Ljiljana Trajkovic

Simon Fraser University · School of Engineering Science

Cyber attacks are becoming more sophisticated and, hence, more difficult to detect. Using efficient and effective machine learning techniques to detect network anomalies and intrusions is an important aspect of cyber security. A variety of machine learning models have been employed to help detect malicious intentions of network users. In this paper...

While there has been considerable work addressing consensus and group consensus in single-layer networks, not much attention has been devoted to consensus in multilayer networks. In this paper, we fill this gap by considering multilayer networks consisting of agents of different types while agents of the same type are arranged in individual layers....

This book constitutes the refereed proceedings of the First Symposium on Machine Learning and Metaheuristics Algorithms, and Applications, held in Trivandrum, India, in December 2019. The 17 full papers and 6 short papers presented in this volume were thoroughly reviewed and selected from 53 qualified submissions. The papers cover such topics as m...

This book explores and discusses various aspects of intelligent systems technologies and their applications. Presenting the refereed post-conference proceedings of the 5th International Symposium on Intelligent Systems Technologies and Applications (ISTA 2019), held at the Indian Institute of Information Technology and Management-Kerala (IIITM-K),...

Detecting anomalies and intrusions in communication networks is of great interest in cyber security. In this paper, we use Support Vector Machine (SVM) and Broad Learning System (BLS) supervised machine learning approaches to detect anomalies and intrusions in datasets collected from packet data networks. The developed models are trained and tested...

In this chapter, we apply various machine learning techniques for classification of known network anomalies. The models are trained and tested on various collected datasets. With the advent of fast computing platforms, many neural network-based algorithms have proved useful in detecting BGP anomalies. Performance of classification algorithms depend...

In this paper, we consider resource allocation in data networks and evaluate the performance of various approaches using the Cross-Stratum Optimization architecture for a provider-centric use case. We describe many approaches used to provision various requests related to a data center operations. We consider three simple approaches and compare them...

Detecting, analyzing, and defending against cyber threats is an important topic in cyber security. Applying machine learning techniques to detect such threats has received considerable attention in research literature. Anomalies of Border Gateway Protocol (BGP) affect network operations and their detection is of interest to researchers and practiti...

Professors Radoslav Horvat and Mirko Milić taught theory of electrical circuits in the Faculty of Electrical Engineering at the University of Belgrade during the second half of the 20th century. They introduced the most up-to-date topics in their courses and for decades educated thousands of engineers and scientists. They established a well-known “...

Network virtualization helps overcome shortcomings of the current Internet architecture. The virtualized network architecture enables coexistence of multiple virtual networks (VNs) on an existing physical infrastructure. VN embedding (VNE) problem, which deals with the embedding of VN components onto a physical network, is known to be NP-hard. In t...

Recounts the career and contributions of William Almer Gruver.

Presents the President's message for this issue of the publication.

Understanding modern data communication networks such as the Internet involves collection and analysis of data collected from deployed networks. It also calls for development of various tools for analysis of such datasets. Collected traffic data are used for characterization and modeling of network traffic, analysis of Internet topologies, and pred...

Women represent approximately 51% of the total population. Over the course of history, the demographics of the workforce have changed significantly. Women continue to advance, holding important roles and positions in both academia and industry. Although progress has been made, the precipitous journey is not yet complete. Global concerns about curre...

Presents the President's message for this issue of the publication.

The exponential growth of the Routing Information Base (RIB) of the Internet's Default-Free Zone (DFZ) routers has raised concerns about non-scalability of the current Internet's routing architecture. The main reason is that Internet addresses currently carry information about both the identity and location (physical connection point) of devices co...

Very High Throughput Multi-User Multiple Input Multiple Output (VHT MU-MIMO) is an 802.11ac communication mode that allows an Access Point (AP) to simultaneously transmit multiple data streams as Aggregated Multi-Protocol Data Units (A-MPDUs) to a group of multiple stations (STAs) over the same channel. This mode combines communication technologies...

Presents the President???s Message for this issue of the publication.

Changes in the network topology such as large-scale power outages or Internet worm attacks are events that may induce routing information updates. Border Gateway Protocol (BGP) is by Autonomous Systems (ASes) to address these changes. Network reachability information, contained in BGP update messages, is stored in the Routing Information Base (RIB)...

Presents the President???s Message for this issue of the publication.

Deflection routing is employed to ameliorate packet loss caused by contention in buffer-less architectures such as optical burst-switched networks. The main goal of deflection routing is to successfully deflect a packet based only on a limited knowledge that network nodes possess about their environment. In this paper, we present a framework that i...

Border Gateway Protocol (BGP) is the core component of the Internet's routing infrastructure. Abnormal routing behavior impairs global Internet connectivity and stability. Hence, designing and implementing anomaly detection algorithms is important for improving performance of routing protocols. While various machine learning techniques may be emplo...

Contention is the main source of information loss in buffer-less network architectures where deflection routing is a viable contention resolution scheme. In recent years, various reinforcement learning-based deflection routing algorithms have been proposed. However, performance of these algorithms has not been evaluated in larger networks that rese...

