The impact of data aggregation on the performance of wireless sensor networks

With the increasing need for different energy saving mechanisms in Wireless Sensor Networks (WSNs), data aggregation techniques for reducing the number of data transmissions by eliminating redundant information have been studied as a significant research problem. These studies have shown that data aggregation in WSNs may produce various trade‐offs among some network related performance metrics such as energy, latency, accuracy, fault‐tolerance and security. In this paper, we investigate the impact of data aggregation on these networking metrics by surveying the existing data aggregation protocols in WSNs. Our aim is twofold: First, providing a comprehensive summary and comparison of the existing data aggregation techniques with respect to different networking metrics. Second, pointing out both the possible future research issues and the need for collaboration between data management and networking research communities working on data aggregation in WSNs. Copyright © 2006 John Wiley & Sons, Ltd.     

The ARGOS campaign: Evaluation of video analysis and indexing tools

The benchmarking of various methods of video analysis and indexing has become a research problem per se. While a lot of effort nowadays is devoted to organization of evaluation campaigns both on international, such as TREC Video and national levels, an in-depth analysis of the performance of the methods still remains an open issue. Several aspects in the evaluation of methods have to be addressed: how to design a benchmarking corpus in order to cover a sufficiently wide range of applications, what are the tasks to address, what are the most relevant evaluation metrics. The Argos evaluation campaign supported by the French Techno-Vision program aimed at developing resources for a benchmarking of video content analysis and indexing methods. The paper describes the type of tasks evaluated, the way the content set has been produced, metrics and tools developed for the evaluations and some of the results obtained at the end of the first phase. Perspectives based on current works will be given to conclude this paper.     

Characterizing user‐perceived impairment events using end‐to‐end measurements

Measures of quality of service (QoS) must correlate to end‐user experience. For multimedia services, these metrics should focus on the phenomena that are observable by the end‐user. Metrics such as delay and loss may have little direct meaning to the end‐user because knowledge of specific coding and/or adaptive techniques is required to translate delay and loss to the user‐perceived performance. Impairment events, as defined in this paper, are observable by the end‐users independent of coding, adaptive playout or packet loss concealment techniques employed by their multimedia applications. Time between impairments and duration of impairments are metrics that are easily understandable by a network user. Methods to detect these impairment events using end‐to‐end measurements are developed here. In addition, techniques to identify Layer 2 route changes and congestion events using end‐to‐end measurements are also developed. These are useful in determining what caused the impairments. End‐to‐end measurements were conducted for about 26 days on 9 different node pairs to evaluate the developed techniques. Impairments occurred at a high rate on the two paths on which congestion events were detected. On these two paths, congestion occurred for 6–8 hours during the day on weekdays. Impairments caused by route changes were rare but lasted for several minutes. Copyright © 2005 John Wiley & Sons, Ltd.     

A survey on packet size optimization for terrestrial,underwater, underground,and body area sensor networks

Packet size optimization is a critical issue in wireless sensor networks (WSNs) for improving many performance metrics (eg, network lifetime, delay, throughput, and reliability). In WSNs, longer packets may experience higher loss rates due to harsh channel conditions. On the other hand, shorter packets may suffer from greater overhead. Hence, the optimal packet size must be chosen to enhance various performance metrics of WSNs. To this end, many approaches have been proposed to determine the optimum packet size in WSNs. In the literature, packet size optimization studies focus on a specific application or deployment environment. However, there is no comprehensive and recent survey paper that categorizes these different approaches. To address this need, in this paper, recent studies and techniques on data packet size optimization for terrestrial WSNs, underwater WSNs, wireless underground sensor networks, and body area sensor networks are reviewed to motivate the research community to further investigate this promising research area. The main objective of this paper is to provide a better understanding of different packet size optimization approaches used in different types of sensor networks and applications as well as introduce open research issues and challenges in this area.     

PKG‐VUL: Security Vulnerability Evaluation and Patch Framework for Package‐Based Systems

In information security and network management, attacks based on vulnerabilities have grown in importance. Malicious attackers break into hosts using a variety of techniques. The most common method is to exploit known vulnerabilities. Although patches have long been available for vulnerabilities, system administrators have generally been reluctant to patch their hosts immediately because they perceive the patches to be annoying and complex. To solve these problems, we propose a security vulnerability evaluation and patch framework called PKG‐VUL, which evaluates the software installed on hosts to decide whether the hosts are vulnerable and then applies patches to vulnerable hosts. All these operations are accomplished by the widely used simple network management protocol (SNMP). Therefore, system administrators can easily manage their vulnerable hosts through PKG‐VUL included in the SNMP‐based network management systems as a module. The evaluation results demonstrate the applicability of PKG‐VUL and its performance in terms of devised criteria.     

