P. Suresh Varma

Performance analysis of cloud computing using Queuing models

Cloud computing is a new economic computing paradigm in which information and computer resources can be accessed from a Web browser by customers. The process of a job entering into the cloud schedule is generally in the form of queue, so that each user needs to wait until the earlier users are being served. Whenever a new job enters the cloud buffer, the queue length increases so the waiting time. There are many methods like FIFO, Priority scheduling, Round robin etc to dispatch the job from buffer to a machine. In this paper, we developed and analyzed a cloud and provided service using Queuing analogy. The transient analysis of cloud studied by deriving various parameters like mean queue length, Utilization, Throughput and Mean Waiting Time in the cloud. It is observed that using queuing theory in the service has tremendous influence on Mean Delay, Throughput and Congestion Control.

Performance measure of multi stage scheduling algorithm in cloud computing

Scheduling user requests in cloud computing for resource provision is key process in cloud computing. In cloud computing sometimes user request has to be processed with a series of virtual machines from the available resources. Each request ri (1<;=i<;=n) in cloud environment has to complete its workflow on a virtual machine of type VM1 for an instance of Ti1 units time, later on a virtual machine of type VM2 for an instance of Ti2 units of time, and so on, at end on a virtual machine of type VMm for an instance of Tim units of time. Scheduling the requests using FCFS scheduling has the highest Average waiting time and Total elapsed time. The present paper presents a novel approach in cloud computing for resource request scheduling by applying Johnsons Scheduling algorithm to reduce average waiting time and total elapsed time. The simulation results show the significant influence on average waiting time and total elapsed time.

A Novel Pairwise Key Establishment and Management in Hierarchical Wireless Sensor Networks (HWSN) Using Matrix

Key Management is an important challenging issue in wireless sensor networks to provide the confidentiality for the sensitive data which is sensed by the sensors from various fields. There are so many resource constraints for wireless sensor networks, implementing key management scheme in WSN. In general many key management schemes are proposed for Computer Networks like ECC, Diffie-Hellman, RSA and public key based schemes, but all are not suitable for wireless sensor networks. WSNS are suitable for many applications like Smart homes, Automation, Vehicular traffic management, Habitat Monitoring, Precision agriculture, Disaster detection and Surveillance. All the applications need secure communication and must protect from the eavesdropping, key compromising, sensor node capture attack, and message authentication. In this paper, we propose A Novel Pairwise Key Establishment and Management in Hierarchical Wireless Sensor Networks (HWSN) Using Matrix to prevent all the above attack and to achieve network connectivity, scalability, and resilience for the network. This scheme is used for the heterogeneous sensor networks. In this scheme, Base station prepares the key matrices for Cluster heads and Sensor nodes and generates the key chains for both cluster head and sensor nodes and preloaded before deployment. Our scheme prevents the following attacks: sensor capture attacks, key compromising attacks, malicious node attacks.

ASH-160

Cryptographic hash function plays a pivotal role in many parts of cryptographic algorithms and protocols, especially in authentication, non-repudiation and data integrity services. A cryptographic hash function takes an input of arbitrary large size message and produces a fixed small size hash code as an output. In the proposed hash algorithm ASH-160 (Algorithm for Secure Hashing-160), each 512-bit block of a message is first reduced to 480-bit block and then divided into ten equal blocks and each one is further divided into three sub-blocks of 16-bits each. These three sub-blocks act as three points of a triangle, which are used in Area calculation. The calculated area values are in turn processed to generate message digest. ASH-160 is simple to construct, easy to implement and exhibits strong avalanche effect, when compared to SHA1 and RIPEMD160.

