Showing papers in "International Journal of Communication Networks and Distributed Systems in 2013"

Measuring message propagation and social influence on Twitter.com

Abstract: Although extensive studies have been conducted on top of online social networks OSNs, it is not clear how to characterise information propagation and social influence, two types of important but not well defined social behaviour. This paper presents a measurement study of 58 M messages collected from 700 K users on Twitter.com, a popular social medium. We analyse the propagation patterns of general messages and show how breaking news Michael Jackson's death spread through Twitter. Furthermore, we evaluate different social influences by examining their stabilities, assessments, and correlations. This paper addresses the complications and challenges we encounter when measuring message propagation and social influence on OSNs. We believe that our results here provide valuable insights for future OSN research.

Content management in a mobile ad hoc network: beyond opportunistic strategy

Abstract: We study the challenging problem of strategic content placement in a dynamic MANET. Existing content placement techniques cannot cope with such network dynamics since they are designed for fixed networks. Opportunistic caching approaches are insufficient as they do not actively manage contents for certain goals. In this paper, we present a novel content management approach, called LACMA that leverages the location information available to mobile devices via GPS. The main insight behind LACMA is to bind data to geographic location as opposed to network nodes. This location-based strategy decouples the content placement problem from the changing network topology, and allows us to design an optimisation framework even in a dynamic MANET environment. We present key components of LACMA used for strategic content placement and content-location binding through proactive content push. We evaluate LACMA and compare its performance with existing caching schemes and show that LACMA considerably outperforms existing schemes over a wide range of scenarios.

Versatile time-cost algorithm VTCA for scheduling non-preemptive tasks of time critical workflows in cloud computing systems

Abstract: In cloud computing environments, resources and infrastructure are provided as a service over internet on demand. The users are interested in reducing the service cost provided by the cloud service providers. Scheduling tasks of workflows play a vital role in determining performance of cloud computing systems. Workflows have many tasks in it and are interdependent on each other. Time critical workflows comprise of a collection of tasks which should be completed as early as possible so that other workflows get its turn. The budget involved in executing the time critical tasks is very high. The execution cost increases whenever we try to reduce the execution time. In this paper, we propose a method called versatile time-cost algorithm VTCA to schedule time critical workflows with minimum cost. VTCA will schedule the tasks to complete in earliest possible time as well as optimise the cost involved in resource provisioning. The results of experiments conducted using CloudSim simulator show that our scheduling policy minimises the completion time of workflows than other existing algorithms like min-min and fair max-min by 5% to 30% and it also reduces the costs by 5% to 35%.

Detection of distributed denial of service attacks in cloud computing by identifying spoofed IP

Abstract: Cloud computing is a booming field which will be predominating the IT industries soon. Cloud computing is a virtual dynamic version of the present day internet resource access which is static. Cloud computing provides high availability of various large-scale geographically distributed resources for users ranging from small to large-scale on demand. The two key advantages of this model are ease of use and cost effectiveness, i.e., cost as per the usage and maximum resource utilisation. The main issue identified in cloud computing is security. In the specific case of cloud computing systems, the impact of a flooding attack is expected to be amplified drastically as and when the cloud computing operating system notices the high workload on the flooded service, it will start to provide more computational power to cope with the additional workload. The attacker can flood a single, cloud-based address in order to perform a full loss of availability on the intended service. In this paper, the proposed spoofing detection algorithm to detect DDos attacks launched against a server inside a cloud.

A framework for power estimation and reduction in multi-core architectures using basic block approach

Abstract: In recent scenarios, power consumption is critical for battery operated devices. There are wide varieties of implementations of dynamic voltage scaling (DVS) algorithm to reduce energy or power. This paper presents a framework called PERMA, power estimator and reducer for multi-core architectures. The PERMA estimates power consumption and suggests analytical procedure to reduce power consumption at basic block level rather than at region level using clock cycles of instructions for a particular architecture (x86). PERMA estimates execution time for each basic block for various voltage levels and chooses best out of these. Therefore, PERMA evaluates the extent to which the voltage can be varied for various Basic Blocks to reduce power consumption without degrading execution time. Finally, it is tested for matrix multiplication of various sizes. There is an improvement in the execution time up to 33.43% with PERMA and 21.89% without PERMA.

