Muhammad Kamran

Experimental investigation of ultra wideband diversity techniques for on-body radio communications

This paper presents an experimental investigations and analyses of ultra-wideband antenna diversity techniques and their efiect on the on-body radio propagation channels. Various diversity- combining techniques are applied to highlight; how the overall system performance may be enhanced. Diversity gain is calculated for flve difierent on-body channels and the impact of variation in the spacing between diversity branch antennas is discussed, with an emphasis on mutual coupling, correlation and power imbalance. Results demonstrate the repeatability and reliability of the analysis with error variations as low as 0.8dB. The study highlights the signiflcance of diversity techniques for non-line-of-sight propagation scenarios in body-centric wireless communications.

A novel domain optimization technique in fractal image compression

Fractal image compression is a lossy compression scheme that exploits the affine redundancy in images and represents them in the form of mathematical model. The scheme has capability of very high compression ratio, high resolution and fast decoding time. The encoding procedure, however, is computationally very expensive and thus requires long encoding time. The encoding procedure consists of dividing the image into range blocks and domain blocks, and then it takes a range block and matches it with the domain block by properly aligning the domain block. It repeats the above procedure for the entire domain pool and then encodes the range block in terms of domain block that is most similar to it. This paper is an effort to reduce complexity and accuracy of first part of the algorithm, i.e. range and domain block alignment and matching. The computation complexity of this process is mainly achieved by doing alignment and matching in Fourier domain using fast convolution technique. The accuracy is achieved by the ability if algorithm to find rotation angles that is not restricted to 90°, 180°, 270° and 360° and also we are able to find the translation of domain block with respect to range block that is often ignored in many fractal encoders in aligning and matching domain block with the range block.

Speaking monuments — design and implementation of an RFID based blind friendly environment

The research reported here, represents a navigation system for blinds - a compelling mobile application of wearable computing that would be not only a challenging task from research perspective, but also beneficial for society. The objective of this research is to create a portable, self-contained system that will allow visually impaired individuals to travel through familiar and unfamiliar environments without the assistance of guides. The user can get auditory clues about step-by-step walking guidance to move in an indoor environment. This paper focuses on the navigation design limited to a room and experiments show acceptable in-door accuracy. First portable prototype has been tested on a group of blind children from a training institute in Lahore, Pakistan. The real time experimentation results verify the significance of our designed system.

MSDCT Architecture Implementation with DA Based Optimized LUT

In this paper a modified scaled discrete cosine transform hardware implementation is presented which will be further utilized in video chip application. The hardware design is based on the description of the algorithm along with the proof of operational steps to complete inner product operation required for discrete cosine transform (DCT) application. This paper highlights and compares 8 times 8 pixels block DCT architecture of conventional design with our optimized design. Optimized hardware is presented by virtue of distributed arithmetic (DA) and contains multiplications based on computational sharing multiplier (CSHM) concept. DA is utilized for LUT size optimization which helps to keep the area of chip and complexity of connections reasonably small

Energy Efficiency Analysis of Hybrid-MAC Protocols with Application Constraints in Wireless Sensor Networks

Various energy and computational constraints for sensor nodes in wireless sensor networks have led to the development of many protocols with emphasis on medium access control (MAC) layer protocols. Several applications have already been envisioned for wireless sensor networks. This paper classifies the existing MAC protocols & the applications/ scenarios for wireless sensor networks. In addition the paper analyses and compares the application specific-ness of the existing Hybrid-MAC protocols depicting the effect of the inefficient behavior of these protocols if imposed on some other applications/ scenarios. Simulation results also verify their application dependency which highlights the need for a generalized, standardized & adaptive MAC protocol suitable for a wider range of applications. The paper concludes with some recommendations for such protocols.

