Recent advances in mobile networks have led to many new protocols, specifically in multi-hop wire... more Recent advances in mobile networks have led to many new protocols, specifically in multi-hop wireless networks including DTNs and sensor networks. We believe it is crucial to evaluate these new protocols and their services in a realistic environment. Towards realizing this goal, this paper proposes a mobile testbed consisting of two main elements: Robots with human-encounter behavior and participatory sensing utilizing crowd-sourcing. Personality of robots is built upon extensive analysis of wireless traces. By including participatory sensing into our framework, we intend to bridge the gap between controlled and uncontrolled environments and foster the scalability of our testbed.
An encounter-based network is a frequently-disconnected wireless ad-hoc network requiring nearby ... more An encounter-based network is a frequently-disconnected wireless ad-hoc network requiring nearby neighbors to store and forward data utilizing mobility and encounters over time. Using traditional approaches such as gateways or firewalls for deterring worm propagation in encounter-based networks is inappropriate. We propose models for the worm interaction approach that relies upon automated beneficial worm generation to alleviate problems of worm propagation in such networks. We study and analyze the impact of key mobile node characteristics including node cooperation, immunization, on-off behavior on the worm propagations and interactions. We validate our proposed model using extensive simulations. We also find that, in addition to immunization, cooperation can reduce the level of worm infection. Furthermore, on-off behavior linearly impacts only timing aspect but not the overall infection. Using realistic mobile network measurements, we find that encounters are non-uniform, the tre...
Force (IETF), its Areas, and its Working Groups. (Note that other groups may also distribute work... more Force (IETF), its Areas, and its Working Groups. (Note that other groups may also distribute working documents as Internet Drafts). Internet Drafts are draft documents valid for a maximum of six months. Internet Drafts may be updated, replaced, or obsoleted by other documents at any time. It is not appropriate to use Internet Drafts as reference material or to cite them other than as a \working draft" or \work in progress." Please check the I-D abstract listing contained in each Internet Draft directory to learn the current status of this or any other Internet Draft.
Encounter-based network is a frequently- disconnected wireless ad-hoc network requiring immediate... more Encounter-based network is a frequently- disconnected wireless ad-hoc network requiring immediate neighbors to store and forward aggregated data for information disseminations. Using traditional approaches such as gateways or firewalls for deterring worm propagation in encounter-based networks is inappropriate. Because this type of network is highly dynamic and has no specific boundary, we need a fully distributed security response mechanism. We propose the worm interaction approach that relies upon automated beneficial worm generation aiming to alleviate problems of worm propagations in such networks. This work is motivated by the 'War of the Worms' of the Internet worms between competing worms such as NetSky, Bagle and MyDoom. To understand the dynamic of worm interactions and its performance, we mathematically model several classes of worms and interactions using ordinary differential equations and analyze their behaviors.
Usage of mobile wireless Internet has grown very fast in recent years. This radical change in ava... more Usage of mobile wireless Internet has grown very fast in recent years. This radical change in availability of Internet has led to communication of big amount of data over mobile networks and consequently new challenges and opportunities for modeling of mobile Internet characteristics. While the traditional approach toward network modeling suggests finding a generic traffic model for the whole network, in this paper, we show that this approach does not capture all the dynamics of big mobile networks and does not provide enough accuracy. Our case study based on a big dataset including billions of netflow records collected from a campus-wide wireless mobile network shows that user interests acquired based on accessed domains and visited locations as well as user behavioral groups have a significant impact on traffic characteristics of big mobile networks. For this purpose, we utilize a novel graph-based approach based on KS-test as well as a novel co-clustering technique. Our study sho...
