Cistech Ltd

Ottawa, Canada

Cistech Ltd

Ottawa, Canada
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Melhem S.B.,Concordia University at Montréal | Agarwal A.,Concordia University at Montréal | Goel N.,Concordia University at Montréal | Zaman M.,Cistech Ltd
2017 8th International Conference on Information and Communication Systems, ICICS 2017 | Year: 2017

Live virtual machine (VM) migration is defined as a technique that migrates the entire operating system (OS) and its associated applications from one host/physical server to another providing that users should not notice any interruption in their services. Live VM migration plays an important role to facilitate online maintenance, load balancing, and energy management as part of resource management. Live VM migration can be divided into two parts: 1) selection process which involves three different phases: when to trigger the migration, which VMs must be selected to be migrated, and which destination host must be chosen to move the selected VMs. 2) migration process that targets moving the VM in minimum time to avoid any interruption of services. In this paper, we present a comparative study of selection approaches used in the live VM migration technique. © 2017 IEEE.


Lim N.,Carleton University | Majumdar S.,Carleton University | Srivastava V.,Cistech Ltd
International Journal of Parallel, Emergent and Distributed Systems | Year: 2015

Providing secure communication in distributed systems often introduces a performance penalty due to the CPU-intensive operations used by security protocols such as the Secure Sockets Layer (SSL) protocol. This paper proposes a technique, called security sieve, which enhances the performance of SSL-based document transmission. Security sieve separates the sensitive components from the non-sensitive components, and transmits the separated components over a secure channel and a (faster) non-secure channel, respectively. At the receiving end, the separated components are re-assembled to reconstruct the original document. A significant performance improvement with security sieve is observed for a number of system and workload parameters. © 2015 Taylor & Francis


Lim N.,Carleton University | Majumdar S.,Carleton University | Srivastava V.,Cistech Ltd
2012 IEEE 31st International Performance Computing and Communications Conference, IPCCC 2012 | Year: 2012

Sending documents containing sensitive information is commonly performed on distributed systems. To protect the sensitive data in the documents, these documents need to be transmitted over a secure channel. However, secure communications can often increase the data transmission time due to the CPU-intensive operations (e.g. encryption/decryption) that need to be applied to the data before the data transfer. This paper focuses on a performance optimization technique called security sieve, which aims to enhance the performance of SSL/TLS-based data transmission. Security sieve reduces the transmission time of transferring classified documents, which may also contain non-sensitive data, by minimizing the time spent performing the CPU-intensive security-related operations. This paper focuses on highlighting the performance optimization principles/performance patterns that were used and includes a discussion of a prototype implementation. In addition, experimental results are presented to demonstrate the performance enhancement provided by security sieve. © 2012 IEEE.


Zhu J.,Carleton University | Lung C.-H.,Carleton University | Srivastava V.,Cistech Ltd
2013 9th International Wireless Communications and Mobile Computing Conference, IWCMC 2013 | Year: 2013

Clustering is one of the most energy-efficient methods to organize sensor nodes in Wireless Sensor Networks (WSNs). To perform clustering, location data are usually used for calculating the distance between sensor nodes. But location data may not always be available due to Global Positioning System (GPS) failures or may not be practical in consideration of cost. Alternatively, Received Signal Strength (RSS) or RSS Indicator (RSSI) is used as the distance estimator, but it has been showed that RSS or RSSI is unreliable in many studies. In order to mitigate these problems, we propose a hybrid clustering protocol - Hybrid Distributed Hierarchical Agglomerative Clustering (H-DHAC) - which uses both quantitative location data and binary qualitative connectivity data in clustering for WSNs. Our simulation results show that H-DHAC has a lower percentage of compromise in performance in terms of network life time and total transmitted data compared to similar approaches that use complete location data. However, H-DHAC still outperforms the well known clustering protocols, e.g., LEACH and LEACH-C. © 2013 IEEE.


Zhu J.,Carleton University | Lung C.-H.,Carleton University | Srivastava V.,Cistech Ltd
Ad Hoc Networks | Year: 2015

Clustering is an efficient method to organize sensor nodes in Wireless Sensor Networks (WSNs) for data transmissions and energy saving. To perform clustering, many methods require geographic location data for calculating the distance between sensor nodes. But location data may not always be available due to Global Positioning System (GPS) failures or may not be practical in consideration of all sensor nodes due to the high cost and energy consumption of GPS. Alternatively, Received Signal Strength (RSS) or RSS Indicator (RSSI) has been used to estimate the distance. But many studies have shown that RSS or RSSI is not reliable in practice. In order to mitigate these realistic problems, this paper proposes a hybrid clustering protocol - Hybrid Distributed Hierarchical Agglomerative Clustering (H-DHAC) - which uses both quantitative location data and binary qualitative connectivity data in clustering for WSNs. Our simulation results reveal that H-DHAC only has a slightly lower percentage of compromise in performance in terms of network life time and total transmitted data compared to similar approaches that use complete location data. However, H-DHAC still outperforms the well known clustering protocols, e.g., LEACH and LEACH-C. On the other hand, the cost of H-DHAC can be significantly lower in comparison to those approaches that use complete quantitative location data, as GPS is not required for all sensor nodes. In addition, H-DHAC still can be operational in the presence of GPS failures. © 2014 Elsevier B.V.


