cost and maintain the visual quality of image. This paper presents fundamental approach for analysis and evaluating the image compression techniques. This paper describes the many techniques which can be used for image compression and describes about artifacts which can be consequence of compression and their reduction techniques. This paper presents a new Canny edge based restoration method to remove artefacts from compressed image. Firstly standard JPEG compression is used to compress the first image. Compressed image contains various visible artefacts like blurring artifacts, blocking artifacts and ringing artifacts. Then to remove ringing artifacts proposed method i.e. image restoration as a post processing method is used. Experimental effects of proposed method by use of various performance parameters are good.

This research paper proposes a method for the compression of medical images using an efficient hybrid algorithm. The objective of this hybrid (DWT,DCT and Huffman quantization) scheme is to calculate the compression ratio, peak signal to noise ratio and mean square error by changing the DWT level and Huffman quantization factor. The goal is to achieve higher compression ratio by applying different compression thresholds for the wavelet coefficient of each DWT band and then DCT with varying Huffman quantization factor while preserving the quality of reconstructed image. First DWT and DCT is applied on individual components RGB. After applying this image is quantized using Huffman quantization to calculate probability index for each unique quantity so as to find out the unique binary code for each unique symbol for their encoding.