Realistic modeling of vehicular mobility has been particularly challenging due to a lack of large... more Realistic modeling of vehicular mobility has been particularly challenging due to a lack of large libraries of measurements in the research community. In this paper we introduce a novel method for large-scale monitoring, analysis, and identification of spatio-temporal models for vehicular mobility using the freely available online webcams in cities across the globe. We collect vehicular mobility traces from 2,700 traffic webcams in 10 different cities for several months and generate a mobility dataset of 7.5 Terabytes consisting of 125 million of images. To the best of our knowl- edge, this is the largest data set ever used in such study. To process and analyze this data, we propose an efficient and scalable algorithm to estimate traffic density based on background image subtraction. Initial results show that at least 82% of individual cameras with less than 5% deviation from four cities follow Loglogistic distribution and also 94% cameras from Toronto follow gamma distribution. The...
This document speciies the behavior of PIM-SM Multicast Border Routers (PMBRs) that connect PIM-S... more This document speciies the behavior of PIM-SM Multicast Border Routers (PMBRs) that connect PIM-SM to DVMRP networks, with DVMRP running in the Backbone, and PIM-SM running in leaf or transit networks. Force (IETF), its Areas, and its Working Groups. (Note that other groups may also distribute working documents as Internet Drafts). Internet Drafts are draft documents valid for a maximum of six months. Internet Drafts may be updated, replaced, or obsoleted by other documents at any time. It is not appropriate to use Internet Drafts as reference material or to cite them other than as a \working draft" or \work in progress." Please check the I-D abstract listing contained in each Internet Draft directory to learn the current status of this or any other Internet Draft.
Proceedings of the 17th ACM International Symposium on Mobility Management and Wireless Access, 2019
In emerging 5G wireless systems, Mobile Social Networks (MSN) will play an important role for pro... more In emerging 5G wireless systems, Mobile Social Networks (MSN) will play an important role for providing data services and offloading data traffic from cellular networks. MSNs are vulnerable to various security attacks because of the ways users move and collaborate. Since most protocols for MSNs are designed based on social behaviors of users, it is important to understand the impact of user behavior on network vulnerability. This can provide valuable insights into crucial factors, such as how easily a network loses its connectivity, or a network's ability to form strong communities. We present a novel vulnerability assessment and classification scheme based on structural, social and influence distribution metrics in mobile social networks. We design a vulnerability index metric (VI) to investigate the level of damage inflicted when networks are subjected to both targeted and random attacks. Then, we use influence distribution metrics and various machine learning based classifier...
We envision future mobile networks to be human-centric supporting interest-aware delivery, where ... more We envision future mobile networks to be human-centric supporting interest-aware delivery, where an interest maybe based on behavior, such as mobility pattern, location, or web browsing (or user profile) such as affiliation, attributes, or activity. An essential capability in future networks will be the ability to provide scalable group communication. Current communication paradigms, including unicast and multicast, require explicit identification of destination nodes (through node IDs or group membership protocols), while directory services translate logical, interest-specific queries into destination IDs where parties are then connected using interest-oblivious protocols. The power and scalability of such paradigms is quite limited in the context of future, highly dynamic mobile social networks, where it is desirable in many scenarios to support implicit membership based on interest. In such scenarios, membership in interest-groups is not explicitly expressed by users, it is rathe...
Two major factors affecting mobile network performance are mobility and traffic patterns. Simulat... more Two major factors affecting mobile network performance are mobility and traffic patterns. Simulations and analytical-based performance evaluations rely on models to approximate factors affecting the network. Hence, the understanding of mobility and traffic is imperative to the effective evaluation and efficient design of future mobile networks. Current models target either mobility or traffic, but do not capture their interplay. Many trace-based mobility models have largely used pre-smartphone datasets (e.g., AP-logs), or much coarser granularity (e.g., cell-towers) traces. This raises questions regarding the relevance of existing models, and motivates our study to revisit this area. In this study, we conduct a multidimensional analysis, to quantitatively characterize mobility and traffic spatio-temporal patterns, for laptops and smartphones, leading to a detailed integrated mobility-traffic analysis. Our study is data-driven, as we collect and mine capacious datasets (with 30TB, 30...
