Browsing by Author "Kim, Dongsoo S."

Now showing 1 - 9 of 9
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    Average Consensus in Wireless Sensor Networks with Probabilistic Network Links
    (2010) Saed, Steve; Li, Lingxi; Kim, Dongsoo S.; King, Brian
    This study proposes and evaluates an average consensus scheme for wireless sensor networks. For this purpose, two communication error models, the fading signal error model and approximated fading signal error model, are introduced and incorporated into the proposed decentralized average consensus scheme. Also, a mathematical analysis is introduced to derive the approximated fading signal model from the fading signal model. Finally, differnt simulation scenarios are introduced and their results analyzed to evaluate the performance of the proposed scheme and its effectiveness in meeting the needs of wireless sensor networks.
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    Critical-Path Aware Scheduling for Latency Efficient Broadcast in Duty-Cycled Wireless Sensor Networks
    (Hindawi, 2018) Le, Duc-Tai; Im, Giyeol; Le Duc, Thang; Zalyubovskiy, Vyacheslav V.; Kim, Dongsoo S.; Choo, Hyunseung; Electrical and Computer Engineering, School of Engineering and Technology
    Minimum latency scheduling has arisen as one of the most crucial problems for broadcasting in duty-cycled Wireless Sensor Networks (WSNs). Typical solutions for the broadcast scheduling iteratively search for nodes able to transmit a message simultaneously. Other nodes are prevented from transmissions to ensure that there is no collision in a network. Such collision-preventions result in extra delays for a broadcast and may increase overall latency if the delays occur along critical paths of the network. To facilitate the broadcast latency minimization, we propose a novel approach, critical-path aware scheduling (CAS), which schedules transmissions with a preference of nodes in critical paths of a duty-cycled WSN. This paper presents two schemes employing CAS which produce collision-free and collision-tolerant broadcast schedules, respectively. The collision-free CAS scheme guarantees an approximation ratio of in terms of latency, where denotes the maximum node degree in a network. By allowing collision at noncritical nodes, the collision-tolerant CAS scheme reduces up to 10.2 percent broadcast latency compared with the collision-free ones while requiring additional transmissions for the noncritical nodes experiencing collisions. Simulation results show that broadcast latencies of the two proposed schemes are significantly shorter than those of the existing methods.
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    Critical-Path Aware Scheduling for Latency Efficient Broadcast in Duty-Cycled Wireless Sensor Networks
    (Hindawi, 2018) Le, Duc-Tai; Im, Giyeol; Le Duc, Thang; Zalyubovskiy, Vyacheslav V.; Kim, Dongsoo S.; Choo, Hyunseung; Electrical and Computer Engineering, School of Engineering and Technology
    Minimum latency scheduling has arisen as one of the most crucial problems for broadcasting in duty-cycled Wireless Sensor Networks (WSNs). Typical solutions for the broadcast scheduling iteratively search for nodes able to transmit a message simultaneously. Other nodes are prevented from transmissions to ensure that there is no collision in a network. Such collision-preventions result in extra delays for a broadcast and may increase overall latency if the delays occur along critical paths of the network. To facilitate the broadcast latency minimization, we propose a novel approach, critical-path aware scheduling (CAS), which schedules transmissions with a preference of nodes in critical paths of a duty-cycled WSN. This paper presents two schemes employing CAS which produce collision-free and collision-tolerant broadcast schedules, respectively. The collision-free CAS scheme guarantees an approximation ratio of in terms of latency, where denotes the maximum node degree in a network. By allowing collision at noncritical nodes, the collision-tolerant CAS scheme reduces up to 10.2 percent broadcast latency compared with the collision-free ones while requiring additional transmissions for the noncritical nodes experiencing collisions. Simulation results show that broadcast latencies of the two proposed schemes are significantly shorter than those of the existing methods.
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    Energy Efficient Multipath Ant Colony Based Routing Algorithm for Mobile Ad hoc Networks
    (Elsevier, 2021-03) Sharma, Arush; Kim, Dongsoo S.; Electrical and Computer Engineering, School of Engineering and Technology
    This paper describes the novel wireless routing protocol made for mobile ad hoc networks or wireless sensor networks using the bio-inspired technique. Bio-inspired algorithms include the routing capabilities taken from the social behavior of ant colonies, bird flocking, honey bee dancing, etc and promises to be capable of catering to the challenges posed by wireless sensors. Some of the challenges of wireless sensor networks are limited bandwidth, limited battery life, low memory, etc. An energy-efficient multipath routing algorithm based on the foraging nature of ants is proposed including many meta-heuristic impact factors to provide good robust paths from source to destination to overcome the challenges faced by resource-constrained sensors. Analysis of individual impact factor is represented which justifies their importance in routing performance. The multi-path routing feature is claimed by showing energy analysis as well as statistical analysis in-depth to the readers. The proposed routing algorithm is analyzed by considering various performance metrics such as throughput, delay, packet loss, network lifetime, etc. Finally, the comparison is done against AODV routing protocol by considering performance metrics where the proposed routing algorithm shows a 49% improvement in network lifetime.
