Abstract:-In this paper we describe a voxel-based 3-D reconstruction algorithm from multiple cali... more Abstract:-In this paper we describe a voxel-based 3-D reconstruction algorithm from multiple calibrated camera views. Unlike image-based algorithms, this algorithm is capable of detecting occlusion explicitly, and recovering the conventional Stereo Algorithms limitations; the algorithm is extendable to reconstruct the full surface without any restrictions on the cameras distribution. Because of using stable features at consistency checking the mismatching probability is decreased. The Grid Space is traced one time only; hence, ...
4th IEEE International Conference on Cloud Computing Technology and Science Proceedings, 2012
Recently, the advance of cloud computing services has attracted many customers to host their Inte... more Recently, the advance of cloud computing services has attracted many customers to host their Internet applications in the cloud. Infrastructure as a Service (IaaS) is on top of these services where it gives more control over the provisioned resources. The control is based on online monitoring of specific metrics (e.g., CPU, Memory, and Network). Despite the fact that these metrics guide resources provisioning, the lack of understanding application behavior can lead to wrong decisions. Moreover, current monitored metrics alone do not help in resources contention prediction, which is very common in shared infrastructures like IaaS. Nevertheless, the architecture of Internet applications, as multi-tier systems, makes contention prediction more complex while its influence can migrate from one tier to another. In this paper, we propose a pro-active global controller not only for dynamic resources provisioning, but also for predicting and eliminating contentions in multi-tier applications. Our technique combines monitored metrics, which are provided by current IaaS providers, with models that are built depending on the Internet applications profiling. The fitness of the monitored metrics to the application model is used for contention prediction. We examined our technique using RUBiS benchmark. The results express the efficiency of the developed algorithms in maintaining Internet applications performance even in shared infrastructures.
Communications in Computer and Information Science, 2012
Elasticity is one of the distinguishing characteristics associated with Cloud computing emergence... more Elasticity is one of the distinguishing characteristics associated with Cloud computing emergence. It enables cloud resources to auto-scale to cope with workload demand. Multi-instances horizontal scaling is the common scalability architecture in Cloud; however, its current implementation is coarse-grained, while it considers Virtual Machine (VM) as a scaling unit, this implies additional scaling-out overhead and limits it to specific applications. To overcome these limitations, we propose Elastic VM as a fine-grained vertical scaling architecture. Our results proved that Elastic VM architecture implies less consumption of resources, mitigates Service Level Objectives (SLOs) violation, and avoids scaling-up overhead. Furthermore, it scales broader range of applications including databases.
Proceedings of the ACM/SPEC international conference on International conference on performance engineering - ICPE '13, 2013
Energy management has become a significant concern in data centers to reduce operational costs an... more Energy management has become a significant concern in data centers to reduce operational costs and maintain systems' reliability. Using virtualization allows server consolidation, which increases server utilization and reduces energy consumption by turning off unused servers. However, server consolidation and turning off servers can cause also consequences if they are not exploited efficiently. For instance, many researchers consider a deterministic demand for capacity planning, but the demand is always subject to uncertainty. This uncertainty is an outcome of the workload prediction and the workload fluctuation. This paper presents a robust optimization for proactive capacity planning. We do not presume that the demand of VMs is deterministic. Thus, we implement a range prediction approach instead of a single point prediction. Then, we implement a robust optimization model exploiting the range-based prediction to determine the number of active servers for each capacity planning period. The results of the simulation show that our approach can mitigate undesirable changes in the powerstate of the servers. Additionally, the results indicate an increase in the servers' availability for hosting new VMs and reliability against a system failure during power-state changes. As future work, we intend to apply our approach to dynamic workload such as a web application. We plan to investigate applying our approach to other resources, where we consider only the CPU demand of VMs. Finally, we compare our approach against the approaches using stochastic optimization.