Force (IETF), its Areas, and its Working Groups. (Note that other groups may also distribute work... more Force (IETF), its Areas, and its Working Groups. (Note that other groups may also distribute working documents as Internet Drafts). Internet Drafts are draft documents valid for a maximum of six months. Internet Drafts may be updated, replaced, or obsoleted by other documents at any time. It is not appropriate to use Internet Drafts as reference material or to cite them other than as a \working draft" or \work in progress." Please check the I-D abstract listing contained in each Internet Draft directory to learn the current status of this or any other Internet Draft. Abstract This document describes the details of the PIM-SM 1, 2, 3] version 2 implementation for UNIX platforms; namely SunOS and SGI-IRIX. A generic kernel model is adopted, which is protocol independent , however some supporting functions are added to the kernel for encapsulation of data packets at user level and decapsulation of PIM Registers. Further, the basic model for the user level, PIM daemon (pimd), ...
In this paper, we compare various image background subtraction algorithms with the ground truth o... more In this paper, we compare various image background subtraction algorithms with the ground truth of cars counted. We have given a sample of thousand images, which are the snap shots of current traffic as records at various intersections and highways. We have also counted an approximate number of cars that are visible in these images. In order to ascertain the accuracy of algorithms to be used for the processing of million images, we compare them on many metrics that includes (i) Scalability (ii) Accuracy (iii) Processing time.
Understanding and predicting mobility are essential for the design and evaluation of future mobil... more Understanding and predicting mobility are essential for the design and evaluation of future mobile edge caching and networking. Consequently, research on prediction of human mobility has drawn significant attention in the last decade. Employing information-theoretic concepts and machine learning methods, earlier research has shown evidence that human behavior can be highly predictable. Despite existing studies, more investigations are needed to capture intrinsic mobility characteristics constraining predictability, and to explore more dimensions (e.g. device types) and spatio-temporal granularities, especially with the change in human behavior and technology. We analyze extensive longitudinal datasets with fine spatial granularity (AP level) covering 16 months. The study reveals device type as an important factor affecting predictability. Ultra-portable devices such as smartphones have "on-the-go" mode of usage (and hence dubbed "Flutes"), whereas laptops are &qu...
In large-scale wireless networks such as mobile ad hoc and sensor networks, efficient and robust ... more In large-scale wireless networks such as mobile ad hoc and sensor networks, efficient and robust service discovery and data-access mechanisms are bo th essential and challenging. Rendezvous-based mechanisms provide a valuable solution for provisio ning a wide range of services. In this paper, we de scribe R2D2 a novel scalable rendezvous-based architectu r for wireless networks. R2D2 is a general archite cture proposed for service location and bootstrapping in ad hoc networks, in addition to data-centric storag e, configuration, and task assignment in sensor networ ks. In R2D2 the network topology is divided into geographical regions, where each region is responsi ble for a set of keys representing the services or data of interest. Each key is mapped to a region based on a hash-table-like mapping scheme. A few elected node s inside each region are responsible for maintaining the map ped information. The service or data provider store s the information in the corresponding region and...
With the introduction of a newer generation of wireless devices and technologies, the need for an... more With the introduction of a newer generation of wireless devices and technologies, the need for an efficient architecture for IP mobility is becoming more apparent. Several architectures have been proposed to support IP mobility. Most studies, however, show that current architectures, in general, fall short from satisfying the performance requirements for wireless applications, mainly audio. Other studies have shown performance improvement by using multicast to reduce latency and packet loss during handoff. In this study, we propose a multicast-based architecture to support IP mobility. We evaluate our approach through simulation, and we compare it to mainstream approaches for IP mobility, mainly, the Mobile IP protocol. Comparison is performed according to the required performance criteria, such as smooth handoff and efficient routing. Our simulation results show significant improvement for the proposed architecture. On average, basic Mobile IP consumes almost twice as much network ...