In this paper, we introduce a predictive Q-learning deflection routing (PQDR) algorithm for buffer-less networks. Q-learning, one of the reinforcement learning (RL) algorithms, has been considered for routing in computer networks. The RL-based algorithms have not been widely deployed in computer networks where their inherent random nature is undesi...

In this paper, we derive the exact expression for the packet error probability in the case of m-path diversity scheme with packet combining using majority decision technique. The individual paths are modeled as independent and slow-varying binary symmetric channels with distinct values for bit error probabilities. We introduce an equivalent channel...

In this paper, we propose a Q-learning based deflection routing algorithm that may be employed to resolve contention in optical burst-switched networks. The main goal of deflection routing is to successfully deflect a burst based only on a limited knowledge that network nodes possess about their environment. Q-learning, one of the reinforcement lea...

Collecting network traffic traces from deployed networks is one of the basic steps in understanding communication networks. Traffic traces are used for network management, traffic engineering, packet classification, and analyzing user behavior to ensure adequate quality of service. Monitored traffic traces should be anonymized for privacy and secur...

Over the last decade, complex networks have emerged to be a promising research field in the area of circuits and systems. This mini-review paper introduces the special session that deals with theory and applications of complex networks and provides brief review of their advances and challenges. The paper further promotes some important research top...

The Minimal Route Advertisement Interval (MRAI) plays a prominent role in convergence of the Border Gateway Protocol (BGP). Previous studies have suggested using adaptive MRAI and reusable timers to reduce the BGP convergence time. The adaptive MRAI timers perform well under the normal load of BGP updates. However, a large number of BGP updates may...

In this paper, we derived an analytical expression for the throughput efficiency in a GBN ARQ telecommunication scheme with the xor packet combining. The analysis was based on retransmission cycles. Results show that including the xor packet combining leads to better performance compared to the ordinary single copy GBN ARQ scheme.

Finding a circuit's dc operating points is an essential step in its design and involves solving systems of nonlinear algebraic equations. Of particular research and practical interests are dc analysis and simulation of electronic circuits consisting of bipolar junction and field-effect transistors (BJTs and FETs), which are building blocks of moder...

Traffic anomalies in communication networks greatly degrade network performance. Early detection of such anomalies alleviates their effect on network performance. A number of approaches that involve traffic modeling, signal processing, and machine learning techniques have been employed to detect network traffic anomalies. In this paper, we develop...

Worms such as Slammer, Nimda, and Code Red I are anomalies that affect performance of the global Internet Border Gateway Protocol (BGP). BGP anomalies also include Internet Protocol (IP) prefix hijacks, miss-configurations, and electrical failures. Statistical and machine learning techniques have been recently deployed to classify and detect BGP an...

The IEEE 802.16 Worldwide Interoperability for Microwave Access (WiMAX) standard is widely used for fixed and mobile Internet access. WiMAX provides maximum data rate of 75 Mbps and high-speed Internet access to a wide range of devices used by clients over the last mile. Asymmetric Digital Subscriber Line (ADSL) is widely used to provide guaranteed...

Wireless Fidelity (WiFi) network is based on the IEEE 802.11 standard. Worldwide Interoperability for Microwave Access (WiMAX), based on IEEE 802.16, is a standard with similar principles. The main advantage of WiMAX over WiFi is that it covers larger areas and has higher data rates. WiMAX network operators provide WiMAX subscriber units that enabl...

Routing protocols are key elements of modern communication networks. Currently deployed dynamic routing protocols that are used to propagate network topology information to the neighboring routers are Routing Information Protocol (RIP), Enhanced Interior Gateway Routing Protocol (EIGRP), and the Open Shortest Path First (OSPF) protocol. The choice...

Wireless ad-hoc networks are decentralized wireless networks that do not rely on an infrastructure, such as base stations or access points. Routing protocols in ad-hoc networks specify communication between routers and enable them to select routes between a source and a destination. The choice of the routes is performed by routing algorithms. In th...

In this paper, we address routing in complex networks. Routing traffic across a network requires finding best possible paths between sources and destinations. When data traffic changes dynamically, a path that was optimal in the past may not be the best for the next packet. Adapting to traffic changes and finding optimal paths dynamically are chall...

In this paper, we present the prediction-based particle filter approach for processing motion and force data in teleoperation over the Internet. We first introduce the prediction-based particle filter algorithm, one of the Sequential Monte Carlo methods based on the recursive Bayesian prediction. The prediction algorithm is applied to dynamic model...

The Border Gateway Protocol (BGP) is the de facto Internet routing protocol. Various aspects of the BGP protocol have been analyzed using mathematical and experimental approaches. Formal verification of BGP specification validates whether or not a specific set of requirements is satisfied. In resent years, the probabilistic behavior of BGP has been...

Border Gateway Protocol (BGP) is an InterAutonomous System routing protocol that operates over the reliable Transmission Control Protocol (TCP). The most important function ofa BGP speaker is to exchange network reachability information with other speakers. In this paper, we describe collection and preliminary analysis ofBCNET traffic. The traffic...

