Adaptive Graph via Multiple Kernel Learning for Nonnegative Matrix Factorization

Nonnegative Matrix Factorization (NMF) has been continuously evolving in several areas like pattern recognition and information retrieval methods. It factorizes a matrix into a product of 2 low-rank non-negative matrices that will define parts-based, and linear representation of nonnegative data. Recently, Graph regularized NMF (GrNMF) is proposed to find a compact representation,which uncovers the hidden semantics and simultaneously respects the intrinsic geometric structure. In GNMF, an affinity graph is constructed from the original data space to encode the geometrical information. In this paper, we propose a novel idea which engages a Multiple Kernel Learning approach into refining the graph structure that reflects the factorization of the matrix and the new data space. The GrNMF is improved by utilizing the graph refined by the kernel learning, and then a novel kernel learning method is introduced under the GrNMF framework. Our approach shows encouraging results of the proposed algorithm in comparison to the state-of-the-art clustering algorithms like NMF, GrNMF, SVD etc.Comment: This paper has been withdrawn by the author due to the terrible writin

ERASE: Energy Efficient Task Mapping and Resource Management for Work Stealing Runtimes

Parallel applications often rely on work stealing schedulers in combination with fine-grained tasking to achieve high performance and scalability. However, reducing the total energy consumption in the context of work stealing runtimes is still challenging, particularly when using asymmetric architectures with different types of CPU cores. A common approach for energy savings involves dynamic voltage and frequency scaling (DVFS) wherein throttling is carried out based on factors like task parallelism, stealing relations, and task criticality. This article makes the following observations: (i) leveraging DVFS on a per-task basis is impractical when using fine-grained tasking and in environments with cluster/chip-level DVFS; (ii) task moldability, wherein a single task can execute on multiple threads/cores via work-sharing, can help to reduce energy consumption; and (iii) mismatch between tasks and assigned resources (i.e., core type and number of cores) can detrimentally impact energy consumption. In this article, we propose EneRgy Aware SchedulEr (ERASE), an intra-application task scheduler on top of work stealing runtimes that aims to reduce the total energy consumption of parallel applications. It achieves energy savings by guiding scheduling decisions based on per-task energy consumption predictions of different resource configurations. In addition, ERASE is capable of adapting to both given static frequency settings and externally controlled DVFS. Overall, ERASE achieves up to 31% energy savings and improves performance by 44% on average, compared to the state-of-the-art DVFS-based schedulers

Comparison between ant colony and genetic algorithm using traveling salesman problem

The Travelling Salesman Problem (TSP) is a complex problem in combinatorial optimization. The aim of this study is compare the effect of using two distributed algorithm which are ant colony as a Swarm intelligence algorithm and genetic algorithm. In ant colony algorithm each individual ant constructs a part of the solution using an artificial pheromone which reflects its experience accumulated while solving the problem and heuristic information dependent on the problem. The results of comparison show that ant colony is high efficient than genetic algorithm and it requires less computational cost and generally only a few lines of code

Methodologies for Evaluating User Centric Performance of Mobile Network Applications