Recent advances in mobile networks have led to many new protocols, specifically in multi-hop wire... more Recent advances in mobile networks have led to many new protocols, specifically in multi-hop wireless networks including DTNs and sensor networks. We believe it is crucial to evaluate these new protocols and their services in a realistic environment. Towards realizing this goal, this paper proposes a mobile testbed consisting of two main elements: Robots with human-encounter behavior and participatory sensing utilizing crowd-sourcing. Personality of robots is built upon extensive analysis of wireless traces. By including participatory sensing into our framework, we intend to bridge the gap between controlled and uncontrolled environments and foster the scalability of our testbed.
An encounter-based network is a frequently-disconnected wireless ad-hoc network requiring nearby ... more An encounter-based network is a frequently-disconnected wireless ad-hoc network requiring nearby neighbors to store and forward data utilizing mobility and encounters over time. Using traditional approaches such as gateways or firewalls for deterring worm propagation in encounter-based networks is inappropriate. We propose models for the worm interaction approach that relies upon automated beneficial worm generation to alleviate problems of worm propagation in such networks. We study and analyze the impact of key mobile node characteristics including node cooperation, immunization, on-off behavior on the worm propagations and interactions. We validate our proposed model using extensive simulations. We also find that, in addition to immunization, cooperation can reduce the level of worm infection. Furthermore, on-off behavior linearly impacts only timing aspect but not the overall infection. Using realistic mobile network measurements, we find that encounters are non-uniform, the tre...
Force (IETF), its Areas, and its Working Groups. (Note that other groups may also distribute work... more Force (IETF), its Areas, and its Working Groups. (Note that other groups may also distribute working documents as Internet Drafts). Internet Drafts are draft documents valid for a maximum of six months. Internet Drafts may be updated, replaced, or obsoleted by other documents at any time. It is not appropriate to use Internet Drafts as reference material or to cite them other than as a \working draft" or \work in progress." Please check the I-D abstract listing contained in each Internet Draft directory to learn the current status of this or any other Internet Draft.
Encounter-based network is a frequently- disconnected wireless ad-hoc network requiring immediate... more Encounter-based network is a frequently- disconnected wireless ad-hoc network requiring immediate neighbors to store and forward aggregated data for information disseminations. Using traditional approaches such as gateways or firewalls for deterring worm propagation in encounter-based networks is inappropriate. Because this type of network is highly dynamic and has no specific boundary, we need a fully distributed security response mechanism. We propose the worm interaction approach that relies upon automated beneficial worm generation aiming to alleviate problems of worm propagations in such networks. This work is motivated by the 'War of the Worms' of the Internet worms between competing worms such as NetSky, Bagle and MyDoom. To understand the dynamic of worm interactions and its performance, we mathematically model several classes of worms and interactions using ordinary differential equations and analyze their behaviors.
Usage of mobile wireless Internet has grown very fast in recent years. This radical change in ava... more Usage of mobile wireless Internet has grown very fast in recent years. This radical change in availability of Internet has led to communication of big amount of data over mobile networks and consequently new challenges and opportunities for modeling of mobile Internet characteristics. While the traditional approach toward network modeling suggests finding a generic traffic model for the whole network, in this paper, we show that this approach does not capture all the dynamics of big mobile networks and does not provide enough accuracy. Our case study based on a big dataset including billions of netflow records collected from a campus-wide wireless mobile network shows that user interests acquired based on accessed domains and visited locations as well as user behavioral groups have a significant impact on traffic characteristics of big mobile networks. For this purpose, we utilize a novel graph-based approach based on KS-test as well as a novel co-clustering technique. Our study sho...