An amoeboid approach for identifying optimal citation flow in big scholarly data network

Scholarly big data network is a complex network of citations from research community across the globe. An effective scholar assessment structure is essential for scholars, researchers, and universities. The research publications are an important factor in the university rankings. The fast growth of digital publishing and scholarly data is progressively challenging every day. These days, the scholarly data can be accessed effortlessly through various data analysis techniques. In this paper, a new framework is designed for big scholarly data, and an amoeboid approach article‐optimal citation flow (A‐OCF) is used to find the optimal flow of citations in the big scholarly data network. A novel modern metrics for article quality (MMAQ) metric is proposed to identify the quality of articles. The performance analysis uses different bibliometric measures, including the impact factor citations, conference proceedings citations, and other citations with the purpose of measuring the quality of cited articles. The scholar analytic results are equated with existing techniques. We have also analyzed central articles in a research area through the MMAQ metrics and tested it with benchmark data sets.     

State-of-the-art survey of privacy-preserving data aggregation in wireless sensor networks

A state-of-the-art survey of privacy-preserving data aggregation techniques in wireless sensor networks was reviewed.Firstly,preliminaries were introduced,including network models,adversary models,and performance evaluation metrics.Secondly,existing related work was classified into several types according to privacy preservation techniques,such as homomorphic encryption,data perturbation,slicing-mixing technique,generalization,secure multiparty computation,and the key mechanisms of typical protocols were elaborated and analyzed.Finally,the promising future research directions were discussed.     

CogNS: A Simulation Framework for Cognitive Radio Networks

Cognitive radio technology has been used to efficiently utilize the spectrum in wireless networks. Although many research studies have been done recently in the area of cognitive radio networks (CRNs), little effort has been made to propose a simulation framework for CRNs. In this paper, a simulation framework based on NS2 (CogNS) for cognitive radio networks is proposed. This framework can be used to investigate and evaluate the impact of lower layers, i.e., MAC and physical layer, on the transport and network layers protocols. Due to the importance of packet drop probability, end-to-end delay and throughput as QoS requirements in real-time reliable applications, these metrics are evaluated over CRNs through CogNS framework. Our simulations demonstrate that the design of new network and transport layer protocols over CRNs should be considered based on CR-related parameters such as activity model of primary users, sensing time and frequency.     

Performance benchmarking of signaling in ATM networks

The overhead associated with establishing switched virtual circuits (SVCs) in high-speed wide area ATM networks is an important performance factor in applications with client/server architectures, including the World Wide Web and low-latency applications such as command/control and modeling/simulation. This article quantifies this overhead by describing a benchmarking framework implemented in a reliable, portable, and easily expandable toolset designed to conduct measurements of well-defined parameters and performance metrics on equipment that is either isolated or connected to a live network. The usefulness of this toolset is then demonstrated in a test suite applied to assess call rates and connection establishment latency of point-to-point and point-to-multipoint ATM connections in the MAGIC, ATDnet, and AAI WANs, on the campus ATM LAN at NRL, and on individual switches in our laboratories     

Investigation of multicast‐based mobility support in all‐IP cellular networks

To solve the IP mobility problem, the use of multicast has been proposed in a number of different approaches, applying multicast in different characteristic ways. We provide a systematic discussion of fundamental options for multicast‐based mobility support and the definition and experimental performance evaluation of selected schemes. The discussion is based on an analysis of the architectural, performance‐related, and functional requirements. By using these requirements and selecting options regarding network architecture and multicast protocols, we identify promising combinations and derive four case studies for multicast‐based mobility in IP‐based cellular networks. These case studies include both the standard any‐source IP multicast model as well as non‐standard multicast models, which optimally utilize the underlying multicast. We describe network architecture and protocols as well as a flexible software environment that allows to easily implement these and other classes of mobility‐supporting multicast protocols. Multicast schemes enable a high degree of flexibility for mobility mechanisms in order to meet the service quality required by the applications with minimal protocol overhead. We evaluate this overhead using our software environment by implementing prototypes and quantifying handoff‐specific metrics, namely, handoff and paging latency, packet loss and duplication rates, as well as TCP goodput. The measurement results show that these multicast‐based schemes improve handoff performance for high mobility in comparison to the reference cases: basic and hierarchical Mobile IP. Comparing the multicast‐schemes among each other the performance for the evaluated metrics is very similar. As a result of the conceptual framework classification and our performance evaluations, we justify specific protocol mechanisms that utilize specific features of the multicast. Based on this justification, we advocate the usage of a source‐specific multicast service model for multicast‐based mobility support that adverts the weaknesses of the classical Internet any‐source multicast service model. Copyright © 2006 John Wiley & Sons, Ltd.     