Performance is an important attribute of mobile software applications, having a direct impact on end-user's experience. One of the obstacles that make software performance testing difficult to pursue is the lack of performance requirements that complicates the process of verifying the correctness of the test case output. Moreover, compared to other platforms, mobile applications' quality assurance is more challenging, since their functionality is affected by the surrounding environment. In this work, we propose methodologies and frameworks to evaluate the impact of interaction of the quality of the wireless network connection and application configurations on performance behaviour and performance robustness of a mobile networked application as perceived by the end user. We follow a model-based approach. The thesis starts by defining the system model of software applications that we target, the network stack that the application is assumed to use to provide the service to the end user, and the metric used to capture the quality of the provided network service. Then, an analytical performance model that captures the application-network interactions is developed using the Markovian framework. To model realistic interactions with the network, the performance model is developed and solved using supplementary variable technique (SVT). The model is intensively verified with simulation. Furthermore, two input network models are analytically developed. In both models, the mobile application is assumed to have a wireless network access through a WiFi access point that implements IEEE 802.11 protocol. In the first model, data transfer is achieved using user datagram protocol (UDP), while in the second, data transfer is accomplished using transmission control protocol (TCP). For the TCP model, two scenarios are considered. In the first scenario, an application data unit (APDU) is assumed to fit in one TCP packet, while in the second scenario, an APDU is assumed to fit in multiple TCP packets. All models are verified using the well-known NS2 network simulator. Third, we propose a model based test generation methodology to evaluate the impact of the interaction of the environment, the wireless network, and the application configurations on the performance of a mobile networked application. The methodology requires four artefacts as inputs, namely, a behaviour model of the software under test, a network model, a test coverage criterion, and a set of desired performance levels. The methodology consists of three steps: performance model development, test generation, and estimation of test execution parameters. To evaluate the end-user quality of experience, test generation is formulated as an inversion problem and solved as an optimization problem. To generate an efficient set of test cases, two test coverage criteria are proposed: user experience (UE) and user experience and input interaction (UEII). Test execution optimizations are inferred using a performance simulation model. To show the applicability of the methodology, two mobile networked app examples are used: multimedia streaming and web browsing. The effectiveness of the methodology is evaluated by comparing the time cost to design a test suite with random testing. The obtained results are very promising. Fourth, to minimize the incurred cost of performance model evaluations, we utilize metamorphic testing to generate test cases. Metamorphic testing is a technique that is proposed to alleviate the test oracle problem. By utilizing certain inherent properties of the system under test (metamorphic relations), test cases are generated and verified without the need to know the expected output of each individual test case in advance. By hybridizing our proposed test generation methodology with metamorphic testing, the time cost of generating a test suite is reduced tremendously. We first generate a limited set of seed test cases using our test generation methodology. Then, we generate a set of follow-up test cases by utilizing the developed network models as metamorphic relations and without the need to invoke the performance model. Follow-up test generation is formulated as a maximization problem. The objective is to maximize the distance between a seed test case and follow-up test cases so that to generate a non-redundant set of test cases. Three distance metrics are used: Euclidean, squared Euclidean, and Manhattan. The modified methodology is used to generate test cases for a multimedia streaming application. We empirically evaluate the modified test generation methodology using two evaluation metrics: the incurred time cost and the percentage of redundancy in the generated test suite. The obtained results show the advantage of the modified methodology in minimizing the cost of test generation process. Fifth, we propose a third methodology to evaluate the impact of the wireless network conditions on robustness of performance of adaptive and non-adaptive mobile networked applications. Software robustness is mainly about how the system behaves under stressful conditions. In this work, we target performance robustness under stressful network conditions. The proposed methodology consists of three steps and it requires three different artefacts as inputs. To quantify robustness, two metrics (static and dynamic robustness) are proposed. The main challenge in evaluating robustness is the combinatorial growth of network-application interactions that need to be evaluated. To mitigate this issue, we propose an algorithm to limit the number of interactions, utilizing the monotonicity property of the performance model. To evaluate the dynamic robustness metric, the ability of the adaptive application to tolerate degraded network conditions has to be evaluated. This problem is formulated as a minimization problem. The methodology is used to evaluate the performance robustness of a mobile multimedia streaming application. The effectiveness of the proposed methodology is evaluated. The obtained results show three to five times reduction in total cost compared to the naive approach in which all combinations are exhaustively evaluated

VANET-Based Traffic Monitoring and Incident Detection System: A Review

As a component of intelligent transport systems (ITS), vehicular ad hoc network (VANET), which is a subform of manet, has been identified. It is established on the roads based on available vehicles and supporting road infrastructure, such as base stations. An accident can be defined as any activity in the environment that may be harmful to human life or dangerous to human life. In terms of early detection, and broadcast delay. VANET has shown various problems. The available technologies for incident detection and the corresponding algorithms for processing. The present problem and challenges of incident detection in VANET technology are discussed in this paper. The paper also reviews the recently proposed methods for early incident techniques and studies them

An insight into internet sector in Iraq

The internet is considered to be the most advanced technology today and a gateway to modern communication and the sharing of information, products, services, and technology. Nowadays, users want to be able to access anywhere and anytime several services and applications, which is increasing data traffic and triggering a mobile data explosion. Iraq has major problems in increasing the growth and use of the internet and changing the standard method of communication. This is a big challenge, however, since there are several variables that characterize this phase of transformation. In this paper, the problems, vision, and solutions are presented in details. This study aims to clarify the factors of internet use in Iraq by the use of an acceptable approach and by suggesting new solutions for all the presented problems. This work also, clarify the expected traffic and the mechanism to transform the traffic between local ISP’s networks (AS) internet exchange points

Reliable and efficient data dissemination schemein VANET: a review

Vehicular ad-hoc network (VANET), identified as a mobile ad hoc network MANETs with several added constraints. Basically, in VANETs, the network is established on the fly based on the availability of vehicles on roads and supporting infrastructures along the roads, such as base stations. Vehicles and road-side infrastructures are required to provide communication facilities, particularly when enough vehicles are not available on the roads for effective communication. VANETs are crucial for providing a wide range of safety and non-safety applications to road users. However, the specific fundamental problem in VANET is the challenge of creating effective communication between two fast-moving vehicles. Therefore, message routing is an issue for many safety and non-safety of VANETs applications. The challenge in designing a robust but reliable message dissemination technique is primarily due to the stringent QoS requirements of the VANETs safety applications. This paper investigated various methods and conducted literature on an idea to develop a model for efficient and reliable message dissemination routing techniques in VANET