Asri Ngadi

Symbiotic Organism Search optimization based task scheduling in cloud computing environment

Efficient task scheduling is one of the major steps for effectively harnessing the potential of cloud computing. In cloud computing, a number of tasks may need to be scheduled on different virtual machines in order to minimize makespan and increase system utilization. Task scheduling problem is NP-complete, hence finding an exact solution is intractable especially for large task sizes. This paper presents a Discrete Symbiotic Organism Search (DSOS) algorithm for optimal scheduling of tasks on cloud resources. Symbiotic Organism Search (SOS) is a newly developed metaheuristic optimization technique for solving numerical optimization problems. SOS mimics the symbiotic relationships (mutualism, commensalism, and parasitism) exhibited by organisms in an ecosystem. Simulation results revealed that DSOS outperforms Particle Swarm Optimization (PSO) which is one of the most popular heuristic optimization techniques used for task scheduling problems. DSOS converges faster when the search gets larger which makes it suitable for large-scale scheduling problems. Analysis of the proposed method conducted using t -test showed that DSOS performance is significantly better than that of PSO particularly for large search space. Discrete Symbiotic Organism Search algorithm for task scheduling is proposed.The proposed algorithm has better ability to exploit best solution regions than PSO.The proposed method has global ability in terms of exploring optimal solution points.The proposed algorithm performs significantly better than PSO for large search spaces.

A taxonomy of cross layer routing metrics for wireless mesh networks

Multi-hop, multi-channel, and multi-radio wireless mesh networks (WMNs) are emerging as promising field of wireless technology with self-organizing and self-healing features for internet and real time applications, i.e., VoIP and Video over IP. Interoperability feature of WMNs have made them to integrate easily with other network technologies like wired networks, WiFi, WiMax, MANETs, and cellular networks. WMNs are gaining popularity due to their high network throughput which highly depends on the routing procedures. Routing algorithms like optimized link state routing protocol and dynamic source routing make efficient routing decisions on the basis of routing metrics which actually predict the cost of link quality. Most of the routing protocols and routing metrics implemented in WMNs are actually designed for mobile ad hoc networks (MANETs). Since WMNs have different characteristics and limitations as compared to MANETs, so the routing metrics design for MANETs do not perform well in WMNs. Furthermore, quality of service (QoS) and throughput of the network in WMNs can be enhanced by using cross layer routing approach and by deploying multi-channel multi-radio (MCMR) scenarios in each relay node. This article discusses a design taxonomy, limitations and qualitative comparison of existing routing metrics for QoS in MCMR WMNs with respect to routing parameters, i.e., transmission rate, inter-flow interference, intra-flow interference, congestion, and channel diversity. Moreover, our taxonomy also opens the door up for new research areas in the design of cross layer routing metrics for MCMR radio WMNs for high throughput IP connectivity.

Fuzzy-assisted social-based routing for urban vehicular environments

In the autonomous environment of Vehicular Ad hoc NETwork (VANET), vehicles randomly move with high speed and rely on each other for successful data transmission process. The routing can be difficult or impossible to predict in such intermittent vehicles connectivity and highly dynamic topology. The existing routing solutions do not consider the knowledge that behaviour patterns exist in real-time urban vehicular networks. In this article, we propose a fuzzy-assisted social-based routing (FAST) protocol that takes the advantage of social behaviour of humans on the road to make optimal and secure routing decisions. FAST uses prior global knowledge of real-time vehicular traffic for packet routing from the source to the destination. In FAST, fuzzy inference system leverages friendship mechanism to make critical decisions at intersections which is based on prior global knowledge of real-time vehicular traffic information. The simulation results in urban vehicular environment for with and without obstacles scenario show that the FAST performs best in terms of packet delivery ratio with upto 32% increase, average delay 80% decrease, and hops count 50% decrease compared to the state of the art VANET routing solutions.

An Efficient Next Hop Selection Algorithm for Multi-Hop Body Area Networks.

Body Area Networks (BANs) consist of various sensors which gather patient’s vital signs and deliver them to doctors. One of the most significant challenges faced, is the design of an energy-efficient next hop selection algorithm to satisfy Quality of Service (QoS) requirements for different healthcare applications. In this paper, a novel efficient next hop selection algorithm is proposed in multi-hop BANs. This algorithm uses the minimum hop count and a link cost function jointly in each node to choose the best next hop node. The link cost function includes the residual energy, free buffer size, and the link reliability of the neighboring nodes, which is used to balance the energy consumption and to satisfy QoS requirements in terms of end to end delay and reliability. Extensive simulation experiments were performed to evaluate the efficiency of the proposed algorithm using the NS-2 simulator. Simulation results show that our proposed algorithm provides significant improvement in terms of energy consumption, number of packets forwarded, end to end delay and packet delivery ratio compared to the existing routing protocol.