2009 International Conference for Internet Technology and Secured Transactions, (ICITST), 2009
The rapid burst of Internet usage and the corresponding growth of security risks and online attac... more The rapid burst of Internet usage and the corresponding growth of security risks and online attacks for the everyday user or the enterprise employee have emerged the terms Awareness Creation and Information Security Culture. Nevertheless, security education widely has remained an academic issue. Teaching system or network security on the basis of practical experience inherits a great challenge for the teaching environment, which is traditionally solved using a computer laboratory at a university campus. The Tele-Lab project offers a system for hands-on IT security training within a remote virtual lab environment-over the web, accessible by everyone. Such a system is inherently exposed to various security threats, since it has to provide full access to virtual machines running attack tools for potentially malicious users. The paper at hand introduces usage, management and operation of Tele-Lab as well as its architecture. Furthermore, this work focuses on possible attacks, the challenges when securing such a system, and shows how to set up an infrastructure that ensures the main security objectives identified as authentication, authorisation and availability.
Rapid growth of E-Business and frequent changes in websites contents as well as customers' intere... more Rapid growth of E-Business and frequent changes in websites contents as well as customers' interest make it difficult to predict workload surge. To maintain a good quality of service (QoS), system administrators must provision enough resources to cope with workload fluctuations considering that resources over-provisioning reduces business profits while under-provisioning degrades performance. In this paper, we present elastic system architecture for dynamic resources management and applications optimization in virtualized environment. In our architecture, we have implemented three controllers for CPU, Memory, and Application. These controllers run in parallel to guarantee efficient resources allocation and optimize application performance on co-hosted VMs dynamically. We evaluated our architecture with extensive experiments and several setups; the results show that considering online optimization of application, with dynamic CPU and Memory allocation, can reduce service level objectives (SLOs) violation and maintain application performance.. .
At Hasso Plattner Institute (HPI), I had the opportunity to meet many wonderful people. It is my ... more At Hasso Plattner Institute (HPI), I had the opportunity to meet many wonderful people. It is my pleasure to thank those who supported me to make this thesis possible. First and foremost, I would like to thank my Ph.D. supervisor, Prof. Dr. Christoph Meinel, for his continues support. In spite of his tight schedule, he always found the time to discuss, guide, and motivate my research ideas. The thanks are extended to Dr. Karin-Irene Eiermann for assisting me even before moving to Germany. I am also grateful for Michaela Schmitz. She managed everything well to make everyones life easier. I owe a thanks to Dr. Nemeth Sharon for helping me to improve my English writing skills. My friends and office mates Raja and Christian, it was a nice time that we spent together. I am thankful for every German word or piece of knowledge you had passed to me. Cycling to HPI was enjoyable and helped me to start nice and productive days. Matthias, Franka, Birgit and Haojin; it was always enjoyable chatting with you. Lutz, thanks for the tiny breaks that helped refreshing mind and continuing work. Aaron, Amir, Xiaoyin and Feng; the after-work basketball and football games were a must to get rid of the daily stress. Ahmed, Eyad, Ibrahim and Nuhad; I will miss our late nights in the coffee shop discussing everybodys research ideas, exchanging experience, and supporting each other. I owe a lot to my family Mum, Dad, and my wife Safaa for her love, trusts, and support especially at hard moments. Definitions Scale out: To scale out (scale horizontally) is to add more nodes to the system. An example might be adding more web instances to web tier. Scale up: To scale up (scale vertically) is to add resources to the same node in a system. An example might be to add more physical memory (i.e., RAM) to a database node. Scale down: To scale down is to release some acquired resources, either by releasing some nodes or by removing some of the node's resources. Scalable architecture: It is an architecture enables the Internet application to scale rapidly, automatically, and transparently. Service Level Agreement (SLA): SLA is an agreement outlining a specific service commitment made between contract parties-a service provider and its customer. The agreement describes the overall service, support details, financial aspects of service delivery, penalties, terms and conditions, and performance metrics that govern service delivery. Service Level Objective (SLO): SLO is specific measurable characteristic of the SLA such as availability, throughput, response time, or quality. An example of response time as an objective is: "95% of the requests to an Internet application should be answered in less than 100 milliseconds measured over 24 hours". On premises infrastructure: It is an infrastructure hosted in the facility of an organization, such as a university datacenter hosted within the university buildings. Off premises infrastructure: It is an infrastructure hosted in the facility of another organization, such as the public cloud provided by Amazon EC2.