A Novel Image Compression Architecture with proficient Layered scenario

The architecture proposed in this paper performs all inevitable operations effectively to compress the data for image processing. The given behavioral architecture is not only verified algorithmically but also gave clear snapshot of the facts hindering in the efficient operation of data transfer with appropriate results. Moreover, this paper is the continuation of concurrent compression pre coder design to which DCT coders are to be appended for transformation and compression operation. The compression scenario is tackled in the coders by utilizing adaptive Huffman coding scheme. The most distinguishable characteristic of proposed design is the pre-coder attachment to the coders working in any format, i.e., JPEG or MPEG. In either case the results obtained are reliable and significantly appreciable with respect to image quality to support proposed architecture even in a system with variable band widths

A novel vehicle-to-grid technology with constraint analysis-a review

This paper presents a detailed review of a vehicle-to-grid (V2G) technology, and analyzes its impacts on power distribution networks. It is shown in this study that a vehicle, equipped with the ability of a V2G application, offers various features such as regulation of active power, support for reactive power, load balancing, current harmonics filtering etc. These features can enable ancillary services including, spinning reserve and control of voltage and frequency. However, the technology of V2G also creates challenging issues, for instance, degradation of batteries, communication overhead between an EV and a grid, changes in whole infrastructure of a distribution network (DN). This paper shows the present scenarios and analyze the impact of implementation V2G & G2V modes on DNs. V2G system have an impact on major factors of electric grid like reliability, efficiency, losses, and system stability. Our study also shows that the economic benefits of a V2G technology heavily depend on the strategies of charging and vehicle aggregation.

Design of a compact wearable single-arm spiral antenna for satellite communications

Spiral antennas are a popular choice for satellite communication systems due to their small size, broadband, circular polarisation and high gain. This paper presents a novel design of an Archimedean single-arm spiral antenna fed through a coaxial feed for operation in X and Ku frequency bands covering 8 GHz to 18 GHz frequencies. The antenna has very good impedance matching (better than -10 dB) throughout the frequency range, good right hand circular polarisation (≤3 dB) and offers a maximum peak gain of 9.1 dBi. The radiation characteristics, efficiency, gain and compact size make this antenna suitable for rigid, mobile and airborne terminals. The compact size also makes the proposed antenna good candidate for wearable/poartable wireless communication devices.

An efficient layered data compression scheme with constraint analysis

Layered image transmission is successfully adopted for different system applications. Generally, in this technique, image is divided into number of layers for easy and fast transmission keeping the concept of multi-description representation. This configuration helps to make overall system adaptive with respect to different systems bandwidth. Proposed data compression layered schemes architecture not only works with JPEG but also with MPEG image formats. It includes all necessary steps and precautions to handle possible disturbances in image compression by analyzing different parameters affecting image quality and transmission time. In this paper, behavioral model of complete image compression scheme is discussed starting from image extraction from source, layering of image matrix, generating separate pixel layers for concurrent compression followed by efficient coder operation. This paper also addresses different parameters, which improve image quality with different constraints and limitations encountered during design verification. This proposed scheme is comprised of pre-coder, efficient transformation scheme followed by adaptive Huffman encoding/decoding in conjunction with quantization of image matrix which makes overall compression system lossy in nature. Due to flexibility of operation, this scheme can be applicable in different applications like Robot vision and real time video compression, etc. The results obtained after mathematical analysis and simulation are found useful to prove efficiency of layered compression scheme.

Key design features of multi vacuum glazing for windows: A review

The use of vacuum glazed windows is increasing due to their application in mod-ern building design. Among various types of vacuum glazed windows reported in literature, thermal transmittance of single glass sheet (conventional window) i. e 6 W/m2k is reduced by 66 and 77% using air filled double glazed and air filled triple glazed windows, respectively. Using low emittance coatings thermal transmittance of double glazed windows is reduced by 53%, however it offsets the visibility by reduc-ing light transmittance by 5%. Stresses due to temperature/pressure gradients if not eliminated may lead to reduction in service life of vacuum glazed windows. Vacuum created between the glass sheets is used to reduce conductive heat transfer. Degrada-tion in the vacuum is caused by number of factors such as, permeation of gaseous molecules through glass sheets, leakage through sealing, thermal/optical desorption, and photo-fragmentation of organic species have been critically reviewed and future trends are outlined.