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    Increasing CNN representational power using absolute cosine value regularization
    (2020-05) Singleton, William S.; El-Sharkawy, Mohamed A.; King, Brian S.; Kim, Dongsoo S.
    The Convolutional Neural Network (CNN) is a mathematical model designed to distill input information into a more useful representation. This distillation process removes information over time through a series of dimensionality reductions, which ultimately, grant the model the ability to resist noise, and generalize effectively. However, CNNs often contain elements that are ineffective at contributing towards useful representations. This Thesis aims at providing a remedy for this problem by introducing Absolute Cosine Value Regularization (ACVR). This is a regularization technique hypothesized to increase the representational power of CNNs by using a Gradient Descent Orthogonalization algorithm to force the vectors that constitute their filters at any given convolutional layer to occupy unique positions in in their respective spaces. This method should in theory, lead to a more effective balance between information loss and representational power, ultimately, increasing network performance. The following Thesis proposes and examines the mathematics and intuition behind ACVR, and goes on to propose Dynamic-ACVR (D-ACVR). This Thesis also proposes and examines the effects of ACVR on the filters of a low-dimensional CNN, as well as the effects of ACVR and D-ACVR on traditional Convolutional filters in VGG-19. Finally, this Thesis proposes and examines regularization of the Pointwise filters in MobileNetv1.
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    Leveraging proxy mobile IPv6 with SDN
    (IEEE, 2016-09) Raza, Syed M.; Kim, Dongsoo S.; Shin, DongRyeol; Choo, Hyunseung; Department of Electrical and Computer Engineering, School of Engineering and Technology
    The existing Proxy Mobile IPv6 suffers from a long handover latency which in turn causes significant packet loss that is unacceptable for seamless realtime services such as multimedia streaming. This paper proposes an OpenFlow-enabled proxy mobile IPv6 (OF-PMIPv6) in which the control of access gateways is centralized at an OpenFlow controller of a foreign network. The proposed OF-PMIPv6 separates the control path from the data path by performing the mobility control at the controller, whereas the data path remains direct between a mobile access gateway and a local mobility anchor in an IP tunnel form. A group of simple OpenFlow-enabled access gateways performs link-layer control and monitoring activities to support a comprehensive mobility of mobile nodes, and communicates with the controller through the standard OpenFlow protocol. The controller performs networklayer mobility control on behalf of mobile access gateways and communicates with the local mobility anchor in the Proxy Mobile IPv6 domain. Benefiting from the centralized view and information, the controller caches the authentication and configuration information and reuses it to significantly reduce the handover latency. An analytical analysis of the proposed OF-PMIPv6 reactive and proactive handover schemes shows 43% and 121% reduction in the handover latency, respectively, for highly utilized network. The results gathered from the OF-PMIPv6 testbed suggest similar performance improvements.
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    Robust Ant Colony Based Routing Algorithm For Mobile Ad-Hoc Networks
    (2019-08) Sharma, Arush S.; Kim, Dongsoo S.; King, Brian; El-Sharkawy, Mohamed
    This thesis discusses about developing a routing protocol of mobile ad hoc networks in a bio inspired manner. Algorithms inspired by collective behaviour of social insect colonies, bird flocking, honey bee dancing, etc., promises to be capable of catering to the challenges faced by tiny wireless sensor networks. Challenges include but are not limited to low bandwidth, low memory, limited battery life, etc. This thesis proposes an energy efficient multi-path routing algorithm based on foraging nature of ant colonies and considers many other meta-heuristic factors to provide good robust paths from source node to destination node in a hope to overcome the challenges posed by resource constrained sensors.
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    Robust Bio-Inspired Routing Protocol in MANETs Using Ant Approach
    (Springer, 2019) Sharma, Arush; Kim, Dongsoo S.; Electrical and Computer Engineering, School of Engineering and Technology
    This paper discusses about developing a routing protocol for mobile ad-hoc networks in a bio-inspired manner. Algorithms inspired by collective behavior of social insect colonies, bird flocking, honey bee dancing, etc., promise to be capable of catering to the challenges faced by tiny wireless sensor networks. We propose an energy efficient multi-path routing algorithm based on foraging nature of ant colonies. This paper considers many meta-heuristic factors to provide good robust paths from source node to destination node in a hope to overcome the challenges posed by resource-constrained sensors. The performance of proposed ant colony routing algorithm is compared against well-known AODV routing protocol.
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    Toward Network-based DDoS Detection in Software-defined Networks
    (ACM, 2018) Jevtic, Stefan; Lotfalizadeh, Hamidreza; Kim, Dongsoo S.; Electrical and Computer Engineering, School of Engineering and Technology
    To combat susceptibility of modern computing systems to cyberattack, identifying and disrupting malicious traffic without human intervention is essential. To accomplish this, three main tasks for an effective intrusion detection system have been identified: monitor network traffic, categorize and identify anomalous behavior in near real time, and take appropriate action against the identified threat. This system leverages distributed SDN architecture and the principles of Artificial Immune Systems and Self-Organizing Maps to build a network-based intrusion detection system capable of detecting and terminating DDoS attacks in progress.