Similarity as a central approach to flow‐based anomaly detection

Network flow monitoring is currently a common practice in mid‐ and large‐size networks. Methods of flow‐based anomaly detection are subject to ongoing extensive research, because detection methods based on deep packets have reached their limits. However, there is a lack of comprehensive studies mapping the state of the art in this area. For this reason, we have conducted a thorough survey of flow‐based anomaly detection methods published on academic conferences and used by the industry. We have analyzed these methods using the perspective of similarity which is inherent to any anomaly detection method. Based on this analysis, we have proposed a new taxonomy of network anomalies and a similarity‐oriented classification of flow‐based detection methods. We have also identified four issues requiring further research: the lack of flow‐based evaluation datasets, infeasible benchmarking of proposed methods, excessive false positive rate and limited coverage of certain anomaly classes. Copyright © 2014 John Wiley & Sons, Ltd.     

Development of SNMP‐XML translator and gateway for XML‐based integrated network management

The research objective of our work is to develop a SNMP MIB to XML translation algorithm and to implement an SNMP‐XML gateway using this algorithm. The gateway is used to transfer management information between an XML‐based manager and SNMP‐based agents. SNMP is widely used for Internet management, but SNMP is insufficient to manage continuously expanding networks because of constraints in scalability and efficiency. XML–based network management architectures are newly proposed as alternatives to SNMP‐based network management, but the XML‐based Network Management System (XML‐based NMS) cannot directly manage legacy SNMP agents. We also implemented an automatic specification translator (SNMP MIB to XML Translator) and an SNMP‐XML gateway. Copyright © 2003 John Wiley &Sons, Ltd.     

A survey of cross‐layer protocols for IEEE 802.11 wireless multi‐hop mesh networks

There has been an escalation in deployment and research of wireless mesh networks by both the business community and academia in the last few years. Their attractive characteristics include low deployment cost, a low‐cost option to extend network coverage and ease of maintenance due to their self‐healing properties. Multiple routes exist between the sender and receiver nodes because of the mesh layout that ensures network connectivity even when node or link failures occur. Recent advances among others include routing metrics, optimum routing, security, scheduling, cross‐layer designs and physical layer techniques. However, there are still challenges in wireless mesh networks as discussed in this paper that need to be addressed. Cross‐layer design allows information from adjacent and non‐adjacent layers to be used at a particular layer for performance improvement. This paper presents a survey of cross‐layer protocol design approaches applied to the IEEE 802.11 standards for wireless multi‐hop mesh networks that have been proposed over the last few years for improved performance. We summarize the current research efforts in cross‐layer protocol design using the IEEE 802.11 standard in identifying unsolved issues that are a promising avenue to further research. Copyright © 2016 John Wiley & Sons, Ltd.     

On the need for dynamic downlink intercell interference coordination for realistic Long Term Evolution deployments

Intercell interference is the main issue limiting the capacity of modern orthogonal frequency‐division multiple access based cellular networks. Recently, extensive research work has been carried out in this field, and intercell interference coordination techniques have been recognized as key enablers of current (and future) cellular technologies. In this article, (i) a comprehensive survey of the most representative contributions is provided together with (ii) a generic methodology to measure their actual merit. The performance of several interference avoidance strategies has been evaluated both from system and user point of view in the context of a Long Term Evolution (LTE)‐based network considering not only synthetic cellular scenarios but also realistic deployments. Our literature review indicates that there is a need for adaptive/operator‐customizable low‐complex intercell interference coordination (ICIC) schemes suitable for realistic LTE deployments. Results obtained by means of a comprehensive set of simulations corroborate and support this premise. In this article, it is shown that simultaneous gains in terms of spectral/energy efficiency and fairness can be achieved through dynamic mechanisms with respect to both classic hard reuse schemes and static ICIC techniques. Besides numerical results, a novel merit assessment methodology based on several weighted performance metrics is proposed. Our findings show that dynamic schemes outperform static techniques by around 20–35% in realistic deployments. Copyright © 2012 John Wiley & Sons, Ltd.     