Application-centric recovery algorithm for wireless sensor and actor networks

Abstract: Sustaining actor-actor connectivity is extremely crucial in mission-critical applications of wireless sensor and actor networks where actors have to quickly plan optimal coordinated responses to detected events. This paper presents ACR, a novel hybrid application-centric connectivity restoration algorithm that factors in the application besides efficient resource utilisation while recovering from critical node failures. As a pre-failure planning measure to minimise recovery delay, ACR identifies the actors' primaries that are critical for network connectivity based on localised information and then designates for them backup nodes. The backup nodes are carefully picked to satisfy application concerns such as actor effectiveness. In order to minimise the impact of critical node failure on coverage and connectivity, ACR appoints high degree nodes with overlapped coverage. Upon failure detection, the pre-designated backup pursues controlled and coordinated movement to replace the failed node. We prove the convergence of ACR and analytically derive bounds on its performance. Simulation results further confirm the performance of ACR.

Communication infrastructure planning for wide area measurement systems in power systems

Abstract: Smart grid denotes integration of all elements connected to a power grid with a communication infrastructure. In modern power systems, wide area measurement systems WAMS are such systems that use communication infrastructure to share their data and information. Recently, WAMS have been a new opportunity that contributes power system operators to receive and process the whole information of the system. State estimation is recognised as the basis of WAMS applications since it provides creditable data for other WAMS applications. In this study, we propose a new approach to design communication infrastructures of power systems. The designed communication infrastructure creates routing paths from installed phasor measurement units to the control centre in order to estimate system states. Simulation results confirm that, in a WAMS implementation, the price of secure, reliable and high-speed communication infrastructure of such a WAMS should be taken into account.

From sensing to controlling: the state of the art in ubiquitous crowdsourcing

Abstract: Crowdsourcing systems aim to solve complex tasks by engaging a multitude of humans through mobile and social media and by harnessing their ability to perform specific subtasks and to report the results. Given the rapid increase in the number, size and diversity of ubiquitous crowdsourcing applications across a wide spectrum of domains all around the world, there is a need for a principled way of conceptualising such systems. The first step is the development of a crowdsourcing typology to create a baseline for comparing, evaluating and advancing efforts in this field. For example, crowdsourcing systems need to address a common set of issues to ensure their effectiveness, such as quality control and incentive design. In this paper, we present a thematic overview of the emerging ubiquitous crowdsourcing systems by grouping them based on the task complexity that they support and along key challenges in successfully harvesting expertise of large human networks.

AODV-based technique for quick and secure local recovery from link failures in MANETs

Abstract: Wireless links in MANET may be broken frequently due to nodal mobility and power failures. Such problems make routing protocols, like AODV, inefficient and unreliable. Presently, these problems are solved using local repairing mechanisms at an intermediate node by creating an alternative route to the destination. But it increases routing overhead and unnecessarily consumes MANET resources. Further, if there are no checks on the selection of nodes while creating an alternative route, there is every possibility that a malicious node may take its place in the path. In this paper, we propose a technique which does a quick local recovery from the link failures and also avoids misbehaving nodes to creep in the path. The combined technique improves performances and also consumes less energy of nodes in MANET. Performance analysis and simulation results show that our proposed technique achieves significant performance improvement over existing AODV-based techniques.

Augmented materials: spatially embodied sensor networks

Abstract: Wireless sensor networks are increasingly common in medical, environmental monitoring, precision agriculture, smart home monitoring, and other applications. Most wireless sensor networks operate in air or liquid media: in this paper we are concerned with the design and implementation of sensor networks embedded into solid materials, thus placing sensing and processing capabilities into the fabric of built objects and environments. We introduce the concept and its component challenges, and present some early work demonstrating the feasibility of such 'augmented' materials to provide semantically rich sensing and response.