Realistic modeling of vehicular mobility has been particularly challenging due to a lack of large... more Realistic modeling of vehicular mobility has been particularly challenging due to a lack of large libraries of measurements in the research community. In this paper we introduce a novel method for large-scale monitoring, analysis, and identification of spatio-temporal models for vehicular mobility using the freely available online webcams in cities across the globe. We collect vehicular mobility traces from 2,700 traffic webcams in 10 different cities for several months and generate a mobility dataset of 7.5 Terabytes consisting of 125 million of images. To the best of our knowl- edge, this is the largest data set ever used in such study. To process and analyze this data, we propose an efficient and scalable algorithm to estimate traffic density based on background image subtraction. Initial results show that at least 82% of individual cameras with less than 5% deviation from four cities follow Loglogistic distribution and also 94% cameras from Toronto follow gamma distribution. The...
This document speciies the behavior of PIM-SM Multicast Border Routers (PMBRs) that connect PIM-S... more This document speciies the behavior of PIM-SM Multicast Border Routers (PMBRs) that connect PIM-SM to DVMRP networks, with DVMRP running in the Backbone, and PIM-SM running in leaf or transit networks. Force (IETF), its Areas, and its Working Groups. (Note that other groups may also distribute working documents as Internet Drafts). Internet Drafts are draft documents valid for a maximum of six months. Internet Drafts may be updated, replaced, or obsoleted by other documents at any time. It is not appropriate to use Internet Drafts as reference material or to cite them other than as a \working draft" or \work in progress." Please check the I-D abstract listing contained in each Internet Draft directory to learn the current status of this or any other Internet Draft.
Proceedings of the 17th ACM International Symposium on Mobility Management and Wireless Access, 2019
In emerging 5G wireless systems, Mobile Social Networks (MSN) will play an important role for pro... more In emerging 5G wireless systems, Mobile Social Networks (MSN) will play an important role for providing data services and offloading data traffic from cellular networks. MSNs are vulnerable to various security attacks because of the ways users move and collaborate. Since most protocols for MSNs are designed based on social behaviors of users, it is important to understand the impact of user behavior on network vulnerability. This can provide valuable insights into crucial factors, such as how easily a network loses its connectivity, or a network's ability to form strong communities. We present a novel vulnerability assessment and classification scheme based on structural, social and influence distribution metrics in mobile social networks. We design a vulnerability index metric (VI) to investigate the level of damage inflicted when networks are subjected to both targeted and random attacks. Then, we use influence distribution metrics and various machine learning based classifier...
We envision future mobile networks to be human-centric supporting interest-aware delivery, where ... more We envision future mobile networks to be human-centric supporting interest-aware delivery, where an interest maybe based on behavior, such as mobility pattern, location, or web browsing (or user profile) such as affiliation, attributes, or activity. An essential capability in future networks will be the ability to provide scalable group communication. Current communication paradigms, including unicast and multicast, require explicit identification of destination nodes (through node IDs or group membership protocols), while directory services translate logical, interest-specific queries into destination IDs where parties are then connected using interest-oblivious protocols. The power and scalability of such paradigms is quite limited in the context of future, highly dynamic mobile social networks, where it is desirable in many scenarios to support implicit membership based on interest. In such scenarios, membership in interest-groups is not explicitly expressed by users, it is rathe...
Two major factors affecting mobile network performance are mobility and traffic patterns. Simulat... more Two major factors affecting mobile network performance are mobility and traffic patterns. Simulations and analytical-based performance evaluations rely on models to approximate factors affecting the network. Hence, the understanding of mobility and traffic is imperative to the effective evaluation and efficient design of future mobile networks. Current models target either mobility or traffic, but do not capture their interplay. Many trace-based mobility models have largely used pre-smartphone datasets (e.g., AP-logs), or much coarser granularity (e.g., cell-towers) traces. This raises questions regarding the relevance of existing models, and motivates our study to revisit this area. In this study, we conduct a multidimensional analysis, to quantitatively characterize mobility and traffic spatio-temporal patterns, for laptops and smartphones, leading to a detailed integrated mobility-traffic analysis. Our study is data-driven, as we collect and mine capacious datasets (with 30TB, 30...
