Predicting students' performance during their years of academic study has been investigated treme... more Predicting students' performance during their years of academic study has been investigated tremendously. It offers important insights that can help and guide institutions to make timely decisions and changes leading to better student outcome achievements. In the post-COVID-19 pandemic era, the adoption of e-learning has gained momentum and has increased the availability of online related learning data. This has encouraged researchers to develop machine learning (ML)-based models to predict students' performance during online classes. The study presented in this paper, focuses on predicting student performance during a series of online interactive sessions by considering a dataset collected using digital electronics education and design suite. The dataset tracks the interaction of students during online lab work in terms of text editing, a number of keystrokes, time spent in each activity, etc., along with the exam score achieved per session. Our proposed prediction model consists of extracting a total of 86 novel statistical features, which were semantically categorized in three broad categories based on different criteria: (1) activity type, (2) timing statistics, and (3) peripheral activity count. This set of features were further reduced during the feature selection phase and only influential features were retained for training purposes. Our proposed ML model aims to predict whether a student's performance will be low or high. Five popular classifiers were used in our study, namely: random forest (RF), support vector machine, Naïve Bayes, logistic regression, and multilayer perceptron. We evaluated our model under three different scenarios: (1) 80:20 random data split for training and testing, (2) fivefold cross-validation, and (3) train the model on all sessions but one which will be used for testing. Results showed that our model achieved the best classification accuracy performance of 97.4% with the RF classifier. We demonstrated that, under similar experimental setup, our model outperformed other existing studies.
GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489), 2003
This work focuses on the Routing and Wavelength Assignment (RWA) problem in all-optical DWDM netw... more This work focuses on the Routing and Wavelength Assignment (RWA) problem in all-optical DWDM networks with Sparse Wavelength Conversion (SWC) capabilities. By sparse wavelength conversion, we mean that nodes within the optical network domain might or might not support optical wavelength conversion. For these nodes that support optical wavelength conversion, the number of wavelength converters might be limited. As such, optical lightpaths might or might not be able to find the wavelength conversion resources that might be needed for it to be established. In this work, we present the RWA problem in all-optical WDWM networks with sparse wavelength conversion capabilities (RWA-SWC). We also provide Integer Linear Programming (ILP) formulation for Static Lightpath Establishment (SLE) in all-optical networks with sparse wavelength conversion capabilities. Finally, we propose a new opaque extension to the OSPF routing protocol to advertise wavelength usage and converter availability throughout the optical network domain.
GLOBECOM '05. IEEE Global Telecommunications Conference, 2005., 2005
ABSTRACT cdma2000 1xEV-DV has been proposed as one of the standards for the next generation multi... more ABSTRACT cdma2000 1xEV-DV has been proposed as one of the standards for the next generation multimedia wireless generation (MWG) systems, which adopts new techniques such as adaptive modulation and coding (AMC) schemes to enhance wireless data services. Although many possible combinations of system parameters have been specified in the current 1xEV-DV standard, there is no further specification on how to dynamically choose the optimal combination of system parameters, such as the number of Walsh codes, the number of time slots, the modulation scheme, and the channel data rate, according to variations of buffer usage and channel quality. In this paper, we first review the latest cdma2000 1xEV-DV standard focusing on its unique features. Then, we propose a new delay-bounded dynamic resource allocation scheme for the QoS provisioning in cdma2000 1xEV-DV networks. The proposed scheme supports dynamic resource allocation by selecting the optimal combination of system parameters to satisfy the QoS requirements imposed by user applications, based on not only the channel quality but also the queue length. Simulation results show the proposed resource allocation scheme can provide delay-bounded services to multimedia applications such as voice and video.
2013 9th International Wireless Communications and Mobile Computing Conference (IWCMC), 2013
The Internet today continues to be vulnerable to distributed denial of service (DDoS) attacks. We... more The Internet today continues to be vulnerable to distributed denial of service (DDoS) attacks. We consider the design of a scalable agent-based system for collecting information about the structure and dynamics of DDoS attacks. Our system requires placement of agents on inter-autonomous system (AS) links in the Internet. The agents implement a self-organizing and totally decentralized mechanism capable of reconstructing topological information about the spatial and temporal structure of attacks. The system is effective at recovering DDoS attack structure, even at moderate levels of deployment.