Distributed multi-agent communication system based on dynamic ontology mapping

Abstract: Communication is the most important feature for meaningful interaction among agents in distributed multi-agent systems. Communication enables agent's interaction to achieve their goals. Agent communication languages provide a standard in the protocol and language used in the communication, but cannot provide a standard in ontology, because ontology depends on the subject and concept of the communication. This lack of standardisation is known as interoperability problem. In order to obtain semantic interoperability, agents need to agree on the basis of different ontologies. In this paper, a communication layer is proposed to outline the communication between agents, multiplatform communication system (MPCS) architecture is proposed to provide a highly flexible and scalable system. In addition a dynamic ontology mapping system for agent communication (DOMAC) is proposed based on different mapping approaches.

An energy aware enhanced AODV routing protocol in MANET

Abstract: As the growth of multimedia communication in mobile ad hoc networks MANETs, every node needs to conserve its power since most nodes are powered by a battery source. Mobile ad hoc networking is a challenging task due to the lack of resources in the network as well as the frequent changes in network topology. Although lots of research has been done on supporting QoS in the internet and other networks, but they are not suitable for mobile ad hoc networks and still QoS support for such networks remains an open problem. In this paper, we propose that the enhanced ad hoc on-demand distance vector AODV routing protocol which is modified to improve the networks lifetime in mobile ad hoc network MANET. The new scheme has been proposed for achieving QoS in terms of packet delivery, better power management and stable routes. The proposed scheme has been incorporated using AODV protocol.

Network lifetime analytical model for node-disjoint multipath routing in wireless sensor networks

Abstract: The objective of every sensor node in a sensor network is to send the sensed data in the phenomena to a sink node. The network lifetime is maximal, when the energy consumption of each node is uniform. Many routing protocols select an optimal path to increase the network lifetime in sensor networks. The energy of the nodes along this optimal path is consumed more, causing their early death. In the multipath routing, data traffic is distributed among the multiple paths, instead of a single optimal path. This work proposes a theoretical frame work to study the node-disjoint multipath wireless sensor network reliability. With higher reliability, higher network lifetime can be achieved. Simulation results show that when the data is transmitted through multiple paths with different data rates, the network lifetime increases. The node criticality factor enhances the network lifetime analysis effectively.

Formation and interaction patterns in social crowdsourcing environments

Abstract: Over the past years, the web has transformed from a pool of statically linked information to a people-centric web. Various web-based tools and social services have become available enabling people to communicate, coordinate, and collaborate in a distributed manner. In this work, we consider social crowdsourcing environments that are based on the capabilities of human-provided services HPS and software-based services SBS. Unlike traditional crowdsourcing platforms, we consider collaborative environments where people and software services jointly perform tasks. We propose formation and interaction patterns that are based on social principles. The idea of our social crowdsourcing approach is that interactions emerge dynamically at runtime based on social preferences among actors. The evolution of interactions is guided by a monitoring and control feedback cycle to recommend competitive compositions and to adjust interaction behaviour. Here we present fundamental formation patterns including link mesh and broker-based formations. We discuss the prototype implementation of our service-oriented crowdsourcing framework.

SAVEUS: SAving Victims in Earthquakes through Unified Systems

Abstract: Natural disasters such as earthquakes damage the systems that are designed to confine the damage they cause. Many schemes have been suggested to minimise the damage but there is no single scheme that is equally effective in all types of natural disasters. Our hypothesis is that if relevant information about the event during and after it ends is gathered and disseminated in a timely manner, then we can significantly minimise the damage. We envision a system to deal with earthquakes in real-time that is called SAVEUS and has three main innovative components. The first component, called the rescue social network RSN, gathers useful information from the general public and first responders and deposits it to the second component called agile knowledge base AKB that stores and processes information. The third component is called the rescue sensor network RSeN that discovers victims survivors and saves the information in the AKB.