2012 IEEE International Conference on Green Computing and Communications, 2012
ABSTRACT Cloud computing is a consolidation environment that hosts heterogeneous applications. Cu... more ABSTRACT Cloud computing is a consolidation environment that hosts heterogeneous applications. Currently, clouds use virtualization technologies to provide an isolated execution environment and agile resource provisioning. Furthermore, live migration is widely exploited to achieve energy saving. However, consolidation and live migration can cause resource contention and utilization overhead that influence application performance. In this paper, we implement a network model and a memory subsystem model into CloudSim simulator. Then, we present a thorough analysis of the High Performance Computing NPB suite including memory bandwidth demand, communication patterns between processes, and migration overhead. To study the performance of the NPB Benchmark suite, we simulate the behaviour of these benchmarks including multi-thread com-munication via shared memory, multi-process communication via network. Thus, this allows implementing efficient VMs scheduling and resource provisioning policies. The results show that using CPU utilization as a trigger to perform management action such as VM migration is misleading and might aggravate application performance. Furthermore, we present a power model including the utilization of CPU, memory-bus, and network. This model provides a precise estimation of power consumption.
2012 IEEE Fifth International Conference on Cloud Computing, 2012
Traditionally, Infrastructure as a Service (IaaS) providers deliver their services as Reserved or... more Traditionally, Infrastructure as a Service (IaaS) providers deliver their services as Reserved or On-Demand instances. Spot Instances (SIs) is a complementary service that allows customers to bid on the free capacity at the provider data centers. Therefore, the decrease in the free capacity may result in terminating instances abruptly. To ensure fair trading, the provider does not charge customers for the interrupted partial hours. However, SIs price history traces analysis shows that uncharged time could rise up to 30% of the instance total run time, which means a reduction in the provider's profit. In this paper, we propose Elastic Spot Instances (ESIs) approach. It is a trade-off between the price and the total run time, where instead of abruptly terminating the SIs, the provider scales down their capacity proportionally to the increase in the price. Our approach delegates the task of interrupting the instances into the customers, but at the same time keeps the control on the provider side to isolate SIs' impact on the other services at overloaded time. Our approach doesn't imply an additional overhead or complex modification to current IaaS, while it consumes interfaces that are available by most of nowadays virtualization technologies.
... of the elasticity Figure 2. Ela e load balan Monitoring ( of the VM es seen abov or a long ti... more ... of the elasticity Figure 2. Ela e load balan Monitoring ( of the VM es seen abov or a long ti it has the s real bottlene ent way, inst umption (eg resources to ccompanied mically to sa M more aware ... ver has a du Xen 3.3 with 1, Linux Ub rsion 2.2.11) rk (ab) [4], th the concur ...
Abstract. Xen is widely used to implement cloud computing, by providing third parties with root a... more Abstract. Xen is widely used to implement cloud computing, by providing third parties with root access to domains. In such scenarios, it is crucial that attackers cannot affect other domains or Xen itself. However, Wojtczuk demonstrated how to install a root kit in case an attacker has root access to a privileged domain. Yet, this attack has not been ported to current Xen and Linux versions. We extended it and made it applicable to newer Xen and Linux kernel versions. Also, we integrated the attack into the Metsploit framework. ...
Abstract: Traditionally, Infrastructure as a Service (IaaS) providers deliver their services as R... more Abstract: Traditionally, Infrastructure as a Service (IaaS) providers deliver their services as Reserved or On-Demand instances. Spot Instances (SIs) is a complementary service that allows customers to bid on the free capacity in the provider data centers. Therefore, the decrease in the free capacity may result in terminating instances abruptly. To ensure fair trading, the provider does not charge customers for the interrupted partial hours. However, our experiments show that uncharged time could rise up to 30% of the instance total run ...
Proceedings of the 2011 International Conference on Parallel and Distributed Processing Techniques and Applications (PDPTA 2011), Jul 1, 2011
Abstract—Heterogeneous multicore processors could be the future trend of processors' industr... more Abstract—Heterogeneous multicore processors could be the future trend of processors' industry due to their performance-power efficiency. In the operating systems domain, A heterogeneity-aware scheduler assigns a thread or an application to an appropriate core to realize this efficiency. Using virtualization technologies enables resource consolidation and achieves effective utilization of resources. Nevertheless, Hypervisors' scheduling-policy is based on the round robin algorithm to ensure fairness among VMs. Emerging ...