2013 5th International Conference on Modeling, Simulation and Applied Optimization (ICMSAO), 2013
ABSTRACT Hospital care facilities often make use of noninteroperable devices produced by many dif... more ABSTRACT Hospital care facilities often make use of noninteroperable devices produced by many different vendors to monitor the state of patients. The heterogeneity of these devices makes it difficult to synthesize multivariate monitoring data into a unified array of real-time information regarding the state of patients in a care unit. Without an infrastructure for data integration, the assignment of caregivers to patients cannot be optimized to reflect the relative urgency of patient needs. This is an especially serious issue in critical care units (CCU). In this work, we evaluate the hypothesis that the integration of vital sign data can yield a significant positive impact on the efficiency and outcomes of critical care delivery, via a computer simulation of a CCU. Within our simulated CCU, an infinitely replenishable finite set of patients are being monitored, while a small set of caregivers is addressing patient alarm conditions. Patients who experience an alarm accumulate injury exponentially during the time that they are without care. Once a caregiver arrives at a patient, the time it takes to treat the underlying disturbance is assumed linear in the patient's accumulated injury. If a patient accumulates more than a threshold level of injury, a fatality occurs. Fatalities require the execution of close out procedures, which take a specified period of time (and must be given precedence over living patients). Through simulation we compare the current defacto scheduling processes in use within CCUs, against a new scheduling algorithm that makes use of an integrated array of patient information collected by a hypothetical vital sign integration infrastructure. Our simulation study provides quantitative evidence from which we can measure the extent to which such an infrastructure reduces risk to CCU patients and lowers operational personnel costs.
Proceedings of the 2007 international conference on Wireless communications and mobile computing - IWCMC '07, 2007
Rapid-deployment mobile ad-hoc networks (MANETs) are frequently characterized by common over-arch... more Rapid-deployment mobile ad-hoc networks (MANETs) are frequently characterized by common over-arching mission objectives which predicate a cooperativeness on the part of constituent nodes. In this article we present a new strategy to improve MANET communications based on node cooperation with respect to mobility. We present our model for cooperative mobility, and use this cost-benefit framework to explore the impact of cooperation in MANETs where nodes are-to varying extents-willing to be moved for the common good. We develop an effective centralized algorithm for mobility planning based on multigrid techniques. Our simulation results are compelling and demonstrate that the communication infrastructure-specifically, connection bit error rate-can be significantly improved by leveraging this proposed scheme.
Proceeding of the 2006 international conference on Communications and mobile computing - IWCMC '06, 2006
In this paper we present and evaluate a new technique to lower packet-level error rates of applic... more In this paper we present and evaluate a new technique to lower packet-level error rates of application layer connections in wireless ad-hoc networks. In our scheme, data packets submitted at a connection's source are checksummed and replicated, flowing breadth-first across an overlay network towards the destination. The destination delivers the first error-free copy of each packet, in order, to the application layer, dropping packets that are corrupt or duplicate. Specifically in this paper, we consider overlays consisting of multiple parallel multi-hop paths. We provide an algorithm which determines the optimal parameters of the overlay in terms of the number of paths, their lengths, and specific routes. We demonstrate experimentally that the proposed scheme significantly outperforms traditional routing and power allocation approaches in terms of bit error rate, even when the comparison is made under identical power consumption constraints.
2013 9th International Wireless Communications and Mobile Computing Conference (IWCMC), 2013
ABSTRACT One of the ways that malware infects is by exploiting weaknesses in computer systems, of... more ABSTRACT One of the ways that malware infects is by exploiting weaknesses in computer systems, often through conditions in software. When this happens, software and operating system vendors must repair these vulnerabilities by patching their software. However, vendors can release patches but cannot force users to apply them. Malware attempts to proliferate without regard to the state of the infected system; it is only once that the malware infection is stopped that we can truly say that systems are patched to eliminate that exploit. By examining appearance and disappearance of malware types, as determined through dynamic analysis of malware samples, classified by behavioral profiles correlated with a timeline of discovery dates, we can determine a more real-world average time for effective patch times, as opposed to the time it takes for a vendor to release a patch for a discovered vulnerability.