Analysis of a refined model for the IEEE 802.11 distributed coordination function

Abstract: As the IEEE 802.11 standard WLANs become more and more ubiquitous, a number of studies on the saturation throughput analysis for the distributed coordination function have been presented. In order to reconcile previous differences, and to conform to the actual IEEE 802.11 standard, a new backoff decrement model which takes into consideration anomalous slots has already been proposed, which is rigorously analysed in this paper. Moreover, we present a rough outline of a decision-making framework for finding a policy for a controller to select optimal backoff counter values at different backoff stages.

On user perception of safety in online social networks

Abstract: Today, many people share personal information through online social networks, and thus they are exposed to the risk to get their accounts compromised, with consequences for their professional and private lives It is observed that users tend to shortcut labourious security measures, which alleges that their perception of their safety on the social network deviates from the real situation We investigate how users of social networks perceive safety and how they contribute to it First, we examine the question how user perception of safety is affected negatively by increased login response times To this end, we studied teenage users of the online social network Facebook Second, in order to find out to which extent users are aware of the risks associated with weak passwords, a survey about password complexity in online social networks was conducted Indeed, we observe differences in password complexity between teenagers with different levels of technical education

BeesAnts: a new nature-inspired routing algorithm

Abstract: In this paper, we have introduced a new multi-agent nature-inspired routing algorithm. The algorithm is referred to as the BeesAnts algorithm. It is a combination of the ant colony-based routing algorithm (ARA) and the BeeHive-based routing algorithm. The proposed routing algorithm works effectively on networks consisting of two parts; one is a fixed network and the other is a mobile ad hoc network (MANET). It applies the ARA routing algorithm on the mobile part and the BeeHive routing algorithm on the fixed part. The experimental results and the statistical analysis have demonstrated that the BeesAnts routing algorithm outperforms its ancestor, the ARA routing algorithm, in terms of the propagation delay, the queue delay, and the number of hops.

Effective use of cloud computing in education: education as a service

Abstract: Cloud computing via its dynamic scalability is carving a new paradigm for virtual resources as well as services across the internet and beyond. It is likely to have a disruptive impact on most of the emerging sectors. Education is one such sector and is ripe for leveraging the offerings of cloud computing. Cloud computing is capable of delivering low cost, flexible, ubiquitous and on-demand educational services. In this paper, first the cloud computing infrastructure is reviewed. This is followed by the development of a comprehensive theory about online education and applicability of cloud computing in education. Post these preliminary discussions, models for utilising and adopting offerings of cloud computing in the field of education are proposed and future areas of research are identified.

ESF: an efficient security framework for wireless sensor network

Abstract: A wireless sensor network WSN consists of a large number of resource constrained sensor nodes, usually deployed in hostile environments, where they face a variety of malicious attacks. To address the security vulnerabilities in WSN, this paper proposes an efficient security framework ESF, which comprises of two security building blocks. The first one security building block is to establish key between the sending and receiving nodes while other component provides confidentiality and integrity of data. Owing to the limited resources available with the sensor nodes, ESF avoids intensive computations like public key cryptography and encryption mechanisms. Analysis of ESF shows that the framework provides a secure environment and resistant against the wireless threats using simple bit-wise operations and cryptographic hash functions.

A cost effective cloud data centre capacity planning method based on modality cost analysis

Abstract: In resource provisioning for data centres, an important issue is how resources may be allocated to an application to guarantee service level agreements SLAs Resource provisioning is usually guided by intuitive or heuristic expectation of performance Such methodology, however, usually leads to more resources than necessary A quantitative performance estimate may guide the provider in making informed allocations, so that acceptable SLAs may be provided in a cost-effective manner In this work, we looked at breaking the application into isolated modalities modality is a scenario in which an application is used and measuring resource cost per modality When breaking the application into modalities, resource cost is assessed in isolation Results are then aggregated to estimate the overall resource provisioning requirements A validation tool is used to simulate the load and validate the assumptions This was applied to a commercially available solution and validated in a data centre setting

