Image Compression using Discrete Cosine Transform & Discrete Wavelet Transform

Image Compression addresses the problem of reducing the amount of data required to represent the digital image. Compression is achieved by the removal of one or more of three basic data redundancies: (1) Coding redundancy, which is present when less than optimal (i.e. the smallest length) code words are used; (2) Interpixel redundancy, which results from correlations between the pixels of an image & (3) psycho visual redundancy which is due to data that is ignored by the human visual system (i.e. visually nonessential information). Huffman codes contain the smallest possible number of code symbols (e.g., bits) per source symbol (e.g., grey level value) subject to the constraint that the source symbols are coded one at a time. So, Huffman coding when combined with technique of reducing the image redundancies using Discrete Cosine Transform (DCT) helps in compressing the image data to a very good extent. The Discrete Cosine Transform (DCT) is an example of transform coding. The current JPEG standard uses the DCT as its basis. The DC relocates the highest energies to the upper left corner of the image. The lesser energy or information is relocated into other areas. The DCT is fast. It can be quickly calculated and is best for images with smooth edges like photos with human subjects. The DCT coefficients are all real numbers unlike the Fourier Transform. The Inverse Discrete Cosine Transform (IDCT) can be used to retrieve the image from its transform representation. The Discrete wavelet transform (DWT) has gained widespread acceptance in signal processing and image compression. Because of their inherent multi-resolution nature, wavelet-coding schemes are especially suitable for applications where scalability and tolerable degradation are important. Recently the JPEG committee has released its new image coding standard, JPEG-2000, which has been based upon DWT

Radar Pulse Compression Using Frequency Modulated Signal

Range resolution for given radar can be improved by using very short pulses. But utilizing short pulses decreases the average transmitted power. To solve these problems pulse compression technique is used. It consists of two types of correlation process: matched filtering and stretch processing. Generally, we use matched filtering for narrowband signal and stretch processing for wideband signals. LFM signal is used in both the process as its bandwidth is independent of its pulse width. In this thesis we have analyzed two pulse compression technique and effect of time bandwidth product, Doppler shift on LFM signal passed through different windows. In radar masking effect is observed due to hiding of the far target’s weak echo by near target’s strong echo. Its removal is done by subtracting a replica of nearby target echo from the received signal. Matched filtering and stretch processing methods are used for this purpose

POST COVID MANAGEMENT OF ASTHMA IN CHRONIC ASTHMA PATIENT

Asthma is defined as a chronic inflammatory disease of the airways. The chronic inflammation is associated with airway hyper responsiveness (an exaggerated airway narrowing response to triggers, such as allergens and exercise), that leads to recurrent symptoms such as wheezing, dyspnea (shortness of breath), chest tightness and coughing. Asthma is associated with T helper cell type-2 (Th2) immune responses, which are typical of other atopic conditions. Various allergic (e.g., dust mites, cockroach residue, furred animals, moulds, pollens) and non-allergic (e.g., infections, tobacco smoke, cold air, exercise) triggers produce a cascade of immune-mediated events leading to chronic airway inflammation. The Present Review Discuss and Focus about the various Risk factor associated with Covid 19 influenced Asthma Patient with their Possible Management

Surface-analyte interaction as a function of topological polar surface area of analytes in metal (Cd, Al, Ti, Sn) sulfide, nitride and oxide based chemiresistive materials

Material surface - analyte interactions play important roles in numerous surface mediated processes including gas sensing. However, effects of topological polar surface area (TPSA) of target analytes on surface interactions during gas sensing have been so far largely disregarded. In this work, based on experimental observations on cross-sensitivity in cadmium sulfide (CdS) nanoparticle based room temperature gas sensor, we found that for reactions with similar Energy Rate of Surface Interaction (ERSI), unexpected quadratic correlation exists between sensing response of CdS and TPSA of analytes. From general understanding and as reported earlier in case of drug absorption through surface of membranes, it is expected that surface interactions would decrease with increasing TPSA of analytes. Our results imply that for certain TPSA range, sensor surface-analyte interactions actually increase with increasing TPSA before it finally starts decreasing. Further experiments on four other diverse material systems like AlN, SnO2, TiO2 (Anatase) and Vanadium-doped SnO2 showed similar trend, revealing generalized picture of TPSA dependence of sensor surface-analyte interactions. A physical explanation behind the parabolic relation has been provided based on electrostatic energy minimization of interacting polar fields. Above finding is anticipated to pave way to achieve improved surface interactions and highly selective sensing performances consecutively