We present the results of simulation experiments that compare end-to-end error management (used i... more We present the results of simulation experiments that compare end-to-end error management (used in controlled access MAC protocols) against hop-by-hop error management (used in random access MAC protocols). Our experiments are novel in that we restrict both MAC schemes to identical power budgets and power distribution strategies. By making such a normalized comparison, we observe that end-to-end schemes are more effective than hop-by-hop schemes at reducing connection BER. We are also able to quantify the sensitivity of this relative advantage to various environmental parameters, including power budget size, geographic distance, the number of hops, and power distribution scheme.
In this paper we present new energy-aware techniques to lower the packetlevel error rates of appl... more In this paper we present new energy-aware techniques to lower the packetlevel error rates of application-layer connections in wireless ad-hoc networks. We consider a model in which each connection is allocated a fixed power budget, and ask: Is it better to use this power budget to send many duplicate packets (at lower power) or fewer (e.g. just one) packets (at high power)? We consider a scheme in which each application-layer connection is implemented at the physical level by an overlay network consisting of multiple parallel multi-hop paths. Data packets submitted at the connection source are checksummed and replicated, flowing breadth-first across the overlay network towards the destination. The destination delivers the first error-free copy of each packet, in order, to the application layer, dropping packets that are corrupt or duplicate. We compare this overlay scheme with the traditional scheme in which the source transmits precisely one packet to the destination along a single minimum-hop path. We show that even when the two schemes are constrained by identical power consumption bounds, the overlay scheme can use duplication to attain significantly lower packet-level error rates in many common situations. We describe the relationship between packet error rate, the extent of duplication, and the lengths of the paths, and show that the qualitative nature of the relationships change significantly, depending on available power budget.
International Journal of Communication Systems, 2013
The tremendous power of graphics processing unit (GPU) computing relative to prior CPU-only archi... more The tremendous power of graphics processing unit (GPU) computing relative to prior CPU-only architectures presents new opportunities for efficient solutions of previously intractable large-scale optimization problems. Although most previous work in this field focused on scientific applications in the areas of medicine and physics, here we present a Compute Unified Device Architecture-based (CUDA) GPU solution to solve the topology control problem in hybrid radio frequency and free space optics wireless mesh networks by adapting and adjusting the transmission power and the beam-width of individual nodes according to QoS requirements. Our approach is based on a stochastic global optimization technique inspired by the social behavior of flocking birds -so-called 'particle swarm optimization' -and was implemented on the NVIDIA GeForce GTX 285 GPU. The implementation achieved a performance speedup factor of 392 over a CPU-only implementation. Several innovations in the memory/execution structure in our approach enabled us to surpass all prior known particle swarm optimization GPU implementations. Our results provide a promising indication of the viability of GPU-based approaches towards the solution of large-scale optimization problems such as those found in radio frequency and free space optics wireless mesh network design.
IEEE Journal on Selected Areas in Communications, 2000
CDMA2000 1×EV-DV has been proposed as one of the global standards of third-generation (3G) networ... more CDMA2000 1×EV-DV has been proposed as one of the global standards of third-generation (3G) networks, which adopts TDM/CDM and adaptive modulation and coding (AMC) techniques to enhance the data rate. The current CDMA2000 1×EV-DV standard specifies all possible combinations of system parameters, but there is no any further specification in the standard on how to dynamically change the system parameters
In wavelength division multiplexing (WDM) networks, communication between optical cross-connect (... more In wavelength division multiplexing (WDM) networks, communication between optical cross-connect (OXC) switches takes place along all-optical WDM channels which are commonly referred to as lightpaths. This paper (i) describes the central algorithmic ...