Understanding circuits is fundamental to electric engineering and continuing to offer courses in theory and applications of electric circuits to new generations of engineering students remains an important part of any engineering curriculum. Attracting new generations of students to circuits is a challenging task that calls for new approaches, meth...

Parallel structures may be used to increase a system processing speed in case of large amount of data or highly complex calculations. Dynamic Voltage and Frequency Scaling (DVFS) may be used for simpler calculations in order to decrease the system voltage or frequency and achieve lower power consumption. Combining these two mechanisms may lead to h...

WiMAX (Worldwide Interoperability for Microwave Access) embodies the IEEE 802.16 family of standards that provision wireless broadband access. With the IEEE 802.16e−2005 mobility amendment, WiMAX promises to address the ever-increasing demand for mobile high speed wireless data in fourth-generation (4G) networks. WiMAX market studies continue to pr...

In this paper, we derive a closed-form expression for the packet error probability in a three-branch diversity transmission scheme with distinct bit error probabilities in each branch and a majority combining technique implemented on a data link layer. Based on the derived expression and its approximate form, we also demonstrate that the proposed t...

This poster paper describes testbed for collection of BCNET Border Gateway Protocol (BGP) traffic. The BGP traffic was collected using special purpose hardware and software. Preliminary data collection was illustrated using the Wireshark and Walrus graph visualization tools.

Abstract: In this talk, we survey spectral graph theory as a tool for analyzing topology of complex networks. We show its importance in understanding dynamical behavior of complex networks and illustrate its application to analyzing the development and evolution of the Internet.

IEEE 802.16e is a Worldwide Interoperability Microwave Access (WiMAX) standard that supports mobility. Handover is one of the most important factors that affect the performance of a WiMAX network. Various handover schemes have been proposed and implemented. In this paper, we propose Dual-Trigger Handover (DTHO) algorithm for WiMAX networks. The pro...

An Internet-based teleoperation system is an interactive application where a human user transmits movement data of a robotic device while simultaneously receiving reflected force data from a remote teleoperator. Performance of such real-time applications is highly sensitive to the Internet delay and data loss. In this paper, we describe the efficie...

The discovery of power-laws and spectral properties of the Internet topology illustrates a complex underlying network infrastructure that carries a variety of the Internet applications. Analysis of spectral properties of the Internet topology is based on matrices of graphs capturing Internet structure on the Autonomous System (AS) level. The analys...

The discovery of power-laws and spectral properties of the Internet topology indicates a complex underlying network infrastructure. Analysis of spectral properties of the Internet topology has been usually based on the normalized Laplacian matrix of graphs capturing Internet structure on the Autonomous System (AS) level. In this paper, we first ext...

In this paper, we present motion and force predictions in Internet-based teleoperation systems using the particle filter method. The particle filter, also known as the sequential Monte Carlo (SMC) method, is a probabilistic prediction or estimation technique within a sequential Bayesian framework: Data at a current time step are predicted or estima...

It has been observed that Internet gateways employing Transport Control Protocol (TCP) and the Random Early Detection (RED) control algorithm may exhibit instability and oscillatory behavior. Most control methods proposed in the past have been based on analytical models that rely on statistical measurements of network parameters. In this paper, we...

Discovering properties of the Internet topology is important for evaluating performance of various network protocols and applications. The discovery of power-laws and the application of spectral analysis to the Internet topology data indicate a complex behavior of the underlying network infrastructure that carries a variety of the Internet applicat...

The experiences and views leading to further interactions and role models with the introduction and outline of the circuit and systems (CAS) education are presented. The basic circuits and systems courses are designed based on the courses in mathematics and physics, and digital signal processing and control theory. Engineers presently face increasi...

The Circuits and Systems Education Workshop held in conjunction with ISAS 2008 in Seattle in May 2008, offered a collection of regional experiences and personal views regarding circuits and systems education (CAS). The topics addressed at the workshop include basic circuits versus digital signal processing (DSP), need to design tailored circuits, a...

Worldwide Interoperability for Microwave Access (WiMAX) embodies the IEEE 802.16 family of standards that provide wireless broadband access to residential and commercial Internet subscribers. While other WiMAX applications exist, there is an increasing trend to employ WiMAX for last-mile Internet access to circumvent the high deployments costs and...

It has been observed that the TCP-RED system may exhibit instability and oscillatory behavior. Control methods proposed in the past have been based on the analytical models that rely on statistical measurements of network parameters. In this paper, we apply the detrended fluctuation analysis (DFA) method to analyze stability of the TCP-RED system....

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Worldwide Interoperability for Microwave Access (WiMAX) embodies the IEEE 802.16 family of standards that provide wireless broadband access to residential and commercial Internet subscribers. While other WiMAX applications exist, there is an increasing trend to employ WiMAX for last-mile Internet access to circumvent the high deployments costs and...

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Satellite data networks provide broadband access for areas not served by traditional broadband technologies. In this paper, we describe a collection of traffic data (billing records and tcpdump traces) from a satellite Internet service provider in China. We use the billing records to investigate the uploaded and downloaded traffic volume and the ag...