Poly aniline (PANI) loaded hierarchical Ti1−xSbxO2 rutile phase nanocubes for selective room temperature detection of benzene vapor

Benzene is one of the aromatic yet hazardous hydrocarbons that are deceptive under their sweet odor. Even in low ppm concentration, benzene vapor in ambient surroundings have been proven to be a major human carcinogen, primarily responsible for leukemia. Often found along with traces of toluene and xylene which have similar molecular structures, selective detection of low concentration benzene, particularly at room temperature is a major challenge. In this work, using the idea that transition from uni-faceted to bi-faceted crystal growth shall induce a change in morphology from spherical to cubical; antimony doped rutile TiO2 nanocubes were synthesized and employed in benzene vapor detection. While the PANI loaded antimony doped (0.03) TiO2 nanocubes showed an enhanced 80% response to 2 ppm benzene in air at room temperature, it was selective (up to 7 times more) against 2 ppm toluene and xylene vapor. The sensors were highly stable against humidity and also reusable for a considerable span of time. The role of specificity in exposed cubical facet has been explained for eliminating cross-sensitivity in benzene detection phenomenon

Ammonia Sensing by Sn1-xVxO2 Mesoporous Nanoparticles

Chemiresistive gas sensing by metal oxide based materials has been usually explained in terms of surface chemistry and band structure modifications due to factors such as chemical composition, particle surface to volume ratio, material morphology, temperature, and surface oxygen vacancy. In this work, keeping parameters such as particle size, morphology, surface area, temperature, and surface oxygen vacancy fixed, we have for the first time attempted to delineate quantitatively the role of crystal structure and surface electronic states in improving gas sensing responses of doped nanosized metal oxide samples. While vanadium-doped tin oxide samples show a nearly 4-fold increase in 10 ppm ammonia sensing responses, the Sn0.696V0.304O2. sample shows similar to 1.2 times more sensing response as compared to Sn0.657V0.343O2. The ammonia sensing behavior has been found to be directly correlated to crystal structures and concentrations of various oxidation states of vanadium dopants present in the studied samples. Detailed comparative analysis of crystal and electronic structures of the samples has revealed the mechanism of enhancement in the ammonia sensing behavior of vanadium-doped tin oxides. It is expected that similar mechanisms might be responsible for enhancement in gas sensing properties of other metal oxide based systems

Parametric Appraisal of Electrochemical Machining of AISI 4140 Chromoly steel using Hybrid Taguchi - WASPAS - Sunflower optimization algorithm

Electrochemical machining (ECM) is a significant technique for getting rid of metal that employs anodic dissolution to get complex contours and deep, precise holes, mostly in the components used in automotive or aerospace sectors. To achieve such high surface characteristics, the selection of factors is important. This work deals with the ECM of AISI 4140 Chromoly steel to investigate the surface roughness and material removal rate (MRR) on the machined specimen using a copper tool electrode. Factors like voltage, signal, and feed rate were optimized by hybrid optimization techniques. To acquire optimal factor configurations, the Taguchi-based WASPAS approach was utilised, accompanied by the Sunflower optimisation methodology. ANOVA was then used to determine the component that was the most impactful factor. A confirmation test is used to signify the outcomes of electrochemical machining. It was revealed that feed rate was among the most significantly relevant factors in affecting surface roughness and MRR. Also, all the optimization approaches provided similar predictions and agreed with the results fetched by the previous research

pH-regulated hydrothermal synthesis and characterization of Sb4O5X2 (X = Br/Cl) and its use for the dye degradation of methyl orange both with and without light illumination

A pH-regulated hydrothermal synthesis method was employed to synthesize Sb4O5Br2 and Sb4O5Cl2 crystallites. Characterization is done by single crystal X-ray diffraction, powder X-ray diffraction, infra-red spectroscopy, scanning electron microscopy and DFT studies. The compounds crystallize in monoclinic symmetry with a P2(1)/c space group. Complete structural analysis of the Sb4O5Br2 compound by using single crystal X-ray diffraction data is performed for the first time and a comparative study with Sb4O5Cl2 is also discussed. The SEM study reveals that the surface morphology changes with the variation of pH for bromide compounds, whereas pH change does not affect the morphology of the chloride analogues. Electronic band structures of the synthesized oxyhalides were investigated in order to understand their catalytic effects in the dye degradation reactions in dark as well as sunlight conditions