Contention‐free approaches for WiFi MAC design for VoIP services: performance analysis and comparison

The exponential growth in the demand of voice over internet protocol (VoIP) services along with the increasing demand for mobility in VoIP services has attracted great research efforts towards provisioning of VoIP services in IEEE 802.11‐based Wireless LANs (WiFi networks). We address one of the important research problems, namely, the quality of service (QoS)‐aware efficient silence suppression in the bursty voice traffic, for provisioning VoIP services in WiFi networks. The research works in the recent literature on silence suppression in voice calls have been surveyed categorising them on how the activity arrival is notified to the access point (AP). In most of the recent schemes, notification of uplink activity arrival is done through contention based medium access mechanisms such as the distributed coordination function (DCF). Contention‐based medium access causes non‐deterministic delays, therefore such schemes are not suited to voice traffic which require strict delay bound guarantees. This paper focuses on the schemes which do not use contention based approaches for silence suppression in voice traffic. Analytical performance evaluation and comparison of such schemes is carried out. Two very important performance metrics are modelled mathematically. One is the expected polling overhead time that the schedulers in these schemes can save per voice call during one voice activity cycle as compared to that in the round‐robin polling scheduler. The other is the expected unnecessary wireless channel access delay that a typical first talk‐spurt frame experiences due to the specific design of each scheme. The numerical results of this evaluation lead us to the conclusion whether or not and to what extent each of these schemes is viable. Copyright © 2008 John Wiley & Sons, Ltd.     

Bandwidth estimation: metrics, measurement techniques, and tools

In a packet network, the terms bandwidth and throughput often characterize the amount of data that the network can transfer per unit of time. Bandwidth estimation is of interest to users wishing to optimize end-to-end transport performance, overlay network routing, and peer-to-peer file distribution. Techniques for accurate bandwidth estimation are also important for traffic engineering and capacity planning support. Existing bandwidth estimation tools measure one or more of three related metrics: capacity, available bandwidth, and bulk transfer capacity. Currently available bandwidth estimation tools employ a variety of strategies to measure these metrics. In this survey we review the recent bandwidth estimation literature focusing on underlying techniques and methodologies as well as open source bandwidth measurement tools.     

On the differentiated QoE enforcement between competing scalable video flows over wireless networks

In differentiated quality‐of‐experience enforcement (QoE) for video transmission over wireless networks, accurate video quality metrics play a crucial role in the designing process of optimal resource assignment algorithms. Many cross‐layer optimization‐based rate‐allocation strategies, which consider different objective functions (congestion level, total packet loss, etc.), have been developed for this purpose. The main contributions of the proposed work are twofold. Firstly, an optimal resource assignment framework is being developed in which, based on some network‐specific constraints and by incorporating appropriate video quality metrics, the total weighted QoE of some competing scalable video sources is being optimized based on cross‐layer optimization techniques. Secondly, these optimal rates can be used for differentiated QoE enforcement between multiple competing scalable video sources. The resulting optimal rates can be considered as rate feedbacks for online rate adaptation of a moderate scalable video encoder such as H.264/MPEG‐4 advanced video coding. The aforementioned weight parameters are selected based on the importance of each video sequence's quality and can be associated with some previous service level agreement‐based prices. Some numerical analysis have been presented to validate the theoretical results and to verify the claims. Copyright © 2011 John Wiley & Sons, Ltd.     

Exploiting secure performance in power domain–based multiple access: Impacts of relay link/direct link and secure analysis

A new design of secure nonorthogonal multiple access (NOMA) deployed together with cooperative relaying network is investigated in two modes including direct link and relay link. This paper proposes a mathematical analysis under secrecy considerations of a downlink two‐user NOMA systems. In particular, physical layer security of NOMA is studied in two specific metrics to achieve secure performance analysis such as the secrecy outage probability (SOP) and probability of strictly positive secrecy capacity (SPSC). It should be further explored the situation as the illegal user which is assumed to be eavesdropper at the information level, it attempts to decode the information intended to legal users while NOMA scheme is employed for legal users. The transmission techniques of NOMA equipping relaying architecture (dual‐hop transmission) have proposed due to improving the spectrum efficiency greatly compared with the traditional single‐hop networks. Finally, this study shows the advantages of NOMA over the traditional orthogonal multiple access in the studied problems analytically and numerical analysis is further provided. As important achievement, new exact and closed‐form expressions of the SOP and SPSC are derived, and they will be confirmed by simulation, ie, Monte Carlo simulations are performed to verify the proposed analytical results. Ultimately, the effects of some critical factors are studied on secure performance through these simulation results.     

A novel dimensionality reduction technique based on kernel optimization through graph embedding

In this paper, we propose a new method for kernel optimization in kernel-based dimensionality reduction techniques such as kernel principal component analysis and kernel discriminant analysis. The main idea is to use the graph embedding framework for these techniques and, therefore, by formulating a new minimization problem to simultaneously optimize the kernel parameters and the projection vectors of the chosen dimensionality reduction method. Experimental results are conducted in various datasets, varying from real-world publicly available databases for classification benchmarking to facial expressions and face recognition databases. Our proposed method outperforms other competing ones in classification performance. Moreover, our method provides a systematic way to deal with kernel parameters whose calculation was treated rather superficially so far and/or experimentally, in most of the cases.