Overlay networks monitoring

The phenomenal growth of the Internet and its entry into many aspects of daily life has led to a great dependency on its services. Multimedia and content distribution applications (e.g., video streaming, online gaming, VoIP) require Quality of Service (QoS) guarantees in terms of bandwidth, delay, loss, and jitter to maintain a certain level of performance. Moreover, E-commerce applications and retail websites are faced with increasing demand for better throughput and response time performance. The most practical way to realize such applications is through the use of overlay networks, which are logical networks that implement service and resource management functionalities at the application layer. Overlays offer better deployability, scalability, security, and resiliency properties than network layer based implementation of services. Network monitoring and routing are among the most important issues in the design and operation of overlay networks. Accurate monitoring of QoS parameters is a challenging problem due to: (i) unbounded link stress in the underlying IP network, and (ii) the conflict in measurements caused by spatial and temporal overlap among measurement tasks. In this context, the focus of this dissertation is on the design and evaluation of efficient QoS monitoring and fault location algorithms using overlay networks. First, the issue of monitoring accuracy provided by multiple concurrent active measurements is studied on a large-scale overlay test-bed (PlanetLab), the factors affecting the accuracy are identified, and the measurement conflict problem is introduced. Then, the problem of conducting conflict-free measurements is formulated as a scheduling problem of real-time tasks, its complexity is proven to be NP-hard, and efficient heuristic algorithms for the problem are proposed. Second, an algorithm for minimizing monitoring overhead while controlling the IP link stress is proposed. Finally, the use of overlay monitoring to locate IP links\u27 faults is investigated. Specifically, the problem of designing an overlay network for verifying the location of IP links\u27 faults, under cost and link stress constraints, is formulated as an integer generalized flow problem, and its complexity is proven to be NP-hard. An optimal polynomial time algorithm for the relaxed problem (relaxed link stress constraints) is proposed. A combination of simulation and experimental studies using real-life measurement tools and Internet topologies of major ISP networks is conducted to evaluate the proposed algorithms. The studies show that the proposed algorithms significantly improve the accuracy and link stress of overlay monitoring, while incurring low overheads. The evaluation of fault location algorithms show that fast and highly accurate verification of faults can be achieved using overlay monitoring. In conclusion, the holistic view taken and the solutions developed for network monitoring provide a comprehensive framework for the design, operation, and evolution of overlay networks

A rich learning lesson using the Poisson distribution

In this note, we explore the rich information about inference that the Poisson distribution has. The source of this information is mainly the fact that the mean and variance of this distribution are equal

Estimation Using Bivariate Extreme Ranked Set Sampling With Application To The Bivariate Normal Distribution

In this article, the procedure of bivariate extreme ranked set sampling (BVERSS) is introduced and investigated as a procedure of obtaining more accurate samples for estimating the parameters of bivariate populations. This procedure takes its strength from the advantages of bivariate ranked set sampling (BVRSS) over the usual ranked set sampling in dealing with two characteristics simultaneously, and the advantages of extreme ranked set sampling (ERSS) over usual RSS in reducing the ranking errors and hence in being more applicable. The BVERSS procedure will be applied to the case of the parameters of the bivariate normal distributions. Illustration using real data is also provided

On the 'independence of trials-assumption' in geometric distribution

In this note, it is shown through an example that the assumption of the independence of Bernoulli trials in the geometric experiment may unexpectedly not be satisfied. The example can serve as a suitable and useful classroom activity for students in introductory probability course

Feasibility Study of Noninvasive Tumor Treatment with Focused Ultrasound

Abstract This paper describes the design, construction, and evaluation of a three-dimensional (3D) ultrasound system to be used for tumor treatment using high-intensity focused ultrasound (HIFU). The system consists of two parts: an ultrasonic therapy part and a treatment planning part. The ultrasonic therapy part consists of an ultrasound bowl-shaped transducer made from lead zirconate titanate (PZT) and with a resonance frequency of 0.5 MHz. Electrical LC matching circuit built for maximum electrical power delivery to the transducer, a function generator, and a power amplifier. The ultrasonic therapy part is designed for generating a focus with high acoustical powers. The treatment planning part consists of three stepper motors (responsible for moving the setup in the x-y-and z-directions), three high-voltage high-current Darlington arrays (to supply the stepper motors with the required voltages and currents), and C# software to perform the treatment planning. To assess the movement of the treatment planner, each of the three stepper motors was moved forward and backward from end to end. Then the treatment planner was successfully driven to cover cubes of dimensions of 1 × 1 × 1 cm 3 , 2 × 2 × 2 cm 3 , 4 × 4 × 4 cm 3 , and 8 × 8 × 8 cm 3 , with step sizes 0.5 mm, 1 mm, 2 mm, and 4 mm, respectively. Ex vivo experiments were performed and indicated the capability of the system to generate lesions both on-and off-axis. Three different lesions, one on-axis and two off-axis, were successfully generated

