Memristor crossbars offer reconfigurable non-volatile resistance states and could remove the speed and energy efficiency bottleneck in vector-matrix multiplication, a core computing task in signal and image processing. Using such systems to multiply an analogue-voltage-amplitude-vector by an analogue-conductance-matrix at a reasonably large scale has, however, proved challenging due to difficulties in device engineering and array integration. Here we show that reconfigurable memristor crossbars composed of hafnium oxide memristors on top of metal-oxide-semiconductor transistors are capable of analogue vector-matrix multiplication with array sizes of up to 128 × 64 cells. Our output precision (5–8 bits, depending on the array size) is the result of high device yield (99.8%) and the multilevel, stable states of the memristors, while the linear device current–voltage characteristics and low wire resistance between cells leads to high accuracy. With the large memristor crossbars, we demonstrate signal processing, image compression and convolutional filtering, which are expected to be important applications in the development of the Internet of Things (IoT) and edge computing.

Analogue signal and image processing with large memristor crossbars

The discrete cosine transform (DCT), introduced by Ahmed, Natarajan and Rao, has been used in many applications of digital signal processing, data compression and information hiding. There are four types of the discrete cosine transform. In simulating the discrete cosine transform, we propose a generalized discrete cosine transform with three parameters, and prove its orthogonality for some new cases. A new type of discrete cosine transform is proposed and its orthogonality is proved. Finally, we propose a generalized discrete W transform with three parameters, and prove its orthogonality for some new cases. Keywords: Discrete Fourier transform, discrete sine transform, discrete cosine transform, discrete W transform Nigerian Journal of Technological Research , vol7(1) 2012

On discrete cosine transform

Memristor with tunable non-volatile resistance offers in-memory computing capability that avoids the von-Neumann bottleneck. However, large-scale experimental demonstration to this end is yet to be implemented due to the immaturity of the device and integration technologies. Here in this paper we report our recent process in analog computing using analog-voltage-amplitude-vector input and analog-memristor-conductance matrix, with applications in signal and image processing. The vector matrix multiplication is processed in the memristor crossbars in one step, with 5–8 bit precision depending on the array size. The demonstration is made possible by high memristor yield (99.8%), stable multilevel memresistance states, linear current-voltage (IV) relation in the operation range, and low wire resistance between the cells.

Large Memristor Crossbars for Analog Computing

Introduction of computer technology in various fields has simplified the job of human being but has also resulted in large amount of digital data. The challenge lies in managing this huge amount of data, i.e. storing and retrieving it. The storing resources required for it also increases the cost of the overall system. If one can use some technique to reduce this digital data without losing the original information, then the cost can be cut down to some extent. The process of reducing data size without losing the vital information is known as data compression. There are various data compression techniques one can use. These techniques can be classified into two types i.e. Lossy and Lossless compression. In this paper some of the image compression techniques are discussed in detail.

/pdf/a-survey-of-image-compression-techniques-418re4nq2o.pdf

A Survey of Image Compression Techniques

DCT based JPEG compression is a widely used standard for lossy image compression. DCT concentrates energy into lower order coefficients. It removes redundancy between neighbouring pixels which leads to uncorrelated transform coefficients which can be encoded independently. There is high computational complexity in DCT. DHT is a real valued transform whose forward and inverse transforms are same except for a an inclusion of a scale factor in the inverse transform. DHT reduces the computational complexity of JPEG compared to DCT. DHT doesn’t require a dequantizer at the decoder, since a new quantization technique known as energy quantization is used. It speeds up the encoding procedure, reduces hardware as well as makes the implementation simpler. The quality of the reconstructed image is very good which is verified using MATLAB i.e. the PSNR is improved and the MSE is reduced.