Abstract:-In this paper we describe a voxel-based 3-D reconstruction algorithm from multiple cali... more Abstract:-In this paper we describe a voxel-based 3-D reconstruction algorithm from multiple calibrated camera views. Unlike image-based algorithms, this algorithm is capable of detecting occlusion explicitly, and recovering the conventional Stereo Algorithms limitations; the algorithm is extendable to reconstruct the full surface without any restrictions on the cameras distribution. Because of using stable features at consistency checking the mismatching probability is decreased. The Grid Space is traced one time only; hence, ...
4th IEEE International Conference on Cloud Computing Technology and Science Proceedings, 2012
Recently, the advance of cloud computing services has attracted many customers to host their Inte... more Recently, the advance of cloud computing services has attracted many customers to host their Internet applications in the cloud. Infrastructure as a Service (IaaS) is on top of these services where it gives more control over the provisioned resources. The control is based on online monitoring of specific metrics (e.g., CPU, Memory, and Network). Despite the fact that these metrics guide resources provisioning, the lack of understanding application behavior can lead to wrong decisions. Moreover, current monitored metrics alone do not help in resources contention prediction, which is very common in shared infrastructures like IaaS. Nevertheless, the architecture of Internet applications, as multi-tier systems, makes contention prediction more complex while its influence can migrate from one tier to another. In this paper, we propose a pro-active global controller not only for dynamic resources provisioning, but also for predicting and eliminating contentions in multi-tier applications. Our technique combines monitored metrics, which are provided by current IaaS providers, with models that are built depending on the Internet applications profiling. The fitness of the monitored metrics to the application model is used for contention prediction. We examined our technique using RUBiS benchmark. The results express the efficiency of the developed algorithms in maintaining Internet applications performance even in shared infrastructures.
Communications in Computer and Information Science, 2012
Elasticity is one of the distinguishing characteristics associated with Cloud computing emergence... more Elasticity is one of the distinguishing characteristics associated with Cloud computing emergence. It enables cloud resources to auto-scale to cope with workload demand. Multi-instances horizontal scaling is the common scalability architecture in Cloud; however, its current implementation is coarse-grained, while it considers Virtual Machine (VM) as a scaling unit, this implies additional scaling-out overhead and limits it to specific applications. To overcome these limitations, we propose Elastic VM as a fine-grained vertical scaling architecture. Our results proved that Elastic VM architecture implies less consumption of resources, mitigates Service Level Objectives (SLOs) violation, and avoids scaling-up overhead. Furthermore, it scales broader range of applications including databases.
Proceedings of the ACM/SPEC international conference on International conference on performance engineering - ICPE '13, 2013
Energy management has become a significant concern in data centers to reduce operational costs an... more Energy management has become a significant concern in data centers to reduce operational costs and maintain systems' reliability. Using virtualization allows server consolidation, which increases server utilization and reduces energy consumption by turning off unused servers. However, server consolidation and turning off servers can cause also consequences if they are not exploited efficiently. For instance, many researchers consider a deterministic demand for capacity planning, but the demand is always subject to uncertainty. This uncertainty is an outcome of the workload prediction and the workload fluctuation. This paper presents a robust optimization for proactive capacity planning. We do not presume that the demand of VMs is deterministic. Thus, we implement a range prediction approach instead of a single point prediction. Then, we implement a robust optimization model exploiting the range-based prediction to determine the number of active servers for each capacity planning period. The results of the simulation show that our approach can mitigate undesirable changes in the powerstate of the servers. Additionally, the results indicate an increase in the servers' availability for hosting new VMs and reliability against a system failure during power-state changes. As future work, we intend to apply our approach to dynamic workload such as a web application. We plan to investigate applying our approach to other resources, where we consider only the CPU demand of VMs. Finally, we compare our approach against the approaches using stochastic optimization.
