AN ADAPTIVE INFORMATION DISSEMINATION MODEL FOR VANET COMMUNICATION

Vehicular ad hoc networks (VANETs) have been envisioned to be useful in road safety and many commercial applications. The growing trend to provide communication among the vehicles on the road has provided the opportunities for developing a variety of applications for VANET. The unique characteristics of VANET bring about new research challenges

Characterisation of human body and environmental effects on the performance of mobile terminal antennas

PhDProvision of efficient services to the user anywhere at anytime is being a centre of research and development in Wireless Personal Area Networks (WPAN) and Wireless Body Area Networks (WBAN). Antenna is the essential part of WPAN/WBAN applications that got affected by two major factors: human body presence and nature of the surrounding environment. The presence of the human body in the proximity of the antenna causes electromagnetic (EM) reflections from the body surface and absorptions in the lossy body tissues resulting in antenna detuning, radiation pattern degradations and impedance mismatch. On the other hand, incident radio waves undergo reflections, difractions and scattering from the surrounding environment objects including buildings, trees, vehicles and ground, causing multipath fading. The thesis gives an overview of the main investigations, results and analyses accomplished in a study concerning the commercially available Bluetooth and GPS antennas working in the vicinity of the human body. Detailed numerical modelling process is adopted followed by measurements for validation. The thesis highlights the role of surface waves as a potential transmission medium in an on-body Bluetooth wireless communication link taking into account the effects of antenna-body separations and presence of the surrounding objects blocking the direct communication path. The thesis also presents a novel statistical model to evaluate the performance of GPS mobile terminal antennas in the multipath environment. This model characterises the antenna performance and identifies the key factors that can be used to enhance it, in a real working environment outside an anechoic chamber. The study also deals with presence of the human body in the multipath environment and its effects on the operation of the GPS antennas

Repair Of Uv-irradiated Plasmids In Escherichia Coli And Chinese Hamster Cells

Nucleotide excision repair of DNA, demonstrated by the removal of cyclobutane pyrimidine dimers (CPDs), proceeds much more rapidly in genes undergoing transcription than in inactive genes and this rapid repair is confined to the strand being transcribed. The phenomenon is referred to as transcription-repair coupling and it has been demonstrated to occur in the chromosomes of mammalian cells, yeast cells and Escherichia coli. It was of interest to examine the repair characteristics of plasmids both in E. coli and Chinese hamster (CHO) cells.;Some of the findings obtained with the E. coli system were the following: The Rec A function is necessary for the efficient repair of pGA293 in E. coli. Unexpectedly, both strands of the 3.5 Kbp and 2.4 Kbp domains of pGA293 were repaired with the same kinetics. An examination of the sequences of the designated non-transcribed strands revealed the presence of potential promoter sequences which left open the possibility that these strands were in fact being transcribed. The rates of repair of both strands of the 3.5 Kbp and 2.4 Kbp domains were slower than that reported for the transcribed strand of the E. coli chromosomal lacZ gene. However, there were 10 copies of the pGA293 genes but only 1 copy of the chromosomal gene, and this along with the greater number of CPDs in the plasmid DNA, could account for the slower rate of repair. These considerations made it likely that for both strands in the 3.5 Kbp and 2.4 Kbp domains transcription repair coupling was being observed. For the 3.0 Kbp domain, the repair rate for the non-transcribed strand was slower than that for the transcribed strand and was the same as the repair rate reported for the non-transcribed strand of the E. coli chromosomal lacZ gene. This suggests that the transcribed strand of the 3.0 Kbp domain was undergoing coupled repair while the other strand was not.;Using the CHO system, the following information was obtained: Expression of {dollar}\beta{dollar}-galactosidase from indicated pGA293 recovered readily after transformation, indicating that repair had taken place. However, it was not possible to demonstrate removal of CPDs from the 3.0 Kbp domain of pGA293 which contains the transcribed {dollar}\beta{dollar}-galactosidase gene. (Abstract shortened by UMI.