Abdelkader T.,Ain Shams University | Naik K.,University of Waterloo | Nayak A.,University of Ottawa | Goel N.,Cistech Ltd | Srivastava V.,Cistech Ltd
IEEE Network | Year: 2016

Networks that lack continuous end-to-end connections among their nodes due to node mobility, constrained power sources, or limited data storage space are called DTNs. To overcome the intermittent connectivity, DTN nodes store and carry the data packets they receive until they come into communication range of each other. In addition, they spread multiple copies of the same packet on the network to increase the delivery probability. In recent years, several routing protocols have been developed specifically for DTNs. These protocols vary in the number of copies they spread and the information they use to guide the packets to their destinations. There have been some reviews of those protocols, but no performance comparison has been conducted. In this article, we study four well-known DTN routing protocols: EPIDEMIC, Spray-and-Wait, PROPHET, and MAXPROP. We introduce a procedural form to present the protocols. We measure the performance of the protocols in terms of packet delivery, delivery cost, and average packet delay. We compare the protocols' performance together with the results of optimal routing using real-life scenarios of vehicles and pedestrians roaming in a city. We conduct several simulation experiments to show the impact of changing buffer capacity, packet lifetime, packet generation rate, and number of nodes on the performance metrics. The article is concluded by providing guidelines to develop an efficient DTN routing protocol. To the best of our knowledge, this work is the first to provide a detailed performance comparison among the diverse collection of DTN routing protocols. © 1986-2012 IEEE.


Abdelkader T.,Ain Shams University | Naik K.,University of Waterloo | Nayak A.,University of Ottawa | Goel N.,Cistech Ltd | Srivastava V.,Cistech Ltd
IEEE Transactions on Parallel and Distributed Systems | Year: 2013

Delay tolerant networks (DTN) are characterized by a lack of continuous end-to-end connections due to node mobility, constrained power sources, and limited data storage space of some or all of its nodes. To overcome the frequent disconnections, DTN nodes are required to store data packets for long periods of time until they come near other nodes. Moreover, to increase the delivery probability, they spread multiple copies of the same packet on the network so that one of them reaches the destination. Given the limited storage and energy resources of many DTN nodes, there is a tradeoff between maximizing delivery and minimizing storage and energy consumption. In this paper, we study the routing problem in DTN with limited resources. We formulate a mathematical model for optimal routing, assuming the presence of a global observer that can collect information about all the nodes in the network. Next, we propose a new protocol based on social grouping among the nodes to maximize data delivery while minimizing network overhead by efficiently spreading the packet copies in the network. We compare the new protocol with the optimal results and the existing well-known routing protocols using real life simulations. Results show that the proposed protocol achieves higher delivery ratio and less average delay compared to other protocols with significant reduction in network overhead. © 1990-2012 IEEE.


Khalifa T.,University of Waterloo | Abdrabou A.,United Arab Emirates University | Naik K.,University of Waterloo | Alsabaan M.,King Saud University | And 2 more authors.
IEEE Transactions on Smart Grid | Year: 2014

This paper introduces our proposed Split-and Aggregated-TCP (SA-TCP) scheme's enhanced TCP performance in a smart metering infrastructure (SMI). The scheme is based on upgrading intermediate devices (e.g., regional collectors) to aggregate TCP connections. An SA-TCP aggregator collects data packets from smart meters in a certain region over separate TCP connections, then reliably aggregates them in one TCP connection to the management server of the utility. Our proposed scheme responds better to data traffic dynamics of smart meters and makes TCP congestion control effective. © 2013 IEEE.


Khalifa T.,University of Waterloo | Abdrabou A.,United Arab Emirates University | Naik K.,University of Waterloo | Alsabaan M.,University of Waterloo | And 2 more authors.
2012 IEEE 3rd International Conference on Smart Grid Communications, SmartGridComm 2012 | Year: 2012

This paper investigates the TCP's congestion control mechanism effectiveness for smart meters. We show that the classic congestion control causes a high loss rate for metered data and disrupts competing traffic flows in a shared network. © 2012 IEEE.


Melhem S.B.,Concordia University at Montréal | Daradkeh T.,Concordia University at Montréal | Agarwal A.,Concordia University at Montréal | Goel N.,Cistech Ltd
International Conference on Computing, Communication and Automation, ICCCA 2015 | Year: 2015

Cloud computing is a new computing paradigm, which utilizes dissipated resource benefits and supports resource sharing and time access flexibility. In addition, cloud provides different kinds of services mapped to users needs such as Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a service (IaaS). There are two different types of cloud implementations: commercial cloud solutions such as Amazon Elastic Compute Cloud (Amazon EC2) and Microsoft Azure; and non-commercial (open source) cloud solutions such as Apache VCL and Open-Stack cloud. This paper discusses the Apache VCL cloud framework, its architecture, functionality, properties, and its workflow. It helps the user target groups, such as students, teachers and researchers to verify the VCL. © 2015 IEEE.

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