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In this paper we present an exploratory smartphone usage study with logs collected from users in the wild, combined with the sociodemographic, technological and cultural information provided by them. We observe a high diversity among users' most used applications, but by classifying applications into services we find significant correlations between service usage and socio-demographic profile. We...
When Business support systems (BSS) suffer poor performance, the system administrator has to spot the problem of BSS as soon as possible. The monitoring system is a great help to quickly gain insight of the system from all sides. By the monitoring system, the administrator can evaluate various metrics on the different fields in one single arranged page and understands the whole picture of current...
Network Functions Virtualization (NFV) aims at replacing proprietary hardware appliances with software running on a standardized, general purpose computing platforms. Recently, the concept has gained traction in the industry and major deployments have been announced. However, benchmarking the performance characteristics of virtualized network functions (VNFs) is still an active research topic. VNFs...
Data provenance has been an active area of research as a means to standardize how the origin of data, process event history, and what or who was responsible for influencing results is explained. The common trend in capturing provenance is to collect all possible information, and then attempt to extract relevant information from the entire collection, which is not efficient especially at runtime. Unless...
Analyzing the behavioral patterns to maintain the workload in cloud computing is very important. There are number of cloud data centers that have the facility to maintain this. But this paper has provided the approach for resource utilization based on two metrics, energy and cost function. This approach works within the workload which helps to understand the relationship between users and servers,...
LocalMaxs extracts relevant multiword terms based on their cohesion but is computationally intensive, a critical issue for very large natural language corpora. The corpus properties concerning n-gram distribution determine the algorithm complexity and were empirically analyzed for corpora up to 982 million words. A parallel LocalMaxs implementation exhibits almost linear relative efficiency, speedup,...
Virtualization technology has been widely adoptedin Cloud data centers for adaptive resource provisioning. Withvirtualization, multiple virtual machines (VMs) can be colocatedon a single physical host to yield maximum efficiency. However, VMs which show high CPU utilization correlationsto other co-located peers are more likely to trigger overloadingincidents. This work provides an analysis on effects...
As the number of data centers increases, it is urgent to reduce their energy consumption. Although servers are becoming more energy-efficient, their idle consumption remains high, which is an issue as data centers are often over-provisioned. This work proposes a novel approach for building data centers with heterogeneous machines carefully chosen for their performance and energy efficiency ratios...
Energy consumption of today's datacenters is a constant concern from the standpoints of monetary and environmental costs. We model a datacenter as a queueing system, where each server can be switched on or off, with the time to switch a server on being nonnegligible. Previously derived structural properties of the optimal policy allow us to intelligently select policies to analyse further. Using the...
Data center efficiency is primarily sought by sharing physical resources, such as processors, memory, and disks in the form of virtual machines or containers among multiple users, i.e., workload consolidation. However, the reality is co-located applications in these virtual platforms compete for resources and interfere with each others' performance, resulting in performance variability/degradation...
DC/OS is a widely used distributed operating system that abstracts the resources of light-weighted virtualized datacenters, which is based on Mesos distributed systems kernel and user space services such as Marathon. It automates resource management and process scheduling, thus significantly impacts the performance of datacenters. In this paper, we propose Themis, a flexible, automatic and distributed...
This paper presents AUGURY, an application for the analysis of monitoring data from computers, servers or cloud infrastructures. The analysis is based on the extraction of patterns and trends from historical data, using elements of time-series analysis. The purpose of AUGURY is to aid a server administrator by forecasting the behaviour and resource usage of specific applications and in presenting...
Software evolution is a well-established research area, but not in the area of web systems/applications. Web projects are normally more complex than other software development projects because they have both server and client code, encompass a variety of programming languages, and are multidisciplinary. We aim to produce a catalog of web smells to help avoiding the problems in web development code...
In this paper, we present a combined experimental and analytical investigation of the impact of security compliance on a three-tier web application hosted on a virtualized platform. We used two-group experimental design for our experiments, and analyzed the impact of security using the ANCOVA model. The results of experiments suggest that security measures have significant impact on system performance...
We study the online load balancing problem for two independent criteria in heterogeneous systems. For convenience, we choose a system of distributed file servers located in a cluster as the scenario, although our work is not limited to it. Every server is assigned upper bounds for its load and storage space. We assume that the heterogeneity of servers is eventually reflected by the difference of these...
Privacy protection is critical for location-based services (LBS). A frequently proposed solution to protect location privacy suggests that the LBS users need to exchange their pseudonyms over time in protected regions called mix-zones. However, how to deploy mix-zones remains an open question and has not been well addressed in previous works. Inspired by the notion that "where you drive more...
In recent years, the fifth revision of the HyperText Markup Language standard (HTML5) has promoted the porting of traditional desktop applications to the Web, thus allowing the rise of Rich Internet Applications (RIAs). Additionally, the progressive support to Web Real-Time Communication (WebRTC) standard in modern browsers for real-time communications is accelerating this process, enabling the migration...
Server-centric data center networks enable several important features of modern data center applications, such as cloud storage and big data processing. However, network failures are ubiquitous and significantly affect network performance, such as routing correctness and network bandwidth. Existing server-centric data centers do not provide specific fault-tolerance mechanisms to recover the network...
Location-based services are popular server modes. However, location privacy problem in the Location-based services becomes a potential concern for service providers and users. In addition, existing obfuscation schemes downplay the effect of the privacy area and the practical road distribution in the areas. They mainly consider how to generate k dummies using either specific locations or randomly generated...
Deduplication technology has been increasingly used to reduce the primary storage cost. In practice, it often causes additional on-disk fragmentation that impairs the reading performance. Existing deduplication algorithms mainly focus on the static data layout design so that the random I/O requests are largely avoided and the harmful effect can be alleviated. However, our trace-driven emulations show...
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