Quantifying the severity of blackhole attack in wireless mobile Adhoc networks

Blackhole attack is one of the severe attacks in MANET routing protocols. Generation of this attack is simple, which does not require specific tools or sophisticated attack techniques. However, this attack seriously corrupts the routing tables of nodes in the network. Even worse, the attack could increase the chances of losing confidential data and deny network services. Many researchers have proposed a variety of solutions to prevent this Conventional Blackhole Attack (CBA). Unfortunately, none of them has measured the severity of this attack. Filling gaps in measuring the severity of this attack, this research proposes a new security metrics, namely Corruption Routing Table (CRT), Compromising Relay Node (CRN) and Compromising Originator Node (CON). In addition, this research also introduces a new blackhole attack, namely Hybrid Black Hole Attack (HBHA) with two variants — Independent and Cooperative HBHAs. The proposed metrics proved effective in measuring the severity of both CBA and HBHAs. Simulation using Java in Time Simulator/Scalable Wireless Adhoc Network Simulator (JiST/SWANS) showed that Independent HBHA is the most severe attack compared to Cooperative HBHA and CBA. In addition, Cooperative HBHA is the most efficient attack than Independent HBHA and CBA.

A review of blackhole attack in mobile adhoc network

Mobile ad hoc network (MANET) is used in a wide range of application from civilian usage to military battlefield communications. Using multi-hop communication model, a source node can directly communicate with the destination node without infrastructure. Unfortunately, this feature causes the network vulnerable to various attacks. Security preventions implemented in the traditional wired network are unsuitable for MANET. This paper studies several types of attacks, and then discusses one of the most severe attack in the network, blackhole attack. Furthermore, recent efforts for preventing the blackhole attack are comprehensively discussed. Study of literature indicates that the prevention of the blackhole attack can be categorized into three groups, i.e., Protection based on Cryptography, Protocol Modification, and Intrusion Detection and Counter Measure.

Development and validation of a Database Forensic Metamodel (DBFM)

Database Forensics (DBF) is a widespread area of knowledge. It has many complex features and is well known amongst database investigators and practitioners. Several models and frameworks have been created specifically to allow knowledge-sharing and effective DBF activities. However, these are often narrow in focus and address specified database incident types. We have analysed 60 such models in an attempt to uncover how numerous DBF activities are really public even when the actions vary. We then generate a unified abstract view of DBF in the form of a metamodel. We identified, extracted, and proposed a common concept and reconciled concept definitions to propose a metamodel. We have applied a metamodelling process to guarantee that this metamodel is comprehensive and consistent.

Towards adapting metamodelling technique for database forensics investigation domain

Threats which come from database insiders or database outsiders have formed a big challenge to the protection of integrity and confidentiality in many database systems. To overcome this situation a new domain called a Database Forensic (DBF) has been introduced to specifically investigate these dynamic threats which have posed many problems in Database Management Systems (DBMS) of many organizations. DBF is a process to identify, collect, preserve, analyse, reconstruct and document all digital evidences caused by this challenge. However, until today, this domain is still lacks having a standard and generic knowledge base for its forensic investigation methods / tools due to many issues and challenges in its complex processes. Therefore, this paper will reveal an approach adapted from a software engineering domain called metamodelling which will unify these DBF complex knowledge processes into an artifact, a metamodel (DBF Metamodel). In future, the DBF Metamodel could benefit many DBF investigation users such as database investigators, stockholders, and other forensic teams in offering various possible solutions for their problem domain.

A survey on TCP CUBIC variant regarding performance

CUBIC is one of the most popular version of TCP being used by many flavours of Linux now a days. CUBIC [6] is an enhanced version of BIC TCP (Binary Increase Congestion Transmission Control Protocol) ??. To enhance the scalability of TCP in long distance network scenarios, CUBIC modified the linear window growth function of standard TCP to cubic [6] function. During communication, CUBIC decreases the size of congestion windows (cwnd) at Saturation-States and increases its size instantly at Stable-States. CUBIC protocol keeps the window-increase- rate independent of RTT, which helps the protocol TCP friendly in short and long RTTs. When the CUBIC window-growth-function is slower than standard TCP, CUBIC [6] behaves like standard TCP in order to provide fairness to standard TCP. In this Paper, CUBIC performance evaluation is done by Network Simulator-2 experiments. As this is a survey paper, performance analysis of other TCP versions is also discussed.

Interference Nomenclature in Wireless Mesh Networks

The Quality of Service of Multi-Channel Multi-Radio Wireless Mesh Networks is adversely affected by the complex behavior of interference patterns present between the sender and receiver of a link. This behavior is usually captured using wireless channel interference models. The accuracy of the interference model is highly dependent on the interaction of the Carrier Sense Multiple Access with Collision Avoidance Medium Access Control (CSMA/CA MAC) protocol based on the geometric location of the sender and receiver of the link. Therefore, this paper presents a nomenclature of interference modeling schemes available in Wireless Mesh Network (WMN) literature with respect to the geometric location of the sender and receiver of a link. The behavior and limitations of each model are analyzed with the help of empirical examples. The results indicate that Garetto’s model of interfering links is the best choice to model wireless channel interference in WMNs. In addition, this study provides an interference analysis of Garetto’s model for the two link case by computing the conditional packet loss probability of each class of interfering link. The probability analysis concluded that the links with disconnected senders are highly interfering compared to sender connected links. Further, the analysis will assist researchers and engineers in relay node placement, capacity analysis, channel assignment, and topology control schemes in the WMN.