Performance Evaluation of Two Stage Scheduling Algorithm in Cloud Computing

Cloud computing is an evolutionary approach that completely changes how computing services are produced, priced and delivered. Cloud computing allows to access services that reside in a distant datacenter, other than local computers. Resource provisioning is the key process in cloud computing. The Virtual Machine (VM) is a software implementation of a machine that executes programs like a physical machine. Two stage scheduling is a novel approach in cloud computing. In this case a job may request two virtual machines in sequence to complete their needs. This paper presents a novel two stage scheduling algorithm to schedule the given job requests in cloud environment by extending Johnson’s Scheduling algorithm. Simulation results show that this algorithm reduces average waiting time and total elapsed time when compared to other scheduling algorithms.

Transient Analysis of Communication Network Model with Homogeneous Poisson arrivals and Dynamic Bandwidth Allocation

models play a dominant role in many communication systems for optimum utilization of the resources. In this paper, we develop and analyze a two node tandem communication network model with feedback for the first node, with an assumption that the arrivals follow homogeneous Poisson process. In this model, the service rates of each transmitter depends on the number of services in the buffer connected it. The model is analyzed using the difference-differential equations and a probability generating function of the number of packets in the buffer. Expressions are derived for performance measures including average number of packets in each buffer, the probability of emptiness of the network, the mean delay in the buffer and in the network, the throughput of the transmitters, and the variance of the number of packets in the buffer.

Performance Evaluation of Three-Node Tandem Communication Network Model with Feedback for First Two nodes Having Non Homogeneous Poisson Arrivals

Tandem Queues are widely used in mathematical modeling of random processes describing the operation of Manufacturing systems , supply chains, Computer and telecommunication networks. In many of the communication systems the arrivals are time dependent and can be characterized by a non homogeneous Poisson process. In this paper we developed and analyzed three nodes connected in tandem Queue with feedback for the first and second nodes assuming that arrivals follow non homogeneous Poisson process. Using the difference-differential equations and a probability generating function of the number of packets in the buffer connected to the transmitter the System is analyzed. The System performance is analysed by deriving expressions for the performance measures of the network like mean content of the buffers, mean delays through put, transmitter utilization with mathematical illustrations. The sensitivity analysis of the model reveals that the non homogeneous Poisson arrivals and dynamic bandwidth allocation strategy can reduce burstness in buffer and improve quality of service.

Simulation Based Performance Comparison of Reactive Routing Protocols in Mobile Ad-Hoc Network Using NS-2

An ad hoc network is a collection of mobile nodes forming an instant network without fixed topology. In such a network, each node acts as both router and host simultaneously, and can move out or join in the network freely. To facilitate communication within the network a routing protocol is used to discover routes between nodes. The main aim of the routing protocol is to have an efficient route establishment between a pair of nodes, so that messages can be delivered in a timely manner. Routing in the MANETs is a challenging task which has led to development of many different routing protocols for MANETs. In this paper, an attempt has been made to compare two well known reactive routing protocols Ad-hoc On demand Distance Vector (AODV) and Dynamic Source Routing (DSR) by using three performance metrics Packet Delivery Ratio, Average End to End Delay and Routing Load. The comparison is done by varying number of sources and for each pause time. These simulations are carried out using the NS-2 network simulator.

Designing Dependable Web Services Security Architecture Solutions

Web Services Security Architectures have three layers, as provided by NIST standard: Web Service Layer, Web Services Framework Layer (.NET or J2EE), and Web Server Layer. In services oriented web services architecture, business processes are executed as a composition of services, which can suffer from vulnerabilities pertaining to secure data access and protecting code of Web Services. The goal of the Web services security architecture is to summary out the details of message-level security from the mainstream business logic, with a focus on Web Service contract design and versioning for SOA. Service oriented web services architectures impose additional analysis complexity as they provide much flexibility and frequent changes with in orchestrated processes and services. In this paper, we discuss about developing dependable solutions for Web Services Security Architectures in terms of Privacy and Trust negotiation. All this research is motivated by Secure Service Oriented Analysis and Design research domain. We initially validate this by a BPEL Editor using GWT for RBAC and Privacy. Finally a real world case study is implemented using J2EE, for validating our approach. Secure Stock Exchange System using Web Services is to automate the stock exchange works, and can help user make the decisions when it comes to investment.