Mohamad Nazim Jambli

Performance evaluation of AODV routing protocol for mobile wireless sensor network

Topology change is the main factor that affects the network life time of Wireless Sensor Network (WSN) applications. In static WSN, the topology change is often caused by node failure which is due to energy depletion. However, in the Mobile WSN (MWSN), the main reason of the topology change is caused by the node movement. Since the mobile sensor nodes are limited in power supply and have a low radio frequency coverage, they are easily losing their connection with neighbours, and have difficulties updating their routing tables. The switching process from one coverage area to another consumes more energy that related to transmitting and receiving association packets. Using Ad hoc On-Demand Distance Vector (AODV) routing protocol in MWSN application shows degradation in network performance due to high density and speed of mobile nodes. In this paper, through extensive simulation we evaluated the capability of AODV on how far it can react to network topology change in MWSN. We investigated the performance metrics namely packet loss and energy consumption of mobile nodes with various speed, density and route update interval (RUI). Our performance study demonstrates that by applying the existing AODV in MWSN, the results show a high percentage of packet loss and the reduction in total network energy consumption of mobile nodes if RUI is getting longer due to serious broken link caused by nodes movement. We also identify some key research problems that need to be addressed for successful implementation of AODV in MWSN.

Transmission power control in mobile wireless sensor networks: Simulation-based approach

Saving energy is a very critical issue in wireless sensor networks (WSNs) because sensor nodes have a severe resource constraints such as lack of processing power and limited in power supply. Since the communication is the most energy consuming activities in WSNs, the power use for transmission or reception of packet should be managed properly. Transmission power control (TPC) technique is one of the techniques to reduce energy consumption which has been widely studied in mobile ad-hoc networks (MANETs). This technique is implemented by adjusting the transmission power in communication between nodes. However, as mobile wireless sensor networks (MWSNs) applications emerge, the unique characteristics of this network such as severe resource constraints and frequent topology change suggest that TPC might be useful to reduce energy consumption in MWSN. Therefore, we investigate the impact of TPC on Ad hoc On-Demand Distance Vector (AODV) routing protocol for MWSNs. AODV is used as a medium of communication to assist the investigation of the effects of TPC in multihop communication in MWSNs. The simulation results show that the implementation of TPC technique has some impact on MWSNs in respect to transmission energy consumption and transmission power level required at low node mobility.

Enhancement of AODV routing protocol in MASNETs

The rapid development of wireless communication technologies and portable mobile devices such as laptops, PDAs, smart phones and wireless sensors brings the best out of mobile computing particularly mobile ad-hoc and sensor networks. Nowadays, most of researchers working on Wireless Sensor Networks (WSNs) focus on Mobile Ad-hoc and Sensor Networks (MASNETs) due to their wide range of potential applications ranging from underwater monitoring to search and rescue mobile robotics applications. In this research work, through extensive simulation, we have evaluated the capability of Ad-hoc On Demand Distance Vector (AODV) routing protocol on how far it can react to different mobility duration of mobile nodes in MASNETs. The performance of AODV is investigated in terms of the average percentage of packet loss and energy consumption. The initial performance study demonstrates that the performance of AODV is signicantly decreased in mobile environment due to the frequent topology change in MASNETs. Therefore, in order to enhance the performance of AODV in MASNETs, the new routing algorithm based on the estimated distance is proposed to replace the hop count for the selection of next node during the packet transmission. The estimated distance is computed based on the Received Signal Strength Indicator (RSSI) values that are collected during the communication between the sensor nodes. The performance of the proposed solution is also further evaluated and compared with the existing AODV routing protocol in term of their energy consumption and percentage of packet loss. Our study demonstrates that the proposed solution outperform the existing AODV in MASNETs.

Evaluation of clustering and multi-hop routing protocols in Mobile Ad-hoc Sensor Networks

Mobile ad-hoc sensor networks (MASNETs) have promised a wide variety of applications such as military sensor networks to detect and gain as much as possible about enemy movements and explosions. Most of these applications can be deployed either in static or mobile environment. In static WSNs, the change of sensor nodes topology is normally caused by node failure which is due to energy depletion. However, in MASNETs, the main reason of the topology change is caused by the node movement. Since the sensor nodes are limited in power supply and have a low radio frequency coverage, they are easily losing their connection with neighbours and difficult to transmit their packets towards sink node. The reconnection process from one node to another node consumes more energy that related to control packets. One of the techniques to conserve more energy is through topology management using clustering network. A HEED (Hybrid, Energy-Efficient, Distributed) is one of the clustering algorithm for sensor networks. In HEED, a node is elected to become a cluster head based on its residual energy and its communication cost in its neighbourhood. HEED clusters the network in a constant number of iterations, elects cluster heads that are well-distributed in the network, and incurs low message and communication overhead. In this research work, through extensive simulation we evaluated the capability of HEED on how far it can react to network topology change in MASNETs by comparing its performance with Surge multi-hop routing protocol in both static and mobile environment. We investigated the performance of both HEED and Surge in terms of the average percentage of packet loss and the average total energy consumption with various simulation times. From the detailed simulation results and analysis, HEED performs better than Surge in term of energy consumption in static network, but not performs as expected in mobile environment.