Predicting students' performance during their years of academic study has been investigated treme... more Predicting students' performance during their years of academic study has been investigated tremendously. It offers important insights that can help and guide institutions to make timely decisions and changes leading to better student outcome achievements. In the post-COVID-19 pandemic era, the adoption of e-learning has gained momentum and has increased the availability of online related learning data. This has encouraged researchers to develop machine learning (ML)-based models to predict students' performance during online classes. The study presented in this paper, focuses on predicting student performance during a series of online interactive sessions by considering a dataset collected using digital electronics education and design suite. The dataset tracks the interaction of students during online lab work in terms of text editing, a number of keystrokes, time spent in each activity, etc., along with the exam score achieved per session. Our proposed prediction model consists of extracting a total of 86 novel statistical features, which were semantically categorized in three broad categories based on different criteria: (1) activity type, (2) timing statistics, and (3) peripheral activity count. This set of features were further reduced during the feature selection phase and only influential features were retained for training purposes. Our proposed ML model aims to predict whether a student's performance will be low or high. Five popular classifiers were used in our study, namely: random forest (RF), support vector machine, Naïve Bayes, logistic regression, and multilayer perceptron. We evaluated our model under three different scenarios: (1) 80:20 random data split for training and testing, (2) fivefold cross-validation, and (3) train the model on all sessions but one which will be used for testing. Results showed that our model achieved the best classification accuracy performance of 97.4% with the RF classifier. We demonstrated that, under similar experimental setup, our model outperformed other existing studies.
GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489), 2003
This work focuses on the Routing and Wavelength Assignment (RWA) problem in all-optical DWDM netw... more This work focuses on the Routing and Wavelength Assignment (RWA) problem in all-optical DWDM networks with Sparse Wavelength Conversion (SWC) capabilities. By sparse wavelength conversion, we mean that nodes within the optical network domain might or might not support optical wavelength conversion. For these nodes that support optical wavelength conversion, the number of wavelength converters might be limited. As such, optical lightpaths might or might not be able to find the wavelength conversion resources that might be needed for it to be established. In this work, we present the RWA problem in all-optical WDWM networks with sparse wavelength conversion capabilities (RWA-SWC). We also provide Integer Linear Programming (ILP) formulation for Static Lightpath Establishment (SLE) in all-optical networks with sparse wavelength conversion capabilities. Finally, we propose a new opaque extension to the OSPF routing protocol to advertise wavelength usage and converter availability throughout the optical network domain.
GLOBECOM '05. IEEE Global Telecommunications Conference, 2005., 2005
ABSTRACT cdma2000 1xEV-DV has been proposed as one of the standards for the next generation multi... more ABSTRACT cdma2000 1xEV-DV has been proposed as one of the standards for the next generation multimedia wireless generation (MWG) systems, which adopts new techniques such as adaptive modulation and coding (AMC) schemes to enhance wireless data services. Although many possible combinations of system parameters have been specified in the current 1xEV-DV standard, there is no further specification on how to dynamically choose the optimal combination of system parameters, such as the number of Walsh codes, the number of time slots, the modulation scheme, and the channel data rate, according to variations of buffer usage and channel quality. In this paper, we first review the latest cdma2000 1xEV-DV standard focusing on its unique features. Then, we propose a new delay-bounded dynamic resource allocation scheme for the QoS provisioning in cdma2000 1xEV-DV networks. The proposed scheme supports dynamic resource allocation by selecting the optimal combination of system parameters to satisfy the QoS requirements imposed by user applications, based on not only the channel quality but also the queue length. Simulation results show the proposed resource allocation scheme can provide delay-bounded services to multimedia applications such as voice and video.
2013 9th International Wireless Communications and Mobile Computing Conference (IWCMC), 2013
The Internet today continues to be vulnerable to distributed denial of service (DDoS) attacks. We... more The Internet today continues to be vulnerable to distributed denial of service (DDoS) attacks. We consider the design of a scalable agent-based system for collecting information about the structure and dynamics of DDoS attacks. Our system requires placement of agents on inter-autonomous system (AS) links in the Internet. The agents implement a self-organizing and totally decentralized mechanism capable of reconstructing topological information about the spatial and temporal structure of attacks. The system is effective at recovering DDoS attack structure, even at moderate levels of deployment.