Overlay networks monitoring

The phenomenal growth of the Internet and its entry into many aspects of daily life has led to a great dependency on its services. Multimedia and content distribution applications (e.g., video streaming, online gaming, VoIP) require Quality of Service (QoS) guarantees in terms of bandwidth, delay, loss, and jitter to maintain a certain level of performance. Moreover, E-commerce applications and retail websites are faced with increasing demand for better throughput and response time performance. The most practical way to realize such applications is through the use of overlay networks, which are logical networks that implement service and resource management functionalities at the application layer. Overlays offer better deployability, scalability, security, and resiliency properties than network layer based implementation of services. Network monitoring and routing are among the most important issues in the design and operation of overlay networks. Accurate monitoring of QoS parameters is a challenging problem due to: (i) unbounded link stress in the underlying IP network, and (ii) the conflict in measurements caused by spatial and temporal overlap among measurement tasks. In this context, the focus of this dissertation is on the design and evaluation of efficient QoS monitoring and fault location algorithms using overlay networks. First, the issue of monitoring accuracy provided by multiple concurrent active measurements is studied on a large-scale overlay test-bed (PlanetLab), the factors affecting the accuracy are identified, and the measurement conflict problem is introduced. Then, the problem of conducting conflict-free measurements is formulated as a scheduling problem of real-time tasks, its complexity is proven to be NP-hard, and efficient heuristic algorithms for the problem are proposed. Second, an algorithm for minimizing monitoring overhead while controlling the IP link stress is proposed. Finally, the use of overlay monitoring to locate IP links' faults is investigated. Specifically, the problem of designing an overlay network for verifying the location of IP links' faults, under cost and link stress constraints, is formulated as an integer generalized flow problem, and its complexity is proven to be NP-hard. An optimal polynomial time algorithm for the relaxed problem (relaxed link stress constraints) is proposed. A combination of simulation and experimental studies using real-life measurement tools and Internet topologies of major ISP networks is conducted to evaluate the proposed algorithms. The studies show that the proposed algorithms significantly improve the accuracy and link stress of overlay monitoring, while incurring low overheads. The evaluation of fault location algorithms show that fast and highly accurate verification of faults can be achieved using overlay monitoring. In conclusion, the holistic view taken and the solutions developed for network monitoring provide a comprehensive framework for the design, operation, and evolution of overlay networks.</p

On the Automatic Detection and Classification of Skin Cancer Using Deep Transfer Learning

Skin cancer (melanoma and non-melanoma) is one of the most common cancer types and leads to hundreds of thousands of yearly deaths worldwide. It manifests itself through abnormal growth of skin cells. Early diagnosis drastically increases the chances of recovery. Moreover, it may render surgical, radiographic, or chemical therapies unnecessary or lessen their overall usage. Thus, healthcare costs can be reduced. The process of diagnosing skin cancer starts with dermoscopy, which inspects the general shape, size, and color characteristics of skin lesions, and suspected lesions undergo further sampling and lab tests for confirmation. Image-based diagnosis has undergone great advances recently due to the rise of deep learning artificial intelligence. The work in this paper examines the applicability of raw deep transfer learning in classifying images of skin lesions into seven possible categories. Using the HAM1000 dataset of dermoscopy images, a system that accepts these images as input without explicit feature extraction or preprocessing was developed using 13 deep transfer learning models. Extensive evaluation revealed the advantages and shortcomings of such a method. Although some cancer types were correctly classified with high accuracy, the imbalance of the dataset, the small number of images in some categories, and the large number of classes reduced the best overall accuracy to 82.9%

Using deep transfer learning to detect scoliosis and spondylolisthesis from x-ray images.

Recent years have witnessed wider prevalence of vertebral column pathologies due to lifestyle changes, sedentary behaviors, or injuries. Spondylolisthesis and scoliosis are two of the most common ailments with an incidence of 5% and 3% in the United States population, respectively. Both of these abnormalities can affect children at a young age and, if left untreated, can progress into severe pain. Moreover, severe scoliosis can even lead to lung and heart problems. Thus, early diagnosis can make it easier to apply remedies/interventions and prevent further disease progression. Current diagnosis methods are based on visual inspection by physicians of radiographs and/or calculation of certain angles (e.g., Cobb angle). Traditional artificial intelligence-based diagnosis systems utilized these parameters to perform automated classification, which enabled fast and easy diagnosis supporting tools. However, they still require the specialists to perform error-prone tedious measurements. To this end, automated measurement tools were proposed based on processing techniques of X-ray images. In this paper, we utilize advances in deep transfer learning to diagnose spondylolisthesis and scoliosis from X-ray images without the need for any measurements. We collected raw data from real X-ray images of 338 subjects (i.e., 188 scoliosis, 79 spondylolisthesis, and 71 healthy). Deep transfer learning models were developed to perform three-class classification as well as pair-wise binary classifications among the three classes. The highest mean accuracy and maximum accuracy for three-class classification was 96.73% and 98.02%, respectively. Regarding pair-wise binary classification, high accuracy values were achieved for most of the models (i.e., > 98%). These results and other performance metrics reflect a robust ability to diagnose the subjects' vertebral column disorders from standard X-ray images. The current study provides a supporting tool that can reasonably help the physicians make the correct early diagnosis with less effort and errors, and reduce the need for surgical interventions

Approximating the Tail Probability of the t-Distribution: A Bayesian Approach

A Bayesian technique is used to approximate the tail probability of the t-distribution. A set of upper and lower bounds are obtained for this probability. Based on their simplicity and accuracy, these bounds are very adequate to use. Some members of these bounds are compared to some existing approximations. The possibility of using this new procedure for some other distributions is explored