2009 International Conference for Internet Technology and Secured Transactions, (ICITST), 2009
The rapid burst of Internet usage and the corresponding growth of security risks and online attac... more The rapid burst of Internet usage and the corresponding growth of security risks and online attacks for the everyday user or the enterprise employee have emerged the terms Awareness Creation and Information Security Culture. Nevertheless, security education widely has remained an academic issue. Teaching system or network security on the basis of practical experience inherits a great challenge for the teaching environment, which is traditionally solved using a computer laboratory at a university campus. The Tele-Lab project offers a system for hands-on IT security training within a remote virtual lab environment-over the web, accessible by everyone. Such a system is inherently exposed to various security threats, since it has to provide full access to virtual machines running attack tools for potentially malicious users. The paper at hand introduces usage, management and operation of Tele-Lab as well as its architecture. Furthermore, this work focuses on possible attacks, the challenges when securing such a system, and shows how to set up an infrastructure that ensures the main security objectives identified as authentication, authorisation and availability.
Rapid growth of E-Business and frequent changes in websites contents as well as customers' intere... more Rapid growth of E-Business and frequent changes in websites contents as well as customers' interest make it difficult to predict workload surge. To maintain a good quality of service (QoS), system administrators must provision enough resources to cope with workload fluctuations considering that resources over-provisioning reduces business profits while under-provisioning degrades performance. In this paper, we present elastic system architecture for dynamic resources management and applications optimization in virtualized environment. In our architecture, we have implemented three controllers for CPU, Memory, and Application. These controllers run in parallel to guarantee efficient resources allocation and optimize application performance on co-hosted VMs dynamically. We evaluated our architecture with extensive experiments and several setups; the results show that considering online optimization of application, with dynamic CPU and Memory allocation, can reduce service level objectives (SLOs) violation and maintain application performance.. .
At Hasso Plattner Institute (HPI), I had the opportunity to meet many wonderful people. It is my ... more At Hasso Plattner Institute (HPI), I had the opportunity to meet many wonderful people. It is my pleasure to thank those who supported me to make this thesis possible. First and foremost, I would like to thank my Ph.D. supervisor, Prof. Dr. Christoph Meinel, for his continues support. In spite of his tight schedule, he always found the time to discuss, guide, and motivate my research ideas. The thanks are extended to Dr. Karin-Irene Eiermann for assisting me even before moving to Germany. I am also grateful for Michaela Schmitz. She managed everything well to make everyones life easier. I owe a thanks to Dr. Nemeth Sharon for helping me to improve my English writing skills. My friends and office mates Raja and Christian, it was a nice time that we spent together. I am thankful for every German word or piece of knowledge you had passed to me. Cycling to HPI was enjoyable and helped me to start nice and productive days. Matthias, Franka, Birgit and Haojin; it was always enjoyable chatting with you. Lutz, thanks for the tiny breaks that helped refreshing mind and continuing work. Aaron, Amir, Xiaoyin and Feng; the after-work basketball and football games were a must to get rid of the daily stress. Ahmed, Eyad, Ibrahim and Nuhad; I will miss our late nights in the coffee shop discussing everybodys research ideas, exchanging experience, and supporting each other. I owe a lot to my family Mum, Dad, and my wife Safaa for her love, trusts, and support especially at hard moments. Definitions Scale out: To scale out (scale horizontally) is to add more nodes to the system. An example might be adding more web instances to web tier. Scale up: To scale up (scale vertically) is to add resources to the same node in a system. An example might be to add more physical memory (i.e., RAM) to a database node. Scale down: To scale down is to release some acquired resources, either by releasing some nodes or by removing some of the node's resources. Scalable architecture: It is an architecture enables the Internet application to scale rapidly, automatically, and transparently. Service Level Agreement (SLA): SLA is an agreement outlining a specific service commitment made between contract parties-a service provider and its customer. The agreement describes the overall service, support details, financial aspects of service delivery, penalties, terms and conditions, and performance metrics that govern service delivery. Service Level Objective (SLO): SLO is specific measurable characteristic of the SLA such as availability, throughput, response time, or quality. An example of response time as an objective is: "95% of the requests to an Internet application should be answered in less than 100 milliseconds measured over 24 hours". On premises infrastructure: It is an infrastructure hosted in the facility of an organization, such as a university datacenter hosted within the university buildings. Off premises infrastructure: It is an infrastructure hosted in the facility of another organization, such as the public cloud provided by Amazon EC2.