2013 5th International Conference on Modeling, Simulation and Applied Optimization (ICMSAO), 2013
ABSTRACT Hospital care facilities often make use of noninteroperable devices produced by many dif... more ABSTRACT Hospital care facilities often make use of noninteroperable devices produced by many different vendors to monitor the state of patients. The heterogeneity of these devices makes it difficult to synthesize multivariate monitoring data into a unified array of real-time information regarding the state of patients in a care unit. Without an infrastructure for data integration, the assignment of caregivers to patients cannot be optimized to reflect the relative urgency of patient needs. This is an especially serious issue in critical care units (CCU). In this work, we evaluate the hypothesis that the integration of vital sign data can yield a significant positive impact on the efficiency and outcomes of critical care delivery, via a computer simulation of a CCU. Within our simulated CCU, an infinitely replenishable finite set of patients are being monitored, while a small set of caregivers is addressing patient alarm conditions. Patients who experience an alarm accumulate injury exponentially during the time that they are without care. Once a caregiver arrives at a patient, the time it takes to treat the underlying disturbance is assumed linear in the patient's accumulated injury. If a patient accumulates more than a threshold level of injury, a fatality occurs. Fatalities require the execution of close out procedures, which take a specified period of time (and must be given precedence over living patients). Through simulation we compare the current defacto scheduling processes in use within CCUs, against a new scheduling algorithm that makes use of an integrated array of patient information collected by a hypothetical vital sign integration infrastructure. Our simulation study provides quantitative evidence from which we can measure the extent to which such an infrastructure reduces risk to CCU patients and lowers operational personnel costs.
Proceedings of the 2007 international conference on Wireless communications and mobile computing - IWCMC '07, 2007
Rapid-deployment mobile ad-hoc networks (MANETs) are frequently characterized by common over-arch... more Rapid-deployment mobile ad-hoc networks (MANETs) are frequently characterized by common over-arching mission objectives which predicate a cooperativeness on the part of constituent nodes. In this article we present a new strategy to improve MANET communications based on node cooperation with respect to mobility. We present our model for cooperative mobility, and use this cost-benefit framework to explore the impact of cooperation in MANETs where nodes are-to varying extents-willing to be moved for the common good. We develop an effective centralized algorithm for mobility planning based on multigrid techniques. Our simulation results are compelling and demonstrate that the communication infrastructure-specifically, connection bit error rate-can be significantly improved by leveraging this proposed scheme.
Proceeding of the 2006 international conference on Communications and mobile computing - IWCMC '06, 2006
In this paper we present and evaluate a new technique to lower packet-level error rates of applic... more In this paper we present and evaluate a new technique to lower packet-level error rates of application layer connections in wireless ad-hoc networks. In our scheme, data packets submitted at a connection's source are checksummed and replicated, flowing breadth-first across an overlay network towards the destination. The destination delivers the first error-free copy of each packet, in order, to the application layer, dropping packets that are corrupt or duplicate. Specifically in this paper, we consider overlays consisting of multiple parallel multi-hop paths. We provide an algorithm which determines the optimal parameters of the overlay in terms of the number of paths, their lengths, and specific routes. We demonstrate experimentally that the proposed scheme significantly outperforms traditional routing and power allocation approaches in terms of bit error rate, even when the comparison is made under identical power consumption constraints.
2013 9th International Wireless Communications and Mobile Computing Conference (IWCMC), 2013
ABSTRACT One of the ways that malware infects is by exploiting weaknesses in computer systems, of... more ABSTRACT One of the ways that malware infects is by exploiting weaknesses in computer systems, often through conditions in software. When this happens, software and operating system vendors must repair these vulnerabilities by patching their software. However, vendors can release patches but cannot force users to apply them. Malware attempts to proliferate without regard to the state of the infected system; it is only once that the malware infection is stopped that we can truly say that systems are patched to eliminate that exploit. By examining appearance and disappearance of malware types, as determined through dynamic analysis of malware samples, classified by behavioral profiles correlated with a timeline of discovery dates, we can determine a more real-world average time for effective patch times, as opposed to the time it takes for a vendor to release a patch for a discovered vulnerability.