Green Communications: Techniques and Challenges

Green technology has drawn a huge amount of attention with the development of the modern world. Similarly with the development in communication technology the industries and researchers are focusing to make this communication as green as possible. In cellular technology the evolution of 5G is the next step to fulfil the user demands and it will be available to the users in 2020. This will increase the energy consumption by which will result in excess emission of co2. In this paper different techniques for the green communication technology and some challenges are discussed. These techniques include device-to-device communication (D2D), massive Multiple-Input Multiple-Output (MIMO) systems, heterogeneous networks (HetNets) and Green Internet of Things (IoT)

Linking poverty and environment as causes of conflict: a case study of Pakistan

This paper presents a theoretical analysis of an International conflict i.e. East Pakistan Crisis, 1971, and reveals that un-equal development creates conflict in society. Natural resource scarcity and environmental degradation can also become a source of conflict, so marginalized and excluded people fight for their rights through non-peaceful means.This essay supports the theoretical approaches of poverty, environment, and conflict nexus and reveals that un-equal development and resources scarcity deepens the poverty and creates conflicts in the society, causing harm to the environment.The degraded environment deepens the poverty as environment and poverty are interlinked and poor has limited choices other than to degrade the environment for their survival.This vicious downward spiral link of poverty and degradation of environment requires working extensively for poverty alleviation to reverse the environmental decline

Multiband split-ring resonator based planar inverted-F antenna for 5G applications

5G, the fifth generation of wireless communications, is focusing on multiple frequency bands, such as 6GHz, 10GHz, 15GHz, 28GHz, and 38GHz, to achieve high data rates up to 10 Gbps or more.The industry demands multiband antennas to cover these distant frequency bands, which is a task much more challenging. In this paper, we have designed a novel multiband split-ring resonator (SRR) based planar inverted-F antenna (PIFA) for 5G applications. It is composed of a PIFA, an inverted-L parasitic element, a rectangular shaped parasitic element, and a split-ring resonator (SRR) etched on the top plate of the PIFA.The basic PIFA structure resonates at 6GHz. An addition of a rectangular shaped parasitic element produces a resonance at 15GHz. The introduction of a split-ring resonator produces a band notch at 8GHz, and a resonance at 10GHz, while the insertion of an inverted-L shaped parasitic element further enhances the impedance bandwidth in the 10GHz band. The frequency bands covered, each with more than 1GHz impedance bandwidth, are 6GHz (5–7GHz), 10GHz (9–10.8GHz), and 15GHz (14-15GHz), expected for inclusion in next-generation wireless communications, that is, 5G. The design is simulated using Ansys Electromagnetic Suite 17 simulation software package.The simulated and the measured results are compared and analyzed which are generally in good agreement

Design of a Finger Ring Antenna for Wireless Sensor Networks

Body-centric communications have become very active area of research due to ever-growing demand of portability. Advanced applications such as; health monitoring, tele-medicine, identification systems, performance monitoring of athletes, defence systems and personal entertainment are adding to its popularity. In this paper, a novel wearable antenna radiating at 5 GHz for the body-centric wireless sensor networks has been presented. The antenna consists of a conventional microstrip patch mounted on a gold base and could be worn in a finger like a ring. CST Microwave Studio is used for modelling, simulation and optimisation of the antenna. The simulated results show that the proposed antenna has a -10 dB bandwidth of 90.3 MHz with peak gain of 6.9 dBi. Good performance in terms of bandwidth, directivity, gain, return loss and radiation characteristics, along with a miniaturised form factor makes it a very well suited candidate for the body-worn wireless sensor applications

Tri-band millimetre-wave antenna for body-centric networks

This paper presents design of a tri-band slotted patch antenna operating at millimetre-wave frequencies of 28 GHz, 38 GHz and 61 GHz. The proposed antenna carries an overall size of 5.1mm×5mm×0.254mm employing a single layer, slotted patch structure combining L- and F-shaped slots. It is excited by a single-feed microstrip line. The antenna is tested in free space as well as in wearable configurations and results show that it offers a good impedance matching, sufficient -10 dB bandwidth and wide radiation coverage at the three bands of interest effectively countering the effects of human body presence. It achieves a peak gain of 7.2 dBi in off-body and 8.3 dBi in on-body configuration. Minimum efficiency values are observed to be 85% in off-body while 54% in on-body scenarios. A comparative analysis with published relevant work shows that the proposed antenna is inexpensive, easy to integrate and works efficiently in tri-band wearable and implantable arrangements. These features make it a good candidate for current and future applications of Body-centric Networks operating at millimetre-wave ranges