2012 IEEE International Conference on Green Computing and Communications, 2012
ABSTRACT Cloud computing is a consolidation environment that hosts heterogeneous applications. Cu... more ABSTRACT Cloud computing is a consolidation environment that hosts heterogeneous applications. Currently, clouds use virtualization technologies to provide an isolated execution environment and agile resource provisioning. Furthermore, live migration is widely exploited to achieve energy saving. However, consolidation and live migration can cause resource contention and utilization overhead that influence application performance. In this paper, we implement a network model and a memory subsystem model into CloudSim simulator. Then, we present a thorough analysis of the High Performance Computing NPB suite including memory bandwidth demand, communication patterns between processes, and migration overhead. To study the performance of the NPB Benchmark suite, we simulate the behaviour of these benchmarks including multi-thread com-munication via shared memory, multi-process communication via network. Thus, this allows implementing efficient VMs scheduling and resource provisioning policies. The results show that using CPU utilization as a trigger to perform management action such as VM migration is misleading and might aggravate application performance. Furthermore, we present a power model including the utilization of CPU, memory-bus, and network. This model provides a precise estimation of power consumption.
2012 IEEE Fifth International Conference on Cloud Computing, 2012
Traditionally, Infrastructure as a Service (IaaS) providers deliver their services as Reserved or... more Traditionally, Infrastructure as a Service (IaaS) providers deliver their services as Reserved or On-Demand instances. Spot Instances (SIs) is a complementary service that allows customers to bid on the free capacity at the provider data centers. Therefore, the decrease in the free capacity may result in terminating instances abruptly. To ensure fair trading, the provider does not charge customers for the interrupted partial hours. However, SIs price history traces analysis shows that uncharged time could rise up to 30% of the instance total run time, which means a reduction in the provider's profit. In this paper, we propose Elastic Spot Instances (ESIs) approach. It is a trade-off between the price and the total run time, where instead of abruptly terminating the SIs, the provider scales down their capacity proportionally to the increase in the price. Our approach delegates the task of interrupting the instances into the customers, but at the same time keeps the control on the provider side to isolate SIs' impact on the other services at overloaded time. Our approach doesn't imply an additional overhead or complex modification to current IaaS, while it consumes interfaces that are available by most of nowadays virtualization technologies.
... of the elasticity Figure 2. Ela e load balan Monitoring ( of the VM es seen abov or a long ti... more ... of the elasticity Figure 2. Ela e load balan Monitoring ( of the VM es seen abov or a long ti it has the s real bottlene ent way, inst umption (eg resources to ccompanied mically to sa M more aware ... ver has a du Xen 3.3 with 1, Linux Ub rsion 2.2.11) rk (ab) [4], th the concur ...
Abstract. Xen is widely used to implement cloud computing, by providing third parties with root a... more Abstract. Xen is widely used to implement cloud computing, by providing third parties with root access to domains. In such scenarios, it is crucial that attackers cannot affect other domains or Xen itself. However, Wojtczuk demonstrated how to install a root kit in case an attacker has root access to a privileged domain. Yet, this attack has not been ported to current Xen and Linux versions. We extended it and made it applicable to newer Xen and Linux kernel versions. Also, we integrated the attack into the Metsploit framework. ...
Abstract: Traditionally, Infrastructure as a Service (IaaS) providers deliver their services as R... more Abstract: Traditionally, Infrastructure as a Service (IaaS) providers deliver their services as Reserved or On-Demand instances. Spot Instances (SIs) is a complementary service that allows customers to bid on the free capacity in the provider data centers. Therefore, the decrease in the free capacity may result in terminating instances abruptly. To ensure fair trading, the provider does not charge customers for the interrupted partial hours. However, our experiments show that uncharged time could rise up to 30% of the instance total run ...
Proceedings of the 2011 International Conference on Parallel and Distributed Processing Techniques and Applications (PDPTA 2011), Jul 1, 2011
Abstract—Heterogeneous multicore processors could be the future trend of processors' industr... more Abstract—Heterogeneous multicore processors could be the future trend of processors' industry due to their performance-power efficiency. In the operating systems domain, A heterogeneity-aware scheduler assigns a thread or an application to an appropriate core to realize this efficiency. Using virtualization technologies enables resource consolidation and achieves effective utilization of resources. Nevertheless, Hypervisors' scheduling-policy is based on the round robin algorithm to ensure fairness among VMs. Emerging ...
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Papers by Wesam Dawoud