Dynamic negotiation of cloud computing services in market-oriented environments

Abstract: An aspiring vision of cloud computing is that it will facilitate the realisation of computing as a fifth utility. Previous research has shown that inadequate support for dynamic negotiation of SLAs is a major obstacle preventing the continued growth and ubiquity of cloud computing frameworks. This paper proposes adoption of an agent-based communication protocol to coordinate a dynamic negotiation process between trading parties within a cloud computing market-oriented environment. The motivation of this research proposal is that adoption of such a technique would have profound implications for the pay-for-use model encapsulated within cloud computing service provision. The paper additionally proposes the realisation of agent-based virtual communities of practice amongst consumers, enabling them to become better informed regarding the service quality of cloud computing providers. The paper appraises the benefits and repercussions of the proposed strategy for both service providers and end users through the construction of a simulation test bed.

Minimalist security and privacy schemes based on enhanced AES for integrated WISP sensor networks

Abstract: Extensive development has yielded the improved version of the radio frequency identification RFID called the wireless identification sensing platform WISP. Recent research suggests the combined system of integrated RFID and wireless sensor network WSN used for coupling the virtual and physical world, bridging the gap between WSN and RFID. The possibility of having an integrated WISP sensor network might be a starting point for the new future smart system's application. And yet, in every system there will be sensitive data that requires various degree of data encryption. Given the steep design challenge and the limited resources provided on both WSN and WISP's platforms, we can foresee that the design trend has to be memory and hardware efficient. In this paper, we present a minimalist approach to securely encrypt, authenticate and exchange secret keys with a minimal instruction set computer MISC processor based on the AES algorithm, termed the enhanced AES NAES processor.

A time-evolution model for the privacy degree of information disseminated in online social networks

Abstract: People tend to share private information with their friends on online social networks OSNs. The common position is that the shared information eventually reaches all users of the network since OSNs exhibit the small-world property. However, dissemination of private information in an OSN exhibits a set of factors that need to be accounted for in order to create more realistic models of the evolution of the privacy degree of information disseminated in an OSN. Among these factors are relationship strength between communicating users, influence of neighbours i.e., friends, users' adoption of new information, change of information, and dynamics of the structure of OSNs. This paper proposes a time series model for measuring the privacy of information disseminated in an OSN using the factors listed above. It shows through simulating the dissemination of private information in an OSN that the privacy of information does not vanish, but in most cases declines to a saturation level related to the information dissemination factors. The results also show how likely a user can get the information when the factors are accounted for.

Self-organised localisation in indoor environments using the ALF framework

Abstract: We present and discuss the autonomous localisation framework ALF, a self-organising indoor localisation environment. Location awareness is an important property for a growing number of applications. GPS is frequently used to provide this information in outdoor environments, but this is not applicable for indoor applications. There have been many approaches to solve the localisation problem for those GPS-denied scenarios. However, many of them are limited to certain hardware restrictions or do not provide robust self-localisation in dynamic real world application. ALF is a complete and modular framework based on minimal hardware requirements. The system is not only capable to deploying itself autonomously in unknown environments and offering position information among the participants, but it also supports accurate real-time localisation to customers. The concepts allows to remove or to add features e.g., the heading of nodes or certain real-time capabilities as the scenario demands or the even the used hardware changes. The awareness and handling of measurement errors, especially in non-line of sight NLOS cases, is an essential criterion for a real world application.