We present the results of simulation experiments that compare end-to-end error management (used i... more We present the results of simulation experiments that compare end-to-end error management (used in controlled access MAC protocols) against hop-by-hop error management (used in random access MAC protocols). Our experiments are novel in that we restrict both MAC schemes to identical power budgets and power distribution strategies. By making such a normalized comparison, we observe that end-to-end schemes are more effective than hop-by-hop schemes at reducing connection BER. We are also able to quantify the sensitivity of this relative advantage to various environmental parameters, including power budget size, geographic distance, the number of hops, and power distribution scheme.
In this paper we present new energy-aware techniques to lower the packetlevel error rates of appl... more In this paper we present new energy-aware techniques to lower the packetlevel error rates of application-layer connections in wireless ad-hoc networks. We consider a model in which each connection is allocated a fixed power budget, and ask: Is it better to use this power budget to send many duplicate packets (at lower power) or fewer (e.g. just one) packets (at high power)? We consider a scheme in which each application-layer connection is implemented at the physical level by an overlay network consisting of multiple parallel multi-hop paths. Data packets submitted at the connection source are checksummed and replicated, flowing breadth-first across the overlay network towards the destination. The destination delivers the first error-free copy of each packet, in order, to the application layer, dropping packets that are corrupt or duplicate. We compare this overlay scheme with the traditional scheme in which the source transmits precisely one packet to the destination along a single minimum-hop path. We show that even when the two schemes are constrained by identical power consumption bounds, the overlay scheme can use duplication to attain significantly lower packet-level error rates in many common situations. We describe the relationship between packet error rate, the extent of duplication, and the lengths of the paths, and show that the qualitative nature of the relationships change significantly, depending on available power budget.
International Journal of Communication Systems, 2013
The tremendous power of graphics processing unit (GPU) computing relative to prior CPU-only archi... more The tremendous power of graphics processing unit (GPU) computing relative to prior CPU-only architectures presents new opportunities for efficient solutions of previously intractable large-scale optimization problems. Although most previous work in this field focused on scientific applications in the areas of medicine and physics, here we present a Compute Unified Device Architecture-based (CUDA) GPU solution to solve the topology control problem in hybrid radio frequency and free space optics wireless mesh networks by adapting and adjusting the transmission power and the beam-width of individual nodes according to QoS requirements. Our approach is based on a stochastic global optimization technique inspired by the social behavior of flocking birds -so-called 'particle swarm optimization' -and was implemented on the NVIDIA GeForce GTX 285 GPU. The implementation achieved a performance speedup factor of 392 over a CPU-only implementation. Several innovations in the memory/execution structure in our approach enabled us to surpass all prior known particle swarm optimization GPU implementations. Our results provide a promising indication of the viability of GPU-based approaches towards the solution of large-scale optimization problems such as those found in radio frequency and free space optics wireless mesh network design.
IEEE Journal on Selected Areas in Communications, 2000
CDMA2000 1×EV-DV has been proposed as one of the global standards of third-generation (3G) networ... more CDMA2000 1×EV-DV has been proposed as one of the global standards of third-generation (3G) networks, which adopts TDM/CDM and adaptive modulation and coding (AMC) techniques to enhance the data rate. The current CDMA2000 1×EV-DV standard specifies all possible combinations of system parameters, but there is no any further specification in the standard on how to dynamically change the system parameters
In wavelength division multiplexing (WDM) networks, communication between optical cross-connect (... more In wavelength division multiplexing (WDM) networks, communication between optical cross-connect (OXC) switches takes place along all-optical WDM channels which are commonly referred to as lightpaths. This paper (i) describes the central algorithmic ...
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Papers by Ghassen Brahim