Neighbor Selection Protocol for Heterogeneous Information Dissemination in Opportunistic Networks

In Opportunistic Networks, information forwarding takes place when nodes are in communication range. Absence of knowledge on network topology prior information forwarding poses a compelling challenge in Opportunistic Networks. In these networks, disconnected mobile peers use mobility to opportunistically and dynamically connect to each other in order to disseminate heterogeneous information towards the intended destination. Flooding disseminates information to all nodes in range. Hence, it achieves high delivery performance. However, this form of dissemination congests the network and create considerable amount of network overheads. In this paper, a social-based neighbor selection protocol is proposed to enhance the heterogeneous information dissemination through peer-to-peer interaction in Opportunistic Networks. Neighbor is selected based on social structure formulated by Frequency in Range, Frequency of Interaction metrics and Heterogeneity of information. A high valued metric peer from the list of candidate peers is selected as potential forwarder to disseminate information. The delivery performance impact of our protocol on information dissemination was investigated and has been analyzed in customized simulation tool. Experimental results showed that, the proposed neighbor selection protocol achieved delivery performance close to random selection in flooding and reduced 88.25% push overhead incurred during dissemination.

Performance evaluation of AODV in MASNETs: Study on different simulators

Nowadays, most of researchers working on Wireless Sensor Networks (WSNs) focus on Mobile Ad-hoc and Sensor Networks (MASNETs) due to their wide range of potential applications ranging from underwater monitoring to search and rescue mobile robotics applications. Most of these applications are deployed in remote and unattended areas. Since MASNETs are energy-constrained networks which have a low radio frequency coverage, their network topologies are frequently change due to mobile sensor nodes. In this paper, through extensive simulation of two different simulators namely Avrora and Castalia, we evaluated the capability of Ad-hoc On Demand Distance Vector (AODV) routing protocol on how far it can react to different speed and density of mobile nodes in MASNETs. We investigated the performance of AODV in terms of the average percentage of packet loss with the various speed and density of mobile nodes. Our performance study demonstrates that both simulators show the performance of AODV is significantly decreased in mobile environment due to the frequent topology change in MASNETs.

The study of AODV routing protocol in Vehicular Ad-hoc Sensor Networks

In VASNETs, each vehicle carries an intelligent node, which sense the real phenomena and collects the required data. There are many routing protocols that have been proposed and assessed the efficiency of VANETs. However, there are only several research about performance evaluation of routing protocol in VASNETs. In order to fill that gap, in this research we have undergo the performance evaluation of AODV routing protocol in VASNETs. The experiment was setup in order to investigate the effect of different simulation area towards increasing velocity and number of mobile nodes. The tools that been used for this purpose is AVRORA simulation tool. Based on the simulation results obtained, the performance of AODV is analyzed and compared in different sizes of simulation area. The simulation results show the significant different in the variation of simulation area in term of the percentage of packet loss in VASNET.

Applying SOFL to construct requirements specification for examination monitoring system

SOFL approach to the construction of the formal specifications has been proposed and applied in information systems, but its effectiveness and applicability have not been demonstrated aggressively. In this paper, we describe an application of the SOFL approach to the construction of a specification during requirements analysis. This approach requires two steps: informal and semi-formal steps. In order to describe on how this approach can be applied to capture requirements using SOFL easily, we use a case study to develop an examination monitoring system for construct abstract requirements. This case study demonstrates the suitability of SOFL to capture detail requirements and provides us with an insight into the knowledge of how SOFL approach can be effectively supported.

Evaluation of FCV and FCM clustering algorithms in cluster-based compound selection

In the last few years, a number of available screening compounds has been growing rapidly due to the recent developments of high-throughput screening in drug discovery. Chemical vendors provide millions of compounds for drug lead identification; however, these compounds are highly redundant. Clustering method that groups similar compounds into families, can be used to analyze such redundancy. One of most used clustering method is cluster-based compound selection, which involves subdividing a set of compounds into clusters and choosing one compound or a small number of compounds from each cluster. However, little research has been done on overlapping method fuzzy c-means (FCM) and fuzzy c-varieties (FCV) clustering algorithms in compound selection research. Therefore, these two clustering algorithms are implemented and the performance is analyzed based on the effectiveness of the clustering results in terms of mean intercluster molecular dissimilarity (MIMDS) where these results are compared with one another. The analysis shows that in terms of MIMDS, the FCV is better than FCM because it clearly shown the uniform results compare to FCM clustering algorithm.