Real-time push middleware and mobile application for electric vehicle smart charging and aggregation

Abstract: This paper presents a real-time push middleware and mobile application for data and multimedia content delivery to enable electric vehicle smart charging and aggregation. Intelligent aggregation and charge scheduling software can leverage the battery capacity of an EV to level peak loads by delaying or throttling charging during peak loads, 'valley fill' during off-peak times, and contribute to demand response and spinning reserves by sending electricity into the grid. EV users are updated on the status of their vehicle and may set their charge parameters via web or native mobile application. Facility and utility operators can monitor and control garage and microgrid status through a separate web or mobile application. The content to facilitate aggregated smart charging and monitoring may come from a variety of sources including web servers, ftp servers, Bluetooth or Zigbee or other protocol sensors, and local or remote databases. The middleware will accept content upload and database storage, securely provide content to outside entities, match content to user subscriptions, use user context including connection speed, device type, and location to deliver appropriately formatted content, and provide a reliable mechanism for push content delivery to a multitude of devices including mobile phones and tablet.

System-level fault diagnosis in fixed topology mobile ad hoc networks

Abstract: In this paper, we present a protocol for diagnosing faulty mobiles using asymmetric comparison-based approach that exploits the shared nature of communication in mobile ad hoc networks MANETs. The protocol is divided into three main phases: a Testing_Responding phase, a Gathering phase and a Building_Disseminating phase. During the Testing_Responding phase, units can test their neighbours and also respond to the received test messages. In the Gathering phase, units collect and compare the responses from their neighbours to generate local diagnosis views. A spanning tree is constructed in Building_Disseminating phase that covers all fault free active mobiles in the system and is used to exchange the local diagnosis information those are compounded to generate a global diagnosis view of the whole system. We consider both hard and soft faulted mobile hosts. The proposed protocol is shown to have less communication complexity and hence well suited for energy constrained MANETs.

An efficient event delivery scheme in mobile ad hoc communities

Abstract: Delivering events and advertisements to interested individuals is an important issue for mobile ad hoc communities. Providing a feasible solution to event delivery in highly dynamic and error prone mobile ad hoc environments is a challenging problem due to the inherent unreliable and unstable nature of mobile ad hoc networks. This paper proposes a novel semantics-based publish/subscribe scheme for efficient event and advertisement delivery in large-scale mobile ad hoc communities. In our proposed publish/subscribe system, mobile nodes are organised into groups and a compact semantics-based indexing is deployed in the groups. Efficient intra-and inter-group routings are proposed to facilitate efficient propagation of event notifications. The effectiveness of the system is demonstrated through a comprehensive set of simulation studies.

Discrete-time modelling for performance analysis and optimisation of uplink traffic in IEEE 802.16 networks

Abstract: This paper analyses the performance and optimisation of uplink traffic in IEEE 802.16 networks of the different service classes. IEEE 802.16 standard suite is currently the latest broadband wireless access reservation-based bandwidth allocation mechanism. An 802.16 wireless service provides a communications path between a subscriber station SS and a base station BS with uplink and downlink directions. A SS has to be polled to request bandwidth reservation before transmits uplink data to a BS with an appropriate QoS. A discrete-time Geo/G/1 queuing model is utilised to investigate the performance of uplink traffic in IEEE 802.16 networks using the imbedded Markov chain technique. Some performance measures and illustrative numerical results have also been discussed. A cost model is developed to determine the optimal values of arrival and service rate at a minimum cost. The genetic algorithm is employed to search the optimal values of arrival and service parameters for the system.

Cryptography with fast point multiplication by using ASCII codes and its implementation

Abstract: This paper describes the point multiplication through addition-subtraction method and its implementation through MATLAB to speed up the operations in elliptic curve cryptography ECC with ASCII codes under limited hardware resources. To further decrease the computation time, we employed the non-adjacent form of a binary sequence to decrease the total number of additions in ECC encryption/decryption. This paper implements ASCII code table for convenient manipulation of characters, and addition-subtraction method for point multiplication with less time and space complexity with its implementation in MATLAB. We can fully use the idle time of hardware resources by relaxing the data dependency on those arithmetic operations performed to accomplish the point multiplication. As a result, hardware utilisation increases. ECC is the most applicable and suitable algorithm for mobile devices due to its compact shape and size.