Rajneesh Randhawa

Monitoring and Compensation of Optical Telecommunication Channels by using Optical Add Drop Multiplexers for Optical OFDM System

Abstract This paper forces on the monitoring and compensation of optical telecommunication channels by using Optical add drop multiplexers (OADM) in an Optical orthogonal frequency division multiplexing (OOFDM) system. An adaptive fiber nonlinearity precompensation (AFNP) scheme is also proposed to solve the fiber nonlinearity in coherent optical orthogonal frequency division multiplexed networks (CO-OFDM). Optical performance monitoring (OPM) at end-terminals is applied to channel identification in this paper. It is considered to be high efficiency and a cost efficient technique in low-dynamic system.

ARMM: Adaptive Resource Management Model for Workflow Execution in Clouds

Cloud offers computational resources as a utility to execute dependent tasks ensemble as an application workflow, where each task has a different resource requirement. Resource management frameworks are required to dynamically provision resources to enable scalability and seamless execution of workflows. In this paper, an adaptive resource management model is presented, which allocates and reschedule the resources based on their usage history and performance metrics. It further makes decisions to adapt workflow tasks to optimize deadline, budget and resource performance. A case study using different workflows is used to describe the model in a simulated environment considering various run time scenarios.

Cross-Layer Designs in Wireless Sensor Networks

Ever growing penetration of wireless networks in our day-to-day lives underline new challenges in the design of communication protocols. Traditional reference models designed for wired networks follow strict layered doctrine. But by changing times, a paradigm shift from wired to wireless networks, opened a plethora of both options and challenges before us. However, lack of communication among adjacent layers of these reference models, limits the performance of wireless networks especially wireless sensor networks to great extent. To overcome such limitations, optimization of these layers through cross-layer approach has been proposed. This chapter outlines requirements, prevalent practices and presents challenges in standardized architecture. Afterwards a cross-layer solution through inter and intra layer communication and optimization of layers and a framework for next generation wireless networks has been proposed.

Enhancing WSN Lifetime Using TLH: A Routing Scheme

A Wireless Sensor Network (WSN) consists of sensor nodes which are distributed over the network, where each sensor node composed of sensing unit along with limited computational power, low storage capacity and limited non-rechargeable battery source, resulting WSN to be energy constrained. In the proposed work a heterogeneous network is considered, in which uniformly placed nodes are divided into two levels of heterogeneity on the basis of energy. For the sake of long network lifetime, transmission to BS is done via Cluster Heads (CH’s) resulting in faster drainage of CH node. So to manage the load on CH’s, a new static clustering technique gained into its inception which includes CH’s of higher energy, that in addition to increase network lifetime, also will reduce hop count to BS. The simulation result shows a significant improvement in stability as well as network lifetime of the proposed technique.

Cuckoo search based workflow scheduling on heterogeneous cloud resources

Cloud is emerging as a utility paradigm for effectively executing large scale distributed workflows with huge computation and data transfer requirements. The heterogeneity in cloud resources makes it challenging for scheduling workflow tasks effectively. The goal is to find an optimized mapping between individual workflow tasks and cloud resources, based on various quality of services. The dependencies in workflows make it challenging for scheduling task with precedence constraints. The tasks need to be scheduled in such way that it minimizes the makespan and execution cost for workflow. This paper proposes a workflow scheduling algorithm based on cuckoo search for finding a schedule for workflow tasks. The tasks are added to execution list after prioritizing them according to the length of execution and dependencies. Cuckoo search algorithm is adapted to find an optimal mapping of workflow tasks on cloud resources. The workflow is executed within a user defined deadline while optimizing the overall makespan. The results are compared with the meta-heuristic population based Particle Swarm Optimization and heuristic technique Heterogeneous Earliest Finish Time. The results of the proposed algorithm indicate that it outperforms the approaches considered for comparison.

Flat-Gain C+L Split-Band Hybrid Waveguide Amplifier for Dense Wavelength Division Multiplexed System at Reduced Channel Spacing

A split-band Hybrid Waveguide Amplifier is proposed using parallel configuration of Er-doped and Er-Yb co-doped waveguide amplifier for C+Lband dense wavelength division multiplex system.This HWA gives a larger gain with little power/gain variations.