Force (IETF), its Areas, and its Working Groups. (Note that other groups may also distribute work... more Force (IETF), its Areas, and its Working Groups. (Note that other groups may also distribute working documents as Internet Drafts). Internet Drafts are draft documents valid for a maximum of six months. Internet Drafts may be updated, replaced, or obsoleted by other documents at any time. It is not appropriate to use Internet Drafts as reference material or to cite them other than as a \working draft" or \work in progress." Please check the I-D abstract listing contained in each Internet Draft directory to learn the current status of this or any other Internet Draft. Abstract This document describes the details of the PIM-SM 1, 2, 3] version 2 implementation for UNIX platforms; namely SunOS and SGI-IRIX. A generic kernel model is adopted, which is protocol independent , however some supporting functions are added to the kernel for encapsulation of data packets at user level and decapsulation of PIM Registers. Further, the basic model for the user level, PIM daemon (pimd), ...
In this paper, we compare various image background subtraction algorithms with the ground truth o... more In this paper, we compare various image background subtraction algorithms with the ground truth of cars counted. We have given a sample of thousand images, which are the snap shots of current traffic as records at various intersections and highways. We have also counted an approximate number of cars that are visible in these images. In order to ascertain the accuracy of algorithms to be used for the processing of million images, we compare them on many metrics that includes (i) Scalability (ii) Accuracy (iii) Processing time.
Understanding and predicting mobility are essential for the design and evaluation of future mobil... more Understanding and predicting mobility are essential for the design and evaluation of future mobile edge caching and networking. Consequently, research on prediction of human mobility has drawn significant attention in the last decade. Employing information-theoretic concepts and machine learning methods, earlier research has shown evidence that human behavior can be highly predictable. Despite existing studies, more investigations are needed to capture intrinsic mobility characteristics constraining predictability, and to explore more dimensions (e.g. device types) and spatio-temporal granularities, especially with the change in human behavior and technology. We analyze extensive longitudinal datasets with fine spatial granularity (AP level) covering 16 months. The study reveals device type as an important factor affecting predictability. Ultra-portable devices such as smartphones have "on-the-go" mode of usage (and hence dubbed "Flutes"), whereas laptops are &qu...
In large-scale wireless networks such as mobile ad hoc and sensor networks, efficient and robust ... more In large-scale wireless networks such as mobile ad hoc and sensor networks, efficient and robust service discovery and data-access mechanisms are bo th essential and challenging. Rendezvous-based mechanisms provide a valuable solution for provisio ning a wide range of services. In this paper, we de scribe R2D2 a novel scalable rendezvous-based architectu r for wireless networks. R2D2 is a general archite cture proposed for service location and bootstrapping in ad hoc networks, in addition to data-centric storag e, configuration, and task assignment in sensor networ ks. In R2D2 the network topology is divided into geographical regions, where each region is responsi ble for a set of keys representing the services or data of interest. Each key is mapped to a region based on a hash-table-like mapping scheme. A few elected node s inside each region are responsible for maintaining the map ped information. The service or data provider store s the information in the corresponding region and...
With the introduction of a newer generation of wireless devices and technologies, the need for an... more With the introduction of a newer generation of wireless devices and technologies, the need for an efficient architecture for IP mobility is becoming more apparent. Several architectures have been proposed to support IP mobility. Most studies, however, show that current architectures, in general, fall short from satisfying the performance requirements for wireless applications, mainly audio. Other studies have shown performance improvement by using multicast to reduce latency and packet loss during handoff. In this study, we propose a multicast-based architecture to support IP mobility. We evaluate our approach through simulation, and we compare it to mainstream approaches for IP mobility, mainly, the Mobile IP protocol. Comparison is performed according to the required performance criteria, such as smooth handoff and efficient routing. Our simulation results show significant improvement for the proposed architecture. On average, basic Mobile IP consumes almost twice as much network ...
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Papers by Ahmed Helmy