/pdf/jpeg-image-compression-using-dct-and-dht-and-comparison-of-12hf8htoem.pdf

JPEG Image Compression using DCT and DHT and Comparison of Both Techniques based on Mean Square Error and Peak Signal to Noise Ratio

Digital images contain large amount of information that need evolving effective techniques for storing and transmitting the ever increasing volumes of data. Image compression addresses the problem by reducing the amount of data required to represent a digital image. Image compression is achieved by removing data redundancy while preserving information content. In this paper, a new alternative method for simultaneous image acquisition and compression called adaptive compressed sampling. It also extended the need for image reconstruction on compressed images. Image reconstruction has to be defined in this context. whereas Image enhancement strives to bring out certain features in an image to simplify the extraction of image information, image reconstruction is the attempt to retrieve information that has been lost or obscured in the imaging process itself.

/pdf/a-new-entropy-encoding-algorithm-for-image-compression-using-5dudhrssgb.pdf

A new entropy encoding algorithm for image compression using dct

Compare the effect of video assisted teaching VS lecture method on knowledge regarding Glasgow coma scale (GCS) among nursing students

Background. Gait analysis is a systematic study of human locomotion that involves evaluating body motions, body mechanics, and muscle activity. Objective. To analyze spatiotemporal and kinematics variables among overweight children and normal children. Methodology. Non-Experimental study, convenient sampling, sample size was 30. Both boys and girls with 12 to 14 years of age were included in the study. Procedure. Participant were selected according to BMI for analyzing the normal and overweight children, based on these two groups were divided. GROUP A – Normal children and GROUP B – Overweight children. Outcome measures. Spatiotemporal and kinematics variables were assessed by using 2D gait analysis with software from Auptimo technologies. Results. Gait analysis of normal children shows significant difference in ankle plantar flexion, knee flexion and hip flexion in lateral view and in anterior view shows knee adduction, in posterior view shows ipsilateral pelvic drop and rear foot eversion at p < 0.05. In overweight children shows that ankle dorsiflexion, knee hyperextension, hip extension in lateral view, and in anterior view shows knee adduction and in posterior view shows that contralateral pelvic drop and rear foot eversion. In spatiotemporal parameters of overweight children shows reduced cadence and gait cycle compare to normal children at p < 0.05. Conclusion: This study concludes the normal and overweight children shows marked changes in ankle, knee and hip joint, knee abduction/adduction, pelvic drop, rear foot angle and spatiotemporal parameters.

Two-dimensional analysis of gait parameters on normal and overweight children – an observational study

Background. Duchenne Muscular Dystrophy (DMD), an X linked disorder resulting in respiratory insufficiency, caused by progressive respiratory muscle weakness particularly in diaphragm. During this pandemic, Telerehabilitation played a major role among patients, especially disabled children. OBJECTIVE: To find out the effect on the pulmonary function in DMD children by training the respiratory muscles by telephysiotherapy. Methodology. Non Experimental design, Case series- pre and post test type. Convenient sampling, sample size was 5. Boys and girls between 9 and 16 years of age were included in the study. Procedure. 5 subjects were selected based on the inclusion and exclusion criteria and were trained for one minute with minimum resistance using ultrabreathe through Telephysiotherapy which is repeated for 3 times in a session with a rest period of 20–30 seconds for six weeks. Outcome measure. Pulmonary Function test. Results. The results of this study shows increased mean value of post test Tidal volume, Forced Vital Capacity, Inspiratory time/Respiration time and Tidal Volume / Inspiration time compared with pre test, whereas other parameters like Duration of Inspiration, Total Lung Volume, Inspiratory Capacity, Forced Expiratory Volume1 does not increased. Conclusion This study concluded that the Duchenne Muscular Dystrophy children improved in Tidal Volume, Forced Vital Capacity, Tidal Volume/Inspiration Time, and Inspiration Time/Respiration Time whereas all other parameters such as Duration of Inspiration, Total lung volume, Inspiratory capacity and Forced Expiratory volume1 maintained after 6 weeks of respiratory muscles training with ultrabreathe device.

D. Malarvizhi

Papers

A new entropy encoding algorithm for image compression using dct

Compare the effect of video assisted teaching VS lecture method on knowledge regarding Glasgow coma scale (GCS) among nursing students

Two-dimensional analysis of gait parameters on normal and overweight children – an observational study

Effect of respiratory muscle training using Ultrabreathe device on pulmonary function in Duchenne Muscular Dystrophy through telephysiotherapy